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
  27/*
  28 * A fs_path is a helper to dynamically build path names with unknown size.
  29 * It reallocates the internal buffer on demand.
  30 * It allows fast adding of path elements on the right side (normal path) and
  31 * fast adding to the left side (reversed path). A reversed path can also be
  32 * unreversed if needed.
  33 */
  34struct fs_path {
  35	union {
  36		struct {
  37			char *start;
  38			char *end;
  39
  40			char *buf;
  41			unsigned short buf_len:15;
  42			unsigned short reversed:1;
  43			char inline_buf[];
  44		};
  45		/*
  46		 * Average path length does not exceed 200 bytes, we'll have
  47		 * better packing in the slab and higher chance to satisfy
  48		 * a allocation later during send.
  49		 */
  50		char pad[256];
  51	};
  52};
  53#define FS_PATH_INLINE_SIZE \
  54	(sizeof(struct fs_path) - offsetof(struct fs_path, inline_buf))
  55
  56
  57/* reused for each extent */
  58struct clone_root {
  59	struct btrfs_root *root;
  60	u64 ino;
  61	u64 offset;
  62
  63	u64 found_refs;
  64};
  65
  66#define SEND_CTX_MAX_NAME_CACHE_SIZE 128
  67#define SEND_CTX_NAME_CACHE_CLEAN_SIZE (SEND_CTX_MAX_NAME_CACHE_SIZE * 2)
  68
  69struct send_ctx {
  70	struct file *send_filp;
  71	loff_t send_off;
  72	char *send_buf;
  73	u32 send_size;
  74	u32 send_max_size;
  75	u64 total_send_size;
  76	u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];
  77	u64 flags;	/* 'flags' member of btrfs_ioctl_send_args is u64 */
  78
  79	struct btrfs_root *send_root;
  80	struct btrfs_root *parent_root;
  81	struct clone_root *clone_roots;
  82	int clone_roots_cnt;
  83
  84	/* current state of the compare_tree call */
  85	struct btrfs_path *left_path;
  86	struct btrfs_path *right_path;
  87	struct btrfs_key *cmp_key;
  88
  89	/*
  90	 * infos of the currently processed inode. In case of deleted inodes,
  91	 * these are the values from the deleted inode.
  92	 */
  93	u64 cur_ino;
  94	u64 cur_inode_gen;
  95	int cur_inode_new;
  96	int cur_inode_new_gen;
  97	int cur_inode_deleted;
  98	u64 cur_inode_size;
  99	u64 cur_inode_mode;
 100	u64 cur_inode_rdev;
 101	u64 cur_inode_last_extent;
 102	u64 cur_inode_next_write_offset;
 103
 104	u64 send_progress;
 105
 106	struct list_head new_refs;
 107	struct list_head deleted_refs;
 108
 109	struct radix_tree_root name_cache;
 110	struct list_head name_cache_list;
 111	int name_cache_size;
 112
 113	struct file_ra_state ra;
 114
 115	char *read_buf;
 116
 117	/*
 118	 * We process inodes by their increasing order, so if before an
 119	 * incremental send we reverse the parent/child relationship of
 120	 * directories such that a directory with a lower inode number was
 121	 * the parent of a directory with a higher inode number, and the one
 122	 * becoming the new parent got renamed too, we can't rename/move the
 123	 * directory with lower inode number when we finish processing it - we
 124	 * must process the directory with higher inode number first, then
 125	 * rename/move it and then rename/move the directory with lower inode
 126	 * number. Example follows.
 127	 *
 128	 * Tree state when the first send was performed:
 129	 *
 130	 * .
 131	 * |-- a                   (ino 257)
 132	 *     |-- b               (ino 258)
 133	 *         |
 134	 *         |
 135	 *         |-- c           (ino 259)
 136	 *         |   |-- d       (ino 260)
 137	 *         |
 138	 *         |-- c2          (ino 261)
 139	 *
 140	 * Tree state when the second (incremental) send is performed:
 141	 *
 142	 * .
 143	 * |-- a                   (ino 257)
 144	 *     |-- b               (ino 258)
 145	 *         |-- c2          (ino 261)
 146	 *             |-- d2      (ino 260)
 147	 *                 |-- cc  (ino 259)
 148	 *
 149	 * The sequence of steps that lead to the second state was:
 150	 *
 151	 * mv /a/b/c/d /a/b/c2/d2
 152	 * mv /a/b/c /a/b/c2/d2/cc
 153	 *
 154	 * "c" has lower inode number, but we can't move it (2nd mv operation)
 155	 * before we move "d", which has higher inode number.
 156	 *
 157	 * So we just memorize which move/rename operations must be performed
 158	 * later when their respective parent is processed and moved/renamed.
 159	 */
 160
 161	/* Indexed by parent directory inode number. */
 162	struct rb_root pending_dir_moves;
 163
 164	/*
 165	 * Reverse index, indexed by the inode number of a directory that
 166	 * is waiting for the move/rename of its immediate parent before its
 167	 * own move/rename can be performed.
 168	 */
 169	struct rb_root waiting_dir_moves;
 170
 171	/*
 172	 * A directory that is going to be rm'ed might have a child directory
 173	 * which is in the pending directory moves index above. In this case,
 174	 * the directory can only be removed after the move/rename of its child
 175	 * is performed. Example:
 176	 *
 177	 * Parent snapshot:
 178	 *
 179	 * .                        (ino 256)
 180	 * |-- a/                   (ino 257)
 181	 *     |-- b/               (ino 258)
 182	 *         |-- c/           (ino 259)
 183	 *         |   |-- x/       (ino 260)
 184	 *         |
 185	 *         |-- y/           (ino 261)
 186	 *
 187	 * Send snapshot:
 188	 *
 189	 * .                        (ino 256)
 190	 * |-- a/                   (ino 257)
 191	 *     |-- b/               (ino 258)
 192	 *         |-- YY/          (ino 261)
 193	 *              |-- x/      (ino 260)
 194	 *
 195	 * Sequence of steps that lead to the send snapshot:
 196	 * rm -f /a/b/c/foo.txt
 197	 * mv /a/b/y /a/b/YY
 198	 * mv /a/b/c/x /a/b/YY
 199	 * rmdir /a/b/c
 200	 *
 201	 * When the child is processed, its move/rename is delayed until its
 202	 * parent is processed (as explained above), but all other operations
 203	 * like update utimes, chown, chgrp, etc, are performed and the paths
 204	 * that it uses for those operations must use the orphanized name of
 205	 * its parent (the directory we're going to rm later), so we need to
 206	 * memorize that name.
 207	 *
 208	 * Indexed by the inode number of the directory to be deleted.
 209	 */
 210	struct rb_root orphan_dirs;
 211};
 212
 213struct pending_dir_move {
 214	struct rb_node node;
 215	struct list_head list;
 216	u64 parent_ino;
 217	u64 ino;
 218	u64 gen;
 219	struct list_head update_refs;
 220};
 221
 222struct waiting_dir_move {
 223	struct rb_node node;
 224	u64 ino;
 225	/*
 226	 * There might be some directory that could not be removed because it
 227	 * was waiting for this directory inode to be moved first. Therefore
 228	 * after this directory is moved, we can try to rmdir the ino rmdir_ino.
 229	 */
 230	u64 rmdir_ino;
 231	bool orphanized;
 232};
 233
 234struct orphan_dir_info {
 235	struct rb_node node;
 236	u64 ino;
 237	u64 gen;
 238};
 239
 240struct name_cache_entry {
 241	struct list_head list;
 242	/*
 243	 * radix_tree has only 32bit entries but we need to handle 64bit inums.
 244	 * We use the lower 32bit of the 64bit inum to store it in the tree. If
 245	 * more then one inum would fall into the same entry, we use radix_list
 246	 * to store the additional entries. radix_list is also used to store
 247	 * entries where two entries have the same inum but different
 248	 * generations.
 249	 */
 250	struct list_head radix_list;
 251	u64 ino;
 252	u64 gen;
 253	u64 parent_ino;
 254	u64 parent_gen;
 255	int ret;
 256	int need_later_update;
 257	int name_len;
 258	char name[];
 259};
 260
 261__cold
 262static void inconsistent_snapshot_error(struct send_ctx *sctx,
 263					enum btrfs_compare_tree_result result,
 264					const char *what)
 265{
 266	const char *result_string;
 267
 268	switch (result) {
 269	case BTRFS_COMPARE_TREE_NEW:
 270		result_string = "new";
 271		break;
 272	case BTRFS_COMPARE_TREE_DELETED:
 273		result_string = "deleted";
 274		break;
 275	case BTRFS_COMPARE_TREE_CHANGED:
 276		result_string = "updated";
 277		break;
 278	case BTRFS_COMPARE_TREE_SAME:
 279		ASSERT(0);
 280		result_string = "unchanged";
 281		break;
 282	default:
 283		ASSERT(0);
 284		result_string = "unexpected";
 285	}
 286
 287	btrfs_err(sctx->send_root->fs_info,
 288		  "Send: inconsistent snapshot, found %s %s for inode %llu without updated inode item, send root is %llu, parent root is %llu",
 289		  result_string, what, sctx->cmp_key->objectid,
 290		  sctx->send_root->root_key.objectid,
 291		  (sctx->parent_root ?
 292		   sctx->parent_root->root_key.objectid : 0));
 293}
 294
 295static int is_waiting_for_move(struct send_ctx *sctx, u64 ino);
 296
 297static struct waiting_dir_move *
 298get_waiting_dir_move(struct send_ctx *sctx, u64 ino);
 299
 300static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino);
 301
 302static int need_send_hole(struct send_ctx *sctx)
 303{
 304	return (sctx->parent_root && !sctx->cur_inode_new &&
 305		!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted &&
 306		S_ISREG(sctx->cur_inode_mode));
 307}
 308
 309static void fs_path_reset(struct fs_path *p)
 310{
 311	if (p->reversed) {
 312		p->start = p->buf + p->buf_len - 1;
 313		p->end = p->start;
 314		*p->start = 0;
 315	} else {
 316		p->start = p->buf;
 317		p->end = p->start;
 318		*p->start = 0;
 319	}
 320}
 321
 322static struct fs_path *fs_path_alloc(void)
 323{
 324	struct fs_path *p;
 325
 326	p = kmalloc(sizeof(*p), GFP_KERNEL);
 327	if (!p)
 328		return NULL;
 329	p->reversed = 0;
 330	p->buf = p->inline_buf;
 331	p->buf_len = FS_PATH_INLINE_SIZE;
 332	fs_path_reset(p);
 333	return p;
 334}
 335
 336static struct fs_path *fs_path_alloc_reversed(void)
 337{
 338	struct fs_path *p;
 339
 340	p = fs_path_alloc();
 341	if (!p)
 342		return NULL;
 343	p->reversed = 1;
 344	fs_path_reset(p);
 345	return p;
 346}
 347
 348static void fs_path_free(struct fs_path *p)
 349{
 350	if (!p)
 351		return;
 352	if (p->buf != p->inline_buf)
 353		kfree(p->buf);
 354	kfree(p);
 355}
 356
 357static int fs_path_len(struct fs_path *p)
 358{
 359	return p->end - p->start;
 360}
 361
 362static int fs_path_ensure_buf(struct fs_path *p, int len)
 363{
 364	char *tmp_buf;
 365	int path_len;
 366	int old_buf_len;
 367
 368	len++;
 369
 370	if (p->buf_len >= len)
 371		return 0;
 372
 373	if (len > PATH_MAX) {
 374		WARN_ON(1);
 375		return -ENOMEM;
 376	}
 377
 378	path_len = p->end - p->start;
 379	old_buf_len = p->buf_len;
 380
 381	/*
 382	 * First time the inline_buf does not suffice
 383	 */
 384	if (p->buf == p->inline_buf) {
 385		tmp_buf = kmalloc(len, GFP_KERNEL);
 386		if (tmp_buf)
 387			memcpy(tmp_buf, p->buf, old_buf_len);
 388	} else {
 389		tmp_buf = krealloc(p->buf, len, GFP_KERNEL);
 390	}
 391	if (!tmp_buf)
 392		return -ENOMEM;
 393	p->buf = tmp_buf;
 394	/*
 395	 * The real size of the buffer is bigger, this will let the fast path
 396	 * happen most of the time
 397	 */
 398	p->buf_len = ksize(p->buf);
 399
 400	if (p->reversed) {
 401		tmp_buf = p->buf + old_buf_len - path_len - 1;
 402		p->end = p->buf + p->buf_len - 1;
 403		p->start = p->end - path_len;
 404		memmove(p->start, tmp_buf, path_len + 1);
 405	} else {
 406		p->start = p->buf;
 407		p->end = p->start + path_len;
 408	}
 409	return 0;
 410}
 411
 412static int fs_path_prepare_for_add(struct fs_path *p, int name_len,
 413				   char **prepared)
 414{
 415	int ret;
 416	int new_len;
 417
 418	new_len = p->end - p->start + name_len;
 419	if (p->start != p->end)
 420		new_len++;
 421	ret = fs_path_ensure_buf(p, new_len);
 422	if (ret < 0)
 423		goto out;
 424
 425	if (p->reversed) {
 426		if (p->start != p->end)
 427			*--p->start = '/';
 428		p->start -= name_len;
 429		*prepared = p->start;
 430	} else {
 431		if (p->start != p->end)
 432			*p->end++ = '/';
 433		*prepared = p->end;
 434		p->end += name_len;
 435		*p->end = 0;
 436	}
 437
 438out:
 439	return ret;
 440}
 441
 442static int fs_path_add(struct fs_path *p, const char *name, int name_len)
 443{
 444	int ret;
 445	char *prepared;
 446
 447	ret = fs_path_prepare_for_add(p, name_len, &prepared);
 448	if (ret < 0)
 449		goto out;
 450	memcpy(prepared, name, name_len);
 451
 452out:
 453	return ret;
 454}
 455
 456static int fs_path_add_path(struct fs_path *p, struct fs_path *p2)
 457{
 458	int ret;
 459	char *prepared;
 460
 461	ret = fs_path_prepare_for_add(p, p2->end - p2->start, &prepared);
 462	if (ret < 0)
 463		goto out;
 464	memcpy(prepared, p2->start, p2->end - p2->start);
 465
 466out:
 467	return ret;
 468}
 469
 470static int fs_path_add_from_extent_buffer(struct fs_path *p,
 471					  struct extent_buffer *eb,
 472					  unsigned long off, int len)
 473{
 474	int ret;
 475	char *prepared;
 476
 477	ret = fs_path_prepare_for_add(p, len, &prepared);
 478	if (ret < 0)
 479		goto out;
 480
 481	read_extent_buffer(eb, prepared, off, len);
 482
 483out:
 484	return ret;
 485}
 486
 487static int fs_path_copy(struct fs_path *p, struct fs_path *from)
 488{
 489	int ret;
 490
 491	p->reversed = from->reversed;
 492	fs_path_reset(p);
 493
 494	ret = fs_path_add_path(p, from);
 495
 496	return ret;
 497}
 498
 499
 500static void fs_path_unreverse(struct fs_path *p)
 501{
 502	char *tmp;
 503	int len;
 504
 505	if (!p->reversed)
 506		return;
 507
 508	tmp = p->start;
 509	len = p->end - p->start;
 510	p->start = p->buf;
 511	p->end = p->start + len;
 512	memmove(p->start, tmp, len + 1);
 513	p->reversed = 0;
 514}
 515
 516static struct btrfs_path *alloc_path_for_send(void)
 517{
 518	struct btrfs_path *path;
 519
 520	path = btrfs_alloc_path();
 521	if (!path)
 522		return NULL;
 523	path->search_commit_root = 1;
 524	path->skip_locking = 1;
 525	path->need_commit_sem = 1;
 526	return path;
 527}
 528
 529static int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off)
 530{
 531	int ret;
 
 532	u32 pos = 0;
 533
 
 
 
 534	while (pos < len) {
 535		ret = kernel_write(filp, buf + pos, len - pos, off);
 536		/* TODO handle that correctly */
 537		/*if (ret == -ERESTARTSYS) {
 538			continue;
 539		}*/
 540		if (ret < 0)
 541			return ret;
 542		if (ret == 0) {
 543			return -EIO;
 
 544		}
 545		pos += ret;
 546	}
 547
 548	return 0;
 
 
 
