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Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[wandboard.git] / fs / btrfs / file.c
blob7084140d5940e68f653ad8919a0084549d6b8e1b
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 int write_bytes,
49 struct page **prepared_pages,
50 struct iov_iter *i)
51 {
52 size_t copied = 0;
53 int pg = 0;
54 int offset = pos & (PAGE_CACHE_SIZE - 1);
55 int total_copied = 0;
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 iov_iter_advance(i, copied);
74 write_bytes -= copied;
75 total_copied += copied;
76
77 /* Return to btrfs_file_aio_write to fault page */
78 if (unlikely(copied == 0)) {
79 break;
80 }
81
82 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
83 offset += copied;
84 } else {
85 pg++;
86 offset = 0;
87 }
88 }
89 return total_copied;
90 }
91
92 /*
93 * unlocks pages after btrfs_file_write is done with them
94 */
95 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
96 {
97 size_t i;
98 for (i = 0; i < num_pages; i++) {
99 if (!pages[i])
100 break;
101 /* page checked is some magic around finding pages that
102 * have been modified without going through btrfs_set_page_dirty
103 * clear it here
104 */
105 ClearPageChecked(pages[i]);
106 unlock_page(pages[i]);
107 mark_page_accessed(pages[i]);
108 page_cache_release(pages[i]);
109 }
110 }
111
112 /*
113 * after copy_from_user, pages need to be dirtied and we need to make
114 * sure holes are created between the current EOF and the start of
115 * any next extents (if required).
116 *
117 * this also makes the decision about creating an inline extent vs
118 * doing real data extents, marking pages dirty and delalloc as required.
119 */
120 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
121 struct btrfs_root *root,
122 struct file *file,
123 struct page **pages,
124 size_t num_pages,
125 loff_t pos,
126 size_t write_bytes)
127 {
128 int err = 0;
129 int i;
130 struct inode *inode = fdentry(file)->d_inode;
131 u64 num_bytes;
132 u64 start_pos;
133 u64 end_of_last_block;
134 u64 end_pos = pos + write_bytes;
135 loff_t isize = i_size_read(inode);
136
137 start_pos = pos & ~((u64)root->sectorsize - 1);
138 num_bytes = (write_bytes + pos - start_pos +
139 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
140
141 end_of_last_block = start_pos + num_bytes - 1;
142 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
143 NULL);
144 BUG_ON(err);
145
146 for (i = 0; i < num_pages; i++) {
147 struct page *p = pages[i];
148 SetPageUptodate(p);
149 ClearPageChecked(p);
150 set_page_dirty(p);
151 }
152 if (end_pos > isize) {
153 i_size_write(inode, end_pos);
154 /* we've only changed i_size in ram, and we haven't updated
155 * the disk i_size. There is no need to log the inode
156 * at this time.
157 */
158 }
159 return 0;
160 }
161
162 /*
163 * this drops all the extents in the cache that intersect the range
164 * [start, end]. Existing extents are split as required.
165 */
166 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
167 int skip_pinned)
168 {
169 struct extent_map *em;
170 struct extent_map *split = NULL;
171 struct extent_map *split2 = NULL;
172 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
173 u64 len = end - start + 1;
174 int ret;
175 int testend = 1;
176 unsigned long flags;
177 int compressed = 0;
178
179 WARN_ON(end < start);
180 if (end == (u64)-1) {
181 len = (u64)-1;
182 testend = 0;
183 }
184 while (1) {
185 if (!split)
186 split = alloc_extent_map(GFP_NOFS);
187 if (!split2)
188 split2 = alloc_extent_map(GFP_NOFS);
189 BUG_ON(!split || !split2);
190
191 write_lock(&em_tree->lock);
192 em = lookup_extent_mapping(em_tree, start, len);
193 if (!em) {
194 write_unlock(&em_tree->lock);
195 break;
196 }
197 flags = em->flags;
198 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
199 if (testend && em->start + em->len >= start + len) {
200 free_extent_map(em);
201 write_unlock(&em_tree->lock);
202 break;
203 }
204 start = em->start + em->len;
205 if (testend)
206 len = start + len - (em->start + em->len);
207 free_extent_map(em);
208 write_unlock(&em_tree->lock);
209 continue;
210 }
211 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
212 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
213 remove_extent_mapping(em_tree, em);
214
215 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
216 em->start < start) {
217 split->start = em->start;
218 split->len = start - em->start;
219 split->orig_start = em->orig_start;
220 split->block_start = em->block_start;
221
222 if (compressed)
223 split->block_len = em->block_len;
224 else
225 split->block_len = split->len;
226
227 split->bdev = em->bdev;
228 split->flags = flags;
229 split->compress_type = em->compress_type;
230 ret = add_extent_mapping(em_tree, split);
231 BUG_ON(ret);
232 free_extent_map(split);
233 split = split2;
234 split2 = NULL;
235 }
236 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
237 testend && em->start + em->len > start + len) {
238 u64 diff = start + len - em->start;
239
240 split->start = start + len;
241 split->len = em->start + em->len - (start + len);
242 split->bdev = em->bdev;
243 split->flags = flags;
244 split->compress_type = em->compress_type;
245
246 if (compressed) {
247 split->block_len = em->block_len;
248 split->block_start = em->block_start;
249 split->orig_start = em->orig_start;
250 } else {
251 split->block_len = split->len;
252 split->block_start = em->block_start + diff;
253 split->orig_start = split->start;
254 }
255
256 ret = add_extent_mapping(em_tree, split);
257 BUG_ON(ret);
258 free_extent_map(split);
259 split = NULL;
260 }
261 write_unlock(&em_tree->lock);
262
263 /* once for us */
264 free_extent_map(em);
265 /* once for the tree*/
266 free_extent_map(em);
267 }
268 if (split)
269 free_extent_map(split);
270 if (split2)
271 free_extent_map(split2);
272 return 0;
273 }
274
275 /*
276 * this is very complex, but the basic idea is to drop all extents
277 * in the range start - end. hint_block is filled in with a block number
278 * that would be a good hint to the block allocator for this file.
