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[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 <linux/btrfs.h>
34 #include "ctree.h"
35 #include "disk-io.h"
36 #include "transaction.h"
37 #include "btrfs_inode.h"
38 #include "print-tree.h"
39 #include "tree-log.h"
40 #include "locking.h"
41 #include "compat.h"
42 #include "volumes.h"
43
44 static struct kmem_cache *btrfs_inode_defrag_cachep;
45 /*
46 * when auto defrag is enabled we
47 * queue up these defrag structs to remember which
48 * inodes need defragging passes
49 */
50 struct inode_defrag {
51 struct rb_node rb_node;
52 /* objectid */
53 u64 ino;
54 /*
55 * transid where the defrag was added, we search for
56 * extents newer than this
57 */
58 u64 transid;
59
60 /* root objectid */
61 u64 root;
62
63 /* last offset we were able to defrag */
64 u64 last_offset;
65
66 /* if we've wrapped around back to zero once already */
67 int cycled;
68 };
69
70 static int __compare_inode_defrag(struct inode_defrag *defrag1,
71 struct inode_defrag *defrag2)
72 {
73 if (defrag1->root > defrag2->root)
74 return 1;
75 else if (defrag1->root < defrag2->root)
76 return -1;
77 else if (defrag1->ino > defrag2->ino)
78 return 1;
79 else if (defrag1->ino < defrag2->ino)
80 return -1;
81 else
82 return 0;
83 }
84
85 /* pop a record for an inode into the defrag tree. The lock
86 * must be held already
87 *
88 * If you're inserting a record for an older transid than an
89 * existing record, the transid already in the tree is lowered
90 *
91 * If an existing record is found the defrag item you
92 * pass in is freed
93 */
94 static int __btrfs_add_inode_defrag(struct inode *inode,
95 struct inode_defrag *defrag)
96 {
97 struct btrfs_root *root = BTRFS_I(inode)->root;
98 struct inode_defrag *entry;
99 struct rb_node **p;
100 struct rb_node *parent = NULL;
101 int ret;
102
103 p = &root->fs_info->defrag_inodes.rb_node;
104 while (*p) {
105 parent = *p;
106 entry = rb_entry(parent, struct inode_defrag, rb_node);
107
108 ret = __compare_inode_defrag(defrag, entry);
109 if (ret < 0)
110 p = &parent->rb_left;
111 else if (ret > 0)
112 p = &parent->rb_right;
113 else {
114 /* if we're reinserting an entry for
115 * an old defrag run, make sure to
116 * lower the transid of our existing record
117 */
118 if (defrag->transid < entry->transid)
119 entry->transid = defrag->transid;
120 if (defrag->last_offset > entry->last_offset)
121 entry->last_offset = defrag->last_offset;
122 return -EEXIST;
123 }
124 }
125 set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
126 rb_link_node(&defrag->rb_node, parent, p);
127 rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
128 return 0;
129 }
130
131 static inline int __need_auto_defrag(struct btrfs_root *root)
132 {
133 if (!btrfs_test_opt(root, AUTO_DEFRAG))
134 return 0;
135
136 if (btrfs_fs_closing(root->fs_info))
137 return 0;
138
139 return 1;
140 }
141
142 /*
143 * insert a defrag record for this inode if auto defrag is
144 * enabled
145 */
146 int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
147 struct inode *inode)
148 {
149 struct btrfs_root *root = BTRFS_I(inode)->root;
150 struct inode_defrag *defrag;
151 u64 transid;
152 int ret;
153
154 if (!__need_auto_defrag(root))
155 return 0;
156
157 if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
158 return 0;
159
160 if (trans)
161 transid = trans->transid;
162 else
163 transid = BTRFS_I(inode)->root->last_trans;
164
165 defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
166 if (!defrag)
167 return -ENOMEM;
168
169 defrag->ino = btrfs_ino(inode);
170 defrag->transid = transid;
171 defrag->root = root->root_key.objectid;
172
173 spin_lock(&root->fs_info->defrag_inodes_lock);
174 if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) {
175 /*
176 * If we set IN_DEFRAG flag and evict the inode from memory,
177 * and then re-read this inode, this new inode doesn't have
178 * IN_DEFRAG flag. At the case, we may find the existed defrag.
179 */
180 ret = __btrfs_add_inode_defrag(inode, defrag);
181 if (ret)
182 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
183 } else {
184 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
185 }
186 spin_unlock(&root->fs_info->defrag_inodes_lock);
187 return 0;
188 }
189
190 /*
191 * Requeue the defrag object. If there is a defrag object that points to
192 * the same inode in the tree, we will merge them together (by
193 * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
194 */
195 static void btrfs_requeue_inode_defrag(struct inode *inode,
196 struct inode_defrag *defrag)
197 {
198 struct btrfs_root *root = BTRFS_I(inode)->root;
199 int ret;
200
201 if (!__need_auto_defrag(root))
202 goto out;
203
204 /*
205 * Here we don't check the IN_DEFRAG flag, because we need merge
206 * them together.
207 */
208 spin_lock(&root->fs_info->defrag_inodes_lock);
209 ret = __btrfs_add_inode_defrag(inode, defrag);
210 spin_unlock(&root->fs_info->defrag_inodes_lock);
211 if (ret)
212 goto out;
213 return;
214 out:
215 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
216 }
217
218 /*
219 * pick the defragable inode that we want, if it doesn't exist, we will get
220 * the next one.
221 */
222 static struct inode_defrag *
223 btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
224 {
225 struct inode_defrag *entry = NULL;
226 struct inode_defrag tmp;
227 struct rb_node *p;
228 struct rb_node *parent = NULL;
229 int ret;
230
231 tmp.ino = ino;
232 tmp.root = root;
233
234 spin_lock(&fs_info->defrag_inodes_lock);
235 p = fs_info->defrag_inodes.rb_node;
236 while (p) {
237 parent = p;
238 entry = rb_entry(parent, struct inode_defrag, rb_node);
239
240 ret = __compare_inode_defrag(&tmp, entry);
241 if (ret < 0)
242 p = parent->rb_left;
243 else if (ret > 0)
244 p = parent->rb_right;
245 else
246 goto out;
247 }
248
249 if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
250 parent = rb_next(parent);
251 if (parent)
252 entry = rb_entry(parent, struct inode_defrag, rb_node);
253 else
254 entry = NULL;
255 }
256 out:
257 if (entry)
258 rb_erase(parent, &fs_info->defrag_inodes);
259 spin_unlock(&fs_info->defrag_inodes_lock);
260 return entry;
261 }
262
263 void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
264 {
265 struct inode_defrag *defrag;
266 struct rb_node *node;
267
268 spin_lock(&fs_info->defrag_inodes_lock);
269 node = rb_first(&fs_info->defrag_inodes);
270 while (node) {
271 rb_erase(node, &fs_info->defrag_inodes);
272 defrag = rb_entry(node, struct inode_defrag, rb_node);
273 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
274
275 if (need_resched()) {
276 spin_unlock(&fs_info->defrag_inodes_lock);
277 cond_resched();
278 spin_lock(&fs_info->defrag_inodes_lock);
279 }
280
281 node = rb_first(&fs_info->defrag_inodes);
282 }
283 spin_unlock(&fs_info->defrag_inodes_lock);
284 }
285
286 #define BTRFS_DEFRAG_BATCH 1024
287
288 static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
289 struct inode_defrag *defrag)
290 {
291 struct btrfs_root *inode_root;
292 struct inode *inode;
293 struct btrfs_key key;
294 struct btrfs_ioctl_defrag_range_args range;
295 int num_defrag;
296 int index;
297 int ret;
298
299 /* get the inode */
300 key.objectid = defrag->root;
301 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
302 key.offset = (u64)-1;
303
304 index = srcu_read_lock(&fs_info->subvol_srcu);
305
306 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
307 if (IS_ERR(inode_root)) {
308 ret = PTR_ERR(inode_root);
309 goto cleanup;
310 }
311
312 key.objectid = defrag->ino;
313 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
314 key.offset = 0;
315 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
316 if (IS_ERR(inode)) {
317 ret = PTR_ERR(inode);
318 goto cleanup;
319 }
320 srcu_read_unlock(&fs_info->subvol_srcu, index);
321
322 /* do a chunk of defrag */
323 clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
324 memset(&range, 0, sizeof(range));
325 range.len = (u64)-1;
326 range.start = defrag->last_offset;
327
328 sb_start_write(fs_info->sb);
329 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
330 BTRFS_DEFRAG_BATCH);
331 sb_end_write(fs_info->sb);
332 /*
333 * if we filled the whole defrag batch, there
334 * must be more work to do. Queue this defrag
335 * again
336 */
337 if (num_defrag == BTRFS_DEFRAG_BATCH) {
338 defrag->last_offset = range.start;
339 btrfs_requeue_inode_defrag(inode, defrag);
340 } else if (defrag->last_offset && !defrag->cycled) {
341 /*
342 * we didn't fill our defrag batch, but
343 * we didn't start at zero. Make sure we loop
344 * around to the start of the file.
