fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/compat.h>
  34 #include <linux/bit_spinlock.h>
  35 #include <linux/xattr.h>
  36 #include <linux/posix_acl.h>
  37 #include <linux/falloc.h>
  38 #include <linux/slab.h>
  39 #include <linux/ratelimit.h>
  40 #include <linux/mount.h>
  41 #include <linux/btrfs.h>
  42 #include <linux/blkdev.h>
  43 #include <linux/posix_acl_xattr.h>
  44 #include <linux/uio.h>
  45 #include "ctree.h"
  46 #include "disk-io.h"
  47 #include "transaction.h"
  48 #include "btrfs_inode.h"
  49 #include "print-tree.h"
  50 #include "ordered-data.h"
  51 #include "xattr.h"
  52 #include "tree-log.h"
  53 #include "volumes.h"
  54 #include "compression.h"
  55 #include "locking.h"
  56 #include "free-space-cache.h"
  57 #include "inode-map.h"
  58 #include "backref.h"
  59 #include "hash.h"
  60 #include "props.h"
  61 #include "qgroup.h"
  62 #include "dedupe.h"
  63
  64 struct btrfs_iget_args {
  65         struct btrfs_key *location;
  66         struct btrfs_root *root;
  67 };
  68
  69 struct btrfs_dio_data {
  70         u64 outstanding_extents;
  71         u64 reserve;
  72         u64 unsubmitted_oe_range_start;
  73         u64 unsubmitted_oe_range_end;
  74 };
  75
  76 static const struct inode_operations btrfs_dir_inode_operations;
  77 static const struct inode_operations btrfs_symlink_inode_operations;
  78 static const struct inode_operations btrfs_dir_ro_inode_operations;
  79 static const struct inode_operations btrfs_special_inode_operations;
  80 static const struct inode_operations btrfs_file_inode_operations;
  81 static const struct address_space_operations btrfs_aops;
  82 static const struct address_space_operations btrfs_symlink_aops;
  83 static const struct file_operations btrfs_dir_file_operations;
  84 static const struct extent_io_ops btrfs_extent_io_ops;
  85
  86 static struct kmem_cache *btrfs_inode_cachep;
  87 struct kmem_cache *btrfs_trans_handle_cachep;
  88 struct kmem_cache *btrfs_transaction_cachep;
  89 struct kmem_cache *btrfs_path_cachep;
  90 struct kmem_cache *btrfs_free_space_cachep;
  91
  92 #define S_SHIFT 12
  93 static const unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  94         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  95         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  96         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  97         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  98         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  99         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
 100         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
 101 };
 102
 103 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
 104 static int btrfs_truncate(struct inode *inode);
 105 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
 106 static noinline int cow_file_range(struct inode *inode,
 107                                    struct page *locked_page,
 108                                    u64 start, u64 end, u64 delalloc_end,
 109                                    int *page_started, unsigned long *nr_written,
 110                                    int unlock, struct btrfs_dedupe_hash *hash);
 111 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 112                                            u64 len, u64 orig_start,
 113                                            u64 block_start, u64 block_len,
 114                                            u64 orig_block_len, u64 ram_bytes,
 115                                            int type);
 116
 117 static int btrfs_dirty_inode(struct inode *inode);
 118
 119 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 120 void btrfs_test_inode_set_ops(struct inode *inode)
 121 {
 122         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 123 }
 124 #endif
 125
 126 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 127                                      struct inode *inode,  struct inode *dir,
 128                                      const struct qstr *qstr)
 129 {
 130         int err;
 131
 132         err = btrfs_init_acl(trans, inode, dir);
 133         if (!err)
 134                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 135         return err;
 136 }
 137
 138 /*
 139  * this does all the hard work for inserting an inline extent into
 140  * the btree.  The caller should have done a btrfs_drop_extents so that
 141  * no overlapping inline items exist in the btree
 142  */
 143 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 144                                 struct btrfs_path *path, int extent_inserted,
 145                                 struct btrfs_root *root, struct inode *inode,
 146                                 u64 start, size_t size, size_t compressed_size,
 147                                 int compress_type,
 148                                 struct page **compressed_pages)
 149 {
 150         struct extent_buffer *leaf;
 151         struct page *page = NULL;
 152         char *kaddr;
 153         unsigned long ptr;
 154         struct btrfs_file_extent_item *ei;
 155         int err = 0;
 156         int ret;
 157         size_t cur_size = size;
 158         unsigned long offset;
 159
 160         if (compressed_size && compressed_pages)
 161                 cur_size = compressed_size;
 162
 163         inode_add_bytes(inode, size);
 164
 165         if (!extent_inserted) {
 166                 struct btrfs_key key;
 167                 size_t datasize;
 168
 169                 key.objectid = btrfs_ino(inode);
 170                 key.offset = start;
 171                 key.type = BTRFS_EXTENT_DATA_KEY;
 172
 173                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 174                 path->leave_spinning = 1;
 175                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 176                                               datasize);
 177                 if (ret) {
 178                         err = ret;
 179                         goto fail;
 180                 }
 181         }
 182         leaf = path->nodes[0];
 183         ei = btrfs_item_ptr(leaf, path->slots[0],
 184                             struct btrfs_file_extent_item);
 185         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 186         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 187         btrfs_set_file_extent_encryption(leaf, ei, 0);
 188         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 189         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 190         ptr = btrfs_file_extent_inline_start(ei);
 191
 192         if (compress_type != BTRFS_COMPRESS_NONE) {
 193                 struct page *cpage;
 194                 int i = 0;
 195                 while (compressed_size > 0) {
 196                         cpage = compressed_pages[i];
 197                         cur_size = min_t(unsigned long, compressed_size,
 198                                        PAGE_SIZE);
 199
 200                         kaddr = kmap_atomic(cpage);
 201                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 202                         kunmap_atomic(kaddr);
 203
 204                         i++;
 205                         ptr += cur_size;
 206                         compressed_size -= cur_size;
 207                 }
 208                 btrfs_set_file_extent_compression(leaf, ei,
 209                                                   compress_type);
 210         } else {
 211                 page = find_get_page(inode->i_mapping,
 212                                      start >> PAGE_SHIFT);
 213                 btrfs_set_file_extent_compression(leaf, ei, 0);
 214                 kaddr = kmap_atomic(page);
 215                 offset = start & (PAGE_SIZE - 1);
 216                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 217                 kunmap_atomic(kaddr);
 218                 put_page(page);
 219         }
 220         btrfs_mark_buffer_dirty(leaf);
 221         btrfs_release_path(path);
 222
 223         /*
 224          * we're an inline extent, so nobody can
 225          * extend the file past i_size without locking
 226          * a page we already have locked.
 227          *
 228          * We must do any isize and inode updates
 229          * before we unlock the pages.  Otherwise we
 230          * could end up racing with unlink.
 231          */
 232         BTRFS_I(inode)->disk_i_size = inode->i_size;
 233         ret = btrfs_update_inode(trans, root, inode);
 234
 235         return ret;
 236 fail:
 237         return err;
 238 }
 239
 240
 241 /*
 242  * conditionally insert an inline extent into the file.  This
 243  * does the checks required to make sure the data is small enough
 244  * to fit as an inline extent.
 245  */
 246 static noinline int cow_file_range_inline(struct btrfs_root *root,
 247                                           struct inode *inode, u64 start,
 248                                           u64 end, size_t compressed_size,
 249                                           int compress_type,
 250                                           struct page **compressed_pages)
 251 {
 252         struct btrfs_fs_info *fs_info = root->fs_info;
 253         struct btrfs_trans_handle *trans;
 254         u64 isize = i_size_read(inode);
 255         u64 actual_end = min(end + 1, isize);
 256         u64 inline_len = actual_end - start;
 257         u64 aligned_end = ALIGN(end, fs_info->sectorsize);
 258         u64 data_len = inline_len;
 259         int ret;
 260         struct btrfs_path *path;
 261         int extent_inserted = 0;
 262         u32 extent_item_size;
 263
 264         if (compressed_size)
 265                 data_len = compressed_size;
 266
 267         if (start > 0 ||
 268             actual_end > fs_info->sectorsize ||
 269             data_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info) ||
 270             (!compressed_size &&
 271             (actual_end & (fs_info->sectorsize - 1)) == 0) ||
 272             end + 1 < isize ||
 273             data_len > fs_info->max_inline) {
 274                 return 1;
 275         }
 276
 277         path = btrfs_alloc_path();
 278         if (!path)
 279                 return -ENOMEM;
 280
 281         trans = btrfs_join_transaction(root);
 282         if (IS_ERR(trans)) {
 283                 btrfs_free_path(path);
 284                 return PTR_ERR(trans);
 285         }
 286         trans->block_rsv = &fs_info->delalloc_block_rsv;
 287
 288         if (compressed_size && compressed_pages)
 289                 extent_item_size = btrfs_file_extent_calc_inline_size(
 290                    compressed_size);
 291         else
 292                 extent_item_size = btrfs_file_extent_calc_inline_size(
 293                     inline_len);
 294
 295         ret = __btrfs_drop_extents(trans, root, inode, path,
 296                                    start, aligned_end, NULL,
 297                                    1, 1, extent_item_size, &extent_inserted);
 298         if (ret) {
 299                 btrfs_abort_transaction(trans, ret);
 300                 goto out;
 301         }
 302
 303         if (isize > actual_end)
 304                 inline_len = min_t(u64, isize, actual_end);
 305         ret = insert_inline_extent(trans, path, extent_inserted,
 306                                    root, inode, start,
 307                                    inline_len, compressed_size,
 308                                    compress_type, compressed_pages);
 309         if (ret && ret != -ENOSPC) {
 310                 btrfs_abort_transaction(trans, ret);
 311                 goto out;
 312         } else if (ret == -ENOSPC) {
 313                 ret = 1;
 314                 goto out;
 315         }
 316
 317         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 318         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 319         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 320 out:
 321         /*
 322          * Don't forget to free the reserved space, as for inlined extent
 323          * it won't count as data extent, free them directly here.
 324          * And at reserve time, it's always aligned to page size, so
 325          * just free one page here.
 326          */
 327         btrfs_qgroup_free_data(inode, 0, PAGE_SIZE);
 328         btrfs_free_path(path);
 329         btrfs_end_transaction(trans, root);
 330         return ret;
 331 }
 332
 333 struct async_extent {
 334         u64 start;
 335         u64 ram_size;
 336         u64 compressed_size;
 337         struct page **pages;
 338         unsigned long nr_pages;
 339         int compress_type;
 340         struct list_head list;
 341 };
 342
 343 struct async_cow {
 344         struct inode *inode;
 345         struct btrfs_root *root;
 346         struct page *locked_page;
 347         u64 start;
 348         u64 end;
 349         struct list_head extents;
 350         struct btrfs_work work;
 351 };
 352
 353 static noinline int add_async_extent(struct async_cow *cow,
 354                                      u64 start, u64 ram_size,
 355                                      u64 compressed_size,
 356                                      struct page **pages,
 357                                      unsigned long nr_pages,
 358                                      int compress_type)
 359 {
 360         struct async_extent *async_extent;
 361
 362         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 363         BUG_ON(!async_extent); /* -ENOMEM */
 364         async_extent->start = start;
 365         async_extent->ram_size = ram_size;
 366         async_extent->compressed_size = compressed_size;
 367         async_extent->pages = pages;
 368         async_extent->nr_pages = nr_pages;
 369         async_extent->compress_type = compress_type;
 370         list_add_tail(&async_extent->list, &cow->extents);
 371         return 0;
 372 }
 373
 374 static inline int inode_need_compress(struct inode *inode)
 375 {
 376         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 377
 378         /* force compress */
 379         if (btrfs_test_opt(fs_info, FORCE_COMPRESS))
 380                 return 1;
 381         /* bad compression ratios */
 382         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 383                 return 0;
 384         if (btrfs_test_opt(fs_info, COMPRESS) ||
 385             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 386             BTRFS_I(inode)->force_compress)
 387                 return 1;
 388         return 0;
 389 }
 390
 391 /*
 392  * we create compressed extents in two phases.  The first
 393  * phase compresses a range of pages that have already been
 394  * locked (both pages and state bits are locked).
 395  *
 396  * This is done inside an ordered work queue, and the compression
 397  * is spread across many cpus.  The actual IO submission is step
 398  * two, and the ordered work queue takes care of making sure that
 399  * happens in the same order things were put onto the queue by
 400  * writepages and friends.
 401  *
 402  * If this code finds it can't get good compression, it puts an
 403  * entry onto the work queue to write the uncompressed bytes.  This
 404  * makes sure that both compressed inodes and uncompressed inodes
 405  * are written in the same order that the flusher thread sent them
 406  * down.
 407  */
 408 static noinline void compress_file_range(struct inode *inode,
 409                                         struct page *locked_page,
 410                                         u64 start, u64 end,
 411                                         struct async_cow *async_cow,
 412                                         int *num_added)
 413 {
 414         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 415         struct btrfs_root *root = BTRFS_I(inode)->root;
 416         u64 num_bytes;
 417         u64 blocksize = fs_info->sectorsize;
 418         u64 actual_end;
 419         u64 isize = i_size_read(inode);
 420         int ret = 0;
 421         struct page **pages = NULL;
 422         unsigned long nr_pages;
 423         unsigned long nr_pages_ret = 0;
 424         unsigned long total_compressed = 0;
 425         unsigned long total_in = 0;
 426         unsigned long max_compressed = SZ_128K;
 427         unsigned long max_uncompressed = SZ_128K;
 428         int i;
 429         int will_compress;
 430         int compress_type = fs_info->compress_type;
 431         int redirty = 0;
 432
 433         /* if this is a small write inside eof, kick off a defrag */
 434         if ((end - start + 1) < SZ_16K &&
 435             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 436                 btrfs_add_inode_defrag(NULL, inode);
 437
 438         actual_end = min_t(u64, isize, end + 1);
 439 again:
 440         will_compress = 0;
 441         nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 442         nr_pages = min_t(unsigned long, nr_pages, SZ_128K / PAGE_SIZE);
 443
 444         /*
 445          * we don't want to send crud past the end of i_size through
 446          * compression, that's just a waste of CPU time.  So, if the
 447          * end of the file is before the start of our current
 448          * requested range of bytes, we bail out to the uncompressed
 449          * cleanup code that can deal with all of this.
 450          *
 451          * It isn't really the fastest way to fix things, but this is a
 452          * very uncommon corner.
 453          */
 454         if (actual_end <= start)
 455                 goto cleanup_and_bail_uncompressed;
 456
 457         total_compressed = actual_end - start;
 458
 459         /*
 460          * skip compression for a small file range(<=blocksize) that
 461          * isn't an inline extent, since it doesn't save disk space at all.
 462          */
 463         if (total_compressed <= blocksize &&
 464            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 465                 goto cleanup_and_bail_uncompressed;
 466
 467         /* we want to make sure that amount of ram required to uncompress
 468          * an extent is reasonable, so we limit the total size in ram
 469          * of a compressed extent to 128k.  This is a crucial number
 470          * because it also controls how easily we can spread reads across
 471          * cpus for decompression.
 472          *
 473          * We also want to make sure the amount of IO required to do
 474          * a random read is reasonably small, so we limit the size of
 475          * a compressed extent to 128k.
 476          */
 477         total_compressed = min(total_compressed, max_uncompressed);
 478         num_bytes = ALIGN(end - start + 1, blocksize);
 479         num_bytes = max(blocksize,  num_bytes);
 480         total_in = 0;
 481         ret = 0;
 482
 483         /*
 484          * we do compression for mount -o compress and when the
 485          * inode has not been flagged as nocompress.  This flag can
 486          * change at any time if we discover bad compression ratios.
 487          */
 488         if (inode_need_compress(inode)) {
 489                 WARN_ON(pages);
 490                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 491                 if (!pages) {
 492                         /* just bail out to the uncompressed code */
 493                         goto cont;
 494                 }
 495
 496                 if (BTRFS_I(inode)->force_compress)
 497                         compress_type = BTRFS_I(inode)->force_compress;
 498
 499                 /*
 500                  * we need to call clear_page_dirty_for_io on each
 501                  * page in the range.  Otherwise applications with the file
 502                  * mmap'd can wander in and change the page contents while
 503                  * we are compressing them.
 504                  *
 505                  * If the compression fails for any reason, we set the pages
 506                  * dirty again later on.
 507                  */
 508                 extent_range_clear_dirty_for_io(inode, start, end);
 509                 redirty = 1;
 510                 ret = btrfs_compress_pages(compress_type,
 511                                            inode->i_mapping, start,
 512                                            total_compressed, pages,
 513                                            nr_pages, &nr_pages_ret,
 514                                            &total_in,
 515                                            &total_compressed,
 516                                            max_compressed);
 517
 518                 if (!ret) {
 519                         unsigned long offset = total_compressed &
 520                                 (PAGE_SIZE - 1);
 521                         struct page *page = pages[nr_pages_ret - 1];
 522                         char *kaddr;
 523
 524                         /* zero the tail end of the last page, we might be
 525                          * sending it down to disk
 526                          */
 527                         if (offset) {
 528                                 kaddr = kmap_atomic(page);
 529                                 memset(kaddr + offset, 0,
 530                                        PAGE_SIZE - offset);
 531                                 kunmap_atomic(kaddr);
 532                         }
 533                         will_compress = 1;
 534                 }
 535         }
 536 cont:
 537         if (start == 0) {
 538                 /* lets try to make an inline extent */
 539                 if (ret || total_in < (actual_end - start)) {
 540                         /* we didn't compress the entire range, try
 541                          * to make an uncompressed inline extent.
 542                          */
 543                         ret = cow_file_range_inline(root, inode, start, end,
 544                                                     0, 0, NULL);
 545                 } else {
 546                         /* try making a compressed inline extent */
 547                         ret = cow_file_range_inline(root, inode, start, end,
 548                                                     total_compressed,
 549                                                     compress_type, pages);
 550                 }
 551                 if (ret <= 0) {
 552                         unsigned long clear_flags = EXTENT_DELALLOC |
 553                                 EXTENT_DEFRAG;
 554                         unsigned long page_error_op;
 555
 556                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 557                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 558
 559                         /*
 560                          * inline extent creation worked or returned error,
 561                          * we don't need to create any more async work items.
 562                          * Unlock and free up our temp pages.
 563                          */
 564                         extent_clear_unlock_delalloc(inode, start, end, end,
 565                                                      NULL, clear_flags,
 566                                                      PAGE_UNLOCK |
 567                                                      PAGE_CLEAR_DIRTY |
 568                                                      PAGE_SET_WRITEBACK |
 569                                                      page_error_op |
 570                                                      PAGE_END_WRITEBACK);
 571                         btrfs_free_reserved_data_space_noquota(inode, start,
 572                                                 end - start + 1);
 573                         goto free_pages_out;
 574                 }
 575         }
 576
 577         if (will_compress) {
 578                 /*
 579                  * we aren't doing an inline extent round the compressed size
 580                  * up to a block size boundary so the allocator does sane
 581                  * things
 582                  */
 583                 total_compressed = ALIGN(total_compressed, blocksize);
 584
 585                 /*
 586                  * one last check to make sure the compression is really a
 587                  * win, compare the page count read with the blocks on disk
 588                  */
 589                 total_in = ALIGN(total_in, PAGE_SIZE);
 590                 if (total_compressed >= total_in) {
 591                         will_compress = 0;
 592                 } else {
 593                         num_bytes = total_in;
 594                         *num_added += 1;
 595
 596                         /*
 597                          * The async work queues will take care of doing actual
 598                          * allocation on disk for these compressed pages, and
 599                          * will submit them to the elevator.
 600                          */
 601                         add_async_extent(async_cow, start, num_bytes,
 602                                         total_compressed, pages, nr_pages_ret,
 603                                         compress_type);
 604
 605                         if (start + num_bytes < end) {
 606                                 start += num_bytes;
 607                                 pages = NULL;
 608                                 cond_resched();
 609                                 goto again;
 610                         }
 611                         return;
 612                 }
 613         }
 614         if (pages) {
 615                 /*
 616                  * the compression code ran but failed to make things smaller,
 617                  * free any pages it allocated and our page pointer array
 618                  */
 619                 for (i = 0; i < nr_pages_ret; i++) {
 620                         WARN_ON(pages[i]->mapping);
 621                         put_page(pages[i]);
 622                 }
 623                 kfree(pages);
 624                 pages = NULL;
 625                 total_compressed = 0;
 626                 nr_pages_ret = 0;
 627
 628                 /* flag the file so we don't compress in the future */
 629                 if (!btrfs_test_opt(fs_info, FORCE_COMPRESS) &&
 630                     !(BTRFS_I(inode)->force_compress)) {
 631                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 632                 }
 633         }
 634 cleanup_and_bail_uncompressed:
 635         /*
 636          * No compression, but we still need to write the pages in the file
 637          * we've been given so far.  redirty the locked page if it corresponds
 638          * to our extent and set things up for the async work queue to run
 639          * cow_file_range to do the normal delalloc dance.
 640          */
 641         if (page_offset(locked_page) >= start &&
 642             page_offset(locked_page) <= end)
 643                 __set_page_dirty_nobuffers(locked_page);
 644                 /* unlocked later on in the async handlers */
 645
 646         if (redirty)
 647                 extent_range_redirty_for_io(inode, start, end);
 648         add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0,
 649                          BTRFS_COMPRESS_NONE);
 650         *num_added += 1;
 651
 652         return;
 653
 654 free_pages_out:
 655         for (i = 0; i < nr_pages_ret; i++) {
 656                 WARN_ON(pages[i]->mapping);
 657                 put_page(pages[i]);
 658         }
 659         kfree(pages);
 660 }
 661
 662 static void free_async_extent_pages(struct async_extent *async_extent)
 663 {
 664         int i;
 665
 666         if (!async_extent->pages)
 667                 return;
 668
 669         for (i = 0; i < async_extent->nr_pages; i++) {
 670                 WARN_ON(async_extent->pages[i]->mapping);
 671                 put_page(async_extent->pages[i]);
 672         }
 673         kfree(async_extent->pages);
 674         async_extent->nr_pages = 0;
 675         async_extent->pages = NULL;
 676 }
 677
 678 /*
 679  * phase two of compressed writeback.  This is the ordered portion
 680  * of the code, which only gets called in the order the work was
 681  * queued.  We walk all the async extents created by compress_file_range
 682  * and send them down to the disk.
 683  */
 684 static noinline void submit_compressed_extents(struct inode *inode,
 685                                               struct async_cow *async_cow)
 686 {
 687         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 688         struct async_extent *async_extent;
 689         u64 alloc_hint = 0;
 690         struct btrfs_key ins;
 691         struct extent_map *em;
 692         struct btrfs_root *root = BTRFS_I(inode)->root;
 693         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 694         struct extent_io_tree *io_tree;
 695         int ret = 0;
 696
 697 again:
 698         while (!list_empty(&async_cow->extents)) {
 699                 async_extent = list_entry(async_cow->extents.next,
 700                                           struct async_extent, list);
 701                 list_del(&async_extent->list);
 702
 703                 io_tree = &BTRFS_I(inode)->io_tree;
 704
 705 retry:
 706                 /* did the compression code fall back to uncompressed IO? */
 707                 if (!async_extent->pages) {
 708                         int page_started = 0;
 709                         unsigned long nr_written = 0;
 710
 711                         lock_extent(io_tree, async_extent->start,
 712                                          async_extent->start +
 713                                          async_extent->ram_size - 1);
 714
 715                         /* allocate blocks */
 716                         ret = cow_file_range(inode, async_cow->locked_page,
 717                                              async_extent->start,
 718                                              async_extent->start +
 719                                              async_extent->ram_size - 1,
 720                                              async_extent->start +
 721                                              async_extent->ram_size - 1,
 722                                              &page_started, &nr_written, 0,
 723                                              NULL);
 724
 725                         /* JDM XXX */
 726
 727                         /*
 728                          * if page_started, cow_file_range inserted an
 729                          * inline extent and took care of all the unlocking
 730                          * and IO for us.  Otherwise, we need to submit
 731                          * all those pages down to the drive.
 732                          */
 733                         if (!page_started && !ret)
 734                                 extent_write_locked_range(io_tree,
 735                                                   inode, async_extent->start,
 736                                                   async_extent->start +
 737                                                   async_extent->ram_size - 1,
 738                                                   btrfs_get_extent,
 739                                                   WB_SYNC_ALL);
 740                         else if (ret)
 741                                 unlock_page(async_cow->locked_page);
 742                         kfree(async_extent);
 743                         cond_resched();
 744                         continue;
 745                 }
 746
 747                 lock_extent(io_tree, async_extent->start,
 748                             async_extent->start + async_extent->ram_size - 1);
 749
 750                 ret = btrfs_reserve_extent(root, async_extent->ram_size,
 751                                            async_extent->compressed_size,
 752                                            async_extent->compressed_size,
 753                                            0, alloc_hint, &ins, 1, 1);
 754                 if (ret) {
 755                         free_async_extent_pages(async_extent);
 756
 757                         if (ret == -ENOSPC) {
 758                                 unlock_extent(io_tree, async_extent->start,
 759                                               async_extent->start +
 760                                               async_extent->ram_size - 1);
 761
 762                                 /*
 763                                  * we need to redirty the pages if we decide to
 764                                  * fallback to uncompressed IO, otherwise we
 765                                  * will not submit these pages down to lower
 766                                  * layers.
 767                                  */
 768                                 extent_range_redirty_for_io(inode,
 769                                                 async_extent->start,
 770                                                 async_extent->start +
 771                                                 async_extent->ram_size - 1);
 772
 773                                 goto retry;
 774                         }
 775                         goto out_free;
 776                 }
 777                 /*
 778                  * here we're doing allocation and writeback of the
 779                  * compressed pages
 780                  */
 781                 btrfs_drop_extent_cache(inode, async_extent->start,
 782                                         async_extent->start +
 783                                         async_extent->ram_size - 1, 0);
 784
 785                 em = alloc_extent_map();
 786                 if (!em) {
 787                         ret = -ENOMEM;
 788                         goto out_free_reserve;
 789                 }
 790                 em->start = async_extent->start;
 791                 em->len = async_extent->ram_size;
 792                 em->orig_start = em->start;
 793                 em->mod_start = em->start;
 794                 em->mod_len = em->len;
 795
 796                 em->block_start = ins.objectid;
 797                 em->block_len = ins.offset;
 798                 em->orig_block_len = ins.offset;
 799                 em->ram_bytes = async_extent->ram_size;
 800                 em->bdev = fs_info->fs_devices->latest_bdev;
 801                 em->compress_type = async_extent->compress_type;
 802                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 803                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 804                 em->generation = -1;
 805
 806                 while (1) {
 807                         write_lock(&em_tree->lock);
 808                         ret = add_extent_mapping(em_tree, em, 1);
 809                         write_unlock(&em_tree->lock);
 810                         if (ret != -EEXIST) {
 811                                 free_extent_map(em);
 812                                 break;
 813                         }
 814                         btrfs_drop_extent_cache(inode, async_extent->start,
 815                                                 async_extent->start +
 816                                                 async_extent->ram_size - 1, 0);
 817                 }
 818
 819                 if (ret)
 820                         goto out_free_reserve;
 821
 822                 ret = btrfs_add_ordered_extent_compress(inode,
 823                                                 async_extent->start,
 824                                                 ins.objectid,
 825                                                 async_extent->ram_size,
 826                                                 ins.offset,
 827                                                 BTRFS_ORDERED_COMPRESSED,
 828                                                 async_extent->compress_type);
 829                 if (ret) {
 830                         btrfs_drop_extent_cache(inode, async_extent->start,
 831                                                 async_extent->start +
 832                                                 async_extent->ram_size - 1, 0);
 833                         goto out_free_reserve;
 834                 }
 835                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 836
 837                 /*
 838                  * clear dirty, set writeback and unlock the pages.
 839                  */
 840                 extent_clear_unlock_delalloc(inode, async_extent->start,
 841                                 async_extent->start +
 842                                 async_extent->ram_size - 1,
 843                                 async_extent->start +
 844                                 async_extent->ram_size - 1,
 845                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 846                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 847                                 PAGE_SET_WRITEBACK);
 848                 ret = btrfs_submit_compressed_write(inode,
 849                                     async_extent->start,
 850                                     async_extent->ram_size,
 851                                     ins.objectid,
 852                                     ins.offset, async_extent->pages,
 853                                     async_extent->nr_pages);
 854                 if (ret) {
 855                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 856                         struct page *p = async_extent->pages[0];
 857                         const u64 start = async_extent->start;
 858                         const u64 end = start + async_extent->ram_size - 1;
 859
 860                         p->mapping = inode->i_mapping;
 861                         tree->ops->writepage_end_io_hook(p, start, end,
 862                                                          NULL, 0);
 863                         p->mapping = NULL;
 864                         extent_clear_unlock_delalloc(inode, start, end, end,
 865                                                      NULL, 0,
 866                                                      PAGE_END_WRITEBACK |
 867                                                      PAGE_SET_ERROR);
 868                         free_async_extent_pages(async_extent);
 869                 }
 870                 alloc_hint = ins.objectid + ins.offset;
 871                 kfree(async_extent);
 872                 cond_resched();
 873         }
 874         return;
 875 out_free_reserve:
 876         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 877         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
 878 out_free:
 879         extent_clear_unlock_delalloc(inode, async_extent->start,
 880                                      async_extent->start +
 881                                      async_extent->ram_size - 1,
 882                                      async_extent->start +
 883                                      async_extent->ram_size - 1,
 884                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 885                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 886                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 887                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 888                                      PAGE_SET_ERROR);
 889         free_async_extent_pages(async_extent);
 890         kfree(async_extent);
 891         goto again;
 892 }
 893
 894 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 895                                       u64 num_bytes)
 896 {
 897         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 898         struct extent_map *em;
 899         u64 alloc_hint = 0;
 900
 901         read_lock(&em_tree->lock);
 902         em = search_extent_mapping(em_tree, start, num_bytes);
 903         if (em) {
 904                 /*
 905                  * if block start isn't an actual block number then find the
 906                  * first block in this inode and use that as a hint.  If that
 907                  * block is also bogus then just don't worry about it.
 908                  */
 909                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 910                         free_extent_map(em);
 911                         em = search_extent_mapping(em_tree, 0, 0);
 912                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 913                                 alloc_hint = em->block_start;
 914                         if (em)
 915                                 free_extent_map(em);
 916                 } else {
 917                         alloc_hint = em->block_start;
 918                         free_extent_map(em);
 919                 }
 920         }
 921         read_unlock(&em_tree->lock);
 922
 923         return alloc_hint;
 924 }
 925
 926 /*
 927  * when extent_io.c finds a delayed allocation range in the file,
 928  * the call backs end up in this code.  The basic idea is to
 929  * allocate extents on disk for the range, and create ordered data structs
 930  * in ram to track those extents.
 931  *
 932  * locked_page is the page that writepage had locked already.  We use
 933  * it to make sure we don't do extra locks or unlocks.
 934  *
 935  * *page_started is set to one if we unlock locked_page and do everything
 936  * required to start IO on it.  It may be clean and already done with
 937  * IO when we return.
 938  */
 939 static noinline int cow_file_range(struct inode *inode,
 940                                    struct page *locked_page,
 941                                    u64 start, u64 end, u64 delalloc_end,
 942                                    int *page_started, unsigned long *nr_written,
 943                                    int unlock, struct btrfs_dedupe_hash *hash)
 944 {
 945         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 946         struct btrfs_root *root = BTRFS_I(inode)->root;
 947         u64 alloc_hint = 0;
 948         u64 num_bytes;
 949         unsigned long ram_size;
 950         u64 disk_num_bytes;
 951         u64 cur_alloc_size;
 952         u64 blocksize = fs_info->sectorsize;
 953         struct btrfs_key ins;
 954         struct extent_map *em;
 955         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 956         int ret = 0;
 957
 958         if (btrfs_is_free_space_inode(inode)) {
 959                 WARN_ON_ONCE(1);
 960                 ret = -EINVAL;
 961                 goto out_unlock;
 962         }
 963
 964         num_bytes = ALIGN(end - start + 1, blocksize);
 965         num_bytes = max(blocksize,  num_bytes);
 966         disk_num_bytes = num_bytes;
 967
 968         /* if this is a small write inside eof, kick off defrag */
 969         if (num_bytes < SZ_64K &&
 970             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 971                 btrfs_add_inode_defrag(NULL, inode);
 972
 973         if (start == 0) {
 974                 /* lets try to make an inline extent */
 975                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 976                                             NULL);
 977                 if (ret == 0) {
 978                         extent_clear_unlock_delalloc(inode, start, end,
 979                                      delalloc_end, NULL,
 980                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 981                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 982                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 983                                      PAGE_END_WRITEBACK);
 984                         btrfs_free_reserved_data_space_noquota(inode, start,
 985                                                 end - start + 1);
 986                         *nr_written = *nr_written +
 987                              (end - start + PAGE_SIZE) / PAGE_SIZE;
 988                         *page_started = 1;
 989                         goto out;
 990                 } else if (ret < 0) {
 991                         goto out_unlock;
 992                 }
 993         }
 994
 995         BUG_ON(disk_num_bytes >
 996                btrfs_super_total_bytes(fs_info->super_copy));
 997
 998         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 999         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
1000
1001         while (disk_num_bytes > 0) {
1002                 unsigned long op;
1003
1004                 cur_alloc_size = disk_num_bytes;
1005                 ret = btrfs_reserve_extent(root, cur_alloc_size, cur_alloc_size,
1006                                            fs_info->sectorsize, 0, alloc_hint,
1007                                            &ins, 1, 1);
1008                 if (ret < 0)
1009                         goto out_unlock;
1010
1011                 em = alloc_extent_map();
1012                 if (!em) {
1013                         ret = -ENOMEM;
1014                         goto out_reserve;
1015                 }
1016                 em->start = start;
1017                 em->orig_start = em->start;
1018                 ram_size = ins.offset;
1019                 em->len = ins.offset;
1020                 em->mod_start = em->start;
1021                 em->mod_len = em->len;
1022
1023                 em->block_start = ins.objectid;
1024                 em->block_len = ins.offset;
1025                 em->orig_block_len = ins.offset;
1026                 em->ram_bytes = ram_size;
1027                 em->bdev = fs_info->fs_devices->latest_bdev;
1028                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
1029                 em->generation = -1;
1030
1031                 while (1) {
1032                         write_lock(&em_tree->lock);
1033                         ret = add_extent_mapping(em_tree, em, 1);
1034                         write_unlock(&em_tree->lock);
1035                         if (ret != -EEXIST) {
1036                                 free_extent_map(em);
1037                                 break;
1038                         }
1039                         btrfs_drop_extent_cache(inode, start,
1040                                                 start + ram_size - 1, 0);
1041                 }
1042                 if (ret)
1043                         goto out_reserve;
1044
1045                 cur_alloc_size = ins.offset;
1046                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1047                                                ram_size, cur_alloc_size, 0);
1048                 if (ret)
1049                         goto out_drop_extent_cache;
1050
1051                 if (root->root_key.objectid ==
1052                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1053                         ret = btrfs_reloc_clone_csums(inode, start,
1054                                                       cur_alloc_size);
1055                         if (ret)
1056                                 goto out_drop_extent_cache;
1057                 }
1058
1059                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1060
1061                 if (disk_num_bytes < cur_alloc_size)
1062                         break;
1063
1064                 /* we're not doing compressed IO, don't unlock the first
1065                  * page (which the caller expects to stay locked), don't
1066                  * clear any dirty bits and don't set any writeback bits
1067                  *
1068                  * Do set the Private2 bit so we know this page was properly
1069                  * setup for writepage
1070                  */
1071                 op = unlock ? PAGE_UNLOCK : 0;
1072                 op |= PAGE_SET_PRIVATE2;
1073
1074                 extent_clear_unlock_delalloc(inode, start,
1075                                              start + ram_size - 1,
1076                                              delalloc_end, locked_page,
1077                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1078                                              op);
1079                 disk_num_bytes -= cur_alloc_size;
1080                 num_bytes -= cur_alloc_size;
1081                 alloc_hint = ins.objectid + ins.offset;
1082                 start += cur_alloc_size;
1083         }
1084 out:
1085         return ret;
1086
1087 out_drop_extent_cache:
1088         btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0);
1089 out_reserve:
1090         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1091         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
1092 out_unlock:
1093         extent_clear_unlock_delalloc(inode, start, end, delalloc_end,
1094                                      locked_page,
1095                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1096                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1097                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1098                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1099         goto out;
1100 }
1101
1102 /*
1103  * work queue call back to started compression on a file and pages
1104  */
1105 static noinline void async_cow_start(struct btrfs_work *work)
1106 {
1107         struct async_cow *async_cow;
1108         int num_added = 0;
1109         async_cow = container_of(work, struct async_cow, work);
1110
1111         compress_file_range(async_cow->inode, async_cow->locked_page,
1112                             async_cow->start, async_cow->end, async_cow,
1113                             &num_added);
1114         if (num_added == 0) {
1115                 btrfs_add_delayed_iput(async_cow->inode);
1116                 async_cow->inode = NULL;
1117         }
1118 }
1119
1120 /*
1121  * work queue call back to submit previously compressed pages
1122  */
1123 static noinline void async_cow_submit(struct btrfs_work *work)
1124 {
1125         struct btrfs_fs_info *fs_info;
1126         struct async_cow *async_cow;
1127         struct btrfs_root *root;
1128         unsigned long nr_pages;
1129
1130         async_cow = container_of(work, struct async_cow, work);
1131
1132         root = async_cow->root;
1133         fs_info = root->fs_info;
1134         nr_pages = (async_cow->end - async_cow->start + PAGE_SIZE) >>
1135                 PAGE_SHIFT;
1136
1137         /*
1138          * atomic_sub_return implies a barrier for waitqueue_active
1139          */
1140         if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) <
1141             5 * SZ_1M &&
1142             waitqueue_active(&fs_info->async_submit_wait))
1143                 wake_up(&fs_info->async_submit_wait);
1144
1145         if (async_cow->inode)
1146                 submit_compressed_extents(async_cow->inode, async_cow);
1147 }
1148
1149 static noinline void async_cow_free(struct btrfs_work *work)
1150 {
1151         struct async_cow *async_cow;
1152         async_cow = container_of(work, struct async_cow, work);
1153         if (async_cow->inode)
1154                 btrfs_add_delayed_iput(async_cow->inode);
1155         kfree(async_cow);
1156 }
1157
1158 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1159                                 u64 start, u64 end, int *page_started,
1160                                 unsigned long *nr_written)
1161 {
1162         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1163         struct async_cow *async_cow;
1164         struct btrfs_root *root = BTRFS_I(inode)->root;
1165         unsigned long nr_pages;
1166         u64 cur_end;
1167         int limit = 10 * SZ_1M;
1168
1169         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1170                          1, 0, NULL, GFP_NOFS);
1171         while (start < end) {
1172                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1173                 BUG_ON(!async_cow); /* -ENOMEM */
1174                 async_cow->inode = igrab(inode);
1175                 async_cow->root = root;
1176                 async_cow->locked_page = locked_page;
1177                 async_cow->start = start;
1178
1179                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1180                     !btrfs_test_opt(fs_info, FORCE_COMPRESS))
1181                         cur_end = end;
1182                 else
1183                         cur_end = min(end, start + SZ_512K - 1);
1184
1185                 async_cow->end = cur_end;
1186                 INIT_LIST_HEAD(&async_cow->extents);
1187
1188                 btrfs_init_work(&async_cow->work,
1189                                 btrfs_delalloc_helper,
1190                                 async_cow_start, async_cow_submit,
1191                                 async_cow_free);
1192
1193                 nr_pages = (cur_end - start + PAGE_SIZE) >>
1194                         PAGE_SHIFT;
1195                 atomic_add(nr_pages, &fs_info->async_delalloc_pages);
1196
1197                 btrfs_queue_work(fs_info->delalloc_workers, &async_cow->work);
1198
1199                 if (atomic_read(&fs_info->async_delalloc_pages) > limit) {
1200                         wait_event(fs_info->async_submit_wait,
1201                                    (atomic_read(&fs_info->async_delalloc_pages) <
1202                                     limit));
1203                 }
1204
1205                 while (atomic_read(&fs_info->async_submit_draining) &&
1206                        atomic_read(&fs_info->async_delalloc_pages)) {
1207                         wait_event(fs_info->async_submit_wait,
1208                                    (atomic_read(&fs_info->async_delalloc_pages) ==
1209                                     0));
1210                 }
1211
1212                 *nr_written += nr_pages;
1213                 start = cur_end + 1;
1214         }
1215         *page_started = 1;
1216         return 0;
1217 }
1218
1219 static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info,
1220                                         u64 bytenr, u64 num_bytes)
1221 {
1222         int ret;
1223         struct btrfs_ordered_sum *sums;
1224         LIST_HEAD(list);
1225
1226         ret = btrfs_lookup_csums_range(fs_info->csum_root, bytenr,
1227                                        bytenr + num_bytes - 1, &list, 0);
1228         if (ret == 0 && list_empty(&list))
1229                 return 0;
1230
1231         while (!list_empty(&list)) {
1232                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1233                 list_del(&sums->list);
1234                 kfree(sums);
1235         }
1236         return 1;
1237 }
1238
1239 /*
1240  * when nowcow writeback call back.  This checks for snapshots or COW copies
1241  * of the extents that exist in the file, and COWs the file as required.
