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/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/aio.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/xattr.h>
  38 #include <linux/posix_acl.h>
  39 #include <linux/falloc.h>
  40 #include <linux/slab.h>
  41 #include <linux/ratelimit.h>
  42 #include <linux/mount.h>
  43 #include <linux/btrfs.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/posix_acl_xattr.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62
  63 struct btrfs_iget_args {
  64         struct btrfs_key *location;
  65         struct btrfs_root *root;
  66 };
  67
  68 static const struct inode_operations btrfs_dir_inode_operations;
  69 static const struct inode_operations btrfs_symlink_inode_operations;
  70 static const struct inode_operations btrfs_dir_ro_inode_operations;
  71 static const struct inode_operations btrfs_special_inode_operations;
  72 static const struct inode_operations btrfs_file_inode_operations;
  73 static const struct address_space_operations btrfs_aops;
  74 static const struct address_space_operations btrfs_symlink_aops;
  75 static const struct file_operations btrfs_dir_file_operations;
  76 static struct extent_io_ops btrfs_extent_io_ops;
  77
  78 static struct kmem_cache *btrfs_inode_cachep;
  79 static struct kmem_cache *btrfs_delalloc_work_cachep;
  80 struct kmem_cache *btrfs_trans_handle_cachep;
  81 struct kmem_cache *btrfs_transaction_cachep;
  82 struct kmem_cache *btrfs_path_cachep;
  83 struct kmem_cache *btrfs_free_space_cachep;
  84
  85 #define S_SHIFT 12
  86 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  87         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  88         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  89         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  90         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  91         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  92         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  93         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  94 };
  95
  96 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  97 static int btrfs_truncate(struct inode *inode);
  98 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  99 static noinline int cow_file_range(struct inode *inode,
 100                                    struct page *locked_page,
 101                                    u64 start, u64 end, int *page_started,
 102                                    unsigned long *nr_written, int unlock);
 103 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 104                                            u64 len, u64 orig_start,
 105                                            u64 block_start, u64 block_len,
 106                                            u64 orig_block_len, u64 ram_bytes,
 107                                            int type);
 108
 109 static int btrfs_dirty_inode(struct inode *inode);
 110
 111 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 112                                      struct inode *inode,  struct inode *dir,
 113                                      const struct qstr *qstr)
 114 {
 115         int err;
 116
 117         err = btrfs_init_acl(trans, inode, dir);
 118         if (!err)
 119                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 120         return err;
 121 }
 122
 123 /*
 124  * this does all the hard work for inserting an inline extent into
 125  * the btree.  The caller should have done a btrfs_drop_extents so that
 126  * no overlapping inline items exist in the btree
 127  */
 128 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
 129                                 struct btrfs_path *path, int extent_inserted,
 130                                 struct btrfs_root *root, struct inode *inode,
 131                                 u64 start, size_t size, size_t compressed_size,
 132                                 int compress_type,
 133                                 struct page **compressed_pages)
 134 {
 135         struct extent_buffer *leaf;
 136         struct page *page = NULL;
 137         char *kaddr;
 138         unsigned long ptr;
 139         struct btrfs_file_extent_item *ei;
 140         int err = 0;
 141         int ret;
 142         size_t cur_size = size;
 143         unsigned long offset;
 144
 145         if (compressed_size && compressed_pages)
 146                 cur_size = compressed_size;
 147
 148         inode_add_bytes(inode, size);
 149
 150         if (!extent_inserted) {
 151                 struct btrfs_key key;
 152                 size_t datasize;
 153
 154                 key.objectid = btrfs_ino(inode);
 155                 key.offset = start;
 156                 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 157
 158                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 159                 path->leave_spinning = 1;
 160                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 161                                               datasize);
 162                 if (ret) {
 163                         err = ret;
 164                         goto fail;
 165                 }
 166         }
 167         leaf = path->nodes[0];
 168         ei = btrfs_item_ptr(leaf, path->slots[0],
 169                             struct btrfs_file_extent_item);
 170         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 171         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 172         btrfs_set_file_extent_encryption(leaf, ei, 0);
 173         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 174         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 175         ptr = btrfs_file_extent_inline_start(ei);
 176
 177         if (compress_type != BTRFS_COMPRESS_NONE) {
 178                 struct page *cpage;
 179                 int i = 0;
 180                 while (compressed_size > 0) {
 181                         cpage = compressed_pages[i];
 182                         cur_size = min_t(unsigned long, compressed_size,
 183                                        PAGE_CACHE_SIZE);
 184
 185                         kaddr = kmap_atomic(cpage);
 186                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 187                         kunmap_atomic(kaddr);
 188
 189                         i++;
 190                         ptr += cur_size;
 191                         compressed_size -= cur_size;
 192                 }
 193                 btrfs_set_file_extent_compression(leaf, ei,
 194                                                   compress_type);
 195         } else {
 196                 page = find_get_page(inode->i_mapping,
 197                                      start >> PAGE_CACHE_SHIFT);
 198                 btrfs_set_file_extent_compression(leaf, ei, 0);
 199                 kaddr = kmap_atomic(page);
 200                 offset = start & (PAGE_CACHE_SIZE - 1);
 201                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 202                 kunmap_atomic(kaddr);
 203                 page_cache_release(page);
 204         }
 205         btrfs_mark_buffer_dirty(leaf);
 206         btrfs_release_path(path);
 207
 208         /*
 209          * we're an inline extent, so nobody can
 210          * extend the file past i_size without locking
 211          * a page we already have locked.
 212          *
 213          * We must do any isize and inode updates
 214          * before we unlock the pages.  Otherwise we
 215          * could end up racing with unlink.
 216          */
 217         BTRFS_I(inode)->disk_i_size = inode->i_size;
 218         ret = btrfs_update_inode(trans, root, inode);
 219
 220         return ret;
 221 fail:
 222         return err;
 223 }
 224
 225
 226 /*
 227  * conditionally insert an inline extent into the file.  This
 228  * does the checks required to make sure the data is small enough
 229  * to fit as an inline extent.
 230  */
 231 static noinline int cow_file_range_inline(struct btrfs_root *root,
 232                                           struct inode *inode, u64 start,
 233                                           u64 end, size_t compressed_size,
 234                                           int compress_type,
 235                                           struct page **compressed_pages)
 236 {
 237         struct btrfs_trans_handle *trans;
 238         u64 isize = i_size_read(inode);
 239         u64 actual_end = min(end + 1, isize);
 240         u64 inline_len = actual_end - start;
 241         u64 aligned_end = ALIGN(end, root->sectorsize);
 242         u64 data_len = inline_len;
 243         int ret;
 244         struct btrfs_path *path;
 245         int extent_inserted = 0;
 246         u32 extent_item_size;
 247
 248         if (compressed_size)
 249                 data_len = compressed_size;
 250
 251         if (start > 0 ||
 252             actual_end >= PAGE_CACHE_SIZE ||
 253             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 254             (!compressed_size &&
 255             (actual_end & (root->sectorsize - 1)) == 0) ||
 256             end + 1 < isize ||
 257             data_len > root->fs_info->max_inline) {
 258                 return 1;
 259         }
 260
 261         path = btrfs_alloc_path();
 262         if (!path)
 263                 return -ENOMEM;
 264
 265         trans = btrfs_join_transaction(root);
 266         if (IS_ERR(trans)) {
 267                 btrfs_free_path(path);
 268                 return PTR_ERR(trans);
 269         }
 270         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 271
 272         if (compressed_size && compressed_pages)
 273                 extent_item_size = btrfs_file_extent_calc_inline_size(
 274                    compressed_size);
 275         else
 276                 extent_item_size = btrfs_file_extent_calc_inline_size(
 277                     inline_len);
 278
 279         ret = __btrfs_drop_extents(trans, root, inode, path,
 280                                    start, aligned_end, NULL,
 281                                    1, 1, extent_item_size, &extent_inserted);
 282         if (ret) {
 283                 btrfs_abort_transaction(trans, root, ret);
 284                 goto out;
 285         }
 286
 287         if (isize > actual_end)
 288                 inline_len = min_t(u64, isize, actual_end);
 289         ret = insert_inline_extent(trans, path, extent_inserted,
 290                                    root, inode, start,
 291                                    inline_len, compressed_size,
 292                                    compress_type, compressed_pages);
 293         if (ret && ret != -ENOSPC) {
 294                 btrfs_abort_transaction(trans, root, ret);
 295                 goto out;
 296         } else if (ret == -ENOSPC) {
 297                 ret = 1;
 298                 goto out;
 299         }
 300
 301         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 302         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 303         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 304 out:
 305         btrfs_free_path(path);
 306         btrfs_end_transaction(trans, root);
 307         return ret;
 308 }
 309
 310 struct async_extent {
 311         u64 start;
 312         u64 ram_size;
 313         u64 compressed_size;
 314         struct page **pages;
 315         unsigned long nr_pages;
 316         int compress_type;
 317         struct list_head list;
 318 };
 319
 320 struct async_cow {
 321         struct inode *inode;
 322         struct btrfs_root *root;
 323         struct page *locked_page;
 324         u64 start;
 325         u64 end;
 326         struct list_head extents;
 327         struct btrfs_work work;
 328 };
 329
 330 static noinline int add_async_extent(struct async_cow *cow,
 331                                      u64 start, u64 ram_size,
 332                                      u64 compressed_size,
 333                                      struct page **pages,
 334                                      unsigned long nr_pages,
 335                                      int compress_type)
 336 {
 337         struct async_extent *async_extent;
 338
 339         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 340         BUG_ON(!async_extent); /* -ENOMEM */
 341         async_extent->start = start;
 342         async_extent->ram_size = ram_size;
 343         async_extent->compressed_size = compressed_size;
 344         async_extent->pages = pages;
 345         async_extent->nr_pages = nr_pages;
 346         async_extent->compress_type = compress_type;
 347         list_add_tail(&async_extent->list, &cow->extents);
 348         return 0;
 349 }
 350
 351 /*
 352  * we create compressed extents in two phases.  The first
 353  * phase compresses a range of pages that have already been
 354  * locked (both pages and state bits are locked).
 355  *
 356  * This is done inside an ordered work queue, and the compression
 357  * is spread across many cpus.  The actual IO submission is step
 358  * two, and the ordered work queue takes care of making sure that
 359  * happens in the same order things were put onto the queue by
 360  * writepages and friends.
 361  *
 362  * If this code finds it can't get good compression, it puts an
 363  * entry onto the work queue to write the uncompressed bytes.  This
 364  * makes sure that both compressed inodes and uncompressed inodes
 365  * are written in the same order that the flusher thread sent them
 366  * down.
 367  */
 368 static noinline int compress_file_range(struct inode *inode,
 369                                         struct page *locked_page,
 370                                         u64 start, u64 end,
 371                                         struct async_cow *async_cow,
 372                                         int *num_added)
 373 {
 374         struct btrfs_root *root = BTRFS_I(inode)->root;
 375         u64 num_bytes;
 376         u64 blocksize = root->sectorsize;
 377         u64 actual_end;
 378         u64 isize = i_size_read(inode);
 379         int ret = 0;
 380         struct page **pages = NULL;
 381         unsigned long nr_pages;
 382         unsigned long nr_pages_ret = 0;
 383         unsigned long total_compressed = 0;
 384         unsigned long total_in = 0;
 385         unsigned long max_compressed = 128 * 1024;
 386         unsigned long max_uncompressed = 128 * 1024;
 387         int i;
 388         int will_compress;
 389         int compress_type = root->fs_info->compress_type;
 390         int redirty = 0;
 391
 392         /* if this is a small write inside eof, kick off a defrag */
 393         if ((end - start + 1) < 16 * 1024 &&
 394             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 395                 btrfs_add_inode_defrag(NULL, inode);
 396
 397         actual_end = min_t(u64, isize, end + 1);
 398 again:
 399         will_compress = 0;
 400         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 401         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 402
 403         /*
 404          * we don't want to send crud past the end of i_size through
 405          * compression, that's just a waste of CPU time.  So, if the
 406          * end of the file is before the start of our current
 407          * requested range of bytes, we bail out to the uncompressed
 408          * cleanup code that can deal with all of this.
 409          *
 410          * It isn't really the fastest way to fix things, but this is a
 411          * very uncommon corner.
 412          */
 413         if (actual_end <= start)
 414                 goto cleanup_and_bail_uncompressed;
 415
 416         total_compressed = actual_end - start;
 417
 418         /* we want to make sure that amount of ram required to uncompress
 419          * an extent is reasonable, so we limit the total size in ram
 420          * of a compressed extent to 128k.  This is a crucial number
 421          * because it also controls how easily we can spread reads across
 422          * cpus for decompression.
 423          *
 424          * We also want to make sure the amount of IO required to do
 425          * a random read is reasonably small, so we limit the size of
 426          * a compressed extent to 128k.
 427          */
 428         total_compressed = min(total_compressed, max_uncompressed);
 429         num_bytes = ALIGN(end - start + 1, blocksize);
 430         num_bytes = max(blocksize,  num_bytes);
 431         total_in = 0;
 432         ret = 0;
 433
 434         /*
 435          * we do compression for mount -o compress and when the
 436          * inode has not been flagged as nocompress.  This flag can
 437          * change at any time if we discover bad compression ratios.
 438          */
 439         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
 440             (btrfs_test_opt(root, COMPRESS) ||
 441              (BTRFS_I(inode)->force_compress) ||
 442              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
 443                 WARN_ON(pages);
 444                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 445                 if (!pages) {
 446                         /* just bail out to the uncompressed code */
 447                         goto cont;
 448                 }
 449
 450                 if (BTRFS_I(inode)->force_compress)
 451                         compress_type = BTRFS_I(inode)->force_compress;
 452
 453                 /*
 454                  * we need to call clear_page_dirty_for_io on each
 455                  * page in the range.  Otherwise applications with the file
 456                  * mmap'd can wander in and change the page contents while
 457                  * we are compressing them.
 458                  *
 459                  * If the compression fails for any reason, we set the pages
 460                  * dirty again later on.
 461                  */
 462                 extent_range_clear_dirty_for_io(inode, start, end);
 463                 redirty = 1;
 464                 ret = btrfs_compress_pages(compress_type,
 465                                            inode->i_mapping, start,
 466                                            total_compressed, pages,
 467                                            nr_pages, &nr_pages_ret,
 468                                            &total_in,
 469                                            &total_compressed,
 470                                            max_compressed);
 471
 472                 if (!ret) {
 473                         unsigned long offset = total_compressed &
 474                                 (PAGE_CACHE_SIZE - 1);
 475                         struct page *page = pages[nr_pages_ret - 1];
 476                         char *kaddr;
 477
 478                         /* zero the tail end of the last page, we might be
 479                          * sending it down to disk
 480                          */
 481                         if (offset) {
 482                                 kaddr = kmap_atomic(page);
 483                                 memset(kaddr + offset, 0,
 484                                        PAGE_CACHE_SIZE - offset);
 485                                 kunmap_atomic(kaddr);
 486                         }
 487                         will_compress = 1;
 488                 }
 489         }
 490 cont:
 491         if (start == 0) {
 492                 /* lets try to make an inline extent */
 493                 if (ret || total_in < (actual_end - start)) {
 494                         /* we didn't compress the entire range, try
 495                          * to make an uncompressed inline extent.
 496                          */
 497                         ret = cow_file_range_inline(root, inode, start, end,
 498                                                     0, 0, NULL);
 499                 } else {
 500                         /* try making a compressed inline extent */
 501                         ret = cow_file_range_inline(root, inode, start, end,
 502                                                     total_compressed,
 503                                                     compress_type, pages);
 504                 }
 505                 if (ret <= 0) {
 506                         unsigned long clear_flags = EXTENT_DELALLOC |
 507                                 EXTENT_DEFRAG;
 508                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 509
 510                         /*
 511                          * inline extent creation worked or returned error,
 512                          * we don't need to create any more async work items.
 513                          * Unlock and free up our temp pages.
 514                          */
 515                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 516                                                      clear_flags, PAGE_UNLOCK |
 517                                                      PAGE_CLEAR_DIRTY |
 518                                                      PAGE_SET_WRITEBACK |
 519                                                      PAGE_END_WRITEBACK);
 520                         goto free_pages_out;
 521                 }
 522         }
 523
 524         if (will_compress) {
 525                 /*
 526                  * we aren't doing an inline extent round the compressed size
 527                  * up to a block size boundary so the allocator does sane
 528                  * things
 529                  */
 530                 total_compressed = ALIGN(total_compressed, blocksize);
 531
 532                 /*
 533                  * one last check to make sure the compression is really a
 534                  * win, compare the page count read with the blocks on disk
 535                  */
 536                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 537                 if (total_compressed >= total_in) {
 538                         will_compress = 0;
 539                 } else {
 540                         num_bytes = total_in;
 541                 }
 542         }
 543         if (!will_compress && pages) {
 544                 /*
 545                  * the compression code ran but failed to make things smaller,
 546                  * free any pages it allocated and our page pointer array
 547                  */
 548                 for (i = 0; i < nr_pages_ret; i++) {
 549                         WARN_ON(pages[i]->mapping);
 550                         page_cache_release(pages[i]);
 551                 }
 552                 kfree(pages);
 553                 pages = NULL;
 554                 total_compressed = 0;
 555                 nr_pages_ret = 0;
 556
 557                 /* flag the file so we don't compress in the future */
 558                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 559                     !(BTRFS_I(inode)->force_compress)) {
 560                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 561                 }
 562         }
 563         if (will_compress) {
 564                 *num_added += 1;
 565
 566                 /* the async work queues will take care of doing actual
 567                  * allocation on disk for these compressed pages,
 568                  * and will submit them to the elevator.
 569                  */
 570                 add_async_extent(async_cow, start, num_bytes,
 571                                  total_compressed, pages, nr_pages_ret,
 572                                  compress_type);
 573
 574                 if (start + num_bytes < end) {
 575                         start += num_bytes;
 576                         pages = NULL;
 577                         cond_resched();
 578                         goto again;
 579                 }
 580         } else {
 581 cleanup_and_bail_uncompressed:
 582                 /*
 583                  * No compression, but we still need to write the pages in
 584                  * the file we've been given so far.  redirty the locked
 585                  * page if it corresponds to our extent and set things up
 586                  * for the async work queue to run cow_file_range to do
 587                  * the normal delalloc dance
 588                  */
 589                 if (page_offset(locked_page) >= start &&
 590                     page_offset(locked_page) <= end) {
 591                         __set_page_dirty_nobuffers(locked_page);
 592                         /* unlocked later on in the async handlers */
 593                 }
 594                 if (redirty)
 595                         extent_range_redirty_for_io(inode, start, end);
 596                 add_async_extent(async_cow, start, end - start + 1,
 597                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 598                 *num_added += 1;
 599         }
 600
 601 out:
 602         return ret;
 603
 604 free_pages_out:
 605         for (i = 0; i < nr_pages_ret; i++) {
 606                 WARN_ON(pages[i]->mapping);
 607                 page_cache_release(pages[i]);
 608         }
 609         kfree(pages);
 610
 611         goto out;
 612 }
 613
 614 /*
 615  * phase two of compressed writeback.  This is the ordered portion
 616  * of the code, which only gets called in the order the work was
 617  * queued.  We walk all the async extents created by compress_file_range
 618  * and send them down to the disk.
 619  */
 620 static noinline int submit_compressed_extents(struct inode *inode,
 621                                               struct async_cow *async_cow)
 622 {
 623         struct async_extent *async_extent;
 624         u64 alloc_hint = 0;
 625         struct btrfs_key ins;
 626         struct extent_map *em;
 627         struct btrfs_root *root = BTRFS_I(inode)->root;
 628         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 629         struct extent_io_tree *io_tree;
 630         int ret = 0;
 631
 632         if (list_empty(&async_cow->extents))
 633                 return 0;
 634
 635 again:
 636         while (!list_empty(&async_cow->extents)) {
 637                 async_extent = list_entry(async_cow->extents.next,
 638                                           struct async_extent, list);
 639                 list_del(&async_extent->list);
 640
 641                 io_tree = &BTRFS_I(inode)->io_tree;
 642
 643 retry:
 644                 /* did the compression code fall back to uncompressed IO? */
 645                 if (!async_extent->pages) {
 646                         int page_started = 0;
 647                         unsigned long nr_written = 0;
 648
 649                         lock_extent(io_tree, async_extent->start,
 650                                          async_extent->start +
 651                                          async_extent->ram_size - 1);
 652
 653                         /* allocate blocks */
 654                         ret = cow_file_range(inode, async_cow->locked_page,
 655                                              async_extent->start,
 656                                              async_extent->start +
 657                                              async_extent->ram_size - 1,
 658                                              &page_started, &nr_written, 0);
 659
 660                         /* JDM XXX */
 661
 662                         /*
 663                          * if page_started, cow_file_range inserted an
 664                          * inline extent and took care of all the unlocking
 665                          * and IO for us.  Otherwise, we need to submit
 666                          * all those pages down to the drive.
 667                          */
 668                         if (!page_started && !ret)
 669                                 extent_write_locked_range(io_tree,
 670                                                   inode, async_extent->start,
 671                                                   async_extent->start +
 672                                                   async_extent->ram_size - 1,
 673                                                   btrfs_get_extent,
 674                                                   WB_SYNC_ALL);
 675                         else if (ret)
 676                                 unlock_page(async_cow->locked_page);
 677                         kfree(async_extent);
 678                         cond_resched();
 679                         continue;
 680                 }
 681
 682                 lock_extent(io_tree, async_extent->start,
 683                             async_extent->start + async_extent->ram_size - 1);
 684
 685                 ret = btrfs_reserve_extent(root,
 686                                            async_extent->compressed_size,
 687                                            async_extent->compressed_size,
 688                                            0, alloc_hint, &ins, 1);
 689                 if (ret) {
 690                         int i;
 691
 692                         for (i = 0; i < async_extent->nr_pages; i++) {
 693                                 WARN_ON(async_extent->pages[i]->mapping);
 694                                 page_cache_release(async_extent->pages[i]);
 695                         }
 696                         kfree(async_extent->pages);
 697                         async_extent->nr_pages = 0;
 698                         async_extent->pages = NULL;
 699
 700                         if (ret == -ENOSPC) {
 701                                 unlock_extent(io_tree, async_extent->start,
 702                                               async_extent->start +
 703                                               async_extent->ram_size - 1);
 704                                 goto retry;
 705                         }
 706                         goto out_free;
 707                 }
 708
 709                 /*
 710                  * here we're doing allocation and writeback of the
 711                  * compressed pages
 712                  */
 713                 btrfs_drop_extent_cache(inode, async_extent->start,
 714                                         async_extent->start +
 715                                         async_extent->ram_size - 1, 0);
 716
 717                 em = alloc_extent_map();
 718                 if (!em) {
 719                         ret = -ENOMEM;
 720                         goto out_free_reserve;
 721                 }
 722                 em->start = async_extent->start;
 723                 em->len = async_extent->ram_size;
 724                 em->orig_start = em->start;
 725                 em->mod_start = em->start;
 726                 em->mod_len = em->len;
 727
 728                 em->block_start = ins.objectid;
 729                 em->block_len = ins.offset;
 730                 em->orig_block_len = ins.offset;
 731                 em->ram_bytes = async_extent->ram_size;
 732                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 733                 em->compress_type = async_extent->compress_type;
 734                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 735                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 736                 em->generation = -1;
 737
 738                 while (1) {
 739                         write_lock(&em_tree->lock);
 740                         ret = add_extent_mapping(em_tree, em, 1);
 741                         write_unlock(&em_tree->lock);
 742                         if (ret != -EEXIST) {
 743                                 free_extent_map(em);
 744                                 break;
 745                         }
 746                         btrfs_drop_extent_cache(inode, async_extent->start,
 747                                                 async_extent->start +
 748                                                 async_extent->ram_size - 1, 0);
 749                 }
 750
 751                 if (ret)
 752                         goto out_free_reserve;
 753
 754                 ret = btrfs_add_ordered_extent_compress(inode,
 755                                                 async_extent->start,
 756                                                 ins.objectid,
 757                                                 async_extent->ram_size,
 758                                                 ins.offset,
 759                                                 BTRFS_ORDERED_COMPRESSED,
 760                                                 async_extent->compress_type);
 761                 if (ret)
 762                         goto out_free_reserve;
 763
 764                 /*
 765                  * clear dirty, set writeback and unlock the pages.
 766                  */
 767                 extent_clear_unlock_delalloc(inode, async_extent->start,
 768                                 async_extent->start +
 769                                 async_extent->ram_size - 1,
 770                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 771                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 772                                 PAGE_SET_WRITEBACK);
 773                 ret = btrfs_submit_compressed_write(inode,
 774                                     async_extent->start,
 775                                     async_extent->ram_size,
 776                                     ins.objectid,
 777                                     ins.offset, async_extent->pages,
 778                                     async_extent->nr_pages);
 779                 alloc_hint = ins.objectid + ins.offset;
 780                 kfree(async_extent);
 781                 if (ret)
 782                         goto out;
 783                 cond_resched();
 784         }
 785         ret = 0;
 786 out:
 787         return ret;
 788 out_free_reserve:
 789         btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
 790 out_free:
 791         extent_clear_unlock_delalloc(inode, async_extent->start,
 792                                      async_extent->start +
 793                                      async_extent->ram_size - 1,
 794                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 795                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 796                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 797                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
 798         kfree(async_extent);
 799         goto again;
 800 }
 801
 802 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 803                                       u64 num_bytes)
 804 {
 805         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 806         struct extent_map *em;
 807         u64 alloc_hint = 0;
 808
 809         read_lock(&em_tree->lock);
 810         em = search_extent_mapping(em_tree, start, num_bytes);
 811         if (em) {
 812                 /*
 813                  * if block start isn't an actual block number then find the
 814                  * first block in this inode and use that as a hint.  If that
 815                  * block is also bogus then just don't worry about it.
 816                  */
 817                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 818                         free_extent_map(em);
 819                         em = search_extent_mapping(em_tree, 0, 0);
 820                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 821                                 alloc_hint = em->block_start;
 822                         if (em)
 823                                 free_extent_map(em);
 824                 } else {
 825                         alloc_hint = em->block_start;
 826                         free_extent_map(em);
 827                 }
 828         }
 829         read_unlock(&em_tree->lock);
 830
 831         return alloc_hint;
 832 }
 833
 834 /*
 835  * when extent_io.c finds a delayed allocation range in the file,
 836  * the call backs end up in this code.  The basic idea is to
 837  * allocate extents on disk for the range, and create ordered data structs
 838  * in ram to track those extents.
 839  *
 840  * locked_page is the page that writepage had locked already.  We use
 841  * it to make sure we don't do extra locks or unlocks.
 842  *
 843  * *page_started is set to one if we unlock locked_page and do everything
 844  * required to start IO on it.  It may be clean and already done with
 845  * IO when we return.
 846  */
 847 static noinline int cow_file_range(struct inode *inode,
 848                                    struct page *locked_page,
 849                                    u64 start, u64 end, int *page_started,
 850                                    unsigned long *nr_written,
 851                                    int unlock)
 852 {
 853         struct btrfs_root *root = BTRFS_I(inode)->root;
 854         u64 alloc_hint = 0;
 855         u64 num_bytes;
 856         unsigned long ram_size;
 857         u64 disk_num_bytes;
 858         u64 cur_alloc_size;
 859         u64 blocksize = root->sectorsize;
 860         struct btrfs_key ins;
 861         struct extent_map *em;
 862         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 863         int ret = 0;
 864
 865         if (btrfs_is_free_space_inode(inode)) {
 866                 WARN_ON_ONCE(1);
 867                 ret = -EINVAL;
 868                 goto out_unlock;
 869         }
 870
 871         num_bytes = ALIGN(end - start + 1, blocksize);
 872         num_bytes = max(blocksize,  num_bytes);
 873         disk_num_bytes = num_bytes;
 874
 875         /* if this is a small write inside eof, kick off defrag */
 876         if (num_bytes < 64 * 1024 &&
 877             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 878                 btrfs_add_inode_defrag(NULL, inode);
 879
 880         if (start == 0) {
 881                 /* lets try to make an inline extent */
 882                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 883                                             NULL);
 884                 if (ret == 0) {
 885                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 886                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 887                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 888                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 889                                      PAGE_END_WRITEBACK);
 890
 891                         *nr_written = *nr_written +
 892                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 893                         *page_started = 1;
 894                         goto out;
 895                 } else if (ret < 0) {
 896                         goto out_unlock;
 897                 }
 898         }
 899
 900         BUG_ON(disk_num_bytes >
 901                btrfs_super_total_bytes(root->fs_info->super_copy));
 902
 903         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 904         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 905
 906         while (disk_num_bytes > 0) {
 907                 unsigned long op;
 908
 909                 cur_alloc_size = disk_num_bytes;
 910                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 911                                            root->sectorsize, 0, alloc_hint,
 912                                            &ins, 1);
 913                 if (ret < 0)
 914                         goto out_unlock;
 915
 916                 em = alloc_extent_map();
 917                 if (!em) {
 918                         ret = -ENOMEM;
 919                         goto out_reserve;
 920                 }
 921                 em->start = start;
 922                 em->orig_start = em->start;
 923                 ram_size = ins.offset;
 924                 em->len = ins.offset;
 925                 em->mod_start = em->start;
 926                 em->mod_len = em->len;
 927
 928                 em->block_start = ins.objectid;
 929                 em->block_len = ins.offset;
 930                 em->orig_block_len = ins.offset;
 931                 em->ram_bytes = ram_size;
 932                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 933                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 934                 em->generation = -1;
 935
 936                 while (1) {
 937                         write_lock(&em_tree->lock);
 938                         ret = add_extent_mapping(em_tree, em, 1);
 939                         write_unlock(&em_tree->lock);
 940                         if (ret != -EEXIST) {
 941                                 free_extent_map(em);
 942                                 break;
 943                         }
 944                         btrfs_drop_extent_cache(inode, start,
 945                                                 start + ram_size - 1, 0);
 946                 }
 947                 if (ret)
 948                         goto out_reserve;
 949
 950                 cur_alloc_size = ins.offset;
 951                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 952                                                ram_size, cur_alloc_size, 0);
 953                 if (ret)
 954                         goto out_reserve;
 955
 956                 if (root->root_key.objectid ==
 957                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 958                         ret = btrfs_reloc_clone_csums(inode, start,
 959                                                       cur_alloc_size);
 960                         if (ret)
 961                                 goto out_reserve;
 962                 }
 963
 964                 if (disk_num_bytes < cur_alloc_size)
 965                         break;
 966
 967                 /* we're not doing compressed IO, don't unlock the first
 968                  * page (which the caller expects to stay locked), don't
 969                  * clear any dirty bits and don't set any writeback bits
 970                  *
 971                  * Do set the Private2 bit so we know this page was properly
 972                  * setup for writepage
 973                  */
 974                 op = unlock ? PAGE_UNLOCK : 0;
 975                 op |= PAGE_SET_PRIVATE2;
 976
 977                 extent_clear_unlock_delalloc(inode, start,
 978                                              start + ram_size - 1, locked_page,
 979                                              EXTENT_LOCKED | EXTENT_DELALLOC,
 980                                              op);
 981                 disk_num_bytes -= cur_alloc_size;
 982                 num_bytes -= cur_alloc_size;
 983                 alloc_hint = ins.objectid + ins.offset;
 984                 start += cur_alloc_size;
 985         }
 986 out:
 987         return ret;
 988
 989 out_reserve:
 990         btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
 991 out_unlock:
 992         extent_clear_unlock_delalloc(inode, start, end, locked_page,
 993                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
 994                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
 995                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 996                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
 997         goto out;
 998 }
 999
1000 /*
1001  * work queue call back to started compression on a file and pages
1002  */
1003 static noinline void async_cow_start(struct btrfs_work *work)
1004 {
1005         struct async_cow *async_cow;
1006         int num_added = 0;
1007         async_cow = container_of(work, struct async_cow, work);
1008
1009         compress_file_range(async_cow->inode, async_cow->locked_page,
1010                             async_cow->start, async_cow->end, async_cow,
1011                             &num_added);
1012         if (num_added == 0) {
1013                 btrfs_add_delayed_iput(async_cow->inode);
1014                 async_cow->inode = NULL;
1015         }
1016 }
1017
1018 /*
1019  * work queue call back to submit previously compressed pages
1020  */
1021 static noinline void async_cow_submit(struct btrfs_work *work)
1022 {
1023         struct async_cow *async_cow;
1024         struct btrfs_root *root;
1025         unsigned long nr_pages;
1026
1027         async_cow = container_of(work, struct async_cow, work);
1028
1029         root = async_cow->root;
1030         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1031                 PAGE_CACHE_SHIFT;
1032
1033         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1034             5 * 1024 * 1024 &&
1035             waitqueue_active(&root->fs_info->async_submit_wait))
1036                 wake_up(&root->fs_info->async_submit_wait);
1037
1038         if (async_cow->inode)
1039                 submit_compressed_extents(async_cow->inode, async_cow);
1040 }
1041
1042 static noinline void async_cow_free(struct btrfs_work *work)
1043 {
1044         struct async_cow *async_cow;
1045         async_cow = container_of(work, struct async_cow, work);
1046         if (async_cow->inode)
1047                 btrfs_add_delayed_iput(async_cow->inode);
1048         kfree(async_cow);
1049 }
1050
1051 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1052                                 u64 start, u64 end, int *page_started,
1053                                 unsigned long *nr_written)
1054 {
1055         struct async_cow *async_cow;
1056         struct btrfs_root *root = BTRFS_I(inode)->root;
1057         unsigned long nr_pages;
1058         u64 cur_end;
1059         int limit = 10 * 1024 * 1024;
1060
1061         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1062                          1, 0, NULL, GFP_NOFS);
1063         while (start < end) {
1064                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1065                 BUG_ON(!async_cow); /* -ENOMEM */
1066                 async_cow->inode = igrab(inode);
1067                 async_cow->root = root;
1068                 async_cow->locked_page = locked_page;
1069                 async_cow->start = start;
1070
1071                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
1072                         cur_end = end;
1073                 else
1074                         cur_end = min(end, start + 512 * 1024 - 1);
1075
1076                 async_cow->end = cur_end;
1077                 INIT_LIST_HEAD(&async_cow->extents);
1078
1079                 btrfs_init_work(&async_cow->work, async_cow_start,
1080                                 async_cow_submit, async_cow_free);
1081
1082                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1083                         PAGE_CACHE_SHIFT;
1084                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1085
1086                 btrfs_queue_work(root->fs_info->delalloc_workers,
1087                                  &async_cow->work);
1088
1089                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1090                         wait_event(root->fs_info->async_submit_wait,
1091                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1092                             limit));
1093                 }
1094
1095                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1096                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1097                         wait_event(root->fs_info->async_submit_wait,
1098                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1099                            0));
1100                 }
1101
1102                 *nr_written += nr_pages;
1103                 start = cur_end + 1;
1104         }
1105         *page_started = 1;
1106         return 0;
1107 }
1108
1109 static noinline int csum_exist_in_range(struct btrfs_root *root,
1110                                         u64 bytenr, u64 num_bytes)
1111 {
1112         int ret;
1113         struct btrfs_ordered_sum *sums;
1114         LIST_HEAD(list);
1115
1116         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1117                                        bytenr + num_bytes - 1, &list, 0);
1118         if (ret == 0 && list_empty(&list))
1119                 return 0;
1120
1121         while (!list_empty(&list)) {
1122                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1123                 list_del(&sums->list);
1124                 kfree(sums);
1125         }
1126         return 1;
1127 }
1128
1129 /*
1130  * when nowcow writeback call back.  This checks for snapshots or COW copies
1131  * of the extents that exist in the file, and COWs the file as required.
