projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Btrfs: reduce lock contention during extent insertion
[deliverable/linux.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 * when auto defrag is enabled we
45 * queue up these defrag structs to remember which
46 * inodes need defragging passes
47 */
48 struct inode_defrag {
49 struct rb_node rb_node;
50 /* objectid */
51 u64 ino;
52 /*
53 * transid where the defrag was added, we search for
54 * extents newer than this
55 */
56 u64 transid;
57
58 /* root objectid */
59 u64 root;
60
61 /* last offset we were able to defrag */
62 u64 last_offset;
63
64 /* if we've wrapped around back to zero once already */
65 int cycled;
66 };
67
68 /* pop a record for an inode into the defrag tree. The lock
69 * must be held already
70 *
71 * If you're inserting a record for an older transid than an
72 * existing record, the transid already in the tree is lowered
73 *
74 * If an existing record is found the defrag item you
75 * pass in is freed
76 */
77 static void __btrfs_add_inode_defrag(struct inode *inode,
78 struct inode_defrag *defrag)
79 {
80 struct btrfs_root *root = BTRFS_I(inode)->root;
81 struct inode_defrag *entry;
82 struct rb_node **p;
83 struct rb_node *parent = NULL;
84
85 p = &root->fs_info->defrag_inodes.rb_node;
86 while (*p) {
87 parent = *p;
88 entry = rb_entry(parent, struct inode_defrag, rb_node);
89
90 if (defrag->ino < entry->ino)
91 p = &parent->rb_left;
92 else if (defrag->ino > entry->ino)
93 p = &parent->rb_right;
94 else {
95 /* if we're reinserting an entry for
96 * an old defrag run, make sure to
97 * lower the transid of our existing record
98 */
99 if (defrag->transid < entry->transid)
100 entry->transid = defrag->transid;
101 if (defrag->last_offset > entry->last_offset)
102 entry->last_offset = defrag->last_offset;
103 goto exists;
104 }
105 }
106 BTRFS_I(inode)->in_defrag = 1;
107 rb_link_node(&defrag->rb_node, parent, p);
108 rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
109 return;
110
111 exists:
112 kfree(defrag);
113 return;
114
115 }
116
117 /*
118 * insert a defrag record for this inode if auto defrag is
119 * enabled
120 */
121 int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
122 struct inode *inode)
123 {
124 struct btrfs_root *root = BTRFS_I(inode)->root;
125 struct inode_defrag *defrag;
126 u64 transid;
127
128 if (!btrfs_test_opt(root, AUTO_DEFRAG))
129 return 0;
130
131 if (btrfs_fs_closing(root->fs_info))
132 return 0;
133
134 if (BTRFS_I(inode)->in_defrag)
135 return 0;
136
137 if (trans)
138 transid = trans->transid;
139 else
140 transid = BTRFS_I(inode)->root->last_trans;
141
142 defrag = kzalloc(sizeof(*defrag), GFP_NOFS);
143 if (!defrag)
144 return -ENOMEM;
145
146 defrag->ino = btrfs_ino(inode);
147 defrag->transid = transid;
148 defrag->root = root->root_key.objectid;
149
150 spin_lock(&root->fs_info->defrag_inodes_lock);
151 if (!BTRFS_I(inode)->in_defrag)
152 __btrfs_add_inode_defrag(inode, defrag);
153 else
154 kfree(defrag);
155 spin_unlock(&root->fs_info->defrag_inodes_lock);
156 return 0;
157 }
158
159 /*
160 * must be called with the defrag_inodes lock held
161 */
162 struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info, u64 ino,
163 struct rb_node **next)
164 {
165 struct inode_defrag *entry = NULL;
166 struct rb_node *p;
167 struct rb_node *parent = NULL;
168
169 p = info->defrag_inodes.rb_node;
170 while (p) {
171 parent = p;
172 entry = rb_entry(parent, struct inode_defrag, rb_node);
173
174 if (ino < entry->ino)
175 p = parent->rb_left;
176 else if (ino > entry->ino)
177 p = parent->rb_right;
178 else
179 return entry;
180 }
181
182 if (next) {
183 while (parent && ino > entry->ino) {
184 parent = rb_next(parent);
185 entry = rb_entry(parent, struct inode_defrag, rb_node);
186 }
187 *next = parent;
188 }
189 return NULL;
190 }
191
192 /*
193 * run through the list of inodes in the FS that need
194 * defragging
195 */
196 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
197 {
198 struct inode_defrag *defrag;
199 struct btrfs_root *inode_root;
200 struct inode *inode;
201 struct rb_node *n;
202 struct btrfs_key key;
203 struct btrfs_ioctl_defrag_range_args range;
204 u64 first_ino = 0;
205 int num_defrag;
206 int defrag_batch = 1024;
207
208 memset(&range, 0, sizeof(range));
209 range.len = (u64)-1;
210
211 atomic_inc(&fs_info->defrag_running);
212 spin_lock(&fs_info->defrag_inodes_lock);
213 while(1) {
214 n = NULL;
215
216 /* find an inode to defrag */
217 defrag = btrfs_find_defrag_inode(fs_info, first_ino, &n);
218 if (!defrag) {
219 if (n)
220 defrag = rb_entry(n, struct inode_defrag, rb_node);
221 else if (first_ino) {
222 first_ino = 0;
223 continue;
224 } else {
225 break;
226 }
227 }
228
229 /* remove it from the rbtree */
230 first_ino = defrag->ino + 1;
231 rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
232
233 if (btrfs_fs_closing(fs_info))
234 goto next_free;
235
236 spin_unlock(&fs_info->defrag_inodes_lock);
237
238 /* get the inode */
239 key.objectid = defrag->root;
240 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
241 key.offset = (u64)-1;
242 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
243 if (IS_ERR(inode_root))
244 goto next;
245
246 key.objectid = defrag->ino;
247 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
248 key.offset = 0;
249
250 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
251 if (IS_ERR(inode))
252 goto next;
253
254 /* do a chunk of defrag */
255 BTRFS_I(inode)->in_defrag = 0;
256 range.start = defrag->last_offset;
257 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
258 defrag_batch);
259 /*
260 * if we filled the whole defrag batch, there
261 * must be more work to do. Queue this defrag
262 * again
263 */
264 if (num_defrag == defrag_batch) {
265 defrag->last_offset = range.start;
266 __btrfs_add_inode_defrag(inode, defrag);
267 /*
268 * we don't want to kfree defrag, we added it back to
269 * the rbtree
270 */
271 defrag = NULL;
272 } else if (defrag->last_offset && !defrag->cycled) {
273 /*
274 * we didn't fill our defrag batch, but
275 * we didn't start at zero. Make sure we loop
276 * around to the start of the file.
277 */
278 defrag->last_offset = 0;
279 defrag->cycled = 1;
280 __btrfs_add_inode_defrag(inode, defrag);
281 defrag = NULL;
282 }
283
284 iput(inode);
285 next:
286 spin_lock(&fs_info->defrag_inodes_lock);
287 next_free:
288 kfree(defrag);
289 }
290 spin_unlock(&fs_info->defrag_inodes_lock);
291
292 atomic_dec(&fs_info->defrag_running);
293
294 /*
295 * during unmount, we use the transaction_wait queue to
296 * wait for the defragger to stop
297 */
298 wake_up(&fs_info->transaction_wait);
299 return 0;
300 }
301
302 /* simple helper to fault in pages and copy. This should go away
303 * and be replaced with calls into generic code.
