1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/blkdev.h>
4 #include <linux/iversion.h>
5 #include "compression.h"
7 #include "delalloc-space.h"
9 #include "transaction.h"
12 #define BTRFS_MAX_DEDUPE_LEN SZ_16M
14 static int clone_finish_inode_update(struct btrfs_trans_handle
*trans
,
21 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
24 inode_inc_iversion(inode
);
26 inode
->i_mtime
= inode
->i_ctime
= current_time(inode
);
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.
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);
38 ret
= btrfs_update_inode(trans
, root
, BTRFS_I(inode
));
40 btrfs_abort_transaction(trans
, ret
);
41 btrfs_end_transaction(trans
);
44 ret
= btrfs_end_transaction(trans
);
49 static int copy_inline_to_page(struct btrfs_inode
*inode
,
50 const u64 file_offset
,
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
;
66 ASSERT(IS_ALIGNED(file_offset
, block_size
));
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.
74 ret
= btrfs_delalloc_reserve_space(inode
, &data_reserved
, file_offset
,
79 page
= find_or_create_page(mapping
, file_offset
>> PAGE_SHIFT
,
80 btrfs_alloc_write_mask(mapping
));
86 ret
= set_page_extent_mapped(page
);
90 clear_extent_bit(&inode
->io_tree
, file_offset
, range_end
,
91 EXTENT_DELALLOC
| EXTENT_DO_ACCOUNTING
| EXTENT_DEFRAG
,
93 ret
= btrfs_set_extent_delalloc(inode
, file_offset
, range_end
, 0, NULL
);
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.
108 set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH
, &inode
->runtime_flags
);
110 if (comp_type
== BTRFS_COMPRESS_NONE
) {
111 memcpy_to_page(page
, offset_in_page(file_offset
), data_start
,
113 flush_dcache_page(page
);
115 ret
= btrfs_decompress(comp_type
, data_start
, page
,
116 offset_in_page(file_offset
),
120 flush_dcache_page(page
);
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:
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"
133 * So what's in the range [500, 4095] corresponds to zeroes.
135 if (datal
< block_size
) {
136 memzero_page(page
, datal
, block_size
- datal
);
137 flush_dcache_page(page
);
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
);
149 btrfs_delalloc_release_space(inode
, data_reserved
, file_offset
,
151 btrfs_delalloc_release_extents(inode
, block_size
);
153 extent_changeset_free(data_reserved
);
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.
163 static int clone_copy_inline_extent(struct inode
*dst
,
164 struct btrfs_path
*path
,
165 struct btrfs_key
*new_key
,
166 const u64 drop_start
,
171 struct btrfs_trans_handle
**trans_out
)
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 };
180 struct btrfs_key key
;
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
);
188 key
.objectid
= btrfs_ino(BTRFS_I(dst
));
189 key
.type
= BTRFS_EXTENT_DATA_KEY
;
191 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
194 } else if (ret
> 0) {
195 if (path
->slots
[0] >= btrfs_header_nritems(path
->nodes
[0])) {
196 ret
= btrfs_next_leaf(root
, path
);
200 goto copy_inline_extent
;
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
) {
206 * There's an implicit hole at file offset 0, copy the
207 * inline extent's data to the page.
209 ASSERT(key
.offset
> 0);
212 } else if (i_size_read(dst
) <= datal
) {
213 struct btrfs_file_extent_item
*ei
;
215 ei
= btrfs_item_ptr(path
->nodes
[0], path
->slots
[0],
216 struct btrfs_file_extent_item
);
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.
222 if (btrfs_file_extent_type(path
->nodes
[0], ei
) ==
223 BTRFS_FILE_EXTENT_INLINE
)
224 goto copy_inline_extent
;
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.
234 if (i_size_read(dst
) > datal
) {
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.
245 * Release path before starting a new transaction so we don't hold locks
246 * that would confuse lockdep.
248 btrfs_release_path(path
);
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.