279 *
280 * If an extent intersects the range but is not entirely inside the range
281 * it is either truncated or split. Anything entirely inside the range
282 * is deleted from the tree.
283 */
284 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
285 u64 start, u64 end, u64 *hint_byte, int drop_cache)
286 {
287 struct btrfs_root *root = BTRFS_I(inode)->root;
288 struct extent_buffer *leaf;
289 struct btrfs_file_extent_item *fi;
290 struct btrfs_path *path;
291 struct btrfs_key key;
292 struct btrfs_key new_key;
293 u64 search_start = start;
294 u64 disk_bytenr = 0;
295 u64 num_bytes = 0;
296 u64 extent_offset = 0;
297 u64 extent_end = 0;
298 int del_nr = 0;
299 int del_slot = 0;
300 int extent_type;
301 int recow;
302 int ret;
303
304 if (drop_cache)
305 btrfs_drop_extent_cache(inode, start, end - 1, 0);
306
307 path = btrfs_alloc_path();
308 if (!path)
309 return -ENOMEM;
310
311 while (1) {
312 recow = 0;
313 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
314 search_start, -1);
315 if (ret < 0)
316 break;
317 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
318 leaf = path->nodes[0];
319 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
320 if (key.objectid == inode->i_ino &&
321 key.type == BTRFS_EXTENT_DATA_KEY)
322 path->slots[0]--;
323 }
324 ret = 0;
325 next_slot:
326 leaf = path->nodes[0];
327 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
328 BUG_ON(del_nr > 0);
329 ret = btrfs_next_leaf(root, path);
330 if (ret < 0)
331 break;
332 if (ret > 0) {
333 ret = 0;
334 break;
335 }
336 leaf = path->nodes[0];
337 recow = 1;
338 }
339
340 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
341 if (key.objectid > inode->i_ino ||
342 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
343 break;
344
345 fi = btrfs_item_ptr(leaf, path->slots[0],
346 struct btrfs_file_extent_item);
347 extent_type = btrfs_file_extent_type(leaf, fi);
348
349 if (extent_type == BTRFS_FILE_EXTENT_REG ||
350 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
351 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
352 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
353 extent_offset = btrfs_file_extent_offset(leaf, fi);
354 extent_end = key.offset +
355 btrfs_file_extent_num_bytes(leaf, fi);
356 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
357 extent_end = key.offset +
358 btrfs_file_extent_inline_len(leaf, fi);
359 } else {
360 WARN_ON(1);
361 extent_end = search_start;
362 }
363
364 if (extent_end <= search_start) {
365 path->slots[0]++;
366 goto next_slot;
367 }
368
369 search_start = max(key.offset, start);
370 if (recow) {
371 btrfs_release_path(root, path);
372 continue;
373 }
374
375 /*
376 * | - range to drop - |
377 * | -------- extent -------- |
378 */
379 if (start > key.offset && end < extent_end) {
380 BUG_ON(del_nr > 0);
381 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
382
383 memcpy(&new_key, &key, sizeof(new_key));
384 new_key.offset = start;
385 ret = btrfs_duplicate_item(trans, root, path,
386 &new_key);
387 if (ret == -EAGAIN) {
388 btrfs_release_path(root, path);
389 continue;
390 }
391 if (ret < 0)
392 break;
393
394 leaf = path->nodes[0];
395 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
396 struct btrfs_file_extent_item);
397 btrfs_set_file_extent_num_bytes(leaf, fi,
398 start - key.offset);
399
400 fi = btrfs_item_ptr(leaf, path->slots[0],
401 struct btrfs_file_extent_item);
402
403 extent_offset += start - key.offset;
404 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
405 btrfs_set_file_extent_num_bytes(leaf, fi,
406 extent_end - start);
407 btrfs_mark_buffer_dirty(leaf);
408
409 if (disk_bytenr > 0) {
410 ret = btrfs_inc_extent_ref(trans, root,
411 disk_bytenr, num_bytes, 0,
412 root->root_key.objectid,
413 new_key.objectid,
414 start - extent_offset);
415 BUG_ON(ret);
416 *hint_byte = disk_bytenr;
