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nfs41: implement DESTROY_CLIENTID operation
[linux-btrfs-devel.git] / fs / btrfs / file.c
blob658d66959abe9eca7608f650d73bd9952a053ac4
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 spin_unlock(&root->fs_info->defrag_inodes_lock);
154 return 0;
155 }
156
157 /*
158 * must be called with the defrag_inodes lock held
159 */
160 struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info, u64 ino,
161 struct rb_node **next)
162 {
163 struct inode_defrag *entry = NULL;
164 struct rb_node *p;
165 struct rb_node *parent = NULL;
166
167 p = info->defrag_inodes.rb_node;
168 while (p) {
169 parent = p;
170 entry = rb_entry(parent, struct inode_defrag, rb_node);
171
172 if (ino < entry->ino)
173 p = parent->rb_left;
174 else if (ino > entry->ino)
175 p = parent->rb_right;
176 else
177 return entry;
178 }
179
180 if (next) {
181 while (parent && ino > entry->ino) {
182 parent = rb_next(parent);
183 entry = rb_entry(parent, struct inode_defrag, rb_node);
184 }
185 *next = parent;
186 }
187 return NULL;
188 }
189
190 /*
191 * run through the list of inodes in the FS that need
192 * defragging
193 */
194 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
195 {
196 struct inode_defrag *defrag;
197 struct btrfs_root *inode_root;
198 struct inode *inode;
199 struct rb_node *n;
200 struct btrfs_key key;
201 struct btrfs_ioctl_defrag_range_args range;
202 u64 first_ino = 0;
203 int num_defrag;
204 int defrag_batch = 1024;
205
206 memset(&range, 0, sizeof(range));
207 range.len = (u64)-1;
208
209 atomic_inc(&fs_info->defrag_running);
210 spin_lock(&fs_info->defrag_inodes_lock);
211 while(1) {
212 n = NULL;
213
214 /* find an inode to defrag */
215 defrag = btrfs_find_defrag_inode(fs_info, first_ino, &n);
216 if (!defrag) {
217 if (n)
218 defrag = rb_entry(n, struct inode_defrag, rb_node);
219 else if (first_ino) {
220 first_ino = 0;
221 continue;
222 } else {
223 break;
224 }
225 }
226
227 /* remove it from the rbtree */
228 first_ino = defrag->ino + 1;
229 rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
230
231 if (btrfs_fs_closing(fs_info))
232 goto next_free;
233
234 spin_unlock(&fs_info->defrag_inodes_lock);
235
236 /* get the inode */
237 key.objectid = defrag->root;
238 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
239 key.offset = (u64)-1;
240 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
241 if (IS_ERR(inode_root))
242 goto next;
243
244 key.objectid = defrag->ino;
245 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
246 key.offset = 0;
247
248 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
249 if (IS_ERR(inode))
250 goto next;
251
252 /* do a chunk of defrag */
253 BTRFS_I(inode)->in_defrag = 0;
254 range.start = defrag->last_offset;
255 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
256 defrag_batch);
257 /*
258 * if we filled the whole defrag batch, there
259 * must be more work to do. Queue this defrag
260 * again
261 */
262 if (num_defrag == defrag_batch) {
263 defrag->last_offset = range.start;
264 __btrfs_add_inode_defrag(inode, defrag);
265 /*
266 * we don't want to kfree defrag, we added it back to
267 * the rbtree
268 */
269 defrag = NULL;
270 } else if (defrag->last_offset && !defrag->cycled) {
271 /*
272 * we didn't fill our defrag batch, but
273 * we didn't start at zero. Make sure we loop
274 * around to the start of the file.
275 */
276 defrag->last_offset = 0;
277 defrag->cycled = 1;
278 __btrfs_add_inode_defrag(inode, defrag);
279 defrag = NULL;
280 }
281
282 iput(inode);
283 next:
284 spin_lock(&fs_info->defrag_inodes_lock);
285 next_free:
286 kfree(defrag);
287 }
288 spin_unlock(&fs_info->defrag_inodes_lock);
289
290 atomic_dec(&fs_info->defrag_running);
291
292 /*
293 * during unmount, we use the transaction_wait queue to
294 * wait for the defragger to stop
295 */
296 wake_up(&fs_info->transaction_wait);
297 return 0;
298 }
299
300 /* simple helper to fault in pages and copy. This should go away
301 * and be replaced with calls into generic code.
302 */
303 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
304 size_t write_bytes,
305 struct page **prepared_pages,
306 struct iov_iter *i)
307 {
308 size_t copied = 0;
309 size_t total_copied = 0;
310 int pg = 0;
311 int offset = pos & (PAGE_CACHE_SIZE - 1);
312
313 while (write_bytes > 0) {
314 size_t count = min_t(size_t,
315 PAGE_CACHE_SIZE - offset, write_bytes);
316 struct page *page = prepared_pages[pg];
317 /*
318 * Copy data from userspace to the current page
319 *
320 * Disable pagefault to avoid recursive lock since
321 * the pages are already locked
322 */
323 pagefault_disable();
324 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
325 pagefault_enable();
326
327 /* Flush processor's dcache for this page */
328 flush_dcache_page(page);
329
330 /*
331 * if we get a partial write, we can end up with
332 * partially up to date pages. These add
333 * a lot of complexity, so make sure they don't
334 * happen by forcing this copy to be retried.
335 *
336 * The rest of the btrfs_file_write code will fall
337 * back to page at a time copies after we return 0.
338 */
339 if (!PageUptodate(page) && copied < count)
340 copied = 0;
341
342 iov_iter_advance(i, copied);
343 write_bytes -= copied;
344 total_copied += copied;
345
346 /* Return to btrfs_file_aio_write to fault page */
347 if (unlikely(copied == 0))
348 break;
349
350 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
351 offset += copied;
352 } else {
353 pg++;
354 offset = 0;
355 }
356 }
357 return total_copied;
358 }
359
360 /*
361 * unlocks pages after btrfs_file_write is done with them
362 */
363 void btrfs_drop_pages(struct page **pages, size_t num_pages)
364 {
365 size_t i;
366 for (i = 0; i < num_pages; i++) {
367 /* page checked is some magic around finding pages that
368 * have been modified without going through btrfs_set_page_dirty
369 * clear it here
370 */
371 ClearPageChecked(pages[i]);
372 unlock_page(pages[i]);
373 mark_page_accessed(pages[i]);
374 page_cache_release(pages[i]);
375 }
376 }
377
378 /*
379 * after copy_from_user, pages need to be dirtied and we need to make
380 * sure holes are created between the current EOF and the start of
381 * any next extents (if required).
