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