1132  *
1133  * If no cow copies or snapshots exist, we write directly to the existing
1134  * blocks on disk
1135  */
1136 static noinline int run_delalloc_nocow(struct inode *inode,
1137                                        struct page *locked_page,
1138                               u64 start, u64 end, int *page_started, int force,
1139                               unsigned long *nr_written)
1140 {
1141         struct btrfs_root *root = BTRFS_I(inode)->root;
1142         struct btrfs_trans_handle *trans;
1143         struct extent_buffer *leaf;
1144         struct btrfs_path *path;
1145         struct btrfs_file_extent_item *fi;
1146         struct btrfs_key found_key;
1147         u64 cow_start;
1148         u64 cur_offset;
1149         u64 extent_end;
1150         u64 extent_offset;
1151         u64 disk_bytenr;
1152         u64 num_bytes;
1153         u64 disk_num_bytes;
1154         u64 ram_bytes;
1155         int extent_type;
1156         int ret, err;
1157         int type;
1158         int nocow;
1159         int check_prev = 1;
1160         bool nolock;
1161         u64 ino = btrfs_ino(inode);
1162
1163         path = btrfs_alloc_path();
1164         if (!path) {
1165                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1166                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1167                                              EXTENT_DO_ACCOUNTING |
1168                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1169                                              PAGE_CLEAR_DIRTY |
1170                                              PAGE_SET_WRITEBACK |
1171                                              PAGE_END_WRITEBACK);
1172                 return -ENOMEM;
1173         }
1174
1175         nolock = btrfs_is_free_space_inode(inode);
1176
1177         if (nolock)
1178                 trans = btrfs_join_transaction_nolock(root);
1179         else
1180                 trans = btrfs_join_transaction(root);
1181
1182         if (IS_ERR(trans)) {
1183                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1184                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1185                                              EXTENT_DO_ACCOUNTING |
1186                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1187                                              PAGE_CLEAR_DIRTY |
1188                                              PAGE_SET_WRITEBACK |
1189                                              PAGE_END_WRITEBACK);
1190                 btrfs_free_path(path);
1191                 return PTR_ERR(trans);
1192         }
1193
1194         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1195
1196         cow_start = (u64)-1;
1197         cur_offset = start;
1198         while (1) {
1199                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1200                                                cur_offset, 0);
1201                 if (ret < 0)
1202                         goto error;
1203                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1204                         leaf = path->nodes[0];
1205                         btrfs_item_key_to_cpu(leaf, &found_key,
1206                                               path->slots[0] - 1);
1207                         if (found_key.objectid == ino &&
1208                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1209                                 path->slots[0]--;
1210                 }
1211                 check_prev = 0;
1212 next_slot:
1213                 leaf = path->nodes[0];
1214                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1215                         ret = btrfs_next_leaf(root, path);
1216                         if (ret < 0)
1217                                 goto error;
1218                         if (ret > 0)
1219                                 break;
1220                         leaf = path->nodes[0];
1221                 }
1222
1223                 nocow = 0;
1224                 disk_bytenr = 0;
1225                 num_bytes = 0;
1226                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1227
1228                 if (found_key.objectid > ino ||
1229                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1230                     found_key.offset > end)
1231                         break;
1232
1233                 if (found_key.offset > cur_offset) {
1234                         extent_end = found_key.offset;
1235                         extent_type = 0;
1236                         goto out_check;
1237                 }
1238
1239                 fi = btrfs_item_ptr(leaf, path->slots[0],
1240                                     struct btrfs_file_extent_item);
1241                 extent_type = btrfs_file_extent_type(leaf, fi);
1242
1243                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1244                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1245                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1246                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1247                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1248                         extent_end = found_key.offset +
1249                                 btrfs_file_extent_num_bytes(leaf, fi);
1250                         disk_num_bytes =
1251                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1252                         if (extent_end <= start) {
1253                                 path->slots[0]++;
1254                                 goto next_slot;
1255                         }
1256                         if (disk_bytenr == 0)
1257                                 goto out_check;
1258                         if (btrfs_file_extent_compression(leaf, fi) ||
1259                             btrfs_file_extent_encryption(leaf, fi) ||
1260                             btrfs_file_extent_other_encoding(leaf, fi))
1261                                 goto out_check;
1262                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1263                                 goto out_check;
1264                         if (btrfs_extent_readonly(root, disk_bytenr))
1265                                 goto out_check;
1266                         if (btrfs_cross_ref_exist(trans, root, ino,
1267                                                   found_key.offset -
1268                                                   extent_offset, disk_bytenr))
1269                                 goto out_check;
1270                         disk_bytenr += extent_offset;
1271                         disk_bytenr += cur_offset - found_key.offset;
1272                         num_bytes = min(end + 1, extent_end) - cur_offset;
1273                         /*
1274                          * force cow if csum exists in the range.
1275                          * this ensure that csum for a given extent are
1276                          * either valid or do not exist.
1277                          */
1278                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1279                                 goto out_check;
1280                         nocow = 1;
1281                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1282                         extent_end = found_key.offset +
1283                                 btrfs_file_extent_inline_len(leaf,
1284                                                      path->slots[0], fi);
1285                         extent_end = ALIGN(extent_end, root->sectorsize);
1286                 } else {
1287                         BUG_ON(1);
1288                 }
1289 out_check:
1290                 if (extent_end <= start) {
1291                         path->slots[0]++;
1292                         goto next_slot;
1293                 }
1294                 if (!nocow) {
1295                         if (cow_start == (u64)-1)
1296                                 cow_start = cur_offset;
1297                         cur_offset = extent_end;
1298                         if (cur_offset > end)
1299                                 break;
1300                         path->slots[0]++;
1301                         goto next_slot;
1302                 }
1303
1304                 btrfs_release_path(path);
1305                 if (cow_start != (u64)-1) {
1306                         ret = cow_file_range(inode, locked_page,
1307                                              cow_start, found_key.offset - 1,
1308                                              page_started, nr_written, 1);
1309                         if (ret)
1310                                 goto error;
1311                         cow_start = (u64)-1;
1312                 }
1313
1314                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1315                         struct extent_map *em;
1316                         struct extent_map_tree *em_tree;
1317                         em_tree = &BTRFS_I(inode)->extent_tree;
1318                         em = alloc_extent_map();
1319                         BUG_ON(!em); /* -ENOMEM */
1320                         em->start = cur_offset;
1321                         em->orig_start = found_key.offset - extent_offset;
1322                         em->len = num_bytes;
1323                         em->block_len = num_bytes;
1324                         em->block_start = disk_bytenr;
1325                         em->orig_block_len = disk_num_bytes;
1326                         em->ram_bytes = ram_bytes;
1327                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1328                         em->mod_start = em->start;
1329                         em->mod_len = em->len;
1330                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1331                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1332                         em->generation = -1;
1333                         while (1) {
1334                                 write_lock(&em_tree->lock);
1335                                 ret = add_extent_mapping(em_tree, em, 1);
1336                                 write_unlock(&em_tree->lock);
1337                                 if (ret != -EEXIST) {
1338                                         free_extent_map(em);
1339                                         break;
1340                                 }
1341                                 btrfs_drop_extent_cache(inode, em->start,
1342                                                 em->start + em->len - 1, 0);
1343                         }
1344                         type = BTRFS_ORDERED_PREALLOC;
1345                 } else {
1346                         type = BTRFS_ORDERED_NOCOW;
1347                 }
1348
1349                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1350                                                num_bytes, num_bytes, type);
1351                 BUG_ON(ret); /* -ENOMEM */
1352
1353                 if (root->root_key.objectid ==
1354                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1355                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1356                                                       num_bytes);
1357                         if (ret)
1358                                 goto error;
1359                 }
1360
1361                 extent_clear_unlock_delalloc(inode, cur_offset,
1362                                              cur_offset + num_bytes - 1,
1363                                              locked_page, EXTENT_LOCKED |
1364                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1365                                              PAGE_SET_PRIVATE2);
1366                 cur_offset = extent_end;
1367                 if (cur_offset > end)
1368                         break;
1369         }
1370         btrfs_release_path(path);
1371
1372         if (cur_offset <= end && cow_start == (u64)-1) {
1373                 cow_start = cur_offset;
1374                 cur_offset = end;
1375         }
1376
1377         if (cow_start != (u64)-1) {
1378                 ret = cow_file_range(inode, locked_page, cow_start, end,
1379                                      page_started, nr_written, 1);
1380                 if (ret)
1381                         goto error;
1382         }
1383
1384 error:
1385         err = btrfs_end_transaction(trans, root);
1386         if (!ret)
1387                 ret = err;
1388
1389         if (ret && cur_offset < end)
1390                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1391                                              locked_page, EXTENT_LOCKED |
1392                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1393                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1394                                              PAGE_CLEAR_DIRTY |
1395                                              PAGE_SET_WRITEBACK |
1396                                              PAGE_END_WRITEBACK);
1397         btrfs_free_path(path);
1398         return ret;
1399 }
1400
1401 /*
1402  * extent_io.c call back to do delayed allocation processing
1403  */
1404 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1405                               u64 start, u64 end, int *page_started,
1406                               unsigned long *nr_written)
1407 {
1408         int ret;
1409         struct btrfs_root *root = BTRFS_I(inode)->root;
1410
1411         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) {
1412                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1413                                          page_started, 1, nr_written);
1414         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC) {
1415                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1416                                          page_started, 0, nr_written);
1417         } else if (!btrfs_test_opt(root, COMPRESS) &&
1418                    !(BTRFS_I(inode)->force_compress) &&
1419                    !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS)) {
1420                 ret = cow_file_range(inode, locked_page, start, end,
1421                                       page_started, nr_written, 1);
1422         } else {
1423                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1424                         &BTRFS_I(inode)->runtime_flags);
1425                 ret = cow_file_range_async(inode, locked_page, start, end,
1426                                            page_started, nr_written);
1427         }
1428         return ret;
1429 }
1430
1431 static void btrfs_split_extent_hook(struct inode *inode,
1432                                     struct extent_state *orig, u64 split)
1433 {
1434         /* not delalloc, ignore it */
1435         if (!(orig->state & EXTENT_DELALLOC))
1436                 return;
1437
1438         spin_lock(&BTRFS_I(inode)->lock);
1439         BTRFS_I(inode)->outstanding_extents++;
1440         spin_unlock(&BTRFS_I(inode)->lock);
1441 }
1442
1443 /*
1444  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1445  * extents so we can keep track of new extents that are just merged onto old
1446  * extents, such as when we are doing sequential writes, so we can properly
1447  * account for the metadata space we'll need.
1448  */
1449 static void btrfs_merge_extent_hook(struct inode *inode,
1450                                     struct extent_state *new,
1451                                     struct extent_state *other)
1452 {
1453         /* not delalloc, ignore it */
1454         if (!(other->state & EXTENT_DELALLOC))
1455                 return;
1456
1457         spin_lock(&BTRFS_I(inode)->lock);
1458         BTRFS_I(inode)->outstanding_extents--;
1459         spin_unlock(&BTRFS_I(inode)->lock);
1460 }
1461
1462 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1463                                       struct inode *inode)
1464 {
1465         spin_lock(&root->delalloc_lock);
1466         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1467                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1468                               &root->delalloc_inodes);
1469                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1470                         &BTRFS_I(inode)->runtime_flags);
1471                 root->nr_delalloc_inodes++;
1472                 if (root->nr_delalloc_inodes == 1) {
1473                         spin_lock(&root->fs_info->delalloc_root_lock);
1474                         BUG_ON(!list_empty(&root->delalloc_root));
1475                         list_add_tail(&root->delalloc_root,
1476                                       &root->fs_info->delalloc_roots);
1477                         spin_unlock(&root->fs_info->delalloc_root_lock);
1478                 }
1479         }
1480         spin_unlock(&root->delalloc_lock);
1481 }
1482
1483 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1484                                      struct inode *inode)
1485 {
1486         spin_lock(&root->delalloc_lock);
1487         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1488                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1489                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1490                           &BTRFS_I(inode)->runtime_flags);
1491                 root->nr_delalloc_inodes--;
1492                 if (!root->nr_delalloc_inodes) {
1493                         spin_lock(&root->fs_info->delalloc_root_lock);
1494                         BUG_ON(list_empty(&root->delalloc_root));
1495                         list_del_init(&root->delalloc_root);
1496                         spin_unlock(&root->fs_info->delalloc_root_lock);
1497                 }
1498         }
1499         spin_unlock(&root->delalloc_lock);
1500 }
1501
1502 /*
1503  * extent_io.c set_bit_hook, used to track delayed allocation
1504  * bytes in this file, and to maintain the list of inodes that
1505  * have pending delalloc work to be done.
1506  */
1507 static void btrfs_set_bit_hook(struct inode *inode,
1508                                struct extent_state *state, unsigned long *bits)
1509 {
1510
1511         /*
1512          * set_bit and clear bit hooks normally require _irqsave/restore
1513          * but in this case, we are only testing for the DELALLOC
1514          * bit, which is only set or cleared with irqs on
1515          */
1516         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1517                 struct btrfs_root *root = BTRFS_I(inode)->root;
1518                 u64 len = state->end + 1 - state->start;
1519                 bool do_list = !btrfs_is_free_space_inode(inode);
1520
1521                 if (*bits & EXTENT_FIRST_DELALLOC) {
1522                         *bits &= ~EXTENT_FIRST_DELALLOC;
1523                 } else {
1524                         spin_lock(&BTRFS_I(inode)->lock);
1525                         BTRFS_I(inode)->outstanding_extents++;
1526                         spin_unlock(&BTRFS_I(inode)->lock);
1527                 }
1528
1529                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1530                                      root->fs_info->delalloc_batch);
1531                 spin_lock(&BTRFS_I(inode)->lock);
1532                 BTRFS_I(inode)->delalloc_bytes += len;
1533                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1534                                          &BTRFS_I(inode)->runtime_flags))
1535                         btrfs_add_delalloc_inodes(root, inode);
1536                 spin_unlock(&BTRFS_I(inode)->lock);
1537         }
1538 }
1539
1540 /*
1541  * extent_io.c clear_bit_hook, see set_bit_hook for why
1542  */
1543 static void btrfs_clear_bit_hook(struct inode *inode,
1544                                  struct extent_state *state,
1545                                  unsigned long *bits)
1546 {
1547         /*
1548          * set_bit and clear bit hooks normally require _irqsave/restore
1549          * but in this case, we are only testing for the DELALLOC
1550          * bit, which is only set or cleared with irqs on
1551          */
1552         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1553                 struct btrfs_root *root = BTRFS_I(inode)->root;
1554                 u64 len = state->end + 1 - state->start;
1555                 bool do_list = !btrfs_is_free_space_inode(inode);
1556
1557                 if (*bits & EXTENT_FIRST_DELALLOC) {
1558                         *bits &= ~EXTENT_FIRST_DELALLOC;
1559                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1560                         spin_lock(&BTRFS_I(inode)->lock);
1561                         BTRFS_I(inode)->outstanding_extents--;
1562                         spin_unlock(&BTRFS_I(inode)->lock);
1563                 }
1564
1565                 /*
1566                  * We don't reserve metadata space for space cache inodes so we
1567                  * don't need to call dellalloc_release_metadata if there is an
1568                  * error.
1569                  */
1570                 if (*bits & EXTENT_DO_ACCOUNTING &&
1571                     root != root->fs_info->tree_root)
1572                         btrfs_delalloc_release_metadata(inode, len);
1573
1574                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1575                     && do_list && !(state->state & EXTENT_NORESERVE))
1576                         btrfs_free_reserved_data_space(inode, len);
1577
1578                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1579                                      root->fs_info->delalloc_batch);
1580                 spin_lock(&BTRFS_I(inode)->lock);
1581                 BTRFS_I(inode)->delalloc_bytes -= len;
1582                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1583                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1584                              &BTRFS_I(inode)->runtime_flags))
1585                         btrfs_del_delalloc_inode(root, inode);
1586                 spin_unlock(&BTRFS_I(inode)->lock);
1587         }
1588 }
1589
1590 /*
1591  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1592  * we don't create bios that span stripes or chunks
1593  */
1594 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1595                          size_t size, struct bio *bio,
1596                          unsigned long bio_flags)
1597 {
1598         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1599         u64 logical = (u64)bio->bi_sector << 9;
1600         u64 length = 0;
1601         u64 map_length;
1602         int ret;
1603
1604         if (bio_flags & EXTENT_BIO_COMPRESSED)
1605                 return 0;
1606
1607         length = bio->bi_size;
1608         map_length = length;
1609         ret = btrfs_map_block(root->fs_info, rw, logical,
1610                               &map_length, NULL, 0);
1611         /* Will always return 0 with map_multi == NULL */
1612         BUG_ON(ret < 0);
1613         if (map_length < length + size)
1614                 return 1;
1615         return 0;
1616 }
1617
1618 /*
1619  * in order to insert checksums into the metadata in large chunks,
1620  * we wait until bio submission time.   All the pages in the bio are
1621  * checksummed and sums are attached onto the ordered extent record.
1622  *
1623  * At IO completion time the cums attached on the ordered extent record
1624  * are inserted into the btree
1625  */
1626 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1627                                     struct bio *bio, int mirror_num,
1628                                     unsigned long bio_flags,
1629                                     u64 bio_offset)
1630 {
1631         struct btrfs_root *root = BTRFS_I(inode)->root;
1632         int ret = 0;
1633
1634         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1635         BUG_ON(ret); /* -ENOMEM */
1636         return 0;
1637 }
1638
1639 /*
1640  * in order to insert checksums into the metadata in large chunks,
1641  * we wait until bio submission time.   All the pages in the bio are
1642  * checksummed and sums are attached onto the ordered extent record.
1643  *
1644  * At IO completion time the cums attached on the ordered extent record
1645  * are inserted into the btree
1646  */
1647 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1648                           int mirror_num, unsigned long bio_flags,
1649                           u64 bio_offset)
1650 {
1651         struct btrfs_root *root = BTRFS_I(inode)->root;
1652         int ret;
1653
1654         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1655         if (ret)
1656                 bio_endio(bio, ret);
1657         return ret;
1658 }
1659
1660 /*
1661  * extent_io.c submission hook. This does the right thing for csum calculation
1662  * on write, or reading the csums from the tree before a read
1663  */
1664 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1665                           int mirror_num, unsigned long bio_flags,
1666                           u64 bio_offset)
1667 {
1668         struct btrfs_root *root = BTRFS_I(inode)->root;
1669         int ret = 0;
1670         int skip_sum;
1671         int metadata = 0;
1672         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1673
1674         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1675
1676         if (btrfs_is_free_space_inode(inode))
1677                 metadata = 2;
1678
1679         if (!(rw & REQ_WRITE)) {
1680                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1681                 if (ret)
1682                         goto out;
1683
1684                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1685                         ret = btrfs_submit_compressed_read(inode, bio,
1686                                                            mirror_num,
1687                                                            bio_flags);
1688                         goto out;
1689                 } else if (!skip_sum) {
1690                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1691                         if (ret)
1692                                 goto out;
1693                 }
1694                 goto mapit;
1695         } else if (async && !skip_sum) {
1696                 /* csum items have already been cloned */
1697                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1698                         goto mapit;
1699                 /* we're doing a write, do the async checksumming */
1700                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1701                                    inode, rw, bio, mirror_num,
1702                                    bio_flags, bio_offset,
1703                                    __btrfs_submit_bio_start,
1704                                    __btrfs_submit_bio_done);
1705                 goto out;
1706         } else if (!skip_sum) {
1707                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1708                 if (ret)
1709                         goto out;
1710         }
1711
1712 mapit:
1713         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1714
1715 out:
1716         if (ret < 0)
1717                 bio_endio(bio, ret);
1718         return ret;
1719 }
1720
1721 /*
1722  * given a list of ordered sums record them in the inode.  This happens
1723  * at IO completion time based on sums calculated at bio submission time.
1724  */
1725 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1726                              struct inode *inode, u64 file_offset,
1727                              struct list_head *list)
1728 {
1729         struct btrfs_ordered_sum *sum;
1730
1731         list_for_each_entry(sum, list, list) {
1732                 trans->adding_csums = 1;
1733                 btrfs_csum_file_blocks(trans,
1734                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1735                 trans->adding_csums = 0;
1736         }
1737         return 0;
1738 }
1739
1740 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1741                               struct extent_state **cached_state)
1742 {
1743         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1744         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1745                                    cached_state, GFP_NOFS);
1746 }
1747
1748 /* see btrfs_writepage_start_hook for details on why this is required */
1749 struct btrfs_writepage_fixup {
1750         struct page *page;
1751         struct btrfs_work work;
1752 };
1753
1754 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1755 {
1756         struct btrfs_writepage_fixup *fixup;
1757         struct btrfs_ordered_extent *ordered;
1758         struct extent_state *cached_state = NULL;
1759         struct page *page;
1760         struct inode *inode;
1761         u64 page_start;
1762         u64 page_end;
1763         int ret;
1764
1765         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1766         page = fixup->page;
1767 again:
1768         lock_page(page);
1769         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1770                 ClearPageChecked(page);
1771                 goto out_page;
1772         }
1773
1774         inode = page->mapping->host;
1775         page_start = page_offset(page);
1776         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1777
1778         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1779                          &cached_state);
1780
1781         /* already ordered? We're done */
1782         if (PagePrivate2(page))
1783                 goto out;
1784
1785         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1786         if (ordered) {
1787                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1788                                      page_end, &cached_state, GFP_NOFS);
1789                 unlock_page(page);
1790                 btrfs_start_ordered_extent(inode, ordered, 1);
1791                 btrfs_put_ordered_extent(ordered);
1792                 goto again;
1793         }
1794
1795         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1796         if (ret) {
1797                 mapping_set_error(page->mapping, ret);
1798                 end_extent_writepage(page, ret, page_start, page_end);
1799                 ClearPageChecked(page);
1800                 goto out;
1801          }
1802
1803         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1804         ClearPageChecked(page);
1805         set_page_dirty(page);
1806 out:
1807         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1808                              &cached_state, GFP_NOFS);
1809 out_page:
1810         unlock_page(page);
1811         page_cache_release(page);
1812         kfree(fixup);
1813 }
1814
1815 /*
1816  * There are a few paths in the higher layers of the kernel that directly
1817  * set the page dirty bit without asking the filesystem if it is a
1818  * good idea.  This causes problems because we want to make sure COW
1819  * properly happens and the data=ordered rules are followed.
1820  *
1821  * In our case any range that doesn't have the ORDERED bit set
1822  * hasn't been properly setup for IO.  We kick off an async process
1823  * to fix it up.  The async helper will wait for ordered extents, set
1824  * the delalloc bit and make it safe to write the page.
1825  */
1826 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1827 {
1828         struct inode *inode = page->mapping->host;
1829         struct btrfs_writepage_fixup *fixup;
1830         struct btrfs_root *root = BTRFS_I(inode)->root;
1831
1832         /* this page is properly in the ordered list */
1833         if (TestClearPagePrivate2(page))
1834                 return 0;
1835
1836         if (PageChecked(page))
1837                 return -EAGAIN;
1838
1839         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1840         if (!fixup)
1841                 return -EAGAIN;
1842
1843         SetPageChecked(page);
1844         page_cache_get(page);
1845         btrfs_init_work(&fixup->work, btrfs_writepage_fixup_worker, NULL, NULL);
1846         fixup->page = page;
1847         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
1848         return -EBUSY;
1849 }
1850
1851 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1852                                        struct inode *inode, u64 file_pos,
1853                                        u64 disk_bytenr, u64 disk_num_bytes,
1854                                        u64 num_bytes, u64 ram_bytes,
1855                                        u8 compression, u8 encryption,
1856                                        u16 other_encoding, int extent_type)
1857 {
1858         struct btrfs_root *root = BTRFS_I(inode)->root;
1859         struct btrfs_file_extent_item *fi;
1860         struct btrfs_path *path;
1861         struct extent_buffer *leaf;
1862         struct btrfs_key ins;
1863         int extent_inserted = 0;
1864         int ret;
1865
1866         path = btrfs_alloc_path();
1867         if (!path)
1868                 return -ENOMEM;
1869
1870         /*
1871          * we may be replacing one extent in the tree with another.
1872          * The new extent is pinned in the extent map, and we don't want
1873          * to drop it from the cache until it is completely in the btree.
1874          *
1875          * So, tell btrfs_drop_extents to leave this extent in the cache.
1876          * the caller is expected to unpin it and allow it to be merged
1877          * with the others.
1878          */
1879         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
1880                                    file_pos + num_bytes, NULL, 0,
1881                                    1, sizeof(*fi), &extent_inserted);
1882         if (ret)
1883                 goto out;
1884
1885         if (!extent_inserted) {
1886                 ins.objectid = btrfs_ino(inode);
1887                 ins.offset = file_pos;
1888                 ins.type = BTRFS_EXTENT_DATA_KEY;
1889
1890                 path->leave_spinning = 1;
1891                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
1892                                               sizeof(*fi));
1893                 if (ret)
1894                         goto out;
1895         }
1896         leaf = path->nodes[0];
1897         fi = btrfs_item_ptr(leaf, path->slots[0],
1898                             struct btrfs_file_extent_item);
1899         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1900         btrfs_set_file_extent_type(leaf, fi, extent_type);
1901         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1902         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1903         btrfs_set_file_extent_offset(leaf, fi, 0);
1904         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1905         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1906         btrfs_set_file_extent_compression(leaf, fi, compression);
1907         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1908         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1909
1910         btrfs_mark_buffer_dirty(leaf);
1911         btrfs_release_path(path);
1912
1913         inode_add_bytes(inode, num_bytes);
1914
1915         ins.objectid = disk_bytenr;
1916         ins.offset = disk_num_bytes;
1917         ins.type = BTRFS_EXTENT_ITEM_KEY;
1918         ret = btrfs_alloc_reserved_file_extent(trans, root,
1919                                         root->root_key.objectid,
1920                                         btrfs_ino(inode), file_pos, &ins);
1921 out:
1922         btrfs_free_path(path);
1923
1924         return ret;
1925 }
1926
1927 /* snapshot-aware defrag */
1928 struct sa_defrag_extent_backref {
1929         struct rb_node node;
1930         struct old_sa_defrag_extent *old;
1931         u64 root_id;
1932         u64 inum;
1933         u64 file_pos;
1934         u64 extent_offset;
1935         u64 num_bytes;
1936         u64 generation;
1937 };
1938
1939 struct old_sa_defrag_extent {
1940         struct list_head list;
1941         struct new_sa_defrag_extent *new;
1942
1943         u64 extent_offset;
1944         u64 bytenr;
1945         u64 offset;
1946         u64 len;
1947         int count;
1948 };
1949
1950 struct new_sa_defrag_extent {
1951         struct rb_root root;
1952         struct list_head head;
1953         struct btrfs_path *path;
1954         struct inode *inode;
1955         u64 file_pos;
1956         u64 len;
1957         u64 bytenr;
1958         u64 disk_len;
1959         u8 compress_type;
1960 };
1961
1962 static int backref_comp(struct sa_defrag_extent_backref *b1,
1963                         struct sa_defrag_extent_backref *b2)
1964 {
1965         if (b1->root_id < b2->root_id)
1966                 return -1;
1967         else if (b1->root_id > b2->root_id)
1968                 return 1;
1969
1970         if (b1->inum < b2->inum)
1971                 return -1;
1972         else if (b1->inum > b2->inum)
1973                 return 1;
1974
1975         if (b1->file_pos < b2->file_pos)
1976                 return -1;
1977         else if (b1->file_pos > b2->file_pos)
1978                 return 1;
1979
1980         /*
1981          * [------------------------------] ===> (a range of space)
1982          *     |<--->|   |<---->| =============> (fs/file tree A)
1983          * |<---------------------------->| ===> (fs/file tree B)
1984          *
1985          * A range of space can refer to two file extents in one tree while
1986          * refer to only one file extent in another tree.
1987          *
1988          * So we may process a disk offset more than one time(two extents in A)
1989          * and locate at the same extent(one extent in B), then insert two same
1990          * backrefs(both refer to the extent in B).
1991          */
1992         return 0;
1993 }
1994
1995 static void backref_insert(struct rb_root *root,
1996                            struct sa_defrag_extent_backref *backref)
1997 {
1998         struct rb_node **p = &root->rb_node;
1999         struct rb_node *parent = NULL;
2000         struct sa_defrag_extent_backref *entry;
2001         int ret;
2002
2003         while (*p) {
2004                 parent = *p;
2005                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2006
2007                 ret = backref_comp(backref, entry);
2008                 if (ret < 0)
2009                         p = &(*p)->rb_left;
2010                 else
2011                         p = &(*p)->rb_right;
2012         }
2013
2014         rb_link_node(&backref->node, parent, p);
2015         rb_insert_color(&backref->node, root);
2016 }
2017
2018 /*
2019  * Note the backref might has changed, and in this case we just return 0.
2020  */
2021 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2022                                        void *ctx)
2023 {
2024         struct btrfs_file_extent_item *extent;
2025         struct btrfs_fs_info *fs_info;
2026         struct old_sa_defrag_extent *old = ctx;
2027         struct new_sa_defrag_extent *new = old->new;
2028         struct btrfs_path *path = new->path;
2029         struct btrfs_key key;
2030         struct btrfs_root *root;
2031         struct sa_defrag_extent_backref *backref;
2032         struct extent_buffer *leaf;
2033         struct inode *inode = new->inode;
2034         int slot;
2035         int ret;
2036         u64 extent_offset;
2037         u64 num_bytes;
2038
2039         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2040             inum == btrfs_ino(inode))
2041                 return 0;
2042
2043         key.objectid = root_id;
2044         key.type = BTRFS_ROOT_ITEM_KEY;
2045         key.offset = (u64)-1;
2046
2047         fs_info = BTRFS_I(inode)->root->fs_info;
2048         root = btrfs_read_fs_root_no_name(fs_info, &key);
2049         if (IS_ERR(root)) {
2050                 if (PTR_ERR(root) == -ENOENT)
2051                         return 0;
2052                 WARN_ON(1);
2053                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2054                          inum, offset, root_id);
2055                 return PTR_ERR(root);
2056         }
2057
2058         key.objectid = inum;
2059         key.type = BTRFS_EXTENT_DATA_KEY;
2060         if (offset > (u64)-1 << 32)
2061                 key.offset = 0;
2062         else
2063                 key.offset = offset;
2064
2065         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2066         if (WARN_ON(ret < 0))
2067                 return ret;
2068         ret = 0;
2069
2070         while (1) {
2071                 cond_resched();
2072
2073                 leaf = path->nodes[0];
2074                 slot = path->slots[0];
2075
2076                 if (slot >= btrfs_header_nritems(leaf)) {
2077                         ret = btrfs_next_leaf(root, path);
2078                         if (ret < 0) {
2079                                 goto out;
2080                         } else if (ret > 0) {
2081                                 ret = 0;
2082                                 goto out;
2083                         }
2084                         continue;
2085                 }
2086
2087                 path->slots[0]++;
2088
2089                 btrfs_item_key_to_cpu(leaf, &key, slot);
2090
2091                 if (key.objectid > inum)
2092                         goto out;
2093
2094                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2095                         continue;
2096
2097                 extent = btrfs_item_ptr(leaf, slot,
2098                                         struct btrfs_file_extent_item);
2099
2100                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2101                         continue;
2102
2103                 /*
2104                  * 'offset' refers to the exact key.offset,
2105                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2106                  * (key.offset - extent_offset).
2107                  */
2108                 if (key.offset != offset)
2109                         continue;
2110
2111                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2112                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2113
2114                 if (extent_offset >= old->extent_offset + old->offset +
2115                     old->len || extent_offset + num_bytes <=
2116                     old->extent_offset + old->offset)
2117                         continue;
2118                 break;
2119         }
2120
2121         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2122         if (!backref) {
2123                 ret = -ENOENT;
2124                 goto out;
2125         }
2126
2127         backref->root_id = root_id;
2128         backref->inum = inum;
2129         backref->file_pos = offset;
2130         backref->num_bytes = num_bytes;
2131         backref->extent_offset = extent_offset;
2132         backref->generation = btrfs_file_extent_generation(leaf, extent);
2133         backref->old = old;
2134         backref_insert(&new->root, backref);
2135         old->count++;
2136 out:
2137         btrfs_release_path(path);
2138         WARN_ON(ret);
2139         return ret;
2140 }
2141
2142 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2143                                    struct new_sa_defrag_extent *new)
2144 {
2145         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2146         struct old_sa_defrag_extent *old, *tmp;
2147         int ret;
2148
2149         new->path = path;
2150
2151         list_for_each_entry_safe(old, tmp, &new->head, list) {
2152                 ret = iterate_inodes_from_logical(old->bytenr +
2153                                                   old->extent_offset, fs_info,
2154                                                   path, record_one_backref,
2155                                                   old);
2156                 if (ret < 0 && ret != -ENOENT)
2157                         return false;
2158
2159                 /* no backref to be processed for this extent */
2160                 if (!old->count) {
2161                         list_del(&old->list);
2162                         kfree(old);
2163                 }
2164         }
2165
2166         if (list_empty(&new->head))
2167                 return false;
2168
2169         return true;
2170 }
2171
2172 static int relink_is_mergable(struct extent_buffer *leaf,
2173                               struct btrfs_file_extent_item *fi,
2174                               struct new_sa_defrag_extent *new)
2175 {
2176         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2177                 return 0;
2178
2179         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2180                 return 0;
2181
2182         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2183                 return 0;
2184
2185         if (btrfs_file_extent_encryption(leaf, fi) ||
2186             btrfs_file_extent_other_encoding(leaf, fi))
2187                 return 0;
2188
2189         return 1;
2190 }
2191
2192 /*
2193  * Note the backref might has changed, and in this case we just return 0.