382 *
383 * this also makes the decision about creating an inline extent vs
384 * doing real data extents, marking pages dirty and delalloc as required.
385 */
386 int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
387 struct page **pages, size_t num_pages,
388 loff_t pos, size_t write_bytes,
389 struct extent_state **cached)
390 {
391 int err = 0;
392 int i;
393 u64 num_bytes;
394 u64 start_pos;
395 u64 end_of_last_block;
396 u64 end_pos = pos + write_bytes;
397 loff_t isize = i_size_read(inode);
398
399 start_pos = pos & ~((u64)root->sectorsize - 1);
400 num_bytes = (write_bytes + pos - start_pos +
401 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
402
403 end_of_last_block = start_pos + num_bytes - 1;
404 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
405 cached);
406 if (err)
407 return err;
408
409 for (i = 0; i < num_pages; i++) {
410 struct page *p = pages[i];
411 SetPageUptodate(p);
412 ClearPageChecked(p);
413 set_page_dirty(p);
414 }
415
416 /*
417 * we've only changed i_size in ram, and we haven't updated
418 * the disk i_size. There is no need to log the inode
419 * at this time.
420 */
421 if (end_pos > isize)
422 i_size_write(inode, end_pos);
423 return 0;
424 }
425
426 /*
427 * this drops all the extents in the cache that intersect the range
428 * [start, end]. Existing extents are split as required.
429 */
430 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
431 int skip_pinned)
432 {
433 struct extent_map *em;
434 struct extent_map *split = NULL;
435 struct extent_map *split2 = NULL;
436 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
437 u64 len = end - start + 1;
438 int ret;
439 int testend = 1;
440 unsigned long flags;
441 int compressed = 0;
442
443 WARN_ON(end < start);
444 if (end == (u64)-1) {
445 len = (u64)-1;
446 testend = 0;
447 }
448 while (1) {
449 if (!split)
450 split = alloc_extent_map();
451 if (!split2)
452 split2 = alloc_extent_map();
453 BUG_ON(!split || !split2);
454
455 write_lock(&em_tree->lock);
456 em = lookup_extent_mapping(em_tree, start, len);
457 if (!em) {
458 write_unlock(&em_tree->lock);
459 break;
460 }
461 flags = em->flags;
462 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
463 if (testend && em->start + em->len >= start + len) {
464 free_extent_map(em);
465 write_unlock(&em_tree->lock);
466 break;
467 }
468 start = em->start + em->len;
469 if (testend)
470 len = start + len - (em->start + em->len);
471 free_extent_map(em);
472 write_unlock(&em_tree->lock);
473 continue;
474 }
475 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
476 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
477 remove_extent_mapping(em_tree, em);
478
479 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
480 em->start < start) {
481 split->start = em->start;
482 split->len = start - em->start;
483 split->orig_start = em->orig_start;
484 split->block_start = em->block_start;
485
486 if (compressed)
487 split->block_len = em->block_len;
488 else
489 split->block_len = split->len;
490
491 split->bdev = em->bdev;
492 split->flags = flags;
493 split->compress_type = em->compress_type;
494 ret = add_extent_mapping(em_tree, split);
495 BUG_ON(ret);
496 free_extent_map(split);
497 split = split2;
498 split2 = NULL;
499 }
500 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
501 testend && em->start + em->len > start + len) {
502 u64 diff = start + len - em->start;
503
504 split->start = start + len;
505 split->len = em->start + em->len - (start + len);
506 split->bdev = em->bdev;
507 split->flags = flags;
508 split->compress_type = em->compress_type;
509
510 if (compressed) {
511 split->block_len = em->block_len;
512 split->block_start = em->block_start;
513 split->orig_start = em->orig_start;
514 } else {
515 split->block_len = split->len;
516 split->block_start = em->block_start + diff;
517 split->orig_start = split->start;
518 }
519
520 ret = add_extent_mapping(em_tree, split);
521 BUG_ON(ret);
522 free_extent_map(split);
523 split = NULL;
524 }
525 write_unlock(&em_tree->lock);
526
527 /* once for us */
528 free_extent_map(em);
529 /* once for the tree*/
530 free_extent_map(em);
531 }
532 if (split)
533 free_extent_map(split);
534 if (split2)
535 free_extent_map(split2);
536 return 0;
537 }
538
539 /*
540 * this is very complex, but the basic idea is to drop all extents
541 * in the range start - end. hint_block is filled in with a block number
542 * that would be a good hint to the block allocator for this file.
543 *
544 * If an extent intersects the range but is not entirely inside the range
545 * it is either truncated or split. Anything entirely inside the range
546 * is deleted from the tree.