254 * 1 unit - adjusting old extent (we may have to split it)
255 * 1 unit - add new extent
256 * 1 unit - inode update
258 trans
= btrfs_start_transaction(root
, 3);
260 ret
= PTR_ERR(trans
);
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
);
271 ret
= btrfs_insert_empty_item(trans
, root
, path
, new_key
, size
);
275 write_extent_buffer(path
->nodes
[0], inline_data
,
276 btrfs_item_ptr_offset(path
->nodes
[0],
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
);
283 if (!ret
&& !trans
) {
285 * No transaction here means we copied the inline extent into a
286 * page of the destination inode.
288 * 1 unit to update inode item
290 trans
= btrfs_start_transaction(root
, 1);
292 ret
= PTR_ERR(trans
);
297 btrfs_abort_transaction(trans
, ret
);
298 btrfs_end_transaction(trans
);
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
314 btrfs_release_path(path
);
316 ret
= copy_inline_to_page(BTRFS_I(dst
), new_key
->offset
,
317 inline_data
, size
, datal
, comp_type
);
322 * btrfs_clone() - clone a range from inode file to another
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
332 static 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
)
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
;
341 struct btrfs_key key
;
345 const u64 len
= olen_aligned
;
346 u64 last_dest_end
= destoff
;
349 buf
= kvmalloc(fs_info
->nodesize
, GFP_KERNEL
);
353 path
= btrfs_alloc_path();
359 path
->reada
= READA_FORWARD
;
361 key
.objectid
= btrfs_ino(BTRFS_I(src
));
362 key
.type
= BTRFS_EXTENT_DATA_KEY
;
366 u64 next_key_min_offset
= key
.offset
+ 1;
367 struct btrfs_file_extent_item
*extent
;
371 struct btrfs_key new_key
;
372 u64 disko
= 0, diskl
= 0;
373 u64 datao
= 0, datal
= 0;
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
,
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.
387 if (key
.offset
== off
&& ret
> 0 && path
->slots
[0] > 0) {
388 btrfs_item_key_to_cpu(path
->nodes
[0], &key
,
390 if (key
.type
== BTRFS_EXTENT_DATA_KEY
)
394 nritems
= btrfs_header_nritems(path
->nodes
[0]);
396 if (path
->slots
[0] >= nritems
) {
397 ret
= btrfs_next_leaf(BTRFS_I(src
)->root
, path
);
402 nritems
= btrfs_header_nritems(path
->nodes
[0]);
404 leaf
= path
->nodes
[0];
405 slot
= path
->slots
[0];
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
)))
412 ASSERT(key
.type
== BTRFS_EXTENT_DATA_KEY
);
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
);
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.
435 if (key
.offset
+ datal
<= off
) {
438 } else if (key
.offset
>= off
+ len
) {
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
),
446 btrfs_release_path(path
);
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
;
453 new_key
.offset
= destoff
;
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).
461 if (new_key
.offset
!= last_dest_end
)
462 drop_start
= last_dest_end
;
464 drop_start
= new_key
.offset
;
466 if (type
== BTRFS_FILE_EXTENT_REG
||
467 type
== BTRFS_FILE_EXTENT_PREALLOC
) {
468 struct btrfs_replace_extent_info clone_info
;
471 * a | --- range to clone ---| b
472 * | ------------- extent ------------- |
475 /* Subtract range b */
476 if (key
.offset
+ datal
> off
+ len
)
477 datal
= off
+ len
- key
.offset
;
479 /* Subtract range a */
480 if (off
> key
.offset
) {
481 datao
+= off
- key
.offset
;
482 datal
-= off
- key
.offset
;
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
);
497 } else if (type
== BTRFS_FILE_EXTENT_INLINE
) {
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).
506 ASSERT(key
.offset
== 0);
507 ASSERT(datal
<= fs_info
->sectorsize
);
508 if (key
.offset
!= 0 || datal
> fs_info
->sectorsize
)
511 ret
= clone_copy_inline_extent(inode
, path
, &new_key
,
512 drop_start
, datal
, size
,
518 btrfs_release_path(path
);
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.
