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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 struct btrfs_root *root = BTRFS_I(inode)->root;
29 int ret;
30
31 inode_inc_iversion(inode);
32 if (!no_time_update) {
33 inode->i_mtime = current_time(inode);
34 inode->i_ctime = inode->i_mtime;
35 }
36 /*
37 * We round up to the block size at eof when determining which
38 * extents to clone above, but shouldn't round up the file size.
39 */
40 if (endoff > destoff + olen)
41 endoff = destoff + olen;
42 if (endoff > inode->i_size) {
43 i_size_write(inode, endoff);
44 btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
45 }
46
47 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
48 if (ret) {
49 btrfs_abort_transaction(trans, ret);
50 btrfs_end_transaction(trans);
51 goto out;
52 }
53 ret = btrfs_end_transaction(trans);
54out:
55 return ret;
56}
57
58static int copy_inline_to_page(struct btrfs_inode *inode,
59 const u64 file_offset,
60 char *inline_data,
61 const u64 size,
62 const u64 datal,
63 const u8 comp_type)
64{
65 struct btrfs_fs_info *fs_info = inode->root->fs_info;
66 const u32 block_size = fs_info->sectorsize;
67 const u64 range_end = file_offset + block_size - 1;
68 const size_t inline_size = size - btrfs_file_extent_calc_inline_size(0);
69 char *data_start = inline_data + btrfs_file_extent_calc_inline_size(0);
70 struct extent_changeset *data_reserved = NULL;
71 struct page *page = NULL;
72 struct address_space *mapping = inode->vfs_inode.i_mapping;
73 int ret;
74
75 ASSERT(IS_ALIGNED(file_offset, block_size));
76
77 /*
78 * We have flushed and locked the ranges of the source and destination
79 * inodes, we also have locked the inodes, so we are safe to do a
80 * reservation here. Also we must not do the reservation while holding
81 * a transaction open, otherwise we would deadlock.
82 */
83 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, file_offset,
84 block_size);
85 if (ret)
86 goto out;
87
88 page = find_or_create_page(mapping, file_offset >> PAGE_SHIFT,
89 btrfs_alloc_write_mask(mapping));
90 if (!page) {
91 ret = -ENOMEM;
92 goto out_unlock;
93 }
94
95 ret = set_page_extent_mapped(page);
96 if (ret < 0)
97 goto out_unlock;
98
99 clear_extent_bit(&inode->io_tree, file_offset, range_end,
100 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
101 NULL);
102 ret = btrfs_set_extent_delalloc(inode, file_offset, range_end, 0, NULL);
103 if (ret)
104 goto out_unlock;
105
106 /*
107 * After dirtying the page our caller will need to start a transaction,
108 * and if we are low on metadata free space, that can cause flushing of
109 * delalloc for all inodes in order to get metadata space released.
110 * However we are holding the range locked for the whole duration of
111 * the clone/dedupe operation, so we may deadlock if that happens and no
112 * other task releases enough space. So mark this inode as not being
113 * possible to flush to avoid such deadlock. We will clear that flag
114 * when we finish cloning all extents, since a transaction is started
115 * after finding each extent to clone.
116 */
117 set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags);
118
119 if (comp_type == BTRFS_COMPRESS_NONE) {
120 memcpy_to_page(page, offset_in_page(file_offset), data_start,
121 datal);
122 } else {
123 ret = btrfs_decompress(comp_type, data_start, page,
124 offset_in_page(file_offset),
125 inline_size, datal);
126 if (ret)
127 goto out_unlock;
128 flush_dcache_page(page);
129 }
130
131 /*
132 * If our inline data is smaller then the block/page size, then the
133 * remaining of the block/page is equivalent to zeroes. We had something
134 * like the following done:
135 *
136 * $ xfs_io -f -c "pwrite -S 0xab 0 500" file
137 * $ sync # (or fsync)
138 * $ xfs_io -c "falloc 0 4K" file
139 * $ xfs_io -c "pwrite -S 0xcd 4K 4K"
140 *
141 * So what's in the range [500, 4095] corresponds to zeroes.
