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Btrfs: add a priority queue to the async thread helpers
[mirror_ubuntu-bionic-kernel.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/smp_lock.h>
26 #include <linux/backing-dev.h>
27 #include <linux/mpage.h>
28 #include <linux/swap.h>
29 #include <linux/writeback.h>
30 #include <linux/statfs.h>
31 #include <linux/compat.h>
32 #include "ctree.h"
33 #include "disk-io.h"
34 #include "transaction.h"
35 #include "btrfs_inode.h"
36 #include "ioctl.h"
37 #include "print-tree.h"
38 #include "tree-log.h"
39 #include "locking.h"
40 #include "compat.h"
41
42
43 /* simple helper to fault in pages and copy. This should go away
44 * and be replaced with calls into generic code.
45 */
46 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
47 int write_bytes,
48 struct page **prepared_pages,
49 const char __user *buf)
50 {
51 long page_fault = 0;
52 int i;
53 int offset = pos & (PAGE_CACHE_SIZE - 1);
54
55 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
56 size_t count = min_t(size_t,
57 PAGE_CACHE_SIZE - offset, write_bytes);
58 struct page *page = prepared_pages[i];
59 fault_in_pages_readable(buf, count);
60
61 /* Copy data from userspace to the current page */
62 kmap(page);
63 page_fault = __copy_from_user(page_address(page) + offset,
64 buf, count);
65 /* Flush processor's dcache for this page */
66 flush_dcache_page(page);
67 kunmap(page);
68 buf += count;
69 write_bytes -= count;
70
71 if (page_fault)
72 break;
73 }
74 return page_fault ? -EFAULT : 0;
75 }
76
77 /*
78 * unlocks pages after btrfs_file_write is done with them
79 */
80 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
81 {
82 size_t i;
83 for (i = 0; i < num_pages; i++) {
84 if (!pages[i])
85 break;
86 /* page checked is some magic around finding pages that
87 * have been modified without going through btrfs_set_page_dirty
88 * clear it here
89 */
90 ClearPageChecked(pages[i]);
91 unlock_page(pages[i]);
92 mark_page_accessed(pages[i]);
93 page_cache_release(pages[i]);
94 }
95 }
96
97 /*
98 * after copy_from_user, pages need to be dirtied and we need to make
99 * sure holes are created between the current EOF and the start of
100 * any next extents (if required).
101 *
102 * this also makes the decision about creating an inline extent vs
103 * doing real data extents, marking pages dirty and delalloc as required.
104 */
105 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
106 struct btrfs_root *root,
107 struct file *file,
108 struct page **pages,
109 size_t num_pages,
110 loff_t pos,
111 size_t write_bytes)
112 {
113 int err = 0;
114 int i;
115 struct inode *inode = fdentry(file)->d_inode;
116 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
117 u64 hint_byte;
118 u64 num_bytes;
119 u64 start_pos;
120 u64 end_of_last_block;
121 u64 end_pos = pos + write_bytes;
122 loff_t isize = i_size_read(inode);
123
124 start_pos = pos & ~((u64)root->sectorsize - 1);
125 num_bytes = (write_bytes + pos - start_pos +
126 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
127
128 end_of_last_block = start_pos + num_bytes - 1;
129
130 lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
131 trans = btrfs_join_transaction(root, 1);
132 if (!trans) {
133 err = -ENOMEM;
134 goto out_unlock;
135 }
136 btrfs_set_trans_block_group(trans, inode);
137 hint_byte = 0;
138
139 set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
140
141 /* check for reserved extents on each page, we don't want
142 * to reset the delalloc bit on things that already have
143 * extents reserved.
144 */
145 btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
146 for (i = 0; i < num_pages; i++) {
147 struct page *p = pages[i];
148 SetPageUptodate(p);
149 ClearPageChecked(p);
150 set_page_dirty(p);
151 }
152 if (end_pos > isize) {
153 i_size_write(inode, end_pos);
154 btrfs_update_inode(trans, root, inode);
155 }
156 err = btrfs_end_transaction(trans, root);
157 out_unlock:
158 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
159 return err;
160 }
161
162 /*
163 * this drops all the extents in the cache that intersect the range
164 * [start, end]. Existing extents are split as required.