547 */
548 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
549 u64 start, u64 end, u64 *hint_byte, int drop_cache)
550 {
551 struct btrfs_root *root = BTRFS_I(inode)->root;
552 struct extent_buffer *leaf;
553 struct btrfs_file_extent_item *fi;
554 struct btrfs_path *path;
555 struct btrfs_key key;
556 struct btrfs_key new_key;
557 u64 ino = btrfs_ino(inode);
558 u64 search_start = start;
559 u64 disk_bytenr = 0;
560 u64 num_bytes = 0;
561 u64 extent_offset = 0;
562 u64 extent_end = 0;
563 int del_nr = 0;
564 int del_slot = 0;
565 int extent_type;
566 int recow;
567 int ret;
568
569 if (drop_cache)
570 btrfs_drop_extent_cache(inode, start, end - 1, 0);
571
572 path = btrfs_alloc_path();
573 if (!path)
574 return -ENOMEM;
575
576 while (1) {
577 recow = 0;
578 ret = btrfs_lookup_file_extent(trans, root, path, ino,
579 search_start, -1);
580 if (ret < 0)
581 break;
582 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
583 leaf = path->nodes[0];
584 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
585 if (key.objectid == ino &&
586 key.type == BTRFS_EXTENT_DATA_KEY)
587 path->slots[0]--;
588 }
589 ret = 0;
590 next_slot:
591 leaf = path->nodes[0];
592 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
593 BUG_ON(del_nr > 0);
594 ret = btrfs_next_leaf(root, path);
595 if (ret < 0)
596 break;
597 if (ret > 0) {
598 ret = 0;
599 break;
600 }
601 leaf = path->nodes[0];
602 recow = 1;
603 }
604
605 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
606 if (key.objectid > ino ||
607 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
608 break;
609
610 fi = btrfs_item_ptr(leaf, path->slots[0],
611 struct btrfs_file_extent_item);
612 extent_type = btrfs_file_extent_type(leaf, fi);
613
614 if (extent_type == BTRFS_FILE_EXTENT_REG ||
615 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
616 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
617 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
618 extent_offset = btrfs_file_extent_offset(leaf, fi);
619 extent_end = key.offset +
620 btrfs_file_extent_num_bytes(leaf, fi);
621 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
622 extent_end = key.offset +
623 btrfs_file_extent_inline_len(leaf, fi);
624 } else {
625 WARN_ON(1);
626 extent_end = search_start;
627 }
628
629 if (extent_end <= search_start) {
630 path->slots[0]++;
631 goto next_slot;
632 }
633
634 search_start = max(key.offset, start);
635 if (recow) {
636 btrfs_release_path(path);
637 continue;
638 }
639
640 /*
641 * | - range to drop - |
642 * | -------- extent -------- |
643 */
644 if (start > key.offset && end < extent_end) {
645 BUG_ON(del_nr > 0);
646 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
647
648 memcpy(&new_key, &key, sizeof(new_key));
649 new_key.offset = start;
650 ret = btrfs_duplicate_item(trans, root, path,
651 &new_key);
652 if (ret == -EAGAIN) {
653 btrfs_release_path(path);
654 continue;
655 }
656 if (ret < 0)
657 break;
658
659 leaf = path->nodes[0];
660 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
661 struct btrfs_file_extent_item);
662 btrfs_set_file_extent_num_bytes(leaf, fi,
663 start - key.offset);
664
665 fi = btrfs_item_ptr(leaf, path->slots[0],
666 struct btrfs_file_extent_item);
667
668 extent_offset += start - key.offset;
669 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
670 btrfs_set_file_extent_num_bytes(leaf, fi,
671 extent_end - start);
672 btrfs_mark_buffer_dirty(leaf);
673
674 if (disk_bytenr > 0) {
675 ret = btrfs_inc_extent_ref(trans, root,
676 disk_bytenr, num_bytes, 0,
677 root->root_key.objectid,
678 new_key.objectid,
679 start - extent_offset);
680 BUG_ON(ret);
681 *hint_byte = disk_bytenr;
682 }
683 key.offset = start;
684 }
685 /*
686 * | ---- range to drop ----- |
687 * | -------- extent -------- |
688 */
689 if (start <= key.offset && end < extent_end) {
690 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
691
692 memcpy(&new_key, &key, sizeof(new_key));
693 new_key.offset = end;
694 btrfs_set_item_key_safe(trans, root, path, &new_key);
695
696 extent_offset += end - key.offset;
697 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
698 btrfs_set_file_extent_num_bytes(leaf, fi,
699 extent_end - end);
700 btrfs_mark_buffer_dirty(leaf);
701 if (disk_bytenr > 0) {
702 inode_sub_bytes(inode, end - key.offset);
703 *hint_byte = disk_bytenr;
704 }
705 break;
706 }
707
708 search_start = extent_end;
709 /*
710 * | ---- range to drop ----- |
711 * | -------- extent -------- |
712 */
713 if (start > key.offset && end >= extent_end) {
714 BUG_ON(del_nr > 0);
715 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
716
717 btrfs_set_file_extent_num_bytes(leaf, fi,
718 start - key.offset);
719 btrfs_mark_buffer_dirty(leaf);
720 if (disk_bytenr > 0) {
721 inode_sub_bytes(inode, extent_end - start);
722 *hint_byte = disk_bytenr;
723 }
724 if (end == extent_end)
725 break;
726
727 path->slots[0]++;
728 goto next_slot;
729 }
730
731 /*
732 * | ---- range to drop ----- |
733 * | ------ extent ------ |
734 */
735 if (start <= key.offset && end >= extent_end) {
736 if (del_nr == 0) {
737 del_slot = path->slots[0];
738 del_nr = 1;
739 } else {
740 BUG_ON(del_slot + del_nr != path->slots[0]);
741 del_nr++;
742 }
743
744 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
745 inode_sub_bytes(inode,
746 extent_end - key.offset);
747 extent_end = ALIGN(extent_end,
748 root->sectorsize);
749 } else if (disk_bytenr > 0) {
750 ret = btrfs_free_extent(trans, root,
751 disk_bytenr, num_bytes, 0,
752 root->root_key.objectid,
753 key.objectid, key.offset -
754 extent_offset);
755 BUG_ON(ret);
756 inode_sub_bytes(inode,
757 extent_end - key.offset);
758 *hint_byte = disk_bytenr;
759 }
760
761 if (end == extent_end)
762 break;
763
764 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
765 path->slots[0]++;
766 goto next_slot;
767 }
768
769 ret = btrfs_del_items(trans, root, path, del_slot,
770 del_nr);
771 BUG_ON(ret);
772
773 del_nr = 0;
774 del_slot = 0;
775
776 btrfs_release_path(path);
777 continue;
778 }
779
780 BUG_ON(1);
781 }
782
783 if (del_nr > 0) {
784 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
785 BUG_ON(ret);
786 }
787
788 btrfs_free_path(path);
789 return ret;
790 }
791
792 static int extent_mergeable(struct extent_buffer *leaf, int slot,
793 u64 objectid, u64 bytenr, u64 orig_offset,
794 u64 *start, u64 *end)
795 {
796 struct btrfs_file_extent_item *fi;
797 struct btrfs_key key;
798 u64 extent_end;
799
800 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
801 return 0;
802
803 btrfs_item_key_to_cpu(leaf, &key, slot);
804 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
805 return 0;
806
807 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
808 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
809 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
810 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
811 btrfs_file_extent_compression(leaf, fi) ||
812 btrfs_file_extent_encryption(leaf, fi) ||
813 btrfs_file_extent_other_encoding(leaf, fi))
814 return 0;
815
816 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
817 if ((*start && *start != key.offset) || (*end && *end != extent_end))
818 return 0;
819
820 *start = key.offset;
821 *end = extent_end;
822 return 1;
823 }
824
825 /*
826 * Mark extent in the range start - end as written.
827 *
828 * This changes extent type from 'pre-allocated' to 'regular'. If only
829 * part of extent is marked as written, the extent will be split into
830 * two or three.