 
 549}
 550
 551static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len)
 552{
 553	struct btrfs_tlv_header *hdr;
 554	int total_len = sizeof(*hdr) + len;
 555	int left = sctx->send_max_size - sctx->send_size;
 556
 557	if (unlikely(left < total_len))
 558		return -EOVERFLOW;
 559
 560	hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size);
 561	hdr->tlv_type = cpu_to_le16(attr);
 562	hdr->tlv_len = cpu_to_le16(len);
 563	memcpy(hdr + 1, data, len);
 564	sctx->send_size += total_len;
 565
 566	return 0;
 567}
 568
 569#define TLV_PUT_DEFINE_INT(bits) \
 570	static int tlv_put_u##bits(struct send_ctx *sctx,	 	\
 571			u##bits attr, u##bits value)			\
 572	{								\
 573		__le##bits __tmp = cpu_to_le##bits(value);		\
 574		return tlv_put(sctx, attr, &__tmp, sizeof(__tmp));	\
 575	}
 576
 577TLV_PUT_DEFINE_INT(64)
 578
 579static int tlv_put_string(struct send_ctx *sctx, u16 attr,
 580			  const char *str, int len)
 581{
 582	if (len == -1)
 583		len = strlen(str);
 584	return tlv_put(sctx, attr, str, len);
 585}
 586
 587static int tlv_put_uuid(struct send_ctx *sctx, u16 attr,
 588			const u8 *uuid)
 589{
 590	return tlv_put(sctx, attr, uuid, BTRFS_UUID_SIZE);
 591}
 592
 593static int tlv_put_btrfs_timespec(struct send_ctx *sctx, u16 attr,
 594				  struct extent_buffer *eb,
 595				  struct btrfs_timespec *ts)
 596{
 597	struct btrfs_timespec bts;
 598	read_extent_buffer(eb, &bts, (unsigned long)ts, sizeof(bts));
 599	return tlv_put(sctx, attr, &bts, sizeof(bts));
 600}
 601
 602
 603#define TLV_PUT(sctx, attrtype, data, attrlen) \
 604	do { \
 605		ret = tlv_put(sctx, attrtype, data, attrlen); \
 606		if (ret < 0) \
 607			goto tlv_put_failure; \
 608	} while (0)
 609
 610#define TLV_PUT_INT(sctx, attrtype, bits, value) \
 611	do { \
 612		ret = tlv_put_u##bits(sctx, attrtype, value); \
 613		if (ret < 0) \
 614			goto tlv_put_failure; \
 615	} while (0)
 616
 617#define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data)
 618#define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data)
 619#define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data)
 620#define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data)
 621#define TLV_PUT_STRING(sctx, attrtype, str, len) \
 622	do { \
 623		ret = tlv_put_string(sctx, attrtype, str, len); \
 624		if (ret < 0) \
 625			goto tlv_put_failure; \
 626	} while (0)
 627#define TLV_PUT_PATH(sctx, attrtype, p) \
 628	do { \
 629		ret = tlv_put_string(sctx, attrtype, p->start, \
 630			p->end - p->start); \
 631		if (ret < 0) \
 632			goto tlv_put_failure; \
 633	} while(0)
 634#define TLV_PUT_UUID(sctx, attrtype, uuid) \
 635	do { \
 636		ret = tlv_put_uuid(sctx, attrtype, uuid); \
 637		if (ret < 0) \
 638			goto tlv_put_failure; \
 639	} while (0)
 640#define TLV_PUT_BTRFS_TIMESPEC(sctx, attrtype, eb, ts) \
 641	do { \
 642		ret = tlv_put_btrfs_timespec(sctx, attrtype, eb, ts); \
 643		if (ret < 0) \
 644			goto tlv_put_failure; \
 645	} while (0)
 646
 647static int send_header(struct send_ctx *sctx)
 648{
 649	struct btrfs_stream_header hdr;
 650
 651	strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
 652	hdr.version = cpu_to_le32(BTRFS_SEND_STREAM_VERSION);
 653
 654	return write_buf(sctx->send_filp, &hdr, sizeof(hdr),
 655					&sctx->send_off);
 656}
 657
 658/*
 659 * For each command/item we want to send to userspace, we call this function.
 660 */
 661static int begin_cmd(struct send_ctx *sctx, int cmd)
 662{
 663	struct btrfs_cmd_header *hdr;
 664
 665	if (WARN_ON(!sctx->send_buf))
 666		return -EINVAL;
 667
 668	BUG_ON(sctx->send_size);
 669
 670	sctx->send_size += sizeof(*hdr);
 671	hdr = (struct btrfs_cmd_header *)sctx->send_buf;
 672	hdr->cmd = cpu_to_le16(cmd);
 673
 674	return 0;
 675}
 676
 677static int send_cmd(struct send_ctx *sctx)
 678{
 679	int ret;
 680	struct btrfs_cmd_header *hdr;
 681	u32 crc;
 682
 683	hdr = (struct btrfs_cmd_header *)sctx->send_buf;
 684	hdr->len = cpu_to_le32(sctx->send_size - sizeof(*hdr));
 685	hdr->crc = 0;
 686
 687	crc = crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
 688	hdr->crc = cpu_to_le32(crc);
 689
 690	ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size,
 691					&sctx->send_off);
 692
 693	sctx->total_send_size += sctx->send_size;
 694	sctx->cmd_send_size[le16_to_cpu(hdr->cmd)] += sctx->send_size;
 695	sctx->send_size = 0;
 696
 697	return ret;
 698}
 699
 700/*
 701 * Sends a move instruction to user space
 702 */
 703static int send_rename(struct send_ctx *sctx,
 704		     struct fs_path *from, struct fs_path *to)
 705{
 706	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
 707	int ret;
 708
 709	btrfs_debug(fs_info, "send_rename %s -> %s", from->start, to->start);
 710
 711	ret = begin_cmd(sctx, BTRFS_SEND_C_RENAME);
 712	if (ret < 0)
 713		goto out;
 714
 715	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, from);
 716	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_TO, to);
 717
 718	ret = send_cmd(sctx);
 719
 720tlv_put_failure:
 721out:
 722	return ret;
 723}
 724
 725/*
 726 * Sends a link instruction to user space
 727 */
 728static int send_link(struct send_ctx *sctx,
 729		     struct fs_path *path, struct fs_path *lnk)
 730{
 731	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
 732	int ret;
 733
 734	btrfs_debug(fs_info, "send_link %s -> %s", path->start, lnk->start);
 735
 736	ret = begin_cmd(sctx, BTRFS_SEND_C_LINK);
 737	if (ret < 0)
 738		goto out;
 739
 740	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
 741	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, lnk);
 742
 743	ret = send_cmd(sctx);
 744
 745tlv_put_failure:
 746out:
 747	return ret;
 748}
 749
 750/*
 751 * Sends an unlink instruction to user space
 752 */
 753static int send_unlink(struct send_ctx *sctx, struct fs_path *path)
 754{
 755	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
 756	int ret;
 757
 758	btrfs_debug(fs_info, "send_unlink %s", path->start);
 759
 760	ret = begin_cmd(sctx, BTRFS_SEND_C_UNLINK);
 761	if (ret < 0)
 762		goto out;
 763
 764	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
 765
 766	ret = send_cmd(sctx);
 767
 768tlv_put_failure:
 769out:
 770	return ret;
 771}
 772
 773/*
 774 * Sends a rmdir instruction to user space
 775 */
 776static int send_rmdir(struct send_ctx *sctx, struct fs_path *path)
 777{
 778	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
 779	int ret;
 780
 781	btrfs_debug(fs_info, "send_rmdir %s", path->start);
 782
 783	ret = begin_cmd(sctx, BTRFS_SEND_C_RMDIR);
 784	if (ret < 0)
 785		goto out;
 786
 787	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
 788
 789	ret = send_cmd(sctx);
 790
 791tlv_put_failure:
 792out:
 793	return ret;
 794}
 795
 796/*
 797 * Helper function to retrieve some fields from an inode item.
 798 */
 799static int __get_inode_info(struct btrfs_root *root, struct btrfs_path *path,
 800			  u64 ino, u64 *size, u64 *gen, u64 *mode, u64 *uid,
 801			  u64 *gid, u64 *rdev)
 802{
 803	int ret;
 804	struct btrfs_inode_item *ii;
 805	struct btrfs_key key;
 806
 807	key.objectid = ino;
 808	key.type = BTRFS_INODE_ITEM_KEY;
 809	key.offset = 0;
 810	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 811	if (ret) {
 812		if (ret > 0)
 813			ret = -ENOENT;
 814		return ret;
 815	}
 816
 817	ii = btrfs_item_ptr(path->nodes[0], path->slots[0],
 818			struct btrfs_inode_item);
 819	if (size)
 820		*size = btrfs_inode_size(path->nodes[0], ii);
 821	if (gen)
 822		*gen = btrfs_inode_generation(path->nodes[0], ii);
 823	if (mode)
 824		*mode = btrfs_inode_mode(path->nodes[0], ii);
 825	if (uid)
 826		*uid = btrfs_inode_uid(path->nodes[0], ii);
 827	if (gid)
 828		*gid = btrfs_inode_gid(path->nodes[0], ii);
 829	if (rdev)
 830		*rdev = btrfs_inode_rdev(path->nodes[0], ii);
 831
 832	return ret;
 833}
 834
 835static int get_inode_info(struct btrfs_root *root,
 836			  u64 ino, u64 *size, u64 *gen,
 837			  u64 *mode, u64 *uid, u64 *gid,
 838			  u64 *rdev)
 839{
 840	struct btrfs_path *path;
 841	int ret;
 842
 843	path = alloc_path_for_send();
 844	if (!path)
 845		return -ENOMEM;
 846	ret = __get_inode_info(root, path, ino, size, gen, mode, uid, gid,
 847			       rdev);
 848	btrfs_free_path(path);
 849	return ret;
 850}
 851
 852typedef int (*iterate_inode_ref_t)(int num, u64 dir, int index,
 853				   struct fs_path *p,
 854				   void *ctx);
 855
 856/*
 857 * Helper function to iterate the entries in ONE btrfs_inode_ref or
 858 * btrfs_inode_extref.
 859 * The iterate callback may return a non zero value to stop iteration. This can
 860 * be a negative value for error codes or 1 to simply stop it.
 861 *
 862 * path must point to the INODE_REF or INODE_EXTREF when called.
 863 */
 864static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path,
 865			     struct btrfs_key *found_key, int resolve,
 866			     iterate_inode_ref_t iterate, void *ctx)
 867{
 868	struct extent_buffer *eb = path->nodes[0];
 869	struct btrfs_item *item;
 870	struct btrfs_inode_ref *iref;
 871	struct btrfs_inode_extref *extref;
 872	struct btrfs_path *tmp_path;
 873	struct fs_path *p;
 874	u32 cur = 0;
 875	u32 total;
 876	int slot = path->slots[0];
 877	u32 name_len;
 878	char *start;
 879	int ret = 0;
 880	int num = 0;
 881	int index;
 882	u64 dir;
 883	unsigned long name_off;
 884	unsigned long elem_size;
 885	unsigned long ptr;
 886
 887	p = fs_path_alloc_reversed();
 888	if (!p)
 889		return -ENOMEM;
 890
 891	tmp_path = alloc_path_for_send();
 892	if (!tmp_path) {
 893		fs_path_free(p);
 894		return -ENOMEM;
 895	}
 896
 897
 898	if (found_key->type == BTRFS_INODE_REF_KEY) {
 899		ptr = (unsigned long)btrfs_item_ptr(eb, slot,
 900						    struct btrfs_inode_ref);
 901		item = btrfs_item_nr(slot);
 902		total = btrfs_item_size(eb, item);
 903		elem_size = sizeof(*iref);
 904	} else {
 905		ptr = btrfs_item_ptr_offset(eb, slot);
 906		total = btrfs_item_size_nr(eb, slot);
 907		elem_size = sizeof(*extref);
 908	}
 909
 910	while (cur < total) {
 911		fs_path_reset(p);
 912
 913		if (found_key->type == BTRFS_INODE_REF_KEY) {
 914			iref = (struct btrfs_inode_ref *)(ptr + cur);
 915			name_len = btrfs_inode_ref_name_len(eb, iref);
 916			name_off = (unsigned long)(iref + 1);
 917			index = btrfs_inode_ref_index(eb, iref);
 918			dir = found_key->offset;
 919		} else {
 920			extref = (struct btrfs_inode_extref *)(ptr + cur);
 921			name_len = btrfs_inode_extref_name_len(eb, extref);
 922			name_off = (unsigned long)&extref->name;
 923			index = btrfs_inode_extref_index(eb, extref);
 924			dir = btrfs_inode_extref_parent(eb, extref);
 925		}
 926
 927		if (resolve) {
 928			start = btrfs_ref_to_path(root, tmp_path, name_len,
 929						  name_off, eb, dir,
 930						  p->buf, p->buf_len);
 931			if (IS_ERR(start)) {
 932				ret = PTR_ERR(start);
 933				goto out;
 934			}
 935			if (start < p->buf) {
 936				/* overflow , try again with larger buffer */
 937				ret = fs_path_ensure_buf(p,
 938						p->buf_len + p->buf - start);
 939				if (ret < 0)
 940					goto out;
 941				start = btrfs_ref_to_path(root, tmp_path,
 942							  name_len, name_off,
 943							  eb, dir,
 944							  p->buf, p->buf_len);
 945				if (IS_ERR(start)) {
 946					ret = PTR_ERR(start);
 947					goto out;
 948				}
 949				BUG_ON(start < p->buf);
 950			}
 951			p->start = start;
 952		} else {
 953			ret = fs_path_add_from_extent_buffer(p, eb, name_off,
 954							     name_len);
 955			if (ret < 0)
 956				goto out;
 957		}
 958
 959		cur += elem_size + name_len;
 960		ret = iterate(num, dir, index, p, ctx);
 961		if (ret)
 962			goto out;
 963		num++;
 964	}
 965
 966out:
 967	btrfs_free_path(tmp_path);
 968	fs_path_free(p);
 969	return ret;
 970}
 971
 972typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key,
 973				  const char *name, int name_len,
 974				  const char *data, int data_len,
 975				  u8 type, void *ctx);
 976
 977/*
 978 * Helper function to iterate the entries in ONE btrfs_dir_item.
 979 * The iterate callback may return a non zero value to stop iteration. This can
 980 * be a negative value for error codes or 1 to simply stop it.
 981 *
 982 * path must point to the dir item when called.
 983 */
 984static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path,
 
 985			    iterate_dir_item_t iterate, void *ctx)
 986{
 987	int ret = 0;
 988	struct extent_buffer *eb;
 989	struct btrfs_item *item;
 990	struct btrfs_dir_item *di;
 991	struct btrfs_key di_key;
 992	char *buf = NULL;
 993	int buf_len;
 994	u32 name_len;
 995	u32 data_len;
 996	u32 cur;
 997	u32 len;
 998	u32 total;
 999	int slot;
1000	int num;
1001	u8 type;
1002
1003	/*
1004	 * Start with a small buffer (1 page). If later we end up needing more
1005	 * space, which can happen for xattrs on a fs with a leaf size greater
1006	 * then the page size, attempt to increase the buffer. Typically xattr
1007	 * values are small.
1008	 */
1009	buf_len = PATH_MAX;
1010	buf = kmalloc(buf_len, GFP_KERNEL);
1011	if (!buf) {
1012		ret = -ENOMEM;
1013		goto out;
1014	}
1015
1016	eb = path->nodes[0];
1017	slot = path->slots[0];
1018	item = btrfs_item_nr(slot);
1019	di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
1020	cur = 0;
1021	len = 0;
1022	total = btrfs_item_size(eb, item);
1023
1024	num = 0;
1025	while (cur < total) {
1026		name_len = btrfs_dir_name_len(eb, di);
1027		data_len = btrfs_dir_data_len(eb, di);
1028		type = btrfs_dir_type(eb, di);
1029		btrfs_dir_item_key_to_cpu(eb, di, &di_key);
1030
1031		if (type == BTRFS_FT_XATTR) {
1032			if (name_len > XATTR_NAME_MAX) {
1033				ret = -ENAMETOOLONG;
1034				goto out;
1035			}
1036			if (name_len + data_len >
1037					BTRFS_MAX_XATTR_SIZE(root->fs_info)) {
1038				ret = -E2BIG;
1039				goto out;
1040			}
1041		} else {
1042			/*
1043			 * Path too long
1044			 */
1045			if (name_len + data_len > PATH_MAX) {
1046				ret = -ENAMETOOLONG;
1047				goto out;
1048			}
1049		}
1050
1051		if (name_len + data_len > buf_len) {
1052			buf_len = name_len + data_len;
1053			if (is_vmalloc_addr(buf)) {
1054				vfree(buf);
1055				buf = NULL;
1056			} else {
1057				char *tmp = krealloc(buf, buf_len,
1058						GFP_KERNEL | __GFP_NOWARN);
1059
1060				if (!tmp)
1061					kfree(buf);
1062				buf = tmp;
1063			}
1064			if (!buf) {
1065				buf = kvmalloc(buf_len, GFP_KERNEL);
1066				if (!buf) {
1067					ret = -ENOMEM;
1068					goto out;
1069				}
1070			}
1071		}
1072
1073		read_extent_buffer(eb, buf, (unsigned long)(di + 1),
1074				name_len + data_len);
1075
1076		len = sizeof(*di) + name_len + data_len;
1077		di = (struct btrfs_dir_item *)((char *)di + len);
1078		cur += len;
1079
1080		ret = iterate(num, &di_key, buf, name_len, buf + name_len,
1081				data_len, type, ctx);
1082		if (ret < 0)
1083			goto out;
1084		if (ret) {
1085			ret = 0;
1086			goto out;
1087		}
1088
1089		num++;
1090	}
1091
1092out:
1093	kvfree(buf);
1094	return ret;
1095}
1096
1097static int __copy_first_ref(int num, u64 dir, int index,
1098			    struct fs_path *p, void *ctx)
1099{
1100	int ret;
1101	struct fs_path *pt = ctx;
1102
1103	ret = fs_path_copy(pt, p);
1104	if (ret < 0)
1105		return ret;
1106
1107	/* we want the first only */
1108	return 1;
1109}
1110
1111/*
1112 * Retrieve the first path of an inode. If an inode has more then one
1113 * ref/hardlink, this is ignored.
1114 */
1115static int get_inode_path(struct btrfs_root *root,
1116			  u64 ino, struct fs_path *path)
1117{
1118	int ret;
1119	struct btrfs_key key, found_key;
1120	struct btrfs_path *p;
1121
1122	p = alloc_path_for_send();
1123	if (!p)
1124		return -ENOMEM;
1125
1126	fs_path_reset(path);
1127
1128	key.objectid = ino;
1129	key.type = BTRFS_INODE_REF_KEY;
1130	key.offset = 0;
1131
1132	ret = btrfs_search_slot_for_read(root, &key, p, 1, 0);
1133	if (ret < 0)
1134		goto out;
1135	if (ret) {
1136		ret = 1;
1137		goto out;
1138	}
1139	btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]);
1140	if (found_key.objectid != ino ||
1141	    (found_key.type != BTRFS_INODE_REF_KEY &&
1142	     found_key.type != BTRFS_INODE_EXTREF_KEY)) {
1143		ret = -ENOENT;
1144		goto out;
1145	}
1146
1147	ret = iterate_inode_ref(root, p, &found_key, 1,
1148				__copy_first_ref, path);
1149	if (ret < 0)
1150		goto out;
1151	ret = 0;
1152
1153out:
1154	btrfs_free_path(p);
1155	return ret;
1156}
1157
1158struct backref_ctx {
1159	struct send_ctx *sctx;
1160
1161	struct btrfs_path *path;
1162	/* number of total found references */
1163	u64 found;
1164
1165	/*
1166	 * used for clones found in send_root. clones found behind cur_objectid
1167	 * and cur_offset are not considered as allowed clones.
1168	 */
1169	u64 cur_objectid;
1170	u64 cur_offset;
1171
1172	/* may be truncated in case it's the last extent in a file */
1173	u64 extent_len;
1174
1175	/* data offset in the file extent item */
1176	u64 data_offset;
1177
1178	/* Just to check for bugs in backref resolving */
1179	int found_itself;
1180};
1181
1182static int __clone_root_cmp_bsearch(const void *key, const void *elt)
1183{
1184	u64 root = (u64)(uintptr_t)key;
1185	struct clone_root *cr = (struct clone_root *)elt;
1186
1187	if (root < cr->root->objectid)
1188		return -1;
1189	if (root > cr->root->objectid)
1190		return 1;
1191	return 0;
1192}
1193
1194static int __clone_root_cmp_sort(const void *e1, const void *e2)
1195{
1196	struct clone_root *cr1 = (struct clone_root *)e1;
1197	struct clone_root *cr2 = (struct clone_root *)e2;
1198
1199	if (cr1->root->objectid < cr2->root->objectid)
1200		return -1;
1201	if (cr1->root->objectid > cr2->root->objectid)
1202		return 1;
1203	return 0;
1204}
1205
1206/*
1207 * Called for every backref that is found for the current extent.
1208 * Results are collected in sctx->clone_roots->ino/offset/found_refs
1209 */
1210static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_)
1211{
1212	struct backref_ctx *bctx = ctx_;
1213	struct clone_root *found;
1214	int ret;
1215	u64 i_size;
1216
1217	/* First check if the root is in the list of accepted clone sources */
1218	found = bsearch((void *)(uintptr_t)root, bctx->sctx->clone_roots,
1219			bctx->sctx->clone_roots_cnt,
1220			sizeof(struct clone_root),
1221			__clone_root_cmp_bsearch);
1222	if (!found)
1223		return 0;
1224
1225	if (found->root == bctx->sctx->send_root &&
1226	    ino == bctx->cur_objectid &&
1227	    offset == bctx->cur_offset) {
1228		bctx->found_itself = 1;
1229	}
1230
1231	/*
1232	 * There are inodes that have extents that lie behind its i_size. Don't
1233	 * accept clones from these extents.
1234	 */
1235	ret = __get_inode_info(found->root, bctx->path, ino, &i_size, NULL, NULL,
1236			       NULL, NULL, NULL);
1237	btrfs_release_path(bctx->path);
1238	if (ret < 0)
1239		return ret;
1240
1241	if (offset + bctx->data_offset + bctx->extent_len > i_size)
1242		return 0;
1243
1244	/*
1245	 * Make sure we don't consider clones from send_root that are
1246	 * behind the current inode/offset.
1247	 */
1248	if (found->root == bctx->sctx->send_root) {
1249		/*
1250		 * TODO for the moment we don't accept clones from the inode
1251		 * that is currently send. We may change this when
1252		 * BTRFS_IOC_CLONE_RANGE supports cloning from and to the same
1253		 * file.
1254		 */
1255		if (ino >= bctx->cur_objectid)
1256			return 0;
 
 
 
 
 
 
1257	}
1258
1259	bctx->found++;
1260	found->found_refs++;
1261	if (ino < found->ino) {
1262		found->ino = ino;
1263		found->offset = offset;
1264	} else if (found->ino == ino) {
1265		/*
1266		 * same extent found more then once in the same file.
1267		 */
1268		if (found->offset > offset + bctx->extent_len)
1269			found->offset = offset;
1270	}
1271
1272	return 0;
1273}
1274
1275/*
1276 * Given an inode, offset and extent item, it finds a good clone for a clone
1277 * instruction. Returns -ENOENT when none could be found. The function makes
1278 * sure that the returned clone is usable at the point where sending is at the
1279 * moment. This means, that no clones are accepted which lie behind the current
1280 * inode+offset.
1281 *
1282 * path must point to the extent item when called.
1283 */
1284static int find_extent_clone(struct send_ctx *sctx,
1285			     struct btrfs_path *path,
1286			     u64 ino, u64 data_offset,
1287			     u64 ino_size,
1288			     struct clone_root **found)
1289{
1290	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
1291	int ret;
1292	int extent_type;
1293	u64 logical;
1294	u64 disk_byte;
1295	u64 num_bytes;
1296	u64 extent_item_pos;
1297	u64 flags = 0;
1298	struct btrfs_file_extent_item *fi;
1299	struct extent_buffer *eb = path->nodes[0];
1300	struct backref_ctx *backref_ctx = NULL;
1301	struct clone_root *cur_clone_root;
1302	struct btrfs_key found_key;
1303	struct btrfs_path *tmp_path;
1304	int compressed;
1305	u32 i;
1306
1307	tmp_path = alloc_path_for_send();
1308	if (!tmp_path)
1309		return -ENOMEM;
1310
1311	/* We only use this path under the commit sem */
1312	tmp_path->need_commit_sem = 0;
1313
1314	backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_KERNEL);
1315	if (!backref_ctx) {
1316		ret = -ENOMEM;
1317		goto out;
1318	}
1319
1320	backref_ctx->path = tmp_path;
1321
1322	if (data_offset >= ino_size) {
1323		/*
1324		 * There may be extents that lie behind the file's size.
1325		 * I at least had this in combination with snapshotting while
1326		 * writing large files.
1327		 */
1328		ret = 0;
1329		goto out;
1330	}
1331
1332	fi = btrfs_item_ptr(eb, path->slots[0],
1333			struct btrfs_file_extent_item);
1334	extent_type = btrfs_file_extent_type(eb, fi);
1335	if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1336		ret = -ENOENT;
1337		goto out;
1338	}
1339	compressed = btrfs_file_extent_compression(eb, fi);
1340
1341	num_bytes = btrfs_file_extent_num_bytes(eb, fi);
1342	disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
1343	if (disk_byte == 0) {
1344		ret = -ENOENT;
1345		goto out;
1346	}
1347	logical = disk_byte + btrfs_file_extent_offset(eb, fi);
1348
1349	down_read(&fs_info->commit_root_sem);
1350	ret = extent_from_logical(fs_info, disk_byte, tmp_path,
1351				  &found_key, &flags);
1352	up_read(&fs_info->commit_root_sem);
1353	btrfs_release_path(tmp_path);
1354
1355	if (ret < 0)
1356		goto out;
1357	if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1358		ret = -EIO;
1359		goto out;
1360	}
1361
1362	/*
1363	 * Setup the clone roots.
1364	 */
1365	for (i = 0; i < sctx->clone_roots_cnt; i++) {
1366		cur_clone_root = sctx->clone_roots + i;
1367		cur_clone_root->ino = (u64)-1;
1368		cur_clone_root->offset = 0;
1369		cur_clone_root->found_refs = 0;
1370	}
1371
1372	backref_ctx->sctx = sctx;
1373	backref_ctx->found = 0;
1374	backref_ctx->cur_objectid = ino;
1375	backref_ctx->cur_offset = data_offset;
1376	backref_ctx->found_itself = 0;
1377	backref_ctx->extent_len = num_bytes;
1378	/*
1379	 * For non-compressed extents iterate_extent_inodes() gives us extent
1380	 * offsets that already take into account the data offset, but not for
1381	 * compressed extents, since the offset is logical and not relative to
1382	 * the physical extent locations. We must take this into account to
1383	 * avoid sending clone offsets that go beyond the source file's size,
1384	 * which would result in the clone ioctl failing with -EINVAL on the
1385	 * receiving end.
1386	 */
1387	if (compressed == BTRFS_COMPRESS_NONE)
1388		backref_ctx->data_offset = 0;
1389	else
1390		backref_ctx->data_offset = btrfs_file_extent_offset(eb, fi);
1391
1392	/*
1393	 * The last extent of a file may be too large due to page alignment.
1394	 * We need to adjust extent_len in this case so that the checks in
1395	 * __iterate_backrefs work.
1396	 */
1397	if (data_offset + num_bytes >= ino_size)
1398		backref_ctx->extent_len = ino_size - data_offset;
1399
1400	/*
1401	 * Now collect all backrefs.
1402	 */
1403	if (compressed == BTRFS_COMPRESS_NONE)
1404		extent_item_pos = logical - found_key.objectid;
1405	else
1406		extent_item_pos = 0;
1407	ret = iterate_extent_inodes(fs_info, found_key.objectid,
1408				    extent_item_pos, 1, __iterate_backrefs,
1409				    backref_ctx, false);
1410
1411	if (ret < 0)
1412		goto out;
1413
1414	if (!backref_ctx->found_itself) {
1415		/* found a bug in backref code? */
1416		ret = -EIO;
1417		btrfs_err(fs_info,
1418			  "did not find backref in send_root. inode=%llu, offset=%llu, disk_byte=%llu found extent=%llu",
1419			  ino, data_offset, disk_byte, found_key.objectid);
 
1420		goto out;
1421	}
1422
1423	btrfs_debug(fs_info,
1424		    "find_extent_clone: data_offset=%llu, ino=%llu, num_bytes=%llu, logical=%llu",
1425		    data_offset, ino, num_bytes, logical);
 
1426
1427	if (!backref_ctx->found)
1428		btrfs_debug(fs_info, "no clones found");
1429
1430	cur_clone_root = NULL;
1431	for (i = 0; i < sctx->clone_roots_cnt; i++) {
1432		if (sctx->clone_roots[i].found_refs) {
1433			if (!cur_clone_root)
1434				cur_clone_root = sctx->clone_roots + i;
1435			else if (sctx->clone_roots[i].root == sctx->send_root)
1436				/* prefer clones from send_root over others */
1437				cur_clone_root = sctx->clone_roots + i;
1438		}
1439
1440	}
1441
1442	if (cur_clone_root) {
 
 
 
 
 
 
 
 
 