165 */
166 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
167 int skip_pinned)
168 {
169 struct extent_map *em;
170 struct extent_map *split = NULL;
171 struct extent_map *split2 = NULL;
172 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
173 u64 len = end - start + 1;
174 int ret;
175 int testend = 1;
176 unsigned long flags;
177 int compressed = 0;
178
179 WARN_ON(end < start);
180 if (end == (u64)-1) {
181 len = (u64)-1;
182 testend = 0;
183 }
184 while (1) {
185 if (!split)
186 split = alloc_extent_map(GFP_NOFS);
187 if (!split2)
188 split2 = alloc_extent_map(GFP_NOFS);
189
190 spin_lock(&em_tree->lock);
191 em = lookup_extent_mapping(em_tree, start, len);
192 if (!em) {
193 spin_unlock(&em_tree->lock);
194 break;
195 }
196 flags = em->flags;
197 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
198 spin_unlock(&em_tree->lock);
199 if (em->start <= start &&
200 (!testend || em->start + em->len >= start + len)) {
201 free_extent_map(em);
202 break;
203 }
204 if (start < em->start) {
205 len = em->start - start;
206 } else {
207 len = start + len - (em->start + em->len);
208 start = em->start + em->len;
209 }
210 free_extent_map(em);
211 continue;
212 }
213 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
214 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
215 remove_extent_mapping(em_tree, em);
216
217 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
218 em->start < start) {
219 split->start = em->start;
220 split->len = start - em->start;
221 split->orig_start = em->orig_start;
222 split->block_start = em->block_start;
223
224 if (compressed)
225 split->block_len = em->block_len;
226 else
227 split->block_len = split->len;
228
229 split->bdev = em->bdev;
230 split->flags = flags;
231 ret = add_extent_mapping(em_tree, split);
232 BUG_ON(ret);
233 free_extent_map(split);
234 split = split2;
235 split2 = NULL;
236 }
237 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
238 testend && em->start + em->len > start + len) {
239 u64 diff = start + len - em->start;
240
241 split->start = start + len;
242 split->len = em->start + em->len - (start + len);
243 split->bdev = em->bdev;
244 split->flags = flags;
245
246 if (compressed) {
247 split->block_len = em->block_len;
248 split->block_start = em->block_start;
249 split->orig_start = em->orig_start;
250 } else {
251 split->block_len = split->len;
252 split->block_start = em->block_start + diff;
253 split->orig_start = split->start;
254 }
255
256 ret = add_extent_mapping(em_tree, split);
257 BUG_ON(ret);
258 free_extent_map(split);
259 split = NULL;
260 }
261 spin_unlock(&em_tree->lock);
262
263 /* once for us */
264 free_extent_map(em);
265 /* once for the tree*/
266 free_extent_map(em);
267 }
268 if (split)
269 free_extent_map(split);
270 if (split2)
271 free_extent_map(split2);
272 return 0;
273 }
274
275 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
276 {
277 return 0;
278 #if 0
279 struct btrfs_path *path;
280 struct btrfs_key found_key;
281 struct extent_buffer *leaf;
282 struct btrfs_file_extent_item *extent;
283 u64 last_offset = 0;
284 int nritems;
285 int slot;
286 int found_type;
287 int ret;
288 int err = 0;
289 u64 extent_end = 0;
290
291 path = btrfs_alloc_path();
292 ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
293 last_offset, 0);
294 while (1) {
295 nritems = btrfs_header_nritems(path->nodes[0]);
296 if (path->slots[0] >= nritems) {
297 ret = btrfs_next_leaf(root, path);
298 if (ret)
299 goto out;
300 nritems = btrfs_header_nritems(path->nodes[0]);
301 }
302 slot = path->slots[0];
303 leaf = path->nodes[0];
304 btrfs_item_key_to_cpu(leaf, &found_key, slot);
305 if (found_key.objectid != inode->i_ino)
306 break;
307 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
308 goto out;
309
310 if (found_key.offset < last_offset) {
311 WARN_ON(1);
312 btrfs_print_leaf(root, leaf);
313 printk(KERN_ERR "inode %lu found offset %llu "
314 "expected %llu\n", inode->i_ino,
315 (unsigned long long)found_key.offset,
316 (unsigned long long)last_offset);
317 err = 1;
318 goto out;
319 }
320 extent = btrfs_item_ptr(leaf, slot,
321 struct btrfs_file_extent_item);
322 found_type = btrfs_file_extent_type(leaf, extent);
323 if (found_type == BTRFS_FILE_EXTENT_REG) {
324 extent_end = found_key.offset +
325 btrfs_file_extent_num_bytes(leaf, extent);
326 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
327 struct btrfs_item *item;
328 item = btrfs_item_nr(leaf, slot);
329 extent_end = found_key.offset +
330 btrfs_file_extent_inline_len(leaf, extent);
331 extent_end = (extent_end + root->sectorsize - 1) &
332 ~((u64)root->sectorsize - 1);
333 }
334 last_offset = extent_end;
335 path->slots[0]++;
336 }
337 if (0 && last_offset < inode->i_size) {
338 WARN_ON(1);
339 btrfs_print_leaf(root, leaf);
340 printk(KERN_ERR "inode %lu found offset %llu size %llu\n",
341 inode->i_ino, (unsigned long long)last_offset,
342 (unsigned long long)inode->i_size);
343 err = 1;
344
345 }
346 out:
347 btrfs_free_path(path);
348 return err;
349 #endif
350 }
351
352 /*
353 * this is very complex, but the basic idea is to drop all extents
354 * in the range start - end. hint_block is filled in with a block number
355 * that would be a good hint to the block allocator for this file.
356 *
357 * If an extent intersects the range but is not entirely inside the range
358 * it is either truncated or split. Anything entirely inside the range
359 * is deleted from the tree.
360 *
361 * inline_limit is used to tell this code which offsets in the file to keep
362 * if they contain inline extents.