142 */
143 if (datal < block_size)
144 memzero_page(page, datal, block_size - datal);
145
146 btrfs_page_set_uptodate(fs_info, page, file_offset, block_size);
147 btrfs_page_clear_checked(fs_info, page, file_offset, block_size);
148 btrfs_page_set_dirty(fs_info, page, file_offset, block_size);
149out_unlock:
150 if (page) {
151 unlock_page(page);
152 put_page(page);
153 }
154 if (ret)
155 btrfs_delalloc_release_space(inode, data_reserved, file_offset,
156 block_size, true);
157 btrfs_delalloc_release_extents(inode, block_size);
158out:
159 extent_changeset_free(data_reserved);
160
161 return ret;
162}
163
164/*
165 * Deal with cloning of inline extents. We try to copy the inline extent from
166 * the source inode to destination inode when possible. When not possible we
167 * copy the inline extent's data into the respective page of the inode.
168 */
169static int clone_copy_inline_extent(struct inode *dst,
170 struct btrfs_path *path,
171 struct btrfs_key *new_key,
172 const u64 drop_start,
173 const u64 datal,
174 const u64 size,
175 const u8 comp_type,
176 char *inline_data,
177 struct btrfs_trans_handle **trans_out)
178{
179 struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb);
180 struct btrfs_root *root = BTRFS_I(dst)->root;
181 const u64 aligned_end = ALIGN(new_key->offset + datal,
182 fs_info->sectorsize);
183 struct btrfs_trans_handle *trans = NULL;
184 struct btrfs_drop_extents_args drop_args = { 0 };
185 int ret;
186 struct btrfs_key key;
187
188 if (new_key->offset > 0) {
189 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
190 inline_data, size, datal, comp_type);
191 goto out;
192 }
193
194 key.objectid = btrfs_ino(BTRFS_I(dst));
195 key.type = BTRFS_EXTENT_DATA_KEY;
196 key.offset = 0;
197 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
198 if (ret < 0) {
199 return ret;
200 } else if (ret > 0) {
201 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
202 ret = btrfs_next_leaf(root, path);
203 if (ret < 0)
204 return ret;
205 else if (ret > 0)
206 goto copy_inline_extent;
207 }
208 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
209 if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
210 key.type == BTRFS_EXTENT_DATA_KEY) {
211 /*
212 * There's an implicit hole at file offset 0, copy the
213 * inline extent's data to the page.
214 */
215 ASSERT(key.offset > 0);
216 goto copy_to_page;
217 }
218 } else if (i_size_read(dst) <= datal) {
219 struct btrfs_file_extent_item *ei;
220
221 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
222 struct btrfs_file_extent_item);
223 /*
224 * If it's an inline extent replace it with the source inline
225 * extent, otherwise copy the source inline extent data into
226 * the respective page at the destination inode.
227 */
228 if (btrfs_file_extent_type(path->nodes[0], ei) ==
229 BTRFS_FILE_EXTENT_INLINE)
230 goto copy_inline_extent;
231
232 goto copy_to_page;
233 }
234
235copy_inline_extent:
236 /*
237 * We have no extent items, or we have an extent at offset 0 which may
238 * or may not be inlined. All these cases are dealt the same way.
239 */
240 if (i_size_read(dst) > datal) {
241 /*
242 * At the destination offset 0 we have either a hole, a regular
243 * extent or an inline extent larger then the one we want to
244 * clone. Deal with all these cases by copying the inline extent
245 * data into the respective page at the destination inode.
246 */
247 goto copy_to_page;
248 }
249
250 /*
251 * Release path before starting a new transaction so we don't hold locks
252 * that would confuse lockdep.
253 */
254 btrfs_release_path(path);
255 /*
256 * If we end up here it means were copy the inline extent into a leaf
257 * of the destination inode. We know we will drop or adjust at most one
258 * extent item in the destination root.