2194  */
2195 static noinline int relink_extent_backref(struct btrfs_path *path,
2196                                  struct sa_defrag_extent_backref *prev,
2197                                  struct sa_defrag_extent_backref *backref)
2198 {
2199         struct btrfs_file_extent_item *extent;
2200         struct btrfs_file_extent_item *item;
2201         struct btrfs_ordered_extent *ordered;
2202         struct btrfs_trans_handle *trans;
2203         struct btrfs_fs_info *fs_info;
2204         struct btrfs_root *root;
2205         struct btrfs_key key;
2206         struct extent_buffer *leaf;
2207         struct old_sa_defrag_extent *old = backref->old;
2208         struct new_sa_defrag_extent *new = old->new;
2209         struct inode *src_inode = new->inode;
2210         struct inode *inode;
2211         struct extent_state *cached = NULL;
2212         int ret = 0;
2213         u64 start;
2214         u64 len;
2215         u64 lock_start;
2216         u64 lock_end;
2217         bool merge = false;
2218         int index;
2219
2220         if (prev && prev->root_id == backref->root_id &&
2221             prev->inum == backref->inum &&
2222             prev->file_pos + prev->num_bytes == backref->file_pos)
2223                 merge = true;
2224
2225         /* step 1: get root */
2226         key.objectid = backref->root_id;
2227         key.type = BTRFS_ROOT_ITEM_KEY;
2228         key.offset = (u64)-1;
2229
2230         fs_info = BTRFS_I(src_inode)->root->fs_info;
2231         index = srcu_read_lock(&fs_info->subvol_srcu);
2232
2233         root = btrfs_read_fs_root_no_name(fs_info, &key);
2234         if (IS_ERR(root)) {
2235                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2236                 if (PTR_ERR(root) == -ENOENT)
2237                         return 0;
2238                 return PTR_ERR(root);
2239         }
2240
2241         if (btrfs_root_readonly(root)) {
2242                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2243                 return 0;
2244         }
2245
2246         /* step 2: get inode */
2247         key.objectid = backref->inum;
2248         key.type = BTRFS_INODE_ITEM_KEY;
2249         key.offset = 0;
2250
2251         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2252         if (IS_ERR(inode)) {
2253                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2254                 return 0;
2255         }
2256
2257         srcu_read_unlock(&fs_info->subvol_srcu, index);
2258
2259         /* step 3: relink backref */
2260         lock_start = backref->file_pos;
2261         lock_end = backref->file_pos + backref->num_bytes - 1;
2262         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2263                          0, &cached);
2264
2265         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2266         if (ordered) {
2267                 btrfs_put_ordered_extent(ordered);
2268                 goto out_unlock;
2269         }
2270
2271         trans = btrfs_join_transaction(root);
2272         if (IS_ERR(trans)) {
2273                 ret = PTR_ERR(trans);
2274                 goto out_unlock;
2275         }
2276
2277         key.objectid = backref->inum;
2278         key.type = BTRFS_EXTENT_DATA_KEY;
2279         key.offset = backref->file_pos;
2280
2281         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2282         if (ret < 0) {
2283                 goto out_free_path;
2284         } else if (ret > 0) {
2285                 ret = 0;
2286                 goto out_free_path;
2287         }
2288
2289         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2290                                 struct btrfs_file_extent_item);
2291
2292         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2293             backref->generation)
2294                 goto out_free_path;
2295
2296         btrfs_release_path(path);
2297
2298         start = backref->file_pos;
2299         if (backref->extent_offset < old->extent_offset + old->offset)
2300                 start += old->extent_offset + old->offset -
2301                          backref->extent_offset;
2302
2303         len = min(backref->extent_offset + backref->num_bytes,
2304                   old->extent_offset + old->offset + old->len);
2305         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2306
2307         ret = btrfs_drop_extents(trans, root, inode, start,
2308                                  start + len, 1);
2309         if (ret)
2310                 goto out_free_path;
2311 again:
2312         key.objectid = btrfs_ino(inode);
2313         key.type = BTRFS_EXTENT_DATA_KEY;
2314         key.offset = start;
2315
2316         path->leave_spinning = 1;
2317         if (merge) {
2318                 struct btrfs_file_extent_item *fi;
2319                 u64 extent_len;
2320                 struct btrfs_key found_key;
2321
2322                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2323                 if (ret < 0)
2324                         goto out_free_path;
2325
2326                 path->slots[0]--;
2327                 leaf = path->nodes[0];
2328                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2329
2330                 fi = btrfs_item_ptr(leaf, path->slots[0],
2331                                     struct btrfs_file_extent_item);
2332                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2333
2334                 if (extent_len + found_key.offset == start &&
2335                     relink_is_mergable(leaf, fi, new)) {
2336                         btrfs_set_file_extent_num_bytes(leaf, fi,
2337                                                         extent_len + len);
2338                         btrfs_mark_buffer_dirty(leaf);
2339                         inode_add_bytes(inode, len);
2340
2341                         ret = 1;
2342                         goto out_free_path;
2343                 } else {
2344                         merge = false;
2345                         btrfs_release_path(path);
2346                         goto again;
2347                 }
2348         }
2349
2350         ret = btrfs_insert_empty_item(trans, root, path, &key,
2351                                         sizeof(*extent));
2352         if (ret) {
2353                 btrfs_abort_transaction(trans, root, ret);
2354                 goto out_free_path;
2355         }
2356
2357         leaf = path->nodes[0];
2358         item = btrfs_item_ptr(leaf, path->slots[0],
2359                                 struct btrfs_file_extent_item);
2360         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2361         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2362         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2363         btrfs_set_file_extent_num_bytes(leaf, item, len);
2364         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2365         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2366         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2367         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2368         btrfs_set_file_extent_encryption(leaf, item, 0);
2369         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2370
2371         btrfs_mark_buffer_dirty(leaf);
2372         inode_add_bytes(inode, len);
2373         btrfs_release_path(path);
2374
2375         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2376                         new->disk_len, 0,
2377                         backref->root_id, backref->inum,
2378                         new->file_pos, 0);      /* start - extent_offset */
2379         if (ret) {
2380                 btrfs_abort_transaction(trans, root, ret);
2381                 goto out_free_path;
2382         }
2383
2384         ret = 1;
2385 out_free_path:
2386         btrfs_release_path(path);
2387         path->leave_spinning = 0;
2388         btrfs_end_transaction(trans, root);
2389 out_unlock:
2390         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2391                              &cached, GFP_NOFS);
2392         iput(inode);
2393         return ret;
2394 }
2395
2396 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2397 {
2398         struct old_sa_defrag_extent *old, *tmp;
2399
2400         if (!new)
2401                 return;
2402
2403         list_for_each_entry_safe(old, tmp, &new->head, list) {
2404                 list_del(&old->list);
2405                 kfree(old);
2406         }
2407         kfree(new);
2408 }
2409
2410 static void relink_file_extents(struct new_sa_defrag_extent *new)
2411 {
2412         struct btrfs_path *path;
2413         struct sa_defrag_extent_backref *backref;
2414         struct sa_defrag_extent_backref *prev = NULL;
2415         struct inode *inode;
2416         struct btrfs_root *root;
2417         struct rb_node *node;
2418         int ret;
2419
2420         inode = new->inode;
2421         root = BTRFS_I(inode)->root;
2422
2423         path = btrfs_alloc_path();
2424         if (!path)
2425                 return;
2426
2427         if (!record_extent_backrefs(path, new)) {
2428                 btrfs_free_path(path);
2429                 goto out;
2430         }
2431         btrfs_release_path(path);
2432
2433         while (1) {
2434                 node = rb_first(&new->root);
2435                 if (!node)
2436                         break;
2437                 rb_erase(node, &new->root);
2438
2439                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2440
2441                 ret = relink_extent_backref(path, prev, backref);
2442                 WARN_ON(ret < 0);
2443
2444                 kfree(prev);
2445
2446                 if (ret == 1)
2447                         prev = backref;
2448                 else
2449                         prev = NULL;
2450                 cond_resched();
2451         }
2452         kfree(prev);
2453
2454         btrfs_free_path(path);
2455 out:
2456         free_sa_defrag_extent(new);
2457
2458         atomic_dec(&root->fs_info->defrag_running);
2459         wake_up(&root->fs_info->transaction_wait);
2460 }
2461
2462 static struct new_sa_defrag_extent *
2463 record_old_file_extents(struct inode *inode,
2464                         struct btrfs_ordered_extent *ordered)
2465 {
2466         struct btrfs_root *root = BTRFS_I(inode)->root;
2467         struct btrfs_path *path;
2468         struct btrfs_key key;
2469         struct old_sa_defrag_extent *old;
2470         struct new_sa_defrag_extent *new;
2471         int ret;
2472
2473         new = kmalloc(sizeof(*new), GFP_NOFS);
2474         if (!new)
2475                 return NULL;
2476
2477         new->inode = inode;
2478         new->file_pos = ordered->file_offset;
2479         new->len = ordered->len;
2480         new->bytenr = ordered->start;
2481         new->disk_len = ordered->disk_len;
2482         new->compress_type = ordered->compress_type;
2483         new->root = RB_ROOT;
2484         INIT_LIST_HEAD(&new->head);
2485
2486         path = btrfs_alloc_path();
2487         if (!path)
2488                 goto out_kfree;
2489
2490         key.objectid = btrfs_ino(inode);
2491         key.type = BTRFS_EXTENT_DATA_KEY;
2492         key.offset = new->file_pos;
2493
2494         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2495         if (ret < 0)
2496                 goto out_free_path;
2497         if (ret > 0 && path->slots[0] > 0)
2498                 path->slots[0]--;
2499
2500         /* find out all the old extents for the file range */
2501         while (1) {
2502                 struct btrfs_file_extent_item *extent;
2503                 struct extent_buffer *l;
2504                 int slot;
2505                 u64 num_bytes;
2506                 u64 offset;
2507                 u64 end;
2508                 u64 disk_bytenr;
2509                 u64 extent_offset;
2510
2511                 l = path->nodes[0];
2512                 slot = path->slots[0];
2513
2514                 if (slot >= btrfs_header_nritems(l)) {
2515                         ret = btrfs_next_leaf(root, path);
2516                         if (ret < 0)
2517                                 goto out_free_path;
2518                         else if (ret > 0)
2519                                 break;
2520                         continue;
2521                 }
2522
2523                 btrfs_item_key_to_cpu(l, &key, slot);
2524
2525                 if (key.objectid != btrfs_ino(inode))
2526                         break;
2527                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2528                         break;
2529                 if (key.offset >= new->file_pos + new->len)
2530                         break;
2531
2532                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2533
2534                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2535                 if (key.offset + num_bytes < new->file_pos)
2536                         goto next;
2537
2538                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2539                 if (!disk_bytenr)
2540                         goto next;
2541
2542                 extent_offset = btrfs_file_extent_offset(l, extent);
2543
2544                 old = kmalloc(sizeof(*old), GFP_NOFS);
2545                 if (!old)
2546                         goto out_free_path;
2547
2548                 offset = max(new->file_pos, key.offset);
2549                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2550
2551                 old->bytenr = disk_bytenr;
2552                 old->extent_offset = extent_offset;
2553                 old->offset = offset - key.offset;
2554                 old->len = end - offset;
2555                 old->new = new;
2556                 old->count = 0;
2557                 list_add_tail(&old->list, &new->head);
2558 next:
2559                 path->slots[0]++;
2560                 cond_resched();
2561         }
2562
2563         btrfs_free_path(path);
2564         atomic_inc(&root->fs_info->defrag_running);
2565
2566         return new;
2567
2568 out_free_path:
2569         btrfs_free_path(path);
2570 out_kfree:
2571         free_sa_defrag_extent(new);
2572         return NULL;
2573 }
2574
2575 /* as ordered data IO finishes, this gets called so we can finish
2576  * an ordered extent if the range of bytes in the file it covers are
2577  * fully written.
2578  */
2579 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2580 {
2581         struct inode *inode = ordered_extent->inode;
2582         struct btrfs_root *root = BTRFS_I(inode)->root;
2583         struct btrfs_trans_handle *trans = NULL;
2584         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2585         struct extent_state *cached_state = NULL;
2586         struct new_sa_defrag_extent *new = NULL;
2587         int compress_type = 0;
2588         int ret = 0;
2589         u64 logical_len = ordered_extent->len;
2590         bool nolock;
2591         bool truncated = false;
2592
2593         nolock = btrfs_is_free_space_inode(inode);
2594
2595         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2596                 ret = -EIO;
2597                 goto out;
2598         }
2599
2600         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2601                 truncated = true;
2602                 logical_len = ordered_extent->truncated_len;
2603                 /* Truncated the entire extent, don't bother adding */
2604                 if (!logical_len)
2605                         goto out;
2606         }
2607
2608         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2609                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2610                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2611                 if (nolock)
2612                         trans = btrfs_join_transaction_nolock(root);
2613                 else
2614                         trans = btrfs_join_transaction(root);
2615                 if (IS_ERR(trans)) {
2616                         ret = PTR_ERR(trans);
2617                         trans = NULL;
2618                         goto out;
2619                 }
2620                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2621                 ret = btrfs_update_inode_fallback(trans, root, inode);
2622                 if (ret) /* -ENOMEM or corruption */
2623                         btrfs_abort_transaction(trans, root, ret);
2624                 goto out;
2625         }
2626
2627         lock_extent_bits(io_tree, ordered_extent->file_offset,
2628                          ordered_extent->file_offset + ordered_extent->len - 1,
2629                          0, &cached_state);
2630
2631         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2632                         ordered_extent->file_offset + ordered_extent->len - 1,
2633                         EXTENT_DEFRAG, 1, cached_state);
2634         if (ret) {
2635                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2636                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2637                         /* the inode is shared */
2638                         new = record_old_file_extents(inode, ordered_extent);
2639
2640                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2641                         ordered_extent->file_offset + ordered_extent->len - 1,
2642                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2643         }
2644
2645         if (nolock)
2646                 trans = btrfs_join_transaction_nolock(root);
2647         else
2648                 trans = btrfs_join_transaction(root);
2649         if (IS_ERR(trans)) {
2650                 ret = PTR_ERR(trans);
2651                 trans = NULL;
2652                 goto out_unlock;
2653         }
2654         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2655
2656         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2657                 compress_type = ordered_extent->compress_type;
2658         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2659                 BUG_ON(compress_type);
2660                 ret = btrfs_mark_extent_written(trans, inode,
2661                                                 ordered_extent->file_offset,
2662                                                 ordered_extent->file_offset +
2663                                                 logical_len);
2664         } else {
2665                 BUG_ON(root == root->fs_info->tree_root);
2666                 ret = insert_reserved_file_extent(trans, inode,
2667                                                 ordered_extent->file_offset,
2668                                                 ordered_extent->start,
2669                                                 ordered_extent->disk_len,
2670                                                 logical_len, logical_len,
2671                                                 compress_type, 0, 0,
2672                                                 BTRFS_FILE_EXTENT_REG);
2673         }
2674         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2675                            ordered_extent->file_offset, ordered_extent->len,
2676                            trans->transid);
2677         if (ret < 0) {
2678                 btrfs_abort_transaction(trans, root, ret);
2679                 goto out_unlock;
2680         }
2681
2682         add_pending_csums(trans, inode, ordered_extent->file_offset,
2683                           &ordered_extent->list);
2684
2685         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2686         ret = btrfs_update_inode_fallback(trans, root, inode);
2687         if (ret) { /* -ENOMEM or corruption */
2688                 btrfs_abort_transaction(trans, root, ret);
2689                 goto out_unlock;
2690         }
2691         ret = 0;
2692 out_unlock:
2693         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2694                              ordered_extent->file_offset +
2695                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2696 out:
2697         if (root != root->fs_info->tree_root)
2698                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2699         if (trans)
2700                 btrfs_end_transaction(trans, root);
2701
2702         if (ret || truncated) {
2703                 u64 start, end;
2704
2705                 if (truncated)
2706                         start = ordered_extent->file_offset + logical_len;
2707                 else
2708                         start = ordered_extent->file_offset;
2709                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2710                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2711
2712                 /* Drop the cache for the part of the extent we didn't write. */
2713                 btrfs_drop_extent_cache(inode, start, end, 0);
2714
2715                 /*
2716                  * If the ordered extent had an IOERR or something else went
2717                  * wrong we need to return the space for this ordered extent
2718                  * back to the allocator.  We only free the extent in the
2719                  * truncated case if we didn't write out the extent at all.
2720                  */
2721                 if ((ret || !logical_len) &&
2722                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2723                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2724                         btrfs_free_reserved_extent(root, ordered_extent->start,
2725                                                    ordered_extent->disk_len);
2726         }
2727
2728
2729         /*
2730          * This needs to be done to make sure anybody waiting knows we are done
2731          * updating everything for this ordered extent.
2732          */
2733         btrfs_remove_ordered_extent(inode, ordered_extent);
2734
2735         /* for snapshot-aware defrag */
2736         if (new) {
2737                 if (ret) {
2738                         free_sa_defrag_extent(new);
2739                         atomic_dec(&root->fs_info->defrag_running);
2740                 } else {
2741                         relink_file_extents(new);
2742                 }
2743         }
2744
2745         /* once for us */
2746         btrfs_put_ordered_extent(ordered_extent);
2747         /* once for the tree */
2748         btrfs_put_ordered_extent(ordered_extent);
2749
2750         return ret;
2751 }
2752
2753 static void finish_ordered_fn(struct btrfs_work *work)
2754 {
2755         struct btrfs_ordered_extent *ordered_extent;
2756         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2757         btrfs_finish_ordered_io(ordered_extent);
2758 }
2759
2760 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2761                                 struct extent_state *state, int uptodate)
2762 {
2763         struct inode *inode = page->mapping->host;
2764         struct btrfs_root *root = BTRFS_I(inode)->root;
2765         struct btrfs_ordered_extent *ordered_extent = NULL;
2766         struct btrfs_workqueue *workers;
2767
2768         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2769
2770         ClearPagePrivate2(page);
2771         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2772                                             end - start + 1, uptodate))
2773                 return 0;
2774
2775         btrfs_init_work(&ordered_extent->work, finish_ordered_fn, NULL, NULL);
2776
2777         if (btrfs_is_free_space_inode(inode))
2778                 workers = root->fs_info->endio_freespace_worker;
2779         else
2780                 workers = root->fs_info->endio_write_workers;
2781         btrfs_queue_work(workers, &ordered_extent->work);
2782
2783         return 0;
2784 }
2785
2786 /*
2787  * when reads are done, we need to check csums to verify the data is correct
2788  * if there's a match, we allow the bio to finish.  If not, the code in
2789  * extent_io.c will try to find good copies for us.
2790  */
2791 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2792                                       u64 phy_offset, struct page *page,
2793                                       u64 start, u64 end, int mirror)
2794 {
2795         size_t offset = start - page_offset(page);
2796         struct inode *inode = page->mapping->host;
2797         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2798         char *kaddr;
2799         struct btrfs_root *root = BTRFS_I(inode)->root;
2800         u32 csum_expected;
2801         u32 csum = ~(u32)0;
2802         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
2803                                       DEFAULT_RATELIMIT_BURST);
2804
2805         if (PageChecked(page)) {
2806                 ClearPageChecked(page);
2807                 goto good;
2808         }
2809
2810         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2811                 goto good;
2812
2813         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2814             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2815                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2816                                   GFP_NOFS);
2817                 return 0;
2818         }
2819
2820         phy_offset >>= inode->i_sb->s_blocksize_bits;
2821         csum_expected = *(((u32 *)io_bio->csum) + phy_offset);
2822
2823         kaddr = kmap_atomic(page);
2824         csum = btrfs_csum_data(kaddr + offset, csum,  end - start + 1);
2825         btrfs_csum_final(csum, (char *)&csum);
2826         if (csum != csum_expected)
2827                 goto zeroit;
2828
2829         kunmap_atomic(kaddr);
2830 good:
2831         return 0;
2832
2833 zeroit:
2834         if (__ratelimit(&_rs))
2835                 btrfs_info(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
2836                         btrfs_ino(page->mapping->host), start, csum, csum_expected);
2837         memset(kaddr + offset, 1, end - start + 1);
2838         flush_dcache_page(page);
2839         kunmap_atomic(kaddr);
2840         if (csum_expected == 0)
2841                 return 0;
2842         return -EIO;
2843 }
2844
2845 struct delayed_iput {
2846         struct list_head list;
2847         struct inode *inode;
2848 };
2849
2850 /* JDM: If this is fs-wide, why can't we add a pointer to
2851  * btrfs_inode instead and avoid the allocation? */
2852 void btrfs_add_delayed_iput(struct inode *inode)
2853 {
2854         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2855         struct delayed_iput *delayed;
2856
2857         if (atomic_add_unless(&inode->i_count, -1, 1))
2858                 return;
2859
2860         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2861         delayed->inode = inode;
2862
2863         spin_lock(&fs_info->delayed_iput_lock);
2864         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2865         spin_unlock(&fs_info->delayed_iput_lock);
2866 }
2867
2868 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2869 {
2870         LIST_HEAD(list);
2871         struct btrfs_fs_info *fs_info = root->fs_info;
2872         struct delayed_iput *delayed;
2873         int empty;
2874
2875         spin_lock(&fs_info->delayed_iput_lock);
2876         empty = list_empty(&fs_info->delayed_iputs);
2877         spin_unlock(&fs_info->delayed_iput_lock);
2878         if (empty)
2879                 return;
2880
2881         spin_lock(&fs_info->delayed_iput_lock);
2882         list_splice_init(&fs_info->delayed_iputs, &list);
2883         spin_unlock(&fs_info->delayed_iput_lock);
2884
2885         while (!list_empty(&list)) {
2886                 delayed = list_entry(list.next, struct delayed_iput, list);
2887                 list_del(&delayed->list);
2888                 iput(delayed->inode);
2889                 kfree(delayed);
2890         }
2891 }
2892
2893 /*
2894  * This is called in transaction commit time. If there are no orphan
2895  * files in the subvolume, it removes orphan item and frees block_rsv
2896  * structure.
2897  */
2898 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2899                               struct btrfs_root *root)
2900 {
2901         struct btrfs_block_rsv *block_rsv;
2902         int ret;
2903
2904         if (atomic_read(&root->orphan_inodes) ||
2905             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2906                 return;
2907
2908         spin_lock(&root->orphan_lock);
2909         if (atomic_read(&root->orphan_inodes)) {
2910                 spin_unlock(&root->orphan_lock);
2911                 return;
2912         }
2913
2914         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
2915                 spin_unlock(&root->orphan_lock);
2916                 return;
2917         }
2918
2919         block_rsv = root->orphan_block_rsv;
2920         root->orphan_block_rsv = NULL;
2921         spin_unlock(&root->orphan_lock);
2922
2923         if (root->orphan_item_inserted &&
2924             btrfs_root_refs(&root->root_item) > 0) {
2925                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2926                                             root->root_key.objectid);
2927                 if (ret)
2928                         btrfs_abort_transaction(trans, root, ret);
2929                 else
2930                         root->orphan_item_inserted = 0;
2931         }
2932
2933         if (block_rsv) {
2934                 WARN_ON(block_rsv->size > 0);
2935                 btrfs_free_block_rsv(root, block_rsv);
2936         }
2937 }
2938
2939 /*
2940  * This creates an orphan entry for the given inode in case something goes
2941  * wrong in the middle of an unlink/truncate.
2942  *
2943  * NOTE: caller of this function should reserve 5 units of metadata for
2944  *       this function.
2945  */
2946 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2947 {
2948         struct btrfs_root *root = BTRFS_I(inode)->root;
2949         struct btrfs_block_rsv *block_rsv = NULL;
2950         int reserve = 0;
2951         int insert = 0;
2952         int ret;
2953
2954         if (!root->orphan_block_rsv) {
2955                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2956                 if (!block_rsv)
2957                         return -ENOMEM;
2958         }
2959
2960         spin_lock(&root->orphan_lock);
2961         if (!root->orphan_block_rsv) {
2962                 root->orphan_block_rsv = block_rsv;
2963         } else if (block_rsv) {
2964                 btrfs_free_block_rsv(root, block_rsv);
2965                 block_rsv = NULL;
2966         }
2967
2968         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
2969                               &BTRFS_I(inode)->runtime_flags)) {
2970 #if 0
2971                 /*
2972                  * For proper ENOSPC handling, we should do orphan
2973                  * cleanup when mounting. But this introduces backward
2974                  * compatibility issue.
2975                  */
2976                 if (!xchg(&root->orphan_item_inserted, 1))
2977                         insert = 2;
2978                 else
2979                         insert = 1;
2980 #endif
2981                 insert = 1;
2982                 atomic_inc(&root->orphan_inodes);
2983         }
2984
2985         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
2986                               &BTRFS_I(inode)->runtime_flags))
2987                 reserve = 1;
2988         spin_unlock(&root->orphan_lock);
2989
2990         /* grab metadata reservation from transaction handle */
2991         if (reserve) {
2992                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2993                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
2994         }
2995
2996         /* insert an orphan item to track this unlinked/truncated file */
2997         if (insert >= 1) {
2998                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
2999                 if (ret) {
3000                         atomic_dec(&root->orphan_inodes);
3001                         if (reserve) {
3002                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3003                                           &BTRFS_I(inode)->runtime_flags);
3004                                 btrfs_orphan_release_metadata(inode);
3005                         }
3006                         if (ret != -EEXIST) {
3007                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3008                                           &BTRFS_I(inode)->runtime_flags);
3009                                 btrfs_abort_transaction(trans, root, ret);
3010                                 return ret;
3011                         }
3012                 }
3013                 ret = 0;
3014         }
3015
3016         /* insert an orphan item to track subvolume contains orphan files */
3017         if (insert >= 2) {
3018                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3019                                                root->root_key.objectid);
3020                 if (ret && ret != -EEXIST) {
3021                         btrfs_abort_transaction(trans, root, ret);
3022                         return ret;
3023                 }
3024         }
3025         return 0;
3026 }
3027
3028 /*
3029  * We have done the truncate/delete so we can go ahead and remove the orphan
3030  * item for this particular inode.
3031  */
3032 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3033                             struct inode *inode)
3034 {
3035         struct btrfs_root *root = BTRFS_I(inode)->root;
3036         int delete_item = 0;
3037         int release_rsv = 0;
3038         int ret = 0;
3039
3040         spin_lock(&root->orphan_lock);
3041         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3042                                &BTRFS_I(inode)->runtime_flags))
3043                 delete_item = 1;
3044
3045         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3046                                &BTRFS_I(inode)->runtime_flags))
3047                 release_rsv = 1;
3048         spin_unlock(&root->orphan_lock);
3049
3050         if (delete_item) {
3051                 atomic_dec(&root->orphan_inodes);
3052                 if (trans)
3053                         ret = btrfs_del_orphan_item(trans, root,
3054                                                     btrfs_ino(inode));
3055         }
3056
3057         if (release_rsv)
3058                 btrfs_orphan_release_metadata(inode);
3059
3060         return ret;
3061 }
3062
3063 /*
3064  * this cleans up any orphans that may be left on the list from the last use
3065  * of this root.
3066  */
3067 int btrfs_orphan_cleanup(struct btrfs_root *root)
3068 {
3069         struct btrfs_path *path;
3070         struct extent_buffer *leaf;
3071         struct btrfs_key key, found_key;
3072         struct btrfs_trans_handle *trans;
3073         struct inode *inode;
3074         u64 last_objectid = 0;
3075         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3076
3077         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3078                 return 0;
3079
3080         path = btrfs_alloc_path();
3081         if (!path) {
3082                 ret = -ENOMEM;
3083                 goto out;
3084         }
3085         path->reada = -1;
3086
3087         key.objectid = BTRFS_ORPHAN_OBJECTID;
3088         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
3089         key.offset = (u64)-1;
3090
3091         while (1) {
3092                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3093                 if (ret < 0)
3094                         goto out;
3095
3096                 /*
3097                  * if ret == 0 means we found what we were searching for, which
3098                  * is weird, but possible, so only screw with path if we didn't
3099                  * find the key and see if we have stuff that matches
3100                  */
3101                 if (ret > 0) {
3102                         ret = 0;
3103                         if (path->slots[0] == 0)
3104                                 break;
3105                         path->slots[0]--;
3106                 }
3107
3108                 /* pull out the item */
3109                 leaf = path->nodes[0];
3110                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3111
3112                 /* make sure the item matches what we want */
3113                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3114                         break;
3115                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
3116                         break;
3117
3118                 /* release the path since we're done with it */
3119                 btrfs_release_path(path);
3120
3121                 /*
3122                  * this is where we are basically btrfs_lookup, without the
3123                  * crossing root thing.  we store the inode number in the
3124                  * offset of the orphan item.
3125                  */
3126
3127                 if (found_key.offset == last_objectid) {
3128                         btrfs_err(root->fs_info,
3129                                 "Error removing orphan entry, stopping orphan cleanup");
3130                         ret = -EINVAL;
3131                         goto out;
3132                 }
3133
3134                 last_objectid = found_key.offset;
3135
3136                 found_key.objectid = found_key.offset;
3137                 found_key.type = BTRFS_INODE_ITEM_KEY;
3138                 found_key.offset = 0;
3139                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3140                 ret = PTR_ERR_OR_ZERO(inode);
3141                 if (ret && ret != -ESTALE)
3142                         goto out;
3143
3144                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3145                         struct btrfs_root *dead_root;
3146                         struct btrfs_fs_info *fs_info = root->fs_info;
3147                         int is_dead_root = 0;
3148
3149                         /*
3150                          * this is an orphan in the tree root. Currently these
3151                          * could come from 2 sources:
3152                          *  a) a snapshot deletion in progress
3153                          *  b) a free space cache inode
3154                          * We need to distinguish those two, as the snapshot
3155                          * orphan must not get deleted.
3156                          * find_dead_roots already ran before us, so if this
3157                          * is a snapshot deletion, we should find the root
3158                          * in the dead_roots list
3159                          */
3160                         spin_lock(&fs_info->trans_lock);
3161                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3162                                             root_list) {
3163                                 if (dead_root->root_key.objectid ==
3164                                     found_key.objectid) {
3165                                         is_dead_root = 1;
3166                                         break;
3167                                 }
3168                         }
3169                         spin_unlock(&fs_info->trans_lock);
3170                         if (is_dead_root) {
3171                                 /* prevent this orphan from being found again */
3172                                 key.offset = found_key.objectid - 1;
3173                                 continue;
3174                         }
3175                 }
3176                 /*
3177                  * Inode is already gone but the orphan item is still there,
3178                  * kill the orphan item.
3179                  */
3180                 if (ret == -ESTALE) {
3181                         trans = btrfs_start_transaction(root, 1);
3182                         if (IS_ERR(trans)) {
3183                                 ret = PTR_ERR(trans);
3184                                 goto out;
3185                         }
3186                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3187                                 found_key.objectid);
3188                         ret = btrfs_del_orphan_item(trans, root,
3189                                                     found_key.objectid);
3190                         btrfs_end_transaction(trans, root);
3191                         if (ret)
3192                                 goto out;
3193                         continue;
3194                 }
3195
3196                 /*
3197                  * add this inode to the orphan list so btrfs_orphan_del does
3198                  * the proper thing when we hit it
3199                  */
3200                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3201                         &BTRFS_I(inode)->runtime_flags);
3202                 atomic_inc(&root->orphan_inodes);
3203
3204                 /* if we have links, this was a truncate, lets do that */
3205                 if (inode->i_nlink) {
3206                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3207                                 iput(inode);
3208                                 continue;
3209                         }
3210                         nr_truncate++;
3211
3212                         /* 1 for the orphan item deletion. */
3213                         trans = btrfs_start_transaction(root, 1);
3214                         if (IS_ERR(trans)) {
3215                                 iput(inode);
3216                                 ret = PTR_ERR(trans);
3217                                 goto out;
3218                         }
3219                         ret = btrfs_orphan_add(trans, inode);
3220                         btrfs_end_transaction(trans, root);
3221                         if (ret) {
3222                                 iput(inode);
3223                                 goto out;
3224                         }
3225
3226                         ret = btrfs_truncate(inode);
3227                         if (ret)
3228                                 btrfs_orphan_del(NULL, inode);
3229                 } else {
3230                         nr_unlink++;
3231                 }
3232
3233                 /* this will do delete_inode and everything for us */
3234                 iput(inode);
3235                 if (ret)
3236                         goto out;
3237         }
3238         /* release the path since we're done with it */
3239         btrfs_release_path(path);
3240
3241         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3242
3243         if (root->orphan_block_rsv)
3244                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3245                                         (u64)-1);
3246
3247         if (root->orphan_block_rsv || root->orphan_item_inserted) {
3248                 trans = btrfs_join_transaction(root);
3249                 if (!IS_ERR(trans))
3250                         btrfs_end_transaction(trans, root);
3251         }
3252
3253         if (nr_unlink)
3254                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3255         if (nr_truncate)
3256                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3257
3258 out:
3259         if (ret)
3260                 btrfs_crit(root->fs_info,
3261                         "could not do orphan cleanup %d", ret);
3262         btrfs_free_path(path);
3263         return ret;
3264 }
3265
3266 /*
3267  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3268  * don't find any xattrs, we know there can't be any acls.
3269  *
3270  * slot is the slot the inode is in, objectid is the objectid of the inode
3271  */
3272 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3273                                           int slot, u64 objectid,
3274                                           int *first_xattr_slot)
3275 {
3276         u32 nritems = btrfs_header_nritems(leaf);
3277         struct btrfs_key found_key;
3278         static u64 xattr_access = 0;
3279         static u64 xattr_default = 0;
3280         int scanned = 0;
3281
3282         if (!xattr_access) {
3283                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3284                                         strlen(POSIX_ACL_XATTR_ACCESS));
3285                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3286                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3287         }
3288
3289         slot++;
3290         *first_xattr_slot = -1;
3291         while (slot < nritems) {
3292                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3293
3294                 /* we found a different objectid, there must not be acls */
3295                 if (found_key.objectid != objectid)
3296                         return 0;
3297
3298                 /* we found an xattr, assume we've got an acl */
3299                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3300                         if (*first_xattr_slot == -1)
3301                                 *first_xattr_slot = slot;
3302                         if (found_key.offset == xattr_access ||
3303                             found_key.offset == xattr_default)
3304                                 return 1;
3305                 }
3306
3307                 /*
3308                  * we found a key greater than an xattr key, there can't
3309                  * be any acls later on
3310                  */
3311                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3312                         return 0;
3313
3314                 slot++;
3315                 scanned++;
3316
3317                 /*
3318                  * it goes inode, inode backrefs, xattrs, extents,
3319                  * so if there are a ton of hard links to an inode there can
3320                  * be a lot of backrefs.  Don't waste time searching too hard,
3321                  * this is just an optimization
3322                  */
3323                 if (scanned >= 8)
3324                         break;
3325         }
3326         /* we hit the end of the leaf before we found an xattr or
3327          * something larger than an xattr.  We have to assume the inode
3328          * has acls
3329          */
3330         if (*first_xattr_slot == -1)
3331                 *first_xattr_slot = slot;
3332         return 1;
3333 }
3334
3335 /*
3336  * read an inode from the btree into the in-memory inode
3337  */
3338 static void btrfs_read_locked_inode(struct inode *inode)
3339 {
3340         struct btrfs_path *path;
3341         struct extent_buffer *leaf;
3342         struct btrfs_inode_item *inode_item;
3343         struct btrfs_timespec *tspec;
3344         struct btrfs_root *root = BTRFS_I(inode)->root;
3345         struct btrfs_key location;
3346         unsigned long ptr;
3347         int maybe_acls;
3348         u32 rdev;
3349         int ret;
3350         bool filled = false;
3351         int first_xattr_slot;
3352
3353         ret = btrfs_fill_inode(inode, &rdev);
3354         if (!ret)
3355                 filled = true;
3356
3357         path = btrfs_alloc_path();
3358         if (!path)
3359                 goto make_bad;
3360
3361         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3362
3363         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3364         if (ret)
3365                 goto make_bad;
3366
3367         leaf = path->nodes[0];
3368
3369         if (filled)
3370                 goto cache_index;
3371
3372         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3373                                     struct btrfs_inode_item);
3374         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3375         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3376         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3377         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3378         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3379
3380         tspec = btrfs_inode_atime(inode_item);
3381         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3382         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3383
3384         tspec = btrfs_inode_mtime(inode_item);
3385         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3386         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3387
3388         tspec = btrfs_inode_ctime(inode_item);
3389         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3390         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3391
3392         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3393         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3394         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3395
3396         /*
3397          * If we were modified in the current generation and evicted from memory
3398          * and then re-read we need to do a full sync since we don't have any
3399          * idea about which extents were modified before we were evicted from
3400          * cache.