363 */
364 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
365 struct btrfs_root *root, struct inode *inode,
366 u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
367 {
368 u64 extent_end = 0;
369 u64 locked_end = end;
370 u64 search_start = start;
371 u64 leaf_start;
372 u64 ram_bytes = 0;
373 u64 orig_parent = 0;
374 u64 disk_bytenr = 0;
375 u8 compression;
376 u8 encryption;
377 u16 other_encoding = 0;
378 u64 root_gen;
379 u64 root_owner;
380 struct extent_buffer *leaf;
381 struct btrfs_file_extent_item *extent;
382 struct btrfs_path *path;
383 struct btrfs_key key;
384 struct btrfs_file_extent_item old;
385 int keep;
386 int slot;
387 int bookend;
388 int found_type = 0;
389 int found_extent;
390 int found_inline;
391 int recow;
392 int ret;
393
394 inline_limit = 0;
395 btrfs_drop_extent_cache(inode, start, end - 1, 0);
396
397 path = btrfs_alloc_path();
398 if (!path)
399 return -ENOMEM;
400 while (1) {
401 recow = 0;
402 btrfs_release_path(root, path);
403 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
404 search_start, -1);
405 if (ret < 0)
406 goto out;
407 if (ret > 0) {
408 if (path->slots[0] == 0) {
409 ret = 0;
410 goto out;
411 }
412 path->slots[0]--;
413 }
414 next_slot:
415 keep = 0;
416 bookend = 0;
417 found_extent = 0;
418 found_inline = 0;
419 leaf_start = 0;
420 root_gen = 0;
421 root_owner = 0;
422 compression = 0;
423 encryption = 0;
424 extent = NULL;
425 leaf = path->nodes[0];
426 slot = path->slots[0];
427 ret = 0;
428 btrfs_item_key_to_cpu(leaf, &key, slot);
429 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
430 key.offset >= end) {
431 goto out;
432 }
433 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
434 key.objectid != inode->i_ino) {
435 goto out;
436 }
437 if (recow) {
438 search_start = max(key.offset, start);
439 continue;
440 }
441 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
442 extent = btrfs_item_ptr(leaf, slot,
443 struct btrfs_file_extent_item);
444 found_type = btrfs_file_extent_type(leaf, extent);
445 compression = btrfs_file_extent_compression(leaf,
446 extent);
447 encryption = btrfs_file_extent_encryption(leaf,
448 extent);
449 other_encoding = btrfs_file_extent_other_encoding(leaf,
450 extent);
451 if (found_type == BTRFS_FILE_EXTENT_REG ||
452 found_type == BTRFS_FILE_EXTENT_PREALLOC) {
453 extent_end =
454 btrfs_file_extent_disk_bytenr(leaf,
455 extent);
456 if (extent_end)
457 *hint_byte = extent_end;
458
459 extent_end = key.offset +
460 btrfs_file_extent_num_bytes(leaf, extent);
461 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
462 extent);
463 found_extent = 1;
464 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
465 found_inline = 1;
466 extent_end = key.offset +
467 btrfs_file_extent_inline_len(leaf, extent);
468 }
469 } else {
470 extent_end = search_start;
471 }
472
473 /* we found nothing we can drop */
474 if ((!found_extent && !found_inline) ||
475 search_start >= extent_end) {
476 int nextret;
477 u32 nritems;
478 nritems = btrfs_header_nritems(leaf);
479 if (slot >= nritems - 1) {
480 nextret = btrfs_next_leaf(root, path);
481 if (nextret)
482 goto out;
483 recow = 1;
484 } else {
485 path->slots[0]++;
486 }
487 goto next_slot;
488 }
489
490 if (end <= extent_end && start >= key.offset && found_inline)
491 *hint_byte = EXTENT_MAP_INLINE;
492
493 if (found_extent) {
494 read_extent_buffer(leaf, &old, (unsigned long)extent,
495 sizeof(old));
496 root_gen = btrfs_header_generation(leaf);
497 root_owner = btrfs_header_owner(leaf);
498 leaf_start = leaf->start;
499 }
500
501 if (end < extent_end && end >= key.offset) {
502 bookend = 1;
503 if (found_inline && start <= key.offset)
504 keep = 1;
505 }
506
507 if (bookend && found_extent) {
508 if (locked_end < extent_end) {
509 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
510 locked_end, extent_end - 1,
511 GFP_NOFS);
512 if (!ret) {
513 btrfs_release_path(root, path);
514 lock_extent(&BTRFS_I(inode)->io_tree,
515 locked_end, extent_end - 1,
516 GFP_NOFS);
517 locked_end = extent_end;
518 continue;
519 }
520 locked_end = extent_end;
521 }
522 orig_parent = path->nodes[0]->start;
523 disk_bytenr = le64_to_cpu(old.disk_bytenr);
524 if (disk_bytenr != 0) {
525 ret = btrfs_inc_extent_ref(trans, root,
526 disk_bytenr,
527 le64_to_cpu(old.disk_num_bytes),
528 orig_parent, root->root_key.objectid,
529 trans->transid, inode->i_ino);
530 BUG_ON(ret);
531 }
532 }
533
534 if (found_inline) {
535 u64 mask = root->sectorsize - 1;
536 search_start = (extent_end + mask) & ~mask;
537 } else
538 search_start = extent_end;
539
540 /* truncate existing extent */
541 if (start > key.offset) {
542 u64 new_num;
543 u64 old_num;
544 keep = 1;
545 WARN_ON(start & (root->sectorsize - 1));
546 if (found_extent) {
547 new_num = start - key.offset;
548 old_num = btrfs_file_extent_num_bytes(leaf,
549 extent);
550 *hint_byte =
551 btrfs_file_extent_disk_bytenr(leaf,
552 extent);
553 if (btrfs_file_extent_disk_bytenr(leaf,
554 extent)) {