259 *
260 * 1 unit - adjusting old extent (we may have to split it)
261 * 1 unit - add new extent
262 * 1 unit - inode update
263 */
264 trans = btrfs_start_transaction(root, 3);
265 if (IS_ERR(trans)) {
266 ret = PTR_ERR(trans);
267 trans = NULL;
268 goto out;
269 }
270 drop_args.path = path;
271 drop_args.start = drop_start;
272 drop_args.end = aligned_end;
273 drop_args.drop_cache = true;
274 ret = btrfs_drop_extents(trans, root, BTRFS_I(dst), &drop_args);
275 if (ret)
276 goto out;
277 ret = btrfs_insert_empty_item(trans, root, path, new_key, size);
278 if (ret)
279 goto out;
280
281 write_extent_buffer(path->nodes[0], inline_data,
282 btrfs_item_ptr_offset(path->nodes[0],
283 path->slots[0]),
284 size);
285 btrfs_update_inode_bytes(BTRFS_I(dst), datal, drop_args.bytes_found);
286 btrfs_set_inode_full_sync(BTRFS_I(dst));
287 ret = btrfs_inode_set_file_extent_range(BTRFS_I(dst), 0, aligned_end);
288out:
289 if (!ret && !trans) {
290 /*
291 * No transaction here means we copied the inline extent into a
292 * page of the destination inode.
293 *
294 * 1 unit to update inode item
295 */
296 trans = btrfs_start_transaction(root, 1);
297 if (IS_ERR(trans)) {
298 ret = PTR_ERR(trans);
299 trans = NULL;
300 }
301 }
302 if (ret && trans) {
303 btrfs_abort_transaction(trans, ret);
304 btrfs_end_transaction(trans);
305 }
306 if (!ret)
307 *trans_out = trans;
308
309 return ret;
310
311copy_to_page:
312 /*
313 * Release our path because we don't need it anymore and also because
314 * copy_inline_to_page() needs to reserve data and metadata, which may
315 * need to flush delalloc when we are low on available space and
316 * therefore cause a deadlock if writeback of an inline extent needs to
317 * write to the same leaf or an ordered extent completion needs to write
318 * to the same leaf.
319 */
320 btrfs_release_path(path);
321
322 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
323 inline_data, size, datal, comp_type);
324 goto out;
325}
326
327/*
328 * Clone a range from inode file to another.
329 *
330 * @src: Inode to clone from
331 * @inode: Inode to clone to
332 * @off: Offset within source to start clone from
333 * @olen: Original length, passed by user, of range to clone
334 * @olen_aligned: Block-aligned value of olen
335 * @destoff: Offset within @inode to start clone
336 * @no_time_update: Whether to update mtime/ctime on the target inode
337 */
338static int btrfs_clone(struct inode *src, struct inode *inode,
339 const u64 off, const u64 olen, const u64 olen_aligned,
340 const u64 destoff, int no_time_update)
341{
342 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
343 struct btrfs_path *path = NULL;
344 struct extent_buffer *leaf;
345 struct btrfs_trans_handle *trans;
346 char *buf = NULL;
347 struct btrfs_key key;
348 u32 nritems;
349 int slot;
350 int ret;
351 const u64 len = olen_aligned;
352 u64 last_dest_end = destoff;
353 u64 prev_extent_end = off;
354
355 ret = -ENOMEM;
356 buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
357 if (!buf)
358 return ret;
359
360 path = btrfs_alloc_path();
361 if (!path) {
362 kvfree(buf);
363 return ret;
364 }
365
366 path->reada = READA_FORWARD;
367 /* Clone data */
368 key.objectid = btrfs_ino(BTRFS_I(src));
369 key.type = BTRFS_EXTENT_DATA_KEY;
370 key.offset = off;
371
372 while (1) {
373 struct btrfs_file_extent_item *extent;
374 u64 extent_gen;
375 int type;
376 u32 size;
377 struct btrfs_key new_key;
378 u64 disko = 0, diskl = 0;
379 u64 datao = 0, datal = 0;
380 u8 comp;
381 u64 drop_start;
382
383 /* Note the key will change type as we walk through the tree */
384 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
385 0, 0);
386 if (ret < 0)
387 goto out;
388 /*
389 * First search, if no extent item that starts at offset off was
390 * found but the previous item is an extent item, it's possible
391 * it might overlap our target range, therefore process it.
