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TOMOYO Linux Cross Reference
Linux/fs/btrfs/inode.c

Version: ~ [ linux-5.0-rc6 ] ~ [ linux-4.20.10 ] ~ [ linux-4.19.23 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.101 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.158 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.174 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.134 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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/bit_spinlock.h>
 36 #include <linux/xattr.h>
 37 #include <linux/posix_acl.h>
 38 #include <linux/falloc.h>
 39 #include <linux/slab.h>
 40 #include <linux/ratelimit.h>
 41 #include "compat.h"
 42 #include "ctree.h"
 43 #include "disk-io.h"
 44 #include "transaction.h"
 45 #include "btrfs_inode.h"
 46 #include "ioctl.h"
 47 #include "print-tree.h"
 48 #include "volumes.h"
 49 #include "ordered-data.h"
 50 #include "xattr.h"
 51 #include "tree-log.h"
 52 #include "compression.h"
 53 #include "locking.h"
 54 #include "free-space-cache.h"
 55 #include "inode-map.h"
 56 
 57 struct btrfs_iget_args {
 58         u64 ino;
 59         struct btrfs_root *root;
 60 };
 61 
 62 static const struct inode_operations btrfs_dir_inode_operations;
 63 static const struct inode_operations btrfs_symlink_inode_operations;
 64 static const struct inode_operations btrfs_dir_ro_inode_operations;
 65 static const struct inode_operations btrfs_special_inode_operations;
 66 static const struct inode_operations btrfs_file_inode_operations;
 67 static const struct address_space_operations btrfs_aops;
 68 static const struct address_space_operations btrfs_symlink_aops;
 69 static const struct file_operations btrfs_dir_file_operations;
 70 static struct extent_io_ops btrfs_extent_io_ops;
 71 
 72 static struct kmem_cache *btrfs_inode_cachep;
 73 struct kmem_cache *btrfs_trans_handle_cachep;
 74 struct kmem_cache *btrfs_transaction_cachep;
 75 struct kmem_cache *btrfs_path_cachep;
 76 struct kmem_cache *btrfs_free_space_cachep;
 77 
 78 #define S_SHIFT 12
 79 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
 80         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
 81         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
 82         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
 83         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
 84         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
 85         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
 86         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
 87 };
 88 
 89 static int btrfs_setsize(struct inode *inode, loff_t newsize);
 90 static int btrfs_truncate(struct inode *inode);
 91 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
 92 static noinline int cow_file_range(struct inode *inode,
 93                                    struct page *locked_page,
 94                                    u64 start, u64 end, int *page_started,
 95                                    unsigned long *nr_written, int unlock);
 96 
 97 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 98                                      struct inode *inode,  struct inode *dir,
 99                                      const struct qstr *qstr)
100 {
101         int err;
102 
103         err = btrfs_init_acl(trans, inode, dir);
104         if (!err)
105                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
106         return err;
107 }
108 
109 /*
110  * this does all the hard work for inserting an inline extent into
111  * the btree.  The caller should have done a btrfs_drop_extents so that
112  * no overlapping inline items exist in the btree
113  */
114 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
115                                 struct btrfs_root *root, struct inode *inode,
116                                 u64 start, size_t size, size_t compressed_size,
117                                 int compress_type,
118                                 struct page **compressed_pages)
119 {
120         struct btrfs_key key;
121         struct btrfs_path *path;
122         struct extent_buffer *leaf;
123         struct page *page = NULL;
124         char *kaddr;
125         unsigned long ptr;
126         struct btrfs_file_extent_item *ei;
127         int err = 0;
128         int ret;
129         size_t cur_size = size;
130         size_t datasize;
131         unsigned long offset;
132 
133         if (compressed_size && compressed_pages)
134                 cur_size = compressed_size;
135 
136         path = btrfs_alloc_path();
137         if (!path)
138                 return -ENOMEM;
139 
140         path->leave_spinning = 1;
141 
142         key.objectid = btrfs_ino(inode);
143         key.offset = start;
144         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
145         datasize = btrfs_file_extent_calc_inline_size(cur_size);
146 
147         inode_add_bytes(inode, size);
148         ret = btrfs_insert_empty_item(trans, root, path, &key,
149                                       datasize);
150         BUG_ON(ret);
151         if (ret) {
152                 err = ret;
153                 goto fail;
154         }
155         leaf = path->nodes[0];
156         ei = btrfs_item_ptr(leaf, path->slots[0],
157                             struct btrfs_file_extent_item);
158         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
159         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
160         btrfs_set_file_extent_encryption(leaf, ei, 0);
161         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
162         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
163         ptr = btrfs_file_extent_inline_start(ei);
164 
165         if (compress_type != BTRFS_COMPRESS_NONE) {
166                 struct page *cpage;
167                 int i = 0;
168                 while (compressed_size > 0) {
169                         cpage = compressed_pages[i];
170                         cur_size = min_t(unsigned long, compressed_size,
171                                        PAGE_CACHE_SIZE);
172 
173                         kaddr = kmap_atomic(cpage, KM_USER0);
174                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
175                         kunmap_atomic(kaddr, KM_USER0);
176 
177                         i++;
178                         ptr += cur_size;
179                         compressed_size -= cur_size;
180                 }
181                 btrfs_set_file_extent_compression(leaf, ei,
182                                                   compress_type);
183         } else {
184                 page = find_get_page(inode->i_mapping,
185                                      start >> PAGE_CACHE_SHIFT);
186                 btrfs_set_file_extent_compression(leaf, ei, 0);
187                 kaddr = kmap_atomic(page, KM_USER0);
188                 offset = start & (PAGE_CACHE_SIZE - 1);
189                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
190                 kunmap_atomic(kaddr, KM_USER0);
191                 page_cache_release(page);
192         }
193         btrfs_mark_buffer_dirty(leaf);
194         btrfs_free_path(path);
195 
196         /*
197          * we're an inline extent, so nobody can
198          * extend the file past i_size without locking
199          * a page we already have locked.
200          *
201          * We must do any isize and inode updates
202          * before we unlock the pages.  Otherwise we
203          * could end up racing with unlink.
204          */
205         BTRFS_I(inode)->disk_i_size = inode->i_size;
206         btrfs_update_inode(trans, root, inode);
207 
208         return 0;
209 fail:
210         btrfs_free_path(path);
211         return err;
212 }
213 
214 
215 /*
216  * conditionally insert an inline extent into the file.  This
217  * does the checks required to make sure the data is small enough
218  * to fit as an inline extent.
219  */
220 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
221                                  struct btrfs_root *root,
222                                  struct inode *inode, u64 start, u64 end,
223                                  size_t compressed_size, int compress_type,
224                                  struct page **compressed_pages)
225 {
226         u64 isize = i_size_read(inode);
227         u64 actual_end = min(end + 1, isize);
228         u64 inline_len = actual_end - start;
229         u64 aligned_end = (end + root->sectorsize - 1) &
230                         ~((u64)root->sectorsize - 1);
231         u64 hint_byte;
232         u64 data_len = inline_len;
233         int ret;
234 
235         if (compressed_size)
236                 data_len = compressed_size;
237 
238         if (start > 0 ||
239             actual_end >= PAGE_CACHE_SIZE ||
240             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
241             (!compressed_size &&
242             (actual_end & (root->sectorsize - 1)) == 0) ||
243             end + 1 < isize ||
244             data_len > root->fs_info->max_inline) {
245                 return 1;
246         }
247 
248         ret = btrfs_drop_extents(trans, inode, start, aligned_end,
249                                  &hint_byte, 1);
250         BUG_ON(ret);
251 
252         if (isize > actual_end)
253                 inline_len = min_t(u64, isize, actual_end);
254         ret = insert_inline_extent(trans, root, inode, start,
255                                    inline_len, compressed_size,
256                                    compress_type, compressed_pages);
257         BUG_ON(ret);
258         btrfs_delalloc_release_metadata(inode, end + 1 - start);
259         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
260         return 0;
261 }
262 
263 struct async_extent {
264         u64 start;
265         u64 ram_size;
266         u64 compressed_size;
267         struct page **pages;
268         unsigned long nr_pages;
269         int compress_type;
270         struct list_head list;
271 };
272 
273 struct async_cow {
274         struct inode *inode;
275         struct btrfs_root *root;
276         struct page *locked_page;
277         u64 start;
278         u64 end;
279         struct list_head extents;
280         struct btrfs_work work;
281 };
282 
283 static noinline int add_async_extent(struct async_cow *cow,
284                                      u64 start, u64 ram_size,
285                                      u64 compressed_size,
286                                      struct page **pages,
287                                      unsigned long nr_pages,
288                                      int compress_type)
289 {
290         struct async_extent *async_extent;
291 
292         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
293         BUG_ON(!async_extent);
294         async_extent->start = start;
295         async_extent->ram_size = ram_size;
296         async_extent->compressed_size = compressed_size;
297         async_extent->pages = pages;
298         async_extent->nr_pages = nr_pages;
299         async_extent->compress_type = compress_type;
300         list_add_tail(&async_extent->list, &cow->extents);
301         return 0;
302 }
303 
304 /*
305  * we create compressed extents in two phases.  The first
306  * phase compresses a range of pages that have already been
307  * locked (both pages and state bits are locked).
308  *
309  * This is done inside an ordered work queue, and the compression
310  * is spread across many cpus.  The actual IO submission is step
311  * two, and the ordered work queue takes care of making sure that
312  * happens in the same order things were put onto the queue by
313  * writepages and friends.
314  *
315  * If this code finds it can't get good compression, it puts an
316  * entry onto the work queue to write the uncompressed bytes.  This
317  * makes sure that both compressed inodes and uncompressed inodes
318  * are written in the same order that pdflush sent them down.
319  */
320 static noinline int compress_file_range(struct inode *inode,
321                                         struct page *locked_page,
322                                         u64 start, u64 end,
323                                         struct async_cow *async_cow,
324                                         int *num_added)
325 {
326         struct btrfs_root *root = BTRFS_I(inode)->root;
327         struct btrfs_trans_handle *trans;
328         u64 num_bytes;
329         u64 blocksize = root->sectorsize;
330         u64 actual_end;
331         u64 isize = i_size_read(inode);
332         int ret = 0;
333         struct page **pages = NULL;
334         unsigned long nr_pages;
335         unsigned long nr_pages_ret = 0;
336         unsigned long total_compressed = 0;
337         unsigned long total_in = 0;
338         unsigned long max_compressed = 128 * 1024;
339         unsigned long max_uncompressed = 128 * 1024;
340         int i;
341         int will_compress;
342         int compress_type = root->fs_info->compress_type;
343 
344         /* if this is a small write inside eof, kick off a defragbot */
345         if (end <= BTRFS_I(inode)->disk_i_size && (end - start + 1) < 16 * 1024)
346                 btrfs_add_inode_defrag(NULL, inode);
347 
348         actual_end = min_t(u64, isize, end + 1);
349 again:
350         will_compress = 0;
351         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
352         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
353 
354         /*
355          * we don't want to send crud past the end of i_size through
356          * compression, that's just a waste of CPU time.  So, if the
357          * end of the file is before the start of our current
358          * requested range of bytes, we bail out to the uncompressed
359          * cleanup code that can deal with all of this.
360          *
361          * It isn't really the fastest way to fix things, but this is a
362          * very uncommon corner.
363          */
364         if (actual_end <= start)
365                 goto cleanup_and_bail_uncompressed;
366 
367         total_compressed = actual_end - start;
368 
369         /* we want to make sure that amount of ram required to uncompress
370          * an extent is reasonable, so we limit the total size in ram
371          * of a compressed extent to 128k.  This is a crucial number
372          * because it also controls how easily we can spread reads across
373          * cpus for decompression.
374          *
375          * We also want to make sure the amount of IO required to do
376          * a random read is reasonably small, so we limit the size of
377          * a compressed extent to 128k.
378          */
379         total_compressed = min(total_compressed, max_uncompressed);
380         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
381         num_bytes = max(blocksize,  num_bytes);
382         total_in = 0;
383         ret = 0;
384 
385         /*
386          * we do compression for mount -o compress and when the
387          * inode has not been flagged as nocompress.  This flag can
388          * change at any time if we discover bad compression ratios.
389          */
390         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
391             (btrfs_test_opt(root, COMPRESS) ||
392              (BTRFS_I(inode)->force_compress) ||
393              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
394                 WARN_ON(pages);
395                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
396                 BUG_ON(!pages);
397 
398                 if (BTRFS_I(inode)->force_compress)
399                         compress_type = BTRFS_I(inode)->force_compress;
400 
401                 ret = btrfs_compress_pages(compress_type,
402                                            inode->i_mapping, start,
403                                            total_compressed, pages,
404                                            nr_pages, &nr_pages_ret,
405                                            &total_in,
406                                            &total_compressed,
407                                            max_compressed);
408 
409                 if (!ret) {
410                         unsigned long offset = total_compressed &
411                                 (PAGE_CACHE_SIZE - 1);
412                         struct page *page = pages[nr_pages_ret - 1];
413                         char *kaddr;
414 
415                         /* zero the tail end of the last page, we might be
416                          * sending it down to disk
417                          */
418                         if (offset) {
419                                 kaddr = kmap_atomic(page, KM_USER0);
420                                 memset(kaddr + offset, 0,
421                                        PAGE_CACHE_SIZE - offset);
422                                 kunmap_atomic(kaddr, KM_USER0);
423                         }
424                         will_compress = 1;
425                 }
426         }
427         if (start == 0) {
428                 trans = btrfs_join_transaction(root);
429                 BUG_ON(IS_ERR(trans));
430                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
431 
432                 /* lets try to make an inline extent */
433                 if (ret || total_in < (actual_end - start)) {
434                         /* we didn't compress the entire range, try
435                          * to make an uncompressed inline extent.
436                          */
437                         ret = cow_file_range_inline(trans, root, inode,
438                                                     start, end, 0, 0, NULL);
439                 } else {
440                         /* try making a compressed inline extent */
441                         ret = cow_file_range_inline(trans, root, inode,
442                                                     start, end,
443                                                     total_compressed,
444                                                     compress_type, pages);
445                 }
446                 if (ret == 0) {
447                         /*
448                          * inline extent creation worked, we don't need
449                          * to create any more async work items.  Unlock
450                          * and free up our temp pages.
451                          */
452                         extent_clear_unlock_delalloc(inode,
453                              &BTRFS_I(inode)->io_tree,
454                              start, end, NULL,
455                              EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
456                              EXTENT_CLEAR_DELALLOC |
457                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
458 
459                         btrfs_end_transaction(trans, root);
460                         goto free_pages_out;
461                 }
462                 btrfs_end_transaction(trans, root);
463         }
464 
465         if (will_compress) {
466                 /*
467                  * we aren't doing an inline extent round the compressed size
468                  * up to a block size boundary so the allocator does sane
469                  * things
470                  */
471                 total_compressed = (total_compressed + blocksize - 1) &
472                         ~(blocksize - 1);
473 
474                 /*
475                  * one last check to make sure the compression is really a
476                  * win, compare the page count read with the blocks on disk
477                  */
478                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
479                         ~(PAGE_CACHE_SIZE - 1);
480                 if (total_compressed >= total_in) {
481                         will_compress = 0;
482                 } else {
483                         num_bytes = total_in;
484                 }
485         }
486         if (!will_compress && pages) {
487                 /*
488                  * the compression code ran but failed to make things smaller,
489                  * free any pages it allocated and our page pointer array
490                  */
491                 for (i = 0; i < nr_pages_ret; i++) {
492                         WARN_ON(pages[i]->mapping);
493                         page_cache_release(pages[i]);
494                 }
495                 kfree(pages);
496                 pages = NULL;
497                 total_compressed = 0;
498                 nr_pages_ret = 0;
499 
500                 /* flag the file so we don't compress in the future */
501                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
502                     !(BTRFS_I(inode)->force_compress)) {
503                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
504                 }
505         }
506         if (will_compress) {
507                 *num_added += 1;
508 
509                 /* the async work queues will take care of doing actual
510                  * allocation on disk for these compressed pages,
511                  * and will submit them to the elevator.
512                  */
513                 add_async_extent(async_cow, start, num_bytes,
514                                  total_compressed, pages, nr_pages_ret,
515                                  compress_type);
516 
517                 if (start + num_bytes < end) {
518                         start += num_bytes;
519                         pages = NULL;
520                         cond_resched();
521                         goto again;
522                 }
523         } else {
524 cleanup_and_bail_uncompressed:
525                 /*
526                  * No compression, but we still need to write the pages in
527                  * the file we've been given so far.  redirty the locked
528                  * page if it corresponds to our extent and set things up
529                  * for the async work queue to run cow_file_range to do
530                  * the normal delalloc dance
531                  */
532                 if (page_offset(locked_page) >= start &&
533                     page_offset(locked_page) <= end) {
534                         __set_page_dirty_nobuffers(locked_page);
535                         /* unlocked later on in the async handlers */
536                 }
537                 add_async_extent(async_cow, start, end - start + 1,
538                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
539                 *num_added += 1;
540         }
541 
542 out:
543         return 0;
544 
545 free_pages_out:
546         for (i = 0; i < nr_pages_ret; i++) {
547                 WARN_ON(pages[i]->mapping);
548                 page_cache_release(pages[i]);
549         }
550         kfree(pages);
551 
552         goto out;
553 }
554 
555 /*
556  * phase two of compressed writeback.  This is the ordered portion
557  * of the code, which only gets called in the order the work was
558  * queued.  We walk all the async extents created by compress_file_range
559  * and send them down to the disk.
560  */
561 static noinline int submit_compressed_extents(struct inode *inode,
562                                               struct async_cow *async_cow)
563 {
564         struct async_extent *async_extent;
565         u64 alloc_hint = 0;
566         struct btrfs_trans_handle *trans;
567         struct btrfs_key ins;
568         struct extent_map *em;
569         struct btrfs_root *root = BTRFS_I(inode)->root;
570         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
571         struct extent_io_tree *io_tree;
572         int ret = 0;
573 
574         if (list_empty(&async_cow->extents))
575                 return 0;
576 
577 
578         while (!list_empty(&async_cow->extents)) {
579                 async_extent = list_entry(async_cow->extents.next,
580                                           struct async_extent, list);
581                 list_del(&async_extent->list);
582 
583                 io_tree = &BTRFS_I(inode)->io_tree;
584 
585 retry:
586                 /* did the compression code fall back to uncompressed IO? */
587                 if (!async_extent->pages) {
588                         int page_started = 0;
589                         unsigned long nr_written = 0;
590 
591                         lock_extent(io_tree, async_extent->start,
592                                          async_extent->start +
593                                          async_extent->ram_size - 1, GFP_NOFS);
594 
595                         /* allocate blocks */
596                         ret = cow_file_range(inode, async_cow->locked_page,
597                                              async_extent->start,
598                                              async_extent->start +
599                                              async_extent->ram_size - 1,
600                                              &page_started, &nr_written, 0);
601 
602                         /*
603                          * if page_started, cow_file_range inserted an
604                          * inline extent and took care of all the unlocking
605                          * and IO for us.  Otherwise, we need to submit
606                          * all those pages down to the drive.
607                          */
608                         if (!page_started && !ret)
609                                 extent_write_locked_range(io_tree,
610                                                   inode, async_extent->start,
611                                                   async_extent->start +
612                                                   async_extent->ram_size - 1,
613                                                   btrfs_get_extent,
614                                                   WB_SYNC_ALL);
615                         kfree(async_extent);
616                         cond_resched();
617                         continue;
618                 }
619 
620                 lock_extent(io_tree, async_extent->start,
621                             async_extent->start + async_extent->ram_size - 1,
622                             GFP_NOFS);
623 
624                 trans = btrfs_join_transaction(root);
625                 BUG_ON(IS_ERR(trans));
626                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
627                 ret = btrfs_reserve_extent(trans, root,
628                                            async_extent->compressed_size,
629                                            async_extent->compressed_size,
630                                            0, alloc_hint,
631                                            (u64)-1, &ins, 1);
632                 btrfs_end_transaction(trans, root);
633 
634                 if (ret) {
635                         int i;
636                         for (i = 0; i < async_extent->nr_pages; i++) {
637                                 WARN_ON(async_extent->pages[i]->mapping);
638                                 page_cache_release(async_extent->pages[i]);
639                         }
640                         kfree(async_extent->pages);
641                         async_extent->nr_pages = 0;
642                         async_extent->pages = NULL;
643                         unlock_extent(io_tree, async_extent->start,
644                                       async_extent->start +
645                                       async_extent->ram_size - 1, GFP_NOFS);
646                         goto retry;
647                 }
648 
649                 /*
650                  * here we're doing allocation and writeback of the
651                  * compressed pages
652                  */
653                 btrfs_drop_extent_cache(inode, async_extent->start,
654                                         async_extent->start +
655                                         async_extent->ram_size - 1, 0);
656 
657                 em = alloc_extent_map();
658                 BUG_ON(!em);
659                 em->start = async_extent->start;
660                 em->len = async_extent->ram_size;
661                 em->orig_start = em->start;
662 
663                 em->block_start = ins.objectid;
664                 em->block_len = ins.offset;
665                 em->bdev = root->fs_info->fs_devices->latest_bdev;
666                 em->compress_type = async_extent->compress_type;
667                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
668                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
669 
670                 while (1) {
671                         write_lock(&em_tree->lock);
672                         ret = add_extent_mapping(em_tree, em);
673                         write_unlock(&em_tree->lock);
674                         if (ret != -EEXIST) {
675                                 free_extent_map(em);
676                                 break;
677                         }
678                         btrfs_drop_extent_cache(inode, async_extent->start,
679                                                 async_extent->start +
680                                                 async_extent->ram_size - 1, 0);
681                 }
682 
683                 ret = btrfs_add_ordered_extent_compress(inode,
684                                                 async_extent->start,
685                                                 ins.objectid,
686                                                 async_extent->ram_size,
687                                                 ins.offset,
688                                                 BTRFS_ORDERED_COMPRESSED,
689                                                 async_extent->compress_type);
690                 BUG_ON(ret);
691 
692                 /*
693                  * clear dirty, set writeback and unlock the pages.
694                  */
695                 extent_clear_unlock_delalloc(inode,
696                                 &BTRFS_I(inode)->io_tree,
697                                 async_extent->start,
698                                 async_extent->start +
699                                 async_extent->ram_size - 1,
700                                 NULL, EXTENT_CLEAR_UNLOCK_PAGE |
701                                 EXTENT_CLEAR_UNLOCK |
702                                 EXTENT_CLEAR_DELALLOC |
703                                 EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
704 
705                 ret = btrfs_submit_compressed_write(inode,
706                                     async_extent->start,
707                                     async_extent->ram_size,
708                                     ins.objectid,
709                                     ins.offset, async_extent->pages,
710                                     async_extent->nr_pages);
711 
712                 BUG_ON(ret);
713                 alloc_hint = ins.objectid + ins.offset;
714                 kfree(async_extent);
715                 cond_resched();
716         }
717 
718         return 0;
719 }
720 
721 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
722                                       u64 num_bytes)
723 {
724         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
725         struct extent_map *em;
726         u64 alloc_hint = 0;
727 
728         read_lock(&em_tree->lock);
729         em = search_extent_mapping(em_tree, start, num_bytes);
730         if (em) {
731                 /*
732                  * if block start isn't an actual block number then find the
733                  * first block in this inode and use that as a hint.  If that
734                  * block is also bogus then just don't worry about it.
735                  */
736                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
737                         free_extent_map(em);
738                         em = search_extent_mapping(em_tree, 0, 0);
739                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
740                                 alloc_hint = em->block_start;
741                         if (em)
742                                 free_extent_map(em);
743                 } else {
744                         alloc_hint = em->block_start;
745                         free_extent_map(em);
746                 }
747         }
748         read_unlock(&em_tree->lock);
749 
750         return alloc_hint;
751 }
752 
753 static inline bool is_free_space_inode(struct btrfs_root *root,
754                                        struct inode *inode)
755 {
756         if (root == root->fs_info->tree_root ||
757             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID)
758                 return true;
759         return false;
760 }
761 
762 /*
763  * when extent_io.c finds a delayed allocation range in the file,
764  * the call backs end up in this code.  The basic idea is to
765  * allocate extents on disk for the range, and create ordered data structs
766  * in ram to track those extents.
