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1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/blkdev.h>
4#include <linux/iversion.h>
5#include "ctree.h"
6#include "fs.h"
7#include "messages.h"
8#include "compression.h"
9#include "delalloc-space.h"
10#include "disk-io.h"
11#include "reflink.h"
12#include "transaction.h"
13#include "subpage.h"
14#include "accessors.h"
15#include "file-item.h"
16#include "file.h"
17#include "super.h"
18
19#define BTRFS_MAX_DEDUPE_LEN SZ_16M
20
21static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
22 struct inode *inode,
23 u64 endoff,
24 const u64 destoff,
25 const u64 olen,
26 int no_time_update)
27{
28 int ret;
29
30 inode_inc_iversion(inode);
31 if (!no_time_update) {
32 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
33 }
34 /*
35 * We round up to the block size at eof when determining which
36 * extents to clone above, but shouldn't round up the file size.
37 */
38 if (endoff > destoff + olen)
39 endoff = destoff + olen;
40 if (endoff > inode->i_size) {
41 i_size_write(inode, endoff);
42 btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
43 }
44
45 ret = btrfs_update_inode(trans, BTRFS_I(inode));
46 if (ret) {
47 btrfs_abort_transaction(trans, ret);
48 btrfs_end_transaction(trans);
49 goto out;
50 }
51 ret = btrfs_end_transaction(trans);
52out:
53 return ret;
54}
55
56static int copy_inline_to_page(struct btrfs_inode *inode,
57 const u64 file_offset,
58 char *inline_data,
59 const u64 size,
60 const u64 datal,
61 const u8 comp_type)
62{
63 struct btrfs_fs_info *fs_info = inode->root->fs_info;
64 const u32 block_size = fs_info->sectorsize;
65 const u64 range_end = file_offset + block_size - 1;
66 const size_t inline_size = size - btrfs_file_extent_calc_inline_size(0);
67 char *data_start = inline_data + btrfs_file_extent_calc_inline_size(0);
68 struct extent_changeset *data_reserved = NULL;
69 struct folio *folio = NULL;
70 struct address_space *mapping = inode->vfs_inode.i_mapping;
71 int ret;
72
73 ASSERT(IS_ALIGNED(file_offset, block_size));
74
75 /*
76 * We have flushed and locked the ranges of the source and destination
77 * inodes, we also have locked the inodes, so we are safe to do a
78 * reservation here. Also we must not do the reservation while holding
79 * a transaction open, otherwise we would deadlock.
80 */
81 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, file_offset,
82 block_size);
83 if (ret)
84 goto out;
85
86 folio = __filemap_get_folio(mapping, file_offset >> PAGE_SHIFT,
87 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
88 btrfs_alloc_write_mask(mapping));
89 if (IS_ERR(folio)) {
90 ret = -ENOMEM;
91 goto out_unlock;
92 }
93
94 ret = set_folio_extent_mapped(folio);
95 if (ret < 0)
96 goto out_unlock;
97
98 clear_extent_bit(&inode->io_tree, file_offset, range_end,
99 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
100 NULL);
101 ret = btrfs_set_extent_delalloc(inode, file_offset, range_end, 0, NULL);
102 if (ret)
103 goto out_unlock;
104
105 /*
106 * After dirtying the page our caller will need to start a transaction,
107 * and if we are low on metadata free space, that can cause flushing of
108 * delalloc for all inodes in order to get metadata space released.
109 * However we are holding the range locked for the whole duration of
110 * the clone/dedupe operation, so we may deadlock if that happens and no
111 * other task releases enough space. So mark this inode as not being
112 * possible to flush to avoid such deadlock. We will clear that flag
113 * when we finish cloning all extents, since a transaction is started
114 * after finding each extent to clone.