 
1443		*found = cur_clone_root;
1444		ret = 0;
1445	} else {
1446		ret = -ENOENT;
1447	}
1448
1449out:
1450	btrfs_free_path(tmp_path);
1451	kfree(backref_ctx);
1452	return ret;
1453}
1454
1455static int read_symlink(struct btrfs_root *root,
1456			u64 ino,
1457			struct fs_path *dest)
1458{
1459	int ret;
1460	struct btrfs_path *path;
1461	struct btrfs_key key;
1462	struct btrfs_file_extent_item *ei;
1463	u8 type;
1464	u8 compression;
1465	unsigned long off;
1466	int len;
1467
1468	path = alloc_path_for_send();
1469	if (!path)
1470		return -ENOMEM;
1471
1472	key.objectid = ino;
1473	key.type = BTRFS_EXTENT_DATA_KEY;
1474	key.offset = 0;
1475	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1476	if (ret < 0)
1477		goto out;
1478	if (ret) {
1479		/*
1480		 * An empty symlink inode. Can happen in rare error paths when
1481		 * creating a symlink (transaction committed before the inode
1482		 * eviction handler removed the symlink inode items and a crash
1483		 * happened in between or the subvol was snapshoted in between).
1484		 * Print an informative message to dmesg/syslog so that the user
1485		 * can delete the symlink.
1486		 */
1487		btrfs_err(root->fs_info,
1488			  "Found empty symlink inode %llu at root %llu",
1489			  ino, root->root_key.objectid);
1490		ret = -EIO;
1491		goto out;
1492	}
1493
1494	ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
1495			struct btrfs_file_extent_item);
1496	type = btrfs_file_extent_type(path->nodes[0], ei);
1497	compression = btrfs_file_extent_compression(path->nodes[0], ei);
1498	BUG_ON(type != BTRFS_FILE_EXTENT_INLINE);
1499	BUG_ON(compression);
1500
1501	off = btrfs_file_extent_inline_start(ei);
1502	len = btrfs_file_extent_inline_len(path->nodes[0], path->slots[0], ei);
1503
1504	ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len);
1505
1506out:
1507	btrfs_free_path(path);
1508	return ret;
1509}
1510
1511/*
1512 * Helper function to generate a file name that is unique in the root of
1513 * send_root and parent_root. This is used to generate names for orphan inodes.
1514 */
1515static int gen_unique_name(struct send_ctx *sctx,
1516			   u64 ino, u64 gen,
1517			   struct fs_path *dest)
1518{
1519	int ret = 0;
1520	struct btrfs_path *path;
1521	struct btrfs_dir_item *di;
1522	char tmp[64];
1523	int len;
1524	u64 idx = 0;
1525
1526	path = alloc_path_for_send();
1527	if (!path)
1528		return -ENOMEM;
1529
1530	while (1) {
1531		len = snprintf(tmp, sizeof(tmp), "o%llu-%llu-%llu",
1532				ino, gen, idx);
1533		ASSERT(len < sizeof(tmp));
1534
1535		di = btrfs_lookup_dir_item(NULL, sctx->send_root,
1536				path, BTRFS_FIRST_FREE_OBJECTID,
1537				tmp, strlen(tmp), 0);
1538		btrfs_release_path(path);
1539		if (IS_ERR(di)) {
1540			ret = PTR_ERR(di);
1541			goto out;
1542		}
1543		if (di) {
1544			/* not unique, try again */
1545			idx++;
1546			continue;
1547		}
1548
1549		if (!sctx->parent_root) {
1550			/* unique */
1551			ret = 0;
1552			break;
1553		}
1554
1555		di = btrfs_lookup_dir_item(NULL, sctx->parent_root,
1556				path, BTRFS_FIRST_FREE_OBJECTID,
1557				tmp, strlen(tmp), 0);
1558		btrfs_release_path(path);
1559		if (IS_ERR(di)) {
1560			ret = PTR_ERR(di);
1561			goto out;
1562		}
1563		if (di) {
1564			/* not unique, try again */
1565			idx++;
1566			continue;
1567		}
1568		/* unique */
1569		break;
1570	}
1571
1572	ret = fs_path_add(dest, tmp, strlen(tmp));
1573
1574out:
1575	btrfs_free_path(path);
1576	return ret;
1577}
1578
1579enum inode_state {
1580	inode_state_no_change,
1581	inode_state_will_create,
1582	inode_state_did_create,
1583	inode_state_will_delete,
1584	inode_state_did_delete,
1585};
1586
1587static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen)
1588{
1589	int ret;
1590	int left_ret;
1591	int right_ret;
1592	u64 left_gen;
1593	u64 right_gen;
1594
1595	ret = get_inode_info(sctx->send_root, ino, NULL, &left_gen, NULL, NULL,
1596			NULL, NULL);
1597	if (ret < 0 && ret != -ENOENT)
1598		goto out;
1599	left_ret = ret;
1600
1601	if (!sctx->parent_root) {
1602		right_ret = -ENOENT;
1603	} else {
1604		ret = get_inode_info(sctx->parent_root, ino, NULL, &right_gen,
1605				NULL, NULL, NULL, NULL);
1606		if (ret < 0 && ret != -ENOENT)
1607			goto out;
1608		right_ret = ret;
1609	}
1610
1611	if (!left_ret && !right_ret) {
1612		if (left_gen == gen && right_gen == gen) {
1613			ret = inode_state_no_change;
1614		} else if (left_gen == gen) {
1615			if (ino < sctx->send_progress)
1616				ret = inode_state_did_create;
1617			else
1618				ret = inode_state_will_create;
1619		} else if (right_gen == gen) {
1620			if (ino < sctx->send_progress)
1621				ret = inode_state_did_delete;
1622			else
1623				ret = inode_state_will_delete;
1624		} else  {
1625			ret = -ENOENT;
1626		}
1627	} else if (!left_ret) {
1628		if (left_gen == gen) {
1629			if (ino < sctx->send_progress)
1630				ret = inode_state_did_create;
1631			else
1632				ret = inode_state_will_create;
1633		} else {
1634			ret = -ENOENT;
1635		}
1636	} else if (!right_ret) {
1637		if (right_gen == gen) {
1638			if (ino < sctx->send_progress)
1639				ret = inode_state_did_delete;
1640			else
1641				ret = inode_state_will_delete;
1642		} else {
1643			ret = -ENOENT;
1644		}
1645	} else {
1646		ret = -ENOENT;
1647	}
1648
1649out:
1650	return ret;
1651}
1652
1653static int is_inode_existent(struct send_ctx *sctx, u64 ino, u64 gen)
1654{
1655	int ret;
1656
1657	if (ino == BTRFS_FIRST_FREE_OBJECTID)
1658		return 1;
1659
1660	ret = get_cur_inode_state(sctx, ino, gen);
1661	if (ret < 0)
1662		goto out;
1663
1664	if (ret == inode_state_no_change ||
1665	    ret == inode_state_did_create ||
1666	    ret == inode_state_will_delete)
1667		ret = 1;
1668	else
1669		ret = 0;
1670
1671out:
1672	return ret;
1673}
1674
1675/*
1676 * Helper function to lookup a dir item in a dir.
1677 */
1678static int lookup_dir_item_inode(struct btrfs_root *root,
1679				 u64 dir, const char *name, int name_len,
1680				 u64 *found_inode,
1681				 u8 *found_type)
1682{
1683	int ret = 0;
1684	struct btrfs_dir_item *di;
1685	struct btrfs_key key;
1686	struct btrfs_path *path;
1687
1688	path = alloc_path_for_send();
1689	if (!path)
1690		return -ENOMEM;
1691
1692	di = btrfs_lookup_dir_item(NULL, root, path,
1693			dir, name, name_len, 0);
1694	if (!di) {
1695		ret = -ENOENT;
1696		goto out;
1697	}
1698	if (IS_ERR(di)) {
1699		ret = PTR_ERR(di);
1700		goto out;
1701	}
1702	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
1703	if (key.type == BTRFS_ROOT_ITEM_KEY) {
1704		ret = -ENOENT;
1705		goto out;
1706	}
1707	*found_inode = key.objectid;
1708	*found_type = btrfs_dir_type(path->nodes[0], di);
1709
1710out:
1711	btrfs_free_path(path);
1712	return ret;
1713}
1714
1715/*
1716 * Looks up the first btrfs_inode_ref of a given ino. It returns the parent dir,
1717 * generation of the parent dir and the name of the dir entry.
1718 */
1719static int get_first_ref(struct btrfs_root *root, u64 ino,
1720			 u64 *dir, u64 *dir_gen, struct fs_path *name)
1721{
1722	int ret;
1723	struct btrfs_key key;
1724	struct btrfs_key found_key;
1725	struct btrfs_path *path;
1726	int len;
1727	u64 parent_dir;
1728
1729	path = alloc_path_for_send();
1730	if (!path)
1731		return -ENOMEM;
1732
1733	key.objectid = ino;
1734	key.type = BTRFS_INODE_REF_KEY;
1735	key.offset = 0;
1736
1737	ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
1738	if (ret < 0)
1739		goto out;
1740	if (!ret)
1741		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1742				path->slots[0]);
1743	if (ret || found_key.objectid != ino ||
1744	    (found_key.type != BTRFS_INODE_REF_KEY &&
1745	     found_key.type != BTRFS_INODE_EXTREF_KEY)) {
1746		ret = -ENOENT;
1747		goto out;
1748	}
1749
1750	if (found_key.type == BTRFS_INODE_REF_KEY) {
1751		struct btrfs_inode_ref *iref;
1752		iref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1753				      struct btrfs_inode_ref);
1754		len = btrfs_inode_ref_name_len(path->nodes[0], iref);
1755		ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
1756						     (unsigned long)(iref + 1),
1757						     len);
1758		parent_dir = found_key.offset;
1759	} else {
1760		struct btrfs_inode_extref *extref;
1761		extref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1762					struct btrfs_inode_extref);
1763		len = btrfs_inode_extref_name_len(path->nodes[0], extref);
1764		ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
1765					(unsigned long)&extref->name, len);
1766		parent_dir = btrfs_inode_extref_parent(path->nodes[0], extref);
1767	}
1768	if (ret < 0)
1769		goto out;
1770	btrfs_release_path(path);
1771
1772	if (dir_gen) {
1773		ret = get_inode_info(root, parent_dir, NULL, dir_gen, NULL,
1774				     NULL, NULL, NULL);
1775		if (ret < 0)
1776			goto out;
1777	}
1778
1779	*dir = parent_dir;
1780
1781out:
1782	btrfs_free_path(path);
1783	return ret;
1784}
1785
1786static int is_first_ref(struct btrfs_root *root,
1787			u64 ino, u64 dir,
1788			const char *name, int name_len)
1789{
1790	int ret;
1791	struct fs_path *tmp_name;
1792	u64 tmp_dir;
 
1793
1794	tmp_name = fs_path_alloc();
1795	if (!tmp_name)
1796		return -ENOMEM;
1797
1798	ret = get_first_ref(root, ino, &tmp_dir, NULL, tmp_name);
1799	if (ret < 0)
1800		goto out;
1801
1802	if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) {
1803		ret = 0;
1804		goto out;
1805	}
1806
1807	ret = !memcmp(tmp_name->start, name, name_len);
1808
1809out:
1810	fs_path_free(tmp_name);
1811	return ret;
1812}
1813
1814/*
1815 * Used by process_recorded_refs to determine if a new ref would overwrite an
1816 * already existing ref. In case it detects an overwrite, it returns the
1817 * inode/gen in who_ino/who_gen.
1818 * When an overwrite is detected, process_recorded_refs does proper orphanizing
1819 * to make sure later references to the overwritten inode are possible.
1820 * Orphanizing is however only required for the first ref of an inode.
1821 * process_recorded_refs does an additional is_first_ref check to see if
1822 * orphanizing is really required.
1823 */
1824static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
1825			      const char *name, int name_len,
1826			      u64 *who_ino, u64 *who_gen, u64 *who_mode)
1827{
1828	int ret = 0;
1829	u64 gen;
1830	u64 other_inode = 0;
1831	u8 other_type = 0;
1832
1833	if (!sctx->parent_root)
1834		goto out;
1835
1836	ret = is_inode_existent(sctx, dir, dir_gen);
1837	if (ret <= 0)
1838		goto out;
1839
1840	/*
1841	 * If we have a parent root we need to verify that the parent dir was
1842	 * not deleted and then re-created, if it was then we have no overwrite
1843	 * and we can just unlink this entry.
1844	 */
1845	if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID) {
1846		ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL,
1847				     NULL, NULL, NULL);
1848		if (ret < 0 && ret != -ENOENT)
1849			goto out;
1850		if (ret) {
1851			ret = 0;
1852			goto out;
1853		}
1854		if (gen != dir_gen)
1855			goto out;
1856	}
1857
1858	ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
1859			&other_inode, &other_type);
1860	if (ret < 0 && ret != -ENOENT)
1861		goto out;
1862	if (ret) {
1863		ret = 0;
1864		goto out;
1865	}
1866
1867	/*
1868	 * Check if the overwritten ref was already processed. If yes, the ref
1869	 * was already unlinked/moved, so we can safely assume that we will not
1870	 * overwrite anything at this point in time.
1871	 */
1872	if (other_inode > sctx->send_progress ||
1873	    is_waiting_for_move(sctx, other_inode)) {
1874		ret = get_inode_info(sctx->parent_root, other_inode, NULL,
1875				who_gen, who_mode, NULL, NULL, NULL);
1876		if (ret < 0)
1877			goto out;
1878
1879		ret = 1;
1880		*who_ino = other_inode;
1881	} else {
1882		ret = 0;
1883	}
1884
1885out:
1886	return ret;
1887}
1888
1889/*
1890 * Checks if the ref was overwritten by an already processed inode. This is
1891 * used by __get_cur_name_and_parent to find out if the ref was orphanized and
1892 * thus the orphan name needs be used.
1893 * process_recorded_refs also uses it to avoid unlinking of refs that were
1894 * overwritten.
1895 */
1896static int did_overwrite_ref(struct send_ctx *sctx,
1897			    u64 dir, u64 dir_gen,
1898			    u64 ino, u64 ino_gen,
1899			    const char *name, int name_len)
1900{
1901	int ret = 0;
1902	u64 gen;
1903	u64 ow_inode;
1904	u8 other_type;
1905
1906	if (!sctx->parent_root)
1907		goto out;
1908
1909	ret = is_inode_existent(sctx, dir, dir_gen);
1910	if (ret <= 0)
1911		goto out;
1912
1913	if (dir != BTRFS_FIRST_FREE_OBJECTID) {
1914		ret = get_inode_info(sctx->send_root, dir, NULL, &gen, NULL,
1915				     NULL, NULL, NULL);
1916		if (ret < 0 && ret != -ENOENT)
1917			goto out;
1918		if (ret) {
1919			ret = 0;
1920			goto out;
1921		}
1922		if (gen != dir_gen)
1923			goto out;
1924	}
1925
1926	/* check if the ref was overwritten by another ref */
1927	ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
1928			&ow_inode, &other_type);
1929	if (ret < 0 && ret != -ENOENT)
1930		goto out;
1931	if (ret) {
1932		/* was never and will never be overwritten */
1933		ret = 0;
1934		goto out;
1935	}
1936
1937	ret = get_inode_info(sctx->send_root, ow_inode, NULL, &gen, NULL, NULL,
1938			NULL, NULL);
1939	if (ret < 0)
1940		goto out;
1941
1942	if (ow_inode == ino && gen == ino_gen) {
1943		ret = 0;
1944		goto out;
1945	}
1946
1947	/*
1948	 * We know that it is or will be overwritten. Check this now.
1949	 * The current inode being processed might have been the one that caused
1950	 * inode 'ino' to be orphanized, therefore check if ow_inode matches
1951	 * the current inode being processed.
1952	 */
1953	if ((ow_inode < sctx->send_progress) ||
1954	    (ino != sctx->cur_ino && ow_inode == sctx->cur_ino &&
1955	     gen == sctx->cur_inode_gen))
1956		ret = 1;
1957	else
1958		ret = 0;
1959
1960out:
1961	return ret;
1962}
1963
1964/*
1965 * Same as did_overwrite_ref, but also checks if it is the first ref of an inode
1966 * that got overwritten. This is used by process_recorded_refs to determine
1967 * if it has to use the path as returned by get_cur_path or the orphan name.
1968 */
1969static int did_overwrite_first_ref(struct send_ctx *sctx, u64 ino, u64 gen)
1970{
1971	int ret = 0;
1972	struct fs_path *name = NULL;
1973	u64 dir;
1974	u64 dir_gen;
1975
1976	if (!sctx->parent_root)
1977		goto out;
1978
1979	name = fs_path_alloc();
1980	if (!name)
1981		return -ENOMEM;
1982
1983	ret = get_first_ref(sctx->parent_root, ino, &dir, &dir_gen, name);
1984	if (ret < 0)
1985		goto out;
1986
1987	ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen,
1988			name->start, fs_path_len(name));
1989
1990out:
1991	fs_path_free(name);
1992	return ret;
1993}
1994
1995/*
1996 * Insert a name cache entry. On 32bit kernels the radix tree index is 32bit,
1997 * so we need to do some special handling in case we have clashes. This function
1998 * takes care of this with the help of name_cache_entry::radix_list.
1999 * In case of error, nce is kfreed.
2000 */
2001static int name_cache_insert(struct send_ctx *sctx,
2002			     struct name_cache_entry *nce)
2003{
2004	int ret = 0;
2005	struct list_head *nce_head;
2006
2007	nce_head = radix_tree_lookup(&sctx->name_cache,
2008			(unsigned long)nce->ino);
2009	if (!nce_head) {
2010		nce_head = kmalloc(sizeof(*nce_head), GFP_KERNEL);
2011		if (!nce_head) {
2012			kfree(nce);
2013			return -ENOMEM;
2014		}
2015		INIT_LIST_HEAD(nce_head);
2016
2017		ret = radix_tree_insert(&sctx->name_cache, nce->ino, nce_head);
2018		if (ret < 0) {
2019			kfree(nce_head);
2020			kfree(nce);
2021			return ret;
2022		}
2023	}
2024	list_add_tail(&nce->radix_list, nce_head);
2025	list_add_tail(&nce->list, &sctx->name_cache_list);
2026	sctx->name_cache_size++;
2027
2028	return ret;
2029}
2030
2031static void name_cache_delete(struct send_ctx *sctx,
2032			      struct name_cache_entry *nce)
2033{
2034	struct list_head *nce_head;
2035
2036	nce_head = radix_tree_lookup(&sctx->name_cache,
2037			(unsigned long)nce->ino);
2038	if (!nce_head) {
2039		btrfs_err(sctx->send_root->fs_info,
2040	      "name_cache_delete lookup failed ino %llu cache size %d, leaking memory",
2041			nce->ino, sctx->name_cache_size);
2042	}
2043
2044	list_del(&nce->radix_list);
2045	list_del(&nce->list);
2046	sctx->name_cache_size--;
2047
2048	/*
2049	 * We may not get to the final release of nce_head if the lookup fails
2050	 */
2051	if (nce_head && list_empty(nce_head)) {
2052		radix_tree_delete(&sctx->name_cache, (unsigned long)nce->ino);
2053		kfree(nce_head);
2054	}
2055}
2056
2057static struct name_cache_entry *name_cache_search(struct send_ctx *sctx,
2058						    u64 ino, u64 gen)
2059{
2060	struct list_head *nce_head;
2061	struct name_cache_entry *cur;
2062
2063	nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)ino);
2064	if (!nce_head)
2065		return NULL;
2066
2067	list_for_each_entry(cur, nce_head, radix_list) {
2068		if (cur->ino == ino && cur->gen == gen)
2069			return cur;
2070	}
2071	return NULL;
2072}
2073
2074/*
2075 * Removes the entry from the list and adds it back to the end. This marks the
2076 * entry as recently used so that name_cache_clean_unused does not remove it.
2077 */
2078static void name_cache_used(struct send_ctx *sctx, struct name_cache_entry *nce)
2079{
2080	list_del(&nce->list);
2081	list_add_tail(&nce->list, &sctx->name_cache_list);
2082}
2083
2084/*
2085 * Remove some entries from the beginning of name_cache_list.
2086 */
2087static void name_cache_clean_unused(struct send_ctx *sctx)
2088{
2089	struct name_cache_entry *nce;
2090
2091	if (sctx->name_cache_size < SEND_CTX_NAME_CACHE_CLEAN_SIZE)
2092		return;
2093
2094	while (sctx->name_cache_size > SEND_CTX_MAX_NAME_CACHE_SIZE) {
2095		nce = list_entry(sctx->name_cache_list.next,
2096				struct name_cache_entry, list);
2097		name_cache_delete(sctx, nce);
2098		kfree(nce);
2099	}
2100}
2101
2102static void name_cache_free(struct send_ctx *sctx)
2103{
2104	struct name_cache_entry *nce;
2105
2106	while (!list_empty(&sctx->name_cache_list)) {
2107		nce = list_entry(sctx->name_cache_list.next,
2108				struct name_cache_entry, list);
2109		name_cache_delete(sctx, nce);
2110		kfree(nce);
2111	}
2112}
2113
2114/*
2115 * Used by get_cur_path for each ref up to the root.
2116 * Returns 0 if it succeeded.
2117 * Returns 1 if the inode is not existent or got overwritten. In that case, the
2118 * name is an orphan name. This instructs get_cur_path to stop iterating. If 1
2119 * is returned, parent_ino/parent_gen are not guaranteed to be valid.
2120 * Returns <0 in case of error.
2121 */
2122static int __get_cur_name_and_parent(struct send_ctx *sctx,
2123				     u64 ino, u64 gen,
2124				     u64 *parent_ino,
2125				     u64 *parent_gen,
2126				     struct fs_path *dest)
2127{
2128	int ret;
2129	int nce_ret;
 
2130	struct name_cache_entry *nce = NULL;
2131
2132	/*
2133	 * First check if we already did a call to this function with the same
2134	 * ino/gen. If yes, check if the cache entry is still up-to-date. If yes
2135	 * return the cached result.
2136	 */
2137	nce = name_cache_search(sctx, ino, gen);
2138	if (nce) {
2139		if (ino < sctx->send_progress && nce->need_later_update) {
2140			name_cache_delete(sctx, nce);
2141			kfree(nce);
2142			nce = NULL;
2143		} else {
2144			name_cache_used(sctx, nce);
2145			*parent_ino = nce->parent_ino;
2146			*parent_gen = nce->parent_gen;
2147			ret = fs_path_add(dest, nce->name, nce->name_len);
2148			if (ret < 0)
2149				goto out;
2150			ret = nce->ret;
2151			goto out;
2152		}
2153	}
2154
 
 
 
