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/gfp.h>
20 #include <linux/slab.h>
21 #include <linux/blkdev.h>
22 #include <linux/writeback.h>
23 #include <linux/pagevec.h>
24 #include "ctree.h"
25 #include "transaction.h"
26 #include "btrfs_inode.h"
27 #include "extent_io.h"
28
entry_end(struct btrfs_ordered_extent * entry)29 static u64 entry_end(struct btrfs_ordered_extent *entry)
30 {
31 if (entry->file_offset + entry->len < entry->file_offset)
32 return (u64)-1;
33 return entry->file_offset + entry->len;
34 }
35
36 /* returns NULL if the insertion worked, or it returns the node it did find
37 * in the tree
38 */
tree_insert(struct rb_root * root,u64 file_offset,struct rb_node * node)39 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
40 struct rb_node *node)
41 {
42 struct rb_node **p = &root->rb_node;
43 struct rb_node *parent = NULL;
44 struct btrfs_ordered_extent *entry;
45
46 while (*p) {
47 parent = *p;
48 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
49
50 if (file_offset < entry->file_offset)
51 p = &(*p)->rb_left;
52 else if (file_offset >= entry_end(entry))
53 p = &(*p)->rb_right;
54 else
55 return parent;
56 }
57
58 rb_link_node(node, parent, p);
59 rb_insert_color(node, root);
60 return NULL;
61 }
62
63 /*
64 * look for a given offset in the tree, and if it can't be found return the
65 * first lesser offset
66 */
__tree_search(struct rb_root * root,u64 file_offset,struct rb_node ** prev_ret)67 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
68 struct rb_node **prev_ret)
69 {
70 struct rb_node *n = root->rb_node;
71 struct rb_node *prev = NULL;
72 struct rb_node *test;
73 struct btrfs_ordered_extent *entry;
74 struct btrfs_ordered_extent *prev_entry = NULL;
75
76 while (n) {
77 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
78 prev = n;
79 prev_entry = entry;
80
81 if (file_offset < entry->file_offset)
82 n = n->rb_left;
83 else if (file_offset >= entry_end(entry))
84 n = n->rb_right;
85 else
86 return n;
87 }
88 if (!prev_ret)
89 return NULL;
90
91 while (prev && file_offset >= entry_end(prev_entry)) {
92 test = rb_next(prev);
93 if (!test)
94 break;
95 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
96 rb_node);
97 if (file_offset < entry_end(prev_entry))
98 break;
99
100 prev = test;
101 }
102 if (prev)
103 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
104 rb_node);
105 while (prev && file_offset < entry_end(prev_entry)) {
106 test = rb_prev(prev);
107 if (!test)
108 break;
109 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
110 rb_node);
111 prev = test;
112 }
113 *prev_ret = prev;
114 return NULL;
115 }
116
117 /*
118 * helper to check if a given offset is inside a given entry
119 */
offset_in_entry(struct btrfs_ordered_extent * entry,u64 file_offset)120 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
121 {
122 if (file_offset < entry->file_offset ||
123 entry->file_offset + entry->len <= file_offset)
124 return 0;
125 return 1;
126 }
127
128 /*
129 * look find the first ordered struct that has this offset, otherwise
130 * the first one less than this offset
131 */
tree_search(struct btrfs_ordered_inode_tree * tree,u64 file_offset)132 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
133 u64 file_offset)
134 {
135 struct rb_root *root = &tree->tree;
136 struct rb_node *prev;
137 struct rb_node *ret;
138 struct btrfs_ordered_extent *entry;
139
140 if (tree->last) {
141 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
142 rb_node);
143 if (offset_in_entry(entry, file_offset))
144 return tree->last;
145 }
146 ret = __tree_search(root, file_offset, &prev);
147 if (!ret)
148 ret = prev;
149 if (ret)
150 tree->last = ret;
151 return ret;
152 }
153
154 /* allocate and add a new ordered_extent into the per-inode tree.