115 */
116 set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags);
117
118 if (comp_type == BTRFS_COMPRESS_NONE) {
119 memcpy_to_folio(folio, offset_in_folio(folio, file_offset), data_start,
120 datal);
121 } else {
122 ret = btrfs_decompress(comp_type, data_start, folio,
123 offset_in_folio(folio, file_offset),
124 inline_size, datal);
125 if (ret)
126 goto out_unlock;
127 flush_dcache_folio(folio);
128 }
129
130 /*
131 * If our inline data is smaller then the block/page size, then the
132 * remaining of the block/page is equivalent to zeroes. We had something
133 * like the following done:
134 *
135 * $ xfs_io -f -c "pwrite -S 0xab 0 500" file
136 * $ sync # (or fsync)
137 * $ xfs_io -c "falloc 0 4K" file
138 * $ xfs_io -c "pwrite -S 0xcd 4K 4K"
139 *
140 * So what's in the range [500, 4095] corresponds to zeroes.
141 */
142 if (datal < block_size)
143 folio_zero_range(folio, datal, block_size - datal);
144
145 btrfs_folio_set_uptodate(fs_info, folio, file_offset, block_size);
146 btrfs_folio_clear_checked(fs_info, folio, file_offset, block_size);
147 btrfs_folio_set_dirty(fs_info, folio, file_offset, block_size);
148out_unlock:
149 if (!IS_ERR(folio)) {
150 folio_unlock(folio);
151 folio_put(folio);
152 }
153 if (ret)
154 btrfs_delalloc_release_space(inode, data_reserved, file_offset,
155 block_size, true);
156 btrfs_delalloc_release_extents(inode, block_size);
157out:
158 extent_changeset_free(data_reserved);
159
160 return ret;
161}
162
163/*
164 * Deal with cloning of inline extents. We try to copy the inline extent from
165 * the source inode to destination inode when possible. When not possible we
166 * copy the inline extent's data into the respective page of the inode.
167 */
168static int clone_copy_inline_extent(struct inode *dst,
169 struct btrfs_path *path,
170 struct btrfs_key *new_key,
171 const u64 drop_start,
172 const u64 datal,
173 const u64 size,
174 const u8 comp_type,
175 char *inline_data,
176 struct btrfs_trans_handle **trans_out)
177{
178 struct btrfs_fs_info *fs_info = inode_to_fs_info(dst);
179 struct btrfs_root *root = BTRFS_I(dst)->root;
180 const u64 aligned_end = ALIGN(new_key->offset + datal,
181 fs_info->sectorsize);
182 struct btrfs_trans_handle *trans = NULL;
183 struct btrfs_drop_extents_args drop_args = { 0 };
184 int ret;
185 struct btrfs_key key;
186
187 if (new_key->offset > 0) {
188 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
189 inline_data, size, datal, comp_type);
190 goto out;
191 }
192
193 key.objectid = btrfs_ino(BTRFS_I(dst));
194 key.type = BTRFS_EXTENT_DATA_KEY;
195 key.offset = 0;
196 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
197 if (ret < 0) {
198 return ret;
199 } else if (ret > 0) {
200 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
201 ret = btrfs_next_leaf(root, path);
202 if (ret < 0)
203 return ret;
204 else if (ret > 0)
205 goto copy_inline_extent;
206 }
207 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
208 if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
209 key.type == BTRFS_EXTENT_DATA_KEY) {
210 /*
211 * There's an implicit hole at file offset 0, copy the
212 * inline extent's data to the page.
213 */
214 ASSERT(key.offset > 0);
215 goto copy_to_page;
216 }
217 } else if (i_size_read(dst) <= datal) {
218 struct btrfs_file_extent_item *ei;
219
220 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
221 struct btrfs_file_extent_item);
222 /*
223 * If it's an inline extent replace it with the source inline
224 * extent, otherwise copy the source inline extent data into
225 * the respective page at the destination inode.
226 */
227 if (btrfs_file_extent_type(path->nodes[0], ei) ==
228 BTRFS_FILE_EXTENT_INLINE)
229 goto copy_inline_extent;
230
231 goto copy_to_page;
232 }
233
234copy_inline_extent:
235 /*
236 * We have no extent items, or we have an extent at offset 0 which may
237 * or may not be inlined. All these cases are dealt the same way.