1242  *
1243  * If no cow copies or snapshots exist, we write directly to the existing
1244  * blocks on disk
1245  */
1246 static noinline int run_delalloc_nocow(struct inode *inode,
1247                                        struct page *locked_page,
1248                               u64 start, u64 end, int *page_started, int force,
1249                               unsigned long *nr_written)
1250 {
1251         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1252         struct btrfs_root *root = BTRFS_I(inode)->root;
1253         struct btrfs_trans_handle *trans;
1254         struct extent_buffer *leaf;
1255         struct btrfs_path *path;
1256         struct btrfs_file_extent_item *fi;
1257         struct btrfs_key found_key;
1258         u64 cow_start;
1259         u64 cur_offset;
1260         u64 extent_end;
1261         u64 extent_offset;
1262         u64 disk_bytenr;
1263         u64 num_bytes;
1264         u64 disk_num_bytes;
1265         u64 ram_bytes;
1266         int extent_type;
1267         int ret, err;
1268         int type;
1269         int nocow;
1270         int check_prev = 1;
1271         bool nolock;
1272         u64 ino = btrfs_ino(inode);
1273
1274         path = btrfs_alloc_path();
1275         if (!path) {
1276                 extent_clear_unlock_delalloc(inode, start, end, end,
1277                                              locked_page,
1278                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1279                                              EXTENT_DO_ACCOUNTING |
1280                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1281                                              PAGE_CLEAR_DIRTY |
1282                                              PAGE_SET_WRITEBACK |
1283                                              PAGE_END_WRITEBACK);
1284                 return -ENOMEM;
1285         }
1286
1287         nolock = btrfs_is_free_space_inode(inode);
1288
1289         if (nolock)
1290                 trans = btrfs_join_transaction_nolock(root);
1291         else
1292                 trans = btrfs_join_transaction(root);
1293
1294         if (IS_ERR(trans)) {
1295                 extent_clear_unlock_delalloc(inode, start, end, end,
1296                                              locked_page,
1297                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1298                                              EXTENT_DO_ACCOUNTING |
1299                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1300                                              PAGE_CLEAR_DIRTY |
1301                                              PAGE_SET_WRITEBACK |
1302                                              PAGE_END_WRITEBACK);
1303                 btrfs_free_path(path);
1304                 return PTR_ERR(trans);
1305         }
1306
1307         trans->block_rsv = &fs_info->delalloc_block_rsv;
1308
1309         cow_start = (u64)-1;
1310         cur_offset = start;
1311         while (1) {
1312                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1313                                                cur_offset, 0);
1314                 if (ret < 0)
1315                         goto error;
1316                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1317                         leaf = path->nodes[0];
1318                         btrfs_item_key_to_cpu(leaf, &found_key,
1319                                               path->slots[0] - 1);
1320                         if (found_key.objectid == ino &&
1321                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1322                                 path->slots[0]--;
1323                 }
1324                 check_prev = 0;
1325 next_slot:
1326                 leaf = path->nodes[0];
1327                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1328                         ret = btrfs_next_leaf(root, path);
1329                         if (ret < 0)
1330                                 goto error;
1331                         if (ret > 0)
1332                                 break;
1333                         leaf = path->nodes[0];
1334                 }
1335
1336                 nocow = 0;
1337                 disk_bytenr = 0;
1338                 num_bytes = 0;
1339                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1340
1341                 if (found_key.objectid > ino)
1342                         break;
1343                 if (WARN_ON_ONCE(found_key.objectid < ino) ||
1344                     found_key.type < BTRFS_EXTENT_DATA_KEY) {
1345                         path->slots[0]++;
1346                         goto next_slot;
1347                 }
1348                 if (found_key.type > BTRFS_EXTENT_DATA_KEY ||
1349                     found_key.offset > end)
1350                         break;
1351
1352                 if (found_key.offset > cur_offset) {
1353                         extent_end = found_key.offset;
1354                         extent_type = 0;
1355                         goto out_check;
1356                 }
1357
1358                 fi = btrfs_item_ptr(leaf, path->slots[0],
1359                                     struct btrfs_file_extent_item);
1360                 extent_type = btrfs_file_extent_type(leaf, fi);
1361
1362                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1363                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1364                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1365                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1366                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1367                         extent_end = found_key.offset +
1368                                 btrfs_file_extent_num_bytes(leaf, fi);
1369                         disk_num_bytes =
1370                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1371                         if (extent_end <= start) {
1372                                 path->slots[0]++;
1373                                 goto next_slot;
1374                         }
1375                         if (disk_bytenr == 0)
1376                                 goto out_check;
1377                         if (btrfs_file_extent_compression(leaf, fi) ||
1378                             btrfs_file_extent_encryption(leaf, fi) ||
1379                             btrfs_file_extent_other_encoding(leaf, fi))
1380                                 goto out_check;
1381                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1382                                 goto out_check;
1383                         if (btrfs_extent_readonly(fs_info, disk_bytenr))
1384                                 goto out_check;
1385                         if (btrfs_cross_ref_exist(trans, root, ino,
1386                                                   found_key.offset -
1387                                                   extent_offset, disk_bytenr))
1388                                 goto out_check;
1389                         disk_bytenr += extent_offset;
1390                         disk_bytenr += cur_offset - found_key.offset;
1391                         num_bytes = min(end + 1, extent_end) - cur_offset;
1392                         /*
1393                          * if there are pending snapshots for this root,
1394                          * we fall into common COW way.
1395                          */
1396                         if (!nolock) {
1397                                 err = btrfs_start_write_no_snapshoting(root);
1398                                 if (!err)
1399                                         goto out_check;
1400                         }
1401                         /*
1402                          * force cow if csum exists in the range.
1403                          * this ensure that csum for a given extent are
1404                          * either valid or do not exist.
1405                          */
1406                         if (csum_exist_in_range(fs_info, disk_bytenr,
1407                                                 num_bytes))
1408                                 goto out_check;
1409                         if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr))
1410                                 goto out_check;
1411                         nocow = 1;
1412                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1413                         extent_end = found_key.offset +
1414                                 btrfs_file_extent_inline_len(leaf,
1415                                                      path->slots[0], fi);
1416                         extent_end = ALIGN(extent_end,
1417                                            fs_info->sectorsize);
1418                 } else {
1419                         BUG_ON(1);
1420                 }
1421 out_check:
1422                 if (extent_end <= start) {
1423                         path->slots[0]++;
1424                         if (!nolock && nocow)
1425                                 btrfs_end_write_no_snapshoting(root);
1426                         if (nocow)
1427                                 btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1428                         goto next_slot;
1429                 }
1430                 if (!nocow) {
1431                         if (cow_start == (u64)-1)
1432                                 cow_start = cur_offset;
1433                         cur_offset = extent_end;
1434                         if (cur_offset > end)
1435                                 break;
1436                         path->slots[0]++;
1437                         goto next_slot;
1438                 }
1439
1440                 btrfs_release_path(path);
1441                 if (cow_start != (u64)-1) {
1442                         ret = cow_file_range(inode, locked_page,
1443                                              cow_start, found_key.offset - 1,
1444                                              end, page_started, nr_written, 1,
1445                                              NULL);
1446                         if (ret) {
1447                                 if (!nolock && nocow)
1448                                         btrfs_end_write_no_snapshoting(root);
1449                                 if (nocow)
1450                                         btrfs_dec_nocow_writers(fs_info,
1451                                                                 disk_bytenr);
1452                                 goto error;
1453                         }
1454                         cow_start = (u64)-1;
1455                 }
1456
1457                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1458                         struct extent_map *em;
1459                         struct extent_map_tree *em_tree;
1460                         em_tree = &BTRFS_I(inode)->extent_tree;
1461                         em = alloc_extent_map();
1462                         BUG_ON(!em); /* -ENOMEM */
1463                         em->start = cur_offset;
1464                         em->orig_start = found_key.offset - extent_offset;
1465                         em->len = num_bytes;
1466                         em->block_len = num_bytes;
1467                         em->block_start = disk_bytenr;
1468                         em->orig_block_len = disk_num_bytes;
1469                         em->ram_bytes = ram_bytes;
1470                         em->bdev = fs_info->fs_devices->latest_bdev;
1471                         em->mod_start = em->start;
1472                         em->mod_len = em->len;
1473                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1474                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1475                         em->generation = -1;
1476                         while (1) {
1477                                 write_lock(&em_tree->lock);
1478                                 ret = add_extent_mapping(em_tree, em, 1);
1479                                 write_unlock(&em_tree->lock);
1480                                 if (ret != -EEXIST) {
1481                                         free_extent_map(em);
1482                                         break;
1483                                 }
1484                                 btrfs_drop_extent_cache(inode, em->start,
1485                                                 em->start + em->len - 1, 0);
1486                         }
1487                         type = BTRFS_ORDERED_PREALLOC;
1488                 } else {
1489                         type = BTRFS_ORDERED_NOCOW;
1490                 }
1491
1492                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1493                                                num_bytes, num_bytes, type);
1494                 if (nocow)
1495                         btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1496                 BUG_ON(ret); /* -ENOMEM */
1497
1498                 if (root->root_key.objectid ==
1499                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1500                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1501                                                       num_bytes);
1502                         if (ret) {
1503                                 if (!nolock && nocow)
1504                                         btrfs_end_write_no_snapshoting(root);
1505                                 goto error;
1506                         }
1507                 }
1508
1509                 extent_clear_unlock_delalloc(inode, cur_offset,
1510                                              cur_offset + num_bytes - 1, end,
1511                                              locked_page, EXTENT_LOCKED |
1512                                              EXTENT_DELALLOC |
1513                                              EXTENT_CLEAR_DATA_RESV,
1514                                              PAGE_UNLOCK | PAGE_SET_PRIVATE2);
1515
1516                 if (!nolock && nocow)
1517                         btrfs_end_write_no_snapshoting(root);
1518                 cur_offset = extent_end;
1519                 if (cur_offset > end)
1520                         break;
1521         }
1522         btrfs_release_path(path);
1523
1524         if (cur_offset <= end && cow_start == (u64)-1) {
1525                 cow_start = cur_offset;
1526                 cur_offset = end;
1527         }
1528
1529         if (cow_start != (u64)-1) {
1530                 ret = cow_file_range(inode, locked_page, cow_start, end, end,
1531                                      page_started, nr_written, 1, NULL);
1532                 if (ret)
1533                         goto error;
1534         }
1535
1536 error:
1537         err = btrfs_end_transaction(trans, root);
1538         if (!ret)
1539                 ret = err;
1540
1541         if (ret && cur_offset < end)
1542                 extent_clear_unlock_delalloc(inode, cur_offset, end, end,
1543                                              locked_page, EXTENT_LOCKED |
1544                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1545                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1546                                              PAGE_CLEAR_DIRTY |
1547                                              PAGE_SET_WRITEBACK |
1548                                              PAGE_END_WRITEBACK);
1549         btrfs_free_path(path);
1550         return ret;
1551 }
1552
1553 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1554 {
1555
1556         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1557             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1558                 return 0;
1559
1560         /*
1561          * @defrag_bytes is a hint value, no spinlock held here,
1562          * if is not zero, it means the file is defragging.
1563          * Force cow if given extent needs to be defragged.
1564          */
1565         if (BTRFS_I(inode)->defrag_bytes &&
1566             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1567                            EXTENT_DEFRAG, 0, NULL))
1568                 return 1;
1569
1570         return 0;
1571 }
1572
1573 /*
1574  * extent_io.c call back to do delayed allocation processing
1575  */
1576 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1577                               u64 start, u64 end, int *page_started,
1578                               unsigned long *nr_written)
1579 {
1580         int ret;
1581         int force_cow = need_force_cow(inode, start, end);
1582
1583         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1584                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1585                                          page_started, 1, nr_written);
1586         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1587                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1588                                          page_started, 0, nr_written);
1589         } else if (!inode_need_compress(inode)) {
1590                 ret = cow_file_range(inode, locked_page, start, end, end,
1591                                       page_started, nr_written, 1, NULL);
1592         } else {
1593                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1594                         &BTRFS_I(inode)->runtime_flags);
1595                 ret = cow_file_range_async(inode, locked_page, start, end,
1596                                            page_started, nr_written);
1597         }
1598         return ret;
1599 }
1600
1601 static void btrfs_split_extent_hook(struct inode *inode,
1602                                     struct extent_state *orig, u64 split)
1603 {
1604         u64 size;
1605
1606         /* not delalloc, ignore it */
1607         if (!(orig->state & EXTENT_DELALLOC))
1608                 return;
1609
1610         size = orig->end - orig->start + 1;
1611         if (size > BTRFS_MAX_EXTENT_SIZE) {
1612                 u64 num_extents;
1613                 u64 new_size;
1614
1615                 /*
1616                  * See the explanation in btrfs_merge_extent_hook, the same
1617                  * applies here, just in reverse.
1618                  */
1619                 new_size = orig->end - split + 1;
1620                 num_extents = div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1621                                         BTRFS_MAX_EXTENT_SIZE);
1622                 new_size = split - orig->start;
1623                 num_extents += div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1624                                         BTRFS_MAX_EXTENT_SIZE);
1625                 if (div64_u64(size + BTRFS_MAX_EXTENT_SIZE - 1,
1626                               BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1627                         return;
1628         }
1629
1630         spin_lock(&BTRFS_I(inode)->lock);
1631         BTRFS_I(inode)->outstanding_extents++;
1632         spin_unlock(&BTRFS_I(inode)->lock);
1633 }
1634
1635 /*
1636  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1637  * extents so we can keep track of new extents that are just merged onto old
1638  * extents, such as when we are doing sequential writes, so we can properly
1639  * account for the metadata space we'll need.
1640  */
1641 static void btrfs_merge_extent_hook(struct inode *inode,
1642                                     struct extent_state *new,
1643                                     struct extent_state *other)
1644 {
1645         u64 new_size, old_size;
1646         u64 num_extents;
1647
1648         /* not delalloc, ignore it */
1649         if (!(other->state & EXTENT_DELALLOC))
1650                 return;
1651
1652         if (new->start > other->start)
1653                 new_size = new->end - other->start + 1;
1654         else
1655                 new_size = other->end - new->start + 1;
1656
1657         /* we're not bigger than the max, unreserve the space and go */
1658         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1659                 spin_lock(&BTRFS_I(inode)->lock);
1660                 BTRFS_I(inode)->outstanding_extents--;
1661                 spin_unlock(&BTRFS_I(inode)->lock);
1662                 return;
1663         }
1664
1665         /*
1666          * We have to add up either side to figure out how many extents were
1667          * accounted for before we merged into one big extent.  If the number of
1668          * extents we accounted for is <= the amount we need for the new range
1669          * then we can return, otherwise drop.  Think of it like this
1670          *
1671          * [ 4k][MAX_SIZE]
1672          *
1673          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1674          * need 2 outstanding extents, on one side we have 1 and the other side
1675          * we have 1 so they are == and we can return.  But in this case
1676          *
1677          * [MAX_SIZE+4k][MAX_SIZE+4k]
1678          *
1679          * Each range on their own accounts for 2 extents, but merged together
1680          * they are only 3 extents worth of accounting, so we need to drop in
1681          * this case.
1682          */
1683         old_size = other->end - other->start + 1;
1684         num_extents = div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1685                                 BTRFS_MAX_EXTENT_SIZE);
1686         old_size = new->end - new->start + 1;
1687         num_extents += div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1688                                  BTRFS_MAX_EXTENT_SIZE);
1689
1690         if (div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1691                       BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1692                 return;
1693
1694         spin_lock(&BTRFS_I(inode)->lock);
1695         BTRFS_I(inode)->outstanding_extents--;
1696         spin_unlock(&BTRFS_I(inode)->lock);
1697 }
1698
1699 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1700                                       struct inode *inode)
1701 {
1702         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1703
1704         spin_lock(&root->delalloc_lock);
1705         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1706                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1707                               &root->delalloc_inodes);
1708                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1709                         &BTRFS_I(inode)->runtime_flags);
1710                 root->nr_delalloc_inodes++;
1711                 if (root->nr_delalloc_inodes == 1) {
1712                         spin_lock(&fs_info->delalloc_root_lock);
1713                         BUG_ON(!list_empty(&root->delalloc_root));
1714                         list_add_tail(&root->delalloc_root,
1715                                       &fs_info->delalloc_roots);
1716                         spin_unlock(&fs_info->delalloc_root_lock);
1717                 }
1718         }
1719         spin_unlock(&root->delalloc_lock);
1720 }
1721
1722 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1723                                      struct inode *inode)
1724 {
1725         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1726
1727         spin_lock(&root->delalloc_lock);
1728         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1729                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1730                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1731                           &BTRFS_I(inode)->runtime_flags);
1732                 root->nr_delalloc_inodes--;
1733                 if (!root->nr_delalloc_inodes) {
1734                         spin_lock(&fs_info->delalloc_root_lock);
1735                         BUG_ON(list_empty(&root->delalloc_root));
1736                         list_del_init(&root->delalloc_root);
1737                         spin_unlock(&fs_info->delalloc_root_lock);
1738                 }
1739         }
1740         spin_unlock(&root->delalloc_lock);
1741 }
1742
1743 /*
1744  * extent_io.c set_bit_hook, used to track delayed allocation
1745  * bytes in this file, and to maintain the list of inodes that
1746  * have pending delalloc work to be done.
1747  */
1748 static void btrfs_set_bit_hook(struct inode *inode,
1749                                struct extent_state *state, unsigned *bits)
1750 {
1751
1752         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1753
1754         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1755                 WARN_ON(1);
1756         /*
1757          * set_bit and clear bit hooks normally require _irqsave/restore
1758          * but in this case, we are only testing for the DELALLOC
1759          * bit, which is only set or cleared with irqs on
1760          */
1761         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1762                 struct btrfs_root *root = BTRFS_I(inode)->root;
1763                 u64 len = state->end + 1 - state->start;
1764                 bool do_list = !btrfs_is_free_space_inode(inode);
1765
1766                 if (*bits & EXTENT_FIRST_DELALLOC) {
1767                         *bits &= ~EXTENT_FIRST_DELALLOC;
1768                 } else {
1769                         spin_lock(&BTRFS_I(inode)->lock);
1770                         BTRFS_I(inode)->outstanding_extents++;
1771                         spin_unlock(&BTRFS_I(inode)->lock);
1772                 }
1773
1774                 /* For sanity tests */
1775                 if (btrfs_is_testing(fs_info))
1776                         return;
1777
1778                 __percpu_counter_add(&fs_info->delalloc_bytes, len,
1779                                      fs_info->delalloc_batch);
1780                 spin_lock(&BTRFS_I(inode)->lock);
1781                 BTRFS_I(inode)->delalloc_bytes += len;
1782                 if (*bits & EXTENT_DEFRAG)
1783                         BTRFS_I(inode)->defrag_bytes += len;
1784                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1785                                          &BTRFS_I(inode)->runtime_flags))
1786                         btrfs_add_delalloc_inodes(root, inode);
1787                 spin_unlock(&BTRFS_I(inode)->lock);
1788         }
1789 }
1790
1791 /*
1792  * extent_io.c clear_bit_hook, see set_bit_hook for why
1793  */
1794 static void btrfs_clear_bit_hook(struct inode *inode,
1795                                  struct extent_state *state,
1796                                  unsigned *bits)
1797 {
1798         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1799         u64 len = state->end + 1 - state->start;
1800         u64 num_extents = div64_u64(len + BTRFS_MAX_EXTENT_SIZE -1,
1801                                     BTRFS_MAX_EXTENT_SIZE);
1802
1803         spin_lock(&BTRFS_I(inode)->lock);
1804         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))
1805                 BTRFS_I(inode)->defrag_bytes -= len;
1806         spin_unlock(&BTRFS_I(inode)->lock);
1807
1808         /*
1809          * set_bit and clear bit hooks normally require _irqsave/restore
1810          * but in this case, we are only testing for the DELALLOC
1811          * bit, which is only set or cleared with irqs on
1812          */
1813         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1814                 struct btrfs_root *root = BTRFS_I(inode)->root;
1815                 bool do_list = !btrfs_is_free_space_inode(inode);
1816
1817                 if (*bits & EXTENT_FIRST_DELALLOC) {
1818                         *bits &= ~EXTENT_FIRST_DELALLOC;
1819                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1820                         spin_lock(&BTRFS_I(inode)->lock);
1821                         BTRFS_I(inode)->outstanding_extents -= num_extents;
1822                         spin_unlock(&BTRFS_I(inode)->lock);
1823                 }
1824
1825                 /*
1826                  * We don't reserve metadata space for space cache inodes so we
1827                  * don't need to call dellalloc_release_metadata if there is an
1828                  * error.
1829                  */
1830                 if (*bits & EXTENT_DO_ACCOUNTING &&
1831                     root != fs_info->tree_root)
1832                         btrfs_delalloc_release_metadata(inode, len);
1833
1834                 /* For sanity tests. */
1835                 if (btrfs_is_testing(fs_info))
1836                         return;
1837
1838                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1839                     && do_list && !(state->state & EXTENT_NORESERVE)
1840                     && (*bits & (EXTENT_DO_ACCOUNTING |
1841                     EXTENT_CLEAR_DATA_RESV)))
1842                         btrfs_free_reserved_data_space_noquota(inode,
1843                                         state->start, len);
1844
1845                 __percpu_counter_add(&fs_info->delalloc_bytes, -len,
1846                                      fs_info->delalloc_batch);
1847                 spin_lock(&BTRFS_I(inode)->lock);
1848                 BTRFS_I(inode)->delalloc_bytes -= len;
1849                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1850                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1851                              &BTRFS_I(inode)->runtime_flags))
1852                         btrfs_del_delalloc_inode(root, inode);
1853                 spin_unlock(&BTRFS_I(inode)->lock);
1854         }
1855 }
1856
1857 /*
1858  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1859  * we don't create bios that span stripes or chunks
1860  *
1861  * return 1 if page cannot be merged to bio
1862  * return 0 if page can be merged to bio
1863  * return error otherwise
1864  */
1865 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1866                          size_t size, struct bio *bio,
1867                          unsigned long bio_flags)
1868 {
1869         struct inode *inode = page->mapping->host;
1870         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1871         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1872         u64 length = 0;
1873         u64 map_length;
1874         int ret;
1875
1876         if (bio_flags & EXTENT_BIO_COMPRESSED)
1877                 return 0;
1878
1879         length = bio->bi_iter.bi_size;
1880         map_length = length;
1881         ret = btrfs_map_block(fs_info, btrfs_op(bio), logical, &map_length,
1882                               NULL, 0);
1883         if (ret < 0)
1884                 return ret;
1885         if (map_length < length + size)
1886                 return 1;
1887         return 0;
1888 }
1889
1890 /*
1891  * in order to insert checksums into the metadata in large chunks,
1892  * we wait until bio submission time.   All the pages in the bio are
1893  * checksummed and sums are attached onto the ordered extent record.
1894  *
1895  * At IO completion time the cums attached on the ordered extent record
1896  * are inserted into the btree
1897  */
1898 static int __btrfs_submit_bio_start(struct inode *inode, struct bio *bio,
1899                                     int mirror_num, unsigned long bio_flags,
1900                                     u64 bio_offset)
1901 {
1902         int ret = 0;
1903
1904         ret = btrfs_csum_one_bio(inode, bio, 0, 0);
1905         BUG_ON(ret); /* -ENOMEM */
1906         return 0;
1907 }
1908
1909 /*
1910  * in order to insert checksums into the metadata in large chunks,
1911  * we wait until bio submission time.   All the pages in the bio are
1912  * checksummed and sums are attached onto the ordered extent record.
1913  *
1914  * At IO completion time the cums attached on the ordered extent record
1915  * are inserted into the btree
1916  */
1917 static int __btrfs_submit_bio_done(struct inode *inode, struct bio *bio,
1918                           int mirror_num, unsigned long bio_flags,
1919                           u64 bio_offset)
1920 {
1921         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1922         int ret;
1923
1924         ret = btrfs_map_bio(fs_info, bio, mirror_num, 1);
1925         if (ret) {
1926                 bio->bi_error = ret;
1927                 bio_endio(bio);
1928         }
1929         return ret;
1930 }
1931
1932 /*
1933  * extent_io.c submission hook. This does the right thing for csum calculation
1934  * on write, or reading the csums from the tree before a read
1935  */
1936 static int btrfs_submit_bio_hook(struct inode *inode, struct bio *bio,
1937                           int mirror_num, unsigned long bio_flags,
1938                           u64 bio_offset)
1939 {
1940         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1941         struct btrfs_root *root = BTRFS_I(inode)->root;
1942         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
1943         int ret = 0;
1944         int skip_sum;
1945         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1946
1947         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1948
1949         if (btrfs_is_free_space_inode(inode))
1950                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
1951
1952         if (bio_op(bio) != REQ_OP_WRITE) {
1953                 ret = btrfs_bio_wq_end_io(fs_info, bio, metadata);
1954                 if (ret)
1955                         goto out;
1956
1957                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1958                         ret = btrfs_submit_compressed_read(inode, bio,
1959                                                            mirror_num,
1960                                                            bio_flags);
1961                         goto out;
1962                 } else if (!skip_sum) {
1963                         ret = btrfs_lookup_bio_sums(inode, bio, NULL);
1964                         if (ret)
1965                                 goto out;
1966                 }
1967                 goto mapit;
1968         } else if (async && !skip_sum) {
1969                 /* csum items have already been cloned */
1970                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1971                         goto mapit;
1972                 /* we're doing a write, do the async checksumming */
1973                 ret = btrfs_wq_submit_bio(fs_info, inode, bio, mirror_num,
1974                                           bio_flags, bio_offset,
1975                                           __btrfs_submit_bio_start,
1976                                           __btrfs_submit_bio_done);
1977                 goto out;
1978         } else if (!skip_sum) {
1979                 ret = btrfs_csum_one_bio(inode, bio, 0, 0);
1980                 if (ret)
1981                         goto out;
1982         }
1983
1984 mapit:
1985         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
1986
1987 out:
1988         if (ret < 0) {
1989                 bio->bi_error = ret;
1990                 bio_endio(bio);
1991         }
1992         return ret;
1993 }
1994
1995 /*
1996  * given a list of ordered sums record them in the inode.  This happens
1997  * at IO completion time based on sums calculated at bio submission time.
1998  */
1999 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
2000                              struct inode *inode, u64 file_offset,
2001                              struct list_head *list)
2002 {
2003         struct btrfs_ordered_sum *sum;
2004
2005         list_for_each_entry(sum, list, list) {
2006                 trans->adding_csums = 1;
2007                 btrfs_csum_file_blocks(trans,
2008                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
2009                 trans->adding_csums = 0;
2010         }
2011         return 0;
2012 }
2013
2014 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
2015                               struct extent_state **cached_state, int dedupe)
2016 {
2017         WARN_ON((end & (PAGE_SIZE - 1)) == 0);
2018         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
2019                                    cached_state);
2020 }
2021
2022 /* see btrfs_writepage_start_hook for details on why this is required */
2023 struct btrfs_writepage_fixup {
2024         struct page *page;
2025         struct btrfs_work work;
2026 };
2027
2028 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
2029 {
2030         struct btrfs_writepage_fixup *fixup;
2031         struct btrfs_ordered_extent *ordered;
2032         struct extent_state *cached_state = NULL;
2033         struct page *page;
2034         struct inode *inode;
2035         u64 page_start;
2036         u64 page_end;
2037         int ret;
2038
2039         fixup = container_of(work, struct btrfs_writepage_fixup, work);
2040         page = fixup->page;
2041 again:
2042         lock_page(page);
2043         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
2044                 ClearPageChecked(page);
2045                 goto out_page;
2046         }
2047
2048         inode = page->mapping->host;
2049         page_start = page_offset(page);
2050         page_end = page_offset(page) + PAGE_SIZE - 1;
2051
2052         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
2053                          &cached_state);
2054
2055         /* already ordered? We're done */
2056         if (PagePrivate2(page))
2057                 goto out;
2058
2059         ordered = btrfs_lookup_ordered_range(inode, page_start,
2060                                         PAGE_SIZE);
2061         if (ordered) {
2062                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
2063                                      page_end, &cached_state, GFP_NOFS);
2064                 unlock_page(page);
2065                 btrfs_start_ordered_extent(inode, ordered, 1);
2066                 btrfs_put_ordered_extent(ordered);
2067                 goto again;
2068         }
2069
2070         ret = btrfs_delalloc_reserve_space(inode, page_start,
2071                                            PAGE_SIZE);
2072         if (ret) {
2073                 mapping_set_error(page->mapping, ret);
2074                 end_extent_writepage(page, ret, page_start, page_end);
2075                 ClearPageChecked(page);
2076                 goto out;
2077          }
2078
2079         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state,
2080                                   0);
2081         ClearPageChecked(page);
2082         set_page_dirty(page);
2083 out:
2084         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
2085                              &cached_state, GFP_NOFS);
2086 out_page:
2087         unlock_page(page);
2088         put_page(page);
2089         kfree(fixup);
2090 }
2091
2092 /*
2093  * There are a few paths in the higher layers of the kernel that directly
2094  * set the page dirty bit without asking the filesystem if it is a
2095  * good idea.  This causes problems because we want to make sure COW
2096  * properly happens and the data=ordered rules are followed.
2097  *
2098  * In our case any range that doesn't have the ORDERED bit set
2099  * hasn't been properly setup for IO.  We kick off an async process
2100  * to fix it up.  The async helper will wait for ordered extents, set
2101  * the delalloc bit and make it safe to write the page.
2102  */
2103 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
2104 {
2105         struct inode *inode = page->mapping->host;
2106         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2107         struct btrfs_writepage_fixup *fixup;
2108
2109         /* this page is properly in the ordered list */
2110         if (TestClearPagePrivate2(page))
2111                 return 0;
2112
2113         if (PageChecked(page))
2114                 return -EAGAIN;
2115
2116         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2117         if (!fixup)
2118                 return -EAGAIN;
2119
2120         SetPageChecked(page);
2121         get_page(page);
2122         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
2123                         btrfs_writepage_fixup_worker, NULL, NULL);
2124         fixup->page = page;
2125         btrfs_queue_work(fs_info->fixup_workers, &fixup->work);
2126         return -EBUSY;
2127 }
2128
2129 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2130                                        struct inode *inode, u64 file_pos,
2131                                        u64 disk_bytenr, u64 disk_num_bytes,
2132                                        u64 num_bytes, u64 ram_bytes,
2133                                        u8 compression, u8 encryption,
2134                                        u16 other_encoding, int extent_type)
2135 {
2136         struct btrfs_root *root = BTRFS_I(inode)->root;
2137         struct btrfs_file_extent_item *fi;
2138         struct btrfs_path *path;
2139         struct extent_buffer *leaf;
2140         struct btrfs_key ins;
2141         int extent_inserted = 0;
2142         int ret;
2143
2144         path = btrfs_alloc_path();
2145         if (!path)
2146                 return -ENOMEM;
2147
2148         /*
2149          * we may be replacing one extent in the tree with another.
2150          * The new extent is pinned in the extent map, and we don't want
2151          * to drop it from the cache until it is completely in the btree.
2152          *
2153          * So, tell btrfs_drop_extents to leave this extent in the cache.
2154          * the caller is expected to unpin it and allow it to be merged
2155          * with the others.
2156          */
2157         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2158                                    file_pos + num_bytes, NULL, 0,
2159                                    1, sizeof(*fi), &extent_inserted);
2160         if (ret)
2161                 goto out;
2162
2163         if (!extent_inserted) {
2164                 ins.objectid = btrfs_ino(inode);
2165                 ins.offset = file_pos;
2166                 ins.type = BTRFS_EXTENT_DATA_KEY;
2167
2168                 path->leave_spinning = 1;
2169                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2170                                               sizeof(*fi));
2171                 if (ret)
2172                         goto out;
2173         }
2174         leaf = path->nodes[0];
2175         fi = btrfs_item_ptr(leaf, path->slots[0],
2176                             struct btrfs_file_extent_item);
2177         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2178         btrfs_set_file_extent_type(leaf, fi, extent_type);
2179         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2180         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2181         btrfs_set_file_extent_offset(leaf, fi, 0);
2182         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2183         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2184         btrfs_set_file_extent_compression(leaf, fi, compression);
2185         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2186         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2187
2188         btrfs_mark_buffer_dirty(leaf);
2189         btrfs_release_path(path);
2190
2191         inode_add_bytes(inode, num_bytes);
2192
2193         ins.objectid = disk_bytenr;
2194         ins.offset = disk_num_bytes;
2195         ins.type = BTRFS_EXTENT_ITEM_KEY;
2196         ret = btrfs_alloc_reserved_file_extent(trans, root->root_key.objectid,
2197                                                btrfs_ino(inode), file_pos,
2198                                                ram_bytes, &ins);
2199         /*
2200          * Release the reserved range from inode dirty range map, as it is
2201          * already moved into delayed_ref_head
2202          */
2203         btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2204 out:
2205         btrfs_free_path(path);
2206
2207         return ret;
2208 }
2209
2210 /* snapshot-aware defrag */
2211 struct sa_defrag_extent_backref {
2212         struct rb_node node;
2213         struct old_sa_defrag_extent *old;
2214         u64 root_id;
2215         u64 inum;
2216         u64 file_pos;
2217         u64 extent_offset;
2218         u64 num_bytes;
2219         u64 generation;
2220 };
2221
2222 struct old_sa_defrag_extent {
2223         struct list_head list;
2224         struct new_sa_defrag_extent *new;
2225
2226         u64 extent_offset;
2227         u64 bytenr;
2228         u64 offset;
2229         u64 len;
2230         int count;
2231 };
2232
2233 struct new_sa_defrag_extent {
2234         struct rb_root root;
2235         struct list_head head;
2236         struct btrfs_path *path;
2237         struct inode *inode;
2238         u64 file_pos;
2239         u64 len;
2240         u64 bytenr;
2241         u64 disk_len;
2242         u8 compress_type;
2243 };
2244
2245 static int backref_comp(struct sa_defrag_extent_backref *b1,
2246                         struct sa_defrag_extent_backref *b2)
2247 {
2248         if (b1->root_id < b2->root_id)
2249                 return -1;
2250         else if (b1->root_id > b2->root_id)
2251                 return 1;
2252
2253         if (b1->inum < b2->inum)
2254                 return -1;
2255         else if (b1->inum > b2->inum)
2256                 return 1;
2257
2258         if (b1->file_pos < b2->file_pos)
2259                 return -1;
2260         else if (b1->file_pos > b2->file_pos)
2261                 return 1;
2262
2263         /*
2264          * [------------------------------] ===> (a range of space)
2265          *     |<--->|   |<---->| =============> (fs/file tree A)
2266          * |<---------------------------->| ===> (fs/file tree B)
2267          *
2268          * A range of space can refer to two file extents in one tree while
2269          * refer to only one file extent in another tree.
2270          *
2271          * So we may process a disk offset more than one time(two extents in A)
2272          * and locate at the same extent(one extent in B), then insert two same
2273          * backrefs(both refer to the extent in B).
2274          */
2275         return 0;
2276 }
2277
2278 static void backref_insert(struct rb_root *root,
2279                            struct sa_defrag_extent_backref *backref)
2280 {
2281         struct rb_node **p = &root->rb_node;
2282         struct rb_node *parent = NULL;
2283         struct sa_defrag_extent_backref *entry;
2284         int ret;
2285
2286         while (*p) {
2287                 parent = *p;
2288                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2289
2290                 ret = backref_comp(backref, entry);
2291                 if (ret < 0)
2292                         p = &(*p)->rb_left;
2293                 else
2294                         p = &(*p)->rb_right;
2295         }
2296
2297         rb_link_node(&backref->node, parent, p);
2298         rb_insert_color(&backref->node, root);
2299 }
2300
2301 /*
2302  * Note the backref might has changed, and in this case we just return 0.
2303  */
2304 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2305                                        void *ctx)
2306 {
2307         struct btrfs_file_extent_item *extent;
2308         struct old_sa_defrag_extent *old = ctx;
2309         struct new_sa_defrag_extent *new = old->new;
2310         struct btrfs_path *path = new->path;
2311         struct btrfs_key key;
2312         struct btrfs_root *root;
2313         struct sa_defrag_extent_backref *backref;
2314         struct extent_buffer *leaf;
2315         struct inode *inode = new->inode;
2316         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2317         int slot;
2318         int ret;
2319         u64 extent_offset;
2320         u64 num_bytes;
2321
2322         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2323             inum == btrfs_ino(inode))
2324                 return 0;
2325
2326         key.objectid = root_id;
2327         key.type = BTRFS_ROOT_ITEM_KEY;
2328         key.offset = (u64)-1;
2329
2330         root = btrfs_read_fs_root_no_name(fs_info, &key);
2331         if (IS_ERR(root)) {
2332                 if (PTR_ERR(root) == -ENOENT)
2333                         return 0;
2334                 WARN_ON(1);
2335                 btrfs_debug(fs_info, "inum=%llu, offset=%llu, root_id=%llu",
2336                          inum, offset, root_id);
2337                 return PTR_ERR(root);
2338         }
2339
2340         key.objectid = inum;
2341         key.type = BTRFS_EXTENT_DATA_KEY;
2342         if (offset > (u64)-1 << 32)
2343                 key.offset = 0;
2344         else
2345                 key.offset = offset;
2346
2347         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2348         if (WARN_ON(ret < 0))
2349                 return ret;
2350         ret = 0;
2351
2352         while (1) {
2353                 cond_resched();
2354
2355                 leaf = path->nodes[0];
2356                 slot = path->slots[0];
2357
2358                 if (slot >= btrfs_header_nritems(leaf)) {
2359                         ret = btrfs_next_leaf(root, path);
2360                         if (ret < 0) {
2361                                 goto out;
2362                         } else if (ret > 0) {
2363                                 ret = 0;
2364                                 goto out;
2365                         }
2366                         continue;
2367                 }
2368
2369                 path->slots[0]++;
2370
2371                 btrfs_item_key_to_cpu(leaf, &key, slot);
2372
2373                 if (key.objectid > inum)
2374                         goto out;
2375
2376                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2377                         continue;
2378
2379                 extent = btrfs_item_ptr(leaf, slot,
2380                                         struct btrfs_file_extent_item);
2381
2382                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2383                         continue;
2384
2385                 /*
2386                  * 'offset' refers to the exact key.offset,
2387                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2388                  * (key.offset - extent_offset).
2389                  */
2390                 if (key.offset != offset)
2391                         continue;
2392
2393                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2394                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2395
2396                 if (extent_offset >= old->extent_offset + old->offset +
2397                     old->len || extent_offset + num_bytes <=
2398                     old->extent_offset + old->offset)
2399                         continue;
2400                 break;
2401         }
2402
2403         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2404         if (!backref) {
2405                 ret = -ENOENT;
2406                 goto out;
2407         }
2408
2409         backref->root_id = root_id;
2410         backref->inum = inum;
2411         backref->file_pos = offset;
2412         backref->num_bytes = num_bytes;
2413         backref->extent_offset = extent_offset;
2414         backref->generation = btrfs_file_extent_generation(leaf, extent);
2415         backref->old = old;
2416         backref_insert(&new->root, backref);
2417         old->count++;
2418 out:
2419         btrfs_release_path(path);
2420         WARN_ON(ret);
2421         return ret;
2422 }
2423
2424 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2425                                    struct new_sa_defrag_extent *new)
2426 {
2427         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2428         struct old_sa_defrag_extent *old, *tmp;
2429         int ret;
2430
2431         new->path = path;
2432
2433         list_for_each_entry_safe(old, tmp, &new->head, list) {
2434                 ret = iterate_inodes_from_logical(old->bytenr +
2435                                                   old->extent_offset, fs_info,
2436                                                   path, record_one_backref,
2437                                                   old);
2438                 if (ret < 0 && ret != -ENOENT)
2439                         return false;
2440
2441                 /* no backref to be processed for this extent */
2442                 if (!old->count) {
2443                         list_del(&old->list);
2444                         kfree(old);
2445                 }
2446         }
2447
2448         if (list_empty(&new->head))
2449                 return false;
2450
2451         return true;
2452 }
2453
2454 static int relink_is_mergable(struct extent_buffer *leaf,
2455                               struct btrfs_file_extent_item *fi,
2456                               struct new_sa_defrag_extent *new)
2457 {
2458         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2459                 return 0;
2460
2461         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2462                 return 0;
2463
2464         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2465                 return 0;
2466
2467         if (btrfs_file_extent_encryption(leaf, fi) ||
2468             btrfs_file_extent_other_encoding(leaf, fi))
2469                 return 0;
2470
2471         return 1;
2472 }
2473
2474 /*
2475  * Note the backref might has changed, and in this case we just return 0.