3401          */
3402         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3403                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3404                         &BTRFS_I(inode)->runtime_flags);
3405
3406         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3407         inode->i_generation = BTRFS_I(inode)->generation;
3408         inode->i_rdev = 0;
3409         rdev = btrfs_inode_rdev(leaf, inode_item);
3410
3411         BTRFS_I(inode)->index_cnt = (u64)-1;
3412         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3413
3414 cache_index:
3415         path->slots[0]++;
3416         if (inode->i_nlink != 1 ||
3417             path->slots[0] >= btrfs_header_nritems(leaf))
3418                 goto cache_acl;
3419
3420         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3421         if (location.objectid != btrfs_ino(inode))
3422                 goto cache_acl;
3423
3424         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3425         if (location.type == BTRFS_INODE_REF_KEY) {
3426                 struct btrfs_inode_ref *ref;
3427
3428                 ref = (struct btrfs_inode_ref *)ptr;
3429                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3430         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3431                 struct btrfs_inode_extref *extref;
3432
3433                 extref = (struct btrfs_inode_extref *)ptr;
3434                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3435                                                                      extref);
3436         }
3437 cache_acl:
3438         /*
3439          * try to precache a NULL acl entry for files that don't have
3440          * any xattrs or acls
3441          */
3442         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3443                                            btrfs_ino(inode), &first_xattr_slot);
3444         if (first_xattr_slot != -1) {
3445                 path->slots[0] = first_xattr_slot;
3446                 ret = btrfs_load_inode_props(inode, path);
3447                 if (ret)
3448                         btrfs_err(root->fs_info,
3449                                   "error loading props for ino %llu (root %llu): %d\n",
3450                                   btrfs_ino(inode),
3451                                   root->root_key.objectid, ret);
3452         }
3453         btrfs_free_path(path);
3454
3455         if (!maybe_acls)
3456                 cache_no_acl(inode);
3457
3458         switch (inode->i_mode & S_IFMT) {
3459         case S_IFREG:
3460                 inode->i_mapping->a_ops = &btrfs_aops;
3461                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3462                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3463                 inode->i_fop = &btrfs_file_operations;
3464                 inode->i_op = &btrfs_file_inode_operations;
3465                 break;
3466         case S_IFDIR:
3467                 inode->i_fop = &btrfs_dir_file_operations;
3468                 if (root == root->fs_info->tree_root)
3469                         inode->i_op = &btrfs_dir_ro_inode_operations;
3470                 else
3471                         inode->i_op = &btrfs_dir_inode_operations;
3472                 break;
3473         case S_IFLNK:
3474                 inode->i_op = &btrfs_symlink_inode_operations;
3475                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3476                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3477                 break;
3478         default:
3479                 inode->i_op = &btrfs_special_inode_operations;
3480                 init_special_inode(inode, inode->i_mode, rdev);
3481                 break;
3482         }
3483
3484         btrfs_update_iflags(inode);
3485         return;
3486
3487 make_bad:
3488         btrfs_free_path(path);
3489         make_bad_inode(inode);
3490 }
3491
3492 /*
3493  * given a leaf and an inode, copy the inode fields into the leaf
3494  */
3495 static void fill_inode_item(struct btrfs_trans_handle *trans,
3496                             struct extent_buffer *leaf,
3497                             struct btrfs_inode_item *item,
3498                             struct inode *inode)
3499 {
3500         struct btrfs_map_token token;
3501
3502         btrfs_init_map_token(&token);
3503
3504         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3505         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3506         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3507                                    &token);
3508         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3509         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3510
3511         btrfs_set_token_timespec_sec(leaf, btrfs_inode_atime(item),
3512                                      inode->i_atime.tv_sec, &token);
3513         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_atime(item),
3514                                       inode->i_atime.tv_nsec, &token);
3515
3516         btrfs_set_token_timespec_sec(leaf, btrfs_inode_mtime(item),
3517                                      inode->i_mtime.tv_sec, &token);
3518         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_mtime(item),
3519                                       inode->i_mtime.tv_nsec, &token);
3520
3521         btrfs_set_token_timespec_sec(leaf, btrfs_inode_ctime(item),
3522                                      inode->i_ctime.tv_sec, &token);
3523         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_ctime(item),
3524                                       inode->i_ctime.tv_nsec, &token);
3525
3526         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3527                                      &token);
3528         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3529                                          &token);
3530         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3531         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3532         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3533         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3534         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3535 }
3536
3537 /*
3538  * copy everything in the in-memory inode into the btree.
3539  */
3540 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3541                                 struct btrfs_root *root, struct inode *inode)
3542 {
3543         struct btrfs_inode_item *inode_item;
3544         struct btrfs_path *path;
3545         struct extent_buffer *leaf;
3546         int ret;
3547
3548         path = btrfs_alloc_path();
3549         if (!path)
3550                 return -ENOMEM;
3551
3552         path->leave_spinning = 1;
3553         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3554                                  1);
3555         if (ret) {
3556                 if (ret > 0)
3557                         ret = -ENOENT;
3558                 goto failed;
3559         }
3560
3561         leaf = path->nodes[0];
3562         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3563                                     struct btrfs_inode_item);
3564
3565         fill_inode_item(trans, leaf, inode_item, inode);
3566         btrfs_mark_buffer_dirty(leaf);
3567         btrfs_set_inode_last_trans(trans, inode);
3568         ret = 0;
3569 failed:
3570         btrfs_free_path(path);
3571         return ret;
3572 }
3573
3574 /*
3575  * copy everything in the in-memory inode into the btree.
3576  */
3577 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3578                                 struct btrfs_root *root, struct inode *inode)
3579 {
3580         int ret;
3581
3582         /*
3583          * If the inode is a free space inode, we can deadlock during commit
3584          * if we put it into the delayed code.
3585          *
3586          * The data relocation inode should also be directly updated
3587          * without delay
3588          */
3589         if (!btrfs_is_free_space_inode(inode)
3590             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
3591                 btrfs_update_root_times(trans, root);
3592
3593                 ret = btrfs_delayed_update_inode(trans, root, inode);
3594                 if (!ret)
3595                         btrfs_set_inode_last_trans(trans, inode);
3596                 return ret;
3597         }
3598
3599         return btrfs_update_inode_item(trans, root, inode);
3600 }
3601
3602 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3603                                          struct btrfs_root *root,
3604                                          struct inode *inode)
3605 {
3606         int ret;
3607
3608         ret = btrfs_update_inode(trans, root, inode);
3609         if (ret == -ENOSPC)
3610                 return btrfs_update_inode_item(trans, root, inode);
3611         return ret;
3612 }
3613
3614 /*
3615  * unlink helper that gets used here in inode.c and in the tree logging
3616  * recovery code.  It remove a link in a directory with a given name, and
3617  * also drops the back refs in the inode to the directory
3618  */
3619 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3620                                 struct btrfs_root *root,
3621                                 struct inode *dir, struct inode *inode,
3622                                 const char *name, int name_len)
3623 {
3624         struct btrfs_path *path;
3625         int ret = 0;
3626         struct extent_buffer *leaf;
3627         struct btrfs_dir_item *di;
3628         struct btrfs_key key;
3629         u64 index;
3630         u64 ino = btrfs_ino(inode);
3631         u64 dir_ino = btrfs_ino(dir);
3632
3633         path = btrfs_alloc_path();
3634         if (!path) {
3635                 ret = -ENOMEM;
3636                 goto out;
3637         }
3638
3639         path->leave_spinning = 1;
3640         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3641                                     name, name_len, -1);
3642         if (IS_ERR(di)) {
3643                 ret = PTR_ERR(di);
3644                 goto err;
3645         }
3646         if (!di) {
3647                 ret = -ENOENT;
3648                 goto err;
3649         }
3650         leaf = path->nodes[0];
3651         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3652         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3653         if (ret)
3654                 goto err;
3655         btrfs_release_path(path);
3656
3657         /*
3658          * If we don't have dir index, we have to get it by looking up
3659          * the inode ref, since we get the inode ref, remove it directly,
3660          * it is unnecessary to do delayed deletion.
3661          *
3662          * But if we have dir index, needn't search inode ref to get it.
3663          * Since the inode ref is close to the inode item, it is better
3664          * that we delay to delete it, and just do this deletion when
3665          * we update the inode item.
3666          */
3667         if (BTRFS_I(inode)->dir_index) {
3668                 ret = btrfs_delayed_delete_inode_ref(inode);
3669                 if (!ret) {
3670                         index = BTRFS_I(inode)->dir_index;
3671                         goto skip_backref;
3672                 }
3673         }
3674
3675         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3676                                   dir_ino, &index);
3677         if (ret) {
3678                 btrfs_info(root->fs_info,
3679                         "failed to delete reference to %.*s, inode %llu parent %llu",
3680                         name_len, name, ino, dir_ino);
3681                 btrfs_abort_transaction(trans, root, ret);
3682                 goto err;
3683         }
3684 skip_backref:
3685         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3686         if (ret) {
3687                 btrfs_abort_transaction(trans, root, ret);
3688                 goto err;
3689         }
3690
3691         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3692                                          inode, dir_ino);
3693         if (ret != 0 && ret != -ENOENT) {
3694                 btrfs_abort_transaction(trans, root, ret);
3695                 goto err;
3696         }
3697
3698         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
3699                                            dir, index);
3700         if (ret == -ENOENT)
3701                 ret = 0;
3702         else if (ret)
3703                 btrfs_abort_transaction(trans, root, ret);
3704 err:
3705         btrfs_free_path(path);
3706         if (ret)
3707                 goto out;
3708
3709         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3710         inode_inc_iversion(inode);
3711         inode_inc_iversion(dir);
3712         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3713         ret = btrfs_update_inode(trans, root, dir);
3714 out:
3715         return ret;
3716 }
3717
3718 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3719                        struct btrfs_root *root,
3720                        struct inode *dir, struct inode *inode,
3721                        const char *name, int name_len)
3722 {
3723         int ret;
3724         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3725         if (!ret) {
3726                 drop_nlink(inode);
3727                 ret = btrfs_update_inode(trans, root, inode);
3728         }
3729         return ret;
3730 }
3731
3732 /*
3733  * helper to start transaction for unlink and rmdir.
3734  *
3735  * unlink and rmdir are special in btrfs, they do not always free space, so
3736  * if we cannot make our reservations the normal way try and see if there is
3737  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3738  * allow the unlink to occur.
3739  */
3740 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3741 {
3742         struct btrfs_trans_handle *trans;
3743         struct btrfs_root *root = BTRFS_I(dir)->root;
3744         int ret;
3745
3746         /*
3747          * 1 for the possible orphan item
3748          * 1 for the dir item
3749          * 1 for the dir index
3750          * 1 for the inode ref
3751          * 1 for the inode
3752          */
3753         trans = btrfs_start_transaction(root, 5);
3754         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
3755                 return trans;
3756
3757         if (PTR_ERR(trans) == -ENOSPC) {
3758                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3759
3760                 trans = btrfs_start_transaction(root, 0);
3761                 if (IS_ERR(trans))
3762                         return trans;
3763                 ret = btrfs_cond_migrate_bytes(root->fs_info,
3764                                                &root->fs_info->trans_block_rsv,
3765                                                num_bytes, 5);
3766                 if (ret) {
3767                         btrfs_end_transaction(trans, root);
3768                         return ERR_PTR(ret);
3769                 }
3770                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3771                 trans->bytes_reserved = num_bytes;
3772         }
3773         return trans;
3774 }
3775
3776 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3777 {
3778         struct btrfs_root *root = BTRFS_I(dir)->root;
3779         struct btrfs_trans_handle *trans;
3780         struct inode *inode = dentry->d_inode;
3781         int ret;
3782
3783         trans = __unlink_start_trans(dir);
3784         if (IS_ERR(trans))
3785                 return PTR_ERR(trans);
3786
3787         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3788
3789         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3790                                  dentry->d_name.name, dentry->d_name.len);
3791         if (ret)
3792                 goto out;
3793
3794         if (inode->i_nlink == 0) {
3795                 ret = btrfs_orphan_add(trans, inode);
3796                 if (ret)
3797                         goto out;
3798         }
3799
3800 out:
3801         btrfs_end_transaction(trans, root);
3802         btrfs_btree_balance_dirty(root);
3803         return ret;
3804 }
3805
3806 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3807                         struct btrfs_root *root,
3808                         struct inode *dir, u64 objectid,
3809                         const char *name, int name_len)
3810 {
3811         struct btrfs_path *path;
3812         struct extent_buffer *leaf;
3813         struct btrfs_dir_item *di;
3814         struct btrfs_key key;
3815         u64 index;
3816         int ret;
3817         u64 dir_ino = btrfs_ino(dir);
3818
3819         path = btrfs_alloc_path();
3820         if (!path)
3821                 return -ENOMEM;
3822
3823         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3824                                    name, name_len, -1);
3825         if (IS_ERR_OR_NULL(di)) {
3826                 if (!di)
3827                         ret = -ENOENT;
3828                 else
3829                         ret = PTR_ERR(di);
3830                 goto out;
3831         }
3832
3833         leaf = path->nodes[0];
3834         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3835         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3836         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3837         if (ret) {
3838                 btrfs_abort_transaction(trans, root, ret);
3839                 goto out;
3840         }
3841         btrfs_release_path(path);
3842
3843         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3844                                  objectid, root->root_key.objectid,
3845                                  dir_ino, &index, name, name_len);
3846         if (ret < 0) {
3847                 if (ret != -ENOENT) {
3848                         btrfs_abort_transaction(trans, root, ret);
3849                         goto out;
3850                 }
3851                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3852                                                  name, name_len);
3853                 if (IS_ERR_OR_NULL(di)) {
3854                         if (!di)
3855                                 ret = -ENOENT;
3856                         else
3857                                 ret = PTR_ERR(di);
3858                         btrfs_abort_transaction(trans, root, ret);
3859                         goto out;
3860                 }
3861
3862                 leaf = path->nodes[0];
3863                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3864                 btrfs_release_path(path);
3865                 index = key.offset;
3866         }
3867         btrfs_release_path(path);
3868
3869         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3870         if (ret) {
3871                 btrfs_abort_transaction(trans, root, ret);
3872                 goto out;
3873         }
3874
3875         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3876         inode_inc_iversion(dir);
3877         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3878         ret = btrfs_update_inode_fallback(trans, root, dir);
3879         if (ret)
3880                 btrfs_abort_transaction(trans, root, ret);
3881 out:
3882         btrfs_free_path(path);
3883         return ret;
3884 }
3885
3886 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3887 {
3888         struct inode *inode = dentry->d_inode;
3889         int err = 0;
3890         struct btrfs_root *root = BTRFS_I(dir)->root;
3891         struct btrfs_trans_handle *trans;
3892
3893         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
3894                 return -ENOTEMPTY;
3895         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3896                 return -EPERM;
3897
3898         trans = __unlink_start_trans(dir);
3899         if (IS_ERR(trans))
3900                 return PTR_ERR(trans);
3901
3902         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3903                 err = btrfs_unlink_subvol(trans, root, dir,
3904                                           BTRFS_I(inode)->location.objectid,
3905                                           dentry->d_name.name,
3906                                           dentry->d_name.len);
3907                 goto out;
3908         }
3909
3910         err = btrfs_orphan_add(trans, inode);
3911         if (err)
3912                 goto out;
3913
3914         /* now the directory is empty */
3915         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3916                                  dentry->d_name.name, dentry->d_name.len);
3917         if (!err)
3918                 btrfs_i_size_write(inode, 0);
3919 out:
3920         btrfs_end_transaction(trans, root);
3921         btrfs_btree_balance_dirty(root);
3922
3923         return err;
3924 }
3925
3926 /*
3927  * this can truncate away extent items, csum items and directory items.
3928  * It starts at a high offset and removes keys until it can't find
3929  * any higher than new_size
3930  *
3931  * csum items that cross the new i_size are truncated to the new size
3932  * as well.
3933  *
3934  * min_type is the minimum key type to truncate down to.  If set to 0, this
3935  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3936  */
3937 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3938                                struct btrfs_root *root,
3939                                struct inode *inode,
3940                                u64 new_size, u32 min_type)
3941 {
3942         struct btrfs_path *path;
3943         struct extent_buffer *leaf;
3944         struct btrfs_file_extent_item *fi;
3945         struct btrfs_key key;
3946         struct btrfs_key found_key;
3947         u64 extent_start = 0;
3948         u64 extent_num_bytes = 0;
3949         u64 extent_offset = 0;
3950         u64 item_end = 0;
3951         u64 last_size = (u64)-1;
3952         u32 found_type = (u8)-1;
3953         int found_extent;
3954         int del_item;
3955         int pending_del_nr = 0;
3956         int pending_del_slot = 0;
3957         int extent_type = -1;
3958         int ret;
3959         int err = 0;
3960         u64 ino = btrfs_ino(inode);
3961
3962         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3963
3964         path = btrfs_alloc_path();
3965         if (!path)
3966                 return -ENOMEM;
3967         path->reada = -1;
3968
3969         /*
3970          * We want to drop from the next block forward in case this new size is
3971          * not block aligned since we will be keeping the last block of the
3972          * extent just the way it is.
3973          */
3974         if (root->ref_cows || root == root->fs_info->tree_root)
3975                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
3976                                         root->sectorsize), (u64)-1, 0);
3977
3978         /*
3979          * This function is also used to drop the items in the log tree before
3980          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
3981          * it is used to drop the loged items. So we shouldn't kill the delayed
3982          * items.
3983          */
3984         if (min_type == 0 && root == BTRFS_I(inode)->root)
3985                 btrfs_kill_delayed_inode_items(inode);
3986
3987         key.objectid = ino;
3988         key.offset = (u64)-1;
3989         key.type = (u8)-1;
3990
3991 search_again:
3992         path->leave_spinning = 1;
3993         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3994         if (ret < 0) {
3995                 err = ret;
3996                 goto out;
3997         }
3998
3999         if (ret > 0) {
4000                 /* there are no items in the tree for us to truncate, we're
4001                  * done
4002                  */
4003                 if (path->slots[0] == 0)
4004                         goto out;
4005                 path->slots[0]--;
4006         }
4007
4008         while (1) {
4009                 fi = NULL;
4010                 leaf = path->nodes[0];
4011                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4012                 found_type = btrfs_key_type(&found_key);
4013
4014                 if (found_key.objectid != ino)
4015                         break;
4016
4017                 if (found_type < min_type)
4018                         break;
4019
4020                 item_end = found_key.offset;
4021                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4022                         fi = btrfs_item_ptr(leaf, path->slots[0],
4023                                             struct btrfs_file_extent_item);
4024                         extent_type = btrfs_file_extent_type(leaf, fi);
4025                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4026                                 item_end +=
4027                                     btrfs_file_extent_num_bytes(leaf, fi);
4028                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4029                                 item_end += btrfs_file_extent_inline_len(leaf,
4030                                                          path->slots[0], fi);
4031                         }
4032                         item_end--;
4033                 }
4034                 if (found_type > min_type) {
4035                         del_item = 1;
4036                 } else {
4037                         if (item_end < new_size)
4038                                 break;
4039                         if (found_key.offset >= new_size)
4040                                 del_item = 1;
4041                         else
4042                                 del_item = 0;
4043                 }
4044                 found_extent = 0;
4045                 /* FIXME, shrink the extent if the ref count is only 1 */
4046                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4047                         goto delete;
4048
4049                 if (del_item)
4050                         last_size = found_key.offset;
4051                 else
4052                         last_size = new_size;
4053
4054                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4055                         u64 num_dec;
4056                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4057                         if (!del_item) {
4058                                 u64 orig_num_bytes =
4059                                         btrfs_file_extent_num_bytes(leaf, fi);
4060                                 extent_num_bytes = ALIGN(new_size -
4061                                                 found_key.offset,
4062                                                 root->sectorsize);
4063                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4064                                                          extent_num_bytes);
4065                                 num_dec = (orig_num_bytes -
4066                                            extent_num_bytes);
4067                                 if (root->ref_cows && extent_start != 0)
4068                                         inode_sub_bytes(inode, num_dec);
4069                                 btrfs_mark_buffer_dirty(leaf);
4070                         } else {
4071                                 extent_num_bytes =
4072                                         btrfs_file_extent_disk_num_bytes(leaf,
4073                                                                          fi);
4074                                 extent_offset = found_key.offset -
4075                                         btrfs_file_extent_offset(leaf, fi);
4076
4077                                 /* FIXME blocksize != 4096 */
4078                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4079                                 if (extent_start != 0) {
4080                                         found_extent = 1;
4081                                         if (root->ref_cows)
4082                                                 inode_sub_bytes(inode, num_dec);
4083                                 }
4084                         }
4085                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4086                         /*
4087                          * we can't truncate inline items that have had
4088                          * special encodings
4089                          */
4090                         if (!del_item &&
4091                             btrfs_file_extent_compression(leaf, fi) == 0 &&
4092                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4093                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4094                                 u32 size = new_size - found_key.offset;
4095
4096                                 if (root->ref_cows) {
4097                                         inode_sub_bytes(inode, item_end + 1 -
4098                                                         new_size);
4099                                 }
4100
4101                                 /*
4102                                  * update the ram bytes to properly reflect
4103                                  * the new size of our item
4104                                  */
4105                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4106                                 size =
4107                                     btrfs_file_extent_calc_inline_size(size);
4108                                 btrfs_truncate_item(root, path, size, 1);
4109                         } else if (root->ref_cows) {
4110                                 inode_sub_bytes(inode, item_end + 1 -
4111                                                 found_key.offset);
4112                         }
4113                 }
4114 delete:
4115                 if (del_item) {
4116                         if (!pending_del_nr) {
4117                                 /* no pending yet, add ourselves */
4118                                 pending_del_slot = path->slots[0];
4119                                 pending_del_nr = 1;
4120                         } else if (pending_del_nr &&
4121                                    path->slots[0] + 1 == pending_del_slot) {
4122                                 /* hop on the pending chunk */
4123                                 pending_del_nr++;
4124                                 pending_del_slot = path->slots[0];
4125                         } else {
4126                                 BUG();
4127                         }
4128                 } else {
4129                         break;
4130                 }
4131                 if (found_extent && (root->ref_cows ||
4132                                      root == root->fs_info->tree_root)) {
4133                         btrfs_set_path_blocking(path);
4134                         ret = btrfs_free_extent(trans, root, extent_start,
4135                                                 extent_num_bytes, 0,
4136                                                 btrfs_header_owner(leaf),
4137                                                 ino, extent_offset, 0);
4138                         BUG_ON(ret);
4139                 }
4140
4141                 if (found_type == BTRFS_INODE_ITEM_KEY)
4142                         break;
4143
4144                 if (path->slots[0] == 0 ||
4145                     path->slots[0] != pending_del_slot) {
4146                         if (pending_del_nr) {
4147                                 ret = btrfs_del_items(trans, root, path,
4148                                                 pending_del_slot,
4149                                                 pending_del_nr);
4150                                 if (ret) {
4151                                         btrfs_abort_transaction(trans,
4152                                                                 root, ret);
4153                                         goto error;
4154                                 }
4155                                 pending_del_nr = 0;
4156                         }
4157                         btrfs_release_path(path);
4158                         goto search_again;
4159                 } else {
4160                         path->slots[0]--;
4161                 }
4162         }
4163 out:
4164         if (pending_del_nr) {
4165                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4166                                       pending_del_nr);
4167                 if (ret)
4168                         btrfs_abort_transaction(trans, root, ret);
4169         }
4170 error:
4171         if (last_size != (u64)-1)
4172                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4173         btrfs_free_path(path);
4174         return err;
4175 }
4176
4177 /*
4178  * btrfs_truncate_page - read, zero a chunk and write a page
4179  * @inode - inode that we're zeroing
4180  * @from - the offset to start zeroing
4181  * @len - the length to zero, 0 to zero the entire range respective to the
4182  *      offset
4183  * @front - zero up to the offset instead of from the offset on
4184  *
4185  * This will find the page for the "from" offset and cow the page and zero the
4186  * part we want to zero.  This is used with truncate and hole punching.
4187  */
4188 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4189                         int front)
4190 {
4191         struct address_space *mapping = inode->i_mapping;
4192         struct btrfs_root *root = BTRFS_I(inode)->root;
4193         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4194         struct btrfs_ordered_extent *ordered;
4195         struct extent_state *cached_state = NULL;
4196         char *kaddr;
4197         u32 blocksize = root->sectorsize;
4198         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4199         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4200         struct page *page;
4201         gfp_t mask = btrfs_alloc_write_mask(mapping);
4202         int ret = 0;
4203         u64 page_start;
4204         u64 page_end;
4205
4206         if ((offset & (blocksize - 1)) == 0 &&
4207             (!len || ((len & (blocksize - 1)) == 0)))
4208                 goto out;
4209         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
4210         if (ret)
4211                 goto out;
4212
4213 again:
4214         page = find_or_create_page(mapping, index, mask);
4215         if (!page) {
4216                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4217                 ret = -ENOMEM;
4218                 goto out;
4219         }
4220
4221         page_start = page_offset(page);
4222         page_end = page_start + PAGE_CACHE_SIZE - 1;
4223
4224         if (!PageUptodate(page)) {
4225                 ret = btrfs_readpage(NULL, page);
4226                 lock_page(page);
4227                 if (page->mapping != mapping) {
4228                         unlock_page(page);
4229                         page_cache_release(page);
4230                         goto again;
4231                 }
4232                 if (!PageUptodate(page)) {
4233                         ret = -EIO;
4234                         goto out_unlock;
4235                 }
4236         }
4237         wait_on_page_writeback(page);
4238
4239         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4240         set_page_extent_mapped(page);
4241
4242         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4243         if (ordered) {
4244                 unlock_extent_cached(io_tree, page_start, page_end,
4245                                      &cached_state, GFP_NOFS);
4246                 unlock_page(page);
4247                 page_cache_release(page);
4248                 btrfs_start_ordered_extent(inode, ordered, 1);
4249                 btrfs_put_ordered_extent(ordered);
4250                 goto again;
4251         }
4252
4253         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4254                           EXTENT_DIRTY | EXTENT_DELALLOC |
4255                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4256                           0, 0, &cached_state, GFP_NOFS);
4257
4258         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4259                                         &cached_state);
4260         if (ret) {
4261                 unlock_extent_cached(io_tree, page_start, page_end,
4262                                      &cached_state, GFP_NOFS);
4263                 goto out_unlock;
4264         }
4265
4266         if (offset != PAGE_CACHE_SIZE) {
4267                 if (!len)
4268                         len = PAGE_CACHE_SIZE - offset;
4269                 kaddr = kmap(page);
4270                 if (front)
4271                         memset(kaddr, 0, offset);
4272                 else
4273                         memset(kaddr + offset, 0, len);
4274                 flush_dcache_page(page);
4275                 kunmap(page);
4276         }
4277         ClearPageChecked(page);
4278         set_page_dirty(page);
4279         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4280                              GFP_NOFS);
4281
4282 out_unlock:
4283         if (ret)
4284                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4285         unlock_page(page);
4286         page_cache_release(page);
4287 out:
4288         return ret;
4289 }
4290
4291 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4292                              u64 offset, u64 len)
4293 {
4294         struct btrfs_trans_handle *trans;
4295         int ret;
4296
4297         /*
4298          * Still need to make sure the inode looks like it's been updated so
4299          * that any holes get logged if we fsync.
4300          */
4301         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4302                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4303                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4304                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4305                 return 0;
4306         }
4307
4308         /*
4309          * 1 - for the one we're dropping
4310          * 1 - for the one we're adding
4311          * 1 - for updating the inode.
4312          */
4313         trans = btrfs_start_transaction(root, 3);
4314         if (IS_ERR(trans))
4315                 return PTR_ERR(trans);
4316
4317         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4318         if (ret) {
4319                 btrfs_abort_transaction(trans, root, ret);
4320                 btrfs_end_transaction(trans, root);
4321                 return ret;
4322         }
4323
4324         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4325                                        0, 0, len, 0, len, 0, 0, 0);
4326         if (ret)
4327                 btrfs_abort_transaction(trans, root, ret);
4328         else
4329                 btrfs_update_inode(trans, root, inode);
4330         btrfs_end_transaction(trans, root);
4331         return ret;
4332 }
4333
4334 /*
4335  * This function puts in dummy file extents for the area we're creating a hole
4336  * for.  So if we are truncating this file to a larger size we need to insert
4337  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4338  * the range between oldsize and size
4339  */
4340 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4341 {
4342         struct btrfs_root *root = BTRFS_I(inode)->root;
4343         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4344         struct extent_map *em = NULL;
4345         struct extent_state *cached_state = NULL;
4346         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4347         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4348         u64 block_end = ALIGN(size, root->sectorsize);
4349         u64 last_byte;
4350         u64 cur_offset;
4351         u64 hole_size;
4352         int err = 0;
4353
4354         /*
4355          * If our size started in the middle of a page we need to zero out the
4356          * rest of the page before we expand the i_size, otherwise we could
4357          * expose stale data.
4358          */
4359         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4360         if (err)
4361                 return err;
4362
4363         if (size <= hole_start)
4364                 return 0;
4365
4366         while (1) {
4367                 struct btrfs_ordered_extent *ordered;
4368
4369                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4370                                  &cached_state);
4371                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4372                                                      block_end - hole_start);
4373                 if (!ordered)
4374                         break;
4375                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4376                                      &cached_state, GFP_NOFS);
4377                 btrfs_start_ordered_extent(inode, ordered, 1);
4378                 btrfs_put_ordered_extent(ordered);
4379         }
4380
4381         cur_offset = hole_start;
4382         while (1) {
4383                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4384                                 block_end - cur_offset, 0);
4385                 if (IS_ERR(em)) {
4386                         err = PTR_ERR(em);
4387                         em = NULL;
4388                         break;
4389                 }
4390                 last_byte = min(extent_map_end(em), block_end);
4391                 last_byte = ALIGN(last_byte , root->sectorsize);
4392                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4393                         struct extent_map *hole_em;
4394                         hole_size = last_byte - cur_offset;
4395
4396                         err = maybe_insert_hole(root, inode, cur_offset,
4397                                                 hole_size);
4398                         if (err)
4399                                 break;
4400                         btrfs_drop_extent_cache(inode, cur_offset,
4401                                                 cur_offset + hole_size - 1, 0);
4402                         hole_em = alloc_extent_map();
4403                         if (!hole_em) {
4404                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4405                                         &BTRFS_I(inode)->runtime_flags);
4406                                 goto next;
4407                         }
4408                         hole_em->start = cur_offset;
4409                         hole_em->len = hole_size;
4410                         hole_em->orig_start = cur_offset;
4411
4412                         hole_em->block_start = EXTENT_MAP_HOLE;
4413                         hole_em->block_len = 0;
4414                         hole_em->orig_block_len = 0;
4415                         hole_em->ram_bytes = hole_size;
4416                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4417                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4418                         hole_em->generation = root->fs_info->generation;
4419
4420                         while (1) {
4421                                 write_lock(&em_tree->lock);
4422                                 err = add_extent_mapping(em_tree, hole_em, 1);
4423                                 write_unlock(&em_tree->lock);
4424                                 if (err != -EEXIST)
4425                                         break;
4426                                 btrfs_drop_extent_cache(inode, cur_offset,
4427                                                         cur_offset +
4428                                                         hole_size - 1, 0);
4429                         }
4430                         free_extent_map(hole_em);
4431                 }
4432 next:
4433                 free_extent_map(em);
4434                 em = NULL;
4435                 cur_offset = last_byte;
4436                 if (cur_offset >= block_end)
4437                         break;
4438         }
4439         free_extent_map(em);
4440         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4441                              GFP_NOFS);
4442         return err;
4443 }
4444
4445 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4446 {
4447         struct btrfs_root *root = BTRFS_I(inode)->root;
4448         struct btrfs_trans_handle *trans;
4449         loff_t oldsize = i_size_read(inode);
4450         loff_t newsize = attr->ia_size;
4451         int mask = attr->ia_valid;
4452         int ret;
4453
4454         /*
4455          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4456          * special case where we need to update the times despite not having
4457          * these flags set.  For all other operations the VFS set these flags
4458          * explicitly if it wants a timestamp update.
4459          */
4460         if (newsize != oldsize && (!(mask & (ATTR_CTIME | ATTR_MTIME))))
4461                 inode->i_ctime = inode->i_mtime = current_fs_time(inode->i_sb);
4462
4463         if (newsize > oldsize) {
4464                 truncate_pagecache(inode, newsize);
4465                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4466                 if (ret)
4467                         return ret;
4468
4469                 trans = btrfs_start_transaction(root, 1);
4470                 if (IS_ERR(trans))
4471                         return PTR_ERR(trans);
4472
4473                 i_size_write(inode, newsize);
4474                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4475                 ret = btrfs_update_inode(trans, root, inode);
4476                 btrfs_end_transaction(trans, root);
4477         } else {
4478
4479                 /*
4480                  * We're truncating a file that used to have good data down to
4481                  * zero. Make sure it gets into the ordered flush list so that
4482                  * any new writes get down to disk quickly.
4483                  */
4484                 if (newsize == 0)
4485                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4486                                 &BTRFS_I(inode)->runtime_flags);
4487
4488                 /*
4489                  * 1 for the orphan item we're going to add
4490                  * 1 for the orphan item deletion.
4491                  */
4492                 trans = btrfs_start_transaction(root, 2);
4493                 if (IS_ERR(trans))
4494                         return PTR_ERR(trans);
4495
4496                 /*
4497                  * We need to do this in case we fail at _any_ point during the
4498                  * actual truncate.  Once we do the truncate_setsize we could
4499                  * invalidate pages which forces any outstanding ordered io to
4500                  * be instantly completed which will give us extents that need
4501                  * to be truncated.  If we fail to get an orphan inode down we
4502                  * could have left over extents that were never meant to live,
4503                  * so we need to garuntee from this point on that everything
4504                  * will be consistent.
4505                  */
4506                 ret = btrfs_orphan_add(trans, inode);
4507                 btrfs_end_transaction(trans, root);
4508                 if (ret)
4509                         return ret;
4510
4511                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4512                 truncate_setsize(inode, newsize);
4513
4514                 /* Disable nonlocked read DIO to avoid the end less truncate */
4515                 btrfs_inode_block_unlocked_dio(inode);
4516                 inode_dio_wait(inode);
4517                 btrfs_inode_resume_unlocked_dio(inode);
4518
4519                 ret = btrfs_truncate(inode);
4520                 if (ret && inode->i_nlink) {
4521                         int err;
4522
4523                         /*
4524                          * failed to truncate, disk_i_size is only adjusted down
4525                          * as we remove extents, so it should represent the true
4526                          * size of the inode, so reset the in memory size and
4527                          * delete our orphan entry.
4528                          */
4529                         trans = btrfs_join_transaction(root);
4530                         if (IS_ERR(trans)) {
4531                                 btrfs_orphan_del(NULL, inode);
4532                                 return ret;
4533                         }
4534                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4535                         err = btrfs_orphan_del(trans, inode);
4536                         if (err)
4537                                 btrfs_abort_transaction(trans, root, err);
4538                         btrfs_end_transaction(trans, root);
4539                 }
4540         }
4541
4542         return ret;
4543 }
4544
4545 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4546 {
4547         struct inode *inode = dentry->d_inode;
4548         struct btrfs_root *root = BTRFS_I(inode)->root;
4549         int err;
4550
4551         if (btrfs_root_readonly(root))
4552                 return -EROFS;
4553
4554         err = inode_change_ok(inode, attr);
4555         if (err)
4556                 return err;
4557
4558         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4559                 err = btrfs_setsize(inode, attr);
4560                 if (err)
4561                         return err;
4562         }
4563
4564         if (attr->ia_valid) {
4565                 setattr_copy(inode, attr);
4566                 inode_inc_iversion(inode);
4567                 err = btrfs_dirty_inode(inode);
4568
4569                 if (!err && attr->ia_valid & ATTR_MODE)
4570                         err = btrfs_acl_chmod(inode);
4571         }
4572
4573         return err;
4574 }
4575
4576 /*
4577  * While truncating the inode pages during eviction, we get the VFS calling
4578  * btrfs_invalidatepage() against each page of the inode. This is slow because
4579  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4580  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4581  * extent_state structures over and over, wasting lots of time.
