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
19 #include "send.h"
20 #include "backref.h"
21 #include "locking.h"
22 #include "disk-io.h"
23 #include "btrfs_inode.h"
24 #include "transaction.h"
25 #include "compression.h"
26 #include "xattr.h"
27
28 /*
29 * Maximum number of references an extent can have in order for us to attempt to
30 * issue clone operations instead of write operations. This currently exists to
31 * avoid hitting limitations of the backreference walking code (taking a lot of
32 * time and using too much memory for extents with large number of references).
33 */
34 #define SEND_MAX_EXTENT_REFS 64
35
36 /*
37 * A fs_path is a helper to dynamically build path names with unknown size.
38 * It reallocates the internal buffer on demand.
39 * It allows fast adding of path elements on the right side (normal path) and
40 * fast adding to the left side (reversed path). A reversed path can also be
41 * unreversed if needed.
42 */
43 struct fs_path {
44 union {
45 struct {
46 char *start;
47 char *end;
48
49 char *buf;
50 unsigned short buf_len:15;
51 unsigned short reversed:1;
52 char inline_buf[];
53 };
54 /*
55 * Average path length does not exceed 200 bytes, we'll have
56 * better packing in the slab and higher chance to satisfy
57 * a allocation later during send.
58 */
59 char pad[256];
60 };
61 };
62 #define FS_PATH_INLINE_SIZE \
63 (sizeof(struct fs_path) - offsetof(struct fs_path, inline_buf))
64
65
66 /* reused for each extent */
67 struct clone_root {
68 struct btrfs_root *root;
69 u64 ino;
70 u64 offset;
71
72 u64 found_refs;
73 };
74
75 #define SEND_CTX_MAX_NAME_CACHE_SIZE 128
76 #define SEND_CTX_NAME_CACHE_CLEAN_SIZE (SEND_CTX_MAX_NAME_CACHE_SIZE * 2)
77
78 struct send_ctx {
79 struct file *send_filp;
80 loff_t send_off;
81 char *send_buf;
82 u32 send_size;
83 u32 send_max_size;
84 u64 total_send_size;
85 u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];
86 u64 flags; /* 'flags' member of btrfs_ioctl_send_args is u64 */
87
88 struct btrfs_root *send_root;
89 struct btrfs_root *parent_root;
90 struct clone_root *clone_roots;
91 int clone_roots_cnt;
92
93 /* current state of the compare_tree call */
94 struct btrfs_path *left_path;
95 struct btrfs_path *right_path;
96 struct btrfs_key *cmp_key;
97
98 /*
99 * infos of the currently processed inode. In case of deleted inodes,
100 * these are the values from the deleted inode.
101 */
102 u64 cur_ino;
103 u64 cur_inode_gen;
104 int cur_inode_new;
105 int cur_inode_new_gen;
106 int cur_inode_deleted;
107 u64 cur_inode_size;
108 u64 cur_inode_mode;
109 u64 cur_inode_rdev;
110 u64 cur_inode_last_extent;
111 u64 cur_inode_next_write_offset;
112 bool ignore_cur_inode;
113
114 u64 send_progress;
115
116 struct list_head new_refs;
117 struct list_head deleted_refs;
118
119 struct radix_tree_root name_cache;
120 struct list_head name_cache_list;
121 int name_cache_size;
122
123 struct file_ra_state ra;
124
125 /*
126 * We process inodes by their increasing order, so if before an
127 * incremental send we reverse the parent/child relationship of
128 * directories such that a directory with a lower inode number was
129 * the parent of a directory with a higher inode number, and the one
130 * becoming the new parent got renamed too, we can't rename/move the
131 * directory with lower inode number when we finish processing it - we
132 * must process the directory with higher inode number first, then
133 * rename/move it and then rename/move the directory with lower inode
134 * number. Example follows.
135 *
136 * Tree state when the first send was performed:
137 *
138 * .
139 * |-- a (ino 257)
140 * |-- b (ino 258)
141 * |
142 * |
143 * |-- c (ino 259)
144 * | |-- d (ino 260)
145 * |
146 * |-- c2 (ino 261)
147 *
148 * Tree state when the second (incremental) send is performed:
149 *
150 * .
151 * |-- a (ino 257)
152 * |-- b (ino 258)
153 * |-- c2 (ino 261)
154 * |-- d2 (ino 260)
155 * |-- cc (ino 259)
156 *
157 * The sequence of steps that lead to the second state was:
158 *
159 * mv /a/b/c/d /a/b/c2/d2
160 * mv /a/b/c /a/b/c2/d2/cc
161 *
162 * "c" has lower inode number, but we can't move it (2nd mv operation)
163 * before we move "d", which has higher inode number.
164 *
165 * So we just memorize which move/rename operations must be performed
166 * later when their respective parent is processed and moved/renamed.
167 */
168
169 /* Indexed by parent directory inode number. */
170 struct rb_root pending_dir_moves;
171
172 /*
173 * Reverse index, indexed by the inode number of a directory that
174 * is waiting for the move/rename of its immediate parent before its
175 * own move/rename can be performed.
176 */
177 struct rb_root waiting_dir_moves;
178
179 /*
180 * A directory that is going to be rm'ed might have a child directory
181 * which is in the pending directory moves index above. In this case,
182 * the directory can only be removed after the move/rename of its child
183 * is performed. Example:
184 *
185 * Parent snapshot:
186 *
187 * . (ino 256)
188 * |-- a/ (ino 257)
189 * |-- b/ (ino 258)
190 * |-- c/ (ino 259)
191 * | |-- x/ (ino 260)
192 * |
193 * |-- y/ (ino 261)
194 *
195 * Send snapshot:
196 *
197 * . (ino 256)
198 * |-- a/ (ino 257)
199 * |-- b/ (ino 258)
200 * |-- YY/ (ino 261)
201 * |-- x/ (ino 260)
202 *
203 * Sequence of steps that lead to the send snapshot:
204 * rm -f /a/b/c/foo.txt
205 * mv /a/b/y /a/b/YY
206 * mv /a/b/c/x /a/b/YY
207 * rmdir /a/b/c
208 *
209 * When the child is processed, its move/rename is delayed until its
210 * parent is processed (as explained above), but all other operations
211 * like update utimes, chown, chgrp, etc, are performed and the paths
212 * that it uses for those operations must use the orphanized name of
213 * its parent (the directory we're going to rm later), so we need to
214 * memorize that name.
215 *
216 * Indexed by the inode number of the directory to be deleted.
217 */
218 struct rb_root orphan_dirs;
219 };
220
221 struct pending_dir_move {
222 struct rb_node node;
223 struct list_head list;
224 u64 parent_ino;
225 u64 ino;
226 u64 gen;
227 struct list_head update_refs;
228 };
229
230 struct waiting_dir_move {
231 struct rb_node node;
232 u64 ino;
233 /*
234 * There might be some directory that could not be removed because it
235 * was waiting for this directory inode to be moved first. Therefore
236 * after this directory is moved, we can try to rmdir the ino rmdir_ino.
237 */
238 u64 rmdir_ino;
239 u64 rmdir_gen;
240 bool orphanized;
241 };
242
243 struct orphan_dir_info {
244 struct rb_node node;
245 u64 ino;
246 u64 gen;
247 u64 last_dir_index_offset;
248 };
249
250 struct name_cache_entry {
251 struct list_head list;
252 /*
253 * radix_tree has only 32bit entries but we need to handle 64bit inums.
254 * We use the lower 32bit of the 64bit inum to store it in the tree. If
255 * more then one inum would fall into the same entry, we use radix_list
256 * to store the additional entries. radix_list is also used to store
257 * entries where two entries have the same inum but different
258 * generations.
259 */
260 struct list_head radix_list;
261 u64 ino;
262 u64 gen;
263 u64 parent_ino;
264 u64 parent_gen;
265 int ret;
266 int need_later_update;
267 int name_len;
268 char name[];
269 };
270
271 #define ADVANCE 1
272 #define ADVANCE_ONLY_NEXT -1
273
274 enum btrfs_compare_tree_result {
275 BTRFS_COMPARE_TREE_NEW,
276 BTRFS_COMPARE_TREE_DELETED,
277 BTRFS_COMPARE_TREE_CHANGED,
278 BTRFS_COMPARE_TREE_SAME,
279 };
280
281 __cold
282 static void inconsistent_snapshot_error(struct send_ctx *sctx,
283 enum btrfs_compare_tree_result result,
284 const char *what)
285 {
286 const char *result_string;
287
288 switch (result) {
289 case BTRFS_COMPARE_TREE_NEW:
290 result_string = "new";
291 break;
292 case BTRFS_COMPARE_TREE_DELETED:
293 result_string = "deleted";
294 break;
295 case BTRFS_COMPARE_TREE_CHANGED:
296 result_string = "updated";
297 break;
298 case BTRFS_COMPARE_TREE_SAME:
299 ASSERT(0);
300 result_string = "unchanged";
301 break;
302 default:
303 ASSERT(0);
304 result_string = "unexpected";
305 }
306
307 btrfs_err(sctx->send_root->fs_info,
308 "Send: inconsistent snapshot, found %s %s for inode %llu without updated inode item, send root is %llu, parent root is %llu",
309 result_string, what, sctx->cmp_key->objectid,
310 sctx->send_root->root_key.objectid,
311 (sctx->parent_root ?
312 sctx->parent_root->root_key.objectid : 0));
313 }
314
315 static int is_waiting_for_move(struct send_ctx *sctx, u64 ino);
316
317 static struct waiting_dir_move *
318 get_waiting_dir_move(struct send_ctx *sctx, u64 ino);
319
320 static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen);
321
322 static int need_send_hole(struct send_ctx *sctx)
323 {
324 return (sctx->parent_root && !sctx->cur_inode_new &&
325 !sctx->cur_inode_new_gen && !sctx->cur_inode_deleted &&
326 S_ISREG(sctx->cur_inode_mode));
327 }
328
329 static void fs_path_reset(struct fs_path *p)
330 {
331 if (p->reversed) {
332 p->start = p->buf + p->buf_len - 1;
333 p->end = p->start;
334 *p->start = 0;
335 } else {
336 p->start = p->buf;
337 p->end = p->start;
338 *p->start = 0;
339 }
340 }
341
342 static struct fs_path *fs_path_alloc(void)
343 {
344 struct fs_path *p;
345
346 p = kmalloc(sizeof(*p), GFP_KERNEL);
347 if (!p)
348 return NULL;
349 p->reversed = 0;
350 p->buf = p->inline_buf;
351 p->buf_len = FS_PATH_INLINE_SIZE;
352 fs_path_reset(p);
353 return p;
354 }
355
356 static struct fs_path *fs_path_alloc_reversed(void)
357 {
358 struct fs_path *p;
359
360 p = fs_path_alloc();
361 if (!p)
362 return NULL;
363 p->reversed = 1;
364 fs_path_reset(p);
365 return p;
366 }
367
368 static void fs_path_free(struct fs_path *p)
369 {
370 if (!p)
371 return;
372 if (p->buf != p->inline_buf)
373 kfree(p->buf);
374 kfree(p);
375 }
376
377 static int fs_path_len(struct fs_path *p)
378 {
379 return p->end - p->start;
380 }
381
382 static int fs_path_ensure_buf(struct fs_path *p, int len)
383 {
384 char *tmp_buf;
385 int path_len;
386 int old_buf_len;
387
388 len++;
389
390 if (p->buf_len >= len)
391 return 0;
392
393 if (len > PATH_MAX) {
394 WARN_ON(1);
395 return -ENOMEM;
396 }
397
398 path_len = p->end - p->start;
399 old_buf_len = p->buf_len;
400
401 /*
402 * First time the inline_buf does not suffice
403 */
404 if (p->buf == p->inline_buf) {
405 tmp_buf = kmalloc(len, GFP_KERNEL);
406 if (tmp_buf)
407 memcpy(tmp_buf, p->buf, old_buf_len);
408 } else {
409 tmp_buf = krealloc(p->buf, len, GFP_KERNEL);
410 }
411 if (!tmp_buf)
412 return -ENOMEM;
413 p->buf = tmp_buf;
414 /*
415 * The real size of the buffer is bigger, this will let the fast path
416 * happen most of the time
417 */
418 p->buf_len = ksize(p->buf);
419
420 if (p->reversed) {
421 tmp_buf = p->buf + old_buf_len - path_len - 1;
422 p->end = p->buf + p->buf_len - 1;
423 p->start = p->end - path_len;
424 memmove(p->start, tmp_buf, path_len + 1);
425 } else {
426 p->start = p->buf;
427 p->end = p->start + path_len;
428 }
429 return 0;
430 }
431
432 static int fs_path_prepare_for_add(struct fs_path *p, int name_len,
433 char **prepared)
434 {
435 int ret;
436 int new_len;
437
438 new_len = p->end - p->start + name_len;
439 if (p->start != p->end)
440 new_len++;
441 ret = fs_path_ensure_buf(p, new_len);
442 if (ret < 0)
443 goto out;
444
445 if (p->reversed) {
446 if (p->start != p->end)
447 *--p->start = '/';
448 p->start -= name_len;
449 *prepared = p->start;
450 } else {
451 if (p->start != p->end)
452 *p->end++ = '/';
453 *prepared = p->end;
454 p->end += name_len;
455 *p->end = 0;
456 }
457
458 out:
459 return ret;
460 }
461
462 static int fs_path_add(struct fs_path *p, const char *name, int name_len)
463 {
464 int ret;
465 char *prepared;
466
467 ret = fs_path_prepare_for_add(p, name_len, &prepared);
468 if (ret < 0)
469 goto out;
470 memcpy(prepared, name, name_len);
471
472 out:
473 return ret;
474 }
475
476 static int fs_path_add_path(struct fs_path *p, struct fs_path *p2)
477 {
478 int ret;
479 char *prepared;
480
481 ret = fs_path_prepare_for_add(p, p2->end - p2->start, &prepared);
482 if (ret < 0)
483 goto out;
484 memcpy(prepared, p2->start, p2->end - p2->start);
485
486 out:
487 return ret;
488 }
489
490 static int fs_path_add_from_extent_buffer(struct fs_path *p,
491 struct extent_buffer *eb,
492 unsigned long off, int len)
493 {
494 int ret;
495 char *prepared;
496
497 ret = fs_path_prepare_for_add(p, len, &prepared);
498 if (ret < 0)
499 goto out;
500
501 read_extent_buffer(eb, prepared, off, len);
502
503 out:
504 return ret;
505 }
506
507 static int fs_path_copy(struct fs_path *p, struct fs_path *from)
508 {
509 int ret;
510
511 p->reversed = from->reversed;
512 fs_path_reset(p);
513
514 ret = fs_path_add_path(p, from);
515
516 return ret;
517 }
518
519
520 static void fs_path_unreverse(struct fs_path *p)
521 {
522 char *tmp;
523 int len;
524
525 if (!p->reversed)
526 return;
527
528 tmp = p->start;
529 len = p->end - p->start;
530 p->start = p->buf;
531 p->end = p->start + len;
532 memmove(p->start, tmp, len + 1);
533 p->reversed = 0;
534 }
535
536 static struct btrfs_path *alloc_path_for_send(void)
537 {
538 struct btrfs_path *path;
539
540 path = btrfs_alloc_path();
541 if (!path)
542 return NULL;
543 path->search_commit_root = 1;
544 path->skip_locking = 1;
545 path->need_commit_sem = 1;
546 return path;
547 }
548
549 static int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off)
550 {
551 int ret;
552 u32 pos = 0;
553
554 while (pos < len) {
555 ret = kernel_write(filp, buf + pos, len - pos, off);
556 /* TODO handle that correctly */
557 /*if (ret == -ERESTARTSYS) {
558 continue;
559 }*/
560 if (ret < 0)
561 return ret;
562 if (ret == 0) {
563 return -EIO;
564 }
565 pos += ret;
566 }
567
568 return 0;
569 }
570
571 static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len)
572 {
573 struct btrfs_tlv_header *hdr;
574 int total_len = sizeof(*hdr) + len;
575 int left = sctx->send_max_size - sctx->send_size;
576
577 if (unlikely(left < total_len))
578 return -EOVERFLOW;
579
580 hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size);
581 put_unaligned_le16(attr, &hdr->tlv_type);
582 put_unaligned_le16(len, &hdr->tlv_len);
583 memcpy(hdr + 1, data, len);
584 sctx->send_size += total_len;
585
586 return 0;
587 }
588
589 #define TLV_PUT_DEFINE_INT(bits) \
590 static int tlv_put_u##bits(struct send_ctx *sctx, \
591 u##bits attr, u##bits value) \
592 { \
593 __le##bits __tmp = cpu_to_le##bits(value); \
594 return tlv_put(sctx, attr, &__tmp, sizeof(__tmp)); \
595 }
596
597 TLV_PUT_DEFINE_INT(64)
598
599 static int tlv_put_string(struct send_ctx *sctx, u16 attr,
600 const char *str, int len)
601 {
602 if (len == -1)
603 len = strlen(str);
604 return tlv_put(sctx, attr, str, len);
605 }
606
607 static int tlv_put_uuid(struct send_ctx *sctx, u16 attr,
608 const u8 *uuid)
609 {
610 return tlv_put(sctx, attr, uuid, BTRFS_UUID_SIZE);
611 }
612
613 static int tlv_put_btrfs_timespec(struct send_ctx *sctx, u16 attr,
614 struct extent_buffer *eb,
615 struct btrfs_timespec *ts)
616 {
617 struct btrfs_timespec bts;
618 read_extent_buffer(eb, &bts, (unsigned long)ts, sizeof(bts));
619 return tlv_put(sctx, attr, &bts, sizeof(bts));
620 }
621
622
623 #define TLV_PUT(sctx, attrtype, data, attrlen) \
624 do { \
625 ret = tlv_put(sctx, attrtype, data, attrlen); \
626 if (ret < 0) \
627 goto tlv_put_failure; \
628 } while (0)
629
630 #define TLV_PUT_INT(sctx, attrtype, bits, value) \
631 do { \
632 ret = tlv_put_u##bits(sctx, attrtype, value); \
633 if (ret < 0) \
634 goto tlv_put_failure; \
635 } while (0)
636
637 #define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data)
638 #define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data)
639 #define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data)
640 #define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data)
641 #define TLV_PUT_STRING(sctx, attrtype, str, len) \
642 do { \
643 ret = tlv_put_string(sctx, attrtype, str, len); \
644 if (ret < 0) \
645 goto tlv_put_failure; \
646 } while (0)
647 #define TLV_PUT_PATH(sctx, attrtype, p) \
648 do { \
649 ret = tlv_put_string(sctx, attrtype, p->start, \
650 p->end - p->start); \
651 if (ret < 0) \
652 goto tlv_put_failure; \
653 } while(0)
654 #define TLV_PUT_UUID(sctx, attrtype, uuid) \
655 do { \
656 ret = tlv_put_uuid(sctx, attrtype, uuid); \
657 if (ret < 0) \
658 goto tlv_put_failure; \
659 } while (0)
660 #define TLV_PUT_BTRFS_TIMESPEC(sctx, attrtype, eb, ts) \
661 do { \
662 ret = tlv_put_btrfs_timespec(sctx, attrtype, eb, ts); \
663 if (ret < 0) \
664 goto tlv_put_failure; \
665 } while (0)
666
667 static int send_header(struct send_ctx *sctx)
668 {
669 struct btrfs_stream_header hdr;
670
671 strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
672 hdr.version = cpu_to_le32(BTRFS_SEND_STREAM_VERSION);
673
674 return write_buf(sctx->send_filp, &hdr, sizeof(hdr),
675 &sctx->send_off);
676 }
677
678 /*
679 * For each command/item we want to send to userspace, we call this function.
680 */
681 static int begin_cmd(struct send_ctx *sctx, int cmd)
682 {
683 struct btrfs_cmd_header *hdr;
684
685 if (WARN_ON(!sctx->send_buf))
686 return -EINVAL;
687
688 BUG_ON(sctx->send_size);
689
690 sctx->send_size += sizeof(*hdr);
691 hdr = (struct btrfs_cmd_header *)sctx->send_buf;
692 put_unaligned_le16(cmd, &hdr->cmd);
693
694 return 0;
695 }
696
697 static int send_cmd(struct send_ctx *sctx)
698 {
699 int ret;
700 struct btrfs_cmd_header *hdr;
701 u32 crc;
702
703 hdr = (struct btrfs_cmd_header *)sctx->send_buf;
704 put_unaligned_le32(sctx->send_size - sizeof(*hdr), &hdr->len);
705 put_unaligned_le32(0, &hdr->crc);
706
707 crc = btrfs_crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
708 put_unaligned_le32(crc, &hdr->crc);
709
710 ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size,
711 &sctx->send_off);
712
713 sctx->total_send_size += sctx->send_size;
714 sctx->cmd_send_size[get_unaligned_le16(&hdr->cmd)] += sctx->send_size;
715 sctx->send_size = 0;
716
717 return ret;
718 }
719
720 /*
721 * Sends a move instruction to user space
722 */
723 static int send_rename(struct send_ctx *sctx,
724 struct fs_path *from, struct fs_path *to)
725 {
726 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
727 int ret;
728
729 btrfs_debug(fs_info, "send_rename %s -> %s", from->start, to->start);
730
731 ret = begin_cmd(sctx, BTRFS_SEND_C_RENAME);
732 if (ret < 0)
733 goto out;
734
735 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, from);
736 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_TO, to);
737
738 ret = send_cmd(sctx);
739
740 tlv_put_failure:
741 out:
742 return ret;
743 }
744
745 /*
746 * Sends a link instruction to user space
747 */
748 static int send_link(struct send_ctx *sctx,
749 struct fs_path *path, struct fs_path *lnk)
750 {
751 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
752 int ret;
753
754 btrfs_debug(fs_info, "send_link %s -> %s", path->start, lnk->start);
755
756 ret = begin_cmd(sctx, BTRFS_SEND_C_LINK);
757 if (ret < 0)
758 goto out;
759
760 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
761 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, lnk);
762
763 ret = send_cmd(sctx);
764
765 tlv_put_failure:
766 out:
767 return ret;
768 }
769
770 /*
771 * Sends an unlink instruction to user space
772 */
773 static int send_unlink(struct send_ctx *sctx, struct fs_path *path)
774 {
775 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
776 int ret;
777
778 btrfs_debug(fs_info, "send_unlink %s", path->start);
779
780 ret = begin_cmd(sctx, BTRFS_SEND_C_UNLINK);
781 if (ret < 0)
782 goto out;
783
784 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
785
786 ret = send_cmd(sctx);
787
788 tlv_put_failure:
789 out:
790 return ret;
791 }
792
793 /*
794 * Sends a rmdir instruction to user space
795 */
796 static int send_rmdir(struct send_ctx *sctx, struct fs_path *path)
797 {
798 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
799 int ret;
800
801 btrfs_debug(fs_info, "send_rmdir %s", path->start);
802
803 ret = begin_cmd(sctx, BTRFS_SEND_C_RMDIR);
804 if (ret < 0)
805 goto out;
806
807 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
808
809 ret = send_cmd(sctx);
810
811 tlv_put_failure:
812 out:
813 return ret;
814 }
815
816 /*
817 * Helper function to retrieve some fields from an inode item.
