656bc0a892b14c6b6a420cda879e3b3e1fc9acf7
[linux-2.6.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 static noinline 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 static noinline int dirty_and_release_pages(struct btrfs_root *root,
131                                             struct file *file,
132                                             struct page **pages,
133                                             size_t num_pages,
134                                             loff_t pos,
135                                             size_t write_bytes)
136 {
137         int err = 0;
138         int i;
139         struct inode *inode = fdentry(file)->d_inode;
140         u64 num_bytes;
141         u64 start_pos;
142         u64 end_of_last_block;
143         u64 end_pos = pos + write_bytes;
144         loff_t isize = i_size_read(inode);
145
146         start_pos = pos & ~((u64)root->sectorsize - 1);
147         num_bytes = (write_bytes + pos - start_pos +
148                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
149
150         end_of_last_block = start_pos + num_bytes - 1;
151         err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
152                                         NULL);
153         if (err)
154                 return err;
155
156         for (i = 0; i < num_pages; i++) {
157                 struct page *p = pages[i];
158                 SetPageUptodate(p);
159                 ClearPageChecked(p);
160                 set_page_dirty(p);
161         }
162
163         /*
164          * we've only changed i_size in ram, and we haven't updated
165          * the disk i_size.  There is no need to log the inode
166          * at this time.
167          */
168         if (end_pos > isize)
169                 i_size_write(inode, end_pos);
170         return 0;
171 }
172
173 /*
174  * this drops all the extents in the cache that intersect the range
175  * [start, end].  Existing extents are split as required.
176  */
177 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
178                             int skip_pinned)
179 {
180         struct extent_map *em;
181         struct extent_map *split = NULL;
182         struct extent_map *split2 = NULL;
183         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
184         u64 len = end - start + 1;
185         int ret;
186         int testend = 1;
187         unsigned long flags;
188         int compressed = 0;
189
190         WARN_ON(end < start);
191         if (end == (u64)-1) {
192                 len = (u64)-1;
193                 testend = 0;
194         }
195         while (1) {
196                 if (!split)
197                         split = alloc_extent_map(GFP_NOFS);
198                 if (!split2)
199                         split2 = alloc_extent_map(GFP_NOFS);
200                 BUG_ON(!split || !split2);
201
202                 write_lock(&em_tree->lock);
203                 em = lookup_extent_mapping(em_tree, start, len);
204                 if (!em) {
205                         write_unlock(&em_tree->lock);
206                         break;
207                 }
208                 flags = em->flags;
209                 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
210                         if (testend && em->start + em->len >= start + len) {
211                                 free_extent_map(em);
212                                 write_unlock(&em_tree->lock);
213                                 break;
214                         }
215                         start = em->start + em->len;
216                         if (testend)
217                                 len = start + len - (em->start + em->len);
218                         free_extent_map(em);
219                         write_unlock(&em_tree->lock);
220                         continue;
221                 }
222                 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
223                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
224                 remove_extent_mapping(em_tree, em);
225
226                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
227                     em->start < start) {
228                         split->start = em->start;
229                         split->len = start - em->start;
230                         split->orig_start = em->orig_start;
231                         split->block_start = em->block_start;
232
233                         if (compressed)
234                                 split->block_len = em->block_len;
235                         else
236                                 split->block_len = split->len;
237
238                         split->bdev = em->bdev;
239                         split->flags = flags;
240                         split->compress_type = em->compress_type;
241                         ret = add_extent_mapping(em_tree, split);
242                         BUG_ON(ret);
243                         free_extent_map(split);
244                         split = split2;
245                         split2 = NULL;
246                 }
247                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
248                     testend && em->start + em->len > start + len) {
249                         u64 diff = start + len - em->start;
250
251                         split->start = start + len;
252                         split->len = em->start + em->len - (start + len);
253                         split->bdev = em->bdev;
254                         split->flags = flags;
255                         split->compress_type = em->compress_type;
256
257                         if (compressed) {
258                                 split->block_len = em->block_len;
259                                 split->block_start = em->block_start;
260                                 split->orig_start = em->orig_start;
261                         } else {
262                                 split->block_len = split->len;
263                                 split->block_start = em->block_start + diff;
264                                 split->orig_start = split->start;
265                         }
266
267                         ret = add_extent_mapping(em_tree, split);
268                         BUG_ON(ret);
269                         free_extent_map(split);
270                         split = NULL;
271                 }
272                 write_unlock(&em_tree->lock);
273
274                 /* once for us */
275                 free_extent_map(em);
276                 /* once for the tree*/
277                 free_extent_map(em);
278         }
279         if (split)
280                 free_extent_map(split);
281         if (split2)
282                 free_extent_map(split2);
283         return 0;
284 }
285
286 /*
287  * this is very complex, but the basic idea is to drop all extents
288  * in the range start - end.  hint_block is filled in with a block number
289  * that would be a good hint to the block allocator for this file.
290  *
291  * If an extent intersects the range but is not entirely inside the range
292  * it is either truncated or split.  Anything entirely inside the range
293  * is deleted from the tree.
