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1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/blkdev.h>
4#include <linux/iversion.h>
5#include "compression.h"
6#include "ctree.h"
7#include "delalloc-space.h"
8#include "reflink.h"
9#include "transaction.h"
10#include "subpage.h"
11
12#define BTRFS_MAX_DEDUPE_LEN SZ_16M
13
14static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
15 struct inode *inode,
16 u64 endoff,
17 const u64 destoff,
18 const u64 olen,
19 int no_time_update)
20{
21 struct btrfs_root *root = BTRFS_I(inode)->root;
22 int ret;
23
24 inode_inc_iversion(inode);
25 if (!no_time_update)
26 inode->i_mtime = inode->i_ctime = current_time(inode);
27 /*
28 * We round up to the block size at eof when determining which
29 * extents to clone above, but shouldn't round up the file size.
30 */
31 if (endoff > destoff + olen)
32 endoff = destoff + olen;
33 if (endoff > inode->i_size) {
34 i_size_write(inode, endoff);
35 btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
36 }
37
38 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
39 if (ret) {
40 btrfs_abort_transaction(trans, ret);
41 btrfs_end_transaction(trans);
42 goto out;
43 }
44 ret = btrfs_end_transaction(trans);
45out:
46 return ret;
47}
48
49static int copy_inline_to_page(struct btrfs_inode *inode,
50 const u64 file_offset,
51 char *inline_data,
52 const u64 size,
53 const u64 datal,
54 const u8 comp_type)
55{
56 struct btrfs_fs_info *fs_info = inode->root->fs_info;
57 const u32 block_size = fs_info->sectorsize;
58 const u64 range_end = file_offset + block_size - 1;
59 const size_t inline_size = size - btrfs_file_extent_calc_inline_size(0);
60 char *data_start = inline_data + btrfs_file_extent_calc_inline_size(0);
61 struct extent_changeset *data_reserved = NULL;
62 struct page *page = NULL;
63 struct address_space *mapping = inode->vfs_inode.i_mapping;
64 int ret;
65
66 ASSERT(IS_ALIGNED(file_offset, block_size));
67
68 /*
69 * We have flushed and locked the ranges of the source and destination
70 * inodes, we also have locked the inodes, so we are safe to do a
71 * reservation here. Also we must not do the reservation while holding
72 * a transaction open, otherwise we would deadlock.
73 */
74 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, file_offset,
75 block_size);
76 if (ret)
77 goto out;
78
79 page = find_or_create_page(mapping, file_offset >> PAGE_SHIFT,
80 btrfs_alloc_write_mask(mapping));
81 if (!page) {
82 ret = -ENOMEM;
83 goto out_unlock;
84 }
85
86 ret = set_page_extent_mapped(page);
87 if (ret < 0)
88 goto out_unlock;
89
90 clear_extent_bit(&inode->io_tree, file_offset, range_end,
91 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
92 0, 0, NULL);
93 ret = btrfs_set_extent_delalloc(inode, file_offset, range_end, 0, NULL);
94 if (ret)
95 goto out_unlock;
96
97 /*
98 * After dirtying the page our caller will need to start a transaction,
99 * and if we are low on metadata free space, that can cause flushing of
100 * delalloc for all inodes in order to get metadata space released.
101 * However we are holding the range locked for the whole duration of
102 * the clone/dedupe operation, so we may deadlock if that happens and no
103 * other task releases enough space. So mark this inode as not being
104 * possible to flush to avoid such deadlock. We will clear that flag
105 * when we finish cloning all extents, since a transaction is started
106 * after finding each extent to clone.