767  *
768  * locked_page is the page that writepage had locked already.  We use
769  * it to make sure we don't do extra locks or unlocks.
770  *
771  * *page_started is set to one if we unlock locked_page and do everything
772  * required to start IO on it.  It may be clean and already done with
773  * IO when we return.
774  */
775 static noinline int cow_file_range(struct inode *inode,
776                                    struct page *locked_page,
777                                    u64 start, u64 end, int *page_started,
778                                    unsigned long *nr_written,
779                                    int unlock)
780 {
781         struct btrfs_root *root = BTRFS_I(inode)->root;
782         struct btrfs_trans_handle *trans;
783         u64 alloc_hint = 0;
784         u64 num_bytes;
785         unsigned long ram_size;
786         u64 disk_num_bytes;
787         u64 cur_alloc_size;
788         u64 blocksize = root->sectorsize;
789         struct btrfs_key ins;
790         struct extent_map *em;
791         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
792         int ret = 0;
793 
794         BUG_ON(is_free_space_inode(root, inode));
795         trans = btrfs_join_transaction(root);
796         BUG_ON(IS_ERR(trans));
797         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
798 
799         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
800         num_bytes = max(blocksize,  num_bytes);
801         disk_num_bytes = num_bytes;
802         ret = 0;
803 
804         /* if this is a small write inside eof, kick off defrag */
805         if (end <= BTRFS_I(inode)->disk_i_size && num_bytes < 64 * 1024)
806                 btrfs_add_inode_defrag(trans, inode);
807 
808         if (start == 0) {
809                 /* lets try to make an inline extent */
810                 ret = cow_file_range_inline(trans, root, inode,
811                                             start, end, 0, 0, NULL);
812                 if (ret == 0) {
813                         extent_clear_unlock_delalloc(inode,
814                                      &BTRFS_I(inode)->io_tree,
815                                      start, end, NULL,
816                                      EXTENT_CLEAR_UNLOCK_PAGE |
817                                      EXTENT_CLEAR_UNLOCK |
818                                      EXTENT_CLEAR_DELALLOC |
819                                      EXTENT_CLEAR_DIRTY |
820                                      EXTENT_SET_WRITEBACK |
821                                      EXTENT_END_WRITEBACK);
822 
823                         *nr_written = *nr_written +
824                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
825                         *page_started = 1;
826                         ret = 0;
827                         goto out;
828                 }
829         }
830 
831         BUG_ON(disk_num_bytes >
832                btrfs_super_total_bytes(&root->fs_info->super_copy));
833 
834         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
835         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
836 
837         while (disk_num_bytes > 0) {
838                 unsigned long op;
839 
840                 cur_alloc_size = disk_num_bytes;
841                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
842                                            root->sectorsize, 0, alloc_hint,
843                                            (u64)-1, &ins, 1);
844                 BUG_ON(ret);
845 
846                 em = alloc_extent_map();
847                 BUG_ON(!em);
848                 em->start = start;
849                 em->orig_start = em->start;
850                 ram_size = ins.offset;
851                 em->len = ins.offset;
852 
853                 em->block_start = ins.objectid;
854                 em->block_len = ins.offset;
855                 em->bdev = root->fs_info->fs_devices->latest_bdev;
856                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
857 
858                 while (1) {
859                         write_lock(&em_tree->lock);
860                         ret = add_extent_mapping(em_tree, em);
861                         write_unlock(&em_tree->lock);
862                         if (ret != -EEXIST) {
863                                 free_extent_map(em);
864                                 break;
865                         }
866                         btrfs_drop_extent_cache(inode, start,
867                                                 start + ram_size - 1, 0);
868                 }
869 
870                 cur_alloc_size = ins.offset;
871                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
872                                                ram_size, cur_alloc_size, 0);
873                 BUG_ON(ret);
874 
875                 if (root->root_key.objectid ==
876                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
877                         ret = btrfs_reloc_clone_csums(inode, start,
878                                                       cur_alloc_size);
879                         BUG_ON(ret);
880                 }
881 
882                 if (disk_num_bytes < cur_alloc_size)
883                         break;
884 
885                 /* we're not doing compressed IO, don't unlock the first
886                  * page (which the caller expects to stay locked), don't
887                  * clear any dirty bits and don't set any writeback bits
888                  *
889                  * Do set the Private2 bit so we know this page was properly
890                  * setup for writepage
891                  */
892                 op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
893                 op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
894                         EXTENT_SET_PRIVATE2;
895 
896                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
897                                              start, start + ram_size - 1,
898                                              locked_page, op);
899                 disk_num_bytes -= cur_alloc_size;
900                 num_bytes -= cur_alloc_size;
901                 alloc_hint = ins.objectid + ins.offset;
902                 start += cur_alloc_size;
903         }
904 out:
905         ret = 0;
906         btrfs_end_transaction(trans, root);
907 
908         return ret;
909 }
910 
911 /*
912  * work queue call back to started compression on a file and pages
913  */
914 static noinline void async_cow_start(struct btrfs_work *work)
915 {
916         struct async_cow *async_cow;
917         int num_added = 0;
918         async_cow = container_of(work, struct async_cow, work);
919 
920         compress_file_range(async_cow->inode, async_cow->locked_page,
921                             async_cow->start, async_cow->end, async_cow,
922                             &num_added);
923         if (num_added == 0)
924                 async_cow->inode = NULL;
925 }
926 
927 /*
928  * work queue call back to submit previously compressed pages
929  */
930 static noinline void async_cow_submit(struct btrfs_work *work)
931 {
932         struct async_cow *async_cow;
933         struct btrfs_root *root;
934         unsigned long nr_pages;
935 
936         async_cow = container_of(work, struct async_cow, work);
937 
938         root = async_cow->root;
939         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
940                 PAGE_CACHE_SHIFT;
941 
942         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
943 
944         if (atomic_read(&root->fs_info->async_delalloc_pages) <
945             5 * 1042 * 1024 &&
946             waitqueue_active(&root->fs_info->async_submit_wait))
947                 wake_up(&root->fs_info->async_submit_wait);
948 
949         if (async_cow->inode)
950                 submit_compressed_extents(async_cow->inode, async_cow);
951 }
952 
953 static noinline void async_cow_free(struct btrfs_work *work)
954 {
955         struct async_cow *async_cow;
956         async_cow = container_of(work, struct async_cow, work);
957         kfree(async_cow);
958 }
959 
960 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
961                                 u64 start, u64 end, int *page_started,
962                                 unsigned long *nr_written)
963 {
964         struct async_cow *async_cow;
965         struct btrfs_root *root = BTRFS_I(inode)->root;
966         unsigned long nr_pages;
967         u64 cur_end;
968         int limit = 10 * 1024 * 1042;
969 
970         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
971                          1, 0, NULL, GFP_NOFS);
972         while (start < end) {
973                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
974                 BUG_ON(!async_cow);
975                 async_cow->inode = inode;
976                 async_cow->root = root;
977                 async_cow->locked_page = locked_page;
978                 async_cow->start = start;
979 
980                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
981                         cur_end = end;
982                 else
983                         cur_end = min(end, start + 512 * 1024 - 1);
984 
985                 async_cow->end = cur_end;
986                 INIT_LIST_HEAD(&async_cow->extents);
987 
988                 async_cow->work.func = async_cow_start;
989                 async_cow->work.ordered_func = async_cow_submit;
990                 async_cow->work.ordered_free = async_cow_free;
991                 async_cow->work.flags = 0;
992 
993                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
994                         PAGE_CACHE_SHIFT;
995                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
996 
997                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
998                                    &async_cow->work);
999 
1000                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1001                         wait_event(root->fs_info->async_submit_wait,
1002                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1003                             limit));
1004                 }
1005 
1006                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1007                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1008                         wait_event(root->fs_info->async_submit_wait,
1009                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1010                            0));
1011                 }
1012 
1013                 *nr_written += nr_pages;
1014                 start = cur_end + 1;
1015         }
1016         *page_started = 1;
1017         return 0;
1018 }
1019 
1020 static noinline int csum_exist_in_range(struct btrfs_root *root,
1021                                         u64 bytenr, u64 num_bytes)
1022 {
1023         int ret;
1024         struct btrfs_ordered_sum *sums;
1025         LIST_HEAD(list);
1026 
1027         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1028                                        bytenr + num_bytes - 1, &list, 0);
1029         if (ret == 0 && list_empty(&list))
1030                 return 0;
1031 
1032         while (!list_empty(&list)) {
1033                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1034                 list_del(&sums->list);
1035                 kfree(sums);
1036         }
1037         return 1;
1038 }
1039 
1040 /*
1041  * when nowcow writeback call back.  This checks for snapshots or COW copies
1042  * of the extents that exist in the file, and COWs the file as required.
1043  *
1044  * If no cow copies or snapshots exist, we write directly to the existing
1045  * blocks on disk
1046  */
1047 static noinline int run_delalloc_nocow(struct inode *inode,
1048                                        struct page *locked_page,
1049                               u64 start, u64 end, int *page_started, int force,
1050                               unsigned long *nr_written)
1051 {
1052         struct btrfs_root *root = BTRFS_I(inode)->root;
1053         struct btrfs_trans_handle *trans;
1054         struct extent_buffer *leaf;
1055         struct btrfs_path *path;
1056         struct btrfs_file_extent_item *fi;
1057         struct btrfs_key found_key;
1058         u64 cow_start;
1059         u64 cur_offset;
1060         u64 extent_end;
1061         u64 extent_offset;
1062         u64 disk_bytenr;
1063         u64 num_bytes;
1064         int extent_type;
1065         int ret;
1066         int type;
1067         int nocow;
1068         int check_prev = 1;
1069         bool nolock;
1070         u64 ino = btrfs_ino(inode);
1071 
1072         path = btrfs_alloc_path();
1073         BUG_ON(!path);
1074 
1075         nolock = is_free_space_inode(root, inode);
1076 
1077         if (nolock)
1078                 trans = btrfs_join_transaction_nolock(root);
1079         else
1080                 trans = btrfs_join_transaction(root);
1081 
1082         BUG_ON(IS_ERR(trans));
1083         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1084 
1085         cow_start = (u64)-1;
1086         cur_offset = start;
1087         while (1) {
1088                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1089                                                cur_offset, 0);
1090                 BUG_ON(ret < 0);
1091                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1092                         leaf = path->nodes[0];
1093                         btrfs_item_key_to_cpu(leaf, &found_key,
1094                                               path->slots[0] - 1);
1095                         if (found_key.objectid == ino &&
1096                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1097                                 path->slots[0]--;
1098                 }
1099                 check_prev = 0;
1100 next_slot:
1101                 leaf = path->nodes[0];
1102                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1103                         ret = btrfs_next_leaf(root, path);
1104                         if (ret < 0)
1105                                 BUG_ON(1);
1106                         if (ret > 0)
1107                                 break;
1108                         leaf = path->nodes[0];
1109                 }
1110 
1111                 nocow = 0;
1112                 disk_bytenr = 0;
1113                 num_bytes = 0;
1114                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1115 
1116                 if (found_key.objectid > ino ||
1117                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1118                     found_key.offset > end)
1119                         break;
1120 
1121                 if (found_key.offset > cur_offset) {
1122                         extent_end = found_key.offset;
1123                         extent_type = 0;
1124                         goto out_check;
1125                 }
1126 
1127                 fi = btrfs_item_ptr(leaf, path->slots[0],
1128                                     struct btrfs_file_extent_item);
1129                 extent_type = btrfs_file_extent_type(leaf, fi);
1130 
1131                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1132                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1133                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1134                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1135                         extent_end = found_key.offset +
1136                                 btrfs_file_extent_num_bytes(leaf, fi);
1137                         if (extent_end <= start) {
1138                                 path->slots[0]++;
1139                                 goto next_slot;
1140                         }
1141                         if (disk_bytenr == 0)
1142                                 goto out_check;
1143                         if (btrfs_file_extent_compression(leaf, fi) ||
1144                             btrfs_file_extent_encryption(leaf, fi) ||
1145                             btrfs_file_extent_other_encoding(leaf, fi))
1146                                 goto out_check;
1147                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1148                                 goto out_check;
1149                         if (btrfs_extent_readonly(root, disk_bytenr))
1150                                 goto out_check;
1151                         if (btrfs_cross_ref_exist(trans, root, ino,
1152                                                   found_key.offset -
1153                                                   extent_offset, disk_bytenr))
1154                                 goto out_check;
1155                         disk_bytenr += extent_offset;
1156                         disk_bytenr += cur_offset - found_key.offset;
1157                         num_bytes = min(end + 1, extent_end) - cur_offset;
1158                         /*
1159                          * force cow if csum exists in the range.
1160                          * this ensure that csum for a given extent are
1161                          * either valid or do not exist.
1162                          */
1163                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1164                                 goto out_check;
1165                         nocow = 1;
1166                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1167                         extent_end = found_key.offset +
1168                                 btrfs_file_extent_inline_len(leaf, fi);
1169                         extent_end = ALIGN(extent_end, root->sectorsize);
1170                 } else {
1171                         BUG_ON(1);
1172                 }
1173 out_check:
1174                 if (extent_end <= start) {
1175                         path->slots[0]++;
1176                         goto next_slot;
1177                 }
1178                 if (!nocow) {
1179                         if (cow_start == (u64)-1)
1180                                 cow_start = cur_offset;
1181                         cur_offset = extent_end;
1182                         if (cur_offset > end)
1183                                 break;
1184                         path->slots[0]++;
1185                         goto next_slot;
1186                 }
1187 
1188                 btrfs_release_path(path);
1189                 if (cow_start != (u64)-1) {
1190                         ret = cow_file_range(inode, locked_page, cow_start,
1191                                         found_key.offset - 1, page_started,
1192                                         nr_written, 1);
1193                         BUG_ON(ret);
1194                         cow_start = (u64)-1;
1195                 }
1196 
1197                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1198                         struct extent_map *em;
1199                         struct extent_map_tree *em_tree;
1200                         em_tree = &BTRFS_I(inode)->extent_tree;
1201                         em = alloc_extent_map();
1202                         BUG_ON(!em);
1203                         em->start = cur_offset;
1204                         em->orig_start = em->start;
1205                         em->len = num_bytes;
1206                         em->block_len = num_bytes;
1207                         em->block_start = disk_bytenr;
1208                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1209                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1210                         while (1) {
1211                                 write_lock(&em_tree->lock);
1212                                 ret = add_extent_mapping(em_tree, em);
1213                                 write_unlock(&em_tree->lock);
1214                                 if (ret != -EEXIST) {
1215                                         free_extent_map(em);
1216                                         break;
1217                                 }
1218                                 btrfs_drop_extent_cache(inode, em->start,
1219                                                 em->start + em->len - 1, 0);
1220                         }
1221                         type = BTRFS_ORDERED_PREALLOC;
1222                 } else {
1223                         type = BTRFS_ORDERED_NOCOW;
1224                 }
1225 
1226                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1227                                                num_bytes, num_bytes, type);
1228                 BUG_ON(ret);
1229 
1230                 if (root->root_key.objectid ==
1231                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1232                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1233                                                       num_bytes);
1234                         BUG_ON(ret);
1235                 }
1236 
1237                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1238                                 cur_offset, cur_offset + num_bytes - 1,
1239                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1240                                 EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
1241                                 EXTENT_SET_PRIVATE2);
1242                 cur_offset = extent_end;
1243                 if (cur_offset > end)
1244                         break;
1245         }
1246         btrfs_release_path(path);
1247 
1248         if (cur_offset <= end && cow_start == (u64)-1)
1249                 cow_start = cur_offset;
1250         if (cow_start != (u64)-1) {
1251                 ret = cow_file_range(inode, locked_page, cow_start, end,
1252                                      page_started, nr_written, 1);
1253                 BUG_ON(ret);
1254         }
1255 
1256         if (nolock) {
1257                 ret = btrfs_end_transaction_nolock(trans, root);
1258                 BUG_ON(ret);
1259         } else {
1260                 ret = btrfs_end_transaction(trans, root);
1261                 BUG_ON(ret);
1262         }
1263         btrfs_free_path(path);
1264         return 0;
1265 }
1266 
1267 /*
1268  * extent_io.c call back to do delayed allocation processing
1269  */
1270 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1271                               u64 start, u64 end, int *page_started,
1272                               unsigned long *nr_written)
1273 {
1274         int ret;
1275         struct btrfs_root *root = BTRFS_I(inode)->root;
1276 
1277         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)
1278                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1279                                          page_started, 1, nr_written);
1280         else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)
1281                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1282                                          page_started, 0, nr_written);
1283         else if (!btrfs_test_opt(root, COMPRESS) &&
1284                  !(BTRFS_I(inode)->force_compress) &&
1285                  !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))
1286                 ret = cow_file_range(inode, locked_page, start, end,
1287                                       page_started, nr_written, 1);
1288         else
1289                 ret = cow_file_range_async(inode, locked_page, start, end,
1290                                            page_started, nr_written);
1291         return ret;
1292 }
1293 
1294 static int btrfs_split_extent_hook(struct inode *inode,
1295                                    struct extent_state *orig, u64 split)
1296 {
1297         /* not delalloc, ignore it */
1298         if (!(orig->state & EXTENT_DELALLOC))
1299                 return 0;
1300 
1301         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1302         return 0;
1303 }
1304 
1305 /*
1306  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1307  * extents so we can keep track of new extents that are just merged onto old
1308  * extents, such as when we are doing sequential writes, so we can properly
1309  * account for the metadata space we'll need.
1310  */
1311 static int btrfs_merge_extent_hook(struct inode *inode,
1312                                    struct extent_state *new,
1313                                    struct extent_state *other)
1314 {
1315         /* not delalloc, ignore it */
1316         if (!(other->state & EXTENT_DELALLOC))
1317                 return 0;
1318 
1319         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1320         return 0;
1321 }
1322 
1323 /*
1324  * extent_io.c set_bit_hook, used to track delayed allocation
1325  * bytes in this file, and to maintain the list of inodes that
1326  * have pending delalloc work to be done.
1327  */
1328 static int btrfs_set_bit_hook(struct inode *inode,
1329                               struct extent_state *state, int *bits)
1330 {
1331 
1332         /*
1333          * set_bit and clear bit hooks normally require _irqsave/restore
1334          * but in this case, we are only testing for the DELALLOC
1335          * bit, which is only set or cleared with irqs on
1336          */
1337         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1338                 struct btrfs_root *root = BTRFS_I(inode)->root;
1339                 u64 len = state->end + 1 - state->start;
1340                 bool do_list = !is_free_space_inode(root, inode);
1341 
1342                 if (*bits & EXTENT_FIRST_DELALLOC)
1343                         *bits &= ~EXTENT_FIRST_DELALLOC;
1344                 else
1345                         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1346 
1347                 spin_lock(&root->fs_info->delalloc_lock);
1348                 BTRFS_I(inode)->delalloc_bytes += len;
1349                 root->fs_info->delalloc_bytes += len;
1350                 if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1351                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1352                                       &root->fs_info->delalloc_inodes);
1353                 }
1354                 spin_unlock(&root->fs_info->delalloc_lock);
1355         }
1356         return 0;
1357 }
1358 
1359 /*
1360  * extent_io.c clear_bit_hook, see set_bit_hook for why
1361  */
1362 static int btrfs_clear_bit_hook(struct inode *inode,
1363                                 struct extent_state *state, int *bits)
1364 {
1365         /*
1366          * set_bit and clear bit hooks normally require _irqsave/restore
1367          * but in this case, we are only testing for the DELALLOC
1368          * bit, which is only set or cleared with irqs on
1369          */
1370         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1371                 struct btrfs_root *root = BTRFS_I(inode)->root;
1372                 u64 len = state->end + 1 - state->start;
1373                 bool do_list = !is_free_space_inode(root, inode);
1374 
1375                 if (*bits & EXTENT_FIRST_DELALLOC)
1376                         *bits &= ~EXTENT_FIRST_DELALLOC;
1377                 else if (!(*bits & EXTENT_DO_ACCOUNTING))
1378                         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1379 
1380                 if (*bits & EXTENT_DO_ACCOUNTING)
1381                         btrfs_delalloc_release_metadata(inode, len);
1382 
1383                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1384                     && do_list)
1385                         btrfs_free_reserved_data_space(inode, len);
1386 
1387                 spin_lock(&root->fs_info->delalloc_lock);
1388                 root->fs_info->delalloc_bytes -= len;
1389                 BTRFS_I(inode)->delalloc_bytes -= len;
1390 
1391                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1392                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1393                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1394                 }
1395                 spin_unlock(&root->fs_info->delalloc_lock);
1396         }
1397         return 0;
1398 }
1399 
1400 /*
1401  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1402  * we don't create bios that span stripes or chunks
1403  */
1404 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1405                          size_t size, struct bio *bio,
1406                          unsigned long bio_flags)
1407 {
1408         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1409         struct btrfs_mapping_tree *map_tree;
1410         u64 logical = (u64)bio->bi_sector << 9;
1411         u64 length = 0;
1412         u64 map_length;
1413         int ret;
1414 
1415         if (bio_flags & EXTENT_BIO_COMPRESSED)
1416                 return 0;
1417 
1418         length = bio->bi_size;
1419         map_tree = &root->fs_info->mapping_tree;
1420         map_length = length;
1421         ret = btrfs_map_block(map_tree, READ, logical,
1422                               &map_length, NULL, 0);
1423 
1424         if (map_length < length + size)
1425                 return 1;
1426         return ret;
1427 }
1428 
1429 /*
1430  * in order to insert checksums into the metadata in large chunks,
1431  * we wait until bio submission time.   All the pages in the bio are
1432  * checksummed and sums are attached onto the ordered extent record.
1433  *
1434  * At IO completion time the cums attached on the ordered extent record
1435  * are inserted into the btree
1436  */
1437 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1438                                     struct bio *bio, int mirror_num,
1439                                     unsigned long bio_flags,
1440                                     u64 bio_offset)
1441 {
1442         struct btrfs_root *root = BTRFS_I(inode)->root;
1443         int ret = 0;
1444 
1445         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1446         BUG_ON(ret);
1447         return 0;
1448 }
1449 
1450 /*
1451  * in order to insert checksums into the metadata in large chunks,
1452  * we wait until bio submission time.   All the pages in the bio are
1453  * checksummed and sums are attached onto the ordered extent record.
1454  *
1455  * At IO completion time the cums attached on the ordered extent record
1456  * are inserted into the btree
1457  */
1458 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1459                           int mirror_num, unsigned long bio_flags,
1460                           u64 bio_offset)
1461 {
1462         struct btrfs_root *root = BTRFS_I(inode)->root;
1463         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1464 }
1465 
1466 /*
1467  * extent_io.c submission hook. This does the right thing for csum calculation
1468  * on write, or reading the csums from the tree before a read
1469  */
1470 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1471                           int mirror_num, unsigned long bio_flags,
1472                           u64 bio_offset)
1473 {
1474         struct btrfs_root *root = BTRFS_I(inode)->root;
1475         int ret = 0;
1476         int skip_sum;
1477 
1478         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1479 
1480         if (is_free_space_inode(root, inode))
1481                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 2);
1482         else
1483                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1484         BUG_ON(ret);
1485 
1486         if (!(rw & REQ_WRITE)) {
1487                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1488                         return btrfs_submit_compressed_read(inode, bio,
1489                                                     mirror_num, bio_flags);
1490                 } else if (!skip_sum) {
1491                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1492                         if (ret)
1493                                 return ret;
1494                 }
1495                 goto mapit;
1496         } else if (!skip_sum) {
1497                 /* csum items have already been cloned */
1498                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1499                         goto mapit;
1500                 /* we're doing a write, do the async checksumming */
1501                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1502                                    inode, rw, bio, mirror_num,
1503                                    bio_flags, bio_offset,
1504                                    __btrfs_submit_bio_start,
1505                                    __btrfs_submit_bio_done);
1506         }
1507 
1508 mapit:
1509         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1510 }
1511 
1512 /*
1513  * given a list of ordered sums record them in the inode.  This happens
1514  * at IO completion time based on sums calculated at bio submission time.