304 */
305 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
306 size_t write_bytes,
307 struct page **prepared_pages,
308 struct iov_iter *i)
309 {
310 size_t copied = 0;
311 size_t total_copied = 0;
312 int pg = 0;
313 int offset = pos & (PAGE_CACHE_SIZE - 1);
314
315 while (write_bytes > 0) {
316 size_t count = min_t(size_t,
317 PAGE_CACHE_SIZE - offset, write_bytes);
318 struct page *page = prepared_pages[pg];
319 /*
320 * Copy data from userspace to the current page
321 *
322 * Disable pagefault to avoid recursive lock since
323 * the pages are already locked
324 */
325 pagefault_disable();
326 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
327 pagefault_enable();
328
329 /* Flush processor's dcache for this page */
330 flush_dcache_page(page);
331
332 /*
333 * if we get a partial write, we can end up with
334 * partially up to date pages. These add
335 * a lot of complexity, so make sure they don't
336 * happen by forcing this copy to be retried.
337 *
338 * The rest of the btrfs_file_write code will fall
339 * back to page at a time copies after we return 0.
340 */
341 if (!PageUptodate(page) && copied < count)
342 copied = 0;
343
344 iov_iter_advance(i, copied);
345 write_bytes -= copied;
346 total_copied += copied;
347
348 /* Return to btrfs_file_aio_write to fault page */
349 if (unlikely(copied == 0))
350 break;
351
352 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
353 offset += copied;
354 } else {
355 pg++;
356 offset = 0;
357 }
358 }
359 return total_copied;
360 }
361
362 /*
363 * unlocks pages after btrfs_file_write is done with them
364 */
365 void btrfs_drop_pages(struct page **pages, size_t num_pages)
366 {
367 size_t i;
368 for (i = 0; i < num_pages; i++) {
369 /* page checked is some magic around finding pages that
370 * have been modified without going through btrfs_set_page_dirty
371 * clear it here
372 */
373 ClearPageChecked(pages[i]);
374 unlock_page(pages[i]);
375 mark_page_accessed(pages[i]);
376 page_cache_release(pages[i]);
377 }
378 }
379
380 /*
381 * after copy_from_user, pages need to be dirtied and we need to make
382 * sure holes are created between the current EOF and the start of
383 * any next extents (if required).
384 *
385 * this also makes the decision about creating an inline extent vs
386 * doing real data extents, marking pages dirty and delalloc as required.
387 */
388 int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
389 struct page **pages, size_t num_pages,
390 loff_t pos, size_t write_bytes,
391 struct extent_state **cached)
392 {
393 int err = 0;
394 int i;
395 u64 num_bytes;
396 u64 start_pos;
397 u64 end_of_last_block;
398 u64 end_pos = pos + write_bytes;
399 loff_t isize = i_size_read(inode);
400
401 start_pos = pos & ~((u64)root->sectorsize - 1);
402 num_bytes = (write_bytes + pos - start_pos +
403 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
404
405 end_of_last_block = start_pos + num_bytes - 1;
406 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
407 cached);
408 if (err)
409 return err;
410
411 for (i = 0; i < num_pages; i++) {
412 struct page *p = pages[i];
413 SetPageUptodate(p);
414 ClearPageChecked(p);
415 set_page_dirty(p);
416 }
417
418 /*
419 * we've only changed i_size in ram, and we haven't updated
420 * the disk i_size. There is no need to log the inode
421 * at this time.
422 */
423 if (end_pos > isize)
424 i_size_write(inode, end_pos);
425 return 0;
426 }
427
428 /*
429 * this drops all the extents in the cache that intersect the range
430 * [start, end]. Existing extents are split as required.
431 */
432 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
433 int skip_pinned)
434 {
435 struct extent_map *em;
436 struct extent_map *split = NULL;
437 struct extent_map *split2 = NULL;
438 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
439 u64 len = end - start + 1;
440 int ret;
441 int testend = 1;
442 unsigned long flags;
443 int compressed = 0;
444
445 WARN_ON(end < start);
446 if (end == (u64)-1) {
447 len = (u64)-1;
448 testend = 0;
449 }
450 while (1) {
451 if (!split)
452 split = alloc_extent_map();
453 if (!split2)
454 split2 = alloc_extent_map();
455 BUG_ON(!split || !split2); /* -ENOMEM */
456
457 write_lock(&em_tree->lock);
458 em = lookup_extent_mapping(em_tree, start, len);
459 if (!em) {
460 write_unlock(&em_tree->lock);
461 break;
462 }
463 flags = em->flags;
464 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
465 if (testend && em->start + em->len >= start + len) {
466 free_extent_map(em);
467 write_unlock(&em_tree->lock);
468 break;
469 }
470 start = em->start + em->len;
471 if (testend)
472 len = start + len - (em->start + em->len);
473 free_extent_map(em);
474 write_unlock(&em_tree->lock);
475 continue;
476 }
477 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
478 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
479 remove_extent_mapping(em_tree, em);
480
481 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
482 em->start < start) {
483 split->start = em->start;
484 split->len = start - em->start;
485 split->orig_start = em->orig_start;
486 split->block_start = em->block_start;
487
488 if (compressed)
489 split->block_len = em->block_len;
490 else
491 split->block_len = split->len;
492
493 split->bdev = em->bdev;
494 split->flags = flags;
495 split->compress_type = em->compress_type;
496 ret = add_extent_mapping(em_tree, split);
497 BUG_ON(ret); /* Logic error */
498 free_extent_map(split);
499 split = split2;
500 split2 = NULL;
501 }
502 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
503 testend && em->start + em->len > start + len) {
504 u64 diff = start + len - em->start;
505
506 split->start = start + len;
507 split->len = em->start + em->len - (start + len);
508 split->bdev = em->bdev;
509 split->flags = flags;
510 split->compress_type = em->compress_type;
511
512 if (compressed) {
513 split->block_len = em->block_len;
514 split->block_start = em->block_start;
515 split->orig_start = em->orig_start;
516 } else {
517 split->block_len = split->len;
518 split->block_start = em->block_start + diff;
519 split->orig_start = split->start;
520 }
521
522 ret = add_extent_mapping(em_tree, split);
523 BUG_ON(ret); /* Logic error */
524 free_extent_map(split);
525 split = NULL;
526 }
527 write_unlock(&em_tree->lock);
528
529 /* once for us */
530 free_extent_map(em);
531 /* once for the tree*/
532 free_extent_map(em);
533 }
534 if (split)
535 free_extent_map(split);
536 if (split2)
537 free_extent_map(split2);
538 return 0;
539 }
540
541 /*
542 * this is very complex, but the basic idea is to drop all extents
543 * in the range start - end. hint_block is filled in with a block number
544 * that would be a good hint to the block allocator for this file.