107 */
108 set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags);
109
110 if (comp_type == BTRFS_COMPRESS_NONE) {
111 memcpy_to_page(page, offset_in_page(file_offset), data_start,
112 datal);
113 flush_dcache_page(page);
114 } else {
115 ret = btrfs_decompress(comp_type, data_start, page,
116 offset_in_page(file_offset),
117 inline_size, datal);
118 if (ret)
119 goto out_unlock;
120 flush_dcache_page(page);
121 }
122
123 /*
124 * If our inline data is smaller then the block/page size, then the
125 * remaining of the block/page is equivalent to zeroes. We had something
126 * like the following done:
127 *
128 * $ xfs_io -f -c "pwrite -S 0xab 0 500" file
129 * $ sync # (or fsync)
130 * $ xfs_io -c "falloc 0 4K" file
131 * $ xfs_io -c "pwrite -S 0xcd 4K 4K"
132 *
133 * So what's in the range [500, 4095] corresponds to zeroes.
134 */
135 if (datal < block_size) {
136 memzero_page(page, datal, block_size - datal);
137 flush_dcache_page(page);
138 }
139
140 btrfs_page_set_uptodate(fs_info, page, file_offset, block_size);
141 ClearPageChecked(page);
142 btrfs_page_set_dirty(fs_info, page, file_offset, block_size);
143out_unlock:
144 if (page) {
145 unlock_page(page);
146 put_page(page);
147 }
148 if (ret)
149 btrfs_delalloc_release_space(inode, data_reserved, file_offset,
150 block_size, true);
151 btrfs_delalloc_release_extents(inode, block_size);
152out:
153 extent_changeset_free(data_reserved);
154
155 return ret;
156}
157
158/*
159 * Deal with cloning of inline extents. We try to copy the inline extent from
160 * the source inode to destination inode when possible. When not possible we
161 * copy the inline extent's data into the respective page of the inode.
162 */
163static int clone_copy_inline_extent(struct inode *dst,
164 struct btrfs_path *path,
165 struct btrfs_key *new_key,
166 const u64 drop_start,
167 const u64 datal,
168 const u64 size,
169 const u8 comp_type,
170 char *inline_data,
171 struct btrfs_trans_handle **trans_out)
172{
173 struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb);
174 struct btrfs_root *root = BTRFS_I(dst)->root;
175 const u64 aligned_end = ALIGN(new_key->offset + datal,
176 fs_info->sectorsize);
177 struct btrfs_trans_handle *trans = NULL;
178 struct btrfs_drop_extents_args drop_args = { 0 };
179 int ret;
180 struct btrfs_key key;
181
182 if (new_key->offset > 0) {
183 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
184 inline_data, size, datal, comp_type);
185 goto out;
186 }
187
188 key.objectid = btrfs_ino(BTRFS_I(dst));
189 key.type = BTRFS_EXTENT_DATA_KEY;
190 key.offset = 0;
191 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
192 if (ret < 0) {
193 return ret;
194 } else if (ret > 0) {
195 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
196 ret = btrfs_next_leaf(root, path);
197 if (ret < 0)
198 return ret;
199 else if (ret > 0)
200 goto copy_inline_extent;
201 }
202 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
203 if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
204 key.type == BTRFS_EXTENT_DATA_KEY) {
205 /*
206 * There's an implicit hole at file offset 0, copy the
207 * inline extent's data to the page.
208 */
209 ASSERT(key.offset > 0);
210 goto copy_to_page;
211 }
212 } else if (i_size_read(dst) <= datal) {
213 struct btrfs_file_extent_item *ei;
214
215 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
216 struct btrfs_file_extent_item);
217 /*
218 * If it's an inline extent replace it with the source inline
219 * extent, otherwise copy the source inline extent data into
220 * the respective page at the destination inode.
221 */
222 if (btrfs_file_extent_type(path->nodes[0], ei) ==
223 BTRFS_FILE_EXTENT_INLINE)
224 goto copy_inline_extent;
225
226 goto copy_to_page;
227 }
228
229copy_inline_extent:
230 /*
231 * We have no extent items, or we have an extent at offset 0 which may
232 * or may not be inlined. All these cases are dealt the same way.