2476  */
2477 static noinline int relink_extent_backref(struct btrfs_path *path,
2478                                  struct sa_defrag_extent_backref *prev,
2479                                  struct sa_defrag_extent_backref *backref)
2480 {
2481         struct btrfs_file_extent_item *extent;
2482         struct btrfs_file_extent_item *item;
2483         struct btrfs_ordered_extent *ordered;
2484         struct btrfs_trans_handle *trans;
2485         struct btrfs_root *root;
2486         struct btrfs_key key;
2487         struct extent_buffer *leaf;
2488         struct old_sa_defrag_extent *old = backref->old;
2489         struct new_sa_defrag_extent *new = old->new;
2490         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2491         struct inode *inode;
2492         struct extent_state *cached = NULL;
2493         int ret = 0;
2494         u64 start;
2495         u64 len;
2496         u64 lock_start;
2497         u64 lock_end;
2498         bool merge = false;
2499         int index;
2500
2501         if (prev && prev->root_id == backref->root_id &&
2502             prev->inum == backref->inum &&
2503             prev->file_pos + prev->num_bytes == backref->file_pos)
2504                 merge = true;
2505
2506         /* step 1: get root */
2507         key.objectid = backref->root_id;
2508         key.type = BTRFS_ROOT_ITEM_KEY;
2509         key.offset = (u64)-1;
2510
2511         index = srcu_read_lock(&fs_info->subvol_srcu);
2512
2513         root = btrfs_read_fs_root_no_name(fs_info, &key);
2514         if (IS_ERR(root)) {
2515                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2516                 if (PTR_ERR(root) == -ENOENT)
2517                         return 0;
2518                 return PTR_ERR(root);
2519         }
2520
2521         if (btrfs_root_readonly(root)) {
2522                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2523                 return 0;
2524         }
2525
2526         /* step 2: get inode */
2527         key.objectid = backref->inum;
2528         key.type = BTRFS_INODE_ITEM_KEY;
2529         key.offset = 0;
2530
2531         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2532         if (IS_ERR(inode)) {
2533                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2534                 return 0;
2535         }
2536
2537         srcu_read_unlock(&fs_info->subvol_srcu, index);
2538
2539         /* step 3: relink backref */
2540         lock_start = backref->file_pos;
2541         lock_end = backref->file_pos + backref->num_bytes - 1;
2542         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2543                          &cached);
2544
2545         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2546         if (ordered) {
2547                 btrfs_put_ordered_extent(ordered);
2548                 goto out_unlock;
2549         }
2550
2551         trans = btrfs_join_transaction(root);
2552         if (IS_ERR(trans)) {
2553                 ret = PTR_ERR(trans);
2554                 goto out_unlock;
2555         }
2556
2557         key.objectid = backref->inum;
2558         key.type = BTRFS_EXTENT_DATA_KEY;
2559         key.offset = backref->file_pos;
2560
2561         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2562         if (ret < 0) {
2563                 goto out_free_path;
2564         } else if (ret > 0) {
2565                 ret = 0;
2566                 goto out_free_path;
2567         }
2568
2569         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2570                                 struct btrfs_file_extent_item);
2571
2572         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2573             backref->generation)
2574                 goto out_free_path;
2575
2576         btrfs_release_path(path);
2577
2578         start = backref->file_pos;
2579         if (backref->extent_offset < old->extent_offset + old->offset)
2580                 start += old->extent_offset + old->offset -
2581                          backref->extent_offset;
2582
2583         len = min(backref->extent_offset + backref->num_bytes,
2584                   old->extent_offset + old->offset + old->len);
2585         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2586
2587         ret = btrfs_drop_extents(trans, root, inode, start,
2588                                  start + len, 1);
2589         if (ret)
2590                 goto out_free_path;
2591 again:
2592         key.objectid = btrfs_ino(inode);
2593         key.type = BTRFS_EXTENT_DATA_KEY;
2594         key.offset = start;
2595
2596         path->leave_spinning = 1;
2597         if (merge) {
2598                 struct btrfs_file_extent_item *fi;
2599                 u64 extent_len;
2600                 struct btrfs_key found_key;
2601
2602                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2603                 if (ret < 0)
2604                         goto out_free_path;
2605
2606                 path->slots[0]--;
2607                 leaf = path->nodes[0];
2608                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2609
2610                 fi = btrfs_item_ptr(leaf, path->slots[0],
2611                                     struct btrfs_file_extent_item);
2612                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2613
2614                 if (extent_len + found_key.offset == start &&
2615                     relink_is_mergable(leaf, fi, new)) {
2616                         btrfs_set_file_extent_num_bytes(leaf, fi,
2617                                                         extent_len + len);
2618                         btrfs_mark_buffer_dirty(leaf);
2619                         inode_add_bytes(inode, len);
2620
2621                         ret = 1;
2622                         goto out_free_path;
2623                 } else {
2624                         merge = false;
2625                         btrfs_release_path(path);
2626                         goto again;
2627                 }
2628         }
2629
2630         ret = btrfs_insert_empty_item(trans, root, path, &key,
2631                                         sizeof(*extent));
2632         if (ret) {
2633                 btrfs_abort_transaction(trans, ret);
2634                 goto out_free_path;
2635         }
2636
2637         leaf = path->nodes[0];
2638         item = btrfs_item_ptr(leaf, path->slots[0],
2639                                 struct btrfs_file_extent_item);
2640         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2641         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2642         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2643         btrfs_set_file_extent_num_bytes(leaf, item, len);
2644         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2645         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2646         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2647         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2648         btrfs_set_file_extent_encryption(leaf, item, 0);
2649         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2650
2651         btrfs_mark_buffer_dirty(leaf);
2652         inode_add_bytes(inode, len);
2653         btrfs_release_path(path);
2654
2655         ret = btrfs_inc_extent_ref(trans, fs_info, new->bytenr,
2656                         new->disk_len, 0,
2657                         backref->root_id, backref->inum,
2658                         new->file_pos); /* start - extent_offset */
2659         if (ret) {
2660                 btrfs_abort_transaction(trans, ret);
2661                 goto out_free_path;
2662         }
2663
2664         ret = 1;
2665 out_free_path:
2666         btrfs_release_path(path);
2667         path->leave_spinning = 0;
2668         btrfs_end_transaction(trans, root);
2669 out_unlock:
2670         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2671                              &cached, GFP_NOFS);
2672         iput(inode);
2673         return ret;
2674 }
2675
2676 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2677 {
2678         struct old_sa_defrag_extent *old, *tmp;
2679
2680         if (!new)
2681                 return;
2682
2683         list_for_each_entry_safe(old, tmp, &new->head, list) {
2684                 kfree(old);
2685         }
2686         kfree(new);
2687 }
2688
2689 static void relink_file_extents(struct new_sa_defrag_extent *new)
2690 {
2691         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2692         struct btrfs_path *path;
2693         struct sa_defrag_extent_backref *backref;
2694         struct sa_defrag_extent_backref *prev = NULL;
2695         struct inode *inode;
2696         struct btrfs_root *root;
2697         struct rb_node *node;
2698         int ret;
2699
2700         inode = new->inode;
2701         root = BTRFS_I(inode)->root;
2702
2703         path = btrfs_alloc_path();
2704         if (!path)
2705                 return;
2706
2707         if (!record_extent_backrefs(path, new)) {
2708                 btrfs_free_path(path);
2709                 goto out;
2710         }
2711         btrfs_release_path(path);
2712
2713         while (1) {
2714                 node = rb_first(&new->root);
2715                 if (!node)
2716                         break;
2717                 rb_erase(node, &new->root);
2718
2719                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2720
2721                 ret = relink_extent_backref(path, prev, backref);
2722                 WARN_ON(ret < 0);
2723
2724                 kfree(prev);
2725
2726                 if (ret == 1)
2727                         prev = backref;
2728                 else
2729                         prev = NULL;
2730                 cond_resched();
2731         }
2732         kfree(prev);
2733
2734         btrfs_free_path(path);
2735 out:
2736         free_sa_defrag_extent(new);
2737
2738         atomic_dec(&fs_info->defrag_running);
2739         wake_up(&fs_info->transaction_wait);
2740 }
2741
2742 static struct new_sa_defrag_extent *
2743 record_old_file_extents(struct inode *inode,
2744                         struct btrfs_ordered_extent *ordered)
2745 {
2746         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2747         struct btrfs_root *root = BTRFS_I(inode)->root;
2748         struct btrfs_path *path;
2749         struct btrfs_key key;
2750         struct old_sa_defrag_extent *old;
2751         struct new_sa_defrag_extent *new;
2752         int ret;
2753
2754         new = kmalloc(sizeof(*new), GFP_NOFS);
2755         if (!new)
2756                 return NULL;
2757
2758         new->inode = inode;
2759         new->file_pos = ordered->file_offset;
2760         new->len = ordered->len;
2761         new->bytenr = ordered->start;
2762         new->disk_len = ordered->disk_len;
2763         new->compress_type = ordered->compress_type;
2764         new->root = RB_ROOT;
2765         INIT_LIST_HEAD(&new->head);
2766
2767         path = btrfs_alloc_path();
2768         if (!path)
2769                 goto out_kfree;
2770
2771         key.objectid = btrfs_ino(inode);
2772         key.type = BTRFS_EXTENT_DATA_KEY;
2773         key.offset = new->file_pos;
2774
2775         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2776         if (ret < 0)
2777                 goto out_free_path;
2778         if (ret > 0 && path->slots[0] > 0)
2779                 path->slots[0]--;
2780
2781         /* find out all the old extents for the file range */
2782         while (1) {
2783                 struct btrfs_file_extent_item *extent;
2784                 struct extent_buffer *l;
2785                 int slot;
2786                 u64 num_bytes;
2787                 u64 offset;
2788                 u64 end;
2789                 u64 disk_bytenr;
2790                 u64 extent_offset;
2791
2792                 l = path->nodes[0];
2793                 slot = path->slots[0];
2794
2795                 if (slot >= btrfs_header_nritems(l)) {
2796                         ret = btrfs_next_leaf(root, path);
2797                         if (ret < 0)
2798                                 goto out_free_path;
2799                         else if (ret > 0)
2800                                 break;
2801                         continue;
2802                 }
2803
2804                 btrfs_item_key_to_cpu(l, &key, slot);
2805
2806                 if (key.objectid != btrfs_ino(inode))
2807                         break;
2808                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2809                         break;
2810                 if (key.offset >= new->file_pos + new->len)
2811                         break;
2812
2813                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2814
2815                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2816                 if (key.offset + num_bytes < new->file_pos)
2817                         goto next;
2818
2819                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2820                 if (!disk_bytenr)
2821                         goto next;
2822
2823                 extent_offset = btrfs_file_extent_offset(l, extent);
2824
2825                 old = kmalloc(sizeof(*old), GFP_NOFS);
2826                 if (!old)
2827                         goto out_free_path;
2828
2829                 offset = max(new->file_pos, key.offset);
2830                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2831
2832                 old->bytenr = disk_bytenr;
2833                 old->extent_offset = extent_offset;
2834                 old->offset = offset - key.offset;
2835                 old->len = end - offset;
2836                 old->new = new;
2837                 old->count = 0;
2838                 list_add_tail(&old->list, &new->head);
2839 next:
2840                 path->slots[0]++;
2841                 cond_resched();
2842         }
2843
2844         btrfs_free_path(path);
2845         atomic_inc(&fs_info->defrag_running);
2846
2847         return new;
2848
2849 out_free_path:
2850         btrfs_free_path(path);
2851 out_kfree:
2852         free_sa_defrag_extent(new);
2853         return NULL;
2854 }
2855
2856 static void btrfs_release_delalloc_bytes(struct btrfs_fs_info *fs_info,
2857                                          u64 start, u64 len)
2858 {
2859         struct btrfs_block_group_cache *cache;
2860
2861         cache = btrfs_lookup_block_group(fs_info, start);
2862         ASSERT(cache);
2863
2864         spin_lock(&cache->lock);
2865         cache->delalloc_bytes -= len;
2866         spin_unlock(&cache->lock);
2867
2868         btrfs_put_block_group(cache);
2869 }
2870
2871 /* as ordered data IO finishes, this gets called so we can finish
2872  * an ordered extent if the range of bytes in the file it covers are
2873  * fully written.
2874  */
2875 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2876 {
2877         struct inode *inode = ordered_extent->inode;
2878         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2879         struct btrfs_root *root = BTRFS_I(inode)->root;
2880         struct btrfs_trans_handle *trans = NULL;
2881         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2882         struct extent_state *cached_state = NULL;
2883         struct new_sa_defrag_extent *new = NULL;
2884         int compress_type = 0;
2885         int ret = 0;
2886         u64 logical_len = ordered_extent->len;
2887         bool nolock;
2888         bool truncated = false;
2889
2890         nolock = btrfs_is_free_space_inode(inode);
2891
2892         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2893                 ret = -EIO;
2894                 goto out;
2895         }
2896
2897         btrfs_free_io_failure_record(inode, ordered_extent->file_offset,
2898                                      ordered_extent->file_offset +
2899                                      ordered_extent->len - 1);
2900
2901         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2902                 truncated = true;
2903                 logical_len = ordered_extent->truncated_len;
2904                 /* Truncated the entire extent, don't bother adding */
2905                 if (!logical_len)
2906                         goto out;
2907         }
2908
2909         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2910                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2911
2912                 /*
2913                  * For mwrite(mmap + memset to write) case, we still reserve
2914                  * space for NOCOW range.
2915                  * As NOCOW won't cause a new delayed ref, just free the space
2916                  */
2917                 btrfs_qgroup_free_data(inode, ordered_extent->file_offset,
2918                                        ordered_extent->len);
2919                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2920                 if (nolock)
2921                         trans = btrfs_join_transaction_nolock(root);
2922                 else
2923                         trans = btrfs_join_transaction(root);
2924                 if (IS_ERR(trans)) {
2925                         ret = PTR_ERR(trans);
2926                         trans = NULL;
2927                         goto out;
2928                 }
2929                 trans->block_rsv = &fs_info->delalloc_block_rsv;
2930                 ret = btrfs_update_inode_fallback(trans, root, inode);
2931                 if (ret) /* -ENOMEM or corruption */
2932                         btrfs_abort_transaction(trans, ret);
2933                 goto out;
2934         }
2935
2936         lock_extent_bits(io_tree, ordered_extent->file_offset,
2937                          ordered_extent->file_offset + ordered_extent->len - 1,
2938                          &cached_state);
2939
2940         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2941                         ordered_extent->file_offset + ordered_extent->len - 1,
2942                         EXTENT_DEFRAG, 1, cached_state);
2943         if (ret) {
2944                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2945                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2946                         /* the inode is shared */
2947                         new = record_old_file_extents(inode, ordered_extent);
2948
2949                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2950                         ordered_extent->file_offset + ordered_extent->len - 1,
2951                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2952         }
2953
2954         if (nolock)
2955                 trans = btrfs_join_transaction_nolock(root);
2956         else
2957                 trans = btrfs_join_transaction(root);
2958         if (IS_ERR(trans)) {
2959                 ret = PTR_ERR(trans);
2960                 trans = NULL;
2961                 goto out_unlock;
2962         }
2963
2964         trans->block_rsv = &fs_info->delalloc_block_rsv;
2965
2966         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2967                 compress_type = ordered_extent->compress_type;
2968         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2969                 BUG_ON(compress_type);
2970                 ret = btrfs_mark_extent_written(trans, inode,
2971                                                 ordered_extent->file_offset,
2972                                                 ordered_extent->file_offset +
2973                                                 logical_len);
2974         } else {
2975                 BUG_ON(root == fs_info->tree_root);
2976                 ret = insert_reserved_file_extent(trans, inode,
2977                                                 ordered_extent->file_offset,
2978                                                 ordered_extent->start,
2979                                                 ordered_extent->disk_len,
2980                                                 logical_len, logical_len,
2981                                                 compress_type, 0, 0,
2982                                                 BTRFS_FILE_EXTENT_REG);
2983                 if (!ret)
2984                         btrfs_release_delalloc_bytes(fs_info,
2985                                                      ordered_extent->start,
2986                                                      ordered_extent->disk_len);
2987         }
2988         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2989                            ordered_extent->file_offset, ordered_extent->len,
2990                            trans->transid);
2991         if (ret < 0) {
2992                 btrfs_abort_transaction(trans, ret);
2993                 goto out_unlock;
2994         }
2995
2996         add_pending_csums(trans, inode, ordered_extent->file_offset,
2997                           &ordered_extent->list);
2998
2999         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
3000         ret = btrfs_update_inode_fallback(trans, root, inode);
3001         if (ret) { /* -ENOMEM or corruption */
3002                 btrfs_abort_transaction(trans, ret);
3003                 goto out_unlock;
3004         }
3005         ret = 0;
3006 out_unlock:
3007         unlock_extent_cached(io_tree, ordered_extent->file_offset,
3008                              ordered_extent->file_offset +
3009                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
3010 out:
3011         if (root != fs_info->tree_root)
3012                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
3013         if (trans)
3014                 btrfs_end_transaction(trans, root);
3015
3016         if (ret || truncated) {
3017                 u64 start, end;
3018
3019                 if (truncated)
3020                         start = ordered_extent->file_offset + logical_len;
3021                 else
3022                         start = ordered_extent->file_offset;
3023                 end = ordered_extent->file_offset + ordered_extent->len - 1;
3024                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
3025
3026                 /* Drop the cache for the part of the extent we didn't write. */
3027                 btrfs_drop_extent_cache(inode, start, end, 0);
3028
3029                 /*
3030                  * If the ordered extent had an IOERR or something else went
3031                  * wrong we need to return the space for this ordered extent
3032                  * back to the allocator.  We only free the extent in the
3033                  * truncated case if we didn't write out the extent at all.
3034                  */
3035                 if ((ret || !logical_len) &&
3036                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
3037                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
3038                         btrfs_free_reserved_extent(fs_info,
3039                                                    ordered_extent->start,
3040                                                    ordered_extent->disk_len, 1);
3041         }
3042
3043
3044         /*
3045          * This needs to be done to make sure anybody waiting knows we are done
3046          * updating everything for this ordered extent.
3047          */
3048         btrfs_remove_ordered_extent(inode, ordered_extent);
3049
3050         /* for snapshot-aware defrag */
3051         if (new) {
3052                 if (ret) {
3053                         free_sa_defrag_extent(new);
3054                         atomic_dec(&fs_info->defrag_running);
3055                 } else {
3056                         relink_file_extents(new);
3057                 }
3058         }
3059
3060         /* once for us */
3061         btrfs_put_ordered_extent(ordered_extent);
3062         /* once for the tree */
3063         btrfs_put_ordered_extent(ordered_extent);
3064
3065         return ret;
3066 }
3067
3068 static void finish_ordered_fn(struct btrfs_work *work)
3069 {
3070         struct btrfs_ordered_extent *ordered_extent;
3071         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
3072         btrfs_finish_ordered_io(ordered_extent);
3073 }
3074
3075 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
3076                                 struct extent_state *state, int uptodate)
3077 {
3078         struct inode *inode = page->mapping->host;
3079         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3080         struct btrfs_ordered_extent *ordered_extent = NULL;
3081         struct btrfs_workqueue *wq;
3082         btrfs_work_func_t func;
3083
3084         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
3085
3086         ClearPagePrivate2(page);
3087         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
3088                                             end - start + 1, uptodate))
3089                 return 0;
3090
3091         if (btrfs_is_free_space_inode(inode)) {
3092                 wq = fs_info->endio_freespace_worker;
3093                 func = btrfs_freespace_write_helper;
3094         } else {
3095                 wq = fs_info->endio_write_workers;
3096                 func = btrfs_endio_write_helper;
3097         }
3098
3099         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
3100                         NULL);
3101         btrfs_queue_work(wq, &ordered_extent->work);
3102
3103         return 0;
3104 }
3105
3106 static int __readpage_endio_check(struct inode *inode,
3107                                   struct btrfs_io_bio *io_bio,
3108                                   int icsum, struct page *page,
3109                                   int pgoff, u64 start, size_t len)
3110 {
3111         char *kaddr;
3112         u32 csum_expected;
3113         u32 csum = ~(u32)0;
3114
3115         csum_expected = *(((u32 *)io_bio->csum) + icsum);
3116
3117         kaddr = kmap_atomic(page);
3118         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
3119         btrfs_csum_final(csum, (u8 *)&csum);
3120         if (csum != csum_expected)
3121                 goto zeroit;
3122
3123         kunmap_atomic(kaddr);
3124         return 0;
3125 zeroit:
3126         btrfs_warn_rl(BTRFS_I(inode)->root->fs_info,
3127                 "csum failed ino %llu off %llu csum %u expected csum %u",
3128                            btrfs_ino(inode), start, csum, csum_expected);
3129         memset(kaddr + pgoff, 1, len);
3130         flush_dcache_page(page);
3131         kunmap_atomic(kaddr);
3132         if (csum_expected == 0)
3133                 return 0;
3134         return -EIO;
3135 }
3136
3137 /*
3138  * when reads are done, we need to check csums to verify the data is correct
3139  * if there's a match, we allow the bio to finish.  If not, the code in
3140  * extent_io.c will try to find good copies for us.
3141  */
3142 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
3143                                       u64 phy_offset, struct page *page,
3144                                       u64 start, u64 end, int mirror)
3145 {
3146         size_t offset = start - page_offset(page);
3147         struct inode *inode = page->mapping->host;
3148         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3149         struct btrfs_root *root = BTRFS_I(inode)->root;
3150
3151         if (PageChecked(page)) {
3152                 ClearPageChecked(page);
3153                 return 0;
3154         }
3155
3156         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
3157                 return 0;
3158
3159         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
3160             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
3161                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM);
3162                 return 0;
3163         }
3164
3165         phy_offset >>= inode->i_sb->s_blocksize_bits;
3166         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
3167                                       start, (size_t)(end - start + 1));
3168 }
3169
3170 void btrfs_add_delayed_iput(struct inode *inode)
3171 {
3172         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3173         struct btrfs_inode *binode = BTRFS_I(inode);
3174
3175         if (atomic_add_unless(&inode->i_count, -1, 1))
3176                 return;
3177
3178         spin_lock(&fs_info->delayed_iput_lock);
3179         if (binode->delayed_iput_count == 0) {
3180                 ASSERT(list_empty(&binode->delayed_iput));
3181                 list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
3182         } else {
3183                 binode->delayed_iput_count++;
3184         }
3185         spin_unlock(&fs_info->delayed_iput_lock);
3186 }
3187
3188 void btrfs_run_delayed_iputs(struct btrfs_fs_info *fs_info)
3189 {
3190
3191         spin_lock(&fs_info->delayed_iput_lock);
3192         while (!list_empty(&fs_info->delayed_iputs)) {
3193                 struct btrfs_inode *inode;
3194
3195                 inode = list_first_entry(&fs_info->delayed_iputs,
3196                                 struct btrfs_inode, delayed_iput);
3197                 if (inode->delayed_iput_count) {
3198                         inode->delayed_iput_count--;
3199                         list_move_tail(&inode->delayed_iput,
3200                                         &fs_info->delayed_iputs);
3201                 } else {
3202                         list_del_init(&inode->delayed_iput);
3203                 }
3204                 spin_unlock(&fs_info->delayed_iput_lock);
3205                 iput(&inode->vfs_inode);
3206                 spin_lock(&fs_info->delayed_iput_lock);
3207         }
3208         spin_unlock(&fs_info->delayed_iput_lock);
3209 }
3210
3211 /*
3212  * This is called in transaction commit time. If there are no orphan
3213  * files in the subvolume, it removes orphan item and frees block_rsv
3214  * structure.
3215  */
3216 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
3217                               struct btrfs_root *root)
3218 {
3219         struct btrfs_fs_info *fs_info = root->fs_info;
3220         struct btrfs_block_rsv *block_rsv;
3221         int ret;
3222
3223         if (atomic_read(&root->orphan_inodes) ||
3224             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
3225                 return;
3226
3227         spin_lock(&root->orphan_lock);
3228         if (atomic_read(&root->orphan_inodes)) {
3229                 spin_unlock(&root->orphan_lock);
3230                 return;
3231         }
3232
3233         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
3234                 spin_unlock(&root->orphan_lock);
3235                 return;
3236         }
3237
3238         block_rsv = root->orphan_block_rsv;
3239         root->orphan_block_rsv = NULL;
3240         spin_unlock(&root->orphan_lock);
3241
3242         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
3243             btrfs_root_refs(&root->root_item) > 0) {
3244                 ret = btrfs_del_orphan_item(trans, fs_info->tree_root,
3245                                             root->root_key.objectid);
3246                 if (ret)
3247                         btrfs_abort_transaction(trans, ret);
3248                 else
3249                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
3250                                   &root->state);
3251         }
3252
3253         if (block_rsv) {
3254                 WARN_ON(block_rsv->size > 0);
3255                 btrfs_free_block_rsv(fs_info, block_rsv);
3256         }
3257 }
3258
3259 /*
3260  * This creates an orphan entry for the given inode in case something goes
3261  * wrong in the middle of an unlink/truncate.
3262  *
3263  * NOTE: caller of this function should reserve 5 units of metadata for
3264  *       this function.
3265  */
3266 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3267 {
3268         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3269         struct btrfs_root *root = BTRFS_I(inode)->root;
3270         struct btrfs_block_rsv *block_rsv = NULL;
3271         int reserve = 0;
3272         int insert = 0;
3273         int ret;
3274
3275         if (!root->orphan_block_rsv) {
3276                 block_rsv = btrfs_alloc_block_rsv(fs_info,
3277                                                   BTRFS_BLOCK_RSV_TEMP);
3278                 if (!block_rsv)
3279                         return -ENOMEM;
3280         }
3281
3282         spin_lock(&root->orphan_lock);
3283         if (!root->orphan_block_rsv) {
3284                 root->orphan_block_rsv = block_rsv;
3285         } else if (block_rsv) {
3286                 btrfs_free_block_rsv(fs_info, block_rsv);
3287                 block_rsv = NULL;
3288         }
3289
3290         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3291                               &BTRFS_I(inode)->runtime_flags)) {
3292 #if 0
3293                 /*
3294                  * For proper ENOSPC handling, we should do orphan
3295                  * cleanup when mounting. But this introduces backward
3296                  * compatibility issue.
3297                  */
3298                 if (!xchg(&root->orphan_item_inserted, 1))
3299                         insert = 2;
3300                 else
3301                         insert = 1;
3302 #endif
3303                 insert = 1;
3304                 atomic_inc(&root->orphan_inodes);
3305         }
3306
3307         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3308                               &BTRFS_I(inode)->runtime_flags))
3309                 reserve = 1;
3310         spin_unlock(&root->orphan_lock);
3311
3312         /* grab metadata reservation from transaction handle */
3313         if (reserve) {
3314                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3315                 ASSERT(!ret);
3316                 if (ret) {
3317                         atomic_dec(&root->orphan_inodes);
3318                         clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3319                                   &BTRFS_I(inode)->runtime_flags);
3320                         if (insert)
3321                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3322                                           &BTRFS_I(inode)->runtime_flags);
3323                         return ret;
3324                 }
3325         }
3326
3327         /* insert an orphan item to track this unlinked/truncated file */
3328         if (insert >= 1) {
3329                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3330                 if (ret) {
3331                         atomic_dec(&root->orphan_inodes);
3332                         if (reserve) {
3333                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3334                                           &BTRFS_I(inode)->runtime_flags);
3335                                 btrfs_orphan_release_metadata(inode);
3336                         }
3337                         if (ret != -EEXIST) {
3338                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3339                                           &BTRFS_I(inode)->runtime_flags);
3340                                 btrfs_abort_transaction(trans, ret);
3341                                 return ret;
3342                         }
3343                 }
3344                 ret = 0;
3345         }
3346
3347         /* insert an orphan item to track subvolume contains orphan files */
3348         if (insert >= 2) {
3349                 ret = btrfs_insert_orphan_item(trans, fs_info->tree_root,
3350                                                root->root_key.objectid);
3351                 if (ret && ret != -EEXIST) {
3352                         btrfs_abort_transaction(trans, ret);
3353                         return ret;
3354                 }
3355         }
3356         return 0;
3357 }
3358
3359 /*
3360  * We have done the truncate/delete so we can go ahead and remove the orphan
3361  * item for this particular inode.
3362  */
3363 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3364                             struct inode *inode)
3365 {
3366         struct btrfs_root *root = BTRFS_I(inode)->root;
3367         int delete_item = 0;
3368         int release_rsv = 0;
3369         int ret = 0;
3370
3371         spin_lock(&root->orphan_lock);
3372         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3373                                &BTRFS_I(inode)->runtime_flags))
3374                 delete_item = 1;
3375
3376         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3377                                &BTRFS_I(inode)->runtime_flags))
3378                 release_rsv = 1;
3379         spin_unlock(&root->orphan_lock);
3380
3381         if (delete_item) {
3382                 atomic_dec(&root->orphan_inodes);
3383                 if (trans)
3384                         ret = btrfs_del_orphan_item(trans, root,
3385                                                     btrfs_ino(inode));
3386         }
3387
3388         if (release_rsv)
3389                 btrfs_orphan_release_metadata(inode);
3390
3391         return ret;
3392 }
3393
3394 /*
3395  * this cleans up any orphans that may be left on the list from the last use
3396  * of this root.
3397  */
3398 int btrfs_orphan_cleanup(struct btrfs_root *root)
3399 {
3400         struct btrfs_fs_info *fs_info = root->fs_info;
3401         struct btrfs_path *path;
3402         struct extent_buffer *leaf;
3403         struct btrfs_key key, found_key;
3404         struct btrfs_trans_handle *trans;
3405         struct inode *inode;
3406         u64 last_objectid = 0;
3407         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3408
3409         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3410                 return 0;
3411
3412         path = btrfs_alloc_path();
3413         if (!path) {
3414                 ret = -ENOMEM;
3415                 goto out;
3416         }
3417         path->reada = READA_BACK;
3418
3419         key.objectid = BTRFS_ORPHAN_OBJECTID;
3420         key.type = BTRFS_ORPHAN_ITEM_KEY;
3421         key.offset = (u64)-1;
3422
3423         while (1) {
3424                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3425                 if (ret < 0)
3426                         goto out;
3427
3428                 /*
3429                  * if ret == 0 means we found what we were searching for, which
3430                  * is weird, but possible, so only screw with path if we didn't
3431                  * find the key and see if we have stuff that matches
3432                  */
3433                 if (ret > 0) {
3434                         ret = 0;
3435                         if (path->slots[0] == 0)
3436                                 break;
3437                         path->slots[0]--;
3438                 }
3439
3440                 /* pull out the item */
3441                 leaf = path->nodes[0];
3442                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3443
3444                 /* make sure the item matches what we want */
3445                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3446                         break;
3447                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3448                         break;
3449
3450                 /* release the path since we're done with it */
3451                 btrfs_release_path(path);
3452
3453                 /*
3454                  * this is where we are basically btrfs_lookup, without the
3455                  * crossing root thing.  we store the inode number in the
3456                  * offset of the orphan item.
3457                  */
3458
3459                 if (found_key.offset == last_objectid) {
3460                         btrfs_err(fs_info,
3461                                   "Error removing orphan entry, stopping orphan cleanup");
3462                         ret = -EINVAL;
3463                         goto out;
3464                 }
3465
3466                 last_objectid = found_key.offset;
3467
3468                 found_key.objectid = found_key.offset;
3469                 found_key.type = BTRFS_INODE_ITEM_KEY;
3470                 found_key.offset = 0;
3471                 inode = btrfs_iget(fs_info->sb, &found_key, root, NULL);
3472                 ret = PTR_ERR_OR_ZERO(inode);
3473                 if (ret && ret != -ENOENT)
3474                         goto out;
3475
3476                 if (ret == -ENOENT && root == fs_info->tree_root) {
3477                         struct btrfs_root *dead_root;
3478                         struct btrfs_fs_info *fs_info = root->fs_info;
3479                         int is_dead_root = 0;
3480
3481                         /*
3482                          * this is an orphan in the tree root. Currently these
3483                          * could come from 2 sources:
3484                          *  a) a snapshot deletion in progress
3485                          *  b) a free space cache inode
3486                          * We need to distinguish those two, as the snapshot
3487                          * orphan must not get deleted.
3488                          * find_dead_roots already ran before us, so if this
3489                          * is a snapshot deletion, we should find the root
3490                          * in the dead_roots list
3491                          */
3492                         spin_lock(&fs_info->trans_lock);
3493                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3494                                             root_list) {
3495                                 if (dead_root->root_key.objectid ==
3496                                     found_key.objectid) {
3497                                         is_dead_root = 1;
3498                                         break;
3499                                 }
3500                         }
3501                         spin_unlock(&fs_info->trans_lock);
3502                         if (is_dead_root) {
3503                                 /* prevent this orphan from being found again */
3504                                 key.offset = found_key.objectid - 1;
3505                                 continue;
3506                         }
3507                 }
3508                 /*
3509                  * Inode is already gone but the orphan item is still there,
3510                  * kill the orphan item.
3511                  */
3512                 if (ret == -ENOENT) {
3513                         trans = btrfs_start_transaction(root, 1);
3514                         if (IS_ERR(trans)) {
3515                                 ret = PTR_ERR(trans);
3516                                 goto out;
3517                         }
3518                         btrfs_debug(fs_info, "auto deleting %Lu",
3519                                     found_key.objectid);
3520                         ret = btrfs_del_orphan_item(trans, root,
3521                                                     found_key.objectid);
3522                         btrfs_end_transaction(trans, root);
3523                         if (ret)
3524                                 goto out;
3525                         continue;
3526                 }
3527
3528                 /*
3529                  * add this inode to the orphan list so btrfs_orphan_del does
3530                  * the proper thing when we hit it
3531                  */
3532                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3533                         &BTRFS_I(inode)->runtime_flags);
3534                 atomic_inc(&root->orphan_inodes);
3535
3536                 /* if we have links, this was a truncate, lets do that */
3537                 if (inode->i_nlink) {
3538                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3539                                 iput(inode);
3540                                 continue;
3541                         }
3542                         nr_truncate++;
3543
3544                         /* 1 for the orphan item deletion. */
3545                         trans = btrfs_start_transaction(root, 1);
3546                         if (IS_ERR(trans)) {
3547                                 iput(inode);
3548                                 ret = PTR_ERR(trans);
3549                                 goto out;
3550                         }
3551                         ret = btrfs_orphan_add(trans, inode);
3552                         btrfs_end_transaction(trans, root);
3553                         if (ret) {
3554                                 iput(inode);
3555                                 goto out;
3556                         }
3557
3558                         ret = btrfs_truncate(inode);
3559                         if (ret)
3560                                 btrfs_orphan_del(NULL, inode);
3561                 } else {
3562                         nr_unlink++;
3563                 }
3564
3565                 /* this will do delete_inode and everything for us */
3566                 iput(inode);
3567                 if (ret)
3568                         goto out;
3569         }
3570         /* release the path since we're done with it */
3571         btrfs_release_path(path);
3572
3573         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3574
3575         if (root->orphan_block_rsv)
3576                 btrfs_block_rsv_release(fs_info, root->orphan_block_rsv,
3577                                         (u64)-1);
3578
3579         if (root->orphan_block_rsv ||
3580             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3581                 trans = btrfs_join_transaction(root);
3582                 if (!IS_ERR(trans))
3583                         btrfs_end_transaction(trans, root);
3584         }
3585
3586         if (nr_unlink)
3587                 btrfs_debug(fs_info, "unlinked %d orphans", nr_unlink);
3588         if (nr_truncate)
3589                 btrfs_debug(fs_info, "truncated %d orphans", nr_truncate);
3590
3591 out:
3592         if (ret)
3593                 btrfs_err(fs_info, "could not do orphan cleanup %d", ret);
3594         btrfs_free_path(path);
3595         return ret;
3596 }
3597
3598 /*
3599  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3600  * don't find any xattrs, we know there can't be any acls.
3601  *
3602  * slot is the slot the inode is in, objectid is the objectid of the inode
3603  */
3604 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3605                                           int slot, u64 objectid,
3606                                           int *first_xattr_slot)
3607 {
3608         u32 nritems = btrfs_header_nritems(leaf);
3609         struct btrfs_key found_key;
3610         static u64 xattr_access = 0;
3611         static u64 xattr_default = 0;
3612         int scanned = 0;
3613
3614         if (!xattr_access) {
3615                 xattr_access = btrfs_name_hash(XATTR_NAME_POSIX_ACL_ACCESS,
3616                                         strlen(XATTR_NAME_POSIX_ACL_ACCESS));
3617                 xattr_default = btrfs_name_hash(XATTR_NAME_POSIX_ACL_DEFAULT,
3618                                         strlen(XATTR_NAME_POSIX_ACL_DEFAULT));
3619         }
3620
3621         slot++;
3622         *first_xattr_slot = -1;
3623         while (slot < nritems) {
3624                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3625
3626                 /* we found a different objectid, there must not be acls */
3627                 if (found_key.objectid != objectid)
3628                         return 0;
3629
3630                 /* we found an xattr, assume we've got an acl */
3631                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3632                         if (*first_xattr_slot == -1)
3633                                 *first_xattr_slot = slot;
3634                         if (found_key.offset == xattr_access ||
3635                             found_key.offset == xattr_default)
3636                                 return 1;
3637                 }
3638
3639                 /*
3640                  * we found a key greater than an xattr key, there can't
3641                  * be any acls later on
3642                  */
3643                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3644                         return 0;
3645
3646                 slot++;
3647                 scanned++;
3648
3649                 /*
3650                  * it goes inode, inode backrefs, xattrs, extents,
3651                  * so if there are a ton of hard links to an inode there can
3652                  * be a lot of backrefs.  Don't waste time searching too hard,
3653                  * this is just an optimization
3654                  */
3655                 if (scanned >= 8)
3656                         break;
3657         }
3658         /* we hit the end of the leaf before we found an xattr or
3659          * something larger than an xattr.  We have to assume the inode
3660          * has acls
3661          */
3662         if (*first_xattr_slot == -1)
3663                 *first_xattr_slot = slot;
3664         return 1;
3665 }
3666
3667 /*
3668  * read an inode from the btree into the in-memory inode
3669  */
3670 static int btrfs_read_locked_inode(struct inode *inode)
3671 {
3672         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3673         struct btrfs_path *path;
3674         struct extent_buffer *leaf;
3675         struct btrfs_inode_item *inode_item;
3676         struct btrfs_root *root = BTRFS_I(inode)->root;
3677         struct btrfs_key location;
3678         unsigned long ptr;
3679         int maybe_acls;
3680         u32 rdev;
3681         int ret;
3682         bool filled = false;
3683         int first_xattr_slot;
3684
3685         ret = btrfs_fill_inode(inode, &rdev);
3686         if (!ret)
3687                 filled = true;
3688
3689         path = btrfs_alloc_path();
3690         if (!path) {
3691                 ret = -ENOMEM;
3692                 goto make_bad;
3693         }
3694
3695         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3696
3697         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3698         if (ret) {
3699                 if (ret > 0)
3700                         ret = -ENOENT;
3701                 goto make_bad;
3702         }
3703
3704         leaf = path->nodes[0];
3705
3706         if (filled)
3707                 goto cache_index;
3708
3709         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3710                                     struct btrfs_inode_item);
3711         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3712         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3713         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3714         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3715         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3716
3717         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3718         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3719
3720         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3721         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3722
3723         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3724         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3725
3726         BTRFS_I(inode)->i_otime.tv_sec =
3727                 btrfs_timespec_sec(leaf, &inode_item->otime);
3728         BTRFS_I(inode)->i_otime.tv_nsec =
3729                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3730
3731         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3732         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3733         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3734
3735         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3736         inode->i_generation = BTRFS_I(inode)->generation;
3737         inode->i_rdev = 0;
3738         rdev = btrfs_inode_rdev(leaf, inode_item);
3739
3740         BTRFS_I(inode)->index_cnt = (u64)-1;
3741         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3742
3743 cache_index:
3744         /*
3745          * If we were modified in the current generation and evicted from memory
3746          * and then re-read we need to do a full sync since we don't have any
3747          * idea about which extents were modified before we were evicted from
3748          * cache.
3749          *
3750          * This is required for both inode re-read from disk and delayed inode
3751          * in delayed_nodes_tree.
3752          */
3753         if (BTRFS_I(inode)->last_trans == fs_info->generation)
3754                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3755                         &BTRFS_I(inode)->runtime_flags);
3756
3757         /*
3758          * We don't persist the id of the transaction where an unlink operation
3759          * against the inode was last made. So here we assume the inode might
3760          * have been evicted, and therefore the exact value of last_unlink_trans
3761          * lost, and set it to last_trans to avoid metadata inconsistencies
3762          * between the inode and its parent if the inode is fsync'ed and the log
3763          * replayed. For example, in the scenario:
3764          *
3765          * touch mydir/foo
3766          * ln mydir/foo mydir/bar
3767          * sync
3768          * unlink mydir/bar
3769          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3770          * xfs_io -c fsync mydir/foo
3771          * <power failure>
3772          * mount fs, triggers fsync log replay
3773          *
3774          * We must make sure that when we fsync our inode foo we also log its
3775          * parent inode, otherwise after log replay the parent still has the
3776          * dentry with the "bar" name but our inode foo has a link count of 1
3777          * and doesn't have an inode ref with the name "bar" anymore.
3778          *
3779          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3780          * but it guarantees correctness at the expense of occasional full
3781          * transaction commits on fsync if our inode is a directory, or if our
3782          * inode is not a directory, logging its parent unnecessarily.
3783          */
3784         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3785
3786         path->slots[0]++;
3787         if (inode->i_nlink != 1 ||
3788             path->slots[0] >= btrfs_header_nritems(leaf))
3789                 goto cache_acl;
3790
3791         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3792         if (location.objectid != btrfs_ino(inode))
3793                 goto cache_acl;
3794
3795         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3796         if (location.type == BTRFS_INODE_REF_KEY) {
3797                 struct btrfs_inode_ref *ref;
3798
3799                 ref = (struct btrfs_inode_ref *)ptr;
3800                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3801         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3802                 struct btrfs_inode_extref *extref;
3803
3804                 extref = (struct btrfs_inode_extref *)ptr;
3805                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3806                                                                      extref);
3807         }
3808 cache_acl:
3809         /*
3810          * try to precache a NULL acl entry for files that don't have
3811          * any xattrs or acls
3812          */
3813         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3814                                            btrfs_ino(inode), &first_xattr_slot);
3815         if (first_xattr_slot != -1) {
3816                 path->slots[0] = first_xattr_slot;
3817                 ret = btrfs_load_inode_props(inode, path);
3818                 if (ret)
3819                         btrfs_err(fs_info,
3820                                   "error loading props for ino %llu (root %llu): %d",
3821                                   btrfs_ino(inode),
3822                                   root->root_key.objectid, ret);
3823         }
3824         btrfs_free_path(path);
3825
3826         if (!maybe_acls)
3827                 cache_no_acl(inode);
3828
3829         switch (inode->i_mode & S_IFMT) {
3830         case S_IFREG:
3831                 inode->i_mapping->a_ops = &btrfs_aops;
3832                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3833                 inode->i_fop = &btrfs_file_operations;
3834                 inode->i_op = &btrfs_file_inode_operations;
3835                 break;
3836         case S_IFDIR:
3837                 inode->i_fop = &btrfs_dir_file_operations;
3838                 if (root == fs_info->tree_root)
3839                         inode->i_op = &btrfs_dir_ro_inode_operations;
3840                 else
3841                         inode->i_op = &btrfs_dir_inode_operations;
3842                 break;
3843         case S_IFLNK:
3844                 inode->i_op = &btrfs_symlink_inode_operations;
3845                 inode_nohighmem(inode);
3846                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3847                 break;
3848         default:
3849                 inode->i_op = &btrfs_special_inode_operations;
3850                 init_special_inode(inode, inode->i_mode, rdev);
3851                 break;
3852         }
3853
3854         btrfs_update_iflags(inode);
3855         return 0;
3856
3857 make_bad:
3858         btrfs_free_path(path);
3859         make_bad_inode(inode);
3860         return ret;
3861 }
3862
3863 /*
3864  * given a leaf and an inode, copy the inode fields into the leaf
3865  */
3866 static void fill_inode_item(struct btrfs_trans_handle *trans,
3867                             struct extent_buffer *leaf,
3868                             struct btrfs_inode_item *item,
3869                             struct inode *inode)
3870 {
3871         struct btrfs_map_token token;
3872
3873         btrfs_init_map_token(&token);
3874
3875         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3876         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3877         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3878                                    &token);
3879         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3880         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3881
3882         btrfs_set_token_timespec_sec(leaf, &item->atime,
3883                                      inode->i_atime.tv_sec, &token);
3884         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3885                                       inode->i_atime.tv_nsec, &token);
3886
3887         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3888                                      inode->i_mtime.tv_sec, &token);
3889         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3890                                       inode->i_mtime.tv_nsec, &token);
3891
3892         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3893                                      inode->i_ctime.tv_sec, &token);
3894         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3895                                       inode->i_ctime.tv_nsec, &token);
3896
3897         btrfs_set_token_timespec_sec(leaf, &item->otime,
3898                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3899         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3900                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3901
3902         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3903                                      &token);
3904         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3905                                          &token);
3906         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3907         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3908         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3909         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3910         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3911 }
3912
3913 /*
3914  * copy everything in the in-memory inode into the btree.
3915  */
3916 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3917                                 struct btrfs_root *root, struct inode *inode)
3918 {
3919         struct btrfs_inode_item *inode_item;
3920         struct btrfs_path *path;
3921         struct extent_buffer *leaf;
3922         int ret;
3923
3924         path = btrfs_alloc_path();
3925         if (!path)
3926                 return -ENOMEM;
3927
3928         path->leave_spinning = 1;
3929         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3930                                  1);
3931         if (ret) {
3932                 if (ret > 0)
3933                         ret = -ENOENT;
3934                 goto failed;
3935         }
3936
3937         leaf = path->nodes[0];
3938         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3939                                     struct btrfs_inode_item);
3940
3941         fill_inode_item(trans, leaf, inode_item, inode);
3942         btrfs_mark_buffer_dirty(leaf);
3943         btrfs_set_inode_last_trans(trans, inode);
3944         ret = 0;
3945 failed:
3946         btrfs_free_path(path);
3947         return ret;
3948 }
3949
3950 /*
3951  * copy everything in the in-memory inode into the btree.
3952  */
3953 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3954                                 struct btrfs_root *root, struct inode *inode)
3955 {
3956         struct btrfs_fs_info *fs_info = root->fs_info;
3957         int ret;
3958
3959         /*
3960          * If the inode is a free space inode, we can deadlock during commit
3961          * if we put it into the delayed code.
3962          *
3963          * The data relocation inode should also be directly updated
3964          * without delay
3965          */
3966         if (!btrfs_is_free_space_inode(inode)
3967             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3968             && !test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
3969                 btrfs_update_root_times(trans, root);
3970
3971                 ret = btrfs_delayed_update_inode(trans, root, inode);
3972                 if (!ret)
3973                         btrfs_set_inode_last_trans(trans, inode);
3974                 return ret;
3975         }
3976
3977         return btrfs_update_inode_item(trans, root, inode);
3978 }
3979
3980 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3981                                          struct btrfs_root *root,
3982                                          struct inode *inode)
3983 {
3984         int ret;
3985
3986         ret = btrfs_update_inode(trans, root, inode);
3987         if (ret == -ENOSPC)
3988                 return btrfs_update_inode_item(trans, root, inode);
3989         return ret;
3990 }
3991
3992 /*
3993  * unlink helper that gets used here in inode.c and in the tree logging
3994  * recovery code.  It remove a link in a directory with a given name, and
3995  * also drops the back refs in the inode to the directory
3996  */
3997 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3998                                 struct btrfs_root *root,
3999                                 struct inode *dir, struct inode *inode,
4000                                 const char *name, int name_len)
4001 {
4002         struct btrfs_fs_info *fs_info = root->fs_info;
4003         struct btrfs_path *path;
4004         int ret = 0;
4005         struct extent_buffer *leaf;
4006         struct btrfs_dir_item *di;
4007         struct btrfs_key key;
4008         u64 index;
4009         u64 ino = btrfs_ino(inode);
4010         u64 dir_ino = btrfs_ino(dir);
4011
4012         path = btrfs_alloc_path();
4013         if (!path) {
4014                 ret = -ENOMEM;
4015                 goto out;
4016         }
4017
4018         path->leave_spinning = 1;
4019         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4020                                     name, name_len, -1);
4021         if (IS_ERR(di)) {
4022                 ret = PTR_ERR(di);
4023                 goto err;
4024         }
4025         if (!di) {
4026                 ret = -ENOENT;
4027                 goto err;
4028         }
4029         leaf = path->nodes[0];
4030         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4031         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4032         if (ret)
4033                 goto err;
4034         btrfs_release_path(path);
4035
4036         /*
4037          * If we don't have dir index, we have to get it by looking up
4038          * the inode ref, since we get the inode ref, remove it directly,
4039          * it is unnecessary to do delayed deletion.