294  */
295 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
296                        u64 start, u64 end, u64 *hint_byte, int drop_cache)
297 {
298         struct btrfs_root *root = BTRFS_I(inode)->root;
299         struct extent_buffer *leaf;
300         struct btrfs_file_extent_item *fi;
301         struct btrfs_path *path;
302         struct btrfs_key key;
303         struct btrfs_key new_key;
304         u64 search_start = start;
305         u64 disk_bytenr = 0;
306         u64 num_bytes = 0;
307         u64 extent_offset = 0;
308         u64 extent_end = 0;
309         int del_nr = 0;
310         int del_slot = 0;
311         int extent_type;
312         int recow;
313         int ret;
314
315         if (drop_cache)
316                 btrfs_drop_extent_cache(inode, start, end - 1, 0);
317
318         path = btrfs_alloc_path();
319         if (!path)
320                 return -ENOMEM;
321
322         while (1) {
323                 recow = 0;
324                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
325                                                search_start, -1);
326                 if (ret < 0)
327                         break;
328                 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
329                         leaf = path->nodes[0];
330                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
331                         if (key.objectid == inode->i_ino &&
332                             key.type == BTRFS_EXTENT_DATA_KEY)
333                                 path->slots[0]--;
334                 }
335                 ret = 0;
336 next_slot:
337                 leaf = path->nodes[0];
338                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
339                         BUG_ON(del_nr > 0);
340                         ret = btrfs_next_leaf(root, path);
341                         if (ret < 0)
342                                 break;
343                         if (ret > 0) {
344                                 ret = 0;
345                                 break;
346                         }
347                         leaf = path->nodes[0];
348                         recow = 1;
349                 }
350
351                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
352                 if (key.objectid > inode->i_ino ||
353                     key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
354                         break;
355
356                 fi = btrfs_item_ptr(leaf, path->slots[0],
357                                     struct btrfs_file_extent_item);
358                 extent_type = btrfs_file_extent_type(leaf, fi);
359
360                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
361                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
362                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
363                         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
364                         extent_offset = btrfs_file_extent_offset(leaf, fi);
365                         extent_end = key.offset +
366                                 btrfs_file_extent_num_bytes(leaf, fi);
367                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
368                         extent_end = key.offset +
369                                 btrfs_file_extent_inline_len(leaf, fi);
370                 } else {
371                         WARN_ON(1);
372                         extent_end = search_start;
373                 }
374
375                 if (extent_end <= search_start) {
376                         path->slots[0]++;
377                         goto next_slot;
378                 }
379
380                 search_start = max(key.offset, start);
381                 if (recow) {
382                         btrfs_release_path(root, path);
383                         continue;
384                 }
385
386                 /*
387                  *     | - range to drop - |
388                  *  | -------- extent -------- |
389                  */
390                 if (start > key.offset && end < extent_end) {
391                         BUG_ON(del_nr > 0);
392                         BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
393
394                         memcpy(&new_key, &key, sizeof(new_key));
395                         new_key.offset = start;
396                         ret = btrfs_duplicate_item(trans, root, path,
397                                                    &new_key);
398                         if (ret == -EAGAIN) {
399                                 btrfs_release_path(root, path);
400                                 continue;
401                         }
402                         if (ret < 0)
403                                 break;
404
405                         leaf = path->nodes[0];
406                         fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
407                                             struct btrfs_file_extent_item);
408                         btrfs_set_file_extent_num_bytes(leaf, fi,
409                                                         start - key.offset);
410
411                         fi = btrfs_item_ptr(leaf, path->slots[0],
412                                             struct btrfs_file_extent_item);
413
414                         extent_offset += start - key.offset;
415                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
416                         btrfs_set_file_extent_num_bytes(leaf, fi,
417                                                         extent_end - start);
418                         btrfs_mark_buffer_dirty(leaf);
419
420                         if (disk_bytenr > 0) {
421                                 ret = btrfs_inc_extent_ref(trans, root,
422                                                 disk_bytenr, num_bytes, 0,
423                                                 root->root_key.objectid,
424                                                 new_key.objectid,
425                                                 start - extent_offset);
426                                 BUG_ON(ret);
427                                 *hint_byte = disk_bytenr;
428                         }
429                         key.offset = start;
430                 }
431                 /*
432                  *  | ---- range to drop ----- |
433                  *      | -------- extent -------- |
434                  */
435                 if (start <= key.offset && end < extent_end) {
436                         BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
437
438                         memcpy(&new_key, &key, sizeof(new_key));
439                         new_key.offset = end;
440                         btrfs_set_item_key_safe(trans, root, path, &new_key);
441
442                         extent_offset += end - key.offset;
443                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
444                         btrfs_set_file_extent_num_bytes(leaf, fi,
445                                                         extent_end - end);
446                         btrfs_mark_buffer_dirty(leaf);
447                         if (disk_bytenr > 0) {
448                                 inode_sub_bytes(inode, end - key.offset);
449                                 *hint_byte = disk_bytenr;
450                         }
451                         break;
452                 }
453
454                 search_start = extent_end;
455                 /*
456                  *       | ---- range to drop ----- |