4582  *
4583  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4584  * those expensive operations on a per page basis and do only the ordered io
4585  * finishing, while we release here the extent_map and extent_state structures,
4586  * without the excessive merging and splitting.
4587  */
4588 static void evict_inode_truncate_pages(struct inode *inode)
4589 {
4590         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4591         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4592         struct rb_node *node;
4593
4594         ASSERT(inode->i_state & I_FREEING);
4595         truncate_inode_pages(&inode->i_data, 0);
4596
4597         write_lock(&map_tree->lock);
4598         while (!RB_EMPTY_ROOT(&map_tree->map)) {
4599                 struct extent_map *em;
4600
4601                 node = rb_first(&map_tree->map);
4602                 em = rb_entry(node, struct extent_map, rb_node);
4603                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4604                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4605                 remove_extent_mapping(map_tree, em);
4606                 free_extent_map(em);
4607         }
4608         write_unlock(&map_tree->lock);
4609
4610         spin_lock(&io_tree->lock);
4611         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4612                 struct extent_state *state;
4613                 struct extent_state *cached_state = NULL;
4614
4615                 node = rb_first(&io_tree->state);
4616                 state = rb_entry(node, struct extent_state, rb_node);
4617                 atomic_inc(&state->refs);
4618                 spin_unlock(&io_tree->lock);
4619
4620                 lock_extent_bits(io_tree, state->start, state->end,
4621                                  0, &cached_state);
4622                 clear_extent_bit(io_tree, state->start, state->end,
4623                                  EXTENT_LOCKED | EXTENT_DIRTY |
4624                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
4625                                  EXTENT_DEFRAG, 1, 1,
4626                                  &cached_state, GFP_NOFS);
4627                 free_extent_state(state);
4628
4629                 spin_lock(&io_tree->lock);
4630         }
4631         spin_unlock(&io_tree->lock);
4632 }
4633
4634 void btrfs_evict_inode(struct inode *inode)
4635 {
4636         struct btrfs_trans_handle *trans;
4637         struct btrfs_root *root = BTRFS_I(inode)->root;
4638         struct btrfs_block_rsv *rsv, *global_rsv;
4639         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
4640         int ret;
4641
4642         trace_btrfs_inode_evict(inode);
4643
4644         evict_inode_truncate_pages(inode);
4645
4646         if (inode->i_nlink &&
4647             ((btrfs_root_refs(&root->root_item) != 0 &&
4648               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4649              btrfs_is_free_space_inode(inode)))
4650                 goto no_delete;
4651
4652         if (is_bad_inode(inode)) {
4653                 btrfs_orphan_del(NULL, inode);
4654                 goto no_delete;
4655         }
4656         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
4657         btrfs_wait_ordered_range(inode, 0, (u64)-1);
4658
4659         if (root->fs_info->log_root_recovering) {
4660                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
4661                                  &BTRFS_I(inode)->runtime_flags));
4662                 goto no_delete;
4663         }
4664
4665         if (inode->i_nlink > 0) {
4666                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4667                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4668                 goto no_delete;
4669         }
4670
4671         ret = btrfs_commit_inode_delayed_inode(inode);
4672         if (ret) {
4673                 btrfs_orphan_del(NULL, inode);
4674                 goto no_delete;
4675         }
4676
4677         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
4678         if (!rsv) {
4679                 btrfs_orphan_del(NULL, inode);
4680                 goto no_delete;
4681         }
4682         rsv->size = min_size;
4683         rsv->failfast = 1;
4684         global_rsv = &root->fs_info->global_block_rsv;
4685
4686         btrfs_i_size_write(inode, 0);
4687
4688         /*
4689          * This is a bit simpler than btrfs_truncate since we've already
4690          * reserved our space for our orphan item in the unlink, so we just
4691          * need to reserve some slack space in case we add bytes and update
4692          * inode item when doing the truncate.
4693          */
4694         while (1) {
4695                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
4696                                              BTRFS_RESERVE_FLUSH_LIMIT);
4697
4698                 /*
4699                  * Try and steal from the global reserve since we will
4700                  * likely not use this space anyway, we want to try as
4701                  * hard as possible to get this to work.
4702                  */
4703                 if (ret)
4704                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
4705
4706                 if (ret) {
4707                         btrfs_warn(root->fs_info,
4708                                 "Could not get space for a delete, will truncate on mount %d",
4709                                 ret);
4710                         btrfs_orphan_del(NULL, inode);
4711                         btrfs_free_block_rsv(root, rsv);
4712                         goto no_delete;
4713                 }
4714
4715                 trans = btrfs_join_transaction(root);
4716                 if (IS_ERR(trans)) {
4717                         btrfs_orphan_del(NULL, inode);
4718                         btrfs_free_block_rsv(root, rsv);
4719                         goto no_delete;
4720                 }
4721
4722                 trans->block_rsv = rsv;
4723
4724                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4725                 if (ret != -ENOSPC)
4726                         break;
4727
4728                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4729                 btrfs_end_transaction(trans, root);
4730                 trans = NULL;
4731                 btrfs_btree_balance_dirty(root);
4732         }
4733
4734         btrfs_free_block_rsv(root, rsv);
4735
4736         /*
4737          * Errors here aren't a big deal, it just means we leave orphan items
4738          * in the tree.  They will be cleaned up on the next mount.
4739          */
4740         if (ret == 0) {
4741                 trans->block_rsv = root->orphan_block_rsv;
4742                 btrfs_orphan_del(trans, inode);
4743         } else {
4744                 btrfs_orphan_del(NULL, inode);
4745         }
4746
4747         trans->block_rsv = &root->fs_info->trans_block_rsv;
4748         if (!(root == root->fs_info->tree_root ||
4749               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4750                 btrfs_return_ino(root, btrfs_ino(inode));
4751
4752         btrfs_end_transaction(trans, root);
4753         btrfs_btree_balance_dirty(root);
4754 no_delete:
4755         btrfs_remove_delayed_node(inode);
4756         clear_inode(inode);
4757         return;
4758 }
4759
4760 /*
4761  * this returns the key found in the dir entry in the location pointer.
4762  * If no dir entries were found, location->objectid is 0.
4763  */
4764 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4765                                struct btrfs_key *location)
4766 {
4767         const char *name = dentry->d_name.name;
4768         int namelen = dentry->d_name.len;
4769         struct btrfs_dir_item *di;
4770         struct btrfs_path *path;
4771         struct btrfs_root *root = BTRFS_I(dir)->root;
4772         int ret = 0;
4773
4774         path = btrfs_alloc_path();
4775         if (!path)
4776                 return -ENOMEM;
4777
4778         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
4779                                     namelen, 0);
4780         if (IS_ERR(di))
4781                 ret = PTR_ERR(di);
4782
4783         if (IS_ERR_OR_NULL(di))
4784                 goto out_err;
4785
4786         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4787 out:
4788         btrfs_free_path(path);
4789         return ret;
4790 out_err:
4791         location->objectid = 0;
4792         goto out;
4793 }
4794
4795 /*
4796  * when we hit a tree root in a directory, the btrfs part of the inode
4797  * needs to be changed to reflect the root directory of the tree root.  This
4798  * is kind of like crossing a mount point.
4799  */
4800 static int fixup_tree_root_location(struct btrfs_root *root,
4801                                     struct inode *dir,
4802                                     struct dentry *dentry,
4803                                     struct btrfs_key *location,
4804                                     struct btrfs_root **sub_root)
4805 {
4806         struct btrfs_path *path;
4807         struct btrfs_root *new_root;
4808         struct btrfs_root_ref *ref;
4809         struct extent_buffer *leaf;
4810         int ret;
4811         int err = 0;
4812
4813         path = btrfs_alloc_path();
4814         if (!path) {
4815                 err = -ENOMEM;
4816                 goto out;
4817         }
4818
4819         err = -ENOENT;
4820         ret = btrfs_find_item(root->fs_info->tree_root, path,
4821                                 BTRFS_I(dir)->root->root_key.objectid,
4822                                 location->objectid, BTRFS_ROOT_REF_KEY, NULL);
4823         if (ret) {
4824                 if (ret < 0)
4825                         err = ret;
4826                 goto out;
4827         }
4828
4829         leaf = path->nodes[0];
4830         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
4831         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
4832             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
4833                 goto out;
4834
4835         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
4836                                    (unsigned long)(ref + 1),
4837                                    dentry->d_name.len);
4838         if (ret)
4839                 goto out;
4840
4841         btrfs_release_path(path);
4842
4843         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
4844         if (IS_ERR(new_root)) {
4845                 err = PTR_ERR(new_root);
4846                 goto out;
4847         }
4848
4849         *sub_root = new_root;
4850         location->objectid = btrfs_root_dirid(&new_root->root_item);
4851         location->type = BTRFS_INODE_ITEM_KEY;
4852         location->offset = 0;
4853         err = 0;
4854 out:
4855         btrfs_free_path(path);
4856         return err;
4857 }
4858
4859 static void inode_tree_add(struct inode *inode)
4860 {
4861         struct btrfs_root *root = BTRFS_I(inode)->root;
4862         struct btrfs_inode *entry;
4863         struct rb_node **p;
4864         struct rb_node *parent;
4865         struct rb_node *new = &BTRFS_I(inode)->rb_node;
4866         u64 ino = btrfs_ino(inode);
4867
4868         if (inode_unhashed(inode))
4869                 return;
4870         parent = NULL;
4871         spin_lock(&root->inode_lock);
4872         p = &root->inode_tree.rb_node;
4873         while (*p) {
4874                 parent = *p;
4875                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
4876
4877                 if (ino < btrfs_ino(&entry->vfs_inode))
4878                         p = &parent->rb_left;
4879                 else if (ino > btrfs_ino(&entry->vfs_inode))
4880                         p = &parent->rb_right;
4881                 else {
4882                         WARN_ON(!(entry->vfs_inode.i_state &
4883                                   (I_WILL_FREE | I_FREEING)));
4884                         rb_replace_node(parent, new, &root->inode_tree);
4885                         RB_CLEAR_NODE(parent);
4886                         spin_unlock(&root->inode_lock);
4887                         return;
4888                 }
4889         }
4890         rb_link_node(new, parent, p);
4891         rb_insert_color(new, &root->inode_tree);
4892         spin_unlock(&root->inode_lock);
4893 }
4894
4895 static void inode_tree_del(struct inode *inode)
4896 {
4897         struct btrfs_root *root = BTRFS_I(inode)->root;
4898         int empty = 0;
4899
4900         spin_lock(&root->inode_lock);
4901         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
4902                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
4903                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
4904                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4905         }
4906         spin_unlock(&root->inode_lock);
4907
4908         if (empty && btrfs_root_refs(&root->root_item) == 0) {
4909                 synchronize_srcu(&root->fs_info->subvol_srcu);
4910                 spin_lock(&root->inode_lock);
4911                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4912                 spin_unlock(&root->inode_lock);
4913                 if (empty)
4914                         btrfs_add_dead_root(root);
4915         }
4916 }
4917
4918 void btrfs_invalidate_inodes(struct btrfs_root *root)
4919 {
4920         struct rb_node *node;
4921         struct rb_node *prev;
4922         struct btrfs_inode *entry;
4923         struct inode *inode;
4924         u64 objectid = 0;
4925
4926         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
4927                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4928
4929         spin_lock(&root->inode_lock);
4930 again:
4931         node = root->inode_tree.rb_node;
4932         prev = NULL;
4933         while (node) {
4934                 prev = node;
4935                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4936
4937                 if (objectid < btrfs_ino(&entry->vfs_inode))
4938                         node = node->rb_left;
4939                 else if (objectid > btrfs_ino(&entry->vfs_inode))
4940                         node = node->rb_right;
4941                 else
4942                         break;
4943         }
4944         if (!node) {
4945                 while (prev) {
4946                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4947                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
4948                                 node = prev;
4949                                 break;
4950                         }
4951                         prev = rb_next(prev);
4952                 }
4953         }
4954         while (node) {
4955                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4956                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
4957                 inode = igrab(&entry->vfs_inode);
4958                 if (inode) {
4959                         spin_unlock(&root->inode_lock);
4960                         if (atomic_read(&inode->i_count) > 1)
4961                                 d_prune_aliases(inode);
4962                         /*
4963                          * btrfs_drop_inode will have it removed from
4964                          * the inode cache when its usage count
4965                          * hits zero.
4966                          */
4967                         iput(inode);
4968                         cond_resched();
4969                         spin_lock(&root->inode_lock);
4970                         goto again;
4971                 }
4972
4973                 if (cond_resched_lock(&root->inode_lock))
4974                         goto again;
4975
4976                 node = rb_next(node);
4977         }
4978         spin_unlock(&root->inode_lock);
4979 }
4980
4981 static int btrfs_init_locked_inode(struct inode *inode, void *p)
4982 {
4983         struct btrfs_iget_args *args = p;
4984         inode->i_ino = args->location->objectid;
4985         memcpy(&BTRFS_I(inode)->location, args->location,
4986                sizeof(*args->location));
4987         BTRFS_I(inode)->root = args->root;
4988         return 0;
4989 }
4990
4991 static int btrfs_find_actor(struct inode *inode, void *opaque)
4992 {
4993         struct btrfs_iget_args *args = opaque;
4994         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
4995                 args->root == BTRFS_I(inode)->root;
4996 }
4997
4998 static struct inode *btrfs_iget_locked(struct super_block *s,
4999                                        struct btrfs_key *location,
5000                                        struct btrfs_root *root)
5001 {
5002         struct inode *inode;
5003         struct btrfs_iget_args args;
5004         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5005
5006         args.location = location;
5007         args.root = root;
5008
5009         inode = iget5_locked(s, hashval, btrfs_find_actor,
5010                              btrfs_init_locked_inode,
5011                              (void *)&args);
5012         return inode;
5013 }
5014
5015 /* Get an inode object given its location and corresponding root.
5016  * Returns in *is_new if the inode was read from disk
5017  */
5018 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5019                          struct btrfs_root *root, int *new)
5020 {
5021         struct inode *inode;
5022
5023         inode = btrfs_iget_locked(s, location, root);
5024         if (!inode)
5025                 return ERR_PTR(-ENOMEM);
5026
5027         if (inode->i_state & I_NEW) {
5028                 btrfs_read_locked_inode(inode);
5029                 if (!is_bad_inode(inode)) {
5030                         inode_tree_add(inode);
5031                         unlock_new_inode(inode);
5032                         if (new)
5033                                 *new = 1;
5034                 } else {
5035                         unlock_new_inode(inode);
5036                         iput(inode);
5037                         inode = ERR_PTR(-ESTALE);
5038                 }
5039         }
5040
5041         return inode;
5042 }
5043
5044 static struct inode *new_simple_dir(struct super_block *s,
5045                                     struct btrfs_key *key,
5046                                     struct btrfs_root *root)
5047 {
5048         struct inode *inode = new_inode(s);
5049
5050         if (!inode)
5051                 return ERR_PTR(-ENOMEM);
5052
5053         BTRFS_I(inode)->root = root;
5054         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5055         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5056
5057         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5058         inode->i_op = &btrfs_dir_ro_inode_operations;
5059         inode->i_fop = &simple_dir_operations;
5060         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5061         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5062
5063         return inode;
5064 }
5065
5066 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5067 {
5068         struct inode *inode;
5069         struct btrfs_root *root = BTRFS_I(dir)->root;
5070         struct btrfs_root *sub_root = root;
5071         struct btrfs_key location;
5072         int index;
5073         int ret = 0;
5074
5075         if (dentry->d_name.len > BTRFS_NAME_LEN)
5076                 return ERR_PTR(-ENAMETOOLONG);
5077
5078         ret = btrfs_inode_by_name(dir, dentry, &location);
5079         if (ret < 0)
5080                 return ERR_PTR(ret);
5081
5082         if (location.objectid == 0)
5083                 return ERR_PTR(-ENOENT);
5084
5085         if (location.type == BTRFS_INODE_ITEM_KEY) {
5086                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5087                 return inode;
5088         }
5089
5090         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5091
5092         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5093         ret = fixup_tree_root_location(root, dir, dentry,
5094                                        &location, &sub_root);
5095         if (ret < 0) {
5096                 if (ret != -ENOENT)
5097                         inode = ERR_PTR(ret);
5098                 else
5099                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5100         } else {
5101                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5102         }
5103         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5104
5105         if (!IS_ERR(inode) && root != sub_root) {
5106                 down_read(&root->fs_info->cleanup_work_sem);
5107                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5108                         ret = btrfs_orphan_cleanup(sub_root);
5109                 up_read(&root->fs_info->cleanup_work_sem);
5110                 if (ret) {
5111                         iput(inode);
5112                         inode = ERR_PTR(ret);
5113                 }
5114         }
5115
5116         return inode;
5117 }
5118
5119 static int btrfs_dentry_delete(const struct dentry *dentry)
5120 {
5121         struct btrfs_root *root;
5122         struct inode *inode = dentry->d_inode;
5123
5124         if (!inode && !IS_ROOT(dentry))
5125                 inode = dentry->d_parent->d_inode;
5126
5127         if (inode) {
5128                 root = BTRFS_I(inode)->root;
5129                 if (btrfs_root_refs(&root->root_item) == 0)
5130                         return 1;
5131
5132                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5133                         return 1;
5134         }
5135         return 0;
5136 }
5137
5138 static void btrfs_dentry_release(struct dentry *dentry)
5139 {
5140         if (dentry->d_fsdata)
5141                 kfree(dentry->d_fsdata);
5142 }
5143
5144 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5145                                    unsigned int flags)
5146 {
5147         struct inode *inode;
5148
5149         inode = btrfs_lookup_dentry(dir, dentry);
5150         if (IS_ERR(inode)) {
5151                 if (PTR_ERR(inode) == -ENOENT)
5152                         inode = NULL;
5153                 else
5154                         return ERR_CAST(inode);
5155         }
5156
5157         return d_materialise_unique(dentry, inode);
5158 }
5159
5160 unsigned char btrfs_filetype_table[] = {
5161         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5162 };
5163
5164 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5165 {
5166         struct inode *inode = file_inode(file);
5167         struct btrfs_root *root = BTRFS_I(inode)->root;
5168         struct btrfs_item *item;
5169         struct btrfs_dir_item *di;
5170         struct btrfs_key key;
5171         struct btrfs_key found_key;
5172         struct btrfs_path *path;
5173         struct list_head ins_list;
5174         struct list_head del_list;
5175         int ret;
5176         struct extent_buffer *leaf;
5177         int slot;
5178         unsigned char d_type;
5179         int over = 0;
5180         u32 di_cur;
5181         u32 di_total;
5182         u32 di_len;
5183         int key_type = BTRFS_DIR_INDEX_KEY;
5184         char tmp_name[32];
5185         char *name_ptr;
5186         int name_len;
5187         int is_curr = 0;        /* ctx->pos points to the current index? */
5188
5189         /* FIXME, use a real flag for deciding about the key type */
5190         if (root->fs_info->tree_root == root)
5191                 key_type = BTRFS_DIR_ITEM_KEY;
5192
5193         if (!dir_emit_dots(file, ctx))
5194                 return 0;
5195
5196         path = btrfs_alloc_path();
5197         if (!path)
5198                 return -ENOMEM;
5199
5200         path->reada = 1;
5201
5202         if (key_type == BTRFS_DIR_INDEX_KEY) {
5203                 INIT_LIST_HEAD(&ins_list);
5204                 INIT_LIST_HEAD(&del_list);
5205                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5206         }
5207
5208         btrfs_set_key_type(&key, key_type);
5209         key.offset = ctx->pos;
5210         key.objectid = btrfs_ino(inode);
5211
5212         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5213         if (ret < 0)
5214                 goto err;
5215
5216         while (1) {
5217                 leaf = path->nodes[0];
5218                 slot = path->slots[0];
5219                 if (slot >= btrfs_header_nritems(leaf)) {
5220                         ret = btrfs_next_leaf(root, path);
5221                         if (ret < 0)
5222                                 goto err;
5223                         else if (ret > 0)
5224                                 break;
5225                         continue;
5226                 }
5227
5228                 item = btrfs_item_nr(slot);
5229                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5230
5231                 if (found_key.objectid != key.objectid)
5232                         break;
5233                 if (btrfs_key_type(&found_key) != key_type)
5234                         break;
5235                 if (found_key.offset < ctx->pos)
5236                         goto next;
5237                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5238                     btrfs_should_delete_dir_index(&del_list,
5239                                                   found_key.offset))
5240                         goto next;
5241
5242                 ctx->pos = found_key.offset;
5243                 is_curr = 1;
5244
5245                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5246                 di_cur = 0;
5247                 di_total = btrfs_item_size(leaf, item);
5248
5249                 while (di_cur < di_total) {
5250                         struct btrfs_key location;
5251
5252                         if (verify_dir_item(root, leaf, di))
5253                                 break;
5254
5255                         name_len = btrfs_dir_name_len(leaf, di);
5256                         if (name_len <= sizeof(tmp_name)) {
5257                                 name_ptr = tmp_name;
5258                         } else {
5259                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5260                                 if (!name_ptr) {
5261                                         ret = -ENOMEM;
5262                                         goto err;
5263                                 }
5264                         }
5265                         read_extent_buffer(leaf, name_ptr,
5266                                            (unsigned long)(di + 1), name_len);
5267
5268                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5269                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5270
5271
5272                         /* is this a reference to our own snapshot? If so
5273                          * skip it.
5274                          *
5275                          * In contrast to old kernels, we insert the snapshot's
5276                          * dir item and dir index after it has been created, so
5277                          * we won't find a reference to our own snapshot. We
5278                          * still keep the following code for backward
5279                          * compatibility.
5280                          */
5281                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5282                             location.objectid == root->root_key.objectid) {
5283                                 over = 0;
5284                                 goto skip;
5285                         }
5286                         over = !dir_emit(ctx, name_ptr, name_len,
5287                                        location.objectid, d_type);
5288
5289 skip:
5290                         if (name_ptr != tmp_name)
5291                                 kfree(name_ptr);
5292
5293                         if (over)
5294                                 goto nopos;
5295                         di_len = btrfs_dir_name_len(leaf, di) +
5296                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5297                         di_cur += di_len;
5298                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5299                 }
5300 next:
5301                 path->slots[0]++;
5302         }
5303
5304         if (key_type == BTRFS_DIR_INDEX_KEY) {
5305                 if (is_curr)
5306                         ctx->pos++;
5307                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5308                 if (ret)
5309                         goto nopos;
5310         }
5311
5312         /* Reached end of directory/root. Bump pos past the last item. */
5313         ctx->pos++;
5314
5315         /*
5316          * Stop new entries from being returned after we return the last
5317          * entry.
5318          *
5319          * New directory entries are assigned a strictly increasing
5320          * offset.  This means that new entries created during readdir
5321          * are *guaranteed* to be seen in the future by that readdir.
5322          * This has broken buggy programs which operate on names as
5323          * they're returned by readdir.  Until we re-use freed offsets
5324          * we have this hack to stop new entries from being returned
5325          * under the assumption that they'll never reach this huge
5326          * offset.
5327          *
5328          * This is being careful not to overflow 32bit loff_t unless the
5329          * last entry requires it because doing so has broken 32bit apps
5330          * in the past.
5331          */
5332         if (key_type == BTRFS_DIR_INDEX_KEY) {
5333                 if (ctx->pos >= INT_MAX)
5334                         ctx->pos = LLONG_MAX;
5335                 else
5336                         ctx->pos = INT_MAX;
5337         }
5338 nopos:
5339         ret = 0;
5340 err:
5341         if (key_type == BTRFS_DIR_INDEX_KEY)
5342                 btrfs_put_delayed_items(&ins_list, &del_list);
5343         btrfs_free_path(path);
5344         return ret;
5345 }
5346
5347 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5348 {
5349         struct btrfs_root *root = BTRFS_I(inode)->root;
5350         struct btrfs_trans_handle *trans;
5351         int ret = 0;
5352         bool nolock = false;
5353
5354         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5355                 return 0;
5356
5357         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5358                 nolock = true;
5359
5360         if (wbc->sync_mode == WB_SYNC_ALL) {
5361                 if (nolock)
5362                         trans = btrfs_join_transaction_nolock(root);
5363                 else
5364                         trans = btrfs_join_transaction(root);
5365                 if (IS_ERR(trans))
5366                         return PTR_ERR(trans);
5367                 ret = btrfs_commit_transaction(trans, root);
5368         }
5369         return ret;
5370 }
5371
5372 /*
5373  * This is somewhat expensive, updating the tree every time the
5374  * inode changes.  But, it is most likely to find the inode in cache.
5375  * FIXME, needs more benchmarking...there are no reasons other than performance
5376  * to keep or drop this code.
5377  */
5378 static int btrfs_dirty_inode(struct inode *inode)
5379 {
5380         struct btrfs_root *root = BTRFS_I(inode)->root;
5381         struct btrfs_trans_handle *trans;
5382         int ret;
5383
5384         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5385                 return 0;
5386
5387         trans = btrfs_join_transaction(root);
5388         if (IS_ERR(trans))
5389                 return PTR_ERR(trans);
5390
5391         ret = btrfs_update_inode(trans, root, inode);
5392         if (ret && ret == -ENOSPC) {
5393                 /* whoops, lets try again with the full transaction */
5394                 btrfs_end_transaction(trans, root);
5395                 trans = btrfs_start_transaction(root, 1);
5396                 if (IS_ERR(trans))
5397                         return PTR_ERR(trans);
5398
5399                 ret = btrfs_update_inode(trans, root, inode);
5400         }
5401         btrfs_end_transaction(trans, root);
5402         if (BTRFS_I(inode)->delayed_node)
5403                 btrfs_balance_delayed_items(root);
5404
5405         return ret;
5406 }
5407
5408 /*
5409  * This is a copy of file_update_time.  We need this so we can return error on
5410  * ENOSPC for updating the inode in the case of file write and mmap writes.
5411  */
5412 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5413                              int flags)
5414 {
5415         struct btrfs_root *root = BTRFS_I(inode)->root;
5416
5417         if (btrfs_root_readonly(root))
5418                 return -EROFS;
5419
5420         if (flags & S_VERSION)
5421                 inode_inc_iversion(inode);
5422         if (flags & S_CTIME)
5423                 inode->i_ctime = *now;
5424         if (flags & S_MTIME)
5425                 inode->i_mtime = *now;
5426         if (flags & S_ATIME)
5427                 inode->i_atime = *now;
5428         return btrfs_dirty_inode(inode);
5429 }
5430
5431 /*
5432  * find the highest existing sequence number in a directory
5433  * and then set the in-memory index_cnt variable to reflect
5434  * free sequence numbers
5435  */
5436 static int btrfs_set_inode_index_count(struct inode *inode)
5437 {
5438         struct btrfs_root *root = BTRFS_I(inode)->root;
5439         struct btrfs_key key, found_key;
5440         struct btrfs_path *path;
5441         struct extent_buffer *leaf;
5442         int ret;
5443
5444         key.objectid = btrfs_ino(inode);
5445         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
5446         key.offset = (u64)-1;
5447
5448         path = btrfs_alloc_path();
5449         if (!path)
5450                 return -ENOMEM;
5451
5452         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5453         if (ret < 0)
5454                 goto out;
5455         /* FIXME: we should be able to handle this */
5456         if (ret == 0)
5457                 goto out;
5458         ret = 0;
5459
5460         /*
5461          * MAGIC NUMBER EXPLANATION:
5462          * since we search a directory based on f_pos we have to start at 2
5463          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5464          * else has to start at 2
5465          */
5466         if (path->slots[0] == 0) {
5467                 BTRFS_I(inode)->index_cnt = 2;
5468                 goto out;
5469         }
5470
5471         path->slots[0]--;
5472
5473         leaf = path->nodes[0];
5474         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5475
5476         if (found_key.objectid != btrfs_ino(inode) ||
5477             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
5478                 BTRFS_I(inode)->index_cnt = 2;
5479                 goto out;
5480         }
5481
5482         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
5483 out:
5484         btrfs_free_path(path);
5485         return ret;
5486 }
5487
5488 /*
5489  * helper to find a free sequence number in a given directory.  This current
5490  * code is very simple, later versions will do smarter things in the btree
5491  */
5492 int btrfs_set_inode_index(struct inode *dir, u64 *index)
5493 {
5494         int ret = 0;
5495
5496         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
5497                 ret = btrfs_inode_delayed_dir_index_count(dir);
5498                 if (ret) {
5499                         ret = btrfs_set_inode_index_count(dir);
5500                         if (ret)
5501                                 return ret;
5502                 }
5503         }
5504
5505         *index = BTRFS_I(dir)->index_cnt;
5506         BTRFS_I(dir)->index_cnt++;
5507
5508         return ret;
5509 }
5510
5511 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5512                                      struct btrfs_root *root,
5513                                      struct inode *dir,
5514                                      const char *name, int name_len,
5515                                      u64 ref_objectid, u64 objectid,
5516                                      umode_t mode, u64 *index)
5517 {
5518         struct inode *inode;
5519         struct btrfs_inode_item *inode_item;
5520         struct btrfs_key *location;
5521         struct btrfs_path *path;
5522         struct btrfs_inode_ref *ref;
5523         struct btrfs_key key[2];
5524         u32 sizes[2];
5525         unsigned long ptr;
5526         int ret;
5527
5528         path = btrfs_alloc_path();
5529         if (!path)
5530                 return ERR_PTR(-ENOMEM);
5531
5532         inode = new_inode(root->fs_info->sb);
5533         if (!inode) {
5534                 btrfs_free_path(path);
5535                 return ERR_PTR(-ENOMEM);
5536         }
5537
5538         /*
5539          * we have to initialize this early, so we can reclaim the inode
5540          * number if we fail afterwards in this function.
5541          */
5542         inode->i_ino = objectid;
5543
5544         if (dir) {
5545                 trace_btrfs_inode_request(dir);
5546
5547                 ret = btrfs_set_inode_index(dir, index);
5548                 if (ret) {
5549                         btrfs_free_path(path);
5550                         iput(inode);
5551                         return ERR_PTR(ret);
5552                 }
5553         }
5554         /*
5555          * index_cnt is ignored for everything but a dir,
5556          * btrfs_get_inode_index_count has an explanation for the magic
5557          * number
5558          */
5559         BTRFS_I(inode)->index_cnt = 2;
5560         BTRFS_I(inode)->dir_index = *index;
5561         BTRFS_I(inode)->root = root;
5562         BTRFS_I(inode)->generation = trans->transid;
5563         inode->i_generation = BTRFS_I(inode)->generation;
5564
5565         /*
5566          * We could have gotten an inode number from somebody who was fsynced
5567          * and then removed in this same transaction, so let's just set full
5568          * sync since it will be a full sync anyway and this will blow away the
5569          * old info in the log.
5570          */
5571         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5572
5573         key[0].objectid = objectid;
5574         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
5575         key[0].offset = 0;
5576
5577         /*
5578          * Start new inodes with an inode_ref. This is slightly more
5579          * efficient for small numbers of hard links since they will
5580          * be packed into one item. Extended refs will kick in if we
5581          * add more hard links than can fit in the ref item.
5582          */
5583         key[1].objectid = objectid;
5584         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
5585         key[1].offset = ref_objectid;
5586
5587         sizes[0] = sizeof(struct btrfs_inode_item);
5588         sizes[1] = name_len + sizeof(*ref);
5589
5590         path->leave_spinning = 1;
5591         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
5592         if (ret != 0)
5593                 goto fail;
5594
5595         inode_init_owner(inode, dir, mode);
5596         inode_set_bytes(inode, 0);
5597         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5598         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5599                                   struct btrfs_inode_item);
5600         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
5601                              sizeof(*inode_item));
5602         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5603
5604         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5605                              struct btrfs_inode_ref);
5606         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5607         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5608         ptr = (unsigned long)(ref + 1);
5609         write_extent_buffer(path->nodes[0], name, ptr, name_len);
5610
5611         btrfs_mark_buffer_dirty(path->nodes[0]);
5612         btrfs_free_path(path);
5613
5614         location = &BTRFS_I(inode)->location;
5615         location->objectid = objectid;
5616         location->offset = 0;
5617         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
5618
5619         btrfs_inherit_iflags(inode, dir);
5620
5621         if (S_ISREG(mode)) {
5622                 if (btrfs_test_opt(root, NODATASUM))
5623                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5624                 if (btrfs_test_opt(root, NODATACOW))
5625                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5626                                 BTRFS_INODE_NODATASUM;
5627         }
5628
5629         btrfs_insert_inode_hash(inode);
5630         inode_tree_add(inode);
5631
5632         trace_btrfs_inode_new(inode);
5633         btrfs_set_inode_last_trans(trans, inode);
5634
5635         btrfs_update_root_times(trans, root);
5636
5637         ret = btrfs_inode_inherit_props(trans, inode, dir);
5638         if (ret)
5639                 btrfs_err(root->fs_info,
5640                           "error inheriting props for ino %llu (root %llu): %d",
5641                           btrfs_ino(inode), root->root_key.objectid, ret);
5642
5643         return inode;
5644 fail:
5645         if (dir)
5646                 BTRFS_I(dir)->index_cnt--;
5647         btrfs_free_path(path);
5648         iput(inode);
5649         return ERR_PTR(ret);
5650 }
5651
5652 static inline u8 btrfs_inode_type(struct inode *inode)
5653 {
5654         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
5655 }
5656
5657 /*
5658  * utility function to add 'inode' into 'parent_inode' with
5659  * a give name and a given sequence number.
5660  * if 'add_backref' is true, also insert a backref from the
5661  * inode to the parent directory.