818 */
819 static int __get_inode_info(struct btrfs_root *root, struct btrfs_path *path,
820 u64 ino, u64 *size, u64 *gen, u64 *mode, u64 *uid,
821 u64 *gid, u64 *rdev)
822 {
823 int ret;
824 struct btrfs_inode_item *ii;
825 struct btrfs_key key;
826
827 key.objectid = ino;
828 key.type = BTRFS_INODE_ITEM_KEY;
829 key.offset = 0;
830 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
831 if (ret) {
832 if (ret > 0)
833 ret = -ENOENT;
834 return ret;
835 }
836
837 ii = btrfs_item_ptr(path->nodes[0], path->slots[0],
838 struct btrfs_inode_item);
839 if (size)
840 *size = btrfs_inode_size(path->nodes[0], ii);
841 if (gen)
842 *gen = btrfs_inode_generation(path->nodes[0], ii);
843 if (mode)
844 *mode = btrfs_inode_mode(path->nodes[0], ii);
845 if (uid)
846 *uid = btrfs_inode_uid(path->nodes[0], ii);
847 if (gid)
848 *gid = btrfs_inode_gid(path->nodes[0], ii);
849 if (rdev)
850 *rdev = btrfs_inode_rdev(path->nodes[0], ii);
851
852 return ret;
853 }
854
855 static int get_inode_info(struct btrfs_root *root,
856 u64 ino, u64 *size, u64 *gen,
857 u64 *mode, u64 *uid, u64 *gid,
858 u64 *rdev)
859 {
860 struct btrfs_path *path;
861 int ret;
862
863 path = alloc_path_for_send();
864 if (!path)
865 return -ENOMEM;
866 ret = __get_inode_info(root, path, ino, size, gen, mode, uid, gid,
867 rdev);
868 btrfs_free_path(path);
869 return ret;
870 }
871
872 typedef int (*iterate_inode_ref_t)(int num, u64 dir, int index,
873 struct fs_path *p,
874 void *ctx);
875
876 /*
877 * Helper function to iterate the entries in ONE btrfs_inode_ref or
878 * btrfs_inode_extref.
879 * The iterate callback may return a non zero value to stop iteration. This can
880 * be a negative value for error codes or 1 to simply stop it.
881 *
882 * path must point to the INODE_REF or INODE_EXTREF when called.
883 */
884 static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path,
885 struct btrfs_key *found_key, int resolve,
886 iterate_inode_ref_t iterate, void *ctx)
887 {
888 struct extent_buffer *eb = path->nodes[0];
889 struct btrfs_item *item;
890 struct btrfs_inode_ref *iref;
891 struct btrfs_inode_extref *extref;
892 struct btrfs_path *tmp_path;
893 struct fs_path *p;
894 u32 cur = 0;
895 u32 total;
896 int slot = path->slots[0];
897 u32 name_len;
898 char *start;
899 int ret = 0;
900 int num = 0;
901 int index;
902 u64 dir;
903 unsigned long name_off;
904 unsigned long elem_size;
905 unsigned long ptr;
906
907 p = fs_path_alloc_reversed();
908 if (!p)
909 return -ENOMEM;
910
911 tmp_path = alloc_path_for_send();
912 if (!tmp_path) {
913 fs_path_free(p);
914 return -ENOMEM;
915 }
916
917
918 if (found_key->type == BTRFS_INODE_REF_KEY) {
919 ptr = (unsigned long)btrfs_item_ptr(eb, slot,
920 struct btrfs_inode_ref);
921 item = btrfs_item_nr(slot);
922 total = btrfs_item_size(eb, item);
923 elem_size = sizeof(*iref);
924 } else {
925 ptr = btrfs_item_ptr_offset(eb, slot);
926 total = btrfs_item_size_nr(eb, slot);
927 elem_size = sizeof(*extref);
928 }
929
930 while (cur < total) {
931 fs_path_reset(p);
932
933 if (found_key->type == BTRFS_INODE_REF_KEY) {
934 iref = (struct btrfs_inode_ref *)(ptr + cur);
935 name_len = btrfs_inode_ref_name_len(eb, iref);
936 name_off = (unsigned long)(iref + 1);
937 index = btrfs_inode_ref_index(eb, iref);
938 dir = found_key->offset;
939 } else {
940 extref = (struct btrfs_inode_extref *)(ptr + cur);
941 name_len = btrfs_inode_extref_name_len(eb, extref);
942 name_off = (unsigned long)&extref->name;
943 index = btrfs_inode_extref_index(eb, extref);
944 dir = btrfs_inode_extref_parent(eb, extref);
945 }
946
947 if (resolve) {
948 start = btrfs_ref_to_path(root, tmp_path, name_len,
949 name_off, eb, dir,
950 p->buf, p->buf_len);
951 if (IS_ERR(start)) {
952 ret = PTR_ERR(start);
953 goto out;
954 }
955 if (start < p->buf) {
956 /* overflow , try again with larger buffer */
957 ret = fs_path_ensure_buf(p,
958 p->buf_len + p->buf - start);
959 if (ret < 0)
960 goto out;
961 start = btrfs_ref_to_path(root, tmp_path,
962 name_len, name_off,
963 eb, dir,
964 p->buf, p->buf_len);
965 if (IS_ERR(start)) {
966 ret = PTR_ERR(start);
967 goto out;
968 }
969 BUG_ON(start < p->buf);
970 }
971 p->start = start;
972 } else {
973 ret = fs_path_add_from_extent_buffer(p, eb, name_off,
974 name_len);
975 if (ret < 0)
976 goto out;
977 }
978
979 cur += elem_size + name_len;
980 ret = iterate(num, dir, index, p, ctx);
981 if (ret)
982 goto out;
983 num++;
984 }
985
986 out:
987 btrfs_free_path(tmp_path);
988 fs_path_free(p);
989 return ret;
990 }
991
992 typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key,
993 const char *name, int name_len,
994 const char *data, int data_len,
995 u8 type, void *ctx);
996
997 /*
998 * Helper function to iterate the entries in ONE btrfs_dir_item.
999 * The iterate callback may return a non zero value to stop iteration. This can
1000 * be a negative value for error codes or 1 to simply stop it.
1001 *
1002 * path must point to the dir item when called.
1003 */
1004 static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path,
1005 iterate_dir_item_t iterate, void *ctx)
1006 {
1007 int ret = 0;
1008 struct extent_buffer *eb;
1009 struct btrfs_item *item;
1010 struct btrfs_dir_item *di;
1011 struct btrfs_key di_key;
1012 char *buf = NULL;
1013 int buf_len;
1014 u32 name_len;
1015 u32 data_len;
1016 u32 cur;
1017 u32 len;
1018 u32 total;
1019 int slot;
1020 int num;
1021 u8 type;
1022
1023 /*
1024 * Start with a small buffer (1 page). If later we end up needing more
1025 * space, which can happen for xattrs on a fs with a leaf size greater
1026 * then the page size, attempt to increase the buffer. Typically xattr
1027 * values are small.
1028 */
1029 buf_len = PATH_MAX;
1030 buf = kmalloc(buf_len, GFP_KERNEL);
1031 if (!buf) {
1032 ret = -ENOMEM;
1033 goto out;
1034 }
1035
1036 eb = path->nodes[0];
1037 slot = path->slots[0];
1038 item = btrfs_item_nr(slot);
1039 di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
1040 cur = 0;
1041 len = 0;
1042 total = btrfs_item_size(eb, item);
1043
1044 num = 0;
1045 while (cur < total) {
1046 name_len = btrfs_dir_name_len(eb, di);
1047 data_len = btrfs_dir_data_len(eb, di);
1048 type = btrfs_dir_type(eb, di);
1049 btrfs_dir_item_key_to_cpu(eb, di, &di_key);
1050
1051 if (type == BTRFS_FT_XATTR) {
1052 if (name_len > XATTR_NAME_MAX) {
1053 ret = -ENAMETOOLONG;
1054 goto out;
1055 }
1056 if (name_len + data_len >
1057 BTRFS_MAX_XATTR_SIZE(root->fs_info)) {
1058 ret = -E2BIG;
1059 goto out;
1060 }
1061 } else {
1062 /*
1063 * Path too long
1064 */
1065 if (name_len + data_len > PATH_MAX) {
1066 ret = -ENAMETOOLONG;
1067 goto out;
1068 }
1069 }
1070
1071 if (name_len + data_len > buf_len) {
1072 buf_len = name_len + data_len;
1073 if (is_vmalloc_addr(buf)) {
1074 vfree(buf);
1075 buf = NULL;
1076 } else {
1077 char *tmp = krealloc(buf, buf_len,
1078 GFP_KERNEL | __GFP_NOWARN);
1079
1080 if (!tmp)
1081 kfree(buf);
1082 buf = tmp;
1083 }
1084 if (!buf) {
1085 buf = kvmalloc(buf_len, GFP_KERNEL);
1086 if (!buf) {
1087 ret = -ENOMEM;
1088 goto out;
1089 }
1090 }
1091 }
1092
1093 read_extent_buffer(eb, buf, (unsigned long)(di + 1),
1094 name_len + data_len);
1095
1096 len = sizeof(*di) + name_len + data_len;
1097 di = (struct btrfs_dir_item *)((char *)di + len);
1098 cur += len;
1099
1100 ret = iterate(num, &di_key, buf, name_len, buf + name_len,
1101 data_len, type, ctx);
1102 if (ret < 0)
1103 goto out;
1104 if (ret) {
1105 ret = 0;
1106 goto out;
1107 }
1108
1109 num++;
1110 }
1111
1112 out:
1113 kvfree(buf);
1114 return ret;
1115 }
1116
1117 static int __copy_first_ref(int num, u64 dir, int index,
1118 struct fs_path *p, void *ctx)
1119 {
1120 int ret;
1121 struct fs_path *pt = ctx;
1122
1123 ret = fs_path_copy(pt, p);
1124 if (ret < 0)
1125 return ret;
1126
1127 /* we want the first only */
1128 return 1;
1129 }
1130
1131 /*
1132 * Retrieve the first path of an inode. If an inode has more then one
1133 * ref/hardlink, this is ignored.
1134 */
1135 static int get_inode_path(struct btrfs_root *root,
1136 u64 ino, struct fs_path *path)
1137 {
1138 int ret;
1139 struct btrfs_key key, found_key;
1140 struct btrfs_path *p;
1141
1142 p = alloc_path_for_send();
1143 if (!p)
1144 return -ENOMEM;
1145
1146 fs_path_reset(path);
1147
1148 key.objectid = ino;
1149 key.type = BTRFS_INODE_REF_KEY;
1150 key.offset = 0;
1151
1152 ret = btrfs_search_slot_for_read(root, &key, p, 1, 0);
1153 if (ret < 0)
1154 goto out;
1155 if (ret) {
1156 ret = 1;
1157 goto out;
1158 }
1159 btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]);
1160 if (found_key.objectid != ino ||
1161 (found_key.type != BTRFS_INODE_REF_KEY &&
1162 found_key.type != BTRFS_INODE_EXTREF_KEY)) {
1163 ret = -ENOENT;
1164 goto out;
1165 }
1166
1167 ret = iterate_inode_ref(root, p, &found_key, 1,
1168 __copy_first_ref, path);
1169 if (ret < 0)
1170 goto out;
1171 ret = 0;
1172
1173 out:
1174 btrfs_free_path(p);
1175 return ret;
1176 }
1177
1178 struct backref_ctx {
1179 struct send_ctx *sctx;
1180
1181 /* number of total found references */
1182 u64 found;
1183
1184 /*
1185 * used for clones found in send_root. clones found behind cur_objectid
1186 * and cur_offset are not considered as allowed clones.
1187 */
1188 u64 cur_objectid;
1189 u64 cur_offset;
1190
1191 /* may be truncated in case it's the last extent in a file */
1192 u64 extent_len;
1193
1194 /* Just to check for bugs in backref resolving */
1195 int found_itself;
1196 };
1197
1198 static int __clone_root_cmp_bsearch(const void *key, const void *elt)
1199 {
1200 u64 root = (u64)(uintptr_t)key;
1201 struct clone_root *cr = (struct clone_root *)elt;
1202
1203 if (root < cr->root->root_key.objectid)
1204 return -1;
1205 if (root > cr->root->root_key.objectid)
1206 return 1;
1207 return 0;
1208 }
1209
1210 static int __clone_root_cmp_sort(const void *e1, const void *e2)
1211 {
1212 struct clone_root *cr1 = (struct clone_root *)e1;
1213 struct clone_root *cr2 = (struct clone_root *)e2;
1214
1215 if (cr1->root->root_key.objectid < cr2->root->root_key.objectid)
1216 return -1;
1217 if (cr1->root->root_key.objectid > cr2->root->root_key.objectid)
1218 return 1;
1219 return 0;
1220 }
1221
1222 /*
1223 * Called for every backref that is found for the current extent.
1224 * Results are collected in sctx->clone_roots->ino/offset/found_refs
1225 */
1226 static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_)
1227 {
1228 struct backref_ctx *bctx = ctx_;
1229 struct clone_root *found;
1230
1231 /* First check if the root is in the list of accepted clone sources */
1232 found = bsearch((void *)(uintptr_t)root, bctx->sctx->clone_roots,
1233 bctx->sctx->clone_roots_cnt,
1234 sizeof(struct clone_root),
1235 __clone_root_cmp_bsearch);
1236 if (!found)
1237 return 0;
1238
1239 if (found->root == bctx->sctx->send_root &&
1240 ino == bctx->cur_objectid &&
1241 offset == bctx->cur_offset) {
1242 bctx->found_itself = 1;
1243 }
1244
1245 /*
1246 * Make sure we don't consider clones from send_root that are
1247 * behind the current inode/offset.
1248 */
1249 if (found->root == bctx->sctx->send_root) {
1250 /*
1251 * If the source inode was not yet processed we can't issue a
1252 * clone operation, as the source extent does not exist yet at
1253 * the destination of the stream.
1254 */
1255 if (ino > bctx->cur_objectid)
1256 return 0;
1257 /*
1258 * We clone from the inode currently being sent as long as the
1259 * source extent is already processed, otherwise we could try
1260 * to clone from an extent that does not exist yet at the
1261 * destination of the stream.
1262 */
1263 if (ino == bctx->cur_objectid &&
1264 offset + bctx->extent_len >
1265 bctx->sctx->cur_inode_next_write_offset)
1266 return 0;
1267 }
1268
1269 bctx->found++;
1270 found->found_refs++;
1271 if (ino < found->ino) {
1272 found->ino = ino;
1273 found->offset = offset;
1274 } else if (found->ino == ino) {
1275 /*
1276 * same extent found more then once in the same file.
1277 */
1278 if (found->offset > offset + bctx->extent_len)
1279 found->offset = offset;
1280 }
1281
1282 return 0;
1283 }
1284
1285 /*
1286 * Given an inode, offset and extent item, it finds a good clone for a clone
1287 * instruction. Returns -ENOENT when none could be found. The function makes
1288 * sure that the returned clone is usable at the point where sending is at the
1289 * moment. This means, that no clones are accepted which lie behind the current
1290 * inode+offset.
1291 *
1292 * path must point to the extent item when called.
1293 */
1294 static int find_extent_clone(struct send_ctx *sctx,
1295 struct btrfs_path *path,
1296 u64 ino, u64 data_offset,
1297 u64 ino_size,
1298 struct clone_root **found)
1299 {
1300 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
1301 int ret;
1302 int extent_type;
1303 u64 logical;
1304 u64 disk_byte;
1305 u64 num_bytes;
1306 u64 extent_item_pos;
1307 u64 flags = 0;
1308 struct btrfs_file_extent_item *fi;
1309 struct extent_buffer *eb = path->nodes[0];
1310 struct backref_ctx *backref_ctx = NULL;
1311 struct clone_root *cur_clone_root;
1312 struct btrfs_key found_key;
1313 struct btrfs_path *tmp_path;
1314 struct btrfs_extent_item *ei;
1315 int compressed;
1316 u32 i;
1317
1318 tmp_path = alloc_path_for_send();
1319 if (!tmp_path)
1320 return -ENOMEM;
1321
1322 /* We only use this path under the commit sem */
1323 tmp_path->need_commit_sem = 0;
1324
1325 backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_KERNEL);
1326 if (!backref_ctx) {
1327 ret = -ENOMEM;
1328 goto out;
1329 }
1330
1331 if (data_offset >= ino_size) {
1332 /*
1333 * There may be extents that lie behind the file's size.
1334 * I at least had this in combination with snapshotting while
1335 * writing large files.
1336 */
1337 ret = 0;
1338 goto out;
1339 }
1340
1341 fi = btrfs_item_ptr(eb, path->slots[0],
1342 struct btrfs_file_extent_item);
1343 extent_type = btrfs_file_extent_type(eb, fi);
1344 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1345 ret = -ENOENT;
1346 goto out;
1347 }
1348 compressed = btrfs_file_extent_compression(eb, fi);
1349
1350 num_bytes = btrfs_file_extent_num_bytes(eb, fi);
1351 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
1352 if (disk_byte == 0) {
1353 ret = -ENOENT;
1354 goto out;
1355 }
1356 logical = disk_byte + btrfs_file_extent_offset(eb, fi);
1357
1358 down_read(&fs_info->commit_root_sem);
1359 ret = extent_from_logical(fs_info, disk_byte, tmp_path,
1360 &found_key, &flags);
1361 up_read(&fs_info->commit_root_sem);
1362
1363 if (ret < 0)
1364 goto out;
1365 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1366 ret = -EIO;
1367 goto out;
1368 }
1369
1370 ei = btrfs_item_ptr(tmp_path->nodes[0], tmp_path->slots[0],
1371 struct btrfs_extent_item);
1372 /*
1373 * Backreference walking (iterate_extent_inodes() below) is currently
1374 * too expensive when an extent has a large number of references, both
1375 * in time spent and used memory. So for now just fallback to write
1376 * operations instead of clone operations when an extent has more than
1377 * a certain amount of references.
1378 */
1379 if (btrfs_extent_refs(tmp_path->nodes[0], ei) > SEND_MAX_EXTENT_REFS) {
1380 ret = -ENOENT;
1381 goto out;
1382 }
1383 btrfs_release_path(tmp_path);
1384
1385 /*
1386 * Setup the clone roots.
1387 */
1388 for (i = 0; i < sctx->clone_roots_cnt; i++) {
1389 cur_clone_root = sctx->clone_roots + i;
1390 cur_clone_root->ino = (u64)-1;
1391 cur_clone_root->offset = 0;
1392 cur_clone_root->found_refs = 0;
1393 }
1394
1395 backref_ctx->sctx = sctx;
1396 backref_ctx->found = 0;
1397 backref_ctx->cur_objectid = ino;
1398 backref_ctx->cur_offset = data_offset;
1399 backref_ctx->found_itself = 0;
1400 backref_ctx->extent_len = num_bytes;
1401
1402 /*
1403 * The last extent of a file may be too large due to page alignment.
1404 * We need to adjust extent_len in this case so that the checks in
1405 * __iterate_backrefs work.
1406 */
1407 if (data_offset + num_bytes >= ino_size)
1408 backref_ctx->extent_len = ino_size - data_offset;
1409
1410 /*
1411 * Now collect all backrefs.
1412 */
1413 if (compressed == BTRFS_COMPRESS_NONE)
1414 extent_item_pos = logical - found_key.objectid;
1415 else
1416 extent_item_pos = 0;
1417 ret = iterate_extent_inodes(fs_info, found_key.objectid,
1418 extent_item_pos, 1, __iterate_backrefs,
1419 backref_ctx, false);
1420
1421 if (ret < 0)
1422 goto out;
1423
1424 if (!backref_ctx->found_itself) {
1425 /* found a bug in backref code? */
1426 ret = -EIO;
1427 btrfs_err(fs_info,
1428 "did not find backref in send_root. inode=%llu, offset=%llu, disk_byte=%llu found extent=%llu",
1429 ino, data_offset, disk_byte, found_key.objectid);
1430 goto out;
1431 }
1432
1433 btrfs_debug(fs_info,
1434 "find_extent_clone: data_offset=%llu, ino=%llu, num_bytes=%llu, logical=%llu",
1435 data_offset, ino, num_bytes, logical);
1436
1437 if (!backref_ctx->found)
1438 btrfs_debug(fs_info, "no clones found");
1439
1440 cur_clone_root = NULL;
1441 for (i = 0; i < sctx->clone_roots_cnt; i++) {
1442 if (sctx->clone_roots[i].found_refs) {
1443 if (!cur_clone_root)
1444 cur_clone_root = sctx->clone_roots + i;
1445 else if (sctx->clone_roots[i].root == sctx->send_root)
1446 /* prefer clones from send_root over others */
1447 cur_clone_root = sctx->clone_roots + i;
1448 }
1449
1450 }
1451
1452 if (cur_clone_root) {
1453 *found = cur_clone_root;
1454 ret = 0;
1455 } else {
1456 ret = -ENOENT;
1457 }
1458
1459 out:
1460 btrfs_free_path(tmp_path);
1461 kfree(backref_ctx);
1462 return ret;
1463 }
1464
1465 static int read_symlink(struct btrfs_root *root,
1466 u64 ino,
1467 struct fs_path *dest)
1468 {
1469 int ret;
1470 struct btrfs_path *path;
1471 struct btrfs_key key;
1472 struct btrfs_file_extent_item *ei;
1473 u8 type;
1474 u8 compression;
1475 unsigned long off;
1476 int len;
1477
1478 path = alloc_path_for_send();
1479 if (!path)
1480 return -ENOMEM;
1481
1482 key.objectid = ino;
1483 key.type = BTRFS_EXTENT_DATA_KEY;
1484 key.offset = 0;
1485 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1486 if (ret < 0)
1487 goto out;
1488 if (ret) {
1489 /*
1490 * An empty symlink inode. Can happen in rare error paths when
1491 * creating a symlink (transaction committed before the inode
1492 * eviction handler removed the symlink inode items and a crash
1493 * happened in between or the subvol was snapshoted in between).
1494 * Print an informative message to dmesg/syslog so that the user
1495 * can delete the symlink.
1496 */
1497 btrfs_err(root->fs_info,
1498 "Found empty symlink inode %llu at root %llu",
1499 ino, root->root_key.objectid);
1500 ret = -EIO;
1501 goto out;
1502 }
1503
1504 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
1505 struct btrfs_file_extent_item);
1506 type = btrfs_file_extent_type(path->nodes[0], ei);
1507 compression = btrfs_file_extent_compression(path->nodes[0], ei);
1508 BUG_ON(type != BTRFS_FILE_EXTENT_INLINE);
1509 BUG_ON(compression);
1510
1511 off = btrfs_file_extent_inline_start(ei);
1512 len = btrfs_file_extent_ram_bytes(path->nodes[0], ei);
1513
1514 ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len);
1515
1516 out:
1517 btrfs_free_path(path);
1518 return ret;
1519 }
1520
1521 /*
1522 * Helper function to generate a file name that is unique in the root of
1523 * send_root and parent_root. This is used to generate names for orphan inodes.