457                  *  | -------- extent -------- |
458                  */
459                 if (start > key.offset && end >= extent_end) {
460                         BUG_ON(del_nr > 0);
461                         BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
462
463                         btrfs_set_file_extent_num_bytes(leaf, fi,
464                                                         start - key.offset);
465                         btrfs_mark_buffer_dirty(leaf);
466                         if (disk_bytenr > 0) {
467                                 inode_sub_bytes(inode, extent_end - start);
468                                 *hint_byte = disk_bytenr;
469                         }
470                         if (end == extent_end)
471                                 break;
472
473                         path->slots[0]++;
474                         goto next_slot;
475                 }
476
477                 /*
478                  *  | ---- range to drop ----- |
479                  *    | ------ extent ------ |
480                  */
481                 if (start <= key.offset && end >= extent_end) {
482                         if (del_nr == 0) {
483                                 del_slot = path->slots[0];
484                                 del_nr = 1;
485                         } else {
486                                 BUG_ON(del_slot + del_nr != path->slots[0]);
487                                 del_nr++;
488                         }
489
490                         if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
491                                 inode_sub_bytes(inode,
492                                                 extent_end - key.offset);
493                                 extent_end = ALIGN(extent_end,
494                                                    root->sectorsize);
495                         } else if (disk_bytenr > 0) {
496                                 ret = btrfs_free_extent(trans, root,
497                                                 disk_bytenr, num_bytes, 0,
498                                                 root->root_key.objectid,
499                                                 key.objectid, key.offset -
500                                                 extent_offset);
501                                 BUG_ON(ret);
502                                 inode_sub_bytes(inode,
503                                                 extent_end - key.offset);
504                                 *hint_byte = disk_bytenr;
505                         }
506
507                         if (end == extent_end)
508                                 break;
509
510                         if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
511                                 path->slots[0]++;
512                                 goto next_slot;
513                         }
514
515                         ret = btrfs_del_items(trans, root, path, del_slot,
516                                               del_nr);
517                         BUG_ON(ret);
518
519                         del_nr = 0;
520                         del_slot = 0;
521
522                         btrfs_release_path(root, path);
523                         continue;
524                 }
525
526                 BUG_ON(1);
527         }
528
529         if (del_nr > 0) {
530                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
531                 BUG_ON(ret);
532         }
533
534         btrfs_free_path(path);
535         return ret;
536 }
537
538 static int extent_mergeable(struct extent_buffer *leaf, int slot,
539                             u64 objectid, u64 bytenr, u64 orig_offset,
540                             u64 *start, u64 *end)
541 {
542         struct btrfs_file_extent_item *fi;
543         struct btrfs_key key;
544         u64 extent_end;
545
546         if (slot < 0 || slot >= btrfs_header_nritems(leaf))
547                 return 0;
548
549         btrfs_item_key_to_cpu(leaf, &key, slot);
550         if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
551                 return 0;
552
553         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
554         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
555             btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
556             btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
557             btrfs_file_extent_compression(leaf, fi) ||
558             btrfs_file_extent_encryption(leaf, fi) ||
559             btrfs_file_extent_other_encoding(leaf, fi))
560                 return 0;
561
562         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
563         if ((*start && *start != key.offset) || (*end && *end != extent_end))
564                 return 0;
565
566         *start = key.offset;
567         *end = extent_end;
568         return 1;
569 }
570
571 /*
572  * Mark extent in the range start - end as written.
573  *
574  * This changes extent type from 'pre-allocated' to 'regular'. If only
575  * part of extent is marked as written, the extent will be split into
576  * two or three.
577  */
578 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
579                               struct inode *inode, u64 start, u64 end)
580 {
581         struct btrfs_root *root = BTRFS_I(inode)->root;
582         struct extent_buffer *leaf;
583         struct btrfs_path *path;
584         struct btrfs_file_extent_item *fi;
585         struct btrfs_key key;
586         struct btrfs_key new_key;
587         u64 bytenr;
588         u64 num_bytes;
589         u64 extent_end;
590         u64 orig_offset;
591         u64 other_start;
592         u64 other_end;
593         u64 split;
594         int del_nr = 0;
595         int del_slot = 0;
596         int recow;
597         int ret;
598
599         btrfs_drop_extent_cache(inode, start, end - 1, 0);
600
601         path = btrfs_alloc_path();
602         BUG_ON(!path);
603 again:
604         recow = 0;
605         split = start;
606         key.objectid = inode->i_ino;
607         key.type = BTRFS_EXTENT_DATA_KEY;
608         key.offset = split;
609
610         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
611         if (ret < 0)
612                 goto out;
613         if (ret > 0 && path->slots[0] > 0)
614                 path->slots[0]--;
615
616         leaf = path->nodes[0];
617         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
618         BUG_ON(key.objectid != inode->i_ino ||
619                key.type != BTRFS_EXTENT_DATA_KEY);
620         fi = btrfs_item_ptr(leaf, path->slots[0],
621                             struct btrfs_file_extent_item);
622         BUG_ON(btrfs_file_extent_type(leaf, fi) !=
623                BTRFS_FILE_EXTENT_PREALLOC);
624         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
625         BUG_ON(key.offset > start || extent_end < end);
626
627         bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
628         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
629         orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
630         memcpy(&new_key, &key, sizeof(new_key));
631
632         if (start == key.offset && end < extent_end) {
633                 other_start = 0;
634                 other_end = start;
635                 if (extent_mergeable(leaf, path->slots[0] - 1,
636                                      inode->i_ino, bytenr, orig_offset,
637                                      &other_start, &other_end)) {
638                         new_key.offset = end;