1515  */
1516 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1517                              struct inode *inode, u64 file_offset,
1518                              struct list_head *list)
1519 {
1520         struct btrfs_ordered_sum *sum;
1521 
1522         list_for_each_entry(sum, list, list) {
1523                 btrfs_csum_file_blocks(trans,
1524                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1525         }
1526         return 0;
1527 }
1528 
1529 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1530                               struct extent_state **cached_state)
1531 {
1532         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1533                 WARN_ON(1);
1534         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1535                                    cached_state, GFP_NOFS);
1536 }
1537 
1538 /* see btrfs_writepage_start_hook for details on why this is required */
1539 struct btrfs_writepage_fixup {
1540         struct page *page;
1541         struct btrfs_work work;
1542 };
1543 
1544 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1545 {
1546         struct btrfs_writepage_fixup *fixup;
1547         struct btrfs_ordered_extent *ordered;
1548         struct extent_state *cached_state = NULL;
1549         struct page *page;
1550         struct inode *inode;
1551         u64 page_start;
1552         u64 page_end;
1553 
1554         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1555         page = fixup->page;
1556 again:
1557         lock_page(page);
1558         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1559                 ClearPageChecked(page);
1560                 goto out_page;
1561         }
1562 
1563         inode = page->mapping->host;
1564         page_start = page_offset(page);
1565         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1566 
1567         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1568                          &cached_state, GFP_NOFS);
1569 
1570         /* already ordered? We're done */
1571         if (PagePrivate2(page))
1572                 goto out;
1573 
1574         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1575         if (ordered) {
1576                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1577                                      page_end, &cached_state, GFP_NOFS);
1578                 unlock_page(page);
1579                 btrfs_start_ordered_extent(inode, ordered, 1);
1580                 goto again;
1581         }
1582 
1583         BUG();
1584         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1585         ClearPageChecked(page);
1586 out:
1587         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1588                              &cached_state, GFP_NOFS);
1589 out_page:
1590         unlock_page(page);
1591         page_cache_release(page);
1592         kfree(fixup);
1593 }
1594 
1595 /*
1596  * There are a few paths in the higher layers of the kernel that directly
1597  * set the page dirty bit without asking the filesystem if it is a
1598  * good idea.  This causes problems because we want to make sure COW
1599  * properly happens and the data=ordered rules are followed.
1600  *
1601  * In our case any range that doesn't have the ORDERED bit set
1602  * hasn't been properly setup for IO.  We kick off an async process
1603  * to fix it up.  The async helper will wait for ordered extents, set
1604  * the delalloc bit and make it safe to write the page.
1605  */
1606 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1607 {
1608         struct inode *inode = page->mapping->host;
1609         struct btrfs_writepage_fixup *fixup;
1610         struct btrfs_root *root = BTRFS_I(inode)->root;
1611 
1612         /* this page is properly in the ordered list */
1613         if (TestClearPagePrivate2(page))
1614                 return 0;
1615 
1616         if (PageChecked(page))
1617                 return -EAGAIN;
1618 
1619         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1620         if (!fixup)
1621                 return -EAGAIN;
1622 
1623         SetPageChecked(page);
1624         page_cache_get(page);
1625         fixup->work.func = btrfs_writepage_fixup_worker;
1626         fixup->page = page;
1627         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1628         return -EAGAIN;
1629 }
1630 
1631 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1632                                        struct inode *inode, u64 file_pos,
1633                                        u64 disk_bytenr, u64 disk_num_bytes,
1634                                        u64 num_bytes, u64 ram_bytes,
1635                                        u8 compression, u8 encryption,
1636                                        u16 other_encoding, int extent_type)
1637 {
1638         struct btrfs_root *root = BTRFS_I(inode)->root;
1639         struct btrfs_file_extent_item *fi;
1640         struct btrfs_path *path;
1641         struct extent_buffer *leaf;
1642         struct btrfs_key ins;
1643         u64 hint;
1644         int ret;
1645 
1646         path = btrfs_alloc_path();
1647         BUG_ON(!path);
1648 
1649         path->leave_spinning = 1;
1650 
1651         /*
1652          * we may be replacing one extent in the tree with another.
1653          * The new extent is pinned in the extent map, and we don't want
1654          * to drop it from the cache until it is completely in the btree.
1655          *
1656          * So, tell btrfs_drop_extents to leave this extent in the cache.
1657          * the caller is expected to unpin it and allow it to be merged
1658          * with the others.
1659          */
1660         ret = btrfs_drop_extents(trans, inode, file_pos, file_pos + num_bytes,
1661                                  &hint, 0);
1662         BUG_ON(ret);
1663 
1664         ins.objectid = btrfs_ino(inode);
1665         ins.offset = file_pos;
1666         ins.type = BTRFS_EXTENT_DATA_KEY;
1667         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1668         BUG_ON(ret);
1669         leaf = path->nodes[0];
1670         fi = btrfs_item_ptr(leaf, path->slots[0],
1671                             struct btrfs_file_extent_item);
1672         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1673         btrfs_set_file_extent_type(leaf, fi, extent_type);
1674         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1675         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1676         btrfs_set_file_extent_offset(leaf, fi, 0);
1677         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1678         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1679         btrfs_set_file_extent_compression(leaf, fi, compression);
1680         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1681         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1682 
1683         btrfs_unlock_up_safe(path, 1);
1684         btrfs_set_lock_blocking(leaf);
1685 
1686         btrfs_mark_buffer_dirty(leaf);
1687 
1688         inode_add_bytes(inode, num_bytes);
1689 
1690         ins.objectid = disk_bytenr;
1691         ins.offset = disk_num_bytes;
1692         ins.type = BTRFS_EXTENT_ITEM_KEY;
1693         ret = btrfs_alloc_reserved_file_extent(trans, root,
1694                                         root->root_key.objectid,
1695                                         btrfs_ino(inode), file_pos, &ins);
1696         BUG_ON(ret);
1697         btrfs_free_path(path);
1698 
1699         return 0;
1700 }
1701 
1702 /*
1703  * helper function for btrfs_finish_ordered_io, this
1704  * just reads in some of the csum leaves to prime them into ram
1705  * before we start the transaction.  It limits the amount of btree
1706  * reads required while inside the transaction.
1707  */
1708 /* as ordered data IO finishes, this gets called so we can finish
1709  * an ordered extent if the range of bytes in the file it covers are
1710  * fully written.
1711  */
1712 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1713 {
1714         struct btrfs_root *root = BTRFS_I(inode)->root;
1715         struct btrfs_trans_handle *trans = NULL;
1716         struct btrfs_ordered_extent *ordered_extent = NULL;
1717         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1718         struct extent_state *cached_state = NULL;
1719         int compress_type = 0;
1720         int ret;
1721         bool nolock;
1722 
1723         ret = btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
1724                                              end - start + 1);
1725         if (!ret)
1726                 return 0;
1727         BUG_ON(!ordered_extent);
1728 
1729         nolock = is_free_space_inode(root, inode);
1730 
1731         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
1732                 BUG_ON(!list_empty(&ordered_extent->list));
1733                 ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1734                 if (!ret) {
1735                         if (nolock)
1736                                 trans = btrfs_join_transaction_nolock(root);
1737                         else
1738                                 trans = btrfs_join_transaction(root);
1739                         BUG_ON(IS_ERR(trans));
1740                         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1741                         ret = btrfs_update_inode(trans, root, inode);
1742                         BUG_ON(ret);
1743                 }
1744                 goto out;
1745         }
1746 
1747         lock_extent_bits(io_tree, ordered_extent->file_offset,
1748                          ordered_extent->file_offset + ordered_extent->len - 1,
1749                          0, &cached_state, GFP_NOFS);
1750 
1751         if (nolock)
1752                 trans = btrfs_join_transaction_nolock(root);
1753         else
1754                 trans = btrfs_join_transaction(root);
1755         BUG_ON(IS_ERR(trans));
1756         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1757 
1758         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1759                 compress_type = ordered_extent->compress_type;
1760         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1761                 BUG_ON(compress_type);
1762                 ret = btrfs_mark_extent_written(trans, inode,
1763                                                 ordered_extent->file_offset,
1764                                                 ordered_extent->file_offset +
1765                                                 ordered_extent->len);
1766                 BUG_ON(ret);
1767         } else {
1768                 BUG_ON(root == root->fs_info->tree_root);
1769                 ret = insert_reserved_file_extent(trans, inode,
1770                                                 ordered_extent->file_offset,
1771                                                 ordered_extent->start,
1772                                                 ordered_extent->disk_len,
1773                                                 ordered_extent->len,
1774                                                 ordered_extent->len,
1775                                                 compress_type, 0, 0,
1776                                                 BTRFS_FILE_EXTENT_REG);
1777                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1778                                    ordered_extent->file_offset,
1779                                    ordered_extent->len);
1780                 BUG_ON(ret);
1781         }
1782         unlock_extent_cached(io_tree, ordered_extent->file_offset,
1783                              ordered_extent->file_offset +
1784                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
1785 
1786         add_pending_csums(trans, inode, ordered_extent->file_offset,
1787                           &ordered_extent->list);
1788 
1789         ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1790         if (!ret) {
1791                 ret = btrfs_update_inode(trans, root, inode);
1792                 BUG_ON(ret);
1793         }
1794         ret = 0;
1795 out:
1796         if (nolock) {
1797                 if (trans)
1798                         btrfs_end_transaction_nolock(trans, root);
1799         } else {
1800                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
1801                 if (trans)
1802                         btrfs_end_transaction(trans, root);
1803         }
1804 
1805         /* once for us */
1806         btrfs_put_ordered_extent(ordered_extent);
1807         /* once for the tree */
1808         btrfs_put_ordered_extent(ordered_extent);
1809 
1810         return 0;
1811 }
1812 
1813 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1814                                 struct extent_state *state, int uptodate)
1815 {
1816         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
1817 
1818         ClearPagePrivate2(page);
1819         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1820 }
1821 
1822 /*
1823  * When IO fails, either with EIO or csum verification fails, we
1824  * try other mirrors that might have a good copy of the data.  This
1825  * io_failure_record is used to record state as we go through all the
1826  * mirrors.  If another mirror has good data, the page is set up to date
1827  * and things continue.  If a good mirror can't be found, the original
1828  * bio end_io callback is called to indicate things have failed.
1829  */
1830 struct io_failure_record {
1831         struct page *page;
1832         u64 start;
1833         u64 len;
1834         u64 logical;
1835         unsigned long bio_flags;
1836         int last_mirror;
1837 };
1838 
1839 static int btrfs_io_failed_hook(struct bio *failed_bio,
1840                          struct page *page, u64 start, u64 end,
1841                          struct extent_state *state)
1842 {
1843         struct io_failure_record *failrec = NULL;
1844         u64 private;
1845         struct extent_map *em;
1846         struct inode *inode = page->mapping->host;
1847         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1848         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1849         struct bio *bio;
1850         int num_copies;
1851         int ret;
1852         int rw;
1853         u64 logical;
1854 
1855         ret = get_state_private(failure_tree, start, &private);
1856         if (ret) {
1857                 failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
1858                 if (!failrec)
1859                         return -ENOMEM;
1860                 failrec->start = start;
1861                 failrec->len = end - start + 1;
1862                 failrec->last_mirror = 0;
1863                 failrec->bio_flags = 0;
1864 
1865                 read_lock(&em_tree->lock);
1866                 em = lookup_extent_mapping(em_tree, start, failrec->len);
1867                 if (em->start > start || em->start + em->len < start) {
1868                         free_extent_map(em);
1869                         em = NULL;
1870                 }
1871                 read_unlock(&em_tree->lock);
1872 
1873                 if (IS_ERR_OR_NULL(em)) {
1874                         kfree(failrec);
1875                         return -EIO;
1876                 }
1877                 logical = start - em->start;
1878                 logical = em->block_start + logical;
1879                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1880                         logical = em->block_start;
1881                         failrec->bio_flags = EXTENT_BIO_COMPRESSED;
1882                         extent_set_compress_type(&failrec->bio_flags,
1883                                                  em->compress_type);
1884                 }
1885                 failrec->logical = logical;
1886                 free_extent_map(em);
1887                 set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
1888                                 EXTENT_DIRTY, GFP_NOFS);
1889                 set_state_private(failure_tree, start,
1890                                  (u64)(unsigned long)failrec);
1891         } else {
1892                 failrec = (struct io_failure_record *)(unsigned long)private;
1893         }
1894         num_copies = btrfs_num_copies(
1895                               &BTRFS_I(inode)->root->fs_info->mapping_tree,
1896                               failrec->logical, failrec->len);
1897         failrec->last_mirror++;
1898         if (!state) {
1899                 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1900                 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1901                                                     failrec->start,
1902                                                     EXTENT_LOCKED);
1903                 if (state && state->start != failrec->start)
1904                         state = NULL;
1905                 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1906         }
1907         if (!state || failrec->last_mirror > num_copies) {
1908                 set_state_private(failure_tree, failrec->start, 0);
1909                 clear_extent_bits(failure_tree, failrec->start,
1910                                   failrec->start + failrec->len - 1,
1911                                   EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1912                 kfree(failrec);
1913                 return -EIO;
1914         }
1915         bio = bio_alloc(GFP_NOFS, 1);
1916         bio->bi_private = state;
1917         bio->bi_end_io = failed_bio->bi_end_io;
1918         bio->bi_sector = failrec->logical >> 9;
1919         bio->bi_bdev = failed_bio->bi_bdev;
1920         bio->bi_size = 0;
1921 
1922         bio_add_page(bio, page, failrec->len, start - page_offset(page));
1923         if (failed_bio->bi_rw & REQ_WRITE)
1924                 rw = WRITE;
1925         else
1926                 rw = READ;
1927 
1928         ret = BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
1929                                                       failrec->last_mirror,
1930                                                       failrec->bio_flags, 0);
1931         return ret;
1932 }
1933 
1934 /*
1935  * each time an IO finishes, we do a fast check in the IO failure tree
1936  * to see if we need to process or clean up an io_failure_record
1937  */
1938 static int btrfs_clean_io_failures(struct inode *inode, u64 start)
1939 {
1940         u64 private;
1941         u64 private_failure;
1942         struct io_failure_record *failure;
1943         int ret;
1944 
1945         private = 0;
1946         if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1947                              (u64)-1, 1, EXTENT_DIRTY, 0)) {
1948                 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
1949                                         start, &private_failure);
1950                 if (ret == 0) {
1951                         failure = (struct io_failure_record *)(unsigned long)
1952                                    private_failure;
1953                         set_state_private(&BTRFS_I(inode)->io_failure_tree,
1954                                           failure->start, 0);
1955                         clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
1956                                           failure->start,
1957                                           failure->start + failure->len - 1,
1958                                           EXTENT_DIRTY | EXTENT_LOCKED,
1959                                           GFP_NOFS);
1960                         kfree(failure);
1961                 }
1962         }
1963         return 0;
1964 }
1965 
1966 /*
1967  * when reads are done, we need to check csums to verify the data is correct
1968  * if there's a match, we allow the bio to finish.  If not, we go through
1969  * the io_failure_record routines to find good copies
1970  */
1971 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1972                                struct extent_state *state)
1973 {
1974         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1975         struct inode *inode = page->mapping->host;
1976         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1977         char *kaddr;
1978         u64 private = ~(u32)0;
1979         int ret;
1980         struct btrfs_root *root = BTRFS_I(inode)->root;
1981         u32 csum = ~(u32)0;
1982 
1983         if (PageChecked(page)) {
1984                 ClearPageChecked(page);
1985                 goto good;
1986         }
1987 
1988         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
1989                 goto good;
1990 
1991         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1992             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
1993                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1994                                   GFP_NOFS);
1995                 return 0;
1996         }
1997 
1998         if (state && state->start == start) {
1999                 private = state->private;
2000                 ret = 0;
2001         } else {
2002                 ret = get_state_private(io_tree, start, &private);
2003         }
2004         kaddr = kmap_atomic(page, KM_USER0);
2005         if (ret)
2006                 goto zeroit;
2007 
2008         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
2009         btrfs_csum_final(csum, (char *)&csum);
2010         if (csum != private)
2011                 goto zeroit;
2012 
2013         kunmap_atomic(kaddr, KM_USER0);
2014 good:
2015         /* if the io failure tree for this inode is non-empty,
2016          * check to see if we've recovered from a failed IO
2017          */
2018         btrfs_clean_io_failures(inode, start);
2019         return 0;
2020 
2021 zeroit:
2022         printk_ratelimited(KERN_INFO "btrfs csum failed ino %llu off %llu csum %u "
2023                        "private %llu\n",
2024                        (unsigned long long)btrfs_ino(page->mapping->host),
2025                        (unsigned long long)start, csum,
2026                        (unsigned long long)private);
2027         memset(kaddr + offset, 1, end - start + 1);
2028         flush_dcache_page(page);
2029         kunmap_atomic(kaddr, KM_USER0);
2030         if (private == 0)
2031                 return 0;
2032         return -EIO;
2033 }
2034 
2035 struct delayed_iput {
2036         struct list_head list;
2037         struct inode *inode;
2038 };
2039 
2040 void btrfs_add_delayed_iput(struct inode *inode)
2041 {
2042         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2043         struct delayed_iput *delayed;
2044 
2045         if (atomic_add_unless(&inode->i_count, -1, 1))
2046                 return;
2047 
2048         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2049         delayed->inode = inode;
2050 
2051         spin_lock(&fs_info->delayed_iput_lock);
2052         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2053         spin_unlock(&fs_info->delayed_iput_lock);
2054 }
2055 
2056 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2057 {
2058         LIST_HEAD(list);
2059         struct btrfs_fs_info *fs_info = root->fs_info;
2060         struct delayed_iput *delayed;
2061         int empty;
2062 
2063         spin_lock(&fs_info->delayed_iput_lock);
2064         empty = list_empty(&fs_info->delayed_iputs);
2065         spin_unlock(&fs_info->delayed_iput_lock);
2066         if (empty)
2067                 return;
2068 
2069         down_read(&root->fs_info->cleanup_work_sem);
2070         spin_lock(&fs_info->delayed_iput_lock);
2071         list_splice_init(&fs_info->delayed_iputs, &list);
2072         spin_unlock(&fs_info->delayed_iput_lock);
2073 
2074         while (!list_empty(&list)) {
2075                 delayed = list_entry(list.next, struct delayed_iput, list);
2076                 list_del(&delayed->list);
2077                 iput(delayed->inode);
2078                 kfree(delayed);
2079         }
2080         up_read(&root->fs_info->cleanup_work_sem);
2081 }
2082 
2083 /*
2084  * calculate extra metadata reservation when snapshotting a subvolume
2085  * contains orphan files.
2086  */
2087 void btrfs_orphan_pre_snapshot(struct btrfs_trans_handle *trans,
2088                                 struct btrfs_pending_snapshot *pending,
2089                                 u64 *bytes_to_reserve)
2090 {
2091         struct btrfs_root *root;
2092         struct btrfs_block_rsv *block_rsv;
2093         u64 num_bytes;
2094         int index;
2095 
2096         root = pending->root;
2097         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2098                 return;
2099 
2100         block_rsv = root->orphan_block_rsv;
2101 
2102         /* orphan block reservation for the snapshot */
2103         num_bytes = block_rsv->size;
2104 
2105         /*
2106          * after the snapshot is created, COWing tree blocks may use more
2107          * space than it frees. So we should make sure there is enough
2108          * reserved space.
2109          */
2110         index = trans->transid & 0x1;
2111         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2112                 num_bytes += block_rsv->size -
2113                              (block_rsv->reserved + block_rsv->freed[index]);
2114         }
2115 
2116         *bytes_to_reserve += num_bytes;
2117 }
2118 
2119 void btrfs_orphan_post_snapshot(struct btrfs_trans_handle *trans,
2120                                 struct btrfs_pending_snapshot *pending)
2121 {
2122         struct btrfs_root *root = pending->root;
2123         struct btrfs_root *snap = pending->snap;
2124         struct btrfs_block_rsv *block_rsv;
2125         u64 num_bytes;
2126         int index;
2127         int ret;
2128 
2129         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2130                 return;
2131 
2132         /* refill source subvolume's orphan block reservation */
2133         block_rsv = root->orphan_block_rsv;
2134         index = trans->transid & 0x1;
2135         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2136                 num_bytes = block_rsv->size -
2137                             (block_rsv->reserved + block_rsv->freed[index]);
2138                 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2139                                               root->orphan_block_rsv,
2140                                               num_bytes);
2141                 BUG_ON(ret);
2142         }
2143 
2144         /* setup orphan block reservation for the snapshot */
2145         block_rsv = btrfs_alloc_block_rsv(snap);
2146         BUG_ON(!block_rsv);
2147 
2148         btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2149         snap->orphan_block_rsv = block_rsv;
2150 
2151         num_bytes = root->orphan_block_rsv->size;
2152         ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2153                                       block_rsv, num_bytes);
2154         BUG_ON(ret);
2155 
2156 #if 0
2157         /* insert orphan item for the snapshot */
2158         WARN_ON(!root->orphan_item_inserted);
2159         ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2160                                        snap->root_key.objectid);
2161         BUG_ON(ret);
2162         snap->orphan_item_inserted = 1;
2163 #endif
2164 }
2165 
2166 enum btrfs_orphan_cleanup_state {
2167         ORPHAN_CLEANUP_STARTED  = 1,
2168         ORPHAN_CLEANUP_DONE     = 2,
2169 };
2170 
2171 /*
2172  * This is called in transaction commmit time. If there are no orphan
2173  * files in the subvolume, it removes orphan item and frees block_rsv
2174  * structure.
2175  */
2176 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2177                               struct btrfs_root *root)
2178 {
2179         int ret;
2180 
2181         if (!list_empty(&root->orphan_list) ||
2182             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2183                 return;
2184 
2185         if (root->orphan_item_inserted &&
2186             btrfs_root_refs(&root->root_item) > 0) {
2187                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2188                                             root->root_key.objectid);
2189                 BUG_ON(ret);
2190                 root->orphan_item_inserted = 0;
2191         }
2192 
2193         if (root->orphan_block_rsv) {
2194                 WARN_ON(root->orphan_block_rsv->size > 0);
2195                 btrfs_free_block_rsv(root, root->orphan_block_rsv);
2196                 root->orphan_block_rsv = NULL;
2197         }
2198 }
2199 
2200 /*
2201  * This creates an orphan entry for the given inode in case something goes
2202  * wrong in the middle of an unlink/truncate.
2203  *
2204  * NOTE: caller of this function should reserve 5 units of metadata for
2205  *       this function.
2206  */
2207 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2208 {
2209         struct btrfs_root *root = BTRFS_I(inode)->root;
2210         struct btrfs_block_rsv *block_rsv = NULL;
2211         int reserve = 0;
2212         int insert = 0;
2213         int ret;
2214 
2215         if (!root->orphan_block_rsv) {
2216                 block_rsv = btrfs_alloc_block_rsv(root);
2217                 BUG_ON(!block_rsv);
2218         }
2219 
2220         spin_lock(&root->orphan_lock);
2221         if (!root->orphan_block_rsv) {
2222                 root->orphan_block_rsv = block_rsv;
2223         } else if (block_rsv) {
2224                 btrfs_free_block_rsv(root, block_rsv);
2225                 block_rsv = NULL;
2226         }
2227 
2228         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
2229                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2230 #if 0
2231                 /*
2232                  * For proper ENOSPC handling, we should do orphan
2233                  * cleanup when mounting. But this introduces backward
2234                  * compatibility issue.
2235                  */
2236                 if (!xchg(&root->orphan_item_inserted, 1))
2237                         insert = 2;
2238                 else
2239                         insert = 1;
2240 #endif
2241                 insert = 1;
2242         }
2243 
2244         if (!BTRFS_I(inode)->orphan_meta_reserved) {
2245                 BTRFS_I(inode)->orphan_meta_reserved = 1;
2246                 reserve = 1;
2247         }
2248         spin_unlock(&root->orphan_lock);
2249 
2250         if (block_rsv)
2251                 btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2252 
2253         /* grab metadata reservation from transaction handle */
2254         if (reserve) {
2255                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2256                 BUG_ON(ret);
2257         }
2258 
2259         /* insert an orphan item to track this unlinked/truncated file */
2260         if (insert >= 1) {
2261                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
2262                 BUG_ON(ret);
2263         }
2264 
2265         /* insert an orphan item to track subvolume contains orphan files */
2266         if (insert >= 2) {
2267                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2268                                                root->root_key.objectid);
2269                 BUG_ON(ret);
2270         }
2271         return 0;
2272 }
2273 
2274 /*
2275  * We have done the truncate/delete so we can go ahead and remove the orphan
2276  * item for this particular inode.