1524 */
1525 static int gen_unique_name(struct send_ctx *sctx,
1526 u64 ino, u64 gen,
1527 struct fs_path *dest)
1528 {
1529 int ret = 0;
1530 struct btrfs_path *path;
1531 struct btrfs_dir_item *di;
1532 char tmp[64];
1533 int len;
1534 u64 idx = 0;
1535
1536 path = alloc_path_for_send();
1537 if (!path)
1538 return -ENOMEM;
1539
1540 while (1) {
1541 len = snprintf(tmp, sizeof(tmp), "o%llu-%llu-%llu",
1542 ino, gen, idx);
1543 ASSERT(len < sizeof(tmp));
1544
1545 di = btrfs_lookup_dir_item(NULL, sctx->send_root,
1546 path, BTRFS_FIRST_FREE_OBJECTID,
1547 tmp, strlen(tmp), 0);
1548 btrfs_release_path(path);
1549 if (IS_ERR(di)) {
1550 ret = PTR_ERR(di);
1551 goto out;
1552 }
1553 if (di) {
1554 /* not unique, try again */
1555 idx++;
1556 continue;
1557 }
1558
1559 if (!sctx->parent_root) {
1560 /* unique */
1561 ret = 0;
1562 break;
1563 }
1564
1565 di = btrfs_lookup_dir_item(NULL, sctx->parent_root,
1566 path, BTRFS_FIRST_FREE_OBJECTID,
1567 tmp, strlen(tmp), 0);
1568 btrfs_release_path(path);
1569 if (IS_ERR(di)) {
1570 ret = PTR_ERR(di);
1571 goto out;
1572 }
1573 if (di) {
1574 /* not unique, try again */
1575 idx++;
1576 continue;
1577 }
1578 /* unique */
1579 break;
1580 }
1581
1582 ret = fs_path_add(dest, tmp, strlen(tmp));
1583
1584 out:
1585 btrfs_free_path(path);
1586 return ret;
1587 }
1588
1589 enum inode_state {
1590 inode_state_no_change,
1591 inode_state_will_create,
1592 inode_state_did_create,
1593 inode_state_will_delete,
1594 inode_state_did_delete,
1595 };
1596
1597 static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen)
1598 {
1599 int ret;
1600 int left_ret;
1601 int right_ret;
1602 u64 left_gen;
1603 u64 right_gen;
1604
1605 ret = get_inode_info(sctx->send_root, ino, NULL, &left_gen, NULL, NULL,
1606 NULL, NULL);
1607 if (ret < 0 && ret != -ENOENT)
1608 goto out;
1609 left_ret = ret;
1610
1611 if (!sctx->parent_root) {
1612 right_ret = -ENOENT;
1613 } else {
1614 ret = get_inode_info(sctx->parent_root, ino, NULL, &right_gen,
1615 NULL, NULL, NULL, NULL);
1616 if (ret < 0 && ret != -ENOENT)
1617 goto out;
1618 right_ret = ret;
1619 }
1620
1621 if (!left_ret && !right_ret) {
1622 if (left_gen == gen && right_gen == gen) {
1623 ret = inode_state_no_change;
1624 } else if (left_gen == gen) {
1625 if (ino < sctx->send_progress)
1626 ret = inode_state_did_create;
1627 else
1628 ret = inode_state_will_create;
1629 } else if (right_gen == gen) {
1630 if (ino < sctx->send_progress)
1631 ret = inode_state_did_delete;
1632 else
1633 ret = inode_state_will_delete;
1634 } else {
1635 ret = -ENOENT;
1636 }
1637 } else if (!left_ret) {
1638 if (left_gen == gen) {
1639 if (ino < sctx->send_progress)
1640 ret = inode_state_did_create;
1641 else
1642 ret = inode_state_will_create;
1643 } else {
1644 ret = -ENOENT;
1645 }
1646 } else if (!right_ret) {
1647 if (right_gen == gen) {
1648 if (ino < sctx->send_progress)
1649 ret = inode_state_did_delete;
1650 else
1651 ret = inode_state_will_delete;
1652 } else {
1653 ret = -ENOENT;
1654 }
1655 } else {
1656 ret = -ENOENT;
1657 }
1658
1659 out:
1660 return ret;
1661 }
1662
1663 static int is_inode_existent(struct send_ctx *sctx, u64 ino, u64 gen)
1664 {
1665 int ret;
1666
1667 if (ino == BTRFS_FIRST_FREE_OBJECTID)
1668 return 1;
1669
1670 ret = get_cur_inode_state(sctx, ino, gen);
1671 if (ret < 0)
1672 goto out;
1673
1674 if (ret == inode_state_no_change ||
1675 ret == inode_state_did_create ||
1676 ret == inode_state_will_delete)
1677 ret = 1;
1678 else
1679 ret = 0;
1680
1681 out:
1682 return ret;
1683 }
1684
1685 /*
1686 * Helper function to lookup a dir item in a dir.
1687 */
1688 static int lookup_dir_item_inode(struct btrfs_root *root,
1689 u64 dir, const char *name, int name_len,
1690 u64 *found_inode,
1691 u8 *found_type)
1692 {
1693 int ret = 0;
1694 struct btrfs_dir_item *di;
1695 struct btrfs_key key;
1696 struct btrfs_path *path;
1697
1698 path = alloc_path_for_send();
1699 if (!path)
1700 return -ENOMEM;
1701
1702 di = btrfs_lookup_dir_item(NULL, root, path,
1703 dir, name, name_len, 0);
1704 if (IS_ERR_OR_NULL(di)) {
1705 ret = di ? PTR_ERR(di) : -ENOENT;
1706 goto out;
1707 }
1708 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
1709 if (key.type == BTRFS_ROOT_ITEM_KEY) {
1710 ret = -ENOENT;
1711 goto out;
1712 }
1713 *found_inode = key.objectid;
1714 *found_type = btrfs_dir_type(path->nodes[0], di);
1715
1716 out:
1717 btrfs_free_path(path);
1718 return ret;
1719 }
1720
1721 /*
1722 * Looks up the first btrfs_inode_ref of a given ino. It returns the parent dir,
1723 * generation of the parent dir and the name of the dir entry.
1724 */
1725 static int get_first_ref(struct btrfs_root *root, u64 ino,
1726 u64 *dir, u64 *dir_gen, struct fs_path *name)
1727 {
1728 int ret;
1729 struct btrfs_key key;
1730 struct btrfs_key found_key;
1731 struct btrfs_path *path;
1732 int len;
1733 u64 parent_dir;
1734
1735 path = alloc_path_for_send();
1736 if (!path)
1737 return -ENOMEM;
1738
1739 key.objectid = ino;
1740 key.type = BTRFS_INODE_REF_KEY;
1741 key.offset = 0;
1742
1743 ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
1744 if (ret < 0)
1745 goto out;
1746 if (!ret)
1747 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1748 path->slots[0]);
1749 if (ret || found_key.objectid != ino ||
1750 (found_key.type != BTRFS_INODE_REF_KEY &&
1751 found_key.type != BTRFS_INODE_EXTREF_KEY)) {
1752 ret = -ENOENT;
1753 goto out;
1754 }
1755
1756 if (found_key.type == BTRFS_INODE_REF_KEY) {
1757 struct btrfs_inode_ref *iref;
1758 iref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1759 struct btrfs_inode_ref);
1760 len = btrfs_inode_ref_name_len(path->nodes[0], iref);
1761 ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
1762 (unsigned long)(iref + 1),
1763 len);
1764 parent_dir = found_key.offset;
1765 } else {
1766 struct btrfs_inode_extref *extref;
1767 extref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1768 struct btrfs_inode_extref);
1769 len = btrfs_inode_extref_name_len(path->nodes[0], extref);
1770 ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
1771 (unsigned long)&extref->name, len);
1772 parent_dir = btrfs_inode_extref_parent(path->nodes[0], extref);
1773 }
1774 if (ret < 0)
1775 goto out;
1776 btrfs_release_path(path);
1777
1778 if (dir_gen) {
1779 ret = get_inode_info(root, parent_dir, NULL, dir_gen, NULL,
1780 NULL, NULL, NULL);
1781 if (ret < 0)
1782 goto out;
1783 }
1784
1785 *dir = parent_dir;
1786
1787 out:
1788 btrfs_free_path(path);
1789 return ret;
1790 }
1791
1792 static int is_first_ref(struct btrfs_root *root,
1793 u64 ino, u64 dir,
1794 const char *name, int name_len)
1795 {
1796 int ret;
1797 struct fs_path *tmp_name;
1798 u64 tmp_dir;
1799
1800 tmp_name = fs_path_alloc();
1801 if (!tmp_name)
1802 return -ENOMEM;
1803
1804 ret = get_first_ref(root, ino, &tmp_dir, NULL, tmp_name);
1805 if (ret < 0)
1806 goto out;
1807
1808 if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) {
1809 ret = 0;
1810 goto out;
1811 }
1812
1813 ret = !memcmp(tmp_name->start, name, name_len);
1814
1815 out:
1816 fs_path_free(tmp_name);
1817 return ret;
1818 }
1819
1820 /*
1821 * Used by process_recorded_refs to determine if a new ref would overwrite an
1822 * already existing ref. In case it detects an overwrite, it returns the
1823 * inode/gen in who_ino/who_gen.
1824 * When an overwrite is detected, process_recorded_refs does proper orphanizing
1825 * to make sure later references to the overwritten inode are possible.
1826 * Orphanizing is however only required for the first ref of an inode.
1827 * process_recorded_refs does an additional is_first_ref check to see if
1828 * orphanizing is really required.
1829 */
1830 static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
1831 const char *name, int name_len,
1832 u64 *who_ino, u64 *who_gen, u64 *who_mode)
1833 {
1834 int ret = 0;
1835 u64 gen;
1836 u64 other_inode = 0;
1837 u8 other_type = 0;
1838
1839 if (!sctx->parent_root)
1840 goto out;
1841
1842 ret = is_inode_existent(sctx, dir, dir_gen);
1843 if (ret <= 0)
1844 goto out;
1845
1846 /*
1847 * If we have a parent root we need to verify that the parent dir was
1848 * not deleted and then re-created, if it was then we have no overwrite
1849 * and we can just unlink this entry.
1850 */
1851 if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID) {
1852 ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL,
1853 NULL, NULL, NULL);
1854 if (ret < 0 && ret != -ENOENT)
1855 goto out;
1856 if (ret) {
1857 ret = 0;
1858 goto out;
1859 }
1860 if (gen != dir_gen)
1861 goto out;
1862 }
1863
1864 ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
1865 &other_inode, &other_type);
1866 if (ret < 0 && ret != -ENOENT)
1867 goto out;
1868 if (ret) {
1869 ret = 0;
1870 goto out;
1871 }
1872
1873 /*
1874 * Check if the overwritten ref was already processed. If yes, the ref
1875 * was already unlinked/moved, so we can safely assume that we will not
1876 * overwrite anything at this point in time.
1877 */
1878 if (other_inode > sctx->send_progress ||
1879 is_waiting_for_move(sctx, other_inode)) {
1880 ret = get_inode_info(sctx->parent_root, other_inode, NULL,
1881 who_gen, who_mode, NULL, NULL, NULL);
1882 if (ret < 0)
1883 goto out;
1884
1885 ret = 1;
1886 *who_ino = other_inode;
1887 } else {
1888 ret = 0;
1889 }
1890
1891 out:
1892 return ret;
1893 }
1894
1895 /*
1896 * Checks if the ref was overwritten by an already processed inode. This is
1897 * used by __get_cur_name_and_parent to find out if the ref was orphanized and
1898 * thus the orphan name needs be used.
1899 * process_recorded_refs also uses it to avoid unlinking of refs that were
1900 * overwritten.
1901 */
1902 static int did_overwrite_ref(struct send_ctx *sctx,
1903 u64 dir, u64 dir_gen,
1904 u64 ino, u64 ino_gen,
1905 const char *name, int name_len)
1906 {
1907 int ret = 0;
1908 u64 gen;
1909 u64 ow_inode;
1910 u8 other_type;
1911
1912 if (!sctx->parent_root)
1913 goto out;
1914
1915 ret = is_inode_existent(sctx, dir, dir_gen);
1916 if (ret <= 0)
1917 goto out;
1918
1919 if (dir != BTRFS_FIRST_FREE_OBJECTID) {
1920 ret = get_inode_info(sctx->send_root, dir, NULL, &gen, NULL,
1921 NULL, NULL, NULL);
1922 if (ret < 0 && ret != -ENOENT)
1923 goto out;
1924 if (ret) {
1925 ret = 0;
1926 goto out;
1927 }
1928 if (gen != dir_gen)
1929 goto out;
1930 }
1931
1932 /* check if the ref was overwritten by another ref */
1933 ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
1934 &ow_inode, &other_type);
1935 if (ret < 0 && ret != -ENOENT)
1936 goto out;
1937 if (ret) {
1938 /* was never and will never be overwritten */
1939 ret = 0;
1940 goto out;
1941 }
1942
1943 ret = get_inode_info(sctx->send_root, ow_inode, NULL, &gen, NULL, NULL,
1944 NULL, NULL);
1945 if (ret < 0)
1946 goto out;
1947
1948 if (ow_inode == ino && gen == ino_gen) {
1949 ret = 0;
1950 goto out;
1951 }
1952
1953 /*
1954 * We know that it is or will be overwritten. Check this now.
1955 * The current inode being processed might have been the one that caused
1956 * inode 'ino' to be orphanized, therefore check if ow_inode matches
1957 * the current inode being processed.
1958 */
1959 if ((ow_inode < sctx->send_progress) ||
1960 (ino != sctx->cur_ino && ow_inode == sctx->cur_ino &&
1961 gen == sctx->cur_inode_gen))
1962 ret = 1;
1963 else
1964 ret = 0;
1965
1966 out:
1967 return ret;
1968 }
1969
1970 /*
1971 * Same as did_overwrite_ref, but also checks if it is the first ref of an inode
1972 * that got overwritten. This is used by process_recorded_refs to determine
1973 * if it has to use the path as returned by get_cur_path or the orphan name.
1974 */
1975 static int did_overwrite_first_ref(struct send_ctx *sctx, u64 ino, u64 gen)
1976 {
1977 int ret = 0;
1978 struct fs_path *name = NULL;
1979 u64 dir;
1980 u64 dir_gen;
1981
1982 if (!sctx->parent_root)
1983 goto out;
1984
1985 name = fs_path_alloc();
1986 if (!name)
1987 return -ENOMEM;
1988
1989 ret = get_first_ref(sctx->parent_root, ino, &dir, &dir_gen, name);
1990 if (ret < 0)
1991 goto out;
1992
1993 ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen,
1994 name->start, fs_path_len(name));
1995
1996 out:
1997 fs_path_free(name);
1998 return ret;
1999 }
2000
2001 /*
2002 * Insert a name cache entry. On 32bit kernels the radix tree index is 32bit,
2003 * so we need to do some special handling in case we have clashes. This function
2004 * takes care of this with the help of name_cache_entry::radix_list.
2005 * In case of error, nce is kfreed.
2006 */
2007 static int name_cache_insert(struct send_ctx *sctx,
2008 struct name_cache_entry *nce)
2009 {
2010 int ret = 0;
2011 struct list_head *nce_head;
2012
2013 nce_head = radix_tree_lookup(&sctx->name_cache,
2014 (unsigned long)nce->ino);
2015 if (!nce_head) {
2016 nce_head = kmalloc(sizeof(*nce_head), GFP_KERNEL);
2017 if (!nce_head) {
2018 kfree(nce);
2019 return -ENOMEM;
2020 }
2021 INIT_LIST_HEAD(nce_head);
2022
2023 ret = radix_tree_insert(&sctx->name_cache, nce->ino, nce_head);
2024 if (ret < 0) {
2025 kfree(nce_head);
2026 kfree(nce);
2027 return ret;
2028 }
2029 }
2030 list_add_tail(&nce->radix_list, nce_head);
2031 list_add_tail(&nce->list, &sctx->name_cache_list);
2032 sctx->name_cache_size++;
2033
2034 return ret;
2035 }
2036
2037 static void name_cache_delete(struct send_ctx *sctx,
2038 struct name_cache_entry *nce)
2039 {
2040 struct list_head *nce_head;
2041
2042 nce_head = radix_tree_lookup(&sctx->name_cache,
2043 (unsigned long)nce->ino);
2044 if (!nce_head) {
2045 btrfs_err(sctx->send_root->fs_info,
2046 "name_cache_delete lookup failed ino %llu cache size %d, leaking memory",
2047 nce->ino, sctx->name_cache_size);
2048 }
2049
2050 list_del(&nce->radix_list);
2051 list_del(&nce->list);
2052 sctx->name_cache_size--;
2053
2054 /*
2055 * We may not get to the final release of nce_head if the lookup fails
2056 */
2057 if (nce_head && list_empty(nce_head)) {
2058 radix_tree_delete(&sctx->name_cache, (unsigned long)nce->ino);
2059 kfree(nce_head);
2060 }
2061 }
2062
2063 static struct name_cache_entry *name_cache_search(struct send_ctx *sctx,
2064 u64 ino, u64 gen)
2065 {
2066 struct list_head *nce_head;
2067 struct name_cache_entry *cur;
2068
2069 nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)ino);
2070 if (!nce_head)
2071 return NULL;
2072
2073 list_for_each_entry(cur, nce_head, radix_list) {
2074 if (cur->ino == ino && cur->gen == gen)
2075 return cur;
2076 }
2077 return NULL;
2078 }
2079
2080 /*
2081 * Removes the entry from the list and adds it back to the end. This marks the
2082 * entry as recently used so that name_cache_clean_unused does not remove it.
2083 */
2084 static void name_cache_used(struct send_ctx *sctx, struct name_cache_entry *nce)
2085 {
2086 list_del(&nce->list);
2087 list_add_tail(&nce->list, &sctx->name_cache_list);
2088 }
2089
2090 /*
2091 * Remove some entries from the beginning of name_cache_list.
2092 */
2093 static void name_cache_clean_unused(struct send_ctx *sctx)
2094 {
2095 struct name_cache_entry *nce;
2096
2097 if (sctx->name_cache_size < SEND_CTX_NAME_CACHE_CLEAN_SIZE)
2098 return;
2099
2100 while (sctx->name_cache_size > SEND_CTX_MAX_NAME_CACHE_SIZE) {
2101 nce = list_entry(sctx->name_cache_list.next,
2102 struct name_cache_entry, list);
2103 name_cache_delete(sctx, nce);
2104 kfree(nce);
2105 }
2106 }
2107
2108 static void name_cache_free(struct send_ctx *sctx)
2109 {
2110 struct name_cache_entry *nce;
2111
2112 while (!list_empty(&sctx->name_cache_list)) {
2113 nce = list_entry(sctx->name_cache_list.next,
2114 struct name_cache_entry, list);
2115 name_cache_delete(sctx, nce);
2116 kfree(nce);
2117 }
2118 }
2119
2120 /*
2121 * Used by get_cur_path for each ref up to the root.
2122 * Returns 0 if it succeeded.
2123 * Returns 1 if the inode is not existent or got overwritten. In that case, the
2124 * name is an orphan name. This instructs get_cur_path to stop iterating. If 1
2125 * is returned, parent_ino/parent_gen are not guaranteed to be valid.
2126 * Returns <0 in case of error.
2127 */
2128 static int __get_cur_name_and_parent(struct send_ctx *sctx,
2129 u64 ino, u64 gen,
2130 u64 *parent_ino,
2131 u64 *parent_gen,
2132 struct fs_path *dest)
2133 {
2134 int ret;
2135 int nce_ret;
2136 struct name_cache_entry *nce = NULL;
2137
2138 /*
2139 * First check if we already did a call to this function with the same
2140 * ino/gen. If yes, check if the cache entry is still up-to-date. If yes
2141 * return the cached result.
2142 */
2143 nce = name_cache_search(sctx, ino, gen);
2144 if (nce) {
2145 if (ino < sctx->send_progress && nce->need_later_update) {
2146 name_cache_delete(sctx, nce);
2147 kfree(nce);
2148 nce = NULL;
2149 } else {
2150 name_cache_used(sctx, nce);
2151 *parent_ino = nce->parent_ino;
2152 *parent_gen = nce->parent_gen;
2153 ret = fs_path_add(dest, nce->name, nce->name_len);
2154 if (ret < 0)
2155 goto out;
2156 ret = nce->ret;
2157 goto out;
2158 }
2159 }
2160
2161 /*
2162 * If the inode is not existent yet, add the orphan name and return 1.
2163 * This should only happen for the parent dir that we determine in
2164 * __record_new_ref
2165 */
2166 ret = is_inode_existent(sctx, ino, gen);
2167 if (ret < 0)
2168 goto out;
2169
2170 if (!ret) {
2171 ret = gen_unique_name(sctx, ino, gen, dest);
2172 if (ret < 0)
2173 goto out;
2174 ret = 1;
2175 goto out_cache;
2176 }
2177
2178 /*
2179 * Depending on whether the inode was already processed or not, use
2180 * send_root or parent_root for ref lookup.
2181 */
2182 if (ino < sctx->send_progress)
2183 ret = get_first_ref(sctx->send_root, ino,
2184 parent_ino, parent_gen, dest);
2185 else
2186 ret = get_first_ref(sctx->parent_root, ino,
2187 parent_ino, parent_gen, dest);
2188 if (ret < 0)
2189 goto out;
2190
2191 /*
2192 * Check if the ref was overwritten by an inode's ref that was processed
2193 * earlier. If yes, treat as orphan and return 1.
2194 */
2195 ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen,
2196 dest->start, dest->end - dest->start);
2197 if (ret < 0)
2198 goto out;
2199 if (ret) {
2200 fs_path_reset(dest);
2201 ret = gen_unique_name(sctx, ino, gen, dest);
2202 if (ret < 0)
2203 goto out;
2204 ret = 1;
2205 }
2206
2207 out_cache:
2208 /*
2209 * Store the result of the lookup in the name cache.
2210 */
2211 nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_KERNEL);
2212 if (!nce) {
2213 ret = -ENOMEM;
2214 goto out;
2215 }
2216
2217 nce->ino = ino;
2218 nce->gen = gen;
2219 nce->parent_ino = *parent_ino;
2220 nce->parent_gen = *parent_gen;
2221 nce->name_len = fs_path_len(dest);
2222 nce->ret = ret;
2223 strcpy(nce->name, dest->start);
2224
2225 if (ino < sctx->send_progress)
2226 nce->need_later_update = 0;
2227 else
2228 nce->need_later_update = 1;
2229
2230 nce_ret = name_cache_insert(sctx, nce);
2231 if (nce_ret < 0)
2232 ret = nce_ret;
2233 name_cache_clean_unused(sctx);
2234
2235 out:
2236 return ret;
2237 }
2238
2239 /*
2240 * Magic happens here. This function returns the first ref to an inode as it
2241 * would look like while receiving the stream at this point in time.
2242 * We walk the path up to the root. For every inode in between, we check if it
2243 * was already processed/sent. If yes, we continue with the parent as found
2244 * in send_root. If not, we continue with the parent as found in parent_root.
2245 * If we encounter an inode that was deleted at this point in time, we use the
2246 * inodes "orphan" name instead of the real name and stop. Same with new inodes
2247 * that were not created yet and overwritten inodes/refs.
2248 *
2249 * When do we have orphan inodes:
2250 * 1. When an inode is freshly created and thus no valid refs are available yet
2251 * 2. When a directory lost all it's refs (deleted) but still has dir items
2252 * inside which were not processed yet (pending for move/delete). If anyone
2253 * tried to get the path to the dir items, it would get a path inside that
2254 * orphan directory.
2255 * 3. When an inode is moved around or gets new links, it may overwrite the ref
2256 * of an unprocessed inode. If in that case the first ref would be
2257 * overwritten, the overwritten inode gets "orphanized". Later when we
2258 * process this overwritten inode, it is restored at a new place by moving
2259 * the orphan inode.
2260 *
2261 * sctx->send_progress tells this function at which point in time receiving
2262 * would be.