639                         btrfs_set_item_key_safe(trans, root, path, &new_key);
640                         fi = btrfs_item_ptr(leaf, path->slots[0],
641                                             struct btrfs_file_extent_item);
642                         btrfs_set_file_extent_num_bytes(leaf, fi,
643                                                         extent_end - end);
644                         btrfs_set_file_extent_offset(leaf, fi,
645                                                      end - orig_offset);
646                         fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
647                                             struct btrfs_file_extent_item);
648                         btrfs_set_file_extent_num_bytes(leaf, fi,
649                                                         end - other_start);
650                         btrfs_mark_buffer_dirty(leaf);
651                         goto out;
652                 }
653         }
654
655         if (start > key.offset && end == extent_end) {
656                 other_start = end;
657                 other_end = 0;
658                 if (extent_mergeable(leaf, path->slots[0] + 1,
659                                      inode->i_ino, bytenr, orig_offset,
660                                      &other_start, &other_end)) {
661                         fi = btrfs_item_ptr(leaf, path->slots[0],
662                                             struct btrfs_file_extent_item);
663                         btrfs_set_file_extent_num_bytes(leaf, fi,
664                                                         start - key.offset);
665                         path->slots[0]++;
666                         new_key.offset = start;
667                         btrfs_set_item_key_safe(trans, root, path, &new_key);
668
669                         fi = btrfs_item_ptr(leaf, path->slots[0],
670                                             struct btrfs_file_extent_item);
671                         btrfs_set_file_extent_num_bytes(leaf, fi,
672                                                         other_end - start);
673                         btrfs_set_file_extent_offset(leaf, fi,
674                                                      start - orig_offset);
675                         btrfs_mark_buffer_dirty(leaf);
676                         goto out;
677                 }
678         }
679
680         while (start > key.offset || end < extent_end) {
681                 if (key.offset == start)
682                         split = end;
683
684                 new_key.offset = split;
685                 ret = btrfs_duplicate_item(trans, root, path, &new_key);
686                 if (ret == -EAGAIN) {
687                         btrfs_release_path(root, path);
688                         goto again;
689                 }
690                 BUG_ON(ret < 0);
691
692                 leaf = path->nodes[0];
693                 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
694                                     struct btrfs_file_extent_item);
695                 btrfs_set_file_extent_num_bytes(leaf, fi,
696                                                 split - key.offset);
697
698                 fi = btrfs_item_ptr(leaf, path->slots[0],
699                                     struct btrfs_file_extent_item);
700
701                 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
702                 btrfs_set_file_extent_num_bytes(leaf, fi,
703                                                 extent_end - split);
704                 btrfs_mark_buffer_dirty(leaf);
705
706                 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
707                                            root->root_key.objectid,
708                                            inode->i_ino, orig_offset);
709                 BUG_ON(ret);
710
711                 if (split == start) {
712                         key.offset = start;
713                 } else {
714                         BUG_ON(start != key.offset);
715                         path->slots[0]--;
716                         extent_end = end;
717                 }
718                 recow = 1;
719         }
720
721         other_start = end;
722         other_end = 0;
723         if (extent_mergeable(leaf, path->slots[0] + 1,
724                              inode->i_ino, bytenr, orig_offset,
725                              &other_start, &other_end)) {
726                 if (recow) {
727                         btrfs_release_path(root, path);
728                         goto again;
729                 }
730                 extent_end = other_end;
731                 del_slot = path->slots[0] + 1;
732                 del_nr++;
733                 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
734                                         0, root->root_key.objectid,
735                                         inode->i_ino, orig_offset);
736                 BUG_ON(ret);
737         }
738         other_start = 0;
739         other_end = start;
740         if (extent_mergeable(leaf, path->slots[0] - 1,
741                              inode->i_ino, bytenr, orig_offset,
742                              &other_start, &other_end)) {
743                 if (recow) {
744                         btrfs_release_path(root, path);
745                         goto again;
746                 }
747                 key.offset = other_start;
748                 del_slot = path->slots[0];
749                 del_nr++;
750                 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
751                                         0, root->root_key.objectid,
752                                         inode->i_ino, orig_offset);
753                 BUG_ON(ret);
754         }
755         if (del_nr == 0) {
756                 fi = btrfs_item_ptr(leaf, path->slots[0],
757                            struct btrfs_file_extent_item);
758                 btrfs_set_file_extent_type(leaf, fi,
759                                            BTRFS_FILE_EXTENT_REG);
760                 btrfs_mark_buffer_dirty(leaf);
761         } else {
762                 fi = btrfs_item_ptr(leaf, del_slot - 1,
763                            struct btrfs_file_extent_item);
764                 btrfs_set_file_extent_type(leaf, fi,
765                                            BTRFS_FILE_EXTENT_REG);
766                 btrfs_set_file_extent_num_bytes(leaf, fi,
767                                                 extent_end - key.offset);
768                 btrfs_mark_buffer_dirty(leaf);
769
770                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
771                 BUG_ON(ret);
772         }
773 out:
774         btrfs_free_path(path);
775         return 0;
776 }
777
778 /*
779  * on error we return an unlocked page and the error value
780  * on success we return a locked page and 0
781  */
782 static int prepare_uptodate_page(struct page *page, u64 pos)
783 {
784         int ret = 0;
785
786         if ((pos & (PAGE_CACHE_SIZE - 1)) && !PageUptodate(page)) {
787                 ret = btrfs_readpage(NULL, page);
788                 if (ret)
789                         return ret;
790                 lock_page(page);
791                 if (!PageUptodate(page)) {
792                         unlock_page(page);
793                         return -EIO;
794                 }
795         }
796         return 0;
797 }
798
799 /*
800  * this gets pages into the page cache and locks them down, it also properly
801  * waits for data=ordered extents to finish before allowing the pages to be
802  * modified.
