1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2012 Alexander Block. All rights reserved.
4 */
5
6 #include <linux/bsearch.h>
7 #include <linux/fs.h>
8 #include <linux/file.h>
9 #include <linux/sort.h>
10 #include <linux/mount.h>
11 #include <linux/xattr.h>
12 #include <linux/posix_acl_xattr.h>
13 #include <linux/radix-tree.h>
14 #include <linux/vmalloc.h>
15 #include <linux/string.h>
16 #include <linux/compat.h>
17 #include <linux/crc32c.h>
18 #include <linux/fsverity.h>
19
20 #include "send.h"
21 #include "ctree.h"
22 #include "backref.h"
23 #include "locking.h"
24 #include "disk-io.h"
25 #include "btrfs_inode.h"
26 #include "transaction.h"
27 #include "compression.h"
28 #include "print-tree.h"
29 #include "accessors.h"
30 #include "dir-item.h"
31 #include "file-item.h"
32 #include "ioctl.h"
33 #include "verity.h"
34 #include "lru_cache.h"
35
36 /*
37 * Maximum number of references an extent can have in order for us to attempt to
38 * issue clone operations instead of write operations. This currently exists to
39 * avoid hitting limitations of the backreference walking code (taking a lot of
40 * time and using too much memory for extents with large number of references).
41 */
42 #define SEND_MAX_EXTENT_REFS 1024
43
44 /*
45 * A fs_path is a helper to dynamically build path names with unknown size.
46 * It reallocates the internal buffer on demand.
47 * It allows fast adding of path elements on the right side (normal path) and
48 * fast adding to the left side (reversed path). A reversed path can also be
49 * unreversed if needed.
50 */
51 struct fs_path {
52 union {
53 struct {
54 char *start;
55 char *end;
56
57 char *buf;
58 unsigned short buf_len:15;
59 unsigned short reversed:1;
60 char inline_buf[];
61 };
62 /*
63 * Average path length does not exceed 200 bytes, we'll have
64 * better packing in the slab and higher chance to satisfy
65 * a allocation later during send.
66 */
67 char pad[256];
68 };
69 };
70 #define FS_PATH_INLINE_SIZE \
71 (sizeof(struct fs_path) - offsetof(struct fs_path, inline_buf))
72
73
74 /* reused for each extent */
75 struct clone_root {
76 struct btrfs_root *root;
77 u64 ino;
78 u64 offset;
79 u64 num_bytes;
80 bool found_ref;
81 };
82
83 #define SEND_MAX_NAME_CACHE_SIZE 256
84
85 /*
86 * Limit the root_ids array of struct backref_cache_entry to 17 elements.
87 * This makes the size of a cache entry to be exactly 192 bytes on x86_64, which
88 * can be satisfied from the kmalloc-192 slab, without wasting any space.
89 * The most common case is to have a single root for cloning, which corresponds
90 * to the send root. Having the user specify more than 16 clone roots is not
91 * common, and in such rare cases we simply don't use caching if the number of
92 * cloning roots that lead down to a leaf is more than 17.
93 */
94 #define SEND_MAX_BACKREF_CACHE_ROOTS 17
95
96 /*
97 * Max number of entries in the cache.
98 * With SEND_MAX_BACKREF_CACHE_ROOTS as 17, the size in bytes, excluding
99 * maple tree's internal nodes, is 24K.
100 */
101 #define SEND_MAX_BACKREF_CACHE_SIZE 128
102
103 /*
104 * A backref cache entry maps a leaf to a list of IDs of roots from which the
105 * leaf is accessible and we can use for clone operations.
106 * With SEND_MAX_BACKREF_CACHE_ROOTS as 12, each cache entry is 128 bytes (on
107 * x86_64).
108 */
109 struct backref_cache_entry {
110 struct btrfs_lru_cache_entry entry;
111 u64 root_ids[SEND_MAX_BACKREF_CACHE_ROOTS];
112 /* Number of valid elements in the root_ids array. */
113 int num_roots;
114 };
115
116 /* See the comment at lru_cache.h about struct btrfs_lru_cache_entry. */
117 static_assert(offsetof(struct backref_cache_entry, entry) == 0);
118
119 /*
120 * Max number of entries in the cache that stores directories that were already
121 * created. The cache uses raw struct btrfs_lru_cache_entry entries, so it uses
122 * at most 4096 bytes - sizeof(struct btrfs_lru_cache_entry) is 48 bytes, but
123 * the kmalloc-64 slab is used, so we get 4096 bytes (64 bytes * 64).
124 */
125 #define SEND_MAX_DIR_CREATED_CACHE_SIZE 64
126
127 /*
128 * Max number of entries in the cache that stores directories that were already
129 * created. The cache uses raw struct btrfs_lru_cache_entry entries, so it uses
130 * at most 4096 bytes - sizeof(struct btrfs_lru_cache_entry) is 48 bytes, but
131 * the kmalloc-64 slab is used, so we get 4096 bytes (64 bytes * 64).
132 */
133 #define SEND_MAX_DIR_UTIMES_CACHE_SIZE 64
134
135 struct send_ctx {
136 struct file *send_filp;
137 loff_t send_off;
138 char *send_buf;
139 u32 send_size;
140 u32 send_max_size;
141 /*
142 * Whether BTRFS_SEND_A_DATA attribute was already added to current
143 * command (since protocol v2, data must be the last attribute).
144 */
145 bool put_data;
146 struct page **send_buf_pages;
147 u64 flags; /* 'flags' member of btrfs_ioctl_send_args is u64 */
148 /* Protocol version compatibility requested */
149 u32 proto;
150
151 struct btrfs_root *send_root;
152 struct btrfs_root *parent_root;
153 struct clone_root *clone_roots;
154 int clone_roots_cnt;
155
156 /* current state of the compare_tree call */
157 struct btrfs_path *left_path;
158 struct btrfs_path *right_path;
159 struct btrfs_key *cmp_key;
160
161 /*
162 * Keep track of the generation of the last transaction that was used
163 * for relocating a block group. This is periodically checked in order
164 * to detect if a relocation happened since the last check, so that we
165 * don't operate on stale extent buffers for nodes (level >= 1) or on
166 * stale disk_bytenr values of file extent items.
167 */
168 u64 last_reloc_trans;
169
170 /*
171 * infos of the currently processed inode. In case of deleted inodes,
172 * these are the values from the deleted inode.
173 */
174 u64 cur_ino;
175 u64 cur_inode_gen;
176 u64 cur_inode_size;
177 u64 cur_inode_mode;
178 u64 cur_inode_rdev;
179 u64 cur_inode_last_extent;
180 u64 cur_inode_next_write_offset;
181 bool cur_inode_new;
182 bool cur_inode_new_gen;
183 bool cur_inode_deleted;
184 bool ignore_cur_inode;
185 bool cur_inode_needs_verity;
186 void *verity_descriptor;
187
188 u64 send_progress;
189
190 struct list_head new_refs;
191 struct list_head deleted_refs;
192
193 struct btrfs_lru_cache name_cache;
194
195 /*
196 * The inode we are currently processing. It's not NULL only when we
197 * need to issue write commands for data extents from this inode.
198 */
199 struct inode *cur_inode;
200 struct file_ra_state ra;
201 u64 page_cache_clear_start;
202 bool clean_page_cache;
203
204 /*
205 * We process inodes by their increasing order, so if before an
206 * incremental send we reverse the parent/child relationship of
207 * directories such that a directory with a lower inode number was
208 * the parent of a directory with a higher inode number, and the one
209 * becoming the new parent got renamed too, we can't rename/move the
210 * directory with lower inode number when we finish processing it - we
211 * must process the directory with higher inode number first, then
212 * rename/move it and then rename/move the directory with lower inode
213 * number. Example follows.
214 *
215 * Tree state when the first send was performed:
216 *
217 * .
218 * |-- a (ino 257)
219 * |-- b (ino 258)
220 * |
221 * |
222 * |-- c (ino 259)
223 * | |-- d (ino 260)
224 * |
225 * |-- c2 (ino 261)
226 *
227 * Tree state when the second (incremental) send is performed:
228 *
229 * .
230 * |-- a (ino 257)
231 * |-- b (ino 258)
232 * |-- c2 (ino 261)
233 * |-- d2 (ino 260)
234 * |-- cc (ino 259)
235 *
236 * The sequence of steps that lead to the second state was:
237 *
238 * mv /a/b/c/d /a/b/c2/d2
239 * mv /a/b/c /a/b/c2/d2/cc
240 *
241 * "c" has lower inode number, but we can't move it (2nd mv operation)
242 * before we move "d", which has higher inode number.
243 *
244 * So we just memorize which move/rename operations must be performed
245 * later when their respective parent is processed and moved/renamed.
246 */
247
248 /* Indexed by parent directory inode number. */
249 struct rb_root pending_dir_moves;
250
251 /*
252 * Reverse index, indexed by the inode number of a directory that
253 * is waiting for the move/rename of its immediate parent before its
254 * own move/rename can be performed.
255 */
256 struct rb_root waiting_dir_moves;
257
258 /*
259 * A directory that is going to be rm'ed might have a child directory
260 * which is in the pending directory moves index above. In this case,
261 * the directory can only be removed after the move/rename of its child
262 * is performed. Example:
263 *
264 * Parent snapshot:
265 *
266 * . (ino 256)
267 * |-- a/ (ino 257)
268 * |-- b/ (ino 258)
269 * |-- c/ (ino 259)
270 * | |-- x/ (ino 260)
271 * |
272 * |-- y/ (ino 261)
273 *
274 * Send snapshot:
275 *
276 * . (ino 256)
277 * |-- a/ (ino 257)
278 * |-- b/ (ino 258)
279 * |-- YY/ (ino 261)
280 * |-- x/ (ino 260)
281 *
282 * Sequence of steps that lead to the send snapshot:
283 * rm -f /a/b/c/foo.txt
284 * mv /a/b/y /a/b/YY
285 * mv /a/b/c/x /a/b/YY
286 * rmdir /a/b/c
287 *
288 * When the child is processed, its move/rename is delayed until its
289 * parent is processed (as explained above), but all other operations
290 * like update utimes, chown, chgrp, etc, are performed and the paths
291 * that it uses for those operations must use the orphanized name of
292 * its parent (the directory we're going to rm later), so we need to
293 * memorize that name.
294 *
295 * Indexed by the inode number of the directory to be deleted.
296 */
297 struct rb_root orphan_dirs;
298
299 struct rb_root rbtree_new_refs;
300 struct rb_root rbtree_deleted_refs;
301
302 struct btrfs_lru_cache backref_cache;
303 u64 backref_cache_last_reloc_trans;
304
305 struct btrfs_lru_cache dir_created_cache;
306 struct btrfs_lru_cache dir_utimes_cache;
307 };
308
309 struct pending_dir_move {
310 struct rb_node node;
311 struct list_head list;
312 u64 parent_ino;
313 u64 ino;
314 u64 gen;
315 struct list_head update_refs;
316 };
317
318 struct waiting_dir_move {
319 struct rb_node node;
320 u64 ino;
321 /*
322 * There might be some directory that could not be removed because it
323 * was waiting for this directory inode to be moved first. Therefore
324 * after this directory is moved, we can try to rmdir the ino rmdir_ino.
325 */
326 u64 rmdir_ino;
327 u64 rmdir_gen;
328 bool orphanized;
329 };
330
331 struct orphan_dir_info {
332 struct rb_node node;
333 u64 ino;
334 u64 gen;
335 u64 last_dir_index_offset;
336 u64 dir_high_seq_ino;
337 };
338
339 struct name_cache_entry {
340 /*
341 * The key in the entry is an inode number, and the generation matches
342 * the inode's generation.
343 */
344 struct btrfs_lru_cache_entry entry;
345 u64 parent_ino;
346 u64 parent_gen;
347 int ret;
348 int need_later_update;
349 /* Name length without NUL terminator. */
350 int name_len;
351 /* Not NUL terminated. */
352 char name[] __counted_by(name_len) __nonstring;
353 };
354
355 /* See the comment at lru_cache.h about struct btrfs_lru_cache_entry. */
356 static_assert(offsetof(struct name_cache_entry, entry) == 0);
357
358 #define ADVANCE 1
359 #define ADVANCE_ONLY_NEXT -1
360
361 enum btrfs_compare_tree_result {
362 BTRFS_COMPARE_TREE_NEW,
363 BTRFS_COMPARE_TREE_DELETED,
364 BTRFS_COMPARE_TREE_CHANGED,
365 BTRFS_COMPARE_TREE_SAME,
366 };
367
368 __cold
369 static void inconsistent_snapshot_error(struct send_ctx *sctx,
370 enum btrfs_compare_tree_result result,
371 const char *what)
372 {
373 const char *result_string;
374
375 switch (result) {
376 case BTRFS_COMPARE_TREE_NEW:
377 result_string = "new";
378 break;
379 case BTRFS_COMPARE_TREE_DELETED:
380 result_string = "deleted";
381 break;
382 case BTRFS_COMPARE_TREE_CHANGED:
383 result_string = "updated";
384 break;
385 case BTRFS_COMPARE_TREE_SAME:
386 ASSERT(0);
387 result_string = "unchanged";
388 break;
389 default:
390 ASSERT(0);
391 result_string = "unexpected";
392 }
393
394 btrfs_err(sctx->send_root->fs_info,
395 "Send: inconsistent snapshot, found %s %s for inode %llu without updated inode item, send root is %llu, parent root is %llu",
396 result_string, what, sctx->cmp_key->objectid,
397 btrfs_root_id(sctx->send_root),
398 (sctx->parent_root ? btrfs_root_id(sctx->parent_root) : 0));
399 }
400
401 __maybe_unused
402 static bool proto_cmd_ok(const struct send_ctx *sctx, int cmd)
403 {
404 switch (sctx->proto) {
405 case 1: return cmd <= BTRFS_SEND_C_MAX_V1;
406 case 2: return cmd <= BTRFS_SEND_C_MAX_V2;
407 case 3: return cmd <= BTRFS_SEND_C_MAX_V3;
408 default: return false;
409 }
410 }
411
412 static int is_waiting_for_move(struct send_ctx *sctx, u64 ino);
413
414 static struct waiting_dir_move *
415 get_waiting_dir_move(struct send_ctx *sctx, u64 ino);
416
417 static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen);
418
419 static int need_send_hole(struct send_ctx *sctx)
420 {
421 return (sctx->parent_root && !sctx->cur_inode_new &&
422 !sctx->cur_inode_new_gen && !sctx->cur_inode_deleted &&
423 S_ISREG(sctx->cur_inode_mode));
424 }
425
426 static void fs_path_reset(struct fs_path *p)
427 {
428 if (p->reversed) {
429 p->start = p->buf + p->buf_len - 1;
430 p->end = p->start;
431 *p->start = 0;
432 } else {
433 p->start = p->buf;
434 p->end = p->start;
435 *p->start = 0;
436 }
437 }
438
439 static struct fs_path *fs_path_alloc(void)
440 {
441 struct fs_path *p;
442
443 p = kmalloc(sizeof(*p), GFP_KERNEL);
444 if (!p)
445 return NULL;
446 p->reversed = 0;
447 p->buf = p->inline_buf;
448 p->buf_len = FS_PATH_INLINE_SIZE;
449 fs_path_reset(p);
450 return p;
451 }
452
453 static struct fs_path *fs_path_alloc_reversed(void)
454 {
455 struct fs_path *p;
456
457 p = fs_path_alloc();
458 if (!p)
459 return NULL;
460 p->reversed = 1;
461 fs_path_reset(p);
462 return p;
463 }
464
465 static void fs_path_free(struct fs_path *p)
466 {
467 if (!p)
468 return;
469 if (p->buf != p->inline_buf)
470 kfree(p->buf);
471 kfree(p);
472 }
473
474 static int fs_path_len(struct fs_path *p)
475 {
476 return p->end - p->start;
477 }
478
479 static int fs_path_ensure_buf(struct fs_path *p, int len)
480 {
481 char *tmp_buf;
482 int path_len;
483 int old_buf_len;
484
485 len++;
486
487 if (p->buf_len >= len)
488 return 0;
489
490 if (len > PATH_MAX) {
491 WARN_ON(1);
492 return -ENOMEM;
493 }
494
495 path_len = p->end - p->start;
496 old_buf_len = p->buf_len;
497
498 /*
499 * Allocate to the next largest kmalloc bucket size, to let
500 * the fast path happen most of the time.
501 */
502 len = kmalloc_size_roundup(len);
503 /*
504 * First time the inline_buf does not suffice
505 */
506 if (p->buf == p->inline_buf) {
507 tmp_buf = kmalloc(len, GFP_KERNEL);
508 if (tmp_buf)
509 memcpy(tmp_buf, p->buf, old_buf_len);
510 } else {
511 tmp_buf = krealloc(p->buf, len, GFP_KERNEL);
512 }
513 if (!tmp_buf)
514 return -ENOMEM;
515 p->buf = tmp_buf;
516 p->buf_len = len;
517
518 if (p->reversed) {
519 tmp_buf = p->buf + old_buf_len - path_len - 1;
520 p->end = p->buf + p->buf_len - 1;
521 p->start = p->end - path_len;
522 memmove(p->start, tmp_buf, path_len + 1);
523 } else {
524 p->start = p->buf;
525 p->end = p->start + path_len;
526 }
527 return 0;
528 }
529
530 static int fs_path_prepare_for_add(struct fs_path *p, int name_len,
531 char **prepared)
532 {
533 int ret;
534 int new_len;
535
536 new_len = p->end - p->start + name_len;
537 if (p->start != p->end)
538 new_len++;
539 ret = fs_path_ensure_buf(p, new_len);
540 if (ret < 0)
541 goto out;
542
543 if (p->reversed) {
544 if (p->start != p->end)
545 *--p->start = '/';
546 p->start -= name_len;
547 *prepared = p->start;
548 } else {
549 if (p->start != p->end)
550 *p->end++ = '/';
551 *prepared = p->end;
552 p->end += name_len;
553 *p->end = 0;
554 }
555
556 out:
557 return ret;
558 }
559
560 static int fs_path_add(struct fs_path *p, const char *name, int name_len)
561 {
562 int ret;
563 char *prepared;
564
565 ret = fs_path_prepare_for_add(p, name_len, &prepared);
566 if (ret < 0)
567 goto out;
568 memcpy(prepared, name, name_len);
569
570 out:
571 return ret;
572 }
573
574 static int fs_path_add_path(struct fs_path *p, struct fs_path *p2)
575 {
576 int ret;
577 char *prepared;
578
579 ret = fs_path_prepare_for_add(p, p2->end - p2->start, &prepared);
580 if (ret < 0)
581 goto out;
582 memcpy(prepared, p2->start, p2->end - p2->start);
583
584 out:
585 return ret;
586 }
587
588 static int fs_path_add_from_extent_buffer(struct fs_path *p,
589 struct extent_buffer *eb,
590 unsigned long off, int len)
591 {
592 int ret;
593 char *prepared;
594
595 ret = fs_path_prepare_for_add(p, len, &prepared);
596 if (ret < 0)
597 goto out;
598
599 read_extent_buffer(eb, prepared, off, len);
600
601 out:
602 return ret;
603 }
604
605 static int fs_path_copy(struct fs_path *p, struct fs_path *from)
606 {
607 p->reversed = from->reversed;
608 fs_path_reset(p);
609
610 return fs_path_add_path(p, from);
611 }
612
613 static void fs_path_unreverse(struct fs_path *p)
614 {
615 char *tmp;
616 int len;
617
618 if (!p->reversed)
619 return;
620
621 tmp = p->start;
622 len = p->end - p->start;
623 p->start = p->buf;
624 p->end = p->start + len;
625 memmove(p->start, tmp, len + 1);
626 p->reversed = 0;
627 }
628
629 static struct btrfs_path *alloc_path_for_send(void)
630 {
631 struct btrfs_path *path;
632
633 path = btrfs_alloc_path();
634 if (!path)
635 return NULL;
636 path->search_commit_root = 1;
637 path->skip_locking = 1;
638 path->need_commit_sem = 1;
639 return path;
640 }
641
642 static int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off)
643 {
644 int ret;
645 u32 pos = 0;
646
647 while (pos < len) {
648 ret = kernel_write(filp, buf + pos, len - pos, off);
649 if (ret < 0)
650 return ret;
651 if (ret == 0)
652 return -EIO;
653 pos += ret;
654 }
655
656 return 0;
657 }
658
659 static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len)
660 {
661 struct btrfs_tlv_header *hdr;
662 int total_len = sizeof(*hdr) + len;
663 int left = sctx->send_max_size - sctx->send_size;
664
665 if (WARN_ON_ONCE(sctx->put_data))
666 return -EINVAL;
667
668 if (unlikely(left < total_len))
669 return -EOVERFLOW;
670
671 hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size);
672 put_unaligned_le16(attr, &hdr->tlv_type);
673 put_unaligned_le16(len, &hdr->tlv_len);
674 memcpy(hdr + 1, data, len);
675 sctx->send_size += total_len;
676
677 return 0;
678 }
679
680 #define TLV_PUT_DEFINE_INT(bits) \
681 static int tlv_put_u##bits(struct send_ctx *sctx, \
682 u##bits attr, u##bits value) \
683 { \
684 __le##bits __tmp = cpu_to_le##bits(value); \
685 return tlv_put(sctx, attr, &__tmp, sizeof(__tmp)); \
686 }
687
688 TLV_PUT_DEFINE_INT(8)
689 TLV_PUT_DEFINE_INT(32)
690 TLV_PUT_DEFINE_INT(64)
691
692 static int tlv_put_string(struct send_ctx *sctx, u16 attr,
693 const char *str, int len)
694 {
695 if (len == -1)
696 len = strlen(str);
697 return tlv_put(sctx, attr, str, len);
698 }
699
700 static int tlv_put_uuid(struct send_ctx *sctx, u16 attr,
701 const u8 *uuid)
702 {
703 return tlv_put(sctx, attr, uuid, BTRFS_UUID_SIZE);
704 }
705
706 static int tlv_put_btrfs_timespec(struct send_ctx *sctx, u16 attr,
707 struct extent_buffer *eb,
708 struct btrfs_timespec *ts)
709 {
710 struct btrfs_timespec bts;
711 read_extent_buffer(eb, &bts, (unsigned long)ts, sizeof(bts));
712 return tlv_put(sctx, attr, &bts, sizeof(bts));
713 }
714
715
716 #define TLV_PUT(sctx, attrtype, data, attrlen) \
717 do { \
718 ret = tlv_put(sctx, attrtype, data, attrlen); \
719 if (ret < 0) \
720 goto tlv_put_failure; \
721 } while (0)
722
723 #define TLV_PUT_INT(sctx, attrtype, bits, value) \
724 do { \
725 ret = tlv_put_u##bits(sctx, attrtype, value); \
726 if (ret < 0) \
727 goto tlv_put_failure; \
728 } while (0)
729
730 #define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data)
731 #define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data)
732 #define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data)
733 #define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data)
734 #define TLV_PUT_STRING(sctx, attrtype, str, len) \
735 do { \
736 ret = tlv_put_string(sctx, attrtype, str, len); \
737 if (ret < 0) \
738 goto tlv_put_failure; \
739 } while (0)
740 #define TLV_PUT_PATH(sctx, attrtype, p) \
741 do { \
742 ret = tlv_put_string(sctx, attrtype, p->start, \
743 p->end - p->start); \
744 if (ret < 0) \
745 goto tlv_put_failure; \
746 } while(0)
747 #define TLV_PUT_UUID(sctx, attrtype, uuid) \
748 do { \
749 ret = tlv_put_uuid(sctx, attrtype, uuid); \
750 if (ret < 0) \
751 goto tlv_put_failure; \
752 } while (0)
753 #define TLV_PUT_BTRFS_TIMESPEC(sctx, attrtype, eb, ts) \
754 do { \
755 ret = tlv_put_btrfs_timespec(sctx, attrtype, eb, ts); \
756 if (ret < 0) \
757 goto tlv_put_failure; \
758 } while (0)
759
760 static int send_header(struct send_ctx *sctx)
761 {
762 struct btrfs_stream_header hdr;
763
764 strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
765 hdr.version = cpu_to_le32(sctx->proto);
766 return write_buf(sctx->send_filp, &hdr, sizeof(hdr),
767 &sctx->send_off);
768 }
769
770 /*
771 * For each command/item we want to send to userspace, we call this function.
772 */
773 static int begin_cmd(struct send_ctx *sctx, int cmd)
774 {
775 struct btrfs_cmd_header *hdr;
776
777 if (WARN_ON(!sctx->send_buf))
778 return -EINVAL;
779
780 if (unlikely(sctx->send_size != 0)) {
781 btrfs_err(sctx->send_root->fs_info,
782 "send: command header buffer not empty cmd %d offset %llu",
783 cmd, sctx->send_off);
784 return -EINVAL;
785 }
786
787 sctx->send_size += sizeof(*hdr);
788 hdr = (struct btrfs_cmd_header *)sctx->send_buf;
789 put_unaligned_le16(cmd, &hdr->cmd);
790
791 return 0;
792 }
793
794 static int send_cmd(struct send_ctx *sctx)
795 {
796 int ret;
797 struct btrfs_cmd_header *hdr;
798 u32 crc;
799
800 hdr = (struct btrfs_cmd_header *)sctx->send_buf;
801 put_unaligned_le32(sctx->send_size - sizeof(*hdr), &hdr->len);
802 put_unaligned_le32(0, &hdr->crc);
803
804 crc = crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
805 put_unaligned_le32(crc, &hdr->crc);
806
807 ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size,
808 &sctx->send_off);
809
810 sctx->send_size = 0;
811 sctx->put_data = false;
812
813 return ret;
814 }
815
816 /*
817 * Sends a move instruction to user space
818 */
819 static int send_rename(struct send_ctx *sctx,
820 struct fs_path *from, struct fs_path *to)
821 {
822 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
823 int ret;
824
825 btrfs_debug(fs_info, "send_rename %s -> %s", from->start, to->start);
826
827 ret = begin_cmd(sctx, BTRFS_SEND_C_RENAME);
828 if (ret < 0)
829 goto out;
830
831 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, from);
832 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_TO, to);
833
834 ret = send_cmd(sctx);
835
836 tlv_put_failure:
837 out:
838 return ret;
839 }
840
841 /*
842 * Sends a link instruction to user space
843 */
844 static int send_link(struct send_ctx *sctx,
845 struct fs_path *path, struct fs_path *lnk)
846 {
847 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
848 int ret;
849
850 btrfs_debug(fs_info, "send_link %s -> %s", path->start, lnk->start);
851
852 ret = begin_cmd(sctx, BTRFS_SEND_C_LINK);
853 if (ret < 0)
854 goto out;
855
856 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
857 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, lnk);
858
859 ret = send_cmd(sctx);
860
861 tlv_put_failure:
862 out:
863 return ret;
864 }
865
866 /*
867 * Sends an unlink instruction to user space
868 */
869 static int send_unlink(struct send_ctx *sctx, struct fs_path *path)
870 {
871 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
872 int ret;
873
874 btrfs_debug(fs_info, "send_unlink %s", path->start);
875
876 ret = begin_cmd(sctx, BTRFS_SEND_C_UNLINK);
877 if (ret < 0)
878 goto out;
879
880 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
881
882 ret = send_cmd(sctx);
883
884 tlv_put_failure:
885 out:
886 return ret;
887 }
888
889 /*
890 * Sends a rmdir instruction to user space
891 */
892 static int send_rmdir(struct send_ctx *sctx, struct fs_path *path)
893 {
894 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
895 int ret;
896
897 btrfs_debug(fs_info, "send_rmdir %s", path->start);
898
899 ret = begin_cmd(sctx, BTRFS_SEND_C_RMDIR);
900 if (ret < 0)
901 goto out;
902
903 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
904
905 ret = send_cmd(sctx);
906
907 tlv_put_failure:
908 out:
909 return ret;
910 }
911
912 struct btrfs_inode_info {
913 u64 size;
914 u64 gen;
915 u64 mode;
916 u64 uid;
917 u64 gid;
918 u64 rdev;
919 u64 fileattr;
920 u64 nlink;
921 };
922
923 /*
924 * Helper function to retrieve some fields from an inode item.
925 */
926 static int get_inode_info(struct btrfs_root *root, u64 ino,
927 struct btrfs_inode_info *info)
928 {
929 int ret;
930 struct btrfs_path *path;
931 struct btrfs_inode_item *ii;
932 struct btrfs_key key;
933
934 path = alloc_path_for_send();
935 if (!path)
936 return -ENOMEM;
937
938 key.objectid = ino;
939 key.type = BTRFS_INODE_ITEM_KEY;
940 key.offset = 0;
941 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
942 if (ret) {
943 if (ret > 0)
944 ret = -ENOENT;
945 goto out;
946 }
947
948 if (!info)
949 goto out;
950
951 ii = btrfs_item_ptr(path->nodes[0], path->slots[0],
952 struct btrfs_inode_item);
953 info->size = btrfs_inode_size(path->nodes[0], ii);
954 info->gen = btrfs_inode_generation(path->nodes[0], ii);
955 info->mode = btrfs_inode_mode(path->nodes[0], ii);
956 info->uid = btrfs_inode_uid(path->nodes[0], ii);
957 info->gid = btrfs_inode_gid(path->nodes[0], ii);
958 info->rdev = btrfs_inode_rdev(path->nodes[0], ii);
959 info->nlink = btrfs_inode_nlink(path->nodes[0], ii);
960 /*
961 * Transfer the unchanged u64 value of btrfs_inode_item::flags, that's
962 * otherwise logically split to 32/32 parts.
963 */
964 info->fileattr = btrfs_inode_flags(path->nodes[0], ii);
965
966 out:
967 btrfs_free_path(path);
968 return ret;
969 }
970
971 static int get_inode_gen(struct btrfs_root *root, u64 ino, u64 *gen)
972 {
973 int ret;
974 struct btrfs_inode_info info = { 0 };
975
976 ASSERT(gen);
977
978 ret = get_inode_info(root, ino, &info);
979 *gen = info.gen;
980 return ret;
981 }
982
983 typedef int (*iterate_inode_ref_t)(int num, u64 dir, int index,
984 struct fs_path *p,
985 void *ctx);
986
987 /*
988 * Helper function to iterate the entries in ONE btrfs_inode_ref or
989 * btrfs_inode_extref.
990 * The iterate callback may return a non zero value to stop iteration. This can
991 * be a negative value for error codes or 1 to simply stop it.
992 *
993 * path must point to the INODE_REF or INODE_EXTREF when called.
994 */
995 static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path,
996 struct btrfs_key *found_key, int resolve,
997 iterate_inode_ref_t iterate, void *ctx)
998 {
999 struct extent_buffer *eb = path->nodes[0];
1000 struct btrfs_inode_ref *iref;
1001 struct btrfs_inode_extref *extref;
1002 struct btrfs_path *tmp_path;
1003 struct fs_path *p;
1004 u32 cur = 0;
1005 u32 total;
1006 int slot = path->slots[0];
1007 u32 name_len;
1008 char *start;
1009 int ret = 0;
1010 int num = 0;
1011 int index;
1012 u64 dir;
1013 unsigned long name_off;
1014 unsigned long elem_size;
1015 unsigned long ptr;
1016
1017 p = fs_path_alloc_reversed();
1018 if (!p)
1019 return -ENOMEM;
1020
1021 tmp_path = alloc_path_for_send();
1022 if (!tmp_path) {
1023 fs_path_free(p);
1024 return -ENOMEM;
1025 }
1026
1027
1028 if (found_key->type == BTRFS_INODE_REF_KEY) {
1029 ptr = (unsigned long)btrfs_item_ptr(eb, slot,
1030 struct btrfs_inode_ref);
1031 total = btrfs_item_size(eb, slot);
1032 elem_size = sizeof(*iref);
1033 } else {
1034 ptr = btrfs_item_ptr_offset(eb, slot);
1035 total = btrfs_item_size(eb, slot);
1036 elem_size = sizeof(*extref);
1037 }
1038
1039 while (cur < total) {
1040 fs_path_reset(p);
1041
1042 if (found_key->type == BTRFS_INODE_REF_KEY) {
1043 iref = (struct btrfs_inode_ref *)(ptr + cur);
1044 name_len = btrfs_inode_ref_name_len(eb, iref);
1045 name_off = (unsigned long)(iref + 1);
1046 index = btrfs_inode_ref_index(eb, iref);
1047 dir = found_key->offset;
1048 } else {
1049 extref = (struct btrfs_inode_extref *)(ptr + cur);
1050 name_len = btrfs_inode_extref_name_len(eb, extref);
1051 name_off = (unsigned long)&extref->name;
1052 index = btrfs_inode_extref_index(eb, extref);
1053 dir = btrfs_inode_extref_parent(eb, extref);
1054 }
1055
1056 if (resolve) {
1057 start = btrfs_ref_to_path(root, tmp_path, name_len,
1058 name_off, eb, dir,
1059 p->buf, p->buf_len);
1060 if (IS_ERR(start)) {
1061 ret = PTR_ERR(start);
1062 goto out;
1063 }
1064 if (start < p->buf) {
1065 /* overflow , try again with larger buffer */
1066 ret = fs_path_ensure_buf(p,
1067 p->buf_len + p->buf - start);
1068 if (ret < 0)
1069 goto out;
1070 start = btrfs_ref_to_path(root, tmp_path,
1071 name_len, name_off,
1072 eb, dir,
1073 p->buf, p->buf_len);
1074 if (IS_ERR(start)) {
1075 ret = PTR_ERR(start);
1076 goto out;
1077 }
1078 if (unlikely(start < p->buf)) {
1079 btrfs_err(root->fs_info,
1080 "send: path ref buffer underflow for key (%llu %u %llu)",
1081 found_key->objectid,
1082 found_key->type,
1083 found_key->offset);
1084 ret = -EINVAL;
1085 goto out;
1086 }
1087 }
1088 p->start = start;
1089 } else {
1090 ret = fs_path_add_from_extent_buffer(p, eb, name_off,
1091 name_len);
1092 if (ret < 0)
1093 goto out;
1094 }
1095
1096 cur += elem_size + name_len;
1097 ret = iterate(num, dir, index, p, ctx);
1098 if (ret)
1099 goto out;
1100 num++;
1101 }
1102
1103 out:
1104 btrfs_free_path(tmp_path);
1105 fs_path_free(p);
1106 return ret;
1107 }
1108
1109 typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key,
1110 const char *name, int name_len,
1111 const char *data, int data_len,
1112 void *ctx);
1113
1114 /*
1115 * Helper function to iterate the entries in ONE btrfs_dir_item.
1116 * The iterate callback may return a non zero value to stop iteration. This can
1117 * be a negative value for error codes or 1 to simply stop it.
1118 *
1119 * path must point to the dir item when called.
1120 */
1121 static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path,
1122 iterate_dir_item_t iterate, void *ctx)
1123 {
1124 int ret = 0;
1125 struct extent_buffer *eb;
1126 struct btrfs_dir_item *di;
1127 struct btrfs_key di_key;
1128 char *buf = NULL;
1129 int buf_len;
1130 u32 name_len;
1131 u32 data_len;
1132 u32 cur;
1133 u32 len;
1134 u32 total;
1135 int slot;
1136 int num;
1137
1138 /*
1139 * Start with a small buffer (1 page). If later we end up needing more
1140 * space, which can happen for xattrs on a fs with a leaf size greater
1141 * then the page size, attempt to increase the buffer. Typically xattr
1142 * values are small.
