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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <linux/fs.h>
7#include <linux/pagemap.h>
8#include <linux/time.h>
9#include <linux/init.h>
10#include <linux/string.h>
11#include <linux/backing-dev.h>
12#include <linux/falloc.h>
13#include <linux/writeback.h>
14#include <linux/compat.h>
15#include <linux/slab.h>
16#include <linux/btrfs.h>
17#include <linux/uio.h>
18#include <linux/iversion.h>
19#include <linux/fsverity.h>
20#include "ctree.h"
21#include "disk-io.h"
22#include "transaction.h"
23#include "btrfs_inode.h"
24#include "print-tree.h"
25#include "tree-log.h"
26#include "locking.h"
27#include "volumes.h"
28#include "qgroup.h"
29#include "compression.h"
30#include "delalloc-space.h"
31#include "reflink.h"
32#include "subpage.h"
33#include "fs.h"
34#include "accessors.h"
35#include "extent-tree.h"
36#include "file-item.h"
37#include "ioctl.h"
38#include "file.h"
39#include "super.h"
40
41/* simple helper to fault in pages and copy. This should go away
42 * and be replaced with calls into generic code.
43 */
44static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
45 struct page **prepared_pages,
46 struct iov_iter *i)
47{
48 size_t copied = 0;
49 size_t total_copied = 0;
50 int pg = 0;
51 int offset = offset_in_page(pos);
52
53 while (write_bytes > 0) {
54 size_t count = min_t(size_t,
55 PAGE_SIZE - offset, write_bytes);
56 struct page *page = prepared_pages[pg];
57 /*
58 * Copy data from userspace to the current page
59 */
60 copied = copy_page_from_iter_atomic(page, offset, count, i);
61
62 /* Flush processor's dcache for this page */
63 flush_dcache_page(page);
64
65 /*
66 * if we get a partial write, we can end up with
67 * partially up to date pages. These add
68 * a lot of complexity, so make sure they don't
69 * happen by forcing this copy to be retried.
70 *
71 * The rest of the btrfs_file_write code will fall
72 * back to page at a time copies after we return 0.
73 */
74 if (unlikely(copied < count)) {
75 if (!PageUptodate(page)) {
76 iov_iter_revert(i, copied);
77 copied = 0;
78 }
79 if (!copied)
80 break;
81 }
82
83 write_bytes -= copied;
84 total_copied += copied;
85 offset += copied;
86 if (offset == PAGE_SIZE) {
87 pg++;
88 offset = 0;
89 }
90 }
91 return total_copied;
92}
93
94/*
95 * unlocks pages after btrfs_file_write is done with them
96 */
97static void btrfs_drop_pages(struct btrfs_fs_info *fs_info,
98 struct page **pages, size_t num_pages,
99 u64 pos, u64 copied)
100{
101 size_t i;
102 u64 block_start = round_down(pos, fs_info->sectorsize);
103 u64 block_len = round_up(pos + copied, fs_info->sectorsize) - block_start;
104
105 ASSERT(block_len <= U32_MAX);
106 for (i = 0; i < num_pages; i++) {
107 /* page checked is some magic around finding pages that
108 * have been modified without going through btrfs_set_page_dirty
109 * clear it here. There should be no need to mark the pages
110 * accessed as prepare_pages should have marked them accessed
111 * in prepare_pages via find_or_create_page()
112 */
113 btrfs_page_clamp_clear_checked(fs_info, pages[i], block_start,
114 block_len);
115 unlock_page(pages[i]);
116 put_page(pages[i]);
117 }
118}
119
120/*
121 * After btrfs_copy_from_user(), update the following things for delalloc:
122 * - Mark newly dirtied pages as DELALLOC in the io tree.
123 * Used to advise which range is to be written back.
124 * - Mark modified pages as Uptodate/Dirty and not needing COW fixup
125 * - Update inode size for past EOF write
126 */
127int btrfs_dirty_pages(struct btrfs_inode *inode, struct page **pages,
128 size_t num_pages, loff_t pos, size_t write_bytes,
129 struct extent_state **cached, bool noreserve)
130{
131 struct btrfs_fs_info *fs_info = inode->root->fs_info;
132 int err = 0;
133 int i;
134 u64 num_bytes;
135 u64 start_pos;
136 u64 end_of_last_block;
137 u64 end_pos = pos + write_bytes;
138 loff_t isize = i_size_read(&inode->vfs_inode);
139 unsigned int extra_bits = 0;
140
141 if (write_bytes == 0)
142 return 0;
143
144 if (noreserve)
145 extra_bits |= EXTENT_NORESERVE;
146
147 start_pos = round_down(pos, fs_info->sectorsize);
148 num_bytes = round_up(write_bytes + pos - start_pos,
149 fs_info->sectorsize);
150 ASSERT(num_bytes <= U32_MAX);
151
152 end_of_last_block = start_pos + num_bytes - 1;
153
154 /*
155 * The pages may have already been dirty, clear out old accounting so
156 * we can set things up properly
157 */
158 clear_extent_bit(&inode->io_tree, start_pos, end_of_last_block,
159 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
160 cached);
161
162 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
163 extra_bits, cached);
164 if (err)
165 return err;
166
167 for (i = 0; i < num_pages; i++) {
168 struct page *p = pages[i];
169
170 btrfs_page_clamp_set_uptodate(fs_info, p, start_pos, num_bytes);
171 btrfs_page_clamp_clear_checked(fs_info, p, start_pos, num_bytes);
172 btrfs_page_clamp_set_dirty(fs_info, p, start_pos, num_bytes);
173 }
174
175 /*
176 * we've only changed i_size in ram, and we haven't updated
177 * the disk i_size. There is no need to log the inode
178 * at this time.
179 */
180 if (end_pos > isize)
181 i_size_write(&inode->vfs_inode, end_pos);
182 return 0;
183}
184
185/*
186 * this is very complex, but the basic idea is to drop all extents
187 * in the range start - end. hint_block is filled in with a block number
188 * that would be a good hint to the block allocator for this file.
189 *
190 * If an extent intersects the range but is not entirely inside the range
191 * it is either truncated or split. Anything entirely inside the range
192 * is deleted from the tree.
193 *
194 * Note: the VFS' inode number of bytes is not updated, it's up to the caller
195 * to deal with that. We set the field 'bytes_found' of the arguments structure
196 * with the number of allocated bytes found in the target range, so that the
197 * caller can update the inode's number of bytes in an atomic way when
198 * replacing extents in a range to avoid races with stat(2).
199 */
200int btrfs_drop_extents(struct btrfs_trans_handle *trans,
201 struct btrfs_root *root, struct btrfs_inode *inode,
202 struct btrfs_drop_extents_args *args)
203{
204 struct btrfs_fs_info *fs_info = root->fs_info;
205 struct extent_buffer *leaf;
206 struct btrfs_file_extent_item *fi;
207 struct btrfs_ref ref = { 0 };
208 struct btrfs_key key;
209 struct btrfs_key new_key;
210 u64 ino = btrfs_ino(inode);
211 u64 search_start = args->start;
212 u64 disk_bytenr = 0;
213 u64 num_bytes = 0;
214 u64 extent_offset = 0;
215 u64 extent_end = 0;
216 u64 last_end = args->start;
217 int del_nr = 0;
218 int del_slot = 0;
219 int extent_type;
220 int recow;
221 int ret;
222 int modify_tree = -1;
223 int update_refs;
224 int found = 0;
225 struct btrfs_path *path = args->path;
226
227 args->bytes_found = 0;
228 args->extent_inserted = false;
229
230 /* Must always have a path if ->replace_extent is true */
231 ASSERT(!(args->replace_extent && !args->path));
232
233 if (!path) {
234 path = btrfs_alloc_path();
235 if (!path) {
236 ret = -ENOMEM;
237 goto out;
238 }
239 }
240
241 if (args->drop_cache)
242 btrfs_drop_extent_map_range(inode, args->start, args->end - 1, false);
243
244 if (args->start >= inode->disk_i_size && !args->replace_extent)
245 modify_tree = 0;
246
247 update_refs = (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID);
248 while (1) {
249 recow = 0;
250 ret = btrfs_lookup_file_extent(trans, root, path, ino,
251 search_start, modify_tree);
252 if (ret < 0)
253 break;
254 if (ret > 0 && path->slots[0] > 0 && search_start == args->start) {
255 leaf = path->nodes[0];
256 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
257 if (key.objectid == ino &&
258 key.type == BTRFS_EXTENT_DATA_KEY)
259 path->slots[0]--;
260 }
261 ret = 0;
262next_slot:
263 leaf = path->nodes[0];
264 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
265 BUG_ON(del_nr > 0);
266 ret = btrfs_next_leaf(root, path);
267 if (ret < 0)
268 break;
269 if (ret > 0) {
270 ret = 0;
271 break;
272 }
273 leaf = path->nodes[0];
274 recow = 1;
275 }
276
277 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
278
279 if (key.objectid > ino)
280 break;
281 if (WARN_ON_ONCE(key.objectid < ino) ||
282 key.type < BTRFS_EXTENT_DATA_KEY) {
283 ASSERT(del_nr == 0);
284 path->slots[0]++;
285 goto next_slot;
286 }
287 if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= args->end)
288 break;
289
290 fi = btrfs_item_ptr(leaf, path->slots[0],
291 struct btrfs_file_extent_item);
292 extent_type = btrfs_file_extent_type(leaf, fi);
293
294 if (extent_type == BTRFS_FILE_EXTENT_REG ||
295 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
296 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
297 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
298 extent_offset = btrfs_file_extent_offset(leaf, fi);
299 extent_end = key.offset +
300 btrfs_file_extent_num_bytes(leaf, fi);
301 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
302 extent_end = key.offset +
303 btrfs_file_extent_ram_bytes(leaf, fi);
304 } else {
305 /* can't happen */
306 BUG();
307 }
308
309 /*
310 * Don't skip extent items representing 0 byte lengths. They
311 * used to be created (bug) if while punching holes we hit
312 * -ENOSPC condition. So if we find one here, just ensure we
313 * delete it, otherwise we would insert a new file extent item
314 * with the same key (offset) as that 0 bytes length file
315 * extent item in the call to setup_items_for_insert() later
316 * in this function.
317 */
318 if (extent_end == key.offset && extent_end >= search_start) {
319 last_end = extent_end;
320 goto delete_extent_item;
321 }
322
323 if (extent_end <= search_start) {
324 path->slots[0]++;
325 goto next_slot;
326 }
327
328 found = 1;
329 search_start = max(key.offset, args->start);
330 if (recow || !modify_tree) {
331 modify_tree = -1;
332 btrfs_release_path(path);
333 continue;
334 }
335
336 /*
337 * | - range to drop - |
338 * | -------- extent -------- |
339 */
340 if (args->start > key.offset && args->end < extent_end) {
341 BUG_ON(del_nr > 0);
342 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
343 ret = -EOPNOTSUPP;
344 break;
345 }
346
347 memcpy(&new_key, &key, sizeof(new_key));
348 new_key.offset = args->start;
349 ret = btrfs_duplicate_item(trans, root, path,
350 &new_key);
351 if (ret == -EAGAIN) {
352 btrfs_release_path(path);
353 continue;
354 }
355 if (ret < 0)
356 break;
357
358 leaf = path->nodes[0];
359 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
360 struct btrfs_file_extent_item);
361 btrfs_set_file_extent_num_bytes(leaf, fi,
362 args->start - key.offset);
363
364 fi = btrfs_item_ptr(leaf, path->slots[0],
365 struct btrfs_file_extent_item);
366
367 extent_offset += args->start - key.offset;
368 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
369 btrfs_set_file_extent_num_bytes(leaf, fi,
370 extent_end - args->start);
371 btrfs_mark_buffer_dirty(leaf);
372
373 if (update_refs && disk_bytenr > 0) {
374 btrfs_init_generic_ref(&ref,
375 BTRFS_ADD_DELAYED_REF,
376 disk_bytenr, num_bytes, 0);
377 btrfs_init_data_ref(&ref,
378 root->root_key.objectid,
379 new_key.objectid,
380 args->start - extent_offset,
381 0, false);
382 ret = btrfs_inc_extent_ref(trans, &ref);
383 if (ret) {
384 btrfs_abort_transaction(trans, ret);
385 break;
386 }
387 }
388 key.offset = args->start;
389 }
390 /*
391 * From here on out we will have actually dropped something, so
392 * last_end can be updated.
393 */
394 last_end = extent_end;
395
396 /*
397 * | ---- range to drop ----- |
398 * | -------- extent -------- |
399 */
400 if (args->start <= key.offset && args->end < extent_end) {
401 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
402 ret = -EOPNOTSUPP;
403 break;
404 }
405
406 memcpy(&new_key, &key, sizeof(new_key));
407 new_key.offset = args->end;
408 btrfs_set_item_key_safe(fs_info, path, &new_key);
409
410 extent_offset += args->end - key.offset;
411 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
412 btrfs_set_file_extent_num_bytes(leaf, fi,
413 extent_end - args->end);
414 btrfs_mark_buffer_dirty(leaf);
415 if (update_refs && disk_bytenr > 0)
416 args->bytes_found += args->end - key.offset;
417 break;
418 }
419
420 search_start = extent_end;
421 /*
422 * | ---- range to drop ----- |
423 * | -------- extent -------- |
424 */
425 if (args->start > key.offset && args->end >= extent_end) {
426 BUG_ON(del_nr > 0);
427 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
428 ret = -EOPNOTSUPP;
429 break;
430 }
431
432 btrfs_set_file_extent_num_bytes(leaf, fi,
433 args->start - key.offset);
434 btrfs_mark_buffer_dirty(leaf);
435 if (update_refs && disk_bytenr > 0)
436 args->bytes_found += extent_end - args->start;
437 if (args->end == extent_end)
438 break;
439
440 path->slots[0]++;
441 goto next_slot;
442 }
443
444 /*
445 * | ---- range to drop ----- |
446 * | ------ extent ------ |
447 */
448 if (args->start <= key.offset && args->end >= extent_end) {
449delete_extent_item:
450 if (del_nr == 0) {
451 del_slot = path->slots[0];
452 del_nr = 1;
453 } else {
454 BUG_ON(del_slot + del_nr != path->slots[0]);
455 del_nr++;
456 }
457
458 if (update_refs &&
459 extent_type == BTRFS_FILE_EXTENT_INLINE) {
460 args->bytes_found += extent_end - key.offset;
461 extent_end = ALIGN(extent_end,
462 fs_info->sectorsize);
463 } else if (update_refs && disk_bytenr > 0) {
464 btrfs_init_generic_ref(&ref,
465 BTRFS_DROP_DELAYED_REF,
466 disk_bytenr, num_bytes, 0);
467 btrfs_init_data_ref(&ref,
468 root->root_key.objectid,
469 key.objectid,
470 key.offset - extent_offset, 0,
471 false);
472 ret = btrfs_free_extent(trans, &ref);
473 if (ret) {
474 btrfs_abort_transaction(trans, ret);
475 break;
476 }
477 args->bytes_found += extent_end - key.offset;
478 }
479
480 if (args->end == extent_end)
481 break;
482
483 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
484 path->slots[0]++;
485 goto next_slot;
486 }
487
488 ret = btrfs_del_items(trans, root, path, del_slot,
489 del_nr);
490 if (ret) {
491 btrfs_abort_transaction(trans, ret);
492 break;
493 }
494
495 del_nr = 0;
496 del_slot = 0;
497
498 btrfs_release_path(path);
499 continue;
500 }
501
502 BUG();
503 }
504
505 if (!ret && del_nr > 0) {
506 /*
507 * Set path->slots[0] to first slot, so that after the delete
508 * if items are move off from our leaf to its immediate left or
509 * right neighbor leafs, we end up with a correct and adjusted
510 * path->slots[0] for our insertion (if args->replace_extent).
511 */
512 path->slots[0] = del_slot;
513 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
514 if (ret)
515 btrfs_abort_transaction(trans, ret);
516 }
517
518 leaf = path->nodes[0];
519 /*
520 * If btrfs_del_items() was called, it might have deleted a leaf, in
521 * which case it unlocked our path, so check path->locks[0] matches a
522 * write lock.
523 */
524 if (!ret && args->replace_extent &&
525 path->locks[0] == BTRFS_WRITE_LOCK &&
526 btrfs_leaf_free_space(leaf) >=
527 sizeof(struct btrfs_item) + args->extent_item_size) {
528
529 key.objectid = ino;
530 key.type = BTRFS_EXTENT_DATA_KEY;
531 key.offset = args->start;
532 if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
533 struct btrfs_key slot_key;
534
535 btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
536 if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
537 path->slots[0]++;
538 }
539 btrfs_setup_item_for_insert(root, path, &key, args->extent_item_size);
540 args->extent_inserted = true;
541 }
542
543 if (!args->path)
544 btrfs_free_path(path);
545 else if (!args->extent_inserted)
546 btrfs_release_path(path);
547out:
548 args->drop_end = found ? min(args->end, last_end) : args->end;
549
550 return ret;
551}
552
553static int extent_mergeable(struct extent_buffer *leaf, int slot,
554 u64 objectid, u64 bytenr, u64 orig_offset,
555 u64 *start, u64 *end)
556{
557 struct btrfs_file_extent_item *fi;
558 struct btrfs_key key;
559 u64 extent_end;
560
561 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
562 return 0;
563
564 btrfs_item_key_to_cpu(leaf, &key, slot);
565 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
566 return 0;
567
568 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
569 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
570 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
571 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
572 btrfs_file_extent_compression(leaf, fi) ||
573 btrfs_file_extent_encryption(leaf, fi) ||
574 btrfs_file_extent_other_encoding(leaf, fi))
575 return 0;
576
577 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
578 if ((*start && *start != key.offset) || (*end && *end != extent_end))
579 return 0;
580
581 *start = key.offset;
582 *end = extent_end;
583 return 1;
584}
585
586/*
587 * Mark extent in the range start - end as written.
588 *
589 * This changes extent type from 'pre-allocated' to 'regular'. If only
590 * part of extent is marked as written, the extent will be split into
591 * two or three.
592 */
593int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
594 struct btrfs_inode *inode, u64 start, u64 end)
595{
596 struct btrfs_fs_info *fs_info = trans->fs_info;
597 struct btrfs_root *root = inode->root;
598 struct extent_buffer *leaf;
599 struct btrfs_path *path;
600 struct btrfs_file_extent_item *fi;
601 struct btrfs_ref ref = { 0 };
602 struct btrfs_key key;
603 struct btrfs_key new_key;
604 u64 bytenr;
605 u64 num_bytes;
606 u64 extent_end;
607 u64 orig_offset;
608 u64 other_start;
609 u64 other_end;
610 u64 split;
611 int del_nr = 0;
612 int del_slot = 0;
613 int recow;
614 int ret = 0;
615 u64 ino = btrfs_ino(inode);
616
617 path = btrfs_alloc_path();
618 if (!path)
619 return -ENOMEM;
620again:
621 recow = 0;
622 split = start;
623 key.objectid = ino;
624 key.type = BTRFS_EXTENT_DATA_KEY;
625 key.offset = split;
626
627 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
628 if (ret < 0)
629 goto out;
630 if (ret > 0 && path->slots[0] > 0)
631 path->slots[0]--;
632
633 leaf = path->nodes[0];
634 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
635 if (key.objectid != ino ||
636 key.type != BTRFS_EXTENT_DATA_KEY) {
637 ret = -EINVAL;
638 btrfs_abort_transaction(trans, ret);
639 goto out;
640 }
641 fi = btrfs_item_ptr(leaf, path->slots[0],
642 struct btrfs_file_extent_item);
643 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
644 ret = -EINVAL;
645 btrfs_abort_transaction(trans, ret);
646 goto out;
647 }
648 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
649 if (key.offset > start || extent_end < end) {
650 ret = -EINVAL;
651 btrfs_abort_transaction(trans, ret);
652 goto out;
653 }
654
655 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
656 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
657 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
658 memcpy(&new_key, &key, sizeof(new_key));
659
660 if (start == key.offset && end < extent_end) {
661 other_start = 0;
662 other_end = start;
663 if (extent_mergeable(leaf, path->slots[0] - 1,
664 ino, bytenr, orig_offset,
665 &other_start, &other_end)) {
666 new_key.offset = end;
667 btrfs_set_item_key_safe(fs_info, path, &new_key);
668 fi = btrfs_item_ptr(leaf, path->slots[0],
669 struct btrfs_file_extent_item);
670 btrfs_set_file_extent_generation(leaf, fi,
671 trans->transid);
672 btrfs_set_file_extent_num_bytes(leaf, fi,
673 extent_end - end);
674 btrfs_set_file_extent_offset(leaf, fi,
675 end - orig_offset);
676 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
677 struct btrfs_file_extent_item);
678 btrfs_set_file_extent_generation(leaf, fi,
679 trans->transid);
680 btrfs_set_file_extent_num_bytes(leaf, fi,
681 end - other_start);
682 btrfs_mark_buffer_dirty(leaf);
683 goto out;
684 }
685 }
686
687 if (start > key.offset && end == extent_end) {
688 other_start = end;
689 other_end = 0;
690 if (extent_mergeable(leaf, path->slots[0] + 1,
691 ino, bytenr, orig_offset,
692 &other_start, &other_end)) {
693 fi = btrfs_item_ptr(leaf, path->slots[0],
694 struct btrfs_file_extent_item);
695 btrfs_set_file_extent_num_bytes(leaf, fi,
696 start - key.offset);
697 btrfs_set_file_extent_generation(leaf, fi,
698 trans->transid);
699 path->slots[0]++;
700 new_key.offset = start;
701 btrfs_set_item_key_safe(fs_info, path, &new_key);
702
703 fi = btrfs_item_ptr(leaf, path->slots[0],
704 struct btrfs_file_extent_item);
705 btrfs_set_file_extent_generation(leaf, fi,
706 trans->transid);
707 btrfs_set_file_extent_num_bytes(leaf, fi,
708 other_end - start);
709 btrfs_set_file_extent_offset(leaf, fi,
710 start - orig_offset);
711 btrfs_mark_buffer_dirty(leaf);
712 goto out;
713 }
714 }
715
716 while (start > key.offset || end < extent_end) {
717 if (key.offset == start)
718 split = end;
719
720 new_key.offset = split;
721 ret = btrfs_duplicate_item(trans, root, path, &new_key);
722 if (ret == -EAGAIN) {
723 btrfs_release_path(path);
724 goto again;
725 }
726 if (ret < 0) {
727 btrfs_abort_transaction(trans, ret);
728 goto out;
729 }
730
731 leaf = path->nodes[0];
732 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
733 struct btrfs_file_extent_item);
734 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
735 btrfs_set_file_extent_num_bytes(leaf, fi,
736 split - key.offset);
737
738 fi = btrfs_item_ptr(leaf, path->slots[0],
739 struct btrfs_file_extent_item);
740
741 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
742 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
743 btrfs_set_file_extent_num_bytes(leaf, fi,
744 extent_end - split);
745 btrfs_mark_buffer_dirty(leaf);
746
747 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, bytenr,
748 num_bytes, 0);
749 btrfs_init_data_ref(&ref, root->root_key.objectid, ino,
750 orig_offset, 0, false);
751 ret = btrfs_inc_extent_ref(trans, &ref);
752 if (ret) {
753 btrfs_abort_transaction(trans, ret);
754 goto out;
755 }
756
757 if (split == start) {
758 key.offset = start;
759 } else {
760 if (start != key.offset) {
761 ret = -EINVAL;
762 btrfs_abort_transaction(trans, ret);
763 goto out;
764 }
765 path->slots[0]--;
766 extent_end = end;
767 }
768 recow = 1;
769 }
770
771 other_start = end;
772 other_end = 0;
773 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
774 num_bytes, 0);
775 btrfs_init_data_ref(&ref, root->root_key.objectid, ino, orig_offset,
776 0, false);
777 if (extent_mergeable(leaf, path->slots[0] + 1,
778 ino, bytenr, orig_offset,
779 &other_start, &other_end)) {
780 if (recow) {
781 btrfs_release_path(path);
782 goto again;
783 }
784 extent_end = other_end;
785 del_slot = path->slots[0] + 1;
786 del_nr++;
787 ret = btrfs_free_extent(trans, &ref);
788 if (ret) {
789 btrfs_abort_transaction(trans, ret);
790 goto out;
791 }
792 }
793 other_start = 0;
794 other_end = start;
795 if (extent_mergeable(leaf, path->slots[0] - 1,
796 ino, bytenr, orig_offset,
797 &other_start, &other_end)) {
798 if (recow) {
799 btrfs_release_path(path);
800 goto again;
801 }
802 key.offset = other_start;
803 del_slot = path->slots[0];
804 del_nr++;
805 ret = btrfs_free_extent(trans, &ref);
806 if (ret) {
807 btrfs_abort_transaction(trans, ret);
808 goto out;
809 }
810 }
811 if (del_nr == 0) {
812 fi = btrfs_item_ptr(leaf, path->slots[0],
813 struct btrfs_file_extent_item);
814 btrfs_set_file_extent_type(leaf, fi,
815 BTRFS_FILE_EXTENT_REG);
816 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
817 btrfs_mark_buffer_dirty(leaf);
818 } else {
819 fi = btrfs_item_ptr(leaf, del_slot - 1,
820 struct btrfs_file_extent_item);
821 btrfs_set_file_extent_type(leaf, fi,
822 BTRFS_FILE_EXTENT_REG);
823 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
824 btrfs_set_file_extent_num_bytes(leaf, fi,
825 extent_end - key.offset);
826 btrfs_mark_buffer_dirty(leaf);
827
828 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
829 if (ret < 0) {
830 btrfs_abort_transaction(trans, ret);
831 goto out;
832 }
833 }
834out:
835 btrfs_free_path(path);
836 return ret;
837}
838
839/*
840 * on error we return an unlocked page and the error value
841 * on success we return a locked page and 0
842 */
843static int prepare_uptodate_page(struct inode *inode,
844 struct page *page, u64 pos,
845 bool force_uptodate)
846{
847 struct folio *folio = page_folio(page);
848 int ret = 0;
849
850 if (((pos & (PAGE_SIZE - 1)) || force_uptodate) &&
851 !PageUptodate(page)) {
852 ret = btrfs_read_folio(NULL, folio);
853 if (ret)
854 return ret;
855 lock_page(page);
856 if (!PageUptodate(page)) {
857 unlock_page(page);
858 return -EIO;
859 }
860
861 /*
862 * Since btrfs_read_folio() will unlock the folio before it
863 * returns, there is a window where btrfs_release_folio() can be
864 * called to release the page. Here we check both inode
865 * mapping and PagePrivate() to make sure the page was not
866 * released.
867 *
868 * The private flag check is essential for subpage as we need
869 * to store extra bitmap using page->private.
870 */
871 if (page->mapping != inode->i_mapping || !PagePrivate(page)) {
872 unlock_page(page);
873 return -EAGAIN;
874 }
875 }
876 return 0;
877}
878
879static unsigned int get_prepare_fgp_flags(bool nowait)
880{
881 unsigned int fgp_flags = FGP_LOCK | FGP_ACCESSED | FGP_CREAT;
882
883 if (nowait)
884 fgp_flags |= FGP_NOWAIT;
885
886 return fgp_flags;
887}
888
889static gfp_t get_prepare_gfp_flags(struct inode *inode, bool nowait)
890{
891 gfp_t gfp;
892
893 gfp = btrfs_alloc_write_mask(inode->i_mapping);
894 if (nowait) {
895 gfp &= ~__GFP_DIRECT_RECLAIM;
896 gfp |= GFP_NOWAIT;
897 }
898
899 return gfp;
900}
901
902/*
903 * this just gets pages into the page cache and locks them down.
904 */
905static noinline int prepare_pages(struct inode *inode, struct page **pages,
906 size_t num_pages, loff_t pos,
907 size_t write_bytes, bool force_uptodate,
908 bool nowait)
909{
910 int i;
911 unsigned long index = pos >> PAGE_SHIFT;
912 gfp_t mask = get_prepare_gfp_flags(inode, nowait);
913 unsigned int fgp_flags = get_prepare_fgp_flags(nowait);
914 int err = 0;
915 int faili;
916
917 for (i = 0; i < num_pages; i++) {
918again:
919 pages[i] = pagecache_get_page(inode->i_mapping, index + i,
920 fgp_flags, mask | __GFP_WRITE);
921 if (!pages[i]) {
922 faili = i - 1;
923 if (nowait)
924 err = -EAGAIN;
925 else
926 err = -ENOMEM;
927 goto fail;
928 }
929
930 err = set_page_extent_mapped(pages[i]);
931 if (err < 0) {
932 faili = i;
933 goto fail;
934 }
935
936 if (i == 0)
937 err = prepare_uptodate_page(inode, pages[i], pos,
938 force_uptodate);
939 if (!err && i == num_pages - 1)
940 err = prepare_uptodate_page(inode, pages[i],
941 pos + write_bytes, false);
942 if (err) {
943 put_page(pages[i]);
944 if (!nowait && err == -EAGAIN) {
945 err = 0;
946 goto again;
947 }
948 faili = i - 1;
949 goto fail;
950 }
951 wait_on_page_writeback(pages[i]);
952 }
953
954 return 0;
955fail:
956 while (faili >= 0) {
957 unlock_page(pages[faili]);
958 put_page(pages[faili]);
959 faili--;
960 }
961 return err;
962
963}
964
965/*
966 * This function locks the extent and properly waits for data=ordered extents
967 * to finish before allowing the pages to be modified if need.
968 *
969 * The return value:
970 * 1 - the extent is locked
971 * 0 - the extent is not locked, and everything is OK
972 * -EAGAIN - need re-prepare the pages
973 * the other < 0 number - Something wrong happens
974 */
975static noinline int
976lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
977 size_t num_pages, loff_t pos,
978 size_t write_bytes,
979 u64 *lockstart, u64 *lockend, bool nowait,
980 struct extent_state **cached_state)
981{
982 struct btrfs_fs_info *fs_info = inode->root->fs_info;
983 u64 start_pos;
984 u64 last_pos;
985 int i;
986 int ret = 0;
987
988 start_pos = round_down(pos, fs_info->sectorsize);
989 last_pos = round_up(pos + write_bytes, fs_info->sectorsize) - 1;
990
991 if (start_pos < inode->vfs_inode.i_size) {
992 struct btrfs_ordered_extent *ordered;
993
994 if (nowait) {
995 if (!try_lock_extent(&inode->io_tree, start_pos, last_pos,
996 cached_state)) {
997 for (i = 0; i < num_pages; i++) {
998 unlock_page(pages[i]);
999 put_page(pages[i]);
1000 pages[i] = NULL;
1001 }
1002
1003 return -EAGAIN;
1004 }
1005 } else {
1006 lock_extent(&inode->io_tree, start_pos, last_pos, cached_state);
1007 }
1008
1009 ordered = btrfs_lookup_ordered_range(inode, start_pos,
1010 last_pos - start_pos + 1);
1011 if (ordered &&
1012 ordered->file_offset + ordered->num_bytes > start_pos &&
1013 ordered->file_offset <= last_pos) {
1014 unlock_extent(&inode->io_tree, start_pos, last_pos,
1015 cached_state);
1016 for (i = 0; i < num_pages; i++) {
1017 unlock_page(pages[i]);
1018 put_page(pages[i]);
1019 }
1020 btrfs_start_ordered_extent(ordered, 1);
1021 btrfs_put_ordered_extent(ordered);
1022 return -EAGAIN;
1023 }
1024 if (ordered)
1025 btrfs_put_ordered_extent(ordered);
1026
1027 *lockstart = start_pos;
1028 *lockend = last_pos;
1029 ret = 1;
1030 }
1031
1032 /*
1033 * We should be called after prepare_pages() which should have locked
1034 * all pages in the range.
