Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
[pandora-kernel.git] / fs / btrfs / file.c
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18
19 #include <linux/fs.h>
20 #include <linux/pagemap.h>
21 #include <linux/highmem.h>
22 #include <linux/time.h>
23 #include <linux/init.h>
24 #include <linux/string.h>
25 #include <linux/backing-dev.h>
26 #include <linux/mpage.h>
27 #include <linux/falloc.h>
28 #include <linux/swap.h>
29 #include <linux/writeback.h>
30 #include <linux/statfs.h>
31 #include <linux/compat.h>
32 #include <linux/slab.h>
33 #include "ctree.h"
34 #include "disk-io.h"
35 #include "transaction.h"
36 #include "btrfs_inode.h"
37 #include "ioctl.h"
38 #include "print-tree.h"
39 #include "tree-log.h"
40 #include "locking.h"
41 #include "compat.h"
42
43
44 /* simple helper to fault in pages and copy.  This should go away
45  * and be replaced with calls into generic code.
46  */
47 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
48                                          size_t write_bytes,
49                                          struct page **prepared_pages,
50                                          struct iov_iter *i)
51 {
52         size_t copied = 0;
53         size_t total_copied = 0;
54         int pg = 0;
55         int offset = pos & (PAGE_CACHE_SIZE - 1);
56
57         while (write_bytes > 0) {
58                 size_t count = min_t(size_t,
59                                      PAGE_CACHE_SIZE - offset, write_bytes);
60                 struct page *page = prepared_pages[pg];
61                 /*
62                  * Copy data from userspace to the current page
63                  *
64                  * Disable pagefault to avoid recursive lock since
65                  * the pages are already locked
66                  */
67                 pagefault_disable();
68                 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
69                 pagefault_enable();
70
71                 /* Flush processor's dcache for this page */
72                 flush_dcache_page(page);
73
74                 /*
75                  * if we get a partial write, we can end up with
76                  * partially up to date pages.  These add
77                  * a lot of complexity, so make sure they don't
78                  * happen by forcing this copy to be retried.
79                  *
80                  * The rest of the btrfs_file_write code will fall
81                  * back to page at a time copies after we return 0.
82                  */
83                 if (!PageUptodate(page) && copied < count)
84                         copied = 0;
85
86                 iov_iter_advance(i, copied);
87                 write_bytes -= copied;
88                 total_copied += copied;
89
90                 /* Return to btrfs_file_aio_write to fault page */
91                 if (unlikely(copied == 0))
92                         break;
93
94                 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
95                         offset += copied;
96                 } else {
97                         pg++;
98                         offset = 0;
99                 }
100         }
101         return total_copied;
102 }
103
104 /*
105  * unlocks pages after btrfs_file_write is done with them
106  */
107 void btrfs_drop_pages(struct page **pages, size_t num_pages)
108 {
109         size_t i;
110         for (i = 0; i < num_pages; i++) {
111                 /* page checked is some magic around finding pages that
112                  * have been modified without going through btrfs_set_page_dirty
113                  * clear it here
114                  */
115                 ClearPageChecked(pages[i]);
116                 unlock_page(pages[i]);
117                 mark_page_accessed(pages[i]);
118                 page_cache_release(pages[i]);
119         }
120 }
121
122 /*
123  * after copy_from_user, pages need to be dirtied and we need to make
124  * sure holes are created between the current EOF and the start of
125  * any next extents (if required).
126  *
127  * this also makes the decision about creating an inline extent vs
128  * doing real data extents, marking pages dirty and delalloc as required.
129  */
130 int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
131                       struct page **pages, size_t num_pages,
132                       loff_t pos, size_t write_bytes,
133                       struct extent_state **cached)
134 {
135         int err = 0;
136         int i;
137         u64 num_bytes;
138         u64 start_pos;
139         u64 end_of_last_block;
140         u64 end_pos = pos + write_bytes;
141         loff_t isize = i_size_read(inode);
142
143         start_pos = pos & ~((u64)root->sectorsize - 1);
144         num_bytes = (write_bytes + pos - start_pos +
145                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
146
147         end_of_last_block = start_pos + num_bytes - 1;
148         err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
149                                         cached);
150         if (err)
151                 return err;
152
153         for (i = 0; i < num_pages; i++) {
154                 struct page *p = pages[i];
155                 SetPageUptodate(p);
156                 ClearPageChecked(p);
157                 set_page_dirty(p);
158         }
159
160         /*
161          * we've only changed i_size in ram, and we haven't updated
162          * the disk i_size.  There is no need to log the inode
163          * at this time.
164          */
165         if (end_pos > isize)
166                 i_size_write(inode, end_pos);
167         return 0;
168 }
169
170 /*
171  * this drops all the extents in the cache that intersect the range
172  * [start, end].  Existing extents are split as required.