 
2155	/*
2156	 * If the inode is not existent yet, add the orphan name and return 1.
2157	 * This should only happen for the parent dir that we determine in
2158	 * __record_new_ref
2159	 */
2160	ret = is_inode_existent(sctx, ino, gen);
2161	if (ret < 0)
2162		goto out;
2163
2164	if (!ret) {
2165		ret = gen_unique_name(sctx, ino, gen, dest);
2166		if (ret < 0)
2167			goto out;
2168		ret = 1;
2169		goto out_cache;
2170	}
2171
2172	/*
2173	 * Depending on whether the inode was already processed or not, use
2174	 * send_root or parent_root for ref lookup.
2175	 */
2176	if (ino < sctx->send_progress)
2177		ret = get_first_ref(sctx->send_root, ino,
2178				    parent_ino, parent_gen, dest);
2179	else
2180		ret = get_first_ref(sctx->parent_root, ino,
2181				    parent_ino, parent_gen, dest);
2182	if (ret < 0)
2183		goto out;
2184
2185	/*
2186	 * Check if the ref was overwritten by an inode's ref that was processed
2187	 * earlier. If yes, treat as orphan and return 1.
2188	 */
2189	ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen,
2190			dest->start, dest->end - dest->start);
2191	if (ret < 0)
2192		goto out;
2193	if (ret) {
2194		fs_path_reset(dest);
2195		ret = gen_unique_name(sctx, ino, gen, dest);
2196		if (ret < 0)
2197			goto out;
2198		ret = 1;
2199	}
2200
2201out_cache:
2202	/*
2203	 * Store the result of the lookup in the name cache.
2204	 */
2205	nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_KERNEL);
2206	if (!nce) {
2207		ret = -ENOMEM;
2208		goto out;
2209	}
2210
2211	nce->ino = ino;
2212	nce->gen = gen;
2213	nce->parent_ino = *parent_ino;
2214	nce->parent_gen = *parent_gen;
2215	nce->name_len = fs_path_len(dest);
2216	nce->ret = ret;
2217	strcpy(nce->name, dest->start);
2218
2219	if (ino < sctx->send_progress)
2220		nce->need_later_update = 0;
2221	else
2222		nce->need_later_update = 1;
2223
2224	nce_ret = name_cache_insert(sctx, nce);
2225	if (nce_ret < 0)
2226		ret = nce_ret;
2227	name_cache_clean_unused(sctx);
2228
2229out:
 
2230	return ret;
2231}
2232
2233/*
2234 * Magic happens here. This function returns the first ref to an inode as it
2235 * would look like while receiving the stream at this point in time.
2236 * We walk the path up to the root. For every inode in between, we check if it
2237 * was already processed/sent. If yes, we continue with the parent as found
2238 * in send_root. If not, we continue with the parent as found in parent_root.
2239 * If we encounter an inode that was deleted at this point in time, we use the
2240 * inodes "orphan" name instead of the real name and stop. Same with new inodes
2241 * that were not created yet and overwritten inodes/refs.
2242 *
2243 * When do we have have orphan inodes:
2244 * 1. When an inode is freshly created and thus no valid refs are available yet
2245 * 2. When a directory lost all it's refs (deleted) but still has dir items
2246 *    inside which were not processed yet (pending for move/delete). If anyone
2247 *    tried to get the path to the dir items, it would get a path inside that
2248 *    orphan directory.
2249 * 3. When an inode is moved around or gets new links, it may overwrite the ref
2250 *    of an unprocessed inode. If in that case the first ref would be
2251 *    overwritten, the overwritten inode gets "orphanized". Later when we
2252 *    process this overwritten inode, it is restored at a new place by moving
2253 *    the orphan inode.
2254 *
2255 * sctx->send_progress tells this function at which point in time receiving
2256 * would be.
2257 */
2258static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
2259			struct fs_path *dest)
2260{
2261	int ret = 0;
2262	struct fs_path *name = NULL;
2263	u64 parent_inode = 0;
2264	u64 parent_gen = 0;
2265	int stop = 0;
2266
2267	name = fs_path_alloc();
2268	if (!name) {
2269		ret = -ENOMEM;
2270		goto out;
2271	}
2272
2273	dest->reversed = 1;
2274	fs_path_reset(dest);
2275
2276	while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) {
2277		struct waiting_dir_move *wdm;
2278
2279		fs_path_reset(name);
2280
2281		if (is_waiting_for_rm(sctx, ino)) {
2282			ret = gen_unique_name(sctx, ino, gen, name);
2283			if (ret < 0)
2284				goto out;
2285			ret = fs_path_add_path(dest, name);
2286			break;
2287		}
2288
2289		wdm = get_waiting_dir_move(sctx, ino);
2290		if (wdm && wdm->orphanized) {
2291			ret = gen_unique_name(sctx, ino, gen, name);
2292			stop = 1;
2293		} else if (wdm) {
2294			ret = get_first_ref(sctx->parent_root, ino,
2295					    &parent_inode, &parent_gen, name);
2296		} else {
2297			ret = __get_cur_name_and_parent(sctx, ino, gen,
2298							&parent_inode,
2299							&parent_gen, name);
2300			if (ret)
2301				stop = 1;
2302		}
2303
2304		if (ret < 0)
2305			goto out;
2306
2307		ret = fs_path_add_path(dest, name);
2308		if (ret < 0)
2309			goto out;
2310
2311		ino = parent_inode;
2312		gen = parent_gen;
2313	}
2314
2315out:
2316	fs_path_free(name);
2317	if (!ret)
2318		fs_path_unreverse(dest);
2319	return ret;
2320}
2321
2322/*
2323 * Sends a BTRFS_SEND_C_SUBVOL command/item to userspace
2324 */
2325static int send_subvol_begin(struct send_ctx *sctx)
2326{
2327	int ret;
2328	struct btrfs_root *send_root = sctx->send_root;
2329	struct btrfs_root *parent_root = sctx->parent_root;
2330	struct btrfs_path *path;
2331	struct btrfs_key key;
2332	struct btrfs_root_ref *ref;
2333	struct extent_buffer *leaf;
2334	char *name = NULL;
2335	int namelen;
2336
2337	path = btrfs_alloc_path();
2338	if (!path)
2339		return -ENOMEM;
2340
2341	name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL);
2342	if (!name) {
2343		btrfs_free_path(path);
2344		return -ENOMEM;
2345	}
2346
2347	key.objectid = send_root->objectid;
2348	key.type = BTRFS_ROOT_BACKREF_KEY;
2349	key.offset = 0;
2350
2351	ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root,
2352				&key, path, 1, 0);
2353	if (ret < 0)
2354		goto out;
2355	if (ret) {
2356		ret = -ENOENT;
2357		goto out;
2358	}
2359
2360	leaf = path->nodes[0];
2361	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2362	if (key.type != BTRFS_ROOT_BACKREF_KEY ||
2363	    key.objectid != send_root->objectid) {
2364		ret = -ENOENT;
2365		goto out;
2366	}
2367	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
2368	namelen = btrfs_root_ref_name_len(leaf, ref);
2369	read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen);
2370	btrfs_release_path(path);
2371
2372	if (parent_root) {
2373		ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT);
2374		if (ret < 0)
2375			goto out;
2376	} else {
2377		ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL);
2378		if (ret < 0)
2379			goto out;
2380	}
2381
2382	TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen);
2383
2384	if (!btrfs_is_empty_uuid(sctx->send_root->root_item.received_uuid))
2385		TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
2386			    sctx->send_root->root_item.received_uuid);
2387	else
2388		TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
2389			    sctx->send_root->root_item.uuid);
2390
2391	TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID,
2392		    le64_to_cpu(sctx->send_root->root_item.ctransid));
2393	if (parent_root) {
2394		if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid))
2395			TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
2396				     parent_root->root_item.received_uuid);
2397		else
2398			TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
2399				     parent_root->root_item.uuid);
2400		TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
2401			    le64_to_cpu(sctx->parent_root->root_item.ctransid));
2402	}
2403
2404	ret = send_cmd(sctx);
2405
2406tlv_put_failure:
2407out:
2408	btrfs_free_path(path);
2409	kfree(name);
2410	return ret;
2411}
2412
2413static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size)
2414{
2415	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2416	int ret = 0;
2417	struct fs_path *p;
2418
2419	btrfs_debug(fs_info, "send_truncate %llu size=%llu", ino, size);
2420
2421	p = fs_path_alloc();
2422	if (!p)
2423		return -ENOMEM;
2424
2425	ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE);
2426	if (ret < 0)
2427		goto out;
2428
2429	ret = get_cur_path(sctx, ino, gen, p);
2430	if (ret < 0)
2431		goto out;
2432	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2433	TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size);
2434
2435	ret = send_cmd(sctx);
2436
2437tlv_put_failure:
2438out:
2439	fs_path_free(p);
2440	return ret;
2441}
2442
2443static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode)
2444{
2445	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2446	int ret = 0;
2447	struct fs_path *p;
2448
2449	btrfs_debug(fs_info, "send_chmod %llu mode=%llu", ino, mode);
2450
2451	p = fs_path_alloc();
2452	if (!p)
2453		return -ENOMEM;
2454
2455	ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD);
2456	if (ret < 0)
2457		goto out;
2458
2459	ret = get_cur_path(sctx, ino, gen, p);
2460	if (ret < 0)
2461		goto out;
2462	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2463	TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777);
2464
2465	ret = send_cmd(sctx);
2466
2467tlv_put_failure:
2468out:
2469	fs_path_free(p);
2470	return ret;
2471}
2472
2473static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid)
2474{
2475	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2476	int ret = 0;
2477	struct fs_path *p;
2478
2479	btrfs_debug(fs_info, "send_chown %llu uid=%llu, gid=%llu",
2480		    ino, uid, gid);
2481
2482	p = fs_path_alloc();
2483	if (!p)
2484		return -ENOMEM;
2485
2486	ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN);
2487	if (ret < 0)
2488		goto out;
2489
2490	ret = get_cur_path(sctx, ino, gen, p);
2491	if (ret < 0)
2492		goto out;
2493	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2494	TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid);
2495	TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid);
2496
2497	ret = send_cmd(sctx);
2498
2499tlv_put_failure:
2500out:
2501	fs_path_free(p);
2502	return ret;
2503}
2504
2505static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen)
2506{
2507	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2508	int ret = 0;
2509	struct fs_path *p = NULL;
2510	struct btrfs_inode_item *ii;
2511	struct btrfs_path *path = NULL;
2512	struct extent_buffer *eb;
2513	struct btrfs_key key;
2514	int slot;
2515
2516	btrfs_debug(fs_info, "send_utimes %llu", ino);
2517
2518	p = fs_path_alloc();
2519	if (!p)
2520		return -ENOMEM;
2521
2522	path = alloc_path_for_send();
2523	if (!path) {
2524		ret = -ENOMEM;
2525		goto out;
2526	}
2527
2528	key.objectid = ino;
2529	key.type = BTRFS_INODE_ITEM_KEY;
2530	key.offset = 0;
2531	ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
2532	if (ret > 0)
2533		ret = -ENOENT;
2534	if (ret < 0)
2535		goto out;
2536
2537	eb = path->nodes[0];
2538	slot = path->slots[0];
2539	ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);
2540
2541	ret = begin_cmd(sctx, BTRFS_SEND_C_UTIMES);
2542	if (ret < 0)
2543		goto out;
2544
2545	ret = get_cur_path(sctx, ino, gen, p);
2546	if (ret < 0)
2547		goto out;
2548	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2549	TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, eb, &ii->atime);
2550	TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb, &ii->mtime);
2551	TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb, &ii->ctime);
 
 
 
2552	/* TODO Add otime support when the otime patches get into upstream */
2553
2554	ret = send_cmd(sctx);
2555
2556tlv_put_failure:
2557out:
2558	fs_path_free(p);
2559	btrfs_free_path(path);
2560	return ret;
2561}
2562
2563/*
2564 * Sends a BTRFS_SEND_C_MKXXX or SYMLINK command to user space. We don't have
2565 * a valid path yet because we did not process the refs yet. So, the inode
2566 * is created as orphan.
2567 */
2568static int send_create_inode(struct send_ctx *sctx, u64 ino)
2569{
2570	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
2571	int ret = 0;
2572	struct fs_path *p;
2573	int cmd;
2574	u64 gen;
2575	u64 mode;
2576	u64 rdev;
2577
2578	btrfs_debug(fs_info, "send_create_inode %llu", ino);
2579
2580	p = fs_path_alloc();
2581	if (!p)
2582		return -ENOMEM;
2583
2584	if (ino != sctx->cur_ino) {
2585		ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode,
2586				     NULL, NULL, &rdev);
2587		if (ret < 0)
2588			goto out;
2589	} else {
2590		gen = sctx->cur_inode_gen;
2591		mode = sctx->cur_inode_mode;
2592		rdev = sctx->cur_inode_rdev;
2593	}
2594
2595	if (S_ISREG(mode)) {
2596		cmd = BTRFS_SEND_C_MKFILE;
2597	} else if (S_ISDIR(mode)) {
2598		cmd = BTRFS_SEND_C_MKDIR;
2599	} else if (S_ISLNK(mode)) {
2600		cmd = BTRFS_SEND_C_SYMLINK;
2601	} else if (S_ISCHR(mode) || S_ISBLK(mode)) {
2602		cmd = BTRFS_SEND_C_MKNOD;
2603	} else if (S_ISFIFO(mode)) {
2604		cmd = BTRFS_SEND_C_MKFIFO;
2605	} else if (S_ISSOCK(mode)) {
2606		cmd = BTRFS_SEND_C_MKSOCK;
2607	} else {
2608		btrfs_warn(sctx->send_root->fs_info, "unexpected inode type %o",
2609				(int)(mode & S_IFMT));
2610		ret = -EOPNOTSUPP;
2611		goto out;
2612	}
2613
2614	ret = begin_cmd(sctx, cmd);
2615	if (ret < 0)
2616		goto out;
2617
2618	ret = gen_unique_name(sctx, ino, gen, p);
2619	if (ret < 0)
2620		goto out;
2621
2622	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2623	TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino);
2624
2625	if (S_ISLNK(mode)) {
2626		fs_path_reset(p);
2627		ret = read_symlink(sctx->send_root, ino, p);
2628		if (ret < 0)
2629			goto out;
2630		TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p);
2631	} else if (S_ISCHR(mode) || S_ISBLK(mode) ||
2632		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
2633		TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, new_encode_dev(rdev));
2634		TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode);
2635	}
2636
2637	ret = send_cmd(sctx);
2638	if (ret < 0)
2639		goto out;
2640
2641
2642tlv_put_failure:
2643out:
2644	fs_path_free(p);
2645	return ret;
2646}
2647
2648/*
2649 * We need some special handling for inodes that get processed before the parent
2650 * directory got created. See process_recorded_refs for details.
2651 * This function does the check if we already created the dir out of order.
2652 */
2653static int did_create_dir(struct send_ctx *sctx, u64 dir)
2654{
2655	int ret = 0;
2656	struct btrfs_path *path = NULL;
2657	struct btrfs_key key;
2658	struct btrfs_key found_key;
2659	struct btrfs_key di_key;
2660	struct extent_buffer *eb;
2661	struct btrfs_dir_item *di;
2662	int slot;
2663
2664	path = alloc_path_for_send();
2665	if (!path) {
2666		ret = -ENOMEM;
2667		goto out;
2668	}
2669
2670	key.objectid = dir;
2671	key.type = BTRFS_DIR_INDEX_KEY;
2672	key.offset = 0;
2673	ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
2674	if (ret < 0)
2675		goto out;
2676
2677	while (1) {
2678		eb = path->nodes[0];
2679		slot = path->slots[0];
2680		if (slot >= btrfs_header_nritems(eb)) {
2681			ret = btrfs_next_leaf(sctx->send_root, path);
2682			if (ret < 0) {
2683				goto out;
2684			} else if (ret > 0) {
2685				ret = 0;
2686				break;
2687			}
2688			continue;
2689		}
2690
2691		btrfs_item_key_to_cpu(eb, &found_key, slot);
2692		if (found_key.objectid != key.objectid ||
2693		    found_key.type != key.type) {
2694			ret = 0;
2695			goto out;
2696		}
2697
2698		di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
2699		btrfs_dir_item_key_to_cpu(eb, di, &di_key);
2700
2701		if (di_key.type != BTRFS_ROOT_ITEM_KEY &&
2702		    di_key.objectid < sctx->send_progress) {
2703			ret = 1;
2704			goto out;
2705		}
2706
2707		path->slots[0]++;
2708	}
2709
2710out:
2711	btrfs_free_path(path);
2712	return ret;
2713}
2714
2715/*
2716 * Only creates the inode if it is:
2717 * 1. Not a directory
2718 * 2. Or a directory which was not created already due to out of order
2719 *    directories. See did_create_dir and process_recorded_refs for details.
2720 */
2721static int send_create_inode_if_needed(struct send_ctx *sctx)
2722{
2723	int ret;
2724
2725	if (S_ISDIR(sctx->cur_inode_mode)) {
2726		ret = did_create_dir(sctx, sctx->cur_ino);
2727		if (ret < 0)
2728			goto out;
2729		if (ret) {
2730			ret = 0;
2731			goto out;
2732		}
2733	}
2734
2735	ret = send_create_inode(sctx, sctx->cur_ino);
2736	if (ret < 0)
2737		goto out;
2738
2739out:
2740	return ret;
2741}
2742
2743struct recorded_ref {
2744	struct list_head list;
 
2745	char *name;
2746	struct fs_path *full_path;
2747	u64 dir;
2748	u64 dir_gen;
 
2749	int name_len;
2750};
2751
2752static void set_ref_path(struct recorded_ref *ref, struct fs_path *path)
2753{
2754	ref->full_path = path;
2755	ref->name = (char *)kbasename(ref->full_path->start);
2756	ref->name_len = ref->full_path->end - ref->name;
2757}
2758
2759/*
2760 * We need to process new refs before deleted refs, but compare_tree gives us
2761 * everything mixed. So we first record all refs and later process them.
2762 * This function is a helper to record one ref.
2763 */
2764static int __record_ref(struct list_head *head, u64 dir,
2765		      u64 dir_gen, struct fs_path *path)
2766{
2767	struct recorded_ref *ref;
2768
2769	ref = kmalloc(sizeof(*ref), GFP_KERNEL);
2770	if (!ref)
2771		return -ENOMEM;
2772
2773	ref->dir = dir;
2774	ref->dir_gen = dir_gen;
2775	set_ref_path(ref, path);
 
 
 
 
 
 
 
 
 