831 */
832 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
833 struct inode *inode, u64 start, u64 end)
834 {
835 struct btrfs_root *root = BTRFS_I(inode)->root;
836 struct extent_buffer *leaf;
837 struct btrfs_path *path;
838 struct btrfs_file_extent_item *fi;
839 struct btrfs_key key;
840 struct btrfs_key new_key;
841 u64 bytenr;
842 u64 num_bytes;
843 u64 extent_end;
844 u64 orig_offset;
845 u64 other_start;
846 u64 other_end;
847 u64 split;
848 int del_nr = 0;
849 int del_slot = 0;
850 int recow;
851 int ret;
852 u64 ino = btrfs_ino(inode);
853
854 btrfs_drop_extent_cache(inode, start, end - 1, 0);
855
856 path = btrfs_alloc_path();
857 if (!path)
858 return -ENOMEM;
859 again:
860 recow = 0;
861 split = start;
862 key.objectid = ino;
863 key.type = BTRFS_EXTENT_DATA_KEY;
864 key.offset = split;
865
866 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
867 if (ret < 0)
868 goto out;
869 if (ret > 0 && path->slots[0] > 0)
870 path->slots[0]--;
871
872 leaf = path->nodes[0];
873 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
874 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
875 fi = btrfs_item_ptr(leaf, path->slots[0],
876 struct btrfs_file_extent_item);
877 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
878 BTRFS_FILE_EXTENT_PREALLOC);
879 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
880 BUG_ON(key.offset > start || extent_end < end);
881
882 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
883 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
884 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
885 memcpy(&new_key, &key, sizeof(new_key));
886
887 if (start == key.offset && end < extent_end) {
888 other_start = 0;
889 other_end = start;
890 if (extent_mergeable(leaf, path->slots[0] - 1,
891 ino, bytenr, orig_offset,
892 &other_start, &other_end)) {
893 new_key.offset = end;
894 btrfs_set_item_key_safe(trans, root, path, &new_key);
895 fi = btrfs_item_ptr(leaf, path->slots[0],
896 struct btrfs_file_extent_item);
897 btrfs_set_file_extent_num_bytes(leaf, fi,
898 extent_end - end);
899 btrfs_set_file_extent_offset(leaf, fi,
900 end - orig_offset);
901 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
902 struct btrfs_file_extent_item);
903 btrfs_set_file_extent_num_bytes(leaf, fi,
904 end - other_start);
905 btrfs_mark_buffer_dirty(leaf);
906 goto out;
907 }
908 }
909
910 if (start > key.offset && end == extent_end) {
911 other_start = end;
912 other_end = 0;
913 if (extent_mergeable(leaf, path->slots[0] + 1,
914 ino, bytenr, orig_offset,
915 &other_start, &other_end)) {
916 fi = btrfs_item_ptr(leaf, path->slots[0],
917 struct btrfs_file_extent_item);
918 btrfs_set_file_extent_num_bytes(leaf, fi,
919 start - key.offset);
920 path->slots[0]++;
921 new_key.offset = start;
922 btrfs_set_item_key_safe(trans, root, path, &new_key);
923
924 fi = btrfs_item_ptr(leaf, path->slots[0],
925 struct btrfs_file_extent_item);
926 btrfs_set_file_extent_num_bytes(leaf, fi,
927 other_end - start);
928 btrfs_set_file_extent_offset(leaf, fi,
929 start - orig_offset);
930 btrfs_mark_buffer_dirty(leaf);
931 goto out;
932 }
933 }
934
935 while (start > key.offset || end < extent_end) {
936 if (key.offset == start)
937 split = end;
938
939 new_key.offset = split;
940 ret = btrfs_duplicate_item(trans, root, path, &new_key);
941 if (ret == -EAGAIN) {
942 btrfs_release_path(path);
943 goto again;
944 }
945 BUG_ON(ret < 0);
946
947 leaf = path->nodes[0];
948 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
949 struct btrfs_file_extent_item);
950 btrfs_set_file_extent_num_bytes(leaf, fi,
951 split - key.offset);
952
953 fi = btrfs_item_ptr(leaf, path->slots[0],
954 struct btrfs_file_extent_item);
955
956 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
957 btrfs_set_file_extent_num_bytes(leaf, fi,
958 extent_end - split);
959 btrfs_mark_buffer_dirty(leaf);
960
961 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
962 root->root_key.objectid,
963 ino, orig_offset);
964 BUG_ON(ret);
965
966 if (split == start) {
967 key.offset = start;
968 } else {
969 BUG_ON(start != key.offset);
970 path->slots[0]--;
971 extent_end = end;
972 }
973 recow = 1;
974 }
975
976 other_start = end;
977 other_end = 0;
978 if (extent_mergeable(leaf, path->slots[0] + 1,
979 ino, bytenr, orig_offset,
980 &other_start, &other_end)) {
981 if (recow) {
982 btrfs_release_path(path);
983 goto again;
984 }
985 extent_end = other_end;
986 del_slot = path->slots[0] + 1;
987 del_nr++;
988 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
989 0, root->root_key.objectid,
990 ino, orig_offset);
991 BUG_ON(ret);
992 }
993 other_start = 0;
994 other_end = start;
995 if (extent_mergeable(leaf, path->slots[0] - 1,
996 ino, bytenr, orig_offset,
997 &other_start, &other_end)) {
998 if (recow) {
999 btrfs_release_path(path);
1000 goto again;
1001 }
1002 key.offset = other_start;
1003 del_slot = path->slots[0];
1004 del_nr++;
1005 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1006 0, root->root_key.objectid,
1007 ino, orig_offset);
1008 BUG_ON(ret);
1009 }
1010 if (del_nr == 0) {
1011 fi = btrfs_item_ptr(leaf, path->slots[0],
1012 struct btrfs_file_extent_item);
1013 btrfs_set_file_extent_type(leaf, fi,
1014 BTRFS_FILE_EXTENT_REG);
1015 btrfs_mark_buffer_dirty(leaf);
1016 } else {
1017 fi = btrfs_item_ptr(leaf, del_slot - 1,
1018 struct btrfs_file_extent_item);
1019 btrfs_set_file_extent_type(leaf, fi,
1020 BTRFS_FILE_EXTENT_REG);
1021 btrfs_set_file_extent_num_bytes(leaf, fi,
1022 extent_end - key.offset);
1023 btrfs_mark_buffer_dirty(leaf);
1024
1025 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1026 BUG_ON(ret);
1027 }
1028 out:
1029 btrfs_free_path(path);
1030 return 0;
1031 }
1032
1033 /*
1034 * on error we return an unlocked page and the error value
1035 * on success we return a locked page and 0
1036 */
1037 static int prepare_uptodate_page(struct page *page, u64 pos)
1038 {
1039 int ret = 0;
1040
1041 if ((pos & (PAGE_CACHE_SIZE - 1)) && !PageUptodate(page)) {
1042 ret = btrfs_readpage(NULL, page);
1043 if (ret)
1044 return ret;
1045 lock_page(page);
1046 if (!PageUptodate(page)) {
1047 unlock_page(page);
1048 return -EIO;
1049 }
1050 }
1051 return 0;
1052 }
1053
1054 /*
1055 * this gets pages into the page cache and locks them down, it also properly
1056 * waits for data=ordered extents to finish before allowing the pages to be
1057 * modified.
