Line data Source code
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 :
21 0 : static 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 0 : struct btrfs_root *root = BTRFS_I(inode)->root;
29 0 : int ret;
30 :
31 0 : inode_inc_iversion(inode);
32 0 : if (!no_time_update) {
33 0 : inode->i_mtime = current_time(inode);
34 0 : 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 0 : if (endoff > destoff + olen)
41 : endoff = destoff + olen;
42 0 : if (endoff > inode->i_size) {
43 0 : i_size_write(inode, endoff);
44 0 : btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
45 : }
46 :
47 0 : ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
48 0 : if (ret) {
49 0 : btrfs_abort_transaction(trans, ret);
50 0 : btrfs_end_transaction(trans);
51 0 : goto out;
52 : }
53 0 : ret = btrfs_end_transaction(trans);
54 0 : out:
55 0 : return ret;
56 : }
57 :
58 0 : static 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 0 : struct btrfs_fs_info *fs_info = inode->root->fs_info;
66 0 : const u32 block_size = fs_info->sectorsize;
67 0 : const u64 range_end = file_offset + block_size - 1;
68 0 : const size_t inline_size = size - btrfs_file_extent_calc_inline_size(0);
69 0 : char *data_start = inline_data + btrfs_file_extent_calc_inline_size(0);
70 0 : struct extent_changeset *data_reserved = NULL;
71 0 : struct page *page = NULL;
72 0 : struct address_space *mapping = inode->vfs_inode.i_mapping;
73 0 : int ret;
74 :
75 0 : 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 0 : ret = btrfs_delalloc_reserve_space(inode, &data_reserved, file_offset,
84 : block_size);
85 0 : if (ret)
86 0 : goto out;
87 :
88 0 : page = find_or_create_page(mapping, file_offset >> PAGE_SHIFT,
89 : btrfs_alloc_write_mask(mapping));
90 0 : if (!page) {
91 0 : ret = -ENOMEM;
92 0 : goto out_unlock;
93 : }
94 :
95 0 : ret = set_page_extent_mapped(page);
96 0 : if (ret < 0)
97 0 : goto out_unlock;
98 :
99 0 : clear_extent_bit(&inode->io_tree, file_offset, range_end,
100 : EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
101 : NULL);
102 0 : ret = btrfs_set_extent_delalloc(inode, file_offset, range_end, 0, NULL);
103 0 : if (ret)
104 0 : 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 0 : set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags);
118 :
119 0 : if (comp_type == BTRFS_COMPRESS_NONE) {
120 0 : memcpy_to_page(page, offset_in_page(file_offset), data_start,
121 : datal);
122 : } else {
123 0 : ret = btrfs_decompress(comp_type, data_start, page,
124 : offset_in_page(file_offset),
125 : inline_size, datal);
126 0 : if (ret)
127 0 : goto out_unlock;
128 0 : 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 0 : if (datal < block_size)
144 0 : memzero_page(page, datal, block_size - datal);
145 :
146 0 : btrfs_page_set_uptodate(fs_info, page, file_offset, block_size);
147 0 : btrfs_page_clear_checked(fs_info, page, file_offset, block_size);
148 0 : btrfs_page_set_dirty(fs_info, page, file_offset, block_size);
149 0 : out_unlock:
150 0 : if (page) {
151 0 : unlock_page(page);
152 0 : put_page(page);
153 : }
154 0 : if (ret)
155 0 : btrfs_delalloc_release_space(inode, data_reserved, file_offset,
156 : block_size, true);
157 0 : btrfs_delalloc_release_extents(inode, block_size);
158 0 : out:
159 0 : extent_changeset_free(data_reserved);
160 :
161 0 : 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 : */
169 0 : static 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 0 : struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb);
180 0 : struct btrfs_root *root = BTRFS_I(dst)->root;
181 0 : const u64 aligned_end = ALIGN(new_key->offset + datal,