1143 */
1144 buf_len = PATH_MAX;
1145 buf = kmalloc(buf_len, GFP_KERNEL);
1146 if (!buf) {
1147 ret = -ENOMEM;
1148 goto out;
1149 }
1150
1151 eb = path->nodes[0];
1152 slot = path->slots[0];
1153 di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
1154 cur = 0;
1155 len = 0;
1156 total = btrfs_item_size(eb, slot);
1157
1158 num = 0;
1159 while (cur < total) {
1160 name_len = btrfs_dir_name_len(eb, di);
1161 data_len = btrfs_dir_data_len(eb, di);
1162 btrfs_dir_item_key_to_cpu(eb, di, &di_key);
1163
1164 if (btrfs_dir_ftype(eb, di) == BTRFS_FT_XATTR) {
1165 if (name_len > XATTR_NAME_MAX) {
1166 ret = -ENAMETOOLONG;
1167 goto out;
1168 }
1169 if (name_len + data_len >
1170 BTRFS_MAX_XATTR_SIZE(root->fs_info)) {
1171 ret = -E2BIG;
1172 goto out;
1173 }
1174 } else {
1175 /*
1176 * Path too long
1177 */
1178 if (name_len + data_len > PATH_MAX) {
1179 ret = -ENAMETOOLONG;
1180 goto out;
1181 }
1182 }
1183
1184 if (name_len + data_len > buf_len) {
1185 buf_len = name_len + data_len;
1186 if (is_vmalloc_addr(buf)) {
1187 vfree(buf);
1188 buf = NULL;
1189 } else {
1190 char *tmp = krealloc(buf, buf_len,
1191 GFP_KERNEL | __GFP_NOWARN);
1192
1193 if (!tmp)
1194 kfree(buf);
1195 buf = tmp;
1196 }
1197 if (!buf) {
1198 buf = kvmalloc(buf_len, GFP_KERNEL);
1199 if (!buf) {
1200 ret = -ENOMEM;
1201 goto out;
1202 }
1203 }
1204 }
1205
1206 read_extent_buffer(eb, buf, (unsigned long)(di + 1),
1207 name_len + data_len);
1208
1209 len = sizeof(*di) + name_len + data_len;
1210 di = (struct btrfs_dir_item *)((char *)di + len);
1211 cur += len;
1212
1213 ret = iterate(num, &di_key, buf, name_len, buf + name_len,
1214 data_len, ctx);
1215 if (ret < 0)
1216 goto out;
1217 if (ret) {
1218 ret = 0;
1219 goto out;
1220 }
1221
1222 num++;
1223 }
1224
1225 out:
1226 kvfree(buf);
1227 return ret;
1228 }
1229
1230 static int __copy_first_ref(int num, u64 dir, int index,
1231 struct fs_path *p, void *ctx)
1232 {
1233 int ret;
1234 struct fs_path *pt = ctx;
1235
1236 ret = fs_path_copy(pt, p);
1237 if (ret < 0)
1238 return ret;
1239
1240 /* we want the first only */
1241 return 1;
1242 }
1243
1244 /*
1245 * Retrieve the first path of an inode. If an inode has more then one
1246 * ref/hardlink, this is ignored.
1247 */
1248 static int get_inode_path(struct btrfs_root *root,
1249 u64 ino, struct fs_path *path)
1250 {
1251 int ret;
1252 struct btrfs_key key, found_key;
1253 struct btrfs_path *p;
1254
1255 p = alloc_path_for_send();
1256 if (!p)
1257 return -ENOMEM;
1258
1259 fs_path_reset(path);
1260
1261 key.objectid = ino;
1262 key.type = BTRFS_INODE_REF_KEY;
1263 key.offset = 0;
1264
1265 ret = btrfs_search_slot_for_read(root, &key, p, 1, 0);
1266 if (ret < 0)
1267 goto out;
1268 if (ret) {
1269 ret = 1;
1270 goto out;
1271 }
1272 btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]);
1273 if (found_key.objectid != ino ||
1274 (found_key.type != BTRFS_INODE_REF_KEY &&
1275 found_key.type != BTRFS_INODE_EXTREF_KEY)) {
1276 ret = -ENOENT;
1277 goto out;
1278 }
1279
1280 ret = iterate_inode_ref(root, p, &found_key, 1,
1281 __copy_first_ref, path);
1282 if (ret < 0)
1283 goto out;
1284 ret = 0;
1285
1286 out:
1287 btrfs_free_path(p);
1288 return ret;
1289 }
1290
1291 struct backref_ctx {
1292 struct send_ctx *sctx;
1293
1294 /* number of total found references */
1295 u64 found;
1296
1297 /*
1298 * used for clones found in send_root. clones found behind cur_objectid
1299 * and cur_offset are not considered as allowed clones.
1300 */
1301 u64 cur_objectid;
1302 u64 cur_offset;
1303
1304 /* may be truncated in case it's the last extent in a file */
1305 u64 extent_len;
1306
1307 /* The bytenr the file extent item we are processing refers to. */
1308 u64 bytenr;
1309 /* The owner (root id) of the data backref for the current extent. */
1310 u64 backref_owner;
1311 /* The offset of the data backref for the current extent. */
1312 u64 backref_offset;
1313 };
1314
1315 static int __clone_root_cmp_bsearch(const void *key, const void *elt)
1316 {
1317 u64 root = (u64)(uintptr_t)key;
1318 const struct clone_root *cr = elt;
1319
1320 if (root < btrfs_root_id(cr->root))
1321 return -1;
1322 if (root > btrfs_root_id(cr->root))
1323 return 1;
1324 return 0;
1325 }
1326
1327 static int __clone_root_cmp_sort(const void *e1, const void *e2)
1328 {
1329 const struct clone_root *cr1 = e1;
1330 const struct clone_root *cr2 = e2;
1331
1332 if (btrfs_root_id(cr1->root) < btrfs_root_id(cr2->root))
1333 return -1;
1334 if (btrfs_root_id(cr1->root) > btrfs_root_id(cr2->root))
1335 return 1;
1336 return 0;
1337 }
1338
1339 /*
1340 * Called for every backref that is found for the current extent.
1341 * Results are collected in sctx->clone_roots->ino/offset.
1342 */
1343 static int iterate_backrefs(u64 ino, u64 offset, u64 num_bytes, u64 root_id,
1344 void *ctx_)
1345 {
1346 struct backref_ctx *bctx = ctx_;
1347 struct clone_root *clone_root;
1348
1349 /* First check if the root is in the list of accepted clone sources */
1350 clone_root = bsearch((void *)(uintptr_t)root_id, bctx->sctx->clone_roots,
1351 bctx->sctx->clone_roots_cnt,
1352 sizeof(struct clone_root),
1353 __clone_root_cmp_bsearch);
1354 if (!clone_root)
1355 return 0;
1356
1357 /* This is our own reference, bail out as we can't clone from it. */
1358 if (clone_root->root == bctx->sctx->send_root &&
1359 ino == bctx->cur_objectid &&
1360 offset == bctx->cur_offset)
1361 return 0;
1362
1363 /*
1364 * Make sure we don't consider clones from send_root that are
1365 * behind the current inode/offset.
1366 */
1367 if (clone_root->root == bctx->sctx->send_root) {
1368 /*
1369 * If the source inode was not yet processed we can't issue a
1370 * clone operation, as the source extent does not exist yet at
1371 * the destination of the stream.
1372 */
1373 if (ino > bctx->cur_objectid)
1374 return 0;
1375 /*
1376 * We clone from the inode currently being sent as long as the
1377 * source extent is already processed, otherwise we could try
1378 * to clone from an extent that does not exist yet at the
1379 * destination of the stream.
1380 */
1381 if (ino == bctx->cur_objectid &&
1382 offset + bctx->extent_len >
1383 bctx->sctx->cur_inode_next_write_offset)
1384 return 0;
1385 }
1386
1387 bctx->found++;
1388 clone_root->found_ref = true;
1389
1390 /*
1391 * If the given backref refers to a file extent item with a larger
1392 * number of bytes than what we found before, use the new one so that
1393 * we clone more optimally and end up doing less writes and getting
1394 * less exclusive, non-shared extents at the destination.
1395 */
1396 if (num_bytes > clone_root->num_bytes) {
1397 clone_root->ino = ino;
1398 clone_root->offset = offset;
1399 clone_root->num_bytes = num_bytes;
1400
1401 /*
1402 * Found a perfect candidate, so there's no need to continue
1403 * backref walking.
1404 */
1405 if (num_bytes >= bctx->extent_len)
1406 return BTRFS_ITERATE_EXTENT_INODES_STOP;
1407 }
1408
1409 return 0;
1410 }
1411
1412 static bool lookup_backref_cache(u64 leaf_bytenr, void *ctx,
1413 const u64 **root_ids_ret, int *root_count_ret)
1414 {
1415 struct backref_ctx *bctx = ctx;
1416 struct send_ctx *sctx = bctx->sctx;
1417 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
1418 const u64 key = leaf_bytenr >> fs_info->sectorsize_bits;
1419 struct btrfs_lru_cache_entry *raw_entry;
1420 struct backref_cache_entry *entry;
1421
1422 if (sctx->backref_cache.size == 0)
1423 return false;
1424
1425 /*
1426 * If relocation happened since we first filled the cache, then we must
1427 * empty the cache and can not use it, because even though we operate on
1428 * read-only roots, their leaves and nodes may have been reallocated and
1429 * now be used for different nodes/leaves of the same tree or some other
1430 * tree.
1431 *
1432 * We are called from iterate_extent_inodes() while either holding a
1433 * transaction handle or holding fs_info->commit_root_sem, so no need
1434 * to take any lock here.
1435 */
1436 if (fs_info->last_reloc_trans > sctx->backref_cache_last_reloc_trans) {
1437 btrfs_lru_cache_clear(&sctx->backref_cache);
1438 return false;
1439 }
1440
1441 raw_entry = btrfs_lru_cache_lookup(&sctx->backref_cache, key, 0);
1442 if (!raw_entry)
1443 return false;
1444
1445 entry = container_of(raw_entry, struct backref_cache_entry, entry);
1446 *root_ids_ret = entry->root_ids;
1447 *root_count_ret = entry->num_roots;
1448
1449 return true;
1450 }
1451
1452 static void store_backref_cache(u64 leaf_bytenr, const struct ulist *root_ids,
1453 void *ctx)
1454 {
1455 struct backref_ctx *bctx = ctx;
1456 struct send_ctx *sctx = bctx->sctx;
1457 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
1458 struct backref_cache_entry *new_entry;
1459 struct ulist_iterator uiter;
1460 struct ulist_node *node;
1461 int ret;
1462
1463 /*
1464 * We're called while holding a transaction handle or while holding
1465 * fs_info->commit_root_sem (at iterate_extent_inodes()), so must do a
1466 * NOFS allocation.
1467 */
1468 new_entry = kmalloc(sizeof(struct backref_cache_entry), GFP_NOFS);
1469 /* No worries, cache is optional. */
1470 if (!new_entry)
1471 return;
1472
1473 new_entry->entry.key = leaf_bytenr >> fs_info->sectorsize_bits;
1474 new_entry->entry.gen = 0;
1475 new_entry->num_roots = 0;
1476 ULIST_ITER_INIT(&uiter);
1477 while ((node = ulist_next(root_ids, &uiter)) != NULL) {
1478 const u64 root_id = node->val;
1479 struct clone_root *root;
1480
1481 root = bsearch((void *)(uintptr_t)root_id, sctx->clone_roots,
1482 sctx->clone_roots_cnt, sizeof(struct clone_root),
1483 __clone_root_cmp_bsearch);
1484 if (!root)
1485 continue;
1486
1487 /* Too many roots, just exit, no worries as caching is optional. */
1488 if (new_entry->num_roots >= SEND_MAX_BACKREF_CACHE_ROOTS) {
1489 kfree(new_entry);
1490 return;
1491 }
1492
1493 new_entry->root_ids[new_entry->num_roots] = root_id;
1494 new_entry->num_roots++;
1495 }
1496
1497 /*
1498 * We may have not added any roots to the new cache entry, which means
1499 * none of the roots is part of the list of roots from which we are
1500 * allowed to clone. Cache the new entry as it's still useful to avoid
1501 * backref walking to determine which roots have a path to the leaf.
1502 *
1503 * Also use GFP_NOFS because we're called while holding a transaction
1504 * handle or while holding fs_info->commit_root_sem.
1505 */
1506 ret = btrfs_lru_cache_store(&sctx->backref_cache, &new_entry->entry,
1507 GFP_NOFS);
1508 ASSERT(ret == 0 || ret == -ENOMEM);
1509 if (ret) {
1510 /* Caching is optional, no worries. */
1511 kfree(new_entry);
1512 return;
1513 }
1514
1515 /*
1516 * We are called from iterate_extent_inodes() while either holding a
1517 * transaction handle or holding fs_info->commit_root_sem, so no need
1518 * to take any lock here.
1519 */
1520 if (sctx->backref_cache.size == 1)
1521 sctx->backref_cache_last_reloc_trans = fs_info->last_reloc_trans;
1522 }
1523
1524 static int check_extent_item(u64 bytenr, const struct btrfs_extent_item *ei,
1525 const struct extent_buffer *leaf, void *ctx)
1526 {
1527 const u64 refs = btrfs_extent_refs(leaf, ei);
1528 const struct backref_ctx *bctx = ctx;
1529 const struct send_ctx *sctx = bctx->sctx;
1530
1531 if (bytenr == bctx->bytenr) {
1532 const u64 flags = btrfs_extent_flags(leaf, ei);
1533
1534 if (WARN_ON(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
1535 return -EUCLEAN;
1536
1537 /*
1538 * If we have only one reference and only the send root as a
1539 * clone source - meaning no clone roots were given in the
1540 * struct btrfs_ioctl_send_args passed to the send ioctl - then
1541 * it's our reference and there's no point in doing backref
1542 * walking which is expensive, so exit early.
1543 */
1544 if (refs == 1 && sctx->clone_roots_cnt == 1)
1545 return -ENOENT;
1546 }
1547
1548 /*
1549 * Backreference walking (iterate_extent_inodes() below) is currently
1550 * too expensive when an extent has a large number of references, both
1551 * in time spent and used memory. So for now just fallback to write
1552 * operations instead of clone operations when an extent has more than
1553 * a certain amount of references.
1554 */
1555 if (refs > SEND_MAX_EXTENT_REFS)
1556 return -ENOENT;
1557
1558 return 0;
1559 }
1560
1561 static bool skip_self_data_ref(u64 root, u64 ino, u64 offset, void *ctx)
1562 {
1563 const struct backref_ctx *bctx = ctx;
1564
1565 if (ino == bctx->cur_objectid &&
1566 root == bctx->backref_owner &&
1567 offset == bctx->backref_offset)
1568 return true;
1569
1570 return false;
1571 }
1572
1573 /*
1574 * Given an inode, offset and extent item, it finds a good clone for a clone
1575 * instruction. Returns -ENOENT when none could be found. The function makes
1576 * sure that the returned clone is usable at the point where sending is at the
1577 * moment. This means, that no clones are accepted which lie behind the current
1578 * inode+offset.
1579 *
1580 * path must point to the extent item when called.
1581 */
1582 static int find_extent_clone(struct send_ctx *sctx,
1583 struct btrfs_path *path,
1584 u64 ino, u64 data_offset,
1585 u64 ino_size,
1586 struct clone_root **found)
1587 {
1588 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
1589 int ret;
1590 int extent_type;
1591 u64 logical;
1592 u64 disk_byte;
1593 u64 num_bytes;
1594 struct btrfs_file_extent_item *fi;
1595 struct extent_buffer *eb = path->nodes[0];
1596 struct backref_ctx backref_ctx = { 0 };
1597 struct btrfs_backref_walk_ctx backref_walk_ctx = { 0 };
1598 struct clone_root *cur_clone_root;
1599 int compressed;
1600 u32 i;
1601
1602 /*
1603 * With fallocate we can get prealloc extents beyond the inode's i_size,
1604 * so we don't do anything here because clone operations can not clone
1605 * to a range beyond i_size without increasing the i_size of the
1606 * destination inode.
1607 */
1608 if (data_offset >= ino_size)
1609 return 0;
1610
1611 fi = btrfs_item_ptr(eb, path->slots[0], struct btrfs_file_extent_item);
1612 extent_type = btrfs_file_extent_type(eb, fi);
1613 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
1614 return -ENOENT;
1615
1616 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
1617 if (disk_byte == 0)
1618 return -ENOENT;
1619
1620 compressed = btrfs_file_extent_compression(eb, fi);
1621 num_bytes = btrfs_file_extent_num_bytes(eb, fi);
1622 logical = disk_byte + btrfs_file_extent_offset(eb, fi);
1623
1624 /*
1625 * Setup the clone roots.
1626 */
1627 for (i = 0; i < sctx->clone_roots_cnt; i++) {
1628 cur_clone_root = sctx->clone_roots + i;
1629 cur_clone_root->ino = (u64)-1;
1630 cur_clone_root->offset = 0;
1631 cur_clone_root->num_bytes = 0;
1632 cur_clone_root->found_ref = false;
1633 }
1634
1635 backref_ctx.sctx = sctx;
1636 backref_ctx.cur_objectid = ino;
1637 backref_ctx.cur_offset = data_offset;
1638 backref_ctx.bytenr = disk_byte;
1639 /*
1640 * Use the header owner and not the send root's id, because in case of a
1641 * snapshot we can have shared subtrees.
1642 */
1643 backref_ctx.backref_owner = btrfs_header_owner(eb);
1644 backref_ctx.backref_offset = data_offset - btrfs_file_extent_offset(eb, fi);
1645
1646 /*
1647 * The last extent of a file may be too large due to page alignment.
1648 * We need to adjust extent_len in this case so that the checks in
1649 * iterate_backrefs() work.
1650 */
1651 if (data_offset + num_bytes >= ino_size)
1652 backref_ctx.extent_len = ino_size - data_offset;
1653 else
1654 backref_ctx.extent_len = num_bytes;
1655
1656 /*
1657 * Now collect all backrefs.
1658 */
1659 backref_walk_ctx.bytenr = disk_byte;
1660 if (compressed == BTRFS_COMPRESS_NONE)
1661 backref_walk_ctx.extent_item_pos = btrfs_file_extent_offset(eb, fi);
1662 backref_walk_ctx.fs_info = fs_info;
1663 backref_walk_ctx.cache_lookup = lookup_backref_cache;
1664 backref_walk_ctx.cache_store = store_backref_cache;
1665 backref_walk_ctx.indirect_ref_iterator = iterate_backrefs;
1666 backref_walk_ctx.check_extent_item = check_extent_item;
1667 backref_walk_ctx.user_ctx = &backref_ctx;
1668
1669 /*
1670 * If have a single clone root, then it's the send root and we can tell
1671 * the backref walking code to skip our own backref and not resolve it,
1672 * since we can not use it for cloning - the source and destination
1673 * ranges can't overlap and in case the leaf is shared through a subtree
1674 * due to snapshots, we can't use those other roots since they are not
1675 * in the list of clone roots.
1676 */
1677 if (sctx->clone_roots_cnt == 1)
1678 backref_walk_ctx.skip_data_ref = skip_self_data_ref;
1679
1680 ret = iterate_extent_inodes(&backref_walk_ctx, true, iterate_backrefs,
1681 &backref_ctx);
1682 if (ret < 0)
1683 return ret;
1684
1685 down_read(&fs_info->commit_root_sem);
1686 if (fs_info->last_reloc_trans > sctx->last_reloc_trans) {
1687 /*
1688 * A transaction commit for a transaction in which block group
1689 * relocation was done just happened.
1690 * The disk_bytenr of the file extent item we processed is
1691 * possibly stale, referring to the extent's location before
1692 * relocation. So act as if we haven't found any clone sources
1693 * and fallback to write commands, which will read the correct
1694 * data from the new extent location. Otherwise we will fail
1695 * below because we haven't found our own back reference or we
1696 * could be getting incorrect sources in case the old extent
1697 * was already reallocated after the relocation.
1698 */
1699 up_read(&fs_info->commit_root_sem);
1700 return -ENOENT;
1701 }
1702 up_read(&fs_info->commit_root_sem);
1703
1704 btrfs_debug(fs_info,
1705 "find_extent_clone: data_offset=%llu, ino=%llu, num_bytes=%llu, logical=%llu",
1706 data_offset, ino, num_bytes, logical);
1707
1708 if (!backref_ctx.found) {
1709 btrfs_debug(fs_info, "no clones found");
1710 return -ENOENT;
1711 }
1712
1713 cur_clone_root = NULL;
1714 for (i = 0; i < sctx->clone_roots_cnt; i++) {
1715 struct clone_root *clone_root = &sctx->clone_roots[i];
1716
1717 if (!clone_root->found_ref)
1718 continue;
1719
1720 /*
1721 * Choose the root from which we can clone more bytes, to
1722 * minimize write operations and therefore have more extent
1723 * sharing at the destination (the same as in the source).
1724 */
1725 if (!cur_clone_root ||
1726 clone_root->num_bytes > cur_clone_root->num_bytes) {
1727 cur_clone_root = clone_root;
1728
1729 /*
1730 * We found an optimal clone candidate (any inode from
1731 * any root is fine), so we're done.
1732 */
1733 if (clone_root->num_bytes >= backref_ctx.extent_len)
1734 break;
1735 }
1736 }
1737
1738 if (cur_clone_root) {
1739 *found = cur_clone_root;
1740 ret = 0;
1741 } else {
1742 ret = -ENOENT;
1743 }
1744
1745 return ret;
1746 }
1747
1748 static int read_symlink(struct btrfs_root *root,
1749 u64 ino,
1750 struct fs_path *dest)
1751 {
1752 int ret;
1753 struct btrfs_path *path;
1754 struct btrfs_key key;
1755 struct btrfs_file_extent_item *ei;
1756 u8 type;
1757 u8 compression;
1758 unsigned long off;
1759 int len;
1760
1761 path = alloc_path_for_send();
1762 if (!path)
1763 return -ENOMEM;
1764
1765 key.objectid = ino;
1766 key.type = BTRFS_EXTENT_DATA_KEY;
1767 key.offset = 0;
1768 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1769 if (ret < 0)
1770 goto out;
1771 if (ret) {
1772 /*
1773 * An empty symlink inode. Can happen in rare error paths when
1774 * creating a symlink (transaction committed before the inode
1775 * eviction handler removed the symlink inode items and a crash
1776 * happened in between or the subvol was snapshoted in between).
1777 * Print an informative message to dmesg/syslog so that the user
1778 * can delete the symlink.
1779 */
1780 btrfs_err(root->fs_info,
1781 "Found empty symlink inode %llu at root %llu",
1782 ino, btrfs_root_id(root));
1783 ret = -EIO;
1784 goto out;
1785 }
1786
1787 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
1788 struct btrfs_file_extent_item);
1789 type = btrfs_file_extent_type(path->nodes[0], ei);
1790 if (unlikely(type != BTRFS_FILE_EXTENT_INLINE)) {
1791 ret = -EUCLEAN;
1792 btrfs_crit(root->fs_info,
1793 "send: found symlink extent that is not inline, ino %llu root %llu extent type %d",
1794 ino, btrfs_root_id(root), type);
1795 goto out;
1796 }
1797 compression = btrfs_file_extent_compression(path->nodes[0], ei);
1798 if (unlikely(compression != BTRFS_COMPRESS_NONE)) {
1799 ret = -EUCLEAN;
1800 btrfs_crit(root->fs_info,
1801 "send: found symlink extent with compression, ino %llu root %llu compression type %d",
1802 ino, btrfs_root_id(root), compression);
1803 goto out;
1804 }
1805
1806 off = btrfs_file_extent_inline_start(ei);
1807 len = btrfs_file_extent_ram_bytes(path->nodes[0], ei);
1808
1809 ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len);
1810
1811 out:
1812 btrfs_free_path(path);
1813 return ret;
1814 }
1815
1816 /*
1817 * Helper function to generate a file name that is unique in the root of
1818 * send_root and parent_root. This is used to generate names for orphan inodes.
1819 */
1820 static int gen_unique_name(struct send_ctx *sctx,
1821 u64 ino, u64 gen,
1822 struct fs_path *dest)
1823 {
1824 int ret = 0;
1825 struct btrfs_path *path;
1826 struct btrfs_dir_item *di;
1827 char tmp[64];
1828 int len;
1829 u64 idx = 0;
1830
1831 path = alloc_path_for_send();
1832 if (!path)
1833 return -ENOMEM;
1834
1835 while (1) {
1836 struct fscrypt_str tmp_name;
1837
1838 len = snprintf(tmp, sizeof(tmp), "o%llu-%llu-%llu",
1839 ino, gen, idx);
1840 ASSERT(len < sizeof(tmp));
1841 tmp_name.name = tmp;
1842 tmp_name.len = strlen(tmp);
1843
1844 di = btrfs_lookup_dir_item(NULL, sctx->send_root,
1845 path, BTRFS_FIRST_FREE_OBJECTID,
1846 &tmp_name, 0);
1847 btrfs_release_path(path);
1848 if (IS_ERR(di)) {
1849 ret = PTR_ERR(di);
1850 goto out;
1851 }
1852 if (di) {
1853 /* not unique, try again */
1854 idx++;
1855 continue;
1856 }
1857
1858 if (!sctx->parent_root) {
1859 /* unique */
1860 ret = 0;
1861 break;
1862 }
1863
1864 di = btrfs_lookup_dir_item(NULL, sctx->parent_root,
1865 path, BTRFS_FIRST_FREE_OBJECTID,
1866 &tmp_name, 0);
1867 btrfs_release_path(path);
1868 if (IS_ERR(di)) {
1869 ret = PTR_ERR(di);
1870 goto out;
1871 }
1872 if (di) {
1873 /* not unique, try again */
1874 idx++;
1875 continue;
1876 }
1877 /* unique */
1878 break;
1879 }
1880
1881 ret = fs_path_add(dest, tmp, strlen(tmp));
1882
1883 out:
1884 btrfs_free_path(path);
1885 return ret;
1886 }
1887
1888 enum inode_state {
1889 inode_state_no_change,
1890 inode_state_will_create,
1891 inode_state_did_create,
1892 inode_state_will_delete,
1893 inode_state_did_delete,
1894 };
1895
1896 static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen,
1897 u64 *send_gen, u64 *parent_gen)
1898 {
1899 int ret;
1900 int left_ret;
1901 int right_ret;
1902 u64 left_gen;
1903 u64 right_gen = 0;
1904 struct btrfs_inode_info info;
1905
1906 ret = get_inode_info(sctx->send_root, ino, &info);
1907 if (ret < 0 && ret != -ENOENT)
1908 goto out;
1909 left_ret = (info.nlink == 0) ? -ENOENT : ret;
1910 left_gen = info.gen;
1911 if (send_gen)
1912 *send_gen = ((left_ret == -ENOENT) ? 0 : info.gen);
1913
1914 if (!sctx->parent_root) {
1915 right_ret = -ENOENT;
1916 } else {
1917 ret = get_inode_info(sctx->parent_root, ino, &info);
1918 if (ret < 0 && ret != -ENOENT)
1919 goto out;
1920 right_ret = (info.nlink == 0) ? -ENOENT : ret;
1921 right_gen = info.gen;
1922 if (parent_gen)
1923 *parent_gen = ((right_ret == -ENOENT) ? 0 : info.gen);
1924 }
1925
1926 if (!left_ret && !right_ret) {
1927 if (left_gen == gen && right_gen == gen) {
1928 ret = inode_state_no_change;
1929 } else if (left_gen == gen) {
1930 if (ino < sctx->send_progress)
1931 ret = inode_state_did_create;
1932 else
1933 ret = inode_state_will_create;
1934 } else if (right_gen == gen) {
1935 if (ino < sctx->send_progress)
1936 ret = inode_state_did_delete;
1937 else
1938 ret = inode_state_will_delete;
1939 } else {
1940 ret = -ENOENT;
1941 }
1942 } else if (!left_ret) {
1943 if (left_gen == gen) {
1944 if (ino < sctx->send_progress)
1945 ret = inode_state_did_create;
1946 else
1947 ret = inode_state_will_create;
1948 } else {
1949 ret = -ENOENT;
1950 }
1951 } else if (!right_ret) {
1952 if (right_gen == gen) {
1953 if (ino < sctx->send_progress)
1954 ret = inode_state_did_delete;
1955 else
1956 ret = inode_state_will_delete;
1957 } else {
1958 ret = -ENOENT;
1959 }
1960 } else {
1961 ret = -ENOENT;
1962 }
1963
1964 out:
1965 return ret;
1966 }
1967
1968 static int is_inode_existent(struct send_ctx *sctx, u64 ino, u64 gen,
1969 u64 *send_gen, u64 *parent_gen)
1970 {
1971 int ret;
1972
1973 if (ino == BTRFS_FIRST_FREE_OBJECTID)
1974 return 1;
1975
1976 ret = get_cur_inode_state(sctx, ino, gen, send_gen, parent_gen);
1977 if (ret < 0)
1978 goto out;
1979
1980 if (ret == inode_state_no_change ||
1981 ret == inode_state_did_create ||
1982 ret == inode_state_will_delete)
1983 ret = 1;
1984 else
1985 ret = 0;
1986
1987 out:
1988 return ret;
1989 }
1990
1991 /*
1992 * Helper function to lookup a dir item in a dir.
1993 */
1994 static int lookup_dir_item_inode(struct btrfs_root *root,
1995 u64 dir, const char *name, int name_len,
1996 u64 *found_inode)
1997 {
1998 int ret = 0;
1999 struct btrfs_dir_item *di;
2000 struct btrfs_key key;
2001 struct btrfs_path *path;
2002 struct fscrypt_str name_str = FSTR_INIT((char *)name, name_len);
2003
2004 path = alloc_path_for_send();
2005 if (!path)
2006 return -ENOMEM;
2007
2008 di = btrfs_lookup_dir_item(NULL, root, path, dir, &name_str, 0);
2009 if (IS_ERR_OR_NULL(di)) {
2010 ret = di ? PTR_ERR(di) : -ENOENT;
2011 goto out;
2012 }
2013 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
2014 if (key.type == BTRFS_ROOT_ITEM_KEY) {
2015 ret = -ENOENT;
2016 goto out;
2017 }
2018 *found_inode = key.objectid;
2019
2020 out:
2021 btrfs_free_path(path);
2022 return ret;
2023 }
2024
2025 /*
2026 * Looks up the first btrfs_inode_ref of a given ino. It returns the parent dir,
2027 * generation of the parent dir and the name of the dir entry.
2028 */
2029 static int get_first_ref(struct btrfs_root *root, u64 ino,
2030 u64 *dir, u64 *dir_gen, struct fs_path *name)
2031 {
2032 int ret;
2033 struct btrfs_key key;
2034 struct btrfs_key found_key;
2035 struct btrfs_path *path;
2036 int len;
2037 u64 parent_dir;
2038
2039 path = alloc_path_for_send();
2040 if (!path)
2041 return -ENOMEM;
2042
2043 key.objectid = ino;
2044 key.type = BTRFS_INODE_REF_KEY;
2045 key.offset = 0;
2046
2047 ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
2048 if (ret < 0)
2049 goto out;
2050 if (!ret)
2051 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2052 path->slots[0]);
2053 if (ret || found_key.objectid != ino ||
2054 (found_key.type != BTRFS_INODE_REF_KEY &&
2055 found_key.type != BTRFS_INODE_EXTREF_KEY)) {
2056 ret = -ENOENT;
2057 goto out;
2058 }
2059
2060 if (found_key.type == BTRFS_INODE_REF_KEY) {
2061 struct btrfs_inode_ref *iref;
2062 iref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2063 struct btrfs_inode_ref);
2064 len = btrfs_inode_ref_name_len(path->nodes[0], iref);
2065 ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
2066 (unsigned long)(iref + 1),
2067 len);
2068 parent_dir = found_key.offset;
2069 } else {
2070 struct btrfs_inode_extref *extref;
2071 extref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2072 struct btrfs_inode_extref);
2073 len = btrfs_inode_extref_name_len(path->nodes[0], extref);
2074 ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
2075 (unsigned long)&extref->name, len);
2076 parent_dir = btrfs_inode_extref_parent(path->nodes[0], extref);
2077 }
2078 if (ret < 0)
2079 goto out;
2080 btrfs_release_path(path);
2081
2082 if (dir_gen) {
2083 ret = get_inode_gen(root, parent_dir, dir_gen);
2084 if (ret < 0)
2085 goto out;
2086 }
2087
2088 *dir = parent_dir;
2089
2090 out:
2091 btrfs_free_path(path);
2092 return ret;
2093 }
2094
2095 static int is_first_ref(struct btrfs_root *root,
2096 u64 ino, u64 dir,
2097 const char *name, int name_len)
2098 {
2099 int ret;
2100 struct fs_path *tmp_name;
2101 u64 tmp_dir;
2102
2103 tmp_name = fs_path_alloc();
2104 if (!tmp_name)
2105 return -ENOMEM;
2106
2107 ret = get_first_ref(root, ino, &tmp_dir, NULL, tmp_name);
2108 if (ret < 0)
2109 goto out;
2110
2111 if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) {
2112 ret = 0;
2113 goto out;
2114 }
2115
2116 ret = !memcmp(tmp_name->start, name, name_len);
2117
2118 out:
2119 fs_path_free(tmp_name);
2120 return ret;
2121 }
2122
2123 /*
2124 * Used by process_recorded_refs to determine if a new ref would overwrite an
2125 * already existing ref. In case it detects an overwrite, it returns the
2126 * inode/gen in who_ino/who_gen.
2127 * When an overwrite is detected, process_recorded_refs does proper orphanizing
2128 * to make sure later references to the overwritten inode are possible.
2129 * Orphanizing is however only required for the first ref of an inode.
2130 * process_recorded_refs does an additional is_first_ref check to see if
2131 * orphanizing is really required.
2132 */
2133 static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
2134 const char *name, int name_len,
2135 u64 *who_ino, u64 *who_gen, u64 *who_mode)
2136 {
2137 int ret;
2138 u64 parent_root_dir_gen;
2139 u64 other_inode = 0;
2140 struct btrfs_inode_info info;
2141
2142 if (!sctx->parent_root)
2143 return 0;
2144
2145 ret = is_inode_existent(sctx, dir, dir_gen, NULL, &parent_root_dir_gen);
2146 if (ret <= 0)
2147 return 0;
2148
2149 /*
2150 * If we have a parent root we need to verify that the parent dir was
2151 * not deleted and then re-created, if it was then we have no overwrite
2152 * and we can just unlink this entry.
2153 *
2154 * @parent_root_dir_gen was set to 0 if the inode does not exist in the
2155 * parent root.
2156 */
2157 if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID &&
2158 parent_root_dir_gen != dir_gen)
2159 return 0;
2160
2161 ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
2162 &other_inode);
2163 if (ret == -ENOENT)
2164 return 0;
2165 else if (ret < 0)
2166 return ret;
2167
2168 /*
2169 * Check if the overwritten ref was already processed. If yes, the ref
2170 * was already unlinked/moved, so we can safely assume that we will not
2171 * overwrite anything at this point in time.
2172 */
2173 if (other_inode > sctx->send_progress ||
2174 is_waiting_for_move(sctx, other_inode)) {
2175 ret = get_inode_info(sctx->parent_root, other_inode, &info);
2176 if (ret < 0)
2177 return ret;
2178
2179 *who_ino = other_inode;
2180 *who_gen = info.gen;
2181 *who_mode = info.mode;
2182 return 1;
2183 }
2184
2185 return 0;
2186 }
2187
2188 /*
2189 * Checks if the ref was overwritten by an already processed inode. This is
2190 * used by __get_cur_name_and_parent to find out if the ref was orphanized and
2191 * thus the orphan name needs be used.
2192 * process_recorded_refs also uses it to avoid unlinking of refs that were
2193 * overwritten.