2263 */
2264 static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
2265 struct fs_path *dest)
2266 {
2267 int ret = 0;
2268 struct fs_path *name = NULL;
2269 u64 parent_inode = 0;
2270 u64 parent_gen = 0;
2271 int stop = 0;
2272
2273 name = fs_path_alloc();
2274 if (!name) {
2275 ret = -ENOMEM;
2276 goto out;
2277 }
2278
2279 dest->reversed = 1;
2280 fs_path_reset(dest);
2281
2282 while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) {
2283 struct waiting_dir_move *wdm;
2284
2285 fs_path_reset(name);
2286
2287 if (is_waiting_for_rm(sctx, ino, gen)) {
2288 ret = gen_unique_name(sctx, ino, gen, name);
2289 if (ret < 0)
2290 goto out;
2291 ret = fs_path_add_path(dest, name);
2292 break;
2293 }
2294
2295 wdm = get_waiting_dir_move(sctx, ino);
2296 if (wdm && wdm->orphanized) {
2297 ret = gen_unique_name(sctx, ino, gen, name);
2298 stop = 1;
2299 } else if (wdm) {
2300 ret = get_first_ref(sctx->parent_root, ino,
2301 &parent_inode, &parent_gen, name);
2302 } else {
2303 ret = __get_cur_name_and_parent(sctx, ino, gen,
2304 &parent_inode,
2305 &parent_gen, name);
2306 if (ret)
2307 stop = 1;
2308 }
2309
2310 if (ret < 0)
2311 goto out;
2312
2313 ret = fs_path_add_path(dest, name);
2314 if (ret < 0)
2315 goto out;
2316
2317 ino = parent_inode;
2318 gen = parent_gen;
2319 }
2320
2321 out:
2322 fs_path_free(name);
2323 if (!ret)
2324 fs_path_unreverse(dest);
2325 return ret;
2326 }
2327
2328 /*
2329 * Sends a BTRFS_SEND_C_SUBVOL command/item to userspace
2330 */
2331 static int send_subvol_begin(struct send_ctx *sctx)
2332 {
2333 int ret;
2334 struct btrfs_root *send_root = sctx->send_root;
2335 struct btrfs_root *parent_root = sctx->parent_root;
2336 struct btrfs_path *path;
2337 struct btrfs_key key;
2338 struct btrfs_root_ref *ref;
2339 struct extent_buffer *leaf;
2340 char *name = NULL;
2341 int namelen;
2342
2343 path = btrfs_alloc_path();
2344 if (!path)
2345 return -ENOMEM;
2346
2347 name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL);
2348 if (!name) {
2349 btrfs_free_path(path);
2350 return -ENOMEM;
2351 }
2352
2353 key.objectid = send_root->root_key.objectid;
2354 key.type = BTRFS_ROOT_BACKREF_KEY;
2355 key.offset = 0;
2356
2357 ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root,
2358 &key, path, 1, 0);
2359 if (ret < 0)
2360 goto out;
2361 if (ret) {
2362 ret = -ENOENT;
2363 goto out;
2364 }
2365
2366 leaf = path->nodes[0];
2367 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2368 if (key.type != BTRFS_ROOT_BACKREF_KEY ||
2369 key.objectid != send_root->root_key.objectid) {
2370 ret = -ENOENT;
2371 goto out;
2372 }
2373 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
2374 namelen = btrfs_root_ref_name_len(leaf, ref);
2375 read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen);
2376 btrfs_release_path(path);
2377
2378 if (parent_root) {
2379 ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT);
2380 if (ret < 0)
2381 goto out;
2382 } else {
2383 ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL);
2384 if (ret < 0)
2385 goto out;
2386 }
2387
2388 TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen);
2389
2390 if (!btrfs_is_empty_uuid(sctx->send_root->root_item.received_uuid))
2391 TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
2392 sctx->send_root->root_item.received_uuid);
2393 else
2394 TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
2395 sctx->send_root->root_item.uuid);
2396
2397 TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID,
2398 btrfs_root_ctransid(&sctx->send_root->root_item));
2399 if (parent_root) {
2400 if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid))
2401 TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
2402 parent_root->root_item.received_uuid);
2403 else
2404 TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
2405 parent_root->root_item.uuid);
2406 TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
2407 btrfs_root_ctransid(&sctx->parent_root->root_item));
2408 }
2409
2410 ret = send_cmd(sctx);
2411
2412 tlv_put_failure:
2413 out:
2414 btrfs_free_path(path);
2415 kfree(name);
2416 return ret;
2417 }
2418
2419 static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size)
2420 {
2421 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2422 int ret = 0;
2423 struct fs_path *p;
2424
2425 btrfs_debug(fs_info, "send_truncate %llu size=%llu", ino, size);
2426
2427 p = fs_path_alloc();
2428 if (!p)
2429 return -ENOMEM;
2430
2431 ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE);
2432 if (ret < 0)
2433 goto out;
2434
2435 ret = get_cur_path(sctx, ino, gen, p);
2436 if (ret < 0)
2437 goto out;
2438 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2439 TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size);
2440
2441 ret = send_cmd(sctx);
2442
2443 tlv_put_failure:
2444 out:
2445 fs_path_free(p);
2446 return ret;
2447 }
2448
2449 static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode)
2450 {
2451 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2452 int ret = 0;
2453 struct fs_path *p;
2454
2455 btrfs_debug(fs_info, "send_chmod %llu mode=%llu", ino, mode);
2456
2457 p = fs_path_alloc();
2458 if (!p)
2459 return -ENOMEM;
2460
2461 ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD);
2462 if (ret < 0)
2463 goto out;
2464
2465 ret = get_cur_path(sctx, ino, gen, p);
2466 if (ret < 0)
2467 goto out;
2468 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2469 TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777);
2470
2471 ret = send_cmd(sctx);
2472
2473 tlv_put_failure:
2474 out:
2475 fs_path_free(p);
2476 return ret;
2477 }
2478
2479 static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid)
2480 {
2481 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2482 int ret = 0;
2483 struct fs_path *p;
2484
2485 btrfs_debug(fs_info, "send_chown %llu uid=%llu, gid=%llu",
2486 ino, uid, gid);
2487
2488 p = fs_path_alloc();
2489 if (!p)
2490 return -ENOMEM;
2491
2492 ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN);
2493 if (ret < 0)
2494 goto out;
2495
2496 ret = get_cur_path(sctx, ino, gen, p);
2497 if (ret < 0)
2498 goto out;
2499 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2500 TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid);
2501 TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid);
2502
2503 ret = send_cmd(sctx);
2504
2505 tlv_put_failure:
2506 out:
2507 fs_path_free(p);
2508 return ret;
2509 }
2510
2511 static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen)
2512 {
2513 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2514 int ret = 0;
2515 struct fs_path *p = NULL;
2516 struct btrfs_inode_item *ii;
2517 struct btrfs_path *path = NULL;
2518 struct extent_buffer *eb;
2519 struct btrfs_key key;
2520 int slot;
2521
2522 btrfs_debug(fs_info, "send_utimes %llu", ino);
2523
2524 p = fs_path_alloc();
2525 if (!p)
2526 return -ENOMEM;
2527
2528 path = alloc_path_for_send();
2529 if (!path) {
2530 ret = -ENOMEM;
2531 goto out;
2532 }
2533
2534 key.objectid = ino;
2535 key.type = BTRFS_INODE_ITEM_KEY;
2536 key.offset = 0;
2537 ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
2538 if (ret > 0)
2539 ret = -ENOENT;
2540 if (ret < 0)
2541 goto out;
2542
2543 eb = path->nodes[0];
2544 slot = path->slots[0];
2545 ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);
2546
2547 ret = begin_cmd(sctx, BTRFS_SEND_C_UTIMES);
2548 if (ret < 0)
2549 goto out;
2550
2551 ret = get_cur_path(sctx, ino, gen, p);
2552 if (ret < 0)
2553 goto out;
2554 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2555 TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, eb, &ii->atime);
2556 TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb, &ii->mtime);
2557 TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb, &ii->ctime);
2558 /* TODO Add otime support when the otime patches get into upstream */
2559
2560 ret = send_cmd(sctx);
2561
2562 tlv_put_failure:
2563 out:
2564 fs_path_free(p);
2565 btrfs_free_path(path);
2566 return ret;
2567 }
2568
2569 /*
2570 * Sends a BTRFS_SEND_C_MKXXX or SYMLINK command to user space. We don't have
2571 * a valid path yet because we did not process the refs yet. So, the inode
2572 * is created as orphan.
2573 */
2574 static int send_create_inode(struct send_ctx *sctx, u64 ino)
2575 {
2576 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2577 int ret = 0;
2578 struct fs_path *p;
2579 int cmd;
2580 u64 gen;
2581 u64 mode;
2582 u64 rdev;
2583
2584 btrfs_debug(fs_info, "send_create_inode %llu", ino);
2585
2586 p = fs_path_alloc();
2587 if (!p)
2588 return -ENOMEM;
2589
2590 if (ino != sctx->cur_ino) {
2591 ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode,
2592 NULL, NULL, &rdev);
2593 if (ret < 0)
2594 goto out;
2595 } else {
2596 gen = sctx->cur_inode_gen;
2597 mode = sctx->cur_inode_mode;
2598 rdev = sctx->cur_inode_rdev;
2599 }
2600
2601 if (S_ISREG(mode)) {
2602 cmd = BTRFS_SEND_C_MKFILE;
2603 } else if (S_ISDIR(mode)) {
2604 cmd = BTRFS_SEND_C_MKDIR;
2605 } else if (S_ISLNK(mode)) {
2606 cmd = BTRFS_SEND_C_SYMLINK;
2607 } else if (S_ISCHR(mode) || S_ISBLK(mode)) {
2608 cmd = BTRFS_SEND_C_MKNOD;
2609 } else if (S_ISFIFO(mode)) {
2610 cmd = BTRFS_SEND_C_MKFIFO;
2611 } else if (S_ISSOCK(mode)) {
2612 cmd = BTRFS_SEND_C_MKSOCK;
2613 } else {
2614 btrfs_warn(sctx->send_root->fs_info, "unexpected inode type %o",
2615 (int)(mode & S_IFMT));
2616 ret = -EOPNOTSUPP;
2617 goto out;
2618 }
2619
2620 ret = begin_cmd(sctx, cmd);
2621 if (ret < 0)
2622 goto out;
2623
2624 ret = gen_unique_name(sctx, ino, gen, p);
2625 if (ret < 0)
2626 goto out;
2627
2628 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2629 TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino);
2630
2631 if (S_ISLNK(mode)) {
2632 fs_path_reset(p);
2633 ret = read_symlink(sctx->send_root, ino, p);
2634 if (ret < 0)
2635 goto out;
2636 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p);
2637 } else if (S_ISCHR(mode) || S_ISBLK(mode) ||
2638 S_ISFIFO(mode) || S_ISSOCK(mode)) {
2639 TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, new_encode_dev(rdev));
2640 TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode);
2641 }
2642
2643 ret = send_cmd(sctx);
2644 if (ret < 0)
2645 goto out;
2646
2647
2648 tlv_put_failure:
2649 out:
2650 fs_path_free(p);
2651 return ret;
2652 }
2653
2654 /*
2655 * We need some special handling for inodes that get processed before the parent
2656 * directory got created. See process_recorded_refs for details.
2657 * This function does the check if we already created the dir out of order.
2658 */
2659 static int did_create_dir(struct send_ctx *sctx, u64 dir)
2660 {
2661 int ret = 0;
2662 struct btrfs_path *path = NULL;
2663 struct btrfs_key key;
2664 struct btrfs_key found_key;
2665 struct btrfs_key di_key;
2666 struct extent_buffer *eb;
2667 struct btrfs_dir_item *di;
2668 int slot;
2669
2670 path = alloc_path_for_send();
2671 if (!path) {
2672 ret = -ENOMEM;
2673 goto out;
2674 }
2675
2676 key.objectid = dir;
2677 key.type = BTRFS_DIR_INDEX_KEY;
2678 key.offset = 0;
2679 ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
2680 if (ret < 0)
2681 goto out;
2682
2683 while (1) {
2684 eb = path->nodes[0];
2685 slot = path->slots[0];
2686 if (slot >= btrfs_header_nritems(eb)) {
2687 ret = btrfs_next_leaf(sctx->send_root, path);
2688 if (ret < 0) {
2689 goto out;
2690 } else if (ret > 0) {
2691 ret = 0;
2692 break;
2693 }
2694 continue;
2695 }
2696
2697 btrfs_item_key_to_cpu(eb, &found_key, slot);
2698 if (found_key.objectid != key.objectid ||
2699 found_key.type != key.type) {
2700 ret = 0;
2701 goto out;
2702 }
2703
2704 di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
2705 btrfs_dir_item_key_to_cpu(eb, di, &di_key);
2706
2707 if (di_key.type != BTRFS_ROOT_ITEM_KEY &&
2708 di_key.objectid < sctx->send_progress) {
2709 ret = 1;
2710 goto out;
2711 }
2712
2713 path->slots[0]++;
2714 }
2715
2716 out:
2717 btrfs_free_path(path);
2718 return ret;
2719 }
2720
2721 /*
2722 * Only creates the inode if it is:
2723 * 1. Not a directory
2724 * 2. Or a directory which was not created already due to out of order
2725 * directories. See did_create_dir and process_recorded_refs for details.
2726 */
2727 static int send_create_inode_if_needed(struct send_ctx *sctx)
2728 {
2729 int ret;
2730
2731 if (S_ISDIR(sctx->cur_inode_mode)) {
2732 ret = did_create_dir(sctx, sctx->cur_ino);
2733 if (ret < 0)
2734 goto out;
2735 if (ret) {
2736 ret = 0;
2737 goto out;
2738 }
2739 }
2740
2741 ret = send_create_inode(sctx, sctx->cur_ino);
2742 if (ret < 0)
2743 goto out;
2744
2745 out:
2746 return ret;
2747 }
2748
2749 struct recorded_ref {
2750 struct list_head list;
2751 char *name;
2752 struct fs_path *full_path;
2753 u64 dir;
2754 u64 dir_gen;
2755 int name_len;
2756 };
2757
2758 static void set_ref_path(struct recorded_ref *ref, struct fs_path *path)
2759 {
2760 ref->full_path = path;
2761 ref->name = (char *)kbasename(ref->full_path->start);
2762 ref->name_len = ref->full_path->end - ref->name;
2763 }
2764
2765 /*
2766 * We need to process new refs before deleted refs, but compare_tree gives us
2767 * everything mixed. So we first record all refs and later process them.
2768 * This function is a helper to record one ref.
2769 */
2770 static int __record_ref(struct list_head *head, u64 dir,
2771 u64 dir_gen, struct fs_path *path)
2772 {
2773 struct recorded_ref *ref;
2774
2775 ref = kmalloc(sizeof(*ref), GFP_KERNEL);
2776 if (!ref)
2777 return -ENOMEM;
2778
2779 ref->dir = dir;
2780 ref->dir_gen = dir_gen;
2781 set_ref_path(ref, path);
2782 list_add_tail(&ref->list, head);
2783 return 0;
2784 }
2785
2786 static int dup_ref(struct recorded_ref *ref, struct list_head *list)
2787 {
2788 struct recorded_ref *new;
2789
2790 new = kmalloc(sizeof(*ref), GFP_KERNEL);
2791 if (!new)
2792 return -ENOMEM;
2793
2794 new->dir = ref->dir;
2795 new->dir_gen = ref->dir_gen;
2796 new->full_path = NULL;
2797 INIT_LIST_HEAD(&new->list);
2798 list_add_tail(&new->list, list);
2799 return 0;
2800 }
2801
2802 static void __free_recorded_refs(struct list_head *head)
2803 {
2804 struct recorded_ref *cur;
2805
2806 while (!list_empty(head)) {
2807 cur = list_entry(head->next, struct recorded_ref, list);
2808 fs_path_free(cur->full_path);
2809 list_del(&cur->list);
2810 kfree(cur);
2811 }
2812 }
2813
2814 static void free_recorded_refs(struct send_ctx *sctx)
2815 {
2816 __free_recorded_refs(&sctx->new_refs);
2817 __free_recorded_refs(&sctx->deleted_refs);
2818 }
2819
2820 /*
2821 * Renames/moves a file/dir to its orphan name. Used when the first
2822 * ref of an unprocessed inode gets overwritten and for all non empty
2823 * directories.
2824 */
2825 static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen,
2826 struct fs_path *path)
2827 {
2828 int ret;
2829 struct fs_path *orphan;
2830
2831 orphan = fs_path_alloc();
2832 if (!orphan)
2833 return -ENOMEM;
2834
2835 ret = gen_unique_name(sctx, ino, gen, orphan);
2836 if (ret < 0)
2837 goto out;
2838
2839 ret = send_rename(sctx, path, orphan);
2840
2841 out:
2842 fs_path_free(orphan);
2843 return ret;
2844 }
2845
2846 static struct orphan_dir_info *add_orphan_dir_info(struct send_ctx *sctx,
2847 u64 dir_ino, u64 dir_gen)
2848 {
2849 struct rb_node **p = &sctx->orphan_dirs.rb_node;
2850 struct rb_node *parent = NULL;
2851 struct orphan_dir_info *entry, *odi;
2852
2853 while (*p) {
2854 parent = *p;
2855 entry = rb_entry(parent, struct orphan_dir_info, node);
2856 if (dir_ino < entry->ino)
2857 p = &(*p)->rb_left;
2858 else if (dir_ino > entry->ino)
2859 p = &(*p)->rb_right;
2860 else if (dir_gen < entry->gen)
2861 p = &(*p)->rb_left;
2862 else if (dir_gen > entry->gen)
2863 p = &(*p)->rb_right;
2864 else
2865 return entry;
2866 }
2867
2868 odi = kmalloc(sizeof(*odi), GFP_KERNEL);
2869 if (!odi)
2870 return ERR_PTR(-ENOMEM);
2871 odi->ino = dir_ino;
2872 odi->gen = dir_gen;
2873 odi->last_dir_index_offset = 0;
2874
2875 rb_link_node(&odi->node, parent, p);
2876 rb_insert_color(&odi->node, &sctx->orphan_dirs);
2877 return odi;
2878 }
2879
2880 static struct orphan_dir_info *get_orphan_dir_info(struct send_ctx *sctx,
2881 u64 dir_ino, u64 gen)
2882 {
2883 struct rb_node *n = sctx->orphan_dirs.rb_node;
2884 struct orphan_dir_info *entry;
2885
2886 while (n) {
2887 entry = rb_entry(n, struct orphan_dir_info, node);
2888 if (dir_ino < entry->ino)
2889 n = n->rb_left;
2890 else if (dir_ino > entry->ino)
2891 n = n->rb_right;
2892 else if (gen < entry->gen)
2893 n = n->rb_left;
2894 else if (gen > entry->gen)
2895 n = n->rb_right;
2896 else
2897 return entry;
2898 }
2899 return NULL;
2900 }
2901
2902 static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen)
2903 {
2904 struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino, gen);
2905
2906 return odi != NULL;
2907 }
2908
2909 static void free_orphan_dir_info(struct send_ctx *sctx,
2910 struct orphan_dir_info *odi)
2911 {
2912 if (!odi)
2913 return;
2914 rb_erase(&odi->node, &sctx->orphan_dirs);
2915 kfree(odi);
2916 }
2917
2918 /*
2919 * Returns 1 if a directory can be removed at this point in time.
2920 * We check this by iterating all dir items and checking if the inode behind
2921 * the dir item was already processed.
2922 */
2923 static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen,
2924 u64 send_progress)
2925 {
2926 int ret = 0;
2927 struct btrfs_root *root = sctx->parent_root;
2928 struct btrfs_path *path;
2929 struct btrfs_key key;
2930 struct btrfs_key found_key;
2931 struct btrfs_key loc;
2932 struct btrfs_dir_item *di;
2933 struct orphan_dir_info *odi = NULL;
2934
2935 /*
2936 * Don't try to rmdir the top/root subvolume dir.