173  */
174 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
175                             int skip_pinned)
176 {
177         struct extent_map *em;
178         struct extent_map *split = NULL;
179         struct extent_map *split2 = NULL;
180         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
181         u64 len = end - start + 1;
182         int ret;
183         int testend = 1;
184         unsigned long flags;
185         int compressed = 0;
186
187         WARN_ON(end < start);
188         if (end == (u64)-1) {
189                 len = (u64)-1;
190                 testend = 0;
191         }
192         while (1) {
193                 if (!split)
194                         split = alloc_extent_map(GFP_NOFS);
195                 if (!split2)
196                         split2 = alloc_extent_map(GFP_NOFS);
197                 BUG_ON(!split || !split2);
198
199                 write_lock(&em_tree->lock);
200                 em = lookup_extent_mapping(em_tree, start, len);
201                 if (!em) {
202                         write_unlock(&em_tree->lock);
203                         break;
204                 }
205                 flags = em->flags;
206                 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
207                         if (testend && em->start + em->len >= start + len) {
208                                 free_extent_map(em);
209                                 write_unlock(&em_tree->lock);
210                                 break;
211                         }
212                         start = em->start + em->len;
213                         if (testend)
214                                 len = start + len - (em->start + em->len);
215                         free_extent_map(em);
216                         write_unlock(&em_tree->lock);
217                         continue;
218                 }
219                 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
220                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
221                 remove_extent_mapping(em_tree, em);
222
223                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
224                     em->start < start) {
225                         split->start = em->start;
226                         split->len = start - em->start;
227                         split->orig_start = em->orig_start;
228                         split->block_start = em->block_start;
229
230                         if (compressed)
231                                 split->block_len = em->block_len;
232                         else
233                                 split->block_len = split->len;
234
235                         split->bdev = em->bdev;
236                         split->flags = flags;
237                         split->compress_type = em->compress_type;
238                         ret = add_extent_mapping(em_tree, split);
239                         BUG_ON(ret);
240                         free_extent_map(split);
241                         split = split2;
242                         split2 = NULL;
243                 }
244                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
245                     testend && em->start + em->len > start + len) {
246                         u64 diff = start + len - em->start;
247
248                         split->start = start + len;
249                         split->len = em->start + em->len - (start + len);
250                         split->bdev = em->bdev;
251                         split->flags = flags;
252                         split->compress_type = em->compress_type;
253
254                         if (compressed) {
255                                 split->block_len = em->block_len;
256                                 split->block_start = em->block_start;
257                                 split->orig_start = em->orig_start;
258                         } else {
259                                 split->block_len = split->len;
260                                 split->block_start = em->block_start + diff;
261                                 split->orig_start = split->start;
262                         }
263
264                         ret = add_extent_mapping(em_tree, split);
265                         BUG_ON(ret);
266                         free_extent_map(split);
267                         split = NULL;
268                 }
269                 write_unlock(&em_tree->lock);
270
271                 /* once for us */
272                 free_extent_map(em);
273                 /* once for the tree*/
274                 free_extent_map(em);
275         }
276         if (split)
277                 free_extent_map(split);
278         if (split2)
279                 free_extent_map(split2);
280         return 0;
281 }
282
283 /*
284  * this is very complex, but the basic idea is to drop all extents
285  * in the range start - end.  hint_block is filled in with a block number
286  * that would be a good hint to the block allocator for this file.
287  *
288  * If an extent intersects the range but is not entirely inside the range
289  * it is either truncated or split.  Anything entirely inside the range
290  * is deleted from the tree.
291  */
292 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
293                        u64 start, u64 end, u64 *hint_byte, int drop_cache)
294 {
295         struct btrfs_root *root = BTRFS_I(inode)->root;
296         struct extent_buffer *leaf;
297         struct btrfs_file_extent_item *fi;
298         struct btrfs_path *path;
299         struct btrfs_key key;
300         struct btrfs_key new_key;
301         u64 search_start = start;
302         u64 disk_bytenr = 0;
303         u64 num_bytes = 0;
304         u64 extent_offset = 0;
305         u64 extent_end = 0;
306         int del_nr = 0;
307         int del_slot = 0;
308         int extent_type;
309         int recow;
310         int ret;
311
312         if (drop_cache)
313                 btrfs_drop_extent_cache(inode, start, end - 1, 0);
314
315         path = btrfs_alloc_path();
316         if (!path)
317                 return -ENOMEM;
318
319         while (1) {
320                 recow = 0;
321                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
322                                                search_start, -1);
323                 if (ret < 0)
324                         break;
325                 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
326                         leaf = path->nodes[0];
327                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
328                         if (key.objectid == inode->i_ino &&
329                             key.type == BTRFS_EXTENT_DATA_KEY)
330                                 path->slots[0]--;
331                 }
332                 ret = 0;
333 next_slot:
334                 leaf = path->nodes[0];
335                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
336                         BUG_ON(del_nr > 0);
337                         ret = btrfs_next_leaf(root, path);
338                         if (ret < 0)
339                                 break;
340                         if (ret > 0) {
341                                 ret = 0;
342                                 break;
343                         }
344                         leaf = path->nodes[0];
345                         recow = 1;
346                 }
347
348                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
349                 if (key.objectid > inode->i_ino ||
350                     key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
351                         break;
352
353                 fi = btrfs_item_ptr(leaf, path->slots[0],
354                                     struct btrfs_file_extent_item);
355                 extent_type = btrfs_file_extent_type(leaf, fi);
356
357                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
358                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
359                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
360                         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
361                         extent_offset = btrfs_file_extent_offset(leaf, fi);
362                         extent_end = key.offset +
363                                 btrfs_file_extent_num_bytes(leaf, fi);
364                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
365                         extent_end = key.offset +
366                                 btrfs_file_extent_inline_len(leaf, fi);
367                 } else {
368                         WARN_ON(1);
369                         extent_end = search_start;
370                 }
371
372                 if (extent_end <= search_start) {
373                         path->slots[0]++;
374                         goto next_slot;
375                 }
376
377                 search_start = max(key.offset, start);