2194 */
2195 static int did_overwrite_ref(struct send_ctx *sctx,
2196 u64 dir, u64 dir_gen,
2197 u64 ino, u64 ino_gen,
2198 const char *name, int name_len)
2199 {
2200 int ret;
2201 u64 ow_inode;
2202 u64 ow_gen = 0;
2203 u64 send_root_dir_gen;
2204
2205 if (!sctx->parent_root)
2206 return 0;
2207
2208 ret = is_inode_existent(sctx, dir, dir_gen, &send_root_dir_gen, NULL);
2209 if (ret <= 0)
2210 return ret;
2211
2212 /*
2213 * @send_root_dir_gen was set to 0 if the inode does not exist in the
2214 * send root.
2215 */
2216 if (dir != BTRFS_FIRST_FREE_OBJECTID && send_root_dir_gen != dir_gen)
2217 return 0;
2218
2219 /* check if the ref was overwritten by another ref */
2220 ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
2221 &ow_inode);
2222 if (ret == -ENOENT) {
2223 /* was never and will never be overwritten */
2224 return 0;
2225 } else if (ret < 0) {
2226 return ret;
2227 }
2228
2229 if (ow_inode == ino) {
2230 ret = get_inode_gen(sctx->send_root, ow_inode, &ow_gen);
2231 if (ret < 0)
2232 return ret;
2233
2234 /* It's the same inode, so no overwrite happened. */
2235 if (ow_gen == ino_gen)
2236 return 0;
2237 }
2238
2239 /*
2240 * We know that it is or will be overwritten. Check this now.
2241 * The current inode being processed might have been the one that caused
2242 * inode 'ino' to be orphanized, therefore check if ow_inode matches
2243 * the current inode being processed.
2244 */
2245 if (ow_inode < sctx->send_progress)
2246 return 1;
2247
2248 if (ino != sctx->cur_ino && ow_inode == sctx->cur_ino) {
2249 if (ow_gen == 0) {
2250 ret = get_inode_gen(sctx->send_root, ow_inode, &ow_gen);
2251 if (ret < 0)
2252 return ret;
2253 }
2254 if (ow_gen == sctx->cur_inode_gen)
2255 return 1;
2256 }
2257
2258 return 0;
2259 }
2260
2261 /*
2262 * Same as did_overwrite_ref, but also checks if it is the first ref of an inode
2263 * that got overwritten. This is used by process_recorded_refs to determine
2264 * if it has to use the path as returned by get_cur_path or the orphan name.
2265 */
2266 static int did_overwrite_first_ref(struct send_ctx *sctx, u64 ino, u64 gen)
2267 {
2268 int ret = 0;
2269 struct fs_path *name = NULL;
2270 u64 dir;
2271 u64 dir_gen;
2272
2273 if (!sctx->parent_root)
2274 goto out;
2275
2276 name = fs_path_alloc();
2277 if (!name)
2278 return -ENOMEM;
2279
2280 ret = get_first_ref(sctx->parent_root, ino, &dir, &dir_gen, name);
2281 if (ret < 0)
2282 goto out;
2283
2284 ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen,
2285 name->start, fs_path_len(name));
2286
2287 out:
2288 fs_path_free(name);
2289 return ret;
2290 }
2291
2292 static inline struct name_cache_entry *name_cache_search(struct send_ctx *sctx,
2293 u64 ino, u64 gen)
2294 {
2295 struct btrfs_lru_cache_entry *entry;
2296
2297 entry = btrfs_lru_cache_lookup(&sctx->name_cache, ino, gen);
2298 if (!entry)
2299 return NULL;
2300
2301 return container_of(entry, struct name_cache_entry, entry);
2302 }
2303
2304 /*
2305 * Used by get_cur_path for each ref up to the root.
2306 * Returns 0 if it succeeded.
2307 * Returns 1 if the inode is not existent or got overwritten. In that case, the
2308 * name is an orphan name. This instructs get_cur_path to stop iterating. If 1
2309 * is returned, parent_ino/parent_gen are not guaranteed to be valid.
2310 * Returns <0 in case of error.
2311 */
2312 static int __get_cur_name_and_parent(struct send_ctx *sctx,
2313 u64 ino, u64 gen,
2314 u64 *parent_ino,
2315 u64 *parent_gen,
2316 struct fs_path *dest)
2317 {
2318 int ret;
2319 int nce_ret;
2320 struct name_cache_entry *nce;
2321
2322 /*
2323 * First check if we already did a call to this function with the same
2324 * ino/gen. If yes, check if the cache entry is still up-to-date. If yes
2325 * return the cached result.
2326 */
2327 nce = name_cache_search(sctx, ino, gen);
2328 if (nce) {
2329 if (ino < sctx->send_progress && nce->need_later_update) {
2330 btrfs_lru_cache_remove(&sctx->name_cache, &nce->entry);
2331 nce = NULL;
2332 } else {
2333 *parent_ino = nce->parent_ino;
2334 *parent_gen = nce->parent_gen;
2335 ret = fs_path_add(dest, nce->name, nce->name_len);
2336 if (ret < 0)
2337 goto out;
2338 ret = nce->ret;
2339 goto out;
2340 }
2341 }
2342
2343 /*
2344 * If the inode is not existent yet, add the orphan name and return 1.
2345 * This should only happen for the parent dir that we determine in
2346 * record_new_ref_if_needed().
2347 */
2348 ret = is_inode_existent(sctx, ino, gen, NULL, NULL);
2349 if (ret < 0)
2350 goto out;
2351
2352 if (!ret) {
2353 ret = gen_unique_name(sctx, ino, gen, dest);
2354 if (ret < 0)
2355 goto out;
2356 ret = 1;
2357 goto out_cache;
2358 }
2359
2360 /*
2361 * Depending on whether the inode was already processed or not, use
2362 * send_root or parent_root for ref lookup.
2363 */
2364 if (ino < sctx->send_progress)
2365 ret = get_first_ref(sctx->send_root, ino,
2366 parent_ino, parent_gen, dest);
2367 else
2368 ret = get_first_ref(sctx->parent_root, ino,
2369 parent_ino, parent_gen, dest);
2370 if (ret < 0)
2371 goto out;
2372
2373 /*
2374 * Check if the ref was overwritten by an inode's ref that was processed
2375 * earlier. If yes, treat as orphan and return 1.
2376 */
2377 ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen,
2378 dest->start, dest->end - dest->start);
2379 if (ret < 0)
2380 goto out;
2381 if (ret) {
2382 fs_path_reset(dest);
2383 ret = gen_unique_name(sctx, ino, gen, dest);
2384 if (ret < 0)
2385 goto out;
2386 ret = 1;
2387 }
2388
2389 out_cache:
2390 /*
2391 * Store the result of the lookup in the name cache.
2392 */
2393 nce = kmalloc(sizeof(*nce) + fs_path_len(dest), GFP_KERNEL);
2394 if (!nce) {
2395 ret = -ENOMEM;
2396 goto out;
2397 }
2398
2399 nce->entry.key = ino;
2400 nce->entry.gen = gen;
2401 nce->parent_ino = *parent_ino;
2402 nce->parent_gen = *parent_gen;
2403 nce->name_len = fs_path_len(dest);
2404 nce->ret = ret;
2405 memcpy(nce->name, dest->start, nce->name_len);
2406
2407 if (ino < sctx->send_progress)
2408 nce->need_later_update = 0;
2409 else
2410 nce->need_later_update = 1;
2411
2412 nce_ret = btrfs_lru_cache_store(&sctx->name_cache, &nce->entry, GFP_KERNEL);
2413 if (nce_ret < 0) {
2414 kfree(nce);
2415 ret = nce_ret;
2416 }
2417
2418 out:
2419 return ret;
2420 }
2421
2422 /*
2423 * Magic happens here. This function returns the first ref to an inode as it
2424 * would look like while receiving the stream at this point in time.
2425 * We walk the path up to the root. For every inode in between, we check if it
2426 * was already processed/sent. If yes, we continue with the parent as found
2427 * in send_root. If not, we continue with the parent as found in parent_root.
2428 * If we encounter an inode that was deleted at this point in time, we use the
2429 * inodes "orphan" name instead of the real name and stop. Same with new inodes
2430 * that were not created yet and overwritten inodes/refs.
2431 *
2432 * When do we have orphan inodes:
2433 * 1. When an inode is freshly created and thus no valid refs are available yet
2434 * 2. When a directory lost all it's refs (deleted) but still has dir items
2435 * inside which were not processed yet (pending for move/delete). If anyone
2436 * tried to get the path to the dir items, it would get a path inside that
2437 * orphan directory.
2438 * 3. When an inode is moved around or gets new links, it may overwrite the ref
2439 * of an unprocessed inode. If in that case the first ref would be
2440 * overwritten, the overwritten inode gets "orphanized". Later when we
2441 * process this overwritten inode, it is restored at a new place by moving
2442 * the orphan inode.
2443 *
2444 * sctx->send_progress tells this function at which point in time receiving
2445 * would be.
2446 */
2447 static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
2448 struct fs_path *dest)
2449 {
2450 int ret = 0;
2451 struct fs_path *name = NULL;
2452 u64 parent_inode = 0;
2453 u64 parent_gen = 0;
2454 int stop = 0;
2455
2456 name = fs_path_alloc();
2457 if (!name) {
2458 ret = -ENOMEM;
2459 goto out;
2460 }
2461
2462 dest->reversed = 1;
2463 fs_path_reset(dest);
2464
2465 while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) {
2466 struct waiting_dir_move *wdm;
2467
2468 fs_path_reset(name);
2469
2470 if (is_waiting_for_rm(sctx, ino, gen)) {
2471 ret = gen_unique_name(sctx, ino, gen, name);
2472 if (ret < 0)
2473 goto out;
2474 ret = fs_path_add_path(dest, name);
2475 break;
2476 }
2477
2478 wdm = get_waiting_dir_move(sctx, ino);
2479 if (wdm && wdm->orphanized) {
2480 ret = gen_unique_name(sctx, ino, gen, name);
2481 stop = 1;
2482 } else if (wdm) {
2483 ret = get_first_ref(sctx->parent_root, ino,
2484 &parent_inode, &parent_gen, name);
2485 } else {
2486 ret = __get_cur_name_and_parent(sctx, ino, gen,
2487 &parent_inode,
2488 &parent_gen, name);
2489 if (ret)
2490 stop = 1;
2491 }
2492
2493 if (ret < 0)
2494 goto out;
2495
2496 ret = fs_path_add_path(dest, name);
2497 if (ret < 0)
2498 goto out;
2499
2500 ino = parent_inode;
2501 gen = parent_gen;
2502 }
2503
2504 out:
2505 fs_path_free(name);
2506 if (!ret)
2507 fs_path_unreverse(dest);
2508 return ret;
2509 }
2510
2511 /*
2512 * Sends a BTRFS_SEND_C_SUBVOL command/item to userspace
2513 */
2514 static int send_subvol_begin(struct send_ctx *sctx)
2515 {
2516 int ret;
2517 struct btrfs_root *send_root = sctx->send_root;
2518 struct btrfs_root *parent_root = sctx->parent_root;
2519 struct btrfs_path *path;
2520 struct btrfs_key key;
2521 struct btrfs_root_ref *ref;
2522 struct extent_buffer *leaf;
2523 char *name = NULL;
2524 int namelen;
2525
2526 path = btrfs_alloc_path();
2527 if (!path)
2528 return -ENOMEM;
2529
2530 name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL);
2531 if (!name) {
2532 btrfs_free_path(path);
2533 return -ENOMEM;
2534 }
2535
2536 key.objectid = btrfs_root_id(send_root);
2537 key.type = BTRFS_ROOT_BACKREF_KEY;
2538 key.offset = 0;
2539
2540 ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root,
2541 &key, path, 1, 0);
2542 if (ret < 0)
2543 goto out;
2544 if (ret) {
2545 ret = -ENOENT;
2546 goto out;
2547 }
2548
2549 leaf = path->nodes[0];
2550 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2551 if (key.type != BTRFS_ROOT_BACKREF_KEY ||
2552 key.objectid != btrfs_root_id(send_root)) {
2553 ret = -ENOENT;
2554 goto out;
2555 }
2556 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
2557 namelen = btrfs_root_ref_name_len(leaf, ref);
2558 read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen);
2559 btrfs_release_path(path);
2560
2561 if (parent_root) {
2562 ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT);
2563 if (ret < 0)
2564 goto out;
2565 } else {
2566 ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL);
2567 if (ret < 0)
2568 goto out;
2569 }
2570
2571 TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen);
2572
2573 if (!btrfs_is_empty_uuid(sctx->send_root->root_item.received_uuid))
2574 TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
2575 sctx->send_root->root_item.received_uuid);
2576 else
2577 TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
2578 sctx->send_root->root_item.uuid);
2579
2580 TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID,
2581 btrfs_root_ctransid(&sctx->send_root->root_item));
2582 if (parent_root) {
2583 if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid))
2584 TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
2585 parent_root->root_item.received_uuid);
2586 else
2587 TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
2588 parent_root->root_item.uuid);
2589 TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
2590 btrfs_root_ctransid(&sctx->parent_root->root_item));
2591 }
2592
2593 ret = send_cmd(sctx);
2594
2595 tlv_put_failure:
2596 out:
2597 btrfs_free_path(path);
2598 kfree(name);
2599 return ret;
2600 }
2601
2602 static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size)
2603 {
2604 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2605 int ret = 0;
2606 struct fs_path *p;
2607
2608 btrfs_debug(fs_info, "send_truncate %llu size=%llu", ino, size);
2609
2610 p = fs_path_alloc();
2611 if (!p)
2612 return -ENOMEM;
2613
2614 ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE);
2615 if (ret < 0)
2616 goto out;
2617
2618 ret = get_cur_path(sctx, ino, gen, p);
2619 if (ret < 0)
2620 goto out;
2621 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2622 TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size);
2623
2624 ret = send_cmd(sctx);
2625
2626 tlv_put_failure:
2627 out:
2628 fs_path_free(p);
2629 return ret;
2630 }
2631
2632 static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode)
2633 {
2634 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2635 int ret = 0;
2636 struct fs_path *p;
2637
2638 btrfs_debug(fs_info, "send_chmod %llu mode=%llu", ino, mode);
2639
2640 p = fs_path_alloc();
2641 if (!p)
2642 return -ENOMEM;
2643
2644 ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD);
2645 if (ret < 0)
2646 goto out;
2647
2648 ret = get_cur_path(sctx, ino, gen, p);
2649 if (ret < 0)
2650 goto out;
2651 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2652 TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777);
2653
2654 ret = send_cmd(sctx);
2655
2656 tlv_put_failure:
2657 out:
2658 fs_path_free(p);
2659 return ret;
2660 }
2661
2662 static int send_fileattr(struct send_ctx *sctx, u64 ino, u64 gen, u64 fileattr)
2663 {
2664 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2665 int ret = 0;
2666 struct fs_path *p;
2667
2668 if (sctx->proto < 2)
2669 return 0;
2670
2671 btrfs_debug(fs_info, "send_fileattr %llu fileattr=%llu", ino, fileattr);
2672
2673 p = fs_path_alloc();
2674 if (!p)
2675 return -ENOMEM;
2676
2677 ret = begin_cmd(sctx, BTRFS_SEND_C_FILEATTR);
2678 if (ret < 0)
2679 goto out;
2680
2681 ret = get_cur_path(sctx, ino, gen, p);
2682 if (ret < 0)
2683 goto out;
2684 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2685 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILEATTR, fileattr);
2686
2687 ret = send_cmd(sctx);
2688
2689 tlv_put_failure:
2690 out:
2691 fs_path_free(p);
2692 return ret;
2693 }
2694
2695 static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid)
2696 {
2697 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2698 int ret = 0;
2699 struct fs_path *p;
2700
2701 btrfs_debug(fs_info, "send_chown %llu uid=%llu, gid=%llu",
2702 ino, uid, gid);
2703
2704 p = fs_path_alloc();
2705 if (!p)
2706 return -ENOMEM;
2707
2708 ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN);
2709 if (ret < 0)
2710 goto out;
2711
2712 ret = get_cur_path(sctx, ino, gen, p);
2713 if (ret < 0)
2714 goto out;
2715 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2716 TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid);
2717 TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid);
2718
2719 ret = send_cmd(sctx);
2720
2721 tlv_put_failure:
2722 out:
2723 fs_path_free(p);
2724 return ret;
2725 }
2726
2727 static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen)
2728 {
2729 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2730 int ret = 0;
2731 struct fs_path *p = NULL;
2732 struct btrfs_inode_item *ii;
2733 struct btrfs_path *path = NULL;
2734 struct extent_buffer *eb;
2735 struct btrfs_key key;
2736 int slot;
2737
2738 btrfs_debug(fs_info, "send_utimes %llu", ino);
2739
2740 p = fs_path_alloc();
2741 if (!p)
2742 return -ENOMEM;
2743
2744 path = alloc_path_for_send();
2745 if (!path) {
2746 ret = -ENOMEM;
2747 goto out;
2748 }
2749
2750 key.objectid = ino;
2751 key.type = BTRFS_INODE_ITEM_KEY;
2752 key.offset = 0;
2753 ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
2754 if (ret > 0)
2755 ret = -ENOENT;
2756 if (ret < 0)
2757 goto out;
2758
2759 eb = path->nodes[0];
2760 slot = path->slots[0];
2761 ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);
2762
2763 ret = begin_cmd(sctx, BTRFS_SEND_C_UTIMES);
2764 if (ret < 0)
2765 goto out;
2766
2767 ret = get_cur_path(sctx, ino, gen, p);
2768 if (ret < 0)
2769 goto out;
2770 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2771 TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, eb, &ii->atime);
2772 TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb, &ii->mtime);
2773 TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb, &ii->ctime);
2774 if (sctx->proto >= 2)
2775 TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_OTIME, eb, &ii->otime);
2776
2777 ret = send_cmd(sctx);
2778
2779 tlv_put_failure:
2780 out:
2781 fs_path_free(p);
2782 btrfs_free_path(path);
2783 return ret;
2784 }
2785
2786 /*
2787 * If the cache is full, we can't remove entries from it and do a call to
2788 * send_utimes() for each respective inode, because we might be finishing
2789 * processing an inode that is a directory and it just got renamed, and existing
2790 * entries in the cache may refer to inodes that have the directory in their
2791 * full path - in which case we would generate outdated paths (pre-rename)
2792 * for the inodes that the cache entries point to. Instead of prunning the
2793 * cache when inserting, do it after we finish processing each inode at
2794 * finish_inode_if_needed().
2795 */
2796 static int cache_dir_utimes(struct send_ctx *sctx, u64 dir, u64 gen)
2797 {
2798 struct btrfs_lru_cache_entry *entry;
2799 int ret;
2800
2801 entry = btrfs_lru_cache_lookup(&sctx->dir_utimes_cache, dir, gen);
2802 if (entry != NULL)
2803 return 0;
2804
2805 /* Caching is optional, don't fail if we can't allocate memory. */
2806 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2807 if (!entry)
2808 return send_utimes(sctx, dir, gen);
2809
2810 entry->key = dir;
2811 entry->gen = gen;
2812
2813 ret = btrfs_lru_cache_store(&sctx->dir_utimes_cache, entry, GFP_KERNEL);
2814 ASSERT(ret != -EEXIST);
2815 if (ret) {
2816 kfree(entry);
2817 return send_utimes(sctx, dir, gen);
2818 }
2819
2820 return 0;
2821 }
2822
2823 static int trim_dir_utimes_cache(struct send_ctx *sctx)
2824 {
2825 while (sctx->dir_utimes_cache.size > SEND_MAX_DIR_UTIMES_CACHE_SIZE) {
2826 struct btrfs_lru_cache_entry *lru;
2827 int ret;
2828
2829 lru = btrfs_lru_cache_lru_entry(&sctx->dir_utimes_cache);
2830 ASSERT(lru != NULL);
2831
2832 ret = send_utimes(sctx, lru->key, lru->gen);
2833 if (ret)
2834 return ret;
2835
2836 btrfs_lru_cache_remove(&sctx->dir_utimes_cache, lru);
2837 }
2838
2839 return 0;
2840 }
2841
2842 /*
2843 * Sends a BTRFS_SEND_C_MKXXX or SYMLINK command to user space. We don't have
2844 * a valid path yet because we did not process the refs yet. So, the inode
2845 * is created as orphan.
2846 */
2847 static int send_create_inode(struct send_ctx *sctx, u64 ino)
2848 {
2849 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2850 int ret = 0;
2851 struct fs_path *p;
2852 int cmd;
2853 struct btrfs_inode_info info;
2854 u64 gen;
2855 u64 mode;
2856 u64 rdev;
2857
2858 btrfs_debug(fs_info, "send_create_inode %llu", ino);
2859
2860 p = fs_path_alloc();
2861 if (!p)
2862 return -ENOMEM;
2863
2864 if (ino != sctx->cur_ino) {
2865 ret = get_inode_info(sctx->send_root, ino, &info);
2866 if (ret < 0)
2867 goto out;
2868 gen = info.gen;
2869 mode = info.mode;
2870 rdev = info.rdev;
2871 } else {
2872 gen = sctx->cur_inode_gen;
2873 mode = sctx->cur_inode_mode;
2874 rdev = sctx->cur_inode_rdev;
2875 }
2876
2877 if (S_ISREG(mode)) {
2878 cmd = BTRFS_SEND_C_MKFILE;
2879 } else if (S_ISDIR(mode)) {
2880 cmd = BTRFS_SEND_C_MKDIR;
2881 } else if (S_ISLNK(mode)) {
2882 cmd = BTRFS_SEND_C_SYMLINK;
2883 } else if (S_ISCHR(mode) || S_ISBLK(mode)) {
2884 cmd = BTRFS_SEND_C_MKNOD;
2885 } else if (S_ISFIFO(mode)) {
2886 cmd = BTRFS_SEND_C_MKFIFO;
2887 } else if (S_ISSOCK(mode)) {
2888 cmd = BTRFS_SEND_C_MKSOCK;
2889 } else {
2890 btrfs_warn(sctx->send_root->fs_info, "unexpected inode type %o",
2891 (int)(mode & S_IFMT));
2892 ret = -EOPNOTSUPP;
2893 goto out;
2894 }
2895
2896 ret = begin_cmd(sctx, cmd);
2897 if (ret < 0)
2898 goto out;
2899
2900 ret = gen_unique_name(sctx, ino, gen, p);
2901 if (ret < 0)
2902 goto out;
2903
2904 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2905 TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino);
2906
2907 if (S_ISLNK(mode)) {
2908 fs_path_reset(p);
2909 ret = read_symlink(sctx->send_root, ino, p);
2910 if (ret < 0)
2911 goto out;
2912 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p);
2913 } else if (S_ISCHR(mode) || S_ISBLK(mode) ||
2914 S_ISFIFO(mode) || S_ISSOCK(mode)) {
2915 TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, new_encode_dev(rdev));
2916 TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode);
2917 }
2918
2919 ret = send_cmd(sctx);
2920 if (ret < 0)
2921 goto out;
2922
2923
2924 tlv_put_failure:
2925 out:
2926 fs_path_free(p);
2927 return ret;
2928 }
2929
2930 static void cache_dir_created(struct send_ctx *sctx, u64 dir)
2931 {
2932 struct btrfs_lru_cache_entry *entry;
2933 int ret;
2934
2935 /* Caching is optional, ignore any failures. */
2936 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2937 if (!entry)
2938 return;
2939
2940 entry->key = dir;
2941 entry->gen = 0;
2942 ret = btrfs_lru_cache_store(&sctx->dir_created_cache, entry, GFP_KERNEL);
2943 if (ret < 0)
2944 kfree(entry);
2945 }
2946
2947 /*
2948 * We need some special handling for inodes that get processed before the parent
2949 * directory got created. See process_recorded_refs for details.
2950 * This function does the check if we already created the dir out of order.
2951 */
2952 static int did_create_dir(struct send_ctx *sctx, u64 dir)
2953 {
2954 int ret = 0;
2955 int iter_ret = 0;
2956 struct btrfs_path *path = NULL;
2957 struct btrfs_key key;
2958 struct btrfs_key found_key;
2959 struct btrfs_key di_key;
2960 struct btrfs_dir_item *di;
2961
2962 if (btrfs_lru_cache_lookup(&sctx->dir_created_cache, dir, 0))
2963 return 1;
2964
2965 path = alloc_path_for_send();
2966 if (!path)
2967 return -ENOMEM;
2968
2969 key.objectid = dir;
2970 key.type = BTRFS_DIR_INDEX_KEY;
2971 key.offset = 0;
2972
2973 btrfs_for_each_slot(sctx->send_root, &key, &found_key, path, iter_ret) {
2974 struct extent_buffer *eb = path->nodes[0];
2975
2976 if (found_key.objectid != key.objectid ||
2977 found_key.type != key.type) {
2978 ret = 0;
2979 break;
2980 }
2981
2982 di = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dir_item);
2983 btrfs_dir_item_key_to_cpu(eb, di, &di_key);
2984
2985 if (di_key.type != BTRFS_ROOT_ITEM_KEY &&
2986 di_key.objectid < sctx->send_progress) {
2987 ret = 1;
2988 cache_dir_created(sctx, dir);
2989 break;
2990 }
2991 }
2992 /* Catch error found during iteration */
2993 if (iter_ret < 0)
2994 ret = iter_ret;
2995
2996 btrfs_free_path(path);
2997 return ret;
2998 }
2999
3000 /*
3001 * Only creates the inode if it is:
3002 * 1. Not a directory
3003 * 2. Or a directory which was not created already due to out of order
3004 * directories. See did_create_dir and process_recorded_refs for details.
3005 */
3006 static int send_create_inode_if_needed(struct send_ctx *sctx)
3007 {
3008 int ret;
3009
3010 if (S_ISDIR(sctx->cur_inode_mode)) {
3011 ret = did_create_dir(sctx, sctx->cur_ino);
3012 if (ret < 0)
3013 return ret;
3014 else if (ret > 0)
3015 return 0;
3016 }
3017
3018 ret = send_create_inode(sctx, sctx->cur_ino);
3019
3020 if (ret == 0 && S_ISDIR(sctx->cur_inode_mode))
3021 cache_dir_created(sctx, sctx->cur_ino);
3022
3023 return ret;
3024 }
3025
3026 struct recorded_ref {
3027 struct list_head list;
3028 char *name;
3029 struct fs_path *full_path;
3030 u64 dir;
3031 u64 dir_gen;
3032 int name_len;
3033 struct rb_node node;
3034 struct rb_root *root;
3035 };
3036
3037 static struct recorded_ref *recorded_ref_alloc(void)
3038 {
3039 struct recorded_ref *ref;
3040
3041 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
3042 if (!ref)
3043 return NULL;
3044 RB_CLEAR_NODE(&ref->node);
3045 INIT_LIST_HEAD(&ref->list);
3046 return ref;
3047 }
3048
3049 static void recorded_ref_free(struct recorded_ref *ref)
3050 {
3051 if (!ref)
3052 return;
3053 if (!RB_EMPTY_NODE(&ref->node))
3054 rb_erase(&ref->node, ref->root);
3055 list_del(&ref->list);
3056 fs_path_free(ref->full_path);
3057 kfree(ref);
3058 }
3059
3060 static void set_ref_path(struct recorded_ref *ref, struct fs_path *path)
3061 {
3062 ref->full_path = path;
3063 ref->name = (char *)kbasename(ref->full_path->start);
3064 ref->name_len = ref->full_path->end - ref->name;
3065 }
3066
3067 static int dup_ref(struct recorded_ref *ref, struct list_head *list)
3068 {
3069 struct recorded_ref *new;
3070
3071 new = recorded_ref_alloc();
3072 if (!new)
3073 return -ENOMEM;
3074
3075 new->dir = ref->dir;
3076 new->dir_gen = ref->dir_gen;
3077 list_add_tail(&new->list, list);
3078 return 0;
3079 }
3080
3081 static void __free_recorded_refs(struct list_head *head)
3082 {
3083 struct recorded_ref *cur;
3084
3085 while (!list_empty(head)) {
3086 cur = list_entry(head->next, struct recorded_ref, list);
3087 recorded_ref_free(cur);
3088 }
3089 }
3090
3091 static void free_recorded_refs(struct send_ctx *sctx)
3092 {
3093 __free_recorded_refs(&sctx->new_refs);
3094 __free_recorded_refs(&sctx->deleted_refs);
3095 }
3096
3097 /*
3098 * Renames/moves a file/dir to its orphan name. Used when the first
3099 * ref of an unprocessed inode gets overwritten and for all non empty
3100 * directories.
3101 */
3102 static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen,
3103 struct fs_path *path)
3104 {
3105 int ret;
3106 struct fs_path *orphan;
3107
3108 orphan = fs_path_alloc();
3109 if (!orphan)
3110 return -ENOMEM;
3111
3112 ret = gen_unique_name(sctx, ino, gen, orphan);
3113 if (ret < 0)
3114 goto out;
3115
3116 ret = send_rename(sctx, path, orphan);
3117
3118 out:
3119 fs_path_free(orphan);
3120 return ret;
3121 }
3122
3123 static struct orphan_dir_info *add_orphan_dir_info(struct send_ctx *sctx,
3124 u64 dir_ino, u64 dir_gen)
3125 {
3126 struct rb_node **p = &sctx->orphan_dirs.rb_node;
3127 struct rb_node *parent = NULL;
3128 struct orphan_dir_info *entry, *odi;
3129
3130 while (*p) {
3131 parent = *p;
3132 entry = rb_entry(parent, struct orphan_dir_info, node);
3133 if (dir_ino < entry->ino)
3134 p = &(*p)->rb_left;
3135 else if (dir_ino > entry->ino)
3136 p = &(*p)->rb_right;
3137 else if (dir_gen < entry->gen)
3138 p = &(*p)->rb_left;
3139 else if (dir_gen > entry->gen)
3140 p = &(*p)->rb_right;
3141 else
3142 return entry;
3143 }
3144
3145 odi = kmalloc(sizeof(*odi), GFP_KERNEL);
3146 if (!odi)
3147 return ERR_PTR(-ENOMEM);
3148 odi->ino = dir_ino;
3149 odi->gen = dir_gen;
3150 odi->last_dir_index_offset = 0;
3151 odi->dir_high_seq_ino = 0;
3152
3153 rb_link_node(&odi->node, parent, p);
3154 rb_insert_color(&odi->node, &sctx->orphan_dirs);
3155 return odi;
3156 }
3157
3158 static struct orphan_dir_info *get_orphan_dir_info(struct send_ctx *sctx,
3159 u64 dir_ino, u64 gen)
3160 {
3161 struct rb_node *n = sctx->orphan_dirs.rb_node;
3162 struct orphan_dir_info *entry;
3163
3164 while (n) {
3165 entry = rb_entry(n, struct orphan_dir_info, node);
3166 if (dir_ino < entry->ino)
3167 n = n->rb_left;
3168 else if (dir_ino > entry->ino)
3169 n = n->rb_right;
3170 else if (gen < entry->gen)
3171 n = n->rb_left;
3172 else if (gen > entry->gen)
3173 n = n->rb_right;
3174 else
3175 return entry;
3176 }
3177 return NULL;
3178 }
3179
3180 static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen)
3181 {
3182 struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino, gen);
3183
3184 return odi != NULL;
3185 }
3186
3187 static void free_orphan_dir_info(struct send_ctx *sctx,
3188 struct orphan_dir_info *odi)
3189 {
3190 if (!odi)
3191 return;
3192 rb_erase(&odi->node, &sctx->orphan_dirs);
3193 kfree(odi);
3194 }
3195
3196 /*
3197 * Returns 1 if a directory can be removed at this point in time.
3198 * We check this by iterating all dir items and checking if the inode behind
3199 * the dir item was already processed.
3200 */
3201 static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen)
3202 {
3203 int ret = 0;
3204 int iter_ret = 0;
3205 struct btrfs_root *root = sctx->parent_root;
3206 struct btrfs_path *path;
3207 struct btrfs_key key;
3208 struct btrfs_key found_key;
3209 struct btrfs_key loc;
3210 struct btrfs_dir_item *di;
3211 struct orphan_dir_info *odi = NULL;
3212 u64 dir_high_seq_ino = 0;
3213 u64 last_dir_index_offset = 0;
3214
3215 /*
3216 * Don't try to rmdir the top/root subvolume dir.
3217 */
3218 if (dir == BTRFS_FIRST_FREE_OBJECTID)
3219 return 0;
3220
3221 odi = get_orphan_dir_info(sctx, dir, dir_gen);
3222 if (odi && sctx->cur_ino < odi->dir_high_seq_ino)
3223 return 0;
3224
3225 path = alloc_path_for_send();
3226 if (!path)
3227 return -ENOMEM;
3228
3229 if (!odi) {
3230 /*
3231 * Find the inode number associated with the last dir index
3232 * entry. This is very likely the inode with the highest number
3233 * of all inodes that have an entry in the directory. We can
3234 * then use it to avoid future calls to can_rmdir(), when
3235 * processing inodes with a lower number, from having to search
3236 * the parent root b+tree for dir index keys.