4040          *
4041          * But if we have dir index, needn't search inode ref to get it.
4042          * Since the inode ref is close to the inode item, it is better
4043          * that we delay to delete it, and just do this deletion when
4044          * we update the inode item.
4045          */
4046         if (BTRFS_I(inode)->dir_index) {
4047                 ret = btrfs_delayed_delete_inode_ref(inode);
4048                 if (!ret) {
4049                         index = BTRFS_I(inode)->dir_index;
4050                         goto skip_backref;
4051                 }
4052         }
4053
4054         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
4055                                   dir_ino, &index);
4056         if (ret) {
4057                 btrfs_info(fs_info,
4058                         "failed to delete reference to %.*s, inode %llu parent %llu",
4059                         name_len, name, ino, dir_ino);
4060                 btrfs_abort_transaction(trans, ret);
4061                 goto err;
4062         }
4063 skip_backref:
4064         ret = btrfs_delete_delayed_dir_index(trans, fs_info, dir, index);
4065         if (ret) {
4066                 btrfs_abort_transaction(trans, ret);
4067                 goto err;
4068         }
4069
4070         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
4071                                          inode, dir_ino);
4072         if (ret != 0 && ret != -ENOENT) {
4073                 btrfs_abort_transaction(trans, ret);
4074                 goto err;
4075         }
4076
4077         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
4078                                            dir, index);
4079         if (ret == -ENOENT)
4080                 ret = 0;
4081         else if (ret)
4082                 btrfs_abort_transaction(trans, ret);
4083 err:
4084         btrfs_free_path(path);
4085         if (ret)
4086                 goto out;
4087
4088         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4089         inode_inc_iversion(inode);
4090         inode_inc_iversion(dir);
4091         inode->i_ctime = dir->i_mtime =
4092                 dir->i_ctime = current_time(inode);
4093         ret = btrfs_update_inode(trans, root, dir);
4094 out:
4095         return ret;
4096 }
4097
4098 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
4099                        struct btrfs_root *root,
4100                        struct inode *dir, struct inode *inode,
4101                        const char *name, int name_len)
4102 {
4103         int ret;
4104         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
4105         if (!ret) {
4106                 drop_nlink(inode);
4107                 ret = btrfs_update_inode(trans, root, inode);
4108         }
4109         return ret;
4110 }
4111
4112 /*
4113  * helper to start transaction for unlink and rmdir.
4114  *
4115  * unlink and rmdir are special in btrfs, they do not always free space, so
4116  * if we cannot make our reservations the normal way try and see if there is
4117  * plenty of slack room in the global reserve to migrate, otherwise we cannot
4118  * allow the unlink to occur.
4119  */
4120 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
4121 {
4122         struct btrfs_root *root = BTRFS_I(dir)->root;
4123
4124         /*
4125          * 1 for the possible orphan item
4126          * 1 for the dir item
4127          * 1 for the dir index
4128          * 1 for the inode ref
4129          * 1 for the inode
4130          */
4131         return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
4132 }
4133
4134 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
4135 {
4136         struct btrfs_root *root = BTRFS_I(dir)->root;
4137         struct btrfs_trans_handle *trans;
4138         struct inode *inode = d_inode(dentry);
4139         int ret;
4140
4141         trans = __unlink_start_trans(dir);
4142         if (IS_ERR(trans))
4143                 return PTR_ERR(trans);
4144
4145         btrfs_record_unlink_dir(trans, dir, d_inode(dentry), 0);
4146
4147         ret = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4148                                  dentry->d_name.name, dentry->d_name.len);
4149         if (ret)
4150                 goto out;
4151
4152         if (inode->i_nlink == 0) {
4153                 ret = btrfs_orphan_add(trans, inode);
4154                 if (ret)
4155                         goto out;
4156         }
4157
4158 out:
4159         btrfs_end_transaction(trans, root);
4160         btrfs_btree_balance_dirty(root->fs_info);
4161         return ret;
4162 }
4163
4164 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
4165                         struct btrfs_root *root,
4166                         struct inode *dir, u64 objectid,
4167                         const char *name, int name_len)
4168 {
4169         struct btrfs_fs_info *fs_info = root->fs_info;
4170         struct btrfs_path *path;
4171         struct extent_buffer *leaf;
4172         struct btrfs_dir_item *di;
4173         struct btrfs_key key;
4174         u64 index;
4175         int ret;
4176         u64 dir_ino = btrfs_ino(dir);
4177
4178         path = btrfs_alloc_path();
4179         if (!path)
4180                 return -ENOMEM;
4181
4182         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4183                                    name, name_len, -1);
4184         if (IS_ERR_OR_NULL(di)) {
4185                 if (!di)
4186                         ret = -ENOENT;
4187                 else
4188                         ret = PTR_ERR(di);
4189                 goto out;
4190         }
4191
4192         leaf = path->nodes[0];
4193         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4194         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
4195         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4196         if (ret) {
4197                 btrfs_abort_transaction(trans, ret);
4198                 goto out;
4199         }
4200         btrfs_release_path(path);
4201
4202         ret = btrfs_del_root_ref(trans, fs_info, objectid,
4203                                  root->root_key.objectid, dir_ino,
4204                                  &index, name, name_len);
4205         if (ret < 0) {
4206                 if (ret != -ENOENT) {
4207                         btrfs_abort_transaction(trans, ret);
4208                         goto out;
4209                 }
4210                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4211                                                  name, name_len);
4212                 if (IS_ERR_OR_NULL(di)) {
4213                         if (!di)
4214                                 ret = -ENOENT;
4215                         else
4216                                 ret = PTR_ERR(di);
4217                         btrfs_abort_transaction(trans, ret);
4218                         goto out;
4219                 }
4220
4221                 leaf = path->nodes[0];
4222                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4223                 btrfs_release_path(path);
4224                 index = key.offset;
4225         }
4226         btrfs_release_path(path);
4227
4228         ret = btrfs_delete_delayed_dir_index(trans, fs_info, dir, index);
4229         if (ret) {
4230                 btrfs_abort_transaction(trans, ret);
4231                 goto out;
4232         }
4233
4234         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4235         inode_inc_iversion(dir);
4236         dir->i_mtime = dir->i_ctime = current_time(dir);
4237         ret = btrfs_update_inode_fallback(trans, root, dir);
4238         if (ret)
4239                 btrfs_abort_transaction(trans, ret);
4240 out:
4241         btrfs_free_path(path);
4242         return ret;
4243 }
4244
4245 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4246 {
4247         struct inode *inode = d_inode(dentry);
4248         int err = 0;
4249         struct btrfs_root *root = BTRFS_I(dir)->root;
4250         struct btrfs_trans_handle *trans;
4251         u64 last_unlink_trans;
4252
4253         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4254                 return -ENOTEMPTY;
4255         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
4256                 return -EPERM;
4257
4258         trans = __unlink_start_trans(dir);
4259         if (IS_ERR(trans))
4260                 return PTR_ERR(trans);
4261
4262         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4263                 err = btrfs_unlink_subvol(trans, root, dir,
4264                                           BTRFS_I(inode)->location.objectid,
4265                                           dentry->d_name.name,
4266                                           dentry->d_name.len);
4267                 goto out;
4268         }
4269
4270         err = btrfs_orphan_add(trans, inode);
4271         if (err)
4272                 goto out;
4273
4274         last_unlink_trans = BTRFS_I(inode)->last_unlink_trans;
4275
4276         /* now the directory is empty */
4277         err = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4278                                  dentry->d_name.name, dentry->d_name.len);
4279         if (!err) {
4280                 btrfs_i_size_write(inode, 0);
4281                 /*
4282                  * Propagate the last_unlink_trans value of the deleted dir to
4283                  * its parent directory. This is to prevent an unrecoverable
4284                  * log tree in the case we do something like this:
4285                  * 1) create dir foo
4286                  * 2) create snapshot under dir foo
4287                  * 3) delete the snapshot
4288                  * 4) rmdir foo
4289                  * 5) mkdir foo
4290                  * 6) fsync foo or some file inside foo
4291                  */
4292                 if (last_unlink_trans >= trans->transid)
4293                         BTRFS_I(dir)->last_unlink_trans = last_unlink_trans;
4294         }
4295 out:
4296         btrfs_end_transaction(trans, root);
4297         btrfs_btree_balance_dirty(root->fs_info);
4298
4299         return err;
4300 }
4301
4302 static int truncate_space_check(struct btrfs_trans_handle *trans,
4303                                 struct btrfs_root *root,
4304                                 u64 bytes_deleted)
4305 {
4306         struct btrfs_fs_info *fs_info = root->fs_info;
4307         int ret;
4308
4309         /*
4310          * This is only used to apply pressure to the enospc system, we don't
4311          * intend to use this reservation at all.
4312          */
4313         bytes_deleted = btrfs_csum_bytes_to_leaves(fs_info, bytes_deleted);
4314         bytes_deleted *= fs_info->nodesize;
4315         ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
4316                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
4317         if (!ret) {
4318                 trace_btrfs_space_reservation(fs_info, "transaction",
4319                                               trans->transid,
4320                                               bytes_deleted, 1);
4321                 trans->bytes_reserved += bytes_deleted;
4322         }
4323         return ret;
4324
4325 }
4326
4327 static int truncate_inline_extent(struct inode *inode,
4328                                   struct btrfs_path *path,
4329                                   struct btrfs_key *found_key,
4330                                   const u64 item_end,
4331                                   const u64 new_size)
4332 {
4333         struct extent_buffer *leaf = path->nodes[0];
4334         int slot = path->slots[0];
4335         struct btrfs_file_extent_item *fi;
4336         u32 size = (u32)(new_size - found_key->offset);
4337         struct btrfs_root *root = BTRFS_I(inode)->root;
4338
4339         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
4340
4341         if (btrfs_file_extent_compression(leaf, fi) != BTRFS_COMPRESS_NONE) {
4342                 loff_t offset = new_size;
4343                 loff_t page_end = ALIGN(offset, PAGE_SIZE);
4344
4345                 /*
4346                  * Zero out the remaining of the last page of our inline extent,
4347                  * instead of directly truncating our inline extent here - that
4348                  * would be much more complex (decompressing all the data, then
4349                  * compressing the truncated data, which might be bigger than
4350                  * the size of the inline extent, resize the extent, etc).
4351                  * We release the path because to get the page we might need to
4352                  * read the extent item from disk (data not in the page cache).
4353                  */
4354                 btrfs_release_path(path);
4355                 return btrfs_truncate_block(inode, offset, page_end - offset,
4356                                         0);
4357         }
4358
4359         btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4360         size = btrfs_file_extent_calc_inline_size(size);
4361         btrfs_truncate_item(root->fs_info, path, size, 1);
4362
4363         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4364                 inode_sub_bytes(inode, item_end + 1 - new_size);
4365
4366         return 0;
4367 }
4368
4369 /*
4370  * this can truncate away extent items, csum items and directory items.
4371  * It starts at a high offset and removes keys until it can't find
4372  * any higher than new_size
4373  *
4374  * csum items that cross the new i_size are truncated to the new size
4375  * as well.
4376  *
4377  * min_type is the minimum key type to truncate down to.  If set to 0, this
4378  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4379  */
4380 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4381                                struct btrfs_root *root,
4382                                struct inode *inode,
4383                                u64 new_size, u32 min_type)
4384 {
4385         struct btrfs_fs_info *fs_info = root->fs_info;
4386         struct btrfs_path *path;
4387         struct extent_buffer *leaf;
4388         struct btrfs_file_extent_item *fi;
4389         struct btrfs_key key;
4390         struct btrfs_key found_key;
4391         u64 extent_start = 0;
4392         u64 extent_num_bytes = 0;
4393         u64 extent_offset = 0;
4394         u64 item_end = 0;
4395         u64 last_size = new_size;
4396         u32 found_type = (u8)-1;
4397         int found_extent;
4398         int del_item;
4399         int pending_del_nr = 0;
4400         int pending_del_slot = 0;
4401         int extent_type = -1;
4402         int ret;
4403         int err = 0;
4404         u64 ino = btrfs_ino(inode);
4405         u64 bytes_deleted = 0;
4406         bool be_nice = 0;
4407         bool should_throttle = 0;
4408         bool should_end = 0;
4409
4410         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4411
4412         /*
4413          * for non-free space inodes and ref cows, we want to back off from
4414          * time to time
4415          */
4416         if (!btrfs_is_free_space_inode(inode) &&
4417             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4418                 be_nice = 1;
4419
4420         path = btrfs_alloc_path();
4421         if (!path)
4422                 return -ENOMEM;
4423         path->reada = READA_BACK;
4424
4425         /*
4426          * We want to drop from the next block forward in case this new size is
4427          * not block aligned since we will be keeping the last block of the
4428          * extent just the way it is.
4429          */
4430         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4431             root == fs_info->tree_root)
4432                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4433                                         fs_info->sectorsize),
4434                                         (u64)-1, 0);
4435
4436         /*
4437          * This function is also used to drop the items in the log tree before
4438          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4439          * it is used to drop the loged items. So we shouldn't kill the delayed
4440          * items.
4441          */
4442         if (min_type == 0 && root == BTRFS_I(inode)->root)
4443                 btrfs_kill_delayed_inode_items(inode);
4444
4445         key.objectid = ino;
4446         key.offset = (u64)-1;
4447         key.type = (u8)-1;
4448
4449 search_again:
4450         /*
4451          * with a 16K leaf size and 128MB extents, you can actually queue
4452          * up a huge file in a single leaf.  Most of the time that
4453          * bytes_deleted is > 0, it will be huge by the time we get here
4454          */
4455         if (be_nice && bytes_deleted > SZ_32M) {
4456                 if (btrfs_should_end_transaction(trans, root)) {
4457                         err = -EAGAIN;
4458                         goto error;
4459                 }
4460         }
4461
4462
4463         path->leave_spinning = 1;
4464         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4465         if (ret < 0) {
4466                 err = ret;
4467                 goto out;
4468         }
4469
4470         if (ret > 0) {
4471                 /* there are no items in the tree for us to truncate, we're
4472                  * done
4473                  */
4474                 if (path->slots[0] == 0)
4475                         goto out;
4476                 path->slots[0]--;
4477         }
4478
4479         while (1) {
4480                 fi = NULL;
4481                 leaf = path->nodes[0];
4482                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4483                 found_type = found_key.type;
4484
4485                 if (found_key.objectid != ino)
4486                         break;
4487
4488                 if (found_type < min_type)
4489                         break;
4490
4491                 item_end = found_key.offset;
4492                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4493                         fi = btrfs_item_ptr(leaf, path->slots[0],
4494                                             struct btrfs_file_extent_item);
4495                         extent_type = btrfs_file_extent_type(leaf, fi);
4496                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4497                                 item_end +=
4498                                     btrfs_file_extent_num_bytes(leaf, fi);
4499                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4500                                 item_end += btrfs_file_extent_inline_len(leaf,
4501                                                          path->slots[0], fi);
4502                         }
4503                         item_end--;
4504                 }
4505                 if (found_type > min_type) {
4506                         del_item = 1;
4507                 } else {
4508                         if (item_end < new_size)
4509                                 break;
4510                         if (found_key.offset >= new_size)
4511                                 del_item = 1;
4512                         else
4513                                 del_item = 0;
4514                 }
4515                 found_extent = 0;
4516                 /* FIXME, shrink the extent if the ref count is only 1 */
4517                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4518                         goto delete;
4519
4520                 if (del_item)
4521                         last_size = found_key.offset;
4522                 else
4523                         last_size = new_size;
4524
4525                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4526                         u64 num_dec;
4527                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4528                         if (!del_item) {
4529                                 u64 orig_num_bytes =
4530                                         btrfs_file_extent_num_bytes(leaf, fi);
4531                                 extent_num_bytes = ALIGN(new_size -
4532                                                 found_key.offset,
4533                                                 fs_info->sectorsize);
4534                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4535                                                          extent_num_bytes);
4536                                 num_dec = (orig_num_bytes -
4537                                            extent_num_bytes);
4538                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4539                                              &root->state) &&
4540                                     extent_start != 0)
4541                                         inode_sub_bytes(inode, num_dec);
4542                                 btrfs_mark_buffer_dirty(leaf);
4543                         } else {
4544                                 extent_num_bytes =
4545                                         btrfs_file_extent_disk_num_bytes(leaf,
4546                                                                          fi);
4547                                 extent_offset = found_key.offset -
4548                                         btrfs_file_extent_offset(leaf, fi);
4549
4550                                 /* FIXME blocksize != 4096 */
4551                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4552                                 if (extent_start != 0) {
4553                                         found_extent = 1;
4554                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4555                                                      &root->state))
4556                                                 inode_sub_bytes(inode, num_dec);
4557                                 }
4558                         }
4559                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4560                         /*
4561                          * we can't truncate inline items that have had
4562                          * special encodings
4563                          */
4564                         if (!del_item &&
4565                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4566                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4567
4568                                 /*
4569                                  * Need to release path in order to truncate a
4570                                  * compressed extent. So delete any accumulated
4571                                  * extent items so far.
4572                                  */
4573                                 if (btrfs_file_extent_compression(leaf, fi) !=
4574                                     BTRFS_COMPRESS_NONE && pending_del_nr) {
4575                                         err = btrfs_del_items(trans, root, path,
4576                                                               pending_del_slot,
4577                                                               pending_del_nr);
4578                                         if (err) {
4579                                                 btrfs_abort_transaction(trans,
4580                                                                         err);
4581                                                 goto error;
4582                                         }
4583                                         pending_del_nr = 0;
4584                                 }
4585
4586                                 err = truncate_inline_extent(inode, path,
4587                                                              &found_key,
4588                                                              item_end,
4589                                                              new_size);
4590                                 if (err) {
4591                                         btrfs_abort_transaction(trans, err);
4592                                         goto error;
4593                                 }
4594                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4595                                             &root->state)) {
4596                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4597                         }
4598                 }
4599 delete:
4600                 if (del_item) {
4601                         if (!pending_del_nr) {
4602                                 /* no pending yet, add ourselves */
4603                                 pending_del_slot = path->slots[0];
4604                                 pending_del_nr = 1;
4605                         } else if (pending_del_nr &&
4606                                    path->slots[0] + 1 == pending_del_slot) {
4607                                 /* hop on the pending chunk */
4608                                 pending_del_nr++;
4609                                 pending_del_slot = path->slots[0];
4610                         } else {
4611                                 BUG();
4612                         }
4613                 } else {
4614                         break;
4615                 }
4616                 should_throttle = 0;
4617
4618                 if (found_extent &&
4619                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4620                      root == fs_info->tree_root)) {
4621                         btrfs_set_path_blocking(path);
4622                         bytes_deleted += extent_num_bytes;
4623                         ret = btrfs_free_extent(trans, fs_info, extent_start,
4624                                                 extent_num_bytes, 0,
4625                                                 btrfs_header_owner(leaf),
4626                                                 ino, extent_offset);
4627                         BUG_ON(ret);
4628                         if (btrfs_should_throttle_delayed_refs(trans, fs_info))
4629                                 btrfs_async_run_delayed_refs(fs_info,
4630                                         trans->delayed_ref_updates * 2,
4631                                         trans->transid, 0);
4632                         if (be_nice) {
4633                                 if (truncate_space_check(trans, root,
4634                                                          extent_num_bytes)) {
4635                                         should_end = 1;
4636                                 }
4637                                 if (btrfs_should_throttle_delayed_refs(trans,
4638                                                                        fs_info))
4639                                         should_throttle = 1;
4640                         }
4641                 }
4642
4643                 if (found_type == BTRFS_INODE_ITEM_KEY)
4644                         break;
4645
4646                 if (path->slots[0] == 0 ||
4647                     path->slots[0] != pending_del_slot ||
4648                     should_throttle || should_end) {
4649                         if (pending_del_nr) {
4650                                 ret = btrfs_del_items(trans, root, path,
4651                                                 pending_del_slot,
4652                                                 pending_del_nr);
4653                                 if (ret) {
4654                                         btrfs_abort_transaction(trans, ret);
4655                                         goto error;
4656                                 }
4657                                 pending_del_nr = 0;
4658                         }
4659                         btrfs_release_path(path);
4660                         if (should_throttle) {
4661                                 unsigned long updates = trans->delayed_ref_updates;
4662                                 if (updates) {
4663                                         trans->delayed_ref_updates = 0;
4664                                         ret = btrfs_run_delayed_refs(trans,
4665                                                                    fs_info,
4666                                                                    updates * 2);
4667                                         if (ret && !err)
4668                                                 err = ret;
4669                                 }
4670                         }
4671                         /*
4672                          * if we failed to refill our space rsv, bail out
4673                          * and let the transaction restart
4674                          */
4675                         if (should_end) {
4676                                 err = -EAGAIN;
4677                                 goto error;
4678                         }
4679                         goto search_again;
4680                 } else {
4681                         path->slots[0]--;
4682                 }
4683         }
4684 out:
4685         if (pending_del_nr) {
4686                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4687                                       pending_del_nr);
4688                 if (ret)
4689                         btrfs_abort_transaction(trans, ret);
4690         }
4691 error:
4692         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
4693                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4694
4695         btrfs_free_path(path);
4696
4697         if (be_nice && bytes_deleted > SZ_32M) {
4698                 unsigned long updates = trans->delayed_ref_updates;
4699                 if (updates) {
4700                         trans->delayed_ref_updates = 0;
4701                         ret = btrfs_run_delayed_refs(trans, fs_info,
4702                                                      updates * 2);
4703                         if (ret && !err)
4704                                 err = ret;
4705                 }
4706         }
4707         return err;
4708 }
4709
4710 /*
4711  * btrfs_truncate_block - read, zero a chunk and write a block
4712  * @inode - inode that we're zeroing
4713  * @from - the offset to start zeroing
4714  * @len - the length to zero, 0 to zero the entire range respective to the
4715  *      offset
4716  * @front - zero up to the offset instead of from the offset on
4717  *
4718  * This will find the block for the "from" offset and cow the block and zero the
4719  * part we want to zero.  This is used with truncate and hole punching.
4720  */
4721 int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
4722                         int front)
4723 {
4724         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4725         struct address_space *mapping = inode->i_mapping;
4726         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4727         struct btrfs_ordered_extent *ordered;
4728         struct extent_state *cached_state = NULL;
4729         char *kaddr;
4730         u32 blocksize = fs_info->sectorsize;
4731         pgoff_t index = from >> PAGE_SHIFT;
4732         unsigned offset = from & (blocksize - 1);
4733         struct page *page;
4734         gfp_t mask = btrfs_alloc_write_mask(mapping);
4735         int ret = 0;
4736         u64 block_start;
4737         u64 block_end;
4738
4739         if ((offset & (blocksize - 1)) == 0 &&
4740             (!len || ((len & (blocksize - 1)) == 0)))
4741                 goto out;
4742
4743         ret = btrfs_delalloc_reserve_space(inode,
4744                         round_down(from, blocksize), blocksize);
4745         if (ret)
4746                 goto out;
4747
4748 again:
4749         page = find_or_create_page(mapping, index, mask);
4750         if (!page) {
4751                 btrfs_delalloc_release_space(inode,
4752                                 round_down(from, blocksize),
4753                                 blocksize);
4754                 ret = -ENOMEM;
4755                 goto out;
4756         }
4757
4758         block_start = round_down(from, blocksize);
4759         block_end = block_start + blocksize - 1;
4760
4761         if (!PageUptodate(page)) {
4762                 ret = btrfs_readpage(NULL, page);
4763                 lock_page(page);
4764                 if (page->mapping != mapping) {
4765                         unlock_page(page);
4766                         put_page(page);
4767                         goto again;
4768                 }
4769                 if (!PageUptodate(page)) {
4770                         ret = -EIO;
4771                         goto out_unlock;
4772                 }
4773         }
4774         wait_on_page_writeback(page);
4775
4776         lock_extent_bits(io_tree, block_start, block_end, &cached_state);
4777         set_page_extent_mapped(page);
4778
4779         ordered = btrfs_lookup_ordered_extent(inode, block_start);
4780         if (ordered) {
4781                 unlock_extent_cached(io_tree, block_start, block_end,
4782                                      &cached_state, GFP_NOFS);
4783                 unlock_page(page);
4784                 put_page(page);
4785                 btrfs_start_ordered_extent(inode, ordered, 1);
4786                 btrfs_put_ordered_extent(ordered);
4787                 goto again;
4788         }
4789
4790         clear_extent_bit(&BTRFS_I(inode)->io_tree, block_start, block_end,
4791                           EXTENT_DIRTY | EXTENT_DELALLOC |
4792                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4793                           0, 0, &cached_state, GFP_NOFS);
4794
4795         ret = btrfs_set_extent_delalloc(inode, block_start, block_end,
4796                                         &cached_state, 0);
4797         if (ret) {
4798                 unlock_extent_cached(io_tree, block_start, block_end,
4799                                      &cached_state, GFP_NOFS);
4800                 goto out_unlock;
4801         }
4802
4803         if (offset != blocksize) {
4804                 if (!len)
4805                         len = blocksize - offset;
4806                 kaddr = kmap(page);
4807                 if (front)
4808                         memset(kaddr + (block_start - page_offset(page)),
4809                                 0, offset);
4810                 else
4811                         memset(kaddr + (block_start - page_offset(page)) +  offset,
4812                                 0, len);
4813                 flush_dcache_page(page);
4814                 kunmap(page);
4815         }
4816         ClearPageChecked(page);
4817         set_page_dirty(page);
4818         unlock_extent_cached(io_tree, block_start, block_end, &cached_state,
4819                              GFP_NOFS);
4820
4821 out_unlock:
4822         if (ret)
4823                 btrfs_delalloc_release_space(inode, block_start,
4824                                              blocksize);
4825         unlock_page(page);
4826         put_page(page);
4827 out:
4828         return ret;
4829 }
4830
4831 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4832                              u64 offset, u64 len)
4833 {
4834         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4835         struct btrfs_trans_handle *trans;
4836         int ret;
4837
4838         /*
4839          * Still need to make sure the inode looks like it's been updated so
4840          * that any holes get logged if we fsync.
4841          */
4842         if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
4843                 BTRFS_I(inode)->last_trans = fs_info->generation;
4844                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4845                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4846                 return 0;
4847         }
4848
4849         /*
4850          * 1 - for the one we're dropping
4851          * 1 - for the one we're adding
4852          * 1 - for updating the inode.
4853          */
4854         trans = btrfs_start_transaction(root, 3);
4855         if (IS_ERR(trans))
4856                 return PTR_ERR(trans);
4857
4858         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4859         if (ret) {
4860                 btrfs_abort_transaction(trans, ret);
4861                 btrfs_end_transaction(trans, root);
4862                 return ret;
4863         }
4864
4865         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4866                                        0, 0, len, 0, len, 0, 0, 0);
4867         if (ret)
4868                 btrfs_abort_transaction(trans, ret);
4869         else
4870                 btrfs_update_inode(trans, root, inode);
4871         btrfs_end_transaction(trans, root);
4872         return ret;
4873 }
4874
4875 /*
4876  * This function puts in dummy file extents for the area we're creating a hole
4877  * for.  So if we are truncating this file to a larger size we need to insert
4878  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4879  * the range between oldsize and size
4880  */
4881 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4882 {
4883         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4884         struct btrfs_root *root = BTRFS_I(inode)->root;
4885         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4886         struct extent_map *em = NULL;
4887         struct extent_state *cached_state = NULL;
4888         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4889         u64 hole_start = ALIGN(oldsize, fs_info->sectorsize);
4890         u64 block_end = ALIGN(size, fs_info->sectorsize);
4891         u64 last_byte;
4892         u64 cur_offset;
4893         u64 hole_size;
4894         int err = 0;
4895
4896         /*
4897          * If our size started in the middle of a block we need to zero out the
4898          * rest of the block before we expand the i_size, otherwise we could
4899          * expose stale data.
4900          */
4901         err = btrfs_truncate_block(inode, oldsize, 0, 0);
4902         if (err)
4903                 return err;
4904
4905         if (size <= hole_start)
4906                 return 0;
4907
4908         while (1) {
4909                 struct btrfs_ordered_extent *ordered;
4910
4911                 lock_extent_bits(io_tree, hole_start, block_end - 1,
4912                                  &cached_state);
4913                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4914                                                      block_end - hole_start);
4915                 if (!ordered)
4916                         break;
4917                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4918                                      &cached_state, GFP_NOFS);
4919                 btrfs_start_ordered_extent(inode, ordered, 1);
4920                 btrfs_put_ordered_extent(ordered);
4921         }
4922
4923         cur_offset = hole_start;
4924         while (1) {
4925                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4926                                 block_end - cur_offset, 0);
4927                 if (IS_ERR(em)) {
4928                         err = PTR_ERR(em);
4929                         em = NULL;
4930                         break;
4931                 }
4932                 last_byte = min(extent_map_end(em), block_end);
4933                 last_byte = ALIGN(last_byte, fs_info->sectorsize);
4934                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4935                         struct extent_map *hole_em;
4936                         hole_size = last_byte - cur_offset;
4937
4938                         err = maybe_insert_hole(root, inode, cur_offset,
4939                                                 hole_size);
4940                         if (err)
4941                                 break;
4942                         btrfs_drop_extent_cache(inode, cur_offset,
4943                                                 cur_offset + hole_size - 1, 0);
4944                         hole_em = alloc_extent_map();
4945                         if (!hole_em) {
4946                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4947                                         &BTRFS_I(inode)->runtime_flags);
4948                                 goto next;
4949                         }
4950                         hole_em->start = cur_offset;
4951                         hole_em->len = hole_size;
4952                         hole_em->orig_start = cur_offset;
4953
4954                         hole_em->block_start = EXTENT_MAP_HOLE;
4955                         hole_em->block_len = 0;
4956                         hole_em->orig_block_len = 0;
4957                         hole_em->ram_bytes = hole_size;
4958                         hole_em->bdev = fs_info->fs_devices->latest_bdev;
4959                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4960                         hole_em->generation = fs_info->generation;
4961
4962                         while (1) {
4963                                 write_lock(&em_tree->lock);
4964                                 err = add_extent_mapping(em_tree, hole_em, 1);
4965                                 write_unlock(&em_tree->lock);
4966                                 if (err != -EEXIST)
4967                                         break;
4968                                 btrfs_drop_extent_cache(inode, cur_offset,
4969                                                         cur_offset +
4970                                                         hole_size - 1, 0);
4971                         }
4972                         free_extent_map(hole_em);
4973                 }
4974 next:
4975                 free_extent_map(em);
4976                 em = NULL;
4977                 cur_offset = last_byte;
4978                 if (cur_offset >= block_end)
4979                         break;
4980         }
4981         free_extent_map(em);
4982         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4983                              GFP_NOFS);
4984         return err;
4985 }
4986
4987 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4988 {
4989         struct btrfs_root *root = BTRFS_I(inode)->root;
4990         struct btrfs_trans_handle *trans;
4991         loff_t oldsize = i_size_read(inode);
4992         loff_t newsize = attr->ia_size;
4993         int mask = attr->ia_valid;
4994         int ret;
4995
4996         /*
4997          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4998          * special case where we need to update the times despite not having
4999          * these flags set.  For all other operations the VFS set these flags
5000          * explicitly if it wants a timestamp update.
5001          */
5002         if (newsize != oldsize) {
5003                 inode_inc_iversion(inode);
5004                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
5005                         inode->i_ctime = inode->i_mtime =
5006                                 current_time(inode);
5007         }
5008
5009         if (newsize > oldsize) {
5010                 /*
5011                  * Don't do an expanding truncate while snapshoting is ongoing.
5012                  * This is to ensure the snapshot captures a fully consistent
5013                  * state of this file - if the snapshot captures this expanding
5014                  * truncation, it must capture all writes that happened before
5015                  * this truncation.
5016                  */
5017                 btrfs_wait_for_snapshot_creation(root);
5018                 ret = btrfs_cont_expand(inode, oldsize, newsize);
5019                 if (ret) {
5020                         btrfs_end_write_no_snapshoting(root);
5021                         return ret;
5022                 }
5023
5024                 trans = btrfs_start_transaction(root, 1);
5025                 if (IS_ERR(trans)) {
5026                         btrfs_end_write_no_snapshoting(root);
5027                         return PTR_ERR(trans);
5028                 }
5029
5030                 i_size_write(inode, newsize);
5031                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
5032                 pagecache_isize_extended(inode, oldsize, newsize);
5033                 ret = btrfs_update_inode(trans, root, inode);
5034                 btrfs_end_write_no_snapshoting(root);
5035                 btrfs_end_transaction(trans, root);
5036         } else {
5037
5038                 /*
5039                  * We're truncating a file that used to have good data down to
5040                  * zero. Make sure it gets into the ordered flush list so that
5041                  * any new writes get down to disk quickly.
5042                  */
5043                 if (newsize == 0)
5044                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
5045                                 &BTRFS_I(inode)->runtime_flags);
5046
5047                 /*
5048                  * 1 for the orphan item we're going to add
5049                  * 1 for the orphan item deletion.
5050                  */
5051                 trans = btrfs_start_transaction(root, 2);
5052                 if (IS_ERR(trans))
5053                         return PTR_ERR(trans);
5054
5055                 /*
5056                  * We need to do this in case we fail at _any_ point during the
5057                  * actual truncate.  Once we do the truncate_setsize we could
5058                  * invalidate pages which forces any outstanding ordered io to
5059                  * be instantly completed which will give us extents that need
5060                  * to be truncated.  If we fail to get an orphan inode down we
5061                  * could have left over extents that were never meant to live,
5062                  * so we need to guarantee from this point on that everything
5063                  * will be consistent.
5064                  */
5065                 ret = btrfs_orphan_add(trans, inode);
5066                 btrfs_end_transaction(trans, root);
5067                 if (ret)
5068                         return ret;
5069
5070                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
5071                 truncate_setsize(inode, newsize);
5072
5073                 /* Disable nonlocked read DIO to avoid the end less truncate */
5074                 btrfs_inode_block_unlocked_dio(inode);
5075                 inode_dio_wait(inode);
5076                 btrfs_inode_resume_unlocked_dio(inode);
5077
5078                 ret = btrfs_truncate(inode);
5079                 if (ret && inode->i_nlink) {
5080                         int err;
5081
5082                         /*
5083                          * failed to truncate, disk_i_size is only adjusted down
5084                          * as we remove extents, so it should represent the true
5085                          * size of the inode, so reset the in memory size and
5086                          * delete our orphan entry.
5087                          */
5088                         trans = btrfs_join_transaction(root);
5089                         if (IS_ERR(trans)) {
5090                                 btrfs_orphan_del(NULL, inode);
5091                                 return ret;
5092                         }
5093                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
5094                         err = btrfs_orphan_del(trans, inode);
5095                         if (err)
5096                                 btrfs_abort_transaction(trans, err);
5097                         btrfs_end_transaction(trans, root);
5098                 }
5099         }
5100
5101         return ret;
5102 }
5103
5104 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
5105 {
5106         struct inode *inode = d_inode(dentry);
5107         struct btrfs_root *root = BTRFS_I(inode)->root;
5108         int err;
5109
5110         if (btrfs_root_readonly(root))
5111                 return -EROFS;
5112
5113         err = setattr_prepare(dentry, attr);
5114         if (err)
5115                 return err;
5116
5117         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
5118                 err = btrfs_setsize(inode, attr);
5119                 if (err)
5120                         return err;
5121         }
5122
5123         if (attr->ia_valid) {
5124                 setattr_copy(inode, attr);
5125                 inode_inc_iversion(inode);
5126                 err = btrfs_dirty_inode(inode);
5127
5128                 if (!err && attr->ia_valid & ATTR_MODE)
5129                         err = posix_acl_chmod(inode, inode->i_mode);
5130         }
5131
5132         return err;
5133 }
5134
5135 /*
5136  * While truncating the inode pages during eviction, we get the VFS calling
5137  * btrfs_invalidatepage() against each page of the inode. This is slow because
5138  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
5139  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
5140  * extent_state structures over and over, wasting lots of time.
5141  *
5142  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
5143  * those expensive operations on a per page basis and do only the ordered io
5144  * finishing, while we release here the extent_map and extent_state structures,
5145  * without the excessive merging and splitting.
5146  */
5147 static void evict_inode_truncate_pages(struct inode *inode)
5148 {
5149         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5150         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
5151         struct rb_node *node;
5152
5153         ASSERT(inode->i_state & I_FREEING);
5154         truncate_inode_pages_final(&inode->i_data);
5155
5156         write_lock(&map_tree->lock);
5157         while (!RB_EMPTY_ROOT(&map_tree->map)) {
5158                 struct extent_map *em;
5159
5160                 node = rb_first(&map_tree->map);
5161                 em = rb_entry(node, struct extent_map, rb_node);
5162                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
5163                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
5164                 remove_extent_mapping(map_tree, em);
5165                 free_extent_map(em);
5166                 if (need_resched()) {
5167                         write_unlock(&map_tree->lock);
5168                         cond_resched();
5169                         write_lock(&map_tree->lock);
5170                 }
5171         }
5172         write_unlock(&map_tree->lock);
5173
5174         /*
5175          * Keep looping until we have no more ranges in the io tree.
5176          * We can have ongoing bios started by readpages (called from readahead)
5177          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
5178          * still in progress (unlocked the pages in the bio but did not yet
5179          * unlocked the ranges in the io tree). Therefore this means some
5180          * ranges can still be locked and eviction started because before
5181          * submitting those bios, which are executed by a separate task (work
5182          * queue kthread), inode references (inode->i_count) were not taken
5183          * (which would be dropped in the end io callback of each bio).
5184          * Therefore here we effectively end up waiting for those bios and
5185          * anyone else holding locked ranges without having bumped the inode's
5186          * reference count - if we don't do it, when they access the inode's
5187          * io_tree to unlock a range it may be too late, leading to an
5188          * use-after-free issue.
5189          */
5190         spin_lock(&io_tree->lock);
5191         while (!RB_EMPTY_ROOT(&io_tree->state)) {
5192                 struct extent_state *state;
5193                 struct extent_state *cached_state = NULL;
5194                 u64 start;
5195                 u64 end;
5196
5197                 node = rb_first(&io_tree->state);
5198                 state = rb_entry(node, struct extent_state, rb_node);
5199                 start = state->start;
5200                 end = state->end;
5201                 spin_unlock(&io_tree->lock);
5202
5203                 lock_extent_bits(io_tree, start, end, &cached_state);
5204
5205                 /*
5206                  * If still has DELALLOC flag, the extent didn't reach disk,
5207                  * and its reserved space won't be freed by delayed_ref.
5208                  * So we need to free its reserved space here.
5209                  * (Refer to comment in btrfs_invalidatepage, case 2)
5210                  *
5211                  * Note, end is the bytenr of last byte, so we need + 1 here.
5212                  */
5213                 if (state->state & EXTENT_DELALLOC)
5214                         btrfs_qgroup_free_data(inode, start, end - start + 1);
5215
5216                 clear_extent_bit(io_tree, start, end,
5217                                  EXTENT_LOCKED | EXTENT_DIRTY |
5218                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
5219                                  EXTENT_DEFRAG, 1, 1,
5220                                  &cached_state, GFP_NOFS);
5221
5222                 cond_resched();
5223                 spin_lock(&io_tree->lock);
5224         }
5225         spin_unlock(&io_tree->lock);
5226 }
5227
5228 void btrfs_evict_inode(struct inode *inode)
5229 {
5230         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5231         struct btrfs_trans_handle *trans;
5232         struct btrfs_root *root = BTRFS_I(inode)->root;
5233         struct btrfs_block_rsv *rsv, *global_rsv;
5234         int steal_from_global = 0;
5235         u64 min_size;
5236         int ret;
5237
5238         trace_btrfs_inode_evict(inode);
5239
5240         if (!root) {
5241                 kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
5242                 return;
5243         }
5244
5245         min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
5246
5247         evict_inode_truncate_pages(inode);
5248
5249         if (inode->i_nlink &&
5250             ((btrfs_root_refs(&root->root_item) != 0 &&
5251               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
5252              btrfs_is_free_space_inode(inode)))
5253                 goto no_delete;
5254
5255         if (is_bad_inode(inode)) {
5256                 btrfs_orphan_del(NULL, inode);
5257                 goto no_delete;
5258         }
5259         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
5260         if (!special_file(inode->i_mode))
5261                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
5262
5263         btrfs_free_io_failure_record(inode, 0, (u64)-1);
5264
5265         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
5266                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
5267                                  &BTRFS_I(inode)->runtime_flags));
5268                 goto no_delete;
5269         }
5270
5271         if (inode->i_nlink > 0) {
5272                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
5273                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
5274                 goto no_delete;
5275         }
5276
5277         ret = btrfs_commit_inode_delayed_inode(inode);
5278         if (ret) {
5279                 btrfs_orphan_del(NULL, inode);
5280                 goto no_delete;
5281         }
5282
5283         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
5284         if (!rsv) {
5285                 btrfs_orphan_del(NULL, inode);
5286                 goto no_delete;
5287         }
5288         rsv->size = min_size;
5289         rsv->failfast = 1;
5290         global_rsv = &fs_info->global_block_rsv;
5291
5292         btrfs_i_size_write(inode, 0);
5293
5294         /*
5295          * This is a bit simpler than btrfs_truncate since we've already
5296          * reserved our space for our orphan item in the unlink, so we just
5297          * need to reserve some slack space in case we add bytes and update
5298          * inode item when doing the truncate.
5299          */
5300         while (1) {
5301                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
5302                                              BTRFS_RESERVE_FLUSH_LIMIT);
5303
5304                 /*
5305                  * Try and steal from the global reserve since we will
5306                  * likely not use this space anyway, we want to try as
5307                  * hard as possible to get this to work.
5308                  */
5309                 if (ret)
5310                         steal_from_global++;
5311                 else
5312                         steal_from_global = 0;
5313                 ret = 0;
5314
5315                 /*
5316                  * steal_from_global == 0: we reserved stuff, hooray!
5317                  * steal_from_global == 1: we didn't reserve stuff, boo!
5318                  * steal_from_global == 2: we've committed, still not a lot of
5319                  * room but maybe we'll have room in the global reserve this
5320                  * time.
5321                  * steal_from_global == 3: abandon all hope!
5322                  */
5323                 if (steal_from_global > 2) {
5324                         btrfs_warn(fs_info,
5325                                    "Could not get space for a delete, will truncate on mount %d",
5326                                    ret);
5327                         btrfs_orphan_del(NULL, inode);
5328                         btrfs_free_block_rsv(fs_info, rsv);
5329                         goto no_delete;
5330                 }
5331
5332                 trans = btrfs_join_transaction(root);
5333                 if (IS_ERR(trans)) {
5334                         btrfs_orphan_del(NULL, inode);
5335                         btrfs_free_block_rsv(fs_info, rsv);
5336                         goto no_delete;
5337                 }
5338
5339                 /*
5340                  * We can't just steal from the global reserve, we need to make
5341                  * sure there is room to do it, if not we need to commit and try
5342                  * again.