417 }
418 key.offset = start;
419 }
420 /*
421 * | ---- range to drop ----- |
422 * | -------- extent -------- |
423 */
424 if (start <= key.offset && end < extent_end) {
425 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
426
427 memcpy(&new_key, &key, sizeof(new_key));
428 new_key.offset = end;
429 btrfs_set_item_key_safe(trans, root, path, &new_key);
430
431 extent_offset += end - key.offset;
432 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
433 btrfs_set_file_extent_num_bytes(leaf, fi,
434 extent_end - end);
435 btrfs_mark_buffer_dirty(leaf);
436 if (disk_bytenr > 0) {
437 inode_sub_bytes(inode, end - key.offset);
438 *hint_byte = disk_bytenr;
439 }
440 break;
441 }
442
443 search_start = extent_end;
444 /*
445 * | ---- range to drop ----- |
446 * | -------- extent -------- |
447 */
448 if (start > key.offset && end >= extent_end) {
449 BUG_ON(del_nr > 0);
450 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
451
452 btrfs_set_file_extent_num_bytes(leaf, fi,
453 start - key.offset);
454 btrfs_mark_buffer_dirty(leaf);
455 if (disk_bytenr > 0) {
456 inode_sub_bytes(inode, extent_end - start);
457 *hint_byte = disk_bytenr;
458 }
459 if (end == extent_end)
460 break;
461
462 path->slots[0]++;
463 goto next_slot;
464 }
465
466 /*
467 * | ---- range to drop ----- |
468 * | ------ extent ------ |
469 */
470 if (start <= key.offset && end >= extent_end) {
471 if (del_nr == 0) {
472 del_slot = path->slots[0];
473 del_nr = 1;
474 } else {
475 BUG_ON(del_slot + del_nr != path->slots[0]);
476 del_nr++;
477 }
478
479 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
480 inode_sub_bytes(inode,
481 extent_end - key.offset);
482 extent_end = ALIGN(extent_end,
483 root->sectorsize);
484 } else if (disk_bytenr > 0) {
485 ret = btrfs_free_extent(trans, root,
486 disk_bytenr, num_bytes, 0,
487 root->root_key.objectid,
488 key.objectid, key.offset -
489 extent_offset);
490 BUG_ON(ret);
491 inode_sub_bytes(inode,
492 extent_end - key.offset);
493 *hint_byte = disk_bytenr;
494 }
495
496 if (end == extent_end)
497 break;
498
499 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
500 path->slots[0]++;
501 goto next_slot;
502 }
503
504 ret = btrfs_del_items(trans, root, path, del_slot,
505 del_nr);
506 BUG_ON(ret);
507
508 del_nr = 0;
509 del_slot = 0;
510
511 btrfs_release_path(root, path);
512 continue;
513 }
514
515 BUG_ON(1);
516 }
517
518 if (del_nr > 0) {
519 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
520 BUG_ON(ret);
521 }
522
523 btrfs_free_path(path);
524 return ret;
525 }
526
527 static int extent_mergeable(struct extent_buffer *leaf, int slot,
528 u64 objectid, u64 bytenr, u64 orig_offset,
529 u64 *start, u64 *end)
530 {
531 struct btrfs_file_extent_item *fi;
532 struct btrfs_key key;
533 u64 extent_end;
534
535 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
536 return 0;
537
538 btrfs_item_key_to_cpu(leaf, &key, slot);
539 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
540 return 0;
541
542 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
543 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
544 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
545 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
546 btrfs_file_extent_compression(leaf, fi) ||
547 btrfs_file_extent_encryption(leaf, fi) ||
548 btrfs_file_extent_other_encoding(leaf, fi))
549 return 0;
550
551 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
552 if ((*start && *start != key.offset) || (*end && *end != extent_end))
553 return 0;
554
555 *start = key.offset;
556 *end = extent_end;
557 return 1;
558 }
559
560 /*
561 * Mark extent in the range start - end as written.
562 *
563 * This changes extent type from 'pre-allocated' to 'regular'. If only
564 * part of extent is marked as written, the extent will be split into
565 * two or three.