1058 */
1059 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1060 struct page **pages, size_t num_pages,
1061 loff_t pos, unsigned long first_index,
1062 size_t write_bytes)
1063 {
1064 struct extent_state *cached_state = NULL;
1065 int i;
1066 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1067 struct inode *inode = fdentry(file)->d_inode;
1068 int err = 0;
1069 int faili = 0;
1070 u64 start_pos;
1071 u64 last_pos;
1072
1073 start_pos = pos & ~((u64)root->sectorsize - 1);
1074 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1075
1076 if (start_pos > inode->i_size) {
1077 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1078 if (err)
1079 return err;
1080 }
1081
1082 again:
1083 for (i = 0; i < num_pages; i++) {
1084 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1085 GFP_NOFS);
1086 if (!pages[i]) {
1087 faili = i - 1;
1088 err = -ENOMEM;
1089 goto fail;
1090 }
1091
1092 if (i == 0)
1093 err = prepare_uptodate_page(pages[i], pos);
1094 if (i == num_pages - 1)
1095 err = prepare_uptodate_page(pages[i],
1096 pos + write_bytes);
1097 if (err) {
1098 page_cache_release(pages[i]);
1099 faili = i - 1;
1100 goto fail;
1101 }
1102 wait_on_page_writeback(pages[i]);
1103 }
1104 err = 0;
1105 if (start_pos < inode->i_size) {
1106 struct btrfs_ordered_extent *ordered;
1107 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1108 start_pos, last_pos - 1, 0, &cached_state,
1109 GFP_NOFS);
1110 ordered = btrfs_lookup_first_ordered_extent(inode,
1111 last_pos - 1);
1112 if (ordered &&
1113 ordered->file_offset + ordered->len > start_pos &&
1114 ordered->file_offset < last_pos) {
1115 btrfs_put_ordered_extent(ordered);
1116 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1117 start_pos, last_pos - 1,
1118 &cached_state, GFP_NOFS);
1119 for (i = 0; i < num_pages; i++) {
1120 unlock_page(pages[i]);
1121 page_cache_release(pages[i]);
1122 }
1123 btrfs_wait_ordered_range(inode, start_pos,
1124 last_pos - start_pos);
1125 goto again;
1126 }
1127 if (ordered)
1128 btrfs_put_ordered_extent(ordered);
1129
1130 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1131 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1132 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
1133 GFP_NOFS);
1134 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1135 start_pos, last_pos - 1, &cached_state,
1136 GFP_NOFS);
1137 }
1138 for (i = 0; i < num_pages; i++) {
1139 clear_page_dirty_for_io(pages[i]);
1140 set_page_extent_mapped(pages[i]);
1141 WARN_ON(!PageLocked(pages[i]));
1142 }
1143 return 0;
1144 fail:
1145 while (faili >= 0) {
1146 unlock_page(pages[faili]);
1147 page_cache_release(pages[faili]);
1148 faili--;
1149 }
1150 return err;
1151
1152 }
1153
1154 static noinline ssize_t __btrfs_buffered_write(struct file *file,
1155 struct iov_iter *i,
1156 loff_t pos)
1157 {
1158 struct inode *inode = fdentry(file)->d_inode;
1159 struct btrfs_root *root = BTRFS_I(inode)->root;
1160 struct page **pages = NULL;
1161 unsigned long first_index;
1162 size_t num_written = 0;
1163 int nrptrs;
1164 int ret = 0;
1165
1166 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1167 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1168 (sizeof(struct page *)));
1169 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1170 if (!pages)
1171 return -ENOMEM;
1172
1173 first_index = pos >> PAGE_CACHE_SHIFT;
1174
1175 while (iov_iter_count(i) > 0) {
1176 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1177 size_t write_bytes = min(iov_iter_count(i),
1178 nrptrs * (size_t)PAGE_CACHE_SIZE -
1179 offset);
1180 size_t num_pages = (write_bytes + offset +
1181 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1182 size_t dirty_pages;
1183 size_t copied;
1184
1185 WARN_ON(num_pages > nrptrs);
1186
1187 /*
1188 * Fault pages before locking them in prepare_pages
1189 * to avoid recursive lock
1190 */
1191 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1192 ret = -EFAULT;
1193 break;
1194 }
1195
1196 ret = btrfs_delalloc_reserve_space(inode,
1197 num_pages << PAGE_CACHE_SHIFT);
1198 if (ret)
1199 break;
1200
1201 /*
1202 * This is going to setup the pages array with the number of
1203 * pages we want, so we don't really need to worry about the
1204 * contents of pages from loop to loop
1205 */
1206 ret = prepare_pages(root, file, pages, num_pages,
1207 pos, first_index, write_bytes);
1208 if (ret) {
1209 btrfs_delalloc_release_space(inode,
1210 num_pages << PAGE_CACHE_SHIFT);
1211 break;
1212 }
1213
1214 copied = btrfs_copy_from_user(pos, num_pages,
1215 write_bytes, pages, i);
1216
1217 /*
1218 * if we have trouble faulting in the pages, fall
1219 * back to one page at a time
1220 */
1221 if (copied < write_bytes)
1222 nrptrs = 1;
1223
1224 if (copied == 0)
1225 dirty_pages = 0;
1226 else
1227 dirty_pages = (copied + offset +
1228 PAGE_CACHE_SIZE - 1) >>
1229 PAGE_CACHE_SHIFT;
1230
1231 /*
1232 * If we had a short copy we need to release the excess delaloc
1233 * bytes we reserved. We need to increment outstanding_extents
1234 * because btrfs_delalloc_release_space will decrement it, but
1235 * we still have an outstanding extent for the chunk we actually
1236 * managed to copy.