1035 */
1036 for (i = 0; i < num_pages; i++)
1037 WARN_ON(!PageLocked(pages[i]));
1038
1039 return ret;
1040}
1041
1042/*
1043 * Check if we can do nocow write into the range [@pos, @pos + @write_bytes)
1044 *
1045 * @pos: File offset.
1046 * @write_bytes: The length to write, will be updated to the nocow writeable
1047 * range.
1048 *
1049 * This function will flush ordered extents in the range to ensure proper
1050 * nocow checks.
1051 *
1052 * Return:
1053 * > 0 If we can nocow, and updates @write_bytes.
1054 * 0 If we can't do a nocow write.
1055 * -EAGAIN If we can't do a nocow write because snapshoting of the inode's
1056 * root is in progress.
1057 * < 0 If an error happened.
1058 *
1059 * NOTE: Callers need to call btrfs_check_nocow_unlock() if we return > 0.
1060 */
1061int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
1062 size_t *write_bytes, bool nowait)
1063{
1064 struct btrfs_fs_info *fs_info = inode->root->fs_info;
1065 struct btrfs_root *root = inode->root;
1066 struct extent_state *cached_state = NULL;
1067 u64 lockstart, lockend;
1068 u64 num_bytes;
1069 int ret;
1070
1071 if (!(inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)))
1072 return 0;
1073
1074 if (!btrfs_drew_try_write_lock(&root->snapshot_lock))
1075 return -EAGAIN;
1076
1077 lockstart = round_down(pos, fs_info->sectorsize);
1078 lockend = round_up(pos + *write_bytes,
1079 fs_info->sectorsize) - 1;
1080 num_bytes = lockend - lockstart + 1;
1081
1082 if (nowait) {
1083 if (!btrfs_try_lock_ordered_range(inode, lockstart, lockend,
1084 &cached_state)) {
1085 btrfs_drew_write_unlock(&root->snapshot_lock);
1086 return -EAGAIN;
1087 }
1088 } else {
1089 btrfs_lock_and_flush_ordered_range(inode, lockstart, lockend,
1090 &cached_state);
1091 }
1092 ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
1093 NULL, NULL, NULL, nowait, false);
1094 if (ret <= 0)
1095 btrfs_drew_write_unlock(&root->snapshot_lock);
1096 else
1097 *write_bytes = min_t(size_t, *write_bytes ,
1098 num_bytes - pos + lockstart);
1099 unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
1100
1101 return ret;
1102}
1103
1104void btrfs_check_nocow_unlock(struct btrfs_inode *inode)
1105{
1106 btrfs_drew_write_unlock(&inode->root->snapshot_lock);
1107}
1108
1109static void update_time_for_write(struct inode *inode)
1110{
1111 struct timespec64 now;
1112
1113 if (IS_NOCMTIME(inode))
1114 return;
1115
1116 now = current_time(inode);
1117 if (!timespec64_equal(&inode->i_mtime, &now))
1118 inode->i_mtime = now;
1119
1120 if (!timespec64_equal(&inode->i_ctime, &now))
1121 inode->i_ctime = now;
1122
1123 if (IS_I_VERSION(inode))
1124 inode_inc_iversion(inode);
1125}
1126
1127static int btrfs_write_check(struct kiocb *iocb, struct iov_iter *from,
1128 size_t count)
1129{
1130 struct file *file = iocb->ki_filp;
1131 struct inode *inode = file_inode(file);
1132 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1133 loff_t pos = iocb->ki_pos;
1134 int ret;
1135 loff_t oldsize;
1136 loff_t start_pos;
1137
1138 /*
1139 * Quickly bail out on NOWAIT writes if we don't have the nodatacow or
1140 * prealloc flags, as without those flags we always have to COW. We will
1141 * later check if we can really COW into the target range (using
1142 * can_nocow_extent() at btrfs_get_blocks_direct_write()).
1143 */
1144 if ((iocb->ki_flags & IOCB_NOWAIT) &&
1145 !(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)))
1146 return -EAGAIN;
1147
1148 current->backing_dev_info = inode_to_bdi(inode);
1149 ret = file_remove_privs(file);
1150 if (ret)
1151 return ret;
1152
1153 /*
1154 * We reserve space for updating the inode when we reserve space for the
1155 * extent we are going to write, so we will enospc out there. We don't
1156 * need to start yet another transaction to update the inode as we will
1157 * update the inode when we finish writing whatever data we write.
1158 */
1159 update_time_for_write(inode);
1160
1161 start_pos = round_down(pos, fs_info->sectorsize);
1162 oldsize = i_size_read(inode);
1163 if (start_pos > oldsize) {
1164 /* Expand hole size to cover write data, preventing empty gap */
1165 loff_t end_pos = round_up(pos + count, fs_info->sectorsize);
1166
1167 ret = btrfs_cont_expand(BTRFS_I(inode), oldsize, end_pos);
1168 if (ret) {
1169 current->backing_dev_info = NULL;
1170 return ret;
1171 }
1172 }
1173
1174 return 0;
1175}
1176
1177static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
1178 struct iov_iter *i)
1179{
1180 struct file *file = iocb->ki_filp;
1181 loff_t pos;
1182 struct inode *inode = file_inode(file);
1183 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1184 struct page **pages = NULL;
1185 struct extent_changeset *data_reserved = NULL;
1186 u64 release_bytes = 0;
1187 u64 lockstart;
1188 u64 lockend;
1189 size_t num_written = 0;
1190 int nrptrs;
1191 ssize_t ret;
1192 bool only_release_metadata = false;
1193 bool force_page_uptodate = false;
1194 loff_t old_isize = i_size_read(inode);
1195 unsigned int ilock_flags = 0;
1196 const bool nowait = (iocb->ki_flags & IOCB_NOWAIT);
1197 unsigned int bdp_flags = (nowait ? BDP_ASYNC : 0);
1198
1199 if (nowait)
1200 ilock_flags |= BTRFS_ILOCK_TRY;
1201
1202 ret = btrfs_inode_lock(BTRFS_I(inode), ilock_flags);
1203 if (ret < 0)
1204 return ret;
1205
1206 ret = generic_write_checks(iocb, i);
1207 if (ret <= 0)
1208 goto out;
1209
1210 ret = btrfs_write_check(iocb, i, ret);
1211 if (ret < 0)
1212 goto out;
1213
1214 pos = iocb->ki_pos;
1215 nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
1216 PAGE_SIZE / (sizeof(struct page *)));
1217 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1218 nrptrs = max(nrptrs, 8);
1219 pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
1220 if (!pages) {
1221 ret = -ENOMEM;
1222 goto out;
1223 }
1224
1225 while (iov_iter_count(i) > 0) {
1226 struct extent_state *cached_state = NULL;
1227 size_t offset = offset_in_page(pos);
1228 size_t sector_offset;
1229 size_t write_bytes = min(iov_iter_count(i),
1230 nrptrs * (size_t)PAGE_SIZE -
1231 offset);
1232 size_t num_pages;
1233 size_t reserve_bytes;
1234 size_t dirty_pages;
1235 size_t copied;
1236 size_t dirty_sectors;
1237 size_t num_sectors;
1238 int extents_locked;
1239
1240 /*
1241 * Fault pages before locking them in prepare_pages
1242 * to avoid recursive lock
1243 */
1244 if (unlikely(fault_in_iov_iter_readable(i, write_bytes))) {
1245 ret = -EFAULT;
1246 break;
1247 }
1248
1249 only_release_metadata = false;
1250 sector_offset = pos & (fs_info->sectorsize - 1);
1251
1252 extent_changeset_release(data_reserved);
1253 ret = btrfs_check_data_free_space(BTRFS_I(inode),
1254 &data_reserved, pos,
1255 write_bytes, nowait);
1256 if (ret < 0) {
1257 int can_nocow;
1258
1259 if (nowait && (ret == -ENOSPC || ret == -EAGAIN)) {
1260 ret = -EAGAIN;
1261 break;
1262 }
1263
1264 /*
1265 * If we don't have to COW at the offset, reserve
1266 * metadata only. write_bytes may get smaller than
1267 * requested here.
1268 */
1269 can_nocow = btrfs_check_nocow_lock(BTRFS_I(inode), pos,
1270 &write_bytes, nowait);
1271 if (can_nocow < 0)
1272 ret = can_nocow;
1273 if (can_nocow > 0)
1274 ret = 0;
1275 if (ret)
1276 break;
1277 only_release_metadata = true;
1278 }
1279
1280 num_pages = DIV_ROUND_UP(write_bytes + offset, PAGE_SIZE);
1281 WARN_ON(num_pages > nrptrs);
1282 reserve_bytes = round_up(write_bytes + sector_offset,
1283 fs_info->sectorsize);
1284 WARN_ON(reserve_bytes == 0);
1285 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
1286 reserve_bytes,
1287 reserve_bytes, nowait);
1288 if (ret) {
1289 if (!only_release_metadata)
1290 btrfs_free_reserved_data_space(BTRFS_I(inode),
1291 data_reserved, pos,
1292 write_bytes);
1293 else
1294 btrfs_check_nocow_unlock(BTRFS_I(inode));
1295
1296 if (nowait && ret == -ENOSPC)
1297 ret = -EAGAIN;
1298 break;
1299 }
1300
1301 release_bytes = reserve_bytes;
1302again:
1303 ret = balance_dirty_pages_ratelimited_flags(inode->i_mapping, bdp_flags);
1304 if (ret) {
1305 btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
1306 break;
1307 }
1308
1309 /*
1310 * This is going to setup the pages array with the number of
1311 * pages we want, so we don't really need to worry about the
1312 * contents of pages from loop to loop
1313 */
1314 ret = prepare_pages(inode, pages, num_pages,
1315 pos, write_bytes, force_page_uptodate, false);
1316 if (ret) {
1317 btrfs_delalloc_release_extents(BTRFS_I(inode),
1318 reserve_bytes);
1319 break;
1320 }
1321
1322 extents_locked = lock_and_cleanup_extent_if_need(
1323 BTRFS_I(inode), pages,
1324 num_pages, pos, write_bytes, &lockstart,
1325 &lockend, nowait, &cached_state);
1326 if (extents_locked < 0) {
1327 if (!nowait && extents_locked == -EAGAIN)
1328 goto again;
1329
1330 btrfs_delalloc_release_extents(BTRFS_I(inode),
1331 reserve_bytes);
1332 ret = extents_locked;
1333 break;
1334 }
1335
1336 copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
1337
1338 num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
1339 dirty_sectors = round_up(copied + sector_offset,
1340 fs_info->sectorsize);
1341 dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors);
1342
1343 /*
1344 * if we have trouble faulting in the pages, fall
1345 * back to one page at a time
1346 */
1347 if (copied < write_bytes)
1348 nrptrs = 1;
1349
1350 if (copied == 0) {
1351 force_page_uptodate = true;
1352 dirty_sectors = 0;
1353 dirty_pages = 0;
1354 } else {
1355 force_page_uptodate = false;
1356 dirty_pages = DIV_ROUND_UP(copied + offset,
1357 PAGE_SIZE);
1358 }
1359
1360 if (num_sectors > dirty_sectors) {
1361 /* release everything except the sectors we dirtied */
1362 release_bytes -= dirty_sectors << fs_info->sectorsize_bits;
1363 if (only_release_metadata) {
1364 btrfs_delalloc_release_metadata(BTRFS_I(inode),
1365 release_bytes, true);
1366 } else {
1367 u64 __pos;
1368
1369 __pos = round_down(pos,
1370 fs_info->sectorsize) +
1371 (dirty_pages << PAGE_SHIFT);
1372 btrfs_delalloc_release_space(BTRFS_I(inode),
1373 data_reserved, __pos,
1374 release_bytes, true);
1375 }
1376 }
1377
1378 release_bytes = round_up(copied + sector_offset,
1379 fs_info->sectorsize);
1380
1381 ret = btrfs_dirty_pages(BTRFS_I(inode), pages,
1382 dirty_pages, pos, copied,
1383 &cached_state, only_release_metadata);
1384
1385 /*
1386 * If we have not locked the extent range, because the range's
1387 * start offset is >= i_size, we might still have a non-NULL
1388 * cached extent state, acquired while marking the extent range
1389 * as delalloc through btrfs_dirty_pages(). Therefore free any
1390 * possible cached extent state to avoid a memory leak.
1391 */
1392 if (extents_locked)
1393 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart,
1394 lockend, &cached_state);
1395 else
1396 free_extent_state(cached_state);
1397
1398 btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
1399 if (ret) {
1400 btrfs_drop_pages(fs_info, pages, num_pages, pos, copied);
1401 break;
1402 }
1403
1404 release_bytes = 0;
1405 if (only_release_metadata)
1406 btrfs_check_nocow_unlock(BTRFS_I(inode));
1407
1408 btrfs_drop_pages(fs_info, pages, num_pages, pos, copied);
1409
1410 cond_resched();
1411
1412 pos += copied;
1413 num_written += copied;
1414 }
1415
1416 kfree(pages);
1417
1418 if (release_bytes) {
1419 if (only_release_metadata) {
1420 btrfs_check_nocow_unlock(BTRFS_I(inode));
1421 btrfs_delalloc_release_metadata(BTRFS_I(inode),
1422 release_bytes, true);
1423 } else {
1424 btrfs_delalloc_release_space(BTRFS_I(inode),
1425 data_reserved,
1426 round_down(pos, fs_info->sectorsize),
1427 release_bytes, true);
1428 }
1429 }
1430
1431 extent_changeset_free(data_reserved);
1432 if (num_written > 0) {
1433 pagecache_isize_extended(inode, old_isize, iocb->ki_pos);
1434 iocb->ki_pos += num_written;
1435 }
1436out:
1437 btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1438 return num_written ? num_written : ret;
1439}
1440
1441static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
1442 const struct iov_iter *iter, loff_t offset)
1443{
1444 const u32 blocksize_mask = fs_info->sectorsize - 1;
1445
1446 if (offset & blocksize_mask)
1447 return -EINVAL;
1448
1449 if (iov_iter_alignment(iter) & blocksize_mask)
1450 return -EINVAL;
1451
1452 return 0;
1453}
1454
1455static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
1456{
1457 struct file *file = iocb->ki_filp;
1458 struct inode *inode = file_inode(file);
1459 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1460 loff_t pos;
1461 ssize_t written = 0;
1462 ssize_t written_buffered;
1463 size_t prev_left = 0;
1464 loff_t endbyte;
1465 ssize_t err;
1466 unsigned int ilock_flags = 0;
1467 struct iomap_dio *dio;
1468
1469 if (iocb->ki_flags & IOCB_NOWAIT)
1470 ilock_flags |= BTRFS_ILOCK_TRY;
1471
1472 /* If the write DIO is within EOF, use a shared lock */
1473 if (iocb->ki_pos + iov_iter_count(from) <= i_size_read(inode))
1474 ilock_flags |= BTRFS_ILOCK_SHARED;
1475
1476relock:
1477 err = btrfs_inode_lock(BTRFS_I(inode), ilock_flags);
1478 if (err < 0)
1479 return err;
1480
1481 err = generic_write_checks(iocb, from);
1482 if (err <= 0) {
1483 btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1484 return err;
1485 }
1486
1487 err = btrfs_write_check(iocb, from, err);
1488 if (err < 0) {
1489 btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1490 goto out;
1491 }
1492
1493 pos = iocb->ki_pos;
1494 /*
1495 * Re-check since file size may have changed just before taking the
1496 * lock or pos may have changed because of O_APPEND in generic_write_check()
1497 */
1498 if ((ilock_flags & BTRFS_ILOCK_SHARED) &&
1499 pos + iov_iter_count(from) > i_size_read(inode)) {
1500 btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1501 ilock_flags &= ~BTRFS_ILOCK_SHARED;
1502 goto relock;
1503 }
1504
1505 if (check_direct_IO(fs_info, from, pos)) {
1506 btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1507 goto buffered;
1508 }
1509
1510 /*
1511 * The iov_iter can be mapped to the same file range we are writing to.
1512 * If that's the case, then we will deadlock in the iomap code, because
1513 * it first calls our callback btrfs_dio_iomap_begin(), which will create
1514 * an ordered extent, and after that it will fault in the pages that the
1515 * iov_iter refers to. During the fault in we end up in the readahead
1516 * pages code (starting at btrfs_readahead()), which will lock the range,
1517 * find that ordered extent and then wait for it to complete (at
1518 * btrfs_lock_and_flush_ordered_range()), resulting in a deadlock since
1519 * obviously the ordered extent can never complete as we didn't submit
1520 * yet the respective bio(s). This always happens when the buffer is
1521 * memory mapped to the same file range, since the iomap DIO code always
1522 * invalidates pages in the target file range (after starting and waiting
1523 * for any writeback).
1524 *
1525 * So here we disable page faults in the iov_iter and then retry if we
1526 * got -EFAULT, faulting in the pages before the retry.
1527 */
1528 from->nofault = true;
1529 dio = btrfs_dio_write(iocb, from, written);
1530 from->nofault = false;
1531
1532 /*
1533 * iomap_dio_complete() will call btrfs_sync_file() if we have a dsync
1534 * iocb, and that needs to lock the inode. So unlock it before calling
1535 * iomap_dio_complete() to avoid a deadlock.
1536 */
1537 btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1538
1539 if (IS_ERR_OR_NULL(dio))
1540 err = PTR_ERR_OR_ZERO(dio);
1541 else
1542 err = iomap_dio_complete(dio);
1543
1544 /* No increment (+=) because iomap returns a cumulative value. */
1545 if (err > 0)
1546 written = err;
1547
1548 if (iov_iter_count(from) > 0 && (err == -EFAULT || err > 0)) {
1549 const size_t left = iov_iter_count(from);
1550 /*
1551 * We have more data left to write. Try to fault in as many as
1552 * possible of the remainder pages and retry. We do this without
1553 * releasing and locking again the inode, to prevent races with
1554 * truncate.
1555 *
1556 * Also, in case the iov refers to pages in the file range of the
1557 * file we want to write to (due to a mmap), we could enter an
1558 * infinite loop if we retry after faulting the pages in, since
1559 * iomap will invalidate any pages in the range early on, before
1560 * it tries to fault in the pages of the iov. So we keep track of
1561 * how much was left of iov in the previous EFAULT and fallback
1562 * to buffered IO in case we haven't made any progress.
1563 */
1564 if (left == prev_left) {
1565 err = -ENOTBLK;
1566 } else {
1567 fault_in_iov_iter_readable(from, left);
1568 prev_left = left;
1569 goto relock;
1570 }
1571 }
1572
1573 /*
1574 * If 'err' is -ENOTBLK or we have not written all data, then it means
1575 * we must fallback to buffered IO.
1576 */
1577 if ((err < 0 && err != -ENOTBLK) || !iov_iter_count(from))
1578 goto out;
1579
1580buffered:
1581 /*
1582 * If we are in a NOWAIT context, then return -EAGAIN to signal the caller
1583 * it must retry the operation in a context where blocking is acceptable,
1584 * because even if we end up not blocking during the buffered IO attempt
1585 * below, we will block when flushing and waiting for the IO.
1586 */
1587 if (iocb->ki_flags & IOCB_NOWAIT) {
1588 err = -EAGAIN;
1589 goto out;
1590 }
1591
1592 pos = iocb->ki_pos;
1593 written_buffered = btrfs_buffered_write(iocb, from);
1594 if (written_buffered < 0) {
1595 err = written_buffered;
1596 goto out;
1597 }
1598 /*
1599 * Ensure all data is persisted. We want the next direct IO read to be
1600 * able to read what was just written.
1601 */
1602 endbyte = pos + written_buffered - 1;
1603 err = btrfs_fdatawrite_range(inode, pos, endbyte);
1604 if (err)
1605 goto out;
1606 err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
1607 if (err)
1608 goto out;
1609 written += written_buffered;
1610 iocb->ki_pos = pos + written_buffered;
1611 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT,
1612 endbyte >> PAGE_SHIFT);
1613out:
1614 return err < 0 ? err : written;
1615}
1616
1617static ssize_t btrfs_encoded_write(struct kiocb *iocb, struct iov_iter *from,
1618 const struct btrfs_ioctl_encoded_io_args *encoded)
1619{
1620 struct file *file = iocb->ki_filp;
1621 struct inode *inode = file_inode(file);
1622 loff_t count;
1623 ssize_t ret;
1624
1625 btrfs_inode_lock(BTRFS_I(inode), 0);
1626 count = encoded->len;
1627 ret = generic_write_checks_count(iocb, &count);
1628 if (ret == 0 && count != encoded->len) {
1629 /*
1630 * The write got truncated by generic_write_checks_count(). We
1631 * can't do a partial encoded write.
1632 */
1633 ret = -EFBIG;
1634 }
1635 if (ret || encoded->len == 0)
1636 goto out;
1637
1638 ret = btrfs_write_check(iocb, from, encoded->len);
1639 if (ret < 0)
1640 goto out;
1641
1642 ret = btrfs_do_encoded_write(iocb, from, encoded);
1643out:
1644 btrfs_inode_unlock(BTRFS_I(inode), 0);
1645 return ret;
1646}
1647
1648ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
1649 const struct btrfs_ioctl_encoded_io_args *encoded)
1650{
1651 struct file *file = iocb->ki_filp;
1652 struct btrfs_inode *inode = BTRFS_I(file_inode(file));
1653 ssize_t num_written, num_sync;
1654 const bool sync = iocb_is_dsync(iocb);
1655
1656 /*
1657 * If the fs flips readonly due to some impossible error, although we
1658 * have opened a file as writable, we have to stop this write operation
1659 * to ensure consistency.
1660 */
1661 if (BTRFS_FS_ERROR(inode->root->fs_info))
1662 return -EROFS;
1663
1664 if (encoded && (iocb->ki_flags & IOCB_NOWAIT))
1665 return -EOPNOTSUPP;
1666
1667 if (sync)
1668 atomic_inc(&inode->sync_writers);
1669
1670 if (encoded) {
1671 num_written = btrfs_encoded_write(iocb, from, encoded);
1672 num_sync = encoded->len;
1673 } else if (iocb->ki_flags & IOCB_DIRECT) {
1674 num_written = btrfs_direct_write(iocb, from);
1675 num_sync = num_written;
1676 } else {
1677 num_written = btrfs_buffered_write(iocb, from);
1678 num_sync = num_written;
1679 }
1680
1681 btrfs_set_inode_last_sub_trans(inode);
1682
1683 if (num_sync > 0) {
1684 num_sync = generic_write_sync(iocb, num_sync);
1685 if (num_sync < 0)
1686 num_written = num_sync;
1687 }
1688
1689 if (sync)
1690 atomic_dec(&inode->sync_writers);
1691
1692 current->backing_dev_info = NULL;
1693 return num_written;
1694}
1695
1696static ssize_t btrfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1697{
1698 return btrfs_do_write_iter(iocb, from, NULL);
1699}
1700
1701int btrfs_release_file(struct inode *inode, struct file *filp)
1702{
1703 struct btrfs_file_private *private = filp->private_data;
1704
1705 if (private) {
1706 kfree(private->filldir_buf);
1707 free_extent_state(private->llseek_cached_state);
1708 kfree(private);
1709 filp->private_data = NULL;
1710 }
1711
1712 /*
1713 * Set by setattr when we are about to truncate a file from a non-zero
1714 * size to a zero size. This tries to flush down new bytes that may
1715 * have been written if the application were using truncate to replace
1716 * a file in place.
1717 */
1718 if (test_and_clear_bit(BTRFS_INODE_FLUSH_ON_CLOSE,
1719 &BTRFS_I(inode)->runtime_flags))
1720 filemap_flush(inode->i_mapping);
1721 return 0;
1722}
1723
1724static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
1725{
1726 int ret;
1727 struct blk_plug plug;
1728
1729 /*
1730 * This is only called in fsync, which would do synchronous writes, so
1731 * a plug can merge adjacent IOs as much as possible. Esp. in case of
1732 * multiple disks using raid profile, a large IO can be split to
1733 * several segments of stripe length (currently 64K).
1734 */
1735 blk_start_plug(&plug);
1736 atomic_inc(&BTRFS_I(inode)->sync_writers);
1737 ret = btrfs_fdatawrite_range(inode, start, end);
1738 atomic_dec(&BTRFS_I(inode)->sync_writers);
1739 blk_finish_plug(&plug);
1740
1741 return ret;
1742}
1743
1744static inline bool skip_inode_logging(const struct btrfs_log_ctx *ctx)
1745{
1746 struct btrfs_inode *inode = BTRFS_I(ctx->inode);
1747 struct btrfs_fs_info *fs_info = inode->root->fs_info;
1748
1749 if (btrfs_inode_in_log(inode, fs_info->generation) &&
1750 list_empty(&ctx->ordered_extents))
1751 return true;
1752
1753 /*
1754 * If we are doing a fast fsync we can not bail out if the inode's
1755 * last_trans is <= then the last committed transaction, because we only
1756 * update the last_trans of the inode during ordered extent completion,
1757 * and for a fast fsync we don't wait for that, we only wait for the
1758 * writeback to complete.
1759 */
1760 if (inode->last_trans <= fs_info->last_trans_committed &&
1761 (test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags) ||
1762 list_empty(&ctx->ordered_extents)))
1763 return true;
1764
1765 return false;
1766}
1767
1768/*
1769 * fsync call for both files and directories. This logs the inode into
1770 * the tree log instead of forcing full commits whenever possible.
1771 *
1772 * It needs to call filemap_fdatawait so that all ordered extent updates are
1773 * in the metadata btree are up to date for copying to the log.
1774 *
1775 * It drops the inode mutex before doing the tree log commit. This is an
1776 * important optimization for directories because holding the mutex prevents
1777 * new operations on the dir while we write to disk.
1778 */
1779int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1780{
1781 struct dentry *dentry = file_dentry(file);
1782 struct inode *inode = d_inode(dentry);
1783 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1784 struct btrfs_root *root = BTRFS_I(inode)->root;
1785 struct btrfs_trans_handle *trans;
1786 struct btrfs_log_ctx ctx;
1787 int ret = 0, err;
1788 u64 len;
1789 bool full_sync;
1790
1791 trace_btrfs_sync_file(file, datasync);
1792
1793 btrfs_init_log_ctx(&ctx, inode);
1794
1795 /*
1796 * Always set the range to a full range, otherwise we can get into
1797 * several problems, from missing file extent items to represent holes
1798 * when not using the NO_HOLES feature, to log tree corruption due to
1799 * races between hole detection during logging and completion of ordered
1800 * extents outside the range, to missing checksums due to ordered extents
1801 * for which we flushed only a subset of their pages.
1802 */
1803 start = 0;
1804 end = LLONG_MAX;
1805 len = (u64)LLONG_MAX + 1;
1806
1807 /*
1808 * We write the dirty pages in the range and wait until they complete
1809 * out of the ->i_mutex. If so, we can flush the dirty pages by
1810 * multi-task, and make the performance up. See
1811 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1812 */
1813 ret = start_ordered_ops(inode, start, end);
1814 if (ret)
1815 goto out;
1816
1817 btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
1818
1819 atomic_inc(&root->log_batch);
1820
1821 /*
1822 * Before we acquired the inode's lock and the mmap lock, someone may
1823 * have dirtied more pages in the target range. We need to make sure
1824 * that writeback for any such pages does not start while we are logging
1825 * the inode, because if it does, any of the following might happen when
1826 * we are not doing a full inode sync:
1827 *
1828 * 1) We log an extent after its writeback finishes but before its
1829 * checksums are added to the csum tree, leading to -EIO errors
1830 * when attempting to read the extent after a log replay.
1831 *
1832 * 2) We can end up logging an extent before its writeback finishes.
1833 * Therefore after the log replay we will have a file extent item
1834 * pointing to an unwritten extent (and no data checksums as well).
1835 *
1836 * So trigger writeback for any eventual new dirty pages and then we
1837 * wait for all ordered extents to complete below.
1838 */
1839 ret = start_ordered_ops(inode, start, end);
1840 if (ret) {
1841 btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
1842 goto out;
1843 }
1844
1845 /*
1846 * Always check for the full sync flag while holding the inode's lock,
1847 * to avoid races with other tasks. The flag must be either set all the
1848 * time during logging or always off all the time while logging.
1849 * We check the flag here after starting delalloc above, because when
1850 * running delalloc the full sync flag may be set if we need to drop
1851 * extra extent map ranges due to temporary memory allocation failures.
1852 */
1853 full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1854 &BTRFS_I(inode)->runtime_flags);
1855
1856 /*
1857 * We have to do this here to avoid the priority inversion of waiting on
1858 * IO of a lower priority task while holding a transaction open.
1859 *
1860 * For a full fsync we wait for the ordered extents to complete while
1861 * for a fast fsync we wait just for writeback to complete, and then
1862 * attach the ordered extents to the transaction so that a transaction
1863 * commit waits for their completion, to avoid data loss if we fsync,
1864 * the current transaction commits before the ordered extents complete
1865 * and a power failure happens right after that.
1866 *
1867 * For zoned filesystem, if a write IO uses a ZONE_APPEND command, the
1868 * logical address recorded in the ordered extent may change. We need
1869 * to wait for the IO to stabilize the logical address.
1870 */
1871 if (full_sync || btrfs_is_zoned(fs_info)) {
1872 ret = btrfs_wait_ordered_range(inode, start, len);
1873 } else {
1874 /*
1875 * Get our ordered extents as soon as possible to avoid doing
1876 * checksum lookups in the csum tree, and use instead the
1877 * checksums attached to the ordered extents.
1878 */
1879 btrfs_get_ordered_extents_for_logging(BTRFS_I(inode),
1880 &ctx.ordered_extents);
1881 ret = filemap_fdatawait_range(inode->i_mapping, start, end);
1882 }
1883
1884 if (ret)
1885 goto out_release_extents;
1886
1887 atomic_inc(&root->log_batch);
1888
1889 smp_mb();
1890 if (skip_inode_logging(&ctx)) {
1891 /*
1892 * We've had everything committed since the last time we were
1893 * modified so clear this flag in case it was set for whatever
1894 * reason, it's no longer relevant.
1895 */
1896 clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1897 &BTRFS_I(inode)->runtime_flags);
1898 /*
1899 * An ordered extent might have started before and completed
1900 * already with io errors, in which case the inode was not
1901 * updated and we end up here. So check the inode's mapping
1902 * for any errors that might have happened since we last
1903 * checked called fsync.