378                 if (recow) {
379                         btrfs_release_path(root, path);
380                         continue;
381                 }
382
383                 /*
384                  *     | - range to drop - |
385                  *  | -------- extent -------- |
386                  */
387                 if (start > key.offset && end < extent_end) {
388                         BUG_ON(del_nr > 0);
389                         BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
390
391                         memcpy(&new_key, &key, sizeof(new_key));
392                         new_key.offset = start;
393                         ret = btrfs_duplicate_item(trans, root, path,
394                                                    &new_key);
395                         if (ret == -EAGAIN) {
396                                 btrfs_release_path(root, path);
397                                 continue;
398                         }
399                         if (ret < 0)
400                                 break;
401
402                         leaf = path->nodes[0];
403                         fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
404                                             struct btrfs_file_extent_item);
405                         btrfs_set_file_extent_num_bytes(leaf, fi,
406                                                         start - key.offset);
407
408                         fi = btrfs_item_ptr(leaf, path->slots[0],
409                                             struct btrfs_file_extent_item);
410
411                         extent_offset += start - key.offset;
412                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
413                         btrfs_set_file_extent_num_bytes(leaf, fi,
414                                                         extent_end - start);
415                         btrfs_mark_buffer_dirty(leaf);
416
417                         if (disk_bytenr > 0) {
418                                 ret = btrfs_inc_extent_ref(trans, root,
419                                                 disk_bytenr, num_bytes, 0,
420                                                 root->root_key.objectid,
421                                                 new_key.objectid,
422                                                 start - extent_offset);
423                                 BUG_ON(ret);
424                                 *hint_byte = disk_bytenr;
425                         }
426                         key.offset = start;
427                 }
428                 /*
429                  *  | ---- range to drop ----- |
430                  *      | -------- extent -------- |
431                  */
432                 if (start <= key.offset && end < extent_end) {
433                         BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
434
435                         memcpy(&new_key, &key, sizeof(new_key));
436                         new_key.offset = end;
437                         btrfs_set_item_key_safe(trans, root, path, &new_key);
438
439                         extent_offset += end - key.offset;
440                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
441                         btrfs_set_file_extent_num_bytes(leaf, fi,
442                                                         extent_end - end);
443                         btrfs_mark_buffer_dirty(leaf);
444                         if (disk_bytenr > 0) {
445                                 inode_sub_bytes(inode, end - key.offset);
446                                 *hint_byte = disk_bytenr;
447                         }
448                         break;
449                 }
450
451                 search_start = extent_end;
452                 /*
453                  *       | ---- range to drop ----- |
454                  *  | -------- extent -------- |
455                  */
456                 if (start > key.offset && end >= extent_end) {
457                         BUG_ON(del_nr > 0);
458                         BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
459
460                         btrfs_set_file_extent_num_bytes(leaf, fi,
461                                                         start - key.offset);
462                         btrfs_mark_buffer_dirty(leaf);
463                         if (disk_bytenr > 0) {
464                                 inode_sub_bytes(inode, extent_end - start);
465                                 *hint_byte = disk_bytenr;
466                         }
467                         if (end == extent_end)
468                                 break;
469
470                         path->slots[0]++;
471                         goto next_slot;
472                 }
473
474                 /*
475                  *  | ---- range to drop ----- |
476                  *    | ------ extent ------ |
477                  */
478                 if (start <= key.offset && end >= extent_end) {
479                         if (del_nr == 0) {
480                                 del_slot = path->slots[0];
481                                 del_nr = 1;
482                         } else {
483                                 BUG_ON(del_slot + del_nr != path->slots[0]);
484                                 del_nr++;
485                         }
486
487                         if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
488                                 inode_sub_bytes(inode,
489                                                 extent_end - key.offset);
490                                 extent_end = ALIGN(extent_end,
491                                                    root->sectorsize);
492                         } else if (disk_bytenr > 0) {
493                                 ret = btrfs_free_extent(trans, root,
494                                                 disk_bytenr, num_bytes, 0,
495                                                 root->root_key.objectid,
496                                                 key.objectid, key.offset -
497                                                 extent_offset);
498                                 BUG_ON(ret);
499                                 inode_sub_bytes(inode,
500                                                 extent_end - key.offset);
501                                 *hint_byte = disk_bytenr;
502                         }
503
504                         if (end == extent_end)
505                                 break;
506
507                         if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
508                                 path->slots[0]++;
509                                 goto next_slot;
510                         }
511
512                         ret = btrfs_del_items(trans, root, path, del_slot,
513                                               del_nr);
514                         BUG_ON(ret);
515
516                         del_nr = 0;
517                         del_slot = 0;
518
519                         btrfs_release_path(root, path);
520                         continue;
521                 }
522
523                 BUG_ON(1);
524         }
525
526         if (del_nr > 0) {
527                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
528                 BUG_ON(ret);
529         }
530
531         btrfs_free_path(path);
532         return ret;
533 }
534
535 static int extent_mergeable(struct extent_buffer *leaf, int slot,
536                             u64 objectid, u64 bytenr, u64 orig_offset,
537                             u64 *start, u64 *end)
538 {
539         struct btrfs_file_extent_item *fi;
540         struct btrfs_key key;
541         u64 extent_end;
542
543         if (slot < 0 || slot >= btrfs_header_nritems(leaf))
544                 return 0;
545
546         btrfs_item_key_to_cpu(leaf, &key, slot);
547         if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
548                 return 0;
549
550         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
551         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
552             btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
553             btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
554             btrfs_file_extent_compression(leaf, fi) ||
555             btrfs_file_extent_encryption(leaf, fi) ||
556             btrfs_file_extent_other_encoding(leaf, fi))
557                 return 0;
558
559         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
560         if ((*start && *start != key.offset) || (*end && *end != extent_end))
561                 return 0;
562
563         *start = key.offset;
564         *end = extent_end;
565         return 1;
566 }
567
568 /*
569  * Mark extent in the range start - end as written.
570  *
571  * This changes extent type from 'pre-allocated' to 'regular'. If only
572  * part of extent is marked as written, the extent will be split into
573  * two or three.