1237 */
1238 if (num_pages > dirty_pages) {
1239 if (copied > 0) {
1240 spin_lock(&BTRFS_I(inode)->lock);
1241 BTRFS_I(inode)->outstanding_extents++;
1242 spin_unlock(&BTRFS_I(inode)->lock);
1243 }
1244 btrfs_delalloc_release_space(inode,
1245 (num_pages - dirty_pages) <<
1246 PAGE_CACHE_SHIFT);
1247 }
1248
1249 if (copied > 0) {
1250 ret = btrfs_dirty_pages(root, inode, pages,
1251 dirty_pages, pos, copied,
1252 NULL);
1253 if (ret) {
1254 btrfs_delalloc_release_space(inode,
1255 dirty_pages << PAGE_CACHE_SHIFT);
1256 btrfs_drop_pages(pages, num_pages);
1257 break;
1258 }
1259 }
1260
1261 btrfs_drop_pages(pages, num_pages);
1262
1263 cond_resched();
1264
1265 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1266 dirty_pages);
1267 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1268 btrfs_btree_balance_dirty(root, 1);
1269 btrfs_throttle(root);
1270
1271 pos += copied;
1272 num_written += copied;
1273 }
1274
1275 kfree(pages);
1276
1277 return num_written ? num_written : ret;
1278 }
1279
1280 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1281 const struct iovec *iov,
1282 unsigned long nr_segs, loff_t pos,
1283 loff_t *ppos, size_t count, size_t ocount)
1284 {
1285 struct file *file = iocb->ki_filp;
1286 struct inode *inode = fdentry(file)->d_inode;
1287 struct iov_iter i;
1288 ssize_t written;
1289 ssize_t written_buffered;
1290 loff_t endbyte;
1291 int err;
1292
1293 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1294 count, ocount);
1295
1296 /*
1297 * the generic O_DIRECT will update in-memory i_size after the
1298 * DIOs are done. But our endio handlers that update the on
1299 * disk i_size never update past the in memory i_size. So we
1300 * need one more update here to catch any additions to the
1301 * file
1302 */
1303 if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
1304 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
1305 mark_inode_dirty(inode);
1306 }
1307
1308 if (written < 0 || written == count)
1309 return written;
1310
1311 pos += written;
1312 count -= written;
1313 iov_iter_init(&i, iov, nr_segs, count, written);
1314 written_buffered = __btrfs_buffered_write(file, &i, pos);
1315 if (written_buffered < 0) {
1316 err = written_buffered;
1317 goto out;
1318 }
1319 endbyte = pos + written_buffered - 1;
1320 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1321 if (err)
1322 goto out;
1323 written += written_buffered;
1324 *ppos = pos + written_buffered;
1325 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1326 endbyte >> PAGE_CACHE_SHIFT);
1327 out:
1328 return written ? written : err;
1329 }
1330
1331 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1332 const struct iovec *iov,
1333 unsigned long nr_segs, loff_t pos)
1334 {
1335 struct file *file = iocb->ki_filp;
1336 struct inode *inode = fdentry(file)->d_inode;
1337 struct btrfs_root *root = BTRFS_I(inode)->root;
1338 loff_t *ppos = &iocb->ki_pos;
1339 ssize_t num_written = 0;
1340 ssize_t err = 0;
1341 size_t count, ocount;
1342
1343 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1344
1345 mutex_lock(&inode->i_mutex);
1346
1347 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1348 if (err) {
1349 mutex_unlock(&inode->i_mutex);
1350 goto out;
1351 }
1352 count = ocount;
1353
1354 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1355 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1356 if (err) {
1357 mutex_unlock(&inode->i_mutex);
1358 goto out;
1359 }
1360
1361 if (count == 0) {
1362 mutex_unlock(&inode->i_mutex);
1363 goto out;
1364 }
1365
1366 err = file_remove_suid(file);
1367 if (err) {
1368 mutex_unlock(&inode->i_mutex);
1369 goto out;
1370 }
1371
1372 /*
1373 * If BTRFS flips readonly due to some impossible error
1374 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1375 * although we have opened a file as writable, we have
1376 * to stop this write operation to ensure FS consistency.
1377 */
1378 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
1379 mutex_unlock(&inode->i_mutex);
1380 err = -EROFS;
1381 goto out;
1382 }
1383
1384 file_update_time(file);
1385 BTRFS_I(inode)->sequence++;
1386
1387 if (unlikely(file->f_flags & O_DIRECT)) {
1388 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1389 pos, ppos, count, ocount);
1390 } else {
1391 struct iov_iter i;
1392
1393 iov_iter_init(&i, iov, nr_segs, count, num_written);
1394
1395 num_written = __btrfs_buffered_write(file, &i, pos);
1396 if (num_written > 0)
1397 *ppos = pos + num_written;
1398 }
1399
1400 mutex_unlock(&inode->i_mutex);
1401
1402 /*
1403 * we want to make sure fsync finds this change
1404 * but we haven't joined a transaction running right now.
1405 *
1406 * Later on, someone is sure to update the inode and get the
1407 * real transid recorded.
1408 *
1409 * We set last_trans now to the fs_info generation + 1,
1410 * this will either be one more than the running transaction
1411 * or the generation used for the next transaction if there isn't
1412 * one running right now.
1413 */
1414 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1415 if (num_written > 0 || num_written == -EIOCBQUEUED) {
1416 err = generic_write_sync(file, pos, num_written);
1417 if (err < 0 && num_written > 0)
1418 num_written = err;
1419 }
1420 out:
1421 current->backing_dev_info = NULL;
1422 return num_written ? num_written : err;
1423 }
1424
1425 int btrfs_release_file(struct inode *inode, struct file *filp)
1426 {
1427 /*
1428 * ordered_data_close is set by settattr when we are about to truncate
1429 * a file from a non-zero size to a zero size. This tries to
1430 * flush down new bytes that may have been written if the
1431 * application were using truncate to replace a file in place.
1432 */
1433 if (BTRFS_I(inode)->ordered_data_close) {
1434 BTRFS_I(inode)->ordered_data_close = 0;
1435 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1436 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1437 filemap_flush(inode->i_mapping);
1438 }
1439 if (filp->private_data)
1440 btrfs_ioctl_trans_end(filp);
1441 return 0;
1442 }
1443
1444 /*
1445 * fsync call for both files and directories. This logs the inode into
1446 * the tree log instead of forcing full commits whenever possible.