392 */
393 if (key.offset == off && ret > 0 && path->slots[0] > 0) {
394 btrfs_item_key_to_cpu(path->nodes[0], &key,
395 path->slots[0] - 1);
396 if (key.type == BTRFS_EXTENT_DATA_KEY)
397 path->slots[0]--;
398 }
399
400 nritems = btrfs_header_nritems(path->nodes[0]);
401process_slot:
402 if (path->slots[0] >= nritems) {
403 ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
404 if (ret < 0)
405 goto out;
406 if (ret > 0)
407 break;
408 nritems = btrfs_header_nritems(path->nodes[0]);
409 }
410 leaf = path->nodes[0];
411 slot = path->slots[0];
412
413 btrfs_item_key_to_cpu(leaf, &key, slot);
414 if (key.type > BTRFS_EXTENT_DATA_KEY ||
415 key.objectid != btrfs_ino(BTRFS_I(src)))
416 break;
417
418 ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
419
420 extent = btrfs_item_ptr(leaf, slot,
421 struct btrfs_file_extent_item);
422 extent_gen = btrfs_file_extent_generation(leaf, extent);
423 comp = btrfs_file_extent_compression(leaf, extent);
424 type = btrfs_file_extent_type(leaf, extent);
425 if (type == BTRFS_FILE_EXTENT_REG ||
426 type == BTRFS_FILE_EXTENT_PREALLOC) {
427 disko = btrfs_file_extent_disk_bytenr(leaf, extent);
428 diskl = btrfs_file_extent_disk_num_bytes(leaf, extent);
429 datao = btrfs_file_extent_offset(leaf, extent);
430 datal = btrfs_file_extent_num_bytes(leaf, extent);
431 } else if (type == BTRFS_FILE_EXTENT_INLINE) {
432 /* Take upper bound, may be compressed */
433 datal = btrfs_file_extent_ram_bytes(leaf, extent);
434 }
435
436 /*
437 * The first search might have left us at an extent item that
438 * ends before our target range's start, can happen if we have
439 * holes and NO_HOLES feature enabled.
440 *
441 * Subsequent searches may leave us on a file range we have
442 * processed before - this happens due to a race with ordered
443 * extent completion for a file range that is outside our source
444 * range, but that range was part of a file extent item that
445 * also covered a leading part of our source range.
446 */
447 if (key.offset + datal <= prev_extent_end) {
448 path->slots[0]++;
449 goto process_slot;
450 } else if (key.offset >= off + len) {
451 break;
452 }
453
454 prev_extent_end = key.offset + datal;
455 size = btrfs_item_size(leaf, slot);
456 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot),
457 size);
458
459 btrfs_release_path(path);
460
461 memcpy(&new_key, &key, sizeof(new_key));
462 new_key.objectid = btrfs_ino(BTRFS_I(inode));
463 if (off <= key.offset)
464 new_key.offset = key.offset + destoff - off;
465 else
466 new_key.offset = destoff;
467
468 /*
469 * Deal with a hole that doesn't have an extent item that
470 * represents it (NO_HOLES feature enabled).
471 * This hole is either in the middle of the cloning range or at
472 * the beginning (fully overlaps it or partially overlaps it).