566 */
567 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
568 struct inode *inode, u64 start, u64 end)
569 {
570 struct btrfs_root *root = BTRFS_I(inode)->root;
571 struct extent_buffer *leaf;
572 struct btrfs_path *path;
573 struct btrfs_file_extent_item *fi;
574 struct btrfs_key key;
575 struct btrfs_key new_key;
576 u64 bytenr;
577 u64 num_bytes;
578 u64 extent_end;
579 u64 orig_offset;
580 u64 other_start;
581 u64 other_end;
582 u64 split;
583 int del_nr = 0;
584 int del_slot = 0;
585 int recow;
586 int ret;
587
588 btrfs_drop_extent_cache(inode, start, end - 1, 0);
589
590 path = btrfs_alloc_path();
591 BUG_ON(!path);
592 again:
593 recow = 0;
594 split = start;
595 key.objectid = inode->i_ino;
596 key.type = BTRFS_EXTENT_DATA_KEY;
597 key.offset = split;
598
599 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
600 if (ret > 0 && path->slots[0] > 0)
601 path->slots[0]--;
602
603 leaf = path->nodes[0];
604 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
605 BUG_ON(key.objectid != inode->i_ino ||
606 key.type != BTRFS_EXTENT_DATA_KEY);
607 fi = btrfs_item_ptr(leaf, path->slots[0],
608 struct btrfs_file_extent_item);
609 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
610 BTRFS_FILE_EXTENT_PREALLOC);
611 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
612 BUG_ON(key.offset > start || extent_end < end);
613
614 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
615 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
616 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
617 memcpy(&new_key, &key, sizeof(new_key));
618
619 if (start == key.offset && end < extent_end) {
620 other_start = 0;
621 other_end = start;
622 if (extent_mergeable(leaf, path->slots[0] - 1,
623 inode->i_ino, bytenr, orig_offset,
624 &other_start, &other_end)) {
625 new_key.offset = end;
626 btrfs_set_item_key_safe(trans, root, path, &new_key);
627 fi = btrfs_item_ptr(leaf, path->slots[0],
628 struct btrfs_file_extent_item);
629 btrfs_set_file_extent_num_bytes(leaf, fi,
630 extent_end - end);
631 btrfs_set_file_extent_offset(leaf, fi,
632 end - orig_offset);
633 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
634 struct btrfs_file_extent_item);
635 btrfs_set_file_extent_num_bytes(leaf, fi,
636 end - other_start);
637 btrfs_mark_buffer_dirty(leaf);
638 goto out;
639 }
640 }
641
642 if (start > key.offset && end == extent_end) {
643 other_start = end;
644 other_end = 0;
645 if (extent_mergeable(leaf, path->slots[0] + 1,
646 inode->i_ino, bytenr, orig_offset,
647 &other_start, &other_end)) {
648 fi = btrfs_item_ptr(leaf, path->slots[0],
649 struct btrfs_file_extent_item);
650 btrfs_set_file_extent_num_bytes(leaf, fi,
651 start - key.offset);
652 path->slots[0]++;
653 new_key.offset = start;
654 btrfs_set_item_key_safe(trans, root, path, &new_key);
655
656 fi = btrfs_item_ptr(leaf, path->slots[0],
657 struct btrfs_file_extent_item);
658 btrfs_set_file_extent_num_bytes(leaf, fi,
659 other_end - start);
660 btrfs_set_file_extent_offset(leaf, fi,
661 start - orig_offset);
662 btrfs_mark_buffer_dirty(leaf);
663 goto out;
664 }
665 }
666
667 while (start > key.offset || end < extent_end) {
668 if (key.offset == start)
669 split = end;
670
671 new_key.offset = split;
672 ret = btrfs_duplicate_item(trans, root, path, &new_key);
673 if (ret == -EAGAIN) {
674 btrfs_release_path(root, path);
675 goto again;
676 }
677 BUG_ON(ret < 0);
678
679 leaf = path->nodes[0];
680 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
681 struct btrfs_file_extent_item);
682 btrfs_set_file_extent_num_bytes(leaf, fi,
683 split - key.offset);
684
685 fi = btrfs_item_ptr(leaf, path->slots[0],
686 struct btrfs_file_extent_item);
687
688 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
689 btrfs_set_file_extent_num_bytes(leaf, fi,
690 extent_end - split);
691 btrfs_mark_buffer_dirty(leaf);
692
693 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
694 root->root_key.objectid,
695 inode->i_ino, orig_offset);
696 BUG_ON(ret);
697
698 if (split == start) {
699 key.offset = start;
700 } else {
701 BUG_ON(start != key.offset);
702 path->slots[0]--;
703 extent_end = end;
704 }
705 recow = 1;
706 }
707
708 other_start = end;
709 other_end = 0;
710 if (extent_mergeable(leaf, path->slots[0] + 1,
711 inode->i_ino, bytenr, orig_offset,
712 &other_start, &other_end)) {
713 if (recow) {
714 btrfs_release_path(root, path);
715 goto again;
716 }
717 extent_end = other_end;
718 del_slot = path->slots[0] + 1;
719 del_nr++;
720 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
721 0, root->root_key.objectid,
722 inode->i_ino, orig_offset);
723 BUG_ON(ret);
724 }
725 other_start = 0;
726 other_end = start;
727 if (extent_mergeable(leaf, path->slots[0] - 1,
728 inode->i_ino, bytenr, orig_offset,
729 &other_start, &other_end)) {
730 if (recow) {
731 btrfs_release_path(root, path);
732 goto again;
733 }
734 key.offset = other_start;
735 del_slot = path->slots[0];
736 del_nr++;
737 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
738 0, root->root_key.objectid,
739 inode->i_ino, orig_offset);
740 BUG_ON(ret);
741 }
742 if (del_nr == 0) {
743 fi = btrfs_item_ptr(leaf, path->slots[0],
744 struct btrfs_file_extent_item);
745 btrfs_set_file_extent_type(leaf, fi,
746 BTRFS_FILE_EXTENT_REG);
747 btrfs_mark_buffer_dirty(leaf);
748 } else {
749 fi = btrfs_item_ptr(leaf, del_slot - 1,
750 struct btrfs_file_extent_item);
751 btrfs_set_file_extent_type(leaf, fi,
752 BTRFS_FILE_EXTENT_REG);
753 btrfs_set_file_extent_num_bytes(leaf, fi,
754 extent_end - key.offset);
755 btrfs_mark_buffer_dirty(leaf);
756
757 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
758 BUG_ON(ret);
759 }
760 out:
761 btrfs_free_path(path);
762 return 0;
763 }
764
765 /*
766 * this gets pages into the page cache and locks them down, it also properly
767 * waits for data=ordered extents to finish before allowing the pages to be
768 * modified.