574  */
575 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
576                               struct inode *inode, u64 start, u64 end)
577 {
578         struct btrfs_root *root = BTRFS_I(inode)->root;
579         struct extent_buffer *leaf;
580         struct btrfs_path *path;
581         struct btrfs_file_extent_item *fi;
582         struct btrfs_key key;
583         struct btrfs_key new_key;
584         u64 bytenr;
585         u64 num_bytes;
586         u64 extent_end;
587         u64 orig_offset;
588         u64 other_start;
589         u64 other_end;
590         u64 split;
591         int del_nr = 0;
592         int del_slot = 0;
593         int recow;
594         int ret;
595
596         btrfs_drop_extent_cache(inode, start, end - 1, 0);
597
598         path = btrfs_alloc_path();
599         BUG_ON(!path);
600 again:
601         recow = 0;
602         split = start;
603         key.objectid = inode->i_ino;
604         key.type = BTRFS_EXTENT_DATA_KEY;
605         key.offset = split;
606
607         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
608         if (ret < 0)
609                 goto out;
610         if (ret > 0 && path->slots[0] > 0)
611                 path->slots[0]--;
612
613         leaf = path->nodes[0];
614         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
615         BUG_ON(key.objectid != inode->i_ino ||
616                key.type != BTRFS_EXTENT_DATA_KEY);
617         fi = btrfs_item_ptr(leaf, path->slots[0],
618                             struct btrfs_file_extent_item);
619         BUG_ON(btrfs_file_extent_type(leaf, fi) !=
620                BTRFS_FILE_EXTENT_PREALLOC);
621         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
622         BUG_ON(key.offset > start || extent_end < end);
623
624         bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
625         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
626         orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
627         memcpy(&new_key, &key, sizeof(new_key));
628
629         if (start == key.offset && end < extent_end) {
630                 other_start = 0;
631                 other_end = start;
632                 if (extent_mergeable(leaf, path->slots[0] - 1,
633                                      inode->i_ino, bytenr, orig_offset,
634                                      &other_start, &other_end)) {
635                         new_key.offset = end;
636                         btrfs_set_item_key_safe(trans, root, path, &new_key);
637                         fi = btrfs_item_ptr(leaf, path->slots[0],
638                                             struct btrfs_file_extent_item);
639                         btrfs_set_file_extent_num_bytes(leaf, fi,
640                                                         extent_end - end);
641                         btrfs_set_file_extent_offset(leaf, fi,
642                                                      end - orig_offset);
643                         fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
644                                             struct btrfs_file_extent_item);
645                         btrfs_set_file_extent_num_bytes(leaf, fi,
646                                                         end - other_start);
647                         btrfs_mark_buffer_dirty(leaf);
648                         goto out;
649                 }
650         }
651
652         if (start > key.offset && end == extent_end) {
653                 other_start = end;
654                 other_end = 0;
655                 if (extent_mergeable(leaf, path->slots[0] + 1,
656                                      inode->i_ino, bytenr, orig_offset,
657                                      &other_start, &other_end)) {
658                         fi = btrfs_item_ptr(leaf, path->slots[0],
659                                             struct btrfs_file_extent_item);
660                         btrfs_set_file_extent_num_bytes(leaf, fi,
661                                                         start - key.offset);
662                         path->slots[0]++;
663                         new_key.offset = start;
664                         btrfs_set_item_key_safe(trans, root, path, &new_key);
665
666                         fi = btrfs_item_ptr(leaf, path->slots[0],
667                                             struct btrfs_file_extent_item);
668                         btrfs_set_file_extent_num_bytes(leaf, fi,
669                                                         other_end - start);
670                         btrfs_set_file_extent_offset(leaf, fi,
671                                                      start - orig_offset);
672                         btrfs_mark_buffer_dirty(leaf);
673                         goto out;
674                 }
675         }
676
677         while (start > key.offset || end < extent_end) {
678                 if (key.offset == start)
679                         split = end;
680
681                 new_key.offset = split;
682                 ret = btrfs_duplicate_item(trans, root, path, &new_key);
683                 if (ret == -EAGAIN) {
684                         btrfs_release_path(root, path);
685                         goto again;
686                 }
687                 BUG_ON(ret < 0);
688
689                 leaf = path->nodes[0];
690                 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
691                                     struct btrfs_file_extent_item);
692                 btrfs_set_file_extent_num_bytes(leaf, fi,
693                                                 split - key.offset);
694
695                 fi = btrfs_item_ptr(leaf, path->slots[0],
696                                     struct btrfs_file_extent_item);
697
698                 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
699                 btrfs_set_file_extent_num_bytes(leaf, fi,
700                                                 extent_end - split);
701                 btrfs_mark_buffer_dirty(leaf);
702
703                 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
704                                            root->root_key.objectid,
705                                            inode->i_ino, orig_offset);
706                 BUG_ON(ret);
707
708                 if (split == start) {
709                         key.offset = start;
710                 } else {
711                         BUG_ON(start != key.offset);
712                         path->slots[0]--;
713                         extent_end = end;
714                 }
715                 recow = 1;
716         }
717
718         other_start = end;
719         other_end = 0;
720         if (extent_mergeable(leaf, path->slots[0] + 1,
721                              inode->i_ino, bytenr, orig_offset,
722                              &other_start, &other_end)) {
723                 if (recow) {
724                         btrfs_release_path(root, path);
725                         goto again;
726                 }
727                 extent_end = other_end;
728                 del_slot = path->slots[0] + 1;
729                 del_nr++;
730                 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
731                                         0, root->root_key.objectid,
732                                         inode->i_ino, orig_offset);
733                 BUG_ON(ret);
734         }
735         other_start = 0;
736         other_end = start;
737         if (extent_mergeable(leaf, path->slots[0] - 1,
738                              inode->i_ino, bytenr, orig_offset,
739                              &other_start, &other_end)) {
740                 if (recow) {
741                         btrfs_release_path(root, path);
742                         goto again;
743                 }
744                 key.offset = other_start;
745                 del_slot = path->slots[0];
746                 del_nr++;