182 : fs_info->sectorsize);
183 0 : struct btrfs_trans_handle *trans = NULL;
184 0 : struct btrfs_drop_extents_args drop_args = { 0 };
185 0 : int ret;
186 0 : struct btrfs_key key;
187 :
188 0 : if (new_key->offset > 0) {
189 0 : ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
190 : inline_data, size, datal, comp_type);
191 0 : goto out;
192 : }
193 :
194 0 : key.objectid = btrfs_ino(BTRFS_I(dst));
195 0 : key.type = BTRFS_EXTENT_DATA_KEY;
196 0 : key.offset = 0;
197 0 : ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
198 0 : if (ret < 0) {
199 : return ret;
200 0 : } else if (ret > 0) {
201 0 : if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
202 0 : ret = btrfs_next_leaf(root, path);
203 0 : if (ret < 0)
204 : return ret;
205 0 : else if (ret > 0)
206 0 : goto copy_inline_extent;
207 : }
208 0 : btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
209 0 : if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
210 0 : 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 0 : ASSERT(key.offset > 0);
216 0 : goto copy_to_page;
217 : }
218 0 : } else if (i_size_read(dst) <= datal) {
219 0 : struct btrfs_file_extent_item *ei;
220 :
221 0 : 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 0 : if (btrfs_file_extent_type(path->nodes[0], ei) ==
229 : BTRFS_FILE_EXTENT_INLINE)
230 0 : goto copy_inline_extent;
231 :
232 0 : goto copy_to_page;
233 : }
234 :
235 0 : copy_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 0 : 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 0 : 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 0 : 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 0 : trans = btrfs_start_transaction(root, 3);
265 0 : if (IS_ERR(trans)) {
266 0 : ret = PTR_ERR(trans);
267 0 : trans = NULL;
268 0 : goto out;
269 : }
270 0 : drop_args.path = path;
271 0 : drop_args.start = drop_start;
272 0 : drop_args.end = aligned_end;
273 0 : drop_args.drop_cache = true;
274 0 : ret = btrfs_drop_extents(trans, root, BTRFS_I(dst), &drop_args);
275 0 : if (ret)
276 0 : goto out;
277 0 : ret = btrfs_insert_empty_item(trans, root, path, new_key, size);
278 0 : if (ret)
279 0 : goto out;
280 :
281 0 : write_extent_buffer(path->nodes[0], inline_data,
282 0 : btrfs_item_ptr_offset(path->nodes[0],
283 : path->slots[0]),
284 : size);
285 0 : btrfs_update_inode_bytes(BTRFS_I(dst), datal, drop_args.bytes_found);
286 0 : btrfs_set_inode_full_sync(BTRFS_I(dst));
287 0 : ret = btrfs_inode_set_file_extent_range(BTRFS_I(dst), 0, aligned_end);
288 0 : out:
289 0 : 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 0 : trans = btrfs_start_transaction(root, 1);
297 0 : if (IS_ERR(trans)) {
298 0 : ret = PTR_ERR(trans);
299 0 : trans = NULL;
300 : }
301 : }
302 0 : if (ret && trans) {
303 0 : btrfs_abort_transaction(trans, ret);
304 0 : btrfs_end_transaction(trans);
305 : }
306 0 : if (!ret)
307 0 : *trans_out = trans;
308 :
309 : return ret;
310 :
311 0 : copy_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 0 : btrfs_release_path(path);
321 :
322 0 : ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
323 : inline_data, size, datal, comp_type);
324 0 : 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 : */
338 0 : static 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 0 : struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
343 0 : struct btrfs_path *path = NULL;
344 0 : struct extent_buffer *leaf;
345 0 : struct btrfs_trans_handle *trans;
346 0 : char *buf = NULL;
347 0 : struct btrfs_key key;
348 0 : u32 nritems;
349 0 : int slot;
350 0 : int ret;
351 0 : const u64 len = olen_aligned;