5343                  */
5344                 if (steal_from_global) {
5345                         if (!btrfs_check_space_for_delayed_refs(trans, fs_info))
5346                                 ret = btrfs_block_rsv_migrate(global_rsv, rsv,
5347                                                               min_size, 0);
5348                         else
5349                                 ret = -ENOSPC;
5350                 }
5351
5352                 /*
5353                  * Couldn't steal from the global reserve, we have too much
5354                  * pending stuff built up, commit the transaction and try it
5355                  * again.
5356                  */
5357                 if (ret) {
5358                         ret = btrfs_commit_transaction(trans, root);
5359                         if (ret) {
5360                                 btrfs_orphan_del(NULL, inode);
5361                                 btrfs_free_block_rsv(fs_info, rsv);
5362                                 goto no_delete;
5363                         }
5364                         continue;
5365                 } else {
5366                         steal_from_global = 0;
5367                 }
5368
5369                 trans->block_rsv = rsv;
5370
5371                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
5372                 if (ret != -ENOSPC && ret != -EAGAIN)
5373                         break;
5374
5375                 trans->block_rsv = &fs_info->trans_block_rsv;
5376                 btrfs_end_transaction(trans, root);
5377                 trans = NULL;
5378                 btrfs_btree_balance_dirty(fs_info);
5379         }
5380
5381         btrfs_free_block_rsv(fs_info, rsv);
5382
5383         /*
5384          * Errors here aren't a big deal, it just means we leave orphan items
5385          * in the tree.  They will be cleaned up on the next mount.
5386          */
5387         if (ret == 0) {
5388                 trans->block_rsv = root->orphan_block_rsv;
5389                 btrfs_orphan_del(trans, inode);
5390         } else {
5391                 btrfs_orphan_del(NULL, inode);
5392         }
5393
5394         trans->block_rsv = &fs_info->trans_block_rsv;
5395         if (!(root == fs_info->tree_root ||
5396               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
5397                 btrfs_return_ino(root, btrfs_ino(inode));
5398
5399         btrfs_end_transaction(trans, root);
5400         btrfs_btree_balance_dirty(fs_info);
5401 no_delete:
5402         btrfs_remove_delayed_node(inode);
5403         clear_inode(inode);
5404 }
5405
5406 /*
5407  * this returns the key found in the dir entry in the location pointer.
5408  * If no dir entries were found, location->objectid is 0.
5409  */
5410 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
5411                                struct btrfs_key *location)
5412 {
5413         const char *name = dentry->d_name.name;
5414         int namelen = dentry->d_name.len;
5415         struct btrfs_dir_item *di;
5416         struct btrfs_path *path;
5417         struct btrfs_root *root = BTRFS_I(dir)->root;
5418         int ret = 0;
5419
5420         path = btrfs_alloc_path();
5421         if (!path)
5422                 return -ENOMEM;
5423
5424         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
5425                                     namelen, 0);
5426         if (IS_ERR(di))
5427                 ret = PTR_ERR(di);
5428
5429         if (IS_ERR_OR_NULL(di))
5430                 goto out_err;
5431
5432         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
5433 out:
5434         btrfs_free_path(path);
5435         return ret;
5436 out_err:
5437         location->objectid = 0;
5438         goto out;
5439 }
5440
5441 /*
5442  * when we hit a tree root in a directory, the btrfs part of the inode
5443  * needs to be changed to reflect the root directory of the tree root.  This
5444  * is kind of like crossing a mount point.
5445  */
5446 static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
5447                                     struct inode *dir,
5448                                     struct dentry *dentry,
5449                                     struct btrfs_key *location,
5450                                     struct btrfs_root **sub_root)
5451 {
5452         struct btrfs_path *path;
5453         struct btrfs_root *new_root;
5454         struct btrfs_root_ref *ref;
5455         struct extent_buffer *leaf;
5456         struct btrfs_key key;
5457         int ret;
5458         int err = 0;
5459
5460         path = btrfs_alloc_path();
5461         if (!path) {
5462                 err = -ENOMEM;
5463                 goto out;
5464         }
5465
5466         err = -ENOENT;
5467         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5468         key.type = BTRFS_ROOT_REF_KEY;
5469         key.offset = location->objectid;
5470
5471         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
5472         if (ret) {
5473                 if (ret < 0)
5474                         err = ret;
5475                 goto out;
5476         }
5477
5478         leaf = path->nodes[0];
5479         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5480         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
5481             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5482                 goto out;
5483
5484         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5485                                    (unsigned long)(ref + 1),
5486                                    dentry->d_name.len);
5487         if (ret)
5488                 goto out;
5489
5490         btrfs_release_path(path);
5491
5492         new_root = btrfs_read_fs_root_no_name(fs_info, location);
5493         if (IS_ERR(new_root)) {
5494                 err = PTR_ERR(new_root);
5495                 goto out;
5496         }
5497
5498         *sub_root = new_root;
5499         location->objectid = btrfs_root_dirid(&new_root->root_item);
5500         location->type = BTRFS_INODE_ITEM_KEY;
5501         location->offset = 0;
5502         err = 0;
5503 out:
5504         btrfs_free_path(path);
5505         return err;
5506 }
5507
5508 static void inode_tree_add(struct inode *inode)
5509 {
5510         struct btrfs_root *root = BTRFS_I(inode)->root;
5511         struct btrfs_inode *entry;
5512         struct rb_node **p;
5513         struct rb_node *parent;
5514         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5515         u64 ino = btrfs_ino(inode);
5516
5517         if (inode_unhashed(inode))
5518                 return;
5519         parent = NULL;
5520         spin_lock(&root->inode_lock);
5521         p = &root->inode_tree.rb_node;
5522         while (*p) {
5523                 parent = *p;
5524                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5525
5526                 if (ino < btrfs_ino(&entry->vfs_inode))
5527                         p = &parent->rb_left;
5528                 else if (ino > btrfs_ino(&entry->vfs_inode))
5529                         p = &parent->rb_right;
5530                 else {
5531                         WARN_ON(!(entry->vfs_inode.i_state &
5532                                   (I_WILL_FREE | I_FREEING)));
5533                         rb_replace_node(parent, new, &root->inode_tree);
5534                         RB_CLEAR_NODE(parent);
5535                         spin_unlock(&root->inode_lock);
5536                         return;
5537                 }
5538         }
5539         rb_link_node(new, parent, p);
5540         rb_insert_color(new, &root->inode_tree);
5541         spin_unlock(&root->inode_lock);
5542 }
5543
5544 static void inode_tree_del(struct inode *inode)
5545 {
5546         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5547         struct btrfs_root *root = BTRFS_I(inode)->root;
5548         int empty = 0;
5549
5550         spin_lock(&root->inode_lock);
5551         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5552                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5553                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5554                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5555         }
5556         spin_unlock(&root->inode_lock);
5557
5558         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5559                 synchronize_srcu(&fs_info->subvol_srcu);
5560                 spin_lock(&root->inode_lock);
5561                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5562                 spin_unlock(&root->inode_lock);
5563                 if (empty)
5564                         btrfs_add_dead_root(root);
5565         }
5566 }
5567
5568 void btrfs_invalidate_inodes(struct btrfs_root *root)
5569 {
5570         struct btrfs_fs_info *fs_info = root->fs_info;
5571         struct rb_node *node;
5572         struct rb_node *prev;
5573         struct btrfs_inode *entry;
5574         struct inode *inode;
5575         u64 objectid = 0;
5576
5577         if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
5578                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5579
5580         spin_lock(&root->inode_lock);
5581 again:
5582         node = root->inode_tree.rb_node;
5583         prev = NULL;
5584         while (node) {
5585                 prev = node;
5586                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5587
5588                 if (objectid < btrfs_ino(&entry->vfs_inode))
5589                         node = node->rb_left;
5590                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5591                         node = node->rb_right;
5592                 else
5593                         break;
5594         }
5595         if (!node) {
5596                 while (prev) {
5597                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5598                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5599                                 node = prev;
5600                                 break;
5601                         }
5602                         prev = rb_next(prev);
5603                 }
5604         }
5605         while (node) {
5606                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5607                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5608                 inode = igrab(&entry->vfs_inode);
5609                 if (inode) {
5610                         spin_unlock(&root->inode_lock);
5611                         if (atomic_read(&inode->i_count) > 1)
5612                                 d_prune_aliases(inode);
5613                         /*
5614                          * btrfs_drop_inode will have it removed from
5615                          * the inode cache when its usage count
5616                          * hits zero.
5617                          */
5618                         iput(inode);
5619                         cond_resched();
5620                         spin_lock(&root->inode_lock);
5621                         goto again;
5622                 }
5623
5624                 if (cond_resched_lock(&root->inode_lock))
5625                         goto again;
5626
5627                 node = rb_next(node);
5628         }
5629         spin_unlock(&root->inode_lock);
5630 }
5631
5632 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5633 {
5634         struct btrfs_iget_args *args = p;
5635         inode->i_ino = args->location->objectid;
5636         memcpy(&BTRFS_I(inode)->location, args->location,
5637                sizeof(*args->location));
5638         BTRFS_I(inode)->root = args->root;
5639         return 0;
5640 }
5641
5642 static int btrfs_find_actor(struct inode *inode, void *opaque)
5643 {
5644         struct btrfs_iget_args *args = opaque;
5645         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5646                 args->root == BTRFS_I(inode)->root;
5647 }
5648
5649 static struct inode *btrfs_iget_locked(struct super_block *s,
5650                                        struct btrfs_key *location,
5651                                        struct btrfs_root *root)
5652 {
5653         struct inode *inode;
5654         struct btrfs_iget_args args;
5655         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5656
5657         args.location = location;
5658         args.root = root;
5659
5660         inode = iget5_locked(s, hashval, btrfs_find_actor,
5661                              btrfs_init_locked_inode,
5662                              (void *)&args);
5663         return inode;
5664 }
5665
5666 /* Get an inode object given its location and corresponding root.
5667  * Returns in *is_new if the inode was read from disk
5668  */
5669 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5670                          struct btrfs_root *root, int *new)
5671 {
5672         struct inode *inode;
5673
5674         inode = btrfs_iget_locked(s, location, root);
5675         if (!inode)
5676                 return ERR_PTR(-ENOMEM);
5677
5678         if (inode->i_state & I_NEW) {
5679                 int ret;
5680
5681                 ret = btrfs_read_locked_inode(inode);
5682                 if (!is_bad_inode(inode)) {
5683                         inode_tree_add(inode);
5684                         unlock_new_inode(inode);
5685                         if (new)
5686                                 *new = 1;
5687                 } else {
5688                         unlock_new_inode(inode);
5689                         iput(inode);
5690                         ASSERT(ret < 0);
5691                         inode = ERR_PTR(ret < 0 ? ret : -ESTALE);
5692                 }
5693         }
5694
5695         return inode;
5696 }
5697
5698 static struct inode *new_simple_dir(struct super_block *s,
5699                                     struct btrfs_key *key,
5700                                     struct btrfs_root *root)
5701 {
5702         struct inode *inode = new_inode(s);
5703
5704         if (!inode)
5705                 return ERR_PTR(-ENOMEM);
5706
5707         BTRFS_I(inode)->root = root;
5708         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5709         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5710
5711         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5712         inode->i_op = &btrfs_dir_ro_inode_operations;
5713         inode->i_fop = &simple_dir_operations;
5714         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5715         inode->i_mtime = current_time(inode);
5716         inode->i_atime = inode->i_mtime;
5717         inode->i_ctime = inode->i_mtime;
5718         BTRFS_I(inode)->i_otime = inode->i_mtime;
5719
5720         return inode;
5721 }
5722
5723 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5724 {
5725         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
5726         struct inode *inode;
5727         struct btrfs_root *root = BTRFS_I(dir)->root;
5728         struct btrfs_root *sub_root = root;
5729         struct btrfs_key location;
5730         int index;
5731         int ret = 0;
5732
5733         if (dentry->d_name.len > BTRFS_NAME_LEN)
5734                 return ERR_PTR(-ENAMETOOLONG);
5735
5736         ret = btrfs_inode_by_name(dir, dentry, &location);
5737         if (ret < 0)
5738                 return ERR_PTR(ret);
5739
5740         if (location.objectid == 0)
5741                 return ERR_PTR(-ENOENT);
5742
5743         if (location.type == BTRFS_INODE_ITEM_KEY) {
5744                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5745                 return inode;
5746         }
5747
5748         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5749
5750         index = srcu_read_lock(&fs_info->subvol_srcu);
5751         ret = fixup_tree_root_location(fs_info, dir, dentry,
5752                                        &location, &sub_root);
5753         if (ret < 0) {
5754                 if (ret != -ENOENT)
5755                         inode = ERR_PTR(ret);
5756                 else
5757                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5758         } else {
5759                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5760         }
5761         srcu_read_unlock(&fs_info->subvol_srcu, index);
5762
5763         if (!IS_ERR(inode) && root != sub_root) {
5764                 down_read(&fs_info->cleanup_work_sem);
5765                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5766                         ret = btrfs_orphan_cleanup(sub_root);
5767                 up_read(&fs_info->cleanup_work_sem);
5768                 if (ret) {
5769                         iput(inode);
5770                         inode = ERR_PTR(ret);
5771                 }
5772         }
5773
5774         return inode;
5775 }
5776
5777 static int btrfs_dentry_delete(const struct dentry *dentry)
5778 {
5779         struct btrfs_root *root;
5780         struct inode *inode = d_inode(dentry);
5781
5782         if (!inode && !IS_ROOT(dentry))
5783                 inode = d_inode(dentry->d_parent);
5784
5785         if (inode) {
5786                 root = BTRFS_I(inode)->root;
5787                 if (btrfs_root_refs(&root->root_item) == 0)
5788                         return 1;
5789
5790                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5791                         return 1;
5792         }
5793         return 0;
5794 }
5795
5796 static void btrfs_dentry_release(struct dentry *dentry)
5797 {
5798         kfree(dentry->d_fsdata);
5799 }
5800
5801 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5802                                    unsigned int flags)
5803 {
5804         struct inode *inode;
5805
5806         inode = btrfs_lookup_dentry(dir, dentry);
5807         if (IS_ERR(inode)) {
5808                 if (PTR_ERR(inode) == -ENOENT)
5809                         inode = NULL;
5810                 else
5811                         return ERR_CAST(inode);
5812         }
5813
5814         return d_splice_alias(inode, dentry);
5815 }
5816
5817 unsigned char btrfs_filetype_table[] = {
5818         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5819 };
5820
5821 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5822 {
5823         struct inode *inode = file_inode(file);
5824         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5825         struct btrfs_root *root = BTRFS_I(inode)->root;
5826         struct btrfs_item *item;
5827         struct btrfs_dir_item *di;
5828         struct btrfs_key key;
5829         struct btrfs_key found_key;
5830         struct btrfs_path *path;
5831         struct list_head ins_list;
5832         struct list_head del_list;
5833         int ret;
5834         struct extent_buffer *leaf;
5835         int slot;
5836         unsigned char d_type;
5837         int over = 0;
5838         char tmp_name[32];
5839         char *name_ptr;
5840         int name_len;
5841         bool put = false;
5842         struct btrfs_key location;
5843
5844         if (!dir_emit_dots(file, ctx))
5845                 return 0;
5846
5847         path = btrfs_alloc_path();
5848         if (!path)
5849                 return -ENOMEM;
5850
5851         path->reada = READA_FORWARD;
5852
5853         INIT_LIST_HEAD(&ins_list);
5854         INIT_LIST_HEAD(&del_list);
5855         put = btrfs_readdir_get_delayed_items(inode, &ins_list, &del_list);
5856
5857         key.type = BTRFS_DIR_INDEX_KEY;
5858         key.offset = ctx->pos;
5859         key.objectid = btrfs_ino(inode);
5860
5861         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5862         if (ret < 0)
5863                 goto err;
5864
5865         while (1) {
5866                 leaf = path->nodes[0];
5867                 slot = path->slots[0];
5868                 if (slot >= btrfs_header_nritems(leaf)) {
5869                         ret = btrfs_next_leaf(root, path);
5870                         if (ret < 0)
5871                                 goto err;
5872                         else if (ret > 0)
5873                                 break;
5874                         continue;
5875                 }
5876
5877                 item = btrfs_item_nr(slot);
5878                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5879
5880                 if (found_key.objectid != key.objectid)
5881                         break;
5882                 if (found_key.type != BTRFS_DIR_INDEX_KEY)
5883                         break;
5884                 if (found_key.offset < ctx->pos)
5885                         goto next;
5886                 if (btrfs_should_delete_dir_index(&del_list, found_key.offset))
5887                         goto next;
5888
5889                 ctx->pos = found_key.offset;
5890
5891                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5892                 if (verify_dir_item(fs_info, leaf, di))
5893                         goto next;
5894
5895                 name_len = btrfs_dir_name_len(leaf, di);
5896                 if (name_len <= sizeof(tmp_name)) {
5897                         name_ptr = tmp_name;
5898                 } else {
5899                         name_ptr = kmalloc(name_len, GFP_KERNEL);
5900                         if (!name_ptr) {
5901                                 ret = -ENOMEM;
5902                                 goto err;
5903                         }
5904                 }
5905                 read_extent_buffer(leaf, name_ptr, (unsigned long)(di + 1),
5906                                    name_len);
5907
5908                 d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5909                 btrfs_dir_item_key_to_cpu(leaf, di, &location);
5910
5911                 over = !dir_emit(ctx, name_ptr, name_len, location.objectid,
5912                                  d_type);
5913
5914                 if (name_ptr != tmp_name)
5915                         kfree(name_ptr);
5916
5917                 if (over)
5918                         goto nopos;
5919                 ctx->pos++;
5920 next:
5921                 path->slots[0]++;
5922         }
5923
5924         ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5925         if (ret)
5926                 goto nopos;
5927
5928         /*
5929          * Stop new entries from being returned after we return the last
5930          * entry.
5931          *
5932          * New directory entries are assigned a strictly increasing
5933          * offset.  This means that new entries created during readdir
5934          * are *guaranteed* to be seen in the future by that readdir.
5935          * This has broken buggy programs which operate on names as
5936          * they're returned by readdir.  Until we re-use freed offsets
5937          * we have this hack to stop new entries from being returned
5938          * under the assumption that they'll never reach this huge
5939          * offset.
5940          *
5941          * This is being careful not to overflow 32bit loff_t unless the
5942          * last entry requires it because doing so has broken 32bit apps
5943          * in the past.
5944          */
5945         if (ctx->pos >= INT_MAX)
5946                 ctx->pos = LLONG_MAX;
5947         else
5948                 ctx->pos = INT_MAX;
5949 nopos:
5950         ret = 0;
5951 err:
5952         if (put)
5953                 btrfs_readdir_put_delayed_items(inode, &ins_list, &del_list);
5954         btrfs_free_path(path);
5955         return ret;
5956 }
5957
5958 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5959 {
5960         struct btrfs_root *root = BTRFS_I(inode)->root;
5961         struct btrfs_trans_handle *trans;
5962         int ret = 0;
5963         bool nolock = false;
5964
5965         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5966                 return 0;
5967
5968         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5969                 nolock = true;
5970
5971         if (wbc->sync_mode == WB_SYNC_ALL) {
5972                 if (nolock)
5973                         trans = btrfs_join_transaction_nolock(root);
5974                 else
5975                         trans = btrfs_join_transaction(root);
5976                 if (IS_ERR(trans))
5977                         return PTR_ERR(trans);
5978                 ret = btrfs_commit_transaction(trans, root);
5979         }
5980         return ret;
5981 }
5982
5983 /*
5984  * This is somewhat expensive, updating the tree every time the
5985  * inode changes.  But, it is most likely to find the inode in cache.
5986  * FIXME, needs more benchmarking...there are no reasons other than performance
5987  * to keep or drop this code.
5988  */
5989 static int btrfs_dirty_inode(struct inode *inode)
5990 {
5991         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5992         struct btrfs_root *root = BTRFS_I(inode)->root;
5993         struct btrfs_trans_handle *trans;
5994         int ret;
5995
5996         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5997                 return 0;
5998
5999         trans = btrfs_join_transaction(root);
6000         if (IS_ERR(trans))
6001                 return PTR_ERR(trans);
6002
6003         ret = btrfs_update_inode(trans, root, inode);
6004         if (ret && ret == -ENOSPC) {
6005                 /* whoops, lets try again with the full transaction */
6006                 btrfs_end_transaction(trans, root);
6007                 trans = btrfs_start_transaction(root, 1);
6008                 if (IS_ERR(trans))
6009                         return PTR_ERR(trans);
6010
6011                 ret = btrfs_update_inode(trans, root, inode);
6012         }
6013         btrfs_end_transaction(trans, root);
6014         if (BTRFS_I(inode)->delayed_node)
6015                 btrfs_balance_delayed_items(fs_info);
6016
6017         return ret;
6018 }
6019
6020 /*
6021  * This is a copy of file_update_time.  We need this so we can return error on
6022  * ENOSPC for updating the inode in the case of file write and mmap writes.
6023  */
6024 static int btrfs_update_time(struct inode *inode, struct timespec *now,
6025                              int flags)
6026 {
6027         struct btrfs_root *root = BTRFS_I(inode)->root;
6028
6029         if (btrfs_root_readonly(root))
6030                 return -EROFS;
6031
6032         if (flags & S_VERSION)
6033                 inode_inc_iversion(inode);
6034         if (flags & S_CTIME)
6035                 inode->i_ctime = *now;
6036         if (flags & S_MTIME)
6037                 inode->i_mtime = *now;
6038         if (flags & S_ATIME)
6039                 inode->i_atime = *now;
6040         return btrfs_dirty_inode(inode);
6041 }
6042
6043 /*
6044  * find the highest existing sequence number in a directory
6045  * and then set the in-memory index_cnt variable to reflect
6046  * free sequence numbers
6047  */
6048 static int btrfs_set_inode_index_count(struct inode *inode)
6049 {
6050         struct btrfs_root *root = BTRFS_I(inode)->root;
6051         struct btrfs_key key, found_key;
6052         struct btrfs_path *path;
6053         struct extent_buffer *leaf;
6054         int ret;
6055
6056         key.objectid = btrfs_ino(inode);
6057         key.type = BTRFS_DIR_INDEX_KEY;
6058         key.offset = (u64)-1;
6059
6060         path = btrfs_alloc_path();
6061         if (!path)
6062                 return -ENOMEM;
6063
6064         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6065         if (ret < 0)
6066                 goto out;
6067         /* FIXME: we should be able to handle this */
6068         if (ret == 0)
6069                 goto out;
6070         ret = 0;
6071
6072         /*
6073          * MAGIC NUMBER EXPLANATION:
6074          * since we search a directory based on f_pos we have to start at 2
6075          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6076          * else has to start at 2
6077          */
6078         if (path->slots[0] == 0) {
6079                 BTRFS_I(inode)->index_cnt = 2;
6080                 goto out;
6081         }
6082
6083         path->slots[0]--;
6084
6085         leaf = path->nodes[0];
6086         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6087
6088         if (found_key.objectid != btrfs_ino(inode) ||
6089             found_key.type != BTRFS_DIR_INDEX_KEY) {
6090                 BTRFS_I(inode)->index_cnt = 2;
6091                 goto out;
6092         }
6093
6094         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
6095 out:
6096         btrfs_free_path(path);
6097         return ret;
6098 }
6099
6100 /*
6101  * helper to find a free sequence number in a given directory.  This current
6102  * code is very simple, later versions will do smarter things in the btree
6103  */
6104 int btrfs_set_inode_index(struct inode *dir, u64 *index)
6105 {
6106         int ret = 0;
6107
6108         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
6109                 ret = btrfs_inode_delayed_dir_index_count(dir);
6110                 if (ret) {
6111                         ret = btrfs_set_inode_index_count(dir);
6112                         if (ret)
6113                                 return ret;
6114                 }
6115         }
6116
6117         *index = BTRFS_I(dir)->index_cnt;
6118         BTRFS_I(dir)->index_cnt++;
6119
6120         return ret;
6121 }
6122
6123 static int btrfs_insert_inode_locked(struct inode *inode)
6124 {
6125         struct btrfs_iget_args args;
6126         args.location = &BTRFS_I(inode)->location;
6127         args.root = BTRFS_I(inode)->root;
6128
6129         return insert_inode_locked4(inode,
6130                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6131                    btrfs_find_actor, &args);
6132 }
6133
6134 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6135                                      struct btrfs_root *root,
6136                                      struct inode *dir,
6137                                      const char *name, int name_len,
6138                                      u64 ref_objectid, u64 objectid,
6139                                      umode_t mode, u64 *index)
6140 {
6141         struct btrfs_fs_info *fs_info = root->fs_info;
6142         struct inode *inode;
6143         struct btrfs_inode_item *inode_item;
6144         struct btrfs_key *location;
6145         struct btrfs_path *path;
6146         struct btrfs_inode_ref *ref;
6147         struct btrfs_key key[2];
6148         u32 sizes[2];
6149         int nitems = name ? 2 : 1;
6150         unsigned long ptr;
6151         int ret;
6152
6153         path = btrfs_alloc_path();
6154         if (!path)
6155                 return ERR_PTR(-ENOMEM);
6156
6157         inode = new_inode(fs_info->sb);
6158         if (!inode) {
6159                 btrfs_free_path(path);
6160                 return ERR_PTR(-ENOMEM);
6161         }
6162
6163         /*
6164          * O_TMPFILE, set link count to 0, so that after this point,
6165          * we fill in an inode item with the correct link count.
6166          */
6167         if (!name)
6168                 set_nlink(inode, 0);
6169
6170         /*
6171          * we have to initialize this early, so we can reclaim the inode
6172          * number if we fail afterwards in this function.
6173          */
6174         inode->i_ino = objectid;
6175
6176         if (dir && name) {
6177                 trace_btrfs_inode_request(dir);
6178
6179                 ret = btrfs_set_inode_index(dir, index);
6180                 if (ret) {
6181                         btrfs_free_path(path);
6182                         iput(inode);
6183                         return ERR_PTR(ret);
6184                 }
6185         } else if (dir) {
6186                 *index = 0;
6187         }
6188         /*
6189          * index_cnt is ignored for everything but a dir,
6190          * btrfs_get_inode_index_count has an explanation for the magic
6191          * number
6192          */
6193         BTRFS_I(inode)->index_cnt = 2;
6194         BTRFS_I(inode)->dir_index = *index;
6195         BTRFS_I(inode)->root = root;
6196         BTRFS_I(inode)->generation = trans->transid;
6197         inode->i_generation = BTRFS_I(inode)->generation;
6198
6199         /*
6200          * We could have gotten an inode number from somebody who was fsynced
6201          * and then removed in this same transaction, so let's just set full
6202          * sync since it will be a full sync anyway and this will blow away the
6203          * old info in the log.
6204          */
6205         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6206
6207         key[0].objectid = objectid;
6208         key[0].type = BTRFS_INODE_ITEM_KEY;
6209         key[0].offset = 0;
6210
6211         sizes[0] = sizeof(struct btrfs_inode_item);
6212
6213         if (name) {
6214                 /*
6215                  * Start new inodes with an inode_ref. This is slightly more
6216                  * efficient for small numbers of hard links since they will
6217                  * be packed into one item. Extended refs will kick in if we
6218                  * add more hard links than can fit in the ref item.
6219                  */
6220                 key[1].objectid = objectid;
6221                 key[1].type = BTRFS_INODE_REF_KEY;
6222                 key[1].offset = ref_objectid;
6223
6224                 sizes[1] = name_len + sizeof(*ref);
6225         }
6226
6227         location = &BTRFS_I(inode)->location;
6228         location->objectid = objectid;
6229         location->offset = 0;
6230         location->type = BTRFS_INODE_ITEM_KEY;
6231
6232         ret = btrfs_insert_inode_locked(inode);
6233         if (ret < 0)
6234                 goto fail;
6235
6236         path->leave_spinning = 1;
6237         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6238         if (ret != 0)
6239                 goto fail_unlock;
6240
6241         inode_init_owner(inode, dir, mode);
6242         inode_set_bytes(inode, 0);
6243
6244         inode->i_mtime = current_time(inode);
6245         inode->i_atime = inode->i_mtime;
6246         inode->i_ctime = inode->i_mtime;
6247         BTRFS_I(inode)->i_otime = inode->i_mtime;
6248
6249         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6250                                   struct btrfs_inode_item);
6251         memzero_extent_buffer(path->nodes[0], (unsigned long)inode_item,
6252                              sizeof(*inode_item));
6253         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6254
6255         if (name) {
6256                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6257                                      struct btrfs_inode_ref);
6258                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6259                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6260                 ptr = (unsigned long)(ref + 1);
6261                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6262         }
6263
6264         btrfs_mark_buffer_dirty(path->nodes[0]);
6265         btrfs_free_path(path);
6266
6267         btrfs_inherit_iflags(inode, dir);
6268
6269         if (S_ISREG(mode)) {
6270                 if (btrfs_test_opt(fs_info, NODATASUM))
6271                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6272                 if (btrfs_test_opt(fs_info, NODATACOW))
6273                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6274                                 BTRFS_INODE_NODATASUM;
6275         }
6276
6277         inode_tree_add(inode);
6278
6279         trace_btrfs_inode_new(inode);
6280         btrfs_set_inode_last_trans(trans, inode);
6281
6282         btrfs_update_root_times(trans, root);
6283
6284         ret = btrfs_inode_inherit_props(trans, inode, dir);
6285         if (ret)
6286                 btrfs_err(fs_info,
6287                           "error inheriting props for ino %llu (root %llu): %d",
6288                           btrfs_ino(inode), root->root_key.objectid, ret);
6289
6290         return inode;
6291
6292 fail_unlock:
6293         unlock_new_inode(inode);
6294 fail:
6295         if (dir && name)
6296                 BTRFS_I(dir)->index_cnt--;
6297         btrfs_free_path(path);
6298         iput(inode);
6299         return ERR_PTR(ret);
6300 }
6301
6302 static inline u8 btrfs_inode_type(struct inode *inode)
6303 {
6304         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6305 }
6306
6307 /*
6308  * utility function to add 'inode' into 'parent_inode' with
6309  * a give name and a given sequence number.
6310  * if 'add_backref' is true, also insert a backref from the
6311  * inode to the parent directory.
6312  */
6313 int btrfs_add_link(struct btrfs_trans_handle *trans,
6314                    struct inode *parent_inode, struct inode *inode,
6315                    const char *name, int name_len, int add_backref, u64 index)
6316 {
6317         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6318         int ret = 0;
6319         struct btrfs_key key;
6320         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
6321         u64 ino = btrfs_ino(inode);
6322         u64 parent_ino = btrfs_ino(parent_inode);
6323
6324         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6325                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
6326         } else {
6327                 key.objectid = ino;
6328                 key.type = BTRFS_INODE_ITEM_KEY;
6329                 key.offset = 0;
6330         }
6331
6332         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6333                 ret = btrfs_add_root_ref(trans, fs_info, key.objectid,
6334                                          root->root_key.objectid, parent_ino,
6335                                          index, name, name_len);
6336         } else if (add_backref) {
6337                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6338                                              parent_ino, index);
6339         }
6340
6341         /* Nothing to clean up yet */
6342         if (ret)
6343                 return ret;
6344
6345         ret = btrfs_insert_dir_item(trans, root, name, name_len,
6346                                     parent_inode, &key,
6347                                     btrfs_inode_type(inode), index);
6348         if (ret == -EEXIST || ret == -EOVERFLOW)
6349                 goto fail_dir_item;
6350         else if (ret) {
6351                 btrfs_abort_transaction(trans, ret);
6352                 return ret;
6353         }
6354
6355         btrfs_i_size_write(parent_inode, parent_inode->i_size +
6356                            name_len * 2);
6357         inode_inc_iversion(parent_inode);
6358         parent_inode->i_mtime = parent_inode->i_ctime =
6359                 current_time(parent_inode);
6360         ret = btrfs_update_inode(trans, root, parent_inode);
6361         if (ret)
6362                 btrfs_abort_transaction(trans, ret);
6363         return ret;
6364
6365 fail_dir_item:
6366         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6367                 u64 local_index;
6368                 int err;
6369                 err = btrfs_del_root_ref(trans, fs_info, key.objectid,
6370                                          root->root_key.objectid, parent_ino,
6371                                          &local_index, name, name_len);
6372
6373         } else if (add_backref) {
6374                 u64 local_index;
6375                 int err;
6376
6377                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6378                                           ino, parent_ino, &local_index);
6379         }
6380         return ret;
6381 }
6382
6383 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6384                             struct inode *dir, struct dentry *dentry,
6385                             struct inode *inode, int backref, u64 index)
6386 {
6387         int err = btrfs_add_link(trans, dir, inode,
6388                                  dentry->d_name.name, dentry->d_name.len,
6389                                  backref, index);
6390         if (err > 0)
6391                 err = -EEXIST;
6392         return err;
6393 }
6394
6395 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6396                         umode_t mode, dev_t rdev)
6397 {
6398         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6399         struct btrfs_trans_handle *trans;
6400         struct btrfs_root *root = BTRFS_I(dir)->root;
6401         struct inode *inode = NULL;
6402         int err;
6403         int drop_inode = 0;
6404         u64 objectid;
6405         u64 index = 0;
6406
6407         /*
6408          * 2 for inode item and ref
6409          * 2 for dir items
6410          * 1 for xattr if selinux is on
6411          */
6412         trans = btrfs_start_transaction(root, 5);
6413         if (IS_ERR(trans))
6414                 return PTR_ERR(trans);
6415
6416         err = btrfs_find_free_ino(root, &objectid);
6417         if (err)
6418                 goto out_unlock;
6419
6420         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6421                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6422                                 mode, &index);
6423         if (IS_ERR(inode)) {
6424                 err = PTR_ERR(inode);
6425                 goto out_unlock;
6426         }
6427
6428         /*
6429         * If the active LSM wants to access the inode during
6430         * d_instantiate it needs these. Smack checks to see
6431         * if the filesystem supports xattrs by looking at the
6432         * ops vector.
6433         */
6434         inode->i_op = &btrfs_special_inode_operations;
6435         init_special_inode(inode, inode->i_mode, rdev);
6436
6437         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6438         if (err)
6439                 goto out_unlock_inode;
6440
6441         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6442         if (err) {
6443                 goto out_unlock_inode;
6444         } else {
6445                 btrfs_update_inode(trans, root, inode);
6446                 unlock_new_inode(inode);
6447                 d_instantiate(dentry, inode);
6448         }
6449
6450 out_unlock:
6451         btrfs_end_transaction(trans, root);
6452         btrfs_balance_delayed_items(fs_info);
6453         btrfs_btree_balance_dirty(fs_info);
6454         if (drop_inode) {
6455                 inode_dec_link_count(inode);
6456                 iput(inode);
6457         }
6458         return err;
6459
6460 out_unlock_inode:
6461         drop_inode = 1;
6462         unlock_new_inode(inode);
6463         goto out_unlock;
6464
6465 }
6466
6467 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6468                         umode_t mode, bool excl)
6469 {
6470         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6471         struct btrfs_trans_handle *trans;
6472         struct btrfs_root *root = BTRFS_I(dir)->root;
6473         struct inode *inode = NULL;
6474         int drop_inode_on_err = 0;
6475         int err;
6476         u64 objectid;
6477         u64 index = 0;
6478
6479         /*
6480          * 2 for inode item and ref
6481          * 2 for dir items
6482          * 1 for xattr if selinux is on
6483          */
6484         trans = btrfs_start_transaction(root, 5);
6485         if (IS_ERR(trans))
6486                 return PTR_ERR(trans);
6487
6488         err = btrfs_find_free_ino(root, &objectid);
6489         if (err)
6490                 goto out_unlock;
6491
6492         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6493                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6494                                 mode, &index);
6495         if (IS_ERR(inode)) {
6496                 err = PTR_ERR(inode);
6497                 goto out_unlock;
6498         }
6499         drop_inode_on_err = 1;
6500         /*
6501         * If the active LSM wants to access the inode during
6502         * d_instantiate it needs these. Smack checks to see
6503         * if the filesystem supports xattrs by looking at the
6504         * ops vector.
6505         */
6506         inode->i_fop = &btrfs_file_operations;
6507         inode->i_op = &btrfs_file_inode_operations;
6508         inode->i_mapping->a_ops = &btrfs_aops;
6509
6510         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6511         if (err)
6512                 goto out_unlock_inode;
6513
6514         err = btrfs_update_inode(trans, root, inode);
6515         if (err)
6516                 goto out_unlock_inode;
6517
6518         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6519         if (err)
6520                 goto out_unlock_inode;
6521
6522         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6523         unlock_new_inode(inode);
6524         d_instantiate(dentry, inode);
6525
6526 out_unlock:
6527         btrfs_end_transaction(trans, root);
6528         if (err && drop_inode_on_err) {
6529                 inode_dec_link_count(inode);
6530                 iput(inode);
6531         }
6532         btrfs_balance_delayed_items(fs_info);
6533         btrfs_btree_balance_dirty(fs_info);
6534         return err;
6535
6536 out_unlock_inode:
6537         unlock_new_inode(inode);
6538         goto out_unlock;
6539
6540 }
6541
6542 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6543                       struct dentry *dentry)
6544 {
6545         struct btrfs_trans_handle *trans = NULL;
6546         struct btrfs_root *root = BTRFS_I(dir)->root;
6547         struct inode *inode = d_inode(old_dentry);
6548         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6549         u64 index;
6550         int err;
6551         int drop_inode = 0;
6552
6553         /* do not allow sys_link's with other subvols of the same device */
6554         if (root->objectid != BTRFS_I(inode)->root->objectid)
6555                 return -EXDEV;
6556
6557         if (inode->i_nlink >= BTRFS_LINK_MAX)
6558                 return -EMLINK;
6559
6560         err = btrfs_set_inode_index(dir, &index);
6561         if (err)
6562                 goto fail;
6563
6564         /*
6565          * 2 items for inode and inode ref
6566          * 2 items for dir items
6567          * 1 item for parent inode
6568          */
6569         trans = btrfs_start_transaction(root, 5);
6570         if (IS_ERR(trans)) {
6571                 err = PTR_ERR(trans);
6572                 trans = NULL;
6573                 goto fail;
6574         }
6575
6576         /* There are several dir indexes for this inode, clear the cache. */
6577         BTRFS_I(inode)->dir_index = 0ULL;
6578         inc_nlink(inode);
6579         inode_inc_iversion(inode);
6580         inode->i_ctime = current_time(inode);
6581         ihold(inode);
6582         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6583
6584         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6585
6586         if (err) {
6587                 drop_inode = 1;
6588         } else {
6589                 struct dentry *parent = dentry->d_parent;
6590                 err = btrfs_update_inode(trans, root, inode);
6591                 if (err)
6592                         goto fail;
6593                 if (inode->i_nlink == 1) {
6594                         /*
6595                          * If new hard link count is 1, it's a file created
6596                          * with open(2) O_TMPFILE flag.
6597                          */
6598                         err = btrfs_orphan_del(trans, inode);
6599                         if (err)
6600                                 goto fail;
6601                 }
6602                 d_instantiate(dentry, inode);
6603                 btrfs_log_new_name(trans, inode, NULL, parent);
6604         }
6605
6606         btrfs_balance_delayed_items(fs_info);
6607 fail:
6608         if (trans)
6609                 btrfs_end_transaction(trans, root);
6610         if (drop_inode) {
6611                 inode_dec_link_count(inode);
6612                 iput(inode);
6613         }
6614         btrfs_btree_balance_dirty(fs_info);
6615         return err;
6616 }
6617
6618 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6619 {
6620         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6621         struct inode *inode = NULL;
6622         struct btrfs_trans_handle *trans;
6623         struct btrfs_root *root = BTRFS_I(dir)->root;
6624         int err = 0;
6625         int drop_on_err = 0;
6626         u64 objectid = 0;
6627         u64 index = 0;
6628
6629         /*
6630          * 2 items for inode and ref
6631          * 2 items for dir items
6632          * 1 for xattr if selinux is on
6633          */
6634         trans = btrfs_start_transaction(root, 5);
6635         if (IS_ERR(trans))
6636                 return PTR_ERR(trans);
6637
6638         err = btrfs_find_free_ino(root, &objectid);
6639         if (err)
6640                 goto out_fail;
6641
6642         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6643                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6644                                 S_IFDIR | mode, &index);
6645         if (IS_ERR(inode)) {
6646                 err = PTR_ERR(inode);
6647                 goto out_fail;
6648         }
6649
6650         drop_on_err = 1;
6651         /* these must be set before we unlock the inode */
6652         inode->i_op = &btrfs_dir_inode_operations;
6653         inode->i_fop = &btrfs_dir_file_operations;
6654
6655         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6656         if (err)
6657                 goto out_fail_inode;
6658
6659         btrfs_i_size_write(inode, 0);
6660         err = btrfs_update_inode(trans, root, inode);
6661         if (err)
6662                 goto out_fail_inode;
6663
6664         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6665                              dentry->d_name.len, 0, index);
6666         if (err)
6667                 goto out_fail_inode;
6668
6669         d_instantiate(dentry, inode);
6670         /*
6671          * mkdir is special.  We're unlocking after we call d_instantiate
6672          * to avoid a race with nfsd calling d_instantiate.
6673          */
6674         unlock_new_inode(inode);
6675         drop_on_err = 0;
6676
6677 out_fail:
6678         btrfs_end_transaction(trans, root);
6679         if (drop_on_err) {
6680                 inode_dec_link_count(inode);
6681                 iput(inode);
6682         }
6683         btrfs_balance_delayed_items(fs_info);
6684         btrfs_btree_balance_dirty(fs_info);
6685         return err;
6686
6687 out_fail_inode:
6688         unlock_new_inode(inode);
6689         goto out_fail;
6690 }
6691
6692 /* Find next extent map of a given extent map, caller needs to ensure locks */
6693 static struct extent_map *next_extent_map(struct extent_map *em)
6694 {
6695         struct rb_node *next;
6696
6697         next = rb_next(&em->rb_node);
6698         if (!next)
6699                 return NULL;
6700         return container_of(next, struct extent_map, rb_node);
6701 }
6702
6703 static struct extent_map *prev_extent_map(struct extent_map *em)
6704 {
6705         struct rb_node *prev;
6706
6707         prev = rb_prev(&em->rb_node);
6708         if (!prev)
6709                 return NULL;
6710         return container_of(prev, struct extent_map, rb_node);
6711 }
6712
6713 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6714  * the existing extent is the nearest extent to map_start,
6715  * and an extent that you want to insert, deal with overlap and insert
6716  * the best fitted new extent into the tree.