1904 */
1905 ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
1906 goto out_release_extents;
1907 }
1908
1909 /*
1910 * We use start here because we will need to wait on the IO to complete
1911 * in btrfs_sync_log, which could require joining a transaction (for
1912 * example checking cross references in the nocow path). If we use join
1913 * here we could get into a situation where we're waiting on IO to
1914 * happen that is blocked on a transaction trying to commit. With start
1915 * we inc the extwriter counter, so we wait for all extwriters to exit
1916 * before we start blocking joiners. This comment is to keep somebody
1917 * from thinking they are super smart and changing this to
1918 * btrfs_join_transaction *cough*Josef*cough*.
1919 */
1920 trans = btrfs_start_transaction(root, 0);
1921 if (IS_ERR(trans)) {
1922 ret = PTR_ERR(trans);
1923 goto out_release_extents;
1924 }
1925 trans->in_fsync = true;
1926
1927 ret = btrfs_log_dentry_safe(trans, dentry, &ctx);
1928 btrfs_release_log_ctx_extents(&ctx);
1929 if (ret < 0) {
1930 /* Fallthrough and commit/free transaction. */
1931 ret = BTRFS_LOG_FORCE_COMMIT;
1932 }
1933
1934 /* we've logged all the items and now have a consistent
1935 * version of the file in the log. It is possible that
1936 * someone will come in and modify the file, but that's
1937 * fine because the log is consistent on disk, and we
1938 * have references to all of the file's extents
1939 *
1940 * It is possible that someone will come in and log the
1941 * file again, but that will end up using the synchronization
1942 * inside btrfs_sync_log to keep things safe.
1943 */
1944 btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
1945
1946 if (ret == BTRFS_NO_LOG_SYNC) {
1947 ret = btrfs_end_transaction(trans);
1948 goto out;
1949 }
1950
1951 /* We successfully logged the inode, attempt to sync the log. */
1952 if (!ret) {
1953 ret = btrfs_sync_log(trans, root, &ctx);
1954 if (!ret) {
1955 ret = btrfs_end_transaction(trans);
1956 goto out;
1957 }
1958 }
1959
1960 /*
1961 * At this point we need to commit the transaction because we had
1962 * btrfs_need_log_full_commit() or some other error.
1963 *
1964 * If we didn't do a full sync we have to stop the trans handle, wait on
1965 * the ordered extents, start it again and commit the transaction. If
1966 * we attempt to wait on the ordered extents here we could deadlock with
1967 * something like fallocate() that is holding the extent lock trying to
1968 * start a transaction while some other thread is trying to commit the
1969 * transaction while we (fsync) are currently holding the transaction
1970 * open.
1971 */
1972 if (!full_sync) {
1973 ret = btrfs_end_transaction(trans);
1974 if (ret)
1975 goto out;
1976 ret = btrfs_wait_ordered_range(inode, start, len);
1977 if (ret)
1978 goto out;
1979
1980 /*
1981 * This is safe to use here because we're only interested in
1982 * making sure the transaction that had the ordered extents is
1983 * committed. We aren't waiting on anything past this point,
1984 * we're purely getting the transaction and committing it.
1985 */
1986 trans = btrfs_attach_transaction_barrier(root);
1987 if (IS_ERR(trans)) {
1988 ret = PTR_ERR(trans);
1989
1990 /*
1991 * We committed the transaction and there's no currently
1992 * running transaction, this means everything we care
1993 * about made it to disk and we are done.
1994 */
1995 if (ret == -ENOENT)
1996 ret = 0;
1997 goto out;
1998 }
1999 }
2000
2001 ret = btrfs_commit_transaction(trans);
2002out:
2003 ASSERT(list_empty(&ctx.list));
2004 ASSERT(list_empty(&ctx.conflict_inodes));
2005 err = file_check_and_advance_wb_err(file);
2006 if (!ret)
2007 ret = err;
2008 return ret > 0 ? -EIO : ret;
2009
2010out_release_extents:
2011 btrfs_release_log_ctx_extents(&ctx);
2012 btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
2013 goto out;
2014}
2015
2016static const struct vm_operations_struct btrfs_file_vm_ops = {
2017 .fault = filemap_fault,
2018 .map_pages = filemap_map_pages,
2019 .page_mkwrite = btrfs_page_mkwrite,
2020};
2021
2022static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
2023{
2024 struct address_space *mapping = filp->f_mapping;
2025
2026 if (!mapping->a_ops->read_folio)
2027 return -ENOEXEC;
2028
2029 file_accessed(filp);
2030 vma->vm_ops = &btrfs_file_vm_ops;
2031
2032 return 0;
2033}
2034
2035static int hole_mergeable(struct btrfs_inode *inode, struct extent_buffer *leaf,
2036 int slot, u64 start, u64 end)
2037{
2038 struct btrfs_file_extent_item *fi;
2039 struct btrfs_key key;
2040
2041 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
2042 return 0;
2043
2044 btrfs_item_key_to_cpu(leaf, &key, slot);
2045 if (key.objectid != btrfs_ino(inode) ||
2046 key.type != BTRFS_EXTENT_DATA_KEY)
2047 return 0;
2048
2049 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2050
2051 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2052 return 0;
2053
2054 if (btrfs_file_extent_disk_bytenr(leaf, fi))
2055 return 0;
2056
2057 if (key.offset == end)
2058 return 1;
2059 if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
2060 return 1;
2061 return 0;
2062}
2063
2064static int fill_holes(struct btrfs_trans_handle *trans,
2065 struct btrfs_inode *inode,
2066 struct btrfs_path *path, u64 offset, u64 end)
2067{
2068 struct btrfs_fs_info *fs_info = trans->fs_info;
2069 struct btrfs_root *root = inode->root;
2070 struct extent_buffer *leaf;
2071 struct btrfs_file_extent_item *fi;
2072 struct extent_map *hole_em;
2073 struct btrfs_key key;
2074 int ret;
2075
2076 if (btrfs_fs_incompat(fs_info, NO_HOLES))
2077 goto out;
2078
2079 key.objectid = btrfs_ino(inode);
2080 key.type = BTRFS_EXTENT_DATA_KEY;
2081 key.offset = offset;
2082
2083 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2084 if (ret <= 0) {
2085 /*
2086 * We should have dropped this offset, so if we find it then
2087 * something has gone horribly wrong.
2088 */
2089 if (ret == 0)
2090 ret = -EINVAL;
2091 return ret;
2092 }
2093
2094 leaf = path->nodes[0];
2095 if (hole_mergeable(inode, leaf, path->slots[0] - 1, offset, end)) {
2096 u64 num_bytes;
2097
2098 path->slots[0]--;
2099 fi = btrfs_item_ptr(leaf, path->slots[0],
2100 struct btrfs_file_extent_item);
2101 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
2102 end - offset;
2103 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2104 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2105 btrfs_set_file_extent_offset(leaf, fi, 0);
2106 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2107 btrfs_mark_buffer_dirty(leaf);
2108 goto out;
2109 }
2110
2111 if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
2112 u64 num_bytes;
2113
2114 key.offset = offset;
2115 btrfs_set_item_key_safe(fs_info, path, &key);
2116 fi = btrfs_item_ptr(leaf, path->slots[0],
2117 struct btrfs_file_extent_item);
2118 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
2119 offset;
2120 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2121 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2122 btrfs_set_file_extent_offset(leaf, fi, 0);
2123 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2124 btrfs_mark_buffer_dirty(leaf);
2125 goto out;
2126 }
2127 btrfs_release_path(path);
2128
2129 ret = btrfs_insert_hole_extent(trans, root, btrfs_ino(inode), offset,
2130 end - offset);
2131 if (ret)
2132 return ret;
2133
2134out:
2135 btrfs_release_path(path);
2136
2137 hole_em = alloc_extent_map();
2138 if (!hole_em) {
2139 btrfs_drop_extent_map_range(inode, offset, end - 1, false);
2140 btrfs_set_inode_full_sync(inode);
2141 } else {
2142 hole_em->start = offset;
2143 hole_em->len = end - offset;
2144 hole_em->ram_bytes = hole_em->len;
2145 hole_em->orig_start = offset;
2146
2147 hole_em->block_start = EXTENT_MAP_HOLE;
2148 hole_em->block_len = 0;
2149 hole_em->orig_block_len = 0;
2150 hole_em->compress_type = BTRFS_COMPRESS_NONE;
2151 hole_em->generation = trans->transid;
2152
2153 ret = btrfs_replace_extent_map_range(inode, hole_em, true);
2154 free_extent_map(hole_em);
2155 if (ret)
2156 btrfs_set_inode_full_sync(inode);
2157 }
2158
2159 return 0;
2160}
2161
2162/*
2163 * Find a hole extent on given inode and change start/len to the end of hole
2164 * extent.(hole/vacuum extent whose em->start <= start &&
2165 * em->start + em->len > start)
2166 * When a hole extent is found, return 1 and modify start/len.
2167 */
2168static int find_first_non_hole(struct btrfs_inode *inode, u64 *start, u64 *len)
2169{
2170 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2171 struct extent_map *em;
2172 int ret = 0;
2173
2174 em = btrfs_get_extent(inode, NULL, 0,
2175 round_down(*start, fs_info->sectorsize),
2176 round_up(*len, fs_info->sectorsize));
2177 if (IS_ERR(em))
2178 return PTR_ERR(em);
2179
2180 /* Hole or vacuum extent(only exists in no-hole mode) */
2181 if (em->block_start == EXTENT_MAP_HOLE) {
2182 ret = 1;
2183 *len = em->start + em->len > *start + *len ?
2184 0 : *start + *len - em->start - em->len;
2185 *start = em->start + em->len;
2186 }
2187 free_extent_map(em);
2188 return ret;
2189}
2190
2191static void btrfs_punch_hole_lock_range(struct inode *inode,
2192 const u64 lockstart,
2193 const u64 lockend,
2194 struct extent_state **cached_state)
2195{
2196 /*
2197 * For subpage case, if the range is not at page boundary, we could
2198 * have pages at the leading/tailing part of the range.
2199 * This could lead to dead loop since filemap_range_has_page()
2200 * will always return true.
2201 * So here we need to do extra page alignment for
2202 * filemap_range_has_page().
2203 */
2204 const u64 page_lockstart = round_up(lockstart, PAGE_SIZE);
2205 const u64 page_lockend = round_down(lockend + 1, PAGE_SIZE) - 1;
2206
2207 while (1) {
2208 truncate_pagecache_range(inode, lockstart, lockend);
2209
2210 lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2211 cached_state);
2212 /*
2213 * We can't have ordered extents in the range, nor dirty/writeback
2214 * pages, because we have locked the inode's VFS lock in exclusive
2215 * mode, we have locked the inode's i_mmap_lock in exclusive mode,
2216 * we have flushed all delalloc in the range and we have waited
2217 * for any ordered extents in the range to complete.
2218 * We can race with anyone reading pages from this range, so after
2219 * locking the range check if we have pages in the range, and if
2220 * we do, unlock the range and retry.
2221 */
2222 if (!filemap_range_has_page(inode->i_mapping, page_lockstart,
2223 page_lockend))
2224 break;
2225
2226 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2227 cached_state);
2228 }
2229
2230 btrfs_assert_inode_range_clean(BTRFS_I(inode), lockstart, lockend);
2231}
2232
2233static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans,
2234 struct btrfs_inode *inode,
2235 struct btrfs_path *path,
2236 struct btrfs_replace_extent_info *extent_info,
2237 const u64 replace_len,
2238 const u64 bytes_to_drop)
2239{
2240 struct btrfs_fs_info *fs_info = trans->fs_info;
2241 struct btrfs_root *root = inode->root;
2242 struct btrfs_file_extent_item *extent;
2243 struct extent_buffer *leaf;
2244 struct btrfs_key key;
2245 int slot;
2246 struct btrfs_ref ref = { 0 };
2247 int ret;
2248
2249 if (replace_len == 0)
2250 return 0;
2251
2252 if (extent_info->disk_offset == 0 &&
2253 btrfs_fs_incompat(fs_info, NO_HOLES)) {
2254 btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
2255 return 0;
2256 }
2257
2258 key.objectid = btrfs_ino(inode);
2259 key.type = BTRFS_EXTENT_DATA_KEY;
2260 key.offset = extent_info->file_offset;
2261 ret = btrfs_insert_empty_item(trans, root, path, &key,
2262 sizeof(struct btrfs_file_extent_item));
2263 if (ret)
2264 return ret;
2265 leaf = path->nodes[0];
2266 slot = path->slots[0];
2267 write_extent_buffer(leaf, extent_info->extent_buf,
2268 btrfs_item_ptr_offset(leaf, slot),
2269 sizeof(struct btrfs_file_extent_item));
2270 extent = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2271 ASSERT(btrfs_file_extent_type(leaf, extent) != BTRFS_FILE_EXTENT_INLINE);
2272 btrfs_set_file_extent_offset(leaf, extent, extent_info->data_offset);
2273 btrfs_set_file_extent_num_bytes(leaf, extent, replace_len);
2274 if (extent_info->is_new_extent)
2275 btrfs_set_file_extent_generation(leaf, extent, trans->transid);
2276 btrfs_mark_buffer_dirty(leaf);
2277 btrfs_release_path(path);
2278
2279 ret = btrfs_inode_set_file_extent_range(inode, extent_info->file_offset,
2280 replace_len);
2281 if (ret)
2282 return ret;
2283
2284 /* If it's a hole, nothing more needs to be done. */
2285 if (extent_info->disk_offset == 0) {
2286 btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
2287 return 0;
2288 }
2289
2290 btrfs_update_inode_bytes(inode, replace_len, bytes_to_drop);
2291
2292 if (extent_info->is_new_extent && extent_info->insertions == 0) {
2293 key.objectid = extent_info->disk_offset;
2294 key.type = BTRFS_EXTENT_ITEM_KEY;
2295 key.offset = extent_info->disk_len;
2296 ret = btrfs_alloc_reserved_file_extent(trans, root,
2297 btrfs_ino(inode),
2298 extent_info->file_offset,
2299 extent_info->qgroup_reserved,
2300 &key);
2301 } else {
2302 u64 ref_offset;
2303
2304 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2305 extent_info->disk_offset,
2306 extent_info->disk_len, 0);
2307 ref_offset = extent_info->file_offset - extent_info->data_offset;
2308 btrfs_init_data_ref(&ref, root->root_key.objectid,
2309 btrfs_ino(inode), ref_offset, 0, false);
2310 ret = btrfs_inc_extent_ref(trans, &ref);
2311 }
2312
2313 extent_info->insertions++;
2314
2315 return ret;
2316}
2317
2318/*
2319 * The respective range must have been previously locked, as well as the inode.
2320 * The end offset is inclusive (last byte of the range).
2321 * @extent_info is NULL for fallocate's hole punching and non-NULL when replacing
2322 * the file range with an extent.
2323 * When not punching a hole, we don't want to end up in a state where we dropped
2324 * extents without inserting a new one, so we must abort the transaction to avoid
2325 * a corruption.
2326 */
2327int btrfs_replace_file_extents(struct btrfs_inode *inode,
2328 struct btrfs_path *path, const u64 start,
2329 const u64 end,
2330 struct btrfs_replace_extent_info *extent_info,
2331 struct btrfs_trans_handle **trans_out)
2332{
2333 struct btrfs_drop_extents_args drop_args = { 0 };
2334 struct btrfs_root *root = inode->root;
2335 struct btrfs_fs_info *fs_info = root->fs_info;
2336 u64 min_size = btrfs_calc_insert_metadata_size(fs_info, 1);
2337 u64 ino_size = round_up(inode->vfs_inode.i_size, fs_info->sectorsize);
2338 struct btrfs_trans_handle *trans = NULL;
2339 struct btrfs_block_rsv *rsv;
2340 unsigned int rsv_count;
2341 u64 cur_offset;
2342 u64 len = end - start;
2343 int ret = 0;
2344
2345 if (end <= start)
2346 return -EINVAL;
2347
2348 rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
2349 if (!rsv) {
2350 ret = -ENOMEM;
2351 goto out;
2352 }
2353 rsv->size = btrfs_calc_insert_metadata_size(fs_info, 1);
2354 rsv->failfast = true;
2355
2356 /*
2357 * 1 - update the inode
2358 * 1 - removing the extents in the range
2359 * 1 - adding the hole extent if no_holes isn't set or if we are
2360 * replacing the range with a new extent
2361 */
2362 if (!btrfs_fs_incompat(fs_info, NO_HOLES) || extent_info)
2363 rsv_count = 3;
2364 else
2365 rsv_count = 2;
2366
2367 trans = btrfs_start_transaction(root, rsv_count);
2368 if (IS_ERR(trans)) {
2369 ret = PTR_ERR(trans);
2370 trans = NULL;
2371 goto out_free;
2372 }
2373
2374 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
2375 min_size, false);
2376 if (WARN_ON(ret))
2377 goto out_trans;
2378 trans->block_rsv = rsv;
2379
2380 cur_offset = start;
2381 drop_args.path = path;
2382 drop_args.end = end + 1;
2383 drop_args.drop_cache = true;
2384 while (cur_offset < end) {
2385 drop_args.start = cur_offset;
2386 ret = btrfs_drop_extents(trans, root, inode, &drop_args);
2387 /* If we are punching a hole decrement the inode's byte count */
2388 if (!extent_info)
2389 btrfs_update_inode_bytes(inode, 0,
2390 drop_args.bytes_found);
2391 if (ret != -ENOSPC) {
2392 /*
2393 * The only time we don't want to abort is if we are
2394 * attempting to clone a partial inline extent, in which
2395 * case we'll get EOPNOTSUPP. However if we aren't
2396 * clone we need to abort no matter what, because if we
2397 * got EOPNOTSUPP via prealloc then we messed up and
2398 * need to abort.
2399 */
2400 if (ret &&
2401 (ret != -EOPNOTSUPP ||
2402 (extent_info && extent_info->is_new_extent)))
2403 btrfs_abort_transaction(trans, ret);
2404 break;
2405 }
2406
2407 trans->block_rsv = &fs_info->trans_block_rsv;
2408
2409 if (!extent_info && cur_offset < drop_args.drop_end &&
2410 cur_offset < ino_size) {
2411 ret = fill_holes(trans, inode, path, cur_offset,
2412 drop_args.drop_end);
2413 if (ret) {
2414 /*
2415 * If we failed then we didn't insert our hole
2416 * entries for the area we dropped, so now the
2417 * fs is corrupted, so we must abort the
2418 * transaction.
2419 */
2420 btrfs_abort_transaction(trans, ret);
2421 break;
2422 }
2423 } else if (!extent_info && cur_offset < drop_args.drop_end) {
2424 /*
2425 * We are past the i_size here, but since we didn't
2426 * insert holes we need to clear the mapped area so we
2427 * know to not set disk_i_size in this area until a new
2428 * file extent is inserted here.
2429 */
2430 ret = btrfs_inode_clear_file_extent_range(inode,
2431 cur_offset,
2432 drop_args.drop_end - cur_offset);
2433 if (ret) {
2434 /*
2435 * We couldn't clear our area, so we could
2436 * presumably adjust up and corrupt the fs, so
2437 * we need to abort.
2438 */
2439 btrfs_abort_transaction(trans, ret);
2440 break;
2441 }
2442 }
2443
2444 if (extent_info &&
2445 drop_args.drop_end > extent_info->file_offset) {
2446 u64 replace_len = drop_args.drop_end -
2447 extent_info->file_offset;
2448
2449 ret = btrfs_insert_replace_extent(trans, inode, path,
2450 extent_info, replace_len,
2451 drop_args.bytes_found);
2452 if (ret) {
2453 btrfs_abort_transaction(trans, ret);
2454 break;
2455 }
2456 extent_info->data_len -= replace_len;
2457 extent_info->data_offset += replace_len;
2458 extent_info->file_offset += replace_len;
2459 }
2460
2461 /*
2462 * We are releasing our handle on the transaction, balance the
2463 * dirty pages of the btree inode and flush delayed items, and
2464 * then get a new transaction handle, which may now point to a
2465 * new transaction in case someone else may have committed the
2466 * transaction we used to replace/drop file extent items. So
2467 * bump the inode's iversion and update mtime and ctime except
2468 * if we are called from a dedupe context. This is because a
2469 * power failure/crash may happen after the transaction is
2470 * committed and before we finish replacing/dropping all the
2471 * file extent items we need.
2472 */
2473 inode_inc_iversion(&inode->vfs_inode);
2474
2475 if (!extent_info || extent_info->update_times) {
2476 inode->vfs_inode.i_mtime = current_time(&inode->vfs_inode);
2477 inode->vfs_inode.i_ctime = inode->vfs_inode.i_mtime;
2478 }
2479
2480 ret = btrfs_update_inode(trans, root, inode);
2481 if (ret)
2482 break;
2483
2484 btrfs_end_transaction(trans);
2485 btrfs_btree_balance_dirty(fs_info);
2486
2487 trans = btrfs_start_transaction(root, rsv_count);
2488 if (IS_ERR(trans)) {
2489 ret = PTR_ERR(trans);
2490 trans = NULL;
2491 break;
2492 }
2493
2494 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
2495 rsv, min_size, false);
2496 if (WARN_ON(ret))
2497 break;
2498 trans->block_rsv = rsv;
2499
2500 cur_offset = drop_args.drop_end;
2501 len = end - cur_offset;
2502 if (!extent_info && len) {
2503 ret = find_first_non_hole(inode, &cur_offset, &len);
2504 if (unlikely(ret < 0))
2505 break;
2506 if (ret && !len) {
2507 ret = 0;
2508 break;
2509 }
2510 }
2511 }
2512
2513 /*
2514 * If we were cloning, force the next fsync to be a full one since we
2515 * we replaced (or just dropped in the case of cloning holes when
2516 * NO_HOLES is enabled) file extent items and did not setup new extent
2517 * maps for the replacement extents (or holes).
2518 */
2519 if (extent_info && !extent_info->is_new_extent)
2520 btrfs_set_inode_full_sync(inode);
2521
2522 if (ret)
2523 goto out_trans;
2524
2525 trans->block_rsv = &fs_info->trans_block_rsv;
2526 /*
2527 * If we are using the NO_HOLES feature we might have had already an
2528 * hole that overlaps a part of the region [lockstart, lockend] and
2529 * ends at (or beyond) lockend. Since we have no file extent items to
2530 * represent holes, drop_end can be less than lockend and so we must
2531 * make sure we have an extent map representing the existing hole (the
2532 * call to __btrfs_drop_extents() might have dropped the existing extent
2533 * map representing the existing hole), otherwise the fast fsync path
2534 * will not record the existence of the hole region
2535 * [existing_hole_start, lockend].
2536 */
2537 if (drop_args.drop_end <= end)
2538 drop_args.drop_end = end + 1;
2539 /*
2540 * Don't insert file hole extent item if it's for a range beyond eof
2541 * (because it's useless) or if it represents a 0 bytes range (when
2542 * cur_offset == drop_end).
2543 */
2544 if (!extent_info && cur_offset < ino_size &&
2545 cur_offset < drop_args.drop_end) {
2546 ret = fill_holes(trans, inode, path, cur_offset,
2547 drop_args.drop_end);
2548 if (ret) {
2549 /* Same comment as above. */
2550 btrfs_abort_transaction(trans, ret);
2551 goto out_trans;
2552 }
2553 } else if (!extent_info && cur_offset < drop_args.drop_end) {
2554 /* See the comment in the loop above for the reasoning here. */
2555 ret = btrfs_inode_clear_file_extent_range(inode, cur_offset,
2556 drop_args.drop_end - cur_offset);
2557 if (ret) {
2558 btrfs_abort_transaction(trans, ret);
2559 goto out_trans;
2560 }
2561
2562 }
2563 if (extent_info) {
2564 ret = btrfs_insert_replace_extent(trans, inode, path,
2565 extent_info, extent_info->data_len,
2566 drop_args.bytes_found);
2567 if (ret) {
2568 btrfs_abort_transaction(trans, ret);
2569 goto out_trans;
2570 }
2571 }
2572
2573out_trans:
2574 if (!trans)
2575 goto out_free;
2576
2577 trans->block_rsv = &fs_info->trans_block_rsv;
2578 if (ret)
2579 btrfs_end_transaction(trans);
2580 else
2581 *trans_out = trans;
2582out_free:
2583 btrfs_free_block_rsv(fs_info, rsv);
2584out:
2585 return ret;
2586}
2587
2588static int btrfs_punch_hole(struct file *file, loff_t offset, loff_t len)
2589{
2590 struct inode *inode = file_inode(file);
2591 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2592 struct btrfs_root *root = BTRFS_I(inode)->root;
2593 struct extent_state *cached_state = NULL;
2594 struct btrfs_path *path;
2595 struct btrfs_trans_handle *trans = NULL;
2596 u64 lockstart;
2597 u64 lockend;
2598 u64 tail_start;
2599 u64 tail_len;
2600 u64 orig_start = offset;
2601 int ret = 0;
2602 bool same_block;
2603 u64 ino_size;
2604 bool truncated_block = false;
2605 bool updated_inode = false;
2606
2607 btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
2608
2609 ret = btrfs_wait_ordered_range(inode, offset, len);
2610 if (ret)
2611 goto out_only_mutex;
2612
2613 ino_size = round_up(inode->i_size, fs_info->sectorsize);
2614 ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
2615 if (ret < 0)
2616 goto out_only_mutex;
2617 if (ret && !len) {
2618 /* Already in a large hole */
2619 ret = 0;
2620 goto out_only_mutex;
2621 }
2622
2623 ret = file_modified(file);
2624 if (ret)
2625 goto out_only_mutex;
2626
2627 lockstart = round_up(offset, fs_info->sectorsize);
2628 lockend = round_down(offset + len, fs_info->sectorsize) - 1;
2629 same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset))
2630 == (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1));
2631 /*
2632 * We needn't truncate any block which is beyond the end of the file
2633 * because we are sure there is no data there.
2634 */
2635 /*
2636 * Only do this if we are in the same block and we aren't doing the
2637 * entire block.
2638 */
2639 if (same_block && len < fs_info->sectorsize) {
2640 if (offset < ino_size) {
2641 truncated_block = true;
2642 ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
2643 0);
2644 } else {
2645 ret = 0;
2646 }
2647 goto out_only_mutex;
2648 }
2649
2650 /* zero back part of the first block */
2651 if (offset < ino_size) {
2652 truncated_block = true;
2653 ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
2654 if (ret) {
2655 btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
2656 return ret;
2657 }
2658 }
2659
2660 /* Check the aligned pages after the first unaligned page,
2661 * if offset != orig_start, which means the first unaligned page
2662 * including several following pages are already in holes,
2663 * the extra check can be skipped */
2664 if (offset == orig_start) {
2665 /* after truncate page, check hole again */
2666 len = offset + len - lockstart;
2667 offset = lockstart;
2668 ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
2669 if (ret < 0)
2670 goto out_only_mutex;
2671 if (ret && !len) {
2672 ret = 0;
2673 goto out_only_mutex;
2674 }
2675 lockstart = offset;
2676 }
2677
2678 /* Check the tail unaligned part is in a hole */
2679 tail_start = lockend + 1;
2680 tail_len = offset + len - tail_start;
2681 if (tail_len) {
2682 ret = find_first_non_hole(BTRFS_I(inode), &tail_start, &tail_len);
2683 if (unlikely(ret < 0))
2684 goto out_only_mutex;
2685 if (!ret) {
2686 /* zero the front end of the last page */
2687 if (tail_start + tail_len < ino_size) {
2688 truncated_block = true;
2689 ret = btrfs_truncate_block(BTRFS_I(inode),
2690 tail_start + tail_len,
2691 0, 1);
2692 if (ret)
2693 goto out_only_mutex;
2694 }
2695 }
2696 }
2697
2698 if (lockend < lockstart) {
2699 ret = 0;
2700 goto out_only_mutex;
2701 }
2702
2703 btrfs_punch_hole_lock_range(inode, lockstart, lockend, &cached_state);
2704
2705 path = btrfs_alloc_path();
2706 if (!path) {
2707 ret = -ENOMEM;
2708 goto out;
2709 }
2710
2711 ret = btrfs_replace_file_extents(BTRFS_I(inode), path, lockstart,
2712 lockend, NULL, &trans);
2713 btrfs_free_path(path);
2714 if (ret)
2715 goto out;
2716
2717 ASSERT(trans != NULL);
2718 inode_inc_iversion(inode);
2719 inode->i_mtime = current_time(inode);
2720 inode->i_ctime = inode->i_mtime;
2721 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2722 updated_inode = true;
2723 btrfs_end_transaction(trans);
2724 btrfs_btree_balance_dirty(fs_info);
2725out:
2726 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2727 &cached_state);
2728out_only_mutex:
2729 if (!updated_inode && truncated_block && !ret) {
2730 /*
2731 * If we only end up zeroing part of a page, we still need to
2732 * update the inode item, so that all the time fields are
2733 * updated as well as the necessary btrfs inode in memory fields
2734 * for detecting, at fsync time, if the inode isn't yet in the
2735 * log tree or it's there but not up to date.
2736 */
2737 struct timespec64 now = current_time(inode);
2738
2739 inode_inc_iversion(inode);
2740 inode->i_mtime = now;
2741 inode->i_ctime = now;
2742 trans = btrfs_start_transaction(root, 1);
2743 if (IS_ERR(trans)) {
2744 ret = PTR_ERR(trans);
2745 } else {
2746 int ret2;
2747
2748 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2749 ret2 = btrfs_end_transaction(trans);
2750 if (!ret)
2751 ret = ret2;
2752 }
2753 }
2754 btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
2755 return ret;
2756}
2757
2758/* Helper structure to record which range is already reserved */
2759struct falloc_range {
2760 struct list_head list;
2761 u64 start;
2762 u64 len;
2763};
2764
2765/*
2766 * Helper function to add falloc range
2767 *
2768 * Caller should have locked the larger range of extent containing
2769 * [start, len)
2770 */
2771static int add_falloc_range(struct list_head *head, u64 start, u64 len)
2772{
2773 struct falloc_range *range = NULL;
2774
2775 if (!list_empty(head)) {
2776 /*
2777 * As fallocate iterates by bytenr order, we only need to check
2778 * the last range.