155 * file_offset is the logical offset in the file
156 *
157 * start is the disk block number of an extent already reserved in the
158 * extent allocation tree
159 *
160 * len is the length of the extent
161 *
162 * This also sets the EXTENT_ORDERED bit on the range in the inode.
163 *
164 * The tree is given a single reference on the ordered extent that was
165 * inserted.
166 */
btrfs_add_ordered_extent(struct inode * inode,u64 file_offset,u64 start,u64 len,u64 disk_len,int type)167 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
168 u64 start, u64 len, u64 disk_len, int type)
169 {
170 struct btrfs_ordered_inode_tree *tree;
171 struct rb_node *node;
172 struct btrfs_ordered_extent *entry;
173
174 tree = &BTRFS_I(inode)->ordered_tree;
175 entry = kzalloc(sizeof(*entry), GFP_NOFS);
176 if (!entry)
177 return -ENOMEM;
178
179 mutex_lock(&tree->mutex);
180 entry->file_offset = file_offset;
181 entry->start = start;
182 entry->len = len;
183 entry->disk_len = disk_len;
184 entry->inode = inode;
185 if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
186 set_bit(type, &entry->flags);
187
188 /* one ref for the tree */
189 atomic_set(&entry->refs, 1);
190 init_waitqueue_head(&entry->wait);
191 INIT_LIST_HEAD(&entry->list);
192 INIT_LIST_HEAD(&entry->root_extent_list);
193
194 node = tree_insert(&tree->tree, file_offset,
195 &entry->rb_node);
196 BUG_ON(node);
197
198 set_extent_ordered(&BTRFS_I(inode)->io_tree, file_offset,
199 entry_end(entry) - 1, GFP_NOFS);
200
201 spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
202 list_add_tail(&entry->root_extent_list,
203 &BTRFS_I(inode)->root->fs_info->ordered_extents);
204 spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
205
206 mutex_unlock(&tree->mutex);
207 BUG_ON(node);
208 return 0;
209 }
210
211 /*
212 * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
213 * when an ordered extent is finished. If the list covers more than one
214 * ordered extent, it is split across multiples.
215 */
btrfs_add_ordered_sum(struct inode * inode,struct btrfs_ordered_extent * entry,struct btrfs_ordered_sum * sum)216 int btrfs_add_ordered_sum(struct inode *inode,
217 struct btrfs_ordered_extent *entry,
218 struct btrfs_ordered_sum *sum)
219 {
220 struct btrfs_ordered_inode_tree *tree;
221
222 tree = &BTRFS_I(inode)->ordered_tree;
223 mutex_lock(&tree->mutex);
224 list_add_tail(&sum->list, &entry->list);
225 mutex_unlock(&tree->mutex);
226 return 0;
227 }
228
229 /*
230 * this is used to account for finished IO across a given range
231 * of the file. The IO should not span ordered extents. If
232 * a given ordered_extent is completely done, 1 is returned, otherwise
233 * 0.
234 *
235 * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
236 * to make sure this function only returns 1 once for a given ordered extent.