473 */
474 if (new_key.offset != last_dest_end)
475 drop_start = last_dest_end;
476 else
477 drop_start = new_key.offset;
478
479 if (type == BTRFS_FILE_EXTENT_REG ||
480 type == BTRFS_FILE_EXTENT_PREALLOC) {
481 struct btrfs_replace_extent_info clone_info;
482
483 /*
484 * a | --- range to clone ---| b
485 * | ------------- extent ------------- |
486 */
487
488 /* Subtract range b */
489 if (key.offset + datal > off + len)
490 datal = off + len - key.offset;
491
492 /* Subtract range a */
493 if (off > key.offset) {
494 datao += off - key.offset;
495 datal -= off - key.offset;
496 }
497
498 clone_info.disk_offset = disko;
499 clone_info.disk_len = diskl;
500 clone_info.data_offset = datao;
501 clone_info.data_len = datal;
502 clone_info.file_offset = new_key.offset;
503 clone_info.extent_buf = buf;
504 clone_info.is_new_extent = false;
505 clone_info.update_times = !no_time_update;
506 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
507 drop_start, new_key.offset + datal - 1,
508 &clone_info, &trans);
509 if (ret)
510 goto out;
511 } else {
512 ASSERT(type == BTRFS_FILE_EXTENT_INLINE);
513 /*
514 * Inline extents always have to start at file offset 0
515 * and can never be bigger then the sector size. We can
516 * never clone only parts of an inline extent, since all
517 * reflink operations must start at a sector size aligned
518 * offset, and the length must be aligned too or end at
519 * the i_size (which implies the whole inlined data).
520 */
521 ASSERT(key.offset == 0);
522 ASSERT(datal <= fs_info->sectorsize);
523 if (WARN_ON(type != BTRFS_FILE_EXTENT_INLINE) ||
524 WARN_ON(key.offset != 0) ||
525 WARN_ON(datal > fs_info->sectorsize)) {
526 ret = -EUCLEAN;
527 goto out;
528 }
529
530 ret = clone_copy_inline_extent(inode, path, &new_key,
531 drop_start, datal, size,
532 comp, buf, &trans);
533 if (ret)
534 goto out;
535 }
536
537 btrfs_release_path(path);
538
539 /*
540 * Whenever we share an extent we update the last_reflink_trans
541 * of each inode to the current transaction. This is needed to
542 * make sure fsync does not log multiple checksum items with
543 * overlapping ranges (because some extent items might refer
544 * only to sections of the original extent). For the destination
545 * inode we do this regardless of the generation of the extents
546 * or even if they are inline extents or explicit holes, to make
547 * sure a full fsync does not skip them. For the source inode,
548 * we only need to update last_reflink_trans in case it's a new
549 * extent that is not a hole or an inline extent, to deal with
550 * the checksums problem on fsync.
551 */
552 if (extent_gen == trans->transid && disko > 0)
553 BTRFS_I(src)->last_reflink_trans = trans->transid;
554
555 BTRFS_I(inode)->last_reflink_trans = trans->transid;
556
557 last_dest_end = ALIGN(new_key.offset + datal,
558 fs_info->sectorsize);
559 ret = clone_finish_inode_update(trans, inode, last_dest_end,
560 destoff, olen, no_time_update);
561 if (ret)
562 goto out;
563 if (new_key.offset + datal >= destoff + len)
564 break;
565
566 btrfs_release_path(path);
567 key.offset = prev_extent_end;
568
569 if (fatal_signal_pending(current)) {
570 ret = -EINTR;
571 goto out;
572 }
573
574 cond_resched();
575 }
576 ret = 0;
577
578 if (last_dest_end < destoff + len) {
579 /*
580 * We have an implicit hole that fully or partially overlaps our
581 * cloning range at its end. This means that we either have the
582 * NO_HOLES feature enabled or the implicit hole happened due to
583 * mixing buffered and direct IO writes against this file.
584 */
585 btrfs_release_path(path);
586
587 /*
588 * When using NO_HOLES and we are cloning a range that covers
589 * only a hole (no extents) into a range beyond the current
590 * i_size, punching a hole in the target range will not create
591 * an extent map defining a hole, because the range starts at or
592 * beyond current i_size. If the file previously had an i_size
593 * greater than the new i_size set by this clone operation, we
594 * need to make sure the next fsync is a full fsync, so that it
595 * detects and logs a hole covering a range from the current
596 * i_size to the new i_size. If the clone range covers extents,
597 * besides a hole, then we know the full sync flag was already
598 * set by previous calls to btrfs_replace_file_extents() that
599 * replaced file extent items.