5662  */
5663 int btrfs_add_link(struct btrfs_trans_handle *trans,
5664                    struct inode *parent_inode, struct inode *inode,
5665                    const char *name, int name_len, int add_backref, u64 index)
5666 {
5667         int ret = 0;
5668         struct btrfs_key key;
5669         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
5670         u64 ino = btrfs_ino(inode);
5671         u64 parent_ino = btrfs_ino(parent_inode);
5672
5673         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5674                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
5675         } else {
5676                 key.objectid = ino;
5677                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
5678                 key.offset = 0;
5679         }
5680
5681         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5682                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
5683                                          key.objectid, root->root_key.objectid,
5684                                          parent_ino, index, name, name_len);
5685         } else if (add_backref) {
5686                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5687                                              parent_ino, index);
5688         }
5689
5690         /* Nothing to clean up yet */
5691         if (ret)
5692                 return ret;
5693
5694         ret = btrfs_insert_dir_item(trans, root, name, name_len,
5695                                     parent_inode, &key,
5696                                     btrfs_inode_type(inode), index);
5697         if (ret == -EEXIST || ret == -EOVERFLOW)
5698                 goto fail_dir_item;
5699         else if (ret) {
5700                 btrfs_abort_transaction(trans, root, ret);
5701                 return ret;
5702         }
5703
5704         btrfs_i_size_write(parent_inode, parent_inode->i_size +
5705                            name_len * 2);
5706         inode_inc_iversion(parent_inode);
5707         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
5708         ret = btrfs_update_inode(trans, root, parent_inode);
5709         if (ret)
5710                 btrfs_abort_transaction(trans, root, ret);
5711         return ret;
5712
5713 fail_dir_item:
5714         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5715                 u64 local_index;
5716                 int err;
5717                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
5718                                  key.objectid, root->root_key.objectid,
5719                                  parent_ino, &local_index, name, name_len);
5720
5721         } else if (add_backref) {
5722                 u64 local_index;
5723                 int err;
5724
5725                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5726                                           ino, parent_ino, &local_index);
5727         }
5728         return ret;
5729 }
5730
5731 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5732                             struct inode *dir, struct dentry *dentry,
5733                             struct inode *inode, int backref, u64 index)
5734 {
5735         int err = btrfs_add_link(trans, dir, inode,
5736                                  dentry->d_name.name, dentry->d_name.len,
5737                                  backref, index);
5738         if (err > 0)
5739                 err = -EEXIST;
5740         return err;
5741 }
5742
5743 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5744                         umode_t mode, dev_t rdev)
5745 {
5746         struct btrfs_trans_handle *trans;
5747         struct btrfs_root *root = BTRFS_I(dir)->root;
5748         struct inode *inode = NULL;
5749         int err;
5750         int drop_inode = 0;
5751         u64 objectid;
5752         u64 index = 0;
5753
5754         if (!new_valid_dev(rdev))
5755                 return -EINVAL;
5756
5757         /*
5758          * 2 for inode item and ref
5759          * 2 for dir items
5760          * 1 for xattr if selinux is on
5761          */
5762         trans = btrfs_start_transaction(root, 5);
5763         if (IS_ERR(trans))
5764                 return PTR_ERR(trans);
5765
5766         err = btrfs_find_free_ino(root, &objectid);
5767         if (err)
5768                 goto out_unlock;
5769
5770         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5771                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5772                                 mode, &index);
5773         if (IS_ERR(inode)) {
5774                 err = PTR_ERR(inode);
5775                 goto out_unlock;
5776         }
5777
5778         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5779         if (err) {
5780                 drop_inode = 1;
5781                 goto out_unlock;
5782         }
5783
5784         /*
5785         * If the active LSM wants to access the inode during
5786         * d_instantiate it needs these. Smack checks to see
5787         * if the filesystem supports xattrs by looking at the
5788         * ops vector.
5789         */
5790
5791         inode->i_op = &btrfs_special_inode_operations;
5792         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5793         if (err)
5794                 drop_inode = 1;
5795         else {
5796                 init_special_inode(inode, inode->i_mode, rdev);
5797                 btrfs_update_inode(trans, root, inode);
5798                 d_instantiate(dentry, inode);
5799         }
5800 out_unlock:
5801         btrfs_end_transaction(trans, root);
5802         btrfs_balance_delayed_items(root);
5803         btrfs_btree_balance_dirty(root);
5804         if (drop_inode) {
5805                 inode_dec_link_count(inode);
5806                 iput(inode);
5807         }
5808         return err;
5809 }
5810
5811 static int btrfs_create(struct inode *dir, struct dentry *dentry,
5812                         umode_t mode, bool excl)
5813 {
5814         struct btrfs_trans_handle *trans;
5815         struct btrfs_root *root = BTRFS_I(dir)->root;
5816         struct inode *inode = NULL;
5817         int drop_inode_on_err = 0;
5818         int err;
5819         u64 objectid;
5820         u64 index = 0;
5821
5822         /*
5823          * 2 for inode item and ref
5824          * 2 for dir items
5825          * 1 for xattr if selinux is on
5826          */
5827         trans = btrfs_start_transaction(root, 5);
5828         if (IS_ERR(trans))
5829                 return PTR_ERR(trans);
5830
5831         err = btrfs_find_free_ino(root, &objectid);
5832         if (err)
5833                 goto out_unlock;
5834
5835         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5836                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5837                                 mode, &index);
5838         if (IS_ERR(inode)) {
5839                 err = PTR_ERR(inode);
5840                 goto out_unlock;
5841         }
5842         drop_inode_on_err = 1;
5843
5844         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5845         if (err)
5846                 goto out_unlock;
5847
5848         err = btrfs_update_inode(trans, root, inode);
5849         if (err)
5850                 goto out_unlock;
5851
5852         /*
5853         * If the active LSM wants to access the inode during
5854         * d_instantiate it needs these. Smack checks to see
5855         * if the filesystem supports xattrs by looking at the
5856         * ops vector.
5857         */
5858         inode->i_fop = &btrfs_file_operations;
5859         inode->i_op = &btrfs_file_inode_operations;
5860
5861         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5862         if (err)
5863                 goto out_unlock;
5864
5865         inode->i_mapping->a_ops = &btrfs_aops;
5866         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
5867         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
5868         d_instantiate(dentry, inode);
5869
5870 out_unlock:
5871         btrfs_end_transaction(trans, root);
5872         if (err && drop_inode_on_err) {
5873                 inode_dec_link_count(inode);
5874                 iput(inode);
5875         }
5876         btrfs_balance_delayed_items(root);
5877         btrfs_btree_balance_dirty(root);
5878         return err;
5879 }
5880
5881 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
5882                       struct dentry *dentry)
5883 {
5884         struct btrfs_trans_handle *trans;
5885         struct btrfs_root *root = BTRFS_I(dir)->root;
5886         struct inode *inode = old_dentry->d_inode;
5887         u64 index;
5888         int err;
5889         int drop_inode = 0;
5890
5891         /* do not allow sys_link's with other subvols of the same device */
5892         if (root->objectid != BTRFS_I(inode)->root->objectid)
5893                 return -EXDEV;
5894
5895         if (inode->i_nlink >= BTRFS_LINK_MAX)
5896                 return -EMLINK;
5897
5898         err = btrfs_set_inode_index(dir, &index);
5899         if (err)
5900                 goto fail;
5901
5902         /*
5903          * 2 items for inode and inode ref
5904          * 2 items for dir items
5905          * 1 item for parent inode
5906          */
5907         trans = btrfs_start_transaction(root, 5);
5908         if (IS_ERR(trans)) {
5909                 err = PTR_ERR(trans);
5910                 goto fail;
5911         }
5912
5913         /* There are several dir indexes for this inode, clear the cache. */
5914         BTRFS_I(inode)->dir_index = 0ULL;
5915         inc_nlink(inode);
5916         inode_inc_iversion(inode);
5917         inode->i_ctime = CURRENT_TIME;
5918         ihold(inode);
5919         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
5920
5921         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
5922
5923         if (err) {
5924                 drop_inode = 1;
5925         } else {
5926                 struct dentry *parent = dentry->d_parent;
5927                 err = btrfs_update_inode(trans, root, inode);
5928                 if (err)
5929                         goto fail;
5930                 d_instantiate(dentry, inode);
5931                 btrfs_log_new_name(trans, inode, NULL, parent);
5932         }
5933
5934         btrfs_end_transaction(trans, root);
5935         btrfs_balance_delayed_items(root);
5936 fail:
5937         if (drop_inode) {
5938                 inode_dec_link_count(inode);
5939                 iput(inode);
5940         }
5941         btrfs_btree_balance_dirty(root);
5942         return err;
5943 }
5944
5945 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
5946 {
5947         struct inode *inode = NULL;
5948         struct btrfs_trans_handle *trans;
5949         struct btrfs_root *root = BTRFS_I(dir)->root;
5950         int err = 0;
5951         int drop_on_err = 0;
5952         u64 objectid = 0;
5953         u64 index = 0;
5954
5955         /*
5956          * 2 items for inode and ref
5957          * 2 items for dir items
5958          * 1 for xattr if selinux is on
5959          */
5960         trans = btrfs_start_transaction(root, 5);
5961         if (IS_ERR(trans))
5962                 return PTR_ERR(trans);
5963
5964         err = btrfs_find_free_ino(root, &objectid);
5965         if (err)
5966                 goto out_fail;
5967
5968         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5969                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5970                                 S_IFDIR | mode, &index);
5971         if (IS_ERR(inode)) {
5972                 err = PTR_ERR(inode);
5973                 goto out_fail;
5974         }
5975
5976         drop_on_err = 1;
5977
5978         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5979         if (err)
5980                 goto out_fail;
5981
5982         inode->i_op = &btrfs_dir_inode_operations;
5983         inode->i_fop = &btrfs_dir_file_operations;
5984
5985         btrfs_i_size_write(inode, 0);
5986         err = btrfs_update_inode(trans, root, inode);
5987         if (err)
5988                 goto out_fail;
5989
5990         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
5991                              dentry->d_name.len, 0, index);
5992         if (err)
5993                 goto out_fail;
5994
5995         d_instantiate(dentry, inode);
5996         drop_on_err = 0;
5997
5998 out_fail:
5999         btrfs_end_transaction(trans, root);
6000         if (drop_on_err)
6001                 iput(inode);
6002         btrfs_balance_delayed_items(root);
6003         btrfs_btree_balance_dirty(root);
6004         return err;
6005 }
6006
6007 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6008  * and an extent that you want to insert, deal with overlap and insert
6009  * the new extent into the tree.
6010  */
6011 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6012                                 struct extent_map *existing,
6013                                 struct extent_map *em,
6014                                 u64 map_start, u64 map_len)
6015 {
6016         u64 start_diff;
6017
6018         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6019         start_diff = map_start - em->start;
6020         em->start = map_start;
6021         em->len = map_len;
6022         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6023             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6024                 em->block_start += start_diff;
6025                 em->block_len -= start_diff;
6026         }
6027         return add_extent_mapping(em_tree, em, 0);
6028 }
6029
6030 static noinline int uncompress_inline(struct btrfs_path *path,
6031                                       struct inode *inode, struct page *page,
6032                                       size_t pg_offset, u64 extent_offset,
6033                                       struct btrfs_file_extent_item *item)
6034 {
6035         int ret;
6036         struct extent_buffer *leaf = path->nodes[0];
6037         char *tmp;
6038         size_t max_size;
6039         unsigned long inline_size;
6040         unsigned long ptr;
6041         int compress_type;
6042
6043         WARN_ON(pg_offset != 0);
6044         compress_type = btrfs_file_extent_compression(leaf, item);
6045         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6046         inline_size = btrfs_file_extent_inline_item_len(leaf,
6047                                         btrfs_item_nr(path->slots[0]));
6048         tmp = kmalloc(inline_size, GFP_NOFS);
6049         if (!tmp)
6050                 return -ENOMEM;
6051         ptr = btrfs_file_extent_inline_start(item);
6052
6053         read_extent_buffer(leaf, tmp, ptr, inline_size);
6054
6055         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
6056         ret = btrfs_decompress(compress_type, tmp, page,
6057                                extent_offset, inline_size, max_size);
6058         if (ret) {
6059                 char *kaddr = kmap_atomic(page);
6060                 unsigned long copy_size = min_t(u64,
6061                                   PAGE_CACHE_SIZE - pg_offset,
6062                                   max_size - extent_offset);
6063                 memset(kaddr + pg_offset, 0, copy_size);
6064                 kunmap_atomic(kaddr);
6065         }
6066         kfree(tmp);
6067         return 0;
6068 }
6069
6070 /*
6071  * a bit scary, this does extent mapping from logical file offset to the disk.
6072  * the ugly parts come from merging extents from the disk with the in-ram
6073  * representation.  This gets more complex because of the data=ordered code,
6074  * where the in-ram extents might be locked pending data=ordered completion.
6075  *
6076  * This also copies inline extents directly into the page.
6077  */
6078
6079 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6080                                     size_t pg_offset, u64 start, u64 len,
6081                                     int create)
6082 {
6083         int ret;
6084         int err = 0;
6085         u64 bytenr;
6086         u64 extent_start = 0;
6087         u64 extent_end = 0;
6088         u64 objectid = btrfs_ino(inode);
6089         u32 found_type;
6090         struct btrfs_path *path = NULL;
6091         struct btrfs_root *root = BTRFS_I(inode)->root;
6092         struct btrfs_file_extent_item *item;
6093         struct extent_buffer *leaf;
6094         struct btrfs_key found_key;
6095         struct extent_map *em = NULL;
6096         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6097         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6098         struct btrfs_trans_handle *trans = NULL;
6099         int compress_type;
6100
6101 again:
6102         read_lock(&em_tree->lock);
6103         em = lookup_extent_mapping(em_tree, start, len);
6104         if (em)
6105                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6106         read_unlock(&em_tree->lock);
6107
6108         if (em) {
6109                 if (em->start > start || em->start + em->len <= start)
6110                         free_extent_map(em);
6111                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6112                         free_extent_map(em);
6113                 else
6114                         goto out;
6115         }
6116         em = alloc_extent_map();
6117         if (!em) {
6118                 err = -ENOMEM;
6119                 goto out;
6120         }
6121         em->bdev = root->fs_info->fs_devices->latest_bdev;
6122         em->start = EXTENT_MAP_HOLE;
6123         em->orig_start = EXTENT_MAP_HOLE;
6124         em->len = (u64)-1;
6125         em->block_len = (u64)-1;
6126
6127         if (!path) {
6128                 path = btrfs_alloc_path();
6129                 if (!path) {
6130                         err = -ENOMEM;
6131                         goto out;
6132                 }
6133                 /*
6134                  * Chances are we'll be called again, so go ahead and do
6135                  * readahead
6136                  */
6137                 path->reada = 1;
6138         }
6139
6140         ret = btrfs_lookup_file_extent(trans, root, path,
6141                                        objectid, start, trans != NULL);
6142         if (ret < 0) {
6143                 err = ret;
6144                 goto out;
6145         }
6146
6147         if (ret != 0) {
6148                 if (path->slots[0] == 0)
6149                         goto not_found;
6150                 path->slots[0]--;
6151         }
6152
6153         leaf = path->nodes[0];
6154         item = btrfs_item_ptr(leaf, path->slots[0],
6155                               struct btrfs_file_extent_item);
6156         /* are we inside the extent that was found? */
6157         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6158         found_type = btrfs_key_type(&found_key);
6159         if (found_key.objectid != objectid ||
6160             found_type != BTRFS_EXTENT_DATA_KEY) {
6161                 /*
6162                  * If we backup past the first extent we want to move forward
6163                  * and see if there is an extent in front of us, otherwise we'll
6164                  * say there is a hole for our whole search range which can
6165                  * cause problems.
6166                  */
6167                 extent_end = start;
6168                 goto next;
6169         }
6170
6171         found_type = btrfs_file_extent_type(leaf, item);
6172         extent_start = found_key.offset;
6173         compress_type = btrfs_file_extent_compression(leaf, item);
6174         if (found_type == BTRFS_FILE_EXTENT_REG ||
6175             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6176                 extent_end = extent_start +
6177                        btrfs_file_extent_num_bytes(leaf, item);
6178         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6179                 size_t size;
6180                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6181                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6182         }
6183 next:
6184         if (start >= extent_end) {
6185                 path->slots[0]++;
6186                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6187                         ret = btrfs_next_leaf(root, path);
6188                         if (ret < 0) {
6189                                 err = ret;
6190                                 goto out;
6191                         }
6192                         if (ret > 0)
6193                                 goto not_found;
6194                         leaf = path->nodes[0];
6195                 }
6196                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6197                 if (found_key.objectid != objectid ||
6198                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6199                         goto not_found;
6200                 if (start + len <= found_key.offset)
6201                         goto not_found;
6202                 em->start = start;
6203                 em->orig_start = start;
6204                 em->len = found_key.offset - start;
6205                 goto not_found_em;
6206         }
6207
6208         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, item);
6209         if (found_type == BTRFS_FILE_EXTENT_REG ||
6210             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6211                 em->start = extent_start;
6212                 em->len = extent_end - extent_start;
6213                 em->orig_start = extent_start -
6214                                  btrfs_file_extent_offset(leaf, item);
6215                 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf,
6216                                                                       item);
6217                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
6218                 if (bytenr == 0) {
6219                         em->block_start = EXTENT_MAP_HOLE;
6220                         goto insert;
6221                 }
6222                 if (compress_type != BTRFS_COMPRESS_NONE) {
6223                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
6224                         em->compress_type = compress_type;
6225                         em->block_start = bytenr;
6226                         em->block_len = em->orig_block_len;
6227                 } else {
6228                         bytenr += btrfs_file_extent_offset(leaf, item);
6229                         em->block_start = bytenr;
6230                         em->block_len = em->len;
6231                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
6232                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6233                 }
6234                 goto insert;
6235         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6236                 unsigned long ptr;
6237                 char *map;
6238                 size_t size;
6239                 size_t extent_offset;
6240                 size_t copy_size;
6241
6242                 em->block_start = EXTENT_MAP_INLINE;
6243                 if (!page || create) {
6244                         em->start = extent_start;
6245                         em->len = extent_end - extent_start;
6246                         goto out;
6247                 }
6248
6249                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6250                 extent_offset = page_offset(page) + pg_offset - extent_start;
6251                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6252                                 size - extent_offset);
6253                 em->start = extent_start + extent_offset;
6254                 em->len = ALIGN(copy_size, root->sectorsize);
6255                 em->orig_block_len = em->len;
6256                 em->orig_start = em->start;
6257                 if (compress_type) {
6258                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
6259                         em->compress_type = compress_type;
6260                 }
6261                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6262                 if (create == 0 && !PageUptodate(page)) {
6263                         if (btrfs_file_extent_compression(leaf, item) !=
6264                             BTRFS_COMPRESS_NONE) {
6265                                 ret = uncompress_inline(path, inode, page,
6266                                                         pg_offset,
6267                                                         extent_offset, item);
6268                                 BUG_ON(ret); /* -ENOMEM */
6269                         } else {
6270                                 map = kmap(page);
6271                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6272                                                    copy_size);
6273                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6274                                         memset(map + pg_offset + copy_size, 0,
6275                                                PAGE_CACHE_SIZE - pg_offset -
6276                                                copy_size);
6277                                 }
6278                                 kunmap(page);
6279                         }
6280                         flush_dcache_page(page);
6281                 } else if (create && PageUptodate(page)) {
6282                         BUG();
6283                         if (!trans) {
6284                                 kunmap(page);
6285                                 free_extent_map(em);
6286                                 em = NULL;
6287
6288                                 btrfs_release_path(path);
6289                                 trans = btrfs_join_transaction(root);
6290
6291                                 if (IS_ERR(trans))
6292                                         return ERR_CAST(trans);
6293                                 goto again;
6294                         }
6295                         map = kmap(page);
6296                         write_extent_buffer(leaf, map + pg_offset, ptr,
6297                                             copy_size);
6298                         kunmap(page);
6299                         btrfs_mark_buffer_dirty(leaf);
6300                 }
6301                 set_extent_uptodate(io_tree, em->start,
6302                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6303                 goto insert;
6304         } else {
6305                 WARN(1, KERN_ERR "btrfs unknown found_type %d\n", found_type);
6306         }
6307 not_found:
6308         em->start = start;
6309         em->orig_start = start;
6310         em->len = len;
6311 not_found_em:
6312         em->block_start = EXTENT_MAP_HOLE;
6313         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6314 insert:
6315         btrfs_release_path(path);
6316         if (em->start > start || extent_map_end(em) <= start) {
6317                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6318                         em->start, em->len, start, len);
6319                 err = -EIO;
6320                 goto out;
6321         }
6322
6323         err = 0;
6324         write_lock(&em_tree->lock);
6325         ret = add_extent_mapping(em_tree, em, 0);
6326         /* it is possible that someone inserted the extent into the tree
6327          * while we had the lock dropped.  It is also possible that
6328          * an overlapping map exists in the tree
6329          */
6330         if (ret == -EEXIST) {
6331                 struct extent_map *existing;
6332
6333                 ret = 0;
6334
6335                 existing = lookup_extent_mapping(em_tree, start, len);
6336                 if (existing && (existing->start > start ||
6337                     existing->start + existing->len <= start)) {
6338                         free_extent_map(existing);
6339                         existing = NULL;
6340                 }
6341                 if (!existing) {
6342                         existing = lookup_extent_mapping(em_tree, em->start,
6343                                                          em->len);
6344                         if (existing) {
6345                                 err = merge_extent_mapping(em_tree, existing,
6346                                                            em, start,
6347                                                            root->sectorsize);
6348                                 free_extent_map(existing);
6349                                 if (err) {
6350                                         free_extent_map(em);
6351                                         em = NULL;
6352                                 }
6353                         } else {
6354                                 err = -EIO;
6355                                 free_extent_map(em);
6356                                 em = NULL;
6357                         }
6358                 } else {
6359                         free_extent_map(em);
6360                         em = existing;
6361                         err = 0;
6362                 }
6363         }
6364         write_unlock(&em_tree->lock);
6365 out:
6366
6367         trace_btrfs_get_extent(root, em);
6368
6369         if (path)
6370                 btrfs_free_path(path);
6371         if (trans) {
6372                 ret = btrfs_end_transaction(trans, root);
6373                 if (!err)
6374                         err = ret;
6375         }
6376         if (err) {
6377                 free_extent_map(em);
6378                 return ERR_PTR(err);
6379         }
6380         BUG_ON(!em); /* Error is always set */
6381         return em;
6382 }
6383
6384 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
6385                                            size_t pg_offset, u64 start, u64 len,
6386                                            int create)
6387 {
6388         struct extent_map *em;
6389         struct extent_map *hole_em = NULL;
6390         u64 range_start = start;
6391         u64 end;
6392         u64 found;
6393         u64 found_end;
6394         int err = 0;
6395
6396         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6397         if (IS_ERR(em))
6398                 return em;
6399         if (em) {
6400                 /*
6401                  * if our em maps to
6402                  * -  a hole or
6403                  * -  a pre-alloc extent,
6404                  * there might actually be delalloc bytes behind it.
6405                  */
6406                 if (em->block_start != EXTENT_MAP_HOLE &&
6407                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6408                         return em;
6409                 else
6410                         hole_em = em;
6411         }
6412
6413         /* check to see if we've wrapped (len == -1 or similar) */
6414         end = start + len;
6415         if (end < start)
6416                 end = (u64)-1;
6417         else
6418                 end -= 1;
6419
6420         em = NULL;
6421
6422         /* ok, we didn't find anything, lets look for delalloc */
6423         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
6424                                  end, len, EXTENT_DELALLOC, 1);
6425         found_end = range_start + found;
6426         if (found_end < range_start)
6427                 found_end = (u64)-1;
6428
6429         /*
6430          * we didn't find anything useful, return
6431          * the original results from get_extent()
6432          */
6433         if (range_start > end || found_end <= start) {
6434                 em = hole_em;
6435                 hole_em = NULL;
6436                 goto out;
6437         }
6438
6439         /* adjust the range_start to make sure it doesn't
6440          * go backwards from the start they passed in
6441          */
6442         range_start = max(start, range_start);
6443         found = found_end - range_start;
6444
6445         if (found > 0) {
6446                 u64 hole_start = start;
6447                 u64 hole_len = len;
6448
6449                 em = alloc_extent_map();
6450                 if (!em) {
6451                         err = -ENOMEM;
6452                         goto out;
6453                 }
6454                 /*
6455                  * when btrfs_get_extent can't find anything it
6456                  * returns one huge hole
6457                  *
6458                  * make sure what it found really fits our range, and
6459                  * adjust to make sure it is based on the start from
6460                  * the caller
6461                  */
6462                 if (hole_em) {
6463                         u64 calc_end = extent_map_end(hole_em);
6464
6465                         if (calc_end <= start || (hole_em->start > end)) {
6466                                 free_extent_map(hole_em);
6467                                 hole_em = NULL;
6468                         } else {
6469                                 hole_start = max(hole_em->start, start);
6470                                 hole_len = calc_end - hole_start;
6471                         }
6472                 }
6473                 em->bdev = NULL;
6474                 if (hole_em && range_start > hole_start) {
6475                         /* our hole starts before our delalloc, so we
6476                          * have to return just the parts of the hole
6477                          * that go until  the delalloc starts
6478                          */
6479                         em->len = min(hole_len,
6480                                       range_start - hole_start);
6481                         em->start = hole_start;
6482                         em->orig_start = hole_start;
6483                         /*
6484                          * don't adjust block start at all,
6485                          * it is fixed at EXTENT_MAP_HOLE
6486                          */
6487                         em->block_start = hole_em->block_start;
6488                         em->block_len = hole_len;
6489                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6490                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6491                 } else {
6492                         em->start = range_start;
6493                         em->len = found;
6494                         em->orig_start = range_start;
6495                         em->block_start = EXTENT_MAP_DELALLOC;
6496                         em->block_len = found;
6497                 }
6498         } else if (hole_em) {
6499                 return hole_em;
6500         }
6501 out:
6502
6503         free_extent_map(hole_em);
6504         if (err) {
6505                 free_extent_map(em);
6506                 return ERR_PTR(err);
6507         }
6508         return em;
6509 }
6510
6511 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6512                                                   u64 start, u64 len)
6513 {
6514         struct btrfs_root *root = BTRFS_I(inode)->root;
6515         struct extent_map *em;
6516         struct btrfs_key ins;
6517         u64 alloc_hint;
6518         int ret;
6519
6520         alloc_hint = get_extent_allocation_hint(inode, start, len);
6521         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
6522                                    alloc_hint, &ins, 1);
6523         if (ret)
6524                 return ERR_PTR(ret);
6525
6526         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
6527                               ins.offset, ins.offset, ins.offset, 0);
6528         if (IS_ERR(em)) {
6529                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
6530                 return em;
6531         }
6532
6533         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
6534                                            ins.offset, ins.offset, 0);
6535         if (ret) {
6536                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
6537                 free_extent_map(em);
6538                 return ERR_PTR(ret);
6539         }
6540
6541         return em;
6542 }
6543
6544 /*
6545  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6546  * block must be cow'd
6547  */
6548 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6549                               u64 *orig_start, u64 *orig_block_len,
6550                               u64 *ram_bytes)
6551 {
6552         struct btrfs_trans_handle *trans;
6553         struct btrfs_path *path;
6554         int ret;
6555         struct extent_buffer *leaf;
6556         struct btrfs_root *root = BTRFS_I(inode)->root;
6557         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6558         struct btrfs_file_extent_item *fi;
6559         struct btrfs_key key;
6560         u64 disk_bytenr;
6561         u64 backref_offset;
6562         u64 extent_end;
6563         u64 num_bytes;
6564         int slot;
6565         int found_type;
6566         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6567
6568         path = btrfs_alloc_path();
6569         if (!path)
6570                 return -ENOMEM;
6571
6572         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
6573                                        offset, 0);
6574         if (ret < 0)
6575                 goto out;
6576
6577         slot = path->slots[0];
6578         if (ret == 1) {
6579                 if (slot == 0) {
6580                         /* can't find the item, must cow */
6581                         ret = 0;
6582                         goto out;
6583                 }
6584                 slot--;
6585         }
6586         ret = 0;
6587         leaf = path->nodes[0];
6588         btrfs_item_key_to_cpu(leaf, &key, slot);
6589         if (key.objectid != btrfs_ino(inode) ||
6590             key.type != BTRFS_EXTENT_DATA_KEY) {
6591                 /* not our file or wrong item type, must cow */
6592                 goto out;
6593         }
6594
6595         if (key.offset > offset) {
6596                 /* Wrong offset, must cow */
6597                 goto out;
6598         }
6599
6600         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6601         found_type = btrfs_file_extent_type(leaf, fi);
6602         if (found_type != BTRFS_FILE_EXTENT_REG &&
6603             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6604                 /* not a regular extent, must cow */
6605                 goto out;
6606         }
6607
6608         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6609                 goto out;
6610
6611         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6612         if (extent_end <= offset)
6613                 goto out;
6614
6615         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6616         if (disk_bytenr == 0)
6617                 goto out;
6618
6619         if (btrfs_file_extent_compression(leaf, fi) ||
6620             btrfs_file_extent_encryption(leaf, fi) ||
6621             btrfs_file_extent_other_encoding(leaf, fi))
6622                 goto out;
6623
6624         backref_offset = btrfs_file_extent_offset(leaf, fi);
6625
6626         if (orig_start) {
6627                 *orig_start = key.offset - backref_offset;
6628                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6629                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6630         }
6631
6632         if (btrfs_extent_readonly(root, disk_bytenr))
6633                 goto out;
6634
6635         num_bytes = min(offset + *len, extent_end) - offset;
6636         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6637                 u64 range_end;
6638
6639                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
6640                 ret = test_range_bit(io_tree, offset, range_end,
6641                                      EXTENT_DELALLOC, 0, NULL);
6642                 if (ret) {
6643                         ret = -EAGAIN;
6644                         goto out;
6645                 }
6646         }
6647
6648         btrfs_release_path(path);
6649
6650         /*
6651          * look for other files referencing this extent, if we
6652          * find any we must cow
6653          */
6654         trans = btrfs_join_transaction(root);
6655         if (IS_ERR(trans)) {
6656                 ret = 0;
6657                 goto out;
6658         }
6659
6660         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
6661                                     key.offset - backref_offset, disk_bytenr);
6662         btrfs_end_transaction(trans, root);
6663         if (ret) {
6664                 ret = 0;
6665                 goto out;
6666         }
6667
6668         /*
6669          * adjust disk_bytenr and num_bytes to cover just the bytes
6670          * in this extent we are about to write.  If there
6671          * are any csums in that range we have to cow in order
6672          * to keep the csums correct
6673          */
6674         disk_bytenr += backref_offset;
6675         disk_bytenr += offset - key.offset;
6676         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
6677                                 goto out;
6678         /*
6679          * all of the above have passed, it is safe to overwrite this extent
6680          * without cow
6681          */
6682         *len = num_bytes;
6683         ret = 1;
6684 out:
6685         btrfs_free_path(path);
6686         return ret;
6687 }
6688
6689 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
6690                               struct extent_state **cached_state, int writing)
6691 {
6692         struct btrfs_ordered_extent *ordered;
6693         int ret = 0;
6694
6695         while (1) {
6696                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6697                                  0, cached_state);
6698                 /*
6699                  * We're concerned with the entire range that we're going to be
6700                  * doing DIO to, so we need to make sure theres no ordered
6701                  * extents in this range.
6702                  */
6703                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
6704                                                      lockend - lockstart + 1);
6705
6706                 /*
6707                  * We need to make sure there are no buffered pages in this
6708                  * range either, we could have raced between the invalidate in
6709                  * generic_file_direct_write and locking the extent.  The
6710                  * invalidate needs to happen so that reads after a write do not
6711                  * get stale data.
6712                  */
6713                 if (!ordered && (!writing ||
6714                     !test_range_bit(&BTRFS_I(inode)->io_tree,
6715                                     lockstart, lockend, EXTENT_UPTODATE, 0,
6716                                     *cached_state)))
6717                         break;
6718
6719                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6720                                      cached_state, GFP_NOFS);
6721
6722                 if (ordered) {
6723                         btrfs_start_ordered_extent(inode, ordered, 1);
6724                         btrfs_put_ordered_extent(ordered);
6725                 } else {
6726                         /* Screw you mmap */
6727                         ret = filemap_write_and_wait_range(inode->i_mapping,
6728                                                            lockstart,
6729                                                            lockend);
6730                         if (ret)
6731                                 break;
6732
6733                         /*
6734                          * If we found a page that couldn't be invalidated just
6735                          * fall back to buffered.
6736                          */
6737                         ret = invalidate_inode_pages2_range(inode->i_mapping,
6738                                         lockstart >> PAGE_CACHE_SHIFT,
6739                                         lockend >> PAGE_CACHE_SHIFT);
6740                         if (ret)
6741                                 break;
6742                 }
6743
6744                 cond_resched();
6745         }
6746
6747         return ret;
6748 }
6749
6750 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
6751                                            u64 len, u64 orig_start,
6752                                            u64 block_start, u64 block_len,
6753                                            u64 orig_block_len, u64 ram_bytes,
6754                                            int type)
6755 {
6756         struct extent_map_tree *em_tree;
6757         struct extent_map *em;
6758         struct btrfs_root *root = BTRFS_I(inode)->root;
6759         int ret;
6760
6761         em_tree = &BTRFS_I(inode)->extent_tree;
6762         em = alloc_extent_map();
6763         if (!em)
6764                 return ERR_PTR(-ENOMEM);
6765
6766         em->start = start;
6767         em->orig_start = orig_start;
6768         em->mod_start = start;
6769         em->mod_len = len;
6770         em->len = len;
6771         em->block_len = block_len;
6772         em->block_start = block_start;
6773         em->bdev = root->fs_info->fs_devices->latest_bdev;
6774         em->orig_block_len = orig_block_len;
6775         em->ram_bytes = ram_bytes;
6776         em->generation = -1;
6777         set_bit(EXTENT_FLAG_PINNED, &em->flags);
6778         if (type == BTRFS_ORDERED_PREALLOC)
6779                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
6780
6781         do {
6782                 btrfs_drop_extent_cache(inode, em->start,
6783                                 em->start + em->len - 1, 0);
6784                 write_lock(&em_tree->lock);
6785                 ret = add_extent_mapping(em_tree, em, 1);
6786                 write_unlock(&em_tree->lock);
6787         } while (ret == -EEXIST);
6788
6789         if (ret) {
6790                 free_extent_map(em);
6791                 return ERR_PTR(ret);
6792         }
6793
6794         return em;
6795 }
6796
6797
6798 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
6799                                    struct buffer_head *bh_result, int create)
6800 {
6801         struct extent_map *em;
6802         struct btrfs_root *root = BTRFS_I(inode)->root;
6803         struct extent_state *cached_state = NULL;
6804         u64 start = iblock << inode->i_blkbits;
6805         u64 lockstart, lockend;
6806         u64 len = bh_result->b_size;
6807         int unlock_bits = EXTENT_LOCKED;
6808         int ret = 0;
6809
6810         if (create)
6811                 unlock_bits |= EXTENT_DELALLOC | EXTENT_DIRTY;
6812         else
6813                 len = min_t(u64, len, root->sectorsize);
6814
6815         lockstart = start;
6816         lockend = start + len - 1;
6817
6818         /*
6819          * If this errors out it's because we couldn't invalidate pagecache for
6820          * this range and we need to fallback to buffered.
6821          */
6822         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
6823                 return -ENOTBLK;
6824
6825         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
6826         if (IS_ERR(em)) {
6827                 ret = PTR_ERR(em);
6828                 goto unlock_err;
6829         }
6830
6831         /*
6832          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
6833          * io.  INLINE is special, and we could probably kludge it in here, but
6834          * it's still buffered so for safety lets just fall back to the generic
6835          * buffered path.
6836          *
6837          * For COMPRESSED we _have_ to read the entire extent in so we can
6838          * decompress it, so there will be buffering required no matter what we
6839          * do, so go ahead and fallback to buffered.
6840          *
6841          * We return -ENOTBLK because thats what makes DIO go ahead and go back
6842          * to buffered IO.  Don't blame me, this is the price we pay for using
6843          * the generic code.
6844          */
6845         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
6846             em->block_start == EXTENT_MAP_INLINE) {
6847                 free_extent_map(em);
6848                 ret = -ENOTBLK;
6849                 goto unlock_err;
6850         }
6851
6852         /* Just a good old fashioned hole, return */
6853         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
6854                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
6855                 free_extent_map(em);
6856                 goto unlock_err;
6857         }
6858
6859         /*
6860          * We don't allocate a new extent in the following cases
6861          *
6862          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
6863          * existing extent.
6864          * 2) The extent is marked as PREALLOC.  We're good to go here and can
6865          * just use the extent.