1447 *
1448 * It needs to call filemap_fdatawait so that all ordered extent updates are
1449 * in the metadata btree are up to date for copying to the log.
1450 *
1451 * It drops the inode mutex before doing the tree log commit. This is an
1452 * important optimization for directories because holding the mutex prevents
1453 * new operations on the dir while we write to disk.
1454 */
1455 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1456 {
1457 struct dentry *dentry = file->f_path.dentry;
1458 struct inode *inode = dentry->d_inode;
1459 struct btrfs_root *root = BTRFS_I(inode)->root;
1460 int ret = 0;
1461 struct btrfs_trans_handle *trans;
1462
1463 trace_btrfs_sync_file(file, datasync);
1464
1465 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
1466 if (ret)
1467 return ret;
1468 mutex_lock(&inode->i_mutex);
1469
1470 /* we wait first, since the writeback may change the inode */
1471 root->log_batch++;
1472 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1473 root->log_batch++;
1474
1475 /*
1476 * check the transaction that last modified this inode
1477 * and see if its already been committed
1478 */
1479 if (!BTRFS_I(inode)->last_trans) {
1480 mutex_unlock(&inode->i_mutex);
1481 goto out;
1482 }
1483
1484 /*
1485 * if the last transaction that changed this file was before
1486 * the current transaction, we can bail out now without any
1487 * syncing
1488 */
1489 smp_mb();
1490 if (BTRFS_I(inode)->last_trans <=
1491 root->fs_info->last_trans_committed) {
1492 BTRFS_I(inode)->last_trans = 0;
1493 mutex_unlock(&inode->i_mutex);
1494 goto out;
1495 }
1496
1497 /*
1498 * ok we haven't committed the transaction yet, lets do a commit
1499 */
1500 if (file->private_data)
1501 btrfs_ioctl_trans_end(file);
1502
1503 trans = btrfs_start_transaction(root, 0);
1504 if (IS_ERR(trans)) {
1505 ret = PTR_ERR(trans);
1506 mutex_unlock(&inode->i_mutex);
1507 goto out;
1508 }
1509
1510 ret = btrfs_log_dentry_safe(trans, root, dentry);
1511 if (ret < 0) {
1512 mutex_unlock(&inode->i_mutex);
1513 goto out;
1514 }
1515
1516 /* we've logged all the items and now have a consistent
1517 * version of the file in the log. It is possible that
1518 * someone will come in and modify the file, but that's
1519 * fine because the log is consistent on disk, and we
1520 * have references to all of the file's extents
1521 *
1522 * It is possible that someone will come in and log the
1523 * file again, but that will end up using the synchronization
1524 * inside btrfs_sync_log to keep things safe.
1525 */
1526 mutex_unlock(&inode->i_mutex);
1527
1528 if (ret != BTRFS_NO_LOG_SYNC) {
1529 if (ret > 0) {
1530 ret = btrfs_commit_transaction(trans, root);
1531 } else {
1532 ret = btrfs_sync_log(trans, root);
1533 if (ret == 0)
1534 ret = btrfs_end_transaction(trans, root);
1535 else
1536 ret = btrfs_commit_transaction(trans, root);
1537 }
1538 } else {
1539 ret = btrfs_end_transaction(trans, root);
1540 }
1541 out:
1542 return ret > 0 ? -EIO : ret;
1543 }
1544
1545 static const struct vm_operations_struct btrfs_file_vm_ops = {
1546 .fault = filemap_fault,
1547 .page_mkwrite = btrfs_page_mkwrite,
1548 };
1549
1550 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1551 {
1552 struct address_space *mapping = filp->f_mapping;
1553
1554 if (!mapping->a_ops->readpage)
1555 return -ENOEXEC;
1556
1557 file_accessed(filp);
1558 vma->vm_ops = &btrfs_file_vm_ops;
1559 vma->vm_flags |= VM_CAN_NONLINEAR;
1560
1561 return 0;
1562 }
1563
1564 static long btrfs_fallocate(struct file *file, int mode,
1565 loff_t offset, loff_t len)
1566 {
1567 struct inode *inode = file->f_path.dentry->d_inode;
1568 struct extent_state *cached_state = NULL;
1569 u64 cur_offset;
1570 u64 last_byte;
1571 u64 alloc_start;
1572 u64 alloc_end;
1573 u64 alloc_hint = 0;
1574 u64 locked_end;
1575 u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1576 struct extent_map *em;
1577 int ret;
1578
1579 alloc_start = offset & ~mask;
1580 alloc_end = (offset + len + mask) & ~mask;
1581
1582 /* We only support the FALLOC_FL_KEEP_SIZE mode */
1583 if (mode & ~FALLOC_FL_KEEP_SIZE)
1584 return -EOPNOTSUPP;
1585
1586 /*
1587 * wait for ordered IO before we have any locks. We'll loop again
1588 * below with the locks held.