2779 */
2780 range = list_last_entry(head, struct falloc_range, list);
2781 if (range->start + range->len == start) {
2782 range->len += len;
2783 return 0;
2784 }
2785 }
2786
2787 range = kmalloc(sizeof(*range), GFP_KERNEL);
2788 if (!range)
2789 return -ENOMEM;
2790 range->start = start;
2791 range->len = len;
2792 list_add_tail(&range->list, head);
2793 return 0;
2794}
2795
2796static int btrfs_fallocate_update_isize(struct inode *inode,
2797 const u64 end,
2798 const int mode)
2799{
2800 struct btrfs_trans_handle *trans;
2801 struct btrfs_root *root = BTRFS_I(inode)->root;
2802 int ret;
2803 int ret2;
2804
2805 if (mode & FALLOC_FL_KEEP_SIZE || end <= i_size_read(inode))
2806 return 0;
2807
2808 trans = btrfs_start_transaction(root, 1);
2809 if (IS_ERR(trans))
2810 return PTR_ERR(trans);
2811
2812 inode->i_ctime = current_time(inode);
2813 i_size_write(inode, end);
2814 btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
2815 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2816 ret2 = btrfs_end_transaction(trans);
2817
2818 return ret ? ret : ret2;
2819}
2820
2821enum {
2822 RANGE_BOUNDARY_WRITTEN_EXTENT,
2823 RANGE_BOUNDARY_PREALLOC_EXTENT,
2824 RANGE_BOUNDARY_HOLE,
2825};
2826
2827static int btrfs_zero_range_check_range_boundary(struct btrfs_inode *inode,
2828 u64 offset)
2829{
2830 const u64 sectorsize = inode->root->fs_info->sectorsize;
2831 struct extent_map *em;
2832 int ret;
2833
2834 offset = round_down(offset, sectorsize);
2835 em = btrfs_get_extent(inode, NULL, 0, offset, sectorsize);
2836 if (IS_ERR(em))
2837 return PTR_ERR(em);
2838
2839 if (em->block_start == EXTENT_MAP_HOLE)
2840 ret = RANGE_BOUNDARY_HOLE;
2841 else if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2842 ret = RANGE_BOUNDARY_PREALLOC_EXTENT;
2843 else
2844 ret = RANGE_BOUNDARY_WRITTEN_EXTENT;
2845
2846 free_extent_map(em);
2847 return ret;
2848}
2849
2850static int btrfs_zero_range(struct inode *inode,
2851 loff_t offset,
2852 loff_t len,
2853 const int mode)
2854{
2855 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2856 struct extent_map *em;
2857 struct extent_changeset *data_reserved = NULL;
2858 int ret;
2859 u64 alloc_hint = 0;
2860 const u64 sectorsize = fs_info->sectorsize;
2861 u64 alloc_start = round_down(offset, sectorsize);
2862 u64 alloc_end = round_up(offset + len, sectorsize);
2863 u64 bytes_to_reserve = 0;
2864 bool space_reserved = false;
2865
2866 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
2867 alloc_end - alloc_start);
2868 if (IS_ERR(em)) {
2869 ret = PTR_ERR(em);
2870 goto out;
2871 }
2872
2873 /*
2874 * Avoid hole punching and extent allocation for some cases. More cases
2875 * could be considered, but these are unlikely common and we keep things
2876 * as simple as possible for now. Also, intentionally, if the target
2877 * range contains one or more prealloc extents together with regular
2878 * extents and holes, we drop all the existing extents and allocate a
2879 * new prealloc extent, so that we get a larger contiguous disk extent.
2880 */
2881 if (em->start <= alloc_start &&
2882 test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
2883 const u64 em_end = em->start + em->len;
2884
2885 if (em_end >= offset + len) {
2886 /*
2887 * The whole range is already a prealloc extent,
2888 * do nothing except updating the inode's i_size if
2889 * needed.
2890 */
2891 free_extent_map(em);
2892 ret = btrfs_fallocate_update_isize(inode, offset + len,
2893 mode);
2894 goto out;
2895 }
2896 /*
2897 * Part of the range is already a prealloc extent, so operate
2898 * only on the remaining part of the range.
2899 */
2900 alloc_start = em_end;
2901 ASSERT(IS_ALIGNED(alloc_start, sectorsize));
2902 len = offset + len - alloc_start;
2903 offset = alloc_start;
2904 alloc_hint = em->block_start + em->len;
2905 }
2906 free_extent_map(em);
2907
2908 if (BTRFS_BYTES_TO_BLKS(fs_info, offset) ==
2909 BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)) {
2910 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
2911 sectorsize);
2912 if (IS_ERR(em)) {
2913 ret = PTR_ERR(em);
2914 goto out;
2915 }
2916
2917 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
2918 free_extent_map(em);
2919 ret = btrfs_fallocate_update_isize(inode, offset + len,
2920 mode);
2921 goto out;
2922 }
2923 if (len < sectorsize && em->block_start != EXTENT_MAP_HOLE) {
2924 free_extent_map(em);
2925 ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
2926 0);
2927 if (!ret)
2928 ret = btrfs_fallocate_update_isize(inode,
2929 offset + len,
2930 mode);
2931 return ret;
2932 }
2933 free_extent_map(em);
2934 alloc_start = round_down(offset, sectorsize);
2935 alloc_end = alloc_start + sectorsize;
2936 goto reserve_space;
2937 }
2938
2939 alloc_start = round_up(offset, sectorsize);
2940 alloc_end = round_down(offset + len, sectorsize);
2941
2942 /*
2943 * For unaligned ranges, check the pages at the boundaries, they might
2944 * map to an extent, in which case we need to partially zero them, or
2945 * they might map to a hole, in which case we need our allocation range
2946 * to cover them.
2947 */
2948 if (!IS_ALIGNED(offset, sectorsize)) {
2949 ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
2950 offset);
2951 if (ret < 0)
2952 goto out;
2953 if (ret == RANGE_BOUNDARY_HOLE) {
2954 alloc_start = round_down(offset, sectorsize);
2955 ret = 0;
2956 } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
2957 ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
2958 if (ret)
2959 goto out;
2960 } else {
2961 ret = 0;
2962 }
2963 }
2964
2965 if (!IS_ALIGNED(offset + len, sectorsize)) {
2966 ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
2967 offset + len);
2968 if (ret < 0)
2969 goto out;
2970 if (ret == RANGE_BOUNDARY_HOLE) {
2971 alloc_end = round_up(offset + len, sectorsize);
2972 ret = 0;
2973 } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
2974 ret = btrfs_truncate_block(BTRFS_I(inode), offset + len,
2975 0, 1);
2976 if (ret)
2977 goto out;
2978 } else {
2979 ret = 0;
2980 }
2981 }
2982
2983reserve_space:
2984 if (alloc_start < alloc_end) {
2985 struct extent_state *cached_state = NULL;
2986 const u64 lockstart = alloc_start;
2987 const u64 lockend = alloc_end - 1;
2988
2989 bytes_to_reserve = alloc_end - alloc_start;
2990 ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
2991 bytes_to_reserve);
2992 if (ret < 0)
2993 goto out;
2994 space_reserved = true;
2995 btrfs_punch_hole_lock_range(inode, lockstart, lockend,
2996 &cached_state);
2997 ret = btrfs_qgroup_reserve_data(BTRFS_I(inode), &data_reserved,
2998 alloc_start, bytes_to_reserve);
2999 if (ret) {
3000 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart,
3001 lockend, &cached_state);
3002 goto out;
3003 }
3004 ret = btrfs_prealloc_file_range(inode, mode, alloc_start,
3005 alloc_end - alloc_start,
3006 i_blocksize(inode),
3007 offset + len, &alloc_hint);
3008 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
3009 &cached_state);
3010 /* btrfs_prealloc_file_range releases reserved space on error */
3011 if (ret) {
3012 space_reserved = false;
3013 goto out;
3014 }
3015 }
3016 ret = btrfs_fallocate_update_isize(inode, offset + len, mode);
3017 out:
3018 if (ret && space_reserved)
3019 btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved,
3020 alloc_start, bytes_to_reserve);
3021 extent_changeset_free(data_reserved);
3022
3023 return ret;
3024}
3025
3026static long btrfs_fallocate(struct file *file, int mode,
3027 loff_t offset, loff_t len)
3028{
3029 struct inode *inode = file_inode(file);
3030 struct extent_state *cached_state = NULL;
3031 struct extent_changeset *data_reserved = NULL;
3032 struct falloc_range *range;
3033 struct falloc_range *tmp;
3034 struct list_head reserve_list;
3035 u64 cur_offset;
3036 u64 last_byte;
3037 u64 alloc_start;
3038 u64 alloc_end;
3039 u64 alloc_hint = 0;
3040 u64 locked_end;
3041 u64 actual_end = 0;
3042 u64 data_space_needed = 0;
3043 u64 data_space_reserved = 0;
3044 u64 qgroup_reserved = 0;
3045 struct extent_map *em;
3046 int blocksize = BTRFS_I(inode)->root->fs_info->sectorsize;
3047 int ret;
3048
3049 /* Do not allow fallocate in ZONED mode */
3050 if (btrfs_is_zoned(btrfs_sb(inode->i_sb)))
3051 return -EOPNOTSUPP;
3052
3053 alloc_start = round_down(offset, blocksize);
3054 alloc_end = round_up(offset + len, blocksize);
3055 cur_offset = alloc_start;
3056
3057 /* Make sure we aren't being give some crap mode */
3058 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
3059 FALLOC_FL_ZERO_RANGE))
3060 return -EOPNOTSUPP;
3061
3062 if (mode & FALLOC_FL_PUNCH_HOLE)
3063 return btrfs_punch_hole(file, offset, len);
3064
3065 btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
3066
3067 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) {
3068 ret = inode_newsize_ok(inode, offset + len);
3069 if (ret)
3070 goto out;
3071 }
3072
3073 ret = file_modified(file);
3074 if (ret)
3075 goto out;
3076
3077 /*
3078 * TODO: Move these two operations after we have checked
3079 * accurate reserved space, or fallocate can still fail but
3080 * with page truncated or size expanded.
3081 *
3082 * But that's a minor problem and won't do much harm BTW.
3083 */
3084 if (alloc_start > inode->i_size) {
3085 ret = btrfs_cont_expand(BTRFS_I(inode), i_size_read(inode),
3086 alloc_start);
3087 if (ret)
3088 goto out;
3089 } else if (offset + len > inode->i_size) {
3090 /*
3091 * If we are fallocating from the end of the file onward we
3092 * need to zero out the end of the block if i_size lands in the
3093 * middle of a block.
3094 */
3095 ret = btrfs_truncate_block(BTRFS_I(inode), inode->i_size, 0, 0);
3096 if (ret)
3097 goto out;
3098 }
3099
3100 /*
3101 * We have locked the inode at the VFS level (in exclusive mode) and we
3102 * have locked the i_mmap_lock lock (in exclusive mode). Now before
3103 * locking the file range, flush all dealloc in the range and wait for
3104 * all ordered extents in the range to complete. After this we can lock
3105 * the file range and, due to the previous locking we did, we know there
3106 * can't be more delalloc or ordered extents in the range.
3107 */
3108 ret = btrfs_wait_ordered_range(inode, alloc_start,
3109 alloc_end - alloc_start);
3110 if (ret)
3111 goto out;
3112
3113 if (mode & FALLOC_FL_ZERO_RANGE) {
3114 ret = btrfs_zero_range(inode, offset, len, mode);
3115 btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
3116 return ret;
3117 }
3118
3119 locked_end = alloc_end - 1;
3120 lock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
3121 &cached_state);
3122
3123 btrfs_assert_inode_range_clean(BTRFS_I(inode), alloc_start, locked_end);
3124
3125 /* First, check if we exceed the qgroup limit */
3126 INIT_LIST_HEAD(&reserve_list);
3127 while (cur_offset < alloc_end) {
3128 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
3129 alloc_end - cur_offset);
3130 if (IS_ERR(em)) {
3131 ret = PTR_ERR(em);
3132 break;
3133 }
3134 last_byte = min(extent_map_end(em), alloc_end);
3135 actual_end = min_t(u64, extent_map_end(em), offset + len);
3136 last_byte = ALIGN(last_byte, blocksize);
3137 if (em->block_start == EXTENT_MAP_HOLE ||
3138 (cur_offset >= inode->i_size &&
3139 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
3140 const u64 range_len = last_byte - cur_offset;
3141
3142 ret = add_falloc_range(&reserve_list, cur_offset, range_len);
3143 if (ret < 0) {
3144 free_extent_map(em);
3145 break;
3146 }
3147 ret = btrfs_qgroup_reserve_data(BTRFS_I(inode),
3148 &data_reserved, cur_offset, range_len);
3149 if (ret < 0) {
3150 free_extent_map(em);
3151 break;
3152 }
3153 qgroup_reserved += range_len;
3154 data_space_needed += range_len;
3155 }
3156 free_extent_map(em);
3157 cur_offset = last_byte;
3158 }
3159
3160 if (!ret && data_space_needed > 0) {
3161 /*
3162 * We are safe to reserve space here as we can't have delalloc
3163 * in the range, see above.
3164 */
3165 ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
3166 data_space_needed);
3167 if (!ret)
3168 data_space_reserved = data_space_needed;
3169 }
3170
3171 /*
3172 * If ret is still 0, means we're OK to fallocate.
3173 * Or just cleanup the list and exit.
3174 */
3175 list_for_each_entry_safe(range, tmp, &reserve_list, list) {
3176 if (!ret) {
3177 ret = btrfs_prealloc_file_range(inode, mode,
3178 range->start,
3179 range->len, i_blocksize(inode),
3180 offset + len, &alloc_hint);
3181 /*
3182 * btrfs_prealloc_file_range() releases space even
3183 * if it returns an error.
3184 */
3185 data_space_reserved -= range->len;
3186 qgroup_reserved -= range->len;
3187 } else if (data_space_reserved > 0) {
3188 btrfs_free_reserved_data_space(BTRFS_I(inode),
3189 data_reserved, range->start,
3190 range->len);
3191 data_space_reserved -= range->len;
3192 qgroup_reserved -= range->len;
3193 } else if (qgroup_reserved > 0) {
3194 btrfs_qgroup_free_data(BTRFS_I(inode), data_reserved,
3195 range->start, range->len);
3196 qgroup_reserved -= range->len;
3197 }
3198 list_del(&range->list);
3199 kfree(range);
3200 }
3201 if (ret < 0)
3202 goto out_unlock;
3203
3204 /*
3205 * We didn't need to allocate any more space, but we still extended the
3206 * size of the file so we need to update i_size and the inode item.
3207 */
3208 ret = btrfs_fallocate_update_isize(inode, actual_end, mode);
3209out_unlock:
3210 unlock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
3211 &cached_state);
3212out:
3213 btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
3214 extent_changeset_free(data_reserved);
3215 return ret;
3216}
3217
3218/*
3219 * Helper for btrfs_find_delalloc_in_range(). Find a subrange in a given range
3220 * that has unflushed and/or flushing delalloc. There might be other adjacent
3221 * subranges after the one it found, so btrfs_find_delalloc_in_range() keeps
3222 * looping while it gets adjacent subranges, and merging them together.
3223 */
3224static bool find_delalloc_subrange(struct btrfs_inode *inode, u64 start, u64 end,
3225 struct extent_state **cached_state,
3226 bool *search_io_tree,
3227 u64 *delalloc_start_ret, u64 *delalloc_end_ret)
3228{
3229 u64 len = end + 1 - start;
3230 u64 delalloc_len = 0;
3231 struct btrfs_ordered_extent *oe;
3232 u64 oe_start;
3233 u64 oe_end;
3234
3235 /*
3236 * Search the io tree first for EXTENT_DELALLOC. If we find any, it
3237 * means we have delalloc (dirty pages) for which writeback has not
3238 * started yet.
3239 */
3240 if (*search_io_tree) {
3241 spin_lock(&inode->lock);
3242 if (inode->delalloc_bytes > 0) {
3243 spin_unlock(&inode->lock);
3244 *delalloc_start_ret = start;
3245 delalloc_len = count_range_bits(&inode->io_tree,
3246 delalloc_start_ret, end,
3247 len, EXTENT_DELALLOC, 1,
3248 cached_state);
3249 } else {
3250 spin_unlock(&inode->lock);
3251 }
3252 }
3253
3254 if (delalloc_len > 0) {
3255 /*
3256 * If delalloc was found then *delalloc_start_ret has a sector size
3257 * aligned value (rounded down).
3258 */
3259 *delalloc_end_ret = *delalloc_start_ret + delalloc_len - 1;
3260
3261 if (*delalloc_start_ret == start) {
3262 /* Delalloc for the whole range, nothing more to do. */
3263 if (*delalloc_end_ret == end)
3264 return true;
3265 /* Else trim our search range for ordered extents. */
3266 start = *delalloc_end_ret + 1;
3267 len = end + 1 - start;
3268 }
3269 } else {
3270 /* No delalloc, future calls don't need to search again. */
3271 *search_io_tree = false;
3272 }
3273
3274 /*
3275 * Now also check if there's any ordered extent in the range.
3276 * We do this because:
3277 *
3278 * 1) When delalloc is flushed, the file range is locked, we clear the
3279 * EXTENT_DELALLOC bit from the io tree and create an extent map and
3280 * an ordered extent for the write. So we might just have been called
3281 * after delalloc is flushed and before the ordered extent completes
3282 * and inserts the new file extent item in the subvolume's btree;
3283 *
3284 * 2) We may have an ordered extent created by flushing delalloc for a
3285 * subrange that starts before the subrange we found marked with
3286 * EXTENT_DELALLOC in the io tree.
3287 *
3288 * We could also use the extent map tree to find such delalloc that is
3289 * being flushed, but using the ordered extents tree is more efficient
3290 * because it's usually much smaller as ordered extents are removed from
3291 * the tree once they complete. With the extent maps, we mau have them
3292 * in the extent map tree for a very long time, and they were either
3293 * created by previous writes or loaded by read operations.
3294 */
3295 oe = btrfs_lookup_first_ordered_range(inode, start, len);
3296 if (!oe)
3297 return (delalloc_len > 0);
3298
3299 /* The ordered extent may span beyond our search range. */
3300 oe_start = max(oe->file_offset, start);
3301 oe_end = min(oe->file_offset + oe->num_bytes - 1, end);
3302
3303 btrfs_put_ordered_extent(oe);
3304
3305 /* Don't have unflushed delalloc, return the ordered extent range. */
3306 if (delalloc_len == 0) {
3307 *delalloc_start_ret = oe_start;
3308 *delalloc_end_ret = oe_end;
3309 return true;
3310 }
3311
3312 /*
3313 * We have both unflushed delalloc (io_tree) and an ordered extent.
3314 * If the ranges are adjacent returned a combined range, otherwise
3315 * return the leftmost range.
3316 */
3317 if (oe_start < *delalloc_start_ret) {
3318 if (oe_end < *delalloc_start_ret)
3319 *delalloc_end_ret = oe_end;
3320 *delalloc_start_ret = oe_start;
3321 } else if (*delalloc_end_ret + 1 == oe_start) {
3322 *delalloc_end_ret = oe_end;
3323 }
3324
3325 return true;
3326}
3327
3328/*
3329 * Check if there's delalloc in a given range.
3330 *
3331 * @inode: The inode.
3332 * @start: The start offset of the range. It does not need to be
3333 * sector size aligned.
3334 * @end: The end offset (inclusive value) of the search range.
3335 * It does not need to be sector size aligned.
3336 * @cached_state: Extent state record used for speeding up delalloc
3337 * searches in the inode's io_tree. Can be NULL.
3338 * @delalloc_start_ret: Output argument, set to the start offset of the
3339 * subrange found with delalloc (may not be sector size
3340 * aligned).
3341 * @delalloc_end_ret: Output argument, set to he end offset (inclusive value)
3342 * of the subrange found with delalloc.
3343 *
3344 * Returns true if a subrange with delalloc is found within the given range, and
3345 * if so it sets @delalloc_start_ret and @delalloc_end_ret with the start and
3346 * end offsets of the subrange.
3347 */
3348bool btrfs_find_delalloc_in_range(struct btrfs_inode *inode, u64 start, u64 end,
3349 struct extent_state **cached_state,
3350 u64 *delalloc_start_ret, u64 *delalloc_end_ret)
3351{
3352 u64 cur_offset = round_down(start, inode->root->fs_info->sectorsize);
3353 u64 prev_delalloc_end = 0;
3354 bool search_io_tree = true;
3355 bool ret = false;
3356
3357 while (cur_offset <= end) {
3358 u64 delalloc_start;
3359 u64 delalloc_end;
3360 bool delalloc;
3361
3362 delalloc = find_delalloc_subrange(inode, cur_offset, end,
3363 cached_state, &search_io_tree,
3364 &delalloc_start,
3365 &delalloc_end);
3366 if (!delalloc)
3367 break;
3368
3369 if (prev_delalloc_end == 0) {
3370 /* First subrange found. */
3371 *delalloc_start_ret = max(delalloc_start, start);
3372 *delalloc_end_ret = delalloc_end;
3373 ret = true;
3374 } else if (delalloc_start == prev_delalloc_end + 1) {
3375 /* Subrange adjacent to the previous one, merge them. */
3376 *delalloc_end_ret = delalloc_end;
3377 } else {
3378 /* Subrange not adjacent to the previous one, exit. */
3379 break;
3380 }
3381
3382 prev_delalloc_end = delalloc_end;
3383 cur_offset = delalloc_end + 1;
3384 cond_resched();
3385 }
3386
3387 return ret;
3388}
3389
3390/*
3391 * Check if there's a hole or delalloc range in a range representing a hole (or
3392 * prealloc extent) found in the inode's subvolume btree.
3393 *
3394 * @inode: The inode.
3395 * @whence: Seek mode (SEEK_DATA or SEEK_HOLE).
3396 * @start: Start offset of the hole region. It does not need to be sector
3397 * size aligned.
3398 * @end: End offset (inclusive value) of the hole region. It does not
3399 * need to be sector size aligned.
3400 * @start_ret: Return parameter, used to set the start of the subrange in the
3401 * hole that matches the search criteria (seek mode), if such
3402 * subrange is found (return value of the function is true).
3403 * The value returned here may not be sector size aligned.
3404 *
3405 * Returns true if a subrange matching the given seek mode is found, and if one
3406 * is found, it updates @start_ret with the start of the subrange.
3407 */
3408static bool find_desired_extent_in_hole(struct btrfs_inode *inode, int whence,
3409 struct extent_state **cached_state,
3410 u64 start, u64 end, u64 *start_ret)
3411{
3412 u64 delalloc_start;
3413 u64 delalloc_end;
3414 bool delalloc;
3415
3416 delalloc = btrfs_find_delalloc_in_range(inode, start, end, cached_state,
3417 &delalloc_start, &delalloc_end);
3418 if (delalloc && whence == SEEK_DATA) {
3419 *start_ret = delalloc_start;
3420 return true;
3421 }
3422
3423 if (delalloc && whence == SEEK_HOLE) {
3424 /*
3425 * We found delalloc but it starts after out start offset. So we
3426 * have a hole between our start offset and the delalloc start.
3427 */
3428 if (start < delalloc_start) {
3429 *start_ret = start;
3430 return true;
3431 }
3432 /*
3433 * Delalloc range starts at our start offset.
3434 * If the delalloc range's length is smaller than our range,
3435 * then it means we have a hole that starts where the delalloc
3436 * subrange ends.
3437 */
3438 if (delalloc_end < end) {
3439 *start_ret = delalloc_end + 1;
3440 return true;
3441 }
3442
3443 /* There's delalloc for the whole range. */
3444 return false;
3445 }
3446
3447 if (!delalloc && whence == SEEK_HOLE) {
3448 *start_ret = start;
3449 return true;
3450 }
3451
3452 /*
3453 * No delalloc in the range and we are seeking for data. The caller has
3454 * to iterate to the next extent item in the subvolume btree.
3455 */
3456 return false;
3457}
3458
3459static loff_t find_desired_extent(struct file *file, loff_t offset, int whence)
3460{
3461 struct btrfs_inode *inode = BTRFS_I(file->f_mapping->host);
3462 struct btrfs_file_private *private = file->private_data;
3463 struct btrfs_fs_info *fs_info = inode->root->fs_info;
3464 struct extent_state *cached_state = NULL;
3465 struct extent_state **delalloc_cached_state;
3466 const loff_t i_size = i_size_read(&inode->vfs_inode);
3467 const u64 ino = btrfs_ino(inode);
3468 struct btrfs_root *root = inode->root;
3469 struct btrfs_path *path;
3470 struct btrfs_key key;
3471 u64 last_extent_end;
3472 u64 lockstart;
3473 u64 lockend;
3474 u64 start;
3475 int ret;
3476 bool found = false;
3477
3478 if (i_size == 0 || offset >= i_size)
3479 return -ENXIO;
3480
3481 /*
3482 * Quick path. If the inode has no prealloc extents and its number of
3483 * bytes used matches its i_size, then it can not have holes.
3484 */
3485 if (whence == SEEK_HOLE &&
3486 !(inode->flags & BTRFS_INODE_PREALLOC) &&
3487 inode_get_bytes(&inode->vfs_inode) == i_size)
3488 return i_size;
3489
3490 if (!private) {
3491 private = kzalloc(sizeof(*private), GFP_KERNEL);
3492 /*
3493 * No worries if memory allocation failed.
3494 * The private structure is used only for speeding up multiple
3495 * lseek SEEK_HOLE/DATA calls to a file when there's delalloc,
3496 * so everything will still be correct.
3497 */
3498 file->private_data = private;
3499 }
3500
3501 if (private)
3502 delalloc_cached_state = &private->llseek_cached_state;
3503 else
3504 delalloc_cached_state = NULL;
3505
3506 /*
3507 * offset can be negative, in this case we start finding DATA/HOLE from
3508 * the very start of the file.
3509 */
3510 start = max_t(loff_t, 0, offset);
3511
3512 lockstart = round_down(start, fs_info->sectorsize);
3513 lockend = round_up(i_size, fs_info->sectorsize);
3514 if (lockend <= lockstart)
3515 lockend = lockstart + fs_info->sectorsize;
3516 lockend--;
3517
3518 path = btrfs_alloc_path();
3519 if (!path)
3520 return -ENOMEM;
3521 path->reada = READA_FORWARD;
3522
3523 key.objectid = ino;
3524 key.type = BTRFS_EXTENT_DATA_KEY;
3525 key.offset = start;
3526
3527 last_extent_end = lockstart;
3528
3529 lock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
3530
3531 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3532 if (ret < 0) {
3533 goto out;
3534 } else if (ret > 0 && path->slots[0] > 0) {
3535 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1);
3536 if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY)
3537 path->slots[0]--;
3538 }
3539
3540 while (start < i_size) {
3541 struct extent_buffer *leaf = path->nodes[0];
3542 struct btrfs_file_extent_item *extent;
3543 u64 extent_end;
3544 u8 type;
3545
3546 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3547 ret = btrfs_next_leaf(root, path);
3548 if (ret < 0)
3549 goto out;
3550 else if (ret > 0)
3551 break;
3552
3553 leaf = path->nodes[0];
3554 }
3555
3556 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3557 if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY)
3558 break;
3559
3560 extent_end = btrfs_file_extent_end(path);
3561
3562 /*
3563 * In the first iteration we may have a slot that points to an
3564 * extent that ends before our start offset, so skip it.
3565 */
3566 if (extent_end <= start) {
3567 path->slots[0]++;
3568 continue;
3569 }
3570
3571 /* We have an implicit hole, NO_HOLES feature is likely set. */
3572 if (last_extent_end < key.offset) {
3573 u64 search_start = last_extent_end;
3574 u64 found_start;
3575
3576 /*
3577 * First iteration, @start matches @offset and it's
3578 * within the hole.
3579 */
3580 if (start == offset)
3581 search_start = offset;
3582
3583 found = find_desired_extent_in_hole(inode, whence,
3584 delalloc_cached_state,
3585 search_start,
3586 key.offset - 1,
3587 &found_start);
3588 if (found) {
3589 start = found_start;
3590 break;
3591 }
3592 /*
3593 * Didn't find data or a hole (due to delalloc) in the
3594 * implicit hole range, so need to analyze the extent.
3595 */
3596 }
3597
3598 extent = btrfs_item_ptr(leaf, path->slots[0],
3599 struct btrfs_file_extent_item);
3600 type = btrfs_file_extent_type(leaf, extent);
3601
3602 /*
3603 * Can't access the extent's disk_bytenr field if this is an
3604 * inline extent, since at that offset, it's where the extent
3605 * data starts.
3606 */
3607 if (type == BTRFS_FILE_EXTENT_PREALLOC ||
3608 (type == BTRFS_FILE_EXTENT_REG &&
3609 btrfs_file_extent_disk_bytenr(leaf, extent) == 0)) {
3610 /*
3611 * Explicit hole or prealloc extent, search for delalloc.
3612 * A prealloc extent is treated like a hole.
3613 */
3614 u64 search_start = key.offset;
3615 u64 found_start;
3616
3617 /*
3618 * First iteration, @start matches @offset and it's
3619 * within the hole.
3620 */
3621 if (start == offset)
3622 search_start = offset;
3623
3624 found = find_desired_extent_in_hole(inode, whence,
3625 delalloc_cached_state,
3626 search_start,
3627 extent_end - 1,
3628 &found_start);
3629 if (found) {
3630 start = found_start;
3631 break;
3632 }
3633 /*
3634 * Didn't find data or a hole (due to delalloc) in the
3635 * implicit hole range, so need to analyze the next
3636 * extent item.
3637 */
3638 } else {
3639 /*
3640 * Found a regular or inline extent.
3641 * If we are seeking for data, adjust the start offset
3642 * and stop, we're done.
3643 */
3644 if (whence == SEEK_DATA) {
3645 start = max_t(u64, key.offset, offset);
3646 found = true;
3647 break;
3648 }
3649 /*
3650 * Else, we are seeking for a hole, check the next file
3651 * extent item.
3652 */
3653 }
3654
3655 start = extent_end;
3656 last_extent_end = extent_end;
3657 path->slots[0]++;
3658 if (fatal_signal_pending(current)) {
3659 ret = -EINTR;
3660 goto out;
3661 }
3662 cond_resched();
3663 }
3664
3665 /* We have an implicit hole from the last extent found up to i_size. */
3666 if (!found && start < i_size) {
3667 found = find_desired_extent_in_hole(inode, whence,
3668 delalloc_cached_state, start,
3669 i_size - 1, &start);
3670 if (!found)
3671 start = i_size;
3672 }
3673
3674out:
3675 unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
3676 btrfs_free_path(path);
3677
3678 if (ret < 0)
3679 return ret;
3680
3681 if (whence == SEEK_DATA && start >= i_size)
3682 return -ENXIO;
3683
3684 return min_t(loff_t, start, i_size);
3685}
3686
3687static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
3688{
3689 struct inode *inode = file->f_mapping->host;
3690
3691 switch (whence) {
3692 default:
3693 return generic_file_llseek(file, offset, whence);
3694 case SEEK_DATA:
3695 case SEEK_HOLE:
3696 btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
3697 offset = find_desired_extent(file, offset, whence);
3698 btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
3699 break;
3700 }
3701
3702 if (offset < 0)
3703 return offset;
3704
3705 return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
3706}
3707
3708static int btrfs_file_open(struct inode *inode, struct file *filp)
3709{
3710 int ret;
3711
3712 filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC;
3713
3714 ret = fsverity_file_open(inode, filp);
3715 if (ret)
3716 return ret;
3717 return generic_file_open(inode, filp);
3718}
3719
3720static int check_direct_read(struct btrfs_fs_info *fs_info,
3721 const struct iov_iter *iter, loff_t offset)
3722{
3723 int ret;
3724 int i, seg;
3725
3726 ret = check_direct_IO(fs_info, iter, offset);
3727 if (ret < 0)
3728 return ret;
3729
3730 if (!iter_is_iovec(iter))
3731 return 0;
3732
3733 for (seg = 0; seg < iter->nr_segs; seg++)
3734 for (i = seg + 1; i < iter->nr_segs; i++)
3735 if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
3736 return -EINVAL;
3737 return 0;
3738}
3739
3740static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
3741{
3742 struct inode *inode = file_inode(iocb->ki_filp);
3743 size_t prev_left = 0;
3744 ssize_t read = 0;
3745 ssize_t ret;
3746
3747 if (fsverity_active(inode))
3748 return 0;
3749
3750 if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
3751 return 0;
3752
3753 btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
3754again:
3755 /*
3756 * This is similar to what we do for direct IO writes, see the comment
3757 * at btrfs_direct_write(), but we also disable page faults in addition
3758 * to disabling them only at the iov_iter level. This is because when
3759 * reading from a hole or prealloc extent, iomap calls iov_iter_zero(),
3760 * which can still trigger page fault ins despite having set ->nofault
3761 * to true of our 'to' iov_iter.