352 0 : u64 last_dest_end = destoff;
353 0 : u64 prev_extent_end = off;
354 :
355 0 : ret = -ENOMEM;
356 0 : buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
357 0 : if (!buf)
358 : return ret;
359 :
360 0 : path = btrfs_alloc_path();
361 0 : if (!path) {
362 0 : kvfree(buf);
363 0 : return ret;
364 : }
365 :
366 0 : path->reada = READA_FORWARD;
367 : /* Clone data */
368 0 : key.objectid = btrfs_ino(BTRFS_I(src));
369 0 : key.type = BTRFS_EXTENT_DATA_KEY;
370 0 : key.offset = off;
371 :
372 0 : while (1) {
373 0 : struct btrfs_file_extent_item *extent;
374 0 : u64 extent_gen;
375 0 : int type;
376 0 : u32 size;
377 0 : struct btrfs_key new_key;
378 0 : u64 disko = 0, diskl = 0;
379 0 : u64 datao = 0, datal = 0;
380 0 : u8 comp;
381 0 : u64 drop_start;
382 :
383 : /* Note the key will change type as we walk through the tree */
384 0 : ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
385 : 0, 0);
386 0 : if (ret < 0)
387 0 : 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 0 : if (key.offset == off && ret > 0 && path->slots[0] > 0) {
394 0 : btrfs_item_key_to_cpu(path->nodes[0], &key,
395 : path->slots[0] - 1);
396 0 : if (key.type == BTRFS_EXTENT_DATA_KEY)
397 0 : path->slots[0]--;
398 : }
399 :
400 0 : nritems = btrfs_header_nritems(path->nodes[0]);
401 0 : process_slot:
402 0 : if (path->slots[0] >= nritems) {
403 0 : ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
404 0 : if (ret < 0)
405 0 : goto out;
406 0 : if (ret > 0)
407 : break;
408 0 : nritems = btrfs_header_nritems(path->nodes[0]);
409 : }
410 0 : leaf = path->nodes[0];
411 0 : slot = path->slots[0];
412 :
413 0 : btrfs_item_key_to_cpu(leaf, &key, slot);
414 0 : if (key.type > BTRFS_EXTENT_DATA_KEY ||
415 0 : key.objectid != btrfs_ino(BTRFS_I(src)))
416 : break;
417 :
418 0 : ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
419 :
420 0 : extent = btrfs_item_ptr(leaf, slot,
421 : struct btrfs_file_extent_item);
422 0 : extent_gen = btrfs_file_extent_generation(leaf, extent);
423 0 : comp = btrfs_file_extent_compression(leaf, extent);
424 0 : type = btrfs_file_extent_type(leaf, extent);
425 0 : if (type == BTRFS_FILE_EXTENT_REG ||
426 : type == BTRFS_FILE_EXTENT_PREALLOC) {
427 0 : disko = btrfs_file_extent_disk_bytenr(leaf, extent);
428 0 : diskl = btrfs_file_extent_disk_num_bytes(leaf, extent);
429 0 : datao = btrfs_file_extent_offset(leaf, extent);
430 0 : datal = btrfs_file_extent_num_bytes(leaf, extent);
431 0 : } else if (type == BTRFS_FILE_EXTENT_INLINE) {
432 : /* Take upper bound, may be compressed */
433 0 : 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 0 : if (key.offset + datal <= prev_extent_end) {
448 0 : path->slots[0]++;
449 0 : goto process_slot;
450 0 : } else if (key.offset >= off + len) {
451 : break;
452 : }
453 :
454 0 : prev_extent_end = key.offset + datal;
455 0 : size = btrfs_item_size(leaf, slot);
456 0 : read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot),
457 : size);
458 :
459 0 : btrfs_release_path(path);
460 :
461 0 : memcpy(&new_key, &key, sizeof(new_key));
462 0 : new_key.objectid = btrfs_ino(BTRFS_I(inode));
463 0 : if (off <= key.offset)
464 0 : new_key.offset = key.offset + destoff - off;
465 : else
466 0 : 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 0 : if (new_key.offset != last_dest_end)
475 : drop_start = last_dest_end;
476 : else
477 0 : drop_start = new_key.offset;
478 :
479 0 : if (type == BTRFS_FILE_EXTENT_REG ||
480 : type == BTRFS_FILE_EXTENT_PREALLOC) {
481 0 : struct btrfs_replace_extent_info clone_info;
482 :
483 : /*
484 : * a | --- range to clone ---| b