545 *
546 * If an extent intersects the range but is not entirely inside the range
547 * it is either truncated or split. Anything entirely inside the range
548 * is deleted from the tree.
549 */
550 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
551 u64 start, u64 end, u64 *hint_byte, int drop_cache)
552 {
553 struct btrfs_root *root = BTRFS_I(inode)->root;
554 struct extent_buffer *leaf;
555 struct btrfs_file_extent_item *fi;
556 struct btrfs_path *path;
557 struct btrfs_key key;
558 struct btrfs_key new_key;
559 u64 ino = btrfs_ino(inode);
560 u64 search_start = start;
561 u64 disk_bytenr = 0;
562 u64 num_bytes = 0;
563 u64 extent_offset = 0;
564 u64 extent_end = 0;
565 int del_nr = 0;
566 int del_slot = 0;
567 int extent_type;
568 int recow;
569 int ret;
570 int modify_tree = -1;
571
572 if (drop_cache)
573 btrfs_drop_extent_cache(inode, start, end - 1, 0);
574
575 path = btrfs_alloc_path();
576 if (!path)
577 return -ENOMEM;
578
579 if (start >= BTRFS_I(inode)->disk_i_size)
580 modify_tree = 0;
581
582 while (1) {
583 recow = 0;
584 ret = btrfs_lookup_file_extent(trans, root, path, ino,
585 search_start, modify_tree);
586 if (ret < 0)
587 break;
588 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
589 leaf = path->nodes[0];
590 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
591 if (key.objectid == ino &&
592 key.type == BTRFS_EXTENT_DATA_KEY)
593 path->slots[0]--;
594 }
595 ret = 0;
596 next_slot:
597 leaf = path->nodes[0];
598 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
599 BUG_ON(del_nr > 0);
600 ret = btrfs_next_leaf(root, path);
601 if (ret < 0)
602 break;
603 if (ret > 0) {
604 ret = 0;
605 break;
606 }
607 leaf = path->nodes[0];
608 recow = 1;
609 }
610
611 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
612 if (key.objectid > ino ||
613 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
614 break;
615
616 fi = btrfs_item_ptr(leaf, path->slots[0],
617 struct btrfs_file_extent_item);
618 extent_type = btrfs_file_extent_type(leaf, fi);
619
620 if (extent_type == BTRFS_FILE_EXTENT_REG ||
621 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
622 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
623 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
624 extent_offset = btrfs_file_extent_offset(leaf, fi);
625 extent_end = key.offset +
626 btrfs_file_extent_num_bytes(leaf, fi);
627 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
628 extent_end = key.offset +
629 btrfs_file_extent_inline_len(leaf, fi);
630 } else {
631 WARN_ON(1);
632 extent_end = search_start;
633 }
634
635 if (extent_end <= search_start) {
636 path->slots[0]++;
637 goto next_slot;
638 }
639
640 search_start = max(key.offset, start);
641 if (recow || !modify_tree) {
642 modify_tree = -1;
643 btrfs_release_path(path);
644 continue;
645 }
646
647 /*
648 * | - range to drop - |
649 * | -------- extent -------- |
650 */
651 if (start > key.offset && end < extent_end) {
652 BUG_ON(del_nr > 0);
653 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
654
655 memcpy(&new_key, &key, sizeof(new_key));
656 new_key.offset = start;
657 ret = btrfs_duplicate_item(trans, root, path,
658 &new_key);
659 if (ret == -EAGAIN) {
660 btrfs_release_path(path);
661 continue;
662 }
663 if (ret < 0)
664 break;
665
666 leaf = path->nodes[0];
667 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
668 struct btrfs_file_extent_item);
669 btrfs_set_file_extent_num_bytes(leaf, fi,
670 start - key.offset);
671
672 fi = btrfs_item_ptr(leaf, path->slots[0],
673 struct btrfs_file_extent_item);
674
675 extent_offset += start - key.offset;
676 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
677 btrfs_set_file_extent_num_bytes(leaf, fi,
678 extent_end - start);
679 btrfs_mark_buffer_dirty(leaf);
680
681 if (disk_bytenr > 0) {
682 ret = btrfs_inc_extent_ref(trans, root,
683 disk_bytenr, num_bytes, 0,
684 root->root_key.objectid,
685 new_key.objectid,
686 start - extent_offset, 0);
687 BUG_ON(ret); /* -ENOMEM */
688 *hint_byte = disk_bytenr;
689 }
690 key.offset = start;
691 }
692 /*
693 * | ---- range to drop ----- |
694 * | -------- extent -------- |
695 */
696 if (start <= key.offset && end < extent_end) {
697 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
698
699 memcpy(&new_key, &key, sizeof(new_key));
700 new_key.offset = end;
701 btrfs_set_item_key_safe(trans, root, path, &new_key);
702
703 extent_offset += end - key.offset;
704 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
705 btrfs_set_file_extent_num_bytes(leaf, fi,
706 extent_end - end);
707 btrfs_mark_buffer_dirty(leaf);
708 if (disk_bytenr > 0) {
709 inode_sub_bytes(inode, end - key.offset);
710 *hint_byte = disk_bytenr;
711 }
712 break;
713 }
714
715 search_start = extent_end;
716 /*
717 * | ---- range to drop ----- |
718 * | -------- extent -------- |
719 */
720 if (start > key.offset && end >= extent_end) {
721 BUG_ON(del_nr > 0);
722 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
723
724 btrfs_set_file_extent_num_bytes(leaf, fi,
725 start - key.offset);
726 btrfs_mark_buffer_dirty(leaf);
727 if (disk_bytenr > 0) {
728 inode_sub_bytes(inode, extent_end - start);
729 *hint_byte = disk_bytenr;
730 }
731 if (end == extent_end)
732 break;
733
734 path->slots[0]++;
735 goto next_slot;
736 }
737
738 /*
739 * | ---- range to drop ----- |
740 * | ------ extent ------ |
741 */
742 if (start <= key.offset && end >= extent_end) {
743 if (del_nr == 0) {
744 del_slot = path->slots[0];
745 del_nr = 1;
746 } else {
747 BUG_ON(del_slot + del_nr != path->slots[0]);
748 del_nr++;
749 }
750
751 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
752 inode_sub_bytes(inode,
753 extent_end - key.offset);
754 extent_end = ALIGN(extent_end,
755 root->sectorsize);
756 } else if (disk_bytenr > 0) {
757 ret = btrfs_free_extent(trans, root,
758 disk_bytenr, num_bytes, 0,
759 root->root_key.objectid,
760 key.objectid, key.offset -
761 extent_offset, 0);
762 BUG_ON(ret); /* -ENOMEM */
763 inode_sub_bytes(inode,
764 extent_end - key.offset);
765 *hint_byte = disk_bytenr;
766 }
767
768 if (end == extent_end)
769 break;
770
771 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
772 path->slots[0]++;
773 goto next_slot;
774 }
775
776 ret = btrfs_del_items(trans, root, path, del_slot,
777 del_nr);
778 if (ret) {
779 btrfs_abort_transaction(trans, root, ret);
780 goto out;
781 }
782
783 del_nr = 0;
784 del_slot = 0;
785
786 btrfs_release_path(path);
787 continue;
788 }
789
790 BUG_ON(1);
791 }
792
793 if (!ret && del_nr > 0) {
794 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
795 if (ret)
796 btrfs_abort_transaction(trans, root, ret);
797 }
798
799 out:
800 btrfs_free_path(path);
801 return ret;
802 }
803
804 static int extent_mergeable(struct extent_buffer *leaf, int slot,
805 u64 objectid, u64 bytenr, u64 orig_offset,
806 u64 *start, u64 *end)
807 {
808 struct btrfs_file_extent_item *fi;
809 struct btrfs_key key;
810 u64 extent_end;
811
812 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
813 return 0;
814
815 btrfs_item_key_to_cpu(leaf, &key, slot);
816 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
817 return 0;
818
819 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
820 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
821 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
822 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
823 btrfs_file_extent_compression(leaf, fi) ||
824 btrfs_file_extent_encryption(leaf, fi) ||
825 btrfs_file_extent_other_encoding(leaf, fi))
826 return 0;
827
828 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
829 if ((*start && *start != key.offset) || (*end && *end != extent_end))
830 return 0;
831
832 *start = key.offset;
833 *end = extent_end;
834 return 1;
835 }
836
837 /*
838 * Mark extent in the range start - end as written.