233 */
234 if (i_size_read(dst) > datal) {
235 /*
236 * At the destination offset 0 we have either a hole, a regular
237 * extent or an inline extent larger then the one we want to
238 * clone. Deal with all these cases by copying the inline extent
239 * data into the respective page at the destination inode.
240 */
241 goto copy_to_page;
242 }
243
244 /*
245 * Release path before starting a new transaction so we don't hold locks
246 * that would confuse lockdep.
247 */
248 btrfs_release_path(path);
249 /*
250 * If we end up here it means were copy the inline extent into a leaf
251 * of the destination inode. We know we will drop or adjust at most one
252 * extent item in the destination root.
253 *
254 * 1 unit - adjusting old extent (we may have to split it)
255 * 1 unit - add new extent
256 * 1 unit - inode update
257 */
258 trans = btrfs_start_transaction(root, 3);
259 if (IS_ERR(trans)) {
260 ret = PTR_ERR(trans);
261 trans = NULL;
262 goto out;
263 }
264 drop_args.path = path;
265 drop_args.start = drop_start;
266 drop_args.end = aligned_end;
267 drop_args.drop_cache = true;
268 ret = btrfs_drop_extents(trans, root, BTRFS_I(dst), &drop_args);
269 if (ret)
270 goto out;
271 ret = btrfs_insert_empty_item(trans, root, path, new_key, size);
272 if (ret)
273 goto out;
274
275 write_extent_buffer(path->nodes[0], inline_data,
276 btrfs_item_ptr_offset(path->nodes[0],
277 path->slots[0]),
278 size);
279 btrfs_update_inode_bytes(BTRFS_I(dst), datal, drop_args.bytes_found);
280 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(dst)->runtime_flags);
281 ret = btrfs_inode_set_file_extent_range(BTRFS_I(dst), 0, aligned_end);
282out:
283 if (!ret && !trans) {
284 /*
285 * No transaction here means we copied the inline extent into a
286 * page of the destination inode.
287 *
288 * 1 unit to update inode item
289 */
290 trans = btrfs_start_transaction(root, 1);
291 if (IS_ERR(trans)) {
292 ret = PTR_ERR(trans);
293 trans = NULL;
294 }
295 }
296 if (ret && trans) {
297 btrfs_abort_transaction(trans, ret);
298 btrfs_end_transaction(trans);
299 }
300 if (!ret)
301 *trans_out = trans;
302
303 return ret;
304
305copy_to_page:
306 /*
307 * Release our path because we don't need it anymore and also because
308 * copy_inline_to_page() needs to reserve data and metadata, which may
309 * need to flush delalloc when we are low on available space and
310 * therefore cause a deadlock if writeback of an inline extent needs to
311 * write to the same leaf or an ordered extent completion needs to write
312 * to the same leaf.
313 */
314 btrfs_release_path(path);
315
316 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
317 inline_data, size, datal, comp_type);
318 goto out;
319}
320
321/**
322 * btrfs_clone() - clone a range from inode file to another
323 *
324 * @src: Inode to clone from
325 * @inode: Inode to clone to
326 * @off: Offset within source to start clone from
327 * @olen: Original length, passed by user, of range to clone
328 * @olen_aligned: Block-aligned value of olen
329 * @destoff: Offset within @inode to start clone
330 * @no_time_update: Whether to update mtime/ctime on the target inode
331 */
332static int btrfs_clone(struct inode *src, struct inode *inode,
333 const u64 off, const u64 olen, const u64 olen_aligned,
334 const u64 destoff, int no_time_update)
335{
336 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
337 struct btrfs_path *path = NULL;
338 struct extent_buffer *leaf;
339 struct btrfs_trans_handle *trans;
340 char *buf = NULL;
341 struct btrfs_key key;
342 u32 nritems;
343 int slot;
344 int ret;
345 const u64 len = olen_aligned;
346 u64 last_dest_end = destoff;
347
348 ret = -ENOMEM;
349 buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
350 if (!buf)
351 return ret;
352
353 path = btrfs_alloc_path();
354 if (!path) {
355 kvfree(buf);
356 return ret;
357 }
358
359 path->reada = READA_FORWARD;
360 /* Clone data */
361 key.objectid = btrfs_ino(BTRFS_I(src));
362 key.type = BTRFS_EXTENT_DATA_KEY;
363 key.offset = off;
364
365 while (1) {
366 u64 next_key_min_offset = key.offset + 1;
367 struct btrfs_file_extent_item *extent;
368 u64 extent_gen;
369 int type;
370 u32 size;
371 struct btrfs_key new_key;
372 u64 disko = 0, diskl = 0;
373 u64 datao = 0, datal = 0;
374 u8 comp;
375 u64 drop_start;
376
377 /* Note the key will change type as we walk through the tree */
378 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
379 0, 0);
380 if (ret < 0)
381 goto out;
382 /*
383 * First search, if no extent item that starts at offset off was
384 * found but the previous item is an extent item, it's possible
385 * it might overlap our target range, therefore process it.