747                 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
748                                         0, root->root_key.objectid,
749                                         inode->i_ino, orig_offset);
750                 BUG_ON(ret);
751         }
752         if (del_nr == 0) {
753                 fi = btrfs_item_ptr(leaf, path->slots[0],
754                            struct btrfs_file_extent_item);
755                 btrfs_set_file_extent_type(leaf, fi,
756                                            BTRFS_FILE_EXTENT_REG);
757                 btrfs_mark_buffer_dirty(leaf);
758         } else {
759                 fi = btrfs_item_ptr(leaf, del_slot - 1,
760                            struct btrfs_file_extent_item);
761                 btrfs_set_file_extent_type(leaf, fi,
762                                            BTRFS_FILE_EXTENT_REG);
763                 btrfs_set_file_extent_num_bytes(leaf, fi,
764                                                 extent_end - key.offset);
765                 btrfs_mark_buffer_dirty(leaf);
766
767                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
768                 BUG_ON(ret);
769         }
770 out:
771         btrfs_free_path(path);
772         return 0;
773 }
774
775 /*
776  * on error we return an unlocked page and the error value
777  * on success we return a locked page and 0
778  */
779 static int prepare_uptodate_page(struct page *page, u64 pos)
780 {
781         int ret = 0;
782
783         if ((pos & (PAGE_CACHE_SIZE - 1)) && !PageUptodate(page)) {
784                 ret = btrfs_readpage(NULL, page);
785                 if (ret)
786                         return ret;
787                 lock_page(page);
788                 if (!PageUptodate(page)) {
789                         unlock_page(page);
790                         return -EIO;
791                 }
792         }
793         return 0;
794 }
795
796 /*
797  * this gets pages into the page cache and locks them down, it also properly
798  * waits for data=ordered extents to finish before allowing the pages to be
799  * modified.
800  */
801 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
802                          struct page **pages, size_t num_pages,
803                          loff_t pos, unsigned long first_index,
804                          unsigned long last_index, size_t write_bytes)
805 {
806         struct extent_state *cached_state = NULL;
807         int i;
808         unsigned long index = pos >> PAGE_CACHE_SHIFT;
809         struct inode *inode = fdentry(file)->d_inode;
810         int err = 0;
811         int faili = 0;
812         u64 start_pos;
813         u64 last_pos;
814
815         start_pos = pos & ~((u64)root->sectorsize - 1);
816         last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
817
818         if (start_pos > inode->i_size) {
819                 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
820                 if (err)
821                         return err;
822         }
823
824 again:
825         for (i = 0; i < num_pages; i++) {
826                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
827                 if (!pages[i]) {
828                         faili = i - 1;
829                         err = -ENOMEM;
830                         goto fail;
831                 }
832
833                 if (i == 0)
834                         err = prepare_uptodate_page(pages[i], pos);
835                 if (i == num_pages - 1)
836                         err = prepare_uptodate_page(pages[i],
837                                                     pos + write_bytes);
838                 if (err) {
839                         page_cache_release(pages[i]);
840                         faili = i - 1;
841                         goto fail;
842                 }
843                 wait_on_page_writeback(pages[i]);
844         }
845         err = 0;
846         if (start_pos < inode->i_size) {
847                 struct btrfs_ordered_extent *ordered;
848                 lock_extent_bits(&BTRFS_I(inode)->io_tree,
849                                  start_pos, last_pos - 1, 0, &cached_state,
850                                  GFP_NOFS);
851                 ordered = btrfs_lookup_first_ordered_extent(inode,
852                                                             last_pos - 1);
853                 if (ordered &&
854                     ordered->file_offset + ordered->len > start_pos &&
855                     ordered->file_offset < last_pos) {
856                         btrfs_put_ordered_extent(ordered);
857                         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
858                                              start_pos, last_pos - 1,
859                                              &cached_state, GFP_NOFS);
860                         for (i = 0; i < num_pages; i++) {
861                                 unlock_page(pages[i]);
862                                 page_cache_release(pages[i]);
863                         }
864                         btrfs_wait_ordered_range(inode, start_pos,
865                                                  last_pos - start_pos);
866                         goto again;
867                 }
868                 if (ordered)
869                         btrfs_put_ordered_extent(ordered);
870
871                 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
872                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
873                                   EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
874                                   GFP_NOFS);
875                 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
876                                      start_pos, last_pos - 1, &cached_state,
877                                      GFP_NOFS);
878         }
879         for (i = 0; i < num_pages; i++) {
880                 clear_page_dirty_for_io(pages[i]);
881                 set_page_extent_mapped(pages[i]);
882                 WARN_ON(!PageLocked(pages[i]));
883         }
884         return 0;
885 fail:
886         while (faili >= 0) {
887                 unlock_page(pages[faili]);
888                 page_cache_release(pages[faili]);
889                 faili--;
890         }
891         return err;
892
893 }
894
895 static noinline ssize_t __btrfs_buffered_write(struct file *file,
896                                                struct iov_iter *i,
897                                                loff_t pos)
898 {
899         struct inode *inode = fdentry(file)->d_inode;
900         struct btrfs_root *root = BTRFS_I(inode)->root;
901         struct page **pages = NULL;
902         unsigned long first_index;
903         unsigned long last_index;
904         size_t num_written = 0;
905         int nrptrs;
906         int ret = 0;
907
908         nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
909                      PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
910                      (sizeof(struct page *)));
911         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
912         if (!pages)
913                 return -ENOMEM;
914
915         first_index = pos >> PAGE_CACHE_SHIFT;
916         last_index = (pos + iov_iter_count(i)) >> PAGE_CACHE_SHIFT;
917
918         while (iov_iter_count(i) > 0) {
919                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
920                 size_t write_bytes = min(iov_iter_count(i),
921                                          nrptrs * (size_t)PAGE_CACHE_SIZE -
922                                          offset);
923                 size_t num_pages = (write_bytes + offset +
924                                     PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
925                 size_t dirty_pages;
926                 size_t copied;
927
928                 WARN_ON(num_pages > nrptrs);