345 */
346 defrag->last_offset = 0;
347 defrag->cycled = 1;
348 btrfs_requeue_inode_defrag(inode, defrag);
349 } else {
350 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
351 }
352
353 iput(inode);
354 return 0;
355 cleanup:
356 srcu_read_unlock(&fs_info->subvol_srcu, index);
357 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
358 return ret;
359 }
360
361 /*
362 * run through the list of inodes in the FS that need
363 * defragging
364 */
365 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
366 {
367 struct inode_defrag *defrag;
368 u64 first_ino = 0;
369 u64 root_objectid = 0;
370
371 atomic_inc(&fs_info->defrag_running);
372 while(1) {
373 /* Pause the auto defragger. */
374 if (test_bit(BTRFS_FS_STATE_REMOUNTING,
375 &fs_info->fs_state))
376 break;
377
378 if (!__need_auto_defrag(fs_info->tree_root))
379 break;
380
381 /* find an inode to defrag */
382 defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
383 first_ino);
384 if (!defrag) {
385 if (root_objectid || first_ino) {
386 root_objectid = 0;
387 first_ino = 0;
388 continue;
389 } else {
390 break;
391 }
392 }
393
394 first_ino = defrag->ino + 1;
395 root_objectid = defrag->root;
396
397 __btrfs_run_defrag_inode(fs_info, defrag);
398 }
399 atomic_dec(&fs_info->defrag_running);
400
401 /*
402 * during unmount, we use the transaction_wait queue to
403 * wait for the defragger to stop
404 */
405 wake_up(&fs_info->transaction_wait);
406 return 0;
407 }
408
409 /* simple helper to fault in pages and copy. This should go away
410 * and be replaced with calls into generic code.
411 */
412 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
413 size_t write_bytes,
414 struct page **prepared_pages,
415 struct iov_iter *i)
416 {
417 size_t copied = 0;
418 size_t total_copied = 0;
419 int pg = 0;
420 int offset = pos & (PAGE_CACHE_SIZE - 1);
421
422 while (write_bytes > 0) {
423 size_t count = min_t(size_t,
424 PAGE_CACHE_SIZE - offset, write_bytes);
425 struct page *page = prepared_pages[pg];
426 /*
427 * Copy data from userspace to the current page
428 *
429 * Disable pagefault to avoid recursive lock since
430 * the pages are already locked
431 */
432 pagefault_disable();
433 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
434 pagefault_enable();
435
436 /* Flush processor's dcache for this page */
437 flush_dcache_page(page);
438
439 /*
440 * if we get a partial write, we can end up with
441 * partially up to date pages. These add
442 * a lot of complexity, so make sure they don't
443 * happen by forcing this copy to be retried.
444 *
445 * The rest of the btrfs_file_write code will fall
446 * back to page at a time copies after we return 0.
447 */
448 if (!PageUptodate(page) && copied < count)
449 copied = 0;
450
451 iov_iter_advance(i, copied);
452 write_bytes -= copied;
453 total_copied += copied;
454
455 /* Return to btrfs_file_aio_write to fault page */
456 if (unlikely(copied == 0))
457 break;
458
459 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
460 offset += copied;
461 } else {
462 pg++;
463 offset = 0;
464 }
465 }
466 return total_copied;
467 }
468
469 /*
470 * unlocks pages after btrfs_file_write is done with them
471 */
472 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
473 {
474 size_t i;
475 for (i = 0; i < num_pages; i++) {
476 /* page checked is some magic around finding pages that
477 * have been modified without going through btrfs_set_page_dirty
478 * clear it here
479 */
480 ClearPageChecked(pages[i]);
481 unlock_page(pages[i]);
482 mark_page_accessed(pages[i]);
483 page_cache_release(pages[i]);
484 }
485 }
486
487 /*
488 * after copy_from_user, pages need to be dirtied and we need to make
489 * sure holes are created between the current EOF and the start of
490 * any next extents (if required).
491 *
492 * this also makes the decision about creating an inline extent vs
493 * doing real data extents, marking pages dirty and delalloc as required.
494 */
495 int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
496 struct page **pages, size_t num_pages,
497 loff_t pos, size_t write_bytes,
498 struct extent_state **cached)
499 {
500 int err = 0;
501 int i;
502 u64 num_bytes;
503 u64 start_pos;
504 u64 end_of_last_block;
505 u64 end_pos = pos + write_bytes;
506 loff_t isize = i_size_read(inode);
507
508 start_pos = pos & ~((u64)root->sectorsize - 1);
509 num_bytes = ALIGN(write_bytes + pos - start_pos, root->sectorsize);
510
511 end_of_last_block = start_pos + num_bytes - 1;
512 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
513 cached);
514 if (err)
515 return err;
516
517 for (i = 0; i < num_pages; i++) {
518 struct page *p = pages[i];
519 SetPageUptodate(p);
520 ClearPageChecked(p);
521 set_page_dirty(p);
522 }
523
524 /*
525 * we've only changed i_size in ram, and we haven't updated
526 * the disk i_size. There is no need to log the inode
527 * at this time.
528 */
529 if (end_pos > isize)
530 i_size_write(inode, end_pos);
531 return 0;
532 }
533
534 /*
535 * this drops all the extents in the cache that intersect the range
536 * [start, end]. Existing extents are split as required.
537 */
538 void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
539 int skip_pinned)
540 {
541 struct extent_map *em;
542 struct extent_map *split = NULL;
543 struct extent_map *split2 = NULL;
544 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
545 u64 len = end - start + 1;
546 u64 gen;
547 int ret;
548 int testend = 1;
549 unsigned long flags;
550 int compressed = 0;
551 bool modified;
552
553 WARN_ON(end < start);
554 if (end == (u64)-1) {
555 len = (u64)-1;
556 testend = 0;
557 }
558 while (1) {
559 int no_splits = 0;
560
561 modified = false;
562 if (!split)
563 split = alloc_extent_map();
564 if (!split2)
565 split2 = alloc_extent_map();
566 if (!split || !split2)
567 no_splits = 1;
568
569 write_lock(&em_tree->lock);
570 em = lookup_extent_mapping(em_tree, start, len);
571 if (!em) {
572 write_unlock(&em_tree->lock);
573 break;
574 }
575 flags = em->flags;
576 gen = em->generation;
577 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
578 if (testend && em->start + em->len >= start + len) {
579 free_extent_map(em);
580 write_unlock(&em_tree->lock);
581 break;
582 }
583 start = em->start + em->len;
584 if (testend)
585 len = start + len - (em->start + em->len);
586 free_extent_map(em);
587 write_unlock(&em_tree->lock);
588 continue;
589 }
590 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
591 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
592 clear_bit(EXTENT_FLAG_LOGGING, &flags);
593 modified = !list_empty(&em->list);
594 remove_extent_mapping(em_tree, em);
595 if (no_splits)
596 goto next;
597
598 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
599 em->start < start) {
600 split->start = em->start;
601 split->len = start - em->start;
602 split->orig_start = em->orig_start;
603 split->block_start = em->block_start;
604
605 if (compressed)
606 split->block_len = em->block_len;
607 else
608 split->block_len = split->len;
609 split->ram_bytes = em->ram_bytes;
610 split->orig_block_len = max(split->block_len,
611 em->orig_block_len);
612 split->generation = gen;
613 split->bdev = em->bdev;
614 split->flags = flags;
615 split->compress_type = em->compress_type;
616 ret = add_extent_mapping(em_tree, split, modified);
617 BUG_ON(ret); /* Logic error */
618 free_extent_map(split);
619 split = split2;
620 split2 = NULL;
621 }
622 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
623 testend && em->start + em->len > start + len) {
624 u64 diff = start + len - em->start;
625
626 split->start = start + len;
627 split->len = em->start + em->len - (start + len);
628 split->bdev = em->bdev;
629 split->flags = flags;
630 split->compress_type = em->compress_type;
631 split->generation = gen;
632 split->orig_block_len = max(em->block_len,
633 em->orig_block_len);
634 split->ram_bytes = em->ram_bytes;
635
636 if (compressed) {
637 split->block_len = em->block_len;
638 split->block_start = em->block_start;
639 split->orig_start = em->orig_start;
640 } else {
641 split->block_len = split->len;
642 split->block_start = em->block_start + diff;
643 split->orig_start = em->orig_start;
644 }
645
646 ret = add_extent_mapping(em_tree, split, modified);
647 BUG_ON(ret); /* Logic error */
648 free_extent_map(split);
649 split = NULL;
650 }
651 next:
652 write_unlock(&em_tree->lock);
653
654 /* once for us */
655 free_extent_map(em);
656 /* once for the tree*/
657 free_extent_map(em);
658 }
659 if (split)
660 free_extent_map(split);
661 if (split2)
662 free_extent_map(split2);
663 }
664
665 /*
666 * this is very complex, but the basic idea is to drop all extents
667 * in the range start - end. hint_block is filled in with a block number
668 * that would be a good hint to the block allocator for this file.
669 *
670 * If an extent intersects the range but is not entirely inside the range
671 * it is either truncated or split. Anything entirely inside the range
672 * is deleted from the tree.