485 : * | ------------- extent ------------- |
486 : */
487 :
488 : /* Subtract range b */
489 0 : if (key.offset + datal > off + len)
490 0 : datal = off + len - key.offset;
491 :
492 : /* Subtract range a */
493 0 : if (off > key.offset) {
494 0 : datao += off - key.offset;
495 0 : datal -= off - key.offset;
496 : }
497 :
498 0 : clone_info.disk_offset = disko;
499 0 : clone_info.disk_len = diskl;
500 0 : clone_info.data_offset = datao;
501 0 : clone_info.data_len = datal;
502 0 : clone_info.file_offset = new_key.offset;
503 0 : clone_info.extent_buf = buf;
504 0 : clone_info.is_new_extent = false;
505 0 : clone_info.update_times = !no_time_update;
506 0 : ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
507 0 : drop_start, new_key.offset + datal - 1,
508 : &clone_info, &trans);
509 0 : if (ret)
510 0 : goto out;
511 : } else {
512 0 : 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 0 : ASSERT(key.offset == 0);
522 0 : ASSERT(datal <= fs_info->sectorsize);
523 0 : if (WARN_ON(type != BTRFS_FILE_EXTENT_INLINE) ||
524 0 : WARN_ON(key.offset != 0) ||
525 0 : WARN_ON(datal > fs_info->sectorsize)) {
526 0 : ret = -EUCLEAN;
527 0 : goto out;
528 : }
529 :
530 0 : ret = clone_copy_inline_extent(inode, path, &new_key,
531 : drop_start, datal, size,
532 : comp, buf, &trans);
533 0 : if (ret)
534 0 : goto out;
535 : }
536 :
537 0 : 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 0 : if (extent_gen == trans->transid && disko > 0)
553 0 : BTRFS_I(src)->last_reflink_trans = trans->transid;
554 :
555 0 : BTRFS_I(inode)->last_reflink_trans = trans->transid;
556 :
557 0 : last_dest_end = ALIGN(new_key.offset + datal,
558 : fs_info->sectorsize);
559 0 : ret = clone_finish_inode_update(trans, inode, last_dest_end,
560 : destoff, olen, no_time_update);
561 0 : if (ret)
562 0 : goto out;
563 0 : if (new_key.offset + datal >= destoff + len)
564 : break;
565 :
566 0 : btrfs_release_path(path);
567 0 : key.offset = prev_extent_end;
568 :
569 0 : if (fatal_signal_pending(current)) {
570 0 : ret = -EINTR;
571 0 : goto out;
572 : }
573 :
574 0 : cond_resched();
575 : }
576 0 : ret = 0;
577 :
578 0 : 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 0 : 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 0 : if (last_dest_end >= i_size_read(inode))
602 0 : btrfs_set_inode_full_sync(BTRFS_I(inode));
603 :
604 0 : ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
605 : last_dest_end, destoff + len - 1, NULL, &trans);
606 0 : if (ret)
607 0 : goto out;
608 :
609 0 : ret = clone_finish_inode_update(trans, inode, destoff + len,
610 : destoff, olen, no_time_update);
611 : }
612 :
613 0 : out:
614 0 : btrfs_free_path(path);
615 0 : kvfree(buf);
616 0 : clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &BTRFS_I(inode)->runtime_flags);
617 :
618 : return ret;
619 : }
620 :
621 0 : static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
622 : struct inode *inode2, u64 loff2, u64 len)
623 : {
624 0 : unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1, NULL);
625 0 : unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1, NULL);
626 0 : }
627 :
628 0 : static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
629 : struct inode *inode2, u64 loff2, u64 len)
630 : {
631 0 : u64 range1_end = loff1 + len - 1;
632 0 : u64 range2_end = loff2 + len - 1;
633 :
634 0 : if (inode1 < inode2) {
635 : swap(inode1, inode2);
636 : swap(loff1, loff2);
637 : swap(range1_end, range2_end);
638 0 : } else if (inode1 == inode2 && loff2 < loff1) {
639 0 : swap(loff1, loff2);
640 0 : swap(range1_end, range2_end);
641 : }
642 :
643 0 : lock_extent(&BTRFS_I(inode1)->io_tree, loff1, range1_end, NULL);