3237 */
3238 key.objectid = dir;
3239 key.type = BTRFS_DIR_INDEX_KEY;
3240 key.offset = (u64)-1;
3241
3242 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3243 if (ret < 0) {
3244 goto out;
3245 } else if (ret > 0) {
3246 /* Can't happen, the root is never empty. */
3247 ASSERT(path->slots[0] > 0);
3248 if (WARN_ON(path->slots[0] == 0)) {
3249 ret = -EUCLEAN;
3250 goto out;
3251 }
3252 path->slots[0]--;
3253 }
3254
3255 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3256 if (key.objectid != dir || key.type != BTRFS_DIR_INDEX_KEY) {
3257 /* No index keys, dir can be removed. */
3258 ret = 1;
3259 goto out;
3260 }
3261
3262 di = btrfs_item_ptr(path->nodes[0], path->slots[0],
3263 struct btrfs_dir_item);
3264 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc);
3265 dir_high_seq_ino = loc.objectid;
3266 if (sctx->cur_ino < dir_high_seq_ino) {
3267 ret = 0;
3268 goto out;
3269 }
3270
3271 btrfs_release_path(path);
3272 }
3273
3274 key.objectid = dir;
3275 key.type = BTRFS_DIR_INDEX_KEY;
3276 key.offset = (odi ? odi->last_dir_index_offset : 0);
3277
3278 btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
3279 struct waiting_dir_move *dm;
3280
3281 if (found_key.objectid != key.objectid ||
3282 found_key.type != key.type)
3283 break;
3284
3285 di = btrfs_item_ptr(path->nodes[0], path->slots[0],
3286 struct btrfs_dir_item);
3287 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc);
3288
3289 dir_high_seq_ino = max(dir_high_seq_ino, loc.objectid);
3290 last_dir_index_offset = found_key.offset;
3291
3292 dm = get_waiting_dir_move(sctx, loc.objectid);
3293 if (dm) {
3294 dm->rmdir_ino = dir;
3295 dm->rmdir_gen = dir_gen;
3296 ret = 0;
3297 goto out;
3298 }
3299
3300 if (loc.objectid > sctx->cur_ino) {
3301 ret = 0;
3302 goto out;
3303 }
3304 }
3305 if (iter_ret < 0) {
3306 ret = iter_ret;
3307 goto out;
3308 }
3309 free_orphan_dir_info(sctx, odi);
3310
3311 ret = 1;
3312
3313 out:
3314 btrfs_free_path(path);
3315
3316 if (ret)
3317 return ret;
3318
3319 if (!odi) {
3320 odi = add_orphan_dir_info(sctx, dir, dir_gen);
3321 if (IS_ERR(odi))
3322 return PTR_ERR(odi);
3323
3324 odi->gen = dir_gen;
3325 }
3326
3327 odi->last_dir_index_offset = last_dir_index_offset;
3328 odi->dir_high_seq_ino = max(odi->dir_high_seq_ino, dir_high_seq_ino);
3329
3330 return 0;
3331 }
3332
3333 static int is_waiting_for_move(struct send_ctx *sctx, u64 ino)
3334 {
3335 struct waiting_dir_move *entry = get_waiting_dir_move(sctx, ino);
3336
3337 return entry != NULL;
3338 }
3339
3340 static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino, bool orphanized)
3341 {
3342 struct rb_node **p = &sctx->waiting_dir_moves.rb_node;
3343 struct rb_node *parent = NULL;
3344 struct waiting_dir_move *entry, *dm;
3345
3346 dm = kmalloc(sizeof(*dm), GFP_KERNEL);
3347 if (!dm)
3348 return -ENOMEM;
3349 dm->ino = ino;
3350 dm->rmdir_ino = 0;
3351 dm->rmdir_gen = 0;
3352 dm->orphanized = orphanized;
3353
3354 while (*p) {
3355 parent = *p;
3356 entry = rb_entry(parent, struct waiting_dir_move, node);
3357 if (ino < entry->ino) {
3358 p = &(*p)->rb_left;
3359 } else if (ino > entry->ino) {
3360 p = &(*p)->rb_right;
3361 } else {
3362 kfree(dm);
3363 return -EEXIST;
3364 }
3365 }
3366
3367 rb_link_node(&dm->node, parent, p);
3368 rb_insert_color(&dm->node, &sctx->waiting_dir_moves);
3369 return 0;
3370 }
3371
3372 static struct waiting_dir_move *
3373 get_waiting_dir_move(struct send_ctx *sctx, u64 ino)
3374 {
3375 struct rb_node *n = sctx->waiting_dir_moves.rb_node;
3376 struct waiting_dir_move *entry;
3377
3378 while (n) {
3379 entry = rb_entry(n, struct waiting_dir_move, node);
3380 if (ino < entry->ino)
3381 n = n->rb_left;
3382 else if (ino > entry->ino)
3383 n = n->rb_right;
3384 else
3385 return entry;
3386 }
3387 return NULL;
3388 }
3389
3390 static void free_waiting_dir_move(struct send_ctx *sctx,
3391 struct waiting_dir_move *dm)
3392 {
3393 if (!dm)
3394 return;
3395 rb_erase(&dm->node, &sctx->waiting_dir_moves);
3396 kfree(dm);
3397 }
3398
3399 static int add_pending_dir_move(struct send_ctx *sctx,
3400 u64 ino,
3401 u64 ino_gen,
3402 u64 parent_ino,
3403 struct list_head *new_refs,
3404 struct list_head *deleted_refs,
3405 const bool is_orphan)
3406 {
3407 struct rb_node **p = &sctx->pending_dir_moves.rb_node;
3408 struct rb_node *parent = NULL;
3409 struct pending_dir_move *entry = NULL, *pm;
3410 struct recorded_ref *cur;
3411 int exists = 0;
3412 int ret;
3413
3414 pm = kmalloc(sizeof(*pm), GFP_KERNEL);
3415 if (!pm)
3416 return -ENOMEM;
3417 pm->parent_ino = parent_ino;
3418 pm->ino = ino;
3419 pm->gen = ino_gen;
3420 INIT_LIST_HEAD(&pm->list);
3421 INIT_LIST_HEAD(&pm->update_refs);
3422 RB_CLEAR_NODE(&pm->node);
3423
3424 while (*p) {
3425 parent = *p;
3426 entry = rb_entry(parent, struct pending_dir_move, node);
3427 if (parent_ino < entry->parent_ino) {
3428 p = &(*p)->rb_left;
3429 } else if (parent_ino > entry->parent_ino) {
3430 p = &(*p)->rb_right;
3431 } else {
3432 exists = 1;
3433 break;
3434 }
3435 }
3436
3437 list_for_each_entry(cur, deleted_refs, list) {
3438 ret = dup_ref(cur, &pm->update_refs);
3439 if (ret < 0)
3440 goto out;
3441 }
3442 list_for_each_entry(cur, new_refs, list) {
3443 ret = dup_ref(cur, &pm->update_refs);
3444 if (ret < 0)
3445 goto out;
3446 }
3447
3448 ret = add_waiting_dir_move(sctx, pm->ino, is_orphan);
3449 if (ret)
3450 goto out;
3451
3452 if (exists) {
3453 list_add_tail(&pm->list, &entry->list);
3454 } else {
3455 rb_link_node(&pm->node, parent, p);
3456 rb_insert_color(&pm->node, &sctx->pending_dir_moves);
3457 }
3458 ret = 0;
3459 out:
3460 if (ret) {
3461 __free_recorded_refs(&pm->update_refs);
3462 kfree(pm);
3463 }
3464 return ret;
3465 }
3466
3467 static struct pending_dir_move *get_pending_dir_moves(struct send_ctx *sctx,
3468 u64 parent_ino)
3469 {
3470 struct rb_node *n = sctx->pending_dir_moves.rb_node;
3471 struct pending_dir_move *entry;
3472
3473 while (n) {
3474 entry = rb_entry(n, struct pending_dir_move, node);
3475 if (parent_ino < entry->parent_ino)
3476 n = n->rb_left;
3477 else if (parent_ino > entry->parent_ino)
3478 n = n->rb_right;
3479 else
3480 return entry;
3481 }
3482 return NULL;
3483 }
3484
3485 static int path_loop(struct send_ctx *sctx, struct fs_path *name,
3486 u64 ino, u64 gen, u64 *ancestor_ino)
3487 {
3488 int ret = 0;
3489 u64 parent_inode = 0;
3490 u64 parent_gen = 0;
3491 u64 start_ino = ino;
3492
3493 *ancestor_ino = 0;
3494 while (ino != BTRFS_FIRST_FREE_OBJECTID) {
3495 fs_path_reset(name);
3496
3497 if (is_waiting_for_rm(sctx, ino, gen))
3498 break;
3499 if (is_waiting_for_move(sctx, ino)) {
3500 if (*ancestor_ino == 0)
3501 *ancestor_ino = ino;
3502 ret = get_first_ref(sctx->parent_root, ino,
3503 &parent_inode, &parent_gen, name);
3504 } else {
3505 ret = __get_cur_name_and_parent(sctx, ino, gen,
3506 &parent_inode,
3507 &parent_gen, name);
3508 if (ret > 0) {
3509 ret = 0;
3510 break;
3511 }
3512 }
3513 if (ret < 0)
3514 break;
3515 if (parent_inode == start_ino) {
3516 ret = 1;
3517 if (*ancestor_ino == 0)
3518 *ancestor_ino = ino;
3519 break;
3520 }
3521 ino = parent_inode;
3522 gen = parent_gen;
3523 }
3524 return ret;
3525 }
3526
3527 static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm)
3528 {
3529 struct fs_path *from_path = NULL;
3530 struct fs_path *to_path = NULL;
3531 struct fs_path *name = NULL;
3532 u64 orig_progress = sctx->send_progress;
3533 struct recorded_ref *cur;
3534 u64 parent_ino, parent_gen;
3535 struct waiting_dir_move *dm = NULL;
3536 u64 rmdir_ino = 0;
3537 u64 rmdir_gen;
3538 u64 ancestor;
3539 bool is_orphan;
3540 int ret;
3541
3542 name = fs_path_alloc();
3543 from_path = fs_path_alloc();
3544 if (!name || !from_path) {
3545 ret = -ENOMEM;
3546 goto out;
3547 }
3548
3549 dm = get_waiting_dir_move(sctx, pm->ino);
3550 ASSERT(dm);
3551 rmdir_ino = dm->rmdir_ino;
3552 rmdir_gen = dm->rmdir_gen;
3553 is_orphan = dm->orphanized;
3554 free_waiting_dir_move(sctx, dm);
3555
3556 if (is_orphan) {
3557 ret = gen_unique_name(sctx, pm->ino,
3558 pm->gen, from_path);
3559 } else {
3560 ret = get_first_ref(sctx->parent_root, pm->ino,
3561 &parent_ino, &parent_gen, name);
3562 if (ret < 0)
3563 goto out;
3564 ret = get_cur_path(sctx, parent_ino, parent_gen,
3565 from_path);
3566 if (ret < 0)
3567 goto out;
3568 ret = fs_path_add_path(from_path, name);
3569 }
3570 if (ret < 0)
3571 goto out;
3572
3573 sctx->send_progress = sctx->cur_ino + 1;
3574 ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor);
3575 if (ret < 0)
3576 goto out;
3577 if (ret) {
3578 LIST_HEAD(deleted_refs);
3579 ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID);
3580 ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor,
3581 &pm->update_refs, &deleted_refs,
3582 is_orphan);
3583 if (ret < 0)
3584 goto out;
3585 if (rmdir_ino) {
3586 dm = get_waiting_dir_move(sctx, pm->ino);
3587 ASSERT(dm);
3588 dm->rmdir_ino = rmdir_ino;
3589 dm->rmdir_gen = rmdir_gen;
3590 }
3591 goto out;
3592 }
3593 fs_path_reset(name);
3594 to_path = name;
3595 name = NULL;
3596 ret = get_cur_path(sctx, pm->ino, pm->gen, to_path);
3597 if (ret < 0)
3598 goto out;
3599
3600 ret = send_rename(sctx, from_path, to_path);
3601 if (ret < 0)
3602 goto out;
3603
3604 if (rmdir_ino) {
3605 struct orphan_dir_info *odi;
3606 u64 gen;
3607
3608 odi = get_orphan_dir_info(sctx, rmdir_ino, rmdir_gen);
3609 if (!odi) {
3610 /* already deleted */
3611 goto finish;
3612 }
3613 gen = odi->gen;
3614
3615 ret = can_rmdir(sctx, rmdir_ino, gen);
3616 if (ret < 0)
3617 goto out;
3618 if (!ret)
3619 goto finish;
3620
3621 name = fs_path_alloc();
3622 if (!name) {
3623 ret = -ENOMEM;
3624 goto out;
3625 }
3626 ret = get_cur_path(sctx, rmdir_ino, gen, name);
3627 if (ret < 0)
3628 goto out;
3629 ret = send_rmdir(sctx, name);
3630 if (ret < 0)
3631 goto out;
3632 }
3633
3634 finish:
3635 ret = cache_dir_utimes(sctx, pm->ino, pm->gen);
3636 if (ret < 0)
3637 goto out;
3638
3639 /*
3640 * After rename/move, need to update the utimes of both new parent(s)
3641 * and old parent(s).
3642 */
3643 list_for_each_entry(cur, &pm->update_refs, list) {
3644 /*
3645 * The parent inode might have been deleted in the send snapshot
3646 */
3647 ret = get_inode_info(sctx->send_root, cur->dir, NULL);
3648 if (ret == -ENOENT) {
3649 ret = 0;
3650 continue;
3651 }
3652 if (ret < 0)
3653 goto out;
3654
3655 ret = cache_dir_utimes(sctx, cur->dir, cur->dir_gen);
3656 if (ret < 0)
3657 goto out;
3658 }
3659
3660 out:
3661 fs_path_free(name);
3662 fs_path_free(from_path);
3663 fs_path_free(to_path);
3664 sctx->send_progress = orig_progress;
3665
3666 return ret;
3667 }
3668
3669 static void free_pending_move(struct send_ctx *sctx, struct pending_dir_move *m)
3670 {
3671 if (!list_empty(&m->list))
3672 list_del(&m->list);
3673 if (!RB_EMPTY_NODE(&m->node))
3674 rb_erase(&m->node, &sctx->pending_dir_moves);
3675 __free_recorded_refs(&m->update_refs);
3676 kfree(m);
3677 }
3678
3679 static void tail_append_pending_moves(struct send_ctx *sctx,
3680 struct pending_dir_move *moves,
3681 struct list_head *stack)
3682 {
3683 if (list_empty(&moves->list)) {
3684 list_add_tail(&moves->list, stack);
3685 } else {
3686 LIST_HEAD(list);
3687 list_splice_init(&moves->list, &list);
3688 list_add_tail(&moves->list, stack);
3689 list_splice_tail(&list, stack);
3690 }
3691 if (!RB_EMPTY_NODE(&moves->node)) {
3692 rb_erase(&moves->node, &sctx->pending_dir_moves);
3693 RB_CLEAR_NODE(&moves->node);
3694 }
3695 }
3696
3697 static int apply_children_dir_moves(struct send_ctx *sctx)
3698 {
3699 struct pending_dir_move *pm;
3700 LIST_HEAD(stack);
3701 u64 parent_ino = sctx->cur_ino;
3702 int ret = 0;
3703
3704 pm = get_pending_dir_moves(sctx, parent_ino);
3705 if (!pm)
3706 return 0;
3707
3708 tail_append_pending_moves(sctx, pm, &stack);
3709
3710 while (!list_empty(&stack)) {
3711 pm = list_first_entry(&stack, struct pending_dir_move, list);
3712 parent_ino = pm->ino;
3713 ret = apply_dir_move(sctx, pm);
3714 free_pending_move(sctx, pm);
3715 if (ret)
3716 goto out;
3717 pm = get_pending_dir_moves(sctx, parent_ino);
3718 if (pm)
3719 tail_append_pending_moves(sctx, pm, &stack);
3720 }
3721 return 0;
3722
3723 out:
3724 while (!list_empty(&stack)) {
3725 pm = list_first_entry(&stack, struct pending_dir_move, list);
3726 free_pending_move(sctx, pm);
3727 }
3728 return ret;
3729 }
3730
3731 /*
3732 * We might need to delay a directory rename even when no ancestor directory
3733 * (in the send root) with a higher inode number than ours (sctx->cur_ino) was
3734 * renamed. This happens when we rename a directory to the old name (the name
3735 * in the parent root) of some other unrelated directory that got its rename
3736 * delayed due to some ancestor with higher number that got renamed.
3737 *
3738 * Example:
3739 *
3740 * Parent snapshot:
3741 * . (ino 256)
3742 * |---- a/ (ino 257)
3743 * | |---- file (ino 260)
3744 * |
3745 * |---- b/ (ino 258)
3746 * |---- c/ (ino 259)
3747 *
3748 * Send snapshot:
3749 * . (ino 256)
3750 * |---- a/ (ino 258)
3751 * |---- x/ (ino 259)
3752 * |---- y/ (ino 257)
3753 * |----- file (ino 260)
3754 *
3755 * Here we can not rename 258 from 'b' to 'a' without the rename of inode 257
3756 * from 'a' to 'x/y' happening first, which in turn depends on the rename of
3757 * inode 259 from 'c' to 'x'. So the order of rename commands the send stream
3758 * must issue is:
3759 *
3760 * 1 - rename 259 from 'c' to 'x'
3761 * 2 - rename 257 from 'a' to 'x/y'
3762 * 3 - rename 258 from 'b' to 'a'
3763 *
3764 * Returns 1 if the rename of sctx->cur_ino needs to be delayed, 0 if it can
3765 * be done right away and < 0 on error.
3766 */
3767 static int wait_for_dest_dir_move(struct send_ctx *sctx,
3768 struct recorded_ref *parent_ref,
3769 const bool is_orphan)
3770 {
3771 struct btrfs_fs_info *fs_info = sctx->parent_root->fs_info;
3772 struct btrfs_path *path;
3773 struct btrfs_key key;
3774 struct btrfs_key di_key;
3775 struct btrfs_dir_item *di;
3776 u64 left_gen;
3777 u64 right_gen;
3778 int ret = 0;
3779 struct waiting_dir_move *wdm;
3780
3781 if (RB_EMPTY_ROOT(&sctx->waiting_dir_moves))
3782 return 0;
3783
3784 path = alloc_path_for_send();
3785 if (!path)
3786 return -ENOMEM;
3787
3788 key.objectid = parent_ref->dir;
3789 key.type = BTRFS_DIR_ITEM_KEY;
3790 key.offset = btrfs_name_hash(parent_ref->name, parent_ref->name_len);
3791
3792 ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0);
3793 if (ret < 0) {
3794 goto out;
3795 } else if (ret > 0) {
3796 ret = 0;
3797 goto out;
3798 }
3799
3800 di = btrfs_match_dir_item_name(fs_info, path, parent_ref->name,
3801 parent_ref->name_len);
3802 if (!di) {
3803 ret = 0;
3804 goto out;
3805 }
3806 /*
3807 * di_key.objectid has the number of the inode that has a dentry in the
3808 * parent directory with the same name that sctx->cur_ino is being
3809 * renamed to. We need to check if that inode is in the send root as
3810 * well and if it is currently marked as an inode with a pending rename,
3811 * if it is, we need to delay the rename of sctx->cur_ino as well, so
3812 * that it happens after that other inode is renamed.
3813 */
3814 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &di_key);
3815 if (di_key.type != BTRFS_INODE_ITEM_KEY) {
3816 ret = 0;
3817 goto out;
3818 }
3819
3820 ret = get_inode_gen(sctx->parent_root, di_key.objectid, &left_gen);
3821 if (ret < 0)
3822 goto out;
3823 ret = get_inode_gen(sctx->send_root, di_key.objectid, &right_gen);
3824 if (ret < 0) {
3825 if (ret == -ENOENT)
3826 ret = 0;
3827 goto out;
3828 }
3829
3830 /* Different inode, no need to delay the rename of sctx->cur_ino */
3831 if (right_gen != left_gen) {
3832 ret = 0;
3833 goto out;
3834 }
3835
3836 wdm = get_waiting_dir_move(sctx, di_key.objectid);
3837 if (wdm && !wdm->orphanized) {
3838 ret = add_pending_dir_move(sctx,
3839 sctx->cur_ino,
3840 sctx->cur_inode_gen,
3841 di_key.objectid,
3842 &sctx->new_refs,
3843 &sctx->deleted_refs,
3844 is_orphan);
3845 if (!ret)
3846 ret = 1;
3847 }
3848 out:
3849 btrfs_free_path(path);
3850 return ret;
3851 }
3852
3853 /*
3854 * Check if inode ino2, or any of its ancestors, is inode ino1.
3855 * Return 1 if true, 0 if false and < 0 on error.
3856 */
3857 static int check_ino_in_path(struct btrfs_root *root,
3858 const u64 ino1,
3859 const u64 ino1_gen,
3860 const u64 ino2,
3861 const u64 ino2_gen,
3862 struct fs_path *fs_path)
3863 {
3864 u64 ino = ino2;
3865
3866 if (ino1 == ino2)
3867 return ino1_gen == ino2_gen;
3868
3869 while (ino > BTRFS_FIRST_FREE_OBJECTID) {
3870 u64 parent;
3871 u64 parent_gen;
3872 int ret;
3873
3874 fs_path_reset(fs_path);
3875 ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path);
3876 if (ret < 0)
3877 return ret;
3878 if (parent == ino1)
3879 return parent_gen == ino1_gen;
3880 ino = parent;
3881 }
3882 return 0;
3883 }
3884
3885 /*
3886 * Check if inode ino1 is an ancestor of inode ino2 in the given root for any
3887 * possible path (in case ino2 is not a directory and has multiple hard links).
3888 * Return 1 if true, 0 if false and < 0 on error.
3889 */
3890 static int is_ancestor(struct btrfs_root *root,
3891 const u64 ino1,
3892 const u64 ino1_gen,
3893 const u64 ino2,
3894 struct fs_path *fs_path)
3895 {
3896 bool free_fs_path = false;
3897 int ret = 0;
3898 int iter_ret = 0;
3899 struct btrfs_path *path = NULL;
3900 struct btrfs_key key;
3901
3902 if (!fs_path) {
3903 fs_path = fs_path_alloc();
3904 if (!fs_path)
3905 return -ENOMEM;
3906 free_fs_path = true;
3907 }
3908
3909 path = alloc_path_for_send();
3910 if (!path) {
3911 ret = -ENOMEM;
3912 goto out;
3913 }
3914
3915 key.objectid = ino2;
3916 key.type = BTRFS_INODE_REF_KEY;
3917 key.offset = 0;
3918
3919 btrfs_for_each_slot(root, &key, &key, path, iter_ret) {
3920 struct extent_buffer *leaf = path->nodes[0];
3921 int slot = path->slots[0];
3922 u32 cur_offset = 0;
3923 u32 item_size;
3924
3925 if (key.objectid != ino2)
3926 break;
3927 if (key.type != BTRFS_INODE_REF_KEY &&
3928 key.type != BTRFS_INODE_EXTREF_KEY)
3929 break;
3930
3931 item_size = btrfs_item_size(leaf, slot);
3932 while (cur_offset < item_size) {
3933 u64 parent;
3934 u64 parent_gen;
3935
3936 if (key.type == BTRFS_INODE_EXTREF_KEY) {
3937 unsigned long ptr;
3938 struct btrfs_inode_extref *extref;
3939
3940 ptr = btrfs_item_ptr_offset(leaf, slot);
3941 extref = (struct btrfs_inode_extref *)
3942 (ptr + cur_offset);
3943 parent = btrfs_inode_extref_parent(leaf,
3944 extref);
3945 cur_offset += sizeof(*extref);
3946 cur_offset += btrfs_inode_extref_name_len(leaf,
3947 extref);
3948 } else {
3949 parent = key.offset;
3950 cur_offset = item_size;
3951 }
3952
3953 ret = get_inode_gen(root, parent, &parent_gen);
3954 if (ret < 0)
3955 goto out;
3956 ret = check_ino_in_path(root, ino1, ino1_gen,
3957 parent, parent_gen, fs_path);
3958 if (ret)
3959 goto out;
3960 }
3961 }
3962 ret = 0;
3963 if (iter_ret < 0)
3964 ret = iter_ret;
3965
3966 out:
3967 btrfs_free_path(path);
3968 if (free_fs_path)
3969 fs_path_free(fs_path);
3970 return ret;
3971 }
3972
3973 static int wait_for_parent_move(struct send_ctx *sctx,
3974 struct recorded_ref *parent_ref,
3975 const bool is_orphan)
3976 {
3977 int ret = 0;
3978 u64 ino = parent_ref->dir;
3979 u64 ino_gen = parent_ref->dir_gen;
3980 u64 parent_ino_before, parent_ino_after;
3981 struct fs_path *path_before = NULL;
3982 struct fs_path *path_after = NULL;
3983 int len1, len2;
3984
3985 path_after = fs_path_alloc();
3986 path_before = fs_path_alloc();
3987 if (!path_after || !path_before) {
3988 ret = -ENOMEM;
3989 goto out;
3990 }
3991
3992 /*
3993 * Our current directory inode may not yet be renamed/moved because some
3994 * ancestor (immediate or not) has to be renamed/moved first. So find if
3995 * such ancestor exists and make sure our own rename/move happens after
3996 * that ancestor is processed to avoid path build infinite loops (done
3997 * at get_cur_path()).
3998 */
3999 while (ino > BTRFS_FIRST_FREE_OBJECTID) {
4000 u64 parent_ino_after_gen;
4001
4002 if (is_waiting_for_move(sctx, ino)) {
4003 /*
4004 * If the current inode is an ancestor of ino in the
4005 * parent root, we need to delay the rename of the
4006 * current inode, otherwise don't delayed the rename
4007 * because we can end up with a circular dependency
4008 * of renames, resulting in some directories never
4009 * getting the respective rename operations issued in
4010 * the send stream or getting into infinite path build
4011 * loops.
4012 */
4013 ret = is_ancestor(sctx->parent_root,
4014 sctx->cur_ino, sctx->cur_inode_gen,
4015 ino, path_before);
4016 if (ret)
4017 break;
4018 }
4019
4020 fs_path_reset(path_before);
4021 fs_path_reset(path_after);
4022
4023 ret = get_first_ref(sctx->send_root, ino, &parent_ino_after,
4024 &parent_ino_after_gen, path_after);
4025 if (ret < 0)
4026 goto out;
4027 ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before,
4028 NULL, path_before);
4029 if (ret < 0 && ret != -ENOENT) {
4030 goto out;
4031 } else if (ret == -ENOENT) {
4032 ret = 0;
4033 break;
4034 }
4035
4036 len1 = fs_path_len(path_before);
4037 len2 = fs_path_len(path_after);
4038 if (ino > sctx->cur_ino &&
4039 (parent_ino_before != parent_ino_after || len1 != len2 ||
4040 memcmp(path_before->start, path_after->start, len1))) {
4041 u64 parent_ino_gen;
4042
4043 ret = get_inode_gen(sctx->parent_root, ino, &parent_ino_gen);
4044 if (ret < 0)
4045 goto out;
4046 if (ino_gen == parent_ino_gen) {
4047 ret = 1;
4048 break;
4049 }
4050 }
4051 ino = parent_ino_after;
4052 ino_gen = parent_ino_after_gen;
4053 }
4054
4055 out:
4056 fs_path_free(path_before);
4057 fs_path_free(path_after);
4058
4059 if (ret == 1) {
4060 ret = add_pending_dir_move(sctx,
4061 sctx->cur_ino,
4062 sctx->cur_inode_gen,
4063 ino,
4064 &sctx->new_refs,
4065 &sctx->deleted_refs,
4066 is_orphan);
4067 if (!ret)
4068 ret = 1;
4069 }
4070
4071 return ret;
4072 }
4073
4074 static int update_ref_path(struct send_ctx *sctx, struct recorded_ref *ref)
4075 {
4076 int ret;
4077 struct fs_path *new_path;
4078
4079 /*
4080 * Our reference's name member points to its full_path member string, so
4081 * we use here a new path.
4082 */
4083 new_path = fs_path_alloc();
4084 if (!new_path)
4085 return -ENOMEM;
4086
4087 ret = get_cur_path(sctx, ref->dir, ref->dir_gen, new_path);
4088 if (ret < 0) {
4089 fs_path_free(new_path);
4090 return ret;
4091 }
4092 ret = fs_path_add(new_path, ref->name, ref->name_len);
4093 if (ret < 0) {
4094 fs_path_free(new_path);
4095 return ret;
4096 }
4097
4098 fs_path_free(ref->full_path);
4099 set_ref_path(ref, new_path);
4100
4101 return 0;
4102 }
4103
4104 /*
4105 * When processing the new references for an inode we may orphanize an existing
4106 * directory inode because its old name conflicts with one of the new references
4107 * of the current inode. Later, when processing another new reference of our
4108 * inode, we might need to orphanize another inode, but the path we have in the
4109 * reference reflects the pre-orphanization name of the directory we previously
4110 * orphanized. For example:
4111 *
4112 * parent snapshot looks like:
4113 *
4114 * . (ino 256)
4115 * |----- f1 (ino 257)
4116 * |----- f2 (ino 258)
4117 * |----- d1/ (ino 259)
4118 * |----- d2/ (ino 260)
4119 *
4120 * send snapshot looks like:
4121 *
4122 * . (ino 256)
4123 * |----- d1 (ino 258)
4124 * |----- f2/ (ino 259)
4125 * |----- f2_link/ (ino 260)
4126 * | |----- f1 (ino 257)
4127 * |
4128 * |----- d2 (ino 258)
4129 *
4130 * When processing inode 257 we compute the name for inode 259 as "d1", and we
4131 * cache it in the name cache. Later when we start processing inode 258, when
4132 * collecting all its new references we set a full path of "d1/d2" for its new
4133 * reference with name "d2". When we start processing the new references we
4134 * start by processing the new reference with name "d1", and this results in
4135 * orphanizing inode 259, since its old reference causes a conflict. Then we
4136 * move on the next new reference, with name "d2", and we find out we must
4137 * orphanize inode 260, as its old reference conflicts with ours - but for the
4138 * orphanization we use a source path corresponding to the path we stored in the
4139 * new reference, which is "d1/d2" and not "o259-6-0/d2" - this makes the
4140 * receiver fail since the path component "d1/" no longer exists, it was renamed
4141 * to "o259-6-0/" when processing the previous new reference. So in this case we
4142 * must recompute the path in the new reference and use it for the new
4143 * orphanization operation.
4144 */
4145 static int refresh_ref_path(struct send_ctx *sctx, struct recorded_ref *ref)
4146 {
4147 char *name;
4148 int ret;
4149
4150 name = kmemdup(ref->name, ref->name_len, GFP_KERNEL);
4151 if (!name)
4152 return -ENOMEM;
4153
4154 fs_path_reset(ref->full_path);
4155 ret = get_cur_path(sctx, ref->dir, ref->dir_gen, ref->full_path);
4156 if (ret < 0)
4157 goto out;
4158
4159 ret = fs_path_add(ref->full_path, name, ref->name_len);
4160 if (ret < 0)
4161 goto out;
4162
4163 /* Update the reference's base name pointer. */
4164 set_ref_path(ref, ref->full_path);
4165 out:
4166 kfree(name);
4167 return ret;
4168 }
4169
4170 /*
4171 * This does all the move/link/unlink/rmdir magic.
4172 */
4173 static int process_recorded_refs(struct send_ctx *sctx, int *pending_move)
4174 {
4175 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
4176 int ret = 0;
4177 struct recorded_ref *cur;
4178 struct recorded_ref *cur2;
4179 LIST_HEAD(check_dirs);
4180 struct fs_path *valid_path = NULL;
4181 u64 ow_inode = 0;
4182 u64 ow_gen;
4183 u64 ow_mode;
4184 int did_overwrite = 0;
4185 int is_orphan = 0;
4186 u64 last_dir_ino_rm = 0;
4187 bool can_rename = true;
4188 bool orphanized_dir = false;
4189 bool orphanized_ancestor = false;
4190
4191 btrfs_debug(fs_info, "process_recorded_refs %llu", sctx->cur_ino);
4192
4193 /*
4194 * This should never happen as the root dir always has the same ref
4195 * which is always '..'
4196 */
4197 if (unlikely(sctx->cur_ino <= BTRFS_FIRST_FREE_OBJECTID)) {
4198 btrfs_err(fs_info,
4199 "send: unexpected inode %llu in process_recorded_refs()",
4200 sctx->cur_ino);
4201 ret = -EINVAL;
4202 goto out;
4203 }
4204
4205 valid_path = fs_path_alloc();
4206 if (!valid_path) {
4207 ret = -ENOMEM;
4208 goto out;
4209 }
4210
4211 /*
4212 * First, check if the first ref of the current inode was overwritten
4213 * before. If yes, we know that the current inode was already orphanized
4214 * and thus use the orphan name. If not, we can use get_cur_path to
4215 * get the path of the first ref as it would like while receiving at
4216 * this point in time.
4217 * New inodes are always orphan at the beginning, so force to use the
4218 * orphan name in this case.
4219 * The first ref is stored in valid_path and will be updated if it
4220 * gets moved around.
4221 */
4222 if (!sctx->cur_inode_new) {
4223 ret = did_overwrite_first_ref(sctx, sctx->cur_ino,
4224 sctx->cur_inode_gen);
4225 if (ret < 0)
4226 goto out;
4227 if (ret)
4228 did_overwrite = 1;
4229 }
4230 if (sctx->cur_inode_new || did_overwrite) {
4231 ret = gen_unique_name(sctx, sctx->cur_ino,
4232 sctx->cur_inode_gen, valid_path);
4233 if (ret < 0)
4234 goto out;
4235 is_orphan = 1;
4236 } else {
4237 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen,
4238 valid_path);
4239 if (ret < 0)
4240 goto out;
4241 }
4242
4243 /*
4244 * Before doing any rename and link operations, do a first pass on the
4245 * new references to orphanize any unprocessed inodes that may have a
4246 * reference that conflicts with one of the new references of the current
4247 * inode. This needs to happen first because a new reference may conflict
4248 * with the old reference of a parent directory, so we must make sure
4249 * that the path used for link and rename commands don't use an
4250 * orphanized name when an ancestor was not yet orphanized.
4251 *
4252 * Example:
4253 *
4254 * Parent snapshot:
4255 *
4256 * . (ino 256)
4257 * |----- testdir/ (ino 259)
4258 * | |----- a (ino 257)
4259 * |
4260 * |----- b (ino 258)
4261 *
4262 * Send snapshot:
4263 *
4264 * . (ino 256)
4265 * |----- testdir_2/ (ino 259)
4266 * | |----- a (ino 260)
4267 * |
4268 * |----- testdir (ino 257)
4269 * |----- b (ino 257)
4270 * |----- b2 (ino 258)
4271 *
4272 * Processing the new reference for inode 257 with name "b" may happen
4273 * before processing the new reference with name "testdir". If so, we
4274 * must make sure that by the time we send a link command to create the
4275 * hard link "b", inode 259 was already orphanized, since the generated
4276 * path in "valid_path" already contains the orphanized name for 259.
4277 * We are processing inode 257, so only later when processing 259 we do
4278 * the rename operation to change its temporary (orphanized) name to
4279 * "testdir_2".
4280 */
4281 list_for_each_entry(cur, &sctx->new_refs, list) {
4282 ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen, NULL, NULL);
4283 if (ret < 0)
4284 goto out;
4285 if (ret == inode_state_will_create)
4286 continue;
4287
4288 /*
4289 * Check if this new ref would overwrite the first ref of another
4290 * unprocessed inode. If yes, orphanize the overwritten inode.
4291 * If we find an overwritten ref that is not the first ref,
4292 * simply unlink it.
4293 */
4294 ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen,
4295 cur->name, cur->name_len,
4296 &ow_inode, &ow_gen, &ow_mode);
4297 if (ret < 0)
4298 goto out;
4299 if (ret) {
4300 ret = is_first_ref(sctx->parent_root,
4301 ow_inode, cur->dir, cur->name,
4302 cur->name_len);
4303 if (ret < 0)
4304 goto out;
4305 if (ret) {
4306 struct name_cache_entry *nce;
4307 struct waiting_dir_move *wdm;
4308
4309 if (orphanized_dir) {
4310 ret = refresh_ref_path(sctx, cur);
4311 if (ret < 0)
4312 goto out;
4313 }
4314
4315 ret = orphanize_inode(sctx, ow_inode, ow_gen,
4316 cur->full_path);
4317 if (ret < 0)
4318 goto out;
4319 if (S_ISDIR(ow_mode))
4320 orphanized_dir = true;
4321
4322 /*
4323 * If ow_inode has its rename operation delayed
4324 * make sure that its orphanized name is used in
4325 * the source path when performing its rename
4326 * operation.
4327 */
4328 wdm = get_waiting_dir_move(sctx, ow_inode);
4329 if (wdm)
4330 wdm->orphanized = true;
4331
4332 /*
4333 * Make sure we clear our orphanized inode's
4334 * name from the name cache. This is because the
4335 * inode ow_inode might be an ancestor of some
4336 * other inode that will be orphanized as well
4337 * later and has an inode number greater than
4338 * sctx->send_progress. We need to prevent
4339 * future name lookups from using the old name
4340 * and get instead the orphan name.
4341 */
4342 nce = name_cache_search(sctx, ow_inode, ow_gen);
4343 if (nce)
4344 btrfs_lru_cache_remove(&sctx->name_cache,
4345 &nce->entry);
4346
4347 /*
4348 * ow_inode might currently be an ancestor of
4349 * cur_ino, therefore compute valid_path (the
4350 * current path of cur_ino) again because it
4351 * might contain the pre-orphanization name of
4352 * ow_inode, which is no longer valid.
4353 */
4354 ret = is_ancestor(sctx->parent_root,
4355 ow_inode, ow_gen,
4356 sctx->cur_ino, NULL);
4357 if (ret > 0) {
4358 orphanized_ancestor = true;
4359 fs_path_reset(valid_path);
4360 ret = get_cur_path(sctx, sctx->cur_ino,
4361 sctx->cur_inode_gen,
4362 valid_path);
4363 }
4364 if (ret < 0)
4365 goto out;
4366 } else {
4367 /*
4368 * If we previously orphanized a directory that
4369 * collided with a new reference that we already
4370 * processed, recompute the current path because
4371 * that directory may be part of the path.
4372 */
4373 if (orphanized_dir) {
4374 ret = refresh_ref_path(sctx, cur);
4375 if (ret < 0)
4376 goto out;
4377 }
4378 ret = send_unlink(sctx, cur->full_path);
4379 if (ret < 0)
4380 goto out;
4381 }
4382 }
4383
4384 }
4385
4386 list_for_each_entry(cur, &sctx->new_refs, list) {
4387 /*
4388 * We may have refs where the parent directory does not exist
4389 * yet. This happens if the parent directories inum is higher
4390 * than the current inum. To handle this case, we create the
4391 * parent directory out of order. But we need to check if this
4392 * did already happen before due to other refs in the same dir.