673 */
674 int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
675 struct btrfs_root *root, struct inode *inode,
676 struct btrfs_path *path, u64 start, u64 end,
677 u64 *drop_end, int drop_cache)
678 {
679 struct extent_buffer *leaf;
680 struct btrfs_file_extent_item *fi;
681 struct btrfs_key key;
682 struct btrfs_key new_key;
683 u64 ino = btrfs_ino(inode);
684 u64 search_start = start;
685 u64 disk_bytenr = 0;
686 u64 num_bytes = 0;
687 u64 extent_offset = 0;
688 u64 extent_end = 0;
689 int del_nr = 0;
690 int del_slot = 0;
691 int extent_type;
692 int recow;
693 int ret;
694 int modify_tree = -1;
695 int update_refs = (root->ref_cows || root == root->fs_info->tree_root);
696 int found = 0;
697
698 if (drop_cache)
699 btrfs_drop_extent_cache(inode, start, end - 1, 0);
700
701 if (start >= BTRFS_I(inode)->disk_i_size)
702 modify_tree = 0;
703
704 while (1) {
705 recow = 0;
706 ret = btrfs_lookup_file_extent(trans, root, path, ino,
707 search_start, modify_tree);
708 if (ret < 0)
709 break;
710 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
711 leaf = path->nodes[0];
712 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
713 if (key.objectid == ino &&
714 key.type == BTRFS_EXTENT_DATA_KEY)
715 path->slots[0]--;
716 }
717 ret = 0;
718 next_slot:
719 leaf = path->nodes[0];
720 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
721 BUG_ON(del_nr > 0);
722 ret = btrfs_next_leaf(root, path);
723 if (ret < 0)
724 break;
725 if (ret > 0) {
726 ret = 0;
727 break;
728 }
729 leaf = path->nodes[0];
730 recow = 1;
731 }
732
733 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
734 if (key.objectid > ino ||
735 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
736 break;
737
738 fi = btrfs_item_ptr(leaf, path->slots[0],
739 struct btrfs_file_extent_item);
740 extent_type = btrfs_file_extent_type(leaf, fi);
741
742 if (extent_type == BTRFS_FILE_EXTENT_REG ||
743 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
744 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
745 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
746 extent_offset = btrfs_file_extent_offset(leaf, fi);
747 extent_end = key.offset +
748 btrfs_file_extent_num_bytes(leaf, fi);
749 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
750 extent_end = key.offset +
751 btrfs_file_extent_inline_len(leaf, fi);
752 } else {
753 WARN_ON(1);
754 extent_end = search_start;
755 }
756
757 if (extent_end <= search_start) {
758 path->slots[0]++;
759 goto next_slot;
760 }
761
762 found = 1;
763 search_start = max(key.offset, start);
764 if (recow || !modify_tree) {
765 modify_tree = -1;
766 btrfs_release_path(path);
767 continue;
768 }
769
770 /*
771 * | - range to drop - |
772 * | -------- extent -------- |
773 */
774 if (start > key.offset && end < extent_end) {
775 BUG_ON(del_nr > 0);
776 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
777
778 memcpy(&new_key, &key, sizeof(new_key));
779 new_key.offset = start;
780 ret = btrfs_duplicate_item(trans, root, path,
781 &new_key);
782 if (ret == -EAGAIN) {
783 btrfs_release_path(path);
784 continue;
785 }
786 if (ret < 0)
787 break;
788
789 leaf = path->nodes[0];
790 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
791 struct btrfs_file_extent_item);
792 btrfs_set_file_extent_num_bytes(leaf, fi,
793 start - key.offset);
794
795 fi = btrfs_item_ptr(leaf, path->slots[0],
796 struct btrfs_file_extent_item);
797
798 extent_offset += start - key.offset;
799 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
800 btrfs_set_file_extent_num_bytes(leaf, fi,
801 extent_end - start);
802 btrfs_mark_buffer_dirty(leaf);
803
804 if (update_refs && disk_bytenr > 0) {
805 ret = btrfs_inc_extent_ref(trans, root,
806 disk_bytenr, num_bytes, 0,
807 root->root_key.objectid,
808 new_key.objectid,
809 start - extent_offset, 0);
810 BUG_ON(ret); /* -ENOMEM */
811 }
812 key.offset = start;
813 }
814 /*
815 * | ---- range to drop ----- |
816 * | -------- extent -------- |
817 */
818 if (start <= key.offset && end < extent_end) {
819 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
820
821 memcpy(&new_key, &key, sizeof(new_key));
822 new_key.offset = end;
823 btrfs_set_item_key_safe(root, path, &new_key);
824
825 extent_offset += end - key.offset;
826 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
827 btrfs_set_file_extent_num_bytes(leaf, fi,
828 extent_end - end);
829 btrfs_mark_buffer_dirty(leaf);
830 if (update_refs && disk_bytenr > 0)
831 inode_sub_bytes(inode, end - key.offset);
832 break;
833 }
834
835 search_start = extent_end;
836 /*
837 * | ---- range to drop ----- |
838 * | -------- extent -------- |
839 */
840 if (start > key.offset && end >= extent_end) {
841 BUG_ON(del_nr > 0);
842 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
843
844 btrfs_set_file_extent_num_bytes(leaf, fi,
845 start - key.offset);
846 btrfs_mark_buffer_dirty(leaf);
847 if (update_refs && disk_bytenr > 0)
848 inode_sub_bytes(inode, extent_end - start);
849 if (end == extent_end)
850 break;
851
852 path->slots[0]++;
853 goto next_slot;
854 }
855
856 /*
857 * | ---- range to drop ----- |
858 * | ------ extent ------ |
859 */
860 if (start <= key.offset && end >= extent_end) {
861 if (del_nr == 0) {
862 del_slot = path->slots[0];
863 del_nr = 1;
864 } else {
865 BUG_ON(del_slot + del_nr != path->slots[0]);
866 del_nr++;
867 }
868
869 if (update_refs &&
870 extent_type == BTRFS_FILE_EXTENT_INLINE) {
871 inode_sub_bytes(inode,
872 extent_end - key.offset);
873 extent_end = ALIGN(extent_end,
874 root->sectorsize);
875 } else if (update_refs && disk_bytenr > 0) {
876 ret = btrfs_free_extent(trans, root,
877 disk_bytenr, num_bytes, 0,
878 root->root_key.objectid,
879 key.objectid, key.offset -
880 extent_offset, 0);
881 BUG_ON(ret); /* -ENOMEM */
882 inode_sub_bytes(inode,
883 extent_end - key.offset);
884 }
885
886 if (end == extent_end)
887 break;
888
889 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
890 path->slots[0]++;
891 goto next_slot;
892 }
893
894 ret = btrfs_del_items(trans, root, path, del_slot,
895 del_nr);
896 if (ret) {
897 btrfs_abort_transaction(trans, root, ret);
898 break;
899 }
900
901 del_nr = 0;
902 del_slot = 0;
903
904 btrfs_release_path(path);
905 continue;
906 }
907
908 BUG_ON(1);
909 }
910
911 if (!ret && del_nr > 0) {
912 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
913 if (ret)
914 btrfs_abort_transaction(trans, root, ret);
915 }
916
917 if (drop_end)
918 *drop_end = found ? min(end, extent_end) : end;
919 btrfs_release_path(path);
920 return ret;
921 }
922
923 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
924 struct btrfs_root *root, struct inode *inode, u64 start,
925 u64 end, int drop_cache)
926 {
927 struct btrfs_path *path;
928 int ret;
929
930 path = btrfs_alloc_path();
931 if (!path)
932 return -ENOMEM;
933 ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
934 drop_cache);
935 btrfs_free_path(path);
936 return ret;
937 }
938
939 static int extent_mergeable(struct extent_buffer *leaf, int slot,
940 u64 objectid, u64 bytenr, u64 orig_offset,
941 u64 *start, u64 *end)
942 {
943 struct btrfs_file_extent_item *fi;
944 struct btrfs_key key;
945 u64 extent_end;
946
947 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
948 return 0;
949
950 btrfs_item_key_to_cpu(leaf, &key, slot);
951 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
952 return 0;
953
954 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
955 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
956 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
957 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
958 btrfs_file_extent_compression(leaf, fi) ||
959 btrfs_file_extent_encryption(leaf, fi) ||
960 btrfs_file_extent_other_encoding(leaf, fi))
961 return 0;
962
963 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
964 if ((*start && *start != key.offset) || (*end && *end != extent_end))
965 return 0;
966
967 *start = key.offset;
968 *end = extent_end;
969 return 1;
970 }
971
972 /*
973 * Mark extent in the range start - end as written.
974 *
975 * This changes extent type from 'pre-allocated' to 'regular'. If only
976 * part of extent is marked as written, the extent will be split into
977 * two or three.
