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