803  */
804 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
805                          struct page **pages, size_t num_pages,
806                          loff_t pos, unsigned long first_index,
807                          unsigned long last_index, size_t write_bytes)
808 {
809         struct extent_state *cached_state = NULL;
810         int i;
811         unsigned long index = pos >> PAGE_CACHE_SHIFT;
812         struct inode *inode = fdentry(file)->d_inode;
813         int err = 0;
814         int faili = 0;
815         u64 start_pos;
816         u64 last_pos;
817
818         start_pos = pos & ~((u64)root->sectorsize - 1);
819         last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
820
821         if (start_pos > inode->i_size) {
822                 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
823                 if (err)
824                         return err;
825         }
826
827 again:
828         for (i = 0; i < num_pages; i++) {
829                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
830                 if (!pages[i]) {
831                         faili = i - 1;
832                         err = -ENOMEM;
833                         goto fail;
834                 }
835
836                 if (i == 0)
837                         err = prepare_uptodate_page(pages[i], pos);
838                 if (i == num_pages - 1)
839                         err = prepare_uptodate_page(pages[i],
840                                                     pos + write_bytes);
841                 if (err) {
842                         page_cache_release(pages[i]);
843                         faili = i - 1;
844                         goto fail;
845                 }
846                 wait_on_page_writeback(pages[i]);
847         }
848         err = 0;
849         if (start_pos < inode->i_size) {
850                 struct btrfs_ordered_extent *ordered;
851                 lock_extent_bits(&BTRFS_I(inode)->io_tree,
852                                  start_pos, last_pos - 1, 0, &cached_state,
853                                  GFP_NOFS);
854                 ordered = btrfs_lookup_first_ordered_extent(inode,
855                                                             last_pos - 1);
856                 if (ordered &&
857                     ordered->file_offset + ordered->len > start_pos &&
858                     ordered->file_offset < last_pos) {
859                         btrfs_put_ordered_extent(ordered);
860                         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
861                                              start_pos, last_pos - 1,
862                                              &cached_state, GFP_NOFS);
863                         for (i = 0; i < num_pages; i++) {
864                                 unlock_page(pages[i]);
865                                 page_cache_release(pages[i]);
866                         }
867                         btrfs_wait_ordered_range(inode, start_pos,
868                                                  last_pos - start_pos);
869                         goto again;
870                 }
871                 if (ordered)
872                         btrfs_put_ordered_extent(ordered);
873
874                 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
875                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
876                                   EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
877                                   GFP_NOFS);
878                 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
879                                      start_pos, last_pos - 1, &cached_state,
880                                      GFP_NOFS);
881         }
882         for (i = 0; i < num_pages; i++) {
883                 clear_page_dirty_for_io(pages[i]);
884                 set_page_extent_mapped(pages[i]);
885                 WARN_ON(!PageLocked(pages[i]));
886         }
887         return 0;
888 fail:
889         while (faili >= 0) {
890                 unlock_page(pages[faili]);
891                 page_cache_release(pages[faili]);
892                 faili--;
893         }
894         return err;
895
896 }
897
898 static noinline ssize_t __btrfs_buffered_write(struct file *file,
899                                                struct iov_iter *i,
900                                                loff_t pos)
901 {
902         struct inode *inode = fdentry(file)->d_inode;
903         struct btrfs_root *root = BTRFS_I(inode)->root;
904         struct page **pages = NULL;
905         unsigned long first_index;
906         unsigned long last_index;
907         size_t num_written = 0;
908         int nrptrs;
909         int ret;
910
911         nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
912                      PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
913                      (sizeof(struct page *)));
914         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
915         if (!pages)
916                 return -ENOMEM;
917
918         first_index = pos >> PAGE_CACHE_SHIFT;
919         last_index = (pos + iov_iter_count(i)) >> PAGE_CACHE_SHIFT;
920
921         while (iov_iter_count(i) > 0) {
922                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
923                 size_t write_bytes = min(iov_iter_count(i),
924                                          nrptrs * (size_t)PAGE_CACHE_SIZE -
925                                          offset);
926                 size_t num_pages = (write_bytes + offset +
927                                     PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
928                 size_t dirty_pages;
929                 size_t copied;
930
931                 WARN_ON(num_pages > nrptrs);
932
933                 /*
934                  * Fault pages before locking them in prepare_pages
935                  * to avoid recursive lock
936                  */
937                 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
938                         ret = -EFAULT;
939                         break;
940                 }
941
942                 ret = btrfs_delalloc_reserve_space(inode,
943                                         num_pages << PAGE_CACHE_SHIFT);
944                 if (ret)
945                         break;
946
947                 /*
948                  * This is going to setup the pages array with the number of
949                  * pages we want, so we don't really need to worry about the
950                  * contents of pages from loop to loop
951                  */
952                 ret = prepare_pages(root, file, pages, num_pages,
953                                     pos, first_index, last_index,
954                                     write_bytes);
955                 if (ret) {
956                         btrfs_delalloc_release_space(inode,
957                                         num_pages << PAGE_CACHE_SHIFT);
958                         break;
959                 }
960
961                 copied = btrfs_copy_from_user(pos, num_pages,
962                                            write_bytes, pages, i);
963
964                 /*
965                  * if we have trouble faulting in the pages, fall
966                  * back to one page at a time
967                  */
968                 if (copied < write_bytes)
969                         nrptrs = 1;
970
971                 if (copied == 0)
972                         dirty_pages = 0;
973                 else
974                         dirty_pages = (copied + offset +
975                                        PAGE_CACHE_SIZE - 1) >>
976                                        PAGE_CACHE_SHIFT;
977
978                 /*
979                  * If we had a short copy we need to release the excess delaloc
980                  * bytes we reserved.  We need to increment outstanding_extents
981                  * because btrfs_delalloc_release_space will decrement it, but
982                  * we still have an outstanding extent for the chunk we actually
983                  * managed to copy.