978 */
979 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
980 struct inode *inode, u64 start, u64 end)
981 {
982 struct btrfs_root *root = BTRFS_I(inode)->root;
983 struct extent_buffer *leaf;
984 struct btrfs_path *path;
985 struct btrfs_file_extent_item *fi;
986 struct btrfs_key key;
987 struct btrfs_key new_key;
988 u64 bytenr;
989 u64 num_bytes;
990 u64 extent_end;
991 u64 orig_offset;
992 u64 other_start;
993 u64 other_end;
994 u64 split;
995 int del_nr = 0;
996 int del_slot = 0;
997 int recow;
998 int ret;
999 u64 ino = btrfs_ino(inode);
1000
1001 path = btrfs_alloc_path();
1002 if (!path)
1003 return -ENOMEM;
1004 again:
1005 recow = 0;
1006 split = start;
1007 key.objectid = ino;
1008 key.type = BTRFS_EXTENT_DATA_KEY;
1009 key.offset = split;
1010
1011 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1012 if (ret < 0)
1013 goto out;
1014 if (ret > 0 && path->slots[0] > 0)
1015 path->slots[0]--;
1016
1017 leaf = path->nodes[0];
1018 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1019 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
1020 fi = btrfs_item_ptr(leaf, path->slots[0],
1021 struct btrfs_file_extent_item);
1022 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
1023 BTRFS_FILE_EXTENT_PREALLOC);
1024 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1025 BUG_ON(key.offset > start || extent_end < end);
1026
1027 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1028 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1029 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1030 memcpy(&new_key, &key, sizeof(new_key));
1031
1032 if (start == key.offset && end < extent_end) {
1033 other_start = 0;
1034 other_end = start;
1035 if (extent_mergeable(leaf, path->slots[0] - 1,
1036 ino, bytenr, orig_offset,
1037 &other_start, &other_end)) {
1038 new_key.offset = end;
1039 btrfs_set_item_key_safe(root, path, &new_key);
1040 fi = btrfs_item_ptr(leaf, path->slots[0],
1041 struct btrfs_file_extent_item);
1042 btrfs_set_file_extent_generation(leaf, fi,
1043 trans->transid);
1044 btrfs_set_file_extent_num_bytes(leaf, fi,
1045 extent_end - end);
1046 btrfs_set_file_extent_offset(leaf, fi,
1047 end - orig_offset);
1048 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1049 struct btrfs_file_extent_item);
1050 btrfs_set_file_extent_generation(leaf, fi,
1051 trans->transid);
1052 btrfs_set_file_extent_num_bytes(leaf, fi,
1053 end - other_start);
1054 btrfs_mark_buffer_dirty(leaf);
1055 goto out;
1056 }
1057 }
1058
1059 if (start > key.offset && end == extent_end) {
1060 other_start = end;
1061 other_end = 0;
1062 if (extent_mergeable(leaf, path->slots[0] + 1,
1063 ino, bytenr, orig_offset,
1064 &other_start, &other_end)) {
1065 fi = btrfs_item_ptr(leaf, path->slots[0],
1066 struct btrfs_file_extent_item);
1067 btrfs_set_file_extent_num_bytes(leaf, fi,
1068 start - key.offset);
1069 btrfs_set_file_extent_generation(leaf, fi,
1070 trans->transid);
1071 path->slots[0]++;
1072 new_key.offset = start;
1073 btrfs_set_item_key_safe(root, path, &new_key);
1074
1075 fi = btrfs_item_ptr(leaf, path->slots[0],
1076 struct btrfs_file_extent_item);
1077 btrfs_set_file_extent_generation(leaf, fi,
1078 trans->transid);
1079 btrfs_set_file_extent_num_bytes(leaf, fi,
1080 other_end - start);
1081 btrfs_set_file_extent_offset(leaf, fi,
1082 start - orig_offset);
1083 btrfs_mark_buffer_dirty(leaf);
1084 goto out;
1085 }
1086 }
1087
1088 while (start > key.offset || end < extent_end) {
1089 if (key.offset == start)
1090 split = end;
1091
1092 new_key.offset = split;
1093 ret = btrfs_duplicate_item(trans, root, path, &new_key);
1094 if (ret == -EAGAIN) {
1095 btrfs_release_path(path);
1096 goto again;
1097 }
1098 if (ret < 0) {
1099 btrfs_abort_transaction(trans, root, ret);
1100 goto out;
1101 }
1102
1103 leaf = path->nodes[0];
1104 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1105 struct btrfs_file_extent_item);
1106 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1107 btrfs_set_file_extent_num_bytes(leaf, fi,
1108 split - key.offset);
1109
1110 fi = btrfs_item_ptr(leaf, path->slots[0],
1111 struct btrfs_file_extent_item);
1112
1113 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1114 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1115 btrfs_set_file_extent_num_bytes(leaf, fi,
1116 extent_end - split);
1117 btrfs_mark_buffer_dirty(leaf);
1118
1119 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
1120 root->root_key.objectid,
1121 ino, orig_offset, 0);
1122 BUG_ON(ret); /* -ENOMEM */
1123
1124 if (split == start) {
1125 key.offset = start;
1126 } else {
1127 BUG_ON(start != key.offset);
1128 path->slots[0]--;
1129 extent_end = end;
1130 }
1131 recow = 1;
1132 }
1133
1134 other_start = end;
1135 other_end = 0;
1136 if (extent_mergeable(leaf, path->slots[0] + 1,
1137 ino, bytenr, orig_offset,
1138 &other_start, &other_end)) {
1139 if (recow) {
1140 btrfs_release_path(path);
1141 goto again;
1142 }
1143 extent_end = other_end;
1144 del_slot = path->slots[0] + 1;
1145 del_nr++;
1146 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1147 0, root->root_key.objectid,
1148 ino, orig_offset, 0);
1149 BUG_ON(ret); /* -ENOMEM */
1150 }
1151 other_start = 0;
1152 other_end = start;
1153 if (extent_mergeable(leaf, path->slots[0] - 1,
1154 ino, bytenr, orig_offset,
1155 &other_start, &other_end)) {
1156 if (recow) {
1157 btrfs_release_path(path);
1158 goto again;
1159 }
1160 key.offset = other_start;
1161 del_slot = path->slots[0];
1162 del_nr++;
1163 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1164 0, root->root_key.objectid,
1165 ino, orig_offset, 0);
1166 BUG_ON(ret); /* -ENOMEM */
1167 }
1168 if (del_nr == 0) {
1169 fi = btrfs_item_ptr(leaf, path->slots[0],
1170 struct btrfs_file_extent_item);
1171 btrfs_set_file_extent_type(leaf, fi,
1172 BTRFS_FILE_EXTENT_REG);
1173 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1174 btrfs_mark_buffer_dirty(leaf);
1175 } else {
1176 fi = btrfs_item_ptr(leaf, del_slot - 1,
1177 struct btrfs_file_extent_item);
1178 btrfs_set_file_extent_type(leaf, fi,
1179 BTRFS_FILE_EXTENT_REG);
1180 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1181 btrfs_set_file_extent_num_bytes(leaf, fi,
1182 extent_end - key.offset);
1183 btrfs_mark_buffer_dirty(leaf);
1184
1185 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1186 if (ret < 0) {
1187 btrfs_abort_transaction(trans, root, ret);
1188 goto out;
1189 }
1190 }
1191 out:
1192 btrfs_free_path(path);
1193 return 0;
1194 }
1195
1196 /*
1197 * on error we return an unlocked page and the error value
1198 * on success we return a locked page and 0
1199 */
1200 static int prepare_uptodate_page(struct page *page, u64 pos,
1201 bool force_uptodate)
1202 {
1203 int ret = 0;
1204
1205 if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
1206 !PageUptodate(page)) {
1207 ret = btrfs_readpage(NULL, page);
1208 if (ret)
1209 return ret;
1210 lock_page(page);
1211 if (!PageUptodate(page)) {
1212 unlock_page(page);
1213 return -EIO;
1214 }
1215 }
1216 return 0;
1217 }
1218
1219 /*
1220 * this gets pages into the page cache and locks them down, it also properly
1221 * waits for data=ordered extents to finish before allowing the pages to be
1222 * modified.