839 *
840 * This changes extent type from 'pre-allocated' to 'regular'. If only
841 * part of extent is marked as written, the extent will be split into
842 * two or three.
843 */
844 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
845 struct inode *inode, u64 start, u64 end)
846 {
847 struct btrfs_root *root = BTRFS_I(inode)->root;
848 struct extent_buffer *leaf;
849 struct btrfs_path *path;
850 struct btrfs_file_extent_item *fi;
851 struct btrfs_key key;
852 struct btrfs_key new_key;
853 u64 bytenr;
854 u64 num_bytes;
855 u64 extent_end;
856 u64 orig_offset;
857 u64 other_start;
858 u64 other_end;
859 u64 split;
860 int del_nr = 0;
861 int del_slot = 0;
862 int recow;
863 int ret;
864 u64 ino = btrfs_ino(inode);
865
866 btrfs_drop_extent_cache(inode, start, end - 1, 0);
867
868 path = btrfs_alloc_path();
869 if (!path)
870 return -ENOMEM;
871 again:
872 recow = 0;
873 split = start;
874 key.objectid = ino;
875 key.type = BTRFS_EXTENT_DATA_KEY;
876 key.offset = split;
877
878 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
879 if (ret < 0)
880 goto out;
881 if (ret > 0 && path->slots[0] > 0)
882 path->slots[0]--;
883
884 leaf = path->nodes[0];
885 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
886 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
887 fi = btrfs_item_ptr(leaf, path->slots[0],
888 struct btrfs_file_extent_item);
889 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
890 BTRFS_FILE_EXTENT_PREALLOC);
891 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
892 BUG_ON(key.offset > start || extent_end < end);
893
894 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
895 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
896 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
897 memcpy(&new_key, &key, sizeof(new_key));
898
899 if (start == key.offset && end < extent_end) {
900 other_start = 0;
901 other_end = start;
902 if (extent_mergeable(leaf, path->slots[0] - 1,
903 ino, bytenr, orig_offset,
904 &other_start, &other_end)) {
905 new_key.offset = end;
906 btrfs_set_item_key_safe(trans, root, path, &new_key);
907 fi = btrfs_item_ptr(leaf, path->slots[0],
908 struct btrfs_file_extent_item);
909 btrfs_set_file_extent_num_bytes(leaf, fi,
910 extent_end - end);
911 btrfs_set_file_extent_offset(leaf, fi,
912 end - orig_offset);
913 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
914 struct btrfs_file_extent_item);
915 btrfs_set_file_extent_num_bytes(leaf, fi,
916 end - other_start);
917 btrfs_mark_buffer_dirty(leaf);
918 goto out;
919 }
920 }
921
922 if (start > key.offset && end == extent_end) {
923 other_start = end;
924 other_end = 0;
925 if (extent_mergeable(leaf, path->slots[0] + 1,
926 ino, bytenr, orig_offset,
927 &other_start, &other_end)) {
928 fi = btrfs_item_ptr(leaf, path->slots[0],
929 struct btrfs_file_extent_item);
930 btrfs_set_file_extent_num_bytes(leaf, fi,
931 start - key.offset);
932 path->slots[0]++;
933 new_key.offset = start;
934 btrfs_set_item_key_safe(trans, root, path, &new_key);
935
936 fi = btrfs_item_ptr(leaf, path->slots[0],
937 struct btrfs_file_extent_item);
938 btrfs_set_file_extent_num_bytes(leaf, fi,
939 other_end - start);
940 btrfs_set_file_extent_offset(leaf, fi,
941 start - orig_offset);
942 btrfs_mark_buffer_dirty(leaf);
943 goto out;
944 }
945 }
946
947 while (start > key.offset || end < extent_end) {
948 if (key.offset == start)
949 split = end;
950
951 new_key.offset = split;
952 ret = btrfs_duplicate_item(trans, root, path, &new_key);
953 if (ret == -EAGAIN) {
954 btrfs_release_path(path);
955 goto again;
956 }
957 if (ret < 0) {
958 btrfs_abort_transaction(trans, root, ret);
959 goto out;
960 }
961
962 leaf = path->nodes[0];
963 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
964 struct btrfs_file_extent_item);
965 btrfs_set_file_extent_num_bytes(leaf, fi,
966 split - key.offset);
967
968 fi = btrfs_item_ptr(leaf, path->slots[0],
969 struct btrfs_file_extent_item);
970
971 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
972 btrfs_set_file_extent_num_bytes(leaf, fi,
973 extent_end - split);
974 btrfs_mark_buffer_dirty(leaf);
975
976 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
977 root->root_key.objectid,
978 ino, orig_offset, 0);
979 BUG_ON(ret); /* -ENOMEM */
980
981 if (split == start) {
982 key.offset = start;
983 } else {
984 BUG_ON(start != key.offset);
985 path->slots[0]--;
986 extent_end = end;
987 }
988 recow = 1;
989 }
990
991 other_start = end;
992 other_end = 0;
993 if (extent_mergeable(leaf, path->slots[0] + 1,
994 ino, bytenr, orig_offset,
995 &other_start, &other_end)) {
996 if (recow) {
997 btrfs_release_path(path);
998 goto again;
999 }
1000 extent_end = other_end;
1001 del_slot = path->slots[0] + 1;
1002 del_nr++;
1003 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1004 0, root->root_key.objectid,
1005 ino, orig_offset, 0);
1006 BUG_ON(ret); /* -ENOMEM */
1007 }
1008 other_start = 0;
1009 other_end = start;
1010 if (extent_mergeable(leaf, path->slots[0] - 1,
1011 ino, bytenr, orig_offset,
1012 &other_start, &other_end)) {
1013 if (recow) {
1014 btrfs_release_path(path);
1015 goto again;
1016 }
1017 key.offset = other_start;
1018 del_slot = path->slots[0];
1019 del_nr++;
1020 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1021 0, root->root_key.objectid,
1022 ino, orig_offset, 0);
1023 BUG_ON(ret); /* -ENOMEM */
1024 }
1025 if (del_nr == 0) {
1026 fi = btrfs_item_ptr(leaf, path->slots[0],
1027 struct btrfs_file_extent_item);
1028 btrfs_set_file_extent_type(leaf, fi,
1029 BTRFS_FILE_EXTENT_REG);
1030 btrfs_mark_buffer_dirty(leaf);
1031 } else {
1032 fi = btrfs_item_ptr(leaf, del_slot - 1,
1033 struct btrfs_file_extent_item);
1034 btrfs_set_file_extent_type(leaf, fi,
1035 BTRFS_FILE_EXTENT_REG);
1036 btrfs_set_file_extent_num_bytes(leaf, fi,
1037 extent_end - key.offset);
1038 btrfs_mark_buffer_dirty(leaf);
1039
1040 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1041 if (ret < 0) {
1042 btrfs_abort_transaction(trans, root, ret);
1043 goto out;
1044 }
1045 }
1046 out:
1047 btrfs_free_path(path);
1048 return 0;
1049 }
1050
1051 /*
1052 * on error we return an unlocked page and the error value
1053 * on success we return a locked page and 0
1054 */
1055 static int prepare_uptodate_page(struct page *page, u64 pos,
1056 bool force_uptodate)
1057 {
1058 int ret = 0;
1059
1060 if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
1061 !PageUptodate(page)) {
1062 ret = btrfs_readpage(NULL, page);
1063 if (ret)
1064 return ret;
1065 lock_page(page);
1066 if (!PageUptodate(page)) {
1067 unlock_page(page);
1068 return -EIO;
1069 }
1070 }
1071 return 0;
1072 }
1073
1074 /*
1075 * this gets pages into the page cache and locks them down, it also properly
1076 * waits for data=ordered extents to finish before allowing the pages to be
1077 * modified.