6866          *
6867          */
6868         if (!create) {
6869                 len = min(len, em->len - (start - em->start));
6870                 lockstart = start + len;
6871                 goto unlock;
6872         }
6873
6874         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
6875             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
6876              em->block_start != EXTENT_MAP_HOLE)) {
6877                 int type;
6878                 int ret;
6879                 u64 block_start, orig_start, orig_block_len, ram_bytes;
6880
6881                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6882                         type = BTRFS_ORDERED_PREALLOC;
6883                 else
6884                         type = BTRFS_ORDERED_NOCOW;
6885                 len = min(len, em->len - (start - em->start));
6886                 block_start = em->block_start + (start - em->start);
6887
6888                 if (can_nocow_extent(inode, start, &len, &orig_start,
6889                                      &orig_block_len, &ram_bytes) == 1) {
6890                         if (type == BTRFS_ORDERED_PREALLOC) {
6891                                 free_extent_map(em);
6892                                 em = create_pinned_em(inode, start, len,
6893                                                        orig_start,
6894                                                        block_start, len,
6895                                                        orig_block_len,
6896                                                        ram_bytes, type);
6897                                 if (IS_ERR(em))
6898                                         goto unlock_err;
6899                         }
6900
6901                         ret = btrfs_add_ordered_extent_dio(inode, start,
6902                                            block_start, len, len, type);
6903                         if (ret) {
6904                                 free_extent_map(em);
6905                                 goto unlock_err;
6906                         }
6907                         goto unlock;
6908                 }
6909         }
6910
6911         /*
6912          * this will cow the extent, reset the len in case we changed
6913          * it above
6914          */
6915         len = bh_result->b_size;
6916         free_extent_map(em);
6917         em = btrfs_new_extent_direct(inode, start, len);
6918         if (IS_ERR(em)) {
6919                 ret = PTR_ERR(em);
6920                 goto unlock_err;
6921         }
6922         len = min(len, em->len - (start - em->start));
6923 unlock:
6924         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
6925                 inode->i_blkbits;
6926         bh_result->b_size = len;
6927         bh_result->b_bdev = em->bdev;
6928         set_buffer_mapped(bh_result);
6929         if (create) {
6930                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6931                         set_buffer_new(bh_result);
6932
6933                 /*
6934                  * Need to update the i_size under the extent lock so buffered
6935                  * readers will get the updated i_size when we unlock.
6936                  */
6937                 if (start + len > i_size_read(inode))
6938                         i_size_write(inode, start + len);
6939
6940                 spin_lock(&BTRFS_I(inode)->lock);
6941                 BTRFS_I(inode)->outstanding_extents++;
6942                 spin_unlock(&BTRFS_I(inode)->lock);
6943
6944                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6945                                      lockstart + len - 1, EXTENT_DELALLOC, NULL,
6946                                      &cached_state, GFP_NOFS);
6947                 BUG_ON(ret);
6948         }
6949
6950         /*
6951          * In the case of write we need to clear and unlock the entire range,
6952          * in the case of read we need to unlock only the end area that we
6953          * aren't using if there is any left over space.
6954          */
6955         if (lockstart < lockend) {
6956                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6957                                  lockend, unlock_bits, 1, 0,
6958                                  &cached_state, GFP_NOFS);
6959         } else {
6960                 free_extent_state(cached_state);
6961         }
6962
6963         free_extent_map(em);
6964
6965         return 0;
6966
6967 unlock_err:
6968         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6969                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
6970         return ret;
6971 }
6972
6973 static void btrfs_endio_direct_read(struct bio *bio, int err)
6974 {
6975         struct btrfs_dio_private *dip = bio->bi_private;
6976         struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
6977         struct bio_vec *bvec = bio->bi_io_vec;
6978         struct inode *inode = dip->inode;
6979         struct btrfs_root *root = BTRFS_I(inode)->root;
6980         struct bio *dio_bio;
6981         u32 *csums = (u32 *)dip->csum;
6982         int index = 0;
6983         u64 start;
6984
6985         start = dip->logical_offset;
6986         do {
6987                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
6988                         struct page *page = bvec->bv_page;
6989                         char *kaddr;
6990                         u32 csum = ~(u32)0;
6991                         unsigned long flags;
6992
6993                         local_irq_save(flags);
6994                         kaddr = kmap_atomic(page);
6995                         csum = btrfs_csum_data(kaddr + bvec->bv_offset,
6996                                                csum, bvec->bv_len);
6997                         btrfs_csum_final(csum, (char *)&csum);
6998                         kunmap_atomic(kaddr);
6999                         local_irq_restore(flags);
7000
7001                         flush_dcache_page(bvec->bv_page);
7002                         if (csum != csums[index]) {
7003                                 btrfs_err(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
7004                                           btrfs_ino(inode), start, csum,
7005                                           csums[index]);
7006                                 err = -EIO;
7007                         }
7008                 }
7009
7010                 start += bvec->bv_len;
7011                 bvec++;
7012                 index++;
7013         } while (bvec <= bvec_end);
7014
7015         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
7016                       dip->logical_offset + dip->bytes - 1);
7017         dio_bio = dip->dio_bio;
7018
7019         kfree(dip);
7020
7021         /* If we had a csum failure make sure to clear the uptodate flag */
7022         if (err)
7023                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7024         dio_end_io(dio_bio, err);
7025         bio_put(bio);
7026 }
7027
7028 static void btrfs_endio_direct_write(struct bio *bio, int err)
7029 {
7030         struct btrfs_dio_private *dip = bio->bi_private;
7031         struct inode *inode = dip->inode;
7032         struct btrfs_root *root = BTRFS_I(inode)->root;
7033         struct btrfs_ordered_extent *ordered = NULL;
7034         u64 ordered_offset = dip->logical_offset;
7035         u64 ordered_bytes = dip->bytes;
7036         struct bio *dio_bio;
7037         int ret;
7038
7039         if (err)
7040                 goto out_done;
7041 again:
7042         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
7043                                                    &ordered_offset,
7044                                                    ordered_bytes, !err);
7045         if (!ret)
7046                 goto out_test;
7047
7048         btrfs_init_work(&ordered->work, finish_ordered_fn, NULL, NULL);
7049         btrfs_queue_work(root->fs_info->endio_write_workers,
7050                          &ordered->work);
7051 out_test:
7052         /*
7053          * our bio might span multiple ordered extents.  If we haven't
7054          * completed the accounting for the whole dio, go back and try again
7055          */
7056         if (ordered_offset < dip->logical_offset + dip->bytes) {
7057                 ordered_bytes = dip->logical_offset + dip->bytes -
7058                         ordered_offset;
7059                 ordered = NULL;
7060                 goto again;
7061         }
7062 out_done:
7063         dio_bio = dip->dio_bio;
7064
7065         kfree(dip);
7066
7067         /* If we had an error make sure to clear the uptodate flag */
7068         if (err)
7069                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7070         dio_end_io(dio_bio, err);
7071         bio_put(bio);
7072 }
7073
7074 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
7075                                     struct bio *bio, int mirror_num,
7076                                     unsigned long bio_flags, u64 offset)
7077 {
7078         int ret;
7079         struct btrfs_root *root = BTRFS_I(inode)->root;
7080         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
7081         BUG_ON(ret); /* -ENOMEM */
7082         return 0;
7083 }
7084
7085 static void btrfs_end_dio_bio(struct bio *bio, int err)
7086 {
7087         struct btrfs_dio_private *dip = bio->bi_private;
7088
7089         if (err) {
7090                 btrfs_err(BTRFS_I(dip->inode)->root->fs_info,
7091                           "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
7092                       btrfs_ino(dip->inode), bio->bi_rw,
7093                       (unsigned long long)bio->bi_sector, bio->bi_size, err);
7094                 dip->errors = 1;
7095
7096                 /*
7097                  * before atomic variable goto zero, we must make sure
7098                  * dip->errors is perceived to be set.
7099                  */
7100                 smp_mb__before_atomic_dec();
7101         }
7102
7103         /* if there are more bios still pending for this dio, just exit */
7104         if (!atomic_dec_and_test(&dip->pending_bios))
7105                 goto out;
7106
7107         if (dip->errors) {
7108                 bio_io_error(dip->orig_bio);
7109         } else {
7110                 set_bit(BIO_UPTODATE, &dip->dio_bio->bi_flags);
7111                 bio_endio(dip->orig_bio, 0);
7112         }
7113 out:
7114         bio_put(bio);
7115 }
7116
7117 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
7118                                        u64 first_sector, gfp_t gfp_flags)
7119 {
7120         int nr_vecs = bio_get_nr_vecs(bdev);
7121         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
7122 }
7123
7124 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
7125                                          int rw, u64 file_offset, int skip_sum,
7126                                          int async_submit)
7127 {
7128         struct btrfs_dio_private *dip = bio->bi_private;
7129         int write = rw & REQ_WRITE;
7130         struct btrfs_root *root = BTRFS_I(inode)->root;
7131         int ret;
7132
7133         if (async_submit)
7134                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7135
7136         bio_get(bio);
7137
7138         if (!write) {
7139                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
7140                 if (ret)
7141                         goto err;
7142         }
7143
7144         if (skip_sum)
7145                 goto map;
7146
7147         if (write && async_submit) {
7148                 ret = btrfs_wq_submit_bio(root->fs_info,
7149                                    inode, rw, bio, 0, 0,
7150                                    file_offset,
7151                                    __btrfs_submit_bio_start_direct_io,
7152                                    __btrfs_submit_bio_done);
7153                 goto err;
7154         } else if (write) {
7155                 /*
7156                  * If we aren't doing async submit, calculate the csum of the
7157                  * bio now.
7158                  */
7159                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
7160                 if (ret)
7161                         goto err;
7162         } else if (!skip_sum) {
7163                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip, bio,
7164                                                 file_offset);
7165                 if (ret)
7166                         goto err;
7167         }
7168
7169 map:
7170         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
7171 err:
7172         bio_put(bio);
7173         return ret;
7174 }
7175
7176 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
7177                                     int skip_sum)
7178 {
7179         struct inode *inode = dip->inode;
7180         struct btrfs_root *root = BTRFS_I(inode)->root;
7181         struct bio *bio;
7182         struct bio *orig_bio = dip->orig_bio;
7183         struct bio_vec *bvec = orig_bio->bi_io_vec;
7184         u64 start_sector = orig_bio->bi_sector;
7185         u64 file_offset = dip->logical_offset;
7186         u64 submit_len = 0;
7187         u64 map_length;
7188         int nr_pages = 0;
7189         int ret = 0;
7190         int async_submit = 0;
7191
7192         map_length = orig_bio->bi_size;
7193         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
7194                               &map_length, NULL, 0);
7195         if (ret) {
7196                 bio_put(orig_bio);
7197                 return -EIO;
7198         }
7199
7200         if (map_length >= orig_bio->bi_size) {
7201                 bio = orig_bio;
7202                 goto submit;
7203         }
7204
7205         /* async crcs make it difficult to collect full stripe writes. */
7206         if (btrfs_get_alloc_profile(root, 1) &
7207             (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
7208                 async_submit = 0;
7209         else
7210                 async_submit = 1;
7211
7212         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
7213         if (!bio)
7214                 return -ENOMEM;
7215         bio->bi_private = dip;
7216         bio->bi_end_io = btrfs_end_dio_bio;
7217         atomic_inc(&dip->pending_bios);
7218
7219         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
7220                 if (unlikely(map_length < submit_len + bvec->bv_len ||
7221                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
7222                                  bvec->bv_offset) < bvec->bv_len)) {
7223                         /*
7224                          * inc the count before we submit the bio so
7225                          * we know the end IO handler won't happen before
7226                          * we inc the count. Otherwise, the dip might get freed
7227                          * before we're done setting it up
7228                          */
7229                         atomic_inc(&dip->pending_bios);
7230                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
7231                                                      file_offset, skip_sum,
7232                                                      async_submit);
7233                         if (ret) {
7234                                 bio_put(bio);
7235                                 atomic_dec(&dip->pending_bios);
7236                                 goto out_err;
7237                         }
7238
7239                         start_sector += submit_len >> 9;
7240                         file_offset += submit_len;
7241
7242                         submit_len = 0;
7243                         nr_pages = 0;
7244
7245                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
7246                                                   start_sector, GFP_NOFS);
7247                         if (!bio)
7248                                 goto out_err;
7249                         bio->bi_private = dip;
7250                         bio->bi_end_io = btrfs_end_dio_bio;
7251
7252                         map_length = orig_bio->bi_size;
7253                         ret = btrfs_map_block(root->fs_info, rw,
7254                                               start_sector << 9,
7255                                               &map_length, NULL, 0);
7256                         if (ret) {
7257                                 bio_put(bio);
7258                                 goto out_err;
7259                         }
7260                 } else {
7261                         submit_len += bvec->bv_len;
7262                         nr_pages++;
7263                         bvec++;
7264                 }
7265         }
7266
7267 submit:
7268         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
7269                                      async_submit);
7270         if (!ret)
7271                 return 0;
7272
7273         bio_put(bio);
7274 out_err:
7275         dip->errors = 1;
7276         /*
7277          * before atomic variable goto zero, we must
7278          * make sure dip->errors is perceived to be set.
7279          */
7280         smp_mb__before_atomic_dec();
7281         if (atomic_dec_and_test(&dip->pending_bios))
7282                 bio_io_error(dip->orig_bio);
7283
7284         /* bio_end_io() will handle error, so we needn't return it */
7285         return 0;
7286 }
7287
7288 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
7289                                 struct inode *inode, loff_t file_offset)
7290 {
7291         struct btrfs_root *root = BTRFS_I(inode)->root;
7292         struct btrfs_dio_private *dip;
7293         struct bio *io_bio;
7294         int skip_sum;
7295         int sum_len;
7296         int write = rw & REQ_WRITE;
7297         int ret = 0;
7298         u16 csum_size;
7299
7300         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7301
7302         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
7303         if (!io_bio) {
7304                 ret = -ENOMEM;
7305                 goto free_ordered;
7306         }
7307
7308         if (!skip_sum && !write) {
7309                 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
7310                 sum_len = dio_bio->bi_size >> inode->i_sb->s_blocksize_bits;
7311                 sum_len *= csum_size;
7312         } else {
7313                 sum_len = 0;
7314         }
7315
7316         dip = kmalloc(sizeof(*dip) + sum_len, GFP_NOFS);
7317         if (!dip) {
7318                 ret = -ENOMEM;
7319                 goto free_io_bio;
7320         }
7321
7322         dip->private = dio_bio->bi_private;
7323         dip->inode = inode;
7324         dip->logical_offset = file_offset;
7325         dip->bytes = dio_bio->bi_size;
7326         dip->disk_bytenr = (u64)dio_bio->bi_sector << 9;
7327         io_bio->bi_private = dip;
7328         dip->errors = 0;
7329         dip->orig_bio = io_bio;
7330         dip->dio_bio = dio_bio;
7331         atomic_set(&dip->pending_bios, 0);
7332
7333         if (write)
7334                 io_bio->bi_end_io = btrfs_endio_direct_write;
7335         else
7336                 io_bio->bi_end_io = btrfs_endio_direct_read;
7337
7338         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
7339         if (!ret)
7340                 return;
7341
7342 free_io_bio:
7343         bio_put(io_bio);
7344
7345 free_ordered:
7346         /*
7347          * If this is a write, we need to clean up the reserved space and kill
7348          * the ordered extent.
7349          */
7350         if (write) {
7351                 struct btrfs_ordered_extent *ordered;
7352                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
7353                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
7354                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
7355                         btrfs_free_reserved_extent(root, ordered->start,
7356                                                    ordered->disk_len);
7357                 btrfs_put_ordered_extent(ordered);
7358                 btrfs_put_ordered_extent(ordered);
7359         }
7360         bio_endio(dio_bio, ret);
7361 }
7362
7363 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
7364                         const struct iovec *iov, loff_t offset,
7365                         unsigned long nr_segs)
7366 {
7367         int seg;
7368         int i;
7369         size_t size;
7370         unsigned long addr;
7371         unsigned blocksize_mask = root->sectorsize - 1;
7372         ssize_t retval = -EINVAL;
7373         loff_t end = offset;
7374
7375         if (offset & blocksize_mask)
7376                 goto out;
7377
7378         /* Check the memory alignment.  Blocks cannot straddle pages */
7379         for (seg = 0; seg < nr_segs; seg++) {
7380                 addr = (unsigned long)iov[seg].iov_base;
7381                 size = iov[seg].iov_len;
7382                 end += size;
7383                 if ((addr & blocksize_mask) || (size & blocksize_mask))
7384                         goto out;
7385
7386                 /* If this is a write we don't need to check anymore */
7387                 if (rw & WRITE)
7388                         continue;
7389
7390                 /*
7391                  * Check to make sure we don't have duplicate iov_base's in this
7392                  * iovec, if so return EINVAL, otherwise we'll get csum errors
7393                  * when reading back.
7394                  */
7395                 for (i = seg + 1; i < nr_segs; i++) {
7396                         if (iov[seg].iov_base == iov[i].iov_base)
7397                                 goto out;
7398                 }
7399         }
7400         retval = 0;
7401 out:
7402         return retval;
7403 }
7404
7405 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
7406                         const struct iovec *iov, loff_t offset,
7407                         unsigned long nr_segs)
7408 {
7409         struct file *file = iocb->ki_filp;
7410         struct inode *inode = file->f_mapping->host;
7411         size_t count = 0;
7412         int flags = 0;
7413         bool wakeup = true;
7414         bool relock = false;
7415         ssize_t ret;
7416
7417         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iov,
7418                             offset, nr_segs))
7419                 return 0;
7420
7421         atomic_inc(&inode->i_dio_count);
7422         smp_mb__after_atomic_inc();
7423
7424         /*
7425          * The generic stuff only does filemap_write_and_wait_range, which
7426          * isn't enough if we've written compressed pages to this area, so
7427          * we need to flush the dirty pages again to make absolutely sure
7428          * that any outstanding dirty pages are on disk.
7429          */
7430         count = iov_length(iov, nr_segs);
7431         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
7432                      &BTRFS_I(inode)->runtime_flags))
7433                 filemap_fdatawrite_range(inode->i_mapping, offset, count);
7434
7435         if (rw & WRITE) {
7436                 /*
7437                  * If the write DIO is beyond the EOF, we need update
7438                  * the isize, but it is protected by i_mutex. So we can
7439                  * not unlock the i_mutex at this case.
7440                  */
7441                 if (offset + count <= inode->i_size) {
7442                         mutex_unlock(&inode->i_mutex);
7443                         relock = true;
7444                 }
7445                 ret = btrfs_delalloc_reserve_space(inode, count);
7446                 if (ret)
7447                         goto out;
7448         } else if (unlikely(test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
7449                                      &BTRFS_I(inode)->runtime_flags))) {
7450                 inode_dio_done(inode);
7451                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
7452                 wakeup = false;
7453         }
7454
7455         ret = __blockdev_direct_IO(rw, iocb, inode,
7456                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
7457                         iov, offset, nr_segs, btrfs_get_blocks_direct, NULL,
7458                         btrfs_submit_direct, flags);
7459         if (rw & WRITE) {
7460                 if (ret < 0 && ret != -EIOCBQUEUED)
7461                         btrfs_delalloc_release_space(inode, count);
7462                 else if (ret >= 0 && (size_t)ret < count)
7463                         btrfs_delalloc_release_space(inode,
7464                                                      count - (size_t)ret);
7465                 else
7466                         btrfs_delalloc_release_metadata(inode, 0);
7467         }
7468 out:
7469         if (wakeup)
7470                 inode_dio_done(inode);
7471         if (relock)
7472                 mutex_lock(&inode->i_mutex);
7473
7474         return ret;
7475 }
7476
7477 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
7478
7479 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
7480                 __u64 start, __u64 len)
7481 {
7482         int     ret;
7483
7484         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
7485         if (ret)
7486                 return ret;
7487
7488         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
7489 }
7490
7491 int btrfs_readpage(struct file *file, struct page *page)
7492 {
7493         struct extent_io_tree *tree;
7494         tree = &BTRFS_I(page->mapping->host)->io_tree;
7495         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
7496 }
7497
7498 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
7499 {
7500         struct extent_io_tree *tree;
7501
7502
7503         if (current->flags & PF_MEMALLOC) {
7504                 redirty_page_for_writepage(wbc, page);
7505                 unlock_page(page);
7506                 return 0;
7507         }
7508         tree = &BTRFS_I(page->mapping->host)->io_tree;
7509         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
7510 }
7511
7512 static int btrfs_writepages(struct address_space *mapping,
7513                             struct writeback_control *wbc)
7514 {
7515         struct extent_io_tree *tree;
7516
7517         tree = &BTRFS_I(mapping->host)->io_tree;
7518         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
7519 }
7520
7521 static int
7522 btrfs_readpages(struct file *file, struct address_space *mapping,
7523                 struct list_head *pages, unsigned nr_pages)
7524 {
7525         struct extent_io_tree *tree;
7526         tree = &BTRFS_I(mapping->host)->io_tree;
7527         return extent_readpages(tree, mapping, pages, nr_pages,
7528                                 btrfs_get_extent);
7529 }
7530 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7531 {
7532         struct extent_io_tree *tree;
7533         struct extent_map_tree *map;
7534         int ret;
7535
7536         tree = &BTRFS_I(page->mapping->host)->io_tree;
7537         map = &BTRFS_I(page->mapping->host)->extent_tree;
7538         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
7539         if (ret == 1) {
7540                 ClearPagePrivate(page);
7541                 set_page_private(page, 0);
7542                 page_cache_release(page);
7543         }
7544         return ret;
7545 }
7546
7547 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7548 {
7549         if (PageWriteback(page) || PageDirty(page))
7550                 return 0;
7551         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
7552 }
7553
7554 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
7555                                  unsigned int length)
7556 {
7557         struct inode *inode = page->mapping->host;
7558         struct extent_io_tree *tree;
7559         struct btrfs_ordered_extent *ordered;
7560         struct extent_state *cached_state = NULL;
7561         u64 page_start = page_offset(page);
7562         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
7563         int inode_evicting = inode->i_state & I_FREEING;
7564
7565         /*
7566          * we have the page locked, so new writeback can't start,
7567          * and the dirty bit won't be cleared while we are here.
7568          *
7569          * Wait for IO on this page so that we can safely clear
7570          * the PagePrivate2 bit and do ordered accounting
7571          */
7572         wait_on_page_writeback(page);
7573
7574         tree = &BTRFS_I(inode)->io_tree;
7575         if (offset) {
7576                 btrfs_releasepage(page, GFP_NOFS);
7577                 return;
7578         }
7579
7580         if (!inode_evicting)
7581                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
7582         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7583         if (ordered) {
7584                 /*
7585                  * IO on this page will never be started, so we need
7586                  * to account for any ordered extents now
7587                  */
7588                 if (!inode_evicting)
7589                         clear_extent_bit(tree, page_start, page_end,
7590                                          EXTENT_DIRTY | EXTENT_DELALLOC |
7591                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
7592                                          EXTENT_DEFRAG, 1, 0, &cached_state,
7593                                          GFP_NOFS);
7594                 /*
7595                  * whoever cleared the private bit is responsible
7596                  * for the finish_ordered_io
7597                  */
7598                 if (TestClearPagePrivate2(page)) {
7599                         struct btrfs_ordered_inode_tree *tree;
7600                         u64 new_len;
7601
7602                         tree = &BTRFS_I(inode)->ordered_tree;
7603
7604                         spin_lock_irq(&tree->lock);
7605                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
7606                         new_len = page_start - ordered->file_offset;
7607                         if (new_len < ordered->truncated_len)
7608                                 ordered->truncated_len = new_len;
7609                         spin_unlock_irq(&tree->lock);
7610
7611                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
7612                                                            page_start,
7613                                                            PAGE_CACHE_SIZE, 1))
7614                                 btrfs_finish_ordered_io(ordered);
7615                 }
7616                 btrfs_put_ordered_extent(ordered);
7617                 if (!inode_evicting) {
7618                         cached_state = NULL;
7619                         lock_extent_bits(tree, page_start, page_end, 0,
7620                                          &cached_state);
7621                 }
7622         }
7623
7624         if (!inode_evicting) {
7625                 clear_extent_bit(tree, page_start, page_end,
7626                                  EXTENT_LOCKED | EXTENT_DIRTY |
7627                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
7628                                  EXTENT_DEFRAG, 1, 1,
7629                                  &cached_state, GFP_NOFS);
7630
7631                 __btrfs_releasepage(page, GFP_NOFS);
7632         }
7633
7634         ClearPageChecked(page);
7635         if (PagePrivate(page)) {
7636                 ClearPagePrivate(page);
7637                 set_page_private(page, 0);
7638                 page_cache_release(page);
7639         }
7640 }
7641
7642 /*
7643  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
7644  * called from a page fault handler when a page is first dirtied. Hence we must
7645  * be careful to check for EOF conditions here. We set the page up correctly
7646  * for a written page which means we get ENOSPC checking when writing into
7647  * holes and correct delalloc and unwritten extent mapping on filesystems that
7648  * support these features.
7649  *
7650  * We are not allowed to take the i_mutex here so we have to play games to
7651  * protect against truncate races as the page could now be beyond EOF.  Because
7652  * vmtruncate() writes the inode size before removing pages, once we have the
7653  * page lock we can determine safely if the page is beyond EOF. If it is not
7654  * beyond EOF, then the page is guaranteed safe against truncation until we
7655  * unlock the page.
7656  */
7657 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
7658 {
7659         struct page *page = vmf->page;
7660         struct inode *inode = file_inode(vma->vm_file);
7661         struct btrfs_root *root = BTRFS_I(inode)->root;
7662         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7663         struct btrfs_ordered_extent *ordered;
7664         struct extent_state *cached_state = NULL;
7665         char *kaddr;
7666         unsigned long zero_start;
7667         loff_t size;
7668         int ret;
7669         int reserved = 0;
7670         u64 page_start;
7671         u64 page_end;
7672
7673         sb_start_pagefault(inode->i_sb);
7674         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
7675         if (!ret) {
7676                 ret = file_update_time(vma->vm_file);
7677                 reserved = 1;
7678         }
7679         if (ret) {
7680                 if (ret == -ENOMEM)
7681                         ret = VM_FAULT_OOM;
7682                 else /* -ENOSPC, -EIO, etc */
7683                         ret = VM_FAULT_SIGBUS;
7684                 if (reserved)
7685                         goto out;
7686                 goto out_noreserve;
7687         }
7688
7689         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
7690 again:
7691         lock_page(page);
7692         size = i_size_read(inode);
7693         page_start = page_offset(page);
7694         page_end = page_start + PAGE_CACHE_SIZE - 1;
7695
7696         if ((page->mapping != inode->i_mapping) ||
7697             (page_start >= size)) {
7698                 /* page got truncated out from underneath us */
7699                 goto out_unlock;
7700         }
7701         wait_on_page_writeback(page);
7702
7703         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
7704         set_page_extent_mapped(page);
7705
7706         /*
7707          * we can't set the delalloc bits if there are pending ordered
7708          * extents.  Drop our locks and wait for them to finish
7709          */
7710         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7711         if (ordered) {
7712                 unlock_extent_cached(io_tree, page_start, page_end,
7713                                      &cached_state, GFP_NOFS);
7714                 unlock_page(page);
7715                 btrfs_start_ordered_extent(inode, ordered, 1);
7716                 btrfs_put_ordered_extent(ordered);
7717                 goto again;
7718         }
7719
7720         /*
7721          * XXX - page_mkwrite gets called every time the page is dirtied, even
7722          * if it was already dirty, so for space accounting reasons we need to
7723          * clear any delalloc bits for the range we are fixing to save.  There
7724          * is probably a better way to do this, but for now keep consistent with
7725          * prepare_pages in the normal write path.
7726          */
7727         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
7728                           EXTENT_DIRTY | EXTENT_DELALLOC |
7729                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
7730                           0, 0, &cached_state, GFP_NOFS);
7731
7732         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
7733                                         &cached_state);
7734         if (ret) {
7735                 unlock_extent_cached(io_tree, page_start, page_end,
7736                                      &cached_state, GFP_NOFS);
7737                 ret = VM_FAULT_SIGBUS;
7738                 goto out_unlock;
7739         }
7740         ret = 0;
7741
7742         /* page is wholly or partially inside EOF */
7743         if (page_start + PAGE_CACHE_SIZE > size)
7744                 zero_start = size & ~PAGE_CACHE_MASK;
7745         else
7746                 zero_start = PAGE_CACHE_SIZE;
7747
7748         if (zero_start != PAGE_CACHE_SIZE) {
7749                 kaddr = kmap(page);
7750                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
7751                 flush_dcache_page(page);
7752                 kunmap(page);
7753         }
7754         ClearPageChecked(page);
7755         set_page_dirty(page);
7756         SetPageUptodate(page);
7757
7758         BTRFS_I(inode)->last_trans = root->fs_info->generation;
7759         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
7760         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
7761
7762         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
7763
7764 out_unlock:
7765         if (!ret) {
7766                 sb_end_pagefault(inode->i_sb);
7767                 return VM_FAULT_LOCKED;
7768         }
7769         unlock_page(page);
7770 out:
7771         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
7772 out_noreserve:
7773         sb_end_pagefault(inode->i_sb);
7774         return ret;
7775 }
7776
7777 static int btrfs_truncate(struct inode *inode)
7778 {
7779         struct btrfs_root *root = BTRFS_I(inode)->root;
7780         struct btrfs_block_rsv *rsv;
7781         int ret = 0;
7782         int err = 0;
7783         struct btrfs_trans_handle *trans;
7784         u64 mask = root->sectorsize - 1;
7785         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
7786
7787         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
7788                                        (u64)-1);
7789         if (ret)
7790                 return ret;
7791
7792         /*
7793          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
7794          * 3 things going on here
7795          *
7796          * 1) We need to reserve space for our orphan item and the space to
7797          * delete our orphan item.  Lord knows we don't want to have a dangling
7798          * orphan item because we didn't reserve space to remove it.
7799          *
7800          * 2) We need to reserve space to update our inode.
7801          *
7802          * 3) We need to have something to cache all the space that is going to
7803          * be free'd up by the truncate operation, but also have some slack
7804          * space reserved in case it uses space during the truncate (thank you
7805          * very much snapshotting).
7806          *
7807          * And we need these to all be seperate.  The fact is we can use alot of
7808          * space doing the truncate, and we have no earthly idea how much space
7809          * we will use, so we need the truncate reservation to be seperate so it
7810          * doesn't end up using space reserved for updating the inode or
7811          * removing the orphan item.  We also need to be able to stop the
7812          * transaction and start a new one, which means we need to be able to
7813          * update the inode several times, and we have no idea of knowing how
7814          * many times that will be, so we can't just reserve 1 item for the
7815          * entirety of the opration, so that has to be done seperately as well.
7816          * Then there is the orphan item, which does indeed need to be held on
7817          * to for the whole operation, and we need nobody to touch this reserved
7818          * space except the orphan code.
7819          *
7820          * So that leaves us with
7821          *
7822          * 1) root->orphan_block_rsv - for the orphan deletion.
7823          * 2) rsv - for the truncate reservation, which we will steal from the
7824          * transaction reservation.
7825          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
7826          * updating the inode.
7827          */
7828         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
7829         if (!rsv)
7830                 return -ENOMEM;
7831         rsv->size = min_size;
7832         rsv->failfast = 1;
7833
7834         /*
7835          * 1 for the truncate slack space
7836          * 1 for updating the inode.
7837          */
7838         trans = btrfs_start_transaction(root, 2);
7839         if (IS_ERR(trans)) {
7840                 err = PTR_ERR(trans);
7841                 goto out;
7842         }
7843
7844         /* Migrate the slack space for the truncate to our reserve */
7845         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
7846                                       min_size);
7847         BUG_ON(ret);
7848
7849         /*
7850          * setattr is responsible for setting the ordered_data_close flag,
7851          * but that is only tested during the last file release.  That
7852          * could happen well after the next commit, leaving a great big
7853          * window where new writes may get lost if someone chooses to write
7854          * to this file after truncating to zero
7855          *
7856          * The inode doesn't have any dirty data here, and so if we commit
7857          * this is a noop.  If someone immediately starts writing to the inode
7858          * it is very likely we'll catch some of their writes in this
7859          * transaction, and the commit will find this file on the ordered
7860          * data list with good things to send down.
7861          *
7862          * This is a best effort solution, there is still a window where
7863          * using truncate to replace the contents of the file will
7864          * end up with a zero length file after a crash.
7865          */
7866         if (inode->i_size == 0 && test_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
7867                                            &BTRFS_I(inode)->runtime_flags))
7868                 btrfs_add_ordered_operation(trans, root, inode);
7869
7870         /*
7871          * So if we truncate and then write and fsync we normally would just
7872          * write the extents that changed, which is a problem if we need to
7873          * first truncate that entire inode.  So set this flag so we write out
7874          * all of the extents in the inode to the sync log so we're completely
7875          * safe.
7876          */
7877         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
7878         trans->block_rsv = rsv;
7879
7880         while (1) {
7881                 ret = btrfs_truncate_inode_items(trans, root, inode,
7882                                                  inode->i_size,
7883                                                  BTRFS_EXTENT_DATA_KEY);
7884                 if (ret != -ENOSPC) {
7885                         err = ret;
7886                         break;
7887                 }
7888
7889                 trans->block_rsv = &root->fs_info->trans_block_rsv;
7890                 ret = btrfs_update_inode(trans, root, inode);
7891                 if (ret) {
7892                         err = ret;
7893                         break;
7894                 }
7895
7896                 btrfs_end_transaction(trans, root);
7897                 btrfs_btree_balance_dirty(root);
7898
7899                 trans = btrfs_start_transaction(root, 2);
7900                 if (IS_ERR(trans)) {
7901                         ret = err = PTR_ERR(trans);
7902                         trans = NULL;
7903                         break;
7904                 }
7905
7906                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
7907                                               rsv, min_size);
7908                 BUG_ON(ret);    /* shouldn't happen */
7909                 trans->block_rsv = rsv;
7910         }
7911
7912         if (ret == 0 && inode->i_nlink > 0) {
7913                 trans->block_rsv = root->orphan_block_rsv;
7914                 ret = btrfs_orphan_del(trans, inode);
7915                 if (ret)
7916                         err = ret;
7917         }
7918
7919         if (trans) {
7920                 trans->block_rsv = &root->fs_info->trans_block_rsv;
7921                 ret = btrfs_update_inode(trans, root, inode);
7922                 if (ret && !err)
7923                         err = ret;
7924
7925                 ret = btrfs_end_transaction(trans, root);
7926                 btrfs_btree_balance_dirty(root);
7927         }
7928
7929 out:
7930         btrfs_free_block_rsv(root, rsv);
7931
7932         if (ret && !err)
7933                 err = ret;
7934
7935         return err;
7936 }
7937
7938 /*
7939  * create a new subvolume directory/inode (helper for the ioctl).