2277  */
2278 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2279 {
2280         struct btrfs_root *root = BTRFS_I(inode)->root;
2281         int delete_item = 0;
2282         int release_rsv = 0;
2283         int ret = 0;
2284 
2285         spin_lock(&root->orphan_lock);
2286         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
2287                 list_del_init(&BTRFS_I(inode)->i_orphan);
2288                 delete_item = 1;
2289         }
2290 
2291         if (BTRFS_I(inode)->orphan_meta_reserved) {
2292                 BTRFS_I(inode)->orphan_meta_reserved = 0;
2293                 release_rsv = 1;
2294         }
2295         spin_unlock(&root->orphan_lock);
2296 
2297         if (trans && delete_item) {
2298                 ret = btrfs_del_orphan_item(trans, root, btrfs_ino(inode));
2299                 BUG_ON(ret);
2300         }
2301 
2302         if (release_rsv)
2303                 btrfs_orphan_release_metadata(inode);
2304 
2305         return 0;
2306 }
2307 
2308 /*
2309  * this cleans up any orphans that may be left on the list from the last use
2310  * of this root.
2311  */
2312 int btrfs_orphan_cleanup(struct btrfs_root *root)
2313 {
2314         struct btrfs_path *path;
2315         struct extent_buffer *leaf;
2316         struct btrfs_key key, found_key;
2317         struct btrfs_trans_handle *trans;
2318         struct inode *inode;
2319         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2320 
2321         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
2322                 return 0;
2323 
2324         path = btrfs_alloc_path();
2325         if (!path) {
2326                 ret = -ENOMEM;
2327                 goto out;
2328         }
2329         path->reada = -1;
2330 
2331         key.objectid = BTRFS_ORPHAN_OBJECTID;
2332         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2333         key.offset = (u64)-1;
2334 
2335         while (1) {
2336                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2337                 if (ret < 0)
2338                         goto out;
2339 
2340                 /*
2341                  * if ret == 0 means we found what we were searching for, which
2342                  * is weird, but possible, so only screw with path if we didn't
2343                  * find the key and see if we have stuff that matches
2344                  */
2345                 if (ret > 0) {
2346                         ret = 0;
2347                         if (path->slots[0] == 0)
2348                                 break;
2349                         path->slots[0]--;
2350                 }
2351 
2352                 /* pull out the item */
2353                 leaf = path->nodes[0];
2354                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2355 
2356                 /* make sure the item matches what we want */
2357                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2358                         break;
2359                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2360                         break;
2361 
2362                 /* release the path since we're done with it */
2363                 btrfs_release_path(path);
2364 
2365                 /*
2366                  * this is where we are basically btrfs_lookup, without the
2367                  * crossing root thing.  we store the inode number in the
2368                  * offset of the orphan item.
2369                  */
2370                 found_key.objectid = found_key.offset;
2371                 found_key.type = BTRFS_INODE_ITEM_KEY;
2372                 found_key.offset = 0;
2373                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
2374                 if (IS_ERR(inode)) {
2375                         ret = PTR_ERR(inode);
2376                         goto out;
2377                 }
2378 
2379                 /*
2380                  * add this inode to the orphan list so btrfs_orphan_del does
2381                  * the proper thing when we hit it
2382                  */
2383                 spin_lock(&root->orphan_lock);
2384                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2385                 spin_unlock(&root->orphan_lock);
2386 
2387                 /*
2388                  * if this is a bad inode, means we actually succeeded in
2389                  * removing the inode, but not the orphan record, which means
2390                  * we need to manually delete the orphan since iput will just
2391                  * do a destroy_inode
2392                  */
2393                 if (is_bad_inode(inode)) {
2394                         trans = btrfs_start_transaction(root, 0);
2395                         if (IS_ERR(trans)) {
2396                                 ret = PTR_ERR(trans);
2397                                 goto out;
2398                         }
2399                         btrfs_orphan_del(trans, inode);
2400                         btrfs_end_transaction(trans, root);
2401                         iput(inode);
2402                         continue;
2403                 }
2404 
2405                 /* if we have links, this was a truncate, lets do that */
2406                 if (inode->i_nlink) {
2407                         if (!S_ISREG(inode->i_mode)) {
2408                                 WARN_ON(1);
2409                                 iput(inode);
2410                                 continue;
2411                         }
2412                         nr_truncate++;
2413                         ret = btrfs_truncate(inode);
2414                 } else {
2415                         nr_unlink++;
2416                 }
2417 
2418                 /* this will do delete_inode and everything for us */
2419                 iput(inode);
2420                 if (ret)
2421                         goto out;
2422         }
2423         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
2424 
2425         if (root->orphan_block_rsv)
2426                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
2427                                         (u64)-1);
2428 
2429         if (root->orphan_block_rsv || root->orphan_item_inserted) {
2430                 trans = btrfs_join_transaction(root);
2431                 if (!IS_ERR(trans))
2432                         btrfs_end_transaction(trans, root);
2433         }
2434 
2435         if (nr_unlink)
2436                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2437         if (nr_truncate)
2438                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2439 
2440 out:
2441         if (ret)
2442                 printk(KERN_CRIT "btrfs: could not do orphan cleanup %d\n", ret);
2443         btrfs_free_path(path);
2444         return ret;
2445 }
2446 
2447 /*
2448  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2449  * don't find any xattrs, we know there can't be any acls.
2450  *
2451  * slot is the slot the inode is in, objectid is the objectid of the inode
2452  */
2453 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2454                                           int slot, u64 objectid)
2455 {
2456         u32 nritems = btrfs_header_nritems(leaf);
2457         struct btrfs_key found_key;
2458         int scanned = 0;
2459 
2460         slot++;
2461         while (slot < nritems) {
2462                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2463 
2464                 /* we found a different objectid, there must not be acls */
2465                 if (found_key.objectid != objectid)
2466                         return 0;
2467 
2468                 /* we found an xattr, assume we've got an acl */
2469                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2470                         return 1;
2471 
2472                 /*
2473                  * we found a key greater than an xattr key, there can't
2474                  * be any acls later on
2475                  */
2476                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2477                         return 0;
2478 
2479                 slot++;
2480                 scanned++;
2481 
2482                 /*
2483                  * it goes inode, inode backrefs, xattrs, extents,
2484                  * so if there are a ton of hard links to an inode there can
2485                  * be a lot of backrefs.  Don't waste time searching too hard,
2486                  * this is just an optimization
2487                  */
2488                 if (scanned >= 8)
2489                         break;
2490         }
2491         /* we hit the end of the leaf before we found an xattr or
2492          * something larger than an xattr.  We have to assume the inode
2493          * has acls
2494          */
2495         return 1;
2496 }
2497 
2498 /*
2499  * read an inode from the btree into the in-memory inode
2500  */
2501 static void btrfs_read_locked_inode(struct inode *inode)
2502 {
2503         struct btrfs_path *path;
2504         struct extent_buffer *leaf;
2505         struct btrfs_inode_item *inode_item;
2506         struct btrfs_timespec *tspec;
2507         struct btrfs_root *root = BTRFS_I(inode)->root;
2508         struct btrfs_key location;
2509         int maybe_acls;
2510         u32 rdev;
2511         int ret;
2512         bool filled = false;
2513 
2514         ret = btrfs_fill_inode(inode, &rdev);
2515         if (!ret)
2516                 filled = true;
2517 
2518         path = btrfs_alloc_path();
2519         BUG_ON(!path);
2520         path->leave_spinning = 1;
2521         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2522 
2523         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2524         if (ret)
2525                 goto make_bad;
2526 
2527         leaf = path->nodes[0];
2528 
2529         if (filled)
2530                 goto cache_acl;
2531 
2532         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2533                                     struct btrfs_inode_item);
2534         if (!leaf->map_token)
2535                 map_private_extent_buffer(leaf, (unsigned long)inode_item,
2536                                           sizeof(struct btrfs_inode_item),
2537                                           &leaf->map_token, &leaf->kaddr,
2538                                           &leaf->map_start, &leaf->map_len,
2539                                           KM_USER1);
2540 
2541         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2542         inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
2543         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2544         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2545         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2546 
2547         tspec = btrfs_inode_atime(inode_item);
2548         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2549         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2550 
2551         tspec = btrfs_inode_mtime(inode_item);
2552         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2553         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2554 
2555         tspec = btrfs_inode_ctime(inode_item);
2556         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2557         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2558 
2559         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2560         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2561         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2562         inode->i_generation = BTRFS_I(inode)->generation;
2563         inode->i_rdev = 0;
2564         rdev = btrfs_inode_rdev(leaf, inode_item);
2565 
2566         BTRFS_I(inode)->index_cnt = (u64)-1;
2567         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2568 cache_acl:
2569         /*
2570          * try to precache a NULL acl entry for files that don't have
2571          * any xattrs or acls
2572          */
2573         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
2574                                            btrfs_ino(inode));
2575         if (!maybe_acls)
2576                 cache_no_acl(inode);
2577 
2578         if (leaf->map_token) {
2579                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2580                 leaf->map_token = NULL;
2581         }
2582 
2583         btrfs_free_path(path);
2584 
2585         switch (inode->i_mode & S_IFMT) {
2586         case S_IFREG:
2587                 inode->i_mapping->a_ops = &btrfs_aops;
2588                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2589                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2590                 inode->i_fop = &btrfs_file_operations;
2591                 inode->i_op = &btrfs_file_inode_operations;
2592                 break;
2593         case S_IFDIR:
2594                 inode->i_fop = &btrfs_dir_file_operations;
2595                 if (root == root->fs_info->tree_root)
2596                         inode->i_op = &btrfs_dir_ro_inode_operations;
2597                 else
2598                         inode->i_op = &btrfs_dir_inode_operations;
2599                 break;
2600         case S_IFLNK:
2601                 inode->i_op = &btrfs_symlink_inode_operations;
2602                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2603                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2604                 break;
2605         default:
2606                 inode->i_op = &btrfs_special_inode_operations;
2607                 init_special_inode(inode, inode->i_mode, rdev);
2608                 break;
2609         }
2610 
2611         btrfs_update_iflags(inode);
2612         return;
2613 
2614 make_bad:
2615         btrfs_free_path(path);
2616         make_bad_inode(inode);
2617 }
2618 
2619 /*
2620  * given a leaf and an inode, copy the inode fields into the leaf
2621  */
2622 static void fill_inode_item(struct btrfs_trans_handle *trans,
2623                             struct extent_buffer *leaf,
2624                             struct btrfs_inode_item *item,
2625                             struct inode *inode)
2626 {
2627         if (!leaf->map_token)
2628                 map_private_extent_buffer(leaf, (unsigned long)item,
2629                                           sizeof(struct btrfs_inode_item),
2630                                           &leaf->map_token, &leaf->kaddr,
2631                                           &leaf->map_start, &leaf->map_len,
2632                                           KM_USER1);
2633 
2634         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2635         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2636         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2637         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2638         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2639 
2640         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2641                                inode->i_atime.tv_sec);
2642         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2643                                 inode->i_atime.tv_nsec);
2644 
2645         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2646                                inode->i_mtime.tv_sec);
2647         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2648                                 inode->i_mtime.tv_nsec);
2649 
2650         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2651                                inode->i_ctime.tv_sec);
2652         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2653                                 inode->i_ctime.tv_nsec);
2654 
2655         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2656         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2657         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2658         btrfs_set_inode_transid(leaf, item, trans->transid);
2659         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2660         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2661         btrfs_set_inode_block_group(leaf, item, 0);
2662 
2663         if (leaf->map_token) {
2664                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2665                 leaf->map_token = NULL;
2666         }
2667 }
2668 
2669 /*
2670  * copy everything in the in-memory inode into the btree.
2671  */
2672 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2673                                 struct btrfs_root *root, struct inode *inode)
2674 {
2675         struct btrfs_inode_item *inode_item;
2676         struct btrfs_path *path;
2677         struct extent_buffer *leaf;
2678         int ret;
2679 
2680         /*
2681          * If the inode is a free space inode, we can deadlock during commit
2682          * if we put it into the delayed code.
2683          *
2684          * The data relocation inode should also be directly updated
2685          * without delay
2686          */
2687         if (!is_free_space_inode(root, inode)
2688             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
2689                 ret = btrfs_delayed_update_inode(trans, root, inode);
2690                 if (!ret)
2691                         btrfs_set_inode_last_trans(trans, inode);
2692                 return ret;
2693         }
2694 
2695         path = btrfs_alloc_path();
2696         if (!path)
2697                 return -ENOMEM;
2698 
2699         path->leave_spinning = 1;
2700         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
2701                                  1);
2702         if (ret) {
2703                 if (ret > 0)
2704                         ret = -ENOENT;
2705                 goto failed;
2706         }
2707 
2708         btrfs_unlock_up_safe(path, 1);
2709         leaf = path->nodes[0];
2710         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2711                                     struct btrfs_inode_item);
2712 
2713         fill_inode_item(trans, leaf, inode_item, inode);
2714         btrfs_mark_buffer_dirty(leaf);
2715         btrfs_set_inode_last_trans(trans, inode);
2716         ret = 0;
2717 failed:
2718         btrfs_free_path(path);
2719         return ret;
2720 }
2721 
2722 /*
2723  * unlink helper that gets used here in inode.c and in the tree logging
2724  * recovery code.  It remove a link in a directory with a given name, and
2725  * also drops the back refs in the inode to the directory
2726  */
2727 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2728                                 struct btrfs_root *root,
2729                                 struct inode *dir, struct inode *inode,
2730                                 const char *name, int name_len)
2731 {
2732         struct btrfs_path *path;
2733         int ret = 0;
2734         struct extent_buffer *leaf;
2735         struct btrfs_dir_item *di;
2736         struct btrfs_key key;
2737         u64 index;
2738         u64 ino = btrfs_ino(inode);
2739         u64 dir_ino = btrfs_ino(dir);
2740 
2741         path = btrfs_alloc_path();
2742         if (!path) {
2743                 ret = -ENOMEM;
2744                 goto out;
2745         }
2746 
2747         path->leave_spinning = 1;
2748         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2749                                     name, name_len, -1);
2750         if (IS_ERR(di)) {
2751                 ret = PTR_ERR(di);
2752                 goto err;
2753         }
2754         if (!di) {
2755                 ret = -ENOENT;
2756                 goto err;
2757         }
2758         leaf = path->nodes[0];
2759         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2760         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2761         if (ret)
2762                 goto err;
2763         btrfs_release_path(path);
2764 
2765         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
2766                                   dir_ino, &index);
2767         if (ret) {
2768                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2769                        "inode %llu parent %llu\n", name_len, name,
2770                        (unsigned long long)ino, (unsigned long long)dir_ino);
2771                 goto err;
2772         }
2773 
2774         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
2775         if (ret)
2776                 goto err;
2777 
2778         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2779                                          inode, dir_ino);
2780         BUG_ON(ret != 0 && ret != -ENOENT);
2781 
2782         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2783                                            dir, index);
2784         if (ret == -ENOENT)
2785                 ret = 0;
2786 err:
2787         btrfs_free_path(path);
2788         if (ret)
2789                 goto out;
2790 
2791         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2792         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2793         btrfs_update_inode(trans, root, dir);
2794 out:
2795         return ret;
2796 }
2797 
2798 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2799                        struct btrfs_root *root,
2800                        struct inode *dir, struct inode *inode,
2801                        const char *name, int name_len)
2802 {
2803         int ret;
2804         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
2805         if (!ret) {
2806                 btrfs_drop_nlink(inode);
2807                 ret = btrfs_update_inode(trans, root, inode);
2808         }
2809         return ret;
2810 }
2811                 
2812 
2813 /* helper to check if there is any shared block in the path */
2814 static int check_path_shared(struct btrfs_root *root,
2815                              struct btrfs_path *path)
2816 {
2817         struct extent_buffer *eb;
2818         int level;
2819         u64 refs = 1;
2820 
2821         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2822                 int ret;
2823 
2824                 if (!path->nodes[level])
2825                         break;
2826                 eb = path->nodes[level];
2827                 if (!btrfs_block_can_be_shared(root, eb))
2828                         continue;
2829                 ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2830                                                &refs, NULL);
2831                 if (refs > 1)
2832                         return 1;
2833         }
2834         return 0;
2835 }
2836 
2837 /*
2838  * helper to start transaction for unlink and rmdir.
2839  *
2840  * unlink and rmdir are special in btrfs, they do not always free space.
2841  * so in enospc case, we should make sure they will free space before
2842  * allowing them to use the global metadata reservation.
2843  */
2844 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2845                                                        struct dentry *dentry)
2846 {
2847         struct btrfs_trans_handle *trans;
2848         struct btrfs_root *root = BTRFS_I(dir)->root;
2849         struct btrfs_path *path;
2850         struct btrfs_inode_ref *ref;
2851         struct btrfs_dir_item *di;
2852         struct inode *inode = dentry->d_inode;
2853         u64 index;
2854         int check_link = 1;
2855         int err = -ENOSPC;
2856         int ret;
2857         u64 ino = btrfs_ino(inode);
2858         u64 dir_ino = btrfs_ino(dir);
2859 
2860         trans = btrfs_start_transaction(root, 10);
2861         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2862                 return trans;
2863 
2864         if (ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
2865                 return ERR_PTR(-ENOSPC);
2866 
2867         /* check if there is someone else holds reference */
2868         if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2869                 return ERR_PTR(-ENOSPC);
2870 
2871         if (atomic_read(&inode->i_count) > 2)
2872                 return ERR_PTR(-ENOSPC);
2873 
2874         if (xchg(&root->fs_info->enospc_unlink, 1))
2875                 return ERR_PTR(-ENOSPC);
2876 
2877         path = btrfs_alloc_path();
2878         if (!path) {
2879                 root->fs_info->enospc_unlink = 0;
2880                 return ERR_PTR(-ENOMEM);
2881         }
2882 
2883         trans = btrfs_start_transaction(root, 0);
2884         if (IS_ERR(trans)) {
2885                 btrfs_free_path(path);
2886                 root->fs_info->enospc_unlink = 0;
2887                 return trans;
2888         }
2889 
2890         path->skip_locking = 1;
2891         path->search_commit_root = 1;
2892 
2893         ret = btrfs_lookup_inode(trans, root, path,
2894                                 &BTRFS_I(dir)->location, 0);
2895         if (ret < 0) {
2896                 err = ret;
2897                 goto out;
2898         }
2899         if (ret == 0) {
2900                 if (check_path_shared(root, path))
2901                         goto out;
2902         } else {
2903                 check_link = 0;
2904         }
2905         btrfs_release_path(path);
2906 
2907         ret = btrfs_lookup_inode(trans, root, path,
2908                                 &BTRFS_I(inode)->location, 0);
2909         if (ret < 0) {
2910                 err = ret;
2911                 goto out;
2912         }
2913         if (ret == 0) {
2914                 if (check_path_shared(root, path))
2915                         goto out;
2916         } else {
2917                 check_link = 0;
2918         }
2919         btrfs_release_path(path);
2920 
2921         if (ret == 0 && S_ISREG(inode->i_mode)) {
2922                 ret = btrfs_lookup_file_extent(trans, root, path,
2923                                                ino, (u64)-1, 0);
2924                 if (ret < 0) {
2925                         err = ret;
2926                         goto out;
2927                 }
2928                 BUG_ON(ret == 0);
2929                 if (check_path_shared(root, path))
2930                         goto out;
2931                 btrfs_release_path(path);
2932         }
2933 
2934         if (!check_link) {
2935                 err = 0;
2936                 goto out;
2937         }
2938 
2939         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2940                                 dentry->d_name.name, dentry->d_name.len, 0);
2941         if (IS_ERR(di)) {
2942                 err = PTR_ERR(di);
2943                 goto out;
2944         }
2945         if (di) {
2946                 if (check_path_shared(root, path))
2947                         goto out;
2948         } else {
2949                 err = 0;
2950                 goto out;
2951         }
2952         btrfs_release_path(path);
2953 
2954         ref = btrfs_lookup_inode_ref(trans, root, path,
2955                                 dentry->d_name.name, dentry->d_name.len,
2956                                 ino, dir_ino, 0);
2957         if (IS_ERR(ref)) {
2958                 err = PTR_ERR(ref);
2959                 goto out;
2960         }
2961         BUG_ON(!ref);
2962         if (check_path_shared(root, path))
2963                 goto out;
2964         index = btrfs_inode_ref_index(path->nodes[0], ref);
2965         btrfs_release_path(path);
2966 
2967         /*
2968          * This is a commit root search, if we can lookup inode item and other
2969          * relative items in the commit root, it means the transaction of
2970          * dir/file creation has been committed, and the dir index item that we
2971          * delay to insert has also been inserted into the commit root. So
2972          * we needn't worry about the delayed insertion of the dir index item
2973          * here.
2974          */
2975         di = btrfs_lookup_dir_index_item(trans, root, path, dir_ino, index,
2976                                 dentry->d_name.name, dentry->d_name.len, 0);
2977         if (IS_ERR(di)) {
2978                 err = PTR_ERR(di);
2979                 goto out;
2980         }
2981         BUG_ON(ret == -ENOENT);
2982         if (check_path_shared(root, path))
2983                 goto out;
2984 
2985         err = 0;
2986 out:
2987         btrfs_free_path(path);
2988         if (err) {
2989                 btrfs_end_transaction(trans, root);
2990                 root->fs_info->enospc_unlink = 0;
2991                 return ERR_PTR(err);
2992         }
2993 
2994         trans->block_rsv = &root->fs_info->global_block_rsv;
2995         return trans;
2996 }
2997 
2998 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
2999                                struct btrfs_root *root)
3000 {
3001         if (trans->block_rsv == &root->fs_info->global_block_rsv) {
3002                 BUG_ON(!root->fs_info->enospc_unlink);
3003                 root->fs_info->enospc_unlink = 0;
3004         }
3005         btrfs_end_transaction_throttle(trans, root);
3006 }
3007 
3008 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3009 {
3010         struct btrfs_root *root = BTRFS_I(dir)->root;
3011         struct btrfs_trans_handle *trans;
3012         struct inode *inode = dentry->d_inode;
3013         int ret;
3014         unsigned long nr = 0;
3015 
3016         trans = __unlink_start_trans(dir, dentry);
3017         if (IS_ERR(trans))
3018                 return PTR_ERR(trans);
3019 
3020         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3021 
3022         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3023                                  dentry->d_name.name, dentry->d_name.len);
3024         BUG_ON(ret);
3025 
3026         if (inode->i_nlink == 0) {
3027                 ret = btrfs_orphan_add(trans, inode);
3028                 BUG_ON(ret);
3029         }
3030 
3031         nr = trans->blocks_used;
3032         __unlink_end_trans(trans, root);
3033         btrfs_btree_balance_dirty(root, nr);
3034         return ret;
3035 }
3036 
3037 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3038                         struct btrfs_root *root,
3039                         struct inode *dir, u64 objectid,
3040                         const char *name, int name_len)
3041 {
3042         struct btrfs_path *path;
3043         struct extent_buffer *leaf;
3044         struct btrfs_dir_item *di;
3045         struct btrfs_key key;
3046         u64 index;
3047         int ret;
3048         u64 dir_ino = btrfs_ino(dir);
3049 
3050         path = btrfs_alloc_path();
3051         if (!path)
3052                 return -ENOMEM;
3053 
3054         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3055                                    name, name_len, -1);
3056         BUG_ON(IS_ERR_OR_NULL(di));
3057 
3058         leaf = path->nodes[0];
3059         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3060         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3061         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3062         BUG_ON(ret);
3063         btrfs_release_path(path);
3064 
3065         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3066                                  objectid, root->root_key.objectid,
3067                                  dir_ino, &index, name, name_len);
3068         if (ret < 0) {
3069                 BUG_ON(ret != -ENOENT);
3070                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3071                                                  name, name_len);
3072                 BUG_ON(IS_ERR_OR_NULL(di));
3073 
3074                 leaf = path->nodes[0];
3075                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3076                 btrfs_release_path(path);
3077                 index = key.offset;
3078         }
3079         btrfs_release_path(path);
3080 
3081         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3082         BUG_ON(ret);
3083 
3084         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3085         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3086         ret = btrfs_update_inode(trans, root, dir);
3087         BUG_ON(ret);
3088 
3089         btrfs_free_path(path);
3090         return 0;
3091 }
3092 
3093 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3094 {
3095         struct inode *inode = dentry->d_inode;
3096         int err = 0;
3097         struct btrfs_root *root = BTRFS_I(dir)->root;
3098         struct btrfs_trans_handle *trans;
3099         unsigned long nr = 0;
3100 
3101         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
3102             btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3103                 return -ENOTEMPTY;
3104 
3105         trans = __unlink_start_trans(dir, dentry);
3106         if (IS_ERR(trans))
3107                 return PTR_ERR(trans);
3108 
3109         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3110                 err = btrfs_unlink_subvol(trans, root, dir,
3111                                           BTRFS_I(inode)->location.objectid,
3112                                           dentry->d_name.name,
3113                                           dentry->d_name.len);
3114                 goto out;
3115         }
3116 
3117         err = btrfs_orphan_add(trans, inode);
3118         if (err)
3119                 goto out;
3120 
3121         /* now the directory is empty */
3122         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3123                                  dentry->d_name.name, dentry->d_name.len);
3124         if (!err)
3125                 btrfs_i_size_write(inode, 0);
3126 out:
3127         nr = trans->blocks_used;
3128         __unlink_end_trans(trans, root);
3129         btrfs_btree_balance_dirty(root, nr);
3130 
3131         return err;
3132 }
3133 
3134 /*
3135  * this can truncate away extent items, csum items and directory items.