1078 */
1079 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1080 struct page **pages, size_t num_pages,
1081 loff_t pos, unsigned long first_index,
1082 size_t write_bytes, bool force_uptodate)
1083 {
1084 struct extent_state *cached_state = NULL;
1085 int i;
1086 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1087 struct inode *inode = fdentry(file)->d_inode;
1088 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1089 int err = 0;
1090 int faili = 0;
1091 u64 start_pos;
1092 u64 last_pos;
1093
1094 start_pos = pos & ~((u64)root->sectorsize - 1);
1095 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1096
1097 again:
1098 for (i = 0; i < num_pages; i++) {
1099 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1100 mask | __GFP_WRITE);
1101 if (!pages[i]) {
1102 faili = i - 1;
1103 err = -ENOMEM;
1104 goto fail;
1105 }
1106
1107 if (i == 0)
1108 err = prepare_uptodate_page(pages[i], pos,
1109 force_uptodate);
1110 if (i == num_pages - 1)
1111 err = prepare_uptodate_page(pages[i],
1112 pos + write_bytes, false);
1113 if (err) {
1114 page_cache_release(pages[i]);
1115 faili = i - 1;
1116 goto fail;
1117 }
1118 wait_on_page_writeback(pages[i]);
1119 }
1120 err = 0;
1121 if (start_pos < inode->i_size) {
1122 struct btrfs_ordered_extent *ordered;
1123 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1124 start_pos, last_pos - 1, 0, &cached_state);
1125 ordered = btrfs_lookup_first_ordered_extent(inode,
1126 last_pos - 1);
1127 if (ordered &&
1128 ordered->file_offset + ordered->len > start_pos &&
1129 ordered->file_offset < last_pos) {
1130 btrfs_put_ordered_extent(ordered);
1131 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1132 start_pos, last_pos - 1,
1133 &cached_state, GFP_NOFS);
1134 for (i = 0; i < num_pages; i++) {
1135 unlock_page(pages[i]);
1136 page_cache_release(pages[i]);
1137 }
1138 btrfs_wait_ordered_range(inode, start_pos,
1139 last_pos - start_pos);
1140 goto again;
1141 }
1142 if (ordered)
1143 btrfs_put_ordered_extent(ordered);
1144
1145 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1146 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1147 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
1148 GFP_NOFS);
1149 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1150 start_pos, last_pos - 1, &cached_state,
1151 GFP_NOFS);
1152 }
1153 for (i = 0; i < num_pages; i++) {
1154 if (clear_page_dirty_for_io(pages[i]))
1155 account_page_redirty(pages[i]);
1156 set_page_extent_mapped(pages[i]);
1157 WARN_ON(!PageLocked(pages[i]));
1158 }
1159 return 0;
1160 fail:
1161 while (faili >= 0) {
1162 unlock_page(pages[faili]);
1163 page_cache_release(pages[faili]);
1164 faili--;
1165 }
1166 return err;
1167
1168 }
1169
1170 static noinline ssize_t __btrfs_buffered_write(struct file *file,
1171 struct iov_iter *i,
1172 loff_t pos)
1173 {
1174 struct inode *inode = fdentry(file)->d_inode;
1175 struct btrfs_root *root = BTRFS_I(inode)->root;
1176 struct page **pages = NULL;
1177 unsigned long first_index;
1178 size_t num_written = 0;
1179 int nrptrs;
1180 int ret = 0;
1181 bool force_page_uptodate = false;
1182
1183 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1184 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1185 (sizeof(struct page *)));
1186 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1187 nrptrs = max(nrptrs, 8);
1188 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1189 if (!pages)
1190 return -ENOMEM;
1191
1192 first_index = pos >> PAGE_CACHE_SHIFT;
1193
1194 while (iov_iter_count(i) > 0) {
1195 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1196 size_t write_bytes = min(iov_iter_count(i),
1197 nrptrs * (size_t)PAGE_CACHE_SIZE -
1198 offset);
1199 size_t num_pages = (write_bytes + offset +
1200 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1201 size_t dirty_pages;
1202 size_t copied;
1203
1204 WARN_ON(num_pages > nrptrs);
1205
1206 /*
1207 * Fault pages before locking them in prepare_pages
1208 * to avoid recursive lock
1209 */
1210 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1211 ret = -EFAULT;
1212 break;
1213 }
1214
1215 ret = btrfs_delalloc_reserve_space(inode,
1216 num_pages << PAGE_CACHE_SHIFT);
1217 if (ret)
1218 break;
1219
1220 /*
1221 * This is going to setup the pages array with the number of
1222 * pages we want, so we don't really need to worry about the
1223 * contents of pages from loop to loop
1224 */
1225 ret = prepare_pages(root, file, pages, num_pages,
1226 pos, first_index, write_bytes,
1227 force_page_uptodate);
1228 if (ret) {
1229 btrfs_delalloc_release_space(inode,
1230 num_pages << PAGE_CACHE_SHIFT);
1231 break;
1232 }
1233
1234 copied = btrfs_copy_from_user(pos, num_pages,
1235 write_bytes, pages, i);
1236
1237 /*
1238 * if we have trouble faulting in the pages, fall
1239 * back to one page at a time
1240 */
1241 if (copied < write_bytes)
1242 nrptrs = 1;
1243
1244 if (copied == 0) {
1245 force_page_uptodate = true;
1246 dirty_pages = 0;
1247 } else {
1248 force_page_uptodate = false;
1249 dirty_pages = (copied + offset +
1250 PAGE_CACHE_SIZE - 1) >>
1251 PAGE_CACHE_SHIFT;
1252 }
1253
1254 /*
1255 * If we had a short copy we need to release the excess delaloc
1256 * bytes we reserved. We need to increment outstanding_extents
1257 * because btrfs_delalloc_release_space will decrement it, but
1258 * we still have an outstanding extent for the chunk we actually
1259 * managed to copy.