600 */
601 if (last_dest_end >= i_size_read(inode))
602 btrfs_set_inode_full_sync(BTRFS_I(inode));
603
604 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
605 last_dest_end, destoff + len - 1, NULL, &trans);
606 if (ret)
607 goto out;
608
609 ret = clone_finish_inode_update(trans, inode, destoff + len,
610 destoff, olen, no_time_update);
611 }
612
613out:
614 btrfs_free_path(path);
615 kvfree(buf);
616 clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &BTRFS_I(inode)->runtime_flags);
617
618 return ret;
619}
620
621static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
622 struct inode *inode2, u64 loff2, u64 len)
623{
624 unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1, NULL);
625 unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1, NULL);
626}
627
628static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
629 struct inode *inode2, u64 loff2, u64 len)
630{
631 u64 range1_end = loff1 + len - 1;
632 u64 range2_end = loff2 + len - 1;
633
634 if (inode1 < inode2) {
635 swap(inode1, inode2);
636 swap(loff1, loff2);
637 swap(range1_end, range2_end);
638 } else if (inode1 == inode2 && loff2 < loff1) {
639 swap(loff1, loff2);
640 swap(range1_end, range2_end);
641 }
642
643 lock_extent(&BTRFS_I(inode1)->io_tree, loff1, range1_end, NULL);
644 lock_extent(&BTRFS_I(inode2)->io_tree, loff2, range2_end, NULL);
645
646 btrfs_assert_inode_range_clean(BTRFS_I(inode1), loff1, range1_end);
647 btrfs_assert_inode_range_clean(BTRFS_I(inode2), loff2, range2_end);
648}
649
650static void btrfs_double_mmap_lock(struct inode *inode1, struct inode *inode2)
651{
652 if (inode1 < inode2)
653 swap(inode1, inode2);
654 down_write(&BTRFS_I(inode1)->i_mmap_lock);
655 down_write_nested(&BTRFS_I(inode2)->i_mmap_lock, SINGLE_DEPTH_NESTING);
656}
657
658static void btrfs_double_mmap_unlock(struct inode *inode1, struct inode *inode2)
659{
660 up_write(&BTRFS_I(inode1)->i_mmap_lock);
661 up_write(&BTRFS_I(inode2)->i_mmap_lock);
662}
663
664static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len,
665 struct inode *dst, u64 dst_loff)
666{
667 struct btrfs_fs_info *fs_info = BTRFS_I(src)->root->fs_info;
668 const u64 bs = fs_info->sb->s_blocksize;
669 int ret;
670
671 /*
672 * Lock destination range to serialize with concurrent readahead() and
673 * source range to serialize with relocation.
674 */
675 btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
676 ret = btrfs_clone(src, dst, loff, len, ALIGN(len, bs), dst_loff, 1);
677 btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
678
679 btrfs_btree_balance_dirty(fs_info);
680
681 return ret;
682}
683
684static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
685 struct inode *dst, u64 dst_loff)
686{
687 int ret = 0;
688 u64 i, tail_len, chunk_count;
689 struct btrfs_root *root_dst = BTRFS_I(dst)->root;
690
691 spin_lock(&root_dst->root_item_lock);
692 if (root_dst->send_in_progress) {
693 btrfs_warn_rl(root_dst->fs_info,
694"cannot deduplicate to root %llu while send operations are using it (%d in progress)",
695 root_dst->root_key.objectid,
696 root_dst->send_in_progress);
697 spin_unlock(&root_dst->root_item_lock);
698 return -EAGAIN;
699 }
700 root_dst->dedupe_in_progress++;
701 spin_unlock(&root_dst->root_item_lock);
702
703 tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
704 chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
705
706 for (i = 0; i < chunk_count; i++) {
707 ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,
708 dst, dst_loff);
709 if (ret)
710 goto out;
711
712 loff += BTRFS_MAX_DEDUPE_LEN;
713 dst_loff += BTRFS_MAX_DEDUPE_LEN;
714 }
715
716 if (tail_len > 0)
717 ret = btrfs_extent_same_range(src, loff, tail_len, dst, dst_loff);
718out:
719 spin_lock(&root_dst->root_item_lock);
720 root_dst->dedupe_in_progress--;
721 spin_unlock(&root_dst->root_item_lock);
722
723 return ret;
724}
725
726static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
727 u64 off, u64 olen, u64 destoff)
728{
729 struct inode *inode = file_inode(file);
730 struct inode *src = file_inode(file_src);
731 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
732 int ret;
733 int wb_ret;
734 u64 len = olen;
735 u64 bs = fs_info->sb->s_blocksize;
736
737 /*
738 * VFS's generic_remap_file_range_prep() protects us from cloning the
739 * eof block into the middle of a file, which would result in corruption
740 * if the file size is not blocksize aligned. So we don't need to check
741 * for that case here.