3762 *
3763 * The difference to direct IO writes is that we deadlock when trying
3764 * to lock the extent range in the inode's tree during he page reads
3765 * triggered by the fault in (while for writes it is due to waiting for
3766 * our own ordered extent). This is because for direct IO reads,
3767 * btrfs_dio_iomap_begin() returns with the extent range locked, which
3768 * is only unlocked in the endio callback (end_bio_extent_readpage()).
3769 */
3770 pagefault_disable();
3771 to->nofault = true;
3772 ret = btrfs_dio_read(iocb, to, read);
3773 to->nofault = false;
3774 pagefault_enable();
3775
3776 /* No increment (+=) because iomap returns a cumulative value. */
3777 if (ret > 0)
3778 read = ret;
3779
3780 if (iov_iter_count(to) > 0 && (ret == -EFAULT || ret > 0)) {
3781 const size_t left = iov_iter_count(to);
3782
3783 if (left == prev_left) {
3784 /*
3785 * We didn't make any progress since the last attempt,
3786 * fallback to a buffered read for the remainder of the
3787 * range. This is just to avoid any possibility of looping
3788 * for too long.
3789 */
3790 ret = read;
3791 } else {
3792 /*
3793 * We made some progress since the last retry or this is
3794 * the first time we are retrying. Fault in as many pages
3795 * as possible and retry.
3796 */
3797 fault_in_iov_iter_writeable(to, left);
3798 prev_left = left;
3799 goto again;
3800 }
3801 }
3802 btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
3803 return ret < 0 ? ret : read;
3804}
3805
3806static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
3807{
3808 ssize_t ret = 0;
3809
3810 if (iocb->ki_flags & IOCB_DIRECT) {
3811 ret = btrfs_direct_read(iocb, to);
3812 if (ret < 0 || !iov_iter_count(to) ||
3813 iocb->ki_pos >= i_size_read(file_inode(iocb->ki_filp)))
3814 return ret;
3815 }
3816
3817 return filemap_read(iocb, to, ret);
3818}
3819
3820const struct file_operations btrfs_file_operations = {
3821 .llseek = btrfs_file_llseek,
3822 .read_iter = btrfs_file_read_iter,
3823 .splice_read = generic_file_splice_read,
3824 .write_iter = btrfs_file_write_iter,
3825 .splice_write = iter_file_splice_write,
3826 .mmap = btrfs_file_mmap,
3827 .open = btrfs_file_open,
3828 .release = btrfs_release_file,
3829 .get_unmapped_area = thp_get_unmapped_area,
3830 .fsync = btrfs_sync_file,
3831 .fallocate = btrfs_fallocate,
3832 .unlocked_ioctl = btrfs_ioctl,
3833#ifdef CONFIG_COMPAT
3834 .compat_ioctl = btrfs_compat_ioctl,
3835#endif
3836 .remap_file_range = btrfs_remap_file_range,
3837};
3838
3839int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
3840{
3841 int ret;
3842
3843 /*
3844 * So with compression we will find and lock a dirty page and clear the
3845 * first one as dirty, setup an async extent, and immediately return
3846 * with the entire range locked but with nobody actually marked with
3847 * writeback. So we can't just filemap_write_and_wait_range() and
3848 * expect it to work since it will just kick off a thread to do the
3849 * actual work. So we need to call filemap_fdatawrite_range _again_
3850 * since it will wait on the page lock, which won't be unlocked until
3851 * after the pages have been marked as writeback and so we're good to go
3852 * from there. We have to do this otherwise we'll miss the ordered
3853 * extents and that results in badness. Please Josef, do not think you
3854 * know better and pull this out at some point in the future, it is
3855 * right and you are wrong.
3856 */
3857 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3858 if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
3859 &BTRFS_I(inode)->runtime_flags))
3860 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3861
3862 return ret;
3863}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <linux/fs.h>
7#include <linux/pagemap.h>
8#include <linux/time.h>
9#include <linux/init.h>
10#include <linux/string.h>
11#include <linux/backing-dev.h>
12#include <linux/falloc.h>
13#include <linux/writeback.h>
14#include <linux/compat.h>
15#include <linux/slab.h>
16#include <linux/btrfs.h>
17#include <linux/uio.h>
18#include <linux/iversion.h>
19#include "ctree.h"
20#include "disk-io.h"
21#include "transaction.h"
22#include "btrfs_inode.h"
23#include "print-tree.h"
24#include "tree-log.h"
25#include "locking.h"
26#include "volumes.h"
27#include "qgroup.h"
28#include "compression.h"
29#include "delalloc-space.h"
30#include "reflink.h"
31#include "subpage.h"
32
33static struct kmem_cache *btrfs_inode_defrag_cachep;
34/*
35 * when auto defrag is enabled we
36 * queue up these defrag structs to remember which
37 * inodes need defragging passes
38 */
39struct inode_defrag {
40 struct rb_node rb_node;
41 /* objectid */
42 u64 ino;
43 /*
44 * transid where the defrag was added, we search for
45 * extents newer than this
46 */
47 u64 transid;
48
49 /* root objectid */
50 u64 root;
51
52 /* last offset we were able to defrag */
53 u64 last_offset;
54
55 /* if we've wrapped around back to zero once already */
56 int cycled;
57};
58
59static int __compare_inode_defrag(struct inode_defrag *defrag1,
60 struct inode_defrag *defrag2)
61{
62 if (defrag1->root > defrag2->root)
63 return 1;
64 else if (defrag1->root < defrag2->root)
65 return -1;
66 else if (defrag1->ino > defrag2->ino)
67 return 1;
68 else if (defrag1->ino < defrag2->ino)
69 return -1;
70 else
71 return 0;
72}
73
74/* pop a record for an inode into the defrag tree. The lock
75 * must be held already
76 *
77 * If you're inserting a record for an older transid than an
78 * existing record, the transid already in the tree is lowered
79 *
80 * If an existing record is found the defrag item you
81 * pass in is freed
82 */
83static int __btrfs_add_inode_defrag(struct btrfs_inode *inode,
84 struct inode_defrag *defrag)
85{
86 struct btrfs_fs_info *fs_info = inode->root->fs_info;
87 struct inode_defrag *entry;
88 struct rb_node **p;
89 struct rb_node *parent = NULL;
90 int ret;
91
92 p = &fs_info->defrag_inodes.rb_node;
93 while (*p) {
94 parent = *p;
95 entry = rb_entry(parent, struct inode_defrag, rb_node);
96
97 ret = __compare_inode_defrag(defrag, entry);
98 if (ret < 0)
99 p = &parent->rb_left;
100 else if (ret > 0)
101 p = &parent->rb_right;
102 else {
103 /* if we're reinserting an entry for
104 * an old defrag run, make sure to
105 * lower the transid of our existing record
106 */
107 if (defrag->transid < entry->transid)
108 entry->transid = defrag->transid;
109 if (defrag->last_offset > entry->last_offset)
110 entry->last_offset = defrag->last_offset;
111 return -EEXIST;
112 }
113 }
114 set_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags);
115 rb_link_node(&defrag->rb_node, parent, p);
116 rb_insert_color(&defrag->rb_node, &fs_info->defrag_inodes);
117 return 0;
118}
119
120static inline int __need_auto_defrag(struct btrfs_fs_info *fs_info)
121{
122 if (!btrfs_test_opt(fs_info, AUTO_DEFRAG))
123 return 0;
124
125 if (btrfs_fs_closing(fs_info))
126 return 0;
127
128 return 1;
129}
130
131/*
132 * insert a defrag record for this inode if auto defrag is
133 * enabled
134 */
135int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
136 struct btrfs_inode *inode)
137{
138 struct btrfs_root *root = inode->root;
139 struct btrfs_fs_info *fs_info = root->fs_info;
140 struct inode_defrag *defrag;
141 u64 transid;
142 int ret;
143
144 if (!__need_auto_defrag(fs_info))
145 return 0;
146
147 if (test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags))
148 return 0;
149
150 if (trans)
151 transid = trans->transid;
152 else
153 transid = inode->root->last_trans;
154
155 defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
156 if (!defrag)
157 return -ENOMEM;
158
159 defrag->ino = btrfs_ino(inode);
160 defrag->transid = transid;
161 defrag->root = root->root_key.objectid;
162
163 spin_lock(&fs_info->defrag_inodes_lock);
164 if (!test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags)) {
165 /*
166 * If we set IN_DEFRAG flag and evict the inode from memory,
167 * and then re-read this inode, this new inode doesn't have
168 * IN_DEFRAG flag. At the case, we may find the existed defrag.
169 */
170 ret = __btrfs_add_inode_defrag(inode, defrag);
171 if (ret)
172 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
173 } else {
174 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
175 }
176 spin_unlock(&fs_info->defrag_inodes_lock);
177 return 0;
178}
179
180/*
181 * Requeue the defrag object. If there is a defrag object that points to
182 * the same inode in the tree, we will merge them together (by
183 * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
184 */
185static void btrfs_requeue_inode_defrag(struct btrfs_inode *inode,
186 struct inode_defrag *defrag)
187{
188 struct btrfs_fs_info *fs_info = inode->root->fs_info;
189 int ret;
190
191 if (!__need_auto_defrag(fs_info))
192 goto out;
193
194 /*
195 * Here we don't check the IN_DEFRAG flag, because we need merge
196 * them together.
197 */
198 spin_lock(&fs_info->defrag_inodes_lock);
199 ret = __btrfs_add_inode_defrag(inode, defrag);
200 spin_unlock(&fs_info->defrag_inodes_lock);
201 if (ret)
202 goto out;
203 return;
204out:
205 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
206}
207
208/*
209 * pick the defragable inode that we want, if it doesn't exist, we will get
210 * the next one.
211 */
212static struct inode_defrag *
213btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
214{
215 struct inode_defrag *entry = NULL;
216 struct inode_defrag tmp;
217 struct rb_node *p;
218 struct rb_node *parent = NULL;
219 int ret;
220
221 tmp.ino = ino;
222 tmp.root = root;
223
224 spin_lock(&fs_info->defrag_inodes_lock);
225 p = fs_info->defrag_inodes.rb_node;
226 while (p) {
227 parent = p;
228 entry = rb_entry(parent, struct inode_defrag, rb_node);
229
230 ret = __compare_inode_defrag(&tmp, entry);
231 if (ret < 0)
232 p = parent->rb_left;
233 else if (ret > 0)
234 p = parent->rb_right;
235 else
236 goto out;
237 }
238
239 if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
240 parent = rb_next(parent);
241 if (parent)
242 entry = rb_entry(parent, struct inode_defrag, rb_node);
243 else
244 entry = NULL;
245 }
246out:
247 if (entry)
248 rb_erase(parent, &fs_info->defrag_inodes);
249 spin_unlock(&fs_info->defrag_inodes_lock);
250 return entry;
251}
252
253void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
254{
255 struct inode_defrag *defrag;
256 struct rb_node *node;
257
258 spin_lock(&fs_info->defrag_inodes_lock);
259 node = rb_first(&fs_info->defrag_inodes);
260 while (node) {
261 rb_erase(node, &fs_info->defrag_inodes);
262 defrag = rb_entry(node, struct inode_defrag, rb_node);
263 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
264
265 cond_resched_lock(&fs_info->defrag_inodes_lock);
266
267 node = rb_first(&fs_info->defrag_inodes);
268 }
269 spin_unlock(&fs_info->defrag_inodes_lock);
270}
271
272#define BTRFS_DEFRAG_BATCH 1024
273
274static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
275 struct inode_defrag *defrag)
276{
277 struct btrfs_root *inode_root;
278 struct inode *inode;
279 struct btrfs_ioctl_defrag_range_args range;
280 int num_defrag;
281 int ret;
282
283 /* get the inode */
284 inode_root = btrfs_get_fs_root(fs_info, defrag->root, true);
285 if (IS_ERR(inode_root)) {
286 ret = PTR_ERR(inode_root);
287 goto cleanup;
288 }
289
290 inode = btrfs_iget(fs_info->sb, defrag->ino, inode_root);
291 btrfs_put_root(inode_root);
292 if (IS_ERR(inode)) {
293 ret = PTR_ERR(inode);
294 goto cleanup;
295 }
296
297 /* do a chunk of defrag */
298 clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
299 memset(&range, 0, sizeof(range));
300 range.len = (u64)-1;
301 range.start = defrag->last_offset;
302
303 sb_start_write(fs_info->sb);
304 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
305 BTRFS_DEFRAG_BATCH);
306 sb_end_write(fs_info->sb);
307 /*
308 * if we filled the whole defrag batch, there
309 * must be more work to do. Queue this defrag
310 * again
311 */
312 if (num_defrag == BTRFS_DEFRAG_BATCH) {
313 defrag->last_offset = range.start;
314 btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
315 } else if (defrag->last_offset && !defrag->cycled) {
316 /*
317 * we didn't fill our defrag batch, but
318 * we didn't start at zero. Make sure we loop
319 * around to the start of the file.
320 */
321 defrag->last_offset = 0;
322 defrag->cycled = 1;
323 btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
324 } else {
325 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
326 }
327
328 iput(inode);
329 return 0;
330cleanup:
331 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
332 return ret;
333}
334
335/*
336 * run through the list of inodes in the FS that need
337 * defragging
338 */
339int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
340{
341 struct inode_defrag *defrag;
342 u64 first_ino = 0;
343 u64 root_objectid = 0;
344
345 atomic_inc(&fs_info->defrag_running);
346 while (1) {
347 /* Pause the auto defragger. */
348 if (test_bit(BTRFS_FS_STATE_REMOUNTING,
349 &fs_info->fs_state))
350 break;
351
352 if (!__need_auto_defrag(fs_info))
353 break;
354
355 /* find an inode to defrag */
356 defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
357 first_ino);
358 if (!defrag) {
359 if (root_objectid || first_ino) {
360 root_objectid = 0;
361 first_ino = 0;
362 continue;
363 } else {
364 break;
365 }
366 }
367
368 first_ino = defrag->ino + 1;
369 root_objectid = defrag->root;
370
371 __btrfs_run_defrag_inode(fs_info, defrag);
372 }
373 atomic_dec(&fs_info->defrag_running);
374
375 /*
376 * during unmount, we use the transaction_wait queue to
377 * wait for the defragger to stop
378 */
379 wake_up(&fs_info->transaction_wait);
380 return 0;
381}
382
383/* simple helper to fault in pages and copy. This should go away
384 * and be replaced with calls into generic code.
385 */
386static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
387 struct page **prepared_pages,
388 struct iov_iter *i)
389{
390 size_t copied = 0;
391 size_t total_copied = 0;
392 int pg = 0;
393 int offset = offset_in_page(pos);
394
395 while (write_bytes > 0) {
396 size_t count = min_t(size_t,
397 PAGE_SIZE - offset, write_bytes);
398 struct page *page = prepared_pages[pg];
399 /*
400 * Copy data from userspace to the current page
401 */
402 copied = copy_page_from_iter_atomic(page, offset, count, i);
403
404 /* Flush processor's dcache for this page */
405 flush_dcache_page(page);
406
407 /*
408 * if we get a partial write, we can end up with
409 * partially up to date pages. These add
410 * a lot of complexity, so make sure they don't
411 * happen by forcing this copy to be retried.
412 *
413 * The rest of the btrfs_file_write code will fall
414 * back to page at a time copies after we return 0.
415 */
416 if (unlikely(copied < count)) {
417 if (!PageUptodate(page)) {
418 iov_iter_revert(i, copied);
419 copied = 0;
420 }
421 if (!copied)
422 break;
423 }
424
425 write_bytes -= copied;
426 total_copied += copied;
427 offset += copied;
428 if (offset == PAGE_SIZE) {
429 pg++;
430 offset = 0;
431 }
432 }
433 return total_copied;
434}
435
436/*
437 * unlocks pages after btrfs_file_write is done with them
438 */
439static void btrfs_drop_pages(struct page **pages, size_t num_pages)
440{
441 size_t i;
442 for (i = 0; i < num_pages; i++) {
443 /* page checked is some magic around finding pages that
444 * have been modified without going through btrfs_set_page_dirty
445 * clear it here. There should be no need to mark the pages
446 * accessed as prepare_pages should have marked them accessed
447 * in prepare_pages via find_or_create_page()
448 */
449 ClearPageChecked(pages[i]);
450 unlock_page(pages[i]);
451 put_page(pages[i]);
452 }
453}
454
455/*
456 * After btrfs_copy_from_user(), update the following things for delalloc:
457 * - Mark newly dirtied pages as DELALLOC in the io tree.
458 * Used to advise which range is to be written back.
459 * - Mark modified pages as Uptodate/Dirty and not needing COW fixup
460 * - Update inode size for past EOF write
461 */
462int btrfs_dirty_pages(struct btrfs_inode *inode, struct page **pages,
463 size_t num_pages, loff_t pos, size_t write_bytes,
464 struct extent_state **cached, bool noreserve)
465{
466 struct btrfs_fs_info *fs_info = inode->root->fs_info;
467 int err = 0;
468 int i;
469 u64 num_bytes;
470 u64 start_pos;
471 u64 end_of_last_block;
472 u64 end_pos = pos + write_bytes;
473 loff_t isize = i_size_read(&inode->vfs_inode);
474 unsigned int extra_bits = 0;
475
476 if (write_bytes == 0)
477 return 0;
478
479 if (noreserve)
480 extra_bits |= EXTENT_NORESERVE;
481
482 start_pos = round_down(pos, fs_info->sectorsize);
483 num_bytes = round_up(write_bytes + pos - start_pos,
484 fs_info->sectorsize);
485 ASSERT(num_bytes <= U32_MAX);
486
487 end_of_last_block = start_pos + num_bytes - 1;
488
489 /*
490 * The pages may have already been dirty, clear out old accounting so
491 * we can set things up properly
492 */
493 clear_extent_bit(&inode->io_tree, start_pos, end_of_last_block,
494 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
495 0, 0, cached);
496
497 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
498 extra_bits, cached);
499 if (err)
500 return err;
501
502 for (i = 0; i < num_pages; i++) {
503 struct page *p = pages[i];
504
505 btrfs_page_clamp_set_uptodate(fs_info, p, start_pos, num_bytes);
506 ClearPageChecked(p);
507 btrfs_page_clamp_set_dirty(fs_info, p, start_pos, num_bytes);
508 }
509
510 /*
511 * we've only changed i_size in ram, and we haven't updated
512 * the disk i_size. There is no need to log the inode
513 * at this time.
514 */
515 if (end_pos > isize)
516 i_size_write(&inode->vfs_inode, end_pos);
517 return 0;
518}
519
520/*
521 * this drops all the extents in the cache that intersect the range
522 * [start, end]. Existing extents are split as required.
523 */
524void btrfs_drop_extent_cache(struct btrfs_inode *inode, u64 start, u64 end,
525 int skip_pinned)
526{
527 struct extent_map *em;
528 struct extent_map *split = NULL;
529 struct extent_map *split2 = NULL;
530 struct extent_map_tree *em_tree = &inode->extent_tree;
531 u64 len = end - start + 1;
532 u64 gen;
533 int ret;
534 int testend = 1;
535 unsigned long flags;
536 int compressed = 0;
537 bool modified;
538
539 WARN_ON(end < start);
540 if (end == (u64)-1) {
541 len = (u64)-1;
542 testend = 0;
543 }
544 while (1) {
545 int no_splits = 0;
546
547 modified = false;
548 if (!split)
549 split = alloc_extent_map();
550 if (!split2)
551 split2 = alloc_extent_map();
552 if (!split || !split2)
553 no_splits = 1;
554
555 write_lock(&em_tree->lock);
556 em = lookup_extent_mapping(em_tree, start, len);
557 if (!em) {
558 write_unlock(&em_tree->lock);
559 break;
560 }
561 flags = em->flags;
562 gen = em->generation;
563 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
564 if (testend && em->start + em->len >= start + len) {
565 free_extent_map(em);
566 write_unlock(&em_tree->lock);
567 break;
568 }
569 start = em->start + em->len;
570 if (testend)
571 len = start + len - (em->start + em->len);
572 free_extent_map(em);
573 write_unlock(&em_tree->lock);
574 continue;
575 }
576 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
577 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
578 clear_bit(EXTENT_FLAG_LOGGING, &flags);
579 modified = !list_empty(&em->list);
580 if (no_splits)
581 goto next;
582
583 if (em->start < start) {
584 split->start = em->start;
585 split->len = start - em->start;
586
587 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
588 split->orig_start = em->orig_start;
589 split->block_start = em->block_start;
590
591 if (compressed)
592 split->block_len = em->block_len;
593 else
594 split->block_len = split->len;
595 split->orig_block_len = max(split->block_len,
596 em->orig_block_len);
597 split->ram_bytes = em->ram_bytes;
598 } else {
599 split->orig_start = split->start;
600 split->block_len = 0;
601 split->block_start = em->block_start;
602 split->orig_block_len = 0;
603 split->ram_bytes = split->len;
604 }
605
606 split->generation = gen;
607 split->flags = flags;
608 split->compress_type = em->compress_type;
609 replace_extent_mapping(em_tree, em, split, modified);
610 free_extent_map(split);
611 split = split2;
612 split2 = NULL;
613 }
614 if (testend && em->start + em->len > start + len) {
615 u64 diff = start + len - em->start;
616
617 split->start = start + len;
618 split->len = em->start + em->len - (start + len);
619 split->flags = flags;
620 split->compress_type = em->compress_type;
621 split->generation = gen;
622
623 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
624 split->orig_block_len = max(em->block_len,
625 em->orig_block_len);
626
627 split->ram_bytes = em->ram_bytes;
628 if (compressed) {
629 split->block_len = em->block_len;
630 split->block_start = em->block_start;
631 split->orig_start = em->orig_start;
632 } else {
633 split->block_len = split->len;
634 split->block_start = em->block_start
635 + diff;
636 split->orig_start = em->orig_start;
637 }
638 } else {
639 split->ram_bytes = split->len;
640 split->orig_start = split->start;
641 split->block_len = 0;
642 split->block_start = em->block_start;
643 split->orig_block_len = 0;
644 }
645
646 if (extent_map_in_tree(em)) {
647 replace_extent_mapping(em_tree, em, split,
648 modified);
649 } else {
650 ret = add_extent_mapping(em_tree, split,
651 modified);
652 ASSERT(ret == 0); /* Logic error */
653 }
654 free_extent_map(split);
655 split = NULL;
656 }
657next:
658 if (extent_map_in_tree(em))
659 remove_extent_mapping(em_tree, em);
660 write_unlock(&em_tree->lock);
661
662 /* once for us */
663 free_extent_map(em);
664 /* once for the tree*/
665 free_extent_map(em);
666 }
667 if (split)
668 free_extent_map(split);
669 if (split2)
670 free_extent_map(split2);
671}
672
673/*
674 * this is very complex, but the basic idea is to drop all extents
675 * in the range start - end. hint_block is filled in with a block number
676 * that would be a good hint to the block allocator for this file.
677 *
678 * If an extent intersects the range but is not entirely inside the range
679 * it is either truncated or split. Anything entirely inside the range
680 * is deleted from the tree.
681 *
682 * Note: the VFS' inode number of bytes is not updated, it's up to the caller
683 * to deal with that. We set the field 'bytes_found' of the arguments structure
684 * with the number of allocated bytes found in the target range, so that the
685 * caller can update the inode's number of bytes in an atomic way when
686 * replacing extents in a range to avoid races with stat(2).
687 */
688int btrfs_drop_extents(struct btrfs_trans_handle *trans,
689 struct btrfs_root *root, struct btrfs_inode *inode,
690 struct btrfs_drop_extents_args *args)
691{
692 struct btrfs_fs_info *fs_info = root->fs_info;
693 struct extent_buffer *leaf;
694 struct btrfs_file_extent_item *fi;
695 struct btrfs_ref ref = { 0 };
696 struct btrfs_key key;
697 struct btrfs_key new_key;
698 u64 ino = btrfs_ino(inode);
699 u64 search_start = args->start;
700 u64 disk_bytenr = 0;
701 u64 num_bytes = 0;
702 u64 extent_offset = 0;
703 u64 extent_end = 0;
704 u64 last_end = args->start;
705 int del_nr = 0;
706 int del_slot = 0;
707 int extent_type;
708 int recow;
709 int ret;
710 int modify_tree = -1;
711 int update_refs;
712 int found = 0;
713 int leafs_visited = 0;
714 struct btrfs_path *path = args->path;
715
716 args->bytes_found = 0;
717 args->extent_inserted = false;
718
719 /* Must always have a path if ->replace_extent is true */
720 ASSERT(!(args->replace_extent && !args->path));
721
722 if (!path) {
723 path = btrfs_alloc_path();
724 if (!path) {
725 ret = -ENOMEM;
726 goto out;
727 }
728 }
729
730 if (args->drop_cache)
731 btrfs_drop_extent_cache(inode, args->start, args->end - 1, 0);
732
733 if (args->start >= inode->disk_i_size && !args->replace_extent)
734 modify_tree = 0;
735
736 update_refs = (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID);
737 while (1) {
738 recow = 0;
739 ret = btrfs_lookup_file_extent(trans, root, path, ino,
740 search_start, modify_tree);
741 if (ret < 0)
742 break;
743 if (ret > 0 && path->slots[0] > 0 && search_start == args->start) {
744 leaf = path->nodes[0];
745 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
746 if (key.objectid == ino &&
747 key.type == BTRFS_EXTENT_DATA_KEY)
748 path->slots[0]--;
749 }
750 ret = 0;
751 leafs_visited++;
752next_slot:
753 leaf = path->nodes[0];
754 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
755 BUG_ON(del_nr > 0);
756 ret = btrfs_next_leaf(root, path);
757 if (ret < 0)
758 break;
759 if (ret > 0) {
760 ret = 0;
761 break;
762 }
763 leafs_visited++;
764 leaf = path->nodes[0];
765 recow = 1;
766 }
767
768 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
769
770 if (key.objectid > ino)
771 break;
772 if (WARN_ON_ONCE(key.objectid < ino) ||
773 key.type < BTRFS_EXTENT_DATA_KEY) {
774 ASSERT(del_nr == 0);
775 path->slots[0]++;
776 goto next_slot;
777 }
778 if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= args->end)
779 break;
780
781 fi = btrfs_item_ptr(leaf, path->slots[0],
782 struct btrfs_file_extent_item);
783 extent_type = btrfs_file_extent_type(leaf, fi);
784
785 if (extent_type == BTRFS_FILE_EXTENT_REG ||
786 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
787 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
788 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
789 extent_offset = btrfs_file_extent_offset(leaf, fi);
790 extent_end = key.offset +
791 btrfs_file_extent_num_bytes(leaf, fi);
792 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
793 extent_end = key.offset +
794 btrfs_file_extent_ram_bytes(leaf, fi);
795 } else {
796 /* can't happen */
797 BUG();
798 }
799
800 /*
801 * Don't skip extent items representing 0 byte lengths. They
802 * used to be created (bug) if while punching holes we hit
803 * -ENOSPC condition. So if we find one here, just ensure we
804 * delete it, otherwise we would insert a new file extent item
805 * with the same key (offset) as that 0 bytes length file
806 * extent item in the call to setup_items_for_insert() later
807 * in this function.
808 */
809 if (extent_end == key.offset && extent_end >= search_start) {
810 last_end = extent_end;
811 goto delete_extent_item;
812 }
813
814 if (extent_end <= search_start) {
815 path->slots[0]++;
816 goto next_slot;
817 }
818
819 found = 1;
820 search_start = max(key.offset, args->start);
821 if (recow || !modify_tree) {
822 modify_tree = -1;
823 btrfs_release_path(path);
824 continue;
825 }
826
827 /*
828 * | - range to drop - |
829 * | -------- extent -------- |
830 */
831 if (args->start > key.offset && args->end < extent_end) {
832 BUG_ON(del_nr > 0);
833 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
834 ret = -EOPNOTSUPP;
835 break;
836 }
837
838 memcpy(&new_key, &key, sizeof(new_key));
839 new_key.offset = args->start;
840 ret = btrfs_duplicate_item(trans, root, path,
841 &new_key);
842 if (ret == -EAGAIN) {
843 btrfs_release_path(path);
844 continue;
845 }
846 if (ret < 0)
847 break;
848
849 leaf = path->nodes[0];
850 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
851 struct btrfs_file_extent_item);
852 btrfs_set_file_extent_num_bytes(leaf, fi,
853 args->start - key.offset);
854
855 fi = btrfs_item_ptr(leaf, path->slots[0],
856 struct btrfs_file_extent_item);
857
858 extent_offset += args->start - key.offset;
859 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
860 btrfs_set_file_extent_num_bytes(leaf, fi,
861 extent_end - args->start);
862 btrfs_mark_buffer_dirty(leaf);
863
864 if (update_refs && disk_bytenr > 0) {
865 btrfs_init_generic_ref(&ref,
866 BTRFS_ADD_DELAYED_REF,
867 disk_bytenr, num_bytes, 0);
868 btrfs_init_data_ref(&ref,
869 root->root_key.objectid,
870 new_key.objectid,
871 args->start - extent_offset);
872 ret = btrfs_inc_extent_ref(trans, &ref);
873 BUG_ON(ret); /* -ENOMEM */
874 }
875 key.offset = args->start;
876 }
877 /*
878 * From here on out we will have actually dropped something, so
879 * last_end can be updated.