237 */
btrfs_dec_test_ordered_pending(struct inode * inode,u64 file_offset,u64 io_size)238 int btrfs_dec_test_ordered_pending(struct inode *inode,
239 u64 file_offset, u64 io_size)
240 {
241 struct btrfs_ordered_inode_tree *tree;
242 struct rb_node *node;
243 struct btrfs_ordered_extent *entry;
244 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
245 int ret;
246
247 tree = &BTRFS_I(inode)->ordered_tree;
248 mutex_lock(&tree->mutex);
249 clear_extent_ordered(io_tree, file_offset, file_offset + io_size - 1,
250 GFP_NOFS);
251 node = tree_search(tree, file_offset);
252 if (!node) {
253 ret = 1;
254 goto out;
255 }
256
257 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
258 if (!offset_in_entry(entry, file_offset)) {
259 ret = 1;
260 goto out;
261 }
262
263 ret = test_range_bit(io_tree, entry->file_offset,
264 entry->file_offset + entry->len - 1,
265 EXTENT_ORDERED, 0);
266 if (ret == 0)
267 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
268 out:
269 mutex_unlock(&tree->mutex);
270 return ret == 0;
271 }
272
273 /*
274 * used to drop a reference on an ordered extent. This will free
275 * the extent if the last reference is dropped
276 */
btrfs_put_ordered_extent(struct btrfs_ordered_extent * entry)277 int btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
278 {
279 struct list_head *cur;
280 struct btrfs_ordered_sum *sum;
281
282 if (atomic_dec_and_test(&entry->refs)) {
283 while (!list_empty(&entry->list)) {
284 cur = entry->list.next;
285 sum = list_entry(cur, struct btrfs_ordered_sum, list);
286 list_del(&sum->list);
287 kfree(sum);
288 }
289 kfree(entry);
290 }
291 return 0;
292 }
293
294 /*
295 * remove an ordered extent from the tree. No references are dropped
296 * but, anyone waiting on this extent is woken up.
297 */
btrfs_remove_ordered_extent(struct inode * inode,struct btrfs_ordered_extent * entry)298 int btrfs_remove_ordered_extent(struct inode *inode,
299 struct btrfs_ordered_extent *entry)
300 {
301 struct btrfs_ordered_inode_tree *tree;
302 struct rb_node *node;
303
304 tree = &BTRFS_I(inode)->ordered_tree;
305 mutex_lock(&tree->mutex);
306 node = &entry->rb_node;
307 rb_erase(node, &tree->tree);
308 tree->last = NULL;
309 set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
310
311 spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
312 list_del_init(&entry->root_extent_list);
313 spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
314
315 mutex_unlock(&tree->mutex);
316 wake_up(&entry->wait);
317 return 0;
318 }
319
320 /*
321 * wait for all the ordered extents in a root. This is done when balancing
322 * space between drives.
323 */
btrfs_wait_ordered_extents(struct btrfs_root * root,int nocow_only)324 int btrfs_wait_ordered_extents(struct btrfs_root *root, int nocow_only)
325 {
326 struct list_head splice;
327 struct list_head *cur;
328 struct btrfs_ordered_extent *ordered;
329 struct inode *inode;
330
331 INIT_LIST_HEAD(&splice);
332
333 spin_lock(&root->fs_info->ordered_extent_lock);
334 list_splice_init(&root->fs_info->ordered_extents, &splice);
335 while (!list_empty(&splice)) {
336 cur = splice.next;
337 ordered = list_entry(cur, struct btrfs_ordered_extent,
338 root_extent_list);
339 if (nocow_only &&
340 !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags) &&
341 !test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags)) {
342 list_move(&ordered->root_extent_list,
343 &root->fs_info->ordered_extents);
344 cond_resched_lock(&root->fs_info->ordered_extent_lock);
345 continue;
346 }
347
348 list_del_init(&ordered->root_extent_list);
349 atomic_inc(&ordered->refs);
350
351 /*
352 * the inode may be getting freed (in sys_unlink path).
353 */
354 inode = igrab(ordered->inode);
355
356 spin_unlock(&root->fs_info->ordered_extent_lock);
357
358 if (inode) {
359 btrfs_start_ordered_extent(inode, ordered, 1);
360 btrfs_put_ordered_extent(ordered);
361 iput(inode);
362 } else {
363 btrfs_put_ordered_extent(ordered);
364 }
365
366 spin_lock(&root->fs_info->ordered_extent_lock);
367 }
368 spin_unlock(&root->fs_info->ordered_extent_lock);
369 return 0;
370 }
371
372 /*
373 * Used to start IO or wait for a given ordered extent to finish.