238 */
239 if (i_size_read(dst) > datal) {
240 /*
241 * At the destination offset 0 we have either a hole, a regular
242 * extent or an inline extent larger then the one we want to
243 * clone. Deal with all these cases by copying the inline extent
244 * data into the respective page at the destination inode.
245 */
246 goto copy_to_page;
247 }
248
249 /*
250 * Release path before starting a new transaction so we don't hold locks
251 * that would confuse lockdep.
252 */
253 btrfs_release_path(path);
254 /*
255 * If we end up here it means were copy the inline extent into a leaf
256 * of the destination inode. We know we will drop or adjust at most one
257 * extent item in the destination root.
258 *
259 * 1 unit - adjusting old extent (we may have to split it)
260 * 1 unit - add new extent
261 * 1 unit - inode update
262 */
263 trans = btrfs_start_transaction(root, 3);
264 if (IS_ERR(trans)) {
265 ret = PTR_ERR(trans);
266 trans = NULL;
267 goto out;
268 }
269 drop_args.path = path;
270 drop_args.start = drop_start;
271 drop_args.end = aligned_end;
272 drop_args.drop_cache = true;
273 ret = btrfs_drop_extents(trans, root, BTRFS_I(dst), &drop_args);
274 if (ret)
275 goto out;
276 ret = btrfs_insert_empty_item(trans, root, path, new_key, size);
277 if (ret)
278 goto out;
279
280 write_extent_buffer(path->nodes[0], inline_data,
281 btrfs_item_ptr_offset(path->nodes[0],
282 path->slots[0]),
283 size);
284 btrfs_update_inode_bytes(BTRFS_I(dst), datal, drop_args.bytes_found);
285 btrfs_set_inode_full_sync(BTRFS_I(dst));
286 ret = btrfs_inode_set_file_extent_range(BTRFS_I(dst), 0, aligned_end);
287out:
288 if (!ret && !trans) {
289 /*
290 * No transaction here means we copied the inline extent into a
291 * page of the destination inode.
292 *
293 * 1 unit to update inode item
294 */
295 trans = btrfs_start_transaction(root, 1);
296 if (IS_ERR(trans)) {
297 ret = PTR_ERR(trans);
298 trans = NULL;
299 }
300 }
301 if (ret && trans) {
302 btrfs_abort_transaction(trans, ret);
303 btrfs_end_transaction(trans);
304 }
305 if (!ret)
306 *trans_out = trans;
307
308 return ret;
309
310copy_to_page:
311 /*
312 * Release our path because we don't need it anymore and also because
313 * copy_inline_to_page() needs to reserve data and metadata, which may
314 * need to flush delalloc when we are low on available space and
315 * therefore cause a deadlock if writeback of an inline extent needs to
316 * write to the same leaf or an ordered extent completion needs to write
317 * to the same leaf.
318 */
319 btrfs_release_path(path);
320
321 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
322 inline_data, size, datal, comp_type);
323 goto out;
324}
325
326/*
327 * Clone a range from inode file to another.
328 *
329 * @src: Inode to clone from
330 * @inode: Inode to clone to
331 * @off: Offset within source to start clone from
332 * @olen: Original length, passed by user, of range to clone
333 * @olen_aligned: Block-aligned value of olen
334 * @destoff: Offset within @inode to start clone
335 * @no_time_update: Whether to update mtime/ctime on the target inode
336 */
337static int btrfs_clone(struct inode *src, struct inode *inode,
338 const u64 off, const u64 olen, const u64 olen_aligned,
339 const u64 destoff, int no_time_update)
340{
341 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
342 struct btrfs_path *path = NULL;
343 struct extent_buffer *leaf;
344 struct btrfs_trans_handle *trans;
345 char *buf = NULL;
346 struct btrfs_key key;
347 u32 nritems;
348 int slot;
349 int ret;
350 const u64 len = olen_aligned;
351 u64 last_dest_end = destoff;
352 u64 prev_extent_end = off;
353
354 ret = -ENOMEM;
355 buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
356 if (!buf)
357 return ret;
358
359 path = btrfs_alloc_path();
360 if (!path) {
361 kvfree(buf);
362 return ret;
363 }
364
365 path->reada = READA_FORWARD;
366 /* Clone data */
367 key.objectid = btrfs_ino(BTRFS_I(src));
368 key.type = BTRFS_EXTENT_DATA_KEY;
369 key.offset = off;
370
371 while (1) {
372 struct btrfs_file_extent_item *extent;
373 u64 extent_gen;
374 int type;
375 u32 size;
376 struct btrfs_key new_key;
377 u64 disko = 0, diskl = 0;
378 u64 datao = 0, datal = 0;
379 u8 comp;
380 u64 drop_start;
381
382 /* Note the key will change type as we walk through the tree */
383 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
384 0, 0);
385 if (ret < 0)
386 goto out;
387 /*
388 * First search, if no extent item that starts at offset off was
389 * found but the previous item is an extent item, it's possible
390 * it might overlap our target range, therefore process it.