929
930                 /*
931                  * Fault pages before locking them in prepare_pages
932                  * to avoid recursive lock
933                  */
934                 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
935                         ret = -EFAULT;
936                         break;
937                 }
938
939                 ret = btrfs_delalloc_reserve_space(inode,
940                                         num_pages << PAGE_CACHE_SHIFT);
941                 if (ret)
942                         break;
943
944                 /*
945                  * This is going to setup the pages array with the number of
946                  * pages we want, so we don't really need to worry about the
947                  * contents of pages from loop to loop
948                  */
949                 ret = prepare_pages(root, file, pages, num_pages,
950                                     pos, first_index, last_index,
951                                     write_bytes);
952                 if (ret) {
953                         btrfs_delalloc_release_space(inode,
954                                         num_pages << PAGE_CACHE_SHIFT);
955                         break;
956                 }
957
958                 copied = btrfs_copy_from_user(pos, num_pages,
959                                            write_bytes, pages, i);
960
961                 /*
962                  * if we have trouble faulting in the pages, fall
963                  * back to one page at a time
964                  */
965                 if (copied < write_bytes)
966                         nrptrs = 1;
967
968                 if (copied == 0)
969                         dirty_pages = 0;
970                 else
971                         dirty_pages = (copied + offset +
972                                        PAGE_CACHE_SIZE - 1) >>
973                                        PAGE_CACHE_SHIFT;
974
975                 /*
976                  * If we had a short copy we need to release the excess delaloc
977                  * bytes we reserved.  We need to increment outstanding_extents
978                  * because btrfs_delalloc_release_space will decrement it, but
979                  * we still have an outstanding extent for the chunk we actually
980                  * managed to copy.
981                  */
982                 if (num_pages > dirty_pages) {
983                         if (copied > 0)
984                                 atomic_inc(
985                                         &BTRFS_I(inode)->outstanding_extents);
986                         btrfs_delalloc_release_space(inode,
987                                         (num_pages - dirty_pages) <<
988                                         PAGE_CACHE_SHIFT);
989                 }
990
991                 if (copied > 0) {
992                         ret = btrfs_dirty_pages(root, inode, pages,
993                                                 dirty_pages, pos, copied,
994                                                 NULL);
995                         if (ret) {
996                                 btrfs_delalloc_release_space(inode,
997                                         dirty_pages << PAGE_CACHE_SHIFT);
998                                 btrfs_drop_pages(pages, num_pages);
999                                 break;
1000                         }
1001                 }
1002
1003                 btrfs_drop_pages(pages, num_pages);
1004
1005                 cond_resched();
1006
1007                 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1008                                                    dirty_pages);
1009                 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1010                         btrfs_btree_balance_dirty(root, 1);
1011                 btrfs_throttle(root);
1012
1013                 pos += copied;
1014                 num_written += copied;
1015         }
1016
1017         kfree(pages);
1018
1019         return num_written ? num_written : ret;
1020 }
1021
1022 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1023                                     const struct iovec *iov,
1024                                     unsigned long nr_segs, loff_t pos,
1025                                     loff_t *ppos, size_t count, size_t ocount)
1026 {
1027         struct file *file = iocb->ki_filp;
1028         struct inode *inode = fdentry(file)->d_inode;
1029         struct iov_iter i;
1030         ssize_t written;
1031         ssize_t written_buffered;
1032         loff_t endbyte;
1033         int err;
1034
1035         written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1036                                             count, ocount);
1037
1038         /*
1039          * the generic O_DIRECT will update in-memory i_size after the
1040          * DIOs are done.  But our endio handlers that update the on
1041          * disk i_size never update past the in memory i_size.  So we
1042          * need one more update here to catch any additions to the
1043          * file
1044          */
1045         if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
1046                 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
1047                 mark_inode_dirty(inode);
1048         }
1049
1050         if (written < 0 || written == count)
1051                 return written;
1052
1053         pos += written;
1054         count -= written;
1055         iov_iter_init(&i, iov, nr_segs, count, written);
1056         written_buffered = __btrfs_buffered_write(file, &i, pos);
1057         if (written_buffered < 0) {
1058                 err = written_buffered;
1059                 goto out;
1060         }
1061         endbyte = pos + written_buffered - 1;
1062         err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1063         if (err)
1064                 goto out;
1065         written += written_buffered;
1066         *ppos = pos + written_buffered;
1067         invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1068                                  endbyte >> PAGE_CACHE_SHIFT);
1069 out:
1070         return written ? written : err;
1071 }
1072
1073 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1074                                     const struct iovec *iov,
1075                                     unsigned long nr_segs, loff_t pos)
1076 {
1077         struct file *file = iocb->ki_filp;
1078         struct inode *inode = fdentry(file)->d_inode;
1079         struct btrfs_root *root = BTRFS_I(inode)->root;
1080         loff_t *ppos = &iocb->ki_pos;
1081         ssize_t num_written = 0;
1082         ssize_t err = 0;
1083         size_t count, ocount;
1084
1085         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1086
1087         mutex_lock(&inode->i_mutex);
1088
1089         err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1090         if (err) {
1091                 mutex_unlock(&inode->i_mutex);
1092                 goto out;
1093         }
1094         count = ocount;
1095
1096         current->backing_dev_info = inode->i_mapping->backing_dev_info;
1097         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1098         if (err) {
1099                 mutex_unlock(&inode->i_mutex);
1100                 goto out;
1101         }
1102
1103         if (count == 0) {
1104                 mutex_unlock(&inode->i_mutex);
1105                 goto out;
1106         }
1107
1108         err = file_remove_suid(file);
1109         if (err) {
1110                 mutex_unlock(&inode->i_mutex);
1111                 goto out;
1112         }
1113
1114         /*
1115          * If BTRFS flips readonly due to some impossible error
1116          * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1117          * although we have opened a file as writable, we have
1118          * to stop this write operation to ensure FS consistency.