1260 */
1261 if (num_pages > dirty_pages) {
1262 if (copied > 0) {
1263 spin_lock(&BTRFS_I(inode)->lock);
1264 BTRFS_I(inode)->outstanding_extents++;
1265 spin_unlock(&BTRFS_I(inode)->lock);
1266 }
1267 btrfs_delalloc_release_space(inode,
1268 (num_pages - dirty_pages) <<
1269 PAGE_CACHE_SHIFT);
1270 }
1271
1272 if (copied > 0) {
1273 ret = btrfs_dirty_pages(root, inode, pages,
1274 dirty_pages, pos, copied,
1275 NULL);
1276 if (ret) {
1277 btrfs_delalloc_release_space(inode,
1278 dirty_pages << PAGE_CACHE_SHIFT);
1279 btrfs_drop_pages(pages, num_pages);
1280 break;
1281 }
1282 }
1283
1284 btrfs_drop_pages(pages, num_pages);
1285
1286 cond_resched();
1287
1288 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1289 dirty_pages);
1290 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1291 btrfs_btree_balance_dirty(root, 1);
1292
1293 pos += copied;
1294 num_written += copied;
1295 }
1296
1297 kfree(pages);
1298
1299 return num_written ? num_written : ret;
1300 }
1301
1302 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1303 const struct iovec *iov,
1304 unsigned long nr_segs, loff_t pos,
1305 loff_t *ppos, size_t count, size_t ocount)
1306 {
1307 struct file *file = iocb->ki_filp;
1308 struct inode *inode = fdentry(file)->d_inode;
1309 struct iov_iter i;
1310 ssize_t written;
1311 ssize_t written_buffered;
1312 loff_t endbyte;
1313 int err;
1314
1315 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1316 count, ocount);
1317
1318 /*
1319 * the generic O_DIRECT will update in-memory i_size after the
1320 * DIOs are done. But our endio handlers that update the on
1321 * disk i_size never update past the in memory i_size. So we
1322 * need one more update here to catch any additions to the
1323 * file
1324 */
1325 if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
1326 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
1327 mark_inode_dirty(inode);
1328 }
1329
1330 if (written < 0 || written == count)
1331 return written;
1332
1333 pos += written;
1334 count -= written;
1335 iov_iter_init(&i, iov, nr_segs, count, written);
1336 written_buffered = __btrfs_buffered_write(file, &i, pos);
1337 if (written_buffered < 0) {
1338 err = written_buffered;
1339 goto out;
1340 }
1341 endbyte = pos + written_buffered - 1;
1342 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1343 if (err)
1344 goto out;
1345 written += written_buffered;
1346 *ppos = pos + written_buffered;
1347 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1348 endbyte >> PAGE_CACHE_SHIFT);
1349 out:
1350 return written ? written : err;
1351 }
1352
1353 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1354 const struct iovec *iov,
1355 unsigned long nr_segs, loff_t pos)
1356 {
1357 struct file *file = iocb->ki_filp;
1358 struct inode *inode = fdentry(file)->d_inode;
1359 struct btrfs_root *root = BTRFS_I(inode)->root;
1360 loff_t *ppos = &iocb->ki_pos;
1361 u64 start_pos;
1362 ssize_t num_written = 0;
1363 ssize_t err = 0;
1364 size_t count, ocount;
1365
1366 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1367
1368 mutex_lock(&inode->i_mutex);
1369
1370 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1371 if (err) {
1372 mutex_unlock(&inode->i_mutex);
1373 goto out;
1374 }
1375 count = ocount;
1376
1377 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1378 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1379 if (err) {
1380 mutex_unlock(&inode->i_mutex);
1381 goto out;
1382 }
1383
1384 if (count == 0) {
1385 mutex_unlock(&inode->i_mutex);
1386 goto out;
1387 }
1388
1389 err = file_remove_suid(file);
1390 if (err) {
1391 mutex_unlock(&inode->i_mutex);
1392 goto out;
1393 }
1394
1395 /*
1396 * If BTRFS flips readonly due to some impossible error
1397 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1398 * although we have opened a file as writable, we have
1399 * to stop this write operation to ensure FS consistency.
1400 */
1401 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
1402 mutex_unlock(&inode->i_mutex);
1403 err = -EROFS;
1404 goto out;
1405 }
1406
1407 err = btrfs_update_time(file);
1408 if (err) {
1409 mutex_unlock(&inode->i_mutex);
1410 goto out;
1411 }
1412 BTRFS_I(inode)->sequence++;
1413
1414 start_pos = round_down(pos, root->sectorsize);
1415 if (start_pos > i_size_read(inode)) {
1416 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1417 if (err) {
1418 mutex_unlock(&inode->i_mutex);
1419 goto out;
1420 }
1421 }
1422
1423 if (unlikely(file->f_flags & O_DIRECT)) {
1424 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1425 pos, ppos, count, ocount);
1426 } else {
1427 struct iov_iter i;
1428
1429 iov_iter_init(&i, iov, nr_segs, count, num_written);
1430
1431 num_written = __btrfs_buffered_write(file, &i, pos);
1432 if (num_written > 0)
1433 *ppos = pos + num_written;
1434 }
1435
1436 mutex_unlock(&inode->i_mutex);
1437
1438 /*
1439 * we want to make sure fsync finds this change
1440 * but we haven't joined a transaction running right now.
1441 *
1442 * Later on, someone is sure to update the inode and get the
1443 * real transid recorded.
1444 *
1445 * We set last_trans now to the fs_info generation + 1,
1446 * this will either be one more than the running transaction
1447 * or the generation used for the next transaction if there isn't
1448 * one running right now.
1449 */
1450 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1451 if (num_written > 0 || num_written == -EIOCBQUEUED) {
1452 err = generic_write_sync(file, pos, num_written);
1453 if (err < 0 && num_written > 0)
1454 num_written = err;
1455 }
1456 out:
1457 current->backing_dev_info = NULL;
1458 return num_written ? num_written : err;
1459 }
1460
1461 int btrfs_release_file(struct inode *inode, struct file *filp)
1462 {
1463 /*
1464 * ordered_data_close is set by settattr when we are about to truncate
1465 * a file from a non-zero size to a zero size. This tries to
1466 * flush down new bytes that may have been written if the
1467 * application were using truncate to replace a file in place.