4393 */
4394 ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen, NULL, NULL);
4395 if (ret < 0)
4396 goto out;
4397 if (ret == inode_state_will_create) {
4398 ret = 0;
4399 /*
4400 * First check if any of the current inodes refs did
4401 * already create the dir.
4402 */
4403 list_for_each_entry(cur2, &sctx->new_refs, list) {
4404 if (cur == cur2)
4405 break;
4406 if (cur2->dir == cur->dir) {
4407 ret = 1;
4408 break;
4409 }
4410 }
4411
4412 /*
4413 * If that did not happen, check if a previous inode
4414 * did already create the dir.
4415 */
4416 if (!ret)
4417 ret = did_create_dir(sctx, cur->dir);
4418 if (ret < 0)
4419 goto out;
4420 if (!ret) {
4421 ret = send_create_inode(sctx, cur->dir);
4422 if (ret < 0)
4423 goto out;
4424 cache_dir_created(sctx, cur->dir);
4425 }
4426 }
4427
4428 if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root) {
4429 ret = wait_for_dest_dir_move(sctx, cur, is_orphan);
4430 if (ret < 0)
4431 goto out;
4432 if (ret == 1) {
4433 can_rename = false;
4434 *pending_move = 1;
4435 }
4436 }
4437
4438 if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root &&
4439 can_rename) {
4440 ret = wait_for_parent_move(sctx, cur, is_orphan);
4441 if (ret < 0)
4442 goto out;
4443 if (ret == 1) {
4444 can_rename = false;
4445 *pending_move = 1;
4446 }
4447 }
4448
4449 /*
4450 * link/move the ref to the new place. If we have an orphan
4451 * inode, move it and update valid_path. If not, link or move
4452 * it depending on the inode mode.
4453 */
4454 if (is_orphan && can_rename) {
4455 ret = send_rename(sctx, valid_path, cur->full_path);
4456 if (ret < 0)
4457 goto out;
4458 is_orphan = 0;
4459 ret = fs_path_copy(valid_path, cur->full_path);
4460 if (ret < 0)
4461 goto out;
4462 } else if (can_rename) {
4463 if (S_ISDIR(sctx->cur_inode_mode)) {
4464 /*
4465 * Dirs can't be linked, so move it. For moved
4466 * dirs, we always have one new and one deleted
4467 * ref. The deleted ref is ignored later.
4468 */
4469 ret = send_rename(sctx, valid_path,
4470 cur->full_path);
4471 if (!ret)
4472 ret = fs_path_copy(valid_path,
4473 cur->full_path);
4474 if (ret < 0)
4475 goto out;
4476 } else {
4477 /*
4478 * We might have previously orphanized an inode
4479 * which is an ancestor of our current inode,
4480 * so our reference's full path, which was
4481 * computed before any such orphanizations, must
4482 * be updated.
4483 */
4484 if (orphanized_dir) {
4485 ret = update_ref_path(sctx, cur);
4486 if (ret < 0)
4487 goto out;
4488 }
4489 ret = send_link(sctx, cur->full_path,
4490 valid_path);
4491 if (ret < 0)
4492 goto out;
4493 }
4494 }
4495 ret = dup_ref(cur, &check_dirs);
4496 if (ret < 0)
4497 goto out;
4498 }
4499
4500 if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) {
4501 /*
4502 * Check if we can already rmdir the directory. If not,
4503 * orphanize it. For every dir item inside that gets deleted
4504 * later, we do this check again and rmdir it then if possible.
4505 * See the use of check_dirs for more details.
4506 */
4507 ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_inode_gen);
4508 if (ret < 0)
4509 goto out;
4510 if (ret) {
4511 ret = send_rmdir(sctx, valid_path);
4512 if (ret < 0)
4513 goto out;
4514 } else if (!is_orphan) {
4515 ret = orphanize_inode(sctx, sctx->cur_ino,
4516 sctx->cur_inode_gen, valid_path);
4517 if (ret < 0)
4518 goto out;
4519 is_orphan = 1;
4520 }
4521
4522 list_for_each_entry(cur, &sctx->deleted_refs, list) {
4523 ret = dup_ref(cur, &check_dirs);
4524 if (ret < 0)
4525 goto out;
4526 }
4527 } else if (S_ISDIR(sctx->cur_inode_mode) &&
4528 !list_empty(&sctx->deleted_refs)) {
4529 /*
4530 * We have a moved dir. Add the old parent to check_dirs
4531 */
4532 cur = list_entry(sctx->deleted_refs.next, struct recorded_ref,
4533 list);
4534 ret = dup_ref(cur, &check_dirs);
4535 if (ret < 0)
4536 goto out;
4537 } else if (!S_ISDIR(sctx->cur_inode_mode)) {
4538 /*
4539 * We have a non dir inode. Go through all deleted refs and
4540 * unlink them if they were not already overwritten by other
4541 * inodes.
4542 */
4543 list_for_each_entry(cur, &sctx->deleted_refs, list) {
4544 ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen,
4545 sctx->cur_ino, sctx->cur_inode_gen,
4546 cur->name, cur->name_len);
4547 if (ret < 0)
4548 goto out;
4549 if (!ret) {
4550 /*
4551 * If we orphanized any ancestor before, we need
4552 * to recompute the full path for deleted names,
4553 * since any such path was computed before we
4554 * processed any references and orphanized any
4555 * ancestor inode.
4556 */
4557 if (orphanized_ancestor) {
4558 ret = update_ref_path(sctx, cur);
4559 if (ret < 0)
4560 goto out;
4561 }
4562 ret = send_unlink(sctx, cur->full_path);
4563 if (ret < 0)
4564 goto out;
4565 }
4566 ret = dup_ref(cur, &check_dirs);
4567 if (ret < 0)
4568 goto out;
4569 }
4570 /*
4571 * If the inode is still orphan, unlink the orphan. This may
4572 * happen when a previous inode did overwrite the first ref
4573 * of this inode and no new refs were added for the current
4574 * inode. Unlinking does not mean that the inode is deleted in
4575 * all cases. There may still be links to this inode in other
4576 * places.
4577 */
4578 if (is_orphan) {
4579 ret = send_unlink(sctx, valid_path);
4580 if (ret < 0)
4581 goto out;
4582 }
4583 }
4584
4585 /*
4586 * We did collect all parent dirs where cur_inode was once located. We
4587 * now go through all these dirs and check if they are pending for
4588 * deletion and if it's finally possible to perform the rmdir now.
4589 * We also update the inode stats of the parent dirs here.
4590 */
4591 list_for_each_entry(cur, &check_dirs, list) {
4592 /*
4593 * In case we had refs into dirs that were not processed yet,
4594 * we don't need to do the utime and rmdir logic for these dirs.
4595 * The dir will be processed later.
4596 */
4597 if (cur->dir > sctx->cur_ino)
4598 continue;
4599
4600 ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen, NULL, NULL);
4601 if (ret < 0)
4602 goto out;
4603
4604 if (ret == inode_state_did_create ||
4605 ret == inode_state_no_change) {
4606 ret = cache_dir_utimes(sctx, cur->dir, cur->dir_gen);
4607 if (ret < 0)
4608 goto out;
4609 } else if (ret == inode_state_did_delete &&
4610 cur->dir != last_dir_ino_rm) {
4611 ret = can_rmdir(sctx, cur->dir, cur->dir_gen);
4612 if (ret < 0)
4613 goto out;
4614 if (ret) {
4615 ret = get_cur_path(sctx, cur->dir,
4616 cur->dir_gen, valid_path);
4617 if (ret < 0)
4618 goto out;
4619 ret = send_rmdir(sctx, valid_path);
4620 if (ret < 0)
4621 goto out;
4622 last_dir_ino_rm = cur->dir;
4623 }
4624 }
4625 }
4626
4627 ret = 0;
4628
4629 out:
4630 __free_recorded_refs(&check_dirs);
4631 free_recorded_refs(sctx);
4632 fs_path_free(valid_path);
4633 return ret;
4634 }
4635
4636 static int rbtree_ref_comp(const void *k, const struct rb_node *node)
4637 {
4638 const struct recorded_ref *data = k;
4639 const struct recorded_ref *ref = rb_entry(node, struct recorded_ref, node);
4640 int result;
4641
4642 if (data->dir > ref->dir)
4643 return 1;
4644 if (data->dir < ref->dir)
4645 return -1;
4646 if (data->dir_gen > ref->dir_gen)
4647 return 1;
4648 if (data->dir_gen < ref->dir_gen)
4649 return -1;
4650 if (data->name_len > ref->name_len)
4651 return 1;
4652 if (data->name_len < ref->name_len)
4653 return -1;
4654 result = strcmp(data->name, ref->name);
4655 if (result > 0)
4656 return 1;
4657 if (result < 0)
4658 return -1;
4659 return 0;
4660 }
4661
4662 static bool rbtree_ref_less(struct rb_node *node, const struct rb_node *parent)
4663 {
4664 const struct recorded_ref *entry = rb_entry(node, struct recorded_ref, node);
4665
4666 return rbtree_ref_comp(entry, parent) < 0;
4667 }
4668
4669 static int record_ref_in_tree(struct rb_root *root, struct list_head *refs,
4670 struct fs_path *name, u64 dir, u64 dir_gen,
4671 struct send_ctx *sctx)
4672 {
4673 int ret = 0;
4674 struct fs_path *path = NULL;
4675 struct recorded_ref *ref = NULL;
4676
4677 path = fs_path_alloc();
4678 if (!path) {
4679 ret = -ENOMEM;
4680 goto out;
4681 }
4682
4683 ref = recorded_ref_alloc();
4684 if (!ref) {
4685 ret = -ENOMEM;
4686 goto out;
4687 }
4688
4689 ret = get_cur_path(sctx, dir, dir_gen, path);
4690 if (ret < 0)
4691 goto out;
4692 ret = fs_path_add_path(path, name);
4693 if (ret < 0)
4694 goto out;
4695
4696 ref->dir = dir;
4697 ref->dir_gen = dir_gen;
4698 set_ref_path(ref, path);
4699 list_add_tail(&ref->list, refs);
4700 rb_add(&ref->node, root, rbtree_ref_less);
4701 ref->root = root;
4702 out:
4703 if (ret) {
4704 if (path && (!ref || !ref->full_path))
4705 fs_path_free(path);
4706 recorded_ref_free(ref);
4707 }
4708 return ret;
4709 }
4710
4711 static int record_new_ref_if_needed(int num, u64 dir, int index,
4712 struct fs_path *name, void *ctx)
4713 {
4714 int ret = 0;
4715 struct send_ctx *sctx = ctx;
4716 struct rb_node *node = NULL;
4717 struct recorded_ref data;
4718 struct recorded_ref *ref;
4719 u64 dir_gen;
4720
4721 ret = get_inode_gen(sctx->send_root, dir, &dir_gen);
4722 if (ret < 0)
4723 goto out;
4724
4725 data.dir = dir;
4726 data.dir_gen = dir_gen;
4727 set_ref_path(&data, name);
4728 node = rb_find(&data, &sctx->rbtree_deleted_refs, rbtree_ref_comp);
4729 if (node) {
4730 ref = rb_entry(node, struct recorded_ref, node);
4731 recorded_ref_free(ref);
4732 } else {
4733 ret = record_ref_in_tree(&sctx->rbtree_new_refs,
4734 &sctx->new_refs, name, dir, dir_gen,
4735 sctx);
4736 }
4737 out:
4738 return ret;
4739 }
4740
4741 static int record_deleted_ref_if_needed(int num, u64 dir, int index,
4742 struct fs_path *name, void *ctx)
4743 {
4744 int ret = 0;
4745 struct send_ctx *sctx = ctx;
4746 struct rb_node *node = NULL;
4747 struct recorded_ref data;
4748 struct recorded_ref *ref;
4749 u64 dir_gen;
4750
4751 ret = get_inode_gen(sctx->parent_root, dir, &dir_gen);
4752 if (ret < 0)
4753 goto out;
4754
4755 data.dir = dir;
4756 data.dir_gen = dir_gen;
4757 set_ref_path(&data, name);
4758 node = rb_find(&data, &sctx->rbtree_new_refs, rbtree_ref_comp);
4759 if (node) {
4760 ref = rb_entry(node, struct recorded_ref, node);
4761 recorded_ref_free(ref);
4762 } else {
4763 ret = record_ref_in_tree(&sctx->rbtree_deleted_refs,
4764 &sctx->deleted_refs, name, dir,
4765 dir_gen, sctx);
4766 }
4767 out:
4768 return ret;
4769 }
4770
4771 static int record_new_ref(struct send_ctx *sctx)
4772 {
4773 int ret;
4774
4775 ret = iterate_inode_ref(sctx->send_root, sctx->left_path,
4776 sctx->cmp_key, 0, record_new_ref_if_needed, sctx);
4777 if (ret < 0)
4778 goto out;
4779 ret = 0;
4780
4781 out:
4782 return ret;
4783 }
4784
4785 static int record_deleted_ref(struct send_ctx *sctx)
4786 {
4787 int ret;
4788
4789 ret = iterate_inode_ref(sctx->parent_root, sctx->right_path,
4790 sctx->cmp_key, 0, record_deleted_ref_if_needed,
4791 sctx);
4792 if (ret < 0)
4793 goto out;
4794 ret = 0;
4795
4796 out:
4797 return ret;
4798 }
4799
4800 static int record_changed_ref(struct send_ctx *sctx)
4801 {
4802 int ret = 0;
4803
4804 ret = iterate_inode_ref(sctx->send_root, sctx->left_path,
4805 sctx->cmp_key, 0, record_new_ref_if_needed, sctx);
4806 if (ret < 0)
4807 goto out;
4808 ret = iterate_inode_ref(sctx->parent_root, sctx->right_path,
4809 sctx->cmp_key, 0, record_deleted_ref_if_needed, sctx);
4810 if (ret < 0)
4811 goto out;
4812 ret = 0;
4813
4814 out:
4815 return ret;
4816 }
4817
4818 /*
4819 * Record and process all refs at once. Needed when an inode changes the
4820 * generation number, which means that it was deleted and recreated.
4821 */
4822 static int process_all_refs(struct send_ctx *sctx,
4823 enum btrfs_compare_tree_result cmd)
4824 {
4825 int ret = 0;
4826 int iter_ret = 0;
4827 struct btrfs_root *root;
4828 struct btrfs_path *path;
4829 struct btrfs_key key;
4830 struct btrfs_key found_key;
4831 iterate_inode_ref_t cb;
4832 int pending_move = 0;
4833
4834 path = alloc_path_for_send();
4835 if (!path)
4836 return -ENOMEM;
4837
4838 if (cmd == BTRFS_COMPARE_TREE_NEW) {
4839 root = sctx->send_root;
4840 cb = record_new_ref_if_needed;
4841 } else if (cmd == BTRFS_COMPARE_TREE_DELETED) {
4842 root = sctx->parent_root;
4843 cb = record_deleted_ref_if_needed;
4844 } else {
4845 btrfs_err(sctx->send_root->fs_info,
4846 "Wrong command %d in process_all_refs", cmd);
4847 ret = -EINVAL;
4848 goto out;
4849 }
4850
4851 key.objectid = sctx->cmp_key->objectid;
4852 key.type = BTRFS_INODE_REF_KEY;
4853 key.offset = 0;
4854 btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
4855 if (found_key.objectid != key.objectid ||
4856 (found_key.type != BTRFS_INODE_REF_KEY &&
4857 found_key.type != BTRFS_INODE_EXTREF_KEY))
4858 break;
4859
4860 ret = iterate_inode_ref(root, path, &found_key, 0, cb, sctx);
4861 if (ret < 0)
4862 goto out;
4863 }
4864 /* Catch error found during iteration */
4865 if (iter_ret < 0) {
4866 ret = iter_ret;
4867 goto out;
4868 }
4869 btrfs_release_path(path);
4870
4871 /*
4872 * We don't actually care about pending_move as we are simply
4873 * re-creating this inode and will be rename'ing it into place once we
4874 * rename the parent directory.
4875 */
4876 ret = process_recorded_refs(sctx, &pending_move);
4877 out:
4878 btrfs_free_path(path);
4879 return ret;
4880 }
4881
4882 static int send_set_xattr(struct send_ctx *sctx,
4883 struct fs_path *path,
4884 const char *name, int name_len,
4885 const char *data, int data_len)
4886 {
4887 int ret = 0;
4888
4889 ret = begin_cmd(sctx, BTRFS_SEND_C_SET_XATTR);
4890 if (ret < 0)
4891 goto out;
4892
4893 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
4894 TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
4895 TLV_PUT(sctx, BTRFS_SEND_A_XATTR_DATA, data, data_len);
4896
4897 ret = send_cmd(sctx);
4898
4899 tlv_put_failure:
4900 out:
4901 return ret;
4902 }
4903
4904 static int send_remove_xattr(struct send_ctx *sctx,
4905 struct fs_path *path,
4906 const char *name, int name_len)
4907 {
4908 int ret = 0;
4909
4910 ret = begin_cmd(sctx, BTRFS_SEND_C_REMOVE_XATTR);
4911 if (ret < 0)
4912 goto out;
4913
4914 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
4915 TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
4916
4917 ret = send_cmd(sctx);
4918
4919 tlv_put_failure:
4920 out:
4921 return ret;
4922 }
4923
4924 static int __process_new_xattr(int num, struct btrfs_key *di_key,
4925 const char *name, int name_len, const char *data,
4926 int data_len, void *ctx)
4927 {
4928 int ret;
4929 struct send_ctx *sctx = ctx;
4930 struct fs_path *p;
4931 struct posix_acl_xattr_header dummy_acl;
4932
4933 /* Capabilities are emitted by finish_inode_if_needed */
4934 if (!strncmp(name, XATTR_NAME_CAPS, name_len))
4935 return 0;
4936
4937 p = fs_path_alloc();
4938 if (!p)
4939 return -ENOMEM;
4940
4941 /*
4942 * This hack is needed because empty acls are stored as zero byte
4943 * data in xattrs. Problem with that is, that receiving these zero byte
4944 * acls will fail later. To fix this, we send a dummy acl list that
4945 * only contains the version number and no entries.
4946 */
4947 if (!strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS, name_len) ||
4948 !strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT, name_len)) {
4949 if (data_len == 0) {
4950 dummy_acl.a_version =
4951 cpu_to_le32(POSIX_ACL_XATTR_VERSION);
4952 data = (char *)&dummy_acl;
4953 data_len = sizeof(dummy_acl);
4954 }
4955 }
4956
4957 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
4958 if (ret < 0)
4959 goto out;
4960
4961 ret = send_set_xattr(sctx, p, name, name_len, data, data_len);
4962
4963 out:
4964 fs_path_free(p);
4965 return ret;
4966 }
4967
4968 static int __process_deleted_xattr(int num, struct btrfs_key *di_key,
4969 const char *name, int name_len,
4970 const char *data, int data_len, void *ctx)
4971 {
4972 int ret;
4973 struct send_ctx *sctx = ctx;
4974 struct fs_path *p;
4975
4976 p = fs_path_alloc();
4977 if (!p)
4978 return -ENOMEM;
4979
4980 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
4981 if (ret < 0)
4982 goto out;
4983
4984 ret = send_remove_xattr(sctx, p, name, name_len);
4985
4986 out:
4987 fs_path_free(p);
4988 return ret;
4989 }
4990
4991 static int process_new_xattr(struct send_ctx *sctx)
4992 {
4993 int ret = 0;
4994
4995 ret = iterate_dir_item(sctx->send_root, sctx->left_path,
4996 __process_new_xattr, sctx);
4997
4998 return ret;
4999 }
5000
5001 static int process_deleted_xattr(struct send_ctx *sctx)
5002 {
5003 return iterate_dir_item(sctx->parent_root, sctx->right_path,
5004 __process_deleted_xattr, sctx);
5005 }
5006
5007 struct find_xattr_ctx {
5008 const char *name;
5009 int name_len;
5010 int found_idx;
5011 char *found_data;
5012 int found_data_len;
5013 };
5014
5015 static int __find_xattr(int num, struct btrfs_key *di_key, const char *name,
5016 int name_len, const char *data, int data_len, void *vctx)
5017 {
5018 struct find_xattr_ctx *ctx = vctx;
5019
5020 if (name_len == ctx->name_len &&
5021 strncmp(name, ctx->name, name_len) == 0) {
5022 ctx->found_idx = num;
5023 ctx->found_data_len = data_len;
5024 ctx->found_data = kmemdup(data, data_len, GFP_KERNEL);
5025 if (!ctx->found_data)
5026 return -ENOMEM;
5027 return 1;
5028 }
5029 return 0;
5030 }
5031
5032 static int find_xattr(struct btrfs_root *root,
5033 struct btrfs_path *path,
5034 struct btrfs_key *key,
5035 const char *name, int name_len,
5036 char **data, int *data_len)
5037 {
5038 int ret;
5039 struct find_xattr_ctx ctx;
5040
5041 ctx.name = name;
5042 ctx.name_len = name_len;
5043 ctx.found_idx = -1;
5044 ctx.found_data = NULL;
5045 ctx.found_data_len = 0;
5046
5047 ret = iterate_dir_item(root, path, __find_xattr, &ctx);
5048 if (ret < 0)
5049 return ret;
5050
5051 if (ctx.found_idx == -1)
5052 return -ENOENT;
5053 if (data) {
5054 *data = ctx.found_data;
5055 *data_len = ctx.found_data_len;
5056 } else {
5057 kfree(ctx.found_data);
5058 }
5059 return ctx.found_idx;
5060 }
5061
5062
5063 static int __process_changed_new_xattr(int num, struct btrfs_key *di_key,
5064 const char *name, int name_len,
5065 const char *data, int data_len,
5066 void *ctx)
5067 {
5068 int ret;
5069 struct send_ctx *sctx = ctx;
5070 char *found_data = NULL;
5071 int found_data_len = 0;
5072
5073 ret = find_xattr(sctx->parent_root, sctx->right_path,
5074 sctx->cmp_key, name, name_len, &found_data,
5075 &found_data_len);
5076 if (ret == -ENOENT) {
5077 ret = __process_new_xattr(num, di_key, name, name_len, data,
5078 data_len, ctx);
5079 } else if (ret >= 0) {
5080 if (data_len != found_data_len ||
5081 memcmp(data, found_data, data_len)) {
5082 ret = __process_new_xattr(num, di_key, name, name_len,
5083 data, data_len, ctx);
5084 } else {
5085 ret = 0;
5086 }
5087 }
5088
5089 kfree(found_data);
5090 return ret;
5091 }
5092
5093 static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key,
5094 const char *name, int name_len,
5095 const char *data, int data_len,
5096 void *ctx)
5097 {
5098 int ret;
5099 struct send_ctx *sctx = ctx;
5100
5101 ret = find_xattr(sctx->send_root, sctx->left_path, sctx->cmp_key,
5102 name, name_len, NULL, NULL);
5103 if (ret == -ENOENT)
5104 ret = __process_deleted_xattr(num, di_key, name, name_len, data,
5105 data_len, ctx);
5106 else if (ret >= 0)
5107 ret = 0;
5108
5109 return ret;
5110 }
5111
5112 static int process_changed_xattr(struct send_ctx *sctx)
5113 {
5114 int ret = 0;
5115
5116 ret = iterate_dir_item(sctx->send_root, sctx->left_path,
5117 __process_changed_new_xattr, sctx);
5118 if (ret < 0)
5119 goto out;
5120 ret = iterate_dir_item(sctx->parent_root, sctx->right_path,
5121 __process_changed_deleted_xattr, sctx);
5122
5123 out:
5124 return ret;
5125 }
5126
5127 static int process_all_new_xattrs(struct send_ctx *sctx)
5128 {
5129 int ret = 0;
5130 int iter_ret = 0;
5131 struct btrfs_root *root;
5132 struct btrfs_path *path;
5133 struct btrfs_key key;
5134 struct btrfs_key found_key;
5135
5136 path = alloc_path_for_send();
5137 if (!path)
5138 return -ENOMEM;
5139
5140 root = sctx->send_root;
5141
5142 key.objectid = sctx->cmp_key->objectid;
5143 key.type = BTRFS_XATTR_ITEM_KEY;
5144 key.offset = 0;
5145 btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
5146 if (found_key.objectid != key.objectid ||
5147 found_key.type != key.type) {
5148 ret = 0;
5149 break;
5150 }
5151
5152 ret = iterate_dir_item(root, path, __process_new_xattr, sctx);
5153 if (ret < 0)
5154 break;
5155 }
5156 /* Catch error found during iteration */
5157 if (iter_ret < 0)
5158 ret = iter_ret;
5159
5160 btrfs_free_path(path);
5161 return ret;
5162 }
5163
5164 static int send_verity(struct send_ctx *sctx, struct fs_path *path,
5165 struct fsverity_descriptor *desc)
5166 {
5167 int ret;
5168
5169 ret = begin_cmd(sctx, BTRFS_SEND_C_ENABLE_VERITY);
5170 if (ret < 0)
5171 goto out;
5172
5173 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
5174 TLV_PUT_U8(sctx, BTRFS_SEND_A_VERITY_ALGORITHM,
5175 le8_to_cpu(desc->hash_algorithm));
5176 TLV_PUT_U32(sctx, BTRFS_SEND_A_VERITY_BLOCK_SIZE,
5177 1U << le8_to_cpu(desc->log_blocksize));
5178 TLV_PUT(sctx, BTRFS_SEND_A_VERITY_SALT_DATA, desc->salt,
5179 le8_to_cpu(desc->salt_size));
5180 TLV_PUT(sctx, BTRFS_SEND_A_VERITY_SIG_DATA, desc->signature,
5181 le32_to_cpu(desc->sig_size));
5182
5183 ret = send_cmd(sctx);
5184
5185 tlv_put_failure:
5186 out:
5187 return ret;
5188 }
5189
5190 static int process_verity(struct send_ctx *sctx)
5191 {
5192 int ret = 0;
5193 struct inode *inode;
5194 struct fs_path *p;
5195
5196 inode = btrfs_iget(sctx->cur_ino, sctx->send_root);
5197 if (IS_ERR(inode))
5198 return PTR_ERR(inode);
5199
5200 ret = btrfs_get_verity_descriptor(inode, NULL, 0);
5201 if (ret < 0)
5202 goto iput;
5203
5204 if (ret > FS_VERITY_MAX_DESCRIPTOR_SIZE) {
5205 ret = -EMSGSIZE;
5206 goto iput;
5207 }
5208 if (!sctx->verity_descriptor) {
5209 sctx->verity_descriptor = kvmalloc(FS_VERITY_MAX_DESCRIPTOR_SIZE,
5210 GFP_KERNEL);
5211 if (!sctx->verity_descriptor) {
5212 ret = -ENOMEM;
5213 goto iput;
5214 }
5215 }
5216
5217 ret = btrfs_get_verity_descriptor(inode, sctx->verity_descriptor, ret);
5218 if (ret < 0)
5219 goto iput;
5220
5221 p = fs_path_alloc();
5222 if (!p) {
5223 ret = -ENOMEM;
5224 goto iput;
5225 }
5226 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5227 if (ret < 0)
5228 goto free_path;
5229
5230 ret = send_verity(sctx, p, sctx->verity_descriptor);
5231 if (ret < 0)
5232 goto free_path;
5233
5234 free_path:
5235 fs_path_free(p);
5236 iput:
5237 iput(inode);
5238 return ret;
5239 }
5240
5241 static inline u64 max_send_read_size(const struct send_ctx *sctx)
5242 {
5243 return sctx->send_max_size - SZ_16K;
5244 }
5245
5246 static int put_data_header(struct send_ctx *sctx, u32 len)
5247 {
5248 if (WARN_ON_ONCE(sctx->put_data))
5249 return -EINVAL;
5250 sctx->put_data = true;
5251 if (sctx->proto >= 2) {
5252 /*
5253 * Since v2, the data attribute header doesn't include a length,
5254 * it is implicitly to the end of the command.
5255 */
5256 if (sctx->send_max_size - sctx->send_size < sizeof(__le16) + len)
5257 return -EOVERFLOW;
5258 put_unaligned_le16(BTRFS_SEND_A_DATA, sctx->send_buf + sctx->send_size);
5259 sctx->send_size += sizeof(__le16);
5260 } else {
5261 struct btrfs_tlv_header *hdr;
5262
5263 if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len)
5264 return -EOVERFLOW;
5265 hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size);
5266 put_unaligned_le16(BTRFS_SEND_A_DATA, &hdr->tlv_type);
5267 put_unaligned_le16(len, &hdr->tlv_len);
5268 sctx->send_size += sizeof(*hdr);
5269 }
5270 return 0;
5271 }
5272
5273 static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
5274 {
5275 struct btrfs_root *root = sctx->send_root;
5276 struct btrfs_fs_info *fs_info = root->fs_info;
5277 struct folio *folio;
5278 pgoff_t index = offset >> PAGE_SHIFT;
5279 pgoff_t last_index;
5280 unsigned pg_offset = offset_in_page(offset);
5281 struct address_space *mapping = sctx->cur_inode->i_mapping;
5282 int ret;
5283
5284 ret = put_data_header(sctx, len);
5285 if (ret)
5286 return ret;
5287
5288 last_index = (offset + len - 1) >> PAGE_SHIFT;
5289
5290 while (index <= last_index) {
5291 unsigned cur_len = min_t(unsigned, len,
5292 PAGE_SIZE - pg_offset);
5293
5294 folio = filemap_lock_folio(mapping, index);
5295 if (IS_ERR(folio)) {
5296 page_cache_sync_readahead(mapping,
5297 &sctx->ra, NULL, index,
5298 last_index + 1 - index);
5299
5300 folio = filemap_grab_folio(mapping, index);
5301 if (IS_ERR(folio)) {
5302 ret = PTR_ERR(folio);
5303 break;
5304 }
5305 }
5306
5307 WARN_ON(folio_order(folio));
5308
5309 if (folio_test_readahead(folio))
5310 page_cache_async_readahead(mapping, &sctx->ra, NULL, folio,
5311 last_index + 1 - index);
5312
5313 if (!folio_test_uptodate(folio)) {
5314 btrfs_read_folio(NULL, folio);
5315 folio_lock(folio);
5316 if (!folio_test_uptodate(folio)) {
5317 folio_unlock(folio);
5318 btrfs_err(fs_info,
5319 "send: IO error at offset %llu for inode %llu root %llu",
5320 folio_pos(folio), sctx->cur_ino,
5321 btrfs_root_id(sctx->send_root));
5322 folio_put(folio);
5323 ret = -EIO;
5324 break;
5325 }
5326 }
5327
5328 memcpy_from_folio(sctx->send_buf + sctx->send_size, folio,
5329 pg_offset, cur_len);
5330 folio_unlock(folio);
5331 folio_put(folio);
5332 index++;
5333 pg_offset = 0;
5334 len -= cur_len;
5335 sctx->send_size += cur_len;
5336 }
5337
5338 return ret;
5339 }
5340
5341 /*
5342 * Read some bytes from the current inode/file and send a write command to
5343 * user space.
5344 */
5345 static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
5346 {
5347 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
5348 int ret = 0;
5349 struct fs_path *p;
5350
5351 p = fs_path_alloc();
5352 if (!p)
5353 return -ENOMEM;
5354
5355 btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len);
5356
5357 ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
5358 if (ret < 0)
5359 goto out;
5360
5361 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5362 if (ret < 0)
5363 goto out;
5364
5365 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
5366 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5367 ret = put_file_data(sctx, offset, len);
5368 if (ret < 0)
5369 goto out;
5370
5371 ret = send_cmd(sctx);
5372
5373 tlv_put_failure:
5374 out:
5375 fs_path_free(p);
5376 return ret;
5377 }
5378
5379 /*
5380 * Send a clone command to user space.
5381 */
5382 static int send_clone(struct send_ctx *sctx,
5383 u64 offset, u32 len,
5384 struct clone_root *clone_root)
5385 {
5386 int ret = 0;
5387 struct fs_path *p;
5388 u64 gen;
5389
5390 btrfs_debug(sctx->send_root->fs_info,
5391 "send_clone offset=%llu, len=%d, clone_root=%llu, clone_inode=%llu, clone_offset=%llu",
5392 offset, len, btrfs_root_id(clone_root->root),
5393 clone_root->ino, clone_root->offset);
5394
5395 p = fs_path_alloc();
5396 if (!p)
5397 return -ENOMEM;
5398
5399 ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE);
5400 if (ret < 0)
5401 goto out;
5402
5403 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5404 if (ret < 0)
5405 goto out;
5406
5407 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5408 TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len);
5409 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
5410
5411 if (clone_root->root == sctx->send_root) {
5412 ret = get_inode_gen(sctx->send_root, clone_root->ino, &gen);
5413 if (ret < 0)
5414 goto out;
5415 ret = get_cur_path(sctx, clone_root->ino, gen, p);
5416 } else {
5417 ret = get_inode_path(clone_root->root, clone_root->ino, p);
5418 }
5419 if (ret < 0)
5420 goto out;
5421
5422 /*
5423 * If the parent we're using has a received_uuid set then use that as
5424 * our clone source as that is what we will look for when doing a
5425 * receive.
5426 *
5427 * This covers the case that we create a snapshot off of a received
5428 * subvolume and then use that as the parent and try to receive on a
5429 * different host.
5430 */
5431 if (!btrfs_is_empty_uuid(clone_root->root->root_item.received_uuid))
5432 TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
5433 clone_root->root->root_item.received_uuid);
5434 else
5435 TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
5436 clone_root->root->root_item.uuid);
5437 TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
5438 btrfs_root_ctransid(&clone_root->root->root_item));
5439 TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p);
5440 TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET,
5441 clone_root->offset);
5442
5443 ret = send_cmd(sctx);
5444
5445 tlv_put_failure:
5446 out:
5447 fs_path_free(p);
5448 return ret;
5449 }
5450
5451 /*
5452 * Send an update extent command to user space.
5453 */
5454 static int send_update_extent(struct send_ctx *sctx,
5455 u64 offset, u32 len)
5456 {
5457 int ret = 0;
5458 struct fs_path *p;
5459
5460 p = fs_path_alloc();
5461 if (!p)
5462 return -ENOMEM;
5463
5464 ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT);
5465 if (ret < 0)
5466 goto out;
5467
5468 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5469 if (ret < 0)
5470 goto out;
5471
5472 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
5473 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5474 TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len);
5475
5476 ret = send_cmd(sctx);
5477
5478 tlv_put_failure:
5479 out:
5480 fs_path_free(p);
5481 return ret;
5482 }
5483
5484 static int send_hole(struct send_ctx *sctx, u64 end)
5485 {
5486 struct fs_path *p = NULL;
5487 u64 read_size = max_send_read_size(sctx);
5488 u64 offset = sctx->cur_inode_last_extent;
5489 int ret = 0;
5490
5491 /*
5492 * A hole that starts at EOF or beyond it. Since we do not yet support
5493 * fallocate (for extent preallocation and hole punching), sending a
5494 * write of zeroes starting at EOF or beyond would later require issuing
5495 * a truncate operation which would undo the write and achieve nothing.
5496 */
5497 if (offset >= sctx->cur_inode_size)
5498 return 0;
5499
5500 /*
5501 * Don't go beyond the inode's i_size due to prealloc extents that start
5502 * after the i_size.