555 inode_sub_bytes(inode, old_num -
556 new_num);
557 }
558 btrfs_set_file_extent_num_bytes(leaf,
559 extent, new_num);
560 btrfs_mark_buffer_dirty(leaf);
561 } else if (key.offset < inline_limit &&
562 (end > extent_end) &&
563 (inline_limit < extent_end)) {
564 u32 new_size;
565 new_size = btrfs_file_extent_calc_inline_size(
566 inline_limit - key.offset);
567 inode_sub_bytes(inode, extent_end -
568 inline_limit);
569 btrfs_set_file_extent_ram_bytes(leaf, extent,
570 new_size);
571 if (!compression && !encryption) {
572 btrfs_truncate_item(trans, root, path,
573 new_size, 1);
574 }
575 }
576 }
577 /* delete the entire extent */
578 if (!keep) {
579 if (found_inline)
580 inode_sub_bytes(inode, extent_end -
581 key.offset);
582 ret = btrfs_del_item(trans, root, path);
583 /* TODO update progress marker and return */
584 BUG_ON(ret);
585 extent = NULL;
586 btrfs_release_path(root, path);
587 /* the extent will be freed later */
588 }
589 if (bookend && found_inline && start <= key.offset) {
590 u32 new_size;
591 new_size = btrfs_file_extent_calc_inline_size(
592 extent_end - end);
593 inode_sub_bytes(inode, end - key.offset);
594 btrfs_set_file_extent_ram_bytes(leaf, extent,
595 new_size);
596 if (!compression && !encryption)
597 ret = btrfs_truncate_item(trans, root, path,
598 new_size, 0);
599 BUG_ON(ret);
600 }
601 /* create bookend, splitting the extent in two */
602 if (bookend && found_extent) {
603 struct btrfs_key ins;
604 ins.objectid = inode->i_ino;
605 ins.offset = end;
606 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
607
608 btrfs_release_path(root, path);
609 path->leave_spinning = 1;
610 ret = btrfs_insert_empty_item(trans, root, path, &ins,
611 sizeof(*extent));
612 BUG_ON(ret);
613
614 leaf = path->nodes[0];
615 extent = btrfs_item_ptr(leaf, path->slots[0],
616 struct btrfs_file_extent_item);
617 write_extent_buffer(leaf, &old,
618 (unsigned long)extent, sizeof(old));
619
620 btrfs_set_file_extent_compression(leaf, extent,
621 compression);
622 btrfs_set_file_extent_encryption(leaf, extent,
623 encryption);
624 btrfs_set_file_extent_other_encoding(leaf, extent,
625 other_encoding);
626 btrfs_set_file_extent_offset(leaf, extent,
627 le64_to_cpu(old.offset) + end - key.offset);
628 WARN_ON(le64_to_cpu(old.num_bytes) <
629 (extent_end - end));
630 btrfs_set_file_extent_num_bytes(leaf, extent,
631 extent_end - end);
632
633 /*
634 * set the ram bytes to the size of the full extent
635 * before splitting. This is a worst case flag,
636 * but its the best we can do because we don't know
637 * how splitting affects compression
638 */
639 btrfs_set_file_extent_ram_bytes(leaf, extent,
640 ram_bytes);
641 btrfs_set_file_extent_type(leaf, extent, found_type);
642
643 btrfs_unlock_up_safe(path, 1);
644 btrfs_mark_buffer_dirty(path->nodes[0]);
645 btrfs_set_lock_blocking(path->nodes[0]);
646
647 if (disk_bytenr != 0) {
648 ret = btrfs_update_extent_ref(trans, root,
649 disk_bytenr,
650 le64_to_cpu(old.disk_num_bytes),
651 orig_parent,
652 leaf->start,
653 root->root_key.objectid,
654 trans->transid, ins.objectid);
655
656 BUG_ON(ret);
657 }
658 path->leave_spinning = 0;
659 btrfs_release_path(root, path);
660 if (disk_bytenr != 0)
661 inode_add_bytes(inode, extent_end - end);
662 }
663
664 if (found_extent && !keep) {
665 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
666
667 if (old_disk_bytenr != 0) {
668 inode_sub_bytes(inode,
669 le64_to_cpu(old.num_bytes));
670 ret = btrfs_free_extent(trans, root,
671 old_disk_bytenr,
672 le64_to_cpu(old.disk_num_bytes),
673 leaf_start, root_owner,
674 root_gen, key.objectid, 0);
675 BUG_ON(ret);
676 *hint_byte = old_disk_bytenr;
677 }
678 }
679
680 if (search_start >= end) {
681 ret = 0;
682 goto out;
683 }
684 }
685 out:
686 btrfs_free_path(path);
687 if (locked_end > end) {
688 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
689 GFP_NOFS);
690 }
691 btrfs_check_file(root, inode);
692 return ret;
693 }
694
695 static int extent_mergeable(struct extent_buffer *leaf, int slot,
696 u64 objectid, u64 bytenr, u64 *start, u64 *end)
697 {
698 struct btrfs_file_extent_item *fi;
699 struct btrfs_key key;
700 u64 extent_end;
701
702 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
703 return 0;
704
705 btrfs_item_key_to_cpu(leaf, &key, slot);
706 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
707 return 0;
708
709 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
710 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
711 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
712 btrfs_file_extent_compression(leaf, fi) ||
713 btrfs_file_extent_encryption(leaf, fi) ||
714 btrfs_file_extent_other_encoding(leaf, fi))
715 return 0;
716
717 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
718 if ((*start && *start != key.offset) || (*end && *end != extent_end))
719 return 0;
720
721 *start = key.offset;
722 *end = extent_end;
723 return 1;
724 }
725
726 /*
727 * Mark extent in the range start - end as written.