391 */
392 if (key.offset == off && ret > 0 && path->slots[0] > 0) {
393 btrfs_item_key_to_cpu(path->nodes[0], &key,
394 path->slots[0] - 1);
395 if (key.type == BTRFS_EXTENT_DATA_KEY)
396 path->slots[0]--;
397 }
398
399 nritems = btrfs_header_nritems(path->nodes[0]);
400process_slot:
401 if (path->slots[0] >= nritems) {
402 ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
403 if (ret < 0)
404 goto out;
405 if (ret > 0)
406 break;
407 nritems = btrfs_header_nritems(path->nodes[0]);
408 }
409 leaf = path->nodes[0];
410 slot = path->slots[0];
411
412 btrfs_item_key_to_cpu(leaf, &key, slot);
413 if (key.type > BTRFS_EXTENT_DATA_KEY ||
414 key.objectid != btrfs_ino(BTRFS_I(src)))
415 break;
416
417 ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
418
419 extent = btrfs_item_ptr(leaf, slot,
420 struct btrfs_file_extent_item);
421 extent_gen = btrfs_file_extent_generation(leaf, extent);
422 comp = btrfs_file_extent_compression(leaf, extent);
423 type = btrfs_file_extent_type(leaf, extent);
424 if (type == BTRFS_FILE_EXTENT_REG ||
425 type == BTRFS_FILE_EXTENT_PREALLOC) {
426 disko = btrfs_file_extent_disk_bytenr(leaf, extent);
427 diskl = btrfs_file_extent_disk_num_bytes(leaf, extent);
428 datao = btrfs_file_extent_offset(leaf, extent);
429 datal = btrfs_file_extent_num_bytes(leaf, extent);
430 } else if (type == BTRFS_FILE_EXTENT_INLINE) {
431 /* Take upper bound, may be compressed */
432 datal = btrfs_file_extent_ram_bytes(leaf, extent);
433 }
434
435 /*
436 * The first search might have left us at an extent item that
437 * ends before our target range's start, can happen if we have
438 * holes and NO_HOLES feature enabled.
439 *
440 * Subsequent searches may leave us on a file range we have
441 * processed before - this happens due to a race with ordered
442 * extent completion for a file range that is outside our source
443 * range, but that range was part of a file extent item that
444 * also covered a leading part of our source range.
445 */
446 if (key.offset + datal <= prev_extent_end) {
447 path->slots[0]++;
448 goto process_slot;
449 } else if (key.offset >= off + len) {
450 break;
451 }
452
453 prev_extent_end = key.offset + datal;
454 size = btrfs_item_size(leaf, slot);
455 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot),
456 size);
457
458 btrfs_release_path(path);
459
460 memcpy(&new_key, &key, sizeof(new_key));
461 new_key.objectid = btrfs_ino(BTRFS_I(inode));
462 if (off <= key.offset)
463 new_key.offset = key.offset + destoff - off;
464 else
465 new_key.offset = destoff;
466
467 /*
468 * Deal with a hole that doesn't have an extent item that
469 * represents it (NO_HOLES feature enabled).