1223 */
1224 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1225 struct page **pages, size_t num_pages,
1226 loff_t pos, unsigned long first_index,
1227 size_t write_bytes, bool force_uptodate)
1228 {
1229 struct extent_state *cached_state = NULL;
1230 int i;
1231 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1232 struct inode *inode = file_inode(file);
1233 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1234 int err = 0;
1235 int faili = 0;
1236 u64 start_pos;
1237 u64 last_pos;
1238
1239 start_pos = pos & ~((u64)root->sectorsize - 1);
1240 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1241
1242 again:
1243 for (i = 0; i < num_pages; i++) {
1244 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1245 mask | __GFP_WRITE);
1246 if (!pages[i]) {
1247 faili = i - 1;
1248 err = -ENOMEM;
1249 goto fail;
1250 }
1251
1252 if (i == 0)
1253 err = prepare_uptodate_page(pages[i], pos,
1254 force_uptodate);
1255 if (i == num_pages - 1)
1256 err = prepare_uptodate_page(pages[i],
1257 pos + write_bytes, false);
1258 if (err) {
1259 page_cache_release(pages[i]);
1260 faili = i - 1;
1261 goto fail;
1262 }
1263 wait_on_page_writeback(pages[i]);
1264 }
1265 err = 0;
1266 if (start_pos < inode->i_size) {
1267 struct btrfs_ordered_extent *ordered;
1268 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1269 start_pos, last_pos - 1, 0, &cached_state);
1270 ordered = btrfs_lookup_first_ordered_extent(inode,
1271 last_pos - 1);
1272 if (ordered &&
1273 ordered->file_offset + ordered->len > start_pos &&
1274 ordered->file_offset < last_pos) {
1275 btrfs_put_ordered_extent(ordered);
1276 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1277 start_pos, last_pos - 1,
1278 &cached_state, GFP_NOFS);
1279 for (i = 0; i < num_pages; i++) {
1280 unlock_page(pages[i]);
1281 page_cache_release(pages[i]);
1282 }
1283 btrfs_wait_ordered_range(inode, start_pos,
1284 last_pos - start_pos);
1285 goto again;
1286 }
1287 if (ordered)
1288 btrfs_put_ordered_extent(ordered);
1289
1290 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1291 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1292 EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
1293 0, 0, &cached_state, GFP_NOFS);
1294 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1295 start_pos, last_pos - 1, &cached_state,
1296 GFP_NOFS);
1297 }
1298 for (i = 0; i < num_pages; i++) {
1299 if (clear_page_dirty_for_io(pages[i]))
1300 account_page_redirty(pages[i]);
1301 set_page_extent_mapped(pages[i]);
1302 WARN_ON(!PageLocked(pages[i]));
1303 }
1304 return 0;
1305 fail:
1306 while (faili >= 0) {
1307 unlock_page(pages[faili]);
1308 page_cache_release(pages[faili]);
1309 faili--;
1310 }
1311 return err;
1312
1313 }
1314
1315 static noinline ssize_t __btrfs_buffered_write(struct file *file,
1316 struct iov_iter *i,
1317 loff_t pos)
1318 {
1319 struct inode *inode = file_inode(file);
1320 struct btrfs_root *root = BTRFS_I(inode)->root;
1321 struct page **pages = NULL;
1322 unsigned long first_index;
1323 size_t num_written = 0;
1324 int nrptrs;
1325 int ret = 0;
1326 bool force_page_uptodate = false;
1327
1328 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1329 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1330 (sizeof(struct page *)));
1331 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1332 nrptrs = max(nrptrs, 8);
1333 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1334 if (!pages)
1335 return -ENOMEM;
1336
1337 first_index = pos >> PAGE_CACHE_SHIFT;
1338
1339 while (iov_iter_count(i) > 0) {
1340 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1341 size_t write_bytes = min(iov_iter_count(i),
1342 nrptrs * (size_t)PAGE_CACHE_SIZE -
1343 offset);
1344 size_t num_pages = (write_bytes + offset +
1345 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1346 size_t dirty_pages;
1347 size_t copied;
1348
1349 WARN_ON(num_pages > nrptrs);
1350
1351 /*
1352 * Fault pages before locking them in prepare_pages
1353 * to avoid recursive lock
1354 */
1355 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1356 ret = -EFAULT;
1357 break;
1358 }
1359
1360 ret = btrfs_delalloc_reserve_space(inode,
1361 num_pages << PAGE_CACHE_SHIFT);
1362 if (ret)
1363 break;
1364
1365 /*
1366 * This is going to setup the pages array with the number of
1367 * pages we want, so we don't really need to worry about the
1368 * contents of pages from loop to loop
1369 */
1370 ret = prepare_pages(root, file, pages, num_pages,
1371 pos, first_index, write_bytes,
1372 force_page_uptodate);
1373 if (ret) {
1374 btrfs_delalloc_release_space(inode,
1375 num_pages << PAGE_CACHE_SHIFT);
1376 break;
1377 }
1378
1379 copied = btrfs_copy_from_user(pos, num_pages,
1380 write_bytes, pages, i);
1381
1382 /*
1383 * if we have trouble faulting in the pages, fall
1384 * back to one page at a time
1385 */
1386 if (copied < write_bytes)
1387 nrptrs = 1;
1388
1389 if (copied == 0) {
1390 force_page_uptodate = true;
1391 dirty_pages = 0;
1392 } else {
1393 force_page_uptodate = false;
1394 dirty_pages = (copied + offset +
1395 PAGE_CACHE_SIZE - 1) >>
1396 PAGE_CACHE_SHIFT;
1397 }
1398
1399 /*
1400 * If we had a short copy we need to release the excess delaloc
1401 * bytes we reserved. We need to increment outstanding_extents
1402 * because btrfs_delalloc_release_space will decrement it, but
1403 * we still have an outstanding extent for the chunk we actually
1404 * managed to copy.
1405 */
1406 if (num_pages > dirty_pages) {
1407 if (copied > 0) {
1408 spin_lock(&BTRFS_I(inode)->lock);
1409 BTRFS_I(inode)->outstanding_extents++;
1410 spin_unlock(&BTRFS_I(inode)->lock);
1411 }
1412 btrfs_delalloc_release_space(inode,
1413 (num_pages - dirty_pages) <<
1414 PAGE_CACHE_SHIFT);
1415 }
1416
1417 if (copied > 0) {
1418 ret = btrfs_dirty_pages(root, inode, pages,
1419 dirty_pages, pos, copied,
1420 NULL);
1421 if (ret) {
1422 btrfs_delalloc_release_space(inode,
1423 dirty_pages << PAGE_CACHE_SHIFT);
1424 btrfs_drop_pages(pages, num_pages);
1425 break;
1426 }
1427 }
1428
1429 btrfs_drop_pages(pages, num_pages);
1430
1431 cond_resched();
1432
1433 balance_dirty_pages_ratelimited(inode->i_mapping);
1434 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1435 btrfs_btree_balance_dirty(root);
1436
1437 pos += copied;
1438 num_written += copied;
1439 }
1440
1441 kfree(pages);
1442
1443 return num_written ? num_written : ret;
1444 }
1445
1446 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1447 const struct iovec *iov,
1448 unsigned long nr_segs, loff_t pos,
1449 loff_t *ppos, size_t count, size_t ocount)
1450 {
1451 struct file *file = iocb->ki_filp;
1452 struct iov_iter i;
1453 ssize_t written;
1454 ssize_t written_buffered;
1455 loff_t endbyte;
1456 int err;
1457
1458 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1459 count, ocount);
1460
1461 if (written < 0 || written == count)
1462 return written;
1463
1464 pos += written;
1465 count -= written;
1466 iov_iter_init(&i, iov, nr_segs, count, written);
1467 written_buffered = __btrfs_buffered_write(file, &i, pos);
1468 if (written_buffered < 0) {
1469 err = written_buffered;
1470 goto out;
1471 }
1472 endbyte = pos + written_buffered - 1;
1473 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1474 if (err)
1475 goto out;
1476 written += written_buffered;
1477 *ppos = pos + written_buffered;
1478 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1479 endbyte >> PAGE_CACHE_SHIFT);
1480 out:
1481 return written ? written : err;
1482 }
1483
1484 static void update_time_for_write(struct inode *inode)
1485 {
1486 struct timespec now;
1487
1488 if (IS_NOCMTIME(inode))
1489 return;
1490
1491 now = current_fs_time(inode->i_sb);
1492 if (!timespec_equal(&inode->i_mtime, &now))
1493 inode->i_mtime = now;
1494
1495 if (!timespec_equal(&inode->i_ctime, &now))
1496 inode->i_ctime = now;
1497
1498 if (IS_I_VERSION(inode))
1499 inode_inc_iversion(inode);
1500 }
1501
1502 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1503 const struct iovec *iov,
1504 unsigned long nr_segs, loff_t pos)
1505 {
1506 struct file *file = iocb->ki_filp;
1507 struct inode *inode = file_inode(file);
1508 struct btrfs_root *root = BTRFS_I(inode)->root;
1509 loff_t *ppos = &iocb->ki_pos;
1510 u64 start_pos;
1511 ssize_t num_written = 0;
1512 ssize_t err = 0;
1513 size_t count, ocount;
1514 bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
1515
1516 sb_start_write(inode->i_sb);
1517
1518 mutex_lock(&inode->i_mutex);
1519
1520 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1521 if (err) {
1522 mutex_unlock(&inode->i_mutex);
1523 goto out;
1524 }
1525 count = ocount;
1526
1527 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1528 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1529 if (err) {
1530 mutex_unlock(&inode->i_mutex);
1531 goto out;
1532 }
1533
1534 if (count == 0) {
1535 mutex_unlock(&inode->i_mutex);
1536 goto out;
1537 }
1538
1539 err = file_remove_suid(file);
1540 if (err) {
1541 mutex_unlock(&inode->i_mutex);
1542 goto out;
1543 }
1544
1545 /*
1546 * If BTRFS flips readonly due to some impossible error
1547 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1548 * although we have opened a file as writable, we have
1549 * to stop this write operation to ensure FS consistency.
1550 */
1551 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1552 mutex_unlock(&inode->i_mutex);
1553 err = -EROFS;
1554 goto out;
1555 }
1556
1557 /*
1558 * We reserve space for updating the inode when we reserve space for the
1559 * extent we are going to write, so we will enospc out there. We don't
1560 * need to start yet another transaction to update the inode as we will
1561 * update the inode when we finish writing whatever data we write.
1562 */
1563 update_time_for_write(inode);
1564
1565 start_pos = round_down(pos, root->sectorsize);
1566 if (start_pos > i_size_read(inode)) {
1567 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1568 if (err) {
1569 mutex_unlock(&inode->i_mutex);
1570 goto out;
1571 }
1572 }
1573
1574 if (sync)
1575 atomic_inc(&BTRFS_I(inode)->sync_writers);
1576
1577 if (unlikely(file->f_flags & O_DIRECT)) {
1578 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1579 pos, ppos, count, ocount);
1580 } else {
1581 struct iov_iter i;
1582
1583 iov_iter_init(&i, iov, nr_segs, count, num_written);
1584
1585 num_written = __btrfs_buffered_write(file, &i, pos);
1586 if (num_written > 0)
1587 *ppos = pos + num_written;
1588 }
1589
1590 mutex_unlock(&inode->i_mutex);
1591
1592 /*
1593 * we want to make sure fsync finds this change
1594 * but we haven't joined a transaction running right now.
1595 *
1596 * Later on, someone is sure to update the inode and get the
1597 * real transid recorded.
1598 *
1599 * We set last_trans now to the fs_info generation + 1,
1600 * this will either be one more than the running transaction
1601 * or the generation used for the next transaction if there isn't
1602 * one running right now.
1603 *
1604 * We also have to set last_sub_trans to the current log transid,
1605 * otherwise subsequent syncs to a file that's been synced in this
1606 * transaction will appear to have already occured.