742 */
743 if (off + len == src->i_size)
744 len = ALIGN(src->i_size, bs) - off;
745
746 if (destoff > inode->i_size) {
747 const u64 wb_start = ALIGN_DOWN(inode->i_size, bs);
748
749 ret = btrfs_cont_expand(BTRFS_I(inode), inode->i_size, destoff);
750 if (ret)
751 return ret;
752 /*
753 * We may have truncated the last block if the inode's size is
754 * not sector size aligned, so we need to wait for writeback to
755 * complete before proceeding further, otherwise we can race
756 * with cloning and attempt to increment a reference to an
757 * extent that no longer exists (writeback completed right after
758 * we found the previous extent covering eof and before we
759 * attempted to increment its reference count).
760 */
761 ret = btrfs_wait_ordered_range(inode, wb_start,
762 destoff - wb_start);
763 if (ret)
764 return ret;
765 }
766
767 /*
768 * Lock destination range to serialize with concurrent readahead() and
769 * source range to serialize with relocation.
770 */
771 btrfs_double_extent_lock(src, off, inode, destoff, len);
772 ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
773 btrfs_double_extent_unlock(src, off, inode, destoff, len);
774
775 /*
776 * We may have copied an inline extent into a page of the destination
777 * range, so wait for writeback to complete before truncating pages
778 * from the page cache. This is a rare case.
779 */
780 wb_ret = btrfs_wait_ordered_range(inode, destoff, len);
781 ret = ret ? ret : wb_ret;
782 /*
783 * Truncate page cache pages so that future reads will see the cloned
784 * data immediately and not the previous data.
785 */
786 truncate_inode_pages_range(&inode->i_data,
787 round_down(destoff, PAGE_SIZE),
788 round_up(destoff + len, PAGE_SIZE) - 1);
789
790 btrfs_btree_balance_dirty(fs_info);
791
792 return ret;
793}
794
795static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in,
796 struct file *file_out, loff_t pos_out,
797 loff_t *len, unsigned int remap_flags)
798{
799 struct inode *inode_in = file_inode(file_in);
800 struct inode *inode_out = file_inode(file_out);
801 u64 bs = BTRFS_I(inode_out)->root->fs_info->sb->s_blocksize;
802 u64 wb_len;
803 int ret;
804
805 if (!(remap_flags & REMAP_FILE_DEDUP)) {
806 struct btrfs_root *root_out = BTRFS_I(inode_out)->root;
807
808 if (btrfs_root_readonly(root_out))
809 return -EROFS;
810
811 ASSERT(inode_in->i_sb == inode_out->i_sb);
812 }
813
814 /* Don't make the dst file partly checksummed */
815 if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) !=
816 (BTRFS_I(inode_out)->flags & BTRFS_INODE_NODATASUM)) {
817 return -EINVAL;
818 }
819
820 /*
821 * Now that the inodes are locked, we need to start writeback ourselves
822 * and can not rely on the writeback from the VFS's generic helper
823 * generic_remap_file_range_prep() because:
824 *
825 * 1) For compression we must call filemap_fdatawrite_range() range
826 * twice (btrfs_fdatawrite_range() does it for us), and the generic
827 * helper only calls it once;
828 *
829 * 2) filemap_fdatawrite_range(), called by the generic helper only
830 * waits for the writeback to complete, i.e. for IO to be done, and
831 * not for the ordered extents to complete. We need to wait for them
832 * to complete so that new file extent items are in the fs tree.