386 */
387 if (key.offset == off && ret > 0 && path->slots[0] > 0) {
388 btrfs_item_key_to_cpu(path->nodes[0], &key,
389 path->slots[0] - 1);
390 if (key.type == BTRFS_EXTENT_DATA_KEY)
391 path->slots[0]--;
392 }
393
394 nritems = btrfs_header_nritems(path->nodes[0]);
395process_slot:
396 if (path->slots[0] >= nritems) {
397 ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
398 if (ret < 0)
399 goto out;
400 if (ret > 0)
401 break;
402 nritems = btrfs_header_nritems(path->nodes[0]);
403 }
404 leaf = path->nodes[0];
405 slot = path->slots[0];
406
407 btrfs_item_key_to_cpu(leaf, &key, slot);
408 if (key.type > BTRFS_EXTENT_DATA_KEY ||
409 key.objectid != btrfs_ino(BTRFS_I(src)))
410 break;
411
412 ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
413
414 extent = btrfs_item_ptr(leaf, slot,
415 struct btrfs_file_extent_item);
416 extent_gen = btrfs_file_extent_generation(leaf, extent);
417 comp = btrfs_file_extent_compression(leaf, extent);
418 type = btrfs_file_extent_type(leaf, extent);
419 if (type == BTRFS_FILE_EXTENT_REG ||
420 type == BTRFS_FILE_EXTENT_PREALLOC) {
421 disko = btrfs_file_extent_disk_bytenr(leaf, extent);
422 diskl = btrfs_file_extent_disk_num_bytes(leaf, extent);
423 datao = btrfs_file_extent_offset(leaf, extent);
424 datal = btrfs_file_extent_num_bytes(leaf, extent);
425 } else if (type == BTRFS_FILE_EXTENT_INLINE) {
426 /* Take upper bound, may be compressed */
427 datal = btrfs_file_extent_ram_bytes(leaf, extent);
428 }
429
430 /*
431 * The first search might have left us at an extent item that
432 * ends before our target range's start, can happen if we have
433 * holes and NO_HOLES feature enabled.
434 */
435 if (key.offset + datal <= off) {
436 path->slots[0]++;
437 goto process_slot;
438 } else if (key.offset >= off + len) {
439 break;
440 }
441 next_key_min_offset = key.offset + datal;
442 size = btrfs_item_size_nr(leaf, slot);
443 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot),
444 size);
445
446 btrfs_release_path(path);
447
448 memcpy(&new_key, &key, sizeof(new_key));
449 new_key.objectid = btrfs_ino(BTRFS_I(inode));
450 if (off <= key.offset)
451 new_key.offset = key.offset + destoff - off;
452 else
453 new_key.offset = destoff;
454
455 /*
456 * Deal with a hole that doesn't have an extent item that
457 * represents it (NO_HOLES feature enabled).
458 * This hole is either in the middle of the cloning range or at
459 * the beginning (fully overlaps it or partially overlaps it).