769 */
770 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
771 struct page **pages, size_t num_pages,
772 loff_t pos, unsigned long first_index,
773 unsigned long last_index, size_t write_bytes)
774 {
775 struct extent_state *cached_state = NULL;
776 int i;
777 unsigned long index = pos >> PAGE_CACHE_SHIFT;
778 struct inode *inode = fdentry(file)->d_inode;
779 int err = 0;
780 u64 start_pos;
781 u64 last_pos;
782
783 start_pos = pos & ~((u64)root->sectorsize - 1);
784 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
785
786 if (start_pos > inode->i_size) {
787 err = btrfs_cont_expand(inode, start_pos);
788 if (err)
789 return err;
790 }
791
792 memset(pages, 0, num_pages * sizeof(struct page *));
793 again:
794 for (i = 0; i < num_pages; i++) {
795 pages[i] = grab_cache_page(inode->i_mapping, index + i);
796 if (!pages[i]) {
797 int c;
798 for (c = i - 1; c >= 0; c--) {
799 unlock_page(pages[c]);
800 page_cache_release(pages[c]);
801 }
802 return -ENOMEM;
803 }
804 wait_on_page_writeback(pages[i]);
805 }
806 if (start_pos < inode->i_size) {
807 struct btrfs_ordered_extent *ordered;
808 lock_extent_bits(&BTRFS_I(inode)->io_tree,
809 start_pos, last_pos - 1, 0, &cached_state,
810 GFP_NOFS);
811 ordered = btrfs_lookup_first_ordered_extent(inode,
812 last_pos - 1);
813 if (ordered &&
814 ordered->file_offset + ordered->len > start_pos &&
815 ordered->file_offset < last_pos) {
816 btrfs_put_ordered_extent(ordered);
817 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
818 start_pos, last_pos - 1,
819 &cached_state, GFP_NOFS);
820 for (i = 0; i < num_pages; i++) {
821 unlock_page(pages[i]);
822 page_cache_release(pages[i]);
823 }
824 btrfs_wait_ordered_range(inode, start_pos,
825 last_pos - start_pos);
826 goto again;
827 }
828 if (ordered)
829 btrfs_put_ordered_extent(ordered);
830
831 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
832 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
833 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
834 GFP_NOFS);
835 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
836 start_pos, last_pos - 1, &cached_state,
837 GFP_NOFS);
838 }
839 for (i = 0; i < num_pages; i++) {
840 clear_page_dirty_for_io(pages[i]);
841 set_page_extent_mapped(pages[i]);
842 WARN_ON(!PageLocked(pages[i]));
843 }
844 return 0;
845 }
846
847 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
848 const struct iovec *iov,
849 unsigned long nr_segs, loff_t pos)
850 {
851 struct file *file = iocb->ki_filp;
852 struct inode *inode = fdentry(file)->d_inode;
853 struct btrfs_root *root = BTRFS_I(inode)->root;
854 struct page *pinned[2];
855 struct page **pages = NULL;
856 struct iov_iter i;
857 loff_t *ppos = &iocb->ki_pos;
858 loff_t start_pos;
859 ssize_t num_written = 0;
860 ssize_t err = 0;
861 size_t count;
862 size_t ocount;
863 int ret = 0;
864 int nrptrs;
865 unsigned long first_index;
866 unsigned long last_index;
867 int will_write;
868 int buffered = 0;
869 int copied = 0;
870 int dirty_pages = 0;
871
872 will_write = ((file->f_flags & O_DSYNC) || IS_SYNC(inode) ||
873 (file->f_flags & O_DIRECT));
874
875 pinned[0] = NULL;
876 pinned[1] = NULL;
877
878 start_pos = pos;
879
880 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
881
882 mutex_lock(&inode->i_mutex);
883
884 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
885 if (err)
886 goto out;
887 count = ocount;
888
889 current->backing_dev_info = inode->i_mapping->backing_dev_info;
890 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
891 if (err)
892 goto out;
893
894 if (count == 0)
895 goto out;
896
897 err = file_remove_suid(file);
898 if (err)
899 goto out;
900
901 /*
902 * If BTRFS flips readonly due to some impossible error
903 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
904 * although we have opened a file as writable, we have
905 * to stop this write operation to ensure FS consistency.
906 */
907 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
908 err = -EROFS;
909 goto out;
910 }
911
912 file_update_time(file);
913 BTRFS_I(inode)->sequence++;
914
915 if (unlikely(file->f_flags & O_DIRECT)) {
916 num_written = generic_file_direct_write(iocb, iov, &nr_segs,
917 pos, ppos, count,
918 ocount);
919 /*
920 * the generic O_DIRECT will update in-memory i_size after the
921 * DIOs are done. But our endio handlers that update the on
922 * disk i_size never update past the in memory i_size. So we
923 * need one more update here to catch any additions to the
924 * file
925 */
926 if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
927 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
928 mark_inode_dirty(inode);
929 }
930
931 if (num_written < 0) {
932 ret = num_written;
933 num_written = 0;
934 goto out;
935 } else if (num_written == count) {
936 /* pick up pos changes done by the generic code */
937 pos = *ppos;
938 goto out;
939 }
940 /*
941 * We are going to do buffered for the rest of the range, so we
942 * need to make sure to invalidate the buffered pages when we're
943 * done.