728 *
729 * This changes extent type from 'pre-allocated' to 'regular'. If only
730 * part of extent is marked as written, the extent will be split into
731 * two or three.
732 */
733 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
734 struct btrfs_root *root,
735 struct inode *inode, u64 start, u64 end)
736 {
737 struct extent_buffer *leaf;
738 struct btrfs_path *path;
739 struct btrfs_file_extent_item *fi;
740 struct btrfs_key key;
741 u64 bytenr;
742 u64 num_bytes;
743 u64 extent_end;
744 u64 extent_offset;
745 u64 other_start;
746 u64 other_end;
747 u64 split = start;
748 u64 locked_end = end;
749 u64 orig_parent;
750 int extent_type;
751 int split_end = 1;
752 int ret;
753
754 btrfs_drop_extent_cache(inode, start, end - 1, 0);
755
756 path = btrfs_alloc_path();
757 BUG_ON(!path);
758 again:
759 key.objectid = inode->i_ino;
760 key.type = BTRFS_EXTENT_DATA_KEY;
761 if (split == start)
762 key.offset = split;
763 else
764 key.offset = split - 1;
765
766 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
767 if (ret > 0 && path->slots[0] > 0)
768 path->slots[0]--;
769
770 leaf = path->nodes[0];
771 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
772 BUG_ON(key.objectid != inode->i_ino ||
773 key.type != BTRFS_EXTENT_DATA_KEY);
774 fi = btrfs_item_ptr(leaf, path->slots[0],
775 struct btrfs_file_extent_item);
776 extent_type = btrfs_file_extent_type(leaf, fi);
777 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
778 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
779 BUG_ON(key.offset > start || extent_end < end);
780
781 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
782 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
783 extent_offset = btrfs_file_extent_offset(leaf, fi);
784
785 if (key.offset == start)
786 split = end;
787
788 if (key.offset == start && extent_end == end) {
789 int del_nr = 0;
790 int del_slot = 0;
791 u64 leaf_owner = btrfs_header_owner(leaf);
792 u64 leaf_gen = btrfs_header_generation(leaf);
793 other_start = end;
794 other_end = 0;
795 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
796 bytenr, &other_start, &other_end)) {
797 extent_end = other_end;
798 del_slot = path->slots[0] + 1;
799 del_nr++;
800 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
801 leaf->start, leaf_owner,
802 leaf_gen, inode->i_ino, 0);
803 BUG_ON(ret);
804 }
805 other_start = 0;
806 other_end = start;
807 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
808 bytenr, &other_start, &other_end)) {
809 key.offset = other_start;
810 del_slot = path->slots[0];
811 del_nr++;
812 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
813 leaf->start, leaf_owner,
814 leaf_gen, inode->i_ino, 0);
815 BUG_ON(ret);
816 }
817 split_end = 0;
818 if (del_nr == 0) {
819 btrfs_set_file_extent_type(leaf, fi,
820 BTRFS_FILE_EXTENT_REG);
821 goto done;
822 }
823
824 fi = btrfs_item_ptr(leaf, del_slot - 1,
825 struct btrfs_file_extent_item);
826 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
827 btrfs_set_file_extent_num_bytes(leaf, fi,
828 extent_end - key.offset);
829 btrfs_mark_buffer_dirty(leaf);
830
831 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
832 BUG_ON(ret);
833 goto done;
834 } else if (split == start) {
835 if (locked_end < extent_end) {
836 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
837 locked_end, extent_end - 1, GFP_NOFS);
838 if (!ret) {
839 btrfs_release_path(root, path);
840 lock_extent(&BTRFS_I(inode)->io_tree,
841 locked_end, extent_end - 1, GFP_NOFS);
842 locked_end = extent_end;
843 goto again;
844 }
845 locked_end = extent_end;
846 }
847 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
848 extent_offset += split - key.offset;
849 } else {
850 BUG_ON(key.offset != start);
851 btrfs_set_file_extent_offset(leaf, fi, extent_offset +
852 split - key.offset);
853 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
854 key.offset = split;
855 btrfs_set_item_key_safe(trans, root, path, &key);
856 extent_end = split;
857 }
858
859 if (extent_end == end) {
860 split_end = 0;
861 extent_type = BTRFS_FILE_EXTENT_REG;
862 }
863 if (extent_end == end && split == start) {
864 other_start = end;
865 other_end = 0;
866 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
867 bytenr, &other_start, &other_end)) {
868 path->slots[0]++;
869 fi = btrfs_item_ptr(leaf, path->slots[0],
870 struct btrfs_file_extent_item);
871 key.offset = split;
872 btrfs_set_item_key_safe(trans, root, path, &key);