460 */
461 if (new_key.offset != last_dest_end)
462 drop_start = last_dest_end;
463 else
464 drop_start = new_key.offset;
465
466 if (type == BTRFS_FILE_EXTENT_REG ||
467 type == BTRFS_FILE_EXTENT_PREALLOC) {
468 struct btrfs_replace_extent_info clone_info;
469
470 /*
471 * a | --- range to clone ---| b
472 * | ------------- extent ------------- |
473 */
474
475 /* Subtract range b */
476 if (key.offset + datal > off + len)
477 datal = off + len - key.offset;
478
479 /* Subtract range a */
480 if (off > key.offset) {
481 datao += off - key.offset;
482 datal -= off - key.offset;
483 }
484
485 clone_info.disk_offset = disko;
486 clone_info.disk_len = diskl;
487 clone_info.data_offset = datao;
488 clone_info.data_len = datal;
489 clone_info.file_offset = new_key.offset;
490 clone_info.extent_buf = buf;
491 clone_info.is_new_extent = false;
492 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
493 drop_start, new_key.offset + datal - 1,
494 &clone_info, &trans);
495 if (ret)
496 goto out;
497 } else if (type == BTRFS_FILE_EXTENT_INLINE) {
498 /*
499 * Inline extents always have to start at file offset 0
500 * and can never be bigger then the sector size. We can
501 * never clone only parts of an inline extent, since all
502 * reflink operations must start at a sector size aligned
503 * offset, and the length must be aligned too or end at
504 * the i_size (which implies the whole inlined data).
505 */
506 ASSERT(key.offset == 0);
507 ASSERT(datal <= fs_info->sectorsize);
508 if (key.offset != 0 || datal > fs_info->sectorsize)
509 return -EUCLEAN;
510
511 ret = clone_copy_inline_extent(inode, path, &new_key,
512 drop_start, datal, size,
513 comp, buf, &trans);
514 if (ret)
515 goto out;
516 }
517
518 btrfs_release_path(path);
519
520 /*
521 * If this is a new extent update the last_reflink_trans of both
522 * inodes. This is used by fsync to make sure it does not log
523 * multiple checksum items with overlapping ranges. For older
524 * extents we don't need to do it since inode logging skips the
525 * checksums for older extents. Also ignore holes and inline
526 * extents because they don't have checksums in the csum tree.
527 */
528 if (extent_gen == trans->transid && disko > 0) {
529 BTRFS_I(src)->last_reflink_trans = trans->transid;
530 BTRFS_I(inode)->last_reflink_trans = trans->transid;
531 }
532
533 last_dest_end = ALIGN(new_key.offset + datal,
534 fs_info->sectorsize);
535 ret = clone_finish_inode_update(trans, inode, last_dest_end,
536 destoff, olen, no_time_update);
537 if (ret)
538 goto out;
539 if (new_key.offset + datal >= destoff + len)
540 break;
541
542 btrfs_release_path(path);
543 key.offset = next_key_min_offset;
544
545 if (fatal_signal_pending(current)) {
546 ret = -EINTR;
547 goto out;
548 }
549
550 cond_resched();
551 }
552 ret = 0;
553
554 if (last_dest_end < destoff + len) {
555 /*
556 * We have an implicit hole that fully or partially overlaps our
557 * cloning range at its end. This means that we either have the
558 * NO_HOLES feature enabled or the implicit hole happened due to
559 * mixing buffered and direct IO writes against this file.
560 */
561 btrfs_release_path(path);
562
563 /*
564 * When using NO_HOLES and we are cloning a range that covers
565 * only a hole (no extents) into a range beyond the current
566 * i_size, punching a hole in the target range will not create
567 * an extent map defining a hole, because the range starts at or
568 * beyond current i_size. If the file previously had an i_size
569 * greater than the new i_size set by this clone operation, we
570 * need to make sure the next fsync is a full fsync, so that it
571 * detects and logs a hole covering a range from the current
572 * i_size to the new i_size. If the clone range covers extents,
573 * besides a hole, then we know the full sync flag was already
574 * set by previous calls to btrfs_replace_file_extents() that
575 * replaced file extent items.