374 *
375 * If wait is one, this effectively waits on page writeback for all the pages
376 * in the extent, and it waits on the io completion code to insert
377 * metadata into the btree corresponding to the extent
378 */
btrfs_start_ordered_extent(struct inode * inode,struct btrfs_ordered_extent * entry,int wait)379 void btrfs_start_ordered_extent(struct inode *inode,
380 struct btrfs_ordered_extent *entry,
381 int wait)
382 {
383 u64 start = entry->file_offset;
384 u64 end = start + entry->len - 1;
385
386 /*
387 * pages in the range can be dirty, clean or writeback. We
388 * start IO on any dirty ones so the wait doesn't stall waiting
389 * for pdflush to find them
390 */
391 btrfs_fdatawrite_range(inode->i_mapping, start, end, WB_SYNC_ALL);
392 if (wait) {
393 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
394 &entry->flags));
395 }
396 }
397
398 /*
399 * Used to wait on ordered extents across a large range of bytes.
400 */
btrfs_wait_ordered_range(struct inode * inode,u64 start,u64 len)401 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
402 {
403 u64 end;
404 u64 orig_end;
405 u64 wait_end;
406 struct btrfs_ordered_extent *ordered;
407
408 if (start + len < start) {
409 orig_end = INT_LIMIT(loff_t);
410 } else {
411 orig_end = start + len - 1;
412 if (orig_end > INT_LIMIT(loff_t))
413 orig_end = INT_LIMIT(loff_t);
414 }
415 wait_end = orig_end;
416 again:
417 /* start IO across the range first to instantiate any delalloc
418 * extents
419 */
420 btrfs_fdatawrite_range(inode->i_mapping, start, orig_end, WB_SYNC_NONE);
421
422 /* The compression code will leave pages locked but return from
423 * writepage without setting the page writeback. Starting again
424 * with WB_SYNC_ALL will end up waiting for the IO to actually start.
425 */
426 btrfs_fdatawrite_range(inode->i_mapping, start, orig_end, WB_SYNC_ALL);
427
428 btrfs_wait_on_page_writeback_range(inode->i_mapping,
429 start >> PAGE_CACHE_SHIFT,
430 orig_end >> PAGE_CACHE_SHIFT);
431
432 end = orig_end;
433 while (1) {
434 ordered = btrfs_lookup_first_ordered_extent(inode, end);
435 if (!ordered)
436 break;
437 if (ordered->file_offset > orig_end) {
438 btrfs_put_ordered_extent(ordered);
439 break;
440 }
441 if (ordered->file_offset + ordered->len < start) {
442 btrfs_put_ordered_extent(ordered);
443 break;
444 }
445 btrfs_start_ordered_extent(inode, ordered, 1);
446 end = ordered->file_offset;
447 btrfs_put_ordered_extent(ordered);
448 if (end == 0 || end == start)
449 break;
450 end--;
451 }
452 if (test_range_bit(&BTRFS_I(inode)->io_tree, start, orig_end,
453 EXTENT_ORDERED | EXTENT_DELALLOC, 0)) {
454 schedule_timeout(1);
455 goto again;
456 }
457 return 0;
458 }
459
460 /*
461 * find an ordered extent corresponding to file_offset. return NULL if
462 * nothing is found, otherwise take a reference on the extent and return it
463 */
btrfs_lookup_ordered_extent(struct inode * inode,u64 file_offset)464 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
465 u64 file_offset)
466 {
467 struct btrfs_ordered_inode_tree *tree;
468 struct rb_node *node;
469 struct btrfs_ordered_extent *entry = NULL;
470
471 tree = &BTRFS_I(inode)->ordered_tree;
472 mutex_lock(&tree->mutex);
473 node = tree_search(tree, file_offset);
474 if (!node)
475 goto out;
476
477 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
478 if (!offset_in_entry(entry, file_offset))
479 entry = NULL;
480 if (entry)
481 atomic_inc(&entry->refs);
482 out:
483 mutex_unlock(&tree->mutex);
484 return entry;
485 }
486
487 /*
488 * lookup and return any extent before 'file_offset'. NULL is returned
489 * if none is found
490 */
491 struct btrfs_ordered_extent *
btrfs_lookup_first_ordered_extent(struct inode * inode,u64 file_offset)492 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
493 {
494 struct btrfs_ordered_inode_tree *tree;
495 struct rb_node *node;
496 struct btrfs_ordered_extent *entry = NULL;
497
498 tree = &BTRFS_I(inode)->ordered_tree;
499 mutex_lock(&tree->mutex);
500 node = tree_search(tree, file_offset);
501 if (!node)
502 goto out;
503
504 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
505 atomic_inc(&entry->refs);
506 out:
507 mutex_unlock(&tree->mutex);
508 return entry;
509 }
510
511 /*
512 * After an extent is done, call this to conditionally update the on disk
513 * i_size. i_size is updated to cover any fully written part of the file.