1468 */
1469 if (BTRFS_I(inode)->ordered_data_close) {
1470 BTRFS_I(inode)->ordered_data_close = 0;
1471 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1472 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1473 filemap_flush(inode->i_mapping);
1474 }
1475 if (filp->private_data)
1476 btrfs_ioctl_trans_end(filp);
1477 return 0;
1478 }
1479
1480 /*
1481 * fsync call for both files and directories. This logs the inode into
1482 * the tree log instead of forcing full commits whenever possible.
1483 *
1484 * It needs to call filemap_fdatawait so that all ordered extent updates are
1485 * in the metadata btree are up to date for copying to the log.
1486 *
1487 * It drops the inode mutex before doing the tree log commit. This is an
1488 * important optimization for directories because holding the mutex prevents
1489 * new operations on the dir while we write to disk.
1490 */
1491 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1492 {
1493 struct dentry *dentry = file->f_path.dentry;
1494 struct inode *inode = dentry->d_inode;
1495 struct btrfs_root *root = BTRFS_I(inode)->root;
1496 int ret = 0;
1497 struct btrfs_trans_handle *trans;
1498
1499 trace_btrfs_sync_file(file, datasync);
1500
1501 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
1502 if (ret)
1503 return ret;
1504 mutex_lock(&inode->i_mutex);
1505
1506 /* we wait first, since the writeback may change the inode */
1507 root->log_batch++;
1508 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1509 root->log_batch++;
1510
1511 /*
1512 * check the transaction that last modified this inode
1513 * and see if its already been committed
1514 */
1515 if (!BTRFS_I(inode)->last_trans) {
1516 mutex_unlock(&inode->i_mutex);
1517 goto out;
1518 }
1519
1520 /*
1521 * if the last transaction that changed this file was before
1522 * the current transaction, we can bail out now without any
1523 * syncing
1524 */
1525 smp_mb();
1526 if (BTRFS_I(inode)->last_trans <=
1527 root->fs_info->last_trans_committed) {
1528 BTRFS_I(inode)->last_trans = 0;
1529 mutex_unlock(&inode->i_mutex);
1530 goto out;
1531 }
1532
1533 /*
1534 * ok we haven't committed the transaction yet, lets do a commit
1535 */
1536 if (file->private_data)
1537 btrfs_ioctl_trans_end(file);
1538
1539 trans = btrfs_start_transaction(root, 0);
1540 if (IS_ERR(trans)) {
1541 ret = PTR_ERR(trans);
1542 mutex_unlock(&inode->i_mutex);
1543 goto out;
1544 }
1545
1546 ret = btrfs_log_dentry_safe(trans, root, dentry);
1547 if (ret < 0) {
1548 mutex_unlock(&inode->i_mutex);
1549 goto out;
1550 }
1551
1552 /* we've logged all the items and now have a consistent
1553 * version of the file in the log. It is possible that
1554 * someone will come in and modify the file, but that's
1555 * fine because the log is consistent on disk, and we
1556 * have references to all of the file's extents
1557 *
1558 * It is possible that someone will come in and log the
1559 * file again, but that will end up using the synchronization
1560 * inside btrfs_sync_log to keep things safe.
1561 */
1562 mutex_unlock(&inode->i_mutex);
1563
1564 if (ret != BTRFS_NO_LOG_SYNC) {
1565 if (ret > 0) {
1566 ret = btrfs_commit_transaction(trans, root);
1567 } else {
1568 ret = btrfs_sync_log(trans, root);
1569 if (ret == 0)
1570 ret = btrfs_end_transaction(trans, root);
1571 else
1572 ret = btrfs_commit_transaction(trans, root);
1573 }
1574 } else {
1575 ret = btrfs_end_transaction(trans, root);
1576 }
1577 out:
1578 return ret > 0 ? -EIO : ret;
1579 }
1580
1581 static const struct vm_operations_struct btrfs_file_vm_ops = {
1582 .fault = filemap_fault,
1583 .page_mkwrite = btrfs_page_mkwrite,
1584 };
1585
1586 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1587 {
1588 struct address_space *mapping = filp->f_mapping;
1589
1590 if (!mapping->a_ops->readpage)
1591 return -ENOEXEC;
1592
1593 file_accessed(filp);
1594 vma->vm_ops = &btrfs_file_vm_ops;
1595 vma->vm_flags |= VM_CAN_NONLINEAR;
1596
1597 return 0;
1598 }
1599
1600 static long btrfs_fallocate(struct file *file, int mode,
1601 loff_t offset, loff_t len)
1602 {
1603 struct inode *inode = file->f_path.dentry->d_inode;
1604 struct extent_state *cached_state = NULL;
1605 u64 cur_offset;
1606 u64 last_byte;
1607 u64 alloc_start;
1608 u64 alloc_end;
1609 u64 alloc_hint = 0;
1610 u64 locked_end;
1611 u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1612 struct extent_map *em;
1613 int ret;
1614
1615 alloc_start = offset & ~mask;
1616 alloc_end = (offset + len + mask) & ~mask;
1617
1618 /* We only support the FALLOC_FL_KEEP_SIZE mode */
1619 if (mode & ~FALLOC_FL_KEEP_SIZE)
1620 return -EOPNOTSUPP;
1621
1622 /*
1623 * Make sure we have enough space before we do the
1624 * allocation.
1625 */
1626 ret = btrfs_check_data_free_space(inode, len);
1627 if (ret)
1628 return ret;
1629
1630 /*
1631 * wait for ordered IO before we have any locks. We'll loop again
1632 * below with the locks held.
1633 */
1634 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1635
1636 mutex_lock(&inode->i_mutex);
1637 ret = inode_newsize_ok(inode, alloc_end);
1638 if (ret)
1639 goto out;
1640
1641 if (alloc_start > inode->i_size) {
1642 ret = btrfs_cont_expand(inode, i_size_read(inode),
1643 alloc_start);
1644 if (ret)
1645 goto out;
1646 }
1647
1648 locked_end = alloc_end - 1;
1649 while (1) {
1650 struct btrfs_ordered_extent *ordered;
1651
1652 /* the extent lock is ordered inside the running
1653 * transaction
1654 */
1655 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1656 locked_end, 0, &cached_state);
1657 ordered = btrfs_lookup_first_ordered_extent(inode,
1658 alloc_end - 1);
1659 if (ordered &&
1660 ordered->file_offset + ordered->len > alloc_start &&
1661 ordered->file_offset < alloc_end) {
1662 btrfs_put_ordered_extent(ordered);
1663 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1664 alloc_start, locked_end,
1665 &cached_state, GFP_NOFS);
1666 /*
1667 * we can't wait on the range with the transaction
1668 * running or with the extent lock held
1669 */
1670 btrfs_wait_ordered_range(inode, alloc_start,
1671 alloc_end - alloc_start);
1672 } else {
1673 if (ordered)
1674 btrfs_put_ordered_extent(ordered);
1675 break;
1676 }
1677 }
1678
1679 cur_offset = alloc_start;
1680 while (1) {
1681 u64 actual_end;
1682
1683 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1684 alloc_end - cur_offset, 0);
1685 if (IS_ERR_OR_NULL(em)) {
1686 if (!em)
1687 ret = -ENOMEM;
1688 else
1689 ret = PTR_ERR(em);
1690 break;
1691 }
1692 last_byte = min(extent_map_end(em), alloc_end);
1693 actual_end = min_t(u64, extent_map_end(em), offset + len);
1694 last_byte = (last_byte + mask) & ~mask;
1695
1696 if (em->block_start == EXTENT_MAP_HOLE ||
1697 (cur_offset >= inode->i_size &&
1698 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1699 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1700 last_byte - cur_offset,
1701 1 << inode->i_blkbits,
1702 offset + len,
1703 &alloc_hint);
1704
1705 if (ret < 0) {
1706 free_extent_map(em);
1707 break;
1708 }
1709 } else if (actual_end > inode->i_size &&
1710 !(mode & FALLOC_FL_KEEP_SIZE)) {
1711 /*
1712 * We didn't need to allocate any more space, but we
1713 * still extended the size of the file so we need to
1714 * update i_size.