873 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
874 btrfs_set_file_extent_num_bytes(leaf, fi,
875 other_end - split);
876 goto done;
877 }
878 }
879 if (extent_end == end && split == end) {
880 other_start = 0;
881 other_end = start;
882 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
883 bytenr, &other_start, &other_end)) {
884 path->slots[0]--;
885 fi = btrfs_item_ptr(leaf, path->slots[0],
886 struct btrfs_file_extent_item);
887 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
888 other_start);
889 goto done;
890 }
891 }
892
893 btrfs_mark_buffer_dirty(leaf);
894
895 orig_parent = leaf->start;
896 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
897 orig_parent, root->root_key.objectid,
898 trans->transid, inode->i_ino);
899 BUG_ON(ret);
900 btrfs_release_path(root, path);
901
902 key.offset = start;
903 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
904 BUG_ON(ret);
905
906 leaf = path->nodes[0];
907 fi = btrfs_item_ptr(leaf, path->slots[0],
908 struct btrfs_file_extent_item);
909 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
910 btrfs_set_file_extent_type(leaf, fi, extent_type);
911 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
912 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
913 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
914 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
915 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
916 btrfs_set_file_extent_compression(leaf, fi, 0);
917 btrfs_set_file_extent_encryption(leaf, fi, 0);
918 btrfs_set_file_extent_other_encoding(leaf, fi, 0);
919
920 if (orig_parent != leaf->start) {
921 ret = btrfs_update_extent_ref(trans, root, bytenr, num_bytes,
922 orig_parent, leaf->start,
923 root->root_key.objectid,
924 trans->transid, inode->i_ino);
925 BUG_ON(ret);
926 }
927 done:
928 btrfs_mark_buffer_dirty(leaf);
929 btrfs_release_path(root, path);
930 if (split_end && split == start) {
931 split = end;
932 goto again;
933 }
934 if (locked_end > end) {
935 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
936 GFP_NOFS);
937 }
938 btrfs_free_path(path);
939 return 0;
940 }
941
942 /*
943 * this gets pages into the page cache and locks them down, it also properly
944 * waits for data=ordered extents to finish before allowing the pages to be
945 * modified.
946 */
947 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
948 struct page **pages, size_t num_pages,
949 loff_t pos, unsigned long first_index,
950 unsigned long last_index, size_t write_bytes)
951 {
952 int i;
953 unsigned long index = pos >> PAGE_CACHE_SHIFT;
954 struct inode *inode = fdentry(file)->d_inode;
955 int err = 0;
956 u64 start_pos;
957 u64 last_pos;
958
959 start_pos = pos & ~((u64)root->sectorsize - 1);
960 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
961
962 if (start_pos > inode->i_size) {
963 err = btrfs_cont_expand(inode, start_pos);
964 if (err)
965 return err;
966 }
967
968 memset(pages, 0, num_pages * sizeof(struct page *));
969 again:
970 for (i = 0; i < num_pages; i++) {
971 pages[i] = grab_cache_page(inode->i_mapping, index + i);
972 if (!pages[i]) {
973 err = -ENOMEM;
974 BUG_ON(1);
975 }
976 wait_on_page_writeback(pages[i]);
977 }
978 if (start_pos < inode->i_size) {
979 struct btrfs_ordered_extent *ordered;
980 lock_extent(&BTRFS_I(inode)->io_tree,
981 start_pos, last_pos - 1, GFP_NOFS);
982 ordered = btrfs_lookup_first_ordered_extent(inode,
983 last_pos - 1);
984 if (ordered &&
985 ordered->file_offset + ordered->len > start_pos &&
986 ordered->file_offset < last_pos) {
987 btrfs_put_ordered_extent(ordered);
988 unlock_extent(&BTRFS_I(inode)->io_tree,
989 start_pos, last_pos - 1, GFP_NOFS);
990 for (i = 0; i < num_pages; i++) {
991 unlock_page(pages[i]);
992 page_cache_release(pages[i]);
993 }
994 btrfs_wait_ordered_range(inode, start_pos,
995 last_pos - start_pos);
996 goto again;
997 }
998 if (ordered)
999 btrfs_put_ordered_extent(ordered);
1000
1001 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
1002 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
1003 GFP_NOFS);
1004 unlock_extent(&BTRFS_I(inode)->io_tree,
1005 start_pos, last_pos - 1, GFP_NOFS);
1006 }
1007 for (i = 0; i < num_pages; i++) {
1008 clear_page_dirty_for_io(pages[i]);
1009 set_page_extent_mapped(pages[i]);
1010 WARN_ON(!PageLocked(pages[i]));
1011 }
1012 return 0;
1013 }
1014
1015 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
1016 size_t count, loff_t *ppos)
1017 {