514 */
btrfs_ordered_update_i_size(struct inode * inode,struct btrfs_ordered_extent * ordered)515 int btrfs_ordered_update_i_size(struct inode *inode,
516 struct btrfs_ordered_extent *ordered)
517 {
518 struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
519 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
520 u64 disk_i_size;
521 u64 new_i_size;
522 u64 i_size_test;
523 struct rb_node *node;
524 struct btrfs_ordered_extent *test;
525
526 mutex_lock(&tree->mutex);
527 disk_i_size = BTRFS_I(inode)->disk_i_size;
528
529 /*
530 * if the disk i_size is already at the inode->i_size, or
531 * this ordered extent is inside the disk i_size, we're done
532 */
533 if (disk_i_size >= inode->i_size ||
534 ordered->file_offset + ordered->len <= disk_i_size) {
535 goto out;
536 }
537
538 /*
539 * we can't update the disk_isize if there are delalloc bytes
540 * between disk_i_size and this ordered extent
541 */
542 if (test_range_bit(io_tree, disk_i_size,
543 ordered->file_offset + ordered->len - 1,
544 EXTENT_DELALLOC, 0)) {
545 goto out;
546 }
547 /*
548 * walk backward from this ordered extent to disk_i_size.
549 * if we find an ordered extent then we can't update disk i_size
550 * yet
551 */
552 node = &ordered->rb_node;
553 while (1) {
554 node = rb_prev(node);
555 if (!node)
556 break;
557 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
558 if (test->file_offset + test->len <= disk_i_size)
559 break;
560 if (test->file_offset >= inode->i_size)
561 break;
562 if (test->file_offset >= disk_i_size)
563 goto out;
564 }
565 new_i_size = min_t(u64, entry_end(ordered), i_size_read(inode));
566
567 /*
568 * at this point, we know we can safely update i_size to at least
569 * the offset from this ordered extent. But, we need to
570 * walk forward and see if ios from higher up in the file have
571 * finished.
572 */
573 node = rb_next(&ordered->rb_node);
574 i_size_test = 0;
575 if (node) {
576 /*
577 * do we have an area where IO might have finished
578 * between our ordered extent and the next one.
579 */
580 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
581 if (test->file_offset > entry_end(ordered))
582 i_size_test = test->file_offset;
583 } else {
584 i_size_test = i_size_read(inode);
585 }
586
587 /*
588 * i_size_test is the end of a region after this ordered
589 * extent where there are no ordered extents. As long as there
590 * are no delalloc bytes in this area, it is safe to update
591 * disk_i_size to the end of the region.