3136  * It starts at a high offset and removes keys until it can't find
3137  * any higher than new_size
3138  *
3139  * csum items that cross the new i_size are truncated to the new size
3140  * as well.
3141  *
3142  * min_type is the minimum key type to truncate down to.  If set to 0, this
3143  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3144  */
3145 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3146                                struct btrfs_root *root,
3147                                struct inode *inode,
3148                                u64 new_size, u32 min_type)
3149 {
3150         struct btrfs_path *path;
3151         struct extent_buffer *leaf;
3152         struct btrfs_file_extent_item *fi;
3153         struct btrfs_key key;
3154         struct btrfs_key found_key;
3155         u64 extent_start = 0;
3156         u64 extent_num_bytes = 0;
3157         u64 extent_offset = 0;
3158         u64 item_end = 0;
3159         u64 mask = root->sectorsize - 1;
3160         u32 found_type = (u8)-1;
3161         int found_extent;
3162         int del_item;
3163         int pending_del_nr = 0;
3164         int pending_del_slot = 0;
3165         int extent_type = -1;
3166         int encoding;
3167         int ret;
3168         int err = 0;
3169         u64 ino = btrfs_ino(inode);
3170 
3171         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3172 
3173         if (root->ref_cows || root == root->fs_info->tree_root)
3174                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
3175 
3176         /*
3177          * This function is also used to drop the items in the log tree before
3178          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
3179          * it is used to drop the loged items. So we shouldn't kill the delayed
3180          * items.
3181          */
3182         if (min_type == 0 && root == BTRFS_I(inode)->root)
3183                 btrfs_kill_delayed_inode_items(inode);
3184 
3185         path = btrfs_alloc_path();
3186         BUG_ON(!path);
3187         path->reada = -1;
3188 
3189         key.objectid = ino;
3190         key.offset = (u64)-1;
3191         key.type = (u8)-1;
3192 
3193 search_again:
3194         path->leave_spinning = 1;
3195         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3196         if (ret < 0) {
3197                 err = ret;
3198                 goto out;
3199         }
3200 
3201         if (ret > 0) {
3202                 /* there are no items in the tree for us to truncate, we're
3203                  * done
3204                  */
3205                 if (path->slots[0] == 0)
3206                         goto out;
3207                 path->slots[0]--;
3208         }
3209 
3210         while (1) {
3211                 fi = NULL;
3212                 leaf = path->nodes[0];
3213                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3214                 found_type = btrfs_key_type(&found_key);
3215                 encoding = 0;
3216 
3217                 if (found_key.objectid != ino)
3218                         break;
3219 
3220                 if (found_type < min_type)
3221                         break;
3222 
3223                 item_end = found_key.offset;
3224                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
3225                         fi = btrfs_item_ptr(leaf, path->slots[0],
3226                                             struct btrfs_file_extent_item);
3227                         extent_type = btrfs_file_extent_type(leaf, fi);
3228                         encoding = btrfs_file_extent_compression(leaf, fi);
3229                         encoding |= btrfs_file_extent_encryption(leaf, fi);
3230                         encoding |= btrfs_file_extent_other_encoding(leaf, fi);
3231 
3232                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3233                                 item_end +=
3234                                     btrfs_file_extent_num_bytes(leaf, fi);
3235                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3236                                 item_end += btrfs_file_extent_inline_len(leaf,
3237                                                                          fi);
3238                         }
3239                         item_end--;
3240                 }
3241                 if (found_type > min_type) {
3242                         del_item = 1;
3243                 } else {
3244                         if (item_end < new_size)
3245                                 break;
3246                         if (found_key.offset >= new_size)
3247                                 del_item = 1;
3248                         else
3249                                 del_item = 0;
3250                 }
3251                 found_extent = 0;
3252                 /* FIXME, shrink the extent if the ref count is only 1 */
3253                 if (found_type != BTRFS_EXTENT_DATA_KEY)
3254                         goto delete;
3255 
3256                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3257                         u64 num_dec;
3258                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
3259                         if (!del_item && !encoding) {
3260                                 u64 orig_num_bytes =
3261                                         btrfs_file_extent_num_bytes(leaf, fi);
3262                                 extent_num_bytes = new_size -
3263                                         found_key.offset + root->sectorsize - 1;
3264                                 extent_num_bytes = extent_num_bytes &
3265                                         ~((u64)root->sectorsize - 1);
3266                                 btrfs_set_file_extent_num_bytes(leaf, fi,
3267                                                          extent_num_bytes);
3268                                 num_dec = (orig_num_bytes -
3269                                            extent_num_bytes);
3270                                 if (root->ref_cows && extent_start != 0)
3271                                         inode_sub_bytes(inode, num_dec);
3272                                 btrfs_mark_buffer_dirty(leaf);
3273                         } else {
3274                                 extent_num_bytes =
3275                                         btrfs_file_extent_disk_num_bytes(leaf,
3276                                                                          fi);
3277                                 extent_offset = found_key.offset -
3278                                         btrfs_file_extent_offset(leaf, fi);
3279 
3280                                 /* FIXME blocksize != 4096 */
3281                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
3282                                 if (extent_start != 0) {
3283                                         found_extent = 1;
3284                                         if (root->ref_cows)
3285                                                 inode_sub_bytes(inode, num_dec);
3286                                 }
3287                         }
3288                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3289                         /*
3290                          * we can't truncate inline items that have had
3291                          * special encodings
3292                          */
3293                         if (!del_item &&
3294                             btrfs_file_extent_compression(leaf, fi) == 0 &&
3295                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
3296                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
3297                                 u32 size = new_size - found_key.offset;
3298 
3299                                 if (root->ref_cows) {
3300                                         inode_sub_bytes(inode, item_end + 1 -
3301                                                         new_size);
3302                                 }
3303                                 size =
3304                                     btrfs_file_extent_calc_inline_size(size);
3305                                 ret = btrfs_truncate_item(trans, root, path,
3306                                                           size, 1);
3307                         } else if (root->ref_cows) {
3308                                 inode_sub_bytes(inode, item_end + 1 -
3309                                                 found_key.offset);
3310                         }
3311                 }
3312 delete:
3313                 if (del_item) {
3314                         if (!pending_del_nr) {
3315                                 /* no pending yet, add ourselves */
3316                                 pending_del_slot = path->slots[0];
3317                                 pending_del_nr = 1;
3318                         } else if (pending_del_nr &&
3319                                    path->slots[0] + 1 == pending_del_slot) {
3320                                 /* hop on the pending chunk */
3321                                 pending_del_nr++;
3322                                 pending_del_slot = path->slots[0];
3323                         } else {
3324                                 BUG();
3325                         }
3326                 } else {
3327                         break;
3328                 }
3329                 if (found_extent && (root->ref_cows ||
3330                                      root == root->fs_info->tree_root)) {
3331                         btrfs_set_path_blocking(path);
3332                         ret = btrfs_free_extent(trans, root, extent_start,
3333                                                 extent_num_bytes, 0,
3334                                                 btrfs_header_owner(leaf),
3335                                                 ino, extent_offset);
3336                         BUG_ON(ret);
3337                 }
3338 
3339                 if (found_type == BTRFS_INODE_ITEM_KEY)
3340                         break;
3341 
3342                 if (path->slots[0] == 0 ||
3343                     path->slots[0] != pending_del_slot) {
3344                         if (root->ref_cows &&
3345                             BTRFS_I(inode)->location.objectid !=
3346                                                 BTRFS_FREE_INO_OBJECTID) {
3347                                 err = -EAGAIN;
3348                                 goto out;
3349                         }
3350                         if (pending_del_nr) {
3351                                 ret = btrfs_del_items(trans, root, path,
3352                                                 pending_del_slot,
3353                                                 pending_del_nr);
3354                                 BUG_ON(ret);
3355                                 pending_del_nr = 0;
3356                         }
3357                         btrfs_release_path(path);
3358                         goto search_again;
3359                 } else {
3360                         path->slots[0]--;
3361                 }
3362         }
3363 out:
3364         if (pending_del_nr) {
3365                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
3366                                       pending_del_nr);
3367                 BUG_ON(ret);
3368         }
3369         btrfs_free_path(path);
3370         return err;
3371 }
3372 
3373 /*
3374  * taken from block_truncate_page, but does cow as it zeros out
3375  * any bytes left in the last page in the file.
3376  */
3377 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
3378 {
3379         struct inode *inode = mapping->host;
3380         struct btrfs_root *root = BTRFS_I(inode)->root;
3381         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3382         struct btrfs_ordered_extent *ordered;
3383         struct extent_state *cached_state = NULL;
3384         char *kaddr;
3385         u32 blocksize = root->sectorsize;
3386         pgoff_t index = from >> PAGE_CACHE_SHIFT;
3387         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3388         struct page *page;
3389         int ret = 0;
3390         u64 page_start;
3391         u64 page_end;
3392 
3393         if ((offset & (blocksize - 1)) == 0)
3394                 goto out;
3395         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
3396         if (ret)
3397                 goto out;
3398 
3399         ret = -ENOMEM;
3400 again:
3401         page = grab_cache_page(mapping, index);
3402         if (!page) {
3403                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3404                 goto out;
3405         }
3406 
3407         page_start = page_offset(page);
3408         page_end = page_start + PAGE_CACHE_SIZE - 1;
3409 
3410         if (!PageUptodate(page)) {
3411                 ret = btrfs_readpage(NULL, page);
3412                 lock_page(page);
3413                 if (page->mapping != mapping) {
3414                         unlock_page(page);
3415                         page_cache_release(page);
3416                         goto again;
3417                 }
3418                 if (!PageUptodate(page)) {
3419                         ret = -EIO;
3420                         goto out_unlock;
3421                 }
3422         }
3423         wait_on_page_writeback(page);
3424 
3425         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state,
3426                          GFP_NOFS);
3427         set_page_extent_mapped(page);
3428 
3429         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3430         if (ordered) {
3431                 unlock_extent_cached(io_tree, page_start, page_end,
3432                                      &cached_state, GFP_NOFS);
3433                 unlock_page(page);
3434                 page_cache_release(page);
3435                 btrfs_start_ordered_extent(inode, ordered, 1);
3436                 btrfs_put_ordered_extent(ordered);
3437                 goto again;
3438         }
3439 
3440         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
3441                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
3442                           0, 0, &cached_state, GFP_NOFS);
3443 
3444         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
3445                                         &cached_state);
3446         if (ret) {
3447                 unlock_extent_cached(io_tree, page_start, page_end,
3448                                      &cached_state, GFP_NOFS);
3449                 goto out_unlock;
3450         }
3451 
3452         ret = 0;
3453         if (offset != PAGE_CACHE_SIZE) {
3454                 kaddr = kmap(page);
3455                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3456                 flush_dcache_page(page);
3457                 kunmap(page);
3458         }
3459         ClearPageChecked(page);
3460         set_page_dirty(page);
3461         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
3462                              GFP_NOFS);
3463 
3464 out_unlock:
3465         if (ret)
3466                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3467         unlock_page(page);
3468         page_cache_release(page);
3469 out:
3470         return ret;
3471 }
3472 
3473 /*
3474  * This function puts in dummy file extents for the area we're creating a hole
3475  * for.  So if we are truncating this file to a larger size we need to insert
3476  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
3477  * the range between oldsize and size
3478  */
3479 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
3480 {
3481         struct btrfs_trans_handle *trans;
3482         struct btrfs_root *root = BTRFS_I(inode)->root;
3483         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3484         struct extent_map *em = NULL;
3485         struct extent_state *cached_state = NULL;
3486         u64 mask = root->sectorsize - 1;
3487         u64 hole_start = (oldsize + mask) & ~mask;
3488         u64 block_end = (size + mask) & ~mask;
3489         u64 last_byte;
3490         u64 cur_offset;
3491         u64 hole_size;
3492         int err = 0;
3493 
3494         if (size <= hole_start)
3495                 return 0;
3496 
3497         while (1) {
3498                 struct btrfs_ordered_extent *ordered;
3499                 btrfs_wait_ordered_range(inode, hole_start,
3500                                          block_end - hole_start);
3501                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
3502                                  &cached_state, GFP_NOFS);
3503                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3504                 if (!ordered)
3505                         break;
3506                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
3507                                      &cached_state, GFP_NOFS);
3508                 btrfs_put_ordered_extent(ordered);
3509         }
3510 
3511         cur_offset = hole_start;
3512         while (1) {
3513                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3514                                 block_end - cur_offset, 0);
3515                 BUG_ON(IS_ERR_OR_NULL(em));
3516                 last_byte = min(extent_map_end(em), block_end);
3517                 last_byte = (last_byte + mask) & ~mask;
3518                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3519                         u64 hint_byte = 0;
3520                         hole_size = last_byte - cur_offset;
3521 
3522                         trans = btrfs_start_transaction(root, 2);
3523                         if (IS_ERR(trans)) {
3524                                 err = PTR_ERR(trans);
3525                                 break;
3526                         }
3527 
3528                         err = btrfs_drop_extents(trans, inode, cur_offset,
3529                                                  cur_offset + hole_size,
3530                                                  &hint_byte, 1);
3531                         if (err)
3532                                 break;
3533 
3534                         err = btrfs_insert_file_extent(trans, root,
3535                                         btrfs_ino(inode), cur_offset, 0,
3536                                         0, hole_size, 0, hole_size,
3537                                         0, 0, 0);
3538                         if (err)
3539                                 break;
3540 
3541                         btrfs_drop_extent_cache(inode, hole_start,
3542                                         last_byte - 1, 0);
3543 
3544                         btrfs_end_transaction(trans, root);
3545                 }
3546                 free_extent_map(em);
3547                 em = NULL;
3548                 cur_offset = last_byte;
3549                 if (cur_offset >= block_end)
3550                         break;
3551         }
3552 
3553         free_extent_map(em);
3554         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
3555                              GFP_NOFS);
3556         return err;
3557 }
3558 
3559 static int btrfs_setsize(struct inode *inode, loff_t newsize)
3560 {
3561         loff_t oldsize = i_size_read(inode);
3562         int ret;
3563 
3564         if (newsize == oldsize)
3565                 return 0;
3566 
3567         if (newsize > oldsize) {
3568                 i_size_write(inode, newsize);
3569                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
3570                 truncate_pagecache(inode, oldsize, newsize);
3571                 ret = btrfs_cont_expand(inode, oldsize, newsize);
3572                 if (ret) {
3573                         btrfs_setsize(inode, oldsize);
3574                         return ret;
3575                 }
3576 
3577                 mark_inode_dirty(inode);
3578         } else {
3579 
3580                 /*
3581                  * We're truncating a file that used to have good data down to
3582                  * zero. Make sure it gets into the ordered flush list so that
3583                  * any new writes get down to disk quickly.
3584                  */
3585                 if (newsize == 0)
3586                         BTRFS_I(inode)->ordered_data_close = 1;
3587 
3588                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
3589                 truncate_setsize(inode, newsize);
3590                 ret = btrfs_truncate(inode);
3591         }
3592 
3593         return ret;
3594 }
3595 
3596 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3597 {
3598         struct inode *inode = dentry->d_inode;
3599         struct btrfs_root *root = BTRFS_I(inode)->root;
3600         int err;
3601 
3602         if (btrfs_root_readonly(root))
3603                 return -EROFS;
3604 
3605         err = inode_change_ok(inode, attr);
3606         if (err)
3607                 return err;
3608 
3609         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3610                 err = btrfs_setsize(inode, attr->ia_size);
3611                 if (err)
3612                         return err;
3613         }
3614 
3615         if (attr->ia_valid) {
3616                 setattr_copy(inode, attr);
3617                 mark_inode_dirty(inode);
3618 
3619                 if (attr->ia_valid & ATTR_MODE)
3620                         err = btrfs_acl_chmod(inode);
3621         }
3622 
3623         return err;
3624 }
3625 
3626 void btrfs_evict_inode(struct inode *inode)
3627 {
3628         struct btrfs_trans_handle *trans;
3629         struct btrfs_root *root = BTRFS_I(inode)->root;
3630         unsigned long nr;
3631         int ret;
3632 
3633         trace_btrfs_inode_evict(inode);
3634 
3635         truncate_inode_pages(&inode->i_data, 0);
3636         if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
3637                                is_free_space_inode(root, inode)))
3638                 goto no_delete;
3639 
3640         if (is_bad_inode(inode)) {
3641                 btrfs_orphan_del(NULL, inode);
3642                 goto no_delete;
3643         }
3644         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
3645         btrfs_wait_ordered_range(inode, 0, (u64)-1);
3646 
3647         if (root->fs_info->log_root_recovering) {
3648                 BUG_ON(!list_empty(&BTRFS_I(inode)->i_orphan));
3649                 goto no_delete;
3650         }
3651 
3652         if (inode->i_nlink > 0) {
3653                 BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3654                 goto no_delete;
3655         }
3656 
3657         btrfs_i_size_write(inode, 0);
3658 
3659         while (1) {
3660                 trans = btrfs_join_transaction(root);
3661                 BUG_ON(IS_ERR(trans));
3662                 trans->block_rsv = root->orphan_block_rsv;
3663 
3664                 ret = btrfs_block_rsv_check(trans, root,
3665                                             root->orphan_block_rsv, 0, 5);
3666                 if (ret) {
3667                         BUG_ON(ret != -EAGAIN);
3668                         ret = btrfs_commit_transaction(trans, root);
3669                         BUG_ON(ret);
3670                         continue;
3671                 }
3672 
3673                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
3674                 if (ret != -EAGAIN)
3675                         break;
3676 
3677                 nr = trans->blocks_used;
3678                 btrfs_end_transaction(trans, root);
3679                 trans = NULL;
3680                 btrfs_btree_balance_dirty(root, nr);
3681 
3682         }
3683 
3684         if (ret == 0) {
3685                 ret = btrfs_orphan_del(trans, inode);
3686                 BUG_ON(ret);
3687         }
3688 
3689         if (!(root == root->fs_info->tree_root ||
3690               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
3691                 btrfs_return_ino(root, btrfs_ino(inode));
3692 
3693         nr = trans->blocks_used;
3694         btrfs_end_transaction(trans, root);
3695         btrfs_btree_balance_dirty(root, nr);
3696 no_delete:
3697         end_writeback(inode);
3698         return;
3699 }
3700 
3701 /*
3702  * this returns the key found in the dir entry in the location pointer.
3703  * If no dir entries were found, location->objectid is 0.
3704  */
3705 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3706                                struct btrfs_key *location)
3707 {
3708         const char *name = dentry->d_name.name;
3709         int namelen = dentry->d_name.len;
3710         struct btrfs_dir_item *di;
3711         struct btrfs_path *path;
3712         struct btrfs_root *root = BTRFS_I(dir)->root;
3713         int ret = 0;
3714 
3715         path = btrfs_alloc_path();
3716         BUG_ON(!path);
3717 
3718         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
3719                                     namelen, 0);
3720         if (IS_ERR(di))
3721                 ret = PTR_ERR(di);
3722 
3723         if (IS_ERR_OR_NULL(di))
3724                 goto out_err;
3725 
3726         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3727 out:
3728         btrfs_free_path(path);
3729         return ret;
3730 out_err:
3731         location->objectid = 0;
3732         goto out;
3733 }
3734 
3735 /*
3736  * when we hit a tree root in a directory, the btrfs part of the inode
3737  * needs to be changed to reflect the root directory of the tree root.  This
3738  * is kind of like crossing a mount point.
3739  */
3740 static int fixup_tree_root_location(struct btrfs_root *root,
3741                                     struct inode *dir,
3742                                     struct dentry *dentry,
3743                                     struct btrfs_key *location,
3744                                     struct btrfs_root **sub_root)
3745 {
3746         struct btrfs_path *path;
3747         struct btrfs_root *new_root;
3748         struct btrfs_root_ref *ref;
3749         struct extent_buffer *leaf;
3750         int ret;
3751         int err = 0;
3752 
3753         path = btrfs_alloc_path();
3754         if (!path) {
3755                 err = -ENOMEM;
3756                 goto out;
3757         }
3758 
3759         err = -ENOENT;
3760         ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3761                                   BTRFS_I(dir)->root->root_key.objectid,
3762                                   location->objectid);
3763         if (ret) {
3764                 if (ret < 0)
3765                         err = ret;
3766                 goto out;
3767         }
3768 
3769         leaf = path->nodes[0];
3770         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3771         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
3772             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3773                 goto out;
3774 
3775         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3776                                    (unsigned long)(ref + 1),
3777                                    dentry->d_name.len);
3778         if (ret)
3779                 goto out;
3780 
3781         btrfs_release_path(path);
3782 
3783         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3784         if (IS_ERR(new_root)) {
3785                 err = PTR_ERR(new_root);
3786                 goto out;
3787         }
3788 
3789         if (btrfs_root_refs(&new_root->root_item) == 0) {
3790                 err = -ENOENT;
3791                 goto out;
3792         }
3793 
3794         *sub_root = new_root;
3795         location->objectid = btrfs_root_dirid(&new_root->root_item);
3796         location->type = BTRFS_INODE_ITEM_KEY;
3797         location->offset = 0;
3798         err = 0;
3799 out:
3800         btrfs_free_path(path);
3801         return err;
3802 }
3803 
3804 static void inode_tree_add(struct inode *inode)
3805 {
3806         struct btrfs_root *root = BTRFS_I(inode)->root;
3807         struct btrfs_inode *entry;
3808         struct rb_node **p;
3809         struct rb_node *parent;
3810         u64 ino = btrfs_ino(inode);
3811 again:
3812         p = &root->inode_tree.rb_node;
3813         parent = NULL;
3814 
3815         if (inode_unhashed(inode))
3816                 return;
3817 
3818         spin_lock(&root->inode_lock);
3819         while (*p) {
3820                 parent = *p;
3821                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
3822 
3823                 if (ino < btrfs_ino(&entry->vfs_inode))
3824                         p = &parent->rb_left;
3825                 else if (ino > btrfs_ino(&entry->vfs_inode))
3826                         p = &parent->rb_right;
3827                 else {
3828                         WARN_ON(!(entry->vfs_inode.i_state &
3829                                   (I_WILL_FREE | I_FREEING)));
3830                         rb_erase(parent, &root->inode_tree);
3831                         RB_CLEAR_NODE(parent);
3832                         spin_unlock(&root->inode_lock);
3833                         goto again;
3834                 }
3835         }
3836         rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
3837         rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3838         spin_unlock(&root->inode_lock);
3839 }
3840 
3841 static void inode_tree_del(struct inode *inode)
3842 {
3843         struct btrfs_root *root = BTRFS_I(inode)->root;
3844         int empty = 0;
3845 
3846         spin_lock(&root->inode_lock);
3847         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
3848                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3849                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3850                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3851         }
3852         spin_unlock(&root->inode_lock);
3853 
3854         /*
3855          * Free space cache has inodes in the tree root, but the tree root has a
3856          * root_refs of 0, so this could end up dropping the tree root as a
3857          * snapshot, so we need the extra !root->fs_info->tree_root check to
3858          * make sure we don't drop it.