833 */
834 if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP))
835 wb_len = ALIGN(inode_in->i_size, bs) - ALIGN_DOWN(pos_in, bs);
836 else
837 wb_len = ALIGN(*len, bs);
838
839 /*
840 * Workaround to make sure NOCOW buffered write reach disk as NOCOW.
841 *
842 * Btrfs' back references do not have a block level granularity, they
843 * work at the whole extent level.
844 * NOCOW buffered write without data space reserved may not be able
845 * to fall back to CoW due to lack of data space, thus could cause
846 * data loss.
847 *
848 * Here we take a shortcut by flushing the whole inode, so that all
849 * nocow write should reach disk as nocow before we increase the
850 * reference of the extent. We could do better by only flushing NOCOW
851 * data, but that needs extra accounting.
852 *
853 * Also we don't need to check ASYNC_EXTENT, as async extent will be
854 * CoWed anyway, not affecting nocow part.
855 */
856 ret = filemap_flush(inode_in->i_mapping);
857 if (ret < 0)
858 return ret;
859
860 ret = btrfs_wait_ordered_range(inode_in, ALIGN_DOWN(pos_in, bs),
861 wb_len);
862 if (ret < 0)
863 return ret;
864 ret = btrfs_wait_ordered_range(inode_out, ALIGN_DOWN(pos_out, bs),
865 wb_len);
866 if (ret < 0)
867 return ret;
868
869 return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
870 len, remap_flags);
871}
872
873static bool file_sync_write(const struct file *file)
874{
875 if (file->f_flags & (__O_SYNC | O_DSYNC))
876 return true;
877 if (IS_SYNC(file_inode(file)))
878 return true;
879
880 return false;
881}
882
883loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
884 struct file *dst_file, loff_t destoff, loff_t len,
885 unsigned int remap_flags)
886{
887 struct inode *src_inode = file_inode(src_file);
888 struct inode *dst_inode = file_inode(dst_file);
889 bool same_inode = dst_inode == src_inode;
890 int ret;
891
892 if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
893 return -EINVAL;
894
895 if (same_inode) {
896 btrfs_inode_lock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);
897 } else {
898 lock_two_nondirectories(src_inode, dst_inode);
899 btrfs_double_mmap_lock(src_inode, dst_inode);
900 }
901
902 ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff,
903 &len, remap_flags);
904 if (ret < 0 || len == 0)
905 goto out_unlock;
906
907 if (remap_flags & REMAP_FILE_DEDUP)
908 ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff);
909 else
910 ret = btrfs_clone_files(dst_file, src_file, off, len, destoff);
911
912out_unlock:
913 if (same_inode) {
914 btrfs_inode_unlock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);
915 } else {
916 btrfs_double_mmap_unlock(src_inode, dst_inode);
917 unlock_two_nondirectories(src_inode, dst_inode);
918 }
919
920 /*
921 * If either the source or the destination file was opened with O_SYNC,
922 * O_DSYNC or has the S_SYNC attribute, fsync both the destination and
923 * source files/ranges, so that after a successful return (0) followed
924 * by a power failure results in the reflinked data to be readable from
925 * both files/ranges.
926 */
927 if (ret == 0 && len > 0 &&
928 (file_sync_write(src_file) || file_sync_write(dst_file))) {
929 ret = btrfs_sync_file(src_file, off, off + len - 1, 0);
930 if (ret == 0)
931 ret = btrfs_sync_file(dst_file, destoff,
932 destoff + len - 1, 0);
933 }
934
935 return ret < 0 ? ret : len;
936}