7940  */
7941 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
7942                              struct btrfs_root *new_root,
7943                              struct btrfs_root *parent_root,
7944                              u64 new_dirid)
7945 {
7946         struct inode *inode;
7947         int err;
7948         u64 index = 0;
7949
7950         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
7951                                 new_dirid, new_dirid,
7952                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
7953                                 &index);
7954         if (IS_ERR(inode))
7955                 return PTR_ERR(inode);
7956         inode->i_op = &btrfs_dir_inode_operations;
7957         inode->i_fop = &btrfs_dir_file_operations;
7958
7959         set_nlink(inode, 1);
7960         btrfs_i_size_write(inode, 0);
7961
7962         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
7963         if (err)
7964                 btrfs_err(new_root->fs_info,
7965                           "error inheriting subvolume %llu properties: %d\n",
7966                           new_root->root_key.objectid, err);
7967
7968         err = btrfs_update_inode(trans, new_root, inode);
7969
7970         iput(inode);
7971         return err;
7972 }
7973
7974 struct inode *btrfs_alloc_inode(struct super_block *sb)
7975 {
7976         struct btrfs_inode *ei;
7977         struct inode *inode;
7978
7979         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
7980         if (!ei)
7981                 return NULL;
7982
7983         ei->root = NULL;
7984         ei->generation = 0;
7985         ei->last_trans = 0;
7986         ei->last_sub_trans = 0;
7987         ei->logged_trans = 0;
7988         ei->delalloc_bytes = 0;
7989         ei->disk_i_size = 0;
7990         ei->flags = 0;
7991         ei->csum_bytes = 0;
7992         ei->index_cnt = (u64)-1;
7993         ei->dir_index = 0;
7994         ei->last_unlink_trans = 0;
7995         ei->last_log_commit = 0;
7996
7997         spin_lock_init(&ei->lock);
7998         ei->outstanding_extents = 0;
7999         ei->reserved_extents = 0;
8000
8001         ei->runtime_flags = 0;
8002         ei->force_compress = BTRFS_COMPRESS_NONE;
8003
8004         ei->delayed_node = NULL;
8005
8006         inode = &ei->vfs_inode;
8007         extent_map_tree_init(&ei->extent_tree);
8008         extent_io_tree_init(&ei->io_tree, &inode->i_data);
8009         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
8010         ei->io_tree.track_uptodate = 1;
8011         ei->io_failure_tree.track_uptodate = 1;
8012         atomic_set(&ei->sync_writers, 0);
8013         mutex_init(&ei->log_mutex);
8014         mutex_init(&ei->delalloc_mutex);
8015         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
8016         INIT_LIST_HEAD(&ei->delalloc_inodes);
8017         INIT_LIST_HEAD(&ei->ordered_operations);
8018         RB_CLEAR_NODE(&ei->rb_node);
8019
8020         return inode;
8021 }
8022
8023 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8024 void btrfs_test_destroy_inode(struct inode *inode)
8025 {
8026         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8027         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8028 }
8029 #endif
8030
8031 static void btrfs_i_callback(struct rcu_head *head)
8032 {
8033         struct inode *inode = container_of(head, struct inode, i_rcu);
8034         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8035 }
8036
8037 void btrfs_destroy_inode(struct inode *inode)
8038 {
8039         struct btrfs_ordered_extent *ordered;
8040         struct btrfs_root *root = BTRFS_I(inode)->root;
8041
8042         WARN_ON(!hlist_empty(&inode->i_dentry));
8043         WARN_ON(inode->i_data.nrpages);
8044         WARN_ON(BTRFS_I(inode)->outstanding_extents);
8045         WARN_ON(BTRFS_I(inode)->reserved_extents);
8046         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
8047         WARN_ON(BTRFS_I(inode)->csum_bytes);
8048
8049         /*
8050          * This can happen where we create an inode, but somebody else also
8051          * created the same inode and we need to destroy the one we already
8052          * created.
8053          */
8054         if (!root)
8055                 goto free;
8056
8057         /*
8058          * Make sure we're properly removed from the ordered operation
8059          * lists.
8060          */
8061         smp_mb();
8062         if (!list_empty(&BTRFS_I(inode)->ordered_operations)) {
8063                 spin_lock(&root->fs_info->ordered_root_lock);
8064                 list_del_init(&BTRFS_I(inode)->ordered_operations);
8065                 spin_unlock(&root->fs_info->ordered_root_lock);
8066         }
8067
8068         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
8069                      &BTRFS_I(inode)->runtime_flags)) {
8070                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
8071                         btrfs_ino(inode));
8072                 atomic_dec(&root->orphan_inodes);
8073         }
8074
8075         while (1) {
8076                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
8077                 if (!ordered)
8078                         break;
8079                 else {
8080                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
8081                                 ordered->file_offset, ordered->len);
8082                         btrfs_remove_ordered_extent(inode, ordered);
8083                         btrfs_put_ordered_extent(ordered);
8084                         btrfs_put_ordered_extent(ordered);
8085                 }
8086         }
8087         inode_tree_del(inode);
8088         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8089 free:
8090         call_rcu(&inode->i_rcu, btrfs_i_callback);
8091 }
8092
8093 int btrfs_drop_inode(struct inode *inode)
8094 {
8095         struct btrfs_root *root = BTRFS_I(inode)->root;
8096
8097         if (root == NULL)
8098                 return 1;
8099
8100         /* the snap/subvol tree is on deleting */
8101         if (btrfs_root_refs(&root->root_item) == 0)
8102                 return 1;
8103         else
8104                 return generic_drop_inode(inode);
8105 }
8106
8107 static void init_once(void *foo)
8108 {
8109         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8110
8111         inode_init_once(&ei->vfs_inode);
8112 }
8113
8114 void btrfs_destroy_cachep(void)
8115 {
8116         /*
8117          * Make sure all delayed rcu free inodes are flushed before we
8118          * destroy cache.
8119          */
8120         rcu_barrier();
8121         if (btrfs_inode_cachep)
8122                 kmem_cache_destroy(btrfs_inode_cachep);
8123         if (btrfs_trans_handle_cachep)
8124                 kmem_cache_destroy(btrfs_trans_handle_cachep);
8125         if (btrfs_transaction_cachep)
8126                 kmem_cache_destroy(btrfs_transaction_cachep);
8127         if (btrfs_path_cachep)
8128                 kmem_cache_destroy(btrfs_path_cachep);
8129         if (btrfs_free_space_cachep)
8130                 kmem_cache_destroy(btrfs_free_space_cachep);
8131         if (btrfs_delalloc_work_cachep)
8132                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
8133 }
8134
8135 int btrfs_init_cachep(void)
8136 {
8137         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8138                         sizeof(struct btrfs_inode), 0,
8139                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
8140         if (!btrfs_inode_cachep)
8141                 goto fail;
8142
8143         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8144                         sizeof(struct btrfs_trans_handle), 0,
8145                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8146         if (!btrfs_trans_handle_cachep)
8147                 goto fail;
8148
8149         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
8150                         sizeof(struct btrfs_transaction), 0,
8151                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8152         if (!btrfs_transaction_cachep)
8153                 goto fail;
8154
8155         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8156                         sizeof(struct btrfs_path), 0,
8157                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8158         if (!btrfs_path_cachep)
8159                 goto fail;
8160
8161         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8162                         sizeof(struct btrfs_free_space), 0,
8163                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8164         if (!btrfs_free_space_cachep)
8165                 goto fail;
8166
8167         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
8168                         sizeof(struct btrfs_delalloc_work), 0,
8169                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
8170                         NULL);
8171         if (!btrfs_delalloc_work_cachep)
8172                 goto fail;
8173
8174         return 0;
8175 fail:
8176         btrfs_destroy_cachep();
8177         return -ENOMEM;
8178 }
8179
8180 static int btrfs_getattr(struct vfsmount *mnt,
8181                          struct dentry *dentry, struct kstat *stat)
8182 {
8183         u64 delalloc_bytes;
8184         struct inode *inode = dentry->d_inode;
8185         u32 blocksize = inode->i_sb->s_blocksize;
8186
8187         generic_fillattr(inode, stat);
8188         stat->dev = BTRFS_I(inode)->root->anon_dev;
8189         stat->blksize = PAGE_CACHE_SIZE;
8190
8191         spin_lock(&BTRFS_I(inode)->lock);
8192         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
8193         spin_unlock(&BTRFS_I(inode)->lock);
8194         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8195                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8196         return 0;
8197 }
8198
8199 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
8200                            struct inode *new_dir, struct dentry *new_dentry)
8201 {
8202         struct btrfs_trans_handle *trans;
8203         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8204         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8205         struct inode *new_inode = new_dentry->d_inode;
8206         struct inode *old_inode = old_dentry->d_inode;
8207         struct timespec ctime = CURRENT_TIME;
8208         u64 index = 0;
8209         u64 root_objectid;
8210         int ret;
8211         u64 old_ino = btrfs_ino(old_inode);
8212
8213         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
8214                 return -EPERM;
8215
8216         /* we only allow rename subvolume link between subvolumes */
8217         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8218                 return -EXDEV;
8219
8220         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
8221             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
8222                 return -ENOTEMPTY;
8223
8224         if (S_ISDIR(old_inode->i_mode) && new_inode &&
8225             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
8226                 return -ENOTEMPTY;
8227
8228
8229         /* check for collisions, even if the  name isn't there */
8230         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
8231                              new_dentry->d_name.name,
8232                              new_dentry->d_name.len);
8233
8234         if (ret) {
8235                 if (ret == -EEXIST) {
8236                         /* we shouldn't get
8237                          * eexist without a new_inode */
8238                         if (WARN_ON(!new_inode)) {
8239                                 return ret;
8240                         }
8241                 } else {
8242                         /* maybe -EOVERFLOW */
8243                         return ret;
8244                 }
8245         }
8246         ret = 0;
8247
8248         /*
8249          * we're using rename to replace one file with another.
8250          * and the replacement file is large.  Start IO on it now so
8251          * we don't add too much work to the end of the transaction
8252          */
8253         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size &&
8254             old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
8255                 filemap_flush(old_inode->i_mapping);
8256
8257         /* close the racy window with snapshot create/destroy ioctl */
8258         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8259                 down_read(&root->fs_info->subvol_sem);
8260         /*
8261          * We want to reserve the absolute worst case amount of items.  So if
8262          * both inodes are subvols and we need to unlink them then that would
8263          * require 4 item modifications, but if they are both normal inodes it
8264          * would require 5 item modifications, so we'll assume their normal
8265          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
8266          * should cover the worst case number of items we'll modify.
8267          */
8268         trans = btrfs_start_transaction(root, 11);
8269         if (IS_ERR(trans)) {
8270                 ret = PTR_ERR(trans);
8271                 goto out_notrans;
8272         }
8273
8274         if (dest != root)
8275                 btrfs_record_root_in_trans(trans, dest);
8276
8277         ret = btrfs_set_inode_index(new_dir, &index);
8278         if (ret)
8279                 goto out_fail;
8280
8281         BTRFS_I(old_inode)->dir_index = 0ULL;
8282         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8283                 /* force full log commit if subvolume involved. */
8284                 root->fs_info->last_trans_log_full_commit = trans->transid;
8285         } else {
8286                 ret = btrfs_insert_inode_ref(trans, dest,
8287                                              new_dentry->d_name.name,
8288                                              new_dentry->d_name.len,
8289                                              old_ino,
8290                                              btrfs_ino(new_dir), index);
8291                 if (ret)
8292                         goto out_fail;
8293                 /*
8294                  * this is an ugly little race, but the rename is required
8295                  * to make sure that if we crash, the inode is either at the
8296                  * old name or the new one.  pinning the log transaction lets
8297                  * us make sure we don't allow a log commit to come in after
8298                  * we unlink the name but before we add the new name back in.
8299                  */
8300                 btrfs_pin_log_trans(root);
8301         }
8302         /*
8303          * make sure the inode gets flushed if it is replacing
8304          * something.
8305          */
8306         if (new_inode && new_inode->i_size && S_ISREG(old_inode->i_mode))
8307                 btrfs_add_ordered_operation(trans, root, old_inode);
8308
8309         inode_inc_iversion(old_dir);
8310         inode_inc_iversion(new_dir);
8311         inode_inc_iversion(old_inode);
8312         old_dir->i_ctime = old_dir->i_mtime = ctime;
8313         new_dir->i_ctime = new_dir->i_mtime = ctime;
8314         old_inode->i_ctime = ctime;
8315
8316         if (old_dentry->d_parent != new_dentry->d_parent)
8317                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
8318
8319         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8320                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
8321                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
8322                                         old_dentry->d_name.name,
8323                                         old_dentry->d_name.len);
8324         } else {
8325                 ret = __btrfs_unlink_inode(trans, root, old_dir,
8326                                         old_dentry->d_inode,
8327                                         old_dentry->d_name.name,
8328                                         old_dentry->d_name.len);
8329                 if (!ret)
8330                         ret = btrfs_update_inode(trans, root, old_inode);
8331         }
8332         if (ret) {
8333                 btrfs_abort_transaction(trans, root, ret);
8334                 goto out_fail;
8335         }
8336
8337         if (new_inode) {
8338                 inode_inc_iversion(new_inode);
8339                 new_inode->i_ctime = CURRENT_TIME;
8340                 if (unlikely(btrfs_ino(new_inode) ==
8341                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
8342                         root_objectid = BTRFS_I(new_inode)->location.objectid;
8343                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
8344                                                 root_objectid,
8345                                                 new_dentry->d_name.name,
8346                                                 new_dentry->d_name.len);
8347                         BUG_ON(new_inode->i_nlink == 0);
8348                 } else {
8349                         ret = btrfs_unlink_inode(trans, dest, new_dir,
8350                                                  new_dentry->d_inode,
8351                                                  new_dentry->d_name.name,
8352                                                  new_dentry->d_name.len);
8353                 }
8354                 if (!ret && new_inode->i_nlink == 0)
8355                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
8356                 if (ret) {
8357                         btrfs_abort_transaction(trans, root, ret);
8358                         goto out_fail;
8359                 }
8360         }
8361
8362         ret = btrfs_add_link(trans, new_dir, old_inode,
8363                              new_dentry->d_name.name,
8364                              new_dentry->d_name.len, 0, index);
8365         if (ret) {
8366                 btrfs_abort_transaction(trans, root, ret);
8367                 goto out_fail;
8368         }
8369
8370         if (old_inode->i_nlink == 1)
8371                 BTRFS_I(old_inode)->dir_index = index;
8372
8373         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
8374                 struct dentry *parent = new_dentry->d_parent;
8375                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
8376                 btrfs_end_log_trans(root);
8377         }
8378 out_fail:
8379         btrfs_end_transaction(trans, root);
8380 out_notrans:
8381         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8382                 up_read(&root->fs_info->subvol_sem);
8383
8384         return ret;
8385 }
8386
8387 static void btrfs_run_delalloc_work(struct btrfs_work *work)
8388 {
8389         struct btrfs_delalloc_work *delalloc_work;
8390         struct inode *inode;
8391
8392         delalloc_work = container_of(work, struct btrfs_delalloc_work,
8393                                      work);
8394         inode = delalloc_work->inode;
8395         if (delalloc_work->wait) {
8396                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
8397         } else {
8398                 filemap_flush(inode->i_mapping);
8399                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8400                              &BTRFS_I(inode)->runtime_flags))
8401                         filemap_flush(inode->i_mapping);
8402         }
8403
8404         if (delalloc_work->delay_iput)
8405                 btrfs_add_delayed_iput(inode);
8406         else
8407                 iput(inode);
8408         complete(&delalloc_work->completion);
8409 }
8410
8411 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
8412                                                     int wait, int delay_iput)
8413 {
8414         struct btrfs_delalloc_work *work;
8415
8416         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
8417         if (!work)
8418                 return NULL;
8419
8420         init_completion(&work->completion);
8421         INIT_LIST_HEAD(&work->list);
8422         work->inode = inode;
8423         work->wait = wait;
8424         work->delay_iput = delay_iput;
8425         btrfs_init_work(&work->work, btrfs_run_delalloc_work, NULL, NULL);
8426
8427         return work;
8428 }
8429
8430 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
8431 {
8432         wait_for_completion(&work->completion);
8433         kmem_cache_free(btrfs_delalloc_work_cachep, work);
8434 }
8435
8436 /*
8437  * some fairly slow code that needs optimization. This walks the list
8438  * of all the inodes with pending delalloc and forces them to disk.
8439  */
8440 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
8441                                    int nr)
8442 {
8443         struct btrfs_inode *binode;
8444         struct inode *inode;
8445         struct btrfs_delalloc_work *work, *next;
8446         struct list_head works;
8447         struct list_head splice;
8448         int ret = 0;
8449
8450         INIT_LIST_HEAD(&works);
8451         INIT_LIST_HEAD(&splice);
8452
8453         mutex_lock(&root->delalloc_mutex);
8454         spin_lock(&root->delalloc_lock);
8455         list_splice_init(&root->delalloc_inodes, &splice);
8456         while (!list_empty(&splice)) {
8457                 binode = list_entry(splice.next, struct btrfs_inode,
8458                                     delalloc_inodes);
8459
8460                 list_move_tail(&binode->delalloc_inodes,
8461                                &root->delalloc_inodes);
8462                 inode = igrab(&binode->vfs_inode);
8463                 if (!inode) {
8464                         cond_resched_lock(&root->delalloc_lock);
8465                         continue;
8466                 }
8467                 spin_unlock(&root->delalloc_lock);
8468
8469                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
8470                 if (unlikely(!work)) {
8471                         if (delay_iput)
8472                                 btrfs_add_delayed_iput(inode);
8473                         else
8474                                 iput(inode);
8475                         ret = -ENOMEM;
8476                         break;
8477                 }
8478                 list_add_tail(&work->list, &works);
8479                 btrfs_queue_work(root->fs_info->flush_workers,
8480                                  &work->work);
8481                 ret++;
8482                 if (nr != -1 && ret >= nr)
8483                         break;
8484                 cond_resched();
8485                 spin_lock(&root->delalloc_lock);
8486         }
8487         spin_unlock(&root->delalloc_lock);
8488
8489         list_for_each_entry_safe(work, next, &works, list) {
8490                 list_del_init(&work->list);
8491                 btrfs_wait_and_free_delalloc_work(work);
8492         }
8493
8494         if (!list_empty_careful(&splice)) {
8495                 spin_lock(&root->delalloc_lock);
8496                 list_splice_tail(&splice, &root->delalloc_inodes);
8497                 spin_unlock(&root->delalloc_lock);
8498         }
8499         mutex_unlock(&root->delalloc_mutex);
8500         return ret;
8501 }
8502
8503 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
8504 {
8505         int ret;
8506
8507         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
8508                 return -EROFS;
8509
8510         ret = __start_delalloc_inodes(root, delay_iput, -1);
8511         if (ret > 0)
8512                 ret = 0;
8513         /*
8514          * the filemap_flush will queue IO into the worker threads, but
8515          * we have to make sure the IO is actually started and that
8516          * ordered extents get created before we return
8517          */
8518         atomic_inc(&root->fs_info->async_submit_draining);
8519         while (atomic_read(&root->fs_info->nr_async_submits) ||
8520               atomic_read(&root->fs_info->async_delalloc_pages)) {
8521                 wait_event(root->fs_info->async_submit_wait,
8522                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
8523                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
8524         }
8525         atomic_dec(&root->fs_info->async_submit_draining);
8526         return ret;
8527 }
8528
8529 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
8530                                int nr)
8531 {
8532         struct btrfs_root *root;
8533         struct list_head splice;
8534         int ret;
8535
8536         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
8537                 return -EROFS;
8538
8539         INIT_LIST_HEAD(&splice);
8540
8541         mutex_lock(&fs_info->delalloc_root_mutex);
8542         spin_lock(&fs_info->delalloc_root_lock);
8543         list_splice_init(&fs_info->delalloc_roots, &splice);
8544         while (!list_empty(&splice) && nr) {
8545                 root = list_first_entry(&splice, struct btrfs_root,
8546                                         delalloc_root);
8547                 root = btrfs_grab_fs_root(root);
8548                 BUG_ON(!root);
8549                 list_move_tail(&root->delalloc_root,
8550                                &fs_info->delalloc_roots);
8551                 spin_unlock(&fs_info->delalloc_root_lock);
8552
8553                 ret = __start_delalloc_inodes(root, delay_iput, nr);
8554                 btrfs_put_fs_root(root);
8555                 if (ret < 0)
8556                         goto out;
8557
8558                 if (nr != -1) {
8559                         nr -= ret;
8560                         WARN_ON(nr < 0);
8561                 }
8562                 spin_lock(&fs_info->delalloc_root_lock);
8563         }
8564         spin_unlock(&fs_info->delalloc_root_lock);
8565
8566         ret = 0;
8567         atomic_inc(&fs_info->async_submit_draining);
8568         while (atomic_read(&fs_info->nr_async_submits) ||
8569               atomic_read(&fs_info->async_delalloc_pages)) {
8570                 wait_event(fs_info->async_submit_wait,
8571                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
8572                     atomic_read(&fs_info->async_delalloc_pages) == 0));
8573         }
8574         atomic_dec(&fs_info->async_submit_draining);
8575 out:
8576         if (!list_empty_careful(&splice)) {
8577                 spin_lock(&fs_info->delalloc_root_lock);
8578                 list_splice_tail(&splice, &fs_info->delalloc_roots);
8579                 spin_unlock(&fs_info->delalloc_root_lock);
8580         }
8581         mutex_unlock(&fs_info->delalloc_root_mutex);
8582         return ret;
8583 }
8584
8585 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
8586                          const char *symname)
8587 {
8588         struct btrfs_trans_handle *trans;
8589         struct btrfs_root *root = BTRFS_I(dir)->root;
8590         struct btrfs_path *path;
8591         struct btrfs_key key;
8592         struct inode *inode = NULL;
8593         int err;
8594         int drop_inode = 0;
8595         u64 objectid;
8596         u64 index = 0;
8597         int name_len;
8598         int datasize;
8599         unsigned long ptr;
8600         struct btrfs_file_extent_item *ei;
8601         struct extent_buffer *leaf;
8602
8603         name_len = strlen(symname);
8604         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
8605                 return -ENAMETOOLONG;
8606
8607         /*
8608          * 2 items for inode item and ref
8609          * 2 items for dir items
8610          * 1 item for xattr if selinux is on
8611          */
8612         trans = btrfs_start_transaction(root, 5);
8613         if (IS_ERR(trans))
8614                 return PTR_ERR(trans);
8615
8616         err = btrfs_find_free_ino(root, &objectid);
8617         if (err)
8618                 goto out_unlock;
8619
8620         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
8621                                 dentry->d_name.len, btrfs_ino(dir), objectid,
8622                                 S_IFLNK|S_IRWXUGO, &index);
8623         if (IS_ERR(inode)) {
8624                 err = PTR_ERR(inode);
8625                 goto out_unlock;
8626         }
8627
8628         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
8629         if (err) {
8630                 drop_inode = 1;
8631                 goto out_unlock;
8632         }
8633
8634         /*
8635         * If the active LSM wants to access the inode during
8636         * d_instantiate it needs these. Smack checks to see
8637         * if the filesystem supports xattrs by looking at the
8638         * ops vector.
8639         */
8640         inode->i_fop = &btrfs_file_operations;
8641         inode->i_op = &btrfs_file_inode_operations;
8642
8643         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
8644         if (err)
8645                 drop_inode = 1;
8646         else {
8647                 inode->i_mapping->a_ops = &btrfs_aops;
8648                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8649                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
8650         }
8651         if (drop_inode)
8652                 goto out_unlock;
8653
8654         path = btrfs_alloc_path();
8655         if (!path) {
8656                 err = -ENOMEM;
8657                 drop_inode = 1;
8658                 goto out_unlock;
8659         }
8660         key.objectid = btrfs_ino(inode);
8661         key.offset = 0;
8662         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
8663         datasize = btrfs_file_extent_calc_inline_size(name_len);
8664         err = btrfs_insert_empty_item(trans, root, path, &key,
8665                                       datasize);
8666         if (err) {
8667                 drop_inode = 1;
8668                 btrfs_free_path(path);
8669                 goto out_unlock;
8670         }
8671         leaf = path->nodes[0];
8672         ei = btrfs_item_ptr(leaf, path->slots[0],
8673                             struct btrfs_file_extent_item);
8674         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
8675         btrfs_set_file_extent_type(leaf, ei,
8676                                    BTRFS_FILE_EXTENT_INLINE);
8677         btrfs_set_file_extent_encryption(leaf, ei, 0);
8678         btrfs_set_file_extent_compression(leaf, ei, 0);
8679         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
8680         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
8681
8682         ptr = btrfs_file_extent_inline_start(ei);
8683         write_extent_buffer(leaf, symname, ptr, name_len);
8684         btrfs_mark_buffer_dirty(leaf);
8685         btrfs_free_path(path);
8686
8687         inode->i_op = &btrfs_symlink_inode_operations;
8688         inode->i_mapping->a_ops = &btrfs_symlink_aops;
8689         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8690         inode_set_bytes(inode, name_len);
8691         btrfs_i_size_write(inode, name_len);
8692         err = btrfs_update_inode(trans, root, inode);
8693         if (err)
8694                 drop_inode = 1;
8695
8696 out_unlock:
8697         if (!err)
8698                 d_instantiate(dentry, inode);
8699         btrfs_end_transaction(trans, root);
8700         if (drop_inode) {
8701                 inode_dec_link_count(inode);
8702                 iput(inode);
8703         }
8704         btrfs_btree_balance_dirty(root);
8705         return err;
8706 }
8707
8708 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
8709                                        u64 start, u64 num_bytes, u64 min_size,
8710                                        loff_t actual_len, u64 *alloc_hint,
8711                                        struct btrfs_trans_handle *trans)
8712 {
8713         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
8714         struct extent_map *em;
8715         struct btrfs_root *root = BTRFS_I(inode)->root;
8716         struct btrfs_key ins;
8717         u64 cur_offset = start;
8718         u64 i_size;
8719         u64 cur_bytes;
8720         int ret = 0;
8721         bool own_trans = true;
8722
8723         if (trans)
8724                 own_trans = false;
8725         while (num_bytes > 0) {
8726                 if (own_trans) {
8727                         trans = btrfs_start_transaction(root, 3);
8728                         if (IS_ERR(trans)) {
8729                                 ret = PTR_ERR(trans);
8730                                 break;
8731                         }
8732                 }
8733
8734                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
8735                 cur_bytes = max(cur_bytes, min_size);
8736                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
8737                                            *alloc_hint, &ins, 1);
8738                 if (ret) {
8739                         if (own_trans)
8740                                 btrfs_end_transaction(trans, root);
8741                         break;
8742                 }
8743
8744                 ret = insert_reserved_file_extent(trans, inode,
8745                                                   cur_offset, ins.objectid,
8746                                                   ins.offset, ins.offset,
8747                                                   ins.offset, 0, 0, 0,
8748                                                   BTRFS_FILE_EXTENT_PREALLOC);
8749                 if (ret) {
8750                         btrfs_free_reserved_extent(root, ins.objectid,
8751                                                    ins.offset);
8752                         btrfs_abort_transaction(trans, root, ret);
8753                         if (own_trans)
8754                                 btrfs_end_transaction(trans, root);
8755                         break;
8756                 }
8757                 btrfs_drop_extent_cache(inode, cur_offset,
8758                                         cur_offset + ins.offset -1, 0);
8759
8760                 em = alloc_extent_map();
8761                 if (!em) {
8762                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
8763                                 &BTRFS_I(inode)->runtime_flags);
8764                         goto next;
8765                 }
8766
8767                 em->start = cur_offset;
8768                 em->orig_start = cur_offset;
8769                 em->len = ins.offset;
8770                 em->block_start = ins.objectid;
8771                 em->block_len = ins.offset;
8772                 em->orig_block_len = ins.offset;
8773                 em->ram_bytes = ins.offset;
8774                 em->bdev = root->fs_info->fs_devices->latest_bdev;
8775                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
8776                 em->generation = trans->transid;
8777
8778                 while (1) {
8779                         write_lock(&em_tree->lock);
8780                         ret = add_extent_mapping(em_tree, em, 1);
8781                         write_unlock(&em_tree->lock);
8782                         if (ret != -EEXIST)
8783                                 break;
8784                         btrfs_drop_extent_cache(inode, cur_offset,
8785                                                 cur_offset + ins.offset - 1,
8786                                                 0);
8787                 }
8788                 free_extent_map(em);
8789 next:
8790                 num_bytes -= ins.offset;
8791                 cur_offset += ins.offset;
8792                 *alloc_hint = ins.objectid + ins.offset;
8793
8794                 inode_inc_iversion(inode);
8795                 inode->i_ctime = CURRENT_TIME;
8796                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
8797                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
8798                     (actual_len > inode->i_size) &&
8799                     (cur_offset > inode->i_size)) {
8800                         if (cur_offset > actual_len)
8801                                 i_size = actual_len;
8802                         else
8803                                 i_size = cur_offset;
8804                         i_size_write(inode, i_size);
8805                         btrfs_ordered_update_i_size(inode, i_size, NULL);
8806                 }
8807
8808                 ret = btrfs_update_inode(trans, root, inode);
8809
8810                 if (ret) {
8811                         btrfs_abort_transaction(trans, root, ret);
8812                         if (own_trans)
8813                                 btrfs_end_transaction(trans, root);
8814                         break;
8815                 }
8816
8817                 if (own_trans)
8818                         btrfs_end_transaction(trans, root);
8819         }
8820         return ret;
8821 }
8822
8823 int btrfs_prealloc_file_range(struct inode *inode, int mode,
8824                               u64 start, u64 num_bytes, u64 min_size,
8825                               loff_t actual_len, u64 *alloc_hint)
8826 {
8827         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8828                                            min_size, actual_len, alloc_hint,
8829                                            NULL);
8830 }
8831
8832 int btrfs_prealloc_file_range_trans(struct inode *inode,
8833                                     struct btrfs_trans_handle *trans, int mode,
8834                                     u64 start, u64 num_bytes, u64 min_size,
8835                                     loff_t actual_len, u64 *alloc_hint)
8836 {
8837         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8838                                            min_size, actual_len, alloc_hint, trans);
8839 }
8840
8841 static int btrfs_set_page_dirty(struct page *page)
8842 {
8843         return __set_page_dirty_nobuffers(page);
8844 }
8845
8846 static int btrfs_permission(struct inode *inode, int mask)
8847 {
8848         struct btrfs_root *root = BTRFS_I(inode)->root;
8849         umode_t mode = inode->i_mode;
8850
8851         if (mask & MAY_WRITE &&
8852             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
8853                 if (btrfs_root_readonly(root))
8854                         return -EROFS;
8855                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
8856                         return -EACCES;
8857         }
8858         return generic_permission(inode, mask);
8859 }
8860
8861 static const struct inode_operations btrfs_dir_inode_operations = {
8862         .getattr        = btrfs_getattr,
8863         .lookup         = btrfs_lookup,
8864         .create         = btrfs_create,
8865         .unlink         = btrfs_unlink,
8866         .link           = btrfs_link,
8867         .mkdir          = btrfs_mkdir,
8868         .rmdir          = btrfs_rmdir,
8869         .rename         = btrfs_rename,
8870         .symlink        = btrfs_symlink,
8871         .setattr        = btrfs_setattr,
8872         .mknod          = btrfs_mknod,
8873         .setxattr       = btrfs_setxattr,
8874         .getxattr       = btrfs_getxattr,
8875         .listxattr      = btrfs_listxattr,
8876         .removexattr    = btrfs_removexattr,
8877         .permission     = btrfs_permission,
8878         .get_acl        = btrfs_get_acl,
8879         .update_time    = btrfs_update_time,
8880 };
8881 static const struct inode_operations btrfs_dir_ro_inode_operations = {
8882         .lookup         = btrfs_lookup,
8883         .permission     = btrfs_permission,
8884         .get_acl        = btrfs_get_acl,
8885         .update_time    = btrfs_update_time,
8886 };
8887
8888 static const struct file_operations btrfs_dir_file_operations = {
8889         .llseek         = generic_file_llseek,
8890         .read           = generic_read_dir,
8891         .iterate        = btrfs_real_readdir,
8892         .unlocked_ioctl = btrfs_ioctl,
8893 #ifdef CONFIG_COMPAT
8894         .compat_ioctl   = btrfs_ioctl,
8895 #endif
8896         .release        = btrfs_release_file,
8897         .fsync          = btrfs_sync_file,
8898 };
8899
8900 static struct extent_io_ops btrfs_extent_io_ops = {
8901         .fill_delalloc = run_delalloc_range,
8902         .submit_bio_hook = btrfs_submit_bio_hook,
8903         .merge_bio_hook = btrfs_merge_bio_hook,
8904         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
8905         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
8906         .writepage_start_hook = btrfs_writepage_start_hook,
8907         .set_bit_hook = btrfs_set_bit_hook,
8908         .clear_bit_hook = btrfs_clear_bit_hook,
8909         .merge_extent_hook = btrfs_merge_extent_hook,
8910         .split_extent_hook = btrfs_split_extent_hook,
8911 };
8912
8913 /*
8914  * btrfs doesn't support the bmap operation because swapfiles
8915  * use bmap to make a mapping of extents in the file.  They assume
8916  * these extents won't change over the life of the file and they
8917  * use the bmap result to do IO directly to the drive.
8918  *
8919  * the btrfs bmap call would return logical addresses that aren't
8920  * suitable for IO and they also will change frequently as COW
8921  * operations happen.  So, swapfile + btrfs == corruption.
8922  *
8923  * For now we're avoiding this by dropping bmap.
8924  */
8925 static const struct address_space_operations btrfs_aops = {
8926         .readpage       = btrfs_readpage,
8927         .writepage      = btrfs_writepage,
8928         .writepages     = btrfs_writepages,
8929         .readpages      = btrfs_readpages,
8930         .direct_IO      = btrfs_direct_IO,
8931         .invalidatepage = btrfs_invalidatepage,
8932         .releasepage    = btrfs_releasepage,
8933         .set_page_dirty = btrfs_set_page_dirty,
8934         .error_remove_page = generic_error_remove_page,
8935 };
8936
8937 static const struct address_space_operations btrfs_symlink_aops = {
8938         .readpage       = btrfs_readpage,
8939         .writepage      = btrfs_writepage,
8940         .invalidatepage = btrfs_invalidatepage,
8941         .releasepage    = btrfs_releasepage,
8942 };
8943
8944 static const struct inode_operations btrfs_file_inode_operations = {
8945         .getattr        = btrfs_getattr,
8946         .setattr        = btrfs_setattr,
8947         .setxattr       = btrfs_setxattr,
8948         .getxattr       = btrfs_getxattr,
8949         .listxattr      = btrfs_listxattr,
8950         .removexattr    = btrfs_removexattr,
8951         .permission     = btrfs_permission,
8952         .fiemap         = btrfs_fiemap,
8953         .get_acl        = btrfs_get_acl,
8954         .update_time    = btrfs_update_time,
8955 };
8956 static const struct inode_operations btrfs_special_inode_operations = {
8957         .getattr        = btrfs_getattr,
8958         .setattr        = btrfs_setattr,
8959         .permission     = btrfs_permission,
8960         .setxattr       = btrfs_setxattr,
8961         .getxattr       = btrfs_getxattr,
8962         .listxattr      = btrfs_listxattr,
8963         .removexattr    = btrfs_removexattr,
8964         .get_acl        = btrfs_get_acl,
8965         .update_time    = btrfs_update_time,
8966 };
8967 static const struct inode_operations btrfs_symlink_inode_operations = {
8968         .readlink       = generic_readlink,
8969         .follow_link    = page_follow_link_light,
8970         .put_link       = page_put_link,
8971         .getattr        = btrfs_getattr,
8972         .setattr        = btrfs_setattr,
8973         .permission     = btrfs_permission,
8974         .setxattr       = btrfs_setxattr,
8975         .getxattr       = btrfs_getxattr,
8976         .listxattr      = btrfs_listxattr,
8977         .removexattr    = btrfs_removexattr,
8978         .get_acl        = btrfs_get_acl,
8979         .update_time    = btrfs_update_time,
8980 };
8981
8982 const struct dentry_operations btrfs_dentry_operations = {
8983         .d_delete       = btrfs_dentry_delete,
8984         .d_release      = btrfs_dentry_release,
8985 };