576 */
577 if (last_dest_end >= i_size_read(inode))
578 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
579 &BTRFS_I(inode)->runtime_flags);
580
581 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
582 last_dest_end, destoff + len - 1, NULL, &trans);
583 if (ret)
584 goto out;
585
586 ret = clone_finish_inode_update(trans, inode, destoff + len,
587 destoff, olen, no_time_update);
588 }
589
590out:
591 btrfs_free_path(path);
592 kvfree(buf);
593 clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &BTRFS_I(inode)->runtime_flags);
594
595 return ret;
596}
597
598static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
599 struct inode *inode2, u64 loff2, u64 len)
600{
601 unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
602 unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
603}
604
605static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
606 struct inode *inode2, u64 loff2, u64 len)
607{
608 if (inode1 < inode2) {
609 swap(inode1, inode2);
610 swap(loff1, loff2);
611 } else if (inode1 == inode2 && loff2 < loff1) {
612 swap(loff1, loff2);
613 }
614 lock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
615 lock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
616}
617
618static void btrfs_double_mmap_lock(struct inode *inode1, struct inode *inode2)
619{
620 if (inode1 < inode2)
621 swap(inode1, inode2);
622 down_write(&BTRFS_I(inode1)->i_mmap_lock);
623 down_write_nested(&BTRFS_I(inode2)->i_mmap_lock, SINGLE_DEPTH_NESTING);
624}
625
626static void btrfs_double_mmap_unlock(struct inode *inode1, struct inode *inode2)
627{
628 up_write(&BTRFS_I(inode1)->i_mmap_lock);
629 up_write(&BTRFS_I(inode2)->i_mmap_lock);
630}
631
632static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len,
633 struct inode *dst, u64 dst_loff)
634{
635 const u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
636 int ret;
637
638 /*
639 * Lock destination range to serialize with concurrent readpages() and
640 * source range to serialize with relocation.
641 */
642 btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
643 ret = btrfs_clone(src, dst, loff, len, ALIGN(len, bs), dst_loff, 1);
644 btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
645
646 return ret;
647}
648
649static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
650 struct inode *dst, u64 dst_loff)
651{
652 int ret;
653 u64 i, tail_len, chunk_count;
654 struct btrfs_root *root_dst = BTRFS_I(dst)->root;
655
656 spin_lock(&root_dst->root_item_lock);
657 if (root_dst->send_in_progress) {
658 btrfs_warn_rl(root_dst->fs_info,
659"cannot deduplicate to root %llu while send operations are using it (%d in progress)",
660 root_dst->root_key.objectid,
661 root_dst->send_in_progress);
662 spin_unlock(&root_dst->root_item_lock);
663 return -EAGAIN;
664 }
665 root_dst->dedupe_in_progress++;
666 spin_unlock(&root_dst->root_item_lock);
667
668 tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
669 chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
670
671 for (i = 0; i < chunk_count; i++) {
672 ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,
673 dst, dst_loff);
674 if (ret)
675 goto out;
676
677 loff += BTRFS_MAX_DEDUPE_LEN;
678 dst_loff += BTRFS_MAX_DEDUPE_LEN;
679 }
680
681 if (tail_len > 0)
682 ret = btrfs_extent_same_range(src, loff, tail_len, dst, dst_loff);
683out:
684 spin_lock(&root_dst->root_item_lock);
685 root_dst->dedupe_in_progress--;
686 spin_unlock(&root_dst->root_item_lock);
687
688 return ret;
689}
690
691static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
692 u64 off, u64 olen, u64 destoff)
693{
694 struct inode *inode = file_inode(file);
695 struct inode *src = file_inode(file_src);
696 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
697 int ret;
698 int wb_ret;
699 u64 len = olen;
700 u64 bs = fs_info->sb->s_blocksize;
701
702 /*
703 * VFS's generic_remap_file_range_prep() protects us from cloning the
704 * eof block into the middle of a file, which would result in corruption
705 * if the file size is not blocksize aligned. So we don't need to check
706 * for that case here.