1018 loff_t pos;
1019 loff_t start_pos;
1020 ssize_t num_written = 0;
1021 ssize_t err = 0;
1022 int ret = 0;
1023 struct inode *inode = fdentry(file)->d_inode;
1024 struct btrfs_root *root = BTRFS_I(inode)->root;
1025 struct page **pages = NULL;
1026 int nrptrs;
1027 struct page *pinned[2];
1028 unsigned long first_index;
1029 unsigned long last_index;
1030 int will_write;
1031
1032 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
1033 (file->f_flags & O_DIRECT));
1034
1035 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
1036 PAGE_CACHE_SIZE / (sizeof(struct page *)));
1037 pinned[0] = NULL;
1038 pinned[1] = NULL;
1039
1040 pos = *ppos;
1041 start_pos = pos;
1042
1043 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1044 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1045 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1046 if (err)
1047 goto out_nolock;
1048 if (count == 0)
1049 goto out_nolock;
1050
1051 err = file_remove_suid(file);
1052 if (err)
1053 goto out_nolock;
1054 file_update_time(file);
1055
1056 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1057
1058 mutex_lock(&inode->i_mutex);
1059 BTRFS_I(inode)->sequence++;
1060 first_index = pos >> PAGE_CACHE_SHIFT;
1061 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
1062
1063 /*
1064 * there are lots of better ways to do this, but this code
1065 * makes sure the first and last page in the file range are
1066 * up to date and ready for cow
1067 */
1068 if ((pos & (PAGE_CACHE_SIZE - 1))) {
1069 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
1070 if (!PageUptodate(pinned[0])) {
1071 ret = btrfs_readpage(NULL, pinned[0]);
1072 BUG_ON(ret);
1073 wait_on_page_locked(pinned[0]);
1074 } else {
1075 unlock_page(pinned[0]);
1076 }
1077 }
1078 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
1079 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
1080 if (!PageUptodate(pinned[1])) {
1081 ret = btrfs_readpage(NULL, pinned[1]);
1082 BUG_ON(ret);
1083 wait_on_page_locked(pinned[1]);
1084 } else {
1085 unlock_page(pinned[1]);
1086 }
1087 }
1088
1089 while (count > 0) {
1090 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1091 size_t write_bytes = min(count, nrptrs *
1092 (size_t)PAGE_CACHE_SIZE -
1093 offset);
1094 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
1095 PAGE_CACHE_SHIFT;
1096
1097 WARN_ON(num_pages > nrptrs);
1098 memset(pages, 0, sizeof(struct page *) * nrptrs);
1099
1100 ret = btrfs_check_data_free_space(root, inode, write_bytes);
1101 if (ret)
1102 goto out;
1103
1104 ret = prepare_pages(root, file, pages, num_pages,
1105 pos, first_index, last_index,
1106 write_bytes);
1107 if (ret) {
1108 btrfs_free_reserved_data_space(root, inode,
1109 write_bytes);
1110 goto out;
1111 }
1112
1113 ret = btrfs_copy_from_user(pos, num_pages,
1114 write_bytes, pages, buf);
1115 if (ret) {
1116 btrfs_free_reserved_data_space(root, inode,
1117 write_bytes);
1118 btrfs_drop_pages(pages, num_pages);
1119 goto out;
1120 }
1121
1122 ret = dirty_and_release_pages(NULL, root, file, pages,
1123 num_pages, pos, write_bytes);
1124 btrfs_drop_pages(pages, num_pages);
1125 if (ret) {
1126 btrfs_free_reserved_data_space(root, inode,
1127 write_bytes);
1128 goto out;
1129 }
1130
1131 if (will_write) {
1132 btrfs_fdatawrite_range(inode->i_mapping, pos,
1133 pos + write_bytes - 1,
1134 WB_SYNC_ALL);
1135 } else {
1136 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1137 num_pages);
1138 if (num_pages <
1139 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1140 btrfs_btree_balance_dirty(root, 1);
1141 btrfs_throttle(root);
1142 }
1143
1144 buf += write_bytes;
1145 count -= write_bytes;
1146 pos += write_bytes;
1147 num_written += write_bytes;
1148
1149 cond_resched();
1150 }
1151 out:
1152 mutex_unlock(&inode->i_mutex);
1153 if (ret)
1154 err = ret;
1155
1156 out_nolock:
1157 kfree(pages);
1158 if (pinned[0])
1159 page_cache_release(pinned[0]);
1160 if (pinned[1])
1161 page_cache_release(pinned[1]);
1162 *ppos = pos;
1163
1164 /*
1165 * we want to make sure fsync finds this change
1166 * but we haven't joined a transaction running right now.
1167 *
1168 * Later on, someone is sure to update the inode and get the
1169 * real transid recorded.
1170 *
1171 * We set last_trans now to the fs_info generation + 1,
1172 * this will either be one more than the running transaction
1173 * or the generation used for the next transaction if there isn't
1174 * one running right now.