6717  */
6718 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6719                                 struct extent_map *existing,
6720                                 struct extent_map *em,
6721                                 u64 map_start)
6722 {
6723         struct extent_map *prev;
6724         struct extent_map *next;
6725         u64 start;
6726         u64 end;
6727         u64 start_diff;
6728
6729         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6730
6731         if (existing->start > map_start) {
6732                 next = existing;
6733                 prev = prev_extent_map(next);
6734         } else {
6735                 prev = existing;
6736                 next = next_extent_map(prev);
6737         }
6738
6739         start = prev ? extent_map_end(prev) : em->start;
6740         start = max_t(u64, start, em->start);
6741         end = next ? next->start : extent_map_end(em);
6742         end = min_t(u64, end, extent_map_end(em));
6743         start_diff = start - em->start;
6744         em->start = start;
6745         em->len = end - start;
6746         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6747             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6748                 em->block_start += start_diff;
6749                 em->block_len -= start_diff;
6750         }
6751         return add_extent_mapping(em_tree, em, 0);
6752 }
6753
6754 static noinline int uncompress_inline(struct btrfs_path *path,
6755                                       struct page *page,
6756                                       size_t pg_offset, u64 extent_offset,
6757                                       struct btrfs_file_extent_item *item)
6758 {
6759         int ret;
6760         struct extent_buffer *leaf = path->nodes[0];
6761         char *tmp;
6762         size_t max_size;
6763         unsigned long inline_size;
6764         unsigned long ptr;
6765         int compress_type;
6766
6767         WARN_ON(pg_offset != 0);
6768         compress_type = btrfs_file_extent_compression(leaf, item);
6769         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6770         inline_size = btrfs_file_extent_inline_item_len(leaf,
6771                                         btrfs_item_nr(path->slots[0]));
6772         tmp = kmalloc(inline_size, GFP_NOFS);
6773         if (!tmp)
6774                 return -ENOMEM;
6775         ptr = btrfs_file_extent_inline_start(item);
6776
6777         read_extent_buffer(leaf, tmp, ptr, inline_size);
6778
6779         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6780         ret = btrfs_decompress(compress_type, tmp, page,
6781                                extent_offset, inline_size, max_size);
6782         kfree(tmp);
6783         return ret;
6784 }
6785
6786 /*
6787  * a bit scary, this does extent mapping from logical file offset to the disk.
6788  * the ugly parts come from merging extents from the disk with the in-ram
6789  * representation.  This gets more complex because of the data=ordered code,
6790  * where the in-ram extents might be locked pending data=ordered completion.
6791  *
6792  * This also copies inline extents directly into the page.
6793  */
6794
6795 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6796                                     size_t pg_offset, u64 start, u64 len,
6797                                     int create)
6798 {
6799         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6800         int ret;
6801         int err = 0;
6802         u64 extent_start = 0;
6803         u64 extent_end = 0;
6804         u64 objectid = btrfs_ino(inode);
6805         u32 found_type;
6806         struct btrfs_path *path = NULL;
6807         struct btrfs_root *root = BTRFS_I(inode)->root;
6808         struct btrfs_file_extent_item *item;
6809         struct extent_buffer *leaf;
6810         struct btrfs_key found_key;
6811         struct extent_map *em = NULL;
6812         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6813         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6814         struct btrfs_trans_handle *trans = NULL;
6815         const bool new_inline = !page || create;
6816
6817 again:
6818         read_lock(&em_tree->lock);
6819         em = lookup_extent_mapping(em_tree, start, len);
6820         if (em)
6821                 em->bdev = fs_info->fs_devices->latest_bdev;
6822         read_unlock(&em_tree->lock);
6823
6824         if (em) {
6825                 if (em->start > start || em->start + em->len <= start)
6826                         free_extent_map(em);
6827                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6828                         free_extent_map(em);
6829                 else
6830                         goto out;
6831         }
6832         em = alloc_extent_map();
6833         if (!em) {
6834                 err = -ENOMEM;
6835                 goto out;
6836         }
6837         em->bdev = fs_info->fs_devices->latest_bdev;
6838         em->start = EXTENT_MAP_HOLE;
6839         em->orig_start = EXTENT_MAP_HOLE;
6840         em->len = (u64)-1;
6841         em->block_len = (u64)-1;
6842
6843         if (!path) {
6844                 path = btrfs_alloc_path();
6845                 if (!path) {
6846                         err = -ENOMEM;
6847                         goto out;
6848                 }
6849                 /*
6850                  * Chances are we'll be called again, so go ahead and do
6851                  * readahead
6852                  */
6853                 path->reada = READA_FORWARD;
6854         }
6855
6856         ret = btrfs_lookup_file_extent(trans, root, path,
6857                                        objectid, start, trans != NULL);
6858         if (ret < 0) {
6859                 err = ret;
6860                 goto out;
6861         }
6862
6863         if (ret != 0) {
6864                 if (path->slots[0] == 0)
6865                         goto not_found;
6866                 path->slots[0]--;
6867         }
6868
6869         leaf = path->nodes[0];
6870         item = btrfs_item_ptr(leaf, path->slots[0],
6871                               struct btrfs_file_extent_item);
6872         /* are we inside the extent that was found? */
6873         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6874         found_type = found_key.type;
6875         if (found_key.objectid != objectid ||
6876             found_type != BTRFS_EXTENT_DATA_KEY) {
6877                 /*
6878                  * If we backup past the first extent we want to move forward
6879                  * and see if there is an extent in front of us, otherwise we'll
6880                  * say there is a hole for our whole search range which can
6881                  * cause problems.
6882                  */
6883                 extent_end = start;
6884                 goto next;
6885         }
6886
6887         found_type = btrfs_file_extent_type(leaf, item);
6888         extent_start = found_key.offset;
6889         if (found_type == BTRFS_FILE_EXTENT_REG ||
6890             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6891                 extent_end = extent_start +
6892                        btrfs_file_extent_num_bytes(leaf, item);
6893         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6894                 size_t size;
6895                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6896                 extent_end = ALIGN(extent_start + size,
6897                                    fs_info->sectorsize);
6898         }
6899 next:
6900         if (start >= extent_end) {
6901                 path->slots[0]++;
6902                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6903                         ret = btrfs_next_leaf(root, path);
6904                         if (ret < 0) {
6905                                 err = ret;
6906                                 goto out;
6907                         }
6908                         if (ret > 0)
6909                                 goto not_found;
6910                         leaf = path->nodes[0];
6911                 }
6912                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6913                 if (found_key.objectid != objectid ||
6914                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6915                         goto not_found;
6916                 if (start + len <= found_key.offset)
6917                         goto not_found;
6918                 if (start > found_key.offset)
6919                         goto next;
6920                 em->start = start;
6921                 em->orig_start = start;
6922                 em->len = found_key.offset - start;
6923                 goto not_found_em;
6924         }
6925
6926         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6927
6928         if (found_type == BTRFS_FILE_EXTENT_REG ||
6929             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6930                 goto insert;
6931         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6932                 unsigned long ptr;
6933                 char *map;
6934                 size_t size;
6935                 size_t extent_offset;
6936                 size_t copy_size;
6937
6938                 if (new_inline)
6939                         goto out;
6940
6941                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6942                 extent_offset = page_offset(page) + pg_offset - extent_start;
6943                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
6944                                   size - extent_offset);
6945                 em->start = extent_start + extent_offset;
6946                 em->len = ALIGN(copy_size, fs_info->sectorsize);
6947                 em->orig_block_len = em->len;
6948                 em->orig_start = em->start;
6949                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6950                 if (create == 0 && !PageUptodate(page)) {
6951                         if (btrfs_file_extent_compression(leaf, item) !=
6952                             BTRFS_COMPRESS_NONE) {
6953                                 ret = uncompress_inline(path, page, pg_offset,
6954                                                         extent_offset, item);
6955                                 if (ret) {
6956                                         err = ret;
6957                                         goto out;
6958                                 }
6959                         } else {
6960                                 map = kmap(page);
6961                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6962                                                    copy_size);
6963                                 if (pg_offset + copy_size < PAGE_SIZE) {
6964                                         memset(map + pg_offset + copy_size, 0,
6965                                                PAGE_SIZE - pg_offset -
6966                                                copy_size);
6967                                 }
6968                                 kunmap(page);
6969                         }
6970                         flush_dcache_page(page);
6971                 } else if (create && PageUptodate(page)) {
6972                         BUG();
6973                         if (!trans) {
6974                                 kunmap(page);
6975                                 free_extent_map(em);
6976                                 em = NULL;
6977
6978                                 btrfs_release_path(path);
6979                                 trans = btrfs_join_transaction(root);
6980
6981                                 if (IS_ERR(trans))
6982                                         return ERR_CAST(trans);
6983                                 goto again;
6984                         }
6985                         map = kmap(page);
6986                         write_extent_buffer(leaf, map + pg_offset, ptr,
6987                                             copy_size);
6988                         kunmap(page);
6989                         btrfs_mark_buffer_dirty(leaf);
6990                 }
6991                 set_extent_uptodate(io_tree, em->start,
6992                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6993                 goto insert;
6994         }
6995 not_found:
6996         em->start = start;
6997         em->orig_start = start;
6998         em->len = len;
6999 not_found_em:
7000         em->block_start = EXTENT_MAP_HOLE;
7001         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
7002 insert:
7003         btrfs_release_path(path);
7004         if (em->start > start || extent_map_end(em) <= start) {
7005                 btrfs_err(fs_info,
7006                           "bad extent! em: [%llu %llu] passed [%llu %llu]",
7007                           em->start, em->len, start, len);
7008                 err = -EIO;
7009                 goto out;
7010         }
7011
7012         err = 0;
7013         write_lock(&em_tree->lock);
7014         ret = add_extent_mapping(em_tree, em, 0);
7015         /* it is possible that someone inserted the extent into the tree
7016          * while we had the lock dropped.  It is also possible that
7017          * an overlapping map exists in the tree
7018          */
7019         if (ret == -EEXIST) {
7020                 struct extent_map *existing;
7021
7022                 ret = 0;
7023
7024                 existing = search_extent_mapping(em_tree, start, len);
7025                 /*
7026                  * existing will always be non-NULL, since there must be
7027                  * extent causing the -EEXIST.
7028                  */
7029                 if (existing->start == em->start &&
7030                     extent_map_end(existing) >= extent_map_end(em) &&
7031                     em->block_start == existing->block_start) {
7032                         /*
7033                          * The existing extent map already encompasses the
7034                          * entire extent map we tried to add.
7035                          */
7036                         free_extent_map(em);
7037                         em = existing;
7038                         err = 0;
7039
7040                 } else if (start >= extent_map_end(existing) ||
7041                     start <= existing->start) {
7042                         /*
7043                          * The existing extent map is the one nearest to
7044                          * the [start, start + len) range which overlaps
7045                          */
7046                         err = merge_extent_mapping(em_tree, existing,
7047                                                    em, start);
7048                         free_extent_map(existing);
7049                         if (err) {
7050                                 free_extent_map(em);
7051                                 em = NULL;
7052                         }
7053                 } else {
7054                         free_extent_map(em);
7055                         em = existing;
7056                         err = 0;
7057                 }
7058         }
7059         write_unlock(&em_tree->lock);
7060 out:
7061
7062         trace_btrfs_get_extent(root, em);
7063
7064         btrfs_free_path(path);
7065         if (trans) {
7066                 ret = btrfs_end_transaction(trans, root);
7067                 if (!err)
7068                         err = ret;
7069         }
7070         if (err) {
7071                 free_extent_map(em);
7072                 return ERR_PTR(err);
7073         }
7074         BUG_ON(!em); /* Error is always set */
7075         return em;
7076 }
7077
7078 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
7079                                            size_t pg_offset, u64 start, u64 len,
7080                                            int create)
7081 {
7082         struct extent_map *em;
7083         struct extent_map *hole_em = NULL;
7084         u64 range_start = start;
7085         u64 end;
7086         u64 found;
7087         u64 found_end;
7088         int err = 0;
7089
7090         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
7091         if (IS_ERR(em))
7092                 return em;
7093         if (em) {
7094                 /*
7095                  * if our em maps to
7096                  * -  a hole or
7097                  * -  a pre-alloc extent,
7098                  * there might actually be delalloc bytes behind it.
7099                  */
7100                 if (em->block_start != EXTENT_MAP_HOLE &&
7101                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7102                         return em;
7103                 else
7104                         hole_em = em;
7105         }
7106
7107         /* check to see if we've wrapped (len == -1 or similar) */
7108         end = start + len;
7109         if (end < start)
7110                 end = (u64)-1;
7111         else
7112                 end -= 1;
7113
7114         em = NULL;
7115
7116         /* ok, we didn't find anything, lets look for delalloc */
7117         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
7118                                  end, len, EXTENT_DELALLOC, 1);
7119         found_end = range_start + found;
7120         if (found_end < range_start)
7121                 found_end = (u64)-1;
7122
7123         /*
7124          * we didn't find anything useful, return
7125          * the original results from get_extent()
7126          */
7127         if (range_start > end || found_end <= start) {
7128                 em = hole_em;
7129                 hole_em = NULL;
7130                 goto out;
7131         }
7132
7133         /* adjust the range_start to make sure it doesn't
7134          * go backwards from the start they passed in
7135          */
7136         range_start = max(start, range_start);
7137         found = found_end - range_start;
7138
7139         if (found > 0) {
7140                 u64 hole_start = start;
7141                 u64 hole_len = len;
7142
7143                 em = alloc_extent_map();
7144                 if (!em) {
7145                         err = -ENOMEM;
7146                         goto out;
7147                 }
7148                 /*
7149                  * when btrfs_get_extent can't find anything it
7150                  * returns one huge hole
7151                  *
7152                  * make sure what it found really fits our range, and
7153                  * adjust to make sure it is based on the start from
7154                  * the caller
7155                  */
7156                 if (hole_em) {
7157                         u64 calc_end = extent_map_end(hole_em);
7158
7159                         if (calc_end <= start || (hole_em->start > end)) {
7160                                 free_extent_map(hole_em);
7161                                 hole_em = NULL;
7162                         } else {
7163                                 hole_start = max(hole_em->start, start);
7164                                 hole_len = calc_end - hole_start;
7165                         }
7166                 }
7167                 em->bdev = NULL;
7168                 if (hole_em && range_start > hole_start) {
7169                         /* our hole starts before our delalloc, so we
7170                          * have to return just the parts of the hole
7171                          * that go until  the delalloc starts
7172                          */
7173                         em->len = min(hole_len,
7174                                       range_start - hole_start);
7175                         em->start = hole_start;
7176                         em->orig_start = hole_start;
7177                         /*
7178                          * don't adjust block start at all,
7179                          * it is fixed at EXTENT_MAP_HOLE
7180                          */
7181                         em->block_start = hole_em->block_start;
7182                         em->block_len = hole_len;
7183                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7184                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7185                 } else {
7186                         em->start = range_start;
7187                         em->len = found;
7188                         em->orig_start = range_start;
7189                         em->block_start = EXTENT_MAP_DELALLOC;
7190                         em->block_len = found;
7191                 }
7192         } else if (hole_em) {
7193                 return hole_em;
7194         }
7195 out:
7196
7197         free_extent_map(hole_em);
7198         if (err) {
7199                 free_extent_map(em);
7200                 return ERR_PTR(err);
7201         }
7202         return em;
7203 }
7204
7205 static struct extent_map *btrfs_create_dio_extent(struct inode *inode,
7206                                                   const u64 start,
7207                                                   const u64 len,
7208                                                   const u64 orig_start,
7209                                                   const u64 block_start,
7210                                                   const u64 block_len,
7211                                                   const u64 orig_block_len,
7212                                                   const u64 ram_bytes,
7213                                                   const int type)
7214 {
7215         struct extent_map *em = NULL;
7216         int ret;
7217
7218         down_read(&BTRFS_I(inode)->dio_sem);
7219         if (type != BTRFS_ORDERED_NOCOW) {
7220                 em = create_pinned_em(inode, start, len, orig_start,
7221                                       block_start, block_len, orig_block_len,
7222                                       ram_bytes, type);
7223                 if (IS_ERR(em))
7224                         goto out;
7225         }
7226         ret = btrfs_add_ordered_extent_dio(inode, start, block_start,
7227                                            len, block_len, type);
7228         if (ret) {
7229                 if (em) {
7230                         free_extent_map(em);
7231                         btrfs_drop_extent_cache(inode, start,
7232                                                 start + len - 1, 0);
7233                 }
7234                 em = ERR_PTR(ret);
7235         }
7236  out:
7237         up_read(&BTRFS_I(inode)->dio_sem);
7238
7239         return em;
7240 }
7241
7242 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7243                                                   u64 start, u64 len)
7244 {
7245         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7246         struct btrfs_root *root = BTRFS_I(inode)->root;
7247         struct extent_map *em;
7248         struct btrfs_key ins;
7249         u64 alloc_hint;
7250         int ret;
7251
7252         alloc_hint = get_extent_allocation_hint(inode, start, len);
7253         ret = btrfs_reserve_extent(root, len, len, fs_info->sectorsize,
7254                                    0, alloc_hint, &ins, 1, 1);
7255         if (ret)
7256                 return ERR_PTR(ret);
7257
7258         em = btrfs_create_dio_extent(inode, start, ins.offset, start,
7259                                      ins.objectid, ins.offset, ins.offset,
7260                                      ins.offset, 0);
7261         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
7262         if (IS_ERR(em))
7263                 btrfs_free_reserved_extent(fs_info, ins.objectid,
7264                                            ins.offset, 1);
7265
7266         return em;
7267 }
7268
7269 /*
7270  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7271  * block must be cow'd
7272  */
7273 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7274                               u64 *orig_start, u64 *orig_block_len,
7275                               u64 *ram_bytes)
7276 {
7277         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7278         struct btrfs_trans_handle *trans;
7279         struct btrfs_path *path;
7280         int ret;
7281         struct extent_buffer *leaf;
7282         struct btrfs_root *root = BTRFS_I(inode)->root;
7283         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7284         struct btrfs_file_extent_item *fi;
7285         struct btrfs_key key;
7286         u64 disk_bytenr;
7287         u64 backref_offset;
7288         u64 extent_end;
7289         u64 num_bytes;
7290         int slot;
7291         int found_type;
7292         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7293
7294         path = btrfs_alloc_path();
7295         if (!path)
7296                 return -ENOMEM;
7297
7298         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
7299                                        offset, 0);
7300         if (ret < 0)
7301                 goto out;
7302
7303         slot = path->slots[0];
7304         if (ret == 1) {
7305                 if (slot == 0) {
7306                         /* can't find the item, must cow */
7307                         ret = 0;
7308                         goto out;
7309                 }
7310                 slot--;
7311         }
7312         ret = 0;
7313         leaf = path->nodes[0];
7314         btrfs_item_key_to_cpu(leaf, &key, slot);
7315         if (key.objectid != btrfs_ino(inode) ||
7316             key.type != BTRFS_EXTENT_DATA_KEY) {
7317                 /* not our file or wrong item type, must cow */
7318                 goto out;
7319         }
7320
7321         if (key.offset > offset) {
7322                 /* Wrong offset, must cow */
7323                 goto out;
7324         }
7325
7326         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7327         found_type = btrfs_file_extent_type(leaf, fi);
7328         if (found_type != BTRFS_FILE_EXTENT_REG &&
7329             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7330                 /* not a regular extent, must cow */
7331                 goto out;
7332         }
7333
7334         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7335                 goto out;
7336
7337         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7338         if (extent_end <= offset)
7339                 goto out;
7340
7341         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7342         if (disk_bytenr == 0)
7343                 goto out;
7344
7345         if (btrfs_file_extent_compression(leaf, fi) ||
7346             btrfs_file_extent_encryption(leaf, fi) ||
7347             btrfs_file_extent_other_encoding(leaf, fi))
7348                 goto out;
7349
7350         backref_offset = btrfs_file_extent_offset(leaf, fi);
7351
7352         if (orig_start) {
7353                 *orig_start = key.offset - backref_offset;
7354                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7355                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7356         }
7357
7358         if (btrfs_extent_readonly(fs_info, disk_bytenr))
7359                 goto out;
7360
7361         num_bytes = min(offset + *len, extent_end) - offset;
7362         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7363                 u64 range_end;
7364
7365                 range_end = round_up(offset + num_bytes,
7366                                      root->fs_info->sectorsize) - 1;
7367                 ret = test_range_bit(io_tree, offset, range_end,
7368                                      EXTENT_DELALLOC, 0, NULL);
7369                 if (ret) {
7370                         ret = -EAGAIN;
7371                         goto out;
7372                 }
7373         }
7374
7375         btrfs_release_path(path);
7376
7377         /*
7378          * look for other files referencing this extent, if we
7379          * find any we must cow
7380          */
7381         trans = btrfs_join_transaction(root);
7382         if (IS_ERR(trans)) {
7383                 ret = 0;
7384                 goto out;
7385         }
7386
7387         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
7388                                     key.offset - backref_offset, disk_bytenr);
7389         btrfs_end_transaction(trans, root);
7390         if (ret) {
7391                 ret = 0;
7392                 goto out;
7393         }
7394
7395         /*
7396          * adjust disk_bytenr and num_bytes to cover just the bytes
7397          * in this extent we are about to write.  If there
7398          * are any csums in that range we have to cow in order
7399          * to keep the csums correct
7400          */
7401         disk_bytenr += backref_offset;
7402         disk_bytenr += offset - key.offset;
7403         if (csum_exist_in_range(fs_info, disk_bytenr, num_bytes))
7404                 goto out;
7405         /*
7406          * all of the above have passed, it is safe to overwrite this extent
7407          * without cow
7408          */
7409         *len = num_bytes;
7410         ret = 1;
7411 out:
7412         btrfs_free_path(path);
7413         return ret;
7414 }
7415
7416 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
7417 {
7418         struct radix_tree_root *root = &inode->i_mapping->page_tree;
7419         int found = false;
7420         void **pagep = NULL;
7421         struct page *page = NULL;
7422         int start_idx;
7423         int end_idx;
7424
7425         start_idx = start >> PAGE_SHIFT;
7426
7427         /*
7428          * end is the last byte in the last page.  end == start is legal
7429          */
7430         end_idx = end >> PAGE_SHIFT;
7431
7432         rcu_read_lock();
7433
7434         /* Most of the code in this while loop is lifted from
7435          * find_get_page.  It's been modified to begin searching from a
7436          * page and return just the first page found in that range.  If the
7437          * found idx is less than or equal to the end idx then we know that
7438          * a page exists.  If no pages are found or if those pages are
7439          * outside of the range then we're fine (yay!) */
7440         while (page == NULL &&
7441                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
7442                 page = radix_tree_deref_slot(pagep);
7443                 if (unlikely(!page))
7444                         break;
7445
7446                 if (radix_tree_exception(page)) {
7447                         if (radix_tree_deref_retry(page)) {
7448                                 page = NULL;
7449                                 continue;
7450                         }
7451                         /*
7452                          * Otherwise, shmem/tmpfs must be storing a swap entry
7453                          * here as an exceptional entry: so return it without
7454                          * attempting to raise page count.
7455                          */
7456                         page = NULL;
7457                         break; /* TODO: Is this relevant for this use case? */
7458                 }
7459
7460                 if (!page_cache_get_speculative(page)) {
7461                         page = NULL;
7462                         continue;
7463                 }
7464
7465                 /*
7466                  * Has the page moved?
7467                  * This is part of the lockless pagecache protocol. See
7468                  * include/linux/pagemap.h for details.
7469                  */
7470                 if (unlikely(page != *pagep)) {
7471                         put_page(page);
7472                         page = NULL;
7473                 }
7474         }
7475
7476         if (page) {
7477                 if (page->index <= end_idx)
7478                         found = true;
7479                 put_page(page);
7480         }
7481
7482         rcu_read_unlock();
7483         return found;
7484 }
7485
7486 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7487                               struct extent_state **cached_state, int writing)
7488 {
7489         struct btrfs_ordered_extent *ordered;
7490         int ret = 0;
7491
7492         while (1) {
7493                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7494                                  cached_state);
7495                 /*
7496                  * We're concerned with the entire range that we're going to be
7497                  * doing DIO to, so we need to make sure there's no ordered
7498                  * extents in this range.
7499                  */
7500                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
7501                                                      lockend - lockstart + 1);
7502
7503                 /*
7504                  * We need to make sure there are no buffered pages in this
7505                  * range either, we could have raced between the invalidate in
7506                  * generic_file_direct_write and locking the extent.  The
7507                  * invalidate needs to happen so that reads after a write do not
7508                  * get stale data.
7509                  */
7510                 if (!ordered &&
7511                     (!writing ||
7512                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
7513                         break;
7514
7515                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7516                                      cached_state, GFP_NOFS);
7517
7518                 if (ordered) {
7519                         /*
7520                          * If we are doing a DIO read and the ordered extent we
7521                          * found is for a buffered write, we can not wait for it
7522                          * to complete and retry, because if we do so we can
7523                          * deadlock with concurrent buffered writes on page
7524                          * locks. This happens only if our DIO read covers more
7525                          * than one extent map, if at this point has already
7526                          * created an ordered extent for a previous extent map
7527                          * and locked its range in the inode's io tree, and a
7528                          * concurrent write against that previous extent map's
7529                          * range and this range started (we unlock the ranges
7530                          * in the io tree only when the bios complete and
7531                          * buffered writes always lock pages before attempting
7532                          * to lock range in the io tree).
7533                          */
7534                         if (writing ||
7535                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
7536                                 btrfs_start_ordered_extent(inode, ordered, 1);
7537                         else
7538                                 ret = -ENOTBLK;
7539                         btrfs_put_ordered_extent(ordered);
7540                 } else {
7541                         /*
7542                          * We could trigger writeback for this range (and wait
7543                          * for it to complete) and then invalidate the pages for
7544                          * this range (through invalidate_inode_pages2_range()),
7545                          * but that can lead us to a deadlock with a concurrent
7546                          * call to readpages() (a buffered read or a defrag call
7547                          * triggered a readahead) on a page lock due to an
7548                          * ordered dio extent we created before but did not have
7549                          * yet a corresponding bio submitted (whence it can not
7550                          * complete), which makes readpages() wait for that
7551                          * ordered extent to complete while holding a lock on
7552                          * that page.
7553                          */
7554                         ret = -ENOTBLK;
7555                 }
7556
7557                 if (ret)
7558                         break;
7559
7560                 cond_resched();
7561         }
7562
7563         return ret;
7564 }
7565
7566 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
7567                                            u64 len, u64 orig_start,
7568                                            u64 block_start, u64 block_len,
7569                                            u64 orig_block_len, u64 ram_bytes,
7570                                            int type)
7571 {
7572         struct extent_map_tree *em_tree;
7573         struct extent_map *em;
7574         struct btrfs_root *root = BTRFS_I(inode)->root;
7575         int ret;
7576
7577         em_tree = &BTRFS_I(inode)->extent_tree;
7578         em = alloc_extent_map();
7579         if (!em)
7580                 return ERR_PTR(-ENOMEM);
7581
7582         em->start = start;
7583         em->orig_start = orig_start;
7584         em->mod_start = start;
7585         em->mod_len = len;
7586         em->len = len;
7587         em->block_len = block_len;
7588         em->block_start = block_start;
7589         em->bdev = root->fs_info->fs_devices->latest_bdev;
7590         em->orig_block_len = orig_block_len;
7591         em->ram_bytes = ram_bytes;
7592         em->generation = -1;
7593         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7594         if (type == BTRFS_ORDERED_PREALLOC)
7595                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7596
7597         do {
7598                 btrfs_drop_extent_cache(inode, em->start,
7599                                 em->start + em->len - 1, 0);
7600                 write_lock(&em_tree->lock);
7601                 ret = add_extent_mapping(em_tree, em, 1);
7602                 write_unlock(&em_tree->lock);
7603         } while (ret == -EEXIST);
7604
7605         if (ret) {
7606                 free_extent_map(em);
7607                 return ERR_PTR(ret);
7608         }
7609
7610         return em;
7611 }
7612
7613 static void adjust_dio_outstanding_extents(struct inode *inode,
7614                                            struct btrfs_dio_data *dio_data,
7615                                            const u64 len)
7616 {
7617         unsigned num_extents;
7618
7619         num_extents = (unsigned) div64_u64(len + BTRFS_MAX_EXTENT_SIZE - 1,
7620                                            BTRFS_MAX_EXTENT_SIZE);
7621         /*
7622          * If we have an outstanding_extents count still set then we're
7623          * within our reservation, otherwise we need to adjust our inode
7624          * counter appropriately.
7625          */
7626         if (dio_data->outstanding_extents) {
7627                 dio_data->outstanding_extents -= num_extents;
7628         } else {
7629                 spin_lock(&BTRFS_I(inode)->lock);
7630                 BTRFS_I(inode)->outstanding_extents += num_extents;
7631                 spin_unlock(&BTRFS_I(inode)->lock);
7632         }
7633 }
7634
7635 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7636                                    struct buffer_head *bh_result, int create)
7637 {
7638         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7639         struct extent_map *em;
7640         struct extent_state *cached_state = NULL;
7641         struct btrfs_dio_data *dio_data = NULL;
7642         u64 start = iblock << inode->i_blkbits;
7643         u64 lockstart, lockend;
7644         u64 len = bh_result->b_size;
7645         int unlock_bits = EXTENT_LOCKED;
7646         int ret = 0;
7647
7648         if (create)
7649                 unlock_bits |= EXTENT_DIRTY;
7650         else
7651                 len = min_t(u64, len, fs_info->sectorsize);
7652
7653         lockstart = start;
7654         lockend = start + len - 1;
7655
7656         if (current->journal_info) {
7657                 /*
7658                  * Need to pull our outstanding extents and set journal_info to NULL so
7659                  * that anything that needs to check if there's a transaction doesn't get
7660                  * confused.
7661                  */
7662                 dio_data = current->journal_info;
7663                 current->journal_info = NULL;
7664         }
7665
7666         /*
7667          * If this errors out it's because we couldn't invalidate pagecache for
7668          * this range and we need to fallback to buffered.
7669          */
7670         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7671                                create)) {
7672                 ret = -ENOTBLK;
7673                 goto err;
7674         }
7675
7676         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
7677         if (IS_ERR(em)) {
7678                 ret = PTR_ERR(em);
7679                 goto unlock_err;
7680         }
7681
7682         /*
7683          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7684          * io.  INLINE is special, and we could probably kludge it in here, but
7685          * it's still buffered so for safety lets just fall back to the generic
7686          * buffered path.
7687          *
7688          * For COMPRESSED we _have_ to read the entire extent in so we can
7689          * decompress it, so there will be buffering required no matter what we
7690          * do, so go ahead and fallback to buffered.
7691          *
7692          * We return -ENOTBLK because that's what makes DIO go ahead and go back
7693          * to buffered IO.  Don't blame me, this is the price we pay for using
7694          * the generic code.
7695          */
7696         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7697             em->block_start == EXTENT_MAP_INLINE) {
7698                 free_extent_map(em);
7699                 ret = -ENOTBLK;
7700                 goto unlock_err;
7701         }
7702
7703         /* Just a good old fashioned hole, return */
7704         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7705                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7706                 free_extent_map(em);
7707                 goto unlock_err;
7708         }
7709
7710         /*
7711          * We don't allocate a new extent in the following cases
7712          *
7713          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7714          * existing extent.
7715          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7716          * just use the extent.
7717          *
7718          */
7719         if (!create) {
7720                 len = min(len, em->len - (start - em->start));
7721                 lockstart = start + len;
7722                 goto unlock;
7723         }
7724
7725         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7726             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7727              em->block_start != EXTENT_MAP_HOLE)) {
7728                 int type;
7729                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7730
7731                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7732                         type = BTRFS_ORDERED_PREALLOC;
7733                 else
7734                         type = BTRFS_ORDERED_NOCOW;
7735                 len = min(len, em->len - (start - em->start));
7736                 block_start = em->block_start + (start - em->start);
7737
7738                 if (can_nocow_extent(inode, start, &len, &orig_start,
7739                                      &orig_block_len, &ram_bytes) == 1 &&
7740                     btrfs_inc_nocow_writers(fs_info, block_start)) {
7741                         struct extent_map *em2;
7742
7743                         em2 = btrfs_create_dio_extent(inode, start, len,
7744                                                       orig_start, block_start,
7745                                                       len, orig_block_len,
7746                                                       ram_bytes, type);
7747                         btrfs_dec_nocow_writers(fs_info, block_start);
7748                         if (type == BTRFS_ORDERED_PREALLOC) {
7749                                 free_extent_map(em);
7750                                 em = em2;
7751                         }
7752                         if (em2 && IS_ERR(em2)) {
7753                                 ret = PTR_ERR(em2);
7754                                 goto unlock_err;
7755                         }
7756                         /*
7757                          * For inode marked NODATACOW or extent marked PREALLOC,
7758                          * use the existing or preallocated extent, so does not
7759                          * need to adjust btrfs_space_info's bytes_may_use.
7760                          */
7761                         btrfs_free_reserved_data_space_noquota(inode,
7762                                         start, len);
7763                         goto unlock;
7764                 }
7765         }
7766
7767         /*
7768          * this will cow the extent, if em is within [start, len], then
7769          * probably we've found a preallocated/existing extent, let's
7770          * give it a chance to use preallocated space.
7771          */
7772         len = min_t(u64, bh_result->b_size, em->len - (start - em->start));
7773         len = ALIGN(len, fs_info->sectorsize);
7774         free_extent_map(em);
7775         em = btrfs_new_extent_direct(inode, start, len);
7776         if (IS_ERR(em)) {
7777                 ret = PTR_ERR(em);
7778                 goto unlock_err;
7779         }
7780         len = min(len, em->len - (start - em->start));
7781 unlock:
7782         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7783                 inode->i_blkbits;
7784         bh_result->b_size = len;
7785         bh_result->b_bdev = em->bdev;
7786         set_buffer_mapped(bh_result);
7787         if (create) {
7788                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7789                         set_buffer_new(bh_result);
7790
7791                 /*
7792                  * Need to update the i_size under the extent lock so buffered
7793                  * readers will get the updated i_size when we unlock.
7794                  */
7795                 if (start + len > i_size_read(inode))
7796                         i_size_write(inode, start + len);
7797
7798                 adjust_dio_outstanding_extents(inode, dio_data, len);
7799                 WARN_ON(dio_data->reserve < len);
7800                 dio_data->reserve -= len;
7801                 dio_data->unsubmitted_oe_range_end = start + len;
7802                 current->journal_info = dio_data;
7803         }
7804
7805         /*
7806          * In the case of write we need to clear and unlock the entire range,
7807          * in the case of read we need to unlock only the end area that we
7808          * aren't using if there is any left over space.
7809          */
7810         if (lockstart < lockend) {
7811                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7812                                  lockend, unlock_bits, 1, 0,
7813                                  &cached_state, GFP_NOFS);
7814         } else {
7815                 free_extent_state(cached_state);
7816         }
7817
7818         free_extent_map(em);
7819
7820         return 0;
7821
7822 unlock_err:
7823         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7824                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7825 err:
7826         if (dio_data)
7827                 current->journal_info = dio_data;
7828         /*
7829          * Compensate the delalloc release we do in btrfs_direct_IO() when we
7830          * write less data then expected, so that we don't underflow our inode's
7831          * outstanding extents counter.
7832          */
7833         if (create && dio_data)
7834                 adjust_dio_outstanding_extents(inode, dio_data, len);
7835
7836         return ret;
7837 }
7838
7839 static inline int submit_dio_repair_bio(struct inode *inode, struct bio *bio,
7840                                         int mirror_num)
7841 {
7842         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7843         int ret;
7844
7845         BUG_ON(bio_op(bio) == REQ_OP_WRITE);
7846
7847         bio_get(bio);
7848
7849         ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DIO_REPAIR);
7850         if (ret)
7851                 goto err;
7852
7853         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
7854 err:
7855         bio_put(bio);
7856         return ret;
7857 }
7858
7859 static int btrfs_check_dio_repairable(struct inode *inode,
7860                                       struct bio *failed_bio,
7861                                       struct io_failure_record *failrec,
7862                                       int failed_mirror)
7863 {
7864         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7865         int num_copies;
7866
7867         num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
7868         if (num_copies == 1) {
7869                 /*
7870                  * we only have a single copy of the data, so don't bother with
7871                  * all the retry and error correction code that follows. no
7872                  * matter what the error is, it is very likely to persist.
7873                  */
7874                 btrfs_debug(fs_info,
7875                         "Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
7876                         num_copies, failrec->this_mirror, failed_mirror);
7877                 return 0;
7878         }
7879
7880         failrec->failed_mirror = failed_mirror;
7881         failrec->this_mirror++;
7882         if (failrec->this_mirror == failed_mirror)
7883                 failrec->this_mirror++;
7884
7885         if (failrec->this_mirror > num_copies) {
7886                 btrfs_debug(fs_info,
7887                         "Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
7888                         num_copies, failrec->this_mirror, failed_mirror);
7889                 return 0;
7890         }
7891
7892         return 1;
7893 }
7894
7895 static int dio_read_error(struct inode *inode, struct bio *failed_bio,
7896                         struct page *page, unsigned int pgoff,
7897                         u64 start, u64 end, int failed_mirror,
7898                         bio_end_io_t *repair_endio, void *repair_arg)
7899 {
7900         struct io_failure_record *failrec;
7901         struct bio *bio;
7902         int isector;
7903         int read_mode;
7904         int ret;
7905
7906         BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
7907
7908         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7909         if (ret)
7910                 return ret;
7911
7912         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7913                                          failed_mirror);
7914         if (!ret) {
7915                 free_io_failure(inode, failrec);
7916                 return -EIO;
7917         }
7918
7919         if ((failed_bio->bi_vcnt > 1)
7920                 || (failed_bio->bi_io_vec->bv_len
7921                         > btrfs_inode_sectorsize(inode)))
7922                 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
7923         else
7924                 read_mode = READ_SYNC;
7925
7926         isector = start - btrfs_io_bio(failed_bio)->logical;
7927         isector >>= inode->i_sb->s_blocksize_bits;
7928         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7929                                 pgoff, isector, repair_endio, repair_arg);
7930         if (!bio) {
7931                 free_io_failure(inode, failrec);
7932                 return -EIO;
7933         }
7934         bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
7935
7936         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7937                     "Repair DIO Read Error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d\n",
7938                     read_mode, failrec->this_mirror, failrec->in_validation);
7939
7940         ret = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
7941         if (ret) {
7942                 free_io_failure(inode, failrec);
7943                 bio_put(bio);
7944         }
7945
7946         return ret;
7947 }
7948
7949 struct btrfs_retry_complete {
7950         struct completion done;
7951         struct inode *inode;
7952         u64 start;
7953         int uptodate;
7954 };
7955
7956 static void btrfs_retry_endio_nocsum(struct bio *bio)
7957 {
7958         struct btrfs_retry_complete *done = bio->bi_private;
7959         struct inode *inode;
7960         struct bio_vec *bvec;
7961         int i;
7962
7963         if (bio->bi_error)
7964                 goto end;
7965
7966         ASSERT(bio->bi_vcnt == 1);
7967         inode = bio->bi_io_vec->bv_page->mapping->host;
7968         ASSERT(bio->bi_io_vec->bv_len == btrfs_inode_sectorsize(inode));
7969
7970         done->uptodate = 1;
7971         bio_for_each_segment_all(bvec, bio, i)
7972                 clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
7973 end:
7974         complete(&done->done);
7975         bio_put(bio);
7976 }
7977
7978 static int __btrfs_correct_data_nocsum(struct inode *inode,
7979                                        struct btrfs_io_bio *io_bio)
7980 {
7981         struct btrfs_fs_info *fs_info;
7982         struct bio_vec *bvec;
7983         struct btrfs_retry_complete done;
7984         u64 start;
7985         unsigned int pgoff;
7986         u32 sectorsize;
7987         int nr_sectors;
7988         int i;
7989         int ret;
7990
7991         fs_info = BTRFS_I(inode)->root->fs_info;
7992         sectorsize = fs_info->sectorsize;
7993
7994         start = io_bio->logical;
7995         done.inode = inode;
7996
7997         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7998                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
7999                 pgoff = bvec->bv_offset;
8000
8001 next_block_or_try_again:
8002                 done.uptodate = 0;
8003                 done.start = start;
8004                 init_completion(&done.done);
8005
8006                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
8007                                 pgoff, start, start + sectorsize - 1,
8008                                 io_bio->mirror_num,
8009                                 btrfs_retry_endio_nocsum, &done);
8010                 if (ret)
8011                         return ret;
8012
8013                 wait_for_completion(&done.done);
8014
8015                 if (!done.uptodate) {
8016                         /* We might have another mirror, so try again */
8017                         goto next_block_or_try_again;
8018                 }
8019
8020                 start += sectorsize;
8021
8022                 if (nr_sectors--) {
8023                         pgoff += sectorsize;
8024                         goto next_block_or_try_again;
8025                 }
8026         }
8027
8028         return 0;
8029 }
8030
8031 static void btrfs_retry_endio(struct bio *bio)
8032 {
8033         struct btrfs_retry_complete *done = bio->bi_private;
8034         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8035         struct inode *inode;
8036         struct bio_vec *bvec;
8037         u64 start;
8038         int uptodate;
8039         int ret;
8040         int i;
8041
8042         if (bio->bi_error)
8043                 goto end;
8044
8045         uptodate = 1;
8046
8047         start = done->start;
8048
8049         ASSERT(bio->bi_vcnt == 1);
8050         inode = bio->bi_io_vec->bv_page->mapping->host;
8051         ASSERT(bio->bi_io_vec->bv_len == btrfs_inode_sectorsize(inode));
8052
8053         bio_for_each_segment_all(bvec, bio, i) {
8054                 ret = __readpage_endio_check(done->inode, io_bio, i,
8055                                         bvec->bv_page, bvec->bv_offset,
8056                                         done->start, bvec->bv_len);
8057                 if (!ret)
8058                         clean_io_failure(done->inode, done->start,
8059                                         bvec->bv_page, bvec->bv_offset);
8060                 else
8061                         uptodate = 0;
8062         }
8063
8064         done->uptodate = uptodate;
8065 end:
8066         complete(&done->done);
8067         bio_put(bio);
8068 }
8069
8070 static int __btrfs_subio_endio_read(struct inode *inode,
8071                                     struct btrfs_io_bio *io_bio, int err)
8072 {
8073         struct btrfs_fs_info *fs_info;
8074         struct bio_vec *bvec;
8075         struct btrfs_retry_complete done;
8076         u64 start;
8077         u64 offset = 0;
8078         u32 sectorsize;
8079         int nr_sectors;
8080         unsigned int pgoff;
8081         int csum_pos;
8082         int i;
8083         int ret;
8084
8085         fs_info = BTRFS_I(inode)->root->fs_info;
8086         sectorsize = fs_info->sectorsize;
8087
8088         err = 0;
8089         start = io_bio->logical;
8090         done.inode = inode;
8091
8092         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
8093                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
8094
8095                 pgoff = bvec->bv_offset;
8096 next_block:
8097                 csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
8098                 ret = __readpage_endio_check(inode, io_bio, csum_pos,
8099                                         bvec->bv_page, pgoff, start,
8100                                         sectorsize);
8101                 if (likely(!ret))
8102                         goto next;
8103 try_again:
8104                 done.uptodate = 0;
8105                 done.start = start;
8106                 init_completion(&done.done);
8107
8108                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
8109                                 pgoff, start, start + sectorsize - 1,
8110                                 io_bio->mirror_num,
8111                                 btrfs_retry_endio, &done);
8112                 if (ret) {
8113                         err = ret;
8114                         goto next;
8115                 }
8116
8117                 wait_for_completion(&done.done);
8118
8119                 if (!done.uptodate) {
8120                         /* We might have another mirror, so try again */
8121                         goto try_again;
8122                 }
8123 next:
8124                 offset += sectorsize;
8125                 start += sectorsize;
8126
8127                 ASSERT(nr_sectors);
8128
8129                 if (--nr_sectors) {
8130                         pgoff += sectorsize;
8131                         goto next_block;
8132                 }
8133         }
8134
8135         return err;
8136 }
8137
8138 static int btrfs_subio_endio_read(struct inode *inode,
8139                                   struct btrfs_io_bio *io_bio, int err)
8140 {
8141         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8142
8143         if (skip_csum) {
8144                 if (unlikely(err))
8145                         return __btrfs_correct_data_nocsum(inode, io_bio);
8146                 else
8147                         return 0;
8148         } else {
8149                 return __btrfs_subio_endio_read(inode, io_bio, err);
8150         }
8151 }
8152
8153 static void btrfs_endio_direct_read(struct bio *bio)
8154 {
8155         struct btrfs_dio_private *dip = bio->bi_private;
8156         struct inode *inode = dip->inode;
8157         struct bio *dio_bio;
8158         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8159         int err = bio->bi_error;
8160
8161         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
8162                 err = btrfs_subio_endio_read(inode, io_bio, err);
8163
8164         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
8165                       dip->logical_offset + dip->bytes - 1);
8166         dio_bio = dip->dio_bio;
8167
8168         kfree(dip);
8169
8170         dio_bio->bi_error = bio->bi_error;
8171         dio_end_io(dio_bio, bio->bi_error);
8172
8173         if (io_bio->end_io)
8174                 io_bio->end_io(io_bio, err);
8175         bio_put(bio);
8176 }
8177
8178 static void btrfs_endio_direct_write_update_ordered(struct inode *inode,
8179                                                     const u64 offset,
8180                                                     const u64 bytes,
8181                                                     const int uptodate)
8182 {
8183         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8184         struct btrfs_ordered_extent *ordered = NULL;
8185         u64 ordered_offset = offset;
8186         u64 ordered_bytes = bytes;
8187         int ret;
8188
8189 again:
8190         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
8191                                                    &ordered_offset,
8192                                                    ordered_bytes,
8193                                                    uptodate);
8194         if (!ret)
8195                 goto out_test;
8196
8197         btrfs_init_work(&ordered->work, btrfs_endio_write_helper,
8198                         finish_ordered_fn, NULL, NULL);
8199         btrfs_queue_work(fs_info->endio_write_workers, &ordered->work);
8200 out_test:
8201         /*
8202          * our bio might span multiple ordered extents.  If we haven't
8203          * completed the accounting for the whole dio, go back and try again
8204          */
8205         if (ordered_offset < offset + bytes) {
8206                 ordered_bytes = offset + bytes - ordered_offset;
8207                 ordered = NULL;
8208                 goto again;
8209         }
8210 }
8211
8212 static void btrfs_endio_direct_write(struct bio *bio)
8213 {
8214         struct btrfs_dio_private *dip = bio->bi_private;
8215         struct bio *dio_bio = dip->dio_bio;
8216
8217         btrfs_endio_direct_write_update_ordered(dip->inode,
8218                                                 dip->logical_offset,
8219                                                 dip->bytes,
8220                                                 !bio->bi_error);
8221
8222         kfree(dip);
8223
8224         dio_bio->bi_error = bio->bi_error;
8225         dio_end_io(dio_bio, bio->bi_error);
8226         bio_put(bio);
8227 }
8228
8229 static int __btrfs_submit_bio_start_direct_io(struct inode *inode,
8230                                     struct bio *bio, int mirror_num,
8231                                     unsigned long bio_flags, u64 offset)
8232 {
8233         int ret;
8234         ret = btrfs_csum_one_bio(inode, bio, offset, 1);
8235         BUG_ON(ret); /* -ENOMEM */
8236         return 0;
8237 }
8238
8239 static void btrfs_end_dio_bio(struct bio *bio)
8240 {
8241         struct btrfs_dio_private *dip = bio->bi_private;
8242         int err = bio->bi_error;
8243
8244         if (err)
8245                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8246                            "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
8247                            btrfs_ino(dip->inode), bio_op(bio), bio->bi_opf,
8248                            (unsigned long long)bio->bi_iter.bi_sector,
8249                            bio->bi_iter.bi_size, err);
8250
8251         if (dip->subio_endio)
8252                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8253
8254         if (err) {
8255                 dip->errors = 1;
8256
8257                 /*
8258                  * before atomic variable goto zero, we must make sure
8259                  * dip->errors is perceived to be set.