1119          */
1120         if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
1121                 mutex_unlock(&inode->i_mutex);
1122                 err = -EROFS;
1123                 goto out;
1124         }
1125
1126         file_update_time(file);
1127         BTRFS_I(inode)->sequence++;
1128
1129         if (unlikely(file->f_flags & O_DIRECT)) {
1130                 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1131                                                    pos, ppos, count, ocount);
1132         } else {
1133                 struct iov_iter i;
1134
1135                 iov_iter_init(&i, iov, nr_segs, count, num_written);
1136
1137                 num_written = __btrfs_buffered_write(file, &i, pos);
1138                 if (num_written > 0)
1139                         *ppos = pos + num_written;
1140         }
1141
1142         mutex_unlock(&inode->i_mutex);
1143
1144         /*
1145          * we want to make sure fsync finds this change
1146          * but we haven't joined a transaction running right now.
1147          *
1148          * Later on, someone is sure to update the inode and get the
1149          * real transid recorded.
1150          *
1151          * We set last_trans now to the fs_info generation + 1,
1152          * this will either be one more than the running transaction
1153          * or the generation used for the next transaction if there isn't
1154          * one running right now.
1155          */
1156         BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1157         if (num_written > 0 || num_written == -EIOCBQUEUED) {
1158                 err = generic_write_sync(file, pos, num_written);
1159                 if (err < 0 && num_written > 0)
1160                         num_written = err;
1161         }
1162 out:
1163         current->backing_dev_info = NULL;
1164         return num_written ? num_written : err;
1165 }
1166
1167 int btrfs_release_file(struct inode *inode, struct file *filp)
1168 {
1169         /*
1170          * ordered_data_close is set by settattr when we are about to truncate
1171          * a file from a non-zero size to a zero size.  This tries to
1172          * flush down new bytes that may have been written if the
1173          * application were using truncate to replace a file in place.
1174          */
1175         if (BTRFS_I(inode)->ordered_data_close) {
1176                 BTRFS_I(inode)->ordered_data_close = 0;
1177                 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1178                 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1179                         filemap_flush(inode->i_mapping);
1180         }
1181         if (filp->private_data)
1182                 btrfs_ioctl_trans_end(filp);
1183         return 0;
1184 }
1185
1186 /*
1187  * fsync call for both files and directories.  This logs the inode into
1188  * the tree log instead of forcing full commits whenever possible.
1189  *
1190  * It needs to call filemap_fdatawait so that all ordered extent updates are
1191  * in the metadata btree are up to date for copying to the log.
1192  *
1193  * It drops the inode mutex before doing the tree log commit.  This is an
1194  * important optimization for directories because holding the mutex prevents
1195  * new operations on the dir while we write to disk.
1196  */
1197 int btrfs_sync_file(struct file *file, int datasync)
1198 {
1199         struct dentry *dentry = file->f_path.dentry;
1200         struct inode *inode = dentry->d_inode;
1201         struct btrfs_root *root = BTRFS_I(inode)->root;
1202         int ret = 0;
1203         struct btrfs_trans_handle *trans;
1204
1205         trace_btrfs_sync_file(file, datasync);
1206
1207         /* we wait first, since the writeback may change the inode */
1208         root->log_batch++;
1209         /* the VFS called filemap_fdatawrite for us */
1210         btrfs_wait_ordered_range(inode, 0, (u64)-1);
1211         root->log_batch++;
1212
1213         /*
1214          * check the transaction that last modified this inode
1215          * and see if its already been committed
1216          */
1217         if (!BTRFS_I(inode)->last_trans)
1218                 goto out;
1219
1220         /*
1221          * if the last transaction that changed this file was before
1222          * the current transaction, we can bail out now without any
1223          * syncing
1224          */
1225         mutex_lock(&root->fs_info->trans_mutex);
1226         if (BTRFS_I(inode)->last_trans <=
1227             root->fs_info->last_trans_committed) {
1228                 BTRFS_I(inode)->last_trans = 0;
1229                 mutex_unlock(&root->fs_info->trans_mutex);
1230                 goto out;
1231         }
1232         mutex_unlock(&root->fs_info->trans_mutex);
1233
1234         /*
1235          * ok we haven't committed the transaction yet, lets do a commit
1236          */
1237         if (file->private_data)
1238                 btrfs_ioctl_trans_end(file);
1239
1240         trans = btrfs_start_transaction(root, 0);
1241         if (IS_ERR(trans)) {
1242                 ret = PTR_ERR(trans);
1243                 goto out;
1244         }
1245
1246         ret = btrfs_log_dentry_safe(trans, root, dentry);
1247         if (ret < 0)
1248                 goto out;
1249
1250         /* we've logged all the items and now have a consistent
1251          * version of the file in the log.  It is possible that
1252          * someone will come in and modify the file, but that's
1253          * fine because the log is consistent on disk, and we
1254          * have references to all of the file's extents
1255          *
1256          * It is possible that someone will come in and log the
1257          * file again, but that will end up using the synchronization
1258          * inside btrfs_sync_log to keep things safe.