944 */
945 buffered = 1;
946 pos += num_written;
947 }
948
949 iov_iter_init(&i, iov, nr_segs, count, num_written);
950 nrptrs = min((iov_iter_count(&i) + PAGE_CACHE_SIZE - 1) /
951 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
952 (sizeof(struct page *)));
953 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
954 if (!pages) {
955 ret = -ENOMEM;
956 goto out;
957 }
958
959 /* generic_write_checks can change our pos */
960 start_pos = pos;
961
962 first_index = pos >> PAGE_CACHE_SHIFT;
963 last_index = (pos + iov_iter_count(&i)) >> PAGE_CACHE_SHIFT;
964
965 /*
966 * there are lots of better ways to do this, but this code
967 * makes sure the first and last page in the file range are
968 * up to date and ready for cow
969 */
970 if ((pos & (PAGE_CACHE_SIZE - 1))) {
971 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
972 if (!PageUptodate(pinned[0])) {
973 ret = btrfs_readpage(NULL, pinned[0]);
974 BUG_ON(ret);
975 wait_on_page_locked(pinned[0]);
976 } else {
977 unlock_page(pinned[0]);
978 }
979 }
980 if ((pos + iov_iter_count(&i)) & (PAGE_CACHE_SIZE - 1)) {
981 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
982 if (!PageUptodate(pinned[1])) {
983 ret = btrfs_readpage(NULL, pinned[1]);
984 BUG_ON(ret);
985 wait_on_page_locked(pinned[1]);
986 } else {
987 unlock_page(pinned[1]);
988 }
989 }
990
991 while (iov_iter_count(&i) > 0) {
992 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
993 size_t write_bytes = min(iov_iter_count(&i),
994 nrptrs * (size_t)PAGE_CACHE_SIZE -
995 offset);
996 size_t num_pages = (write_bytes + offset +
997 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
998
999 WARN_ON(num_pages > nrptrs);
1000 memset(pages, 0, sizeof(struct page *) * nrptrs);
1001
1002 /*
1003 * Fault pages before locking them in prepare_pages
1004 * to avoid recursive lock
1005 */
1006 if (unlikely(iov_iter_fault_in_readable(&i, write_bytes))) {
1007 ret = -EFAULT;
1008 goto out;
1009 }
1010
1011 ret = btrfs_delalloc_reserve_space(inode,
1012 num_pages << PAGE_CACHE_SHIFT);
1013 if (ret)
1014 goto out;
1015
1016 ret = prepare_pages(root, file, pages, num_pages,
1017 pos, first_index, last_index,
1018 write_bytes);
1019 if (ret) {
1020 btrfs_delalloc_release_space(inode,
1021 num_pages << PAGE_CACHE_SHIFT);
1022 goto out;
1023 }
1024
1025 copied = btrfs_copy_from_user(pos, num_pages,
1026 write_bytes, pages, &i);
1027 dirty_pages = (copied + offset + PAGE_CACHE_SIZE - 1) >>
1028 PAGE_CACHE_SHIFT;
1029
1030 if (num_pages > dirty_pages) {
1031 if (copied > 0)
1032 atomic_inc(
1033 &BTRFS_I(inode)->outstanding_extents);
1034 btrfs_delalloc_release_space(inode,
1035 (num_pages - dirty_pages) <<
1036 PAGE_CACHE_SHIFT);
1037 }
1038
1039 if (copied > 0) {
1040 dirty_and_release_pages(NULL, root, file, pages,
1041 dirty_pages, pos, copied);
1042 }
1043
1044 btrfs_drop_pages(pages, num_pages);
1045
1046 if (copied > 0) {
1047 if (will_write) {
1048 filemap_fdatawrite_range(inode->i_mapping, pos,
1049 pos + copied - 1);
1050 } else {
1051 balance_dirty_pages_ratelimited_nr(
1052 inode->i_mapping,
1053 dirty_pages);
1054 if (dirty_pages <
1055 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1056 btrfs_btree_balance_dirty(root, 1);
1057 btrfs_throttle(root);
1058 }
1059 }
1060
1061 pos += copied;
1062 num_written += copied;
1063
1064 cond_resched();
1065 }
1066 out:
1067 mutex_unlock(&inode->i_mutex);
1068 if (ret)
1069 err = ret;
1070
1071 kfree(pages);
1072 if (pinned[0])
1073 page_cache_release(pinned[0]);
1074 if (pinned[1])
1075 page_cache_release(pinned[1]);
1076 *ppos = pos;
1077
1078 /*
1079 * we want to make sure fsync finds this change
1080 * but we haven't joined a transaction running right now.
1081 *
1082 * Later on, someone is sure to update the inode and get the
1083 * real transid recorded.
1084 *
1085 * We set last_trans now to the fs_info generation + 1,
1086 * this will either be one more than the running transaction
1087 * or the generation used for the next transaction if there isn't
1088 * one running right now.