5503 */
5504 end = min_t(u64, end, sctx->cur_inode_size);
5505
5506 if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
5507 return send_update_extent(sctx, offset, end - offset);
5508
5509 p = fs_path_alloc();
5510 if (!p)
5511 return -ENOMEM;
5512 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5513 if (ret < 0)
5514 goto tlv_put_failure;
5515 while (offset < end) {
5516 u64 len = min(end - offset, read_size);
5517
5518 ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
5519 if (ret < 0)
5520 break;
5521 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
5522 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5523 ret = put_data_header(sctx, len);
5524 if (ret < 0)
5525 break;
5526 memset(sctx->send_buf + sctx->send_size, 0, len);
5527 sctx->send_size += len;
5528 ret = send_cmd(sctx);
5529 if (ret < 0)
5530 break;
5531 offset += len;
5532 }
5533 sctx->cur_inode_next_write_offset = offset;
5534 tlv_put_failure:
5535 fs_path_free(p);
5536 return ret;
5537 }
5538
5539 static int send_encoded_inline_extent(struct send_ctx *sctx,
5540 struct btrfs_path *path, u64 offset,
5541 u64 len)
5542 {
5543 struct btrfs_root *root = sctx->send_root;
5544 struct btrfs_fs_info *fs_info = root->fs_info;
5545 struct inode *inode;
5546 struct fs_path *fspath;
5547 struct extent_buffer *leaf = path->nodes[0];
5548 struct btrfs_key key;
5549 struct btrfs_file_extent_item *ei;
5550 u64 ram_bytes;
5551 size_t inline_size;
5552 int ret;
5553
5554 inode = btrfs_iget(sctx->cur_ino, root);
5555 if (IS_ERR(inode))
5556 return PTR_ERR(inode);
5557
5558 fspath = fs_path_alloc();
5559 if (!fspath) {
5560 ret = -ENOMEM;
5561 goto out;
5562 }
5563
5564 ret = begin_cmd(sctx, BTRFS_SEND_C_ENCODED_WRITE);
5565 if (ret < 0)
5566 goto out;
5567
5568 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath);
5569 if (ret < 0)
5570 goto out;
5571
5572 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
5573 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item);
5574 ram_bytes = btrfs_file_extent_ram_bytes(leaf, ei);
5575 inline_size = btrfs_file_extent_inline_item_len(leaf, path->slots[0]);
5576
5577 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, fspath);
5578 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5579 TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN,
5580 min(key.offset + ram_bytes - offset, len));
5581 TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN, ram_bytes);
5582 TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET, offset - key.offset);
5583 ret = btrfs_encoded_io_compression_from_extent(fs_info,
5584 btrfs_file_extent_compression(leaf, ei));
5585 if (ret < 0)
5586 goto out;
5587 TLV_PUT_U32(sctx, BTRFS_SEND_A_COMPRESSION, ret);
5588
5589 ret = put_data_header(sctx, inline_size);
5590 if (ret < 0)
5591 goto out;
5592 read_extent_buffer(leaf, sctx->send_buf + sctx->send_size,
5593 btrfs_file_extent_inline_start(ei), inline_size);
5594 sctx->send_size += inline_size;
5595
5596 ret = send_cmd(sctx);
5597
5598 tlv_put_failure:
5599 out:
5600 fs_path_free(fspath);
5601 iput(inode);
5602 return ret;
5603 }
5604
5605 static int send_encoded_extent(struct send_ctx *sctx, struct btrfs_path *path,
5606 u64 offset, u64 len)
5607 {
5608 struct btrfs_root *root = sctx->send_root;
5609 struct btrfs_fs_info *fs_info = root->fs_info;
5610 struct inode *inode;
5611 struct fs_path *fspath;
5612 struct extent_buffer *leaf = path->nodes[0];
5613 struct btrfs_key key;
5614 struct btrfs_file_extent_item *ei;
5615 u64 disk_bytenr, disk_num_bytes;
5616 u32 data_offset;
5617 struct btrfs_cmd_header *hdr;
5618 u32 crc;
5619 int ret;
5620
5621 inode = btrfs_iget(sctx->cur_ino, root);
5622 if (IS_ERR(inode))
5623 return PTR_ERR(inode);
5624
5625 fspath = fs_path_alloc();
5626 if (!fspath) {
5627 ret = -ENOMEM;
5628 goto out;
5629 }
5630
5631 ret = begin_cmd(sctx, BTRFS_SEND_C_ENCODED_WRITE);
5632 if (ret < 0)
5633 goto out;
5634
5635 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath);
5636 if (ret < 0)
5637 goto out;
5638
5639 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
5640 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item);
5641 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, ei);
5642 disk_num_bytes = btrfs_file_extent_disk_num_bytes(leaf, ei);
5643
5644 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, fspath);
5645 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5646 TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN,
5647 min(key.offset + btrfs_file_extent_num_bytes(leaf, ei) - offset,
5648 len));
5649 TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN,
5650 btrfs_file_extent_ram_bytes(leaf, ei));
5651 TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET,
5652 offset - key.offset + btrfs_file_extent_offset(leaf, ei));
5653 ret = btrfs_encoded_io_compression_from_extent(fs_info,
5654 btrfs_file_extent_compression(leaf, ei));
5655 if (ret < 0)
5656 goto out;
5657 TLV_PUT_U32(sctx, BTRFS_SEND_A_COMPRESSION, ret);
5658 TLV_PUT_U32(sctx, BTRFS_SEND_A_ENCRYPTION, 0);
5659
5660 ret = put_data_header(sctx, disk_num_bytes);
5661 if (ret < 0)
5662 goto out;
5663
5664 /*
5665 * We want to do I/O directly into the send buffer, so get the next page
5666 * boundary in the send buffer. This means that there may be a gap
5667 * between the beginning of the command and the file data.
5668 */
5669 data_offset = PAGE_ALIGN(sctx->send_size);
5670 if (data_offset > sctx->send_max_size ||
5671 sctx->send_max_size - data_offset < disk_num_bytes) {
5672 ret = -EOVERFLOW;
5673 goto out;
5674 }
5675
5676 /*
5677 * Note that send_buf is a mapping of send_buf_pages, so this is really
5678 * reading into send_buf.
5679 */
5680 ret = btrfs_encoded_read_regular_fill_pages(BTRFS_I(inode), offset,
5681 disk_bytenr, disk_num_bytes,
5682 sctx->send_buf_pages +
5683 (data_offset >> PAGE_SHIFT));
5684 if (ret)
5685 goto out;
5686
5687 hdr = (struct btrfs_cmd_header *)sctx->send_buf;
5688 hdr->len = cpu_to_le32(sctx->send_size + disk_num_bytes - sizeof(*hdr));
5689 hdr->crc = 0;
5690 crc = crc32c(0, sctx->send_buf, sctx->send_size);
5691 crc = crc32c(crc, sctx->send_buf + data_offset, disk_num_bytes);
5692 hdr->crc = cpu_to_le32(crc);
5693
5694 ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size,
5695 &sctx->send_off);
5696 if (!ret) {
5697 ret = write_buf(sctx->send_filp, sctx->send_buf + data_offset,
5698 disk_num_bytes, &sctx->send_off);
5699 }
5700 sctx->send_size = 0;
5701 sctx->put_data = false;
5702
5703 tlv_put_failure:
5704 out:
5705 fs_path_free(fspath);
5706 iput(inode);
5707 return ret;
5708 }
5709
5710 static int send_extent_data(struct send_ctx *sctx, struct btrfs_path *path,
5711 const u64 offset, const u64 len)
5712 {
5713 const u64 end = offset + len;
5714 struct extent_buffer *leaf = path->nodes[0];
5715 struct btrfs_file_extent_item *ei;
5716 u64 read_size = max_send_read_size(sctx);
5717 u64 sent = 0;
5718
5719 if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
5720 return send_update_extent(sctx, offset, len);
5721
5722 ei = btrfs_item_ptr(leaf, path->slots[0],
5723 struct btrfs_file_extent_item);
5724 if ((sctx->flags & BTRFS_SEND_FLAG_COMPRESSED) &&
5725 btrfs_file_extent_compression(leaf, ei) != BTRFS_COMPRESS_NONE) {
5726 bool is_inline = (btrfs_file_extent_type(leaf, ei) ==
5727 BTRFS_FILE_EXTENT_INLINE);
5728
5729 /*
5730 * Send the compressed extent unless the compressed data is
5731 * larger than the decompressed data. This can happen if we're
5732 * not sending the entire extent, either because it has been
5733 * partially overwritten/truncated or because this is a part of
5734 * the extent that we couldn't clone in clone_range().
5735 */
5736 if (is_inline &&
5737 btrfs_file_extent_inline_item_len(leaf,
5738 path->slots[0]) <= len) {
5739 return send_encoded_inline_extent(sctx, path, offset,
5740 len);
5741 } else if (!is_inline &&
5742 btrfs_file_extent_disk_num_bytes(leaf, ei) <= len) {
5743 return send_encoded_extent(sctx, path, offset, len);
5744 }
5745 }
5746
5747 if (sctx->cur_inode == NULL) {
5748 struct btrfs_root *root = sctx->send_root;
5749
5750 sctx->cur_inode = btrfs_iget(sctx->cur_ino, root);
5751 if (IS_ERR(sctx->cur_inode)) {
5752 int err = PTR_ERR(sctx->cur_inode);
5753
5754 sctx->cur_inode = NULL;
5755 return err;
5756 }
5757 memset(&sctx->ra, 0, sizeof(struct file_ra_state));
5758 file_ra_state_init(&sctx->ra, sctx->cur_inode->i_mapping);
5759
5760 /*
5761 * It's very likely there are no pages from this inode in the page
5762 * cache, so after reading extents and sending their data, we clean
5763 * the page cache to avoid trashing the page cache (adding pressure
5764 * to the page cache and forcing eviction of other data more useful
5765 * for applications).
5766 *
5767 * We decide if we should clean the page cache simply by checking
5768 * if the inode's mapping nrpages is 0 when we first open it, and
5769 * not by using something like filemap_range_has_page() before
5770 * reading an extent because when we ask the readahead code to
5771 * read a given file range, it may (and almost always does) read
5772 * pages from beyond that range (see the documentation for
5773 * page_cache_sync_readahead()), so it would not be reliable,
5774 * because after reading the first extent future calls to
5775 * filemap_range_has_page() would return true because the readahead
5776 * on the previous extent resulted in reading pages of the current
5777 * extent as well.
5778 */
5779 sctx->clean_page_cache = (sctx->cur_inode->i_mapping->nrpages == 0);
5780 sctx->page_cache_clear_start = round_down(offset, PAGE_SIZE);
5781 }
5782
5783 while (sent < len) {
5784 u64 size = min(len - sent, read_size);
5785 int ret;
5786
5787 ret = send_write(sctx, offset + sent, size);
5788 if (ret < 0)
5789 return ret;
5790 sent += size;
5791 }
5792
5793 if (sctx->clean_page_cache && PAGE_ALIGNED(end)) {
5794 /*
5795 * Always operate only on ranges that are a multiple of the page
5796 * size. This is not only to prevent zeroing parts of a page in
5797 * the case of subpage sector size, but also to guarantee we evict
5798 * pages, as passing a range that is smaller than page size does
5799 * not evict the respective page (only zeroes part of its content).
5800 *
5801 * Always start from the end offset of the last range cleared.
5802 * This is because the readahead code may (and very often does)
5803 * reads pages beyond the range we request for readahead. So if
5804 * we have an extent layout like this:
5805 *
5806 * [ extent A ] [ extent B ] [ extent C ]
5807 *
5808 * When we ask page_cache_sync_readahead() to read extent A, it
5809 * may also trigger reads for pages of extent B. If we are doing
5810 * an incremental send and extent B has not changed between the
5811 * parent and send snapshots, some or all of its pages may end
5812 * up being read and placed in the page cache. So when truncating
5813 * the page cache we always start from the end offset of the
5814 * previously processed extent up to the end of the current
5815 * extent.
5816 */
5817 truncate_inode_pages_range(&sctx->cur_inode->i_data,
5818 sctx->page_cache_clear_start,
5819 end - 1);
5820 sctx->page_cache_clear_start = end;
5821 }
5822
5823 return 0;
5824 }
5825
5826 /*
5827 * Search for a capability xattr related to sctx->cur_ino. If the capability is
5828 * found, call send_set_xattr function to emit it.
5829 *
5830 * Return 0 if there isn't a capability, or when the capability was emitted
5831 * successfully, or < 0 if an error occurred.
5832 */
5833 static int send_capabilities(struct send_ctx *sctx)
5834 {
5835 struct fs_path *fspath = NULL;
5836 struct btrfs_path *path;
5837 struct btrfs_dir_item *di;
5838 struct extent_buffer *leaf;
5839 unsigned long data_ptr;
5840 char *buf = NULL;
5841 int buf_len;
5842 int ret = 0;
5843
5844 path = alloc_path_for_send();
5845 if (!path)
5846 return -ENOMEM;
5847
5848 di = btrfs_lookup_xattr(NULL, sctx->send_root, path, sctx->cur_ino,
5849 XATTR_NAME_CAPS, strlen(XATTR_NAME_CAPS), 0);
5850 if (!di) {
5851 /* There is no xattr for this inode */
5852 goto out;
5853 } else if (IS_ERR(di)) {
5854 ret = PTR_ERR(di);
5855 goto out;
5856 }
5857
5858 leaf = path->nodes[0];
5859 buf_len = btrfs_dir_data_len(leaf, di);
5860
5861 fspath = fs_path_alloc();
5862 buf = kmalloc(buf_len, GFP_KERNEL);
5863 if (!fspath || !buf) {
5864 ret = -ENOMEM;
5865 goto out;
5866 }
5867
5868 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath);
5869 if (ret < 0)
5870 goto out;
5871
5872 data_ptr = (unsigned long)(di + 1) + btrfs_dir_name_len(leaf, di);
5873 read_extent_buffer(leaf, buf, data_ptr, buf_len);
5874
5875 ret = send_set_xattr(sctx, fspath, XATTR_NAME_CAPS,
5876 strlen(XATTR_NAME_CAPS), buf, buf_len);
5877 out:
5878 kfree(buf);
5879 fs_path_free(fspath);
5880 btrfs_free_path(path);
5881 return ret;
5882 }
5883
5884 static int clone_range(struct send_ctx *sctx, struct btrfs_path *dst_path,
5885 struct clone_root *clone_root, const u64 disk_byte,
5886 u64 data_offset, u64 offset, u64 len)
5887 {
5888 struct btrfs_path *path;
5889 struct btrfs_key key;
5890 int ret;
5891 struct btrfs_inode_info info;
5892 u64 clone_src_i_size = 0;
5893
5894 /*
5895 * Prevent cloning from a zero offset with a length matching the sector
5896 * size because in some scenarios this will make the receiver fail.
5897 *
5898 * For example, if in the source filesystem the extent at offset 0
5899 * has a length of sectorsize and it was written using direct IO, then
5900 * it can never be an inline extent (even if compression is enabled).
5901 * Then this extent can be cloned in the original filesystem to a non
5902 * zero file offset, but it may not be possible to clone in the
5903 * destination filesystem because it can be inlined due to compression
5904 * on the destination filesystem (as the receiver's write operations are
5905 * always done using buffered IO). The same happens when the original
5906 * filesystem does not have compression enabled but the destination
5907 * filesystem has.
5908 */
5909 if (clone_root->offset == 0 &&
5910 len == sctx->send_root->fs_info->sectorsize)
5911 return send_extent_data(sctx, dst_path, offset, len);
5912
5913 path = alloc_path_for_send();
5914 if (!path)
5915 return -ENOMEM;
5916
5917 /*
5918 * There are inodes that have extents that lie behind its i_size. Don't
5919 * accept clones from these extents.
5920 */
5921 ret = get_inode_info(clone_root->root, clone_root->ino, &info);
5922 btrfs_release_path(path);
5923 if (ret < 0)
5924 goto out;
5925 clone_src_i_size = info.size;
5926
5927 /*
5928 * We can't send a clone operation for the entire range if we find
5929 * extent items in the respective range in the source file that
5930 * refer to different extents or if we find holes.
5931 * So check for that and do a mix of clone and regular write/copy
5932 * operations if needed.
5933 *
5934 * Example:
5935 *
5936 * mkfs.btrfs -f /dev/sda
5937 * mount /dev/sda /mnt
5938 * xfs_io -f -c "pwrite -S 0xaa 0K 100K" /mnt/foo
5939 * cp --reflink=always /mnt/foo /mnt/bar
5940 * xfs_io -c "pwrite -S 0xbb 50K 50K" /mnt/foo
5941 * btrfs subvolume snapshot -r /mnt /mnt/snap
5942 *
5943 * If when we send the snapshot and we are processing file bar (which
5944 * has a higher inode number than foo) we blindly send a clone operation
5945 * for the [0, 100K[ range from foo to bar, the receiver ends up getting
5946 * a file bar that matches the content of file foo - iow, doesn't match
5947 * the content from bar in the original filesystem.
5948 */
5949 key.objectid = clone_root->ino;
5950 key.type = BTRFS_EXTENT_DATA_KEY;
5951 key.offset = clone_root->offset;
5952 ret = btrfs_search_slot(NULL, clone_root->root, &key, path, 0, 0);
5953 if (ret < 0)
5954 goto out;
5955 if (ret > 0 && path->slots[0] > 0) {
5956 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1);
5957 if (key.objectid == clone_root->ino &&
5958 key.type == BTRFS_EXTENT_DATA_KEY)
5959 path->slots[0]--;
5960 }
5961
5962 while (true) {
5963 struct extent_buffer *leaf = path->nodes[0];
5964 int slot = path->slots[0];
5965 struct btrfs_file_extent_item *ei;
5966 u8 type;
5967 u64 ext_len;
5968 u64 clone_len;
5969 u64 clone_data_offset;
5970 bool crossed_src_i_size = false;
5971
5972 if (slot >= btrfs_header_nritems(leaf)) {
5973 ret = btrfs_next_leaf(clone_root->root, path);
5974 if (ret < 0)
5975 goto out;
5976 else if (ret > 0)
5977 break;
5978 continue;
5979 }
5980
5981 btrfs_item_key_to_cpu(leaf, &key, slot);
5982
5983 /*
5984 * We might have an implicit trailing hole (NO_HOLES feature
5985 * enabled). We deal with it after leaving this loop.
5986 */
5987 if (key.objectid != clone_root->ino ||
5988 key.type != BTRFS_EXTENT_DATA_KEY)
5989 break;
5990
5991 ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5992 type = btrfs_file_extent_type(leaf, ei);
5993 if (type == BTRFS_FILE_EXTENT_INLINE) {
5994 ext_len = btrfs_file_extent_ram_bytes(leaf, ei);
5995 ext_len = PAGE_ALIGN(ext_len);
5996 } else {
5997 ext_len = btrfs_file_extent_num_bytes(leaf, ei);
5998 }
5999
6000 if (key.offset + ext_len <= clone_root->offset)
6001 goto next;
6002
6003 if (key.offset > clone_root->offset) {
6004 /* Implicit hole, NO_HOLES feature enabled. */
6005 u64 hole_len = key.offset - clone_root->offset;
6006
6007 if (hole_len > len)
6008 hole_len = len;
6009 ret = send_extent_data(sctx, dst_path, offset,
6010 hole_len);
6011 if (ret < 0)
6012 goto out;
6013
6014 len -= hole_len;
6015 if (len == 0)
6016 break;
6017 offset += hole_len;
6018 clone_root->offset += hole_len;
6019 data_offset += hole_len;
6020 }
6021
6022 if (key.offset >= clone_root->offset + len)
6023 break;
6024
6025 if (key.offset >= clone_src_i_size)
6026 break;
6027
6028 if (key.offset + ext_len > clone_src_i_size) {
6029 ext_len = clone_src_i_size - key.offset;
6030 crossed_src_i_size = true;
6031 }
6032
6033 clone_data_offset = btrfs_file_extent_offset(leaf, ei);
6034 if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte) {
6035 clone_root->offset = key.offset;
6036 if (clone_data_offset < data_offset &&
6037 clone_data_offset + ext_len > data_offset) {
6038 u64 extent_offset;
6039
6040 extent_offset = data_offset - clone_data_offset;
6041 ext_len -= extent_offset;
6042 clone_data_offset += extent_offset;
6043 clone_root->offset += extent_offset;
6044 }
6045 }
6046
6047 clone_len = min_t(u64, ext_len, len);
6048
6049 if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte &&
6050 clone_data_offset == data_offset) {
6051 const u64 src_end = clone_root->offset + clone_len;
6052 const u64 sectorsize = SZ_64K;
6053
6054 /*
6055 * We can't clone the last block, when its size is not
6056 * sector size aligned, into the middle of a file. If we
6057 * do so, the receiver will get a failure (-EINVAL) when
6058 * trying to clone or will silently corrupt the data in
6059 * the destination file if it's on a kernel without the
6060 * fix introduced by commit ac765f83f1397646
6061 * ("Btrfs: fix data corruption due to cloning of eof
6062 * block).
6063 *
6064 * So issue a clone of the aligned down range plus a
6065 * regular write for the eof block, if we hit that case.
6066 *
6067 * Also, we use the maximum possible sector size, 64K,
6068 * because we don't know what's the sector size of the
6069 * filesystem that receives the stream, so we have to
6070 * assume the largest possible sector size.
6071 */
6072 if (src_end == clone_src_i_size &&
6073 !IS_ALIGNED(src_end, sectorsize) &&
6074 offset + clone_len < sctx->cur_inode_size) {
6075 u64 slen;
6076
6077 slen = ALIGN_DOWN(src_end - clone_root->offset,
6078 sectorsize);
6079 if (slen > 0) {
6080 ret = send_clone(sctx, offset, slen,
6081 clone_root);
6082 if (ret < 0)
6083 goto out;
6084 }
6085 ret = send_extent_data(sctx, dst_path,
6086 offset + slen,
6087 clone_len - slen);
6088 } else {
6089 ret = send_clone(sctx, offset, clone_len,
6090 clone_root);
6091 }
6092 } else if (crossed_src_i_size && clone_len < len) {
6093 /*
6094 * If we are at i_size of the clone source inode and we
6095 * can not clone from it, terminate the loop. This is
6096 * to avoid sending two write operations, one with a
6097 * length matching clone_len and the final one after
6098 * this loop with a length of len - clone_len.
6099 *
6100 * When using encoded writes (BTRFS_SEND_FLAG_COMPRESSED
6101 * was passed to the send ioctl), this helps avoid
6102 * sending an encoded write for an offset that is not
6103 * sector size aligned, in case the i_size of the source
6104 * inode is not sector size aligned. That will make the
6105 * receiver fallback to decompression of the data and
6106 * writing it using regular buffered IO, therefore while
6107 * not incorrect, it's not optimal due decompression and
6108 * possible re-compression at the receiver.
6109 */
6110 break;
6111 } else {
6112 ret = send_extent_data(sctx, dst_path, offset,
6113 clone_len);
6114 }
6115
6116 if (ret < 0)
6117 goto out;
6118
6119 len -= clone_len;
6120 if (len == 0)
6121 break;
6122 offset += clone_len;
6123 clone_root->offset += clone_len;
6124
6125 /*
6126 * If we are cloning from the file we are currently processing,
6127 * and using the send root as the clone root, we must stop once
6128 * the current clone offset reaches the current eof of the file
6129 * at the receiver, otherwise we would issue an invalid clone
6130 * operation (source range going beyond eof) and cause the
6131 * receiver to fail. So if we reach the current eof, bail out
6132 * and fallback to a regular write.
6133 */
6134 if (clone_root->root == sctx->send_root &&
6135 clone_root->ino == sctx->cur_ino &&
6136 clone_root->offset >= sctx->cur_inode_next_write_offset)
6137 break;
6138
6139 data_offset += clone_len;
6140 next:
6141 path->slots[0]++;
6142 }
6143
6144 if (len > 0)
6145 ret = send_extent_data(sctx, dst_path, offset, len);
6146 else
6147 ret = 0;
6148 out:
6149 btrfs_free_path(path);
6150 return ret;
6151 }
6152
6153 static int send_write_or_clone(struct send_ctx *sctx,
6154 struct btrfs_path *path,
6155 struct btrfs_key *key,
6156 struct clone_root *clone_root)
6157 {
6158 int ret = 0;
6159 u64 offset = key->offset;
6160 u64 end;
6161 u64 bs = sctx->send_root->fs_info->sectorsize;
6162 struct btrfs_file_extent_item *ei;
6163 u64 disk_byte;
6164 u64 data_offset;
6165 u64 num_bytes;
6166 struct btrfs_inode_info info = { 0 };
6167
6168 end = min_t(u64, btrfs_file_extent_end(path), sctx->cur_inode_size);
6169 if (offset >= end)
6170 return 0;
6171
6172 num_bytes = end - offset;
6173
6174 if (!clone_root)
6175 goto write_data;
6176
6177 if (IS_ALIGNED(end, bs))
6178 goto clone_data;
6179
6180 /*
6181 * If the extent end is not aligned, we can clone if the extent ends at
6182 * the i_size of the inode and the clone range ends at the i_size of the
6183 * source inode, otherwise the clone operation fails with -EINVAL.
6184 */
6185 if (end != sctx->cur_inode_size)
6186 goto write_data;
6187
6188 ret = get_inode_info(clone_root->root, clone_root->ino, &info);
6189 if (ret < 0)
6190 return ret;
6191
6192 if (clone_root->offset + num_bytes == info.size) {
6193 /*
6194 * The final size of our file matches the end offset, but it may
6195 * be that its current size is larger, so we have to truncate it
6196 * to any value between the start offset of the range and the
6197 * final i_size, otherwise the clone operation is invalid
6198 * because it's unaligned and it ends before the current EOF.
6199 * We do this truncate to the final i_size when we finish
6200 * processing the inode, but it's too late by then. And here we
6201 * truncate to the start offset of the range because it's always
6202 * sector size aligned while if it were the final i_size it
6203 * would result in dirtying part of a page, filling part of a
6204 * page with zeroes and then having the clone operation at the
6205 * receiver trigger IO and wait for it due to the dirty page.
6206 */
6207 if (sctx->parent_root != NULL) {
6208 ret = send_truncate(sctx, sctx->cur_ino,
6209 sctx->cur_inode_gen, offset);
6210 if (ret < 0)
6211 return ret;
6212 }
6213 goto clone_data;
6214 }
6215
6216 write_data:
6217 ret = send_extent_data(sctx, path, offset, num_bytes);
6218 sctx->cur_inode_next_write_offset = end;
6219 return ret;
6220
6221 clone_data:
6222 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
6223 struct btrfs_file_extent_item);
6224 disk_byte = btrfs_file_extent_disk_bytenr(path->nodes[0], ei);
6225 data_offset = btrfs_file_extent_offset(path->nodes[0], ei);
6226 ret = clone_range(sctx, path, clone_root, disk_byte, data_offset, offset,
6227 num_bytes);
6228 sctx->cur_inode_next_write_offset = end;
6229 return ret;
6230 }
6231
6232 static int is_extent_unchanged(struct send_ctx *sctx,
6233 struct btrfs_path *left_path,
6234 struct btrfs_key *ekey)
6235 {
6236 int ret = 0;
6237 struct btrfs_key key;
6238 struct btrfs_path *path = NULL;
6239 struct extent_buffer *eb;
6240 int slot;
6241 struct btrfs_key found_key;
6242 struct btrfs_file_extent_item *ei;
6243 u64 left_disknr;
6244 u64 right_disknr;
6245 u64 left_offset;
6246 u64 right_offset;
6247 u64 left_offset_fixed;
6248 u64 left_len;
6249 u64 right_len;
6250 u64 left_gen;
6251 u64 right_gen;
6252 u8 left_type;
6253 u8 right_type;
6254
6255 path = alloc_path_for_send();
6256 if (!path)
6257 return -ENOMEM;
6258
6259 eb = left_path->nodes[0];
6260 slot = left_path->slots[0];
6261 ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
6262 left_type = btrfs_file_extent_type(eb, ei);
6263
6264 if (left_type != BTRFS_FILE_EXTENT_REG) {
6265 ret = 0;
6266 goto out;
6267 }
6268 left_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
6269 left_len = btrfs_file_extent_num_bytes(eb, ei);
6270 left_offset = btrfs_file_extent_offset(eb, ei);
6271 left_gen = btrfs_file_extent_generation(eb, ei);
6272
6273 /*
6274 * Following comments will refer to these graphics. L is the left
6275 * extents which we are checking at the moment. 1-8 are the right
6276 * extents that we iterate.
6277 *
6278 * |-----L-----|
6279 * |-1-|-2a-|-3-|-4-|-5-|-6-|
6280 *
6281 * |-----L-----|
6282 * |--1--|-2b-|...(same as above)
6283 *
6284 * Alternative situation. Happens on files where extents got split.
6285 * |-----L-----|
6286 * |-----------7-----------|-6-|
6287 *
6288 * Alternative situation. Happens on files which got larger.
6289 * |-----L-----|
6290 * |-8-|
6291 * Nothing follows after 8.
6292 */
6293
6294 key.objectid = ekey->objectid;
6295 key.type = BTRFS_EXTENT_DATA_KEY;
6296 key.offset = ekey->offset;
6297 ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0);
6298 if (ret < 0)
6299 goto out;
6300 if (ret) {
6301 ret = 0;
6302 goto out;
6303 }
6304
6305 /*
6306 * Handle special case where the right side has no extents at all.
6307 */
6308 eb = path->nodes[0];
6309 slot = path->slots[0];
6310 btrfs_item_key_to_cpu(eb, &found_key, slot);
6311 if (found_key.objectid != key.objectid ||
6312 found_key.type != key.type) {
6313 /* If we're a hole then just pretend nothing changed */
6314 ret = (left_disknr) ? 0 : 1;
6315 goto out;
6316 }
6317
6318 /*
6319 * We're now on 2a, 2b or 7.
6320 */
6321 key = found_key;
6322 while (key.offset < ekey->offset + left_len) {
6323 ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
6324 right_type = btrfs_file_extent_type(eb, ei);
6325 if (right_type != BTRFS_FILE_EXTENT_REG &&
6326 right_type != BTRFS_FILE_EXTENT_INLINE) {
6327 ret = 0;
6328 goto out;
6329 }
6330
6331 if (right_type == BTRFS_FILE_EXTENT_INLINE) {
6332 right_len = btrfs_file_extent_ram_bytes(eb, ei);
6333 right_len = PAGE_ALIGN(right_len);
6334 } else {
6335 right_len = btrfs_file_extent_num_bytes(eb, ei);
6336 }
6337
6338 /*
6339 * Are we at extent 8? If yes, we know the extent is changed.
6340 * This may only happen on the first iteration.
6341 */
6342 if (found_key.offset + right_len <= ekey->offset) {
6343 /* If we're a hole just pretend nothing changed */
6344 ret = (left_disknr) ? 0 : 1;
6345 goto out;
6346 }
6347
6348 /*
6349 * We just wanted to see if when we have an inline extent, what
6350 * follows it is a regular extent (wanted to check the above
6351 * condition for inline extents too). This should normally not
6352 * happen but it's possible for example when we have an inline
6353 * compressed extent representing data with a size matching
6354 * the page size (currently the same as sector size).
6355 */
6356 if (right_type == BTRFS_FILE_EXTENT_INLINE) {
6357 ret = 0;
6358 goto out;
6359 }
6360
6361 right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
6362 right_offset = btrfs_file_extent_offset(eb, ei);
6363 right_gen = btrfs_file_extent_generation(eb, ei);
6364
6365 left_offset_fixed = left_offset;
6366 if (key.offset < ekey->offset) {
6367 /* Fix the right offset for 2a and 7. */
6368 right_offset += ekey->offset - key.offset;
6369 } else {
6370 /* Fix the left offset for all behind 2a and 2b */
6371 left_offset_fixed += key.offset - ekey->offset;
6372 }
6373
6374 /*
6375 * Check if we have the same extent.
6376 */
6377 if (left_disknr != right_disknr ||
6378 left_offset_fixed != right_offset ||
6379 left_gen != right_gen) {
6380 ret = 0;
6381 goto out;
6382 }
6383
6384 /*
6385 * Go to the next extent.
6386 */
6387 ret = btrfs_next_item(sctx->parent_root, path);
6388 if (ret < 0)
6389 goto out;
6390 if (!ret) {
6391 eb = path->nodes[0];
6392 slot = path->slots[0];
6393 btrfs_item_key_to_cpu(eb, &found_key, slot);
6394 }
6395 if (ret || found_key.objectid != key.objectid ||
6396 found_key.type != key.type) {
6397 key.offset += right_len;
6398 break;
6399 }
6400 if (found_key.offset != key.offset + right_len) {
6401 ret = 0;
6402 goto out;
6403 }
6404 key = found_key;
6405 }
6406
6407 /*
6408 * We're now behind the left extent (treat as unchanged) or at the end
6409 * of the right side (treat as changed).
6410 */
6411 if (key.offset >= ekey->offset + left_len)
6412 ret = 1;
6413 else
6414 ret = 0;
6415
6416
6417 out:
6418 btrfs_free_path(path);
6419 return ret;
6420 }
6421
6422 static int get_last_extent(struct send_ctx *sctx, u64 offset)
6423 {
6424 struct btrfs_path *path;
6425 struct btrfs_root *root = sctx->send_root;
6426 struct btrfs_key key;
6427 int ret;
6428
6429 path = alloc_path_for_send();
6430 if (!path)
6431 return -ENOMEM;
6432
6433 sctx->cur_inode_last_extent = 0;
6434
6435 key.objectid = sctx->cur_ino;
6436 key.type = BTRFS_EXTENT_DATA_KEY;
6437 key.offset = offset;
6438 ret = btrfs_search_slot_for_read(root, &key, path, 0, 1);
6439 if (ret < 0)
6440 goto out;
6441 ret = 0;
6442 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
6443 if (key.objectid != sctx->cur_ino || key.type != BTRFS_EXTENT_DATA_KEY)
6444 goto out;
6445
6446 sctx->cur_inode_last_extent = btrfs_file_extent_end(path);
6447 out:
6448 btrfs_free_path(path);
6449 return ret;
6450 }
6451
6452 static int range_is_hole_in_parent(struct send_ctx *sctx,
6453 const u64 start,
6454 const u64 end)
6455 {
6456 struct btrfs_path *path;
6457 struct btrfs_key key;
6458 struct btrfs_root *root = sctx->parent_root;
6459 u64 search_start = start;
6460 int ret;
6461
6462 path = alloc_path_for_send();
6463 if (!path)
6464 return -ENOMEM;
6465
6466 key.objectid = sctx->cur_ino;
6467 key.type = BTRFS_EXTENT_DATA_KEY;
6468 key.offset = search_start;
6469 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6470 if (ret < 0)
6471 goto out;
6472 if (ret > 0 && path->slots[0] > 0)
6473 path->slots[0]--;
6474
6475 while (search_start < end) {
6476 struct extent_buffer *leaf = path->nodes[0];
6477 int slot = path->slots[0];
6478 struct btrfs_file_extent_item *fi;
6479 u64 extent_end;
6480
6481 if (slot >= btrfs_header_nritems(leaf)) {
6482 ret = btrfs_next_leaf(root, path);
6483 if (ret < 0)
6484 goto out;
6485 else if (ret > 0)
6486 break;
6487 continue;
6488 }
6489
6490 btrfs_item_key_to_cpu(leaf, &key, slot);
6491 if (key.objectid < sctx->cur_ino ||
6492 key.type < BTRFS_EXTENT_DATA_KEY)
6493 goto next;
6494 if (key.objectid > sctx->cur_ino ||
6495 key.type > BTRFS_EXTENT_DATA_KEY ||
6496 key.offset >= end)
6497 break;
6498
6499 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6500 extent_end = btrfs_file_extent_end(path);
6501 if (extent_end <= start)
6502 goto next;
6503 if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) {
6504 search_start = extent_end;
6505 goto next;
6506 }
6507 ret = 0;
6508 goto out;
6509 next:
6510 path->slots[0]++;
6511 }
6512 ret = 1;
6513 out:
6514 btrfs_free_path(path);
6515 return ret;
6516 }
6517
6518 static int maybe_send_hole(struct send_ctx *sctx, struct btrfs_path *path,
6519 struct btrfs_key *key)
6520 {
6521 int ret = 0;
6522
6523 if (sctx->cur_ino != key->objectid || !need_send_hole(sctx))
6524 return 0;
6525
6526 /*
6527 * Get last extent's end offset (exclusive) if we haven't determined it
6528 * yet (we're processing the first file extent item that is new), or if
6529 * we're at the first slot of a leaf and the last extent's end is less
6530 * than the current extent's offset, because we might have skipped
6531 * entire leaves that contained only file extent items for our current
6532 * inode. These leaves have a generation number smaller (older) than the
6533 * one in the current leaf and the leaf our last extent came from, and
6534 * are located between these 2 leaves.