707 */
708 if (off + len == src->i_size)
709 len = ALIGN(src->i_size, bs) - off;
710
711 if (destoff > inode->i_size) {
712 const u64 wb_start = ALIGN_DOWN(inode->i_size, bs);
713
714 ret = btrfs_cont_expand(BTRFS_I(inode), inode->i_size, destoff);
715 if (ret)
716 return ret;
717 /*
718 * We may have truncated the last block if the inode's size is
719 * not sector size aligned, so we need to wait for writeback to
720 * complete before proceeding further, otherwise we can race
721 * with cloning and attempt to increment a reference to an
722 * extent that no longer exists (writeback completed right after
723 * we found the previous extent covering eof and before we
724 * attempted to increment its reference count).
725 */
726 ret = btrfs_wait_ordered_range(inode, wb_start,
727 destoff - wb_start);
728 if (ret)
729 return ret;
730 }
731
732 /*
733 * Lock destination range to serialize with concurrent readpages() and
734 * source range to serialize with relocation.
735 */
736 btrfs_double_extent_lock(src, off, inode, destoff, len);
737 ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
738 btrfs_double_extent_unlock(src, off, inode, destoff, len);
739
740 /*
741 * We may have copied an inline extent into a page of the destination
742 * range, so wait for writeback to complete before truncating pages
743 * from the page cache. This is a rare case.
744 */
745 wb_ret = btrfs_wait_ordered_range(inode, destoff, len);
746 ret = ret ? ret : wb_ret;
747 /*
748 * Truncate page cache pages so that future reads will see the cloned
749 * data immediately and not the previous data.
750 */
751 truncate_inode_pages_range(&inode->i_data,
752 round_down(destoff, PAGE_SIZE),
753 round_up(destoff + len, PAGE_SIZE) - 1);
754
755 return ret;
756}
757
758static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in,
759 struct file *file_out, loff_t pos_out,
760 loff_t *len, unsigned int remap_flags)
761{
762 struct inode *inode_in = file_inode(file_in);
763 struct inode *inode_out = file_inode(file_out);
764 u64 bs = BTRFS_I(inode_out)->root->fs_info->sb->s_blocksize;
765 bool same_inode = inode_out == inode_in;
766 u64 wb_len;
767 int ret;
768
769 if (!(remap_flags & REMAP_FILE_DEDUP)) {
770 struct btrfs_root *root_out = BTRFS_I(inode_out)->root;
771
772 if (btrfs_root_readonly(root_out))
773 return -EROFS;
774
775 if (file_in->f_path.mnt != file_out->f_path.mnt ||
776 inode_in->i_sb != inode_out->i_sb)
777 return -EXDEV;
778 }
779
780 /* Don't make the dst file partly checksummed */
781 if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) !=
782 (BTRFS_I(inode_out)->flags & BTRFS_INODE_NODATASUM)) {
783 return -EINVAL;
784 }
785
786 /*
787 * Now that the inodes are locked, we need to start writeback ourselves
788 * and can not rely on the writeback from the VFS's generic helper
789 * generic_remap_file_range_prep() because:
790 *
791 * 1) For compression we must call filemap_fdatawrite_range() range
792 * twice (btrfs_fdatawrite_range() does it for us), and the generic
793 * helper only calls it once;
794 *
795 * 2) filemap_fdatawrite_range(), called by the generic helper only
796 * waits for the writeback to complete, i.e. for IO to be done, and
797 * not for the ordered extents to complete. We need to wait for them
798 * to complete so that new file extent items are in the fs tree.