 
2776	list_add_tail(&ref->list, head);
2777	return 0;
2778}
2779
2780static int dup_ref(struct recorded_ref *ref, struct list_head *list)
2781{
2782	struct recorded_ref *new;
2783
2784	new = kmalloc(sizeof(*ref), GFP_KERNEL);
2785	if (!new)
2786		return -ENOMEM;
2787
2788	new->dir = ref->dir;
2789	new->dir_gen = ref->dir_gen;
2790	new->full_path = NULL;
2791	INIT_LIST_HEAD(&new->list);
2792	list_add_tail(&new->list, list);
2793	return 0;
2794}
2795
2796static void __free_recorded_refs(struct list_head *head)
2797{
2798	struct recorded_ref *cur;
2799
2800	while (!list_empty(head)) {
2801		cur = list_entry(head->next, struct recorded_ref, list);
2802		fs_path_free(cur->full_path);
2803		list_del(&cur->list);
2804		kfree(cur);
2805	}
2806}
2807
2808static void free_recorded_refs(struct send_ctx *sctx)
2809{
2810	__free_recorded_refs(&sctx->new_refs);
2811	__free_recorded_refs(&sctx->deleted_refs);
2812}
2813
2814/*
2815 * Renames/moves a file/dir to its orphan name. Used when the first
2816 * ref of an unprocessed inode gets overwritten and for all non empty
2817 * directories.
2818 */
2819static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen,
2820			  struct fs_path *path)
2821{
2822	int ret;
2823	struct fs_path *orphan;
2824
2825	orphan = fs_path_alloc();
2826	if (!orphan)
2827		return -ENOMEM;
2828
2829	ret = gen_unique_name(sctx, ino, gen, orphan);
2830	if (ret < 0)
2831		goto out;
2832
2833	ret = send_rename(sctx, path, orphan);
2834
2835out:
2836	fs_path_free(orphan);
2837	return ret;
2838}
2839
2840static struct orphan_dir_info *
2841add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino)
2842{
2843	struct rb_node **p = &sctx->orphan_dirs.rb_node;
2844	struct rb_node *parent = NULL;
2845	struct orphan_dir_info *entry, *odi;
2846
2847	odi = kmalloc(sizeof(*odi), GFP_KERNEL);
2848	if (!odi)
2849		return ERR_PTR(-ENOMEM);
2850	odi->ino = dir_ino;
2851	odi->gen = 0;
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 {
2861			kfree(odi);
2862			return entry;
2863		}
2864	}
2865
2866	rb_link_node(&odi->node, parent, p);
2867	rb_insert_color(&odi->node, &sctx->orphan_dirs);
2868	return odi;
2869}
2870
2871static struct orphan_dir_info *
2872get_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino)
2873{
2874	struct rb_node *n = sctx->orphan_dirs.rb_node;
2875	struct orphan_dir_info *entry;
2876
2877	while (n) {
2878		entry = rb_entry(n, struct orphan_dir_info, node);
2879		if (dir_ino < entry->ino)
2880			n = n->rb_left;
2881		else if (dir_ino > entry->ino)
2882			n = n->rb_right;
2883		else
2884			return entry;
2885	}
2886	return NULL;
2887}
2888
2889static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino)
2890{
2891	struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino);
2892
2893	return odi != NULL;
2894}
2895
2896static void free_orphan_dir_info(struct send_ctx *sctx,
2897				 struct orphan_dir_info *odi)
2898{
2899	if (!odi)
2900		return;
2901	rb_erase(&odi->node, &sctx->orphan_dirs);
2902	kfree(odi);
2903}
2904
2905/*
2906 * Returns 1 if a directory can be removed at this point in time.
2907 * We check this by iterating all dir items and checking if the inode behind
2908 * the dir item was already processed.
2909 */
2910static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen,
2911		     u64 send_progress)
2912{
2913	int ret = 0;
2914	struct btrfs_root *root = sctx->parent_root;
2915	struct btrfs_path *path;
2916	struct btrfs_key key;
2917	struct btrfs_key found_key;
2918	struct btrfs_key loc;
2919	struct btrfs_dir_item *di;
2920
2921	/*
2922	 * Don't try to rmdir the top/root subvolume dir.
2923	 */
2924	if (dir == BTRFS_FIRST_FREE_OBJECTID)
2925		return 0;
2926
2927	path = alloc_path_for_send();
2928	if (!path)
2929		return -ENOMEM;
2930
2931	key.objectid = dir;
2932	key.type = BTRFS_DIR_INDEX_KEY;
2933	key.offset = 0;
2934	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2935	if (ret < 0)
2936		goto out;
2937
2938	while (1) {
2939		struct waiting_dir_move *dm;
2940
2941		if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
2942			ret = btrfs_next_leaf(root, path);
2943			if (ret < 0)
2944				goto out;
2945			else if (ret > 0)
2946				break;
2947			continue;
2948		}
2949		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2950				      path->slots[0]);
2951		if (found_key.objectid != key.objectid ||
2952		    found_key.type != key.type)
2953			break;
2954
2955		di = btrfs_item_ptr(path->nodes[0], path->slots[0],
2956				struct btrfs_dir_item);
2957		btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc);
2958
2959		dm = get_waiting_dir_move(sctx, loc.objectid);
2960		if (dm) {
2961			struct orphan_dir_info *odi;
2962
2963			odi = add_orphan_dir_info(sctx, dir);
2964			if (IS_ERR(odi)) {
2965				ret = PTR_ERR(odi);
2966				goto out;
2967			}
2968			odi->gen = dir_gen;
2969			dm->rmdir_ino = dir;
2970			ret = 0;
2971			goto out;
2972		}
2973
2974		if (loc.objectid > send_progress) {
2975			struct orphan_dir_info *odi;
2976
2977			odi = get_orphan_dir_info(sctx, dir);
2978			free_orphan_dir_info(sctx, odi);
2979			ret = 0;
2980			goto out;
2981		}
2982
2983		path->slots[0]++;
2984	}
2985
2986	ret = 1;
2987
2988out:
2989	btrfs_free_path(path);
2990	return ret;
2991}
2992
2993static int is_waiting_for_move(struct send_ctx *sctx, u64 ino)
2994{
2995	struct waiting_dir_move *entry = get_waiting_dir_move(sctx, ino);
2996
2997	return entry != NULL;
2998}
2999
3000static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino, bool orphanized)
3001{
3002	struct rb_node **p = &sctx->waiting_dir_moves.rb_node;
3003	struct rb_node *parent = NULL;
3004	struct waiting_dir_move *entry, *dm;
3005
3006	dm = kmalloc(sizeof(*dm), GFP_KERNEL);
3007	if (!dm)
3008		return -ENOMEM;
3009	dm->ino = ino;
3010	dm->rmdir_ino = 0;
3011	dm->orphanized = orphanized;
3012
3013	while (*p) {
3014		parent = *p;
3015		entry = rb_entry(parent, struct waiting_dir_move, node);
3016		if (ino < entry->ino) {
3017			p = &(*p)->rb_left;
3018		} else if (ino > entry->ino) {
3019			p = &(*p)->rb_right;
3020		} else {
3021			kfree(dm);
3022			return -EEXIST;
3023		}
3024	}
3025
3026	rb_link_node(&dm->node, parent, p);
3027	rb_insert_color(&dm->node, &sctx->waiting_dir_moves);
3028	return 0;
3029}
3030
3031static struct waiting_dir_move *
3032get_waiting_dir_move(struct send_ctx *sctx, u64 ino)
3033{
3034	struct rb_node *n = sctx->waiting_dir_moves.rb_node;
3035	struct waiting_dir_move *entry;
3036
3037	while (n) {
3038		entry = rb_entry(n, struct waiting_dir_move, node);
3039		if (ino < entry->ino)
3040			n = n->rb_left;
3041		else if (ino > entry->ino)
3042			n = n->rb_right;
3043		else
3044			return entry;
3045	}
3046	return NULL;
3047}
3048
3049static void free_waiting_dir_move(struct send_ctx *sctx,
3050				  struct waiting_dir_move *dm)
3051{
3052	if (!dm)
3053		return;
3054	rb_erase(&dm->node, &sctx->waiting_dir_moves);
3055	kfree(dm);
3056}
3057
3058static int add_pending_dir_move(struct send_ctx *sctx,
3059				u64 ino,
3060				u64 ino_gen,
3061				u64 parent_ino,
3062				struct list_head *new_refs,
3063				struct list_head *deleted_refs,
3064				const bool is_orphan)
3065{
3066	struct rb_node **p = &sctx->pending_dir_moves.rb_node;
3067	struct rb_node *parent = NULL;
3068	struct pending_dir_move *entry = NULL, *pm;
3069	struct recorded_ref *cur;
3070	int exists = 0;
3071	int ret;
3072
3073	pm = kmalloc(sizeof(*pm), GFP_KERNEL);
3074	if (!pm)
3075		return -ENOMEM;
3076	pm->parent_ino = parent_ino;
3077	pm->ino = ino;
3078	pm->gen = ino_gen;
3079	INIT_LIST_HEAD(&pm->list);
3080	INIT_LIST_HEAD(&pm->update_refs);
3081	RB_CLEAR_NODE(&pm->node);
3082
3083	while (*p) {
3084		parent = *p;
3085		entry = rb_entry(parent, struct pending_dir_move, node);
3086		if (parent_ino < entry->parent_ino) {
3087			p = &(*p)->rb_left;
3088		} else if (parent_ino > entry->parent_ino) {
3089			p = &(*p)->rb_right;
3090		} else {
3091			exists = 1;
3092			break;
3093		}
3094	}
3095
3096	list_for_each_entry(cur, deleted_refs, list) {
3097		ret = dup_ref(cur, &pm->update_refs);
3098		if (ret < 0)
3099			goto out;
3100	}
3101	list_for_each_entry(cur, new_refs, list) {
3102		ret = dup_ref(cur, &pm->update_refs);
3103		if (ret < 0)
3104			goto out;
3105	}
3106
3107	ret = add_waiting_dir_move(sctx, pm->ino, is_orphan);
3108	if (ret)
3109		goto out;
3110
3111	if (exists) {
3112		list_add_tail(&pm->list, &entry->list);
3113	} else {
3114		rb_link_node(&pm->node, parent, p);
3115		rb_insert_color(&pm->node, &sctx->pending_dir_moves);
3116	}
3117	ret = 0;
3118out:
3119	if (ret) {
3120		__free_recorded_refs(&pm->update_refs);
3121		kfree(pm);
3122	}
3123	return ret;
3124}
3125
3126static struct pending_dir_move *get_pending_dir_moves(struct send_ctx *sctx,
3127						      u64 parent_ino)
3128{
3129	struct rb_node *n = sctx->pending_dir_moves.rb_node;
3130	struct pending_dir_move *entry;
3131
3132	while (n) {
3133		entry = rb_entry(n, struct pending_dir_move, node);
3134		if (parent_ino < entry->parent_ino)
3135			n = n->rb_left;
3136		else if (parent_ino > entry->parent_ino)
3137			n = n->rb_right;
3138		else
3139			return entry;
3140	}
3141	return NULL;
3142}
3143
3144static int path_loop(struct send_ctx *sctx, struct fs_path *name,
3145		     u64 ino, u64 gen, u64 *ancestor_ino)
3146{
3147	int ret = 0;
3148	u64 parent_inode = 0;
3149	u64 parent_gen = 0;
3150	u64 start_ino = ino;
3151
3152	*ancestor_ino = 0;
3153	while (ino != BTRFS_FIRST_FREE_OBJECTID) {
3154		fs_path_reset(name);
3155
3156		if (is_waiting_for_rm(sctx, ino))
3157			break;
3158		if (is_waiting_for_move(sctx, ino)) {
3159			if (*ancestor_ino == 0)
3160				*ancestor_ino = ino;
3161			ret = get_first_ref(sctx->parent_root, ino,
3162					    &parent_inode, &parent_gen, name);
3163		} else {
3164			ret = __get_cur_name_and_parent(sctx, ino, gen,
3165							&parent_inode,
3166							&parent_gen, name);
3167			if (ret > 0) {
3168				ret = 0;
3169				break;
3170			}
3171		}
3172		if (ret < 0)
3173			break;
3174		if (parent_inode == start_ino) {
3175			ret = 1;
3176			if (*ancestor_ino == 0)
3177				*ancestor_ino = ino;
3178			break;
3179		}
3180		ino = parent_inode;
3181		gen = parent_gen;
3182	}
3183	return ret;
3184}
3185
3186static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm)
3187{
3188	struct fs_path *from_path = NULL;
3189	struct fs_path *to_path = NULL;
3190	struct fs_path *name = NULL;
3191	u64 orig_progress = sctx->send_progress;
3192	struct recorded_ref *cur;
3193	u64 parent_ino, parent_gen;
3194	struct waiting_dir_move *dm = NULL;
3195	u64 rmdir_ino = 0;
3196	u64 ancestor;
3197	bool is_orphan;
3198	int ret;
3199
3200	name = fs_path_alloc();
3201	from_path = fs_path_alloc();
3202	if (!name || !from_path) {
3203		ret = -ENOMEM;
3204		goto out;
3205	}
3206
3207	dm = get_waiting_dir_move(sctx, pm->ino);
3208	ASSERT(dm);
3209	rmdir_ino = dm->rmdir_ino;
3210	is_orphan = dm->orphanized;
3211	free_waiting_dir_move(sctx, dm);
3212
3213	if (is_orphan) {
3214		ret = gen_unique_name(sctx, pm->ino,
3215				      pm->gen, from_path);
3216	} else {
3217		ret = get_first_ref(sctx->parent_root, pm->ino,
3218				    &parent_ino, &parent_gen, name);
3219		if (ret < 0)
3220			goto out;
3221		ret = get_cur_path(sctx, parent_ino, parent_gen,
3222				   from_path);
3223		if (ret < 0)
3224			goto out;
3225		ret = fs_path_add_path(from_path, name);
3226	}
3227	if (ret < 0)
3228		goto out;
3229
3230	sctx->send_progress = sctx->cur_ino + 1;
3231	ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor);
3232	if (ret < 0)
3233		goto out;
3234	if (ret) {
3235		LIST_HEAD(deleted_refs);
3236		ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID);
3237		ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor,
3238					   &pm->update_refs, &deleted_refs,
3239					   is_orphan);
3240		if (ret < 0)
3241			goto out;
3242		if (rmdir_ino) {
3243			dm = get_waiting_dir_move(sctx, pm->ino);
3244			ASSERT(dm);
3245			dm->rmdir_ino = rmdir_ino;
3246		}
3247		goto out;
3248	}
3249	fs_path_reset(name);
3250	to_path = name;
3251	name = NULL;
 
 
 
 
 
 
 
 
3252	ret = get_cur_path(sctx, pm->ino, pm->gen, to_path);
3253	if (ret < 0)
3254		goto out;
3255
3256	ret = send_rename(sctx, from_path, to_path);
3257	if (ret < 0)
3258		goto out;
3259
3260	if (rmdir_ino) {
3261		struct orphan_dir_info *odi;
3262
3263		odi = get_orphan_dir_info(sctx, rmdir_ino);
3264		if (!odi) {
3265			/* already deleted */
3266			goto finish;
3267		}
3268		ret = can_rmdir(sctx, rmdir_ino, odi->gen, sctx->cur_ino);
3269		if (ret < 0)
3270			goto out;
3271		if (!ret)
3272			goto finish;
3273
3274		name = fs_path_alloc();
3275		if (!name) {
3276			ret = -ENOMEM;
3277			goto out;
3278		}
3279		ret = get_cur_path(sctx, rmdir_ino, odi->gen, name);
3280		if (ret < 0)
3281			goto out;
3282		ret = send_rmdir(sctx, name);
3283		if (ret < 0)
3284			goto out;
3285		free_orphan_dir_info(sctx, odi);
3286	}
3287
3288finish:
3289	ret = send_utimes(sctx, pm->ino, pm->gen);
3290	if (ret < 0)
3291		goto out;
3292
3293	/*
3294	 * After rename/move, need to update the utimes of both new parent(s)
3295	 * and old parent(s).
3296	 */
3297	list_for_each_entry(cur, &pm->update_refs, list) {
3298		/*
3299		 * The parent inode might have been deleted in the send snapshot
3300		 */
3301		ret = get_inode_info(sctx->send_root, cur->dir, NULL,
3302				     NULL, NULL, NULL, NULL, NULL);
3303		if (ret == -ENOENT) {
3304			ret = 0;
3305			continue;
3306		}
3307		if (ret < 0)
3308			goto out;
3309
3310		ret = send_utimes(sctx, cur->dir, cur->dir_gen);
3311		if (ret < 0)
3312			goto out;
3313	}
3314
3315out:
3316	fs_path_free(name);
3317	fs_path_free(from_path);
3318	fs_path_free(to_path);
3319	sctx->send_progress = orig_progress;
3320
3321	return ret;
3322}
3323
3324static void free_pending_move(struct send_ctx *sctx, struct pending_dir_move *m)
3325{
3326	if (!list_empty(&m->list))
3327		list_del(&m->list);
3328	if (!RB_EMPTY_NODE(&m->node))
3329		rb_erase(&m->node, &sctx->pending_dir_moves);
3330	__free_recorded_refs(&m->update_refs);
3331	kfree(m);
3332}
3333
3334static void tail_append_pending_moves(struct pending_dir_move *moves,
3335				      struct list_head *stack)
3336{
3337	if (list_empty(&moves->list)) {
3338		list_add_tail(&moves->list, stack);
3339	} else {
3340		LIST_HEAD(list);
3341		list_splice_init(&moves->list, &list);
3342		list_add_tail(&moves->list, stack);
3343		list_splice_tail(&list, stack);
3344	}
3345}
3346
3347static int apply_children_dir_moves(struct send_ctx *sctx)
3348{
3349	struct pending_dir_move *pm;
3350	struct list_head stack;
3351	u64 parent_ino = sctx->cur_ino;
3352	int ret = 0;
3353
3354	pm = get_pending_dir_moves(sctx, parent_ino);
3355	if (!pm)
3356		return 0;
3357
3358	INIT_LIST_HEAD(&stack);
3359	tail_append_pending_moves(pm, &stack);
3360
3361	while (!list_empty(&stack)) {
3362		pm = list_first_entry(&stack, struct pending_dir_move, list);
3363		parent_ino = pm->ino;
3364		ret = apply_dir_move(sctx, pm);
3365		free_pending_move(sctx, pm);
3366		if (ret)
3367			goto out;
3368		pm = get_pending_dir_moves(sctx, parent_ino);
3369		if (pm)
3370			tail_append_pending_moves(pm, &stack);
3371	}
3372	return 0;
3373
3374out:
3375	while (!list_empty(&stack)) {
3376		pm = list_first_entry(&stack, struct pending_dir_move, list);
3377		free_pending_move(sctx, pm);
3378	}
3379	return ret;
3380}
3381
3382/*
3383 * We might need to delay a directory rename even when no ancestor directory
3384 * (in the send root) with a higher inode number than ours (sctx->cur_ino) was
3385 * renamed. This happens when we rename a directory to the old name (the name
3386 * in the parent root) of some other unrelated directory that got its rename
3387 * delayed due to some ancestor with higher number that got renamed.
3388 *
3389 * Example:
3390 *
3391 * Parent snapshot:
3392 * .                                       (ino 256)
3393 * |---- a/                                (ino 257)
3394 * |     |---- file                        (ino 260)
3395 * |
3396 * |---- b/                                (ino 258)
3397 * |---- c/                                (ino 259)
3398 *
3399 * Send snapshot:
3400 * .                                       (ino 256)
3401 * |---- a/                                (ino 258)
3402 * |---- x/                                (ino 259)
3403 *       |---- y/                          (ino 257)
3404 *             |----- file                 (ino 260)
3405 *
3406 * Here we can not rename 258 from 'b' to 'a' without the rename of inode 257
3407 * from 'a' to 'x/y' happening first, which in turn depends on the rename of
3408 * inode 259 from 'c' to 'x'. So the order of rename commands the send stream
3409 * must issue is:
3410 *
3411 * 1 - rename 259 from 'c' to 'x'
3412 * 2 - rename 257 from 'a' to 'x/y'
3413 * 3 - rename 258 from 'b' to 'a'
3414 *
3415 * Returns 1 if the rename of sctx->cur_ino needs to be delayed, 0 if it can
3416 * be done right away and < 0 on error.
3417 */
3418static int wait_for_dest_dir_move(struct send_ctx *sctx,
3419				  struct recorded_ref *parent_ref,
3420				  const bool is_orphan)
3421{
3422	struct btrfs_fs_info *fs_info = sctx->parent_root->fs_info;
3423	struct btrfs_path *path;
3424	struct btrfs_key key;
3425	struct btrfs_key di_key;
3426	struct btrfs_dir_item *di;
3427	u64 left_gen;
3428	u64 right_gen;
3429	int ret = 0;
3430	struct waiting_dir_move *wdm;
3431
3432	if (RB_EMPTY_ROOT(&sctx->waiting_dir_moves))
 
 
 
3433		return 0;
3434
3435	path = alloc_path_for_send();
3436	if (!path)
3437		return -ENOMEM;
 
 
 
3438
3439	key.objectid = parent_ref->dir;
3440	key.type = BTRFS_DIR_ITEM_KEY;
3441	key.offset = btrfs_name_hash(parent_ref->name, parent_ref->name_len);
3442
3443	ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0);
3444	if (ret < 0) {
3445		goto out;
3446	} else if (ret > 0) {
3447		ret = 0;
3448		goto out;
3449	}
3450
3451	di = btrfs_match_dir_item_name(fs_info, path, parent_ref->name,
3452				       parent_ref->name_len);
3453	if (!di) {
3454		ret = 0;
3455		goto out;
3456	}
3457	/*
3458	 * di_key.objectid has the number of the inode that has a dentry in the
3459	 * parent directory with the same name that sctx->cur_ino is being
3460	 * renamed to. We need to check if that inode is in the send root as
3461	 * well and if it is currently marked as an inode with a pending rename,
3462	 * if it is, we need to delay the rename of sctx->cur_ino as well, so
3463	 * that it happens after that other inode is renamed.
3464	 */
3465	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &di_key);
3466	if (di_key.type != BTRFS_INODE_ITEM_KEY) {
3467		ret = 0;
3468		goto out;
3469	}
3470
3471	ret = get_inode_info(sctx->parent_root, di_key.objectid, NULL,
3472			     &left_gen, NULL, NULL, NULL, NULL);
3473	if (ret < 0)
3474		goto out;
3475	ret = get_inode_info(sctx->send_root, di_key.objectid, NULL,
3476			     &right_gen, NULL, NULL, NULL, NULL);
3477	if (ret < 0) {
3478		if (ret == -ENOENT)
3479			ret = 0;
3480		goto out;
3481	}
3482
3483	/* Different inode, no need to delay the rename of sctx->cur_ino */
3484	if (right_gen != left_gen) {
 
3485		ret = 0;
3486		goto out;
3487	}
3488
3489	wdm = get_waiting_dir_move(sctx, di_key.objectid);
3490	if (wdm && !wdm->orphanized) {
3491		ret = add_pending_dir_move(sctx,
3492					   sctx->cur_ino,
3493					   sctx->cur_inode_gen,
3494					   di_key.objectid,
3495					   &sctx->new_refs,
3496					   &sctx->deleted_refs,
3497					   is_orphan);
3498		if (!ret)
3499			ret = 1;
3500	}
3501out:
3502	btrfs_free_path(path);
3503	return ret;
3504}
3505
3506/*
3507 * Check if inode ino2, or any of its ancestors, is inode ino1.
3508 * Return 1 if true, 0 if false and < 0 on error.
3509 */
3510static int check_ino_in_path(struct btrfs_root *root,
3511			     const u64 ino1,
3512			     const u64 ino1_gen,
3513			     const u64 ino2,
3514			     const u64 ino2_gen,
3515			     struct fs_path *fs_path)
3516{
3517	u64 ino = ino2;
3518
3519	if (ino1 == ino2)
3520		return ino1_gen == ino2_gen;
3521
3522	while (ino > BTRFS_FIRST_FREE_OBJECTID) {
3523		u64 parent;
3524		u64 parent_gen;
3525		int ret;
3526
3527		fs_path_reset(fs_path);
3528		ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path);
3529		if (ret < 0)
3530			return ret;
3531		if (parent == ino1)
3532			return parent_gen == ino1_gen;
3533		ino = parent;
3534	}
3535	return 0;
3536}
3537
3538/*
3539 * Check if ino ino1 is an ancestor of inode ino2 in the given root for any
3540 * possible path (in case ino2 is not a directory and has multiple hard links).
3541 * Return 1 if true, 0 if false and < 0 on error.
3542 */
3543static int is_ancestor(struct btrfs_root *root,
3544		       const u64 ino1,
3545		       const u64 ino1_gen,
3546		       const u64 ino2,
3547		       struct fs_path *fs_path)
3548{
3549	bool free_fs_path = false;
3550	int ret = 0;
3551	struct btrfs_path *path = NULL;
3552	struct btrfs_key key;
3553
3554	if (!fs_path) {
3555		fs_path = fs_path_alloc();
3556		if (!fs_path)
3557			return -ENOMEM;
3558		free_fs_path = true;
3559	}
3560
3561	path = alloc_path_for_send();
3562	if (!path) {
3563		ret = -ENOMEM;
3564		goto out;
3565	}
3566
3567	key.objectid = ino2;
3568	key.type = BTRFS_INODE_REF_KEY;
3569	key.offset = 0;
3570
3571	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3572	if (ret < 0)
3573		goto out;
3574
3575	while (true) {
3576		struct extent_buffer *leaf = path->nodes[0];
3577		int slot = path->slots[0];
3578		u32 cur_offset = 0;
3579		u32 item_size;
3580
3581		if (slot >= btrfs_header_nritems(leaf)) {
3582			ret = btrfs_next_leaf(root, path);
3583			if (ret < 0)
3584				goto out;
3585			if (ret > 0)
3586				break;
3587			continue;
3588		}
3589
3590		btrfs_item_key_to_cpu(leaf, &key, slot);
3591		if (key.objectid != ino2)
3592			break;
3593		if (key.type != BTRFS_INODE_REF_KEY &&
3594		    key.type != BTRFS_INODE_EXTREF_KEY)
3595			break;
3596
3597		item_size = btrfs_item_size_nr(leaf, slot);
3598		while (cur_offset < item_size) {
3599			u64 parent;
3600			u64 parent_gen;
3601
3602			if (key.type == BTRFS_INODE_EXTREF_KEY) {
3603				unsigned long ptr;
3604				struct btrfs_inode_extref *extref;
3605
3606				ptr = btrfs_item_ptr_offset(leaf, slot);
3607				extref = (struct btrfs_inode_extref *)
3608					(ptr + cur_offset);
3609				parent = btrfs_inode_extref_parent(leaf,
3610								   extref);
3611				cur_offset += sizeof(*extref);
3612				cur_offset += btrfs_inode_extref_name_len(leaf,
3613								  extref);
3614			} else {
3615				parent = key.offset;
3616				cur_offset = item_size;
3617			}
3618
3619			ret = get_inode_info(root, parent, NULL, &parent_gen,
3620					     NULL, NULL, NULL, NULL);
3621			if (ret < 0)
3622				goto out;
3623			ret = check_ino_in_path(root, ino1, ino1_gen,
3624						parent, parent_gen, fs_path);
3625			if (ret)
3626				goto out;
3627		}
3628		path->slots[0]++;
3629	}
3630	ret = 0;
3631 out:
3632	btrfs_free_path(path);
3633	if (free_fs_path)
3634		fs_path_free(fs_path);
3635	return ret;
3636}
3637
3638static int wait_for_parent_move(struct send_ctx *sctx,
3639				struct recorded_ref *parent_ref,
3640				const bool is_orphan)
3641{
3642	int ret = 0;
3643	u64 ino = parent_ref->dir;
3644	u64 ino_gen = parent_ref->dir_gen;
3645	u64 parent_ino_before, parent_ino_after;
3646	struct fs_path *path_before = NULL;
3647	struct fs_path *path_after = NULL;
3648	int len1, len2;
3649
3650	path_after = fs_path_alloc();
3651	path_before = fs_path_alloc();
3652	if (!path_after || !path_before) {
3653		ret = -ENOMEM;
3654		goto out;
3655	}
3656
3657	/*
3658	 * Our current directory inode may not yet be renamed/moved because some
3659	 * ancestor (immediate or not) has to be renamed/moved first. So find if
3660	 * such ancestor exists and make sure our own rename/move happens after
3661	 * that ancestor is processed to avoid path build infinite loops (done
3662	 * at get_cur_path()).
 