1607 */
1608 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1609 BTRFS_I(inode)->last_sub_trans = root->log_transid;
1610 if (num_written > 0 || num_written == -EIOCBQUEUED) {
1611 err = generic_write_sync(file, pos, num_written);
1612 if (err < 0 && num_written > 0)
1613 num_written = err;
1614 }
1615
1616 if (sync)
1617 atomic_dec(&BTRFS_I(inode)->sync_writers);
1618 out:
1619 sb_end_write(inode->i_sb);
1620 current->backing_dev_info = NULL;
1621 return num_written ? num_written : err;
1622 }
1623
1624 int btrfs_release_file(struct inode *inode, struct file *filp)
1625 {
1626 /*
1627 * ordered_data_close is set by settattr when we are about to truncate
1628 * a file from a non-zero size to a zero size. This tries to
1629 * flush down new bytes that may have been written if the
1630 * application were using truncate to replace a file in place.
1631 */
1632 if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
1633 &BTRFS_I(inode)->runtime_flags)) {
1634 struct btrfs_trans_handle *trans;
1635 struct btrfs_root *root = BTRFS_I(inode)->root;
1636
1637 /*
1638 * We need to block on a committing transaction to keep us from
1639 * throwing a ordered operation on to the list and causing
1640 * something like sync to deadlock trying to flush out this
1641 * inode.
1642 */
1643 trans = btrfs_start_transaction(root, 0);
1644 if (IS_ERR(trans))
1645 return PTR_ERR(trans);
1646 btrfs_add_ordered_operation(trans, BTRFS_I(inode)->root, inode);
1647 btrfs_end_transaction(trans, root);
1648 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1649 filemap_flush(inode->i_mapping);
1650 }
1651 if (filp->private_data)
1652 btrfs_ioctl_trans_end(filp);
1653 return 0;
1654 }
1655
1656 /*
1657 * fsync call for both files and directories. This logs the inode into
1658 * the tree log instead of forcing full commits whenever possible.
1659 *
1660 * It needs to call filemap_fdatawait so that all ordered extent updates are
1661 * in the metadata btree are up to date for copying to the log.
1662 *
1663 * It drops the inode mutex before doing the tree log commit. This is an
1664 * important optimization for directories because holding the mutex prevents
1665 * new operations on the dir while we write to disk.
1666 */
1667 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1668 {
1669 struct dentry *dentry = file->f_path.dentry;
1670 struct inode *inode = dentry->d_inode;
1671 struct btrfs_root *root = BTRFS_I(inode)->root;
1672 int ret = 0;
1673 struct btrfs_trans_handle *trans;
1674 bool full_sync = 0;
1675
1676 trace_btrfs_sync_file(file, datasync);
1677
1678 /*
1679 * We write the dirty pages in the range and wait until they complete
1680 * out of the ->i_mutex. If so, we can flush the dirty pages by
1681 * multi-task, and make the performance up. See
1682 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1683 */
1684 atomic_inc(&BTRFS_I(inode)->sync_writers);
1685 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1686 if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1687 &BTRFS_I(inode)->runtime_flags))
1688 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1689 atomic_dec(&BTRFS_I(inode)->sync_writers);
1690 if (ret)
1691 return ret;
1692
1693 mutex_lock(&inode->i_mutex);
1694
1695 /*
1696 * We flush the dirty pages again to avoid some dirty pages in the
1697 * range being left.
1698 */
1699 atomic_inc(&root->log_batch);
1700 full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1701 &BTRFS_I(inode)->runtime_flags);
1702 if (full_sync)
1703 btrfs_wait_ordered_range(inode, start, end - start + 1);
1704 atomic_inc(&root->log_batch);
1705
1706 /*
1707 * check the transaction that last modified this inode
1708 * and see if its already been committed
1709 */
1710 if (!BTRFS_I(inode)->last_trans) {
1711 mutex_unlock(&inode->i_mutex);
1712 goto out;
1713 }
1714
1715 /*
1716 * if the last transaction that changed this file was before
1717 * the current transaction, we can bail out now without any
1718 * syncing
1719 */
1720 smp_mb();
1721 if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
1722 BTRFS_I(inode)->last_trans <=
1723 root->fs_info->last_trans_committed) {
1724 BTRFS_I(inode)->last_trans = 0;
1725
1726 /*
1727 * We'v had everything committed since the last time we were
1728 * modified so clear this flag in case it was set for whatever
1729 * reason, it's no longer relevant.
1730 */
1731 clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1732 &BTRFS_I(inode)->runtime_flags);
1733 mutex_unlock(&inode->i_mutex);
1734 goto out;
1735 }
1736
1737 /*
1738 * ok we haven't committed the transaction yet, lets do a commit
1739 */
1740 if (file->private_data)
1741 btrfs_ioctl_trans_end(file);
1742
1743 trans = btrfs_start_transaction(root, 0);
1744 if (IS_ERR(trans)) {
1745 ret = PTR_ERR(trans);
1746 mutex_unlock(&inode->i_mutex);
1747 goto out;
1748 }
1749
1750 ret = btrfs_log_dentry_safe(trans, root, dentry);
1751 if (ret < 0) {
1752 mutex_unlock(&inode->i_mutex);
1753 goto out;
1754 }
1755
1756 /* we've logged all the items and now have a consistent
1757 * version of the file in the log. It is possible that
1758 * someone will come in and modify the file, but that's
1759 * fine because the log is consistent on disk, and we
1760 * have references to all of the file's extents
1761 *
1762 * It is possible that someone will come in and log the
1763 * file again, but that will end up using the synchronization
1764 * inside btrfs_sync_log to keep things safe.
1765 */
1766 mutex_unlock(&inode->i_mutex);
1767
1768 if (ret != BTRFS_NO_LOG_SYNC) {
1769 if (ret > 0) {
1770 /*
1771 * If we didn't already wait for ordered extents we need
1772 * to do that now.
1773 */
1774 if (!full_sync)
1775 btrfs_wait_ordered_range(inode, start,
1776 end - start + 1);
1777 ret = btrfs_commit_transaction(trans, root);
1778 } else {
1779 ret = btrfs_sync_log(trans, root);
1780 if (ret == 0) {
1781 ret = btrfs_end_transaction(trans, root);
1782 } else {
1783 if (!full_sync)
1784 btrfs_wait_ordered_range(inode, start,
1785 end -
1786 start + 1);
1787 ret = btrfs_commit_transaction(trans, root);
1788 }
1789 }
1790 } else {
1791 ret = btrfs_end_transaction(trans, root);
1792 }
1793 out:
1794 return ret > 0 ? -EIO : ret;
1795 }
1796
1797 static const struct vm_operations_struct btrfs_file_vm_ops = {
1798 .fault = filemap_fault,
1799 .page_mkwrite = btrfs_page_mkwrite,
1800 .remap_pages = generic_file_remap_pages,
1801 };
1802
1803 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1804 {
1805 struct address_space *mapping = filp->f_mapping;
1806
1807 if (!mapping->a_ops->readpage)
1808 return -ENOEXEC;
1809
1810 file_accessed(filp);
1811 vma->vm_ops = &btrfs_file_vm_ops;
1812
1813 return 0;
1814 }
1815
1816 static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf,
1817 int slot, u64 start, u64 end)
1818 {
1819 struct btrfs_file_extent_item *fi;
1820 struct btrfs_key key;
1821
1822 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
1823 return 0;
1824
1825 btrfs_item_key_to_cpu(leaf, &key, slot);
1826 if (key.objectid != btrfs_ino(inode) ||
1827 key.type != BTRFS_EXTENT_DATA_KEY)
1828 return 0;
1829
1830 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1831
1832 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
1833 return 0;
1834
1835 if (btrfs_file_extent_disk_bytenr(leaf, fi))
1836 return 0;
1837
1838 if (key.offset == end)
1839 return 1;
1840 if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
1841 return 1;
1842 return 0;
1843 }
1844
1845 static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
1846 struct btrfs_path *path, u64 offset, u64 end)
1847 {
1848 struct btrfs_root *root = BTRFS_I(inode)->root;
1849 struct extent_buffer *leaf;
1850 struct btrfs_file_extent_item *fi;
1851 struct extent_map *hole_em;
1852 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1853 struct btrfs_key key;
1854 int ret;
1855
1856 key.objectid = btrfs_ino(inode);
1857 key.type = BTRFS_EXTENT_DATA_KEY;
1858 key.offset = offset;
1859
1860
1861 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1862 if (ret < 0)
1863 return ret;
1864 BUG_ON(!ret);
1865
1866 leaf = path->nodes[0];
1867 if (hole_mergeable(inode, leaf, path->slots[0]-1, offset, end)) {
1868 u64 num_bytes;
1869
1870 path->slots[0]--;
1871 fi = btrfs_item_ptr(leaf, path->slots[0],
1872 struct btrfs_file_extent_item);
1873 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
1874 end - offset;
1875 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1876 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
1877 btrfs_set_file_extent_offset(leaf, fi, 0);
1878 btrfs_mark_buffer_dirty(leaf);
1879 goto out;
1880 }
1881
1882 if (hole_mergeable(inode, leaf, path->slots[0]+1, offset, end)) {
1883 u64 num_bytes;
1884
1885 path->slots[0]++;
1886 key.offset = offset;
1887 btrfs_set_item_key_safe(root, path, &key);
1888 fi = btrfs_item_ptr(leaf, path->slots[0],
1889 struct btrfs_file_extent_item);
1890 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
1891 offset;
1892 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1893 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
1894 btrfs_set_file_extent_offset(leaf, fi, 0);
1895 btrfs_mark_buffer_dirty(leaf);
1896 goto out;
1897 }
1898 btrfs_release_path(path);
1899
1900 ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
1901 0, 0, end - offset, 0, end - offset,
1902 0, 0, 0);
1903 if (ret)
1904 return ret;
1905
1906 out:
1907 btrfs_release_path(path);
1908
1909 hole_em = alloc_extent_map();
1910 if (!hole_em) {
1911 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
1912 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1913 &BTRFS_I(inode)->runtime_flags);
1914 } else {
1915 hole_em->start = offset;
1916 hole_em->len = end - offset;
1917 hole_em->ram_bytes = hole_em->len;
1918 hole_em->orig_start = offset;
1919
1920 hole_em->block_start = EXTENT_MAP_HOLE;
1921 hole_em->block_len = 0;
1922 hole_em->orig_block_len = 0;
1923 hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
1924 hole_em->compress_type = BTRFS_COMPRESS_NONE;
1925 hole_em->generation = trans->transid;
1926
1927 do {
1928 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
1929 write_lock(&em_tree->lock);
1930 ret = add_extent_mapping(em_tree, hole_em, 1);
1931 write_unlock(&em_tree->lock);
1932 } while (ret == -EEXIST);
1933 free_extent_map(hole_em);
1934 if (ret)
1935 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1936 &BTRFS_I(inode)->runtime_flags);
1937 }
1938
1939 return 0;
1940 }
1941
1942 static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
1943 {
1944 struct btrfs_root *root = BTRFS_I(inode)->root;
1945 struct extent_state *cached_state = NULL;
1946 struct btrfs_path *path;
1947 struct btrfs_block_rsv *rsv;
1948 struct btrfs_trans_handle *trans;
1949 u64 lockstart = round_up(offset, BTRFS_I(inode)->root->sectorsize);
1950 u64 lockend = round_down(offset + len,
1951 BTRFS_I(inode)->root->sectorsize) - 1;
1952 u64 cur_offset = lockstart;
1953 u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
1954 u64 drop_end;
1955 int ret = 0;
1956 int err = 0;
1957 bool same_page = ((offset >> PAGE_CACHE_SHIFT) ==
1958 ((offset + len - 1) >> PAGE_CACHE_SHIFT));
1959
1960 btrfs_wait_ordered_range(inode, offset, len);
1961
1962 mutex_lock(&inode->i_mutex);
1963 /*
1964 * We needn't truncate any page which is beyond the end of the file
1965 * because we are sure there is no data there.