470 * This hole is either in the middle of the cloning range or at
471 * the beginning (fully overlaps it or partially overlaps it).
472 */
473 if (new_key.offset != last_dest_end)
474 drop_start = last_dest_end;
475 else
476 drop_start = new_key.offset;
477
478 if (type == BTRFS_FILE_EXTENT_REG ||
479 type == BTRFS_FILE_EXTENT_PREALLOC) {
480 struct btrfs_replace_extent_info clone_info;
481
482 /*
483 * a | --- range to clone ---| b
484 * | ------------- extent ------------- |
485 */
486
487 /* Subtract range b */
488 if (key.offset + datal > off + len)
489 datal = off + len - key.offset;
490
491 /* Subtract range a */
492 if (off > key.offset) {
493 datao += off - key.offset;
494 datal -= off - key.offset;
495 }
496
497 clone_info.disk_offset = disko;
498 clone_info.disk_len = diskl;
499 clone_info.data_offset = datao;
500 clone_info.data_len = datal;
501 clone_info.file_offset = new_key.offset;
502 clone_info.extent_buf = buf;
503 clone_info.is_new_extent = false;
504 clone_info.update_times = !no_time_update;
505 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
506 drop_start, new_key.offset + datal - 1,
507 &clone_info, &trans);
508 if (ret)
509 goto out;
510 } else {
511 ASSERT(type == BTRFS_FILE_EXTENT_INLINE);
512 /*
513 * Inline extents always have to start at file offset 0
514 * and can never be bigger then the sector size. We can
515 * never clone only parts of an inline extent, since all
516 * reflink operations must start at a sector size aligned
517 * offset, and the length must be aligned too or end at
518 * the i_size (which implies the whole inlined data).
519 */
520 ASSERT(key.offset == 0);
521 ASSERT(datal <= fs_info->sectorsize);
522 if (WARN_ON(type != BTRFS_FILE_EXTENT_INLINE) ||
523 WARN_ON(key.offset != 0) ||
524 WARN_ON(datal > fs_info->sectorsize)) {
525 ret = -EUCLEAN;
526 goto out;
527 }
528
529 ret = clone_copy_inline_extent(inode, path, &new_key,
530 drop_start, datal, size,
531 comp, buf, &trans);
532 if (ret)
533 goto out;
534 }
535
536 btrfs_release_path(path);
537
538 /*
539 * Whenever we share an extent we update the last_reflink_trans
540 * of each inode to the current transaction. This is needed to
541 * make sure fsync does not log multiple checksum items with
542 * overlapping ranges (because some extent items might refer
543 * only to sections of the original extent). For the destination
544 * inode we do this regardless of the generation of the extents
545 * or even if they are inline extents or explicit holes, to make
546 * sure a full fsync does not skip them. For the source inode,
547 * we only need to update last_reflink_trans in case it's a new
548 * extent that is not a hole or an inline extent, to deal with
549 * the checksums problem on fsync.
550 */
551 if (extent_gen == trans->transid && disko > 0)
552 BTRFS_I(src)->last_reflink_trans = trans->transid;
553
554 BTRFS_I(inode)->last_reflink_trans = trans->transid;
555
556 last_dest_end = ALIGN(new_key.offset + datal,
557 fs_info->sectorsize);
558 ret = clone_finish_inode_update(trans, inode, last_dest_end,
559 destoff, olen, no_time_update);
560 if (ret)
561 goto out;
562 if (new_key.offset + datal >= destoff + len)
563 break;
564
565 btrfs_release_path(path);
566 key.offset = prev_extent_end;
567
568 if (fatal_signal_pending(current)) {
569 ret = -EINTR;
570 goto out;
571 }
572
573 cond_resched();
574 }
575 ret = 0;
576
577 if (last_dest_end < destoff + len) {
578 /*
579 * We have an implicit hole that fully or partially overlaps our
580 * cloning range at its end. This means that we either have the
581 * NO_HOLES feature enabled or the implicit hole happened due to
582 * mixing buffered and direct IO writes against this file.