984                  */
985                 if (num_pages > dirty_pages) {
986                         if (copied > 0)
987                                 atomic_inc(
988                                         &BTRFS_I(inode)->outstanding_extents);
989                         btrfs_delalloc_release_space(inode,
990                                         (num_pages - dirty_pages) <<
991                                         PAGE_CACHE_SHIFT);
992                 }
993
994                 if (copied > 0) {
995                         ret = dirty_and_release_pages(root, file, pages,
996                                                       dirty_pages, pos,
997                                                       copied);
998                         if (ret) {
999                                 btrfs_delalloc_release_space(inode,
1000                                         dirty_pages << PAGE_CACHE_SHIFT);
1001                                 btrfs_drop_pages(pages, num_pages);
1002                                 break;
1003                         }
1004                 }
1005
1006                 btrfs_drop_pages(pages, num_pages);
1007
1008                 cond_resched();
1009
1010                 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1011                                                    dirty_pages);
1012                 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1013                         btrfs_btree_balance_dirty(root, 1);
1014                 btrfs_throttle(root);
1015
1016                 pos += copied;
1017                 num_written += copied;
1018         }
1019
1020         kfree(pages);
1021
1022         return num_written ? num_written : ret;
1023 }
1024
1025 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1026                                     const struct iovec *iov,
1027                                     unsigned long nr_segs, loff_t pos,
1028                                     loff_t *ppos, size_t count, size_t ocount)
1029 {
1030         struct file *file = iocb->ki_filp;
1031         struct inode *inode = fdentry(file)->d_inode;
1032         struct iov_iter i;
1033         ssize_t written;
1034         ssize_t written_buffered;
1035         loff_t endbyte;
1036         int err;
1037
1038         written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1039                                             count, ocount);
1040
1041         /*
1042          * the generic O_DIRECT will update in-memory i_size after the
1043          * DIOs are done.  But our endio handlers that update the on
1044          * disk i_size never update past the in memory i_size.  So we
1045          * need one more update here to catch any additions to the
1046          * file
1047          */
1048         if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
1049                 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
1050                 mark_inode_dirty(inode);
1051         }
1052
1053         if (written < 0 || written == count)
1054                 return written;
1055
1056         pos += written;
1057         count -= written;
1058         iov_iter_init(&i, iov, nr_segs, count, written);
1059         written_buffered = __btrfs_buffered_write(file, &i, pos);
1060         if (written_buffered < 0) {
1061                 err = written_buffered;
1062                 goto out;
1063         }
1064         endbyte = pos + written_buffered - 1;
1065         err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1066         if (err)
1067                 goto out;
1068         written += written_buffered;
1069         *ppos = pos + written_buffered;
1070         invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1071                                  endbyte >> PAGE_CACHE_SHIFT);
1072 out:
1073         return written ? written : err;
1074 }
1075
1076 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1077                                     const struct iovec *iov,
1078                                     unsigned long nr_segs, loff_t pos)
1079 {
1080         struct file *file = iocb->ki_filp;
1081         struct inode *inode = fdentry(file)->d_inode;
1082         struct btrfs_root *root = BTRFS_I(inode)->root;
1083         loff_t *ppos = &iocb->ki_pos;
1084         ssize_t num_written = 0;
1085         ssize_t err = 0;
1086         size_t count, ocount;
1087
1088         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1089
1090         mutex_lock(&inode->i_mutex);
1091
1092         err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1093         if (err) {
1094                 mutex_unlock(&inode->i_mutex);
1095                 goto out;
1096         }
1097         count = ocount;
1098
1099         current->backing_dev_info = inode->i_mapping->backing_dev_info;
1100         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1101         if (err) {
1102                 mutex_unlock(&inode->i_mutex);
1103                 goto out;
1104         }
1105
1106         if (count == 0) {
1107                 mutex_unlock(&inode->i_mutex);
1108                 goto out;
1109         }
1110
1111         err = file_remove_suid(file);
1112         if (err) {
1113                 mutex_unlock(&inode->i_mutex);
1114                 goto out;
1115         }
1116
1117         /*
1118          * If BTRFS flips readonly due to some impossible error
1119          * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1120          * although we have opened a file as writable, we have
1121          * to stop this write operation to ensure FS consistency.