799 */
800 if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP))
801 wb_len = ALIGN(inode_in->i_size, bs) - ALIGN_DOWN(pos_in, bs);
802 else
803 wb_len = ALIGN(*len, bs);
804
805 /*
806 * Since we don't lock ranges, wait for ongoing lockless dio writes (as
807 * any in progress could create its ordered extents after we wait for
808 * existing ordered extents below).
809 */
810 inode_dio_wait(inode_in);
811 if (!same_inode)
812 inode_dio_wait(inode_out);
813
814 /*
815 * Workaround to make sure NOCOW buffered write reach disk as NOCOW.
816 *
817 * Btrfs' back references do not have a block level granularity, they
818 * work at the whole extent level.
819 * NOCOW buffered write without data space reserved may not be able
820 * to fall back to CoW due to lack of data space, thus could cause
821 * data loss.
822 *
823 * Here we take a shortcut by flushing the whole inode, so that all
824 * nocow write should reach disk as nocow before we increase the
825 * reference of the extent. We could do better by only flushing NOCOW
826 * data, but that needs extra accounting.
827 *
828 * Also we don't need to check ASYNC_EXTENT, as async extent will be
829 * CoWed anyway, not affecting nocow part.
830 */
831 ret = filemap_flush(inode_in->i_mapping);
832 if (ret < 0)
833 return ret;
834
835 ret = btrfs_wait_ordered_range(inode_in, ALIGN_DOWN(pos_in, bs),
836 wb_len);
837 if (ret < 0)
838 return ret;
839 ret = btrfs_wait_ordered_range(inode_out, ALIGN_DOWN(pos_out, bs),
840 wb_len);
841 if (ret < 0)
842 return ret;
843
844 return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
845 len, remap_flags);
846}
847
848static bool file_sync_write(const struct file *file)
849{
850 if (file->f_flags & (__O_SYNC | O_DSYNC))
851 return true;
852 if (IS_SYNC(file_inode(file)))
853 return true;
854
855 return false;
856}
857
858loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
859 struct file *dst_file, loff_t destoff, loff_t len,
860 unsigned int remap_flags)
861{
862 struct inode *src_inode = file_inode(src_file);
863 struct inode *dst_inode = file_inode(dst_file);
864 bool same_inode = dst_inode == src_inode;
865 int ret;
866
867 if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
868 return -EINVAL;
869
870 if (same_inode) {
871 btrfs_inode_lock(src_inode, BTRFS_ILOCK_MMAP);
872 } else {
873 lock_two_nondirectories(src_inode, dst_inode);
874 btrfs_double_mmap_lock(src_inode, dst_inode);
875 }
876
877 ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff,
878 &len, remap_flags);
879 if (ret < 0 || len == 0)
880 goto out_unlock;
881
882 if (remap_flags & REMAP_FILE_DEDUP)
883 ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff);
884 else
885 ret = btrfs_clone_files(dst_file, src_file, off, len, destoff);
886
887out_unlock:
888 if (same_inode) {
889 btrfs_inode_unlock(src_inode, BTRFS_ILOCK_MMAP);
890 } else {
891 btrfs_double_mmap_unlock(src_inode, dst_inode);
892 unlock_two_nondirectories(src_inode, dst_inode);
893 }
894
895 /*
896 * If either the source or the destination file was opened with O_SYNC,
897 * O_DSYNC or has the S_SYNC attribute, fsync both the destination and
898 * source files/ranges, so that after a successful return (0) followed
899 * by a power failure results in the reflinked data to be readable from
900 * both files/ranges.
901 */
902 if (ret == 0 && len > 0 &&
903 (file_sync_write(src_file) || file_sync_write(dst_file))) {
904 ret = btrfs_sync_file(src_file, off, off + len - 1, 0);
905 if (ret == 0)
906 ret = btrfs_sync_file(dst_file, destoff,
907 destoff + len - 1, 0);
908 }
909
910 return ret < 0 ? ret : len;
911}