1966 */
1967 /*
1968 * Only do this if we are in the same page and we aren't doing the
1969 * entire page.
1970 */
1971 if (same_page && len < PAGE_CACHE_SIZE) {
1972 if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE))
1973 ret = btrfs_truncate_page(inode, offset, len, 0);
1974 mutex_unlock(&inode->i_mutex);
1975 return ret;
1976 }
1977
1978 /* zero back part of the first page */
1979 if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
1980 ret = btrfs_truncate_page(inode, offset, 0, 0);
1981 if (ret) {
1982 mutex_unlock(&inode->i_mutex);
1983 return ret;
1984 }
1985 }
1986
1987 /* zero the front end of the last page */
1988 if (offset + len < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
1989 ret = btrfs_truncate_page(inode, offset + len, 0, 1);
1990 if (ret) {
1991 mutex_unlock(&inode->i_mutex);
1992 return ret;
1993 }
1994 }
1995
1996 if (lockend < lockstart) {
1997 mutex_unlock(&inode->i_mutex);
1998 return 0;
1999 }
2000
2001 while (1) {
2002 struct btrfs_ordered_extent *ordered;
2003
2004 truncate_pagecache_range(inode, lockstart, lockend);
2005
2006 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2007 0, &cached_state);
2008 ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
2009
2010 /*
2011 * We need to make sure we have no ordered extents in this range
2012 * and nobody raced in and read a page in this range, if we did
2013 * we need to try again.
2014 */
2015 if ((!ordered ||
2016 (ordered->file_offset + ordered->len < lockstart ||
2017 ordered->file_offset > lockend)) &&
2018 !test_range_bit(&BTRFS_I(inode)->io_tree, lockstart,
2019 lockend, EXTENT_UPTODATE, 0,
2020 cached_state)) {
2021 if (ordered)
2022 btrfs_put_ordered_extent(ordered);
2023 break;
2024 }
2025 if (ordered)
2026 btrfs_put_ordered_extent(ordered);
2027 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
2028 lockend, &cached_state, GFP_NOFS);
2029 btrfs_wait_ordered_range(inode, lockstart,
2030 lockend - lockstart + 1);
2031 }
2032
2033 path = btrfs_alloc_path();
2034 if (!path) {
2035 ret = -ENOMEM;
2036 goto out;
2037 }
2038
2039 rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2040 if (!rsv) {
2041 ret = -ENOMEM;
2042 goto out_free;
2043 }
2044 rsv->size = btrfs_calc_trunc_metadata_size(root, 1);
2045 rsv->failfast = 1;
2046
2047 /*
2048 * 1 - update the inode
2049 * 1 - removing the extents in the range
2050 * 1 - adding the hole extent
2051 */
2052 trans = btrfs_start_transaction(root, 3);
2053 if (IS_ERR(trans)) {
2054 err = PTR_ERR(trans);
2055 goto out_free;
2056 }
2057
2058 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
2059 min_size);
2060 BUG_ON(ret);
2061 trans->block_rsv = rsv;
2062
2063 while (cur_offset < lockend) {
2064 ret = __btrfs_drop_extents(trans, root, inode, path,
2065 cur_offset, lockend + 1,
2066 &drop_end, 1);
2067 if (ret != -ENOSPC)
2068 break;
2069
2070 trans->block_rsv = &root->fs_info->trans_block_rsv;
2071
2072 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2073 if (ret) {
2074 err = ret;
2075 break;
2076 }
2077
2078 cur_offset = drop_end;
2079
2080 ret = btrfs_update_inode(trans, root, inode);
2081 if (ret) {
2082 err = ret;
2083 break;
2084 }
2085
2086 btrfs_end_transaction(trans, root);
2087 btrfs_btree_balance_dirty(root);
2088
2089 trans = btrfs_start_transaction(root, 3);
2090 if (IS_ERR(trans)) {
2091 ret = PTR_ERR(trans);
2092 trans = NULL;
2093 break;
2094 }
2095
2096 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
2097 rsv, min_size);
2098 BUG_ON(ret); /* shouldn't happen */
2099 trans->block_rsv = rsv;
2100 }
2101
2102 if (ret) {
2103 err = ret;
2104 goto out_trans;
2105 }
2106
2107 trans->block_rsv = &root->fs_info->trans_block_rsv;
2108 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2109 if (ret) {
2110 err = ret;
2111 goto out_trans;
2112 }
2113
2114 out_trans:
2115 if (!trans)
2116 goto out_free;
2117
2118 inode_inc_iversion(inode);
2119 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
2120
2121 trans->block_rsv = &root->fs_info->trans_block_rsv;
2122 ret = btrfs_update_inode(trans, root, inode);
2123 btrfs_end_transaction(trans, root);
2124 btrfs_btree_balance_dirty(root);
2125 out_free:
2126 btrfs_free_path(path);
2127 btrfs_free_block_rsv(root, rsv);
2128 out:
2129 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2130 &cached_state, GFP_NOFS);
2131 mutex_unlock(&inode->i_mutex);
2132 if (ret && !err)
2133 err = ret;
2134 return err;
2135 }
2136
2137 static long btrfs_fallocate(struct file *file, int mode,
2138 loff_t offset, loff_t len)
2139 {
2140 struct inode *inode = file_inode(file);
2141 struct extent_state *cached_state = NULL;
2142 struct btrfs_root *root = BTRFS_I(inode)->root;
2143 u64 cur_offset;
2144 u64 last_byte;
2145 u64 alloc_start;
2146 u64 alloc_end;
2147 u64 alloc_hint = 0;
2148 u64 locked_end;
2149 struct extent_map *em;
2150 int blocksize = BTRFS_I(inode)->root->sectorsize;
2151 int ret;
2152
2153 alloc_start = round_down(offset, blocksize);
2154 alloc_end = round_up(offset + len, blocksize);
2155
2156 /* Make sure we aren't being give some crap mode */
2157 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2158 return -EOPNOTSUPP;
2159
2160 if (mode & FALLOC_FL_PUNCH_HOLE)
2161 return btrfs_punch_hole(inode, offset, len);
2162
2163 /*
2164 * Make sure we have enough space before we do the
2165 * allocation.
2166 */
2167 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
2168 if (ret)
2169 return ret;
2170 if (root->fs_info->quota_enabled) {
2171 ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
2172 if (ret)
2173 goto out_reserve_fail;
2174 }
2175
2176 mutex_lock(&inode->i_mutex);
2177 ret = inode_newsize_ok(inode, alloc_end);
2178 if (ret)
2179 goto out;
2180
2181 if (alloc_start > inode->i_size) {
2182 ret = btrfs_cont_expand(inode, i_size_read(inode),
2183 alloc_start);
2184 if (ret)
2185 goto out;
2186 } else {
2187 /*
2188 * If we are fallocating from the end of the file onward we
2189 * need to zero out the end of the page if i_size lands in the
2190 * middle of a page.