3663	 */
3664	while (ino > BTRFS_FIRST_FREE_OBJECTID) {
3665		u64 parent_ino_after_gen;
3666
3667		if (is_waiting_for_move(sctx, ino)) {
3668			/*
3669			 * If the current inode is an ancestor of ino in the
3670			 * parent root, we need to delay the rename of the
3671			 * current inode, otherwise don't delayed the rename
3672			 * because we can end up with a circular dependency
3673			 * of renames, resulting in some directories never
3674			 * getting the respective rename operations issued in
3675			 * the send stream or getting into infinite path build
3676			 * loops.
3677			 */
3678			ret = is_ancestor(sctx->parent_root,
3679					  sctx->cur_ino, sctx->cur_inode_gen,
3680					  ino, path_before);
3681			if (ret)
3682				break;
3683		}
3684
3685		fs_path_reset(path_before);
3686		fs_path_reset(path_after);
3687
3688		ret = get_first_ref(sctx->send_root, ino, &parent_ino_after,
3689				    &parent_ino_after_gen, path_after);
3690		if (ret < 0)
3691			goto out;
3692		ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before,
3693				    NULL, path_before);
3694		if (ret < 0 && ret != -ENOENT) {
3695			goto out;
3696		} else if (ret == -ENOENT) {
3697			ret = 0;
3698			break;
 
 
3699		}
3700
3701		len1 = fs_path_len(path_before);
3702		len2 = fs_path_len(path_after);
3703		if (ino > sctx->cur_ino &&
3704		    (parent_ino_before != parent_ino_after || len1 != len2 ||
3705		     memcmp(path_before->start, path_after->start, len1))) {
3706			u64 parent_ino_gen;
3707
3708			ret = get_inode_info(sctx->parent_root, ino, NULL,
3709					     &parent_ino_gen, NULL, NULL, NULL,
3710					     NULL);
3711			if (ret < 0)
3712				goto out;
3713			if (ino_gen == parent_ino_gen) {
3714				ret = 1;
3715				break;
 
 
 
 
 
3716			}
 
 
 
 
 
3717		}
 
3718		ino = parent_ino_after;
3719		ino_gen = parent_ino_after_gen;
3720	}
3721
3722out:
3723	fs_path_free(path_before);
3724	fs_path_free(path_after);
3725
3726	if (ret == 1) {
3727		ret = add_pending_dir_move(sctx,
3728					   sctx->cur_ino,
3729					   sctx->cur_inode_gen,
3730					   ino,
3731					   &sctx->new_refs,
3732					   &sctx->deleted_refs,
3733					   is_orphan);
3734		if (!ret)
3735			ret = 1;
3736	}
3737
3738	return ret;
3739}
3740
3741static int update_ref_path(struct send_ctx *sctx, struct recorded_ref *ref)
3742{
3743	int ret;
3744	struct fs_path *new_path;
3745
3746	/*
3747	 * Our reference's name member points to its full_path member string, so
3748	 * we use here a new path.
3749	 */
3750	new_path = fs_path_alloc();
3751	if (!new_path)
3752		return -ENOMEM;
3753
3754	ret = get_cur_path(sctx, ref->dir, ref->dir_gen, new_path);
3755	if (ret < 0) {
3756		fs_path_free(new_path);
3757		return ret;
3758	}
3759	ret = fs_path_add(new_path, ref->name, ref->name_len);
3760	if (ret < 0) {
3761		fs_path_free(new_path);
3762		return ret;
3763	}
3764
3765	fs_path_free(ref->full_path);
3766	set_ref_path(ref, new_path);
3767
3768	return 0;
3769}
3770
3771/*
3772 * This does all the move/link/unlink/rmdir magic.
3773 */
3774static int process_recorded_refs(struct send_ctx *sctx, int *pending_move)
3775{
3776	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
3777	int ret = 0;
3778	struct recorded_ref *cur;
3779	struct recorded_ref *cur2;
3780	struct list_head check_dirs;
3781	struct fs_path *valid_path = NULL;
3782	u64 ow_inode = 0;
3783	u64 ow_gen;
3784	u64 ow_mode;
3785	int did_overwrite = 0;
3786	int is_orphan = 0;
3787	u64 last_dir_ino_rm = 0;
3788	bool can_rename = true;
3789	bool orphanized_dir = false;
3790	bool orphanized_ancestor = false;
3791
3792	btrfs_debug(fs_info, "process_recorded_refs %llu", sctx->cur_ino);
3793
3794	/*
3795	 * This should never happen as the root dir always has the same ref
3796	 * which is always '..'
3797	 */
3798	BUG_ON(sctx->cur_ino <= BTRFS_FIRST_FREE_OBJECTID);
3799	INIT_LIST_HEAD(&check_dirs);
3800
3801	valid_path = fs_path_alloc();
3802	if (!valid_path) {
3803		ret = -ENOMEM;
3804		goto out;
3805	}
3806
3807	/*
3808	 * First, check if the first ref of the current inode was overwritten
3809	 * before. If yes, we know that the current inode was already orphanized
3810	 * and thus use the orphan name. If not, we can use get_cur_path to
3811	 * get the path of the first ref as it would like while receiving at
3812	 * this point in time.
3813	 * New inodes are always orphan at the beginning, so force to use the
3814	 * orphan name in this case.
3815	 * The first ref is stored in valid_path and will be updated if it
3816	 * gets moved around.
3817	 */
3818	if (!sctx->cur_inode_new) {
3819		ret = did_overwrite_first_ref(sctx, sctx->cur_ino,
3820				sctx->cur_inode_gen);
3821		if (ret < 0)
3822			goto out;
3823		if (ret)
3824			did_overwrite = 1;
3825	}
3826	if (sctx->cur_inode_new || did_overwrite) {
3827		ret = gen_unique_name(sctx, sctx->cur_ino,
3828				sctx->cur_inode_gen, valid_path);
3829		if (ret < 0)
3830			goto out;
3831		is_orphan = 1;
3832	} else {
3833		ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen,
3834				valid_path);
3835		if (ret < 0)
3836			goto out;
3837	}
3838
3839	list_for_each_entry(cur, &sctx->new_refs, list) {
3840		/*
3841		 * We may have refs where the parent directory does not exist
3842		 * yet. This happens if the parent directories inum is higher
3843		 * the the current inum. To handle this case, we create the
3844		 * parent directory out of order. But we need to check if this
3845		 * did already happen before due to other refs in the same dir.
3846		 */
3847		ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
3848		if (ret < 0)
3849			goto out;
3850		if (ret == inode_state_will_create) {
3851			ret = 0;
3852			/*
3853			 * First check if any of the current inodes refs did
3854			 * already create the dir.
3855			 */
3856			list_for_each_entry(cur2, &sctx->new_refs, list) {
3857				if (cur == cur2)
3858					break;
3859				if (cur2->dir == cur->dir) {
3860					ret = 1;
3861					break;
3862				}
3863			}
3864
3865			/*
3866			 * If that did not happen, check if a previous inode
3867			 * did already create the dir.
3868			 */
3869			if (!ret)
3870				ret = did_create_dir(sctx, cur->dir);
3871			if (ret < 0)
3872				goto out;
3873			if (!ret) {
3874				ret = send_create_inode(sctx, cur->dir);
3875				if (ret < 0)
3876					goto out;
3877			}
3878		}
3879
3880		/*
3881		 * Check if this new ref would overwrite the first ref of
3882		 * another unprocessed inode. If yes, orphanize the
3883		 * overwritten inode. If we find an overwritten ref that is
3884		 * not the first ref, simply unlink it.
3885		 */
3886		ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen,
3887				cur->name, cur->name_len,
3888				&ow_inode, &ow_gen, &ow_mode);
3889		if (ret < 0)
3890			goto out;
3891		if (ret) {
3892			ret = is_first_ref(sctx->parent_root,
3893					   ow_inode, cur->dir, cur->name,
3894					   cur->name_len);
3895			if (ret < 0)
3896				goto out;
3897			if (ret) {
3898				struct name_cache_entry *nce;
3899				struct waiting_dir_move *wdm;
3900
3901				ret = orphanize_inode(sctx, ow_inode, ow_gen,
3902						cur->full_path);
3903				if (ret < 0)
3904					goto out;
3905				if (S_ISDIR(ow_mode))
3906					orphanized_dir = true;
3907
3908				/*
3909				 * If ow_inode has its rename operation delayed
3910				 * make sure that its orphanized name is used in
3911				 * the source path when performing its rename
3912				 * operation.
3913				 */
3914				if (is_waiting_for_move(sctx, ow_inode)) {
3915					wdm = get_waiting_dir_move(sctx,
3916								   ow_inode);
3917					ASSERT(wdm);
3918					wdm->orphanized = true;
3919				}
3920
3921				/*
3922				 * Make sure we clear our orphanized inode's
3923				 * name from the name cache. This is because the
3924				 * inode ow_inode might be an ancestor of some
3925				 * other inode that will be orphanized as well
3926				 * later and has an inode number greater than
3927				 * sctx->send_progress. We need to prevent
3928				 * future name lookups from using the old name
3929				 * and get instead the orphan name.
3930				 */
3931				nce = name_cache_search(sctx, ow_inode, ow_gen);
3932				if (nce) {
3933					name_cache_delete(sctx, nce);
3934					kfree(nce);
3935				}
3936
3937				/*
3938				 * ow_inode might currently be an ancestor of
3939				 * cur_ino, therefore compute valid_path (the
3940				 * current path of cur_ino) again because it
3941				 * might contain the pre-orphanization name of
3942				 * ow_inode, which is no longer valid.
3943				 */
3944				ret = is_ancestor(sctx->parent_root,
3945						  ow_inode, ow_gen,
3946						  sctx->cur_ino, NULL);
3947				if (ret > 0) {
3948					orphanized_ancestor = true;
3949					fs_path_reset(valid_path);
3950					ret = get_cur_path(sctx, sctx->cur_ino,
3951							   sctx->cur_inode_gen,
3952							   valid_path);
3953				}
3954				if (ret < 0)
3955					goto out;
3956			} else {
3957				ret = send_unlink(sctx, cur->full_path);
3958				if (ret < 0)
3959					goto out;
3960			}
3961		}
3962
3963		if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root) {
3964			ret = wait_for_dest_dir_move(sctx, cur, is_orphan);
3965			if (ret < 0)
3966				goto out;
3967			if (ret == 1) {
3968				can_rename = false;
3969				*pending_move = 1;
3970			}
3971		}
3972
3973		if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root &&
3974		    can_rename) {
3975			ret = wait_for_parent_move(sctx, cur, is_orphan);
3976			if (ret < 0)
3977				goto out;
3978			if (ret == 1) {
3979				can_rename = false;
3980				*pending_move = 1;
3981			}
3982		}
3983
3984		/*
3985		 * link/move the ref to the new place. If we have an orphan
3986		 * inode, move it and update valid_path. If not, link or move
3987		 * it depending on the inode mode.
3988		 */
3989		if (is_orphan && can_rename) {
3990			ret = send_rename(sctx, valid_path, cur->full_path);
3991			if (ret < 0)
3992				goto out;
3993			is_orphan = 0;
3994			ret = fs_path_copy(valid_path, cur->full_path);
3995			if (ret < 0)
3996				goto out;
3997		} else if (can_rename) {
3998			if (S_ISDIR(sctx->cur_inode_mode)) {
3999				/*
4000				 * Dirs can't be linked, so move it. For moved
4001				 * dirs, we always have one new and one deleted
4002				 * ref. The deleted ref is ignored later.
4003				 */
4004				ret = send_rename(sctx, valid_path,
4005						  cur->full_path);
4006				if (!ret)
4007					ret = fs_path_copy(valid_path,
4008							   cur->full_path);
4009				if (ret < 0)
4010					goto out;
4011			} else {
4012				/*
4013				 * We might have previously orphanized an inode
4014				 * which is an ancestor of our current inode,
4015				 * so our reference's full path, which was
4016				 * computed before any such orphanizations, must
4017				 * be updated.
4018				 */
4019				if (orphanized_dir) {
4020					ret = update_ref_path(sctx, cur);
4021					if (ret < 0)
4022						goto out;
4023				}
 
 
 
4024				ret = send_link(sctx, cur->full_path,
4025						valid_path);
4026				if (ret < 0)
4027					goto out;
4028			}
4029		}
4030		ret = dup_ref(cur, &check_dirs);
4031		if (ret < 0)
4032			goto out;
4033	}
4034
4035	if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) {
4036		/*
4037		 * Check if we can already rmdir the directory. If not,
4038		 * orphanize it. For every dir item inside that gets deleted
4039		 * later, we do this check again and rmdir it then if possible.
4040		 * See the use of check_dirs for more details.
4041		 */
4042		ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_inode_gen,
4043				sctx->cur_ino);
4044		if (ret < 0)
4045			goto out;
4046		if (ret) {
4047			ret = send_rmdir(sctx, valid_path);
4048			if (ret < 0)
4049				goto out;
4050		} else if (!is_orphan) {
4051			ret = orphanize_inode(sctx, sctx->cur_ino,
4052					sctx->cur_inode_gen, valid_path);
4053			if (ret < 0)
4054				goto out;
4055			is_orphan = 1;
4056		}
4057
4058		list_for_each_entry(cur, &sctx->deleted_refs, list) {
4059			ret = dup_ref(cur, &check_dirs);
4060			if (ret < 0)
4061				goto out;
4062		}
4063	} else if (S_ISDIR(sctx->cur_inode_mode) &&
4064		   !list_empty(&sctx->deleted_refs)) {
4065		/*
4066		 * We have a moved dir. Add the old parent to check_dirs
4067		 */
4068		cur = list_entry(sctx->deleted_refs.next, struct recorded_ref,
4069				list);
4070		ret = dup_ref(cur, &check_dirs);
4071		if (ret < 0)
4072			goto out;
4073	} else if (!S_ISDIR(sctx->cur_inode_mode)) {
4074		/*
4075		 * We have a non dir inode. Go through all deleted refs and
4076		 * unlink them if they were not already overwritten by other
4077		 * inodes.
4078		 */
4079		list_for_each_entry(cur, &sctx->deleted_refs, list) {
4080			ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen,
4081					sctx->cur_ino, sctx->cur_inode_gen,
4082					cur->name, cur->name_len);
4083			if (ret < 0)
4084				goto out;
4085			if (!ret) {
4086				/*
4087				 * If we orphanized any ancestor before, we need
4088				 * to recompute the full path for deleted names,
4089				 * since any such path was computed before we
4090				 * processed any references and orphanized any
4091				 * ancestor inode.
4092				 */
4093				if (orphanized_ancestor) {
4094					ret = update_ref_path(sctx, cur);
4095					if (ret < 0)
4096						goto out;
4097				}
4098				ret = send_unlink(sctx, cur->full_path);
4099				if (ret < 0)
4100					goto out;
4101			}
4102			ret = dup_ref(cur, &check_dirs);
4103			if (ret < 0)
4104				goto out;
4105		}
4106		/*
4107		 * If the inode is still orphan, unlink the orphan. This may
4108		 * happen when a previous inode did overwrite the first ref
4109		 * of this inode and no new refs were added for the current
4110		 * inode. Unlinking does not mean that the inode is deleted in
4111		 * all cases. There may still be links to this inode in other
4112		 * places.
4113		 */
4114		if (is_orphan) {
4115			ret = send_unlink(sctx, valid_path);
4116			if (ret < 0)
4117				goto out;
4118		}
4119	}
4120
4121	/*
4122	 * We did collect all parent dirs where cur_inode was once located. We
4123	 * now go through all these dirs and check if they are pending for
4124	 * deletion and if it's finally possible to perform the rmdir now.
4125	 * We also update the inode stats of the parent dirs here.
4126	 */
4127	list_for_each_entry(cur, &check_dirs, list) {
4128		/*
4129		 * In case we had refs into dirs that were not processed yet,
4130		 * we don't need to do the utime and rmdir logic for these dirs.
4131		 * The dir will be processed later.
4132		 */
4133		if (cur->dir > sctx->cur_ino)
4134			continue;
4135
4136		ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
4137		if (ret < 0)
4138			goto out;
4139
4140		if (ret == inode_state_did_create ||
4141		    ret == inode_state_no_change) {
4142			/* TODO delayed utimes */
4143			ret = send_utimes(sctx, cur->dir, cur->dir_gen);
4144			if (ret < 0)
4145				goto out;
4146		} else if (ret == inode_state_did_delete &&
4147			   cur->dir != last_dir_ino_rm) {
4148			ret = can_rmdir(sctx, cur->dir, cur->dir_gen,
4149					sctx->cur_ino);
4150			if (ret < 0)
4151				goto out;
4152			if (ret) {
4153				ret = get_cur_path(sctx, cur->dir,
4154						   cur->dir_gen, valid_path);
4155				if (ret < 0)
4156					goto out;
4157				ret = send_rmdir(sctx, valid_path);
4158				if (ret < 0)
4159					goto out;
4160				last_dir_ino_rm = cur->dir;
4161			}
4162		}
4163	}
4164
4165	ret = 0;
4166
4167out:
4168	__free_recorded_refs(&check_dirs);
4169	free_recorded_refs(sctx);
4170	fs_path_free(valid_path);
4171	return ret;
4172}
4173
4174static int record_ref(struct btrfs_root *root, u64 dir, struct fs_path *name,
4175		      void *ctx, struct list_head *refs)
4176{
4177	int ret = 0;
4178	struct send_ctx *sctx = ctx;
4179	struct fs_path *p;
4180	u64 gen;
4181
4182	p = fs_path_alloc();
4183	if (!p)
4184		return -ENOMEM;
4185
4186	ret = get_inode_info(root, dir, NULL, &gen, NULL, NULL,
4187			NULL, NULL);
4188	if (ret < 0)
4189		goto out;
4190
4191	ret = get_cur_path(sctx, dir, gen, p);
4192	if (ret < 0)
4193		goto out;
4194	ret = fs_path_add_path(p, name);
4195	if (ret < 0)
4196		goto out;
4197
4198	ret = __record_ref(refs, dir, gen, p);
4199
4200out:
4201	if (ret)
4202		fs_path_free(p);
4203	return ret;
4204}
4205
4206static int __record_new_ref(int num, u64 dir, int index,
4207			    struct fs_path *name,
4208			    void *ctx)
4209{
4210	struct send_ctx *sctx = ctx;
4211	return record_ref(sctx->send_root, dir, name, ctx, &sctx->new_refs);
 
4212}
4213
4214
4215static int __record_deleted_ref(int num, u64 dir, int index,
4216				struct fs_path *name,
4217				void *ctx)
4218{
4219	struct send_ctx *sctx = ctx;
4220	return record_ref(sctx->parent_root, dir, name, ctx,
4221			  &sctx->deleted_refs);
4222}
4223
4224static int record_new_ref(struct send_ctx *sctx)
4225{
4226	int ret;
4227
4228	ret = iterate_inode_ref(sctx->send_root, sctx->left_path,
4229				sctx->cmp_key, 0, __record_new_ref, sctx);
4230	if (ret < 0)
4231		goto out;
4232	ret = 0;
4233
4234out:
4235	return ret;
4236}
4237
4238static int record_deleted_ref(struct send_ctx *sctx)
4239{
4240	int ret;
4241
4242	ret = iterate_inode_ref(sctx->parent_root, sctx->right_path,
4243				sctx->cmp_key, 0, __record_deleted_ref, sctx);
4244	if (ret < 0)
4245		goto out;
4246	ret = 0;
4247
4248out:
4249	return ret;
4250}
4251
4252struct find_ref_ctx {
4253	u64 dir;
4254	u64 dir_gen;
4255	struct btrfs_root *root;
4256	struct fs_path *name;
4257	int found_idx;
4258};
4259
4260static int __find_iref(int num, u64 dir, int index,
4261		       struct fs_path *name,
4262		       void *ctx_)
4263{
4264	struct find_ref_ctx *ctx = ctx_;
4265	u64 dir_gen;
4266	int ret;
4267
4268	if (dir == ctx->dir && fs_path_len(name) == fs_path_len(ctx->name) &&
4269	    strncmp(name->start, ctx->name->start, fs_path_len(name)) == 0) {
4270		/*
4271		 * To avoid doing extra lookups we'll only do this if everything
4272		 * else matches.
4273		 */
4274		ret = get_inode_info(ctx->root, dir, NULL, &dir_gen, NULL,
4275				     NULL, NULL, NULL);
4276		if (ret)
4277			return ret;
4278		if (dir_gen != ctx->dir_gen)
4279			return 0;
4280		ctx->found_idx = num;
4281		return 1;
4282	}
4283	return 0;
4284}
4285
4286static int find_iref(struct btrfs_root *root,
4287		     struct btrfs_path *path,
4288		     struct btrfs_key *key,
4289		     u64 dir, u64 dir_gen, struct fs_path *name)
4290{
4291	int ret;
4292	struct find_ref_ctx ctx;
4293
4294	ctx.dir = dir;
4295	ctx.name = name;
4296	ctx.dir_gen = dir_gen;
4297	ctx.found_idx = -1;
4298	ctx.root = root;
4299
4300	ret = iterate_inode_ref(root, path, key, 0, __find_iref, &ctx);
4301	if (ret < 0)
4302		return ret;
4303
4304	if (ctx.found_idx == -1)
4305		return -ENOENT;
4306
4307	return ctx.found_idx;
4308}
4309
4310static int __record_changed_new_ref(int num, u64 dir, int index,
4311				    struct fs_path *name,
4312				    void *ctx)
4313{
4314	u64 dir_gen;
4315	int ret;
4316	struct send_ctx *sctx = ctx;
4317
4318	ret = get_inode_info(sctx->send_root, dir, NULL, &dir_gen, NULL,
4319			     NULL, NULL, NULL);
4320	if (ret)
4321		return ret;
4322
4323	ret = find_iref(sctx->parent_root, sctx->right_path,
4324			sctx->cmp_key, dir, dir_gen, name);
4325	if (ret == -ENOENT)
4326		ret = __record_new_ref(num, dir, index, name, sctx);
4327	else if (ret > 0)
4328		ret = 0;
4329
4330	return ret;
4331}
4332
4333static int __record_changed_deleted_ref(int num, u64 dir, int index,
4334					struct fs_path *name,
4335					void *ctx)
4336{
4337	u64 dir_gen;
4338	int ret;
4339	struct send_ctx *sctx = ctx;
4340
4341	ret = get_inode_info(sctx->parent_root, dir, NULL, &dir_gen, NULL,
4342			     NULL, NULL, NULL);
4343	if (ret)
4344		return ret;
4345
4346	ret = find_iref(sctx->send_root, sctx->left_path, sctx->cmp_key,
4347			dir, dir_gen, name);
4348	if (ret == -ENOENT)
4349		ret = __record_deleted_ref(num, dir, index, name, sctx);
4350	else if (ret > 0)
4351		ret = 0;
4352
4353	return ret;
4354}
4355
4356static int record_changed_ref(struct send_ctx *sctx)
4357{
4358	int ret = 0;
4359
4360	ret = iterate_inode_ref(sctx->send_root, sctx->left_path,
4361			sctx->cmp_key, 0, __record_changed_new_ref, sctx);
4362	if (ret < 0)
4363		goto out;
4364	ret = iterate_inode_ref(sctx->parent_root, sctx->right_path,
4365			sctx->cmp_key, 0, __record_changed_deleted_ref, sctx);
4366	if (ret < 0)
4367		goto out;
4368	ret = 0;
4369
4370out:
4371	return ret;
4372}
4373
4374/*
4375 * Record and process all refs at once. Needed when an inode changes the
4376 * generation number, which means that it was deleted and recreated.
4377 */
4378static int process_all_refs(struct send_ctx *sctx,
4379			    enum btrfs_compare_tree_result cmd)
4380{
4381	int ret;
4382	struct btrfs_root *root;
4383	struct btrfs_path *path;
4384	struct btrfs_key key;
4385	struct btrfs_key found_key;
4386	struct extent_buffer *eb;
4387	int slot;
4388	iterate_inode_ref_t cb;
4389	int pending_move = 0;
4390
4391	path = alloc_path_for_send();
4392	if (!path)
4393		return -ENOMEM;
4394
4395	if (cmd == BTRFS_COMPARE_TREE_NEW) {
4396		root = sctx->send_root;
4397		cb = __record_new_ref;
4398	} else if (cmd == BTRFS_COMPARE_TREE_DELETED) {
4399		root = sctx->parent_root;
4400		cb = __record_deleted_ref;
4401	} else {
4402		btrfs_err(sctx->send_root->fs_info,
4403				"Wrong command %d in process_all_refs", cmd);
4404		ret = -EINVAL;
4405		goto out;
4406	}
4407
4408	key.objectid = sctx->cmp_key->objectid;
4409	key.type = BTRFS_INODE_REF_KEY;
4410	key.offset = 0;
4411	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4412	if (ret < 0)
4413		goto out;
4414
4415	while (1) {
4416		eb = path->nodes[0];
4417		slot = path->slots[0];
4418		if (slot >= btrfs_header_nritems(eb)) {
4419			ret = btrfs_next_leaf(root, path);
4420			if (ret < 0)
4421				goto out;
4422			else if (ret > 0)
4423				break;
4424			continue;
4425		}
4426
4427		btrfs_item_key_to_cpu(eb, &found_key, slot);
4428
4429		if (found_key.objectid != key.objectid ||
4430		    (found_key.type != BTRFS_INODE_REF_KEY &&
4431		     found_key.type != BTRFS_INODE_EXTREF_KEY))
4432			break;
4433
4434		ret = iterate_inode_ref(root, path, &found_key, 0, cb, sctx);
4435		if (ret < 0)
4436			goto out;
4437
4438		path->slots[0]++;
4439	}
4440	btrfs_release_path(path);
4441
4442	/*
4443	 * We don't actually care about pending_move as we are simply
4444	 * re-creating this inode and will be rename'ing it into place once we
4445	 * rename the parent directory.
4446	 */
4447	ret = process_recorded_refs(sctx, &pending_move);
 