1589 */
1590 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1591
1592 mutex_lock(&inode->i_mutex);
1593 ret = inode_newsize_ok(inode, alloc_end);
1594 if (ret)
1595 goto out;
1596
1597 if (alloc_start > inode->i_size) {
1598 ret = btrfs_cont_expand(inode, i_size_read(inode),
1599 alloc_start);
1600 if (ret)
1601 goto out;
1602 }
1603
1604 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
1605 if (ret)
1606 goto out;
1607
1608 locked_end = alloc_end - 1;
1609 while (1) {
1610 struct btrfs_ordered_extent *ordered;
1611
1612 /* the extent lock is ordered inside the running
1613 * transaction
1614 */
1615 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1616 locked_end, 0, &cached_state, GFP_NOFS);
1617 ordered = btrfs_lookup_first_ordered_extent(inode,
1618 alloc_end - 1);
1619 if (ordered &&
1620 ordered->file_offset + ordered->len > alloc_start &&
1621 ordered->file_offset < alloc_end) {
1622 btrfs_put_ordered_extent(ordered);
1623 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1624 alloc_start, locked_end,
1625 &cached_state, GFP_NOFS);
1626 /*
1627 * we can't wait on the range with the transaction
1628 * running or with the extent lock held
1629 */
1630 btrfs_wait_ordered_range(inode, alloc_start,
1631 alloc_end - alloc_start);
1632 } else {
1633 if (ordered)
1634 btrfs_put_ordered_extent(ordered);
1635 break;
1636 }
1637 }
1638
1639 cur_offset = alloc_start;
1640 while (1) {
1641 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1642 alloc_end - cur_offset, 0);
1643 BUG_ON(IS_ERR_OR_NULL(em));
1644 last_byte = min(extent_map_end(em), alloc_end);
1645 last_byte = (last_byte + mask) & ~mask;
1646 if (em->block_start == EXTENT_MAP_HOLE ||
1647 (cur_offset >= inode->i_size &&
1648 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1649 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1650 last_byte - cur_offset,
1651 1 << inode->i_blkbits,
1652 offset + len,
1653 &alloc_hint);
1654 if (ret < 0) {
1655 free_extent_map(em);
1656 break;
1657 }
1658 }
1659 free_extent_map(em);
1660
1661 cur_offset = last_byte;
1662 if (cur_offset >= alloc_end) {
1663 ret = 0;
1664 break;
1665 }
1666 }
1667 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1668 &cached_state, GFP_NOFS);
1669
1670 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
1671 out:
1672 mutex_unlock(&inode->i_mutex);
1673 return ret;
1674 }
1675
1676 static int find_desired_extent(struct inode *inode, loff_t *offset, int origin)
1677 {
1678 struct btrfs_root *root = BTRFS_I(inode)->root;
1679 struct extent_map *em;
1680 struct extent_state *cached_state = NULL;
1681 u64 lockstart = *offset;
1682 u64 lockend = i_size_read(inode);
1683 u64 start = *offset;
1684 u64 orig_start = *offset;
1685 u64 len = i_size_read(inode);
1686 u64 last_end = 0;
1687 int ret = 0;
1688
1689 lockend = max_t(u64, root->sectorsize, lockend);
1690 if (lockend <= lockstart)
1691 lockend = lockstart + root->sectorsize;
1692
1693 len = lockend - lockstart + 1;
1694
1695 len = max_t(u64, len, root->sectorsize);
1696 if (inode->i_size == 0)
1697 return -ENXIO;
1698
1699 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
1700 &cached_state, GFP_NOFS);
1701
1702 /*
1703 * Delalloc is such a pain. If we have a hole and we have pending
1704 * delalloc for a portion of the hole we will get back a hole that
1705 * exists for the entire range since it hasn't been actually written
1706 * yet. So to take care of this case we need to look for an extent just
1707 * before the position we want in case there is outstanding delalloc
1708 * going on here.
1709 */
1710 if (origin == SEEK_HOLE && start != 0) {
1711 if (start <= root->sectorsize)
1712 em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
1713 root->sectorsize, 0);
1714 else
1715 em = btrfs_get_extent_fiemap(inode, NULL, 0,
1716 start - root->sectorsize,
1717 root->sectorsize, 0);
1718 if (IS_ERR(em)) {
1719 ret = -ENXIO;
1720 goto out;
1721 }
1722 last_end = em->start + em->len;
1723 if (em->block_start == EXTENT_MAP_DELALLOC)
1724 last_end = min_t(u64, last_end, inode->i_size);
1725 free_extent_map(em);
1726 }
1727
1728 while (1) {
1729 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
1730 if (IS_ERR(em)) {
1731 ret = -ENXIO;
1732 break;
1733 }
1734
1735 if (em->block_start == EXTENT_MAP_HOLE) {
1736 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1737 if (last_end <= orig_start) {
1738 free_extent_map(em);
1739 ret = -ENXIO;
1740 break;
1741 }
1742 }
1743
1744 if (origin == SEEK_HOLE) {
1745 *offset = start;
1746 free_extent_map(em);
1747 break;
1748 }
1749 } else {
1750 if (origin == SEEK_DATA) {
1751 if (em->block_start == EXTENT_MAP_DELALLOC) {
1752 if (start >= inode->i_size) {
1753 free_extent_map(em);
1754 ret = -ENXIO;
1755 break;
1756 }
1757 }
1758
1759 *offset = start;
1760 free_extent_map(em);
1761 break;
1762 }
1763 }
1764
1765 start = em->start + em->len;
1766 last_end = em->start + em->len;
1767
1768 if (em->block_start == EXTENT_MAP_DELALLOC)
1769 last_end = min_t(u64, last_end, inode->i_size);
1770
1771 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1772 free_extent_map(em);
1773 ret = -ENXIO;
1774 break;
1775 }
1776 free_extent_map(em);
1777 cond_resched();
1778 }
1779 if (!ret)
1780 *offset = min(*offset, inode->i_size);
1781 out:
1782 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
1783 &cached_state, GFP_NOFS);
1784 return ret;
1785 }
1786
1787 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
1788 {
1789 struct inode *inode = file->f_mapping->host;
1790 int ret;
1791
1792 mutex_lock(&inode->i_mutex);
1793 switch (origin) {
1794 case SEEK_END:
1795 case SEEK_CUR:
1796 offset = generic_file_llseek_unlocked(file, offset, origin);
1797 goto out;
1798 case SEEK_DATA:
1799 case SEEK_HOLE:
1800 ret = find_desired_extent(inode, &offset, origin);
1801 if (ret) {
1802 mutex_unlock(&inode->i_mutex);
1803 return ret;
1804 }
1805 }
1806
1807 if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET))
1808 return -EINVAL;
1809 if (offset > inode->i_sb->s_maxbytes)
1810 return -EINVAL;
1811
1812 /* Special lock needed here? */
1813 if (offset != file->f_pos) {
1814 file->f_pos = offset;
1815 file->f_version = 0;
1816 }
1817 out:
1818 mutex_unlock(&inode->i_mutex);
1819 return offset;
1820 }
1821
1822 const struct file_operations btrfs_file_operations = {
1823 .llseek = btrfs_file_llseek,
1824 .read = do_sync_read,
1825 .write = do_sync_write,
1826 .aio_read = generic_file_aio_read,
1827 .splice_read = generic_file_splice_read,
1828 .aio_write = btrfs_file_aio_write,
1829 .mmap = btrfs_file_mmap,
1830 .open = generic_file_open,
1831 .release = btrfs_release_file,
1832 .fsync = btrfs_sync_file,
1833 .fallocate = btrfs_fallocate,
1834 .unlocked_ioctl = btrfs_ioctl,
1835 #ifdef CONFIG_COMPAT
1836 .compat_ioctl = btrfs_ioctl,
1837 #endif
1838 };
Linux Btrfs Development