1122          */
1123         if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
1124                 mutex_unlock(&inode->i_mutex);
1125                 err = -EROFS;
1126                 goto out;
1127         }
1128
1129         file_update_time(file);
1130         BTRFS_I(inode)->sequence++;
1131
1132         if (unlikely(file->f_flags & O_DIRECT)) {
1133                 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1134                                                    pos, ppos, count, ocount);
1135         } else {
1136                 struct iov_iter i;
1137
1138                 iov_iter_init(&i, iov, nr_segs, count, num_written);
1139
1140                 num_written = __btrfs_buffered_write(file, &i, pos);
1141                 if (num_written > 0)
1142                         *ppos = pos + num_written;
1143         }
1144
1145         mutex_unlock(&inode->i_mutex);
1146
1147         /*
1148          * we want to make sure fsync finds this change
1149          * but we haven't joined a transaction running right now.
1150          *
1151          * Later on, someone is sure to update the inode and get the
1152          * real transid recorded.
1153          *
1154          * We set last_trans now to the fs_info generation + 1,
1155          * this will either be one more than the running transaction
1156          * or the generation used for the next transaction if there isn't
1157          * one running right now.
1158          */
1159         BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1160         if (num_written > 0 || num_written == -EIOCBQUEUED) {
1161                 err = generic_write_sync(file, pos, num_written);
1162                 if (err < 0 && num_written > 0)
1163                         num_written = err;
1164         }
1165 out:
1166         current->backing_dev_info = NULL;
1167         return num_written ? num_written : err;
1168 }
1169
1170 int btrfs_release_file(struct inode *inode, struct file *filp)
1171 {
1172         /*
1173          * ordered_data_close is set by settattr when we are about to truncate
1174          * a file from a non-zero size to a zero size.  This tries to
1175          * flush down new bytes that may have been written if the
1176          * application were using truncate to replace a file in place.
1177          */
1178         if (BTRFS_I(inode)->ordered_data_close) {
1179                 BTRFS_I(inode)->ordered_data_close = 0;
1180                 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1181                 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1182                         filemap_flush(inode->i_mapping);
1183         }
1184         if (filp->private_data)
1185                 btrfs_ioctl_trans_end(filp);
1186         return 0;
1187 }
1188
1189 /*
1190  * fsync call for both files and directories.  This logs the inode into
1191  * the tree log instead of forcing full commits whenever possible.
1192  *
1193  * It needs to call filemap_fdatawait so that all ordered extent updates are
1194  * in the metadata btree are up to date for copying to the log.
1195  *
1196  * It drops the inode mutex before doing the tree log commit.  This is an
1197  * important optimization for directories because holding the mutex prevents
1198  * new operations on the dir while we write to disk.
1199  */
1200 int btrfs_sync_file(struct file *file, int datasync)
1201 {
1202         struct dentry *dentry = file->f_path.dentry;
1203         struct inode *inode = dentry->d_inode;
1204         struct btrfs_root *root = BTRFS_I(inode)->root;
1205         int ret = 0;
1206         struct btrfs_trans_handle *trans;
1207
1208         trace_btrfs_sync_file(file, datasync);
1209
1210         /* we wait first, since the writeback may change the inode */
1211         root->log_batch++;
1212         /* the VFS called filemap_fdatawrite for us */
1213         btrfs_wait_ordered_range(inode, 0, (u64)-1);
1214         root->log_batch++;
1215
1216         /*
1217          * check the transaction that last modified this inode
1218          * and see if its already been committed
1219          */
1220         if (!BTRFS_I(inode)->last_trans)
1221                 goto out;
1222
1223         /*
1224          * if the last transaction that changed this file was before
1225          * the current transaction, we can bail out now without any
1226          * syncing
1227          */
1228         mutex_lock(&root->fs_info->trans_mutex);
1229         if (BTRFS_I(inode)->last_trans <=
1230             root->fs_info->last_trans_committed) {
1231                 BTRFS_I(inode)->last_trans = 0;
1232                 mutex_unlock(&root->fs_info->trans_mutex);
1233                 goto out;
1234         }
1235         mutex_unlock(&root->fs_info->trans_mutex);
1236
1237         /*
1238          * ok we haven't committed the transaction yet, lets do a commit
1239          */
1240         if (file->private_data)
1241                 btrfs_ioctl_trans_end(file);
1242
1243         trans = btrfs_start_transaction(root, 0);
1244         if (IS_ERR(trans)) {
1245                 ret = PTR_ERR(trans);
1246                 goto out;
1247         }
1248
1249         ret = btrfs_log_dentry_safe(trans, root, dentry);
1250         if (ret < 0)
1251                 goto out;
1252
1253         /* we've logged all the items and now have a consistent
1254          * version of the file in the log.  It is possible that
1255          * someone will come in and modify the file, but that's
1256          * fine because the log is consistent on disk, and we
1257          * have references to all of the file's extents
1258          *
1259          * It is possible that someone will come in and log the
1260          * file again, but that will end up using the synchronization
1261          * inside btrfs_sync_log to keep things safe.