2937 */
2938 if (dir == BTRFS_FIRST_FREE_OBJECTID)
2939 return 0;
2940
2941 path = alloc_path_for_send();
2942 if (!path)
2943 return -ENOMEM;
2944
2945 key.objectid = dir;
2946 key.type = BTRFS_DIR_INDEX_KEY;
2947 key.offset = 0;
2948
2949 odi = get_orphan_dir_info(sctx, dir, dir_gen);
2950 if (odi)
2951 key.offset = odi->last_dir_index_offset;
2952
2953 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2954 if (ret < 0)
2955 goto out;
2956
2957 while (1) {
2958 struct waiting_dir_move *dm;
2959
2960 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
2961 ret = btrfs_next_leaf(root, path);
2962 if (ret < 0)
2963 goto out;
2964 else if (ret > 0)
2965 break;
2966 continue;
2967 }
2968 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2969 path->slots[0]);
2970 if (found_key.objectid != key.objectid ||
2971 found_key.type != key.type)
2972 break;
2973
2974 di = btrfs_item_ptr(path->nodes[0], path->slots[0],
2975 struct btrfs_dir_item);
2976 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc);
2977
2978 dm = get_waiting_dir_move(sctx, loc.objectid);
2979 if (dm) {
2980 odi = add_orphan_dir_info(sctx, dir, dir_gen);
2981 if (IS_ERR(odi)) {
2982 ret = PTR_ERR(odi);
2983 goto out;
2984 }
2985 odi->gen = dir_gen;
2986 odi->last_dir_index_offset = found_key.offset;
2987 dm->rmdir_ino = dir;
2988 dm->rmdir_gen = dir_gen;
2989 ret = 0;
2990 goto out;
2991 }
2992
2993 if (loc.objectid > send_progress) {
2994 odi = add_orphan_dir_info(sctx, dir, dir_gen);
2995 if (IS_ERR(odi)) {
2996 ret = PTR_ERR(odi);
2997 goto out;
2998 }
2999 odi->gen = dir_gen;
3000 odi->last_dir_index_offset = found_key.offset;
3001 ret = 0;
3002 goto out;
3003 }
3004
3005 path->slots[0]++;
3006 }
3007 free_orphan_dir_info(sctx, odi);
3008
3009 ret = 1;
3010
3011 out:
3012 btrfs_free_path(path);
3013 return ret;
3014 }
3015
3016 static int is_waiting_for_move(struct send_ctx *sctx, u64 ino)
3017 {
3018 struct waiting_dir_move *entry = get_waiting_dir_move(sctx, ino);
3019
3020 return entry != NULL;
3021 }
3022
3023 static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino, bool orphanized)
3024 {
3025 struct rb_node **p = &sctx->waiting_dir_moves.rb_node;
3026 struct rb_node *parent = NULL;
3027 struct waiting_dir_move *entry, *dm;
3028
3029 dm = kmalloc(sizeof(*dm), GFP_KERNEL);
3030 if (!dm)
3031 return -ENOMEM;
3032 dm->ino = ino;
3033 dm->rmdir_ino = 0;
3034 dm->rmdir_gen = 0;
3035 dm->orphanized = orphanized;
3036
3037 while (*p) {
3038 parent = *p;
3039 entry = rb_entry(parent, struct waiting_dir_move, node);
3040 if (ino < entry->ino) {
3041 p = &(*p)->rb_left;
3042 } else if (ino > entry->ino) {
3043 p = &(*p)->rb_right;
3044 } else {
3045 kfree(dm);
3046 return -EEXIST;
3047 }
3048 }
3049
3050 rb_link_node(&dm->node, parent, p);
3051 rb_insert_color(&dm->node, &sctx->waiting_dir_moves);
3052 return 0;
3053 }
3054
3055 static struct waiting_dir_move *
3056 get_waiting_dir_move(struct send_ctx *sctx, u64 ino)
3057 {
3058 struct rb_node *n = sctx->waiting_dir_moves.rb_node;
3059 struct waiting_dir_move *entry;
3060
3061 while (n) {
3062 entry = rb_entry(n, struct waiting_dir_move, node);
3063 if (ino < entry->ino)
3064 n = n->rb_left;
3065 else if (ino > entry->ino)
3066 n = n->rb_right;
3067 else
3068 return entry;
3069 }
3070 return NULL;
3071 }
3072
3073 static void free_waiting_dir_move(struct send_ctx *sctx,
3074 struct waiting_dir_move *dm)
3075 {
3076 if (!dm)
3077 return;
3078 rb_erase(&dm->node, &sctx->waiting_dir_moves);
3079 kfree(dm);
3080 }
3081
3082 static int add_pending_dir_move(struct send_ctx *sctx,
3083 u64 ino,
3084 u64 ino_gen,
3085 u64 parent_ino,
3086 struct list_head *new_refs,
3087 struct list_head *deleted_refs,
3088 const bool is_orphan)
3089 {
3090 struct rb_node **p = &sctx->pending_dir_moves.rb_node;
3091 struct rb_node *parent = NULL;
3092 struct pending_dir_move *entry = NULL, *pm;
3093 struct recorded_ref *cur;
3094 int exists = 0;
3095 int ret;
3096
3097 pm = kmalloc(sizeof(*pm), GFP_KERNEL);
3098 if (!pm)
3099 return -ENOMEM;
3100 pm->parent_ino = parent_ino;
3101 pm->ino = ino;
3102 pm->gen = ino_gen;
3103 INIT_LIST_HEAD(&pm->list);
3104 INIT_LIST_HEAD(&pm->update_refs);
3105 RB_CLEAR_NODE(&pm->node);
3106
3107 while (*p) {
3108 parent = *p;
3109 entry = rb_entry(parent, struct pending_dir_move, node);
3110 if (parent_ino < entry->parent_ino) {
3111 p = &(*p)->rb_left;
3112 } else if (parent_ino > entry->parent_ino) {
3113 p = &(*p)->rb_right;
3114 } else {
3115 exists = 1;
3116 break;
3117 }
3118 }
3119
3120 list_for_each_entry(cur, deleted_refs, list) {
3121 ret = dup_ref(cur, &pm->update_refs);
3122 if (ret < 0)
3123 goto out;
3124 }
3125 list_for_each_entry(cur, new_refs, list) {
3126 ret = dup_ref(cur, &pm->update_refs);
3127 if (ret < 0)
3128 goto out;
3129 }
3130
3131 ret = add_waiting_dir_move(sctx, pm->ino, is_orphan);
3132 if (ret)
3133 goto out;
3134
3135 if (exists) {
3136 list_add_tail(&pm->list, &entry->list);
3137 } else {
3138 rb_link_node(&pm->node, parent, p);
3139 rb_insert_color(&pm->node, &sctx->pending_dir_moves);
3140 }
3141 ret = 0;
3142 out:
3143 if (ret) {
3144 __free_recorded_refs(&pm->update_refs);
3145 kfree(pm);
3146 }
3147 return ret;
3148 }
3149
3150 static struct pending_dir_move *get_pending_dir_moves(struct send_ctx *sctx,
3151 u64 parent_ino)
3152 {
3153 struct rb_node *n = sctx->pending_dir_moves.rb_node;
3154 struct pending_dir_move *entry;
3155
3156 while (n) {
3157 entry = rb_entry(n, struct pending_dir_move, node);
3158 if (parent_ino < entry->parent_ino)
3159 n = n->rb_left;
3160 else if (parent_ino > entry->parent_ino)
3161 n = n->rb_right;
3162 else
3163 return entry;
3164 }
3165 return NULL;
3166 }
3167
3168 static int path_loop(struct send_ctx *sctx, struct fs_path *name,
3169 u64 ino, u64 gen, u64 *ancestor_ino)
3170 {
3171 int ret = 0;
3172 u64 parent_inode = 0;
3173 u64 parent_gen = 0;
3174 u64 start_ino = ino;
3175
3176 *ancestor_ino = 0;
3177 while (ino != BTRFS_FIRST_FREE_OBJECTID) {
3178 fs_path_reset(name);
3179
3180 if (is_waiting_for_rm(sctx, ino, gen))
3181 break;
3182 if (is_waiting_for_move(sctx, ino)) {
3183 if (*ancestor_ino == 0)
3184 *ancestor_ino = ino;
3185 ret = get_first_ref(sctx->parent_root, ino,
3186 &parent_inode, &parent_gen, name);
3187 } else {
3188 ret = __get_cur_name_and_parent(sctx, ino, gen,
3189 &parent_inode,
3190 &parent_gen, name);
3191 if (ret > 0) {
3192 ret = 0;
3193 break;
3194 }
3195 }
3196 if (ret < 0)
3197 break;
3198 if (parent_inode == start_ino) {
3199 ret = 1;
3200 if (*ancestor_ino == 0)
3201 *ancestor_ino = ino;
3202 break;
3203 }
3204 ino = parent_inode;
3205 gen = parent_gen;
3206 }
3207 return ret;
3208 }
3209
3210 static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm)
3211 {
3212 struct fs_path *from_path = NULL;
3213 struct fs_path *to_path = NULL;
3214 struct fs_path *name = NULL;
3215 u64 orig_progress = sctx->send_progress;
3216 struct recorded_ref *cur;
3217 u64 parent_ino, parent_gen;
3218 struct waiting_dir_move *dm = NULL;
3219 u64 rmdir_ino = 0;
3220 u64 rmdir_gen;
3221 u64 ancestor;
3222 bool is_orphan;
3223 int ret;
3224
3225 name = fs_path_alloc();
3226 from_path = fs_path_alloc();
3227 if (!name || !from_path) {
3228 ret = -ENOMEM;
3229 goto out;
3230 }
3231
3232 dm = get_waiting_dir_move(sctx, pm->ino);
3233 ASSERT(dm);
3234 rmdir_ino = dm->rmdir_ino;
3235 rmdir_gen = dm->rmdir_gen;
3236 is_orphan = dm->orphanized;
3237 free_waiting_dir_move(sctx, dm);
3238
3239 if (is_orphan) {
3240 ret = gen_unique_name(sctx, pm->ino,
3241 pm->gen, from_path);
3242 } else {
3243 ret = get_first_ref(sctx->parent_root, pm->ino,
3244 &parent_ino, &parent_gen, name);
3245 if (ret < 0)
3246 goto out;
3247 ret = get_cur_path(sctx, parent_ino, parent_gen,
3248 from_path);
3249 if (ret < 0)
3250 goto out;
3251 ret = fs_path_add_path(from_path, name);
3252 }
3253 if (ret < 0)
3254 goto out;
3255
3256 sctx->send_progress = sctx->cur_ino + 1;
3257 ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor);
3258 if (ret < 0)
3259 goto out;
3260 if (ret) {
3261 LIST_HEAD(deleted_refs);
3262 ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID);
3263 ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor,
3264 &pm->update_refs, &deleted_refs,
3265 is_orphan);
3266 if (ret < 0)
3267 goto out;
3268 if (rmdir_ino) {
3269 dm = get_waiting_dir_move(sctx, pm->ino);
3270 ASSERT(dm);
3271 dm->rmdir_ino = rmdir_ino;
3272 dm->rmdir_gen = rmdir_gen;
3273 }
3274 goto out;
3275 }
3276 fs_path_reset(name);
3277 to_path = name;
3278 name = NULL;
3279 ret = get_cur_path(sctx, pm->ino, pm->gen, to_path);
3280 if (ret < 0)
3281 goto out;
3282
3283 ret = send_rename(sctx, from_path, to_path);
3284 if (ret < 0)
3285 goto out;
3286
3287 if (rmdir_ino) {
3288 struct orphan_dir_info *odi;
3289 u64 gen;
3290
3291 odi = get_orphan_dir_info(sctx, rmdir_ino, rmdir_gen);
3292 if (!odi) {
3293 /* already deleted */
3294 goto finish;
3295 }
3296 gen = odi->gen;
3297
3298 ret = can_rmdir(sctx, rmdir_ino, gen, sctx->cur_ino);
3299 if (ret < 0)
3300 goto out;
3301 if (!ret)
3302 goto finish;
3303
3304 name = fs_path_alloc();
3305 if (!name) {
3306 ret = -ENOMEM;
3307 goto out;
3308 }
3309 ret = get_cur_path(sctx, rmdir_ino, gen, name);
3310 if (ret < 0)
3311 goto out;
3312 ret = send_rmdir(sctx, name);
3313 if (ret < 0)
3314 goto out;
3315 }
3316
3317 finish:
3318 ret = send_utimes(sctx, pm->ino, pm->gen);
3319 if (ret < 0)
3320 goto out;
3321
3322 /*
3323 * After rename/move, need to update the utimes of both new parent(s)
3324 * and old parent(s).
3325 */
3326 list_for_each_entry(cur, &pm->update_refs, list) {
3327 /*
3328 * The parent inode might have been deleted in the send snapshot
3329 */
3330 ret = get_inode_info(sctx->send_root, cur->dir, NULL,
3331 NULL, NULL, NULL, NULL, NULL);
3332 if (ret == -ENOENT) {
3333 ret = 0;
3334 continue;
3335 }
3336 if (ret < 0)
3337 goto out;
3338
3339 ret = send_utimes(sctx, cur->dir, cur->dir_gen);
3340 if (ret < 0)
3341 goto out;
3342 }
3343
3344 out:
3345 fs_path_free(name);
3346 fs_path_free(from_path);
3347 fs_path_free(to_path);
3348 sctx->send_progress = orig_progress;
3349
3350 return ret;
3351 }
3352
3353 static void free_pending_move(struct send_ctx *sctx, struct pending_dir_move *m)
3354 {
3355 if (!list_empty(&m->list))
3356 list_del(&m->list);
3357 if (!RB_EMPTY_NODE(&m->node))
3358 rb_erase(&m->node, &sctx->pending_dir_moves);
3359 __free_recorded_refs(&m->update_refs);
3360 kfree(m);
3361 }
3362
3363 static void tail_append_pending_moves(struct send_ctx *sctx,
3364 struct pending_dir_move *moves,
3365 struct list_head *stack)
3366 {
3367 if (list_empty(&moves->list)) {
3368 list_add_tail(&moves->list, stack);
3369 } else {
3370 LIST_HEAD(list);
3371 list_splice_init(&moves->list, &list);
3372 list_add_tail(&moves->list, stack);
3373 list_splice_tail(&list, stack);
3374 }
3375 if (!RB_EMPTY_NODE(&moves->node)) {
3376 rb_erase(&moves->node, &sctx->pending_dir_moves);
3377 RB_CLEAR_NODE(&moves->node);
3378 }
3379 }
3380
3381 static int apply_children_dir_moves(struct send_ctx *sctx)
3382 {
3383 struct pending_dir_move *pm;
3384 struct list_head stack;
3385 u64 parent_ino = sctx->cur_ino;
3386 int ret = 0;
3387
3388 pm = get_pending_dir_moves(sctx, parent_ino);
3389 if (!pm)
3390 return 0;
3391
3392 INIT_LIST_HEAD(&stack);
3393 tail_append_pending_moves(sctx, pm, &stack);
3394
3395 while (!list_empty(&stack)) {
3396 pm = list_first_entry(&stack, struct pending_dir_move, list);
3397 parent_ino = pm->ino;
3398 ret = apply_dir_move(sctx, pm);
3399 free_pending_move(sctx, pm);
3400 if (ret)
3401 goto out;
3402 pm = get_pending_dir_moves(sctx, parent_ino);
3403 if (pm)
3404 tail_append_pending_moves(sctx, pm, &stack);
3405 }
3406 return 0;
3407
3408 out:
3409 while (!list_empty(&stack)) {
3410 pm = list_first_entry(&stack, struct pending_dir_move, list);
3411 free_pending_move(sctx, pm);
3412 }
3413 return ret;
3414 }
3415
3416 /*
3417 * We might need to delay a directory rename even when no ancestor directory
3418 * (in the send root) with a higher inode number than ours (sctx->cur_ino) was
3419 * renamed. This happens when we rename a directory to the old name (the name
3420 * in the parent root) of some other unrelated directory that got its rename
3421 * delayed due to some ancestor with higher number that got renamed.
3422 *
3423 * Example:
3424 *
3425 * Parent snapshot:
3426 * . (ino 256)
3427 * |---- a/ (ino 257)
3428 * | |---- file (ino 260)
3429 * |
3430 * |---- b/ (ino 258)
3431 * |---- c/ (ino 259)
3432 *
3433 * Send snapshot:
3434 * . (ino 256)
3435 * |---- a/ (ino 258)
3436 * |---- x/ (ino 259)
3437 * |---- y/ (ino 257)
3438 * |----- file (ino 260)
3439 *
3440 * Here we can not rename 258 from 'b' to 'a' without the rename of inode 257
3441 * from 'a' to 'x/y' happening first, which in turn depends on the rename of
3442 * inode 259 from 'c' to 'x'. So the order of rename commands the send stream
3443 * must issue is:
3444 *
3445 * 1 - rename 259 from 'c' to 'x'
3446 * 2 - rename 257 from 'a' to 'x/y'
3447 * 3 - rename 258 from 'b' to 'a'
3448 *
3449 * Returns 1 if the rename of sctx->cur_ino needs to be delayed, 0 if it can
3450 * be done right away and < 0 on error.
3451 */
3452 static int wait_for_dest_dir_move(struct send_ctx *sctx,
3453 struct recorded_ref *parent_ref,
3454 const bool is_orphan)
3455 {
3456 struct btrfs_fs_info *fs_info = sctx->parent_root->fs_info;
3457 struct btrfs_path *path;
3458 struct btrfs_key key;
3459 struct btrfs_key di_key;
3460 struct btrfs_dir_item *di;
3461 u64 left_gen;
3462 u64 right_gen;
3463 int ret = 0;
3464 struct waiting_dir_move *wdm;
3465
3466 if (RB_EMPTY_ROOT(&sctx->waiting_dir_moves))
3467 return 0;
3468
3469 path = alloc_path_for_send();
3470 if (!path)
3471 return -ENOMEM;
3472
3473 key.objectid = parent_ref->dir;
3474 key.type = BTRFS_DIR_ITEM_KEY;
3475 key.offset = btrfs_name_hash(parent_ref->name, parent_ref->name_len);
3476
3477 ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0);
3478 if (ret < 0) {
3479 goto out;
3480 } else if (ret > 0) {
3481 ret = 0;
3482 goto out;
3483 }
3484
3485 di = btrfs_match_dir_item_name(fs_info, path, parent_ref->name,
3486 parent_ref->name_len);
3487 if (!di) {
3488 ret = 0;
3489 goto out;
3490 }
3491 /*
3492 * di_key.objectid has the number of the inode that has a dentry in the
3493 * parent directory with the same name that sctx->cur_ino is being
3494 * renamed to. We need to check if that inode is in the send root as
3495 * well and if it is currently marked as an inode with a pending rename,
3496 * if it is, we need to delay the rename of sctx->cur_ino as well, so
3497 * that it happens after that other inode is renamed.
3498 */
3499 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &di_key);
3500 if (di_key.type != BTRFS_INODE_ITEM_KEY) {
3501 ret = 0;
3502 goto out;
3503 }
3504
3505 ret = get_inode_info(sctx->parent_root, di_key.objectid, NULL,
3506 &left_gen, NULL, NULL, NULL, NULL);
3507 if (ret < 0)
3508 goto out;
3509 ret = get_inode_info(sctx->send_root, di_key.objectid, NULL,
3510 &right_gen, NULL, NULL, NULL, NULL);
3511 if (ret < 0) {
3512 if (ret == -ENOENT)
3513 ret = 0;
3514 goto out;
3515 }
3516
3517 /* Different inode, no need to delay the rename of sctx->cur_ino */
3518 if (right_gen != left_gen) {
3519 ret = 0;
3520 goto out;
3521 }
3522
3523 wdm = get_waiting_dir_move(sctx, di_key.objectid);
3524 if (wdm && !wdm->orphanized) {
3525 ret = add_pending_dir_move(sctx,
3526 sctx->cur_ino,
3527 sctx->cur_inode_gen,
3528 di_key.objectid,
3529 &sctx->new_refs,
3530 &sctx->deleted_refs,
3531 is_orphan);
3532 if (!ret)
3533 ret = 1;
3534 }
3535 out:
3536 btrfs_free_path(path);
3537 return ret;
3538 }
3539
3540 /*
3541 * Check if inode ino2, or any of its ancestors, is inode ino1.
3542 * Return 1 if true, 0 if false and < 0 on error.
3543 */
3544 static int check_ino_in_path(struct btrfs_root *root,
3545 const u64 ino1,
3546 const u64 ino1_gen,
3547 const u64 ino2,
3548 const u64 ino2_gen,
3549 struct fs_path *fs_path)
3550 {
3551 u64 ino = ino2;
3552
3553 if (ino1 == ino2)
3554 return ino1_gen == ino2_gen;
3555
3556 while (ino > BTRFS_FIRST_FREE_OBJECTID) {
3557 u64 parent;
3558 u64 parent_gen;
3559 int ret;
3560
3561 fs_path_reset(fs_path);
3562 ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path);
3563 if (ret < 0)
3564 return ret;
3565 if (parent == ino1)
3566 return parent_gen == ino1_gen;
3567 ino = parent;
3568 }
3569 return 0;
3570 }
3571
3572 /*
3573 * Check if ino ino1 is an ancestor of inode ino2 in the given root for any
3574 * possible path (in case ino2 is not a directory and has multiple hard links).
3575 * Return 1 if true, 0 if false and < 0 on error.
3576 */
3577 static int is_ancestor(struct btrfs_root *root,
3578 const u64 ino1,
3579 const u64 ino1_gen,
3580 const u64 ino2,
3581 struct fs_path *fs_path)
3582 {
3583 bool free_fs_path = false;
3584 int ret = 0;
3585 struct btrfs_path *path = NULL;
3586 struct btrfs_key key;
3587
3588 if (!fs_path) {
3589 fs_path = fs_path_alloc();
3590 if (!fs_path)
3591 return -ENOMEM;
3592 free_fs_path = true;
3593 }
3594
3595 path = alloc_path_for_send();
3596 if (!path) {
3597 ret = -ENOMEM;
3598 goto out;
3599 }
3600
3601 key.objectid = ino2;
3602 key.type = BTRFS_INODE_REF_KEY;
3603 key.offset = 0;
3604
3605 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3606 if (ret < 0)
3607 goto out;
3608
3609 while (true) {
3610 struct extent_buffer *leaf = path->nodes[0];
3611 int slot = path->slots[0];
3612 u32 cur_offset = 0;
3613 u32 item_size;
3614
3615 if (slot >= btrfs_header_nritems(leaf)) {
3616 ret = btrfs_next_leaf(root, path);
3617 if (ret < 0)
3618 goto out;
3619 if (ret > 0)
3620 break;
3621 continue;
3622 }
3623
3624 btrfs_item_key_to_cpu(leaf, &key, slot);
3625 if (key.objectid != ino2)
3626 break;
3627 if (key.type != BTRFS_INODE_REF_KEY &&
3628 key.type != BTRFS_INODE_EXTREF_KEY)
3629 break;
3630
3631 item_size = btrfs_item_size_nr(leaf, slot);
3632 while (cur_offset < item_size) {
3633 u64 parent;
3634 u64 parent_gen;
3635
3636 if (key.type == BTRFS_INODE_EXTREF_KEY) {
3637 unsigned long ptr;
3638 struct btrfs_inode_extref *extref;
3639
3640 ptr = btrfs_item_ptr_offset(leaf, slot);
3641 extref = (struct btrfs_inode_extref *)
3642 (ptr + cur_offset);
3643 parent = btrfs_inode_extref_parent(leaf,
3644 extref);
3645 cur_offset += sizeof(*extref);
3646 cur_offset += btrfs_inode_extref_name_len(leaf,
3647 extref);
3648 } else {
3649 parent = key.offset;
3650 cur_offset = item_size;
3651 }
3652
3653 ret = get_inode_info(root, parent, NULL, &parent_gen,
3654 NULL, NULL, NULL, NULL);
3655 if (ret < 0)
3656 goto out;
3657 ret = check_ino_in_path(root, ino1, ino1_gen,
3658 parent, parent_gen, fs_path);
3659 if (ret)
3660 goto out;
3661 }
3662 path->slots[0]++;
3663 }
3664 ret = 0;
3665 out:
3666 btrfs_free_path(path);
3667 if (free_fs_path)
3668 fs_path_free(fs_path);
3669 return ret;
3670 }
3671
3672 static int wait_for_parent_move(struct send_ctx *sctx,
3673 struct recorded_ref *parent_ref,
3674 const bool is_orphan)
3675 {
3676 int ret = 0;
3677 u64 ino = parent_ref->dir;
3678 u64 ino_gen = parent_ref->dir_gen;
3679 u64 parent_ino_before, parent_ino_after;
3680 struct fs_path *path_before = NULL;
3681 struct fs_path *path_after = NULL;
3682 int len1, len2;
3683
3684 path_after = fs_path_alloc();
3685 path_before = fs_path_alloc();
3686 if (!path_after || !path_before) {
3687 ret = -ENOMEM;
3688 goto out;
3689 }
3690
3691 /*
3692 * Our current directory inode may not yet be renamed/moved because some
3693 * ancestor (immediate or not) has to be renamed/moved first. So find if
3694 * such ancestor exists and make sure our own rename/move happens after
3695 * that ancestor is processed to avoid path build infinite loops (done
3696 * at get_cur_path()).
3697 */
3698 while (ino > BTRFS_FIRST_FREE_OBJECTID) {
3699 u64 parent_ino_after_gen;
3700
3701 if (is_waiting_for_move(sctx, ino)) {
3702 /*
3703 * If the current inode is an ancestor of ino in the
3704 * parent root, we need to delay the rename of the
3705 * current inode, otherwise don't delayed the rename
3706 * because we can end up with a circular dependency
3707 * of renames, resulting in some directories never
3708 * getting the respective rename operations issued in
3709 * the send stream or getting into infinite path build
3710 * loops.