8260                  */
8261                 smp_mb__before_atomic();
8262         }
8263
8264         /* if there are more bios still pending for this dio, just exit */
8265         if (!atomic_dec_and_test(&dip->pending_bios))
8266                 goto out;
8267
8268         if (dip->errors) {
8269                 bio_io_error(dip->orig_bio);
8270         } else {
8271                 dip->dio_bio->bi_error = 0;
8272                 bio_endio(dip->orig_bio);
8273         }
8274 out:
8275         bio_put(bio);
8276 }
8277
8278 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
8279                                        u64 first_sector, gfp_t gfp_flags)
8280 {
8281         struct bio *bio;
8282         bio = btrfs_bio_alloc(bdev, first_sector, BIO_MAX_PAGES, gfp_flags);
8283         if (bio)
8284                 bio_associate_current(bio);
8285         return bio;
8286 }
8287
8288 static inline int btrfs_lookup_and_bind_dio_csum(struct inode *inode,
8289                                                  struct btrfs_dio_private *dip,
8290                                                  struct bio *bio,
8291                                                  u64 file_offset)
8292 {
8293         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8294         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8295         int ret;
8296
8297         /*
8298          * We load all the csum data we need when we submit
8299          * the first bio to reduce the csum tree search and
8300          * contention.
8301          */
8302         if (dip->logical_offset == file_offset) {
8303                 ret = btrfs_lookup_bio_sums_dio(inode, dip->orig_bio,
8304                                                 file_offset);
8305                 if (ret)
8306                         return ret;
8307         }
8308
8309         if (bio == dip->orig_bio)
8310                 return 0;
8311
8312         file_offset -= dip->logical_offset;
8313         file_offset >>= inode->i_sb->s_blocksize_bits;
8314         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8315
8316         return 0;
8317 }
8318
8319 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
8320                                          u64 file_offset, int skip_sum,
8321                                          int async_submit)
8322 {
8323         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8324         struct btrfs_dio_private *dip = bio->bi_private;
8325         bool write = bio_op(bio) == REQ_OP_WRITE;
8326         int ret;
8327
8328         if (async_submit)
8329                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8330
8331         bio_get(bio);
8332
8333         if (!write) {
8334                 ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
8335                 if (ret)
8336                         goto err;
8337         }
8338
8339         if (skip_sum)
8340                 goto map;
8341
8342         if (write && async_submit) {
8343                 ret = btrfs_wq_submit_bio(fs_info, inode, bio, 0, 0,
8344                                           file_offset,
8345                                           __btrfs_submit_bio_start_direct_io,
8346                                           __btrfs_submit_bio_done);
8347                 goto err;
8348         } else if (write) {
8349                 /*
8350                  * If we aren't doing async submit, calculate the csum of the
8351                  * bio now.
8352                  */
8353                 ret = btrfs_csum_one_bio(inode, bio, file_offset, 1);
8354                 if (ret)
8355                         goto err;
8356         } else {
8357                 ret = btrfs_lookup_and_bind_dio_csum(inode, dip, bio,
8358                                                      file_offset);
8359                 if (ret)
8360                         goto err;
8361         }
8362 map:
8363         ret = btrfs_map_bio(fs_info, bio, 0, async_submit);
8364 err:
8365         bio_put(bio);
8366         return ret;
8367 }
8368
8369 static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip,
8370                                     int skip_sum)
8371 {
8372         struct inode *inode = dip->inode;
8373         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8374         struct btrfs_root *root = BTRFS_I(inode)->root;
8375         struct bio *bio;
8376         struct bio *orig_bio = dip->orig_bio;
8377         struct bio_vec *bvec;
8378         u64 start_sector = orig_bio->bi_iter.bi_sector;
8379         u64 file_offset = dip->logical_offset;
8380         u64 submit_len = 0;
8381         u64 map_length;
8382         u32 blocksize = fs_info->sectorsize;
8383         int async_submit = 0;
8384         int nr_sectors;
8385         int ret;
8386         int i, j;
8387
8388         map_length = orig_bio->bi_iter.bi_size;
8389         ret = btrfs_map_block(fs_info, btrfs_op(orig_bio), start_sector << 9,
8390                               &map_length, NULL, 0);
8391         if (ret)
8392                 return -EIO;
8393
8394         if (map_length >= orig_bio->bi_iter.bi_size) {
8395                 bio = orig_bio;
8396                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8397                 goto submit;
8398         }
8399
8400         /* async crcs make it difficult to collect full stripe writes. */
8401         if (btrfs_get_alloc_profile(root, 1) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8402                 async_submit = 0;
8403         else
8404                 async_submit = 1;
8405
8406         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
8407         if (!bio)
8408                 return -ENOMEM;
8409
8410         bio_set_op_attrs(bio, bio_op(orig_bio), bio_flags(orig_bio));
8411         bio->bi_private = dip;
8412         bio->bi_end_io = btrfs_end_dio_bio;
8413         btrfs_io_bio(bio)->logical = file_offset;
8414         atomic_inc(&dip->pending_bios);
8415
8416         bio_for_each_segment_all(bvec, orig_bio, j) {
8417                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
8418                 i = 0;
8419 next_block:
8420                 if (unlikely(map_length < submit_len + blocksize ||
8421                     bio_add_page(bio, bvec->bv_page, blocksize,
8422                             bvec->bv_offset + (i * blocksize)) < blocksize)) {
8423                         /*
8424                          * inc the count before we submit the bio so
8425                          * we know the end IO handler won't happen before
8426                          * we inc the count. Otherwise, the dip might get freed
8427                          * before we're done setting it up
8428                          */
8429                         atomic_inc(&dip->pending_bios);
8430                         ret = __btrfs_submit_dio_bio(bio, inode,
8431                                                      file_offset, skip_sum,
8432                                                      async_submit);
8433                         if (ret) {
8434                                 bio_put(bio);
8435                                 atomic_dec(&dip->pending_bios);
8436                                 goto out_err;
8437                         }
8438
8439                         start_sector += submit_len >> 9;
8440                         file_offset += submit_len;
8441
8442                         submit_len = 0;
8443
8444                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
8445                                                   start_sector, GFP_NOFS);
8446                         if (!bio)
8447                                 goto out_err;
8448                         bio_set_op_attrs(bio, bio_op(orig_bio),
8449                                          bio_flags(orig_bio));
8450                         bio->bi_private = dip;
8451                         bio->bi_end_io = btrfs_end_dio_bio;
8452                         btrfs_io_bio(bio)->logical = file_offset;
8453
8454                         map_length = orig_bio->bi_iter.bi_size;
8455                         ret = btrfs_map_block(fs_info, btrfs_op(orig_bio),
8456                                               start_sector << 9,
8457                                               &map_length, NULL, 0);
8458                         if (ret) {
8459                                 bio_put(bio);
8460                                 goto out_err;
8461                         }
8462
8463                         goto next_block;
8464                 } else {
8465                         submit_len += blocksize;
8466                         if (--nr_sectors) {
8467                                 i++;
8468                                 goto next_block;
8469                         }
8470                 }
8471         }
8472
8473 submit:
8474         ret = __btrfs_submit_dio_bio(bio, inode, file_offset, skip_sum,
8475                                      async_submit);
8476         if (!ret)
8477                 return 0;
8478
8479         bio_put(bio);
8480 out_err:
8481         dip->errors = 1;
8482         /*
8483          * before atomic variable goto zero, we must
8484          * make sure dip->errors is perceived to be set.
8485          */
8486         smp_mb__before_atomic();
8487         if (atomic_dec_and_test(&dip->pending_bios))
8488                 bio_io_error(dip->orig_bio);
8489
8490         /* bio_end_io() will handle error, so we needn't return it */
8491         return 0;
8492 }
8493
8494 static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
8495                                 loff_t file_offset)
8496 {
8497         struct btrfs_dio_private *dip = NULL;
8498         struct bio *io_bio = NULL;
8499         struct btrfs_io_bio *btrfs_bio;
8500         int skip_sum;
8501         bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
8502         int ret = 0;
8503
8504         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8505
8506         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
8507         if (!io_bio) {
8508                 ret = -ENOMEM;
8509                 goto free_ordered;
8510         }
8511
8512         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8513         if (!dip) {
8514                 ret = -ENOMEM;
8515                 goto free_ordered;
8516         }
8517
8518         dip->private = dio_bio->bi_private;
8519         dip->inode = inode;
8520         dip->logical_offset = file_offset;
8521         dip->bytes = dio_bio->bi_iter.bi_size;
8522         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8523         io_bio->bi_private = dip;
8524         dip->orig_bio = io_bio;
8525         dip->dio_bio = dio_bio;
8526         atomic_set(&dip->pending_bios, 0);
8527         btrfs_bio = btrfs_io_bio(io_bio);
8528         btrfs_bio->logical = file_offset;
8529
8530         if (write) {
8531                 io_bio->bi_end_io = btrfs_endio_direct_write;
8532         } else {
8533                 io_bio->bi_end_io = btrfs_endio_direct_read;
8534                 dip->subio_endio = btrfs_subio_endio_read;
8535         }
8536
8537         /*
8538          * Reset the range for unsubmitted ordered extents (to a 0 length range)
8539          * even if we fail to submit a bio, because in such case we do the
8540          * corresponding error handling below and it must not be done a second
8541          * time by btrfs_direct_IO().
8542          */
8543         if (write) {
8544                 struct btrfs_dio_data *dio_data = current->journal_info;
8545
8546                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
8547                         dip->bytes;
8548                 dio_data->unsubmitted_oe_range_start =
8549                         dio_data->unsubmitted_oe_range_end;
8550         }
8551
8552         ret = btrfs_submit_direct_hook(dip, skip_sum);
8553         if (!ret)
8554                 return;
8555
8556         if (btrfs_bio->end_io)
8557                 btrfs_bio->end_io(btrfs_bio, ret);
8558
8559 free_ordered:
8560         /*
8561          * If we arrived here it means either we failed to submit the dip
8562          * or we either failed to clone the dio_bio or failed to allocate the
8563          * dip. If we cloned the dio_bio and allocated the dip, we can just
8564          * call bio_endio against our io_bio so that we get proper resource
8565          * cleanup if we fail to submit the dip, otherwise, we must do the
8566          * same as btrfs_endio_direct_[write|read] because we can't call these
8567          * callbacks - they require an allocated dip and a clone of dio_bio.
8568          */
8569         if (io_bio && dip) {
8570                 io_bio->bi_error = -EIO;
8571                 bio_endio(io_bio);
8572                 /*
8573                  * The end io callbacks free our dip, do the final put on io_bio
8574                  * and all the cleanup and final put for dio_bio (through
8575                  * dio_end_io()).
8576                  */
8577                 dip = NULL;
8578                 io_bio = NULL;
8579         } else {
8580                 if (write)
8581                         btrfs_endio_direct_write_update_ordered(inode,
8582                                                 file_offset,
8583                                                 dio_bio->bi_iter.bi_size,
8584                                                 0);
8585                 else
8586                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8587                               file_offset + dio_bio->bi_iter.bi_size - 1);
8588
8589                 dio_bio->bi_error = -EIO;
8590                 /*
8591                  * Releases and cleans up our dio_bio, no need to bio_put()
8592                  * nor bio_endio()/bio_io_error() against dio_bio.
8593                  */
8594                 dio_end_io(dio_bio, ret);
8595         }
8596         if (io_bio)
8597                 bio_put(io_bio);
8598         kfree(dip);
8599 }
8600
8601 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
8602                                struct kiocb *iocb,
8603                                const struct iov_iter *iter, loff_t offset)
8604 {
8605         int seg;
8606         int i;
8607         unsigned int blocksize_mask = fs_info->sectorsize - 1;
8608         ssize_t retval = -EINVAL;
8609
8610         if (offset & blocksize_mask)
8611                 goto out;
8612
8613         if (iov_iter_alignment(iter) & blocksize_mask)
8614                 goto out;
8615
8616         /* If this is a write we don't need to check anymore */
8617         if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
8618                 return 0;
8619         /*
8620          * Check to make sure we don't have duplicate iov_base's in this
8621          * iovec, if so return EINVAL, otherwise we'll get csum errors
8622          * when reading back.
8623          */
8624         for (seg = 0; seg < iter->nr_segs; seg++) {
8625                 for (i = seg + 1; i < iter->nr_segs; i++) {
8626                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8627                                 goto out;
8628                 }
8629         }
8630         retval = 0;
8631 out:
8632         return retval;
8633 }
8634
8635 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
8636 {
8637         struct file *file = iocb->ki_filp;
8638         struct inode *inode = file->f_mapping->host;
8639         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8640         struct btrfs_dio_data dio_data = { 0 };
8641         loff_t offset = iocb->ki_pos;
8642         size_t count = 0;
8643         int flags = 0;
8644         bool wakeup = true;
8645         bool relock = false;
8646         ssize_t ret;
8647
8648         if (check_direct_IO(fs_info, iocb, iter, offset))
8649                 return 0;
8650
8651         inode_dio_begin(inode);
8652         smp_mb__after_atomic();
8653
8654         /*
8655          * The generic stuff only does filemap_write_and_wait_range, which
8656          * isn't enough if we've written compressed pages to this area, so
8657          * we need to flush the dirty pages again to make absolutely sure
8658          * that any outstanding dirty pages are on disk.
8659          */
8660         count = iov_iter_count(iter);
8661         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8662                      &BTRFS_I(inode)->runtime_flags))
8663                 filemap_fdatawrite_range(inode->i_mapping, offset,
8664                                          offset + count - 1);
8665
8666         if (iov_iter_rw(iter) == WRITE) {
8667                 /*
8668                  * If the write DIO is beyond the EOF, we need update
8669                  * the isize, but it is protected by i_mutex. So we can
8670                  * not unlock the i_mutex at this case.
8671                  */
8672                 if (offset + count <= inode->i_size) {
8673                         inode_unlock(inode);
8674                         relock = true;
8675                 }
8676                 ret = btrfs_delalloc_reserve_space(inode, offset, count);
8677                 if (ret)
8678                         goto out;
8679                 dio_data.outstanding_extents = div64_u64(count +
8680                                                 BTRFS_MAX_EXTENT_SIZE - 1,
8681                                                 BTRFS_MAX_EXTENT_SIZE);
8682
8683                 /*
8684                  * We need to know how many extents we reserved so that we can
8685                  * do the accounting properly if we go over the number we
8686                  * originally calculated.  Abuse current->journal_info for this.
8687                  */
8688                 dio_data.reserve = round_up(count,
8689                                             fs_info->sectorsize);
8690                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8691                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8692                 current->journal_info = &dio_data;
8693         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8694                                      &BTRFS_I(inode)->runtime_flags)) {
8695                 inode_dio_end(inode);
8696                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8697                 wakeup = false;
8698         }
8699
8700         ret = __blockdev_direct_IO(iocb, inode,
8701                                    fs_info->fs_devices->latest_bdev,
8702                                    iter, btrfs_get_blocks_direct, NULL,
8703                                    btrfs_submit_direct, flags);
8704         if (iov_iter_rw(iter) == WRITE) {
8705                 current->journal_info = NULL;
8706                 if (ret < 0 && ret != -EIOCBQUEUED) {
8707                         if (dio_data.reserve)
8708                                 btrfs_delalloc_release_space(inode, offset,
8709                                                              dio_data.reserve);
8710                         /*
8711                          * On error we might have left some ordered extents
8712                          * without submitting corresponding bios for them, so
8713                          * cleanup them up to avoid other tasks getting them
8714                          * and waiting for them to complete forever.
8715                          */
8716                         if (dio_data.unsubmitted_oe_range_start <
8717                             dio_data.unsubmitted_oe_range_end)
8718                                 btrfs_endio_direct_write_update_ordered(inode,
8719                                         dio_data.unsubmitted_oe_range_start,
8720                                         dio_data.unsubmitted_oe_range_end -
8721                                         dio_data.unsubmitted_oe_range_start,
8722                                         0);
8723                 } else if (ret >= 0 && (size_t)ret < count)
8724                         btrfs_delalloc_release_space(inode, offset,
8725                                                      count - (size_t)ret);
8726         }
8727 out:
8728         if (wakeup)
8729                 inode_dio_end(inode);
8730         if (relock)
8731                 inode_lock(inode);
8732
8733         return ret;
8734 }
8735
8736 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8737
8738 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8739                 __u64 start, __u64 len)
8740 {
8741         int     ret;
8742
8743         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8744         if (ret)
8745                 return ret;
8746
8747         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
8748 }
8749
8750 int btrfs_readpage(struct file *file, struct page *page)
8751 {
8752         struct extent_io_tree *tree;
8753         tree = &BTRFS_I(page->mapping->host)->io_tree;
8754         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8755 }
8756
8757 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8758 {
8759         struct extent_io_tree *tree;
8760         struct inode *inode = page->mapping->host;
8761         int ret;
8762
8763         if (current->flags & PF_MEMALLOC) {
8764                 redirty_page_for_writepage(wbc, page);
8765                 unlock_page(page);
8766                 return 0;
8767         }
8768
8769         /*
8770          * If we are under memory pressure we will call this directly from the
8771          * VM, we need to make sure we have the inode referenced for the ordered
8772          * extent.  If not just return like we didn't do anything.
8773          */
8774         if (!igrab(inode)) {
8775                 redirty_page_for_writepage(wbc, page);
8776                 return AOP_WRITEPAGE_ACTIVATE;
8777         }
8778         tree = &BTRFS_I(page->mapping->host)->io_tree;
8779         ret = extent_write_full_page(tree, page, btrfs_get_extent, wbc);
8780         btrfs_add_delayed_iput(inode);
8781         return ret;
8782 }
8783
8784 static int btrfs_writepages(struct address_space *mapping,
8785                             struct writeback_control *wbc)
8786 {
8787         struct extent_io_tree *tree;
8788
8789         tree = &BTRFS_I(mapping->host)->io_tree;
8790         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
8791 }
8792
8793 static int
8794 btrfs_readpages(struct file *file, struct address_space *mapping,
8795                 struct list_head *pages, unsigned nr_pages)
8796 {
8797         struct extent_io_tree *tree;
8798         tree = &BTRFS_I(mapping->host)->io_tree;
8799         return extent_readpages(tree, mapping, pages, nr_pages,
8800                                 btrfs_get_extent);
8801 }
8802 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8803 {
8804         struct extent_io_tree *tree;
8805         struct extent_map_tree *map;
8806         int ret;
8807
8808         tree = &BTRFS_I(page->mapping->host)->io_tree;
8809         map = &BTRFS_I(page->mapping->host)->extent_tree;
8810         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
8811         if (ret == 1) {
8812                 ClearPagePrivate(page);
8813                 set_page_private(page, 0);
8814                 put_page(page);
8815         }
8816         return ret;
8817 }
8818
8819 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8820 {
8821         if (PageWriteback(page) || PageDirty(page))
8822                 return 0;
8823         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
8824 }
8825
8826 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8827                                  unsigned int length)
8828 {
8829         struct inode *inode = page->mapping->host;
8830         struct extent_io_tree *tree;
8831         struct btrfs_ordered_extent *ordered;
8832         struct extent_state *cached_state = NULL;
8833         u64 page_start = page_offset(page);
8834         u64 page_end = page_start + PAGE_SIZE - 1;
8835         u64 start;
8836         u64 end;
8837         int inode_evicting = inode->i_state & I_FREEING;
8838
8839         /*
8840          * we have the page locked, so new writeback can't start,
8841          * and the dirty bit won't be cleared while we are here.
8842          *
8843          * Wait for IO on this page so that we can safely clear
8844          * the PagePrivate2 bit and do ordered accounting
8845          */
8846         wait_on_page_writeback(page);
8847
8848         tree = &BTRFS_I(inode)->io_tree;
8849         if (offset) {
8850                 btrfs_releasepage(page, GFP_NOFS);
8851                 return;
8852         }
8853
8854         if (!inode_evicting)
8855                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8856 again:
8857         start = page_start;
8858         ordered = btrfs_lookup_ordered_range(inode, start,
8859                                         page_end - start + 1);
8860         if (ordered) {
8861                 end = min(page_end, ordered->file_offset + ordered->len - 1);
8862                 /*
8863                  * IO on this page will never be started, so we need
8864                  * to account for any ordered extents now
8865                  */
8866                 if (!inode_evicting)
8867                         clear_extent_bit(tree, start, end,
8868                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8869                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8870                                          EXTENT_DEFRAG, 1, 0, &cached_state,
8871                                          GFP_NOFS);
8872                 /*
8873                  * whoever cleared the private bit is responsible
8874                  * for the finish_ordered_io
8875                  */
8876                 if (TestClearPagePrivate2(page)) {
8877                         struct btrfs_ordered_inode_tree *tree;
8878                         u64 new_len;
8879
8880                         tree = &BTRFS_I(inode)->ordered_tree;
8881
8882                         spin_lock_irq(&tree->lock);
8883                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8884                         new_len = start - ordered->file_offset;
8885                         if (new_len < ordered->truncated_len)
8886                                 ordered->truncated_len = new_len;
8887                         spin_unlock_irq(&tree->lock);
8888
8889                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8890                                                            start,
8891                                                            end - start + 1, 1))
8892                                 btrfs_finish_ordered_io(ordered);
8893                 }
8894                 btrfs_put_ordered_extent(ordered);
8895                 if (!inode_evicting) {
8896                         cached_state = NULL;
8897                         lock_extent_bits(tree, start, end,
8898                                          &cached_state);
8899                 }
8900
8901                 start = end + 1;
8902                 if (start < page_end)
8903                         goto again;
8904         }
8905
8906         /*
8907          * Qgroup reserved space handler
8908          * Page here will be either
8909          * 1) Already written to disk
8910          *    In this case, its reserved space is released from data rsv map
8911          *    and will be freed by delayed_ref handler finally.
8912          *    So even we call qgroup_free_data(), it won't decrease reserved
8913          *    space.
8914          * 2) Not written to disk
8915          *    This means the reserved space should be freed here. However,
8916          *    if a truncate invalidates the page (by clearing PageDirty)
8917          *    and the page is accounted for while allocating extent
8918          *    in btrfs_check_data_free_space() we let delayed_ref to
8919          *    free the entire extent.
8920          */
8921         if (PageDirty(page))
8922                 btrfs_qgroup_free_data(inode, page_start, PAGE_SIZE);
8923         if (!inode_evicting) {
8924                 clear_extent_bit(tree, page_start, page_end,
8925                                  EXTENT_LOCKED | EXTENT_DIRTY |
8926                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8927                                  EXTENT_DEFRAG, 1, 1,
8928                                  &cached_state, GFP_NOFS);
8929
8930                 __btrfs_releasepage(page, GFP_NOFS);
8931         }
8932
8933         ClearPageChecked(page);
8934         if (PagePrivate(page)) {
8935                 ClearPagePrivate(page);
8936                 set_page_private(page, 0);
8937                 put_page(page);
8938         }
8939 }
8940
8941 /*
8942  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8943  * called from a page fault handler when a page is first dirtied. Hence we must
8944  * be careful to check for EOF conditions here. We set the page up correctly
8945  * for a written page which means we get ENOSPC checking when writing into
8946  * holes and correct delalloc and unwritten extent mapping on filesystems that
8947  * support these features.
8948  *
8949  * We are not allowed to take the i_mutex here so we have to play games to
8950  * protect against truncate races as the page could now be beyond EOF.  Because
8951  * vmtruncate() writes the inode size before removing pages, once we have the
8952  * page lock we can determine safely if the page is beyond EOF. If it is not
8953  * beyond EOF, then the page is guaranteed safe against truncation until we
8954  * unlock the page.
8955  */
8956 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
8957 {
8958         struct page *page = vmf->page;
8959         struct inode *inode = file_inode(vma->vm_file);
8960         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8961         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8962         struct btrfs_ordered_extent *ordered;
8963         struct extent_state *cached_state = NULL;
8964         char *kaddr;
8965         unsigned long zero_start;
8966         loff_t size;
8967         int ret;
8968         int reserved = 0;
8969         u64 reserved_space;
8970         u64 page_start;
8971         u64 page_end;
8972         u64 end;
8973
8974         reserved_space = PAGE_SIZE;
8975
8976         sb_start_pagefault(inode->i_sb);
8977         page_start = page_offset(page);
8978         page_end = page_start + PAGE_SIZE - 1;
8979         end = page_end;
8980
8981         /*
8982          * Reserving delalloc space after obtaining the page lock can lead to
8983          * deadlock. For example, if a dirty page is locked by this function
8984          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8985          * dirty page write out, then the btrfs_writepage() function could
8986          * end up waiting indefinitely to get a lock on the page currently
8987          * being processed by btrfs_page_mkwrite() function.
8988          */
8989         ret = btrfs_delalloc_reserve_space(inode, page_start,
8990                                            reserved_space);
8991         if (!ret) {
8992                 ret = file_update_time(vma->vm_file);
8993                 reserved = 1;
8994         }
8995         if (ret) {
8996                 if (ret == -ENOMEM)
8997                         ret = VM_FAULT_OOM;
8998                 else /* -ENOSPC, -EIO, etc */
8999                         ret = VM_FAULT_SIGBUS;
9000                 if (reserved)
9001                         goto out;
9002                 goto out_noreserve;
9003         }
9004
9005         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
9006 again:
9007         lock_page(page);
9008         size = i_size_read(inode);
9009
9010         if ((page->mapping != inode->i_mapping) ||
9011             (page_start >= size)) {
9012                 /* page got truncated out from underneath us */
9013                 goto out_unlock;
9014         }
9015         wait_on_page_writeback(page);
9016
9017         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
9018         set_page_extent_mapped(page);
9019
9020         /*
9021          * we can't set the delalloc bits if there are pending ordered
9022          * extents.  Drop our locks and wait for them to finish
9023          */
9024         ordered = btrfs_lookup_ordered_range(inode, page_start, page_end);
9025         if (ordered) {
9026                 unlock_extent_cached(io_tree, page_start, page_end,
9027                                      &cached_state, GFP_NOFS);
9028                 unlock_page(page);
9029                 btrfs_start_ordered_extent(inode, ordered, 1);
9030                 btrfs_put_ordered_extent(ordered);
9031                 goto again;
9032         }
9033
9034         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
9035                 reserved_space = round_up(size - page_start,
9036                                           fs_info->sectorsize);
9037                 if (reserved_space < PAGE_SIZE) {
9038                         end = page_start + reserved_space - 1;
9039                         spin_lock(&BTRFS_I(inode)->lock);
9040                         BTRFS_I(inode)->outstanding_extents++;
9041                         spin_unlock(&BTRFS_I(inode)->lock);
9042                         btrfs_delalloc_release_space(inode, page_start,
9043                                                 PAGE_SIZE - reserved_space);
9044                 }
9045         }
9046
9047         /*
9048          * XXX - page_mkwrite gets called every time the page is dirtied, even
9049          * if it was already dirty, so for space accounting reasons we need to
9050          * clear any delalloc bits for the range we are fixing to save.  There
9051          * is probably a better way to do this, but for now keep consistent with
9052          * prepare_pages in the normal write path.
9053          */
9054         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
9055                           EXTENT_DIRTY | EXTENT_DELALLOC |
9056                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
9057                           0, 0, &cached_state, GFP_NOFS);
9058
9059         ret = btrfs_set_extent_delalloc(inode, page_start, end,
9060                                         &cached_state, 0);
9061         if (ret) {
9062                 unlock_extent_cached(io_tree, page_start, page_end,
9063                                      &cached_state, GFP_NOFS);
9064                 ret = VM_FAULT_SIGBUS;
9065                 goto out_unlock;
9066         }
9067         ret = 0;
9068
9069         /* page is wholly or partially inside EOF */
9070         if (page_start + PAGE_SIZE > size)
9071                 zero_start = size & ~PAGE_MASK;
9072         else
9073                 zero_start = PAGE_SIZE;
9074
9075         if (zero_start != PAGE_SIZE) {
9076                 kaddr = kmap(page);
9077                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
9078                 flush_dcache_page(page);
9079                 kunmap(page);
9080         }
9081         ClearPageChecked(page);
9082         set_page_dirty(page);
9083         SetPageUptodate(page);
9084
9085         BTRFS_I(inode)->last_trans = fs_info->generation;
9086         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
9087         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
9088
9089         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
9090
9091 out_unlock:
9092         if (!ret) {
9093                 sb_end_pagefault(inode->i_sb);
9094                 return VM_FAULT_LOCKED;
9095         }
9096         unlock_page(page);
9097 out:
9098         btrfs_delalloc_release_space(inode, page_start, reserved_space);
9099 out_noreserve:
9100         sb_end_pagefault(inode->i_sb);
9101         return ret;
9102 }
9103
9104 static int btrfs_truncate(struct inode *inode)
9105 {
9106         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9107         struct btrfs_root *root = BTRFS_I(inode)->root;
9108         struct btrfs_block_rsv *rsv;
9109         int ret = 0;
9110         int err = 0;
9111         struct btrfs_trans_handle *trans;
9112         u64 mask = fs_info->sectorsize - 1;
9113         u64 min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
9114
9115         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
9116                                        (u64)-1);
9117         if (ret)
9118                 return ret;
9119
9120         /*
9121          * Yes ladies and gentlemen, this is indeed ugly.  The fact is we have
9122          * 3 things going on here
9123          *
9124          * 1) We need to reserve space for our orphan item and the space to
9125          * delete our orphan item.  Lord knows we don't want to have a dangling
9126          * orphan item because we didn't reserve space to remove it.
9127          *
9128          * 2) We need to reserve space to update our inode.
9129          *
9130          * 3) We need to have something to cache all the space that is going to
9131          * be free'd up by the truncate operation, but also have some slack
9132          * space reserved in case it uses space during the truncate (thank you
9133          * very much snapshotting).
9134          *
9135          * And we need these to all be separate.  The fact is we can use a lot of
9136          * space doing the truncate, and we have no earthly idea how much space
9137          * we will use, so we need the truncate reservation to be separate so it
9138          * doesn't end up using space reserved for updating the inode or
9139          * removing the orphan item.  We also need to be able to stop the
9140          * transaction and start a new one, which means we need to be able to
9141          * update the inode several times, and we have no idea of knowing how
9142          * many times that will be, so we can't just reserve 1 item for the
9143          * entirety of the operation, so that has to be done separately as well.
9144          * Then there is the orphan item, which does indeed need to be held on
9145          * to for the whole operation, and we need nobody to touch this reserved
9146          * space except the orphan code.
9147          *
9148          * So that leaves us with
9149          *
9150          * 1) root->orphan_block_rsv - for the orphan deletion.
9151          * 2) rsv - for the truncate reservation, which we will steal from the
9152          * transaction reservation.
9153          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
9154          * updating the inode.
9155          */
9156         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
9157         if (!rsv)
9158                 return -ENOMEM;
9159         rsv->size = min_size;
9160         rsv->failfast = 1;
9161
9162         /*
9163          * 1 for the truncate slack space
9164          * 1 for updating the inode.
9165          */
9166         trans = btrfs_start_transaction(root, 2);
9167         if (IS_ERR(trans)) {
9168                 err = PTR_ERR(trans);
9169                 goto out;
9170         }
9171
9172         /* Migrate the slack space for the truncate to our reserve */
9173         ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
9174                                       min_size, 0);
9175         BUG_ON(ret);
9176
9177         /*
9178          * So if we truncate and then write and fsync we normally would just
9179          * write the extents that changed, which is a problem if we need to
9180          * first truncate that entire inode.  So set this flag so we write out
9181          * all of the extents in the inode to the sync log so we're completely
9182          * safe.
9183          */
9184         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
9185         trans->block_rsv = rsv;
9186
9187         while (1) {
9188                 ret = btrfs_truncate_inode_items(trans, root, inode,
9189                                                  inode->i_size,
9190                                                  BTRFS_EXTENT_DATA_KEY);
9191                 if (ret != -ENOSPC && ret != -EAGAIN) {
9192                         err = ret;
9193                         break;
9194                 }
9195
9196                 trans->block_rsv = &fs_info->trans_block_rsv;
9197                 ret = btrfs_update_inode(trans, root, inode);
9198                 if (ret) {
9199                         err = ret;
9200                         break;
9201                 }
9202
9203                 btrfs_end_transaction(trans, root);
9204                 btrfs_btree_balance_dirty(fs_info);
9205
9206                 trans = btrfs_start_transaction(root, 2);
9207                 if (IS_ERR(trans)) {
9208                         ret = err = PTR_ERR(trans);
9209                         trans = NULL;
9210                         break;
9211                 }
9212
9213                 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
9214                                               rsv, min_size, 0);
9215                 BUG_ON(ret);    /* shouldn't happen */
9216                 trans->block_rsv = rsv;
9217         }
9218
9219         if (ret == 0 && inode->i_nlink > 0) {
9220                 trans->block_rsv = root->orphan_block_rsv;
9221                 ret = btrfs_orphan_del(trans, inode);
9222                 if (ret)
9223                         err = ret;
9224         }
9225
9226         if (trans) {
9227                 trans->block_rsv = &fs_info->trans_block_rsv;
9228                 ret = btrfs_update_inode(trans, root, inode);
9229                 if (ret && !err)
9230                         err = ret;
9231
9232                 ret = btrfs_end_transaction(trans, root);
9233                 btrfs_btree_balance_dirty(fs_info);
9234         }
9235 out:
9236         btrfs_free_block_rsv(fs_info, rsv);
9237
9238         if (ret && !err)
9239                 err = ret;
9240
9241         return err;
9242 }
9243
9244 /*
9245  * create a new subvolume directory/inode (helper for the ioctl).
9246  */
9247 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
9248                              struct btrfs_root *new_root,
9249                              struct btrfs_root *parent_root,
9250                              u64 new_dirid)
9251 {
9252         struct inode *inode;
9253         int err;
9254         u64 index = 0;
9255
9256         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
9257                                 new_dirid, new_dirid,
9258                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
9259                                 &index);
9260         if (IS_ERR(inode))
9261                 return PTR_ERR(inode);
9262         inode->i_op = &btrfs_dir_inode_operations;
9263         inode->i_fop = &btrfs_dir_file_operations;
9264
9265         set_nlink(inode, 1);
9266         btrfs_i_size_write(inode, 0);
9267         unlock_new_inode(inode);
9268
9269         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
9270         if (err)
9271                 btrfs_err(new_root->fs_info,
9272                           "error inheriting subvolume %llu properties: %d",
9273                           new_root->root_key.objectid, err);
9274
9275         err = btrfs_update_inode(trans, new_root, inode);
9276
9277         iput(inode);
9278         return err;
9279 }
9280
9281 struct inode *btrfs_alloc_inode(struct super_block *sb)
9282 {
9283         struct btrfs_inode *ei;
9284         struct inode *inode;
9285
9286         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
9287         if (!ei)
9288                 return NULL;
9289
9290         ei->root = NULL;
9291         ei->generation = 0;
9292         ei->last_trans = 0;
9293         ei->last_sub_trans = 0;
9294         ei->logged_trans = 0;
9295         ei->delalloc_bytes = 0;
9296         ei->defrag_bytes = 0;
9297         ei->disk_i_size = 0;
9298         ei->flags = 0;
9299         ei->csum_bytes = 0;
9300         ei->index_cnt = (u64)-1;
9301         ei->dir_index = 0;
9302         ei->last_unlink_trans = 0;
9303         ei->last_log_commit = 0;
9304         ei->delayed_iput_count = 0;
9305
9306         spin_lock_init(&ei->lock);
9307         ei->outstanding_extents = 0;
9308         ei->reserved_extents = 0;
9309
9310         ei->runtime_flags = 0;
9311         ei->force_compress = BTRFS_COMPRESS_NONE;
9312
9313         ei->delayed_node = NULL;
9314
9315         ei->i_otime.tv_sec = 0;
9316         ei->i_otime.tv_nsec = 0;
9317
9318         inode = &ei->vfs_inode;
9319         extent_map_tree_init(&ei->extent_tree);
9320         extent_io_tree_init(&ei->io_tree, &inode->i_data);
9321         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
9322         ei->io_tree.track_uptodate = 1;
9323         ei->io_failure_tree.track_uptodate = 1;
9324         atomic_set(&ei->sync_writers, 0);
9325         mutex_init(&ei->log_mutex);
9326         mutex_init(&ei->delalloc_mutex);
9327         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9328         INIT_LIST_HEAD(&ei->delalloc_inodes);
9329         INIT_LIST_HEAD(&ei->delayed_iput);
9330         RB_CLEAR_NODE(&ei->rb_node);
9331         init_rwsem(&ei->dio_sem);
9332
9333         return inode;
9334 }
9335
9336 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9337 void btrfs_test_destroy_inode(struct inode *inode)
9338 {
9339         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9340         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9341 }
9342 #endif
9343
9344 static void btrfs_i_callback(struct rcu_head *head)
9345 {
9346         struct inode *inode = container_of(head, struct inode, i_rcu);
9347         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9348 }
9349
9350 void btrfs_destroy_inode(struct inode *inode)
9351 {
9352         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9353         struct btrfs_ordered_extent *ordered;
9354         struct btrfs_root *root = BTRFS_I(inode)->root;
9355
9356         WARN_ON(!hlist_empty(&inode->i_dentry));
9357         WARN_ON(inode->i_data.nrpages);
9358         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9359         WARN_ON(BTRFS_I(inode)->reserved_extents);
9360         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9361         WARN_ON(BTRFS_I(inode)->csum_bytes);
9362         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9363
9364         /*
9365          * This can happen where we create an inode, but somebody else also
9366          * created the same inode and we need to destroy the one we already
9367          * created.
9368          */
9369         if (!root)
9370                 goto free;
9371
9372         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
9373                      &BTRFS_I(inode)->runtime_flags)) {
9374                 btrfs_info(fs_info, "inode %llu still on the orphan list",
9375                            btrfs_ino(inode));
9376                 atomic_dec(&root->orphan_inodes);
9377         }
9378
9379         while (1) {
9380                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9381                 if (!ordered)
9382                         break;
9383                 else {
9384                         btrfs_err(fs_info,
9385                                   "found ordered extent %llu %llu on inode cleanup",
9386                                   ordered->file_offset, ordered->len);
9387                         btrfs_remove_ordered_extent(inode, ordered);
9388                         btrfs_put_ordered_extent(ordered);
9389                         btrfs_put_ordered_extent(ordered);
9390                 }
9391         }
9392         btrfs_qgroup_check_reserved_leak(inode);
9393         inode_tree_del(inode);
9394         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9395 free:
9396         call_rcu(&inode->i_rcu, btrfs_i_callback);
9397 }
9398
9399 int btrfs_drop_inode(struct inode *inode)
9400 {
9401         struct btrfs_root *root = BTRFS_I(inode)->root;
9402
9403         if (root == NULL)
9404                 return 1;
9405
9406         /* the snap/subvol tree is on deleting */
9407         if (btrfs_root_refs(&root->root_item) == 0)
9408                 return 1;
9409         else
9410                 return generic_drop_inode(inode);
9411 }
9412
9413 static void init_once(void *foo)
9414 {
9415         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9416
9417         inode_init_once(&ei->vfs_inode);
9418 }
9419
9420 void btrfs_destroy_cachep(void)
9421 {
9422         /*
9423          * Make sure all delayed rcu free inodes are flushed before we
9424          * destroy cache.
