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