3859          */
3860         if (empty && btrfs_root_refs(&root->root_item) == 0 &&
3861             root != root->fs_info->tree_root) {
3862                 synchronize_srcu(&root->fs_info->subvol_srcu);
3863                 spin_lock(&root->inode_lock);
3864                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3865                 spin_unlock(&root->inode_lock);
3866                 if (empty)
3867                         btrfs_add_dead_root(root);
3868         }
3869 }
3870 
3871 int btrfs_invalidate_inodes(struct btrfs_root *root)
3872 {
3873         struct rb_node *node;
3874         struct rb_node *prev;
3875         struct btrfs_inode *entry;
3876         struct inode *inode;
3877         u64 objectid = 0;
3878 
3879         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
3880 
3881         spin_lock(&root->inode_lock);
3882 again:
3883         node = root->inode_tree.rb_node;
3884         prev = NULL;
3885         while (node) {
3886                 prev = node;
3887                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3888 
3889                 if (objectid < btrfs_ino(&entry->vfs_inode))
3890                         node = node->rb_left;
3891                 else if (objectid > btrfs_ino(&entry->vfs_inode))
3892                         node = node->rb_right;
3893                 else
3894                         break;
3895         }
3896         if (!node) {
3897                 while (prev) {
3898                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
3899                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
3900                                 node = prev;
3901                                 break;
3902                         }
3903                         prev = rb_next(prev);
3904                 }
3905         }
3906         while (node) {
3907                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3908                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
3909                 inode = igrab(&entry->vfs_inode);
3910                 if (inode) {
3911                         spin_unlock(&root->inode_lock);
3912                         if (atomic_read(&inode->i_count) > 1)
3913                                 d_prune_aliases(inode);
3914                         /*
3915                          * btrfs_drop_inode will have it removed from
3916                          * the inode cache when its usage count
3917                          * hits zero.
3918                          */
3919                         iput(inode);
3920                         cond_resched();
3921                         spin_lock(&root->inode_lock);
3922                         goto again;
3923                 }
3924 
3925                 if (cond_resched_lock(&root->inode_lock))
3926                         goto again;
3927 
3928                 node = rb_next(node);
3929         }
3930         spin_unlock(&root->inode_lock);
3931         return 0;
3932 }
3933 
3934 static int btrfs_init_locked_inode(struct inode *inode, void *p)
3935 {
3936         struct btrfs_iget_args *args = p;
3937         inode->i_ino = args->ino;
3938         BTRFS_I(inode)->root = args->root;
3939         btrfs_set_inode_space_info(args->root, inode);
3940         return 0;
3941 }
3942 
3943 static int btrfs_find_actor(struct inode *inode, void *opaque)
3944 {
3945         struct btrfs_iget_args *args = opaque;
3946         return args->ino == btrfs_ino(inode) &&
3947                 args->root == BTRFS_I(inode)->root;
3948 }
3949 
3950 static struct inode *btrfs_iget_locked(struct super_block *s,
3951                                        u64 objectid,
3952                                        struct btrfs_root *root)
3953 {
3954         struct inode *inode;
3955         struct btrfs_iget_args args;
3956         args.ino = objectid;
3957         args.root = root;
3958 
3959         inode = iget5_locked(s, objectid, btrfs_find_actor,
3960                              btrfs_init_locked_inode,
3961                              (void *)&args);
3962         return inode;
3963 }
3964 
3965 /* Get an inode object given its location and corresponding root.
3966  * Returns in *is_new if the inode was read from disk
3967  */
3968 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
3969                          struct btrfs_root *root, int *new)
3970 {
3971         struct inode *inode;
3972 
3973         inode = btrfs_iget_locked(s, location->objectid, root);
3974         if (!inode)
3975                 return ERR_PTR(-ENOMEM);
3976 
3977         if (inode->i_state & I_NEW) {
3978                 BTRFS_I(inode)->root = root;
3979                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
3980                 btrfs_read_locked_inode(inode);
3981                 inode_tree_add(inode);
3982                 unlock_new_inode(inode);
3983                 if (new)
3984                         *new = 1;
3985         }
3986 
3987         return inode;
3988 }
3989 
3990 static struct inode *new_simple_dir(struct super_block *s,
3991                                     struct btrfs_key *key,
3992                                     struct btrfs_root *root)
3993 {
3994         struct inode *inode = new_inode(s);
3995 
3996         if (!inode)
3997                 return ERR_PTR(-ENOMEM);
3998 
3999         BTRFS_I(inode)->root = root;
4000         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
4001         BTRFS_I(inode)->dummy_inode = 1;
4002 
4003         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
4004         inode->i_op = &simple_dir_inode_operations;
4005         inode->i_fop = &simple_dir_operations;
4006         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
4007         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4008 
4009         return inode;
4010 }
4011 
4012 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
4013 {
4014         struct inode *inode;
4015         struct btrfs_root *root = BTRFS_I(dir)->root;
4016         struct btrfs_root *sub_root = root;
4017         struct btrfs_key location;
4018         int index;
4019         int ret;
4020 
4021         if (dentry->d_name.len > BTRFS_NAME_LEN)
4022                 return ERR_PTR(-ENAMETOOLONG);
4023 
4024         ret = btrfs_inode_by_name(dir, dentry, &location);
4025 
4026         if (ret < 0)
4027                 return ERR_PTR(ret);
4028 
4029         if (location.objectid == 0)
4030                 return NULL;
4031 
4032         if (location.type == BTRFS_INODE_ITEM_KEY) {
4033                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
4034                 return inode;
4035         }
4036 
4037         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
4038 
4039         index = srcu_read_lock(&root->fs_info->subvol_srcu);
4040         ret = fixup_tree_root_location(root, dir, dentry,
4041                                        &location, &sub_root);
4042         if (ret < 0) {
4043                 if (ret != -ENOENT)
4044                         inode = ERR_PTR(ret);
4045                 else
4046                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
4047         } else {
4048                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
4049         }
4050         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
4051 
4052         if (!IS_ERR(inode) && root != sub_root) {
4053                 down_read(&root->fs_info->cleanup_work_sem);
4054                 if (!(inode->i_sb->s_flags & MS_RDONLY))
4055                         ret = btrfs_orphan_cleanup(sub_root);
4056                 up_read(&root->fs_info->cleanup_work_sem);
4057                 if (ret)
4058                         inode = ERR_PTR(ret);
4059         }
4060 
4061         return inode;
4062 }
4063 
4064 static int btrfs_dentry_delete(const struct dentry *dentry)
4065 {
4066         struct btrfs_root *root;
4067 
4068         if (!dentry->d_inode && !IS_ROOT(dentry))
4069                 dentry = dentry->d_parent;
4070 
4071         if (dentry->d_inode) {
4072                 root = BTRFS_I(dentry->d_inode)->root;
4073                 if (btrfs_root_refs(&root->root_item) == 0)
4074                         return 1;
4075         }
4076         return 0;
4077 }
4078 
4079 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
4080                                    struct nameidata *nd)
4081 {
4082         struct inode *inode;
4083 
4084         inode = btrfs_lookup_dentry(dir, dentry);
4085         if (IS_ERR(inode))
4086                 return ERR_CAST(inode);
4087 
4088         return d_splice_alias(inode, dentry);
4089 }
4090 
4091 unsigned char btrfs_filetype_table[] = {
4092         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
4093 };
4094 
4095 static int btrfs_real_readdir(struct file *filp, void *dirent,
4096                               filldir_t filldir)
4097 {
4098         struct inode *inode = filp->f_dentry->d_inode;
4099         struct btrfs_root *root = BTRFS_I(inode)->root;
4100         struct btrfs_item *item;
4101         struct btrfs_dir_item *di;
4102         struct btrfs_key key;
4103         struct btrfs_key found_key;
4104         struct btrfs_path *path;
4105         struct list_head ins_list;
4106         struct list_head del_list;
4107         int ret;
4108         struct extent_buffer *leaf;
4109         int slot;
4110         unsigned char d_type;
4111         int over = 0;
4112         u32 di_cur;
4113         u32 di_total;
4114         u32 di_len;
4115         int key_type = BTRFS_DIR_INDEX_KEY;
4116         char tmp_name[32];
4117         char *name_ptr;
4118         int name_len;
4119         int is_curr = 0;        /* filp->f_pos points to the current index? */
4120 
4121         /* FIXME, use a real flag for deciding about the key type */
4122         if (root->fs_info->tree_root == root)
4123                 key_type = BTRFS_DIR_ITEM_KEY;
4124 
4125         /* special case for "." */
4126         if (filp->f_pos == 0) {
4127                 over = filldir(dirent, ".", 1,
4128                                filp->f_pos, btrfs_ino(inode), DT_DIR);
4129                 if (over)
4130                         return 0;
4131                 filp->f_pos = 1;
4132         }
4133         /* special case for .., just use the back ref */
4134         if (filp->f_pos == 1) {
4135                 u64 pino = parent_ino(filp->f_path.dentry);
4136                 over = filldir(dirent, "..", 2,
4137                                filp->f_pos, pino, DT_DIR);
4138                 if (over)
4139                         return 0;
4140                 filp->f_pos = 2;
4141         }
4142         path = btrfs_alloc_path();
4143         if (!path)
4144                 return -ENOMEM;
4145 
4146         path->reada = 1;
4147 
4148         if (key_type == BTRFS_DIR_INDEX_KEY) {
4149                 INIT_LIST_HEAD(&ins_list);
4150                 INIT_LIST_HEAD(&del_list);
4151                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
4152         }
4153 
4154         btrfs_set_key_type(&key, key_type);
4155         key.offset = filp->f_pos;
4156         key.objectid = btrfs_ino(inode);
4157 
4158         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4159         if (ret < 0)
4160                 goto err;
4161 
4162         while (1) {
4163                 leaf = path->nodes[0];
4164                 slot = path->slots[0];
4165                 if (slot >= btrfs_header_nritems(leaf)) {
4166                         ret = btrfs_next_leaf(root, path);
4167                         if (ret < 0)
4168                                 goto err;
4169                         else if (ret > 0)
4170                                 break;
4171                         continue;
4172                 }
4173 
4174                 item = btrfs_item_nr(leaf, slot);
4175                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4176 
4177                 if (found_key.objectid != key.objectid)
4178                         break;
4179                 if (btrfs_key_type(&found_key) != key_type)
4180                         break;
4181                 if (found_key.offset < filp->f_pos)
4182                         goto next;
4183                 if (key_type == BTRFS_DIR_INDEX_KEY &&
4184                     btrfs_should_delete_dir_index(&del_list,
4185                                                   found_key.offset))
4186                         goto next;
4187 
4188                 filp->f_pos = found_key.offset;
4189                 is_curr = 1;
4190 
4191                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
4192                 di_cur = 0;
4193                 di_total = btrfs_item_size(leaf, item);
4194 
4195                 while (di_cur < di_total) {
4196                         struct btrfs_key location;
4197 
4198                         if (verify_dir_item(root, leaf, di))
4199                                 break;
4200 
4201                         name_len = btrfs_dir_name_len(leaf, di);
4202                         if (name_len <= sizeof(tmp_name)) {
4203                                 name_ptr = tmp_name;
4204                         } else {
4205                                 name_ptr = kmalloc(name_len, GFP_NOFS);
4206                                 if (!name_ptr) {
4207                                         ret = -ENOMEM;
4208                                         goto err;
4209                                 }
4210                         }
4211                         read_extent_buffer(leaf, name_ptr,
4212                                            (unsigned long)(di + 1), name_len);
4213 
4214                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
4215                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
4216 
4217                         /* is this a reference to our own snapshot? If so
4218                          * skip it
4219                          */
4220                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
4221                             location.objectid == root->root_key.objectid) {
4222                                 over = 0;
4223                                 goto skip;
4224                         }
4225                         over = filldir(dirent, name_ptr, name_len,
4226                                        found_key.offset, location.objectid,
4227                                        d_type);
4228 
4229 skip:
4230                         if (name_ptr != tmp_name)
4231                                 kfree(name_ptr);
4232 
4233                         if (over)
4234                                 goto nopos;
4235                         di_len = btrfs_dir_name_len(leaf, di) +
4236                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
4237                         di_cur += di_len;
4238                         di = (struct btrfs_dir_item *)((char *)di + di_len);
4239                 }
4240 next:
4241                 path->slots[0]++;
4242         }
4243 
4244         if (key_type == BTRFS_DIR_INDEX_KEY) {
4245                 if (is_curr)
4246                         filp->f_pos++;
4247                 ret = btrfs_readdir_delayed_dir_index(filp, dirent, filldir,
4248                                                       &ins_list);
4249                 if (ret)
4250                         goto nopos;
4251         }
4252 
4253         /* Reached end of directory/root. Bump pos past the last item. */
4254         if (key_type == BTRFS_DIR_INDEX_KEY)
4255                 /*
4256                  * 32-bit glibc will use getdents64, but then strtol -
4257                  * so the last number we can serve is this.
4258                  */
4259                 filp->f_pos = 0x7fffffff;
4260         else
4261                 filp->f_pos++;
4262 nopos:
4263         ret = 0;
4264 err:
4265         if (key_type == BTRFS_DIR_INDEX_KEY)
4266                 btrfs_put_delayed_items(&ins_list, &del_list);
4267         btrfs_free_path(path);
4268         return ret;
4269 }
4270 
4271 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
4272 {
4273         struct btrfs_root *root = BTRFS_I(inode)->root;
4274         struct btrfs_trans_handle *trans;
4275         int ret = 0;
4276         bool nolock = false;
4277 
4278         if (BTRFS_I(inode)->dummy_inode)
4279                 return 0;
4280 
4281         if (btrfs_fs_closing(root->fs_info) && is_free_space_inode(root, inode))
4282                 nolock = true;
4283 
4284         if (wbc->sync_mode == WB_SYNC_ALL) {
4285                 if (nolock)
4286                         trans = btrfs_join_transaction_nolock(root);
4287                 else
4288                         trans = btrfs_join_transaction(root);
4289                 if (IS_ERR(trans))
4290                         return PTR_ERR(trans);
4291                 if (nolock)
4292                         ret = btrfs_end_transaction_nolock(trans, root);
4293                 else
4294                         ret = btrfs_commit_transaction(trans, root);
4295         }
4296         return ret;
4297 }
4298 
4299 /*
4300  * This is somewhat expensive, updating the tree every time the
4301  * inode changes.  But, it is most likely to find the inode in cache.
4302  * FIXME, needs more benchmarking...there are no reasons other than performance
4303  * to keep or drop this code.
4304  */
4305 void btrfs_dirty_inode(struct inode *inode, int flags)
4306 {
4307         struct btrfs_root *root = BTRFS_I(inode)->root;
4308         struct btrfs_trans_handle *trans;
4309         int ret;
4310 
4311         if (BTRFS_I(inode)->dummy_inode)
4312                 return;
4313 
4314         trans = btrfs_join_transaction(root);
4315         BUG_ON(IS_ERR(trans));
4316 
4317         ret = btrfs_update_inode(trans, root, inode);
4318         if (ret && ret == -ENOSPC) {
4319                 /* whoops, lets try again with the full transaction */
4320                 btrfs_end_transaction(trans, root);
4321                 trans = btrfs_start_transaction(root, 1);
4322                 if (IS_ERR(trans)) {
4323                         printk_ratelimited(KERN_ERR "btrfs: fail to "
4324                                        "dirty  inode %llu error %ld\n",
4325                                        (unsigned long long)btrfs_ino(inode),
4326                                        PTR_ERR(trans));
4327                         return;
4328                 }
4329 
4330                 ret = btrfs_update_inode(trans, root, inode);
4331                 if (ret) {
4332                         printk_ratelimited(KERN_ERR "btrfs: fail to "
4333                                        "dirty  inode %llu error %d\n",
4334                                        (unsigned long long)btrfs_ino(inode),
4335                                        ret);
4336                 }
4337         }
4338         btrfs_end_transaction(trans, root);
4339         if (BTRFS_I(inode)->delayed_node)
4340                 btrfs_balance_delayed_items(root);
4341 }
4342 
4343 /*
4344  * find the highest existing sequence number in a directory
4345  * and then set the in-memory index_cnt variable to reflect
4346  * free sequence numbers
4347  */
4348 static int btrfs_set_inode_index_count(struct inode *inode)
4349 {
4350         struct btrfs_root *root = BTRFS_I(inode)->root;
4351         struct btrfs_key key, found_key;
4352         struct btrfs_path *path;
4353         struct extent_buffer *leaf;
4354         int ret;
4355 
4356         key.objectid = btrfs_ino(inode);
4357         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
4358         key.offset = (u64)-1;
4359 
4360         path = btrfs_alloc_path();
4361         if (!path)
4362                 return -ENOMEM;
4363 
4364         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4365         if (ret < 0)
4366                 goto out;
4367         /* FIXME: we should be able to handle this */
4368         if (ret == 0)
4369                 goto out;
4370         ret = 0;
4371 
4372         /*
4373          * MAGIC NUMBER EXPLANATION:
4374          * since we search a directory based on f_pos we have to start at 2
4375          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
4376          * else has to start at 2
4377          */
4378         if (path->slots[0] == 0) {
4379                 BTRFS_I(inode)->index_cnt = 2;
4380                 goto out;
4381         }
4382 
4383         path->slots[0]--;
4384 
4385         leaf = path->nodes[0];
4386         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4387 
4388         if (found_key.objectid != btrfs_ino(inode) ||
4389             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
4390                 BTRFS_I(inode)->index_cnt = 2;
4391                 goto out;
4392         }
4393 
4394         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
4395 out:
4396         btrfs_free_path(path);
4397         return ret;
4398 }
4399 
4400 /*
4401  * helper to find a free sequence number in a given directory.  This current
4402  * code is very simple, later versions will do smarter things in the btree
4403  */
4404 int btrfs_set_inode_index(struct inode *dir, u64 *index)
4405 {
4406         int ret = 0;
4407 
4408         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
4409                 ret = btrfs_inode_delayed_dir_index_count(dir);
4410                 if (ret) {
4411                         ret = btrfs_set_inode_index_count(dir);
4412                         if (ret)
4413                                 return ret;
4414                 }
4415         }
4416 
4417         *index = BTRFS_I(dir)->index_cnt;
4418         BTRFS_I(dir)->index_cnt++;
4419 
4420         return ret;
4421 }
4422 
4423 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
4424                                      struct btrfs_root *root,
4425                                      struct inode *dir,
4426                                      const char *name, int name_len,
4427                                      u64 ref_objectid, u64 objectid, int mode,
4428                                      u64 *index)
4429 {
4430         struct inode *inode;
4431         struct btrfs_inode_item *inode_item;
4432         struct btrfs_key *location;
4433         struct btrfs_path *path;
4434         struct btrfs_inode_ref *ref;
4435         struct btrfs_key key[2];
4436         u32 sizes[2];
4437         unsigned long ptr;
4438         int ret;
4439         int owner;
4440 
4441         path = btrfs_alloc_path();
4442         BUG_ON(!path);
4443 
4444         inode = new_inode(root->fs_info->sb);
4445         if (!inode) {
4446                 btrfs_free_path(path);
4447                 return ERR_PTR(-ENOMEM);
4448         }
4449 
4450         /*
4451          * we have to initialize this early, so we can reclaim the inode
4452          * number if we fail afterwards in this function.
4453          */
4454         inode->i_ino = objectid;
4455 
4456         if (dir) {
4457                 trace_btrfs_inode_request(dir);
4458 
4459                 ret = btrfs_set_inode_index(dir, index);
4460                 if (ret) {
4461                         btrfs_free_path(path);
4462                         iput(inode);
4463                         return ERR_PTR(ret);
4464                 }
4465         }
4466         /*
4467          * index_cnt is ignored for everything but a dir,
4468          * btrfs_get_inode_index_count has an explanation for the magic
4469          * number
4470          */
4471         BTRFS_I(inode)->index_cnt = 2;
4472         BTRFS_I(inode)->root = root;
4473         BTRFS_I(inode)->generation = trans->transid;
4474         inode->i_generation = BTRFS_I(inode)->generation;
4475         btrfs_set_inode_space_info(root, inode);
4476 
4477         if (mode & S_IFDIR)
4478                 owner = 0;
4479         else
4480                 owner = 1;
4481 
4482         key[0].objectid = objectid;
4483         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
4484         key[0].offset = 0;
4485 
4486         key[1].objectid = objectid;
4487         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
4488         key[1].offset = ref_objectid;
4489 
4490         sizes[0] = sizeof(struct btrfs_inode_item);
4491         sizes[1] = name_len + sizeof(*ref);
4492 
4493         path->leave_spinning = 1;
4494         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
4495         if (ret != 0)
4496                 goto fail;
4497 
4498         inode_init_owner(inode, dir, mode);
4499         inode_set_bytes(inode, 0);
4500         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4501         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
4502                                   struct btrfs_inode_item);
4503         fill_inode_item(trans, path->nodes[0], inode_item, inode);
4504 
4505         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
4506                              struct btrfs_inode_ref);
4507         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
4508         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
4509         ptr = (unsigned long)(ref + 1);
4510         write_extent_buffer(path->nodes[0], name, ptr, name_len);
4511 
4512         btrfs_mark_buffer_dirty(path->nodes[0]);
4513         btrfs_free_path(path);
4514 
4515         location = &BTRFS_I(inode)->location;
4516         location->objectid = objectid;
4517         location->offset = 0;
4518         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
4519 
4520         btrfs_inherit_iflags(inode, dir);
4521 
4522         if ((mode & S_IFREG)) {
4523                 if (btrfs_test_opt(root, NODATASUM))
4524                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
4525                 if (btrfs_test_opt(root, NODATACOW) ||
4526                     (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
4527                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
4528         }
4529 
4530         insert_inode_hash(inode);
4531         inode_tree_add(inode);
4532 
4533         trace_btrfs_inode_new(inode);
4534         btrfs_set_inode_last_trans(trans, inode);
4535 
4536         return inode;
4537 fail:
4538         if (dir)
4539                 BTRFS_I(dir)->index_cnt--;
4540         btrfs_free_path(path);
4541         iput(inode);
4542         return ERR_PTR(ret);
4543 }
4544 
4545 static inline u8 btrfs_inode_type(struct inode *inode)
4546 {
4547         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4548 }
4549 
4550 /*
4551  * utility function to add 'inode' into 'parent_inode' with
4552  * a give name and a given sequence number.
4553  * if 'add_backref' is true, also insert a backref from the
4554  * inode to the parent directory.