9425          */
9426         rcu_barrier();
9427         kmem_cache_destroy(btrfs_inode_cachep);
9428         kmem_cache_destroy(btrfs_trans_handle_cachep);
9429         kmem_cache_destroy(btrfs_transaction_cachep);
9430         kmem_cache_destroy(btrfs_path_cachep);
9431         kmem_cache_destroy(btrfs_free_space_cachep);
9432 }
9433
9434 int btrfs_init_cachep(void)
9435 {
9436         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9437                         sizeof(struct btrfs_inode), 0,
9438                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
9439                         init_once);
9440         if (!btrfs_inode_cachep)
9441                 goto fail;
9442
9443         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9444                         sizeof(struct btrfs_trans_handle), 0,
9445                         SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
9446         if (!btrfs_trans_handle_cachep)
9447                 goto fail;
9448
9449         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
9450                         sizeof(struct btrfs_transaction), 0,
9451                         SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
9452         if (!btrfs_transaction_cachep)
9453                 goto fail;
9454
9455         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9456                         sizeof(struct btrfs_path), 0,
9457                         SLAB_MEM_SPREAD, NULL);
9458         if (!btrfs_path_cachep)
9459                 goto fail;
9460
9461         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9462                         sizeof(struct btrfs_free_space), 0,
9463                         SLAB_MEM_SPREAD, NULL);
9464         if (!btrfs_free_space_cachep)
9465                 goto fail;
9466
9467         return 0;
9468 fail:
9469         btrfs_destroy_cachep();
9470         return -ENOMEM;
9471 }
9472
9473 static int btrfs_getattr(struct vfsmount *mnt,
9474                          struct dentry *dentry, struct kstat *stat)
9475 {
9476         u64 delalloc_bytes;
9477         struct inode *inode = d_inode(dentry);
9478         u32 blocksize = inode->i_sb->s_blocksize;
9479
9480         generic_fillattr(inode, stat);
9481         stat->dev = BTRFS_I(inode)->root->anon_dev;
9482
9483         spin_lock(&BTRFS_I(inode)->lock);
9484         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
9485         spin_unlock(&BTRFS_I(inode)->lock);
9486         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9487                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9488         return 0;
9489 }
9490
9491 static int btrfs_rename_exchange(struct inode *old_dir,
9492                               struct dentry *old_dentry,
9493                               struct inode *new_dir,
9494                               struct dentry *new_dentry)
9495 {
9496         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9497         struct btrfs_trans_handle *trans;
9498         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9499         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9500         struct inode *new_inode = new_dentry->d_inode;
9501         struct inode *old_inode = old_dentry->d_inode;
9502         struct timespec ctime = current_time(old_inode);
9503         struct dentry *parent;
9504         u64 old_ino = btrfs_ino(old_inode);
9505         u64 new_ino = btrfs_ino(new_inode);
9506         u64 old_idx = 0;
9507         u64 new_idx = 0;
9508         u64 root_objectid;
9509         int ret;
9510         bool root_log_pinned = false;
9511         bool dest_log_pinned = false;
9512
9513         /* we only allow rename subvolume link between subvolumes */
9514         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9515                 return -EXDEV;
9516
9517         /* close the race window with snapshot create/destroy ioctl */
9518         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9519                 down_read(&fs_info->subvol_sem);
9520         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9521                 down_read(&fs_info->subvol_sem);
9522
9523         /*
9524          * We want to reserve the absolute worst case amount of items.  So if
9525          * both inodes are subvols and we need to unlink them then that would
9526          * require 4 item modifications, but if they are both normal inodes it
9527          * would require 5 item modifications, so we'll assume their normal
9528          * inodes.  So 5 * 2 is 10, plus 2 for the new links, so 12 total items
9529          * should cover the worst case number of items we'll modify.
9530          */
9531         trans = btrfs_start_transaction(root, 12);
9532         if (IS_ERR(trans)) {
9533                 ret = PTR_ERR(trans);
9534                 goto out_notrans;
9535         }
9536
9537         /*
9538          * We need to find a free sequence number both in the source and
9539          * in the destination directory for the exchange.
9540          */
9541         ret = btrfs_set_inode_index(new_dir, &old_idx);
9542         if (ret)
9543                 goto out_fail;
9544         ret = btrfs_set_inode_index(old_dir, &new_idx);
9545         if (ret)
9546                 goto out_fail;
9547
9548         BTRFS_I(old_inode)->dir_index = 0ULL;
9549         BTRFS_I(new_inode)->dir_index = 0ULL;
9550
9551         /* Reference for the source. */
9552         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9553                 /* force full log commit if subvolume involved. */
9554                 btrfs_set_log_full_commit(fs_info, trans);
9555         } else {
9556                 btrfs_pin_log_trans(root);
9557                 root_log_pinned = true;
9558                 ret = btrfs_insert_inode_ref(trans, dest,
9559                                              new_dentry->d_name.name,
9560                                              new_dentry->d_name.len,
9561                                              old_ino,
9562                                              btrfs_ino(new_dir), old_idx);
9563                 if (ret)
9564                         goto out_fail;
9565         }
9566
9567         /* And now for the dest. */
9568         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9569                 /* force full log commit if subvolume involved. */
9570                 btrfs_set_log_full_commit(fs_info, trans);
9571         } else {
9572                 btrfs_pin_log_trans(dest);
9573                 dest_log_pinned = true;
9574                 ret = btrfs_insert_inode_ref(trans, root,
9575                                              old_dentry->d_name.name,
9576                                              old_dentry->d_name.len,
9577                                              new_ino,
9578                                              btrfs_ino(old_dir), new_idx);
9579                 if (ret)
9580                         goto out_fail;
9581         }
9582
9583         /* Update inode version and ctime/mtime. */
9584         inode_inc_iversion(old_dir);
9585         inode_inc_iversion(new_dir);
9586         inode_inc_iversion(old_inode);
9587         inode_inc_iversion(new_inode);
9588         old_dir->i_ctime = old_dir->i_mtime = ctime;
9589         new_dir->i_ctime = new_dir->i_mtime = ctime;
9590         old_inode->i_ctime = ctime;
9591         new_inode->i_ctime = ctime;
9592
9593         if (old_dentry->d_parent != new_dentry->d_parent) {
9594                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
9595                 btrfs_record_unlink_dir(trans, new_dir, new_inode, 1);
9596         }
9597
9598         /* src is a subvolume */
9599         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9600                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9601                 ret = btrfs_unlink_subvol(trans, root, old_dir,
9602                                           root_objectid,
9603                                           old_dentry->d_name.name,
9604                                           old_dentry->d_name.len);
9605         } else { /* src is an inode */
9606                 ret = __btrfs_unlink_inode(trans, root, old_dir,
9607                                            old_dentry->d_inode,
9608                                            old_dentry->d_name.name,
9609                                            old_dentry->d_name.len);
9610                 if (!ret)
9611                         ret = btrfs_update_inode(trans, root, old_inode);
9612         }
9613         if (ret) {
9614                 btrfs_abort_transaction(trans, ret);
9615                 goto out_fail;
9616         }
9617
9618         /* dest is a subvolume */
9619         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9620                 root_objectid = BTRFS_I(new_inode)->root->root_key.objectid;
9621                 ret = btrfs_unlink_subvol(trans, dest, new_dir,
9622                                           root_objectid,
9623                                           new_dentry->d_name.name,
9624                                           new_dentry->d_name.len);
9625         } else { /* dest is an inode */
9626                 ret = __btrfs_unlink_inode(trans, dest, new_dir,
9627                                            new_dentry->d_inode,
9628                                            new_dentry->d_name.name,
9629                                            new_dentry->d_name.len);
9630                 if (!ret)
9631                         ret = btrfs_update_inode(trans, dest, new_inode);
9632         }
9633         if (ret) {
9634                 btrfs_abort_transaction(trans, ret);
9635                 goto out_fail;
9636         }
9637
9638         ret = btrfs_add_link(trans, new_dir, old_inode,
9639                              new_dentry->d_name.name,
9640                              new_dentry->d_name.len, 0, old_idx);
9641         if (ret) {
9642                 btrfs_abort_transaction(trans, ret);
9643                 goto out_fail;
9644         }
9645
9646         ret = btrfs_add_link(trans, old_dir, new_inode,
9647                              old_dentry->d_name.name,
9648                              old_dentry->d_name.len, 0, new_idx);
9649         if (ret) {
9650                 btrfs_abort_transaction(trans, ret);
9651                 goto out_fail;
9652         }
9653
9654         if (old_inode->i_nlink == 1)
9655                 BTRFS_I(old_inode)->dir_index = old_idx;
9656         if (new_inode->i_nlink == 1)
9657                 BTRFS_I(new_inode)->dir_index = new_idx;
9658
9659         if (root_log_pinned) {
9660                 parent = new_dentry->d_parent;
9661                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
9662                 btrfs_end_log_trans(root);
9663                 root_log_pinned = false;
9664         }
9665         if (dest_log_pinned) {
9666                 parent = old_dentry->d_parent;
9667                 btrfs_log_new_name(trans, new_inode, new_dir, parent);
9668                 btrfs_end_log_trans(dest);
9669                 dest_log_pinned = false;
9670         }
9671 out_fail:
9672         /*
9673          * If we have pinned a log and an error happened, we unpin tasks
9674          * trying to sync the log and force them to fallback to a transaction
9675          * commit if the log currently contains any of the inodes involved in
9676          * this rename operation (to ensure we do not persist a log with an
9677          * inconsistent state for any of these inodes or leading to any
9678          * inconsistencies when replayed). If the transaction was aborted, the
9679          * abortion reason is propagated to userspace when attempting to commit
9680          * the transaction. If the log does not contain any of these inodes, we
9681          * allow the tasks to sync it.
9682          */
9683         if (ret && (root_log_pinned || dest_log_pinned)) {
9684                 if (btrfs_inode_in_log(old_dir, fs_info->generation) ||
9685                     btrfs_inode_in_log(new_dir, fs_info->generation) ||
9686                     btrfs_inode_in_log(old_inode, fs_info->generation) ||
9687                     (new_inode &&
9688                      btrfs_inode_in_log(new_inode, fs_info->generation)))
9689                         btrfs_set_log_full_commit(fs_info, trans);
9690
9691                 if (root_log_pinned) {
9692                         btrfs_end_log_trans(root);
9693                         root_log_pinned = false;
9694                 }
9695                 if (dest_log_pinned) {
9696                         btrfs_end_log_trans(dest);
9697                         dest_log_pinned = false;
9698                 }
9699         }
9700         ret = btrfs_end_transaction(trans, root);
9701 out_notrans:
9702         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9703                 up_read(&fs_info->subvol_sem);
9704         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9705                 up_read(&fs_info->subvol_sem);
9706
9707         return ret;
9708 }
9709
9710 static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
9711                                      struct btrfs_root *root,
9712                                      struct inode *dir,
9713                                      struct dentry *dentry)
9714 {
9715         int ret;
9716         struct inode *inode;
9717         u64 objectid;
9718         u64 index;
9719
9720         ret = btrfs_find_free_ino(root, &objectid);
9721         if (ret)
9722                 return ret;
9723
9724         inode = btrfs_new_inode(trans, root, dir,
9725                                 dentry->d_name.name,
9726                                 dentry->d_name.len,
9727                                 btrfs_ino(dir),
9728                                 objectid,
9729                                 S_IFCHR | WHITEOUT_MODE,
9730                                 &index);
9731
9732         if (IS_ERR(inode)) {
9733                 ret = PTR_ERR(inode);
9734                 return ret;
9735         }
9736
9737         inode->i_op = &btrfs_special_inode_operations;
9738         init_special_inode(inode, inode->i_mode,
9739                 WHITEOUT_DEV);
9740
9741         ret = btrfs_init_inode_security(trans, inode, dir,
9742                                 &dentry->d_name);
9743         if (ret)
9744                 goto out;
9745
9746         ret = btrfs_add_nondir(trans, dir, dentry,
9747                                 inode, 0, index);
9748         if (ret)
9749                 goto out;
9750
9751         ret = btrfs_update_inode(trans, root, inode);
9752 out:
9753         unlock_new_inode(inode);
9754         if (ret)
9755                 inode_dec_link_count(inode);
9756         iput(inode);
9757
9758         return ret;
9759 }
9760
9761 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9762                            struct inode *new_dir, struct dentry *new_dentry,
9763                            unsigned int flags)
9764 {
9765         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9766         struct btrfs_trans_handle *trans;
9767         unsigned int trans_num_items;
9768         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9769         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9770         struct inode *new_inode = d_inode(new_dentry);
9771         struct inode *old_inode = d_inode(old_dentry);
9772         u64 index = 0;
9773         u64 root_objectid;
9774         int ret;
9775         u64 old_ino = btrfs_ino(old_inode);
9776         bool log_pinned = false;
9777
9778         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9779                 return -EPERM;
9780
9781         /* we only allow rename subvolume link between subvolumes */
9782         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9783                 return -EXDEV;
9784
9785         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9786             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
9787                 return -ENOTEMPTY;
9788
9789         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9790             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9791                 return -ENOTEMPTY;
9792
9793
9794         /* check for collisions, even if the  name isn't there */
9795         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9796                              new_dentry->d_name.name,
9797                              new_dentry->d_name.len);
9798
9799         if (ret) {
9800                 if (ret == -EEXIST) {
9801                         /* we shouldn't get
9802                          * eexist without a new_inode */
9803                         if (WARN_ON(!new_inode)) {
9804                                 return ret;
9805                         }
9806                 } else {
9807                         /* maybe -EOVERFLOW */
9808                         return ret;
9809                 }
9810         }
9811         ret = 0;
9812
9813         /*
9814          * we're using rename to replace one file with another.  Start IO on it
9815          * now so  we don't add too much work to the end of the transaction
9816          */
9817         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9818                 filemap_flush(old_inode->i_mapping);
9819
9820         /* close the racy window with snapshot create/destroy ioctl */
9821         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9822                 down_read(&fs_info->subvol_sem);
9823         /*
9824          * We want to reserve the absolute worst case amount of items.  So if
9825          * both inodes are subvols and we need to unlink them then that would
9826          * require 4 item modifications, but if they are both normal inodes it
9827          * would require 5 item modifications, so we'll assume they are normal
9828          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9829          * should cover the worst case number of items we'll modify.
9830          * If our rename has the whiteout flag, we need more 5 units for the
9831          * new inode (1 inode item, 1 inode ref, 2 dir items and 1 xattr item
9832          * when selinux is enabled).
9833          */
9834         trans_num_items = 11;
9835         if (flags & RENAME_WHITEOUT)
9836                 trans_num_items += 5;
9837         trans = btrfs_start_transaction(root, trans_num_items);
9838         if (IS_ERR(trans)) {
9839                 ret = PTR_ERR(trans);
9840                 goto out_notrans;
9841         }
9842
9843         if (dest != root)
9844                 btrfs_record_root_in_trans(trans, dest);
9845
9846         ret = btrfs_set_inode_index(new_dir, &index);
9847         if (ret)
9848                 goto out_fail;
9849
9850         BTRFS_I(old_inode)->dir_index = 0ULL;
9851         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9852                 /* force full log commit if subvolume involved. */
9853                 btrfs_set_log_full_commit(fs_info, trans);
9854         } else {
9855                 btrfs_pin_log_trans(root);
9856                 log_pinned = true;
9857                 ret = btrfs_insert_inode_ref(trans, dest,
9858                                              new_dentry->d_name.name,
9859                                              new_dentry->d_name.len,
9860                                              old_ino,
9861                                              btrfs_ino(new_dir), index);
9862                 if (ret)
9863                         goto out_fail;
9864         }
9865
9866         inode_inc_iversion(old_dir);
9867         inode_inc_iversion(new_dir);
9868         inode_inc_iversion(old_inode);
9869         old_dir->i_ctime = old_dir->i_mtime =
9870         new_dir->i_ctime = new_dir->i_mtime =
9871         old_inode->i_ctime = current_time(old_dir);
9872
9873         if (old_dentry->d_parent != new_dentry->d_parent)
9874                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
9875
9876         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9877                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9878                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
9879                                         old_dentry->d_name.name,
9880                                         old_dentry->d_name.len);
9881         } else {
9882                 ret = __btrfs_unlink_inode(trans, root, old_dir,
9883                                         d_inode(old_dentry),
9884                                         old_dentry->d_name.name,
9885                                         old_dentry->d_name.len);
9886                 if (!ret)
9887                         ret = btrfs_update_inode(trans, root, old_inode);
9888         }
9889         if (ret) {
9890                 btrfs_abort_transaction(trans, ret);
9891                 goto out_fail;
9892         }
9893
9894         if (new_inode) {
9895                 inode_inc_iversion(new_inode);
9896                 new_inode->i_ctime = current_time(new_inode);
9897                 if (unlikely(btrfs_ino(new_inode) ==
9898                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9899                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9900                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
9901                                                 root_objectid,
9902                                                 new_dentry->d_name.name,
9903                                                 new_dentry->d_name.len);
9904                         BUG_ON(new_inode->i_nlink == 0);
9905                 } else {
9906                         ret = btrfs_unlink_inode(trans, dest, new_dir,
9907                                                  d_inode(new_dentry),
9908                                                  new_dentry->d_name.name,
9909                                                  new_dentry->d_name.len);
9910                 }
9911                 if (!ret && new_inode->i_nlink == 0)
9912                         ret = btrfs_orphan_add(trans, d_inode(new_dentry));
9913                 if (ret) {
9914                         btrfs_abort_transaction(trans, ret);
9915                         goto out_fail;
9916                 }
9917         }
9918
9919         ret = btrfs_add_link(trans, new_dir, old_inode,
9920                              new_dentry->d_name.name,
9921                              new_dentry->d_name.len, 0, index);
9922         if (ret) {
9923                 btrfs_abort_transaction(trans, ret);
9924                 goto out_fail;
9925         }
9926
9927         if (old_inode->i_nlink == 1)
9928                 BTRFS_I(old_inode)->dir_index = index;
9929
9930         if (log_pinned) {
9931                 struct dentry *parent = new_dentry->d_parent;
9932
9933                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
9934                 btrfs_end_log_trans(root);
9935                 log_pinned = false;
9936         }
9937
9938         if (flags & RENAME_WHITEOUT) {
9939                 ret = btrfs_whiteout_for_rename(trans, root, old_dir,
9940                                                 old_dentry);
9941
9942                 if (ret) {
9943                         btrfs_abort_transaction(trans, ret);
9944                         goto out_fail;
9945                 }
9946         }
9947 out_fail:
9948         /*
9949          * If we have pinned the log and an error happened, we unpin tasks
9950          * trying to sync the log and force them to fallback to a transaction
9951          * commit if the log currently contains any of the inodes involved in
9952          * this rename operation (to ensure we do not persist a log with an
9953          * inconsistent state for any of these inodes or leading to any
9954          * inconsistencies when replayed). If the transaction was aborted, the
9955          * abortion reason is propagated to userspace when attempting to commit
9956          * the transaction. If the log does not contain any of these inodes, we
9957          * allow the tasks to sync it.
9958          */
9959         if (ret && log_pinned) {
9960                 if (btrfs_inode_in_log(old_dir, fs_info->generation) ||
9961                     btrfs_inode_in_log(new_dir, fs_info->generation) ||
9962                     btrfs_inode_in_log(old_inode, fs_info->generation) ||
9963                     (new_inode &&
9964                      btrfs_inode_in_log(new_inode, fs_info->generation)))
9965                         btrfs_set_log_full_commit(fs_info, trans);
9966
9967                 btrfs_end_log_trans(root);
9968                 log_pinned = false;
9969         }
9970         btrfs_end_transaction(trans, root);
9971 out_notrans:
9972         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9973                 up_read(&fs_info->subvol_sem);
9974
9975         return ret;
9976 }
9977
9978 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9979                          struct inode *new_dir, struct dentry *new_dentry,
9980                          unsigned int flags)
9981 {
9982         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
9983                 return -EINVAL;
9984
9985         if (flags & RENAME_EXCHANGE)
9986                 return btrfs_rename_exchange(old_dir, old_dentry, new_dir,
9987                                           new_dentry);
9988
9989         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
9990 }
9991
9992 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9993 {
9994         struct btrfs_delalloc_work *delalloc_work;
9995         struct inode *inode;
9996
9997         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9998                                      work);
9999         inode = delalloc_work->inode;
10000         filemap_flush(inode->i_mapping);
10001         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
10002                                 &BTRFS_I(inode)->runtime_flags))
10003                 filemap_flush(inode->i_mapping);
10004
10005         if (delalloc_work->delay_iput)
10006                 btrfs_add_delayed_iput(inode);
10007         else
10008                 iput(inode);
10009         complete(&delalloc_work->completion);
10010 }
10011
10012 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
10013                                                     int delay_iput)
10014 {
10015         struct btrfs_delalloc_work *work;
10016
10017         work = kmalloc(sizeof(*work), GFP_NOFS);
10018         if (!work)
10019                 return NULL;
10020
10021         init_completion(&work->completion);
10022         INIT_LIST_HEAD(&work->list);
10023         work->inode = inode;
10024         work->delay_iput = delay_iput;
10025         WARN_ON_ONCE(!inode);
10026         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
10027                         btrfs_run_delalloc_work, NULL, NULL);
10028
10029         return work;
10030 }
10031
10032 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
10033 {
10034         wait_for_completion(&work->completion);
10035         kfree(work);
10036 }
10037
10038 /*
10039  * some fairly slow code that needs optimization. This walks the list
10040  * of all the inodes with pending delalloc and forces them to disk.
10041  */
10042 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
10043                                    int nr)
10044 {
10045         struct btrfs_inode *binode;
10046         struct inode *inode;
10047         struct btrfs_delalloc_work *work, *next;
10048         struct list_head works;
10049         struct list_head splice;
10050         int ret = 0;
10051
10052         INIT_LIST_HEAD(&works);
10053         INIT_LIST_HEAD(&splice);
10054
10055         mutex_lock(&root->delalloc_mutex);
10056         spin_lock(&root->delalloc_lock);
10057         list_splice_init(&root->delalloc_inodes, &splice);
10058         while (!list_empty(&splice)) {
10059                 binode = list_entry(splice.next, struct btrfs_inode,
10060                                     delalloc_inodes);
10061
10062                 list_move_tail(&binode->delalloc_inodes,
10063                                &root->delalloc_inodes);
10064                 inode = igrab(&binode->vfs_inode);
10065                 if (!inode) {
10066                         cond_resched_lock(&root->delalloc_lock);
10067                         continue;
10068                 }
10069                 spin_unlock(&root->delalloc_lock);
10070
10071                 work = btrfs_alloc_delalloc_work(inode, delay_iput);
10072                 if (!work) {
10073                         if (delay_iput)
10074                                 btrfs_add_delayed_iput(inode);
10075                         else
10076                                 iput(inode);
10077                         ret = -ENOMEM;
10078                         goto out;
10079                 }
10080                 list_add_tail(&work->list, &works);
10081                 btrfs_queue_work(root->fs_info->flush_workers,
10082                                  &work->work);
10083                 ret++;
10084                 if (nr != -1 && ret >= nr)
10085                         goto out;
10086                 cond_resched();
10087                 spin_lock(&root->delalloc_lock);
10088         }
10089         spin_unlock(&root->delalloc_lock);
10090
10091 out:
10092         list_for_each_entry_safe(work, next, &works, list) {
10093                 list_del_init(&work->list);
10094                 btrfs_wait_and_free_delalloc_work(work);
10095         }
10096
10097         if (!list_empty_careful(&splice)) {
10098                 spin_lock(&root->delalloc_lock);
10099                 list_splice_tail(&splice, &root->delalloc_inodes);
10100                 spin_unlock(&root->delalloc_lock);
10101         }
10102         mutex_unlock(&root->delalloc_mutex);
10103         return ret;
10104 }
10105
10106 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
10107 {
10108         struct btrfs_fs_info *fs_info = root->fs_info;
10109         int ret;
10110
10111         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10112                 return -EROFS;
10113
10114         ret = __start_delalloc_inodes(root, delay_iput, -1);
10115         if (ret > 0)
10116                 ret = 0;
10117         /*
10118          * the filemap_flush will queue IO into the worker threads, but
10119          * we have to make sure the IO is actually started and that
10120          * ordered extents get created before we return
10121          */
10122         atomic_inc(&fs_info->async_submit_draining);
10123         while (atomic_read(&fs_info->nr_async_submits) ||
10124                atomic_read(&fs_info->async_delalloc_pages)) {
10125                 wait_event(fs_info->async_submit_wait,
10126                            (atomic_read(&fs_info->nr_async_submits) == 0 &&
10127                             atomic_read(&fs_info->async_delalloc_pages) == 0));
10128         }
10129         atomic_dec(&fs_info->async_submit_draining);
10130         return ret;
10131 }
10132
10133 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
10134                                int nr)
10135 {
10136         struct btrfs_root *root;
10137         struct list_head splice;
10138         int ret;
10139
10140         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10141                 return -EROFS;
10142
10143         INIT_LIST_HEAD(&splice);
10144
10145         mutex_lock(&fs_info->delalloc_root_mutex);
10146         spin_lock(&fs_info->delalloc_root_lock);
10147         list_splice_init(&fs_info->delalloc_roots, &splice);
10148         while (!list_empty(&splice) && nr) {
10149                 root = list_first_entry(&splice, struct btrfs_root,
10150                                         delalloc_root);
10151                 root = btrfs_grab_fs_root(root);
10152                 BUG_ON(!root);
10153                 list_move_tail(&root->delalloc_root,
10154                                &fs_info->delalloc_roots);
10155                 spin_unlock(&fs_info->delalloc_root_lock);
10156
10157                 ret = __start_delalloc_inodes(root, delay_iput, nr);
10158                 btrfs_put_fs_root(root);
10159                 if (ret < 0)
10160                         goto out;
10161
10162                 if (nr != -1) {
10163                         nr -= ret;
10164                         WARN_ON(nr < 0);
10165                 }
10166                 spin_lock(&fs_info->delalloc_root_lock);
10167         }
10168         spin_unlock(&fs_info->delalloc_root_lock);
10169
10170         ret = 0;
10171         atomic_inc(&fs_info->async_submit_draining);
10172         while (atomic_read(&fs_info->nr_async_submits) ||
10173               atomic_read(&fs_info->async_delalloc_pages)) {
10174                 wait_event(fs_info->async_submit_wait,
10175                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
10176                     atomic_read(&fs_info->async_delalloc_pages) == 0));
10177         }
10178         atomic_dec(&fs_info->async_submit_draining);
10179 out:
10180         if (!list_empty_careful(&splice)) {
10181                 spin_lock(&fs_info->delalloc_root_lock);
10182                 list_splice_tail(&splice, &fs_info->delalloc_roots);
10183                 spin_unlock(&fs_info->delalloc_root_lock);
10184         }
10185         mutex_unlock(&fs_info->delalloc_root_mutex);
10186         return ret;
10187 }
10188
10189 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
10190                          const char *symname)
10191 {
10192         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10193         struct btrfs_trans_handle *trans;
10194         struct btrfs_root *root = BTRFS_I(dir)->root;
10195         struct btrfs_path *path;
10196         struct btrfs_key key;
10197         struct inode *inode = NULL;
10198         int err;
10199         int drop_inode = 0;
10200         u64 objectid;
10201         u64 index = 0;
10202         int name_len;
10203         int datasize;
10204         unsigned long ptr;
10205         struct btrfs_file_extent_item *ei;
10206         struct extent_buffer *leaf;
10207
10208         name_len = strlen(symname);
10209         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info))
10210                 return -ENAMETOOLONG;
10211
10212         /*
10213          * 2 items for inode item and ref
10214          * 2 items for dir items
10215          * 1 item for updating parent inode item
10216          * 1 item for the inline extent item
10217          * 1 item for xattr if selinux is on
10218          */
10219         trans = btrfs_start_transaction(root, 7);
10220         if (IS_ERR(trans))
10221                 return PTR_ERR(trans);
10222
10223         err = btrfs_find_free_ino(root, &objectid);
10224         if (err)
10225                 goto out_unlock;
10226
10227         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
10228                                 dentry->d_name.len, btrfs_ino(dir), objectid,
10229                                 S_IFLNK|S_IRWXUGO, &index);
10230         if (IS_ERR(inode)) {
10231                 err = PTR_ERR(inode);
10232                 goto out_unlock;
10233         }
10234
10235         /*
10236         * If the active LSM wants to access the inode during
10237         * d_instantiate it needs these. Smack checks to see
10238         * if the filesystem supports xattrs by looking at the
10239         * ops vector.
10240         */
10241         inode->i_fop = &btrfs_file_operations;
10242         inode->i_op = &btrfs_file_inode_operations;
10243         inode->i_mapping->a_ops = &btrfs_aops;
10244         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10245
10246         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
10247         if (err)
10248                 goto out_unlock_inode;
10249
10250         path = btrfs_alloc_path();
10251         if (!path) {
10252                 err = -ENOMEM;
10253                 goto out_unlock_inode;
10254         }
10255         key.objectid = btrfs_ino(inode);
10256         key.offset = 0;
10257         key.type = BTRFS_EXTENT_DATA_KEY;
10258         datasize = btrfs_file_extent_calc_inline_size(name_len);
10259         err = btrfs_insert_empty_item(trans, root, path, &key,
10260                                       datasize);
10261         if (err) {
10262                 btrfs_free_path(path);
10263                 goto out_unlock_inode;
10264         }
10265         leaf = path->nodes[0];
10266         ei = btrfs_item_ptr(leaf, path->slots[0],
10267                             struct btrfs_file_extent_item);
10268         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
10269         btrfs_set_file_extent_type(leaf, ei,
10270                                    BTRFS_FILE_EXTENT_INLINE);
10271         btrfs_set_file_extent_encryption(leaf, ei, 0);
10272         btrfs_set_file_extent_compression(leaf, ei, 0);
10273         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
10274         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
10275
10276         ptr = btrfs_file_extent_inline_start(ei);
10277         write_extent_buffer(leaf, symname, ptr, name_len);
10278         btrfs_mark_buffer_dirty(leaf);
10279         btrfs_free_path(path);
10280
10281         inode->i_op = &btrfs_symlink_inode_operations;
10282         inode_nohighmem(inode);
10283         inode->i_mapping->a_ops = &btrfs_symlink_aops;
10284         inode_set_bytes(inode, name_len);
10285         btrfs_i_size_write(inode, name_len);
10286         err = btrfs_update_inode(trans, root, inode);
10287         /*
10288          * Last step, add directory indexes for our symlink inode. This is the
10289          * last step to avoid extra cleanup of these indexes if an error happens
10290          * elsewhere above.
10291          */
10292         if (!err)
10293                 err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
10294         if (err) {
10295                 drop_inode = 1;
10296                 goto out_unlock_inode;
10297         }
10298
10299         unlock_new_inode(inode);
10300         d_instantiate(dentry, inode);
10301
10302 out_unlock:
10303         btrfs_end_transaction(trans, root);
10304         if (drop_inode) {
10305                 inode_dec_link_count(inode);
10306                 iput(inode);
10307         }
10308         btrfs_btree_balance_dirty(fs_info);
10309         return err;
10310
10311 out_unlock_inode:
10312         drop_inode = 1;
10313         unlock_new_inode(inode);
10314         goto out_unlock;
10315 }
10316
10317 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
10318                                        u64 start, u64 num_bytes, u64 min_size,
10319                                        loff_t actual_len, u64 *alloc_hint,
10320                                        struct btrfs_trans_handle *trans)
10321 {
10322         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
10323         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
10324         struct extent_map *em;
10325         struct btrfs_root *root = BTRFS_I(inode)->root;
10326         struct btrfs_key ins;
10327         u64 cur_offset = start;
10328         u64 i_size;
10329         u64 cur_bytes;
10330         u64 last_alloc = (u64)-1;
10331         int ret = 0;
10332         bool own_trans = true;
10333         u64 end = start + num_bytes - 1;
10334
10335         if (trans)
10336                 own_trans = false;
10337         while (num_bytes > 0) {
10338                 if (own_trans) {
10339                         trans = btrfs_start_transaction(root, 3);
10340                         if (IS_ERR(trans)) {
10341                                 ret = PTR_ERR(trans);
10342                                 break;
10343                         }
10344                 }
10345
10346                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
10347                 cur_bytes = max(cur_bytes, min_size);
10348                 /*
10349                  * If we are severely fragmented we could end up with really
10350                  * small allocations, so if the allocator is returning small
10351                  * chunks lets make its job easier by only searching for those
10352                  * sized chunks.
10353                  */
10354                 cur_bytes = min(cur_bytes, last_alloc);
10355                 ret = btrfs_reserve_extent(root, cur_bytes, cur_bytes,
10356                                 min_size, 0, *alloc_hint, &ins, 1, 0);
10357                 if (ret) {
10358                         if (own_trans)
10359                                 btrfs_end_transaction(trans, root);
10360                         break;
10361                 }
10362                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
10363
10364                 last_alloc = ins.offset;
10365                 ret = insert_reserved_file_extent(trans, inode,
10366                                                   cur_offset, ins.objectid,
10367                                                   ins.offset, ins.offset,
10368                                                   ins.offset, 0, 0, 0,
10369                                                   BTRFS_FILE_EXTENT_PREALLOC);
10370                 if (ret) {
10371                         btrfs_free_reserved_extent(fs_info, ins.objectid,
10372                                                    ins.offset, 0);
10373                         btrfs_abort_transaction(trans, ret);
10374                         if (own_trans)
10375                                 btrfs_end_transaction(trans, root);
10376                         break;
10377                 }
10378
10379                 btrfs_drop_extent_cache(inode, cur_offset,
10380                                         cur_offset + ins.offset -1, 0);
10381
10382                 em = alloc_extent_map();
10383                 if (!em) {
10384                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
10385                                 &BTRFS_I(inode)->runtime_flags);
10386                         goto next;
10387                 }
10388
10389                 em->start = cur_offset;
10390                 em->orig_start = cur_offset;
10391                 em->len = ins.offset;
10392                 em->block_start = ins.objectid;
10393                 em->block_len = ins.offset;
10394                 em->orig_block_len = ins.offset;
10395                 em->ram_bytes = ins.offset;
10396                 em->bdev = fs_info->fs_devices->latest_bdev;
10397                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
10398                 em->generation = trans->transid;
10399
10400                 while (1) {
10401                         write_lock(&em_tree->lock);
10402                         ret = add_extent_mapping(em_tree, em, 1);
10403                         write_unlock(&em_tree->lock);
10404                         if (ret != -EEXIST)
10405                                 break;
10406                         btrfs_drop_extent_cache(inode, cur_offset,
10407                                                 cur_offset + ins.offset - 1,
10408                                                 0);
10409                 }
10410                 free_extent_map(em);
10411 next:
10412                 num_bytes -= ins.offset;
10413                 cur_offset += ins.offset;
10414                 *alloc_hint = ins.objectid + ins.offset;
10415
10416                 inode_inc_iversion(inode);
10417                 inode->i_ctime = current_time(inode);
10418                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
10419                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
10420                     (actual_len > inode->i_size) &&
10421                     (cur_offset > inode->i_size)) {
10422                         if (cur_offset > actual_len)
10423                                 i_size = actual_len;
10424                         else
10425                                 i_size = cur_offset;
10426                         i_size_write(inode, i_size);
10427                         btrfs_ordered_update_i_size(inode, i_size, NULL);
10428                 }
10429
10430                 ret = btrfs_update_inode(trans, root, inode);
10431
10432                 if (ret) {
10433                         btrfs_abort_transaction(trans, ret);
10434                         if (own_trans)
10435                                 btrfs_end_transaction(trans, root);
10436                         break;
10437                 }
10438
10439                 if (own_trans)
10440                         btrfs_end_transaction(trans, root);
10441         }
10442         if (cur_offset < end)
10443                 btrfs_free_reserved_data_space(inode, cur_offset,
10444                         end - cur_offset + 1);
10445         return ret;
10446 }
10447
10448 int btrfs_prealloc_file_range(struct inode *inode, int mode,
10449                               u64 start, u64 num_bytes, u64 min_size,
10450                               loff_t actual_len, u64 *alloc_hint)
10451 {
10452         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10453                                            min_size, actual_len, alloc_hint,
10454                                            NULL);
10455 }
10456
10457 int btrfs_prealloc_file_range_trans(struct inode *inode,
10458                                     struct btrfs_trans_handle *trans, int mode,
10459                                     u64 start, u64 num_bytes, u64 min_size,
10460                                     loff_t actual_len, u64 *alloc_hint)
10461 {
10462         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10463                                            min_size, actual_len, alloc_hint, trans);
10464 }
10465
10466 static int btrfs_set_page_dirty(struct page *page)
10467 {
10468         return __set_page_dirty_nobuffers(page);
10469 }
10470
10471 static int btrfs_permission(struct inode *inode, int mask)
10472 {
10473         struct btrfs_root *root = BTRFS_I(inode)->root;
10474         umode_t mode = inode->i_mode;
10475
10476         if (mask & MAY_WRITE &&
10477             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
10478                 if (btrfs_root_readonly(root))
10479                         return -EROFS;
10480                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
10481                         return -EACCES;
10482         }
10483         return generic_permission(inode, mask);
10484 }
10485
10486 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
10487 {
10488         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10489         struct btrfs_trans_handle *trans;
10490         struct btrfs_root *root = BTRFS_I(dir)->root;
10491         struct inode *inode = NULL;
10492         u64 objectid;
10493         u64 index;
10494         int ret = 0;
10495
10496         /*
10497          * 5 units required for adding orphan entry
10498          */
10499         trans = btrfs_start_transaction(root, 5);
10500         if (IS_ERR(trans))
10501                 return PTR_ERR(trans);
10502
10503         ret = btrfs_find_free_ino(root, &objectid);
10504         if (ret)
10505                 goto out;
10506
10507         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
10508                                 btrfs_ino(dir), objectid, mode, &index);
10509         if (IS_ERR(inode)) {
10510                 ret = PTR_ERR(inode);
10511                 inode = NULL;
10512                 goto out;
10513         }
10514
10515         inode->i_fop = &btrfs_file_operations;
10516         inode->i_op = &btrfs_file_inode_operations;
10517
10518         inode->i_mapping->a_ops = &btrfs_aops;
10519         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10520
10521         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
10522         if (ret)
10523                 goto out_inode;
10524
10525         ret = btrfs_update_inode(trans, root, inode);
10526         if (ret)
10527                 goto out_inode;
10528         ret = btrfs_orphan_add(trans, inode);
10529         if (ret)
10530                 goto out_inode;
10531
10532         /*
10533          * We set number of links to 0 in btrfs_new_inode(), and here we set
10534          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
10535          * through:
10536          *
10537          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
10538          */
10539         set_nlink(inode, 1);
10540         unlock_new_inode(inode);
10541         d_tmpfile(dentry, inode);
10542         mark_inode_dirty(inode);
10543
10544 out:
10545         btrfs_end_transaction(trans, root);
10546         if (ret)
10547                 iput(inode);
10548         btrfs_balance_delayed_items(fs_info);
10549         btrfs_btree_balance_dirty(fs_info);
10550         return ret;
10551
10552 out_inode:
10553         unlock_new_inode(inode);
10554         goto out;
10555
10556 }
10557
10558 static const struct inode_operations btrfs_dir_inode_operations = {
10559         .getattr        = btrfs_getattr,
10560         .lookup         = btrfs_lookup,
10561         .create         = btrfs_create,
10562         .unlink         = btrfs_unlink,
10563         .link           = btrfs_link,
10564         .mkdir          = btrfs_mkdir,
10565         .rmdir          = btrfs_rmdir,
10566         .rename         = btrfs_rename2,
10567         .symlink        = btrfs_symlink,
10568         .setattr        = btrfs_setattr,
10569         .mknod          = btrfs_mknod,
10570         .listxattr      = btrfs_listxattr,
10571         .permission     = btrfs_permission,
10572         .get_acl        = btrfs_get_acl,
10573         .set_acl        = btrfs_set_acl,
10574         .update_time    = btrfs_update_time,
10575         .tmpfile        = btrfs_tmpfile,
10576 };
10577 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10578         .lookup         = btrfs_lookup,
10579         .permission     = btrfs_permission,
10580         .get_acl        = btrfs_get_acl,
10581         .set_acl        = btrfs_set_acl,
10582         .update_time    = btrfs_update_time,
10583 };
10584
10585 static const struct file_operations btrfs_dir_file_operations = {
10586         .llseek         = generic_file_llseek,
10587         .read           = generic_read_dir,
10588         .iterate_shared = btrfs_real_readdir,
10589         .unlocked_ioctl = btrfs_ioctl,
10590 #ifdef CONFIG_COMPAT
10591         .compat_ioctl   = btrfs_compat_ioctl,
10592 #endif
10593         .release        = btrfs_release_file,
10594         .fsync          = btrfs_sync_file,
10595 };
10596
10597 static const struct extent_io_ops btrfs_extent_io_ops = {
10598         .fill_delalloc = run_delalloc_range,
10599         .submit_bio_hook = btrfs_submit_bio_hook,
10600         .merge_bio_hook = btrfs_merge_bio_hook,
10601         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10602         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10603         .writepage_start_hook = btrfs_writepage_start_hook,
10604         .set_bit_hook = btrfs_set_bit_hook,
10605         .clear_bit_hook = btrfs_clear_bit_hook,
10606         .merge_extent_hook = btrfs_merge_extent_hook,
10607         .split_extent_hook = btrfs_split_extent_hook,
10608 };
10609
10610 /*
10611  * btrfs doesn't support the bmap operation because swapfiles
10612  * use bmap to make a mapping of extents in the file.  They assume
10613  * these extents won't change over the life of the file and they
10614  * use the bmap result to do IO directly to the drive.
10615  *
10616  * the btrfs bmap call would return logical addresses that aren't
10617  * suitable for IO and they also will change frequently as COW
10618  * operations happen.  So, swapfile + btrfs == corruption.
10619  *
10620  * For now we're avoiding this by dropping bmap.
10621  */
10622 static const struct address_space_operations btrfs_aops = {
10623         .readpage       = btrfs_readpage,
10624         .writepage      = btrfs_writepage,
10625         .writepages     = btrfs_writepages,
10626         .readpages      = btrfs_readpages,
10627         .direct_IO      = btrfs_direct_IO,
10628         .invalidatepage = btrfs_invalidatepage,
10629         .releasepage    = btrfs_releasepage,
10630         .set_page_dirty = btrfs_set_page_dirty,
10631         .error_remove_page = generic_error_remove_page,
10632 };
10633
10634 static const struct address_space_operations btrfs_symlink_aops = {
10635         .readpage       = btrfs_readpage,
10636         .writepage      = btrfs_writepage,
10637         .invalidatepage = btrfs_invalidatepage,
10638         .releasepage    = btrfs_releasepage,
10639 };
10640
10641 static const struct inode_operations btrfs_file_inode_operations = {
10642         .getattr        = btrfs_getattr,
10643         .setattr        = btrfs_setattr,
10644         .listxattr      = btrfs_listxattr,
10645         .permission     = btrfs_permission,
10646         .fiemap         = btrfs_fiemap,
10647         .get_acl        = btrfs_get_acl,
10648         .set_acl        = btrfs_set_acl,
10649         .update_time    = btrfs_update_time,
10650 };
10651 static const struct inode_operations btrfs_special_inode_operations = {
10652         .getattr        = btrfs_getattr,
10653         .setattr        = btrfs_setattr,
10654         .permission     = btrfs_permission,
10655         .listxattr      = btrfs_listxattr,
10656         .get_acl        = btrfs_get_acl,
10657         .set_acl        = btrfs_set_acl,
10658         .update_time    = btrfs_update_time,
10659 };
10660 static const struct inode_operations btrfs_symlink_inode_operations = {
10661         .readlink       = generic_readlink,
10662         .get_link       = page_get_link,
10663         .getattr        = btrfs_getattr,
10664         .setattr        = btrfs_setattr,
10665         .permission     = btrfs_permission,
10666         .listxattr      = btrfs_listxattr,
10667         .update_time    = btrfs_update_time,
10668 };
10669
10670 const struct dentry_operations btrfs_dentry_operations = {
10671         .d_delete       = btrfs_dentry_delete,
10672         .d_release      = btrfs_dentry_release,
10673 };