583 */
584 btrfs_release_path(path);
585
586 /*
587 * When using NO_HOLES and we are cloning a range that covers
588 * only a hole (no extents) into a range beyond the current
589 * i_size, punching a hole in the target range will not create
590 * an extent map defining a hole, because the range starts at or
591 * beyond current i_size. If the file previously had an i_size
592 * greater than the new i_size set by this clone operation, we
593 * need to make sure the next fsync is a full fsync, so that it
594 * detects and logs a hole covering a range from the current
595 * i_size to the new i_size. If the clone range covers extents,
596 * besides a hole, then we know the full sync flag was already
597 * set by previous calls to btrfs_replace_file_extents() that
598 * replaced file extent items.
599 */
600 if (last_dest_end >= i_size_read(inode))
601 btrfs_set_inode_full_sync(BTRFS_I(inode));
602
603 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
604 last_dest_end, destoff + len - 1, NULL, &trans);
605 if (ret)
606 goto out;
607
608 ret = clone_finish_inode_update(trans, inode, destoff + len,
609 destoff, olen, no_time_update);
610 }
611
612out:
613 btrfs_free_path(path);
614 kvfree(buf);
615 clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &BTRFS_I(inode)->runtime_flags);
616
617 return ret;
618}
619
620static void btrfs_double_mmap_lock(struct inode *inode1, struct inode *inode2)
621{
622 if (inode1 < inode2)
623 swap(inode1, inode2);
624 down_write(&BTRFS_I(inode1)->i_mmap_lock);
625 down_write_nested(&BTRFS_I(inode2)->i_mmap_lock, SINGLE_DEPTH_NESTING);
626}
627
628static void btrfs_double_mmap_unlock(struct inode *inode1, struct inode *inode2)
629{
630 up_write(&BTRFS_I(inode1)->i_mmap_lock);
631 up_write(&BTRFS_I(inode2)->i_mmap_lock);
632}
633
634static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len,
635 struct inode *dst, u64 dst_loff)
636{
637 const u64 end = dst_loff + len - 1;
638 struct extent_state *cached_state = NULL;
639 struct btrfs_fs_info *fs_info = BTRFS_I(src)->root->fs_info;
640 const u64 bs = fs_info->sectorsize;
641 int ret;
642
643 /*
644 * Lock destination range to serialize with concurrent readahead(), and
645 * we are safe from concurrency with relocation of source extents
646 * because we have already locked the inode's i_mmap_lock in exclusive
647 * mode.
648 */
649 lock_extent(&BTRFS_I(dst)->io_tree, dst_loff, end, &cached_state);
650 ret = btrfs_clone(src, dst, loff, len, ALIGN(len, bs), dst_loff, 1);
651 unlock_extent(&BTRFS_I(dst)->io_tree, dst_loff, end, &cached_state);
652
653 btrfs_btree_balance_dirty(fs_info);
654
655 return ret;
656}
657
658static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
659 struct inode *dst, u64 dst_loff)
660{
661 int ret = 0;
662 u64 i, tail_len, chunk_count;
663 struct btrfs_root *root_dst = BTRFS_I(dst)->root;
664
665 spin_lock(&root_dst->root_item_lock);
666 if (root_dst->send_in_progress) {
667 btrfs_warn_rl(root_dst->fs_info,
668"cannot deduplicate to root %llu while send operations are using it (%d in progress)",
669 btrfs_root_id(root_dst),
670 root_dst->send_in_progress);
671 spin_unlock(&root_dst->root_item_lock);
672 return -EAGAIN;
673 }
674 root_dst->dedupe_in_progress++;
675 spin_unlock(&root_dst->root_item_lock);
676
677 tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
678 chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
679
680 for (i = 0; i < chunk_count; i++) {
681 ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,
682 dst, dst_loff);
683 if (ret)
684 goto out;
685
686 loff += BTRFS_MAX_DEDUPE_LEN;
687 dst_loff += BTRFS_MAX_DEDUPE_LEN;
688 }
689
690 if (tail_len > 0)
691 ret = btrfs_extent_same_range(src, loff, tail_len, dst, dst_loff);
692out:
693 spin_lock(&root_dst->root_item_lock);
694 root_dst->dedupe_in_progress--;
695 spin_unlock(&root_dst->root_item_lock);
696
697 return ret;
698}
699
700static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
701 u64 off, u64 olen, u64 destoff)
702{
703 struct extent_state *cached_state = NULL;
704 struct inode *inode = file_inode(file);
705 struct inode *src = file_inode(file_src);
706 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
707 int ret;
708 int wb_ret;
709 u64 len = olen;
710 u64 bs = fs_info->sectorsize;
711 u64 end;
712
713 /*
714 * VFS's generic_remap_file_range_prep() protects us from cloning the
715 * eof block into the middle of a file, which would result in corruption
716 * if the file size is not blocksize aligned. So we don't need to check
717 * for that case here.