1175 */
1176 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1177
1178 if (num_written > 0 && will_write) {
1179 struct btrfs_trans_handle *trans;
1180
1181 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1182 if (err)
1183 num_written = err;
1184
1185 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1186 trans = btrfs_start_transaction(root, 1);
1187 ret = btrfs_log_dentry_safe(trans, root,
1188 file->f_dentry);
1189 if (ret == 0) {
1190 ret = btrfs_sync_log(trans, root);
1191 if (ret == 0)
1192 btrfs_end_transaction(trans, root);
1193 else
1194 btrfs_commit_transaction(trans, root);
1195 } else {
1196 btrfs_commit_transaction(trans, root);
1197 }
1198 }
1199 if (file->f_flags & O_DIRECT) {
1200 invalidate_mapping_pages(inode->i_mapping,
1201 start_pos >> PAGE_CACHE_SHIFT,
1202 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1203 }
1204 }
1205 current->backing_dev_info = NULL;
1206 return num_written ? num_written : err;
1207 }
1208
1209 int btrfs_release_file(struct inode *inode, struct file *filp)
1210 {
1211 /*
1212 * ordered_data_close is set by settattr when we are about to truncate
1213 * a file from a non-zero size to a zero size. This tries to
1214 * flush down new bytes that may have been written if the
1215 * application were using truncate to replace a file in place.
1216 */
1217 if (BTRFS_I(inode)->ordered_data_close) {
1218 BTRFS_I(inode)->ordered_data_close = 0;
1219 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1220 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1221 filemap_flush(inode->i_mapping);
1222 }
1223 if (filp->private_data)
1224 btrfs_ioctl_trans_end(filp);
1225 return 0;
1226 }
1227
1228 /*
1229 * fsync call for both files and directories. This logs the inode into
1230 * the tree log instead of forcing full commits whenever possible.
1231 *
1232 * It needs to call filemap_fdatawait so that all ordered extent updates are
1233 * in the metadata btree are up to date for copying to the log.
1234 *
1235 * It drops the inode mutex before doing the tree log commit. This is an
1236 * important optimization for directories because holding the mutex prevents
1237 * new operations on the dir while we write to disk.
1238 */
1239 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1240 {
1241 struct inode *inode = dentry->d_inode;
1242 struct btrfs_root *root = BTRFS_I(inode)->root;
1243 int ret = 0;
1244 struct btrfs_trans_handle *trans;
1245
1246 /*
1247 * check the transaction that last modified this inode
1248 * and see if its already been committed
1249 */
1250 if (!BTRFS_I(inode)->last_trans)
1251 goto out;
1252
1253 mutex_lock(&root->fs_info->trans_mutex);
1254 if (BTRFS_I(inode)->last_trans <=
1255 root->fs_info->last_trans_committed) {
1256 BTRFS_I(inode)->last_trans = 0;
1257 mutex_unlock(&root->fs_info->trans_mutex);
1258 goto out;
1259 }
1260 mutex_unlock(&root->fs_info->trans_mutex);
1261
1262 root->log_batch++;
1263 filemap_fdatawrite(inode->i_mapping);
1264 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1265 root->log_batch++;
1266
1267 /*
1268 * ok we haven't committed the transaction yet, lets do a commit
1269 */
1270 if (file && file->private_data)
1271 btrfs_ioctl_trans_end(file);
1272
1273 trans = btrfs_start_transaction(root, 1);
1274 if (!trans) {
1275 ret = -ENOMEM;
1276 goto out;
1277 }
1278
1279 ret = btrfs_log_dentry_safe(trans, root, dentry);
1280 if (ret < 0)
1281 goto out;
1282
1283 /* we've logged all the items and now have a consistent
1284 * version of the file in the log. It is possible that
1285 * someone will come in and modify the file, but that's
1286 * fine because the log is consistent on disk, and we
1287 * have references to all of the file's extents
1288 *
1289 * It is possible that someone will come in and log the
1290 * file again, but that will end up using the synchronization
1291 * inside btrfs_sync_log to keep things safe.
1292 */
1293 mutex_unlock(&dentry->d_inode->i_mutex);
1294
1295 if (ret > 0) {
1296 ret = btrfs_commit_transaction(trans, root);
1297 } else {
1298 ret = btrfs_sync_log(trans, root);
1299 if (ret == 0)
1300 ret = btrfs_end_transaction(trans, root);
1301 else
1302 ret = btrfs_commit_transaction(trans, root);
1303 }
1304 mutex_lock(&dentry->d_inode->i_mutex);
1305 out:
1306 return ret > 0 ? EIO : ret;
1307 }
1308
1309 static struct vm_operations_struct btrfs_file_vm_ops = {
1310 .fault = filemap_fault,
1311 .page_mkwrite = btrfs_page_mkwrite,
1312 };
1313
1314 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1315 {
1316 vma->vm_ops = &btrfs_file_vm_ops;
1317 file_accessed(filp);
1318 return 0;
1319 }
1320
1321 struct file_operations btrfs_file_operations = {
1322 .llseek = generic_file_llseek,
1323 .read = do_sync_read,
1324 .aio_read = generic_file_aio_read,
1325 .splice_read = generic_file_splice_read,
1326 .write = btrfs_file_write,
1327 .mmap = btrfs_file_mmap,
1328 .open = generic_file_open,
1329 .release = btrfs_release_file,
1330 .fsync = btrfs_sync_file,
1331 .unlocked_ioctl = btrfs_ioctl,
1332 #ifdef CONFIG_COMPAT
1333 .compat_ioctl = btrfs_ioctl,
1334 #endif
1335 };
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