1259          */
1260         mutex_unlock(&dentry->d_inode->i_mutex);
1261
1262         if (ret != BTRFS_NO_LOG_SYNC) {
1263                 if (ret > 0) {
1264                         ret = btrfs_commit_transaction(trans, root);
1265                 } else {
1266                         ret = btrfs_sync_log(trans, root);
1267                         if (ret == 0)
1268                                 ret = btrfs_end_transaction(trans, root);
1269                         else
1270                                 ret = btrfs_commit_transaction(trans, root);
1271                 }
1272         } else {
1273                 ret = btrfs_end_transaction(trans, root);
1274         }
1275         mutex_lock(&dentry->d_inode->i_mutex);
1276 out:
1277         return ret > 0 ? -EIO : ret;
1278 }
1279
1280 static const struct vm_operations_struct btrfs_file_vm_ops = {
1281         .fault          = filemap_fault,
1282         .page_mkwrite   = btrfs_page_mkwrite,
1283 };
1284
1285 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1286 {
1287         struct address_space *mapping = filp->f_mapping;
1288
1289         if (!mapping->a_ops->readpage)
1290                 return -ENOEXEC;
1291
1292         file_accessed(filp);
1293         vma->vm_ops = &btrfs_file_vm_ops;
1294         vma->vm_flags |= VM_CAN_NONLINEAR;
1295
1296         return 0;
1297 }
1298
1299 static long btrfs_fallocate(struct file *file, int mode,
1300                             loff_t offset, loff_t len)
1301 {
1302         struct inode *inode = file->f_path.dentry->d_inode;
1303         struct extent_state *cached_state = NULL;
1304         u64 cur_offset;
1305         u64 last_byte;
1306         u64 alloc_start;
1307         u64 alloc_end;
1308         u64 alloc_hint = 0;
1309         u64 locked_end;
1310         u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1311         struct extent_map *em;
1312         int ret;
1313
1314         alloc_start = offset & ~mask;
1315         alloc_end =  (offset + len + mask) & ~mask;
1316
1317         /* We only support the FALLOC_FL_KEEP_SIZE mode */
1318         if (mode & ~FALLOC_FL_KEEP_SIZE)
1319                 return -EOPNOTSUPP;
1320
1321         /*
1322          * wait for ordered IO before we have any locks.  We'll loop again
1323          * below with the locks held.
1324          */
1325         btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1326
1327         mutex_lock(&inode->i_mutex);
1328         ret = inode_newsize_ok(inode, alloc_end);
1329         if (ret)
1330                 goto out;
1331
1332         if (alloc_start > inode->i_size) {
1333                 ret = btrfs_cont_expand(inode, i_size_read(inode),
1334                                         alloc_start);
1335                 if (ret)
1336                         goto out;
1337         }
1338
1339         ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
1340         if (ret)
1341                 goto out;
1342
1343         locked_end = alloc_end - 1;
1344         while (1) {
1345                 struct btrfs_ordered_extent *ordered;
1346
1347                 /* the extent lock is ordered inside the running
1348                  * transaction
1349                  */
1350                 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1351                                  locked_end, 0, &cached_state, GFP_NOFS);
1352                 ordered = btrfs_lookup_first_ordered_extent(inode,
1353                                                             alloc_end - 1);
1354                 if (ordered &&
1355                     ordered->file_offset + ordered->len > alloc_start &&
1356                     ordered->file_offset < alloc_end) {
1357                         btrfs_put_ordered_extent(ordered);
1358                         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1359                                              alloc_start, locked_end,
1360                                              &cached_state, GFP_NOFS);
1361                         /*
1362                          * we can't wait on the range with the transaction
1363                          * running or with the extent lock held
1364                          */
1365                         btrfs_wait_ordered_range(inode, alloc_start,
1366                                                  alloc_end - alloc_start);
1367                 } else {
1368                         if (ordered)
1369                                 btrfs_put_ordered_extent(ordered);
1370                         break;
1371                 }
1372         }
1373
1374         cur_offset = alloc_start;
1375         while (1) {
1376                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1377                                       alloc_end - cur_offset, 0);
1378                 BUG_ON(IS_ERR(em) || !em);
1379                 last_byte = min(extent_map_end(em), alloc_end);
1380                 last_byte = (last_byte + mask) & ~mask;
1381                 if (em->block_start == EXTENT_MAP_HOLE ||
1382                     (cur_offset >= inode->i_size &&
1383                      !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1384                         ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1385                                                         last_byte - cur_offset,
1386                                                         1 << inode->i_blkbits,
1387                                                         offset + len,
1388                                                         &alloc_hint);
1389                         if (ret < 0) {
1390                                 free_extent_map(em);
1391                                 break;
1392                         }
1393                 }
1394                 free_extent_map(em);
1395
1396                 cur_offset = last_byte;
1397                 if (cur_offset >= alloc_end) {
1398                         ret = 0;
1399                         break;
1400                 }
1401         }
1402         unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1403                              &cached_state, GFP_NOFS);
1404
1405         btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
1406 out:
1407         mutex_unlock(&inode->i_mutex);
1408         return ret;
1409 }
1410
1411 const struct file_operations btrfs_file_operations = {
1412         .llseek         = generic_file_llseek,
1413         .read           = do_sync_read,
1414         .write          = do_sync_write,
1415         .aio_read       = generic_file_aio_read,
1416         .splice_read    = generic_file_splice_read,
1417         .aio_write      = btrfs_file_aio_write,
1418         .mmap           = btrfs_file_mmap,
1419         .open           = generic_file_open,
1420         .release        = btrfs_release_file,
1421         .fsync          = btrfs_sync_file,
1422         .fallocate      = btrfs_fallocate,
1423         .unlocked_ioctl = btrfs_ioctl,
1424 #ifdef CONFIG_COMPAT
1425         .compat_ioctl   = btrfs_ioctl,
1426 #endif
1427 };