644 0 : lock_extent(&BTRFS_I(inode2)->io_tree, loff2, range2_end, NULL);
645 :
646 0 : btrfs_assert_inode_range_clean(BTRFS_I(inode1), loff1, range1_end);
647 0 : btrfs_assert_inode_range_clean(BTRFS_I(inode2), loff2, range2_end);
648 0 : }
649 :
650 0 : static void btrfs_double_mmap_lock(struct inode *inode1, struct inode *inode2)
651 : {
652 0 : if (inode1 < inode2)
653 0 : swap(inode1, inode2);
654 0 : down_write(&BTRFS_I(inode1)->i_mmap_lock);
655 0 : down_write_nested(&BTRFS_I(inode2)->i_mmap_lock, SINGLE_DEPTH_NESTING);
656 0 : }
657 :
658 : static void btrfs_double_mmap_unlock(struct inode *inode1, struct inode *inode2)
659 : {
660 0 : up_write(&BTRFS_I(inode1)->i_mmap_lock);
661 0 : up_write(&BTRFS_I(inode2)->i_mmap_lock);
662 : }
663 :
664 0 : static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len,
665 : struct inode *dst, u64 dst_loff)
666 : {
667 0 : struct btrfs_fs_info *fs_info = BTRFS_I(src)->root->fs_info;
668 0 : const u64 bs = fs_info->sb->s_blocksize;
669 0 : int ret;
670 :
671 : /*
672 : * Lock destination range to serialize with concurrent readahead() and
673 : * source range to serialize with relocation.
674 : */
675 0 : btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
676 0 : ret = btrfs_clone(src, dst, loff, len, ALIGN(len, bs), dst_loff, 1);
677 0 : btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
678 :
679 0 : btrfs_btree_balance_dirty(fs_info);
680 :
681 0 : return ret;
682 : }
683 :
684 0 : static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
685 : struct inode *dst, u64 dst_loff)
686 : {
687 0 : int ret = 0;
688 0 : u64 i, tail_len, chunk_count;
689 0 : struct btrfs_root *root_dst = BTRFS_I(dst)->root;
690 :
691 0 : spin_lock(&root_dst->root_item_lock);
692 0 : if (root_dst->send_in_progress) {
693 0 : 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 0 : spin_unlock(&root_dst->root_item_lock);
698 0 : return -EAGAIN;
699 : }
700 0 : root_dst->dedupe_in_progress++;
701 0 : spin_unlock(&root_dst->root_item_lock);
702 :
703 0 : tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
704 0 : chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
705 :
706 0 : for (i = 0; i < chunk_count; i++) {
707 0 : ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,
708 : dst, dst_loff);
709 0 : if (ret)
710 0 : goto out;
711 :
712 0 : loff += BTRFS_MAX_DEDUPE_LEN;
713 0 : dst_loff += BTRFS_MAX_DEDUPE_LEN;
714 : }
715 :
716 0 : if (tail_len > 0)
717 0 : ret = btrfs_extent_same_range(src, loff, tail_len, dst, dst_loff);
718 0 : out:
719 0 : spin_lock(&root_dst->root_item_lock);
720 0 : root_dst->dedupe_in_progress--;
721 0 : spin_unlock(&root_dst->root_item_lock);
722 :
723 0 : return ret;
724 : }
725 :
726 0 : static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
727 : u64 off, u64 olen, u64 destoff)
728 : {
729 0 : struct inode *inode = file_inode(file);
730 0 : struct inode *src = file_inode(file_src);
731 0 : struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
732 0 : int ret;
733 0 : int wb_ret;
734 0 : u64 len = olen;
735 0 : 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 0 : if (off + len == src->i_size)
744 0 : len = ALIGN(src->i_size, bs) - off;
745 :
746 0 : if (destoff > inode->i_size) {
747 0 : const u64 wb_start = ALIGN_DOWN(inode->i_size, bs);
748 :
749 0 : ret = btrfs_cont_expand(BTRFS_I(inode), inode->i_size, destoff);
750 0 : 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 0 : ret = btrfs_wait_ordered_range(inode, wb_start,
762 : destoff - wb_start);
763 0 : 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 0 : btrfs_double_extent_lock(src, off, inode, destoff, len);