1089 */
1090 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1091
1092 if (num_written > 0 && will_write) {
1093 struct btrfs_trans_handle *trans;
1094
1095 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1096 if (err)
1097 num_written = err;
1098
1099 if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
1100 trans = btrfs_start_transaction(root, 0);
1101 if (IS_ERR(trans)) {
1102 num_written = PTR_ERR(trans);
1103 goto done;
1104 }
1105 mutex_lock(&inode->i_mutex);
1106 ret = btrfs_log_dentry_safe(trans, root,
1107 file->f_dentry);
1108 mutex_unlock(&inode->i_mutex);
1109 if (ret == 0) {
1110 ret = btrfs_sync_log(trans, root);
1111 if (ret == 0)
1112 btrfs_end_transaction(trans, root);
1113 else
1114 btrfs_commit_transaction(trans, root);
1115 } else if (ret != BTRFS_NO_LOG_SYNC) {
1116 btrfs_commit_transaction(trans, root);
1117 } else {
1118 btrfs_end_transaction(trans, root);
1119 }
1120 }
1121 if (file->f_flags & O_DIRECT && buffered) {
1122 invalidate_mapping_pages(inode->i_mapping,
1123 start_pos >> PAGE_CACHE_SHIFT,
1124 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1125 }
1126 }
1127 done:
1128 current->backing_dev_info = NULL;
1129 return num_written ? num_written : err;
1130 }
1131
1132 int btrfs_release_file(struct inode *inode, struct file *filp)
1133 {
1134 /*
1135 * ordered_data_close is set by settattr when we are about to truncate
1136 * a file from a non-zero size to a zero size. This tries to
1137 * flush down new bytes that may have been written if the
1138 * application were using truncate to replace a file in place.
1139 */
1140 if (BTRFS_I(inode)->ordered_data_close) {
1141 BTRFS_I(inode)->ordered_data_close = 0;
1142 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1143 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1144 filemap_flush(inode->i_mapping);
1145 }
1146 if (filp->private_data)
1147 btrfs_ioctl_trans_end(filp);
1148 return 0;
1149 }
1150
1151 /*
1152 * fsync call for both files and directories. This logs the inode into
1153 * the tree log instead of forcing full commits whenever possible.
1154 *
1155 * It needs to call filemap_fdatawait so that all ordered extent updates are
1156 * in the metadata btree are up to date for copying to the log.
1157 *
1158 * It drops the inode mutex before doing the tree log commit. This is an
1159 * important optimization for directories because holding the mutex prevents
1160 * new operations on the dir while we write to disk.
1161 */
1162 int btrfs_sync_file(struct file *file, int datasync)
1163 {
1164 struct dentry *dentry = file->f_path.dentry;
1165 struct inode *inode = dentry->d_inode;
1166 struct btrfs_root *root = BTRFS_I(inode)->root;
1167 int ret = 0;
1168 struct btrfs_trans_handle *trans;
1169
1170
1171 /* we wait first, since the writeback may change the inode */
1172 root->log_batch++;
1173 /* the VFS called filemap_fdatawrite for us */
1174 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1175 root->log_batch++;
1176
1177 /*
1178 * check the transaction that last modified this inode
1179 * and see if its already been committed
1180 */
1181 if (!BTRFS_I(inode)->last_trans)
1182 goto out;
1183
1184 /*
1185 * if the last transaction that changed this file was before
1186 * the current transaction, we can bail out now without any
1187 * syncing
1188 */
1189 mutex_lock(&root->fs_info->trans_mutex);
1190 if (BTRFS_I(inode)->last_trans <=
1191 root->fs_info->last_trans_committed) {
1192 BTRFS_I(inode)->last_trans = 0;
1193 mutex_unlock(&root->fs_info->trans_mutex);
1194 goto out;
1195 }
1196 mutex_unlock(&root->fs_info->trans_mutex);
1197
1198 /*
1199 * ok we haven't committed the transaction yet, lets do a commit
1200 */
1201 if (file->private_data)
1202 btrfs_ioctl_trans_end(file);
1203
1204 trans = btrfs_start_transaction(root, 0);
1205 if (IS_ERR(trans)) {
1206 ret = PTR_ERR(trans);
1207 goto out;
1208 }
1209
1210 ret = btrfs_log_dentry_safe(trans, root, dentry);
1211 if (ret < 0)
1212 goto out;
1213
1214 /* we've logged all the items and now have a consistent
1215 * version of the file in the log. It is possible that
1216 * someone will come in and modify the file, but that's
1217 * fine because the log is consistent on disk, and we
1218 * have references to all of the file's extents
1219 *
1220 * It is possible that someone will come in and log the
1221 * file again, but that will end up using the synchronization
1222 * inside btrfs_sync_log to keep things safe.