4555  */
4556 int btrfs_add_link(struct btrfs_trans_handle *trans,
4557                    struct inode *parent_inode, struct inode *inode,
4558                    const char *name, int name_len, int add_backref, u64 index)
4559 {
4560         int ret = 0;
4561         struct btrfs_key key;
4562         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4563         u64 ino = btrfs_ino(inode);
4564         u64 parent_ino = btrfs_ino(parent_inode);
4565 
4566         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4567                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4568         } else {
4569                 key.objectid = ino;
4570                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4571                 key.offset = 0;
4572         }
4573 
4574         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4575                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4576                                          key.objectid, root->root_key.objectid,
4577                                          parent_ino, index, name, name_len);
4578         } else if (add_backref) {
4579                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
4580                                              parent_ino, index);
4581         }
4582 
4583         if (ret == 0) {
4584                 ret = btrfs_insert_dir_item(trans, root, name, name_len,
4585                                             parent_inode, &key,
4586                                             btrfs_inode_type(inode), index);
4587                 BUG_ON(ret);
4588 
4589                 btrfs_i_size_write(parent_inode, parent_inode->i_size +
4590                                    name_len * 2);
4591                 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4592                 ret = btrfs_update_inode(trans, root, parent_inode);
4593         }
4594         return ret;
4595 }
4596 
4597 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4598                             struct inode *dir, struct dentry *dentry,
4599                             struct inode *inode, int backref, u64 index)
4600 {
4601         int err = btrfs_add_link(trans, dir, inode,
4602                                  dentry->d_name.name, dentry->d_name.len,
4603                                  backref, index);
4604         if (!err) {
4605                 d_instantiate(dentry, inode);
4606                 return 0;
4607         }
4608         if (err > 0)
4609                 err = -EEXIST;
4610         return err;
4611 }
4612 
4613 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4614                         int mode, dev_t rdev)
4615 {
4616         struct btrfs_trans_handle *trans;
4617         struct btrfs_root *root = BTRFS_I(dir)->root;
4618         struct inode *inode = NULL;
4619         int err;
4620         int drop_inode = 0;
4621         u64 objectid;
4622         unsigned long nr = 0;
4623         u64 index = 0;
4624 
4625         if (!new_valid_dev(rdev))
4626                 return -EINVAL;
4627 
4628         /*
4629          * 2 for inode item and ref
4630          * 2 for dir items
4631          * 1 for xattr if selinux is on
4632          */
4633         trans = btrfs_start_transaction(root, 5);
4634         if (IS_ERR(trans))
4635                 return PTR_ERR(trans);
4636 
4637         err = btrfs_find_free_ino(root, &objectid);
4638         if (err)
4639                 goto out_unlock;
4640 
4641         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4642                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4643                                 mode, &index);
4644         if (IS_ERR(inode)) {
4645                 err = PTR_ERR(inode);
4646                 goto out_unlock;
4647         }
4648 
4649         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4650         if (err) {
4651                 drop_inode = 1;
4652                 goto out_unlock;
4653         }
4654 
4655         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4656         if (err)
4657                 drop_inode = 1;
4658         else {
4659                 inode->i_op = &btrfs_special_inode_operations;
4660                 init_special_inode(inode, inode->i_mode, rdev);
4661                 btrfs_update_inode(trans, root, inode);
4662         }
4663 out_unlock:
4664         nr = trans->blocks_used;
4665         btrfs_end_transaction_throttle(trans, root);
4666         btrfs_btree_balance_dirty(root, nr);
4667         if (drop_inode) {
4668                 inode_dec_link_count(inode);
4669                 iput(inode);
4670         }
4671         return err;
4672 }
4673 
4674 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4675                         int mode, struct nameidata *nd)
4676 {
4677         struct btrfs_trans_handle *trans;
4678         struct btrfs_root *root = BTRFS_I(dir)->root;
4679         struct inode *inode = NULL;
4680         int drop_inode = 0;
4681         int err;
4682         unsigned long nr = 0;
4683         u64 objectid;
4684         u64 index = 0;
4685 
4686         /*
4687          * 2 for inode item and ref
4688          * 2 for dir items
4689          * 1 for xattr if selinux is on
4690          */
4691         trans = btrfs_start_transaction(root, 5);
4692         if (IS_ERR(trans))
4693                 return PTR_ERR(trans);
4694 
4695         err = btrfs_find_free_ino(root, &objectid);
4696         if (err)
4697                 goto out_unlock;
4698 
4699         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4700                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4701                                 mode, &index);
4702         if (IS_ERR(inode)) {
4703                 err = PTR_ERR(inode);
4704                 goto out_unlock;
4705         }
4706 
4707         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4708         if (err) {
4709                 drop_inode = 1;
4710                 goto out_unlock;
4711         }
4712 
4713         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4714         if (err)
4715                 drop_inode = 1;
4716         else {
4717                 inode->i_mapping->a_ops = &btrfs_aops;
4718                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4719                 inode->i_fop = &btrfs_file_operations;
4720                 inode->i_op = &btrfs_file_inode_operations;
4721                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4722         }
4723 out_unlock:
4724         nr = trans->blocks_used;
4725         btrfs_end_transaction_throttle(trans, root);
4726         if (drop_inode) {
4727                 inode_dec_link_count(inode);
4728                 iput(inode);
4729         }
4730         btrfs_btree_balance_dirty(root, nr);
4731         return err;
4732 }
4733 
4734 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
4735                       struct dentry *dentry)
4736 {
4737         struct btrfs_trans_handle *trans;
4738         struct btrfs_root *root = BTRFS_I(dir)->root;
4739         struct inode *inode = old_dentry->d_inode;
4740         u64 index;
4741         unsigned long nr = 0;
4742         int err;
4743         int drop_inode = 0;
4744 
4745         /* do not allow sys_link's with other subvols of the same device */
4746         if (root->objectid != BTRFS_I(inode)->root->objectid)
4747                 return -EXDEV;
4748 
4749         if (inode->i_nlink == ~0U)
4750                 return -EMLINK;
4751 
4752         err = btrfs_set_inode_index(dir, &index);
4753         if (err)
4754                 goto fail;
4755 
4756         /*
4757          * 2 items for inode and inode ref
4758          * 2 items for dir items
4759          * 1 item for parent inode
4760          */
4761         trans = btrfs_start_transaction(root, 5);
4762         if (IS_ERR(trans)) {
4763                 err = PTR_ERR(trans);
4764                 goto fail;
4765         }
4766 
4767         btrfs_inc_nlink(inode);
4768         inode->i_ctime = CURRENT_TIME;
4769         ihold(inode);
4770 
4771         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
4772 
4773         if (err) {
4774                 drop_inode = 1;
4775         } else {
4776                 struct dentry *parent = dget_parent(dentry);
4777                 err = btrfs_update_inode(trans, root, inode);
4778                 BUG_ON(err);
4779                 btrfs_log_new_name(trans, inode, NULL, parent);
4780                 dput(parent);
4781         }
4782 
4783         nr = trans->blocks_used;
4784         btrfs_end_transaction_throttle(trans, root);
4785 fail:
4786         if (drop_inode) {
4787                 inode_dec_link_count(inode);
4788                 iput(inode);
4789         }
4790         btrfs_btree_balance_dirty(root, nr);
4791         return err;
4792 }
4793 
4794 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
4795 {
4796         struct inode *inode = NULL;
4797         struct btrfs_trans_handle *trans;
4798         struct btrfs_root *root = BTRFS_I(dir)->root;
4799         int err = 0;
4800         int drop_on_err = 0;
4801         u64 objectid = 0;
4802         u64 index = 0;
4803         unsigned long nr = 1;
4804 
4805         /*
4806          * 2 items for inode and ref
4807          * 2 items for dir items
4808          * 1 for xattr if selinux is on
4809          */
4810         trans = btrfs_start_transaction(root, 5);
4811         if (IS_ERR(trans))
4812                 return PTR_ERR(trans);
4813 
4814         err = btrfs_find_free_ino(root, &objectid);
4815         if (err)
4816                 goto out_fail;
4817 
4818         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4819                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4820                                 S_IFDIR | mode, &index);
4821         if (IS_ERR(inode)) {
4822                 err = PTR_ERR(inode);
4823                 goto out_fail;
4824         }
4825 
4826         drop_on_err = 1;
4827 
4828         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4829         if (err)
4830                 goto out_fail;
4831 
4832         inode->i_op = &btrfs_dir_inode_operations;
4833         inode->i_fop = &btrfs_dir_file_operations;
4834 
4835         btrfs_i_size_write(inode, 0);
4836         err = btrfs_update_inode(trans, root, inode);
4837         if (err)
4838                 goto out_fail;
4839 
4840         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
4841                              dentry->d_name.len, 0, index);
4842         if (err)
4843                 goto out_fail;
4844 
4845         d_instantiate(dentry, inode);
4846         drop_on_err = 0;
4847 
4848 out_fail:
4849         nr = trans->blocks_used;
4850         btrfs_end_transaction_throttle(trans, root);
4851         if (drop_on_err)
4852                 iput(inode);
4853         btrfs_btree_balance_dirty(root, nr);
4854         return err;
4855 }
4856 
4857 /* helper for btfs_get_extent.  Given an existing extent in the tree,
4858  * and an extent that you want to insert, deal with overlap and insert
4859  * the new extent into the tree.
4860  */
4861 static int merge_extent_mapping(struct extent_map_tree *em_tree,
4862                                 struct extent_map *existing,
4863                                 struct extent_map *em,
4864                                 u64 map_start, u64 map_len)
4865 {
4866         u64 start_diff;
4867 
4868         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
4869         start_diff = map_start - em->start;
4870         em->start = map_start;
4871         em->len = map_len;
4872         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
4873             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
4874                 em->block_start += start_diff;
4875                 em->block_len -= start_diff;
4876         }
4877         return add_extent_mapping(em_tree, em);
4878 }
4879 
4880 static noinline int uncompress_inline(struct btrfs_path *path,
4881                                       struct inode *inode, struct page *page,
4882                                       size_t pg_offset, u64 extent_offset,
4883                                       struct btrfs_file_extent_item *item)
4884 {
4885         int ret;
4886         struct extent_buffer *leaf = path->nodes[0];
4887         char *tmp;
4888         size_t max_size;
4889         unsigned long inline_size;
4890         unsigned long ptr;
4891         int compress_type;
4892 
4893         WARN_ON(pg_offset != 0);
4894         compress_type = btrfs_file_extent_compression(leaf, item);
4895         max_size = btrfs_file_extent_ram_bytes(leaf, item);
4896         inline_size = btrfs_file_extent_inline_item_len(leaf,
4897                                         btrfs_item_nr(leaf, path->slots[0]));
4898         tmp = kmalloc(inline_size, GFP_NOFS);
4899         if (!tmp)
4900                 return -ENOMEM;
4901         ptr = btrfs_file_extent_inline_start(item);
4902 
4903         read_extent_buffer(leaf, tmp, ptr, inline_size);
4904 
4905         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
4906         ret = btrfs_decompress(compress_type, tmp, page,
4907                                extent_offset, inline_size, max_size);
4908         if (ret) {
4909                 char *kaddr = kmap_atomic(page, KM_USER0);
4910                 unsigned long copy_size = min_t(u64,
4911                                   PAGE_CACHE_SIZE - pg_offset,
4912                                   max_size - extent_offset);
4913                 memset(kaddr + pg_offset, 0, copy_size);
4914                 kunmap_atomic(kaddr, KM_USER0);
4915         }
4916         kfree(tmp);
4917         return 0;
4918 }
4919 
4920 /*
4921  * a bit scary, this does extent mapping from logical file offset to the disk.
4922  * the ugly parts come from merging extents from the disk with the in-ram
4923  * representation.  This gets more complex because of the data=ordered code,
4924  * where the in-ram extents might be locked pending data=ordered completion.
4925  *
4926  * This also copies inline extents directly into the page.
4927  */
4928 
4929 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
4930                                     size_t pg_offset, u64 start, u64 len,
4931                                     int create)
4932 {
4933         int ret;
4934         int err = 0;
4935         u64 bytenr;
4936         u64 extent_start = 0;
4937         u64 extent_end = 0;
4938         u64 objectid = btrfs_ino(inode);
4939         u32 found_type;
4940         struct btrfs_path *path = NULL;
4941         struct btrfs_root *root = BTRFS_I(inode)->root;
4942         struct btrfs_file_extent_item *item;
4943         struct extent_buffer *leaf;
4944         struct btrfs_key found_key;
4945         struct extent_map *em = NULL;
4946         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4947         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4948         struct btrfs_trans_handle *trans = NULL;
4949         int compress_type;
4950 
4951 again:
4952         read_lock(&em_tree->lock);
4953         em = lookup_extent_mapping(em_tree, start, len);
4954         if (em)
4955                 em->bdev = root->fs_info->fs_devices->latest_bdev;
4956         read_unlock(&em_tree->lock);
4957 
4958         if (em) {
4959                 if (em->start > start || em->start + em->len <= start)
4960                         free_extent_map(em);
4961                 else if (em->block_start == EXTENT_MAP_INLINE && page)
4962                         free_extent_map(em);
4963                 else
4964                         goto out;
4965         }
4966         em = alloc_extent_map();
4967         if (!em) {
4968                 err = -ENOMEM;
4969                 goto out;
4970         }
4971         em->bdev = root->fs_info->fs_devices->latest_bdev;
4972         em->start = EXTENT_MAP_HOLE;
4973         em->orig_start = EXTENT_MAP_HOLE;
4974         em->len = (u64)-1;
4975         em->block_len = (u64)-1;
4976 
4977         if (!path) {
4978                 path = btrfs_alloc_path();
4979                 if (!path) {
4980                         err = -ENOMEM;
4981                         goto out;
4982                 }
4983                 /*
4984                  * Chances are we'll be called again, so go ahead and do
4985                  * readahead
4986                  */
4987                 path->reada = 1;
4988         }
4989 
4990         ret = btrfs_lookup_file_extent(trans, root, path,
4991                                        objectid, start, trans != NULL);
4992         if (ret < 0) {
4993                 err = ret;
4994                 goto out;
4995         }
4996 
4997         if (ret != 0) {
4998                 if (path->slots[0] == 0)
4999                         goto not_found;
5000                 path->slots[0]--;
5001         }
5002 
5003         leaf = path->nodes[0];
5004         item = btrfs_item_ptr(leaf, path->slots[0],
5005                               struct btrfs_file_extent_item);
5006         /* are we inside the extent that was found? */
5007         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5008         found_type = btrfs_key_type(&found_key);
5009         if (found_key.objectid != objectid ||
5010             found_type != BTRFS_EXTENT_DATA_KEY) {
5011                 goto not_found;
5012         }
5013 
5014         found_type = btrfs_file_extent_type(leaf, item);
5015         extent_start = found_key.offset;
5016         compress_type = btrfs_file_extent_compression(leaf, item);
5017         if (found_type == BTRFS_FILE_EXTENT_REG ||
5018             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5019                 extent_end = extent_start +
5020                        btrfs_file_extent_num_bytes(leaf, item);
5021         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5022                 size_t size;
5023                 size = btrfs_file_extent_inline_len(leaf, item);
5024                 extent_end = (extent_start + size + root->sectorsize - 1) &
5025                         ~((u64)root->sectorsize - 1);
5026         }
5027 
5028         if (start >= extent_end) {
5029                 path->slots[0]++;
5030                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
5031                         ret = btrfs_next_leaf(root, path);
5032                         if (ret < 0) {
5033                                 err = ret;
5034                                 goto out;
5035                         }
5036                         if (ret > 0)
5037                                 goto not_found;
5038                         leaf = path->nodes[0];
5039                 }
5040                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5041                 if (found_key.objectid != objectid ||
5042                     found_key.type != BTRFS_EXTENT_DATA_KEY)
5043                         goto not_found;
5044                 if (start + len <= found_key.offset)
5045                         goto not_found;
5046                 em->start = start;
5047                 em->len = found_key.offset - start;
5048                 goto not_found_em;
5049         }
5050 
5051         if (found_type == BTRFS_FILE_EXTENT_REG ||
5052             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5053                 em->start = extent_start;
5054                 em->len = extent_end - extent_start;
5055                 em->orig_start = extent_start -
5056                                  btrfs_file_extent_offset(leaf, item);
5057                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
5058                 if (bytenr == 0) {
5059                         em->block_start = EXTENT_MAP_HOLE;
5060                         goto insert;
5061                 }
5062                 if (compress_type != BTRFS_COMPRESS_NONE) {
5063                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5064                         em->compress_type = compress_type;
5065                         em->block_start = bytenr;
5066                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
5067                                                                          item);
5068                 } else {
5069                         bytenr += btrfs_file_extent_offset(leaf, item);
5070                         em->block_start = bytenr;
5071                         em->block_len = em->len;
5072                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
5073                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
5074                 }
5075                 goto insert;
5076         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5077                 unsigned long ptr;
5078                 char *map;
5079                 size_t size;
5080                 size_t extent_offset;
5081                 size_t copy_size;
5082 
5083                 em->block_start = EXTENT_MAP_INLINE;
5084                 if (!page || create) {
5085                         em->start = extent_start;
5086                         em->len = extent_end - extent_start;
5087                         goto out;
5088                 }
5089 
5090                 size = btrfs_file_extent_inline_len(leaf, item);
5091                 extent_offset = page_offset(page) + pg_offset - extent_start;
5092                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
5093                                 size - extent_offset);
5094                 em->start = extent_start + extent_offset;
5095                 em->len = (copy_size + root->sectorsize - 1) &
5096                         ~((u64)root->sectorsize - 1);
5097                 em->orig_start = EXTENT_MAP_INLINE;
5098                 if (compress_type) {
5099                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5100                         em->compress_type = compress_type;
5101                 }
5102                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
5103                 if (create == 0 && !PageUptodate(page)) {
5104                         if (btrfs_file_extent_compression(leaf, item) !=
5105                             BTRFS_COMPRESS_NONE) {
5106                                 ret = uncompress_inline(path, inode, page,
5107                                                         pg_offset,
5108                                                         extent_offset, item);
5109                                 BUG_ON(ret);
5110                         } else {
5111                                 map = kmap(page);
5112                                 read_extent_buffer(leaf, map + pg_offset, ptr,
5113                                                    copy_size);
5114                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
5115                                         memset(map + pg_offset + copy_size, 0,
5116                                                PAGE_CACHE_SIZE - pg_offset -
5117                                                copy_size);
5118                                 }
5119                                 kunmap(page);
5120                         }
5121                         flush_dcache_page(page);
5122                 } else if (create && PageUptodate(page)) {
5123                         WARN_ON(1);
5124                         if (!trans) {
5125                                 kunmap(page);
5126                                 free_extent_map(em);
5127                                 em = NULL;
5128 
5129                                 btrfs_release_path(path);
5130                                 trans = btrfs_join_transaction(root);
5131 
5132                                 if (IS_ERR(trans))
5133                                         return ERR_CAST(trans);
5134                                 goto again;
5135                         }
5136                         map = kmap(page);
5137                         write_extent_buffer(leaf, map + pg_offset, ptr,
5138                                             copy_size);
5139                         kunmap(page);
5140                         btrfs_mark_buffer_dirty(leaf);
5141                 }
5142                 set_extent_uptodate(io_tree, em->start,
5143                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
5144                 goto insert;
5145         } else {
5146                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
5147                 WARN_ON(1);
5148         }
5149 not_found:
5150         em->start = start;
5151         em->len = len;
5152 not_found_em:
5153         em->block_start = EXTENT_MAP_HOLE;
5154         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
5155 insert:
5156         btrfs_release_path(path);
5157         if (em->start > start || extent_map_end(em) <= start) {
5158                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
5159                        "[%llu %llu]\n", (unsigned long long)em->start,
5160                        (unsigned long long)em->len,
5161                        (unsigned long long)start,
5162                        (unsigned long long)len);
5163                 err = -EIO;
5164                 goto out;
5165         }
5166 
5167         err = 0;
5168         write_lock(&em_tree->lock);
5169         ret = add_extent_mapping(em_tree, em);
5170         /* it is possible that someone inserted the extent into the tree
5171          * while we had the lock dropped.  It is also possible that
5172          * an overlapping map exists in the tree
5173          */
5174         if (ret == -EEXIST) {
5175                 struct extent_map *existing;
5176 
5177                 ret = 0;
5178 
5179                 existing = lookup_extent_mapping(em_tree, start, len);
5180                 if (existing && (existing->start > start ||
5181                     existing->start + existing->len <= start)) {
5182                         free_extent_map(existing);
5183                         existing = NULL;
5184                 }
5185                 if (!existing) {
5186                         existing = lookup_extent_mapping(em_tree, em->start,
5187                                                          em->len);
5188                         if (existing) {
5189                                 err = merge_extent_mapping(em_tree, existing,
5190                                                            em, start,
5191                                                            root->sectorsize);
5192                                 free_extent_map(existing);
5193                                 if (err) {
5194                                         free_extent_map(em);
5195                                         em = NULL;
5196                                 }
5197                         } else {
5198                                 err = -EIO;
5199                                 free_extent_map(em);
5200                                 em = NULL;
5201                         }
5202                 } else {
5203                         free_extent_map(em);
5204                         em = existing;
5205                         err = 0;
5206                 }
5207         }
5208         write_unlock(&em_tree->lock);
5209 out:
5210 
5211         trace_btrfs_get_extent(root, em);
5212 
5213         if (path)
5214                 btrfs_free_path(path);
5215         if (trans) {
5216                 ret = btrfs_end_transaction(trans, root);
5217                 if (!err)
5218                         err = ret;
5219         }
5220         if (err) {
5221                 free_extent_map(em);
5222                 return ERR_PTR(err);
5223         }
5224         return em;
5225 }
5226 
5227 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
5228                                            size_t pg_offset, u64 start, u64 len,
5229                                            int create)
5230 {
5231         struct extent_map *em;
5232         struct extent_map *hole_em = NULL;
5233         u64 range_start = start;
5234         u64 end;
5235         u64 found;
5236         u64 found_end;
5237         int err = 0;
5238 
5239         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
5240         if (IS_ERR(em))
5241                 return em;
5242         if (em) {
5243                 /*
5244                  * if our em maps to a hole, there might
5245                  * actually be delalloc bytes behind it
5246                  */
5247                 if (em->block_start != EXTENT_MAP_HOLE)
5248                         return em;
5249                 else
5250                         hole_em = em;
5251         }
5252 
5253         /* check to see if we've wrapped (len == -1 or similar) */
5254         end = start + len;
5255         if (end < start)
5256                 end = (u64)-1;
5257         else
5258                 end -= 1;
5259 
5260         em = NULL;
5261 
5262         /* ok, we didn't find anything, lets look for delalloc */
5263         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
5264                                  end, len, EXTENT_DELALLOC, 1);
5265         found_end = range_start + found;
5266         if (found_end < range_start)
5267                 found_end = (u64)-1;
5268 
5269         /*
5270          * we didn't find anything useful, return
5271          * the original results from get_extent()
5272          */
5273         if (range_start > end || found_end <= start) {
5274                 em = hole_em;
5275                 hole_em = NULL;
5276                 goto out;
5277         }
5278 
5279         /* adjust the range_start to make sure it doesn't
5280          * go backwards from the start they passed in
5281          */
5282         range_start = max(start,range_start);
5283         found = found_end - range_start;
5284 
5285         if (found > 0) {
5286                 u64 hole_start = start;
5287                 u64 hole_len = len;
5288 
5289                 em = alloc_extent_map();
5290                 if (!em) {
5291                         err = -ENOMEM;
5292                         goto out;
5293                 }
5294                 /*
5295                  * when btrfs_get_extent can't find anything it
5296                  * returns one huge hole
5297                  *
5298                  * make sure what it found really fits our range, and
5299                  * adjust to make sure it is based on the start from
5300                  * the caller
5301                  */
5302                 if (hole_em) {
5303                         u64 calc_end = extent_map_end(hole_em);
5304 
5305                         if (calc_end <= start || (hole_em->start > end)) {
5306                                 free_extent_map(hole_em);
5307                                 hole_em = NULL;
5308                         } else {
5309                                 hole_start = max(hole_em->start, start);
5310                                 hole_len = calc_end - hole_start;
5311                         }
5312                 }
5313                 em->bdev = NULL;
5314                 if (hole_em && range_start > hole_start) {
5315                         /* our hole starts before our delalloc, so we
5316                          * have to return just the parts of the hole
5317                          * that go until  the delalloc starts
5318                          */
5319                         em->len = min(hole_len,
5320                                       range_start - hole_start);
5321                         em->start = hole_start;
5322                         em->orig_start = hole_start;
5323                         /*
5324                          * don't adjust block start at all,
5325                          * it is fixed at EXTENT_MAP_HOLE
5326                          */
5327                         em->block_start = hole_em->block_start;
5328                         em->block_len = hole_len;
5329                 } else {
5330                         em->start = range_start;
5331                         em->len = found;
5332                         em->orig_start = range_start;
5333                         em->block_start = EXTENT_MAP_DELALLOC;
5334                         em->block_len = found;
5335                 }
5336         } else if (hole_em) {
5337                 return hole_em;
5338         }
5339 out:
5340 
5341         free_extent_map(hole_em);
5342         if (err) {
5343                 free_extent_map(em);
5344                 return ERR_PTR(err);
5345         }
5346         return em;
5347 }
5348 
5349 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
5350                                                   struct extent_map *em,
5351                                                   u64 start, u64 len)
5352 {
5353         struct btrfs_root *root = BTRFS_I(inode)->root;
5354         struct btrfs_trans_handle *trans;
5355         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5356         struct btrfs_key ins;
5357         u64 alloc_hint;
5358         int ret;
5359         bool insert = false;
5360 
5361         /*
5362          * Ok if the extent map we looked up is a hole and is for the exact
5363          * range we want, there is no reason to allocate a new one, however if
5364          * it is not right then we need to free this one and drop the cache for
5365          * our range.