772 0 : ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
773 0 : 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 0 : wb_ret = btrfs_wait_ordered_range(inode, destoff, len);
781 0 : 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 0 : truncate_inode_pages_range(&inode->i_data,
787 0 : round_down(destoff, PAGE_SIZE),
788 0 : round_up(destoff + len, PAGE_SIZE) - 1);
789 :
790 0 : btrfs_btree_balance_dirty(fs_info);
791 :
792 0 : return ret;
793 : }
794 :
795 0 : static 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 0 : struct inode *inode_in = file_inode(file_in);
800 0 : struct inode *inode_out = file_inode(file_out);
801 0 : u64 bs = BTRFS_I(inode_out)->root->fs_info->sb->s_blocksize;
802 0 : u64 wb_len;
803 0 : int ret;
804 :
805 0 : if (!(remap_flags & REMAP_FILE_DEDUP)) {
806 0 : struct btrfs_root *root_out = BTRFS_I(inode_out)->root;
807 :
808 0 : 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 0 : if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) !=
816 0 : (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 0 : if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP))
835 0 : wb_len = ALIGN(inode_in->i_size, bs) - ALIGN_DOWN(pos_in, bs);
836 : else
837 0 : 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 0 : ret = filemap_flush(inode_in->i_mapping);
857 0 : if (ret < 0)
858 : return ret;
859 :
860 0 : ret = btrfs_wait_ordered_range(inode_in, ALIGN_DOWN(pos_in, bs),
861 : wb_len);
862 0 : if (ret < 0)
863 : return ret;
864 0 : ret = btrfs_wait_ordered_range(inode_out, ALIGN_DOWN(pos_out, bs),
865 : wb_len);
866 0 : if (ret < 0)
867 : return ret;
868 :
869 0 : return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
870 : len, remap_flags);
871 : }
872 :
873 0 : static bool file_sync_write(const struct file *file)
874 : {
875 0 : if (file->f_flags & (__O_SYNC | O_DSYNC))
876 : return true;
877 0 : if (IS_SYNC(file_inode(file)))
878 0 : return true;
879 :
880 : return false;
881 : }
882 :
883 0 : loff_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 0 : struct inode *src_inode = file_inode(src_file);
888 0 : struct inode *dst_inode = file_inode(dst_file);
889 0 : bool same_inode = dst_inode == src_inode;
890 0 : int ret;
891 :
892 0 : if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
893 : return -EINVAL;
894 :
895 0 : if (same_inode) {
896 0 : btrfs_inode_lock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);
897 : } else {
898 0 : lock_two_nondirectories(src_inode, dst_inode);
899 0 : btrfs_double_mmap_lock(src_inode, dst_inode);
900 : }
901 :
902 0 : ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff,
903 : &len, remap_flags);
904 0 : if (ret < 0 || len == 0)
905 0 : goto out_unlock;
906 :
907 0 : if (remap_flags & REMAP_FILE_DEDUP)
908 0 : ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff);
909 : else
910 0 : ret = btrfs_clone_files(dst_file, src_file, off, len, destoff);
911 :
912 0 : out_unlock:
913 0 : if (same_inode) {
914 0 : btrfs_inode_unlock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);
915 : } else {
916 0 : btrfs_double_mmap_unlock(src_inode, dst_inode);
917 0 : 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 0 : if (ret == 0 && len > 0 &&
928 0 : (file_sync_write(src_file) || file_sync_write(dst_file))) {
929 0 : ret = btrfs_sync_file(src_file, off, off + len - 1, 0);
930 0 : if (ret == 0)
931 0 : ret = btrfs_sync_file(dst_file, destoff,
932 0 : destoff + len - 1, 0);
933 : }
934 :
935 0 : return ret < 0 ? ret : len;
936 : }
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