880 */
881 last_end = extent_end;
882
883 /*
884 * | ---- range to drop ----- |
885 * | -------- extent -------- |
886 */
887 if (args->start <= key.offset && args->end < extent_end) {
888 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
889 ret = -EOPNOTSUPP;
890 break;
891 }
892
893 memcpy(&new_key, &key, sizeof(new_key));
894 new_key.offset = args->end;
895 btrfs_set_item_key_safe(fs_info, path, &new_key);
896
897 extent_offset += args->end - key.offset;
898 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
899 btrfs_set_file_extent_num_bytes(leaf, fi,
900 extent_end - args->end);
901 btrfs_mark_buffer_dirty(leaf);
902 if (update_refs && disk_bytenr > 0)
903 args->bytes_found += args->end - key.offset;
904 break;
905 }
906
907 search_start = extent_end;
908 /*
909 * | ---- range to drop ----- |
910 * | -------- extent -------- |
911 */
912 if (args->start > key.offset && args->end >= extent_end) {
913 BUG_ON(del_nr > 0);
914 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
915 ret = -EOPNOTSUPP;
916 break;
917 }
918
919 btrfs_set_file_extent_num_bytes(leaf, fi,
920 args->start - key.offset);
921 btrfs_mark_buffer_dirty(leaf);
922 if (update_refs && disk_bytenr > 0)
923 args->bytes_found += extent_end - args->start;
924 if (args->end == extent_end)
925 break;
926
927 path->slots[0]++;
928 goto next_slot;
929 }
930
931 /*
932 * | ---- range to drop ----- |
933 * | ------ extent ------ |
934 */
935 if (args->start <= key.offset && args->end >= extent_end) {
936delete_extent_item:
937 if (del_nr == 0) {
938 del_slot = path->slots[0];
939 del_nr = 1;
940 } else {
941 BUG_ON(del_slot + del_nr != path->slots[0]);
942 del_nr++;
943 }
944
945 if (update_refs &&
946 extent_type == BTRFS_FILE_EXTENT_INLINE) {
947 args->bytes_found += extent_end - key.offset;
948 extent_end = ALIGN(extent_end,
949 fs_info->sectorsize);
950 } else if (update_refs && disk_bytenr > 0) {
951 btrfs_init_generic_ref(&ref,
952 BTRFS_DROP_DELAYED_REF,
953 disk_bytenr, num_bytes, 0);
954 btrfs_init_data_ref(&ref,
955 root->root_key.objectid,
956 key.objectid,
957 key.offset - extent_offset);
958 ret = btrfs_free_extent(trans, &ref);
959 BUG_ON(ret); /* -ENOMEM */
960 args->bytes_found += extent_end - key.offset;
961 }
962
963 if (args->end == extent_end)
964 break;
965
966 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
967 path->slots[0]++;
968 goto next_slot;
969 }
970
971 ret = btrfs_del_items(trans, root, path, del_slot,
972 del_nr);
973 if (ret) {
974 btrfs_abort_transaction(trans, ret);
975 break;
976 }
977
978 del_nr = 0;
979 del_slot = 0;
980
981 btrfs_release_path(path);
982 continue;
983 }
984
985 BUG();
986 }
987
988 if (!ret && del_nr > 0) {
989 /*
990 * Set path->slots[0] to first slot, so that after the delete
991 * if items are move off from our leaf to its immediate left or
992 * right neighbor leafs, we end up with a correct and adjusted
993 * path->slots[0] for our insertion (if args->replace_extent).
994 */
995 path->slots[0] = del_slot;
996 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
997 if (ret)
998 btrfs_abort_transaction(trans, ret);
999 }
1000
1001 leaf = path->nodes[0];
1002 /*
1003 * If btrfs_del_items() was called, it might have deleted a leaf, in
1004 * which case it unlocked our path, so check path->locks[0] matches a
1005 * write lock.
1006 */
1007 if (!ret && args->replace_extent && leafs_visited == 1 &&
1008 path->locks[0] == BTRFS_WRITE_LOCK &&
1009 btrfs_leaf_free_space(leaf) >=
1010 sizeof(struct btrfs_item) + args->extent_item_size) {
1011
1012 key.objectid = ino;
1013 key.type = BTRFS_EXTENT_DATA_KEY;
1014 key.offset = args->start;
1015 if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
1016 struct btrfs_key slot_key;
1017
1018 btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
1019 if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
1020 path->slots[0]++;
1021 }
1022 setup_items_for_insert(root, path, &key,
1023 &args->extent_item_size, 1);
1024 args->extent_inserted = true;
1025 }
1026
1027 if (!args->path)
1028 btrfs_free_path(path);
1029 else if (!args->extent_inserted)
1030 btrfs_release_path(path);
1031out:
1032 args->drop_end = found ? min(args->end, last_end) : args->end;
1033
1034 return ret;
1035}
1036
1037static int extent_mergeable(struct extent_buffer *leaf, int slot,
1038 u64 objectid, u64 bytenr, u64 orig_offset,
1039 u64 *start, u64 *end)
1040{
1041 struct btrfs_file_extent_item *fi;
1042 struct btrfs_key key;
1043 u64 extent_end;
1044
1045 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
1046 return 0;
1047
1048 btrfs_item_key_to_cpu(leaf, &key, slot);
1049 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
1050 return 0;
1051
1052 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1053 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
1054 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
1055 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
1056 btrfs_file_extent_compression(leaf, fi) ||
1057 btrfs_file_extent_encryption(leaf, fi) ||
1058 btrfs_file_extent_other_encoding(leaf, fi))
1059 return 0;
1060
1061 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1062 if ((*start && *start != key.offset) || (*end && *end != extent_end))
1063 return 0;
1064
1065 *start = key.offset;
1066 *end = extent_end;
1067 return 1;
1068}
1069
1070/*
1071 * Mark extent in the range start - end as written.
1072 *
1073 * This changes extent type from 'pre-allocated' to 'regular'. If only
1074 * part of extent is marked as written, the extent will be split into
1075 * two or three.
1076 */
1077int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
1078 struct btrfs_inode *inode, u64 start, u64 end)
1079{
1080 struct btrfs_fs_info *fs_info = trans->fs_info;
1081 struct btrfs_root *root = inode->root;
1082 struct extent_buffer *leaf;
1083 struct btrfs_path *path;
1084 struct btrfs_file_extent_item *fi;
1085 struct btrfs_ref ref = { 0 };
1086 struct btrfs_key key;
1087 struct btrfs_key new_key;
1088 u64 bytenr;
1089 u64 num_bytes;
1090 u64 extent_end;
1091 u64 orig_offset;
1092 u64 other_start;
1093 u64 other_end;
1094 u64 split;
1095 int del_nr = 0;
1096 int del_slot = 0;
1097 int recow;
1098 int ret = 0;
1099 u64 ino = btrfs_ino(inode);
1100
1101 path = btrfs_alloc_path();
1102 if (!path)
1103 return -ENOMEM;
1104again:
1105 recow = 0;
1106 split = start;
1107 key.objectid = ino;
1108 key.type = BTRFS_EXTENT_DATA_KEY;
1109 key.offset = split;
1110
1111 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1112 if (ret < 0)
1113 goto out;
1114 if (ret > 0 && path->slots[0] > 0)
1115 path->slots[0]--;
1116
1117 leaf = path->nodes[0];
1118 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1119 if (key.objectid != ino ||
1120 key.type != BTRFS_EXTENT_DATA_KEY) {
1121 ret = -EINVAL;
1122 btrfs_abort_transaction(trans, ret);
1123 goto out;
1124 }
1125 fi = btrfs_item_ptr(leaf, path->slots[0],
1126 struct btrfs_file_extent_item);
1127 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
1128 ret = -EINVAL;
1129 btrfs_abort_transaction(trans, ret);
1130 goto out;
1131 }
1132 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1133 if (key.offset > start || extent_end < end) {
1134 ret = -EINVAL;
1135 btrfs_abort_transaction(trans, ret);
1136 goto out;
1137 }
1138
1139 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1140 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1141 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1142 memcpy(&new_key, &key, sizeof(new_key));
1143
1144 if (start == key.offset && end < extent_end) {
1145 other_start = 0;
1146 other_end = start;
1147 if (extent_mergeable(leaf, path->slots[0] - 1,
1148 ino, bytenr, orig_offset,
1149 &other_start, &other_end)) {
1150 new_key.offset = end;
1151 btrfs_set_item_key_safe(fs_info, path, &new_key);
1152 fi = btrfs_item_ptr(leaf, path->slots[0],
1153 struct btrfs_file_extent_item);
1154 btrfs_set_file_extent_generation(leaf, fi,
1155 trans->transid);
1156 btrfs_set_file_extent_num_bytes(leaf, fi,
1157 extent_end - end);
1158 btrfs_set_file_extent_offset(leaf, fi,
1159 end - orig_offset);
1160 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1161 struct btrfs_file_extent_item);
1162 btrfs_set_file_extent_generation(leaf, fi,
1163 trans->transid);
1164 btrfs_set_file_extent_num_bytes(leaf, fi,
1165 end - other_start);
1166 btrfs_mark_buffer_dirty(leaf);
1167 goto out;
1168 }
1169 }
1170
1171 if (start > key.offset && end == extent_end) {
1172 other_start = end;
1173 other_end = 0;
1174 if (extent_mergeable(leaf, path->slots[0] + 1,
1175 ino, bytenr, orig_offset,
1176 &other_start, &other_end)) {
1177 fi = btrfs_item_ptr(leaf, path->slots[0],
1178 struct btrfs_file_extent_item);
1179 btrfs_set_file_extent_num_bytes(leaf, fi,
1180 start - key.offset);
1181 btrfs_set_file_extent_generation(leaf, fi,
1182 trans->transid);
1183 path->slots[0]++;
1184 new_key.offset = start;
1185 btrfs_set_item_key_safe(fs_info, path, &new_key);
1186
1187 fi = btrfs_item_ptr(leaf, path->slots[0],
1188 struct btrfs_file_extent_item);
1189 btrfs_set_file_extent_generation(leaf, fi,
1190 trans->transid);
1191 btrfs_set_file_extent_num_bytes(leaf, fi,
1192 other_end - start);
1193 btrfs_set_file_extent_offset(leaf, fi,
1194 start - orig_offset);
1195 btrfs_mark_buffer_dirty(leaf);
1196 goto out;
1197 }
1198 }
1199
1200 while (start > key.offset || end < extent_end) {
1201 if (key.offset == start)
1202 split = end;
1203
1204 new_key.offset = split;
1205 ret = btrfs_duplicate_item(trans, root, path, &new_key);
1206 if (ret == -EAGAIN) {
1207 btrfs_release_path(path);
1208 goto again;
1209 }
1210 if (ret < 0) {
1211 btrfs_abort_transaction(trans, ret);
1212 goto out;
1213 }
1214
1215 leaf = path->nodes[0];
1216 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1217 struct btrfs_file_extent_item);
1218 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1219 btrfs_set_file_extent_num_bytes(leaf, fi,
1220 split - key.offset);
1221
1222 fi = btrfs_item_ptr(leaf, path->slots[0],
1223 struct btrfs_file_extent_item);
1224
1225 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1226 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1227 btrfs_set_file_extent_num_bytes(leaf, fi,
1228 extent_end - split);
1229 btrfs_mark_buffer_dirty(leaf);
1230
1231 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, bytenr,
1232 num_bytes, 0);
1233 btrfs_init_data_ref(&ref, root->root_key.objectid, ino,
1234 orig_offset);
1235 ret = btrfs_inc_extent_ref(trans, &ref);
1236 if (ret) {
1237 btrfs_abort_transaction(trans, ret);
1238 goto out;
1239 }
1240
1241 if (split == start) {
1242 key.offset = start;
1243 } else {
1244 if (start != key.offset) {
1245 ret = -EINVAL;
1246 btrfs_abort_transaction(trans, ret);
1247 goto out;
1248 }
1249 path->slots[0]--;
1250 extent_end = end;
1251 }
1252 recow = 1;
1253 }
1254
1255 other_start = end;
1256 other_end = 0;
1257 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1258 num_bytes, 0);
1259 btrfs_init_data_ref(&ref, root->root_key.objectid, ino, orig_offset);
1260 if (extent_mergeable(leaf, path->slots[0] + 1,
1261 ino, bytenr, orig_offset,
1262 &other_start, &other_end)) {
1263 if (recow) {
1264 btrfs_release_path(path);
1265 goto again;
1266 }
1267 extent_end = other_end;
1268 del_slot = path->slots[0] + 1;
1269 del_nr++;
1270 ret = btrfs_free_extent(trans, &ref);
1271 if (ret) {
1272 btrfs_abort_transaction(trans, ret);
1273 goto out;
1274 }
1275 }
1276 other_start = 0;
1277 other_end = start;
1278 if (extent_mergeable(leaf, path->slots[0] - 1,
1279 ino, bytenr, orig_offset,
1280 &other_start, &other_end)) {
1281 if (recow) {
1282 btrfs_release_path(path);
1283 goto again;
1284 }
1285 key.offset = other_start;
1286 del_slot = path->slots[0];
1287 del_nr++;
1288 ret = btrfs_free_extent(trans, &ref);
1289 if (ret) {
1290 btrfs_abort_transaction(trans, ret);
1291 goto out;
1292 }
1293 }
1294 if (del_nr == 0) {
1295 fi = btrfs_item_ptr(leaf, path->slots[0],
1296 struct btrfs_file_extent_item);
1297 btrfs_set_file_extent_type(leaf, fi,
1298 BTRFS_FILE_EXTENT_REG);
1299 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1300 btrfs_mark_buffer_dirty(leaf);
1301 } else {
1302 fi = btrfs_item_ptr(leaf, del_slot - 1,
1303 struct btrfs_file_extent_item);
1304 btrfs_set_file_extent_type(leaf, fi,
1305 BTRFS_FILE_EXTENT_REG);
1306 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1307 btrfs_set_file_extent_num_bytes(leaf, fi,
1308 extent_end - key.offset);
1309 btrfs_mark_buffer_dirty(leaf);
1310
1311 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1312 if (ret < 0) {
1313 btrfs_abort_transaction(trans, ret);
1314 goto out;
1315 }
1316 }
1317out:
1318 btrfs_free_path(path);
1319 return ret;
1320}
1321
1322/*
1323 * on error we return an unlocked page and the error value
1324 * on success we return a locked page and 0
1325 */
1326static int prepare_uptodate_page(struct inode *inode,
1327 struct page *page, u64 pos,
1328 bool force_uptodate)
1329{
1330 int ret = 0;
1331
1332 if (((pos & (PAGE_SIZE - 1)) || force_uptodate) &&
1333 !PageUptodate(page)) {
1334 ret = btrfs_readpage(NULL, page);
1335 if (ret)
1336 return ret;
1337 lock_page(page);
1338 if (!PageUptodate(page)) {
1339 unlock_page(page);
1340 return -EIO;
1341 }
1342 if (page->mapping != inode->i_mapping) {
1343 unlock_page(page);
1344 return -EAGAIN;
1345 }
1346 }
1347 return 0;
1348}
1349
1350/*
1351 * this just gets pages into the page cache and locks them down.
1352 */
1353static noinline int prepare_pages(struct inode *inode, struct page **pages,
1354 size_t num_pages, loff_t pos,
1355 size_t write_bytes, bool force_uptodate)
1356{
1357 int i;
1358 unsigned long index = pos >> PAGE_SHIFT;
1359 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1360 int err = 0;
1361 int faili;
1362
1363 for (i = 0; i < num_pages; i++) {
1364again:
1365 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1366 mask | __GFP_WRITE);
1367 if (!pages[i]) {
1368 faili = i - 1;
1369 err = -ENOMEM;
1370 goto fail;
1371 }
1372
1373 err = set_page_extent_mapped(pages[i]);
1374 if (err < 0) {
1375 faili = i;
1376 goto fail;
1377 }
1378
1379 if (i == 0)
1380 err = prepare_uptodate_page(inode, pages[i], pos,
1381 force_uptodate);
1382 if (!err && i == num_pages - 1)
1383 err = prepare_uptodate_page(inode, pages[i],
1384 pos + write_bytes, false);
1385 if (err) {
1386 put_page(pages[i]);
1387 if (err == -EAGAIN) {
1388 err = 0;
1389 goto again;
1390 }
1391 faili = i - 1;
1392 goto fail;
1393 }
1394 wait_on_page_writeback(pages[i]);
1395 }
1396
1397 return 0;
1398fail:
1399 while (faili >= 0) {
1400 unlock_page(pages[faili]);
1401 put_page(pages[faili]);
1402 faili--;
1403 }
1404 return err;
1405
1406}
1407
1408/*
1409 * This function locks the extent and properly waits for data=ordered extents
1410 * to finish before allowing the pages to be modified if need.
1411 *
1412 * The return value:
1413 * 1 - the extent is locked
1414 * 0 - the extent is not locked, and everything is OK
1415 * -EAGAIN - need re-prepare the pages
1416 * the other < 0 number - Something wrong happens
1417 */
1418static noinline int
1419lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
1420 size_t num_pages, loff_t pos,
1421 size_t write_bytes,
1422 u64 *lockstart, u64 *lockend,
1423 struct extent_state **cached_state)
1424{
1425 struct btrfs_fs_info *fs_info = inode->root->fs_info;
1426 u64 start_pos;
1427 u64 last_pos;
1428 int i;
1429 int ret = 0;
1430
1431 start_pos = round_down(pos, fs_info->sectorsize);
1432 last_pos = round_up(pos + write_bytes, fs_info->sectorsize) - 1;
1433
1434 if (start_pos < inode->vfs_inode.i_size) {
1435 struct btrfs_ordered_extent *ordered;
1436
1437 lock_extent_bits(&inode->io_tree, start_pos, last_pos,
1438 cached_state);
1439 ordered = btrfs_lookup_ordered_range(inode, start_pos,
1440 last_pos - start_pos + 1);
1441 if (ordered &&
1442 ordered->file_offset + ordered->num_bytes > start_pos &&
1443 ordered->file_offset <= last_pos) {
1444 unlock_extent_cached(&inode->io_tree, start_pos,
1445 last_pos, cached_state);
1446 for (i = 0; i < num_pages; i++) {
1447 unlock_page(pages[i]);
1448 put_page(pages[i]);
1449 }
1450 btrfs_start_ordered_extent(ordered, 1);
1451 btrfs_put_ordered_extent(ordered);
1452 return -EAGAIN;
1453 }
1454 if (ordered)
1455 btrfs_put_ordered_extent(ordered);
1456
1457 *lockstart = start_pos;
1458 *lockend = last_pos;
1459 ret = 1;
1460 }
1461
1462 /*
1463 * We should be called after prepare_pages() which should have locked
1464 * all pages in the range.
1465 */
1466 for (i = 0; i < num_pages; i++)
1467 WARN_ON(!PageLocked(pages[i]));
1468
1469 return ret;
1470}
1471
1472static int check_can_nocow(struct btrfs_inode *inode, loff_t pos,
1473 size_t *write_bytes, bool nowait)
1474{
1475 struct btrfs_fs_info *fs_info = inode->root->fs_info;
1476 struct btrfs_root *root = inode->root;
1477 u64 lockstart, lockend;
1478 u64 num_bytes;
1479 int ret;
1480
1481 if (!(inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)))
1482 return 0;
1483
1484 if (!nowait && !btrfs_drew_try_write_lock(&root->snapshot_lock))
1485 return -EAGAIN;
1486
1487 lockstart = round_down(pos, fs_info->sectorsize);
1488 lockend = round_up(pos + *write_bytes,
1489 fs_info->sectorsize) - 1;
1490 num_bytes = lockend - lockstart + 1;
1491
1492 if (nowait) {
1493 struct btrfs_ordered_extent *ordered;
1494
1495 if (!try_lock_extent(&inode->io_tree, lockstart, lockend))
1496 return -EAGAIN;
1497
1498 ordered = btrfs_lookup_ordered_range(inode, lockstart,
1499 num_bytes);
1500 if (ordered) {
1501 btrfs_put_ordered_extent(ordered);
1502 ret = -EAGAIN;
1503 goto out_unlock;
1504 }
1505 } else {
1506 btrfs_lock_and_flush_ordered_range(inode, lockstart,
1507 lockend, NULL);
1508 }
1509
1510 ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
1511 NULL, NULL, NULL, false);
1512 if (ret <= 0) {
1513 ret = 0;
1514 if (!nowait)
1515 btrfs_drew_write_unlock(&root->snapshot_lock);
1516 } else {
1517 *write_bytes = min_t(size_t, *write_bytes ,
1518 num_bytes - pos + lockstart);
1519 }
1520out_unlock:
1521 unlock_extent(&inode->io_tree, lockstart, lockend);
1522
1523 return ret;
1524}
1525
1526static int check_nocow_nolock(struct btrfs_inode *inode, loff_t pos,
1527 size_t *write_bytes)
1528{
1529 return check_can_nocow(inode, pos, write_bytes, true);
1530}
1531
1532/*
1533 * Check if we can do nocow write into the range [@pos, @pos + @write_bytes)
1534 *
1535 * @pos: File offset
1536 * @write_bytes: The length to write, will be updated to the nocow writeable
1537 * range
1538 *
1539 * This function will flush ordered extents in the range to ensure proper
1540 * nocow checks.
1541 *
1542 * Return:
1543 * >0 and update @write_bytes if we can do nocow write
1544 * 0 if we can't do nocow write
1545 * -EAGAIN if we can't get the needed lock or there are ordered extents
1546 * for * (nowait == true) case
1547 * <0 if other error happened
1548 *
1549 * NOTE: Callers need to release the lock by btrfs_check_nocow_unlock().
1550 */
1551int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
1552 size_t *write_bytes)
1553{
1554 return check_can_nocow(inode, pos, write_bytes, false);
1555}
1556
1557void btrfs_check_nocow_unlock(struct btrfs_inode *inode)
1558{
1559 btrfs_drew_write_unlock(&inode->root->snapshot_lock);
1560}
1561
1562static void update_time_for_write(struct inode *inode)
1563{
1564 struct timespec64 now;
1565
1566 if (IS_NOCMTIME(inode))
1567 return;
1568
1569 now = current_time(inode);
1570 if (!timespec64_equal(&inode->i_mtime, &now))
1571 inode->i_mtime = now;
1572
1573 if (!timespec64_equal(&inode->i_ctime, &now))
1574 inode->i_ctime = now;
1575
1576 if (IS_I_VERSION(inode))
1577 inode_inc_iversion(inode);
1578}
1579
1580static int btrfs_write_check(struct kiocb *iocb, struct iov_iter *from,
1581 size_t count)
1582{
1583 struct file *file = iocb->ki_filp;
1584 struct inode *inode = file_inode(file);
1585 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1586 loff_t pos = iocb->ki_pos;
1587 int ret;
1588 loff_t oldsize;
1589 loff_t start_pos;
1590
1591 if (iocb->ki_flags & IOCB_NOWAIT) {
1592 size_t nocow_bytes = count;
1593
1594 /* We will allocate space in case nodatacow is not set, so bail */
1595 if (check_nocow_nolock(BTRFS_I(inode), pos, &nocow_bytes) <= 0)
1596 return -EAGAIN;
1597 /*
1598 * There are holes in the range or parts of the range that must
1599 * be COWed (shared extents, RO block groups, etc), so just bail
1600 * out.
1601 */
1602 if (nocow_bytes < count)
1603 return -EAGAIN;
1604 }
1605
1606 current->backing_dev_info = inode_to_bdi(inode);
1607 ret = file_remove_privs(file);
1608 if (ret)
1609 return ret;
1610
1611 /*
1612 * We reserve space for updating the inode when we reserve space for the
1613 * extent we are going to write, so we will enospc out there. We don't
1614 * need to start yet another transaction to update the inode as we will
1615 * update the inode when we finish writing whatever data we write.
1616 */
1617 update_time_for_write(inode);
1618
1619 start_pos = round_down(pos, fs_info->sectorsize);
1620 oldsize = i_size_read(inode);
1621 if (start_pos > oldsize) {
1622 /* Expand hole size to cover write data, preventing empty gap */
1623 loff_t end_pos = round_up(pos + count, fs_info->sectorsize);
1624
1625 ret = btrfs_cont_expand(BTRFS_I(inode), oldsize, end_pos);
1626 if (ret) {
1627 current->backing_dev_info = NULL;
1628 return ret;
1629 }
1630 }
1631
1632 return 0;
1633}
1634
1635static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
1636 struct iov_iter *i)
1637{
1638 struct file *file = iocb->ki_filp;
1639 loff_t pos;
1640 struct inode *inode = file_inode(file);
1641 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1642 struct page **pages = NULL;
1643 struct extent_changeset *data_reserved = NULL;
1644 u64 release_bytes = 0;
1645 u64 lockstart;
1646 u64 lockend;
1647 size_t num_written = 0;
1648 int nrptrs;
1649 ssize_t ret;
1650 bool only_release_metadata = false;
1651 bool force_page_uptodate = false;
1652 loff_t old_isize = i_size_read(inode);
1653 unsigned int ilock_flags = 0;
1654
1655 if (iocb->ki_flags & IOCB_NOWAIT)
1656 ilock_flags |= BTRFS_ILOCK_TRY;
1657
1658 ret = btrfs_inode_lock(inode, ilock_flags);
1659 if (ret < 0)
1660 return ret;
1661
1662 ret = generic_write_checks(iocb, i);
1663 if (ret <= 0)
1664 goto out;
1665
1666 ret = btrfs_write_check(iocb, i, ret);
1667 if (ret < 0)
1668 goto out;
1669
1670 pos = iocb->ki_pos;
1671 nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
1672 PAGE_SIZE / (sizeof(struct page *)));
1673 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1674 nrptrs = max(nrptrs, 8);
1675 pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
1676 if (!pages) {
1677 ret = -ENOMEM;
1678 goto out;
1679 }
1680
1681 while (iov_iter_count(i) > 0) {
1682 struct extent_state *cached_state = NULL;
1683 size_t offset = offset_in_page(pos);
1684 size_t sector_offset;
1685 size_t write_bytes = min(iov_iter_count(i),
1686 nrptrs * (size_t)PAGE_SIZE -
1687 offset);
1688 size_t num_pages;
1689 size_t reserve_bytes;
1690 size_t dirty_pages;
1691 size_t copied;
1692 size_t dirty_sectors;
1693 size_t num_sectors;
1694 int extents_locked;
1695
1696 /*
1697 * Fault pages before locking them in prepare_pages
1698 * to avoid recursive lock
1699 */
1700 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1701 ret = -EFAULT;
1702 break;
1703 }
1704
1705 only_release_metadata = false;
1706 sector_offset = pos & (fs_info->sectorsize - 1);
1707
1708 extent_changeset_release(data_reserved);
1709 ret = btrfs_check_data_free_space(BTRFS_I(inode),
1710 &data_reserved, pos,
1711 write_bytes);
1712 if (ret < 0) {
1713 /*
1714 * If we don't have to COW at the offset, reserve
1715 * metadata only. write_bytes may get smaller than
1716 * requested here.
1717 */
1718 if (btrfs_check_nocow_lock(BTRFS_I(inode), pos,
1719 &write_bytes) > 0)
1720 only_release_metadata = true;
1721 else
1722 break;
1723 }
1724
1725 num_pages = DIV_ROUND_UP(write_bytes + offset, PAGE_SIZE);
1726 WARN_ON(num_pages > nrptrs);
1727 reserve_bytes = round_up(write_bytes + sector_offset,
1728 fs_info->sectorsize);
1729 WARN_ON(reserve_bytes == 0);
1730 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
1731 reserve_bytes);
1732 if (ret) {
1733 if (!only_release_metadata)
1734 btrfs_free_reserved_data_space(BTRFS_I(inode),
1735 data_reserved, pos,
1736 write_bytes);
1737 else
1738 btrfs_check_nocow_unlock(BTRFS_I(inode));
1739 break;
1740 }
1741
1742 release_bytes = reserve_bytes;
1743again:
1744 /*
1745 * This is going to setup the pages array with the number of
1746 * pages we want, so we don't really need to worry about the
1747 * contents of pages from loop to loop
1748 */
1749 ret = prepare_pages(inode, pages, num_pages,
1750 pos, write_bytes,
1751 force_page_uptodate);
1752 if (ret) {
1753 btrfs_delalloc_release_extents(BTRFS_I(inode),
1754 reserve_bytes);
1755 break;
1756 }
1757
1758 extents_locked = lock_and_cleanup_extent_if_need(
1759 BTRFS_I(inode), pages,
1760 num_pages, pos, write_bytes, &lockstart,
1761 &lockend, &cached_state);
1762 if (extents_locked < 0) {
1763 if (extents_locked == -EAGAIN)
1764 goto again;
1765 btrfs_delalloc_release_extents(BTRFS_I(inode),
1766 reserve_bytes);
1767 ret = extents_locked;
1768 break;
1769 }
1770
1771 copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
1772
1773 num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
1774 dirty_sectors = round_up(copied + sector_offset,
1775 fs_info->sectorsize);
1776 dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors);
1777
1778 /*
1779 * if we have trouble faulting in the pages, fall
1780 * back to one page at a time
1781 */
1782 if (copied < write_bytes)
1783 nrptrs = 1;
1784
1785 if (copied == 0) {
1786 force_page_uptodate = true;
1787 dirty_sectors = 0;
1788 dirty_pages = 0;
1789 } else {
1790 force_page_uptodate = false;
1791 dirty_pages = DIV_ROUND_UP(copied + offset,
1792 PAGE_SIZE);
1793 }
1794
1795 if (num_sectors > dirty_sectors) {
1796 /* release everything except the sectors we dirtied */
1797 release_bytes -= dirty_sectors << fs_info->sectorsize_bits;
1798 if (only_release_metadata) {
1799 btrfs_delalloc_release_metadata(BTRFS_I(inode),
1800 release_bytes, true);
1801 } else {
1802 u64 __pos;
1803
1804 __pos = round_down(pos,
1805 fs_info->sectorsize) +
1806 (dirty_pages << PAGE_SHIFT);
1807 btrfs_delalloc_release_space(BTRFS_I(inode),
1808 data_reserved, __pos,
1809 release_bytes, true);
1810 }
1811 }
1812
1813 release_bytes = round_up(copied + sector_offset,
1814 fs_info->sectorsize);
1815
1816 ret = btrfs_dirty_pages(BTRFS_I(inode), pages,
1817 dirty_pages, pos, copied,
1818 &cached_state, only_release_metadata);
1819
1820 /*
1821 * If we have not locked the extent range, because the range's
1822 * start offset is >= i_size, we might still have a non-NULL
1823 * cached extent state, acquired while marking the extent range
1824 * as delalloc through btrfs_dirty_pages(). Therefore free any
1825 * possible cached extent state to avoid a memory leak.