3711 */
3712 ret = is_ancestor(sctx->parent_root,
3713 sctx->cur_ino, sctx->cur_inode_gen,
3714 ino, path_before);
3715 if (ret)
3716 break;
3717 }
3718
3719 fs_path_reset(path_before);
3720 fs_path_reset(path_after);
3721
3722 ret = get_first_ref(sctx->send_root, ino, &parent_ino_after,
3723 &parent_ino_after_gen, path_after);
3724 if (ret < 0)
3725 goto out;
3726 ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before,
3727 NULL, path_before);
3728 if (ret < 0 && ret != -ENOENT) {
3729 goto out;
3730 } else if (ret == -ENOENT) {
3731 ret = 0;
3732 break;
3733 }
3734
3735 len1 = fs_path_len(path_before);
3736 len2 = fs_path_len(path_after);
3737 if (ino > sctx->cur_ino &&
3738 (parent_ino_before != parent_ino_after || len1 != len2 ||
3739 memcmp(path_before->start, path_after->start, len1))) {
3740 u64 parent_ino_gen;
3741
3742 ret = get_inode_info(sctx->parent_root, ino, NULL,
3743 &parent_ino_gen, NULL, NULL, NULL,
3744 NULL);
3745 if (ret < 0)
3746 goto out;
3747 if (ino_gen == parent_ino_gen) {
3748 ret = 1;
3749 break;
3750 }
3751 }
3752 ino = parent_ino_after;
3753 ino_gen = parent_ino_after_gen;
3754 }
3755
3756 out:
3757 fs_path_free(path_before);
3758 fs_path_free(path_after);
3759
3760 if (ret == 1) {
3761 ret = add_pending_dir_move(sctx,
3762 sctx->cur_ino,
3763 sctx->cur_inode_gen,
3764 ino,
3765 &sctx->new_refs,
3766 &sctx->deleted_refs,
3767 is_orphan);
3768 if (!ret)
3769 ret = 1;
3770 }
3771
3772 return ret;
3773 }
3774
3775 static int update_ref_path(struct send_ctx *sctx, struct recorded_ref *ref)
3776 {
3777 int ret;
3778 struct fs_path *new_path;
3779
3780 /*
3781 * Our reference's name member points to its full_path member string, so
3782 * we use here a new path.
3783 */
3784 new_path = fs_path_alloc();
3785 if (!new_path)
3786 return -ENOMEM;
3787
3788 ret = get_cur_path(sctx, ref->dir, ref->dir_gen, new_path);
3789 if (ret < 0) {
3790 fs_path_free(new_path);
3791 return ret;
3792 }
3793 ret = fs_path_add(new_path, ref->name, ref->name_len);
3794 if (ret < 0) {
3795 fs_path_free(new_path);
3796 return ret;
3797 }
3798
3799 fs_path_free(ref->full_path);
3800 set_ref_path(ref, new_path);
3801
3802 return 0;
3803 }
3804
3805 /*
3806 * When processing the new references for an inode we may orphanize an existing
3807 * directory inode because its old name conflicts with one of the new references
3808 * of the current inode. Later, when processing another new reference of our
3809 * inode, we might need to orphanize another inode, but the path we have in the
3810 * reference reflects the pre-orphanization name of the directory we previously
3811 * orphanized. For example:
3812 *
3813 * parent snapshot looks like:
3814 *
3815 * . (ino 256)
3816 * |----- f1 (ino 257)
3817 * |----- f2 (ino 258)
3818 * |----- d1/ (ino 259)
3819 * |----- d2/ (ino 260)
3820 *
3821 * send snapshot looks like:
3822 *
3823 * . (ino 256)
3824 * |----- d1 (ino 258)
3825 * |----- f2/ (ino 259)
3826 * |----- f2_link/ (ino 260)
3827 * | |----- f1 (ino 257)
3828 * |
3829 * |----- d2 (ino 258)
3830 *
3831 * When processing inode 257 we compute the name for inode 259 as "d1", and we
3832 * cache it in the name cache. Later when we start processing inode 258, when
3833 * collecting all its new references we set a full path of "d1/d2" for its new
3834 * reference with name "d2". When we start processing the new references we
3835 * start by processing the new reference with name "d1", and this results in
3836 * orphanizing inode 259, since its old reference causes a conflict. Then we
3837 * move on the next new reference, with name "d2", and we find out we must
3838 * orphanize inode 260, as its old reference conflicts with ours - but for the
3839 * orphanization we use a source path corresponding to the path we stored in the
3840 * new reference, which is "d1/d2" and not "o259-6-0/d2" - this makes the
3841 * receiver fail since the path component "d1/" no longer exists, it was renamed
3842 * to "o259-6-0/" when processing the previous new reference. So in this case we
3843 * must recompute the path in the new reference and use it for the new
3844 * orphanization operation.
3845 */
3846 static int refresh_ref_path(struct send_ctx *sctx, struct recorded_ref *ref)
3847 {
3848 char *name;
3849 int ret;
3850
3851 name = kmemdup(ref->name, ref->name_len, GFP_KERNEL);
3852 if (!name)
3853 return -ENOMEM;
3854
3855 fs_path_reset(ref->full_path);
3856 ret = get_cur_path(sctx, ref->dir, ref->dir_gen, ref->full_path);
3857 if (ret < 0)
3858 goto out;
3859
3860 ret = fs_path_add(ref->full_path, name, ref->name_len);
3861 if (ret < 0)
3862 goto out;
3863
3864 /* Update the reference's base name pointer. */
3865 set_ref_path(ref, ref->full_path);
3866 out:
3867 kfree(name);
3868 return ret;
3869 }
3870
3871 /*
3872 * This does all the move/link/unlink/rmdir magic.
3873 */
3874 static int process_recorded_refs(struct send_ctx *sctx, int *pending_move)
3875 {
3876 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
3877 int ret = 0;
3878 struct recorded_ref *cur;
3879 struct recorded_ref *cur2;
3880 struct list_head check_dirs;
3881 struct fs_path *valid_path = NULL;
3882 u64 ow_inode = 0;
3883 u64 ow_gen;
3884 u64 ow_mode;
3885 int did_overwrite = 0;
3886 int is_orphan = 0;
3887 u64 last_dir_ino_rm = 0;
3888 bool can_rename = true;
3889 bool orphanized_dir = false;
3890 bool orphanized_ancestor = false;
3891
3892 btrfs_debug(fs_info, "process_recorded_refs %llu", sctx->cur_ino);
3893
3894 /*
3895 * This should never happen as the root dir always has the same ref
3896 * which is always '..'
3897 */
3898 BUG_ON(sctx->cur_ino <= BTRFS_FIRST_FREE_OBJECTID);
3899 INIT_LIST_HEAD(&check_dirs);
3900
3901 valid_path = fs_path_alloc();
3902 if (!valid_path) {
3903 ret = -ENOMEM;
3904 goto out;
3905 }
3906
3907 /*
3908 * First, check if the first ref of the current inode was overwritten
3909 * before. If yes, we know that the current inode was already orphanized
3910 * and thus use the orphan name. If not, we can use get_cur_path to
3911 * get the path of the first ref as it would like while receiving at
3912 * this point in time.
3913 * New inodes are always orphan at the beginning, so force to use the
3914 * orphan name in this case.
3915 * The first ref is stored in valid_path and will be updated if it
3916 * gets moved around.
3917 */
3918 if (!sctx->cur_inode_new) {
3919 ret = did_overwrite_first_ref(sctx, sctx->cur_ino,
3920 sctx->cur_inode_gen);
3921 if (ret < 0)
3922 goto out;
3923 if (ret)
3924 did_overwrite = 1;
3925 }
3926 if (sctx->cur_inode_new || did_overwrite) {
3927 ret = gen_unique_name(sctx, sctx->cur_ino,
3928 sctx->cur_inode_gen, valid_path);
3929 if (ret < 0)
3930 goto out;
3931 is_orphan = 1;
3932 } else {
3933 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen,
3934 valid_path);
3935 if (ret < 0)
3936 goto out;
3937 }
3938
3939 /*
3940 * Before doing any rename and link operations, do a first pass on the
3941 * new references to orphanize any unprocessed inodes that may have a
3942 * reference that conflicts with one of the new references of the current
3943 * inode. This needs to happen first because a new reference may conflict
3944 * with the old reference of a parent directory, so we must make sure
3945 * that the path used for link and rename commands don't use an
3946 * orphanized name when an ancestor was not yet orphanized.
3947 *
3948 * Example:
3949 *
3950 * Parent snapshot:
3951 *
3952 * . (ino 256)
3953 * |----- testdir/ (ino 259)
3954 * | |----- a (ino 257)
3955 * |
3956 * |----- b (ino 258)
3957 *
3958 * Send snapshot:
3959 *
3960 * . (ino 256)
3961 * |----- testdir_2/ (ino 259)
3962 * | |----- a (ino 260)
3963 * |
3964 * |----- testdir (ino 257)
3965 * |----- b (ino 257)
3966 * |----- b2 (ino 258)
3967 *
3968 * Processing the new reference for inode 257 with name "b" may happen
3969 * before processing the new reference with name "testdir". If so, we
3970 * must make sure that by the time we send a link command to create the
3971 * hard link "b", inode 259 was already orphanized, since the generated
3972 * path in "valid_path" already contains the orphanized name for 259.
3973 * We are processing inode 257, so only later when processing 259 we do
3974 * the rename operation to change its temporary (orphanized) name to
3975 * "testdir_2".
3976 */
3977 list_for_each_entry(cur, &sctx->new_refs, list) {
3978 ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
3979 if (ret < 0)
3980 goto out;
3981 if (ret == inode_state_will_create)
3982 continue;
3983
3984 /*
3985 * Check if this new ref would overwrite the first ref of another
3986 * unprocessed inode. If yes, orphanize the overwritten inode.
3987 * If we find an overwritten ref that is not the first ref,
3988 * simply unlink it.
3989 */
3990 ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen,
3991 cur->name, cur->name_len,
3992 &ow_inode, &ow_gen, &ow_mode);
3993 if (ret < 0)
3994 goto out;
3995 if (ret) {
3996 ret = is_first_ref(sctx->parent_root,
3997 ow_inode, cur->dir, cur->name,
3998 cur->name_len);
3999 if (ret < 0)
4000 goto out;
4001 if (ret) {
4002 struct name_cache_entry *nce;
4003 struct waiting_dir_move *wdm;
4004
4005 if (orphanized_dir) {
4006 ret = refresh_ref_path(sctx, cur);
4007 if (ret < 0)
4008 goto out;
4009 }
4010
4011 ret = orphanize_inode(sctx, ow_inode, ow_gen,
4012 cur->full_path);
4013 if (ret < 0)
4014 goto out;
4015 if (S_ISDIR(ow_mode))
4016 orphanized_dir = true;
4017
4018 /*
4019 * If ow_inode has its rename operation delayed
4020 * make sure that its orphanized name is used in
4021 * the source path when performing its rename
4022 * operation.
4023 */
4024 if (is_waiting_for_move(sctx, ow_inode)) {
4025 wdm = get_waiting_dir_move(sctx,
4026 ow_inode);
4027 ASSERT(wdm);
4028 wdm->orphanized = true;
4029 }
4030
4031 /*
4032 * Make sure we clear our orphanized inode's
4033 * name from the name cache. This is because the
4034 * inode ow_inode might be an ancestor of some
4035 * other inode that will be orphanized as well
4036 * later and has an inode number greater than
4037 * sctx->send_progress. We need to prevent
4038 * future name lookups from using the old name
4039 * and get instead the orphan name.
4040 */
4041 nce = name_cache_search(sctx, ow_inode, ow_gen);
4042 if (nce) {
4043 name_cache_delete(sctx, nce);
4044 kfree(nce);
4045 }
4046
4047 /*
4048 * ow_inode might currently be an ancestor of
4049 * cur_ino, therefore compute valid_path (the
4050 * current path of cur_ino) again because it
4051 * might contain the pre-orphanization name of
4052 * ow_inode, which is no longer valid.
4053 */
4054 ret = is_ancestor(sctx->parent_root,
4055 ow_inode, ow_gen,
4056 sctx->cur_ino, NULL);
4057 if (ret > 0) {
4058 orphanized_ancestor = true;
4059 fs_path_reset(valid_path);
4060 ret = get_cur_path(sctx, sctx->cur_ino,
4061 sctx->cur_inode_gen,
4062 valid_path);
4063 }
4064 if (ret < 0)
4065 goto out;
4066 } else {
4067 /*
4068 * If we previously orphanized a directory that
4069 * collided with a new reference that we already
4070 * processed, recompute the current path because
4071 * that directory may be part of the path.
4072 */
4073 if (orphanized_dir) {
4074 ret = refresh_ref_path(sctx, cur);
4075 if (ret < 0)
4076 goto out;
4077 }
4078 ret = send_unlink(sctx, cur->full_path);
4079 if (ret < 0)
4080 goto out;
4081 }
4082 }
4083
4084 }
4085
4086 list_for_each_entry(cur, &sctx->new_refs, list) {
4087 /*
4088 * We may have refs where the parent directory does not exist
4089 * yet. This happens if the parent directories inum is higher
4090 * than the current inum. To handle this case, we create the
4091 * parent directory out of order. But we need to check if this
4092 * did already happen before due to other refs in the same dir.
4093 */
4094 ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
4095 if (ret < 0)
4096 goto out;
4097 if (ret == inode_state_will_create) {
4098 ret = 0;
4099 /*
4100 * First check if any of the current inodes refs did
4101 * already create the dir.
4102 */
4103 list_for_each_entry(cur2, &sctx->new_refs, list) {
4104 if (cur == cur2)
4105 break;
4106 if (cur2->dir == cur->dir) {
4107 ret = 1;
4108 break;
4109 }
4110 }
4111
4112 /*
4113 * If that did not happen, check if a previous inode
4114 * did already create the dir.
4115 */
4116 if (!ret)
4117 ret = did_create_dir(sctx, cur->dir);
4118 if (ret < 0)
4119 goto out;
4120 if (!ret) {
4121 ret = send_create_inode(sctx, cur->dir);
4122 if (ret < 0)
4123 goto out;
4124 }
4125 }
4126
4127 if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root) {
4128 ret = wait_for_dest_dir_move(sctx, cur, is_orphan);
4129 if (ret < 0)
4130 goto out;
4131 if (ret == 1) {
4132 can_rename = false;
4133 *pending_move = 1;
4134 }
4135 }
4136
4137 if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root &&
4138 can_rename) {
4139 ret = wait_for_parent_move(sctx, cur, is_orphan);
4140 if (ret < 0)
4141 goto out;
4142 if (ret == 1) {
4143 can_rename = false;
4144 *pending_move = 1;
4145 }
4146 }
4147
4148 /*
4149 * link/move the ref to the new place. If we have an orphan
4150 * inode, move it and update valid_path. If not, link or move
4151 * it depending on the inode mode.
4152 */
4153 if (is_orphan && can_rename) {
4154 ret = send_rename(sctx, valid_path, cur->full_path);
4155 if (ret < 0)
4156 goto out;
4157 is_orphan = 0;
4158 ret = fs_path_copy(valid_path, cur->full_path);
4159 if (ret < 0)
4160 goto out;
4161 } else if (can_rename) {
4162 if (S_ISDIR(sctx->cur_inode_mode)) {
4163 /*
4164 * Dirs can't be linked, so move it. For moved
4165 * dirs, we always have one new and one deleted
4166 * ref. The deleted ref is ignored later.
4167 */
4168 ret = send_rename(sctx, valid_path,
4169 cur->full_path);
4170 if (!ret)
4171 ret = fs_path_copy(valid_path,
4172 cur->full_path);
4173 if (ret < 0)
4174 goto out;
4175 } else {
4176 /*
4177 * We might have previously orphanized an inode
4178 * which is an ancestor of our current inode,
4179 * so our reference's full path, which was
4180 * computed before any such orphanizations, must
4181 * be updated.
4182 */
4183 if (orphanized_dir) {
4184 ret = update_ref_path(sctx, cur);
4185 if (ret < 0)
4186 goto out;
4187 }
4188 ret = send_link(sctx, cur->full_path,
4189 valid_path);
4190 if (ret < 0)
4191 goto out;
4192 }
4193 }
4194 ret = dup_ref(cur, &check_dirs);
4195 if (ret < 0)
4196 goto out;
4197 }
4198
4199 if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) {
4200 /*
4201 * Check if we can already rmdir the directory. If not,
4202 * orphanize it. For every dir item inside that gets deleted
4203 * later, we do this check again and rmdir it then if possible.
4204 * See the use of check_dirs for more details.
4205 */
4206 ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_inode_gen,
4207 sctx->cur_ino);
4208 if (ret < 0)
4209 goto out;
4210 if (ret) {
4211 ret = send_rmdir(sctx, valid_path);
4212 if (ret < 0)
4213 goto out;
4214 } else if (!is_orphan) {
4215 ret = orphanize_inode(sctx, sctx->cur_ino,
4216 sctx->cur_inode_gen, valid_path);
4217 if (ret < 0)
4218 goto out;
4219 is_orphan = 1;
4220 }
4221
4222 list_for_each_entry(cur, &sctx->deleted_refs, list) {
4223 ret = dup_ref(cur, &check_dirs);
4224 if (ret < 0)
4225 goto out;
4226 }
4227 } else if (S_ISDIR(sctx->cur_inode_mode) &&
4228 !list_empty(&sctx->deleted_refs)) {
4229 /*
4230 * We have a moved dir. Add the old parent to check_dirs
4231 */
4232 cur = list_entry(sctx->deleted_refs.next, struct recorded_ref,
4233 list);
4234 ret = dup_ref(cur, &check_dirs);
4235 if (ret < 0)
4236 goto out;
4237 } else if (!S_ISDIR(sctx->cur_inode_mode)) {
4238 /*
4239 * We have a non dir inode. Go through all deleted refs and
4240 * unlink them if they were not already overwritten by other
4241 * inodes.
4242 */
4243 list_for_each_entry(cur, &sctx->deleted_refs, list) {
4244 ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen,
4245 sctx->cur_ino, sctx->cur_inode_gen,
4246 cur->name, cur->name_len);
4247 if (ret < 0)
4248 goto out;
4249 if (!ret) {
4250 /*
4251 * If we orphanized any ancestor before, we need
4252 * to recompute the full path for deleted names,
4253 * since any such path was computed before we
4254 * processed any references and orphanized any
4255 * ancestor inode.
4256 */
4257 if (orphanized_ancestor) {
4258 ret = update_ref_path(sctx, cur);
4259 if (ret < 0)
4260 goto out;
4261 }
4262 ret = send_unlink(sctx, cur->full_path);
4263 if (ret < 0)
4264 goto out;
4265 }
4266 ret = dup_ref(cur, &check_dirs);
4267 if (ret < 0)
4268 goto out;
4269 }
4270 /*
4271 * If the inode is still orphan, unlink the orphan. This may
4272 * happen when a previous inode did overwrite the first ref
4273 * of this inode and no new refs were added for the current
4274 * inode. Unlinking does not mean that the inode is deleted in
4275 * all cases. There may still be links to this inode in other
4276 * places.
4277 */
4278 if (is_orphan) {
4279 ret = send_unlink(sctx, valid_path);
4280 if (ret < 0)
4281 goto out;
4282 }
4283 }
4284
4285 /*
4286 * We did collect all parent dirs where cur_inode was once located. We
4287 * now go through all these dirs and check if they are pending for
4288 * deletion and if it's finally possible to perform the rmdir now.
4289 * We also update the inode stats of the parent dirs here.
4290 */
4291 list_for_each_entry(cur, &check_dirs, list) {
4292 /*
4293 * In case we had refs into dirs that were not processed yet,
4294 * we don't need to do the utime and rmdir logic for these dirs.
4295 * The dir will be processed later.
4296 */
4297 if (cur->dir > sctx->cur_ino)
4298 continue;
4299
4300 ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
4301 if (ret < 0)
4302 goto out;
4303
4304 if (ret == inode_state_did_create ||
4305 ret == inode_state_no_change) {
4306 /* TODO delayed utimes */
4307 ret = send_utimes(sctx, cur->dir, cur->dir_gen);
4308 if (ret < 0)
4309 goto out;
4310 } else if (ret == inode_state_did_delete &&
4311 cur->dir != last_dir_ino_rm) {
4312 ret = can_rmdir(sctx, cur->dir, cur->dir_gen,
4313 sctx->cur_ino);
4314 if (ret < 0)
4315 goto out;
4316 if (ret) {
4317 ret = get_cur_path(sctx, cur->dir,
4318 cur->dir_gen, valid_path);
4319 if (ret < 0)
4320 goto out;
4321 ret = send_rmdir(sctx, valid_path);
4322 if (ret < 0)
4323 goto out;
4324 last_dir_ino_rm = cur->dir;
4325 }
4326 }
4327 }
4328
4329 ret = 0;
4330
4331 out:
4332 __free_recorded_refs(&check_dirs);
4333 free_recorded_refs(sctx);
4334 fs_path_free(valid_path);
4335 return ret;
4336 }
4337
4338 static int record_ref(struct btrfs_root *root, u64 dir, struct fs_path *name,
4339 void *ctx, struct list_head *refs)
4340 {
4341 int ret = 0;
4342 struct send_ctx *sctx = ctx;
4343 struct fs_path *p;
4344 u64 gen;
4345
4346 p = fs_path_alloc();
4347 if (!p)
4348 return -ENOMEM;
4349
4350 ret = get_inode_info(root, dir, NULL, &gen, NULL, NULL,
4351 NULL, NULL);
4352 if (ret < 0)
4353 goto out;
4354
4355 ret = get_cur_path(sctx, dir, gen, p);
4356 if (ret < 0)
4357 goto out;
4358 ret = fs_path_add_path(p, name);
4359 if (ret < 0)
4360 goto out;
4361
4362 ret = __record_ref(refs, dir, gen, p);
4363
4364 out:
4365 if (ret)
4366 fs_path_free(p);
4367 return ret;
4368 }
4369
4370 static int __record_new_ref(int num, u64 dir, int index,
4371 struct fs_path *name,
4372 void *ctx)
4373 {
4374 struct send_ctx *sctx = ctx;
4375 return record_ref(sctx->send_root, dir, name, ctx, &sctx->new_refs);
4376 }
4377
4378
4379 static int __record_deleted_ref(int num, u64 dir, int index,
4380 struct fs_path *name,
4381 void *ctx)
4382 {
4383 struct send_ctx *sctx = ctx;
4384 return record_ref(sctx->parent_root, dir, name, ctx,
4385 &sctx->deleted_refs);
4386 }
4387
4388 static int record_new_ref(struct send_ctx *sctx)
4389 {
4390 int ret;
4391
4392 ret = iterate_inode_ref(sctx->send_root, sctx->left_path,
4393 sctx->cmp_key, 0, __record_new_ref, sctx);
4394 if (ret < 0)
4395 goto out;
4396 ret = 0;
4397
4398 out:
4399 return ret;
4400 }
4401
4402 static int record_deleted_ref(struct send_ctx *sctx)
4403 {
4404 int ret;
4405
4406 ret = iterate_inode_ref(sctx->parent_root, sctx->right_path,
4407 sctx->cmp_key, 0, __record_deleted_ref, sctx);
4408 if (ret < 0)
4409 goto out;
4410 ret = 0;
4411
4412 out:
4413 return ret;
4414 }
4415
4416 struct find_ref_ctx {
4417 u64 dir;
4418 u64 dir_gen;
4419 struct btrfs_root *root;
4420 struct fs_path *name;
4421 int found_idx;
4422 };
4423
4424 static int __find_iref(int num, u64 dir, int index,
4425 struct fs_path *name,
4426 void *ctx_)
4427 {
4428 struct find_ref_ctx *ctx = ctx_;
4429 u64 dir_gen;
4430 int ret;
4431
4432 if (dir == ctx->dir && fs_path_len(name) == fs_path_len(ctx->name) &&
4433 strncmp(name->start, ctx->name->start, fs_path_len(name)) == 0) {
4434 /*
4435 * To avoid doing extra lookups we'll only do this if everything
4436 * else matches.