718 */
719 if (off + len == src->i_size)
720 len = ALIGN(src->i_size, bs) - off;
721
722 if (destoff > inode->i_size) {
723 const u64 wb_start = ALIGN_DOWN(inode->i_size, bs);
724
725 ret = btrfs_cont_expand(BTRFS_I(inode), inode->i_size, destoff);
726 if (ret)
727 return ret;
728 /*
729 * We may have truncated the last block if the inode's size is
730 * not sector size aligned, so we need to wait for writeback to
731 * complete before proceeding further, otherwise we can race
732 * with cloning and attempt to increment a reference to an
733 * extent that no longer exists (writeback completed right after
734 * we found the previous extent covering eof and before we
735 * attempted to increment its reference count).
736 */
737 ret = btrfs_wait_ordered_range(BTRFS_I(inode), wb_start,
738 destoff - wb_start);
739 if (ret)
740 return ret;
741 }
742
743 /*
744 * Lock destination range to serialize with concurrent readahead(), and
745 * we are safe from concurrency with relocation of source extents
746 * because we have already locked the inode's i_mmap_lock in exclusive
747 * mode.
748 */
749 end = destoff + len - 1;
750 lock_extent(&BTRFS_I(inode)->io_tree, destoff, end, &cached_state);
751 ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
752 unlock_extent(&BTRFS_I(inode)->io_tree, destoff, end, &cached_state);
753
754 /*
755 * We may have copied an inline extent into a page of the destination
756 * range, so wait for writeback to complete before truncating pages
757 * from the page cache. This is a rare case.
758 */
759 wb_ret = btrfs_wait_ordered_range(BTRFS_I(inode), destoff, len);
760 ret = ret ? ret : wb_ret;
761 /*
762 * Truncate page cache pages so that future reads will see the cloned
763 * data immediately and not the previous data.
764 */
765 truncate_inode_pages_range(&inode->i_data,
766 round_down(destoff, PAGE_SIZE),
767 round_up(destoff + len, PAGE_SIZE) - 1);
768
769 btrfs_btree_balance_dirty(fs_info);
770
771 return ret;
772}
773
774static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in,
775 struct file *file_out, loff_t pos_out,
776 loff_t *len, unsigned int remap_flags)
777{
778 struct inode *inode_in = file_inode(file_in);
779 struct inode *inode_out = file_inode(file_out);
780 u64 bs = BTRFS_I(inode_out)->root->fs_info->sectorsize;
781 u64 wb_len;
782 int ret;
783
784 if (!(remap_flags & REMAP_FILE_DEDUP)) {
785 struct btrfs_root *root_out = BTRFS_I(inode_out)->root;
786
787 if (btrfs_root_readonly(root_out))
788 return -EROFS;
789
790 ASSERT(inode_in->i_sb == inode_out->i_sb);
791 }
792
793 /* Don't make the dst file partly checksummed */
794 if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) !=
795 (BTRFS_I(inode_out)->flags & BTRFS_INODE_NODATASUM)) {
796 return -EINVAL;
797 }
798
799 /*
800 * Now that the inodes are locked, we need to start writeback ourselves
801 * and can not rely on the writeback from the VFS's generic helper
802 * generic_remap_file_range_prep() because:
803 *
804 * 1) For compression we must call filemap_fdatawrite_range() range
805 * twice (btrfs_fdatawrite_range() does it for us), and the generic
806 * helper only calls it once;
807 *
808 * 2) filemap_fdatawrite_range(), called by the generic helper only
809 * waits for the writeback to complete, i.e. for IO to be done, and
810 * not for the ordered extents to complete. We need to wait for them
811 * to complete so that new file extent items are in the fs tree.