1826 */
1827 if (extents_locked)
1828 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1829 lockstart, lockend, &cached_state);
1830 else
1831 free_extent_state(cached_state);
1832
1833 btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
1834 if (ret) {
1835 btrfs_drop_pages(pages, num_pages);
1836 break;
1837 }
1838
1839 release_bytes = 0;
1840 if (only_release_metadata)
1841 btrfs_check_nocow_unlock(BTRFS_I(inode));
1842
1843 btrfs_drop_pages(pages, num_pages);
1844
1845 cond_resched();
1846
1847 balance_dirty_pages_ratelimited(inode->i_mapping);
1848
1849 pos += copied;
1850 num_written += copied;
1851 }
1852
1853 kfree(pages);
1854
1855 if (release_bytes) {
1856 if (only_release_metadata) {
1857 btrfs_check_nocow_unlock(BTRFS_I(inode));
1858 btrfs_delalloc_release_metadata(BTRFS_I(inode),
1859 release_bytes, true);
1860 } else {
1861 btrfs_delalloc_release_space(BTRFS_I(inode),
1862 data_reserved,
1863 round_down(pos, fs_info->sectorsize),
1864 release_bytes, true);
1865 }
1866 }
1867
1868 extent_changeset_free(data_reserved);
1869 if (num_written > 0) {
1870 pagecache_isize_extended(inode, old_isize, iocb->ki_pos);
1871 iocb->ki_pos += num_written;
1872 }
1873out:
1874 btrfs_inode_unlock(inode, ilock_flags);
1875 return num_written ? num_written : ret;
1876}
1877
1878static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
1879 const struct iov_iter *iter, loff_t offset)
1880{
1881 const u32 blocksize_mask = fs_info->sectorsize - 1;
1882
1883 if (offset & blocksize_mask)
1884 return -EINVAL;
1885
1886 if (iov_iter_alignment(iter) & blocksize_mask)
1887 return -EINVAL;
1888
1889 return 0;
1890}
1891
1892static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
1893{
1894 struct file *file = iocb->ki_filp;
1895 struct inode *inode = file_inode(file);
1896 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1897 loff_t pos;
1898 ssize_t written = 0;
1899 ssize_t written_buffered;
1900 loff_t endbyte;
1901 ssize_t err;
1902 unsigned int ilock_flags = 0;
1903 struct iomap_dio *dio = NULL;
1904
1905 if (iocb->ki_flags & IOCB_NOWAIT)
1906 ilock_flags |= BTRFS_ILOCK_TRY;
1907
1908 /* If the write DIO is within EOF, use a shared lock */
1909 if (iocb->ki_pos + iov_iter_count(from) <= i_size_read(inode))
1910 ilock_flags |= BTRFS_ILOCK_SHARED;
1911
1912relock:
1913 err = btrfs_inode_lock(inode, ilock_flags);
1914 if (err < 0)
1915 return err;
1916
1917 err = generic_write_checks(iocb, from);
1918 if (err <= 0) {
1919 btrfs_inode_unlock(inode, ilock_flags);
1920 return err;
1921 }
1922
1923 err = btrfs_write_check(iocb, from, err);
1924 if (err < 0) {
1925 btrfs_inode_unlock(inode, ilock_flags);
1926 goto out;
1927 }
1928
1929 pos = iocb->ki_pos;
1930 /*
1931 * Re-check since file size may have changed just before taking the
1932 * lock or pos may have changed because of O_APPEND in generic_write_check()
1933 */
1934 if ((ilock_flags & BTRFS_ILOCK_SHARED) &&
1935 pos + iov_iter_count(from) > i_size_read(inode)) {
1936 btrfs_inode_unlock(inode, ilock_flags);
1937 ilock_flags &= ~BTRFS_ILOCK_SHARED;
1938 goto relock;
1939 }
1940
1941 if (check_direct_IO(fs_info, from, pos)) {
1942 btrfs_inode_unlock(inode, ilock_flags);
1943 goto buffered;
1944 }
1945
1946 dio = __iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
1947 0);
1948
1949 btrfs_inode_unlock(inode, ilock_flags);
1950
1951 if (IS_ERR_OR_NULL(dio)) {
1952 err = PTR_ERR_OR_ZERO(dio);
1953 if (err < 0 && err != -ENOTBLK)
1954 goto out;
1955 } else {
1956 written = iomap_dio_complete(dio);
1957 }
1958
1959 if (written < 0 || !iov_iter_count(from)) {
1960 err = written;
1961 goto out;
1962 }
1963
1964buffered:
1965 pos = iocb->ki_pos;
1966 written_buffered = btrfs_buffered_write(iocb, from);
1967 if (written_buffered < 0) {
1968 err = written_buffered;
1969 goto out;
1970 }
1971 /*
1972 * Ensure all data is persisted. We want the next direct IO read to be
1973 * able to read what was just written.
1974 */
1975 endbyte = pos + written_buffered - 1;
1976 err = btrfs_fdatawrite_range(inode, pos, endbyte);
1977 if (err)
1978 goto out;
1979 err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
1980 if (err)
1981 goto out;
1982 written += written_buffered;
1983 iocb->ki_pos = pos + written_buffered;
1984 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT,
1985 endbyte >> PAGE_SHIFT);
1986out:
1987 return written ? written : err;
1988}
1989
1990static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
1991 struct iov_iter *from)
1992{
1993 struct file *file = iocb->ki_filp;
1994 struct btrfs_inode *inode = BTRFS_I(file_inode(file));
1995 ssize_t num_written = 0;
1996 const bool sync = iocb->ki_flags & IOCB_DSYNC;
1997
1998 /*
1999 * If the fs flips readonly due to some impossible error, although we
2000 * have opened a file as writable, we have to stop this write operation
2001 * to ensure consistency.
2002 */
2003 if (test_bit(BTRFS_FS_STATE_ERROR, &inode->root->fs_info->fs_state))
2004 return -EROFS;
2005
2006 if (!(iocb->ki_flags & IOCB_DIRECT) &&
2007 (iocb->ki_flags & IOCB_NOWAIT))
2008 return -EOPNOTSUPP;
2009
2010 if (sync)
2011 atomic_inc(&inode->sync_writers);
2012
2013 if (iocb->ki_flags & IOCB_DIRECT)
2014 num_written = btrfs_direct_write(iocb, from);
2015 else
2016 num_written = btrfs_buffered_write(iocb, from);
2017
2018 btrfs_set_inode_last_sub_trans(inode);
2019
2020 if (num_written > 0)
2021 num_written = generic_write_sync(iocb, num_written);
2022
2023 if (sync)
2024 atomic_dec(&inode->sync_writers);
2025
2026 current->backing_dev_info = NULL;
2027 return num_written;
2028}
2029
2030int btrfs_release_file(struct inode *inode, struct file *filp)
2031{
2032 struct btrfs_file_private *private = filp->private_data;
2033
2034 if (private && private->filldir_buf)
2035 kfree(private->filldir_buf);
2036 kfree(private);
2037 filp->private_data = NULL;
2038
2039 /*
2040 * Set by setattr when we are about to truncate a file from a non-zero
2041 * size to a zero size. This tries to flush down new bytes that may
2042 * have been written if the application were using truncate to replace
2043 * a file in place.
2044 */
2045 if (test_and_clear_bit(BTRFS_INODE_FLUSH_ON_CLOSE,
2046 &BTRFS_I(inode)->runtime_flags))
2047 filemap_flush(inode->i_mapping);
2048 return 0;
2049}
2050
2051static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
2052{
2053 int ret;
2054 struct blk_plug plug;
2055
2056 /*
2057 * This is only called in fsync, which would do synchronous writes, so
2058 * a plug can merge adjacent IOs as much as possible. Esp. in case of
2059 * multiple disks using raid profile, a large IO can be split to
2060 * several segments of stripe length (currently 64K).
2061 */
2062 blk_start_plug(&plug);
2063 atomic_inc(&BTRFS_I(inode)->sync_writers);
2064 ret = btrfs_fdatawrite_range(inode, start, end);
2065 atomic_dec(&BTRFS_I(inode)->sync_writers);
2066 blk_finish_plug(&plug);
2067
2068 return ret;
2069}
2070
2071static inline bool skip_inode_logging(const struct btrfs_log_ctx *ctx)
2072{
2073 struct btrfs_inode *inode = BTRFS_I(ctx->inode);
2074 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2075
2076 if (btrfs_inode_in_log(inode, fs_info->generation) &&
2077 list_empty(&ctx->ordered_extents))
2078 return true;
2079
2080 /*
2081 * If we are doing a fast fsync we can not bail out if the inode's
2082 * last_trans is <= then the last committed transaction, because we only
2083 * update the last_trans of the inode during ordered extent completion,
2084 * and for a fast fsync we don't wait for that, we only wait for the
2085 * writeback to complete.
2086 */
2087 if (inode->last_trans <= fs_info->last_trans_committed &&
2088 (test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags) ||
2089 list_empty(&ctx->ordered_extents)))
2090 return true;
2091
2092 return false;
2093}
2094
2095/*
2096 * fsync call for both files and directories. This logs the inode into
2097 * the tree log instead of forcing full commits whenever possible.
2098 *
2099 * It needs to call filemap_fdatawait so that all ordered extent updates are
2100 * in the metadata btree are up to date for copying to the log.
2101 *
2102 * It drops the inode mutex before doing the tree log commit. This is an
2103 * important optimization for directories because holding the mutex prevents
2104 * new operations on the dir while we write to disk.
2105 */
2106int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
2107{
2108 struct dentry *dentry = file_dentry(file);
2109 struct inode *inode = d_inode(dentry);
2110 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2111 struct btrfs_root *root = BTRFS_I(inode)->root;
2112 struct btrfs_trans_handle *trans;
2113 struct btrfs_log_ctx ctx;
2114 int ret = 0, err;
2115 u64 len;
2116 bool full_sync;
2117
2118 trace_btrfs_sync_file(file, datasync);
2119
2120 btrfs_init_log_ctx(&ctx, inode);
2121
2122 /*
2123 * Always set the range to a full range, otherwise we can get into
2124 * several problems, from missing file extent items to represent holes
2125 * when not using the NO_HOLES feature, to log tree corruption due to
2126 * races between hole detection during logging and completion of ordered
2127 * extents outside the range, to missing checksums due to ordered extents
2128 * for which we flushed only a subset of their pages.
2129 */
2130 start = 0;
2131 end = LLONG_MAX;
2132 len = (u64)LLONG_MAX + 1;
2133
2134 /*
2135 * We write the dirty pages in the range and wait until they complete
2136 * out of the ->i_mutex. If so, we can flush the dirty pages by
2137 * multi-task, and make the performance up. See
2138 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
2139 */
2140 ret = start_ordered_ops(inode, start, end);
2141 if (ret)
2142 goto out;
2143
2144 btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP);
2145
2146 atomic_inc(&root->log_batch);
2147
2148 /*
2149 * Always check for the full sync flag while holding the inode's lock,
2150 * to avoid races with other tasks. The flag must be either set all the
2151 * time during logging or always off all the time while logging.
2152 */
2153 full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2154 &BTRFS_I(inode)->runtime_flags);
2155
2156 /*
2157 * Before we acquired the inode's lock and the mmap lock, someone may
2158 * have dirtied more pages in the target range. We need to make sure
2159 * that writeback for any such pages does not start while we are logging
2160 * the inode, because if it does, any of the following might happen when
2161 * we are not doing a full inode sync:
2162 *
2163 * 1) We log an extent after its writeback finishes but before its
2164 * checksums are added to the csum tree, leading to -EIO errors
2165 * when attempting to read the extent after a log replay.
2166 *
2167 * 2) We can end up logging an extent before its writeback finishes.
2168 * Therefore after the log replay we will have a file extent item
2169 * pointing to an unwritten extent (and no data checksums as well).
2170 *
2171 * So trigger writeback for any eventual new dirty pages and then we
2172 * wait for all ordered extents to complete below.
2173 */
2174 ret = start_ordered_ops(inode, start, end);
2175 if (ret) {
2176 btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
2177 goto out;
2178 }
2179
2180 /*
2181 * We have to do this here to avoid the priority inversion of waiting on
2182 * IO of a lower priority task while holding a transaction open.
2183 *
2184 * For a full fsync we wait for the ordered extents to complete while
2185 * for a fast fsync we wait just for writeback to complete, and then
2186 * attach the ordered extents to the transaction so that a transaction
2187 * commit waits for their completion, to avoid data loss if we fsync,
2188 * the current transaction commits before the ordered extents complete
2189 * and a power failure happens right after that.
2190 *
2191 * For zoned filesystem, if a write IO uses a ZONE_APPEND command, the
2192 * logical address recorded in the ordered extent may change. We need
2193 * to wait for the IO to stabilize the logical address.
2194 */
2195 if (full_sync || btrfs_is_zoned(fs_info)) {
2196 ret = btrfs_wait_ordered_range(inode, start, len);
2197 } else {
2198 /*
2199 * Get our ordered extents as soon as possible to avoid doing
2200 * checksum lookups in the csum tree, and use instead the
2201 * checksums attached to the ordered extents.
2202 */
2203 btrfs_get_ordered_extents_for_logging(BTRFS_I(inode),
2204 &ctx.ordered_extents);
2205 ret = filemap_fdatawait_range(inode->i_mapping, start, end);
2206 }
2207
2208 if (ret)
2209 goto out_release_extents;
2210
2211 atomic_inc(&root->log_batch);
2212
2213 smp_mb();
2214 if (skip_inode_logging(&ctx)) {
2215 /*
2216 * We've had everything committed since the last time we were
2217 * modified so clear this flag in case it was set for whatever
2218 * reason, it's no longer relevant.
2219 */
2220 clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2221 &BTRFS_I(inode)->runtime_flags);
2222 /*
2223 * An ordered extent might have started before and completed
2224 * already with io errors, in which case the inode was not
2225 * updated and we end up here. So check the inode's mapping
2226 * for any errors that might have happened since we last
2227 * checked called fsync.
2228 */
2229 ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
2230 goto out_release_extents;
2231 }
2232
2233 /*
2234 * We use start here because we will need to wait on the IO to complete
2235 * in btrfs_sync_log, which could require joining a transaction (for
2236 * example checking cross references in the nocow path). If we use join
2237 * here we could get into a situation where we're waiting on IO to
2238 * happen that is blocked on a transaction trying to commit. With start
2239 * we inc the extwriter counter, so we wait for all extwriters to exit
2240 * before we start blocking joiners. This comment is to keep somebody
2241 * from thinking they are super smart and changing this to
2242 * btrfs_join_transaction *cough*Josef*cough*.
2243 */
2244 trans = btrfs_start_transaction(root, 0);
2245 if (IS_ERR(trans)) {
2246 ret = PTR_ERR(trans);
2247 goto out_release_extents;
2248 }
2249 trans->in_fsync = true;
2250
2251 ret = btrfs_log_dentry_safe(trans, dentry, &ctx);
2252 btrfs_release_log_ctx_extents(&ctx);
2253 if (ret < 0) {
2254 /* Fallthrough and commit/free transaction. */
2255 ret = 1;
2256 }
2257
2258 /* we've logged all the items and now have a consistent
2259 * version of the file in the log. It is possible that
2260 * someone will come in and modify the file, but that's
2261 * fine because the log is consistent on disk, and we
2262 * have references to all of the file's extents
2263 *
2264 * It is possible that someone will come in and log the
2265 * file again, but that will end up using the synchronization
2266 * inside btrfs_sync_log to keep things safe.
2267 */
2268 btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
2269
2270 if (ret != BTRFS_NO_LOG_SYNC) {
2271 if (!ret) {
2272 ret = btrfs_sync_log(trans, root, &ctx);
2273 if (!ret) {
2274 ret = btrfs_end_transaction(trans);
2275 goto out;
2276 }
2277 }
2278 if (!full_sync) {
2279 ret = btrfs_wait_ordered_range(inode, start, len);
2280 if (ret) {
2281 btrfs_end_transaction(trans);
2282 goto out;
2283 }
2284 }
2285 ret = btrfs_commit_transaction(trans);
2286 } else {
2287 ret = btrfs_end_transaction(trans);
2288 }
2289out:
2290 ASSERT(list_empty(&ctx.list));
2291 err = file_check_and_advance_wb_err(file);
2292 if (!ret)
2293 ret = err;
2294 return ret > 0 ? -EIO : ret;
2295
2296out_release_extents:
2297 btrfs_release_log_ctx_extents(&ctx);
2298 btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
2299 goto out;
2300}
2301
2302static const struct vm_operations_struct btrfs_file_vm_ops = {
2303 .fault = filemap_fault,
2304 .map_pages = filemap_map_pages,
2305 .page_mkwrite = btrfs_page_mkwrite,
2306};
2307
2308static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
2309{
2310 struct address_space *mapping = filp->f_mapping;
2311
2312 if (!mapping->a_ops->readpage)
2313 return -ENOEXEC;
2314
2315 file_accessed(filp);
2316 vma->vm_ops = &btrfs_file_vm_ops;
2317
2318 return 0;
2319}
2320
2321static int hole_mergeable(struct btrfs_inode *inode, struct extent_buffer *leaf,
2322 int slot, u64 start, u64 end)
2323{
2324 struct btrfs_file_extent_item *fi;
2325 struct btrfs_key key;
2326
2327 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
2328 return 0;
2329
2330 btrfs_item_key_to_cpu(leaf, &key, slot);
2331 if (key.objectid != btrfs_ino(inode) ||
2332 key.type != BTRFS_EXTENT_DATA_KEY)
2333 return 0;
2334
2335 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2336
2337 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2338 return 0;
2339
2340 if (btrfs_file_extent_disk_bytenr(leaf, fi))
2341 return 0;
2342
2343 if (key.offset == end)
2344 return 1;
2345 if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
2346 return 1;
2347 return 0;
2348}
2349
2350static int fill_holes(struct btrfs_trans_handle *trans,
2351 struct btrfs_inode *inode,
2352 struct btrfs_path *path, u64 offset, u64 end)
2353{
2354 struct btrfs_fs_info *fs_info = trans->fs_info;
2355 struct btrfs_root *root = inode->root;
2356 struct extent_buffer *leaf;
2357 struct btrfs_file_extent_item *fi;
2358 struct extent_map *hole_em;
2359 struct extent_map_tree *em_tree = &inode->extent_tree;
2360 struct btrfs_key key;
2361 int ret;
2362
2363 if (btrfs_fs_incompat(fs_info, NO_HOLES))
2364 goto out;
2365
2366 key.objectid = btrfs_ino(inode);
2367 key.type = BTRFS_EXTENT_DATA_KEY;
2368 key.offset = offset;
2369
2370 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2371 if (ret <= 0) {
2372 /*
2373 * We should have dropped this offset, so if we find it then
2374 * something has gone horribly wrong.
2375 */
2376 if (ret == 0)
2377 ret = -EINVAL;
2378 return ret;
2379 }
2380
2381 leaf = path->nodes[0];
2382 if (hole_mergeable(inode, leaf, path->slots[0] - 1, offset, end)) {
2383 u64 num_bytes;
2384
2385 path->slots[0]--;
2386 fi = btrfs_item_ptr(leaf, path->slots[0],
2387 struct btrfs_file_extent_item);
2388 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
2389 end - offset;
2390 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2391 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2392 btrfs_set_file_extent_offset(leaf, fi, 0);
2393 btrfs_mark_buffer_dirty(leaf);
2394 goto out;
2395 }
2396
2397 if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
2398 u64 num_bytes;
2399
2400 key.offset = offset;
2401 btrfs_set_item_key_safe(fs_info, path, &key);
2402 fi = btrfs_item_ptr(leaf, path->slots[0],
2403 struct btrfs_file_extent_item);
2404 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
2405 offset;
2406 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2407 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2408 btrfs_set_file_extent_offset(leaf, fi, 0);
2409 btrfs_mark_buffer_dirty(leaf);
2410 goto out;
2411 }
2412 btrfs_release_path(path);
2413
2414 ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode),
2415 offset, 0, 0, end - offset, 0, end - offset, 0, 0, 0);
2416 if (ret)
2417 return ret;
2418
2419out:
2420 btrfs_release_path(path);
2421
2422 hole_em = alloc_extent_map();
2423 if (!hole_em) {
2424 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2425 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
2426 } else {
2427 hole_em->start = offset;
2428 hole_em->len = end - offset;
2429 hole_em->ram_bytes = hole_em->len;
2430 hole_em->orig_start = offset;
2431
2432 hole_em->block_start = EXTENT_MAP_HOLE;
2433 hole_em->block_len = 0;
2434 hole_em->orig_block_len = 0;
2435 hole_em->compress_type = BTRFS_COMPRESS_NONE;
2436 hole_em->generation = trans->transid;
2437
2438 do {
2439 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2440 write_lock(&em_tree->lock);
2441 ret = add_extent_mapping(em_tree, hole_em, 1);
2442 write_unlock(&em_tree->lock);
2443 } while (ret == -EEXIST);
2444 free_extent_map(hole_em);
2445 if (ret)
2446 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2447 &inode->runtime_flags);
2448 }
2449
2450 return 0;
2451}
2452
2453/*
2454 * Find a hole extent on given inode and change start/len to the end of hole
2455 * extent.(hole/vacuum extent whose em->start <= start &&
2456 * em->start + em->len > start)
2457 * When a hole extent is found, return 1 and modify start/len.
2458 */
2459static int find_first_non_hole(struct btrfs_inode *inode, u64 *start, u64 *len)
2460{
2461 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2462 struct extent_map *em;
2463 int ret = 0;
2464
2465 em = btrfs_get_extent(inode, NULL, 0,
2466 round_down(*start, fs_info->sectorsize),
2467 round_up(*len, fs_info->sectorsize));
2468 if (IS_ERR(em))
2469 return PTR_ERR(em);
2470
2471 /* Hole or vacuum extent(only exists in no-hole mode) */
2472 if (em->block_start == EXTENT_MAP_HOLE) {
2473 ret = 1;
2474 *len = em->start + em->len > *start + *len ?
2475 0 : *start + *len - em->start - em->len;
2476 *start = em->start + em->len;
2477 }
2478 free_extent_map(em);
2479 return ret;
2480}
2481
2482static int btrfs_punch_hole_lock_range(struct inode *inode,
2483 const u64 lockstart,
2484 const u64 lockend,
2485 struct extent_state **cached_state)
2486{
2487 /*
2488 * For subpage case, if the range is not at page boundary, we could
2489 * have pages at the leading/tailing part of the range.
2490 * This could lead to dead loop since filemap_range_has_page()
2491 * will always return true.
2492 * So here we need to do extra page alignment for
2493 * filemap_range_has_page().
2494 */
2495 const u64 page_lockstart = round_up(lockstart, PAGE_SIZE);
2496 const u64 page_lockend = round_down(lockend + 1, PAGE_SIZE) - 1;
2497
2498 while (1) {
2499 struct btrfs_ordered_extent *ordered;
2500 int ret;
2501
2502 truncate_pagecache_range(inode, lockstart, lockend);
2503
2504 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2505 cached_state);
2506 ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode),
2507 lockend);
2508
2509 /*
2510 * We need to make sure we have no ordered extents in this range
2511 * and nobody raced in and read a page in this range, if we did
2512 * we need to try again.
2513 */
2514 if ((!ordered ||
2515 (ordered->file_offset + ordered->num_bytes <= lockstart ||
2516 ordered->file_offset > lockend)) &&
2517 !filemap_range_has_page(inode->i_mapping,
2518 page_lockstart, page_lockend)) {
2519 if (ordered)
2520 btrfs_put_ordered_extent(ordered);
2521 break;
2522 }
2523 if (ordered)
2524 btrfs_put_ordered_extent(ordered);
2525 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
2526 lockend, cached_state);
2527 ret = btrfs_wait_ordered_range(inode, lockstart,
2528 lockend - lockstart + 1);
2529 if (ret)
2530 return ret;
2531 }
2532 return 0;
2533}
2534
2535static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans,
2536 struct btrfs_inode *inode,
2537 struct btrfs_path *path,
2538 struct btrfs_replace_extent_info *extent_info,
2539 const u64 replace_len,
2540 const u64 bytes_to_drop)
2541{
2542 struct btrfs_fs_info *fs_info = trans->fs_info;
2543 struct btrfs_root *root = inode->root;
2544 struct btrfs_file_extent_item *extent;
2545 struct extent_buffer *leaf;
2546 struct btrfs_key key;
2547 int slot;
2548 struct btrfs_ref ref = { 0 };
2549 int ret;
2550
2551 if (replace_len == 0)
2552 return 0;
2553
2554 if (extent_info->disk_offset == 0 &&
2555 btrfs_fs_incompat(fs_info, NO_HOLES)) {
2556 btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
2557 return 0;
2558 }
2559
2560 key.objectid = btrfs_ino(inode);
2561 key.type = BTRFS_EXTENT_DATA_KEY;
2562 key.offset = extent_info->file_offset;
2563 ret = btrfs_insert_empty_item(trans, root, path, &key,
2564 sizeof(struct btrfs_file_extent_item));
2565 if (ret)
2566 return ret;
2567 leaf = path->nodes[0];
2568 slot = path->slots[0];
2569 write_extent_buffer(leaf, extent_info->extent_buf,
2570 btrfs_item_ptr_offset(leaf, slot),
2571 sizeof(struct btrfs_file_extent_item));
2572 extent = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2573 ASSERT(btrfs_file_extent_type(leaf, extent) != BTRFS_FILE_EXTENT_INLINE);
2574 btrfs_set_file_extent_offset(leaf, extent, extent_info->data_offset);
2575 btrfs_set_file_extent_num_bytes(leaf, extent, replace_len);
2576 if (extent_info->is_new_extent)
2577 btrfs_set_file_extent_generation(leaf, extent, trans->transid);
2578 btrfs_mark_buffer_dirty(leaf);
2579 btrfs_release_path(path);
2580
2581 ret = btrfs_inode_set_file_extent_range(inode, extent_info->file_offset,
2582 replace_len);
2583 if (ret)
2584 return ret;
2585
2586 /* If it's a hole, nothing more needs to be done. */
2587 if (extent_info->disk_offset == 0) {
2588 btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
2589 return 0;
2590 }
2591
2592 btrfs_update_inode_bytes(inode, replace_len, bytes_to_drop);
2593
2594 if (extent_info->is_new_extent && extent_info->insertions == 0) {
2595 key.objectid = extent_info->disk_offset;
2596 key.type = BTRFS_EXTENT_ITEM_KEY;
2597 key.offset = extent_info->disk_len;
2598 ret = btrfs_alloc_reserved_file_extent(trans, root,
2599 btrfs_ino(inode),
2600 extent_info->file_offset,
2601 extent_info->qgroup_reserved,
2602 &key);
2603 } else {
2604 u64 ref_offset;
2605
2606 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2607 extent_info->disk_offset,
2608 extent_info->disk_len, 0);
2609 ref_offset = extent_info->file_offset - extent_info->data_offset;
2610 btrfs_init_data_ref(&ref, root->root_key.objectid,
2611 btrfs_ino(inode), ref_offset);
2612 ret = btrfs_inc_extent_ref(trans, &ref);
2613 }
2614
2615 extent_info->insertions++;
2616
2617 return ret;
2618}
2619
2620/*
2621 * The respective range must have been previously locked, as well as the inode.
2622 * The end offset is inclusive (last byte of the range).
2623 * @extent_info is NULL for fallocate's hole punching and non-NULL when replacing
2624 * the file range with an extent.
2625 * When not punching a hole, we don't want to end up in a state where we dropped
2626 * extents without inserting a new one, so we must abort the transaction to avoid
2627 * a corruption.
2628 */
2629int btrfs_replace_file_extents(struct btrfs_inode *inode,
2630 struct btrfs_path *path, const u64 start,
2631 const u64 end,
2632 struct btrfs_replace_extent_info *extent_info,
2633 struct btrfs_trans_handle **trans_out)
2634{
2635 struct btrfs_drop_extents_args drop_args = { 0 };
2636 struct btrfs_root *root = inode->root;
2637 struct btrfs_fs_info *fs_info = root->fs_info;
2638 u64 min_size = btrfs_calc_insert_metadata_size(fs_info, 1);
2639 u64 ino_size = round_up(inode->vfs_inode.i_size, fs_info->sectorsize);
2640 struct btrfs_trans_handle *trans = NULL;
2641 struct btrfs_block_rsv *rsv;
2642 unsigned int rsv_count;
2643 u64 cur_offset;
2644 u64 len = end - start;
2645 int ret = 0;
2646
2647 if (end <= start)
2648 return -EINVAL;
2649
2650 rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
2651 if (!rsv) {
2652 ret = -ENOMEM;
2653 goto out;
2654 }
2655 rsv->size = btrfs_calc_insert_metadata_size(fs_info, 1);
2656 rsv->failfast = 1;
2657
2658 /*
2659 * 1 - update the inode
2660 * 1 - removing the extents in the range
2661 * 1 - adding the hole extent if no_holes isn't set or if we are
2662 * replacing the range with a new extent
2663 */
2664 if (!btrfs_fs_incompat(fs_info, NO_HOLES) || extent_info)
2665 rsv_count = 3;
2666 else
2667 rsv_count = 2;
2668
2669 trans = btrfs_start_transaction(root, rsv_count);
2670 if (IS_ERR(trans)) {
2671 ret = PTR_ERR(trans);
2672 trans = NULL;
2673 goto out_free;
2674 }
2675
2676 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
2677 min_size, false);
2678 BUG_ON(ret);
2679 trans->block_rsv = rsv;
2680
2681 cur_offset = start;
2682 drop_args.path = path;
2683 drop_args.end = end + 1;
2684 drop_args.drop_cache = true;
2685 while (cur_offset < end) {
2686 drop_args.start = cur_offset;
2687 ret = btrfs_drop_extents(trans, root, inode, &drop_args);
2688 /* If we are punching a hole decrement the inode's byte count */
2689 if (!extent_info)
2690 btrfs_update_inode_bytes(inode, 0,
2691 drop_args.bytes_found);
2692 if (ret != -ENOSPC) {
2693 /*
2694 * The only time we don't want to abort is if we are
2695 * attempting to clone a partial inline extent, in which
2696 * case we'll get EOPNOTSUPP. However if we aren't
2697 * clone we need to abort no matter what, because if we
2698 * got EOPNOTSUPP via prealloc then we messed up and
2699 * need to abort.
2700 */
2701 if (ret &&
2702 (ret != -EOPNOTSUPP ||
2703 (extent_info && extent_info->is_new_extent)))
2704 btrfs_abort_transaction(trans, ret);
2705 break;
2706 }
2707
2708 trans->block_rsv = &fs_info->trans_block_rsv;
2709
2710 if (!extent_info && cur_offset < drop_args.drop_end &&
2711 cur_offset < ino_size) {
2712 ret = fill_holes(trans, inode, path, cur_offset,
2713 drop_args.drop_end);
2714 if (ret) {
2715 /*
2716 * If we failed then we didn't insert our hole
2717 * entries for the area we dropped, so now the
2718 * fs is corrupted, so we must abort the
2719 * transaction.
2720 */
2721 btrfs_abort_transaction(trans, ret);
2722 break;
2723 }
2724 } else if (!extent_info && cur_offset < drop_args.drop_end) {
2725 /*
2726 * We are past the i_size here, but since we didn't
2727 * insert holes we need to clear the mapped area so we
2728 * know to not set disk_i_size in this area until a new
2729 * file extent is inserted here.
2730 */
2731 ret = btrfs_inode_clear_file_extent_range(inode,
2732 cur_offset,
2733 drop_args.drop_end - cur_offset);
2734 if (ret) {
2735 /*
2736 * We couldn't clear our area, so we could
2737 * presumably adjust up and corrupt the fs, so
2738 * we need to abort.