4437 */
4438 ret = get_inode_info(ctx->root, dir, NULL, &dir_gen, NULL,
4439 NULL, NULL, NULL);
4440 if (ret)
4441 return ret;
4442 if (dir_gen != ctx->dir_gen)
4443 return 0;
4444 ctx->found_idx = num;
4445 return 1;
4446 }
4447 return 0;
4448 }
4449
4450 static int find_iref(struct btrfs_root *root,
4451 struct btrfs_path *path,
4452 struct btrfs_key *key,
4453 u64 dir, u64 dir_gen, struct fs_path *name)
4454 {
4455 int ret;
4456 struct find_ref_ctx ctx;
4457
4458 ctx.dir = dir;
4459 ctx.name = name;
4460 ctx.dir_gen = dir_gen;
4461 ctx.found_idx = -1;
4462 ctx.root = root;
4463
4464 ret = iterate_inode_ref(root, path, key, 0, __find_iref, &ctx);
4465 if (ret < 0)
4466 return ret;
4467
4468 if (ctx.found_idx == -1)
4469 return -ENOENT;
4470
4471 return ctx.found_idx;
4472 }
4473
4474 static int __record_changed_new_ref(int num, u64 dir, int index,
4475 struct fs_path *name,
4476 void *ctx)
4477 {
4478 u64 dir_gen;
4479 int ret;
4480 struct send_ctx *sctx = ctx;
4481
4482 ret = get_inode_info(sctx->send_root, dir, NULL, &dir_gen, NULL,
4483 NULL, NULL, NULL);
4484 if (ret)
4485 return ret;
4486
4487 ret = find_iref(sctx->parent_root, sctx->right_path,
4488 sctx->cmp_key, dir, dir_gen, name);
4489 if (ret == -ENOENT)
4490 ret = __record_new_ref(num, dir, index, name, sctx);
4491 else if (ret > 0)
4492 ret = 0;
4493
4494 return ret;
4495 }
4496
4497 static int __record_changed_deleted_ref(int num, u64 dir, int index,
4498 struct fs_path *name,
4499 void *ctx)
4500 {
4501 u64 dir_gen;
4502 int ret;
4503 struct send_ctx *sctx = ctx;
4504
4505 ret = get_inode_info(sctx->parent_root, dir, NULL, &dir_gen, NULL,
4506 NULL, NULL, NULL);
4507 if (ret)
4508 return ret;
4509
4510 ret = find_iref(sctx->send_root, sctx->left_path, sctx->cmp_key,
4511 dir, dir_gen, name);
4512 if (ret == -ENOENT)
4513 ret = __record_deleted_ref(num, dir, index, name, sctx);
4514 else if (ret > 0)
4515 ret = 0;
4516
4517 return ret;
4518 }
4519
4520 static int record_changed_ref(struct send_ctx *sctx)
4521 {
4522 int ret = 0;
4523
4524 ret = iterate_inode_ref(sctx->send_root, sctx->left_path,
4525 sctx->cmp_key, 0, __record_changed_new_ref, sctx);
4526 if (ret < 0)
4527 goto out;
4528 ret = iterate_inode_ref(sctx->parent_root, sctx->right_path,
4529 sctx->cmp_key, 0, __record_changed_deleted_ref, sctx);
4530 if (ret < 0)
4531 goto out;
4532 ret = 0;
4533
4534 out:
4535 return ret;
4536 }
4537
4538 /*
4539 * Record and process all refs at once. Needed when an inode changes the
4540 * generation number, which means that it was deleted and recreated.
4541 */
4542 static int process_all_refs(struct send_ctx *sctx,
4543 enum btrfs_compare_tree_result cmd)
4544 {
4545 int ret;
4546 struct btrfs_root *root;
4547 struct btrfs_path *path;
4548 struct btrfs_key key;
4549 struct btrfs_key found_key;
4550 struct extent_buffer *eb;
4551 int slot;
4552 iterate_inode_ref_t cb;
4553 int pending_move = 0;
4554
4555 path = alloc_path_for_send();
4556 if (!path)
4557 return -ENOMEM;
4558
4559 if (cmd == BTRFS_COMPARE_TREE_NEW) {
4560 root = sctx->send_root;
4561 cb = __record_new_ref;
4562 } else if (cmd == BTRFS_COMPARE_TREE_DELETED) {
4563 root = sctx->parent_root;
4564 cb = __record_deleted_ref;
4565 } else {
4566 btrfs_err(sctx->send_root->fs_info,
4567 "Wrong command %d in process_all_refs", cmd);
4568 ret = -EINVAL;
4569 goto out;
4570 }
4571
4572 key.objectid = sctx->cmp_key->objectid;
4573 key.type = BTRFS_INODE_REF_KEY;
4574 key.offset = 0;
4575 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4576 if (ret < 0)
4577 goto out;
4578
4579 while (1) {
4580 eb = path->nodes[0];
4581 slot = path->slots[0];
4582 if (slot >= btrfs_header_nritems(eb)) {
4583 ret = btrfs_next_leaf(root, path);
4584 if (ret < 0)
4585 goto out;
4586 else if (ret > 0)
4587 break;
4588 continue;
4589 }
4590
4591 btrfs_item_key_to_cpu(eb, &found_key, slot);
4592
4593 if (found_key.objectid != key.objectid ||
4594 (found_key.type != BTRFS_INODE_REF_KEY &&
4595 found_key.type != BTRFS_INODE_EXTREF_KEY))
4596 break;
4597
4598 ret = iterate_inode_ref(root, path, &found_key, 0, cb, sctx);
4599 if (ret < 0)
4600 goto out;
4601
4602 path->slots[0]++;
4603 }
4604 btrfs_release_path(path);
4605
4606 /*
4607 * We don't actually care about pending_move as we are simply
4608 * re-creating this inode and will be rename'ing it into place once we
4609 * rename the parent directory.
4610 */
4611 ret = process_recorded_refs(sctx, &pending_move);
4612 out:
4613 btrfs_free_path(path);
4614 return ret;
4615 }
4616
4617 static int send_set_xattr(struct send_ctx *sctx,
4618 struct fs_path *path,
4619 const char *name, int name_len,
4620 const char *data, int data_len)
4621 {
4622 int ret = 0;
4623
4624 ret = begin_cmd(sctx, BTRFS_SEND_C_SET_XATTR);
4625 if (ret < 0)
4626 goto out;
4627
4628 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
4629 TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
4630 TLV_PUT(sctx, BTRFS_SEND_A_XATTR_DATA, data, data_len);
4631
4632 ret = send_cmd(sctx);
4633
4634 tlv_put_failure:
4635 out:
4636 return ret;
4637 }
4638
4639 static int send_remove_xattr(struct send_ctx *sctx,
4640 struct fs_path *path,
4641 const char *name, int name_len)
4642 {
4643 int ret = 0;
4644
4645 ret = begin_cmd(sctx, BTRFS_SEND_C_REMOVE_XATTR);
4646 if (ret < 0)
4647 goto out;
4648
4649 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
4650 TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
4651
4652 ret = send_cmd(sctx);
4653
4654 tlv_put_failure:
4655 out:
4656 return ret;
4657 }
4658
4659 static int __process_new_xattr(int num, struct btrfs_key *di_key,
4660 const char *name, int name_len,
4661 const char *data, int data_len,
4662 u8 type, void *ctx)
4663 {
4664 int ret;
4665 struct send_ctx *sctx = ctx;
4666 struct fs_path *p;
4667 struct posix_acl_xattr_header dummy_acl;
4668
4669 /* Capabilities are emitted by finish_inode_if_needed */
4670 if (!strncmp(name, XATTR_NAME_CAPS, name_len))
4671 return 0;
4672
4673 p = fs_path_alloc();
4674 if (!p)
4675 return -ENOMEM;
4676
4677 /*
4678 * This hack is needed because empty acls are stored as zero byte
4679 * data in xattrs. Problem with that is, that receiving these zero byte
4680 * acls will fail later. To fix this, we send a dummy acl list that
4681 * only contains the version number and no entries.
4682 */
4683 if (!strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS, name_len) ||
4684 !strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT, name_len)) {
4685 if (data_len == 0) {
4686 dummy_acl.a_version =
4687 cpu_to_le32(POSIX_ACL_XATTR_VERSION);
4688 data = (char *)&dummy_acl;
4689 data_len = sizeof(dummy_acl);
4690 }
4691 }
4692
4693 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
4694 if (ret < 0)
4695 goto out;
4696
4697 ret = send_set_xattr(sctx, p, name, name_len, data, data_len);
4698
4699 out:
4700 fs_path_free(p);
4701 return ret;
4702 }
4703
4704 static int __process_deleted_xattr(int num, struct btrfs_key *di_key,
4705 const char *name, int name_len,
4706 const char *data, int data_len,
4707 u8 type, void *ctx)
4708 {
4709 int ret;
4710 struct send_ctx *sctx = ctx;
4711 struct fs_path *p;
4712
4713 p = fs_path_alloc();
4714 if (!p)
4715 return -ENOMEM;
4716
4717 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
4718 if (ret < 0)
4719 goto out;
4720
4721 ret = send_remove_xattr(sctx, p, name, name_len);
4722
4723 out:
4724 fs_path_free(p);
4725 return ret;
4726 }
4727
4728 static int process_new_xattr(struct send_ctx *sctx)
4729 {
4730 int ret = 0;
4731
4732 ret = iterate_dir_item(sctx->send_root, sctx->left_path,
4733 __process_new_xattr, sctx);
4734
4735 return ret;
4736 }
4737
4738 static int process_deleted_xattr(struct send_ctx *sctx)
4739 {
4740 return iterate_dir_item(sctx->parent_root, sctx->right_path,
4741 __process_deleted_xattr, sctx);
4742 }
4743
4744 struct find_xattr_ctx {
4745 const char *name;
4746 int name_len;
4747 int found_idx;
4748 char *found_data;
4749 int found_data_len;
4750 };
4751
4752 static int __find_xattr(int num, struct btrfs_key *di_key,
4753 const char *name, int name_len,
4754 const char *data, int data_len,
4755 u8 type, void *vctx)
4756 {
4757 struct find_xattr_ctx *ctx = vctx;
4758
4759 if (name_len == ctx->name_len &&
4760 strncmp(name, ctx->name, name_len) == 0) {
4761 ctx->found_idx = num;
4762 ctx->found_data_len = data_len;
4763 ctx->found_data = kmemdup(data, data_len, GFP_KERNEL);
4764 if (!ctx->found_data)
4765 return -ENOMEM;
4766 return 1;
4767 }
4768 return 0;
4769 }
4770
4771 static int find_xattr(struct btrfs_root *root,
4772 struct btrfs_path *path,
4773 struct btrfs_key *key,
4774 const char *name, int name_len,
4775 char **data, int *data_len)
4776 {
4777 int ret;
4778 struct find_xattr_ctx ctx;
4779
4780 ctx.name = name;
4781 ctx.name_len = name_len;
4782 ctx.found_idx = -1;
4783 ctx.found_data = NULL;
4784 ctx.found_data_len = 0;
4785
4786 ret = iterate_dir_item(root, path, __find_xattr, &ctx);
4787 if (ret < 0)
4788 return ret;
4789
4790 if (ctx.found_idx == -1)
4791 return -ENOENT;
4792 if (data) {
4793 *data = ctx.found_data;
4794 *data_len = ctx.found_data_len;
4795 } else {
4796 kfree(ctx.found_data);
4797 }
4798 return ctx.found_idx;
4799 }
4800
4801
4802 static int __process_changed_new_xattr(int num, struct btrfs_key *di_key,
4803 const char *name, int name_len,
4804 const char *data, int data_len,
4805 u8 type, void *ctx)
4806 {
4807 int ret;
4808 struct send_ctx *sctx = ctx;
4809 char *found_data = NULL;
4810 int found_data_len = 0;
4811
4812 ret = find_xattr(sctx->parent_root, sctx->right_path,
4813 sctx->cmp_key, name, name_len, &found_data,
4814 &found_data_len);
4815 if (ret == -ENOENT) {
4816 ret = __process_new_xattr(num, di_key, name, name_len, data,
4817 data_len, type, ctx);
4818 } else if (ret >= 0) {
4819 if (data_len != found_data_len ||
4820 memcmp(data, found_data, data_len)) {
4821 ret = __process_new_xattr(num, di_key, name, name_len,
4822 data, data_len, type, ctx);
4823 } else {
4824 ret = 0;
4825 }
4826 }
4827
4828 kfree(found_data);
4829 return ret;
4830 }
4831
4832 static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key,
4833 const char *name, int name_len,
4834 const char *data, int data_len,
4835 u8 type, void *ctx)
4836 {
4837 int ret;
4838 struct send_ctx *sctx = ctx;
4839
4840 ret = find_xattr(sctx->send_root, sctx->left_path, sctx->cmp_key,
4841 name, name_len, NULL, NULL);
4842 if (ret == -ENOENT)
4843 ret = __process_deleted_xattr(num, di_key, name, name_len, data,
4844 data_len, type, ctx);
4845 else if (ret >= 0)
4846 ret = 0;
4847
4848 return ret;
4849 }
4850
4851 static int process_changed_xattr(struct send_ctx *sctx)
4852 {
4853 int ret = 0;
4854
4855 ret = iterate_dir_item(sctx->send_root, sctx->left_path,
4856 __process_changed_new_xattr, sctx);
4857 if (ret < 0)
4858 goto out;
4859 ret = iterate_dir_item(sctx->parent_root, sctx->right_path,
4860 __process_changed_deleted_xattr, sctx);
4861
4862 out:
4863 return ret;
4864 }
4865
4866 static int process_all_new_xattrs(struct send_ctx *sctx)
4867 {
4868 int ret;
4869 struct btrfs_root *root;
4870 struct btrfs_path *path;
4871 struct btrfs_key key;
4872 struct btrfs_key found_key;
4873 struct extent_buffer *eb;
4874 int slot;
4875
4876 path = alloc_path_for_send();
4877 if (!path)
4878 return -ENOMEM;
4879
4880 root = sctx->send_root;
4881
4882 key.objectid = sctx->cmp_key->objectid;
4883 key.type = BTRFS_XATTR_ITEM_KEY;
4884 key.offset = 0;
4885 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4886 if (ret < 0)
4887 goto out;
4888
4889 while (1) {
4890 eb = path->nodes[0];
4891 slot = path->slots[0];
4892 if (slot >= btrfs_header_nritems(eb)) {
4893 ret = btrfs_next_leaf(root, path);
4894 if (ret < 0) {
4895 goto out;
4896 } else if (ret > 0) {
4897 ret = 0;
4898 break;
4899 }
4900 continue;
4901 }
4902
4903 btrfs_item_key_to_cpu(eb, &found_key, slot);
4904 if (found_key.objectid != key.objectid ||
4905 found_key.type != key.type) {
4906 ret = 0;
4907 goto out;
4908 }
4909
4910 ret = iterate_dir_item(root, path, __process_new_xattr, sctx);
4911 if (ret < 0)
4912 goto out;
4913
4914 path->slots[0]++;
4915 }
4916
4917 out:
4918 btrfs_free_path(path);
4919 return ret;
4920 }
4921
4922 static inline u64 max_send_read_size(const struct send_ctx *sctx)
4923 {
4924 return sctx->send_max_size - SZ_16K;
4925 }
4926
4927 static int put_data_header(struct send_ctx *sctx, u32 len)
4928 {
4929 struct btrfs_tlv_header *hdr;
4930
4931 if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len)
4932 return -EOVERFLOW;
4933 hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size);
4934 put_unaligned_le16(BTRFS_SEND_A_DATA, &hdr->tlv_type);
4935 put_unaligned_le16(len, &hdr->tlv_len);
4936 sctx->send_size += sizeof(*hdr);
4937 return 0;
4938 }
4939
4940 static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
4941 {
4942 struct btrfs_root *root = sctx->send_root;
4943 struct btrfs_fs_info *fs_info = root->fs_info;
4944 struct inode *inode;
4945 struct page *page;
4946 pgoff_t index = offset >> PAGE_SHIFT;
4947 pgoff_t last_index;
4948 unsigned pg_offset = offset_in_page(offset);
4949 int ret;
4950
4951 ret = put_data_header(sctx, len);
4952 if (ret)
4953 return ret;
4954
4955 inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root);
4956 if (IS_ERR(inode))
4957 return PTR_ERR(inode);
4958
4959 last_index = (offset + len - 1) >> PAGE_SHIFT;
4960
4961 /* initial readahead */
4962 memset(&sctx->ra, 0, sizeof(struct file_ra_state));
4963 file_ra_state_init(&sctx->ra, inode->i_mapping);
4964
4965 while (index <= last_index) {
4966 unsigned cur_len = min_t(unsigned, len,
4967 PAGE_SIZE - pg_offset);
4968
4969 page = find_lock_page(inode->i_mapping, index);
4970 if (!page) {
4971 page_cache_sync_readahead(inode->i_mapping, &sctx->ra,
4972 NULL, index, last_index + 1 - index);
4973
4974 page = find_or_create_page(inode->i_mapping, index,
4975 GFP_KERNEL);
4976 if (!page) {
4977 ret = -ENOMEM;
4978 break;
4979 }
4980 }
4981
4982 if (PageReadahead(page)) {
4983 page_cache_async_readahead(inode->i_mapping, &sctx->ra,
4984 NULL, page, index, last_index + 1 - index);
4985 }
4986
4987 if (!PageUptodate(page)) {
4988 btrfs_readpage(NULL, page);
4989 lock_page(page);
4990 if (!PageUptodate(page)) {
4991 unlock_page(page);
4992 put_page(page);
4993 ret = -EIO;
4994 break;
4995 }
4996 }
4997
4998 memcpy_from_page(sctx->send_buf + sctx->send_size, page,
4999 pg_offset, cur_len);
5000 unlock_page(page);
5001 put_page(page);
5002 index++;
5003 pg_offset = 0;
5004 len -= cur_len;
5005 sctx->send_size += cur_len;
5006 }
5007 iput(inode);
5008 return ret;
5009 }
5010
5011 /*
5012 * Read some bytes from the current inode/file and send a write command to
5013 * user space.
5014 */
5015 static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
5016 {
5017 struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
5018 int ret = 0;
5019 struct fs_path *p;
5020
5021 p = fs_path_alloc();
5022 if (!p)
5023 return -ENOMEM;
5024
5025 btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len);
5026
5027 ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
5028 if (ret < 0)
5029 goto out;
5030
5031 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5032 if (ret < 0)
5033 goto out;
5034
5035 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
5036 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5037 ret = put_file_data(sctx, offset, len);
5038 if (ret < 0)
5039 goto out;
5040
5041 ret = send_cmd(sctx);
5042
5043 tlv_put_failure:
5044 out:
5045 fs_path_free(p);
5046 return ret;
5047 }
5048
5049 /*
5050 * Send a clone command to user space.
5051 */
5052 static int send_clone(struct send_ctx *sctx,
5053 u64 offset, u32 len,
5054 struct clone_root *clone_root)
5055 {
5056 int ret = 0;
5057 struct fs_path *p;
5058 u64 gen;
5059
5060 btrfs_debug(sctx->send_root->fs_info,
5061 "send_clone offset=%llu, len=%d, clone_root=%llu, clone_inode=%llu, clone_offset=%llu",
5062 offset, len, clone_root->root->root_key.objectid,
5063 clone_root->ino, clone_root->offset);
5064
5065 p = fs_path_alloc();
5066 if (!p)
5067 return -ENOMEM;
5068
5069 ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE);
5070 if (ret < 0)
5071 goto out;
5072
5073 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5074 if (ret < 0)
5075 goto out;
5076
5077 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5078 TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len);
5079 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
5080
5081 if (clone_root->root == sctx->send_root) {
5082 ret = get_inode_info(sctx->send_root, clone_root->ino, NULL,
5083 &gen, NULL, NULL, NULL, NULL);
5084 if (ret < 0)
5085 goto out;
5086 ret = get_cur_path(sctx, clone_root->ino, gen, p);
5087 } else {
5088 ret = get_inode_path(clone_root->root, clone_root->ino, p);
5089 }
5090 if (ret < 0)
5091 goto out;
5092
5093 /*
5094 * If the parent we're using has a received_uuid set then use that as
5095 * our clone source as that is what we will look for when doing a
5096 * receive.
5097 *
5098 * This covers the case that we create a snapshot off of a received
5099 * subvolume and then use that as the parent and try to receive on a
5100 * different host.
5101 */
5102 if (!btrfs_is_empty_uuid(clone_root->root->root_item.received_uuid))
5103 TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
5104 clone_root->root->root_item.received_uuid);
5105 else
5106 TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
5107 clone_root->root->root_item.uuid);
5108 TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
5109 btrfs_root_ctransid(&clone_root->root->root_item));
5110 TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p);
5111 TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET,
5112 clone_root->offset);
5113
5114 ret = send_cmd(sctx);
5115
5116 tlv_put_failure:
5117 out:
5118 fs_path_free(p);
5119 return ret;
5120 }
5121
5122 /*
5123 * Send an update extent command to user space.
5124 */
5125 static int send_update_extent(struct send_ctx *sctx,
5126 u64 offset, u32 len)
5127 {
5128 int ret = 0;
5129 struct fs_path *p;
5130
5131 p = fs_path_alloc();
5132 if (!p)
5133 return -ENOMEM;
5134
5135 ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT);
5136 if (ret < 0)
5137 goto out;
5138
5139 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5140 if (ret < 0)
5141 goto out;
5142
5143 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
5144 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5145 TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len);
5146
5147 ret = send_cmd(sctx);
5148
5149 tlv_put_failure:
5150 out:
5151 fs_path_free(p);
5152 return ret;
5153 }
5154
5155 static int send_hole(struct send_ctx *sctx, u64 end)
5156 {
5157 struct fs_path *p = NULL;
5158 u64 read_size = max_send_read_size(sctx);
5159 u64 offset = sctx->cur_inode_last_extent;
5160 int ret = 0;
5161
5162 /*
5163 * A hole that starts at EOF or beyond it. Since we do not yet support
5164 * fallocate (for extent preallocation and hole punching), sending a
5165 * write of zeroes starting at EOF or beyond would later require issuing
5166 * a truncate operation which would undo the write and achieve nothing.
5167 */
5168 if (offset >= sctx->cur_inode_size)
5169 return 0;
5170
5171 /*
5172 * Don't go beyond the inode's i_size due to prealloc extents that start
5173 * after the i_size.
5174 */
5175 end = min_t(u64, end, sctx->cur_inode_size);
5176
5177 if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
5178 return send_update_extent(sctx, offset, end - offset);
5179
5180 p = fs_path_alloc();
5181 if (!p)
5182 return -ENOMEM;
5183 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5184 if (ret < 0)
5185 goto tlv_put_failure;
5186 while (offset < end) {
5187 u64 len = min(end - offset, read_size);
5188
5189 ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
5190 if (ret < 0)
5191 break;
5192 TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
5193 TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5194 ret = put_data_header(sctx, len);
5195 if (ret < 0)
5196 break;
5197 memset(sctx->send_buf + sctx->send_size, 0, len);
5198 sctx->send_size += len;
5199 ret = send_cmd(sctx);
5200 if (ret < 0)
5201 break;
5202 offset += len;
5203 }
5204 sctx->cur_inode_next_write_offset = offset;
5205 tlv_put_failure:
5206 fs_path_free(p);
5207 return ret;
5208 }
5209
5210 static int send_extent_data(struct send_ctx *sctx,
5211 const u64 offset,
5212 const u64 len)
5213 {
5214 u64 read_size = max_send_read_size(sctx);
5215 u64 sent = 0;
5216
5217 if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
5218 return send_update_extent(sctx, offset, len);
5219
5220 while (sent < len) {
5221 u64 size = min(len - sent, read_size);
5222 int ret;
5223
5224 ret = send_write(sctx, offset + sent, size);
5225 if (ret < 0)
5226 return ret;
5227 sent += size;
5228 }
5229 return 0;
5230 }
5231
5232 /*
5233 * Search for a capability xattr related to sctx->cur_ino. If the capability is
5234 * found, call send_set_xattr function to emit it.