6535 */
6536 if ((sctx->cur_inode_last_extent == (u64)-1) ||
6537 (path->slots[0] == 0 && sctx->cur_inode_last_extent < key->offset)) {
6538 ret = get_last_extent(sctx, key->offset - 1);
6539 if (ret)
6540 return ret;
6541 }
6542
6543 if (sctx->cur_inode_last_extent < key->offset) {
6544 ret = range_is_hole_in_parent(sctx,
6545 sctx->cur_inode_last_extent,
6546 key->offset);
6547 if (ret < 0)
6548 return ret;
6549 else if (ret == 0)
6550 ret = send_hole(sctx, key->offset);
6551 else
6552 ret = 0;
6553 }
6554 sctx->cur_inode_last_extent = btrfs_file_extent_end(path);
6555 return ret;
6556 }
6557
6558 static int process_extent(struct send_ctx *sctx,
6559 struct btrfs_path *path,
6560 struct btrfs_key *key)
6561 {
6562 struct clone_root *found_clone = NULL;
6563 int ret = 0;
6564
6565 if (S_ISLNK(sctx->cur_inode_mode))
6566 return 0;
6567
6568 if (sctx->parent_root && !sctx->cur_inode_new) {
6569 ret = is_extent_unchanged(sctx, path, key);
6570 if (ret < 0)
6571 goto out;
6572 if (ret) {
6573 ret = 0;
6574 goto out_hole;
6575 }
6576 } else {
6577 struct btrfs_file_extent_item *ei;
6578 u8 type;
6579
6580 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
6581 struct btrfs_file_extent_item);
6582 type = btrfs_file_extent_type(path->nodes[0], ei);
6583 if (type == BTRFS_FILE_EXTENT_PREALLOC ||
6584 type == BTRFS_FILE_EXTENT_REG) {
6585 /*
6586 * The send spec does not have a prealloc command yet,
6587 * so just leave a hole for prealloc'ed extents until
6588 * we have enough commands queued up to justify rev'ing
6589 * the send spec.
6590 */
6591 if (type == BTRFS_FILE_EXTENT_PREALLOC) {
6592 ret = 0;
6593 goto out;
6594 }
6595
6596 /* Have a hole, just skip it. */
6597 if (btrfs_file_extent_disk_bytenr(path->nodes[0], ei) == 0) {
6598 ret = 0;
6599 goto out;
6600 }
6601 }
6602 }
6603
6604 ret = find_extent_clone(sctx, path, key->objectid, key->offset,
6605 sctx->cur_inode_size, &found_clone);
6606 if (ret != -ENOENT && ret < 0)
6607 goto out;
6608
6609 ret = send_write_or_clone(sctx, path, key, found_clone);
6610 if (ret)
6611 goto out;
6612 out_hole:
6613 ret = maybe_send_hole(sctx, path, key);
6614 out:
6615 return ret;
6616 }
6617
6618 static int process_all_extents(struct send_ctx *sctx)
6619 {
6620 int ret = 0;
6621 int iter_ret = 0;
6622 struct btrfs_root *root;
6623 struct btrfs_path *path;
6624 struct btrfs_key key;
6625 struct btrfs_key found_key;
6626
6627 root = sctx->send_root;
6628 path = alloc_path_for_send();
6629 if (!path)
6630 return -ENOMEM;
6631
6632 key.objectid = sctx->cmp_key->objectid;
6633 key.type = BTRFS_EXTENT_DATA_KEY;
6634 key.offset = 0;
6635 btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
6636 if (found_key.objectid != key.objectid ||
6637 found_key.type != key.type) {
6638 ret = 0;
6639 break;
6640 }
6641
6642 ret = process_extent(sctx, path, &found_key);
6643 if (ret < 0)
6644 break;
6645 }
6646 /* Catch error found during iteration */
6647 if (iter_ret < 0)
6648 ret = iter_ret;
6649
6650 btrfs_free_path(path);
6651 return ret;
6652 }
6653
6654 static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end,
6655 int *pending_move,
6656 int *refs_processed)
6657 {
6658 int ret = 0;
6659
6660 if (sctx->cur_ino == 0)
6661 goto out;
6662 if (!at_end && sctx->cur_ino == sctx->cmp_key->objectid &&
6663 sctx->cmp_key->type <= BTRFS_INODE_EXTREF_KEY)
6664 goto out;
6665 if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs))
6666 goto out;
6667
6668 ret = process_recorded_refs(sctx, pending_move);
6669 if (ret < 0)
6670 goto out;
6671
6672 *refs_processed = 1;
6673 out:
6674 return ret;
6675 }
6676
6677 static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
6678 {
6679 int ret = 0;
6680 struct btrfs_inode_info info;
6681 u64 left_mode;
6682 u64 left_uid;
6683 u64 left_gid;
6684 u64 left_fileattr;
6685 u64 right_mode;
6686 u64 right_uid;
6687 u64 right_gid;
6688 u64 right_fileattr;
6689 int need_chmod = 0;
6690 int need_chown = 0;
6691 bool need_fileattr = false;
6692 int need_truncate = 1;
6693 int pending_move = 0;
6694 int refs_processed = 0;
6695
6696 if (sctx->ignore_cur_inode)
6697 return 0;
6698
6699 ret = process_recorded_refs_if_needed(sctx, at_end, &pending_move,
6700 &refs_processed);
6701 if (ret < 0)
6702 goto out;
6703
6704 /*
6705 * We have processed the refs and thus need to advance send_progress.
6706 * Now, calls to get_cur_xxx will take the updated refs of the current
6707 * inode into account.
6708 *
6709 * On the other hand, if our current inode is a directory and couldn't
6710 * be moved/renamed because its parent was renamed/moved too and it has
6711 * a higher inode number, we can only move/rename our current inode
6712 * after we moved/renamed its parent. Therefore in this case operate on
6713 * the old path (pre move/rename) of our current inode, and the
6714 * move/rename will be performed later.
6715 */
6716 if (refs_processed && !pending_move)
6717 sctx->send_progress = sctx->cur_ino + 1;
6718
6719 if (sctx->cur_ino == 0 || sctx->cur_inode_deleted)
6720 goto out;
6721 if (!at_end && sctx->cmp_key->objectid == sctx->cur_ino)
6722 goto out;
6723 ret = get_inode_info(sctx->send_root, sctx->cur_ino, &info);
6724 if (ret < 0)
6725 goto out;
6726 left_mode = info.mode;
6727 left_uid = info.uid;
6728 left_gid = info.gid;
6729 left_fileattr = info.fileattr;
6730
6731 if (!sctx->parent_root || sctx->cur_inode_new) {
6732 need_chown = 1;
6733 if (!S_ISLNK(sctx->cur_inode_mode))
6734 need_chmod = 1;
6735 if (sctx->cur_inode_next_write_offset == sctx->cur_inode_size)
6736 need_truncate = 0;
6737 } else {
6738 u64 old_size;
6739
6740 ret = get_inode_info(sctx->parent_root, sctx->cur_ino, &info);
6741 if (ret < 0)
6742 goto out;
6743 old_size = info.size;
6744 right_mode = info.mode;
6745 right_uid = info.uid;
6746 right_gid = info.gid;
6747 right_fileattr = info.fileattr;
6748
6749 if (left_uid != right_uid || left_gid != right_gid)
6750 need_chown = 1;
6751 if (!S_ISLNK(sctx->cur_inode_mode) && left_mode != right_mode)
6752 need_chmod = 1;
6753 if (!S_ISLNK(sctx->cur_inode_mode) && left_fileattr != right_fileattr)
6754 need_fileattr = true;
6755 if ((old_size == sctx->cur_inode_size) ||
6756 (sctx->cur_inode_size > old_size &&
6757 sctx->cur_inode_next_write_offset == sctx->cur_inode_size))
6758 need_truncate = 0;
6759 }
6760
6761 if (S_ISREG(sctx->cur_inode_mode)) {
6762 if (need_send_hole(sctx)) {
6763 if (sctx->cur_inode_last_extent == (u64)-1 ||
6764 sctx->cur_inode_last_extent <
6765 sctx->cur_inode_size) {
6766 ret = get_last_extent(sctx, (u64)-1);
6767 if (ret)
6768 goto out;
6769 }
6770 if (sctx->cur_inode_last_extent < sctx->cur_inode_size) {
6771 ret = range_is_hole_in_parent(sctx,
6772 sctx->cur_inode_last_extent,
6773 sctx->cur_inode_size);
6774 if (ret < 0) {
6775 goto out;
6776 } else if (ret == 0) {
6777 ret = send_hole(sctx, sctx->cur_inode_size);
6778 if (ret < 0)
6779 goto out;
6780 } else {
6781 /* Range is already a hole, skip. */
6782 ret = 0;
6783 }
6784 }
6785 }
6786 if (need_truncate) {
6787 ret = send_truncate(sctx, sctx->cur_ino,
6788 sctx->cur_inode_gen,
6789 sctx->cur_inode_size);
6790 if (ret < 0)
6791 goto out;
6792 }
6793 }
6794
6795 if (need_chown) {
6796 ret = send_chown(sctx, sctx->cur_ino, sctx->cur_inode_gen,
6797 left_uid, left_gid);
6798 if (ret < 0)
6799 goto out;
6800 }
6801 if (need_chmod) {
6802 ret = send_chmod(sctx, sctx->cur_ino, sctx->cur_inode_gen,
6803 left_mode);
6804 if (ret < 0)
6805 goto out;
6806 }
6807 if (need_fileattr) {
6808 ret = send_fileattr(sctx, sctx->cur_ino, sctx->cur_inode_gen,
6809 left_fileattr);
6810 if (ret < 0)
6811 goto out;
6812 }
6813
6814 if (proto_cmd_ok(sctx, BTRFS_SEND_C_ENABLE_VERITY)
6815 && sctx->cur_inode_needs_verity) {
6816 ret = process_verity(sctx);
6817 if (ret < 0)
6818 goto out;
6819 }
6820
6821 ret = send_capabilities(sctx);
6822 if (ret < 0)
6823 goto out;
6824
6825 /*
6826 * If other directory inodes depended on our current directory
6827 * inode's move/rename, now do their move/rename operations.
6828 */
6829 if (!is_waiting_for_move(sctx, sctx->cur_ino)) {
6830 ret = apply_children_dir_moves(sctx);
6831 if (ret)
6832 goto out;
6833 /*
6834 * Need to send that every time, no matter if it actually
6835 * changed between the two trees as we have done changes to
6836 * the inode before. If our inode is a directory and it's
6837 * waiting to be moved/renamed, we will send its utimes when
6838 * it's moved/renamed, therefore we don't need to do it here.
6839 */
6840 sctx->send_progress = sctx->cur_ino + 1;
6841
6842 /*
6843 * If the current inode is a non-empty directory, delay issuing
6844 * the utimes command for it, as it's very likely we have inodes
6845 * with an higher number inside it. We want to issue the utimes
6846 * command only after adding all dentries to it.
6847 */
6848 if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_size > 0)
6849 ret = cache_dir_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen);
6850 else
6851 ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen);
6852
6853 if (ret < 0)
6854 goto out;
6855 }
6856
6857 out:
6858 if (!ret)
6859 ret = trim_dir_utimes_cache(sctx);
6860
6861 return ret;
6862 }
6863
6864 static void close_current_inode(struct send_ctx *sctx)
6865 {
6866 u64 i_size;
6867
6868 if (sctx->cur_inode == NULL)
6869 return;
6870
6871 i_size = i_size_read(sctx->cur_inode);
6872
6873 /*
6874 * If we are doing an incremental send, we may have extents between the
6875 * last processed extent and the i_size that have not been processed
6876 * because they haven't changed but we may have read some of their pages
6877 * through readahead, see the comments at send_extent_data().
6878 */
6879 if (sctx->clean_page_cache && sctx->page_cache_clear_start < i_size)
6880 truncate_inode_pages_range(&sctx->cur_inode->i_data,
6881 sctx->page_cache_clear_start,
6882 round_up(i_size, PAGE_SIZE) - 1);
6883
6884 iput(sctx->cur_inode);
6885 sctx->cur_inode = NULL;
6886 }
6887
6888 static int changed_inode(struct send_ctx *sctx,
6889 enum btrfs_compare_tree_result result)
6890 {
6891 int ret = 0;
6892 struct btrfs_key *key = sctx->cmp_key;
6893 struct btrfs_inode_item *left_ii = NULL;
6894 struct btrfs_inode_item *right_ii = NULL;
6895 u64 left_gen = 0;
6896 u64 right_gen = 0;
6897
6898 close_current_inode(sctx);
6899
6900 sctx->cur_ino = key->objectid;
6901 sctx->cur_inode_new_gen = false;
6902 sctx->cur_inode_last_extent = (u64)-1;
6903 sctx->cur_inode_next_write_offset = 0;
6904 sctx->ignore_cur_inode = false;
6905
6906 /*
6907 * Set send_progress to current inode. This will tell all get_cur_xxx
6908 * functions that the current inode's refs are not updated yet. Later,
6909 * when process_recorded_refs is finished, it is set to cur_ino + 1.
6910 */
6911 sctx->send_progress = sctx->cur_ino;
6912
6913 if (result == BTRFS_COMPARE_TREE_NEW ||
6914 result == BTRFS_COMPARE_TREE_CHANGED) {
6915 left_ii = btrfs_item_ptr(sctx->left_path->nodes[0],
6916 sctx->left_path->slots[0],
6917 struct btrfs_inode_item);
6918 left_gen = btrfs_inode_generation(sctx->left_path->nodes[0],
6919 left_ii);
6920 } else {
6921 right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
6922 sctx->right_path->slots[0],
6923 struct btrfs_inode_item);
6924 right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
6925 right_ii);
6926 }
6927 if (result == BTRFS_COMPARE_TREE_CHANGED) {
6928 right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
6929 sctx->right_path->slots[0],
6930 struct btrfs_inode_item);
6931
6932 right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
6933 right_ii);
6934
6935 /*
6936 * The cur_ino = root dir case is special here. We can't treat
6937 * the inode as deleted+reused because it would generate a
6938 * stream that tries to delete/mkdir the root dir.
6939 */
6940 if (left_gen != right_gen &&
6941 sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
6942 sctx->cur_inode_new_gen = true;
6943 }
6944
6945 /*
6946 * Normally we do not find inodes with a link count of zero (orphans)
6947 * because the most common case is to create a snapshot and use it
6948 * for a send operation. However other less common use cases involve
6949 * using a subvolume and send it after turning it to RO mode just
6950 * after deleting all hard links of a file while holding an open
6951 * file descriptor against it or turning a RO snapshot into RW mode,
6952 * keep an open file descriptor against a file, delete it and then
6953 * turn the snapshot back to RO mode before using it for a send
6954 * operation. The former is what the receiver operation does.
6955 * Therefore, if we want to send these snapshots soon after they're
6956 * received, we need to handle orphan inodes as well. Moreover, orphans
6957 * can appear not only in the send snapshot but also in the parent
6958 * snapshot. Here are several cases:
6959 *
6960 * Case 1: BTRFS_COMPARE_TREE_NEW
6961 * | send snapshot | action
6962 * --------------------------------
6963 * nlink | 0 | ignore
6964 *
6965 * Case 2: BTRFS_COMPARE_TREE_DELETED
6966 * | parent snapshot | action
6967 * ----------------------------------
6968 * nlink | 0 | as usual
6969 * Note: No unlinks will be sent because there're no paths for it.
6970 *
6971 * Case 3: BTRFS_COMPARE_TREE_CHANGED
6972 * | | parent snapshot | send snapshot | action
6973 * -----------------------------------------------------------------------
6974 * subcase 1 | nlink | 0 | 0 | ignore
6975 * subcase 2 | nlink | >0 | 0 | new_gen(deletion)
6976 * subcase 3 | nlink | 0 | >0 | new_gen(creation)
6977 *
6978 */
6979 if (result == BTRFS_COMPARE_TREE_NEW) {
6980 if (btrfs_inode_nlink(sctx->left_path->nodes[0], left_ii) == 0) {
6981 sctx->ignore_cur_inode = true;
6982 goto out;
6983 }
6984 sctx->cur_inode_gen = left_gen;
6985 sctx->cur_inode_new = true;
6986 sctx->cur_inode_deleted = false;
6987 sctx->cur_inode_size = btrfs_inode_size(
6988 sctx->left_path->nodes[0], left_ii);
6989 sctx->cur_inode_mode = btrfs_inode_mode(
6990 sctx->left_path->nodes[0], left_ii);
6991 sctx->cur_inode_rdev = btrfs_inode_rdev(
6992 sctx->left_path->nodes[0], left_ii);
6993 if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
6994 ret = send_create_inode_if_needed(sctx);
6995 } else if (result == BTRFS_COMPARE_TREE_DELETED) {
6996 sctx->cur_inode_gen = right_gen;
6997 sctx->cur_inode_new = false;
6998 sctx->cur_inode_deleted = true;
6999 sctx->cur_inode_size = btrfs_inode_size(
7000 sctx->right_path->nodes[0], right_ii);
7001 sctx->cur_inode_mode = btrfs_inode_mode(
7002 sctx->right_path->nodes[0], right_ii);
7003 } else if (result == BTRFS_COMPARE_TREE_CHANGED) {
7004 u32 new_nlinks, old_nlinks;
7005
7006 new_nlinks = btrfs_inode_nlink(sctx->left_path->nodes[0], left_ii);
7007 old_nlinks = btrfs_inode_nlink(sctx->right_path->nodes[0], right_ii);
7008 if (new_nlinks == 0 && old_nlinks == 0) {
7009 sctx->ignore_cur_inode = true;
7010 goto out;
7011 } else if (new_nlinks == 0 || old_nlinks == 0) {
7012 sctx->cur_inode_new_gen = 1;
7013 }
7014 /*
7015 * We need to do some special handling in case the inode was
7016 * reported as changed with a changed generation number. This
7017 * means that the original inode was deleted and new inode
7018 * reused the same inum. So we have to treat the old inode as
7019 * deleted and the new one as new.
7020 */
7021 if (sctx->cur_inode_new_gen) {
7022 /*
7023 * First, process the inode as if it was deleted.
7024 */
7025 if (old_nlinks > 0) {
7026 sctx->cur_inode_gen = right_gen;
7027 sctx->cur_inode_new = false;
7028 sctx->cur_inode_deleted = true;
7029 sctx->cur_inode_size = btrfs_inode_size(
7030 sctx->right_path->nodes[0], right_ii);
7031 sctx->cur_inode_mode = btrfs_inode_mode(
7032 sctx->right_path->nodes[0], right_ii);
7033 ret = process_all_refs(sctx,
7034 BTRFS_COMPARE_TREE_DELETED);
7035 if (ret < 0)
7036 goto out;
7037 }
7038
7039 /*
7040 * Now process the inode as if it was new.
7041 */
7042 if (new_nlinks > 0) {
7043 sctx->cur_inode_gen = left_gen;
7044 sctx->cur_inode_new = true;
7045 sctx->cur_inode_deleted = false;
7046 sctx->cur_inode_size = btrfs_inode_size(
7047 sctx->left_path->nodes[0],
7048 left_ii);
7049 sctx->cur_inode_mode = btrfs_inode_mode(
7050 sctx->left_path->nodes[0],
7051 left_ii);
7052 sctx->cur_inode_rdev = btrfs_inode_rdev(
7053 sctx->left_path->nodes[0],
7054 left_ii);
7055 ret = send_create_inode_if_needed(sctx);
7056 if (ret < 0)
7057 goto out;
7058
7059 ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW);
7060 if (ret < 0)
7061 goto out;
7062 /*
7063 * Advance send_progress now as we did not get
7064 * into process_recorded_refs_if_needed in the
7065 * new_gen case.
7066 */
7067 sctx->send_progress = sctx->cur_ino + 1;
7068
7069 /*
7070 * Now process all extents and xattrs of the
7071 * inode as if they were all new.
7072 */
7073 ret = process_all_extents(sctx);
7074 if (ret < 0)
7075 goto out;
7076 ret = process_all_new_xattrs(sctx);
7077 if (ret < 0)
7078 goto out;
7079 }
7080 } else {
7081 sctx->cur_inode_gen = left_gen;
7082 sctx->cur_inode_new = false;
7083 sctx->cur_inode_new_gen = false;
7084 sctx->cur_inode_deleted = false;
7085 sctx->cur_inode_size = btrfs_inode_size(
7086 sctx->left_path->nodes[0], left_ii);
7087 sctx->cur_inode_mode = btrfs_inode_mode(
7088 sctx->left_path->nodes[0], left_ii);
7089 }
7090 }
7091
7092 out:
7093 return ret;
7094 }
7095
7096 /*
7097 * We have to process new refs before deleted refs, but compare_trees gives us
7098 * the new and deleted refs mixed. To fix this, we record the new/deleted refs
7099 * first and later process them in process_recorded_refs.
7100 * For the cur_inode_new_gen case, we skip recording completely because
7101 * changed_inode did already initiate processing of refs. The reason for this is
7102 * that in this case, compare_tree actually compares the refs of 2 different
7103 * inodes. To fix this, process_all_refs is used in changed_inode to handle all
7104 * refs of the right tree as deleted and all refs of the left tree as new.
7105 */
7106 static int changed_ref(struct send_ctx *sctx,
7107 enum btrfs_compare_tree_result result)
7108 {
7109 int ret = 0;
7110
7111 if (sctx->cur_ino != sctx->cmp_key->objectid) {
7112 inconsistent_snapshot_error(sctx, result, "reference");
7113 return -EIO;
7114 }
7115
7116 if (!sctx->cur_inode_new_gen &&
7117 sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) {
7118 if (result == BTRFS_COMPARE_TREE_NEW)
7119 ret = record_new_ref(sctx);
7120 else if (result == BTRFS_COMPARE_TREE_DELETED)
7121 ret = record_deleted_ref(sctx);
7122 else if (result == BTRFS_COMPARE_TREE_CHANGED)
7123 ret = record_changed_ref(sctx);
7124 }
7125
7126 return ret;
7127 }
7128
7129 /*
7130 * Process new/deleted/changed xattrs. We skip processing in the
7131 * cur_inode_new_gen case because changed_inode did already initiate processing
7132 * of xattrs. The reason is the same as in changed_ref
7133 */
7134 static int changed_xattr(struct send_ctx *sctx,
7135 enum btrfs_compare_tree_result result)
7136 {
7137 int ret = 0;
7138
7139 if (sctx->cur_ino != sctx->cmp_key->objectid) {
7140 inconsistent_snapshot_error(sctx, result, "xattr");
7141 return -EIO;
7142 }
7143
7144 if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
7145 if (result == BTRFS_COMPARE_TREE_NEW)
7146 ret = process_new_xattr(sctx);
7147 else if (result == BTRFS_COMPARE_TREE_DELETED)
7148 ret = process_deleted_xattr(sctx);
7149 else if (result == BTRFS_COMPARE_TREE_CHANGED)
7150 ret = process_changed_xattr(sctx);
7151 }
7152
7153 return ret;
7154 }
7155
7156 /*
7157 * Process new/deleted/changed extents. We skip processing in the
7158 * cur_inode_new_gen case because changed_inode did already initiate processing
7159 * of extents. The reason is the same as in changed_ref
7160 */
7161 static int changed_extent(struct send_ctx *sctx,
7162 enum btrfs_compare_tree_result result)
7163 {
7164 int ret = 0;
7165
7166 /*
7167 * We have found an extent item that changed without the inode item
7168 * having changed. This can happen either after relocation (where the
7169 * disk_bytenr of an extent item is replaced at
7170 * relocation.c:replace_file_extents()) or after deduplication into a
7171 * file in both the parent and send snapshots (where an extent item can
7172 * get modified or replaced with a new one). Note that deduplication
7173 * updates the inode item, but it only changes the iversion (sequence
7174 * field in the inode item) of the inode, so if a file is deduplicated
7175 * the same amount of times in both the parent and send snapshots, its
7176 * iversion becomes the same in both snapshots, whence the inode item is
7177 * the same on both snapshots.
7178 */
7179 if (sctx->cur_ino != sctx->cmp_key->objectid)
7180 return 0;
7181
7182 if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
7183 if (result != BTRFS_COMPARE_TREE_DELETED)
7184 ret = process_extent(sctx, sctx->left_path,
7185 sctx->cmp_key);
7186 }
7187
7188 return ret;
7189 }
7190
7191 static int changed_verity(struct send_ctx *sctx, enum btrfs_compare_tree_result result)
7192 {
7193 int ret = 0;
7194
7195 if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
7196 if (result == BTRFS_COMPARE_TREE_NEW)
7197 sctx->cur_inode_needs_verity = true;
7198 }
7199 return ret;
7200 }
7201
7202 static int dir_changed(struct send_ctx *sctx, u64 dir)
7203 {
7204 u64 orig_gen, new_gen;
7205 int ret;
7206
7207 ret = get_inode_gen(sctx->send_root, dir, &new_gen);
7208 if (ret)
7209 return ret;
7210
7211 ret = get_inode_gen(sctx->parent_root, dir, &orig_gen);
7212 if (ret)
7213 return ret;
7214
7215 return (orig_gen != new_gen) ? 1 : 0;
7216 }
7217
7218 static int compare_refs(struct send_ctx *sctx, struct btrfs_path *path,
7219 struct btrfs_key *key)
7220 {
7221 struct btrfs_inode_extref *extref;
7222 struct extent_buffer *leaf;
7223 u64 dirid = 0, last_dirid = 0;
7224 unsigned long ptr;
7225 u32 item_size;
7226 u32 cur_offset = 0;
7227 int ref_name_len;
7228 int ret = 0;
7229
7230 /* Easy case, just check this one dirid */
7231 if (key->type == BTRFS_INODE_REF_KEY) {
7232 dirid = key->offset;
7233
7234 ret = dir_changed(sctx, dirid);
7235 goto out;
7236 }
7237
7238 leaf = path->nodes[0];
7239 item_size = btrfs_item_size(leaf, path->slots[0]);
7240 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
7241 while (cur_offset < item_size) {
7242 extref = (struct btrfs_inode_extref *)(ptr +
7243 cur_offset);
7244 dirid = btrfs_inode_extref_parent(leaf, extref);
7245 ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
7246 cur_offset += ref_name_len + sizeof(*extref);
7247 if (dirid == last_dirid)
7248 continue;
7249 ret = dir_changed(sctx, dirid);
7250 if (ret)
7251 break;
7252 last_dirid = dirid;
7253 }
7254 out:
7255 return ret;
7256 }
7257
7258 /*
7259 * Updates compare related fields in sctx and simply forwards to the actual
7260 * changed_xxx functions.
7261 */
7262 static int changed_cb(struct btrfs_path *left_path,
7263 struct btrfs_path *right_path,
7264 struct btrfs_key *key,
7265 enum btrfs_compare_tree_result result,
7266 struct send_ctx *sctx)
7267 {
7268 int ret = 0;
7269
7270 /*
7271 * We can not hold the commit root semaphore here. This is because in
7272 * the case of sending and receiving to the same filesystem, using a
7273 * pipe, could result in a deadlock:
7274 *
7275 * 1) The task running send blocks on the pipe because it's full;
7276 *
7277 * 2) The task running receive, which is the only consumer of the pipe,
7278 * is waiting for a transaction commit (for example due to a space
7279 * reservation when doing a write or triggering a transaction commit
7280 * when creating a subvolume);
7281 *
7282 * 3) The transaction is waiting to write lock the commit root semaphore,
7283 * but can not acquire it since it's being held at 1).
7284 *
7285 * Down this call chain we write to the pipe through kernel_write().
7286 * The same type of problem can also happen when sending to a file that
7287 * is stored in the same filesystem - when reserving space for a write
7288 * into the file, we can trigger a transaction commit.
7289 *
7290 * Our caller has supplied us with clones of leaves from the send and
7291 * parent roots, so we're safe here from a concurrent relocation and
7292 * further reallocation of metadata extents while we are here. Below we
7293 * also assert that the leaves are clones.
7294 */
7295 lockdep_assert_not_held(&sctx->send_root->fs_info->commit_root_sem);
7296
7297 /*
7298 * We always have a send root, so left_path is never NULL. We will not
7299 * have a leaf when we have reached the end of the send root but have
7300 * not yet reached the end of the parent root.
7301 */
7302 if (left_path->nodes[0])
7303 ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED,
7304 &left_path->nodes[0]->bflags));
7305 /*
7306 * When doing a full send we don't have a parent root, so right_path is
7307 * NULL. When doing an incremental send, we may have reached the end of
7308 * the parent root already, so we don't have a leaf at right_path.
7309 */
7310 if (right_path && right_path->nodes[0])
7311 ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED,
7312 &right_path->nodes[0]->bflags));
7313
7314 if (result == BTRFS_COMPARE_TREE_SAME) {
7315 if (key->type == BTRFS_INODE_REF_KEY ||
7316 key->type == BTRFS_INODE_EXTREF_KEY) {
7317 ret = compare_refs(sctx, left_path, key);
7318 if (!ret)
7319 return 0;
7320 if (ret < 0)
7321 return ret;
7322 } else if (key->type == BTRFS_EXTENT_DATA_KEY) {
7323 return maybe_send_hole(sctx, left_path, key);
7324 } else {
7325 return 0;
7326 }
7327 result = BTRFS_COMPARE_TREE_CHANGED;
7328 ret = 0;
7329 }
7330
7331 sctx->left_path = left_path;
7332 sctx->right_path = right_path;
7333 sctx->cmp_key = key;
7334
7335 ret = finish_inode_if_needed(sctx, 0);
7336 if (ret < 0)
7337 goto out;
7338
7339 /* Ignore non-FS objects */
7340 if (key->objectid == BTRFS_FREE_INO_OBJECTID ||
7341 key->objectid == BTRFS_FREE_SPACE_OBJECTID)
7342 goto out;
7343
7344 if (key->type == BTRFS_INODE_ITEM_KEY) {
7345 ret = changed_inode(sctx, result);
7346 } else if (!sctx->ignore_cur_inode) {
7347 if (key->type == BTRFS_INODE_REF_KEY ||
7348 key->type == BTRFS_INODE_EXTREF_KEY)
7349 ret = changed_ref(sctx, result);
7350 else if (key->type == BTRFS_XATTR_ITEM_KEY)
7351 ret = changed_xattr(sctx, result);
7352 else if (key->type == BTRFS_EXTENT_DATA_KEY)
7353 ret = changed_extent(sctx, result);
7354 else if (key->type == BTRFS_VERITY_DESC_ITEM_KEY &&
7355 key->offset == 0)
7356 ret = changed_verity(sctx, result);
7357 }
7358
7359 out:
7360 return ret;
7361 }
7362
7363 static int search_key_again(const struct send_ctx *sctx,
7364 struct btrfs_root *root,
7365 struct btrfs_path *path,
7366 const struct btrfs_key *key)
7367 {
7368 int ret;
7369
7370 if (!path->need_commit_sem)
7371 lockdep_assert_held_read(&root->fs_info->commit_root_sem);
7372
7373 /*
7374 * Roots used for send operations are readonly and no one can add,
7375 * update or remove keys from them, so we should be able to find our
7376 * key again. The only exception is deduplication, which can operate on
7377 * readonly roots and add, update or remove keys to/from them - but at
7378 * the moment we don't allow it to run in parallel with send.
7379 */
7380 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7381 ASSERT(ret <= 0);
7382 if (ret > 0) {
7383 btrfs_print_tree(path->nodes[path->lowest_level], false);
7384 btrfs_err(root->fs_info,
7385 "send: key (%llu %u %llu) not found in %s root %llu, lowest_level %d, slot %d",
7386 key->objectid, key->type, key->offset,
7387 (root == sctx->parent_root ? "parent" : "send"),
7388 btrfs_root_id(root), path->lowest_level,
7389 path->slots[path->lowest_level]);
7390 return -EUCLEAN;
7391 }
7392
7393 return ret;
7394 }
7395
7396 static int full_send_tree(struct send_ctx *sctx)
7397 {
7398 int ret;
7399 struct btrfs_root *send_root = sctx->send_root;
7400 struct btrfs_key key;
7401 struct btrfs_fs_info *fs_info = send_root->fs_info;
7402 struct btrfs_path *path;
7403
7404 path = alloc_path_for_send();
7405 if (!path)
7406 return -ENOMEM;
7407 path->reada = READA_FORWARD_ALWAYS;
7408
7409 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
7410 key.type = BTRFS_INODE_ITEM_KEY;
7411 key.offset = 0;
7412
7413 down_read(&fs_info->commit_root_sem);
7414 sctx->last_reloc_trans = fs_info->last_reloc_trans;
7415 up_read(&fs_info->commit_root_sem);
7416
7417 ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0);
7418 if (ret < 0)
7419 goto out;
7420 if (ret)
7421 goto out_finish;
7422
7423 while (1) {
7424 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
7425
7426 ret = changed_cb(path, NULL, &key,
7427 BTRFS_COMPARE_TREE_NEW, sctx);
7428 if (ret < 0)
7429 goto out;
7430
7431 down_read(&fs_info->commit_root_sem);
7432 if (fs_info->last_reloc_trans > sctx->last_reloc_trans) {
7433 sctx->last_reloc_trans = fs_info->last_reloc_trans;
7434 up_read(&fs_info->commit_root_sem);
7435 /*
7436 * A transaction used for relocating a block group was
7437 * committed or is about to finish its commit. Release
7438 * our path (leaf) and restart the search, so that we
7439 * avoid operating on any file extent items that are
7440 * stale, with a disk_bytenr that reflects a pre
7441 * relocation value. This way we avoid as much as
7442 * possible to fallback to regular writes when checking
7443 * if we can clone file ranges.
7444 */
7445 btrfs_release_path(path);
7446 ret = search_key_again(sctx, send_root, path, &key);
7447 if (ret < 0)
7448 goto out;
7449 } else {
7450 up_read(&fs_info->commit_root_sem);
7451 }
7452
7453 ret = btrfs_next_item(send_root, path);
7454 if (ret < 0)
7455 goto out;
7456 if (ret) {
7457 ret = 0;
7458 break;
7459 }
7460 }
7461
7462 out_finish:
7463 ret = finish_inode_if_needed(sctx, 1);
7464
7465 out:
7466 btrfs_free_path(path);
7467 return ret;
7468 }
7469
7470 static int replace_node_with_clone(struct btrfs_path *path, int level)
7471 {
7472 struct extent_buffer *clone;
7473
7474 clone = btrfs_clone_extent_buffer(path->nodes[level]);
7475 if (!clone)
7476 return -ENOMEM;
7477
7478 free_extent_buffer(path->nodes[level]);
7479 path->nodes[level] = clone;
7480
7481 return 0;
7482 }
7483
7484 static int tree_move_down(struct btrfs_path *path, int *level, u64 reada_min_gen)
7485 {
7486 struct extent_buffer *eb;
7487 struct extent_buffer *parent = path->nodes[*level];
7488 int slot = path->slots[*level];
7489 const int nritems = btrfs_header_nritems(parent);
7490 u64 reada_max;
7491 u64 reada_done = 0;
7492
7493 lockdep_assert_held_read(&parent->fs_info->commit_root_sem);
7494 ASSERT(*level != 0);
7495
7496 eb = btrfs_read_node_slot(parent, slot);
7497 if (IS_ERR(eb))
7498 return PTR_ERR(eb);
7499
7500 /*
7501 * Trigger readahead for the next leaves we will process, so that it is
7502 * very likely that when we need them they are already in memory and we
7503 * will not block on disk IO. For nodes we only do readahead for one,
7504 * since the time window between processing nodes is typically larger.