1223 */
1224 mutex_unlock(&dentry->d_inode->i_mutex);
1225
1226 if (ret != BTRFS_NO_LOG_SYNC) {
1227 if (ret > 0) {
1228 ret = btrfs_commit_transaction(trans, root);
1229 } else {
1230 ret = btrfs_sync_log(trans, root);
1231 if (ret == 0)
1232 ret = btrfs_end_transaction(trans, root);
1233 else
1234 ret = btrfs_commit_transaction(trans, root);
1235 }
1236 } else {
1237 ret = btrfs_end_transaction(trans, root);
1238 }
1239 mutex_lock(&dentry->d_inode->i_mutex);
1240 out:
1241 return ret > 0 ? -EIO : ret;
1242 }
1243
1244 static const struct vm_operations_struct btrfs_file_vm_ops = {
1245 .fault = filemap_fault,
1246 .page_mkwrite = btrfs_page_mkwrite,
1247 };
1248
1249 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1250 {
1251 struct address_space *mapping = filp->f_mapping;
1252
1253 if (!mapping->a_ops->readpage)
1254 return -ENOEXEC;
1255
1256 file_accessed(filp);
1257 vma->vm_ops = &btrfs_file_vm_ops;
1258 vma->vm_flags |= VM_CAN_NONLINEAR;
1259
1260 return 0;
1261 }
1262
1263 static long btrfs_fallocate(struct file *file, int mode,
1264 loff_t offset, loff_t len)
1265 {
1266 struct inode *inode = file->f_path.dentry->d_inode;
1267 struct extent_state *cached_state = NULL;
1268 u64 cur_offset;
1269 u64 last_byte;
1270 u64 alloc_start;
1271 u64 alloc_end;
1272 u64 alloc_hint = 0;
1273 u64 locked_end;
1274 u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1275 struct extent_map *em;
1276 int ret;
1277
1278 alloc_start = offset & ~mask;
1279 alloc_end = (offset + len + mask) & ~mask;
1280
1281 /* We only support the FALLOC_FL_KEEP_SIZE mode */
1282 if (mode & ~FALLOC_FL_KEEP_SIZE)
1283 return -EOPNOTSUPP;
1284
1285 /*
1286 * wait for ordered IO before we have any locks. We'll loop again
1287 * below with the locks held.
1288 */
1289 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1290
1291 mutex_lock(&inode->i_mutex);
1292 ret = inode_newsize_ok(inode, alloc_end);
1293 if (ret)
1294 goto out;
1295
1296 if (alloc_start > inode->i_size) {
1297 ret = btrfs_cont_expand(inode, alloc_start);
1298 if (ret)
1299 goto out;
1300 }
1301
1302 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
1303 if (ret)
1304 goto out;
1305
1306 locked_end = alloc_end - 1;
1307 while (1) {
1308 struct btrfs_ordered_extent *ordered;
1309
1310 /* the extent lock is ordered inside the running
1311 * transaction
1312 */
1313 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1314 locked_end, 0, &cached_state, GFP_NOFS);
1315 ordered = btrfs_lookup_first_ordered_extent(inode,
1316 alloc_end - 1);
1317 if (ordered &&
1318 ordered->file_offset + ordered->len > alloc_start &&
1319 ordered->file_offset < alloc_end) {
1320 btrfs_put_ordered_extent(ordered);
1321 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1322 alloc_start, locked_end,
1323 &cached_state, GFP_NOFS);
1324 /*
1325 * we can't wait on the range with the transaction
1326 * running or with the extent lock held
1327 */
1328 btrfs_wait_ordered_range(inode, alloc_start,
1329 alloc_end - alloc_start);
1330 } else {
1331 if (ordered)
1332 btrfs_put_ordered_extent(ordered);
1333 break;
1334 }
1335 }
1336
1337 cur_offset = alloc_start;
1338 while (1) {
1339 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1340 alloc_end - cur_offset, 0);
1341 BUG_ON(IS_ERR(em) || !em);
1342 last_byte = min(extent_map_end(em), alloc_end);
1343 last_byte = (last_byte + mask) & ~mask;
1344 if (em->block_start == EXTENT_MAP_HOLE ||
1345 (cur_offset >= inode->i_size &&
1346 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1347 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1348 last_byte - cur_offset,
1349 1 << inode->i_blkbits,
1350 offset + len,
1351 &alloc_hint);
1352 if (ret < 0) {
1353 free_extent_map(em);
1354 break;
1355 }
1356 }
1357 free_extent_map(em);
1358
1359 cur_offset = last_byte;
1360 if (cur_offset >= alloc_end) {
1361 ret = 0;
1362 break;
1363 }
1364 }
1365 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1366 &cached_state, GFP_NOFS);
1367
1368 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
1369 out:
1370 mutex_unlock(&inode->i_mutex);
1371 return ret;
1372 }
1373
1374 const struct file_operations btrfs_file_operations = {
1375 .llseek = generic_file_llseek,
1376 .read = do_sync_read,
1377 .write = do_sync_write,
1378 .aio_read = generic_file_aio_read,
1379 .splice_read = generic_file_splice_read,
1380 .aio_write = btrfs_file_aio_write,
1381 .mmap = btrfs_file_mmap,
1382 .open = generic_file_open,
1383 .release = btrfs_release_file,
1384 .fsync = btrfs_sync_file,
1385 .fallocate = btrfs_fallocate,
1386 .unlocked_ioctl = btrfs_ioctl,
1387 #ifdef CONFIG_COMPAT
1388 .compat_ioctl = btrfs_ioctl,
1389 #endif
1390 };
WandBoard kernel