5235 *
5236 * Return 0 if there isn't a capability, or when the capability was emitted
5237 * successfully, or < 0 if an error occurred.
5238 */
5239 static int send_capabilities(struct send_ctx *sctx)
5240 {
5241 struct fs_path *fspath = NULL;
5242 struct btrfs_path *path;
5243 struct btrfs_dir_item *di;
5244 struct extent_buffer *leaf;
5245 unsigned long data_ptr;
5246 char *buf = NULL;
5247 int buf_len;
5248 int ret = 0;
5249
5250 path = alloc_path_for_send();
5251 if (!path)
5252 return -ENOMEM;
5253
5254 di = btrfs_lookup_xattr(NULL, sctx->send_root, path, sctx->cur_ino,
5255 XATTR_NAME_CAPS, strlen(XATTR_NAME_CAPS), 0);
5256 if (!di) {
5257 /* There is no xattr for this inode */
5258 goto out;
5259 } else if (IS_ERR(di)) {
5260 ret = PTR_ERR(di);
5261 goto out;
5262 }
5263
5264 leaf = path->nodes[0];
5265 buf_len = btrfs_dir_data_len(leaf, di);
5266
5267 fspath = fs_path_alloc();
5268 buf = kmalloc(buf_len, GFP_KERNEL);
5269 if (!fspath || !buf) {
5270 ret = -ENOMEM;
5271 goto out;
5272 }
5273
5274 ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath);
5275 if (ret < 0)
5276 goto out;
5277
5278 data_ptr = (unsigned long)(di + 1) + btrfs_dir_name_len(leaf, di);
5279 read_extent_buffer(leaf, buf, data_ptr, buf_len);
5280
5281 ret = send_set_xattr(sctx, fspath, XATTR_NAME_CAPS,
5282 strlen(XATTR_NAME_CAPS), buf, buf_len);
5283 out:
5284 kfree(buf);
5285 fs_path_free(fspath);
5286 btrfs_free_path(path);
5287 return ret;
5288 }
5289
5290 static int clone_range(struct send_ctx *sctx,
5291 struct clone_root *clone_root,
5292 const u64 disk_byte,
5293 u64 data_offset,
5294 u64 offset,
5295 u64 len)
5296 {
5297 struct btrfs_path *path;
5298 struct btrfs_key key;
5299 int ret;
5300 u64 clone_src_i_size = 0;
5301
5302 /*
5303 * Prevent cloning from a zero offset with a length matching the sector
5304 * size because in some scenarios this will make the receiver fail.
5305 *
5306 * For example, if in the source filesystem the extent at offset 0
5307 * has a length of sectorsize and it was written using direct IO, then
5308 * it can never be an inline extent (even if compression is enabled).
5309 * Then this extent can be cloned in the original filesystem to a non
5310 * zero file offset, but it may not be possible to clone in the
5311 * destination filesystem because it can be inlined due to compression
5312 * on the destination filesystem (as the receiver's write operations are
5313 * always done using buffered IO). The same happens when the original
5314 * filesystem does not have compression enabled but the destination
5315 * filesystem has.
5316 */
5317 if (clone_root->offset == 0 &&
5318 len == sctx->send_root->fs_info->sectorsize)
5319 return send_extent_data(sctx, offset, len);
5320
5321 path = alloc_path_for_send();
5322 if (!path)
5323 return -ENOMEM;
5324
5325 /*
5326 * There are inodes that have extents that lie behind its i_size. Don't
5327 * accept clones from these extents.
5328 */
5329 ret = __get_inode_info(clone_root->root, path, clone_root->ino,
5330 &clone_src_i_size, NULL, NULL, NULL, NULL, NULL);
5331 btrfs_release_path(path);
5332 if (ret < 0)
5333 goto out;
5334
5335 /*
5336 * We can't send a clone operation for the entire range if we find
5337 * extent items in the respective range in the source file that
5338 * refer to different extents or if we find holes.
5339 * So check for that and do a mix of clone and regular write/copy
5340 * operations if needed.
5341 *
5342 * Example:
5343 *
5344 * mkfs.btrfs -f /dev/sda
5345 * mount /dev/sda /mnt
5346 * xfs_io -f -c "pwrite -S 0xaa 0K 100K" /mnt/foo
5347 * cp --reflink=always /mnt/foo /mnt/bar
5348 * xfs_io -c "pwrite -S 0xbb 50K 50K" /mnt/foo
5349 * btrfs subvolume snapshot -r /mnt /mnt/snap
5350 *
5351 * If when we send the snapshot and we are processing file bar (which
5352 * has a higher inode number than foo) we blindly send a clone operation
5353 * for the [0, 100K[ range from foo to bar, the receiver ends up getting
5354 * a file bar that matches the content of file foo - iow, doesn't match
5355 * the content from bar in the original filesystem.
5356 */
5357 key.objectid = clone_root->ino;
5358 key.type = BTRFS_EXTENT_DATA_KEY;
5359 key.offset = clone_root->offset;
5360 ret = btrfs_search_slot(NULL, clone_root->root, &key, path, 0, 0);
5361 if (ret < 0)
5362 goto out;
5363 if (ret > 0 && path->slots[0] > 0) {
5364 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1);
5365 if (key.objectid == clone_root->ino &&
5366 key.type == BTRFS_EXTENT_DATA_KEY)
5367 path->slots[0]--;
5368 }
5369
5370 while (true) {
5371 struct extent_buffer *leaf = path->nodes[0];
5372 int slot = path->slots[0];
5373 struct btrfs_file_extent_item *ei;
5374 u8 type;
5375 u64 ext_len;
5376 u64 clone_len;
5377 u64 clone_data_offset;
5378
5379 if (slot >= btrfs_header_nritems(leaf)) {
5380 ret = btrfs_next_leaf(clone_root->root, path);
5381 if (ret < 0)
5382 goto out;
5383 else if (ret > 0)
5384 break;
5385 continue;
5386 }
5387
5388 btrfs_item_key_to_cpu(leaf, &key, slot);
5389
5390 /*
5391 * We might have an implicit trailing hole (NO_HOLES feature
5392 * enabled). We deal with it after leaving this loop.
5393 */
5394 if (key.objectid != clone_root->ino ||
5395 key.type != BTRFS_EXTENT_DATA_KEY)
5396 break;
5397
5398 ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5399 type = btrfs_file_extent_type(leaf, ei);
5400 if (type == BTRFS_FILE_EXTENT_INLINE) {
5401 ext_len = btrfs_file_extent_ram_bytes(leaf, ei);
5402 ext_len = PAGE_ALIGN(ext_len);
5403 } else {
5404 ext_len = btrfs_file_extent_num_bytes(leaf, ei);
5405 }
5406
5407 if (key.offset + ext_len <= clone_root->offset)
5408 goto next;
5409
5410 if (key.offset > clone_root->offset) {
5411 /* Implicit hole, NO_HOLES feature enabled. */
5412 u64 hole_len = key.offset - clone_root->offset;
5413
5414 if (hole_len > len)
5415 hole_len = len;
5416 ret = send_extent_data(sctx, offset, hole_len);
5417 if (ret < 0)
5418 goto out;
5419
5420 len -= hole_len;
5421 if (len == 0)
5422 break;
5423 offset += hole_len;
5424 clone_root->offset += hole_len;
5425 data_offset += hole_len;
5426 }
5427
5428 if (key.offset >= clone_root->offset + len)
5429 break;
5430
5431 if (key.offset >= clone_src_i_size)
5432 break;
5433
5434 if (key.offset + ext_len > clone_src_i_size)
5435 ext_len = clone_src_i_size - key.offset;
5436
5437 clone_data_offset = btrfs_file_extent_offset(leaf, ei);
5438 if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte) {
5439 clone_root->offset = key.offset;
5440 if (clone_data_offset < data_offset &&
5441 clone_data_offset + ext_len > data_offset) {
5442 u64 extent_offset;
5443
5444 extent_offset = data_offset - clone_data_offset;
5445 ext_len -= extent_offset;
5446 clone_data_offset += extent_offset;
5447 clone_root->offset += extent_offset;
5448 }
5449 }
5450
5451 clone_len = min_t(u64, ext_len, len);
5452
5453 if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte &&
5454 clone_data_offset == data_offset) {
5455 const u64 src_end = clone_root->offset + clone_len;
5456 const u64 sectorsize = SZ_64K;
5457
5458 /*
5459 * We can't clone the last block, when its size is not
5460 * sector size aligned, into the middle of a file. If we
5461 * do so, the receiver will get a failure (-EINVAL) when
5462 * trying to clone or will silently corrupt the data in
5463 * the destination file if it's on a kernel without the
5464 * fix introduced by commit ac765f83f1397646
5465 * ("Btrfs: fix data corruption due to cloning of eof
5466 * block).
5467 *
5468 * So issue a clone of the aligned down range plus a
5469 * regular write for the eof block, if we hit that case.
5470 *
5471 * Also, we use the maximum possible sector size, 64K,
5472 * because we don't know what's the sector size of the
5473 * filesystem that receives the stream, so we have to
5474 * assume the largest possible sector size.
5475 */
5476 if (src_end == clone_src_i_size &&
5477 !IS_ALIGNED(src_end, sectorsize) &&
5478 offset + clone_len < sctx->cur_inode_size) {
5479 u64 slen;
5480
5481 slen = ALIGN_DOWN(src_end - clone_root->offset,
5482 sectorsize);
5483 if (slen > 0) {
5484 ret = send_clone(sctx, offset, slen,
5485 clone_root);
5486 if (ret < 0)
5487 goto out;
5488 }
5489 ret = send_extent_data(sctx, offset + slen,
5490 clone_len - slen);
5491 } else {
5492 ret = send_clone(sctx, offset, clone_len,
5493 clone_root);
5494 }
5495 } else {
5496 ret = send_extent_data(sctx, offset, clone_len);
5497 }
5498
5499 if (ret < 0)
5500 goto out;
5501
5502 len -= clone_len;
5503 if (len == 0)
5504 break;
5505 offset += clone_len;
5506 clone_root->offset += clone_len;
5507
5508 /*
5509 * If we are cloning from the file we are currently processing,
5510 * and using the send root as the clone root, we must stop once
5511 * the current clone offset reaches the current eof of the file
5512 * at the receiver, otherwise we would issue an invalid clone
5513 * operation (source range going beyond eof) and cause the
5514 * receiver to fail. So if we reach the current eof, bail out
5515 * and fallback to a regular write.
5516 */
5517 if (clone_root->root == sctx->send_root &&
5518 clone_root->ino == sctx->cur_ino &&
5519 clone_root->offset >= sctx->cur_inode_next_write_offset)
5520 break;
5521
5522 data_offset += clone_len;
5523 next:
5524 path->slots[0]++;
5525 }
5526
5527 if (len > 0)
5528 ret = send_extent_data(sctx, offset, len);
5529 else
5530 ret = 0;
5531 out:
5532 btrfs_free_path(path);
5533 return ret;
5534 }
5535
5536 static int send_write_or_clone(struct send_ctx *sctx,
5537 struct btrfs_path *path,
5538 struct btrfs_key *key,
5539 struct clone_root *clone_root)
5540 {
5541 int ret = 0;
5542 u64 offset = key->offset;
5543 u64 end;
5544 u64 bs = sctx->send_root->fs_info->sb->s_blocksize;
5545
5546 end = min_t(u64, btrfs_file_extent_end(path), sctx->cur_inode_size);
5547 if (offset >= end)
5548 return 0;
5549
5550 if (clone_root && IS_ALIGNED(end, bs)) {
5551 struct btrfs_file_extent_item *ei;
5552 u64 disk_byte;
5553 u64 data_offset;
5554
5555 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
5556 struct btrfs_file_extent_item);
5557 disk_byte = btrfs_file_extent_disk_bytenr(path->nodes[0], ei);
5558 data_offset = btrfs_file_extent_offset(path->nodes[0], ei);
5559 ret = clone_range(sctx, clone_root, disk_byte, data_offset,
5560 offset, end - offset);
5561 } else {
5562 ret = send_extent_data(sctx, offset, end - offset);
5563 }
5564 sctx->cur_inode_next_write_offset = end;
5565 return ret;
5566 }
5567
5568 static int is_extent_unchanged(struct send_ctx *sctx,
5569 struct btrfs_path *left_path,
5570 struct btrfs_key *ekey)
5571 {
5572 int ret = 0;
5573 struct btrfs_key key;
5574 struct btrfs_path *path = NULL;
5575 struct extent_buffer *eb;
5576 int slot;
5577 struct btrfs_key found_key;
5578 struct btrfs_file_extent_item *ei;
5579 u64 left_disknr;
5580 u64 right_disknr;
5581 u64 left_offset;
5582 u64 right_offset;
5583 u64 left_offset_fixed;
5584 u64 left_len;
5585 u64 right_len;
5586 u64 left_gen;
5587 u64 right_gen;
5588 u8 left_type;
5589 u8 right_type;
5590
5591 path = alloc_path_for_send();
5592 if (!path)
5593 return -ENOMEM;
5594
5595 eb = left_path->nodes[0];
5596 slot = left_path->slots[0];
5597 ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
5598 left_type = btrfs_file_extent_type(eb, ei);
5599
5600 if (left_type != BTRFS_FILE_EXTENT_REG) {
5601 ret = 0;
5602 goto out;
5603 }
5604 left_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
5605 left_len = btrfs_file_extent_num_bytes(eb, ei);
5606 left_offset = btrfs_file_extent_offset(eb, ei);
5607 left_gen = btrfs_file_extent_generation(eb, ei);
5608
5609 /*
5610 * Following comments will refer to these graphics. L is the left
5611 * extents which we are checking at the moment. 1-8 are the right
5612 * extents that we iterate.
5613 *
5614 * |-----L-----|
5615 * |-1-|-2a-|-3-|-4-|-5-|-6-|
5616 *
5617 * |-----L-----|
5618 * |--1--|-2b-|...(same as above)
5619 *
5620 * Alternative situation. Happens on files where extents got split.
5621 * |-----L-----|
5622 * |-----------7-----------|-6-|
5623 *
5624 * Alternative situation. Happens on files which got larger.
5625 * |-----L-----|
5626 * |-8-|
5627 * Nothing follows after 8.
5628 */
5629
5630 key.objectid = ekey->objectid;
5631 key.type = BTRFS_EXTENT_DATA_KEY;
5632 key.offset = ekey->offset;
5633 ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0);
5634 if (ret < 0)
5635 goto out;
5636 if (ret) {
5637 ret = 0;
5638 goto out;
5639 }
5640
5641 /*
5642 * Handle special case where the right side has no extents at all.
5643 */
5644 eb = path->nodes[0];
5645 slot = path->slots[0];
5646 btrfs_item_key_to_cpu(eb, &found_key, slot);
5647 if (found_key.objectid != key.objectid ||
5648 found_key.type != key.type) {
5649 /* If we're a hole then just pretend nothing changed */
5650 ret = (left_disknr) ? 0 : 1;
5651 goto out;
5652 }
5653
5654 /*
5655 * We're now on 2a, 2b or 7.
5656 */
5657 key = found_key;
5658 while (key.offset < ekey->offset + left_len) {
5659 ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
5660 right_type = btrfs_file_extent_type(eb, ei);
5661 if (right_type != BTRFS_FILE_EXTENT_REG &&
5662 right_type != BTRFS_FILE_EXTENT_INLINE) {
5663 ret = 0;
5664 goto out;
5665 }
5666
5667 if (right_type == BTRFS_FILE_EXTENT_INLINE) {
5668 right_len = btrfs_file_extent_ram_bytes(eb, ei);
5669 right_len = PAGE_ALIGN(right_len);
5670 } else {
5671 right_len = btrfs_file_extent_num_bytes(eb, ei);
5672 }
5673
5674 /*
5675 * Are we at extent 8? If yes, we know the extent is changed.
5676 * This may only happen on the first iteration.
5677 */
5678 if (found_key.offset + right_len <= ekey->offset) {
5679 /* If we're a hole just pretend nothing changed */
5680 ret = (left_disknr) ? 0 : 1;
5681 goto out;
5682 }
5683
5684 /*
5685 * We just wanted to see if when we have an inline extent, what
5686 * follows it is a regular extent (wanted to check the above
5687 * condition for inline extents too). This should normally not
5688 * happen but it's possible for example when we have an inline
5689 * compressed extent representing data with a size matching
5690 * the page size (currently the same as sector size).
5691 */
5692 if (right_type == BTRFS_FILE_EXTENT_INLINE) {
5693 ret = 0;
5694 goto out;
5695 }
5696
5697 right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
5698 right_offset = btrfs_file_extent_offset(eb, ei);
5699 right_gen = btrfs_file_extent_generation(eb, ei);
5700
5701 left_offset_fixed = left_offset;
5702 if (key.offset < ekey->offset) {
5703 /* Fix the right offset for 2a and 7. */
5704 right_offset += ekey->offset - key.offset;
5705 } else {
5706 /* Fix the left offset for all behind 2a and 2b */
5707 left_offset_fixed += key.offset - ekey->offset;
5708 }
5709
5710 /*
5711 * Check if we have the same extent.
5712 */
5713 if (left_disknr != right_disknr ||
5714 left_offset_fixed != right_offset ||
5715 left_gen != right_gen) {
5716 ret = 0;
5717 goto out;
5718 }
5719
5720 /*
5721 * Go to the next extent.
5722 */
5723 ret = btrfs_next_item(sctx->parent_root, path);
5724 if (ret < 0)
5725 goto out;
5726 if (!ret) {
5727 eb = path->nodes[0];
5728 slot = path->slots[0];
5729 btrfs_item_key_to_cpu(eb, &found_key, slot);
5730 }
5731 if (ret || found_key.objectid != key.objectid ||
5732 found_key.type != key.type) {
5733 key.offset += right_len;
5734 break;
5735 }
5736 if (found_key.offset != key.offset + right_len) {
5737 ret = 0;
5738 goto out;
5739 }
5740 key = found_key;
5741 }
5742
5743 /*
5744 * We're now behind the left extent (treat as unchanged) or at the end
5745 * of the right side (treat as changed).
5746 */
5747 if (key.offset >= ekey->offset + left_len)
5748 ret = 1;
5749 else
5750 ret = 0;
5751
5752
5753 out:
5754 btrfs_free_path(path);
5755 return ret;
5756 }
5757
5758 static int get_last_extent(struct send_ctx *sctx, u64 offset)
5759 {
5760 struct btrfs_path *path;
5761 struct btrfs_root *root = sctx->send_root;
5762 struct btrfs_key key;
5763 int ret;
5764
5765 path = alloc_path_for_send();
5766 if (!path)
5767 return -ENOMEM;
5768
5769 sctx->cur_inode_last_extent = 0;
5770
5771 key.objectid = sctx->cur_ino;
5772 key.type = BTRFS_EXTENT_DATA_KEY;
5773 key.offset = offset;
5774 ret = btrfs_search_slot_for_read(root, &key, path, 0, 1);
5775 if (ret < 0)
5776 goto out;
5777 ret = 0;
5778 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
5779 if (key.objectid != sctx->cur_ino || key.type != BTRFS_EXTENT_DATA_KEY)
5780 goto out;
5781
5782 sctx->cur_inode_last_extent = btrfs_file_extent_end(path);
5783 out:
5784 btrfs_free_path(path);
5785 return ret;
5786 }
5787
5788 static int range_is_hole_in_parent(struct send_ctx *sctx,
5789 const u64 start,
5790 const u64 end)
5791 {
5792 struct btrfs_path *path;
5793 struct btrfs_key key;
5794 struct btrfs_root *root = sctx->parent_root;
5795 u64 search_start = start;
5796 int ret;
5797
5798 path = alloc_path_for_send();
5799 if (!path)
5800 return -ENOMEM;
5801
5802 key.objectid = sctx->cur_ino;
5803 key.type = BTRFS_EXTENT_DATA_KEY;
5804 key.offset = search_start;
5805 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5806 if (ret < 0)
5807 goto out;
5808 if (ret > 0 && path->slots[0] > 0)
5809 path->slots[0]--;
5810
5811 while (search_start < end) {
5812 struct extent_buffer *leaf = path->nodes[0];
5813 int slot = path->slots[0];
5814 struct btrfs_file_extent_item *fi;
5815 u64 extent_end;
5816
5817 if (slot >= btrfs_header_nritems(leaf)) {
5818 ret = btrfs_next_leaf(root, path);
5819 if (ret < 0)
5820 goto out;
5821 else if (ret > 0)
5822 break;
5823 continue;
5824 }
5825
5826 btrfs_item_key_to_cpu(leaf, &key, slot);
5827 if (key.objectid < sctx->cur_ino ||
5828 key.type < BTRFS_EXTENT_DATA_KEY)
5829 goto next;
5830 if (key.objectid > sctx->cur_ino ||
5831 key.type > BTRFS_EXTENT_DATA_KEY ||
5832 key.offset >= end)
5833 break;
5834
5835 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5836 extent_end = btrfs_file_extent_end(path);
5837 if (extent_end <= start)
5838 goto next;
5839 if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) {
5840 search_start = extent_end;
5841 goto next;
5842 }
5843 ret = 0;
5844 goto out;
5845 next:
5846 path->slots[0]++;
5847 }
5848 ret = 1;
5849 out:
5850 btrfs_free_path(path);
5851 return ret;
5852 }
5853
5854 static int maybe_send_hole(struct send_ctx *sctx, struct btrfs_path *path,
5855 struct btrfs_key *key)
5856 {
5857 int ret = 0;
5858
5859 if (sctx->cur_ino != key->objectid || !need_send_hole(sctx))
5860 return 0;
5861
5862 if (sctx->cur_inode_last_extent == (u64)-1) {
5863 ret = get_last_extent(sctx, key->offset - 1);
5864 if (ret)
5865 return ret;
5866 }
5867
5868 if (path->slots[0] == 0 &&
5869 sctx->cur_inode_last_extent < key->offset) {
5870 /*
5871 * We might have skipped entire leafs that contained only
5872 * file extent items for our current inode. These leafs have
5873 * a generation number smaller (older) than the one in the
5874 * current leaf and the leaf our last extent came from, and
5875 * are located between these 2 leafs.
5876 */
5877 ret = get_last_extent(sctx, key->offset - 1);
5878 if (ret)
5879 return ret;
5880 }
5881
5882 if (sctx->cur_inode_last_extent < key->offset) {
5883 ret = range_is_hole_in_parent(sctx,
5884 sctx->cur_inode_last_extent,
5885 key->offset);
5886 if (ret < 0)
5887 return ret;
5888 else if (ret == 0)
5889 ret = send_hole(sctx, key->offset);
5890 else
5891 ret = 0;
5892 }
5893 sctx->cur_inode_last_extent = btrfs_file_extent_end(path);
5894 return ret;
5895 }
5896
5897 static int process_extent(struct send_ctx *sctx,
5898 struct btrfs_path *path,
5899 struct btrfs_key *key)
5900 {
5901 struct clone_root *found_clone = NULL;
5902 int ret = 0;
5903
5904 if (