7505 */
7506 reada_max = (*level == 1 ? SZ_128K : eb->fs_info->nodesize);
7507
7508 for (slot++; slot < nritems && reada_done < reada_max; slot++) {
7509 if (btrfs_node_ptr_generation(parent, slot) > reada_min_gen) {
7510 btrfs_readahead_node_child(parent, slot);
7511 reada_done += eb->fs_info->nodesize;
7512 }
7513 }
7514
7515 path->nodes[*level - 1] = eb;
7516 path->slots[*level - 1] = 0;
7517 (*level)--;
7518
7519 if (*level == 0)
7520 return replace_node_with_clone(path, 0);
7521
7522 return 0;
7523 }
7524
7525 static int tree_move_next_or_upnext(struct btrfs_path *path,
7526 int *level, int root_level)
7527 {
7528 int ret = 0;
7529 int nritems;
7530 nritems = btrfs_header_nritems(path->nodes[*level]);
7531
7532 path->slots[*level]++;
7533
7534 while (path->slots[*level] >= nritems) {
7535 if (*level == root_level) {
7536 path->slots[*level] = nritems - 1;
7537 return -1;
7538 }
7539
7540 /* move upnext */
7541 path->slots[*level] = 0;
7542 free_extent_buffer(path->nodes[*level]);
7543 path->nodes[*level] = NULL;
7544 (*level)++;
7545 path->slots[*level]++;
7546
7547 nritems = btrfs_header_nritems(path->nodes[*level]);
7548 ret = 1;
7549 }
7550 return ret;
7551 }
7552
7553 /*
7554 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
7555 * or down.
7556 */
7557 static int tree_advance(struct btrfs_path *path,
7558 int *level, int root_level,
7559 int allow_down,
7560 struct btrfs_key *key,
7561 u64 reada_min_gen)
7562 {
7563 int ret;
7564
7565 if (*level == 0 || !allow_down) {
7566 ret = tree_move_next_or_upnext(path, level, root_level);
7567 } else {
7568 ret = tree_move_down(path, level, reada_min_gen);
7569 }
7570
7571 /*
7572 * Even if we have reached the end of a tree, ret is -1, update the key
7573 * anyway, so that in case we need to restart due to a block group
7574 * relocation, we can assert that the last key of the root node still
7575 * exists in the tree.
7576 */
7577 if (*level == 0)
7578 btrfs_item_key_to_cpu(path->nodes[*level], key,
7579 path->slots[*level]);
7580 else
7581 btrfs_node_key_to_cpu(path->nodes[*level], key,
7582 path->slots[*level]);
7583
7584 return ret;
7585 }
7586
7587 static int tree_compare_item(struct btrfs_path *left_path,
7588 struct btrfs_path *right_path,
7589 char *tmp_buf)
7590 {
7591 int cmp;
7592 int len1, len2;
7593 unsigned long off1, off2;
7594
7595 len1 = btrfs_item_size(left_path->nodes[0], left_path->slots[0]);
7596 len2 = btrfs_item_size(right_path->nodes[0], right_path->slots[0]);
7597 if (len1 != len2)
7598 return 1;
7599
7600 off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]);
7601 off2 = btrfs_item_ptr_offset(right_path->nodes[0],
7602 right_path->slots[0]);
7603
7604 read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1);
7605
7606 cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1);
7607 if (cmp)
7608 return 1;
7609 return 0;
7610 }
7611
7612 /*
7613 * A transaction used for relocating a block group was committed or is about to
7614 * finish its commit. Release our paths and restart the search, so that we are
7615 * not using stale extent buffers:
7616 *
7617 * 1) For levels > 0, we are only holding references of extent buffers, without
7618 * any locks on them, which does not prevent them from having been relocated
7619 * and reallocated after the last time we released the commit root semaphore.
7620 * The exception are the root nodes, for which we always have a clone, see
7621 * the comment at btrfs_compare_trees();
7622 *
7623 * 2) For leaves, level 0, we are holding copies (clones) of extent buffers, so
7624 * we are safe from the concurrent relocation and reallocation. However they
7625 * can have file extent items with a pre relocation disk_bytenr value, so we
7626 * restart the start from the current commit roots and clone the new leaves so
7627 * that we get the post relocation disk_bytenr values. Not doing so, could
7628 * make us clone the wrong data in case there are new extents using the old
7629 * disk_bytenr that happen to be shared.
7630 */
7631 static int restart_after_relocation(struct btrfs_path *left_path,
7632 struct btrfs_path *right_path,
7633 const struct btrfs_key *left_key,
7634 const struct btrfs_key *right_key,
7635 int left_level,
7636 int right_level,
7637 const struct send_ctx *sctx)
7638 {
7639 int root_level;
7640 int ret;
7641
7642 lockdep_assert_held_read(&sctx->send_root->fs_info->commit_root_sem);
7643
7644 btrfs_release_path(left_path);
7645 btrfs_release_path(right_path);
7646
7647 /*
7648 * Since keys can not be added or removed to/from our roots because they
7649 * are readonly and we do not allow deduplication to run in parallel
7650 * (which can add, remove or change keys), the layout of the trees should
7651 * not change.
7652 */
7653 left_path->lowest_level = left_level;
7654 ret = search_key_again(sctx, sctx->send_root, left_path, left_key);
7655 if (ret < 0)
7656 return ret;
7657
7658 right_path->lowest_level = right_level;
7659 ret = search_key_again(sctx, sctx->parent_root, right_path, right_key);
7660 if (ret < 0)
7661 return ret;
7662
7663 /*
7664 * If the lowest level nodes are leaves, clone them so that they can be
7665 * safely used by changed_cb() while not under the protection of the
7666 * commit root semaphore, even if relocation and reallocation happens in
7667 * parallel.
7668 */
7669 if (left_level == 0) {
7670 ret = replace_node_with_clone(left_path, 0);
7671 if (ret < 0)
7672 return ret;
7673 }
7674
7675 if (right_level == 0) {
7676 ret = replace_node_with_clone(right_path, 0);
7677 if (ret < 0)
7678 return ret;
7679 }
7680
7681 /*
7682 * Now clone the root nodes (unless they happen to be the leaves we have
7683 * already cloned). This is to protect against concurrent snapshotting of
7684 * the send and parent roots (see the comment at btrfs_compare_trees()).
7685 */
7686 root_level = btrfs_header_level(sctx->send_root->commit_root);
7687 if (root_level > 0) {
7688 ret = replace_node_with_clone(left_path, root_level);
7689 if (ret < 0)
7690 return ret;
7691 }
7692
7693 root_level = btrfs_header_level(sctx->parent_root->commit_root);
7694 if (root_level > 0) {
7695 ret = replace_node_with_clone(right_path, root_level);
7696 if (ret < 0)
7697 return ret;
7698 }
7699
7700 return 0;
7701 }
7702
7703 /*
7704 * This function compares two trees and calls the provided callback for
7705 * every changed/new/deleted item it finds.
7706 * If shared tree blocks are encountered, whole subtrees are skipped, making
7707 * the compare pretty fast on snapshotted subvolumes.
7708 *
7709 * This currently works on commit roots only. As commit roots are read only,
7710 * we don't do any locking. The commit roots are protected with transactions.
7711 * Transactions are ended and rejoined when a commit is tried in between.
7712 *
7713 * This function checks for modifications done to the trees while comparing.
7714 * If it detects a change, it aborts immediately.
7715 */
7716 static int btrfs_compare_trees(struct btrfs_root *left_root,
7717 struct btrfs_root *right_root, struct send_ctx *sctx)
7718 {
7719 struct btrfs_fs_info *fs_info = left_root->fs_info;
7720 int ret;
7721 int cmp;
7722 struct btrfs_path *left_path = NULL;
7723 struct btrfs_path *right_path = NULL;
7724 struct btrfs_key left_key;
7725 struct btrfs_key right_key;
7726 char *tmp_buf = NULL;
7727 int left_root_level;
7728 int right_root_level;
7729 int left_level;
7730 int right_level;
7731 int left_end_reached = 0;
7732 int right_end_reached = 0;
7733 int advance_left = 0;
7734 int advance_right = 0;
7735 u64 left_blockptr;
7736 u64 right_blockptr;
7737 u64 left_gen;
7738 u64 right_gen;
7739 u64 reada_min_gen;
7740
7741 left_path = btrfs_alloc_path();
7742 if (!left_path) {
7743 ret = -ENOMEM;
7744 goto out;
7745 }
7746 right_path = btrfs_alloc_path();
7747 if (!right_path) {
7748 ret = -ENOMEM;
7749 goto out;
7750 }
7751
7752 tmp_buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
7753 if (!tmp_buf) {
7754 ret = -ENOMEM;
7755 goto out;
7756 }
7757
7758 left_path->search_commit_root = 1;
7759 left_path->skip_locking = 1;
7760 right_path->search_commit_root = 1;
7761 right_path->skip_locking = 1;
7762
7763 /*
7764 * Strategy: Go to the first items of both trees. Then do
7765 *
7766 * If both trees are at level 0
7767 * Compare keys of current items
7768 * If left < right treat left item as new, advance left tree
7769 * and repeat
7770 * If left > right treat right item as deleted, advance right tree
7771 * and repeat
7772 * If left == right do deep compare of items, treat as changed if
7773 * needed, advance both trees and repeat
7774 * If both trees are at the same level but not at level 0
7775 * Compare keys of current nodes/leafs
7776 * If left < right advance left tree and repeat
7777 * If left > right advance right tree and repeat
7778 * If left == right compare blockptrs of the next nodes/leafs
7779 * If they match advance both trees but stay at the same level
7780 * and repeat
7781 * If they don't match advance both trees while allowing to go
7782 * deeper and repeat
7783 * If tree levels are different
7784 * Advance the tree that needs it and repeat
7785 *
7786 * Advancing a tree means:
7787 * If we are at level 0, try to go to the next slot. If that's not
7788 * possible, go one level up and repeat. Stop when we found a level
7789 * where we could go to the next slot. We may at this point be on a
7790 * node or a leaf.
7791 *
7792 * If we are not at level 0 and not on shared tree blocks, go one
7793 * level deeper.
7794 *
7795 * If we are not at level 0 and on shared tree blocks, go one slot to
7796 * the right if possible or go up and right.
7797 */
7798
7799 down_read(&fs_info->commit_root_sem);
7800 left_level = btrfs_header_level(left_root->commit_root);
7801 left_root_level = left_level;
7802 /*
7803 * We clone the root node of the send and parent roots to prevent races
7804 * with snapshot creation of these roots. Snapshot creation COWs the
7805 * root node of a tree, so after the transaction is committed the old
7806 * extent can be reallocated while this send operation is still ongoing.
7807 * So we clone them, under the commit root semaphore, to be race free.
7808 */
7809 left_path->nodes[left_level] =
7810 btrfs_clone_extent_buffer(left_root->commit_root);
7811 if (!left_path->nodes[left_level]) {
7812 ret = -ENOMEM;
7813 goto out_unlock;
7814 }
7815
7816 right_level = btrfs_header_level(right_root->commit_root);
7817 right_root_level = right_level;
7818 right_path->nodes[right_level] =
7819 btrfs_clone_extent_buffer(right_root->commit_root);
7820 if (!right_path->nodes[right_level]) {
7821 ret = -ENOMEM;
7822 goto out_unlock;
7823 }
7824 /*
7825 * Our right root is the parent root, while the left root is the "send"
7826 * root. We know that all new nodes/leaves in the left root must have
7827 * a generation greater than the right root's generation, so we trigger
7828 * readahead for those nodes and leaves of the left root, as we know we
7829 * will need to read them at some point.
7830 */
7831 reada_min_gen = btrfs_header_generation(right_root->commit_root);
7832
7833 if (left_level == 0)
7834 btrfs_item_key_to_cpu(left_path->nodes[left_level],
7835 &left_key, left_path->slots[left_level]);
7836 else
7837 btrfs_node_key_to_cpu(left_path->nodes[left_level],
7838 &left_key, left_path->slots[left_level]);
7839 if (right_level == 0)
7840 btrfs_item_key_to_cpu(right_path->nodes[right_level],
7841 &right_key, right_path->slots[right_level]);
7842 else
7843 btrfs_node_key_to_cpu(right_path->nodes[right_level],
7844 &right_key, right_path->slots[right_level]);
7845
7846 sctx->last_reloc_trans = fs_info->last_reloc_trans;
7847
7848 while (1) {
7849 if (need_resched() ||
7850 rwsem_is_contended(&fs_info->commit_root_sem)) {
7851 up_read(&fs_info->commit_root_sem);
7852 cond_resched();
7853 down_read(&fs_info->commit_root_sem);
7854 }
7855
7856 if (fs_info->last_reloc_trans > sctx->last_reloc_trans) {
7857 ret = restart_after_relocation(left_path, right_path,
7858 &left_key, &right_key,
7859 left_level, right_level,
7860 sctx);
7861 if (ret < 0)
7862 goto out_unlock;
7863 sctx->last_reloc_trans = fs_info->last_reloc_trans;
7864 }
7865
7866 if (advance_left && !left_end_reached) {
7867 ret = tree_advance(left_path, &left_level,
7868 left_root_level,
7869 advance_left != ADVANCE_ONLY_NEXT,
7870 &left_key, reada_min_gen);
7871 if (ret == -1)
7872 left_end_reached = ADVANCE;
7873 else if (ret < 0)
7874 goto out_unlock;
7875 advance_left = 0;
7876 }
7877 if (advance_right && !right_end_reached) {
7878 ret = tree_advance(right_path, &right_level,
7879 right_root_level,
7880 advance_right != ADVANCE_ONLY_NEXT,
7881 &right_key, reada_min_gen);
7882 if (ret == -1)
7883 right_end_reached = ADVANCE;
7884 else if (ret < 0)
7885 goto out_unlock;
7886 advance_right = 0;
7887 }
7888
7889 if (left_end_reached && right_end_reached) {
7890 ret = 0;
7891 goto out_unlock;
7892 } else if (left_end_reached) {
7893 if (right_level == 0) {
7894 up_read(&fs_info->commit_root_sem);
7895 ret = changed_cb(left_path, right_path,
7896 &right_key,
7897 BTRFS_COMPARE_TREE_DELETED,
7898 sctx);
7899 if (ret < 0)
7900 goto out;
7901 down_read(&fs_info->commit_root_sem);
7902 }
7903 advance_right = ADVANCE;
7904 continue;
7905 } else if (right_end_reached) {
7906 if (left_level == 0) {
7907 up_read(&fs_info->commit_root_sem);
7908 ret = changed_cb(left_path, right_path,
7909 &left_key,
7910 BTRFS_COMPARE_TREE_NEW,
7911 sctx);
7912 if (ret < 0)
7913 goto out;
7914 down_read(&fs_info->commit_root_sem);
7915 }
7916 advance_left = ADVANCE;
7917 continue;
7918 }
7919
7920 if (left_level == 0 && right_level == 0) {
7921 up_read(&fs_info->commit_root_sem);
7922 cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
7923 if (cmp < 0) {
7924 ret = changed_cb(left_path, right_path,
7925 &left_key,
7926 BTRFS_COMPARE_TREE_NEW,
7927 sctx);
7928 advance_left = ADVANCE;
7929 } else if (cmp > 0) {
7930 ret = changed_cb(left_path, right_path,
7931 &right_key,
7932 BTRFS_COMPARE_TREE_DELETED,
7933 sctx);
7934 advance_right = ADVANCE;
7935 } else {
7936 enum btrfs_compare_tree_result result;
7937
7938 WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
7939 ret = tree_compare_item(left_path, right_path,
7940 tmp_buf);
7941 if (ret)
7942 result = BTRFS_COMPARE_TREE_CHANGED;
7943 else
7944 result = BTRFS_COMPARE_TREE_SAME;
7945 ret = changed_cb(left_path, right_path,
7946 &left_key, result, sctx);
7947 advance_left = ADVANCE;
7948 advance_right = ADVANCE;
7949 }
7950
7951 if (ret < 0)
7952 goto out;
7953 down_read(&fs_info->commit_root_sem);
7954 } else if (left_level == right_level) {
7955 cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
7956 if (cmp < 0) {
7957 advance_left = ADVANCE;
7958 } else if (cmp > 0) {
7959 advance_right = ADVANCE;
7960 } else {
7961 left_blockptr = btrfs_node_blockptr(
7962 left_path->nodes[left_level],
7963 left_path->slots[left_level]);
7964 right_blockptr = btrfs_node_blockptr(
7965 right_path->nodes[right_level],
7966 right_path->slots[right_level]);
7967 left_gen = btrfs_node_ptr_generation(
7968 left_path->nodes[left_level],
7969 left_path->slots[left_level]);
7970 right_gen = btrfs_node_ptr_generation(
7971 right_path->nodes[right_level],
7972 right_path->slots[right_level]);
7973 if (left_blockptr == right_blockptr &&
7974 left_gen == right_gen) {
7975 /*
7976 * As we're on a shared block, don't
7977 * allow to go deeper.
7978 */
7979 advance_left = ADVANCE_ONLY_NEXT;
7980 advance_right = ADVANCE_ONLY_NEXT;
7981 } else {
7982 advance_left = ADVANCE;
7983 advance_right = ADVANCE;
7984 }
7985 }
7986 } else if (left_level < right_level) {
7987 advance_right = ADVANCE;
7988 } else {
7989 advance_left = ADVANCE;
7990 }
7991 }
7992
7993 out_unlock:
7994 up_read(&fs_info->commit_root_sem);
7995 out:
7996 btrfs_free_path(left_path);
7997 btrfs_free_path(right_path);
7998 kvfree(tmp_buf);
7999 return ret;
8000 }
8001
8002 static int send_subvol(struct send_ctx *sctx)
8003 {
8004 int ret;
8005
8006 if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_STREAM_HEADER)) {
8007 ret = send_header(sctx);
8008 if (ret < 0)
8009 goto out;
8010 }
8011
8012 ret = send_subvol_begin(sctx);
8013 if (ret < 0)
8014 goto out;
8015
8016 if (sctx->parent_root) {
8017 ret = btrfs_compare_trees(sctx->send_root, sctx->parent_root, sctx);
8018 if (ret < 0)
8019 goto out;
8020 ret = finish_inode_if_needed(sctx, 1);
8021 if (ret < 0)
8022 goto out;
8023 } else {
8024 ret = full_send_tree(sctx);
8025 if (ret < 0)
8026 goto out;
8027 }
8028
8029 out:
8030 free_recorded_refs(sctx);
8031 return ret;
8032 }
8033
8034 /*
8035 * If orphan cleanup did remove any orphans from a root, it means the tree
8036 * was modified and therefore the commit root is not the same as the current
8037 * root anymore. This is a problem, because send uses the commit root and
8038 * therefore can see inode items that don't exist in the current root anymore,
8039 * and for example make calls to btrfs_iget, which will do tree lookups based
8040 * on the current root and not on the commit root. Those lookups will fail,
8041 * returning a -ESTALE error, and making send fail with that error. So make
8042 * sure a send does not see any orphans we have just removed, and that it will
8043 * see the same inodes regardless of whether a transaction commit happened
8044 * before it started (meaning that the commit root will be the same as the
8045 * current root) or not.
8046 */
8047 static int ensure_commit_roots_uptodate(struct send_ctx *sctx)
8048 {
8049 struct btrfs_root *root = sctx->parent_root;
8050
8051 if (root && root->node != root->commit_root)
8052 return btrfs_commit_current_transaction(root);
8053
8054 for (int i = 0; i < sctx->clone_roots_cnt; i++) {
8055 root = sctx->clone_roots[i].root;
8056 if (root->node != root->commit_root)
8057 return btrfs_commit_current_transaction(root);
8058 }
8059
8060 return 0;
8061 }
8062
8063 /*
8064 * Make sure any existing dellaloc is flushed for any root used by a send
8065 * operation so that we do not miss any data and we do not race with writeback
8066 * finishing and changing a tree while send is using the tree. This could
8067 * happen if a subvolume is in RW mode, has delalloc, is turned to RO mode and
8068 * a send operation then uses the subvolume.
8069 * After flushing delalloc ensure_commit_roots_uptodate() must be called.
8070 */
8071 static int flush_delalloc_roots(struct send_ctx *sctx)
8072 {
8073 struct btrfs_root *root = sctx->parent_root;
8074 int ret;
8075 int i;
8076
8077 if (root) {
8078 ret = btrfs_start_delalloc_snapshot(root, false);
8079 if (ret)
8080 return ret;
8081 btrfs_wait_ordered_extents(root, U64_MAX, NULL);
8082 }
8083
8084 for (i = 0; i < sctx->clone_roots_cnt; i++) {
8085 root = sctx->clone_roots[i].root;
8086 ret = btrfs_start_delalloc_snapshot(root, false);
8087 if (ret)
8088 return ret;
8089 btrfs_wait_ordered_extents(root, U64_MAX, NULL);
8090 }
8091
8092 return 0;
8093 }
8094
8095 static void btrfs_root_dec_send_in_progress(struct btrfs_root* root)
8096 {
8097 spin_lock(&root->root_item_lock);
8098 root->send_in_progress--;
8099 /*
8100 * Not much left to do, we don't know why it's unbalanced and
8101 * can't blindly reset it to 0.
8102 */
8103 if (root->send_in_progress < 0)
8104 btrfs_err(root->fs_info,
8105 "send_in_progress unbalanced %d root %llu",
8106 root->send_in_progress, btrfs_root_id(root));
8107 spin_unlock(&root->root_item_lock);
8108 }
8109
8110 static void dedupe_in_progress_warn(const struct btrfs_root *root)
8111 {
8112 btrfs_warn_rl(root->fs_info,
8113 "cannot use root %llu for send while deduplications on it are in progress (%d in progress)",
8114 btrfs_root_id(root), root->dedupe_in_progress);
8115 }
8116
8117 long btrfs_ioctl_send(struct btrfs_inode *inode, const struct btrfs_ioctl_send_args *arg)
8118 {
8119 int ret = 0;
8120 struct btrfs_root *send_root = inode->root;
8121 struct btrfs_fs_info *fs_info = send_root->fs_info;
8122 struct btrfs_root *clone_root;
8123 struct send_ctx *sctx = NULL;
8124 u32 i;
8125 u64 *clone_sources_tmp = NULL;
8126 int clone_sources_to_rollback = 0;
8127 size_t alloc_size;
8128 int sort_clone_roots = 0;
8129 struct btrfs_lru_cache_entry *entry;
8130 struct btrfs_lru_cache_entry *tmp;
8131
8132 if (!capable(CAP_SYS_ADMIN))
8133 return -EPERM;
8134
8135 /*
8136 * The subvolume must remain read-only during send, protect against
8137 * making it RW. This also protects against deletion.
8138 */
8139 spin_lock(&send_root->root_item_lock);
8140 if (btrfs_root_readonly(send_root) && send_root->dedupe_in_progress) {
8141 dedupe_in_progress_warn(send_root);
8142 spin_unlock(&send_root->root_item_lock);
8143 return -EAGAIN;
8144 }
8145 send_root->send_in_progress++;
8146 spin_unlock(&send_root->root_item_lock);
8147
8148 /*
8149 * Userspace tools do the checks and warn the user if it's
8150 * not RO.
8151 */
8152 if (!btrfs_root_readonly(send_root)) {
8153 ret = -EPERM;
8154 goto out;
8155 }
8156
8157 /*
8158 * Check that we don't overflow at later allocations, we request
8159 * clone_sources_count + 1 items, and compare to unsigned long inside
8160 * access_ok. Also set an upper limit for allocation size so this can't
8161 * easily exhaust memory. Max number of clone sources is about 200K.
8162 */
8163 if (arg->clone_sources_count > SZ_8M / sizeof(struct clone_root)) {
8164 ret = -EINVAL;
8165 goto out;
8166 }
8167
8168 if (arg->flags & ~BTRFS_SEND_FLAG_MASK) {
8169 ret = -EOPNOTSUPP;
8170 goto out;
8171 }
8172
8173 sctx = kzalloc(sizeof(struct send_ctx), GFP_KERNEL);
8174 if (!sctx) {
8175 ret = -ENOMEM;
8176 goto out;
8177 }
8178
8179 INIT_LIST_HEAD(&sctx->new_refs);
8180 INIT_LIST_HEAD(&sctx->deleted_refs);
8181
8182 btrfs_lru_cache_init(&sctx->name_cache, SEND_MAX_NAME_CACHE_SIZE);
8183 btrfs_lru_cache_init(&sctx->backref_cache, SEND_MAX_BACKREF_CACHE_SIZE);
8184 btrfs_lru_cache_init(&sctx->dir_created_cache,
8185 SEND_MAX_DIR_CREATED_CACHE_SIZE);
8186 /*
8187 * This cache is periodically trimmed to a fixed size elsewhere, see
8188 * cache_dir_utimes() and trim_dir_utimes_cache().
8189 */
8190 btrfs_lru_cache_init(&sctx->dir_utimes_cache, 0);
8191
8192 sctx->pending_dir_moves = RB_ROOT;
8193 sctx->waiting_dir_moves = RB_ROOT;
8194 sctx->orphan_dirs = RB_ROOT;
8195 sctx->rbtree_new_refs = RB_ROOT;
8196 sctx->rbtree_deleted_refs = RB_ROOT;
8197
8198 sctx->flags = arg->flags;
8199
8200 if (arg->flags & BTRFS_SEND_FLAG_VERSION) {
8201 if (arg->version > BTRFS_SEND_STREAM_VERSION) {
8202 ret = -EPROTO;
8203 goto out;
8204 }
8205 /* Zero means "use the highest version" */
8206 sctx->proto = arg->version ?: BTRFS_SEND_STREAM_VERSION;
8207 } else {
8208 sctx->proto = 1;
8209 }
8210 if ((arg->flags & BTRFS_SEND_FLAG_COMPRESSED) && sctx->proto < 2) {
8211 ret = -EINVAL;
8212 goto out;
8213 }
8214
8215 sctx->send_filp = fget(arg->send_fd);
8216 if (!sctx->send_filp || !(sctx->send_filp->f_mode & FMODE_WRITE)) {
8217 ret = -EBADF;
8218 goto out;
8219 }
8220
8221 sctx->send_root = send_root;
8222 /*
8223 * Unlikely but possible, if the subvolume is marked for deletion but
8224 * is slow to remove the directory entry, send can still be started
8225 */
8226 if (btrfs_root_dead(sctx->send_root)) {
8227 ret = -EPERM;
8228 goto out;
8229 }
8230
8231 sctx->clone_roots_cnt = arg->clone_sources_count;
8232
8233 if (sctx->proto >= 2) {
8234 u32 send_buf_num_pages;
8235
8236 sctx->send_max_size = BTRFS_SEND_BUF_SIZE_V2;
8237 sctx->send_buf = vmalloc(sctx->send_max_size);
8238 if (!sctx->send_buf) {
8239 ret = -ENOMEM;
8240 goto out;
8241 }
8242 send_buf_num_pages = sctx->send_max_size >> PAGE_SHIFT;
8243 sctx->send_buf_pages = kcalloc(send_buf_num_pages,
8244 sizeof(*sctx->send_buf_pages),
8245 GFP_KERNEL);
8246 if (!sctx->send_buf_pages) {
8247 ret = -ENOMEM;
8248 goto out;
8249 }
8250 for (i = 0; i < send_buf_num_pages; i++) {
8251 sctx->send_buf_pages[i] =
8252 vmalloc_to_page(sctx->send_buf + (i << PAGE_SHIFT));
8253 }
8254 } else {
8255 sctx->send_max_size = BTRFS_SEND_BUF_SIZE_V1;
8256 sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL);
8257 }
8258 if (!sctx->send_buf) {
8259 ret = -ENOMEM;
8260 goto out;
8261 }
8262
8263 sctx->clone_roots = kvcalloc(arg->clone_sources_count + 1,
8264 sizeof(*sctx->clone_roots),
8265 GFP_KERNEL);
8266 if (!sctx->clone_roots) {
8267 ret = -ENOMEM;
8268 goto out;
8269 }
8270
8271 alloc_size = array_size(sizeof(*arg->clone_sources),
8272 arg->clone_sources_count);
8273
8274 if (arg->clone_sources_count) {
8275 clone_sources_tmp = kvmalloc(alloc_size, GFP_KERNEL);
8276 if (!clone_sources_tmp) {
8277 ret = -ENOMEM;
8278 goto out;
8279 }
8280
8281 ret = copy_from_user(clone_sources_tmp, arg->clone_sources,
8282 alloc_size);
8283 if (ret) {
8284 ret = -EFAULT;
8285 goto out;
8286 }
8287
8288 for (i = 0; i < arg->clone_sources_count; i++) {
8289 clone_root = btrfs_get_fs_root(fs_info,
8290 clone_sources_tmp[i], true);
8291 if (IS_ERR(clone_root)) {
8292 ret = PTR_ERR(clone_root);
8293 goto out;
8294 }
8295 spin_lock(&clone_root->root_item_lock);
8296 if (!btrfs_root_readonly(clone_root) ||
8297 btrfs_root_dead(clone_root)) {
8298 spin_unlock(&clone_root->root_item_lock);
8299 btrfs_put_root(clone_root);
8300 ret = -EPERM;
8301 goto out;
8302 }
8303 if (clone_root->dedupe_in_progress) {
8304 dedupe_in_progress_warn(clone_root);
8305 spin_unlock(&clone_root->root_item_lock);
8306 btrfs_put_root(clone_root);
8307 ret = -EAGAIN;
8308 goto out;
8309 }
8310 clone_root->send_in_progress++;
8311 spin_unlock(&clone_root->root_item_lock);
8312
8313 sctx->clone_roots[i].root = clone_root;
8314 clone_sources_to_rollback = i + 1;
8315 }
8316 kvfree(clone_sources_tmp);
8317 clone_sources_tmp = NULL;
8318 }
8319
8320 if (arg->parent_root) {
8321 sctx->parent_root = btrfs_get_fs_root(fs_info, arg->parent_root,
8322 true);
8323 if (IS_ERR(sctx->parent_root)) {
8324 ret = PTR_ERR(sctx->parent_root);
8325 goto out;
8326 }
8327
8328 spin_lock(&sctx->parent_root->root_item_lock);
8329 sctx->parent_root->send_in_progress++;
8330 if (!btrfs_root_readonly(sctx->parent_root) ||
8331 btrfs_root_dead(sctx->parent_root)) {
8332 spin_unlock(&sctx->parent_root->root_item_lock);
8333 ret = -EPERM;
8334 goto out;
8335 }
8336 if (sctx->parent_root->dedupe_in_progress) {
8337 dedupe_in_progress_warn(sctx->parent_root);
8338 spin_unlock(&sctx->parent_root->root_item_lock);
8339 ret = -EAGAIN;
8340 goto out;
8341 }
8342 spin_unlock(&sctx->parent_root->root_item_lock);
8343 }
8344
8345 /*
8346 * Clones from send_root are allowed, but only if the clone source
8347 * is behind the current send position. This is checked while searching
8348 * for possible clone sources.
8349 */
8350 sctx->clone_roots[sctx->clone_roots_cnt++].root =
8351 btrfs_grab_root(sctx->send_root);
8352
8353 /* We do a bsearch later */
8354 sort(sctx->clone_roots, sctx->clone_roots_cnt,
8355 sizeof(*sctx->clone_roots), __clone_root_cmp_sort,
8356 NULL);
8357 sort_clone_roots = 1;
8358
8359 ret = flush_delalloc_roots(sctx);
8360 if (ret)
8361 goto out;
8362
8363 ret = ensure_commit_roots_uptodate(sctx);
8364 if (ret)
8365 goto out;
8366
8367 ret = send_subvol(sctx);
8368 if (ret < 0)
8369 goto out;
8370
8371 btrfs_lru_cache_for_each_entry_safe(&sctx->dir_utimes_cache, entry, tmp) {
8372 ret = send_utimes(sctx, entry->key, entry->gen);
8373 if (ret < 0)
8374 goto out;
8375 btrfs_lru_cache_remove(&sctx->dir_utimes_cache, entry);
8376 }
8377
8378 if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_END_CMD)) {
8379 ret = begin_cmd(sctx, BTRFS_SEND_C_END);
8380 if (ret < 0)
8381 goto out;
8382 ret = send_cmd(sctx);
8383 if (ret < 0)
8384 goto out;
8385 }
8386
8387 out:
8388 WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->pending_dir_moves));
8389 while (sctx && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)) {
8390 struct rb_node *n;
8391 struct pending_dir_move *pm;
8392
8393 n = rb_first(&sctx->pending_dir_moves);
8394 pm = rb_entry(n, struct pending_dir_move, node);
8395 while (!list_empty(&pm->list)) {
8396 struct pending_dir_move *pm2;
8397
8398 pm2 = list_first_entry(&pm->list,
8399 struct pending_dir_move, list);
8400 free_pending_move(sctx, pm2);
8401 }
8402 free_pending_move(sctx, pm);
8403 }
8404
8405 WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves));
8406 while (sctx && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) {
8407 struct rb_node *n;
8408 struct waiting_dir_move *dm;
8409
8410 n = rb_first(&sctx->waiting_dir_moves);
8411 dm = rb_entry(n, struct waiting_dir_move, node);
8412 rb_erase(&dm->node, &sctx->waiting_dir_moves);
8413 kfree(dm);
8414 }
8415
8416 WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->orphan_dirs));
8417 while (sctx && !RB_EMPTY_ROOT(&sctx->orphan_dirs)) {
8418 struct rb_node *n;
8419 struct orphan_dir_info *odi;
8420
8421 n = rb_first(&sctx->orphan_dirs);
8422 odi = rb_entry(n, struct orphan_dir_info, node);
8423 free_orphan_dir_info(sctx, odi);
8424 }
8425
8426 if (sort_clone_roots) {
8427 for (i = 0; i < sctx->clone_roots_cnt; i++) {
8428 btrfs_root_dec_send_in_progress(
8429 sctx->clone_roots[i].root);
8430 btrfs_put_root(sctx->clone_roots[i].root);
8431 }
8432 } else {
8433 for (i = 0; sctx && i < clone_sources_to_rollback; i++) {
8434 btrfs_root_dec_send_in_progress(
8435 sctx->clone_roots[i].root);
8436 btrfs_put_root(sctx->clone_roots[i].root);
8437 }
8438
8439 btrfs_root_dec_send_in_progress(send_root);
8440 }
8441 if (sctx && !IS_ERR_OR_NULL(sctx->parent_root)) {
8442 btrfs_root_dec_send_in_progress(sctx->parent_root);
8443 btrfs_put_root(sctx->parent_root);
8444 }
8445
8446 kvfree(clone_sources_tmp);
8447
8448 if (sctx) {
8449 if (sctx->send_filp)
8450 fput(sctx->send_filp);
8451
8452 kvfree(sctx->clone_roots);
8453 kfree(sctx->send_buf_pages);
8454 kvfree(sctx->send_buf);
8455 kvfree(sctx->verity_descriptor);
8456
8457 close_current_inode(sctx);
8458
8459 btrfs_lru_cache_clear(&sctx->name_cache);
8460 btrfs_lru_cache_clear(&sctx->backref_cache);
8461 btrfs_lru_cache_clear(&sctx->dir_created_cache);
8462 btrfs_lru_cache_clear(&sctx->dir_utimes_cache);
8463
8464 kfree(sctx);
8465 }
8466
8467 return ret;
8468 }
8469
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