2191 */
2192 ret = btrfs_truncate_page(inode, inode->i_size, 0, 0);
2193 if (ret)
2194 goto out;
2195 }
2196
2197 /*
2198 * wait for ordered IO before we have any locks. We'll loop again
2199 * below with the locks held.
2200 */
2201 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
2202
2203 locked_end = alloc_end - 1;
2204 while (1) {
2205 struct btrfs_ordered_extent *ordered;
2206
2207 /* the extent lock is ordered inside the running
2208 * transaction
2209 */
2210 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
2211 locked_end, 0, &cached_state);
2212 ordered = btrfs_lookup_first_ordered_extent(inode,
2213 alloc_end - 1);
2214 if (ordered &&
2215 ordered->file_offset + ordered->len > alloc_start &&
2216 ordered->file_offset < alloc_end) {
2217 btrfs_put_ordered_extent(ordered);
2218 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
2219 alloc_start, locked_end,
2220 &cached_state, GFP_NOFS);
2221 /*
2222 * we can't wait on the range with the transaction
2223 * running or with the extent lock held
2224 */
2225 btrfs_wait_ordered_range(inode, alloc_start,
2226 alloc_end - alloc_start);
2227 } else {
2228 if (ordered)
2229 btrfs_put_ordered_extent(ordered);
2230 break;
2231 }
2232 }
2233
2234 cur_offset = alloc_start;
2235 while (1) {
2236 u64 actual_end;
2237
2238 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
2239 alloc_end - cur_offset, 0);
2240 if (IS_ERR_OR_NULL(em)) {
2241 if (!em)
2242 ret = -ENOMEM;
2243 else
2244 ret = PTR_ERR(em);
2245 break;
2246 }
2247 last_byte = min(extent_map_end(em), alloc_end);
2248 actual_end = min_t(u64, extent_map_end(em), offset + len);
2249 last_byte = ALIGN(last_byte, blocksize);
2250
2251 if (em->block_start == EXTENT_MAP_HOLE ||
2252 (cur_offset >= inode->i_size &&
2253 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
2254 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
2255 last_byte - cur_offset,
2256 1 << inode->i_blkbits,
2257 offset + len,
2258 &alloc_hint);
2259
2260 if (ret < 0) {
2261 free_extent_map(em);
2262 break;
2263 }
2264 } else if (actual_end > inode->i_size &&
2265 !(mode & FALLOC_FL_KEEP_SIZE)) {
2266 /*
2267 * We didn't need to allocate any more space, but we
2268 * still extended the size of the file so we need to
2269 * update i_size.
2270 */
2271 inode->i_ctime = CURRENT_TIME;
2272 i_size_write(inode, actual_end);
2273 btrfs_ordered_update_i_size(inode, actual_end, NULL);
2274 }
2275 free_extent_map(em);
2276
2277 cur_offset = last_byte;
2278 if (cur_offset >= alloc_end) {
2279 ret = 0;
2280 break;
2281 }
2282 }
2283 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
2284 &cached_state, GFP_NOFS);
2285 out:
2286 mutex_unlock(&inode->i_mutex);
2287 if (root->fs_info->quota_enabled)
2288 btrfs_qgroup_free(root, alloc_end - alloc_start);
2289 out_reserve_fail:
2290 /* Let go of our reservation. */
2291 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
2292 return ret;
2293 }
2294
2295 static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
2296 {
2297 struct btrfs_root *root = BTRFS_I(inode)->root;
2298 struct extent_map *em;
2299 struct extent_state *cached_state = NULL;
2300 u64 lockstart = *offset;
2301 u64 lockend = i_size_read(inode);
2302 u64 start = *offset;
2303 u64 orig_start = *offset;
2304 u64 len = i_size_read(inode);
2305 u64 last_end = 0;
2306 int ret = 0;
2307
2308 lockend = max_t(u64, root->sectorsize, lockend);
2309 if (lockend <= lockstart)
2310 lockend = lockstart + root->sectorsize;
2311
2312 lockend--;
2313 len = lockend - lockstart + 1;
2314
2315 len = max_t(u64, len, root->sectorsize);
2316 if (inode->i_size == 0)
2317 return -ENXIO;
2318
2319 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
2320 &cached_state);
2321
2322 /*
2323 * Delalloc is such a pain. If we have a hole and we have pending
2324 * delalloc for a portion of the hole we will get back a hole that
2325 * exists for the entire range since it hasn't been actually written
2326 * yet. So to take care of this case we need to look for an extent just
2327 * before the position we want in case there is outstanding delalloc
2328 * going on here.
2329 */
2330 if (whence == SEEK_HOLE && start != 0) {
2331 if (start <= root->sectorsize)
2332 em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
2333 root->sectorsize, 0);
2334 else
2335 em = btrfs_get_extent_fiemap(inode, NULL, 0,
2336 start - root->sectorsize,
2337 root->sectorsize, 0);
2338 if (IS_ERR(em)) {
2339 ret = PTR_ERR(em);
2340 goto out;
2341 }
2342 last_end = em->start + em->len;
2343 if (em->block_start == EXTENT_MAP_DELALLOC)
2344 last_end = min_t(u64, last_end, inode->i_size);
2345 free_extent_map(em);
2346 }
2347
2348 while (1) {
2349 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
2350 if (IS_ERR(em)) {
2351 ret = PTR_ERR(em);
2352 break;
2353 }
2354
2355 if (em->block_start == EXTENT_MAP_HOLE) {
2356 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
2357 if (last_end <= orig_start) {
2358 free_extent_map(em);
2359 ret = -ENXIO;
2360 break;
2361 }
2362 }
2363
2364 if (whence == SEEK_HOLE) {
2365 *offset = start;
2366 free_extent_map(em);
2367 break;
2368 }
2369 } else {
2370 if (whence == SEEK_DATA) {
2371 if (em->block_start == EXTENT_MAP_DELALLOC) {
2372 if (start >= inode->i_size) {
2373 free_extent_map(em);
2374 ret = -ENXIO;
2375 break;
2376 }
2377 }
2378
2379 if (!test_bit(EXTENT_FLAG_PREALLOC,
2380 &em->flags)) {
2381 *offset = start;
2382 free_extent_map(em);
2383 break;
2384 }
2385 }
2386 }
2387
2388 start = em->start + em->len;
2389 last_end = em->start + em->len;
2390
2391 if (em->block_start == EXTENT_MAP_DELALLOC)
2392 last_end = min_t(u64, last_end, inode->i_size);
2393
2394 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
2395 free_extent_map(em);
2396 ret = -ENXIO;
2397 break;
2398 }
2399 free_extent_map(em);
2400 cond_resched();
2401 }
2402 if (!ret)
2403 *offset = min(*offset, inode->i_size);
2404 out:
2405 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2406 &cached_state, GFP_NOFS);
2407 return ret;
2408 }
2409
2410 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
2411 {
2412 struct inode *inode = file->f_mapping->host;
2413 int ret;
2414
2415 mutex_lock(&inode->i_mutex);
2416 switch (whence) {
2417 case SEEK_END:
2418 case SEEK_CUR:
2419 offset = generic_file_llseek(file, offset, whence);
2420 goto out;
2421 case SEEK_DATA:
2422 case SEEK_HOLE:
2423 if (offset >= i_size_read(inode)) {
2424 mutex_unlock(&inode->i_mutex);
2425 return -ENXIO;
2426 }
2427
2428 ret = find_desired_extent(inode, &offset, whence);
2429 if (ret) {
2430 mutex_unlock(&inode->i_mutex);
2431 return ret;
2432 }
2433 }
2434
2435 if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
2436 offset = -EINVAL;
2437 goto out;
2438 }
2439 if (offset > inode->i_sb->s_maxbytes) {
2440 offset = -EINVAL;
2441 goto out;
2442 }
2443
2444 /* Special lock needed here? */
2445 if (offset != file->f_pos) {
2446 file->f_pos = offset;
2447 file->f_version = 0;
2448 }
2449 out:
2450 mutex_unlock(&inode->i_mutex);
2451 return offset;
2452 }
2453
2454 const struct file_operations btrfs_file_operations = {
2455 .llseek = btrfs_file_llseek,
2456 .read = do_sync_read,
2457 .write = do_sync_write,
2458 .aio_read = generic_file_aio_read,
2459 .splice_read = generic_file_splice_read,
2460 .aio_write = btrfs_file_aio_write,
2461 .mmap = btrfs_file_mmap,
2462 .open = generic_file_open,
2463 .release = btrfs_release_file,
2464 .fsync = btrfs_sync_file,
2465 .fallocate = btrfs_fallocate,
2466 .unlocked_ioctl = btrfs_ioctl,
2467 #ifdef CONFIG_COMPAT
2468 .compat_ioctl = btrfs_ioctl,
2469 #endif
2470 };
2471
2472 void btrfs_auto_defrag_exit(void)
2473 {
2474 if (btrfs_inode_defrag_cachep)
2475 kmem_cache_destroy(btrfs_inode_defrag_cachep);
2476 }
2477
2478 int btrfs_auto_defrag_init(void)
2479 {
2480 btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
2481 sizeof(struct inode_defrag), 0,
2482 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
2483 NULL);
2484 if (!btrfs_inode_defrag_cachep)
2485 return -ENOMEM;
2486
2487 return 0;
2488 }
Linux kernel - Deliverables
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