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