2739 */
2740 btrfs_abort_transaction(trans, ret);
2741 break;
2742 }
2743 }
2744
2745 if (extent_info &&
2746 drop_args.drop_end > extent_info->file_offset) {
2747 u64 replace_len = drop_args.drop_end -
2748 extent_info->file_offset;
2749
2750 ret = btrfs_insert_replace_extent(trans, inode, path,
2751 extent_info, replace_len,
2752 drop_args.bytes_found);
2753 if (ret) {
2754 btrfs_abort_transaction(trans, ret);
2755 break;
2756 }
2757 extent_info->data_len -= replace_len;
2758 extent_info->data_offset += replace_len;
2759 extent_info->file_offset += replace_len;
2760 }
2761
2762 ret = btrfs_update_inode(trans, root, inode);
2763 if (ret)
2764 break;
2765
2766 btrfs_end_transaction(trans);
2767 btrfs_btree_balance_dirty(fs_info);
2768
2769 trans = btrfs_start_transaction(root, rsv_count);
2770 if (IS_ERR(trans)) {
2771 ret = PTR_ERR(trans);
2772 trans = NULL;
2773 break;
2774 }
2775
2776 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
2777 rsv, min_size, false);
2778 BUG_ON(ret); /* shouldn't happen */
2779 trans->block_rsv = rsv;
2780
2781 cur_offset = drop_args.drop_end;
2782 len = end - cur_offset;
2783 if (!extent_info && len) {
2784 ret = find_first_non_hole(inode, &cur_offset, &len);
2785 if (unlikely(ret < 0))
2786 break;
2787 if (ret && !len) {
2788 ret = 0;
2789 break;
2790 }
2791 }
2792 }
2793
2794 /*
2795 * If we were cloning, force the next fsync to be a full one since we
2796 * we replaced (or just dropped in the case of cloning holes when
2797 * NO_HOLES is enabled) file extent items and did not setup new extent
2798 * maps for the replacement extents (or holes).
2799 */
2800 if (extent_info && !extent_info->is_new_extent)
2801 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
2802
2803 if (ret)
2804 goto out_trans;
2805
2806 trans->block_rsv = &fs_info->trans_block_rsv;
2807 /*
2808 * If we are using the NO_HOLES feature we might have had already an
2809 * hole that overlaps a part of the region [lockstart, lockend] and
2810 * ends at (or beyond) lockend. Since we have no file extent items to
2811 * represent holes, drop_end can be less than lockend and so we must
2812 * make sure we have an extent map representing the existing hole (the
2813 * call to __btrfs_drop_extents() might have dropped the existing extent
2814 * map representing the existing hole), otherwise the fast fsync path
2815 * will not record the existence of the hole region
2816 * [existing_hole_start, lockend].
2817 */
2818 if (drop_args.drop_end <= end)
2819 drop_args.drop_end = end + 1;
2820 /*
2821 * Don't insert file hole extent item if it's for a range beyond eof
2822 * (because it's useless) or if it represents a 0 bytes range (when
2823 * cur_offset == drop_end).
2824 */
2825 if (!extent_info && cur_offset < ino_size &&
2826 cur_offset < drop_args.drop_end) {
2827 ret = fill_holes(trans, inode, path, cur_offset,
2828 drop_args.drop_end);
2829 if (ret) {
2830 /* Same comment as above. */
2831 btrfs_abort_transaction(trans, ret);
2832 goto out_trans;
2833 }
2834 } else if (!extent_info && cur_offset < drop_args.drop_end) {
2835 /* See the comment in the loop above for the reasoning here. */
2836 ret = btrfs_inode_clear_file_extent_range(inode, cur_offset,
2837 drop_args.drop_end - cur_offset);
2838 if (ret) {
2839 btrfs_abort_transaction(trans, ret);
2840 goto out_trans;
2841 }
2842
2843 }
2844 if (extent_info) {
2845 ret = btrfs_insert_replace_extent(trans, inode, path,
2846 extent_info, extent_info->data_len,
2847 drop_args.bytes_found);
2848 if (ret) {
2849 btrfs_abort_transaction(trans, ret);
2850 goto out_trans;
2851 }
2852 }
2853
2854out_trans:
2855 if (!trans)
2856 goto out_free;
2857
2858 trans->block_rsv = &fs_info->trans_block_rsv;
2859 if (ret)
2860 btrfs_end_transaction(trans);
2861 else
2862 *trans_out = trans;
2863out_free:
2864 btrfs_free_block_rsv(fs_info, rsv);
2865out:
2866 return ret;
2867}
2868
2869static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
2870{
2871 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2872 struct btrfs_root *root = BTRFS_I(inode)->root;
2873 struct extent_state *cached_state = NULL;
2874 struct btrfs_path *path;
2875 struct btrfs_trans_handle *trans = NULL;
2876 u64 lockstart;
2877 u64 lockend;
2878 u64 tail_start;
2879 u64 tail_len;
2880 u64 orig_start = offset;
2881 int ret = 0;
2882 bool same_block;
2883 u64 ino_size;
2884 bool truncated_block = false;
2885 bool updated_inode = false;
2886
2887 ret = btrfs_wait_ordered_range(inode, offset, len);
2888 if (ret)
2889 return ret;
2890
2891 btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP);
2892 ino_size = round_up(inode->i_size, fs_info->sectorsize);
2893 ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
2894 if (ret < 0)
2895 goto out_only_mutex;
2896 if (ret && !len) {
2897 /* Already in a large hole */
2898 ret = 0;
2899 goto out_only_mutex;
2900 }
2901
2902 lockstart = round_up(offset, btrfs_inode_sectorsize(BTRFS_I(inode)));
2903 lockend = round_down(offset + len,
2904 btrfs_inode_sectorsize(BTRFS_I(inode))) - 1;
2905 same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset))
2906 == (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1));
2907 /*
2908 * We needn't truncate any block which is beyond the end of the file
2909 * because we are sure there is no data there.
2910 */
2911 /*
2912 * Only do this if we are in the same block and we aren't doing the
2913 * entire block.
2914 */
2915 if (same_block && len < fs_info->sectorsize) {
2916 if (offset < ino_size) {
2917 truncated_block = true;
2918 ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
2919 0);
2920 } else {
2921 ret = 0;
2922 }
2923 goto out_only_mutex;
2924 }
2925
2926 /* zero back part of the first block */
2927 if (offset < ino_size) {
2928 truncated_block = true;
2929 ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
2930 if (ret) {
2931 btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
2932 return ret;
2933 }
2934 }
2935
2936 /* Check the aligned pages after the first unaligned page,
2937 * if offset != orig_start, which means the first unaligned page
2938 * including several following pages are already in holes,
2939 * the extra check can be skipped */
2940 if (offset == orig_start) {
2941 /* after truncate page, check hole again */
2942 len = offset + len - lockstart;
2943 offset = lockstart;
2944 ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
2945 if (ret < 0)
2946 goto out_only_mutex;
2947 if (ret && !len) {
2948 ret = 0;
2949 goto out_only_mutex;
2950 }
2951 lockstart = offset;
2952 }
2953
2954 /* Check the tail unaligned part is in a hole */
2955 tail_start = lockend + 1;
2956 tail_len = offset + len - tail_start;
2957 if (tail_len) {
2958 ret = find_first_non_hole(BTRFS_I(inode), &tail_start, &tail_len);
2959 if (unlikely(ret < 0))
2960 goto out_only_mutex;
2961 if (!ret) {
2962 /* zero the front end of the last page */
2963 if (tail_start + tail_len < ino_size) {
2964 truncated_block = true;
2965 ret = btrfs_truncate_block(BTRFS_I(inode),
2966 tail_start + tail_len,
2967 0, 1);
2968 if (ret)
2969 goto out_only_mutex;
2970 }
2971 }
2972 }
2973
2974 if (lockend < lockstart) {
2975 ret = 0;
2976 goto out_only_mutex;
2977 }
2978
2979 ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
2980 &cached_state);
2981 if (ret)
2982 goto out_only_mutex;
2983
2984 path = btrfs_alloc_path();
2985 if (!path) {
2986 ret = -ENOMEM;
2987 goto out;
2988 }
2989
2990 ret = btrfs_replace_file_extents(BTRFS_I(inode), path, lockstart,
2991 lockend, NULL, &trans);
2992 btrfs_free_path(path);
2993 if (ret)
2994 goto out;
2995
2996 ASSERT(trans != NULL);
2997 inode_inc_iversion(inode);
2998 inode->i_mtime = inode->i_ctime = current_time(inode);
2999 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
3000 updated_inode = true;
3001 btrfs_end_transaction(trans);
3002 btrfs_btree_balance_dirty(fs_info);
3003out:
3004 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
3005 &cached_state);
3006out_only_mutex:
3007 if (!updated_inode && truncated_block && !ret) {
3008 /*
3009 * If we only end up zeroing part of a page, we still need to
3010 * update the inode item, so that all the time fields are
3011 * updated as well as the necessary btrfs inode in memory fields
3012 * for detecting, at fsync time, if the inode isn't yet in the
3013 * log tree or it's there but not up to date.
3014 */
3015 struct timespec64 now = current_time(inode);
3016
3017 inode_inc_iversion(inode);
3018 inode->i_mtime = now;
3019 inode->i_ctime = now;
3020 trans = btrfs_start_transaction(root, 1);
3021 if (IS_ERR(trans)) {
3022 ret = PTR_ERR(trans);
3023 } else {
3024 int ret2;
3025
3026 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
3027 ret2 = btrfs_end_transaction(trans);
3028 if (!ret)
3029 ret = ret2;
3030 }
3031 }
3032 btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
3033 return ret;
3034}
3035
3036/* Helper structure to record which range is already reserved */
3037struct falloc_range {
3038 struct list_head list;
3039 u64 start;
3040 u64 len;
3041};
3042
3043/*
3044 * Helper function to add falloc range
3045 *
3046 * Caller should have locked the larger range of extent containing
3047 * [start, len)
3048 */
3049static int add_falloc_range(struct list_head *head, u64 start, u64 len)
3050{
3051 struct falloc_range *range = NULL;
3052
3053 if (!list_empty(head)) {
3054 /*
3055 * As fallocate iterates by bytenr order, we only need to check
3056 * the last range.
3057 */
3058 range = list_last_entry(head, struct falloc_range, list);
3059 if (range->start + range->len == start) {
3060 range->len += len;
3061 return 0;
3062 }
3063 }
3064
3065 range = kmalloc(sizeof(*range), GFP_KERNEL);
3066 if (!range)
3067 return -ENOMEM;
3068 range->start = start;
3069 range->len = len;
3070 list_add_tail(&range->list, head);
3071 return 0;
3072}
3073
3074static int btrfs_fallocate_update_isize(struct inode *inode,
3075 const u64 end,
3076 const int mode)
3077{
3078 struct btrfs_trans_handle *trans;
3079 struct btrfs_root *root = BTRFS_I(inode)->root;
3080 int ret;
3081 int ret2;
3082
3083 if (mode & FALLOC_FL_KEEP_SIZE || end <= i_size_read(inode))
3084 return 0;
3085
3086 trans = btrfs_start_transaction(root, 1);
3087 if (IS_ERR(trans))
3088 return PTR_ERR(trans);
3089
3090 inode->i_ctime = current_time(inode);
3091 i_size_write(inode, end);
3092 btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
3093 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
3094 ret2 = btrfs_end_transaction(trans);
3095
3096 return ret ? ret : ret2;
3097}
3098
3099enum {
3100 RANGE_BOUNDARY_WRITTEN_EXTENT,
3101 RANGE_BOUNDARY_PREALLOC_EXTENT,
3102 RANGE_BOUNDARY_HOLE,
3103};
3104
3105static int btrfs_zero_range_check_range_boundary(struct btrfs_inode *inode,
3106 u64 offset)
3107{
3108 const u64 sectorsize = btrfs_inode_sectorsize(inode);
3109 struct extent_map *em;
3110 int ret;
3111
3112 offset = round_down(offset, sectorsize);
3113 em = btrfs_get_extent(inode, NULL, 0, offset, sectorsize);
3114 if (IS_ERR(em))
3115 return PTR_ERR(em);
3116
3117 if (em->block_start == EXTENT_MAP_HOLE)
3118 ret = RANGE_BOUNDARY_HOLE;
3119 else if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
3120 ret = RANGE_BOUNDARY_PREALLOC_EXTENT;
3121 else
3122 ret = RANGE_BOUNDARY_WRITTEN_EXTENT;
3123
3124 free_extent_map(em);
3125 return ret;
3126}
3127
3128static int btrfs_zero_range(struct inode *inode,
3129 loff_t offset,
3130 loff_t len,
3131 const int mode)
3132{
3133 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
3134 struct extent_map *em;
3135 struct extent_changeset *data_reserved = NULL;
3136 int ret;
3137 u64 alloc_hint = 0;
3138 const u64 sectorsize = btrfs_inode_sectorsize(BTRFS_I(inode));
3139 u64 alloc_start = round_down(offset, sectorsize);
3140 u64 alloc_end = round_up(offset + len, sectorsize);
3141 u64 bytes_to_reserve = 0;
3142 bool space_reserved = false;
3143
3144 inode_dio_wait(inode);
3145
3146 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
3147 alloc_end - alloc_start);
3148 if (IS_ERR(em)) {
3149 ret = PTR_ERR(em);
3150 goto out;
3151 }
3152
3153 /*
3154 * Avoid hole punching and extent allocation for some cases. More cases
3155 * could be considered, but these are unlikely common and we keep things
3156 * as simple as possible for now. Also, intentionally, if the target
3157 * range contains one or more prealloc extents together with regular
3158 * extents and holes, we drop all the existing extents and allocate a
3159 * new prealloc extent, so that we get a larger contiguous disk extent.
3160 */
3161 if (em->start <= alloc_start &&
3162 test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3163 const u64 em_end = em->start + em->len;
3164
3165 if (em_end >= offset + len) {
3166 /*
3167 * The whole range is already a prealloc extent,
3168 * do nothing except updating the inode's i_size if
3169 * needed.
3170 */
3171 free_extent_map(em);
3172 ret = btrfs_fallocate_update_isize(inode, offset + len,
3173 mode);
3174 goto out;
3175 }
3176 /*
3177 * Part of the range is already a prealloc extent, so operate
3178 * only on the remaining part of the range.
3179 */
3180 alloc_start = em_end;
3181 ASSERT(IS_ALIGNED(alloc_start, sectorsize));
3182 len = offset + len - alloc_start;
3183 offset = alloc_start;
3184 alloc_hint = em->block_start + em->len;
3185 }
3186 free_extent_map(em);
3187
3188 if (BTRFS_BYTES_TO_BLKS(fs_info, offset) ==
3189 BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)) {
3190 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
3191 sectorsize);
3192 if (IS_ERR(em)) {
3193 ret = PTR_ERR(em);
3194 goto out;
3195 }
3196
3197 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3198 free_extent_map(em);
3199 ret = btrfs_fallocate_update_isize(inode, offset + len,
3200 mode);
3201 goto out;
3202 }
3203 if (len < sectorsize && em->block_start != EXTENT_MAP_HOLE) {
3204 free_extent_map(em);
3205 ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
3206 0);
3207 if (!ret)
3208 ret = btrfs_fallocate_update_isize(inode,
3209 offset + len,
3210 mode);
3211 return ret;
3212 }
3213 free_extent_map(em);
3214 alloc_start = round_down(offset, sectorsize);
3215 alloc_end = alloc_start + sectorsize;
3216 goto reserve_space;
3217 }
3218
3219 alloc_start = round_up(offset, sectorsize);
3220 alloc_end = round_down(offset + len, sectorsize);
3221
3222 /*
3223 * For unaligned ranges, check the pages at the boundaries, they might
3224 * map to an extent, in which case we need to partially zero them, or
3225 * they might map to a hole, in which case we need our allocation range
3226 * to cover them.
3227 */
3228 if (!IS_ALIGNED(offset, sectorsize)) {
3229 ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
3230 offset);
3231 if (ret < 0)
3232 goto out;
3233 if (ret == RANGE_BOUNDARY_HOLE) {
3234 alloc_start = round_down(offset, sectorsize);
3235 ret = 0;
3236 } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
3237 ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
3238 if (ret)
3239 goto out;
3240 } else {
3241 ret = 0;
3242 }
3243 }
3244
3245 if (!IS_ALIGNED(offset + len, sectorsize)) {
3246 ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
3247 offset + len);
3248 if (ret < 0)
3249 goto out;
3250 if (ret == RANGE_BOUNDARY_HOLE) {
3251 alloc_end = round_up(offset + len, sectorsize);
3252 ret = 0;
3253 } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
3254 ret = btrfs_truncate_block(BTRFS_I(inode), offset + len,
3255 0, 1);
3256 if (ret)
3257 goto out;
3258 } else {
3259 ret = 0;
3260 }
3261 }
3262
3263reserve_space:
3264 if (alloc_start < alloc_end) {
3265 struct extent_state *cached_state = NULL;
3266 const u64 lockstart = alloc_start;
3267 const u64 lockend = alloc_end - 1;
3268
3269 bytes_to_reserve = alloc_end - alloc_start;
3270 ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
3271 bytes_to_reserve);
3272 if (ret < 0)
3273 goto out;
3274 space_reserved = true;
3275 ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
3276 &cached_state);
3277 if (ret)
3278 goto out;
3279 ret = btrfs_qgroup_reserve_data(BTRFS_I(inode), &data_reserved,
3280 alloc_start, bytes_to_reserve);
3281 if (ret) {
3282 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
3283 lockend, &cached_state);
3284 goto out;
3285 }
3286 ret = btrfs_prealloc_file_range(inode, mode, alloc_start,
3287 alloc_end - alloc_start,
3288 i_blocksize(inode),
3289 offset + len, &alloc_hint);
3290 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
3291 lockend, &cached_state);
3292 /* btrfs_prealloc_file_range releases reserved space on error */
3293 if (ret) {
3294 space_reserved = false;
3295 goto out;
3296 }
3297 }
3298 ret = btrfs_fallocate_update_isize(inode, offset + len, mode);
3299 out:
3300 if (ret && space_reserved)
3301 btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved,
3302 alloc_start, bytes_to_reserve);
3303 extent_changeset_free(data_reserved);
3304
3305 return ret;
3306}
3307
3308static long btrfs_fallocate(struct file *file, int mode,
3309 loff_t offset, loff_t len)
3310{
3311 struct inode *inode = file_inode(file);
3312 struct extent_state *cached_state = NULL;
3313 struct extent_changeset *data_reserved = NULL;
3314 struct falloc_range *range;
3315 struct falloc_range *tmp;
3316 struct list_head reserve_list;
3317 u64 cur_offset;
3318 u64 last_byte;
3319 u64 alloc_start;
3320 u64 alloc_end;
3321 u64 alloc_hint = 0;
3322 u64 locked_end;
3323 u64 actual_end = 0;
3324 struct extent_map *em;
3325 int blocksize = btrfs_inode_sectorsize(BTRFS_I(inode));
3326 int ret;
3327
3328 /* Do not allow fallocate in ZONED mode */
3329 if (btrfs_is_zoned(btrfs_sb(inode->i_sb)))
3330 return -EOPNOTSUPP;
3331
3332 alloc_start = round_down(offset, blocksize);
3333 alloc_end = round_up(offset + len, blocksize);
3334 cur_offset = alloc_start;
3335
3336 /* Make sure we aren't being give some crap mode */
3337 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
3338 FALLOC_FL_ZERO_RANGE))
3339 return -EOPNOTSUPP;
3340
3341 if (mode & FALLOC_FL_PUNCH_HOLE)
3342 return btrfs_punch_hole(inode, offset, len);
3343
3344 /*
3345 * Only trigger disk allocation, don't trigger qgroup reserve
3346 *
3347 * For qgroup space, it will be checked later.
3348 */
3349 if (!(mode & FALLOC_FL_ZERO_RANGE)) {
3350 ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
3351 alloc_end - alloc_start);
3352 if (ret < 0)
3353 return ret;
3354 }
3355
3356 btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP);
3357
3358 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) {
3359 ret = inode_newsize_ok(inode, offset + len);
3360 if (ret)
3361 goto out;
3362 }
3363
3364 /*
3365 * TODO: Move these two operations after we have checked
3366 * accurate reserved space, or fallocate can still fail but
3367 * with page truncated or size expanded.
3368 *
3369 * But that's a minor problem and won't do much harm BTW.
3370 */
3371 if (alloc_start > inode->i_size) {
3372 ret = btrfs_cont_expand(BTRFS_I(inode), i_size_read(inode),
3373 alloc_start);
3374 if (ret)
3375 goto out;
3376 } else if (offset + len > inode->i_size) {
3377 /*
3378 * If we are fallocating from the end of the file onward we
3379 * need to zero out the end of the block if i_size lands in the
3380 * middle of a block.
3381 */
3382 ret = btrfs_truncate_block(BTRFS_I(inode), inode->i_size, 0, 0);
3383 if (ret)
3384 goto out;
3385 }
3386
3387 /*
3388 * wait for ordered IO before we have any locks. We'll loop again
3389 * below with the locks held.
3390 */
3391 ret = btrfs_wait_ordered_range(inode, alloc_start,
3392 alloc_end - alloc_start);
3393 if (ret)
3394 goto out;
3395
3396 if (mode & FALLOC_FL_ZERO_RANGE) {
3397 ret = btrfs_zero_range(inode, offset, len, mode);
3398 btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
3399 return ret;
3400 }
3401
3402 locked_end = alloc_end - 1;
3403 while (1) {
3404 struct btrfs_ordered_extent *ordered;
3405
3406 /* the extent lock is ordered inside the running
3407 * transaction
3408 */
3409 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
3410 locked_end, &cached_state);
3411 ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode),
3412 locked_end);
3413
3414 if (ordered &&
3415 ordered->file_offset + ordered->num_bytes > alloc_start &&
3416 ordered->file_offset < alloc_end) {
3417 btrfs_put_ordered_extent(ordered);
3418 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
3419 alloc_start, locked_end,
3420 &cached_state);
3421 /*
3422 * we can't wait on the range with the transaction
3423 * running or with the extent lock held
3424 */
3425 ret = btrfs_wait_ordered_range(inode, alloc_start,
3426 alloc_end - alloc_start);
3427 if (ret)
3428 goto out;
3429 } else {
3430 if (ordered)
3431 btrfs_put_ordered_extent(ordered);
3432 break;
3433 }
3434 }
3435
3436 /* First, check if we exceed the qgroup limit */
3437 INIT_LIST_HEAD(&reserve_list);
3438 while (cur_offset < alloc_end) {
3439 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
3440 alloc_end - cur_offset);
3441 if (IS_ERR(em)) {
3442 ret = PTR_ERR(em);
3443 break;
3444 }
3445 last_byte = min(extent_map_end(em), alloc_end);
3446 actual_end = min_t(u64, extent_map_end(em), offset + len);
3447 last_byte = ALIGN(last_byte, blocksize);
3448 if (em->block_start == EXTENT_MAP_HOLE ||
3449 (cur_offset >= inode->i_size &&
3450 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
3451 ret = add_falloc_range(&reserve_list, cur_offset,
3452 last_byte - cur_offset);
3453 if (ret < 0) {
3454 free_extent_map(em);
3455 break;
3456 }
3457 ret = btrfs_qgroup_reserve_data(BTRFS_I(inode),
3458 &data_reserved, cur_offset,
3459 last_byte - cur_offset);
3460 if (ret < 0) {
3461 cur_offset = last_byte;
3462 free_extent_map(em);
3463 break;
3464 }
3465 } else {
3466 /*
3467 * Do not need to reserve unwritten extent for this
3468 * range, free reserved data space first, otherwise
3469 * it'll result in false ENOSPC error.
3470 */
3471 btrfs_free_reserved_data_space(BTRFS_I(inode),
3472 data_reserved, cur_offset,
3473 last_byte - cur_offset);
3474 }
3475 free_extent_map(em);
3476 cur_offset = last_byte;
3477 }
3478
3479 /*
3480 * If ret is still 0, means we're OK to fallocate.
3481 * Or just cleanup the list and exit.
3482 */
3483 list_for_each_entry_safe(range, tmp, &reserve_list, list) {
3484 if (!ret)
3485 ret = btrfs_prealloc_file_range(inode, mode,
3486 range->start,
3487 range->len, i_blocksize(inode),
3488 offset + len, &alloc_hint);
3489 else
3490 btrfs_free_reserved_data_space(BTRFS_I(inode),
3491 data_reserved, range->start,
3492 range->len);
3493 list_del(&range->list);
3494 kfree(range);
3495 }
3496 if (ret < 0)
3497 goto out_unlock;
3498
3499 /*
3500 * We didn't need to allocate any more space, but we still extended the
3501 * size of the file so we need to update i_size and the inode item.
3502 */
3503 ret = btrfs_fallocate_update_isize(inode, actual_end, mode);
3504out_unlock:
3505 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
3506 &cached_state);
3507out:
3508 btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
3509 /* Let go of our reservation. */
3510 if (ret != 0 && !(mode & FALLOC_FL_ZERO_RANGE))
3511 btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved,
3512 cur_offset, alloc_end - cur_offset);
3513 extent_changeset_free(data_reserved);
3514 return ret;
3515}
3516
3517static loff_t find_desired_extent(struct btrfs_inode *inode, loff_t offset,
3518 int whence)
3519{
3520 struct btrfs_fs_info *fs_info = inode->root->fs_info;
3521 struct extent_map *em = NULL;
3522 struct extent_state *cached_state = NULL;
3523 loff_t i_size = inode->vfs_inode.i_size;
3524 u64 lockstart;
3525 u64 lockend;
3526 u64 start;
3527 u64 len;
3528 int ret = 0;
3529
3530 if (i_size == 0 || offset >= i_size)
3531 return -ENXIO;
3532
3533 /*
3534 * offset can be negative, in this case we start finding DATA/HOLE from
3535 * the very start of the file.
3536 */
3537 start = max_t(loff_t, 0, offset);
3538
3539 lockstart = round_down(start, fs_info->sectorsize);
3540 lockend = round_up(i_size, fs_info->sectorsize);
3541 if (lockend <= lockstart)
3542 lockend = lockstart + fs_info->sectorsize;
3543 lockend--;
3544 len = lockend - lockstart + 1;
3545
3546 lock_extent_bits(&inode->io_tree, lockstart, lockend, &cached_state);
3547
3548 while (start < i_size) {
3549 em = btrfs_get_extent_fiemap(inode, start, len);
3550 if (IS_ERR(em)) {
3551 ret = PTR_ERR(em);
3552 em = NULL;
3553 break;
3554 }
3555
3556 if (whence == SEEK_HOLE &&
3557 (em->block_start == EXTENT_MAP_HOLE ||
3558 test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
3559 break;
3560 else if (whence == SEEK_DATA &&
3561 (em->block_start != EXTENT_MAP_HOLE &&
3562 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
3563 break;
3564
3565 start = em->start + em->len;
3566 free_extent_map(em);
3567 em = NULL;
3568 cond_resched();
3569 }
3570 free_extent_map(em);
3571 unlock_extent_cached(&inode->io_tree, lockstart, lockend,
3572 &cached_state);
3573 if (ret) {
3574 offset = ret;
3575 } else {
3576 if (whence == SEEK_DATA && start >= i_size)
3577 offset = -ENXIO;
3578 else
3579 offset = min_t(loff_t, start, i_size);
3580 }
3581
3582 return offset;
3583}
3584
3585static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
3586{
3587 struct inode *inode = file->f_mapping->host;
3588
3589 switch (whence) {
3590 default:
3591 return generic_file_llseek(file, offset, whence);
3592 case SEEK_DATA:
3593 case SEEK_HOLE:
3594 btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
3595 offset = find_desired_extent(BTRFS_I(inode), offset, whence);
3596 btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
3597 break;
3598 }
3599
3600 if (offset < 0)
3601 return offset;
3602
3603 return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
3604}
3605
3606static int btrfs_file_open(struct inode *inode, struct file *filp)
3607{
3608 filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
3609 return generic_file_open(inode, filp);
3610}
3611
3612static int check_direct_read(struct btrfs_fs_info *fs_info,
3613 const struct iov_iter *iter, loff_t offset)
3614{
3615 int ret;
3616 int i, seg;
3617
3618 ret = check_direct_IO(fs_info, iter, offset);
3619 if (ret < 0)
3620 return ret;
3621
3622 if (!iter_is_iovec(iter))
3623 return 0;
3624
3625 for (seg = 0; seg < iter->nr_segs; seg++)
3626 for (i = seg + 1; i < iter->nr_segs; i++)
3627 if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
3628 return -EINVAL;
3629 return 0;
3630}
3631
3632static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
3633{
3634 struct inode *inode = file_inode(iocb->ki_filp);
3635 ssize_t ret;
3636
3637 if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
3638 return 0;
3639
3640 btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
3641 ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops, 0);
3642 btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
3643 return ret;
3644}
3645
3646static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
3647{
3648 ssize_t ret = 0;
3649
3650 if (iocb->ki_flags & IOCB_DIRECT) {
3651 ret = btrfs_direct_read(iocb, to);
3652 if (ret < 0 || !iov_iter_count(to) ||
3653 iocb->ki_pos >= i_size_read(file_inode(iocb->ki_filp)))
3654 return ret;
3655 }
3656
3657 return filemap_read(iocb, to, ret);
3658}
3659
3660const struct file_operations btrfs_file_operations = {
3661 .llseek = btrfs_file_llseek,
3662 .read_iter = btrfs_file_read_iter,
3663 .splice_read = generic_file_splice_read,
3664 .write_iter = btrfs_file_write_iter,
3665 .splice_write = iter_file_splice_write,
3666 .mmap = btrfs_file_mmap,
3667 .open = btrfs_file_open,
3668 .release = btrfs_release_file,
3669 .fsync = btrfs_sync_file,
3670 .fallocate = btrfs_fallocate,
3671 .unlocked_ioctl = btrfs_ioctl,
3672#ifdef CONFIG_COMPAT
3673 .compat_ioctl = btrfs_compat_ioctl,
3674#endif
3675 .remap_file_range = btrfs_remap_file_range,
3676};
3677
3678void __cold btrfs_auto_defrag_exit(void)
3679{
3680 kmem_cache_destroy(btrfs_inode_defrag_cachep);
3681}
3682
3683int __init btrfs_auto_defrag_init(void)
3684{
3685 btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
3686 sizeof(struct inode_defrag), 0,
3687 SLAB_MEM_SPREAD,
3688 NULL);
3689 if (!btrfs_inode_defrag_cachep)
3690 return -ENOMEM;
3691
3692 return 0;
3693}
3694
3695int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
3696{
3697 int ret;
3698
3699 /*
3700 * So with compression we will find and lock a dirty page and clear the
3701 * first one as dirty, setup an async extent, and immediately return
3702 * with the entire range locked but with nobody actually marked with
3703 * writeback. So we can't just filemap_write_and_wait_range() and
3704 * expect it to work since it will just kick off a thread to do the
3705 * actual work. So we need to call filemap_fdatawrite_range _again_
3706 * since it will wait on the page lock, which won't be unlocked until
3707 * after the pages have been marked as writeback and so we're good to go
3708 * from there. We have to do this otherwise we'll miss the ordered
3709 * extents and that results in badness. Please Josef, do not think you
3710 * know better and pull this out at some point in the future, it is
3711 * right and you are wrong.
3712 */
3713 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3714 if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
3715 &BTRFS_I(inode)->runtime_flags))
3716 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3717
3718 return ret;
3719}