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
;
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
);
539 if (new_key
.offset
+ datal
>= destoff
+ len
)
542 btrfs_release_path(path
);
543 key
.offset
= next_key_min_offset
;
545 if (fatal_signal_pending(current
)) {
554 if (last_dest_end
< destoff
+ len
) {
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.
561 btrfs_release_path(path
);
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.
577 if (last_dest_end
>= i_size_read(inode
))
578 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC
,
579 &BTRFS_I(inode
)->runtime_flags
);
581 ret
= btrfs_replace_file_extents(BTRFS_I(inode
), path
,
582 last_dest_end
, destoff
+ len
- 1, NULL
, &trans
);
586 ret
= clone_finish_inode_update(trans
, inode
, destoff
+ len
,
587 destoff
, olen
, no_time_update
);
591 btrfs_free_path(path
);
593 clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH
, &BTRFS_I(inode
)->runtime_flags
);
598 static void btrfs_double_extent_unlock(struct inode
*inode1
, u64 loff1
,
599 struct inode
*inode2
, u64 loff2
, u64 len
)
601 unlock_extent(&BTRFS_I(inode1
)->io_tree
, loff1
, loff1
+ len
- 1);
602 unlock_extent(&BTRFS_I(inode2
)->io_tree
, loff2
, loff2
+ len
- 1);
605 static void btrfs_double_extent_lock(struct inode
*inode1
, u64 loff1
,
606 struct inode
*inode2
, u64 loff2
, u64 len
)
608 if (inode1
< inode2
) {
609 swap(inode1
, inode2
);
611 } else if (inode1
== inode2
&& loff2
< loff1
) {
614 lock_extent(&BTRFS_I(inode1
)->io_tree
, loff1
, loff1
+ len
- 1);
615 lock_extent(&BTRFS_I(inode2
)->io_tree
, loff2
, loff2
+ len
- 1);
618 static void btrfs_double_mmap_lock(struct inode
*inode1
, struct inode
*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
);
626 static void btrfs_double_mmap_unlock(struct inode
*inode1
, struct inode
*inode2
)
628 up_write(&BTRFS_I(inode1
)->i_mmap_lock
);
629 up_write(&BTRFS_I(inode2
)->i_mmap_lock
);
632 static int btrfs_extent_same_range(struct inode
*src
, u64 loff
, u64 len
,
633 struct inode
*dst
, u64 dst_loff
)
635 const u64 bs
= BTRFS_I(src
)->root
->fs_info
->sb
->s_blocksize
;
639 * Lock destination range to serialize with concurrent readpages() and
640 * source range to serialize with relocation.
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
);
649 static int btrfs_extent_same(struct inode
*src
, u64 loff
, u64 olen
,
650 struct inode
*dst
, u64 dst_loff
)
653 u64 i
, tail_len
, chunk_count
;
654 struct btrfs_root
*root_dst
= BTRFS_I(dst
)->root
;
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
);
665 root_dst
->dedupe_in_progress
++;
666 spin_unlock(&root_dst
->root_item_lock
);
668 tail_len
= olen
% BTRFS_MAX_DEDUPE_LEN
;
669 chunk_count
= div_u64(olen
, BTRFS_MAX_DEDUPE_LEN
);
671 for (i
= 0; i
< chunk_count
; i
++) {
672 ret
= btrfs_extent_same_range(src
, loff
, BTRFS_MAX_DEDUPE_LEN
,
677 loff
+= BTRFS_MAX_DEDUPE_LEN
;
678 dst_loff
+= BTRFS_MAX_DEDUPE_LEN
;
682 ret
= btrfs_extent_same_range(src
, loff
, tail_len
, dst
, dst_loff
);
684 spin_lock(&root_dst
->root_item_lock
);
685 root_dst
->dedupe_in_progress
--;
686 spin_unlock(&root_dst
->root_item_lock
);
691 static noinline
int btrfs_clone_files(struct file
*file
, struct file
*file_src
,
692 u64 off
, u64 olen
, u64 destoff
)
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
);
700 u64 bs
= fs_info
->sb
->s_blocksize
;
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.