5366          */
5367         if (em->block_start != EXTENT_MAP_HOLE || em->start != start ||
5368             em->len != len) {
5369                 free_extent_map(em);
5370                 em = NULL;
5371                 insert = true;
5372                 btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
5373         }
5374 
5375         trans = btrfs_join_transaction(root);
5376         if (IS_ERR(trans))
5377                 return ERR_CAST(trans);
5378 
5379         if (start <= BTRFS_I(inode)->disk_i_size && len < 64 * 1024)
5380                 btrfs_add_inode_defrag(trans, inode);
5381 
5382         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5383 
5384         alloc_hint = get_extent_allocation_hint(inode, start, len);
5385         ret = btrfs_reserve_extent(trans, root, len, root->sectorsize, 0,
5386                                    alloc_hint, (u64)-1, &ins, 1);
5387         if (ret) {
5388                 em = ERR_PTR(ret);
5389                 goto out;
5390         }
5391 
5392         if (!em) {
5393                 em = alloc_extent_map();
5394                 if (!em) {
5395                         em = ERR_PTR(-ENOMEM);
5396                         goto out;
5397                 }
5398         }
5399 
5400         em->start = start;
5401         em->orig_start = em->start;
5402         em->len = ins.offset;
5403 
5404         em->block_start = ins.objectid;
5405         em->block_len = ins.offset;
5406         em->bdev = root->fs_info->fs_devices->latest_bdev;
5407 
5408         /*
5409          * We need to do this because if we're using the original em we searched
5410          * for, we could have EXTENT_FLAG_VACANCY set, and we don't want that.
5411          */
5412         em->flags = 0;
5413         set_bit(EXTENT_FLAG_PINNED, &em->flags);
5414 
5415         while (insert) {
5416                 write_lock(&em_tree->lock);
5417                 ret = add_extent_mapping(em_tree, em);
5418                 write_unlock(&em_tree->lock);
5419                 if (ret != -EEXIST)
5420                         break;
5421                 btrfs_drop_extent_cache(inode, start, start + em->len - 1, 0);
5422         }
5423 
5424         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
5425                                            ins.offset, ins.offset, 0);
5426         if (ret) {
5427                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
5428                 em = ERR_PTR(ret);
5429         }
5430 out:
5431         btrfs_end_transaction(trans, root);
5432         return em;
5433 }
5434 
5435 /*
5436  * returns 1 when the nocow is safe, < 1 on error, 0 if the
5437  * block must be cow'd
5438  */
5439 static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
5440                                       struct inode *inode, u64 offset, u64 len)
5441 {
5442         struct btrfs_path *path;
5443         int ret;
5444         struct extent_buffer *leaf;
5445         struct btrfs_root *root = BTRFS_I(inode)->root;
5446         struct btrfs_file_extent_item *fi;
5447         struct btrfs_key key;
5448         u64 disk_bytenr;
5449         u64 backref_offset;
5450         u64 extent_end;
5451         u64 num_bytes;
5452         int slot;
5453         int found_type;
5454 
5455         path = btrfs_alloc_path();
5456         if (!path)
5457                 return -ENOMEM;
5458 
5459         ret = btrfs_lookup_file_extent(trans, root, path, btrfs_ino(inode),
5460                                        offset, 0);
5461         if (ret < 0)
5462                 goto out;
5463 
5464         slot = path->slots[0];
5465         if (ret == 1) {
5466                 if (slot == 0) {
5467                         /* can't find the item, must cow */
5468                         ret = 0;
5469                         goto out;
5470                 }
5471                 slot--;
5472         }
5473         ret = 0;
5474         leaf = path->nodes[0];
5475         btrfs_item_key_to_cpu(leaf, &key, slot);
5476         if (key.objectid != btrfs_ino(inode) ||
5477             key.type != BTRFS_EXTENT_DATA_KEY) {
5478                 /* not our file or wrong item type, must cow */
5479                 goto out;
5480         }
5481 
5482         if (key.offset > offset) {
5483                 /* Wrong offset, must cow */
5484                 goto out;
5485         }
5486 
5487         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5488         found_type = btrfs_file_extent_type(leaf, fi);
5489         if (found_type != BTRFS_FILE_EXTENT_REG &&
5490             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
5491                 /* not a regular extent, must cow */
5492                 goto out;
5493         }
5494         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5495         backref_offset = btrfs_file_extent_offset(leaf, fi);
5496 
5497         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
5498         if (extent_end < offset + len) {
5499                 /* extent doesn't include our full range, must cow */
5500                 goto out;
5501         }
5502 
5503         if (btrfs_extent_readonly(root, disk_bytenr))
5504                 goto out;
5505 
5506         /*
5507          * look for other files referencing this extent, if we
5508          * find any we must cow
5509          */
5510         if (btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
5511                                   key.offset - backref_offset, disk_bytenr))
5512                 goto out;
5513 
5514         /*
5515          * adjust disk_bytenr and num_bytes to cover just the bytes
5516          * in this extent we are about to write.  If there
5517          * are any csums in that range we have to cow in order
5518          * to keep the csums correct
5519          */
5520         disk_bytenr += backref_offset;
5521         disk_bytenr += offset - key.offset;
5522         num_bytes = min(offset + len, extent_end) - offset;
5523         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
5524                                 goto out;
5525         /*
5526          * all of the above have passed, it is safe to overwrite this extent
5527          * without cow
5528          */
5529         ret = 1;
5530 out:
5531         btrfs_free_path(path);
5532         return ret;
5533 }
5534 
5535 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
5536                                    struct buffer_head *bh_result, int create)
5537 {
5538         struct extent_map *em;
5539         struct btrfs_root *root = BTRFS_I(inode)->root;
5540         u64 start = iblock << inode->i_blkbits;
5541         u64 len = bh_result->b_size;
5542         struct btrfs_trans_handle *trans;
5543 
5544         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
5545         if (IS_ERR(em))
5546                 return PTR_ERR(em);
5547 
5548         /*
5549          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
5550          * io.  INLINE is special, and we could probably kludge it in here, but
5551          * it's still buffered so for safety lets just fall back to the generic
5552          * buffered path.
5553          *
5554          * For COMPRESSED we _have_ to read the entire extent in so we can
5555          * decompress it, so there will be buffering required no matter what we
5556          * do, so go ahead and fallback to buffered.
5557          *
5558          * We return -ENOTBLK because thats what makes DIO go ahead and go back
5559          * to buffered IO.  Don't blame me, this is the price we pay for using
5560          * the generic code.
5561          */
5562         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
5563             em->block_start == EXTENT_MAP_INLINE) {
5564                 free_extent_map(em);
5565                 return -ENOTBLK;
5566         }
5567 
5568         /* Just a good old fashioned hole, return */
5569         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
5570                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
5571                 free_extent_map(em);
5572                 /* DIO will do one hole at a time, so just unlock a sector */
5573                 unlock_extent(&BTRFS_I(inode)->io_tree, start,
5574                               start + root->sectorsize - 1, GFP_NOFS);
5575                 return 0;
5576         }
5577 
5578         /*
5579          * We don't allocate a new extent in the following cases
5580          *
5581          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
5582          * existing extent.
5583          * 2) The extent is marked as PREALLOC.  We're good to go here and can
5584          * just use the extent.
5585          *
5586          */
5587         if (!create) {
5588                 len = em->len - (start - em->start);
5589                 goto map;
5590         }
5591 
5592         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
5593             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
5594              em->block_start != EXTENT_MAP_HOLE)) {
5595                 int type;
5596                 int ret;
5597                 u64 block_start;
5598 
5599                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5600                         type = BTRFS_ORDERED_PREALLOC;
5601                 else
5602                         type = BTRFS_ORDERED_NOCOW;
5603                 len = min(len, em->len - (start - em->start));
5604                 block_start = em->block_start + (start - em->start);
5605 
5606                 /*
5607                  * we're not going to log anything, but we do need
5608                  * to make sure the current transaction stays open
5609                  * while we look for nocow cross refs
5610                  */
5611                 trans = btrfs_join_transaction(root);
5612                 if (IS_ERR(trans))
5613                         goto must_cow;
5614 
5615                 if (can_nocow_odirect(trans, inode, start, len) == 1) {
5616                         ret = btrfs_add_ordered_extent_dio(inode, start,
5617                                            block_start, len, len, type);
5618                         btrfs_end_transaction(trans, root);
5619                         if (ret) {
5620                                 free_extent_map(em);
5621                                 return ret;
5622                         }
5623                         goto unlock;
5624                 }
5625                 btrfs_end_transaction(trans, root);
5626         }
5627 must_cow:
5628         /*
5629          * this will cow the extent, reset the len in case we changed
5630          * it above
5631          */
5632         len = bh_result->b_size;
5633         em = btrfs_new_extent_direct(inode, em, start, len);
5634         if (IS_ERR(em))
5635                 return PTR_ERR(em);
5636         len = min(len, em->len - (start - em->start));
5637 unlock:
5638         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, start + len - 1,
5639                           EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DIRTY, 1,
5640                           0, NULL, GFP_NOFS);
5641 map:
5642         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
5643                 inode->i_blkbits;
5644         bh_result->b_size = len;
5645         bh_result->b_bdev = em->bdev;
5646         set_buffer_mapped(bh_result);
5647         if (create && !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5648                 set_buffer_new(bh_result);
5649 
5650         free_extent_map(em);
5651 
5652         return 0;
5653 }
5654 
5655 struct btrfs_dio_private {
5656         struct inode *inode;
5657         u64 logical_offset;
5658         u64 disk_bytenr;
5659         u64 bytes;
5660         u32 *csums;
5661         void *private;
5662 
5663         /* number of bios pending for this dio */
5664         atomic_t pending_bios;
5665 
5666         /* IO errors */
5667         int errors;
5668 
5669         struct bio *orig_bio;
5670 };
5671 
5672 static void btrfs_endio_direct_read(struct bio *bio, int err)
5673 {
5674         struct btrfs_dio_private *dip = bio->bi_private;
5675         struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
5676         struct bio_vec *bvec = bio->bi_io_vec;
5677         struct inode *inode = dip->inode;
5678         struct btrfs_root *root = BTRFS_I(inode)->root;
5679         u64 start;
5680         u32 *private = dip->csums;
5681 
5682         start = dip->logical_offset;
5683         do {
5684                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
5685                         struct page *page = bvec->bv_page;
5686                         char *kaddr;
5687                         u32 csum = ~(u32)0;
5688                         unsigned long flags;
5689 
5690                         local_irq_save(flags);
5691                         kaddr = kmap_atomic(page, KM_IRQ0);
5692                         csum = btrfs_csum_data(root, kaddr + bvec->bv_offset,
5693                                                csum, bvec->bv_len);
5694                         btrfs_csum_final(csum, (char *)&csum);
5695                         kunmap_atomic(kaddr, KM_IRQ0);
5696                         local_irq_restore(flags);
5697 
5698                         flush_dcache_page(bvec->bv_page);
5699                         if (csum != *private) {
5700                                 printk(KERN_ERR "btrfs csum failed ino %llu off"
5701                                       " %llu csum %u private %u\n",
5702                                       (unsigned long long)btrfs_ino(inode),
5703                                       (unsigned long long)start,
5704                                       csum, *private);
5705                                 err = -EIO;
5706                         }
5707                 }
5708 
5709                 start += bvec->bv_len;
5710                 private++;
5711                 bvec++;
5712         } while (bvec <= bvec_end);
5713 
5714         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
5715                       dip->logical_offset + dip->bytes - 1, GFP_NOFS);
5716         bio->bi_private = dip->private;
5717 
5718         kfree(dip->csums);
5719         kfree(dip);
5720 
5721         /* If we had a csum failure make sure to clear the uptodate flag */
5722         if (err)
5723                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
5724         dio_end_io(bio, err);
5725 }
5726 
5727 static void btrfs_endio_direct_write(struct bio *bio, int err)
5728 {
5729         struct btrfs_dio_private *dip = bio->bi_private;
5730         struct inode *inode = dip->inode;
5731         struct btrfs_root *root = BTRFS_I(inode)->root;
5732         struct btrfs_trans_handle *trans;
5733         struct btrfs_ordered_extent *ordered = NULL;
5734         struct extent_state *cached_state = NULL;
5735         u64 ordered_offset = dip->logical_offset;
5736         u64 ordered_bytes = dip->bytes;
5737         int ret;
5738 
5739         if (err)
5740                 goto out_done;
5741 again:
5742         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
5743                                                    &ordered_offset,
5744                                                    ordered_bytes);
5745         if (!ret)
5746                 goto out_test;
5747 
5748         BUG_ON(!ordered);
5749 
5750         trans = btrfs_join_transaction(root);
5751         if (IS_ERR(trans)) {
5752                 err = -ENOMEM;
5753                 goto out;
5754         }
5755         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5756 
5757         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags)) {
5758                 ret = btrfs_ordered_update_i_size(inode, 0, ordered);
5759                 if (!ret)
5760                         ret = btrfs_update_inode(trans, root, inode);
5761                 err = ret;
5762                 goto out;
5763         }
5764 
5765         lock_extent_bits(&BTRFS_I(inode)->io_tree, ordered->file_offset,
5766                          ordered->file_offset + ordered->len - 1, 0,
5767                          &cached_state, GFP_NOFS);
5768 
5769         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags)) {
5770                 ret = btrfs_mark_extent_written(trans, inode,
5771                                                 ordered->file_offset,
5772                                                 ordered->file_offset +
5773                                                 ordered->len);
5774                 if (ret) {
5775                         err = ret;
5776                         goto out_unlock;
5777                 }
5778         } else {
5779                 ret = insert_reserved_file_extent(trans, inode,
5780                                                   ordered->file_offset,
5781                                                   ordered->start,
5782                                                   ordered->disk_len,
5783                                                   ordered->len,
5784                                                   ordered->len,
5785                                                   0, 0, 0,
5786                                                   BTRFS_FILE_EXTENT_REG);
5787                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
5788                                    ordered->file_offset, ordered->len);
5789                 if (ret) {
5790                         err = ret;
5791                         WARN_ON(1);
5792                         goto out_unlock;
5793                 }
5794         }
5795 
5796         add_pending_csums(trans, inode, ordered->file_offset, &ordered->list);
5797         ret = btrfs_ordered_update_i_size(inode, 0, ordered);
5798         if (!ret)
5799                 btrfs_update_inode(trans, root, inode);
5800         ret = 0;
5801 out_unlock:
5802         unlock_extent_cached(&BTRFS_I(inode)->io_tree, ordered->file_offset,
5803                              ordered->file_offset + ordered->len - 1,
5804                              &cached_state, GFP_NOFS);
5805 out:
5806         btrfs_delalloc_release_metadata(inode, ordered->len);
5807         btrfs_end_transaction(trans, root);
5808         ordered_offset = ordered->file_offset + ordered->len;
5809         btrfs_put_ordered_extent(ordered);
5810         btrfs_put_ordered_extent(ordered);
5811 
5812 out_test:
5813         /*
5814          * our bio might span multiple ordered extents.  If we haven't
5815          * completed the accounting for the whole dio, go back and try again
5816          */
5817         if (ordered_offset < dip->logical_offset + dip->bytes) {
5818                 ordered_bytes = dip->logical_offset + dip->bytes -
5819                         ordered_offset;
5820                 goto again;
5821         }
5822 out_done:
5823         bio->bi_private = dip->private;
5824 
5825         kfree(dip->csums);
5826         kfree(dip);
5827 
5828         /* If we had an error make sure to clear the uptodate flag */
5829         if (err)
5830                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
5831         dio_end_io(bio, err);
5832 }
5833 
5834 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
5835                                     struct bio *bio, int mirror_num,
5836                                     unsigned long bio_flags, u64 offset)
5837 {
5838         int ret;
5839         struct btrfs_root *root = BTRFS_I(inode)->root;
5840         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
5841         BUG_ON(ret);
5842         return 0;
5843 }
5844 
5845 static void btrfs_end_dio_bio(struct bio *bio, int err)
5846 {
5847         struct btrfs_dio_private *dip = bio->bi_private;
5848 
5849         if (err) {
5850                 printk(KERN_ERR "btrfs direct IO failed ino %llu rw %lu "
5851                       "sector %#Lx len %u err no %d\n",
5852                       (unsigned long long)btrfs_ino(dip->inode), bio->bi_rw,
5853                       (unsigned long long)bio->bi_sector, bio->bi_size, err);
5854                 dip->errors = 1;
5855 
5856                 /*
5857                  * before atomic variable goto zero, we must make sure
5858                  * dip->errors is perceived to be set.
5859                  */
5860                 smp_mb__before_atomic_dec();
5861         }
5862 
5863         /* if there are more bios still pending for this dio, just exit */
5864         if (!atomic_dec_and_test(&dip->pending_bios))
5865                 goto out;
5866 
5867         if (dip->errors)
5868                 bio_io_error(dip->orig_bio);
5869         else {
5870                 set_bit(BIO_UPTODATE, &dip->orig_bio->bi_flags);
5871                 bio_endio(dip->orig_bio, 0);
5872         }
5873 out:
5874         bio_put(bio);
5875 }
5876 
5877 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
5878                                        u64 first_sector, gfp_t gfp_flags)
5879 {
5880         int nr_vecs = bio_get_nr_vecs(bdev);
5881         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
5882 }
5883 
5884 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
5885                                          int rw, u64 file_offset, int skip_sum,
5886                                          u32 *csums, int async_submit)
5887 {
5888         int write = rw & REQ_WRITE;
5889         struct btrfs_root *root = BTRFS_I(inode)->root;
5890         int ret;
5891 
5892         bio_get(bio);
5893         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
5894         if (ret)
5895                 goto err;
5896 
5897         if (skip_sum)
5898                 goto map;
5899 
5900         if (write && async_submit) {
5901                 ret = btrfs_wq_submit_bio(root->fs_info,
5902                                    inode, rw, bio, 0, 0,
5903                                    file_offset,
5904                                    __btrfs_submit_bio_start_direct_io,
5905                                    __btrfs_submit_bio_done);
5906                 goto err;
5907         } else if (write) {
5908                 /*
5909                  * If we aren't doing async submit, calculate the csum of the
5910                  * bio now.
5911                  */
5912                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
5913                 if (ret)
5914                         goto err;
5915         } else if (!skip_sum) {
5916                 ret = btrfs_lookup_bio_sums_dio(root, inode, bio,
5917                                           file_offset, csums);
5918                 if (ret)
5919                         goto err;
5920         }
5921 
5922 map:
5923         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
5924 err:
5925         bio_put(bio);
5926         return ret;
5927 }
5928 
5929 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
5930                                     int skip_sum)
5931 {
5932         struct inode *inode = dip->inode;
5933         struct btrfs_root *root = BTRFS_I(inode)->root;
5934         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
5935         struct bio *bio;
5936         struct bio *orig_bio = dip->orig_bio;
5937         struct bio_vec *bvec = orig_bio->bi_io_vec;
5938         u64 start_sector = orig_bio->bi_sector;
5939         u64 file_offset = dip->logical_offset;
5940         u64 submit_len = 0;
5941         u64 map_length;
5942         int nr_pages = 0;
5943         u32 *csums = dip->csums;
5944         int ret = 0;
5945         int async_submit = 0;
5946         int write = rw & REQ_WRITE;
5947 
5948         map_length = orig_bio->bi_size;
5949         ret = btrfs_map_block(map_tree, READ, start_sector << 9,
5950                               &map_length, NULL, 0);
5951         if (ret) {
5952                 bio_put(orig_bio);
5953                 return -EIO;
5954         }
5955 
5956         if (map_length >= orig_bio->bi_size) {
5957                 bio = orig_bio;
5958                 goto submit;
5959         }
5960 
5961         async_submit = 1;
5962         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
5963         if (!bio)
5964                 return -ENOMEM;
5965         bio->bi_private = dip;
5966         bio->bi_end_io = btrfs_end_dio_bio;
5967         atomic_inc(&dip->pending_bios);
5968 
5969         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
5970                 if (unlikely(map_length < submit_len + bvec->bv_len ||
5971                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
5972                                  bvec->bv_offset) < bvec->bv_len)) {
5973                         /*
5974                          * inc the count before we submit the bio so
5975                          * we know the end IO handler won't happen before
5976                          * we inc the count. Otherwise, the dip might get freed
5977                          * before we're done setting it up
5978                          */
5979                         atomic_inc(&dip->pending_bios);
5980                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
5981                                                      file_offset, skip_sum,
5982                                                      csums, async_submit);
5983                         if (ret) {
5984                                 bio_put(bio);
5985                                 atomic_dec(&dip->pending_bios);
5986                                 goto out_err;
5987                         }
5988 
5989                         /* Write's use the ordered csums */
5990                         if (!write && !skip_sum)
5991                                 csums = csums + nr_pages;
5992                         start_sector += submit_len >> 9;
5993                         file_offset += submit_len;
5994 
5995                         submit_len = 0;
5996                         nr_pages = 0;
5997 
5998                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
5999                                                   start_sector, GFP_NOFS);
6000                         if (!bio)
6001                                 goto out_err;
6002                         bio->bi_private = dip;
6003                         bio->bi_end_io = btrfs_end_dio_bio;
6004 
6005                         map_length = orig_bio->bi_size;
6006                         ret = btrfs_map_block(map_tree, READ, start_sector << 9,
6007                                               &map_length, NULL, 0);
6008                         if (ret) {
6009                                 bio_put(bio);
6010                                 goto out_err;
6011                         }
6012                 } else {
6013                         submit_len += bvec->bv_len;
6014                         nr_pages ++;
6015                         bvec++;
6016                 }
6017         }
6018 
6019 submit:
6020         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
6021                                      csums, async_submit);
6022         if (!ret)
6023                 return 0;
6024 
6025         bio_put(bio);
6026 out_err:
6027         dip->errors = 1;
6028         /*
6029          * before atomic variable goto zero, we must
6030          * make sure dip->errors is perceived to be set.
6031          */
6032         smp_mb__before_atomic_dec();
6033         if (atomic_dec_and_test(&dip->pending_bios))
6034                 bio_io_error(dip->orig_bio);
6035 
6036         /* bio_end_io() will handle error, so we needn't return it */
6037         return 0;
6038 }
6039 
6040 static void btrfs_submit_direct(int rw, struct bio *bio, struct inode *inode,
6041                                 loff_t file_offset)
6042 {
6043         struct btrfs_root *root = BTRFS_I(inode)->root;
6044         struct btrfs_dio_private *dip;
6045         struct bio_vec *bvec = bio->bi_io_vec;
6046         int skip_sum;
6047         int write = rw & REQ_WRITE;
6048         int ret = 0;
6049 
6050         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
6051 
6052         dip = kmalloc(sizeof(*dip), GFP_NOFS);
6053         if (!dip) {
6054                 ret = -ENOMEM;
6055                 goto free_ordered;
6056         }
6057         dip->csums = NULL;
6058 
6059         /* Write's use the ordered csum stuff, so we don't need dip->csums */
6060         if (!write && !skip_sum) {
6061                 dip->csums = kmalloc(sizeof(u32) * bio->bi_vcnt, GFP_NOFS);
6062                 if (!dip->csums) {
6063                         kfree(dip);
6064                         ret = -ENOMEM;
6065                         goto free_ordered;
6066                 }
6067         }
6068 
6069         dip->private = bio->bi_private;
6070         dip->inode = inode;
6071         dip->logical_offset = file_offset;
6072 
6073         dip->bytes = 0;
6074         do {
6075                 dip->bytes += bvec->bv_len;
6076                 bvec++;
6077         } while (bvec <= (bio->bi_io_vec + bio->bi_vcnt - 1));
6078 
6079         dip->disk_bytenr = (u64)bio->bi_sector << 9;
6080         bio->bi_private = dip;
6081         dip->errors = 0;
6082         dip->orig_bio = bio;
6083         atomic_set(&dip->pending_bios, 0);
6084 
6085         if (write)
6086                 bio->bi_end_io = btrfs_endio_direct_write;
6087         else
6088                 bio->bi_end_io = btrfs_endio_direct_read;
6089 
6090         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
6091         if (!ret)
6092                 return;
6093 free_ordered:
6094         /*
6095          * If this is a write, we need to clean up the reserved space and kill
6096          * the ordered extent.
6097          */
6098         if