1262          */
1263         mutex_unlock(&dentry->d_inode->i_mutex);
1264
1265         if (ret != BTRFS_NO_LOG_SYNC) {
1266                 if (ret > 0) {
1267                         ret = btrfs_commit_transaction(trans, root);
1268                 } else {
1269                         ret = btrfs_sync_log(trans, root);
1270                         if (ret == 0)
1271                                 ret = btrfs_end_transaction(trans, root);
1272                         else
1273                                 ret = btrfs_commit_transaction(trans, root);
1274                 }
1275         } else {
1276                 ret = btrfs_end_transaction(trans, root);
1277         }
1278         mutex_lock(&dentry->d_inode->i_mutex);
1279 out:
1280         return ret > 0 ? -EIO : ret;
1281 }
1282
1283 static const struct vm_operations_struct btrfs_file_vm_ops = {
1284         .fault          = filemap_fault,
1285         .page_mkwrite   = btrfs_page_mkwrite,
1286 };
1287
1288 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1289 {
1290         struct address_space *mapping = filp->f_mapping;
1291
1292         if (!mapping->a_ops->readpage)
1293                 return -ENOEXEC;
1294
1295         file_accessed(filp);
1296         vma->vm_ops = &btrfs_file_vm_ops;
1297         vma->vm_flags |= VM_CAN_NONLINEAR;
1298
1299         return 0;
1300 }
1301
1302 static long btrfs_fallocate(struct file *file, int mode,
1303                             loff_t offset, loff_t len)
1304 {
1305         struct inode *inode = file->f_path.dentry->d_inode;
1306         struct extent_state *cached_state = NULL;
1307         u64 cur_offset;
1308         u64 last_byte;
1309         u64 alloc_start;
1310         u64 alloc_end;
1311         u64 alloc_hint = 0;
1312         u64 locked_end;
1313         u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1314         struct extent_map *em;
1315         int ret;
1316
1317         alloc_start = offset & ~mask;
1318         alloc_end =  (offset + len + mask) & ~mask;
1319
1320         /* We only support the FALLOC_FL_KEEP_SIZE mode */
1321         if (mode & ~FALLOC_FL_KEEP_SIZE)
1322                 return -EOPNOTSUPP;
1323
1324         /*
1325          * wait for ordered IO before we have any locks.  We'll loop again
1326          * below with the locks held.
1327          */
1328         btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1329
1330         mutex_lock(&inode->i_mutex);
1331         ret = inode_newsize_ok(inode, alloc_end);
1332         if (ret)
1333                 goto out;
1334
1335         if (alloc_start > inode->i_size) {
1336                 ret = btrfs_cont_expand(inode, i_size_read(inode),
1337                                         alloc_start);
1338                 if (ret)
1339                         goto out;
1340         }
1341
1342         ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
1343         if (ret)
1344                 goto out;
1345
1346         locked_end = alloc_end - 1;
1347         while (1) {
1348                 struct btrfs_ordered_extent *ordered;
1349
1350                 /* the extent lock is ordered inside the running
1351                  * transaction
1352                  */
1353                 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1354                                  locked_end, 0, &cached_state, GFP_NOFS);
1355                 ordered = btrfs_lookup_first_ordered_extent(inode,
1356                                                             alloc_end - 1);
1357                 if (ordered &&
1358                     ordered->file_offset + ordered->len > alloc_start &&
1359                     ordered->file_offset < alloc_end) {
1360                         btrfs_put_ordered_extent(ordered);
1361                         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1362                                              alloc_start, locked_end,
1363                                              &cached_state, GFP_NOFS);
1364                         /*
1365                          * we can't wait on the range with the transaction
1366                          * running or with the extent lock held
1367                          */
1368                         btrfs_wait_ordered_range(inode, alloc_start,
1369                                                  alloc_end - alloc_start);
1370                 } else {
1371                         if (ordered)
1372                                 btrfs_put_ordered_extent(ordered);
1373                         break;
1374                 }
1375         }
1376
1377         cur_offset = alloc_start;
1378         while (1) {
1379                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1380                                       alloc_end - cur_offset, 0);
1381                 BUG_ON(IS_ERR(em) || !em);
1382                 last_byte = min(extent_map_end(em), alloc_end);
1383                 last_byte = (last_byte + mask) & ~mask;
1384                 if (em->block_start == EXTENT_MAP_HOLE ||
1385                     (cur_offset >= inode->i_size &&
1386                      !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1387                         ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1388                                                         last_byte - cur_offset,
1389                                                         1 << inode->i_blkbits,
1390                                                         offset + len,
1391                                                         &alloc_hint);
1392                         if (ret < 0) {
1393                                 free_extent_map(em);
1394                                 break;
1395                         }
1396                 }
1397                 free_extent_map(em);
1398
1399                 cur_offset = last_byte;
1400                 if (cur_offset >= alloc_end) {
1401                         ret = 0;
1402                         break;
1403                 }
1404         }
1405         unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1406                              &cached_state, GFP_NOFS);
1407
1408         btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
1409 out:
1410         mutex_unlock(&inode->i_mutex);
1411         return ret;
1412 }
1413
1414 const struct file_operations btrfs_file_operations = {
1415         .llseek         = generic_file_llseek,
1416         .read           = do_sync_read,
1417         .write          = do_sync_write,
1418         .aio_read       = generic_file_aio_read,
1419         .splice_read    = generic_file_splice_read,
1420         .aio_write      = btrfs_file_aio_write,
1421         .mmap           = btrfs_file_mmap,
1422         .open           = generic_file_open,
1423         .release        = btrfs_release_file,
1424         .fsync          = btrfs_sync_file,
1425         .fallocate      = btrfs_fallocate,
1426         .unlocked_ioctl = btrfs_ioctl,
1427 #ifdef CONFIG_COMPAT
1428         .compat_ioctl   = btrfs_ioctl,
1429 #endif
1430 };