708 if (off
+ len
== src
->i_size
)
709 len
= ALIGN(src
->i_size
, bs
) - off
;
711 if (destoff
> inode
->i_size
) {
712 const u64 wb_start
= ALIGN_DOWN(inode
->i_size
, bs
);
714 ret
= btrfs_cont_expand(BTRFS_I(inode
), inode
->i_size
, destoff
);
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).
726 ret
= btrfs_wait_ordered_range(inode
, wb_start
,
733 * Lock destination range to serialize with concurrent readpages() and
734 * source range to serialize with relocation.
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
);
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.
745 wb_ret
= btrfs_wait_ordered_range(inode
, destoff
, len
);
746 ret
= ret
? ret
: wb_ret
;
748 * Truncate page cache pages so that future reads will see the cloned
749 * data immediately and not the previous data.
751 truncate_inode_pages_range(&inode
->i_data
,
752 round_down(destoff
, PAGE_SIZE
),
753 round_up(destoff
+ len
, PAGE_SIZE
) - 1);
758 static 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
)
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
;
769 if (!(remap_flags
& REMAP_FILE_DEDUP
)) {
770 struct btrfs_root
*root_out
= BTRFS_I(inode_out
)->root
;
772 if (btrfs_root_readonly(root_out
))
775 if (file_in
->f_path
.mnt
!= file_out
->f_path
.mnt
||
776 inode_in
->i_sb
!= inode_out
->i_sb
)
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
)) {
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:
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;
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.
800 if (*len
== 0 && !(remap_flags
& REMAP_FILE_DEDUP
))
801 wb_len
= ALIGN(inode_in
->i_size
, bs
) - ALIGN_DOWN(pos_in
, bs
);
803 wb_len
= ALIGN(*len
, bs
);
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).
810 inode_dio_wait(inode_in
);
812 inode_dio_wait(inode_out
);
815 * Workaround to make sure NOCOW buffered write reach disk as NOCOW.
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
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.
828 * Also we don't need to check ASYNC_EXTENT, as async extent will be
829 * CoWed anyway, not affecting nocow part.
831 ret
= filemap_flush(inode_in
->i_mapping
);
835 ret
= btrfs_wait_ordered_range(inode_in
, ALIGN_DOWN(pos_in
, bs
),
839 ret
= btrfs_wait_ordered_range(inode_out
, ALIGN_DOWN(pos_out
, bs
),
844 return generic_remap_file_range_prep(file_in
, pos_in
, file_out
, pos_out
,
848 static bool file_sync_write(const struct file
*file
)
850 if (file
->f_flags
& (__O_SYNC
| O_DSYNC
))
852 if (IS_SYNC(file_inode(file
)))
858 loff_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
)
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
;
867 if (remap_flags
& ~(REMAP_FILE_DEDUP
| REMAP_FILE_ADVISORY
))
871 btrfs_inode_lock(src_inode
, BTRFS_ILOCK_MMAP
);
873 lock_two_nondirectories(src_inode
, dst_inode
);
874 btrfs_double_mmap_lock(src_inode
, dst_inode
);
877 ret
= btrfs_remap_file_range_prep(src_file
, off
, dst_file
, destoff
,
879 if (ret
< 0 || len
== 0)
882 if (remap_flags
& REMAP_FILE_DEDUP
)
883 ret
= btrfs_extent_same(src_inode
, off
, len
, dst_inode
, destoff
);
885 ret
= btrfs_clone_files(dst_file
, src_file
, off
, len
, destoff
);
889 btrfs_inode_unlock(src_inode
, BTRFS_ILOCK_MMAP
);
891 btrfs_double_mmap_unlock(src_inode
, dst_inode
);
892 unlock_two_nondirectories(src_inode
, dst_inode
);
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
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);
906 ret
= btrfs_sync_file(dst_file
, destoff
,
907 destoff
+ len
- 1, 0);
910 return ret
< 0 ? ret
: len
;