592 */
593 if (i_size_test > entry_end(ordered) &&
594 !test_range_bit(io_tree, entry_end(ordered), i_size_test - 1,
595 EXTENT_DELALLOC, 0)) {
596 new_i_size = min_t(u64, i_size_test, i_size_read(inode));
597 }
598 BTRFS_I(inode)->disk_i_size = new_i_size;
599 out:
600 mutex_unlock(&tree->mutex);
601 return 0;
602 }
603
604 /*
605 * search the ordered extents for one corresponding to 'offset' and
606 * try to find a checksum. This is used because we allow pages to
607 * be reclaimed before their checksum is actually put into the btree
608 */
btrfs_find_ordered_sum(struct inode * inode,u64 offset,u64 disk_bytenr,u32 * sum)609 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
610 u32 *sum)
611 {
612 struct btrfs_ordered_sum *ordered_sum;
613 struct btrfs_sector_sum *sector_sums;
614 struct btrfs_ordered_extent *ordered;
615 struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
616 unsigned long num_sectors;
617 unsigned long i;
618 u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
619 int ret = 1;
620
621 ordered = btrfs_lookup_ordered_extent(inode, offset);
622 if (!ordered)
623 return 1;
624
625 mutex_lock(&tree->mutex);
626 list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
627 if (disk_bytenr >= ordered_sum->bytenr) {
628 num_sectors = ordered_sum->len / sectorsize;
629 sector_sums = ordered_sum->sums;
630 for (i = 0; i < num_sectors; i++) {
631 if (sector_sums[i].bytenr == disk_bytenr) {
632 *sum = sector_sums[i].sum;
633 ret = 0;
634 goto out;
635 }
636 }
637 }
638 }
639 out:
640 mutex_unlock(&tree->mutex);
641 btrfs_put_ordered_extent(ordered);
642 return ret;
643 }
644
645
646 /**
647 * taken from mm/filemap.c because it isn't exported
648 *
649 * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range
650 * @mapping: address space structure to write
651 * @start: offset in bytes where the range starts
652 * @end: offset in bytes where the range ends (inclusive)
653 * @sync_mode: enable synchronous operation
654 *
655 * Start writeback against all of a mapping's dirty pages that lie
656 * within the byte offsets <start, end> inclusive.
657 *
658 * If sync_mode is WB_SYNC_ALL then this is a "data integrity" operation, as
659 * opposed to a regular memory cleansing writeback. The difference between
660 * these two operations is that if a dirty page/buffer is encountered, it must
661 * be waited upon, and not just skipped over.
662 */
btrfs_fdatawrite_range(struct address_space * mapping,loff_t start,loff_t end,int sync_mode)663 int btrfs_fdatawrite_range(struct address_space *mapping, loff_t start,
664 loff_t end, int sync_mode)
665 {
666 struct writeback_control wbc = {
667 .sync_mode = sync_mode,
668 .nr_to_write = mapping->nrpages * 2,
669 .range_start = start,
670 .range_end = end,
671 .for_writepages = 1,
672 };
673 return btrfs_writepages(mapping, &wbc);
674 }
675
676 /**
677 * taken from mm/filemap.c because it isn't exported
678 *
679 * wait_on_page_writeback_range - wait for writeback to complete
680 * @mapping: target address_space
681 * @start: beginning page index
682 * @end: ending page index
683 *
684 * Wait for writeback to complete against pages indexed by start->end
685 * inclusive
686 */
btrfs_wait_on_page_writeback_range(struct address_space * mapping,pgoff_t start,pgoff_t end)687 int btrfs_wait_on_page_writeback_range(struct address_space *mapping,
688 pgoff_t start, pgoff_t end)
689 {
690 struct pagevec pvec;
691 int nr_pages;
692 int ret = 0;
693 pgoff_t index;
694
695 if (end < start)
696 return 0;
697
698 pagevec_init(&pvec, 0);
699 index = start;
700 while ((index <= end) &&
701 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
702 PAGECACHE_TAG_WRITEBACK,
703 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1)) != 0) {
704 unsigned i;
705
706 for (i = 0; i < nr_pages; i++) {
707 struct page *page = pvec.pages[i];
708
709 /* until radix tree lookup accepts end_index */
710 if (page->index > end)
711 continue;
712
713 wait_on_page_writeback(page);
714 if (PageError(page))
715 ret = -EIO;
716 }
717 pagevec_release(&pvec);
718 cond_resched();
719 }
720
721 /* Check for outstanding write errors */
722 if (test_and_clear_bit(AS_ENOSPC, &mapping->flags))
723 ret = -ENOSPC;
724 if (test_and_clear_bit(AS_EIO, &mapping->flags))
725 ret = -EIO;
726
727 return ret;
728 }
729