 
 
4448out:
4449	btrfs_free_path(path);
4450	return ret;
4451}
4452
4453static int send_set_xattr(struct send_ctx *sctx,
4454			  struct fs_path *path,
4455			  const char *name, int name_len,
4456			  const char *data, int data_len)
4457{
4458	int ret = 0;
4459
4460	ret = begin_cmd(sctx, BTRFS_SEND_C_SET_XATTR);
4461	if (ret < 0)
4462		goto out;
4463
4464	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
4465	TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
4466	TLV_PUT(sctx, BTRFS_SEND_A_XATTR_DATA, data, data_len);
4467
4468	ret = send_cmd(sctx);
4469
4470tlv_put_failure:
4471out:
4472	return ret;
4473}
4474
4475static int send_remove_xattr(struct send_ctx *sctx,
4476			  struct fs_path *path,
4477			  const char *name, int name_len)
4478{
4479	int ret = 0;
4480
4481	ret = begin_cmd(sctx, BTRFS_SEND_C_REMOVE_XATTR);
4482	if (ret < 0)
4483		goto out;
4484
4485	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
4486	TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
4487
4488	ret = send_cmd(sctx);
4489
4490tlv_put_failure:
4491out:
4492	return ret;
4493}
4494
4495static int __process_new_xattr(int num, struct btrfs_key *di_key,
4496			       const char *name, int name_len,
4497			       const char *data, int data_len,
4498			       u8 type, void *ctx)
4499{
4500	int ret;
4501	struct send_ctx *sctx = ctx;
4502	struct fs_path *p;
4503	struct posix_acl_xattr_header dummy_acl;
4504
4505	p = fs_path_alloc();
4506	if (!p)
4507		return -ENOMEM;
4508
4509	/*
4510	 * This hack is needed because empty acls are stored as zero byte
4511	 * data in xattrs. Problem with that is, that receiving these zero byte
4512	 * acls will fail later. To fix this, we send a dummy acl list that
4513	 * only contains the version number and no entries.
4514	 */
4515	if (!strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS, name_len) ||
4516	    !strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT, name_len)) {
4517		if (data_len == 0) {
4518			dummy_acl.a_version =
4519					cpu_to_le32(POSIX_ACL_XATTR_VERSION);
4520			data = (char *)&dummy_acl;
4521			data_len = sizeof(dummy_acl);
4522		}
4523	}
4524
4525	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
4526	if (ret < 0)
4527		goto out;
4528
4529	ret = send_set_xattr(sctx, p, name, name_len, data, data_len);
4530
4531out:
4532	fs_path_free(p);
4533	return ret;
4534}
4535
4536static int __process_deleted_xattr(int num, struct btrfs_key *di_key,
4537				   const char *name, int name_len,
4538				   const char *data, int data_len,
4539				   u8 type, void *ctx)
4540{
4541	int ret;
4542	struct send_ctx *sctx = ctx;
4543	struct fs_path *p;
4544
4545	p = fs_path_alloc();
4546	if (!p)
4547		return -ENOMEM;
4548
4549	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
4550	if (ret < 0)
4551		goto out;
4552
4553	ret = send_remove_xattr(sctx, p, name, name_len);
4554
4555out:
4556	fs_path_free(p);
4557	return ret;
4558}
4559
4560static int process_new_xattr(struct send_ctx *sctx)
4561{
4562	int ret = 0;
4563
4564	ret = iterate_dir_item(sctx->send_root, sctx->left_path,
4565			       __process_new_xattr, sctx);
4566
4567	return ret;
4568}
4569
4570static int process_deleted_xattr(struct send_ctx *sctx)
4571{
4572	return iterate_dir_item(sctx->parent_root, sctx->right_path,
4573				__process_deleted_xattr, sctx);
 
 
 
 
4574}
4575
4576struct find_xattr_ctx {
4577	const char *name;
4578	int name_len;
4579	int found_idx;
4580	char *found_data;
4581	int found_data_len;
4582};
4583
4584static int __find_xattr(int num, struct btrfs_key *di_key,
4585			const char *name, int name_len,
4586			const char *data, int data_len,
4587			u8 type, void *vctx)
4588{
4589	struct find_xattr_ctx *ctx = vctx;
4590
4591	if (name_len == ctx->name_len &&
4592	    strncmp(name, ctx->name, name_len) == 0) {
4593		ctx->found_idx = num;
4594		ctx->found_data_len = data_len;
4595		ctx->found_data = kmemdup(data, data_len, GFP_KERNEL);
4596		if (!ctx->found_data)
4597			return -ENOMEM;
4598		return 1;
4599	}
4600	return 0;
4601}
4602
4603static int find_xattr(struct btrfs_root *root,
4604		      struct btrfs_path *path,
4605		      struct btrfs_key *key,
4606		      const char *name, int name_len,
4607		      char **data, int *data_len)
4608{
4609	int ret;
4610	struct find_xattr_ctx ctx;
4611
4612	ctx.name = name;
4613	ctx.name_len = name_len;
4614	ctx.found_idx = -1;
4615	ctx.found_data = NULL;
4616	ctx.found_data_len = 0;
4617
4618	ret = iterate_dir_item(root, path, __find_xattr, &ctx);
4619	if (ret < 0)
4620		return ret;
4621
4622	if (ctx.found_idx == -1)
4623		return -ENOENT;
4624	if (data) {
4625		*data = ctx.found_data;
4626		*data_len = ctx.found_data_len;
4627	} else {
4628		kfree(ctx.found_data);
4629	}
4630	return ctx.found_idx;
4631}
4632
4633
4634static int __process_changed_new_xattr(int num, struct btrfs_key *di_key,
4635				       const char *name, int name_len,
4636				       const char *data, int data_len,
4637				       u8 type, void *ctx)
4638{
4639	int ret;
4640	struct send_ctx *sctx = ctx;
4641	char *found_data = NULL;
4642	int found_data_len  = 0;
4643
4644	ret = find_xattr(sctx->parent_root, sctx->right_path,
4645			 sctx->cmp_key, name, name_len, &found_data,
4646			 &found_data_len);
4647	if (ret == -ENOENT) {
4648		ret = __process_new_xattr(num, di_key, name, name_len, data,
4649				data_len, type, ctx);
4650	} else if (ret >= 0) {
4651		if (data_len != found_data_len ||
4652		    memcmp(data, found_data, data_len)) {
4653			ret = __process_new_xattr(num, di_key, name, name_len,
4654					data, data_len, type, ctx);
4655		} else {
4656			ret = 0;
4657		}
4658	}
4659
4660	kfree(found_data);
4661	return ret;
4662}
4663
4664static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key,
4665					   const char *name, int name_len,
4666					   const char *data, int data_len,
4667					   u8 type, void *ctx)
4668{
4669	int ret;
4670	struct send_ctx *sctx = ctx;
4671
4672	ret = find_xattr(sctx->send_root, sctx->left_path, sctx->cmp_key,
4673			 name, name_len, NULL, NULL);
4674	if (ret == -ENOENT)
4675		ret = __process_deleted_xattr(num, di_key, name, name_len, data,
4676				data_len, type, ctx);
4677	else if (ret >= 0)
4678		ret = 0;
4679
4680	return ret;
4681}
4682
4683static int process_changed_xattr(struct send_ctx *sctx)
4684{
4685	int ret = 0;
4686
4687	ret = iterate_dir_item(sctx->send_root, sctx->left_path,
4688			__process_changed_new_xattr, sctx);
4689	if (ret < 0)
4690		goto out;
4691	ret = iterate_dir_item(sctx->parent_root, sctx->right_path,
4692			__process_changed_deleted_xattr, sctx);
4693
4694out:
4695	return ret;
4696}
4697
4698static int process_all_new_xattrs(struct send_ctx *sctx)
4699{
4700	int ret;
4701	struct btrfs_root *root;
4702	struct btrfs_path *path;
4703	struct btrfs_key key;
4704	struct btrfs_key found_key;
4705	struct extent_buffer *eb;
4706	int slot;
4707
4708	path = alloc_path_for_send();
4709	if (!path)
4710		return -ENOMEM;
4711
4712	root = sctx->send_root;
4713
4714	key.objectid = sctx->cmp_key->objectid;
4715	key.type = BTRFS_XATTR_ITEM_KEY;
4716	key.offset = 0;
4717	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4718	if (ret < 0)
4719		goto out;
4720
4721	while (1) {
4722		eb = path->nodes[0];
4723		slot = path->slots[0];
4724		if (slot >= btrfs_header_nritems(eb)) {
4725			ret = btrfs_next_leaf(root, path);
4726			if (ret < 0) {
4727				goto out;
4728			} else if (ret > 0) {
4729				ret = 0;
4730				break;
4731			}
4732			continue;
4733		}
4734
4735		btrfs_item_key_to_cpu(eb, &found_key, slot);
4736		if (found_key.objectid != key.objectid ||
4737		    found_key.type != key.type) {
4738			ret = 0;
4739			goto out;
4740		}
4741
4742		ret = iterate_dir_item(root, path, __process_new_xattr, sctx);
 
4743		if (ret < 0)
4744			goto out;
4745
4746		path->slots[0]++;
4747	}
4748
4749out:
4750	btrfs_free_path(path);
4751	return ret;
4752}
4753
4754static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
4755{
4756	struct btrfs_root *root = sctx->send_root;
4757	struct btrfs_fs_info *fs_info = root->fs_info;
4758	struct inode *inode;
4759	struct page *page;
4760	char *addr;
4761	struct btrfs_key key;
4762	pgoff_t index = offset >> PAGE_SHIFT;
4763	pgoff_t last_index;
4764	unsigned pg_offset = offset & ~PAGE_MASK;
4765	ssize_t ret = 0;
4766
4767	key.objectid = sctx->cur_ino;
4768	key.type = BTRFS_INODE_ITEM_KEY;
4769	key.offset = 0;
4770
4771	inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4772	if (IS_ERR(inode))
4773		return PTR_ERR(inode);
4774
4775	if (offset + len > i_size_read(inode)) {
4776		if (offset > i_size_read(inode))
4777			len = 0;
4778		else
4779			len = offset - i_size_read(inode);
4780	}
4781	if (len == 0)
4782		goto out;
4783
4784	last_index = (offset + len - 1) >> PAGE_SHIFT;
4785
4786	/* initial readahead */
4787	memset(&sctx->ra, 0, sizeof(struct file_ra_state));
4788	file_ra_state_init(&sctx->ra, inode->i_mapping);
 
 
4789
4790	while (index <= last_index) {
4791		unsigned cur_len = min_t(unsigned, len,
4792					 PAGE_SIZE - pg_offset);
4793
4794		page = find_lock_page(inode->i_mapping, index);
4795		if (!page) {
4796			page_cache_sync_readahead(inode->i_mapping, &sctx->ra,
4797				NULL, index, last_index + 1 - index);
4798
4799			page = find_or_create_page(inode->i_mapping, index,
4800					GFP_KERNEL);
4801			if (!page) {
4802				ret = -ENOMEM;
4803				break;
4804			}
4805		}
4806
4807		if (PageReadahead(page)) {
4808			page_cache_async_readahead(inode->i_mapping, &sctx->ra,
4809				NULL, page, index, last_index + 1 - index);
4810		}
4811
4812		if (!PageUptodate(page)) {
4813			btrfs_readpage(NULL, page);
4814			lock_page(page);
4815			if (!PageUptodate(page)) {
4816				unlock_page(page);
4817				put_page(page);
4818				ret = -EIO;
4819				break;
4820			}
4821		}
4822
4823		addr = kmap(page);
4824		memcpy(sctx->read_buf + ret, addr + pg_offset, cur_len);
4825		kunmap(page);
4826		unlock_page(page);
4827		put_page(page);
4828		index++;
4829		pg_offset = 0;
4830		len -= cur_len;
4831		ret += cur_len;
4832	}
4833out:
4834	iput(inode);
4835	return ret;
4836}
4837
4838/*
4839 * Read some bytes from the current inode/file and send a write command to
4840 * user space.
4841 */
4842static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
4843{
4844	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
4845	int ret = 0;
4846	struct fs_path *p;
4847	ssize_t num_read = 0;
4848
4849	p = fs_path_alloc();
4850	if (!p)
4851		return -ENOMEM;
4852
4853	btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len);
4854
4855	num_read = fill_read_buf(sctx, offset, len);
4856	if (num_read <= 0) {
4857		if (num_read < 0)
4858			ret = num_read;
4859		goto out;
4860	}
4861
4862	ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
4863	if (ret < 0)
4864		goto out;
4865
4866	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
4867	if (ret < 0)
4868		goto out;
4869
4870	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
4871	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
4872	TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, num_read);
4873
4874	ret = send_cmd(sctx);
4875
4876tlv_put_failure:
4877out:
4878	fs_path_free(p);
4879	if (ret < 0)
4880		return ret;
4881	return num_read;
4882}
4883
4884/*
4885 * Send a clone command to user space.
4886 */
4887static int send_clone(struct send_ctx *sctx,
4888		      u64 offset, u32 len,
4889		      struct clone_root *clone_root)
4890{
4891	int ret = 0;
4892	struct fs_path *p;
4893	u64 gen;
4894
4895	btrfs_debug(sctx->send_root->fs_info,
4896		    "send_clone offset=%llu, len=%d, clone_root=%llu, clone_inode=%llu, clone_offset=%llu",
4897		    offset, len, clone_root->root->objectid, clone_root->ino,
4898		    clone_root->offset);
4899
4900	p = fs_path_alloc();
4901	if (!p)
4902		return -ENOMEM;
4903
4904	ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE);
4905	if (ret < 0)
4906		goto out;
4907
4908	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
4909	if (ret < 0)
4910		goto out;
4911
4912	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
4913	TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len);
4914	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
4915
4916	if (clone_root->root == sctx->send_root) {
4917		ret = get_inode_info(sctx->send_root, clone_root->ino, NULL,
4918				&gen, NULL, NULL, NULL, NULL);
4919		if (ret < 0)
4920			goto out;
4921		ret = get_cur_path(sctx, clone_root->ino, gen, p);
4922	} else {
4923		ret = get_inode_path(clone_root->root, clone_root->ino, p);
4924	}
4925	if (ret < 0)
4926		goto out;
4927
4928	/*
4929	 * If the parent we're using has a received_uuid set then use that as
4930	 * our clone source as that is what we will look for when doing a
4931	 * receive.
4932	 *
4933	 * This covers the case that we create a snapshot off of a received
4934	 * subvolume and then use that as the parent and try to receive on a
4935	 * different host.
4936	 */
4937	if (!btrfs_is_empty_uuid(clone_root->root->root_item.received_uuid))
4938		TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
4939			     clone_root->root->root_item.received_uuid);
4940	else
4941		TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
4942			     clone_root->root->root_item.uuid);
4943	TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
4944		    le64_to_cpu(clone_root->root->root_item.ctransid));
4945	TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p);
4946	TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET,
4947			clone_root->offset);
4948
4949	ret = send_cmd(sctx);
4950
4951tlv_put_failure:
4952out:
4953	fs_path_free(p);
4954	return ret;
4955}
4956
4957/*
4958 * Send an update extent command to user space.
4959 */
4960static int send_update_extent(struct send_ctx *sctx,
4961			      u64 offset, u32 len)
4962{
4963	int ret = 0;
4964	struct fs_path *p;
4965
4966	p = fs_path_alloc();
4967	if (!p)
4968		return -ENOMEM;
4969
4970	ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT);
4971	if (ret < 0)
4972		goto out;
4973
4974	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
4975	if (ret < 0)
4976		goto out;
4977
4978	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
4979	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
4980	TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len);
4981
4982	ret = send_cmd(sctx);
4983
4984tlv_put_failure:
4985out:
4986	fs_path_free(p);
4987	return ret;
4988}
4989
4990static int send_hole(struct send_ctx *sctx, u64 end)
4991{
4992	struct fs_path *p = NULL;
4993	u64 offset = sctx->cur_inode_last_extent;
4994	u64 len;
4995	int ret = 0;
4996
4997	if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
4998		return send_update_extent(sctx, offset, end - offset);
4999
5000	p = fs_path_alloc();
5001	if (!p)
5002		return -ENOMEM;
5003	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
5004	if (ret < 0)
5005		goto tlv_put_failure;
5006	memset(sctx->read_buf, 0, BTRFS_SEND_READ_SIZE);
5007	while (offset < end) {
5008		len = min_t(u64, end - offset, BTRFS_SEND_READ_SIZE);
5009
5010		ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
5011		if (ret < 0)
5012			break;
5013		TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
5014		TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
5015		TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, len);
5016		ret = send_cmd(sctx);
5017		if (ret < 0)
5018			break;
5019		offset += len;
5020	}
5021	sctx->cur_inode_next_write_offset = offset;
5022tlv_put_failure:
5023	fs_path_free(p);
5024	return ret;
5025}
5026
5027static int send_extent_data(struct send_ctx *sctx,
5028			    const u64 offset,
5029			    const u64 len)
5030{
5031	u64 sent = 0;
5032
5033	if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
5034		return send_update_extent(sctx, offset, len);
5035
5036	while (sent < len) {
5037		u64 size = len - sent;
5038		int ret;
5039
5040		if (size > BTRFS_SEND_READ_SIZE)
5041			size = BTRFS_SEND_READ_SIZE;
5042		ret = send_write(sctx, offset + sent, size);
5043		if (ret < 0)
5044			return ret;
5045		if (!ret)
5046			break;
5047		sent += ret;
5048	}
5049	return 0;
5050}
5051
5052static int clone_range(struct send_ctx *sctx,
5053		       struct clone_root *clone_root,
5054		       const u64 disk_byte,
5055		       u64 data_offset,
5056		       u64 offset,
5057		       u64 len)
5058{
5059	struct btrfs_path *path;
5060	struct btrfs_key key;
5061	int ret;
5062
5063	/*
5064	 * Prevent cloning from a zero offset with a length matching the sector
5065	 * size because in some scenarios this will make the receiver fail.
5066	 *
5067	 * For example, if in the source filesystem the extent at offset 0
5068	 * has a length of sectorsize and it was written using direct IO, then
5069	 * it can never be an inline extent (even if compression is enabled).
5070	 * Then this extent can be cloned in the original filesystem to a non
5071	 * zero file offset, but it may not be possible to clone in the
5072	 * destination filesystem because it can be inlined due to compression
5073	 * on the destination filesystem (as the receiver's write operations are
5074	 * always done using buffered IO). The same happens when the original
5075	 * filesystem does not have compression enabled but the destination
5076	 * filesystem has.
5077	 */
5078	if (clone_root->offset == 0 &&
5079	    len == sctx->send_root->fs_info->sectorsize)
5080		return send_extent_data(sctx, offset, len);
5081
5082	path = alloc_path_for_send();
5083	if (!path)
5084		return -ENOMEM;
5085
5086	/*
5087	 * We can't send a clone operation for the entire range if we find
5088	 * extent items in the respective range in the source file that
5089	 * refer to different extents or if we find holes.
5090	 * So check for that and do a mix of clone and regular write/copy
5091	 * operations if needed.
5092	 *
5093	 * Example:
5094	 *
5095	 * mkfs.btrfs -f /dev/sda
5096	 * mount /dev/sda /mnt
5097	 * xfs_io -f -c "pwrite -S 0xaa 0K 100K" /mnt/foo
5098	 * cp --reflink=always /mnt/foo /mnt/bar
5099	 * xfs_io -c "pwrite -S 0xbb 50K 50K" /mnt/foo
5100	 * btrfs subvolume snapshot -r /mnt /mnt/snap
5101	 *
5102	 * If when we send the snapshot and we are processing file bar (which
5103	 * has a higher inode number than foo) we blindly send a clone operation
5104	 * for the [0, 100K[ range from foo to bar, the receiver ends up getting
5105	 * a file bar that matches the content of file foo - iow, doesn't match
5106	 * the content from bar in the original filesystem.
5107	 */
5108	key.objectid = clone_root->ino;
5109	key.type = BTRFS_EXTENT_DATA_KEY;
5110	key.offset = clone_root->offset;
5111	ret = btrfs_search_slot(NULL, clone_root->root, &key, path, 0, 0);
5112	if (ret < 0)
5113		goto out;
5114	if (ret > 0 && path->slots[0] > 0) {
5115		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1);
5116		if (key.objectid == clone_root->ino &&
5117		    key.type == BTRFS_EXTENT_DATA_KEY)
5118			path->slots[0]--;
5119	}
5120
5121	while (true) {
5122		struct extent_buffer *leaf = path->nodes[0];
5123		int slot = path->slots[0];
5124		struct btrfs_file_extent_item *ei;
5125		u8 type;
5126		u64 ext_len;
5127		u64 clone_len;
5128
5129		if (slot >= btrfs_header_nritems(leaf)) {
5130			ret = btrfs_next_leaf(clone_root->root, path);
5131			if (ret < 0)
5132				goto out;
5133			else if (ret > 0)
5134				break;
5135			continue;
5136		}
5137
5138		btrfs_item_key_to_cpu(leaf, &key, slot);
5139
5140		/*
5141		 * We might have an implicit trailing hole (NO_HOLES feature
5142		 * enabled). We deal with it after leaving this loop.
5143		 */
5144		if (key.objectid != clone_root->ino ||
5145		    key.type != BTRFS_EXTENT_DATA_KEY)
5146			break;
5147
5148		ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5149		type = btrfs_file_extent_type(leaf, ei);
5150		if (type == BTRFS_FILE_EXTENT_INLINE) {
5151			ext_len = btrfs_file_extent_inline_len(leaf, slot, ei);
5152			ext_len = PAGE_ALIGN(ext_len);
5153		} else {
5154			ext_len = btrfs_file_extent_num_bytes(leaf, ei);
5155		}
5156
5157		if (key.offset + ext_len <= clone_root->offset)
5158			goto next;
5159
5160		if (key.offset > clone_root->offset) {
5161			/* Implicit hole, NO_HOLES feature enabled. */
5162			u64 hole_len = key.offset - clone_root->offset;
5163
5164			if (hole_len > len)
5165				hole_len = len;
5166			ret = send_extent_data(sctx, offset, hole_len);
5167			if (ret < 0)
5168				goto out;
5169
5170			len -= hole_len;
5171			if (len == 0)
5172				break;
5173			offset += hole_len;
5174			clone_root->offset += hole_len;
5175			data_offset += hole_len;
5176		}
5177
5178		if (key.offset >= clone_root->offset + len)
5179			break;
5180
5181		clone_len = min_t(u64, ext_len, len);
5182
5183		if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte &&
5184		    btrfs_file_extent_offset(leaf, ei) == data_offset)
5185			ret = send_clone(sctx, offset, clone_len, clone_root);
5186		else
5187			ret = send_extent_data(sctx, offset, clone_len);
5188
5189		if (ret < 0)
5190			goto out;
5191
5192		len -= clone_len;
5193		if (len == 0)
5194			break;
5195		offset += clone_len;
5196		clone_root->offset += clone_len;
5197		data_offset += clone_len;
5198next:
5199		path->slots[0]++;
5200	}
5201
5202	if (len > 0)
5203		ret = send_extent_data(sctx, offset, len);
5204	else
5205		ret = 0;
5206out:
5207	btrfs_free_path(path);
5208	return ret;
5209}
5210
5211static int send_write_or_clone(struct send_ctx *sctx,
5212			       struct btrfs_path *path,
5213			       struct btrfs_key *key,
5214			       struct clone_root *clone_root)
5215{
5216	int ret = 0;
5217	struct btrfs_file_extent_item *ei;
5218	u64 offset = key->offset;
 