812 */
813 if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP))
814 wb_len = ALIGN(inode_in->i_size, bs) - ALIGN_DOWN(pos_in, bs);
815 else
816 wb_len = ALIGN(*len, bs);
817
818 /*
819 * Workaround to make sure NOCOW buffered write reach disk as NOCOW.
820 *
821 * Btrfs' back references do not have a block level granularity, they
822 * work at the whole extent level.
823 * NOCOW buffered write without data space reserved may not be able
824 * to fall back to CoW due to lack of data space, thus could cause
825 * data loss.
826 *
827 * Here we take a shortcut by flushing the whole inode, so that all
828 * nocow write should reach disk as nocow before we increase the
829 * reference of the extent. We could do better by only flushing NOCOW
830 * data, but that needs extra accounting.
831 *
832 * Also we don't need to check ASYNC_EXTENT, as async extent will be
833 * CoWed anyway, not affecting nocow part.
834 */
835 ret = filemap_flush(inode_in->i_mapping);
836 if (ret < 0)
837 return ret;
838
839 ret = btrfs_wait_ordered_range(BTRFS_I(inode_in), ALIGN_DOWN(pos_in, bs),
840 wb_len);
841 if (ret < 0)
842 return ret;
843 ret = btrfs_wait_ordered_range(BTRFS_I(inode_out), ALIGN_DOWN(pos_out, bs),
844 wb_len);
845 if (ret < 0)
846 return ret;
847
848 return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
849 len, remap_flags);
850}
851
852static bool file_sync_write(const struct file *file)
853{
854 if (file->f_flags & (__O_SYNC | O_DSYNC))
855 return true;
856 if (IS_SYNC(file_inode(file)))
857 return true;
858
859 return false;
860}
861
862loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
863 struct file *dst_file, loff_t destoff, loff_t len,
864 unsigned int remap_flags)
865{
866 struct inode *src_inode = file_inode(src_file);
867 struct inode *dst_inode = file_inode(dst_file);
868 bool same_inode = dst_inode == src_inode;
869 int ret;
870
871 if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
872 return -EINVAL;
873
874 if (same_inode) {
875 btrfs_inode_lock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);
876 } else {
877 lock_two_nondirectories(src_inode, dst_inode);
878 btrfs_double_mmap_lock(src_inode, dst_inode);
879 }
880
881 ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff,
882 &len, remap_flags);
883 if (ret < 0 || len == 0)
884 goto out_unlock;
885
886 if (remap_flags & REMAP_FILE_DEDUP)
887 ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff);
888 else
889 ret = btrfs_clone_files(dst_file, src_file, off, len, destoff);
890
891out_unlock:
892 if (same_inode) {
893 btrfs_inode_unlock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);
894 } else {
895 btrfs_double_mmap_unlock(src_inode, dst_inode);
896 unlock_two_nondirectories(src_inode, dst_inode);
897 }
898
899 /*
900 * If either the source or the destination file was opened with O_SYNC,
901 * O_DSYNC or has the S_SYNC attribute, fsync both the destination and
902 * source files/ranges, so that after a successful return (0) followed
903 * by a power failure results in the reflinked data to be readable from
904 * both files/ranges.
905 */
906 if (ret == 0 && len > 0 &&
907 (file_sync_write(src_file) || file_sync_write(dst_file))) {
908 ret = btrfs_sync_file(src_file, off, off + len - 1, 0);
909 if (ret == 0)
910 ret = btrfs_sync_file(dst_file, destoff,
911 destoff + len - 1, 0);
912 }
913
914 return ret < 0 ? ret : len;
915}