1715 */
1716 inode->i_ctime = CURRENT_TIME;
1717 i_size_write(inode, actual_end);
1718 btrfs_ordered_update_i_size(inode, actual_end, NULL);
1719 }
1720 free_extent_map(em);
1721
1722 cur_offset = last_byte;
1723 if (cur_offset >= alloc_end) {
1724 ret = 0;
1725 break;
1726 }
1727 }
1728 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1729 &cached_state, GFP_NOFS);
1730 out:
1731 mutex_unlock(&inode->i_mutex);
1732 /* Let go of our reservation. */
1733 btrfs_free_reserved_data_space(inode, len);
1734 return ret;
1735 }
1736
1737 static int find_desired_extent(struct inode *inode, loff_t *offset, int origin)
1738 {
1739 struct btrfs_root *root = BTRFS_I(inode)->root;
1740 struct extent_map *em;
1741 struct extent_state *cached_state = NULL;
1742 u64 lockstart = *offset;
1743 u64 lockend = i_size_read(inode);
1744 u64 start = *offset;
1745 u64 orig_start = *offset;
1746 u64 len = i_size_read(inode);
1747 u64 last_end = 0;
1748 int ret = 0;
1749
1750 lockend = max_t(u64, root->sectorsize, lockend);
1751 if (lockend <= lockstart)
1752 lockend = lockstart + root->sectorsize;
1753
1754 len = lockend - lockstart + 1;
1755
1756 len = max_t(u64, len, root->sectorsize);
1757 if (inode->i_size == 0)
1758 return -ENXIO;
1759
1760 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
1761 &cached_state);
1762
1763 /*
1764 * Delalloc is such a pain. If we have a hole and we have pending
1765 * delalloc for a portion of the hole we will get back a hole that
1766 * exists for the entire range since it hasn't been actually written
1767 * yet. So to take care of this case we need to look for an extent just
1768 * before the position we want in case there is outstanding delalloc
1769 * going on here.
1770 */
1771 if (origin == SEEK_HOLE && start != 0) {
1772 if (start <= root->sectorsize)
1773 em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
1774 root->sectorsize, 0);
1775 else
1776 em = btrfs_get_extent_fiemap(inode, NULL, 0,
1777 start - root->sectorsize,
1778 root->sectorsize, 0);
1779 if (IS_ERR(em)) {
1780 ret = PTR_ERR(em);
1781 goto out;
1782 }
1783 last_end = em->start + em->len;
1784 if (em->block_start == EXTENT_MAP_DELALLOC)
1785 last_end = min_t(u64, last_end, inode->i_size);
1786 free_extent_map(em);
1787 }
1788
1789 while (1) {
1790 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
1791 if (IS_ERR(em)) {
1792 ret = PTR_ERR(em);
1793 break;
1794 }
1795
1796 if (em->block_start == EXTENT_MAP_HOLE) {
1797 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1798 if (last_end <= orig_start) {
1799 free_extent_map(em);
1800 ret = -ENXIO;
1801 break;
1802 }
1803 }
1804
1805 if (origin == SEEK_HOLE) {
1806 *offset = start;
1807 free_extent_map(em);
1808 break;
1809 }
1810 } else {
1811 if (origin == SEEK_DATA) {
1812 if (em->block_start == EXTENT_MAP_DELALLOC) {
1813 if (start >= inode->i_size) {
1814 free_extent_map(em);
1815 ret = -ENXIO;
1816 break;
1817 }
1818 }
1819
1820 *offset = start;
1821 free_extent_map(em);
1822 break;
1823 }
1824 }
1825
1826 start = em->start + em->len;
1827 last_end = em->start + em->len;
1828
1829 if (em->block_start == EXTENT_MAP_DELALLOC)
1830 last_end = min_t(u64, last_end, inode->i_size);
1831
1832 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1833 free_extent_map(em);
1834 ret = -ENXIO;
1835 break;
1836 }
1837 free_extent_map(em);
1838 cond_resched();
1839 }
1840 if (!ret)
1841 *offset = min(*offset, inode->i_size);
1842 out:
1843 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
1844 &cached_state, GFP_NOFS);
1845 return ret;
1846 }
1847
1848 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
1849 {
1850 struct inode *inode = file->f_mapping->host;
1851 int ret;
1852
1853 mutex_lock(&inode->i_mutex);
1854 switch (origin) {
1855 case SEEK_END:
1856 case SEEK_CUR:
1857 offset = generic_file_llseek(file, offset, origin);
1858 goto out;
1859 case SEEK_DATA:
1860 case SEEK_HOLE:
1861 if (offset >= i_size_read(inode)) {
1862 mutex_unlock(&inode->i_mutex);
1863 return -ENXIO;
1864 }
1865
1866 ret = find_desired_extent(inode, &offset, origin);
1867 if (ret) {
1868 mutex_unlock(&inode->i_mutex);
1869 return ret;
1870 }
1871 }
1872
1873 if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
1874 offset = -EINVAL;
1875 goto out;
1876 }
1877 if (offset > inode->i_sb->s_maxbytes) {
1878 offset = -EINVAL;
1879 goto out;
1880 }
1881
1882 /* Special lock needed here? */
1883 if (offset != file->f_pos) {
1884 file->f_pos = offset;
1885 file->f_version = 0;
1886 }
1887 out:
1888 mutex_unlock(&inode->i_mutex);
1889 return offset;
1890 }
1891
1892 const struct file_operations btrfs_file_operations = {
1893 .llseek = btrfs_file_llseek,
1894 .read = do_sync_read,
1895 .write = do_sync_write,
1896 .aio_read = generic_file_aio_read,
1897 .splice_read = generic_file_splice_read,
1898 .aio_write = btrfs_file_aio_write,
1899 .mmap = btrfs_file_mmap,
1900 .open = generic_file_open,
1901 .release = btrfs_release_file,
1902 .fsync = btrfs_sync_file,
1903 .fallocate = btrfs_fallocate,
1904 .unlocked_ioctl = btrfs_ioctl,
1905 #ifdef CONFIG_COMPAT
1906 .compat_ioctl = btrfs_ioctl,
1907 #endif
1908 };
Linux kernel - Deliverables
This page took 0.099696 seconds and 5 git commands to generate.