5219	u64 len;
 
5220	u8 type;
5221	u64 bs = sctx->send_root->fs_info->sb->s_blocksize;
5222
5223	ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
5224			struct btrfs_file_extent_item);
5225	type = btrfs_file_extent_type(path->nodes[0], ei);
5226	if (type == BTRFS_FILE_EXTENT_INLINE) {
5227		len = btrfs_file_extent_inline_len(path->nodes[0],
5228						   path->slots[0], ei);
5229		/*
5230		 * it is possible the inline item won't cover the whole page,
5231		 * but there may be items after this page.  Make
5232		 * sure to send the whole thing
5233		 */
5234		len = PAGE_ALIGN(len);
5235	} else {
5236		len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
5237	}
5238
5239	if (offset >= sctx->cur_inode_size) {
5240		ret = 0;
5241		goto out;
5242	}
5243	if (offset + len > sctx->cur_inode_size)
5244		len = sctx->cur_inode_size - offset;
5245	if (len == 0) {
5246		ret = 0;
5247		goto out;
5248	}
5249
5250	if (clone_root && IS_ALIGNED(offset + len, bs)) {
5251		u64 disk_byte;
5252		u64 data_offset;
5253
5254		disk_byte = btrfs_file_extent_disk_bytenr(path->nodes[0], ei);
5255		data_offset = btrfs_file_extent_offset(path->nodes[0], ei);
5256		ret = clone_range(sctx, clone_root, disk_byte, data_offset,
5257				  offset, len);
5258	} else {
5259		ret = send_extent_data(sctx, offset, len);
 
 
 
 
 
 
 
 
 
 
 
5260	}
5261	sctx->cur_inode_next_write_offset = offset + len;
5262out:
5263	return ret;
5264}
5265
5266static int is_extent_unchanged(struct send_ctx *sctx,
5267			       struct btrfs_path *left_path,
5268			       struct btrfs_key *ekey)
5269{
5270	int ret = 0;
5271	struct btrfs_key key;
5272	struct btrfs_path *path = NULL;
5273	struct extent_buffer *eb;
5274	int slot;
5275	struct btrfs_key found_key;
5276	struct btrfs_file_extent_item *ei;
5277	u64 left_disknr;
5278	u64 right_disknr;
5279	u64 left_offset;
5280	u64 right_offset;
5281	u64 left_offset_fixed;
5282	u64 left_len;
5283	u64 right_len;
5284	u64 left_gen;
5285	u64 right_gen;
5286	u8 left_type;
5287	u8 right_type;
5288
5289	path = alloc_path_for_send();
5290	if (!path)
5291		return -ENOMEM;
5292
5293	eb = left_path->nodes[0];
5294	slot = left_path->slots[0];
5295	ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
5296	left_type = btrfs_file_extent_type(eb, ei);
5297
5298	if (left_type != BTRFS_FILE_EXTENT_REG) {
5299		ret = 0;
5300		goto out;
5301	}
5302	left_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
5303	left_len = btrfs_file_extent_num_bytes(eb, ei);
5304	left_offset = btrfs_file_extent_offset(eb, ei);
5305	left_gen = btrfs_file_extent_generation(eb, ei);
5306
5307	/*
5308	 * Following comments will refer to these graphics. L is the left
5309	 * extents which we are checking at the moment. 1-8 are the right
5310	 * extents that we iterate.
5311	 *
5312	 *       |-----L-----|
5313	 * |-1-|-2a-|-3-|-4-|-5-|-6-|
5314	 *
5315	 *       |-----L-----|
5316	 * |--1--|-2b-|...(same as above)
5317	 *
5318	 * Alternative situation. Happens on files where extents got split.
5319	 *       |-----L-----|
5320	 * |-----------7-----------|-6-|
5321	 *
5322	 * Alternative situation. Happens on files which got larger.
5323	 *       |-----L-----|
5324	 * |-8-|
5325	 * Nothing follows after 8.
5326	 */
5327
5328	key.objectid = ekey->objectid;
5329	key.type = BTRFS_EXTENT_DATA_KEY;
5330	key.offset = ekey->offset;
5331	ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0);
5332	if (ret < 0)
5333		goto out;
5334	if (ret) {
5335		ret = 0;
5336		goto out;
5337	}
5338
5339	/*
5340	 * Handle special case where the right side has no extents at all.
5341	 */
5342	eb = path->nodes[0];
5343	slot = path->slots[0];
5344	btrfs_item_key_to_cpu(eb, &found_key, slot);
5345	if (found_key.objectid != key.objectid ||
5346	    found_key.type != key.type) {
5347		/* If we're a hole then just pretend nothing changed */
5348		ret = (left_disknr) ? 0 : 1;
5349		goto out;
5350	}
5351
5352	/*
5353	 * We're now on 2a, 2b or 7.
5354	 */
5355	key = found_key;
5356	while (key.offset < ekey->offset + left_len) {
5357		ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
5358		right_type = btrfs_file_extent_type(eb, ei);
5359		if (right_type != BTRFS_FILE_EXTENT_REG &&
5360		    right_type != BTRFS_FILE_EXTENT_INLINE) {
5361			ret = 0;
5362			goto out;
5363		}
5364
5365		if (right_type == BTRFS_FILE_EXTENT_INLINE) {
5366			right_len = btrfs_file_extent_inline_len(eb, slot, ei);
5367			right_len = PAGE_ALIGN(right_len);
5368		} else {
5369			right_len = btrfs_file_extent_num_bytes(eb, ei);
5370		}
5371
5372		/*
5373		 * Are we at extent 8? If yes, we know the extent is changed.
5374		 * This may only happen on the first iteration.
5375		 */
5376		if (found_key.offset + right_len <= ekey->offset) {
5377			/* If we're a hole just pretend nothing changed */
5378			ret = (left_disknr) ? 0 : 1;
5379			goto out;
5380		}
5381
5382		/*
5383		 * We just wanted to see if when we have an inline extent, what
5384		 * follows it is a regular extent (wanted to check the above
5385		 * condition for inline extents too). This should normally not
5386		 * happen but it's possible for example when we have an inline
5387		 * compressed extent representing data with a size matching
5388		 * the page size (currently the same as sector size).
5389		 */
5390		if (right_type == BTRFS_FILE_EXTENT_INLINE) {
5391			ret = 0;
5392			goto out;
5393		}
5394
5395		right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
5396		right_offset = btrfs_file_extent_offset(eb, ei);
5397		right_gen = btrfs_file_extent_generation(eb, ei);
5398
5399		left_offset_fixed = left_offset;
5400		if (key.offset < ekey->offset) {
5401			/* Fix the right offset for 2a and 7. */
5402			right_offset += ekey->offset - key.offset;
5403		} else {
5404			/* Fix the left offset for all behind 2a and 2b */
5405			left_offset_fixed += key.offset - ekey->offset;
5406		}
5407
5408		/*
5409		 * Check if we have the same extent.
5410		 */
5411		if (left_disknr != right_disknr ||
5412		    left_offset_fixed != right_offset ||
5413		    left_gen != right_gen) {
5414			ret = 0;
5415			goto out;
5416		}
5417
5418		/*
5419		 * Go to the next extent.
5420		 */
5421		ret = btrfs_next_item(sctx->parent_root, path);
5422		if (ret < 0)
5423			goto out;
5424		if (!ret) {
5425			eb = path->nodes[0];
5426			slot = path->slots[0];
5427			btrfs_item_key_to_cpu(eb, &found_key, slot);
5428		}
5429		if (ret || found_key.objectid != key.objectid ||
5430		    found_key.type != key.type) {
5431			key.offset += right_len;
5432			break;
5433		}
5434		if (found_key.offset != key.offset + right_len) {
5435			ret = 0;
5436			goto out;
5437		}
5438		key = found_key;
5439	}
5440
5441	/*
5442	 * We're now behind the left extent (treat as unchanged) or at the end
5443	 * of the right side (treat as changed).
5444	 */
5445	if (key.offset >= ekey->offset + left_len)
5446		ret = 1;
5447	else
5448		ret = 0;
5449
5450
5451out:
5452	btrfs_free_path(path);
5453	return ret;
5454}
5455
5456static int get_last_extent(struct send_ctx *sctx, u64 offset)
5457{
5458	struct btrfs_path *path;
5459	struct btrfs_root *root = sctx->send_root;
5460	struct btrfs_file_extent_item *fi;
5461	struct btrfs_key key;
5462	u64 extent_end;
5463	u8 type;
5464	int ret;
5465
5466	path = alloc_path_for_send();
5467	if (!path)
5468		return -ENOMEM;
5469
5470	sctx->cur_inode_last_extent = 0;
5471
5472	key.objectid = sctx->cur_ino;
5473	key.type = BTRFS_EXTENT_DATA_KEY;
5474	key.offset = offset;
5475	ret = btrfs_search_slot_for_read(root, &key, path, 0, 1);
5476	if (ret < 0)
5477		goto out;
5478	ret = 0;
5479	btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
5480	if (key.objectid != sctx->cur_ino || key.type != BTRFS_EXTENT_DATA_KEY)
5481		goto out;
5482
5483	fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
5484			    struct btrfs_file_extent_item);
5485	type = btrfs_file_extent_type(path->nodes[0], fi);
5486	if (type == BTRFS_FILE_EXTENT_INLINE) {
5487		u64 size = btrfs_file_extent_inline_len(path->nodes[0],
5488							path->slots[0], fi);
5489		extent_end = ALIGN(key.offset + size,
5490				   sctx->send_root->fs_info->sectorsize);
5491	} else {
5492		extent_end = key.offset +
5493			btrfs_file_extent_num_bytes(path->nodes[0], fi);
5494	}
5495	sctx->cur_inode_last_extent = extent_end;
5496out:
5497	btrfs_free_path(path);
5498	return ret;
5499}
5500
5501static int range_is_hole_in_parent(struct send_ctx *sctx,
5502				   const u64 start,
5503				   const u64 end)
5504{
5505	struct btrfs_path *path;
5506	struct btrfs_key key;
5507	struct btrfs_root *root = sctx->parent_root;
5508	u64 search_start = start;
5509	int ret;
5510
5511	path = alloc_path_for_send();
5512	if (!path)
5513		return -ENOMEM;
5514
5515	key.objectid = sctx->cur_ino;
5516	key.type = BTRFS_EXTENT_DATA_KEY;
5517	key.offset = search_start;
5518	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5519	if (ret < 0)
5520		goto out;
5521	if (ret > 0 && path->slots[0] > 0)
5522		path->slots[0]--;
5523
5524	while (search_start < end) {
5525		struct extent_buffer *leaf = path->nodes[0];
5526		int slot = path->slots[0];
5527		struct btrfs_file_extent_item *fi;
5528		u64 extent_end;
5529
5530		if (slot >= btrfs_header_nritems(leaf)) {
5531			ret = btrfs_next_leaf(root, path);
5532			if (ret < 0)
5533				goto out;
5534			else if (ret > 0)
5535				break;
5536			continue;
5537		}
5538
5539		btrfs_item_key_to_cpu(leaf, &key, slot);
5540		if (key.objectid < sctx->cur_ino ||
5541		    key.type < BTRFS_EXTENT_DATA_KEY)
5542			goto next;
5543		if (key.objectid > sctx->cur_ino ||
5544		    key.type > BTRFS_EXTENT_DATA_KEY ||
5545		    key.offset >= end)
5546			break;
5547
5548		fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5549		if (btrfs_file_extent_type(leaf, fi) ==
5550		    BTRFS_FILE_EXTENT_INLINE) {
5551			u64 size = btrfs_file_extent_inline_len(leaf, slot, fi);
5552
5553			extent_end = ALIGN(key.offset + size,
5554					   root->fs_info->sectorsize);
5555		} else {
5556			extent_end = key.offset +
5557				btrfs_file_extent_num_bytes(leaf, fi);
5558		}
5559		if (extent_end <= start)
5560			goto next;
5561		if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) {
5562			search_start = extent_end;
5563			goto next;
5564		}
5565		ret = 0;
5566		goto out;
5567next:
5568		path->slots[0]++;
5569	}
5570	ret = 1;
5571out:
5572	btrfs_free_path(path);
5573	return ret;
5574}
5575
5576static int maybe_send_hole(struct send_ctx *sctx, struct btrfs_path *path,
5577			   struct btrfs_key *key)
5578{
5579	struct btrfs_file_extent_item *fi;
5580	u64 extent_end;
5581	u8 type;
5582	int ret = 0;
5583
5584	if (sctx->cur_ino != key->objectid || !need_send_hole(sctx))
5585		return 0;
5586
5587	if (sctx->cur_inode_last_extent == (u64)-1) {
5588		ret = get_last_extent(sctx, key->offset - 1);
5589		if (ret)
5590			return ret;
5591	}
5592
5593	fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
5594			    struct btrfs_file_extent_item);
5595	type = btrfs_file_extent_type(path->nodes[0], fi);
5596	if (type == BTRFS_FILE_EXTENT_INLINE) {
5597		u64 size = btrfs_file_extent_inline_len(path->nodes[0],
5598							path->slots[0], fi);
5599		extent_end = ALIGN(key->offset + size,
5600				   sctx->send_root->fs_info->sectorsize);
5601	} else {
5602		extent_end = key->offset +
5603			btrfs_file_extent_num_bytes(path->nodes[0], fi);
5604	}
5605
5606	if (path->slots[0] == 0 &&
5607	    sctx->cur_inode_last_extent < key->offset) {
5608		/*
5609		 * We might have skipped entire leafs that contained only
5610		 * file extent items for our current inode. These leafs have
5611		 * a generation number smaller (older) than the one in the
5612		 * current leaf and the leaf our last extent came from, and
5613		 * are located between these 2 leafs.
5614		 */
5615		ret = get_last_extent(sctx, key->offset - 1);
5616		if (ret)
5617			return ret;
5618	}
5619
5620	if (sctx->cur_inode_last_extent < key->offset) {
5621		ret = range_is_hole_in_parent(sctx,
5622					      sctx->cur_inode_last_extent,
5623					      key->offset);
5624		if (ret < 0)
5625			return ret;
5626		else if (ret == 0)
5627			ret = send_hole(sctx, key->offset);
5628		else
5629			ret = 0;
5630	}
5631	sctx->cur_inode_last_extent = extent_end;
5632	return ret;
5633}
5634
5635static int process_extent(struct send_ctx *sctx,
5636			  struct btrfs_path *path,
5637			  struct btrfs_key *key)
5638{
5639	struct clone_root *found_clone = NULL;
5640	int ret = 0;
5641
5642	if (S_ISLNK(sctx->cur_inode_mode))
5643		return 0;
5644
5645	if (sctx->parent_root && !sctx->cur_inode_new) {
5646		ret = is_extent_unchanged(sctx, path, key);
5647		if (ret < 0)
5648			goto out;
5649		if (ret) {
5650			ret = 0;
5651			goto out_hole;
5652		}
5653	} else {
5654		struct btrfs_file_extent_item *ei;
5655		u8 type;
5656
5657		ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
5658				    struct btrfs_file_extent_item);
5659		type = btrfs_file_extent_type(path->nodes[0], ei);
5660		if (type == BTRFS_FILE_EXTENT_PREALLOC ||
5661		    type == BTRFS_FILE_EXTENT_REG) {
5662			/*
5663			 * The send spec does not have a prealloc command yet,
5664			 * so just leave a hole for prealloc'ed extents until
5665			 * we have enough commands queued up to justify rev'ing
5666			 * the send spec.
5667			 */
5668			if (type == BTRFS_FILE_EXTENT_PREALLOC) {
5669				ret = 0;
5670				goto out;
5671			}
5672
5673			/* Have a hole, just skip it. */
5674			if (btrfs_file_extent_disk_bytenr(path->nodes[0], ei) == 0) {
5675				ret = 0;
5676				goto out;
5677			}
5678		}
5679	}
5680
5681	ret = find_extent_clone(sctx, path, key->objectid, key->offset,
5682			sctx->cur_inode_size, &found_clone);
5683	if (ret != -ENOENT && ret < 0)
5684		goto out;
5685
5686	ret = send_write_or_clone(sctx, path, key, found_clone);
5687	if (ret)
5688		goto out;
5689out_hole:
5690	ret = maybe_send_hole(sctx, path, key);
5691out:
5692	return ret;
5693}
5694
5695static int process_all_extents(struct send_ctx *sctx)
5696{
5697	int ret;
5698	struct btrfs_root *root;
5699	struct btrfs_path *path;
5700	struct btrfs_key key;
5701	struct btrfs_key found_key;
5702	struct extent_buffer *eb;
5703	int slot;
5704
5705	root = sctx->send_root;
5706	path = alloc_path_for_send();
5707	if (!path)
5708		return -ENOMEM;
5709
5710	key.objectid = sctx->cmp_key->objectid;
5711	key.type = BTRFS_EXTENT_DATA_KEY;
5712	key.offset = 0;
5713	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5714	if (ret < 0)
5715		goto out;
5716
5717	while (1) {
5718		eb = path->nodes[0];
5719		slot = path->slots[0];
5720
5721		if (slot >= btrfs_header_nritems(eb)) {
5722			ret = btrfs_next_leaf(root, path);
5723			if (ret < 0) {
5724				goto out;
5725			} else if (ret > 0) {
5726				ret = 0;
5727				break;
5728			}
5729			continue;
5730		}
5731
5732		btrfs_item_key_to_cpu(eb, &found_key, slot);
5733
5734		if (found_key.objectid != key.objectid ||
5735		    found_key.type != key.type) {
5736			ret = 0;
5737			goto out;
5738		}
5739
5740		ret = process_extent(sctx, path, &found_key);
5741		if (ret < 0)
5742			goto out;
5743
5744		path->slots[0]++;
5745	}
5746
5747out:
5748	btrfs_free_path(path);
5749	return ret;
5750}
5751
5752static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end,
5753					   int *pending_move,
5754					   int *refs_processed)
5755{
5756	int ret = 0;
5757
5758	if (sctx->cur_ino == 0)
5759		goto out;
5760	if (!at_end && sctx->cur_ino == sctx->cmp_key->objectid &&
5761	    sctx->cmp_key->type <= BTRFS_INODE_EXTREF_KEY)
5762		goto out;
5763	if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs))
5764		goto out;
5765
5766	ret = process_recorded_refs(sctx, pending_move);
5767	if (ret < 0)
5768		goto out;
5769
5770	*refs_processed = 1;
5771out:
5772	return ret;
5773}
5774
5775static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
5776{
5777	int ret = 0;
5778	u64 left_mode;
5779	u64 left_uid;
5780	u64 left_gid;
5781	u64 right_mode;
5782	u64 right_uid;
5783	u64 right_gid;
5784	int need_chmod = 0;
5785	int need_chown = 0;
5786	int need_truncate = 1;
5787	int pending_move = 0;
5788	int refs_processed = 0;
5789
5790	ret = process_recorded_refs_if_needed(sctx, at_end, &pending_move,
5791					      &refs_processed);
5792	if (ret < 0)
5793		goto out;
5794
5795	/*
5796	 * We have processed the refs and thus need to advance send_progress.
5797	 * Now, calls to get_cur_xxx will take the updated refs of the current
5798	 * inode into account.
5799	 *
5800	 * On the other hand, if our current inode is a directory and couldn't
5801	 * be moved/renamed because its parent was renamed/moved too and it has
5802	 * a higher inode number, we can only move/rename our current inode
5803	 * after we moved/renamed its parent. Therefore in this case operate on
5804	 * the old path (pre move/rename) of our current inode, and the
5805	 * move/rename will be performed later.
5806	 */
5807	if (refs_processed && !pending_move)
5808		sctx->send_progress = sctx->cur_ino + 1;
5809
5810	if (sctx->cur_ino == 0 || sctx->cur_inode_deleted)
5811		goto out;
5812	if (!at_end && sctx->cmp_key->objectid == sctx->cur_ino)
5813		goto out;
5814
5815	ret = get_inode_info(sctx->send_root, sctx->cur_ino, NULL, NULL,
5816			&left_mode, &left_uid, &left_gid, NULL);
5817	if (ret < 0)
5818		goto out;
5819
5820	if (!sctx->parent_root || sctx->cur_inode_new) {
5821		need_chown = 1;
5822		if (!S_ISLNK(sctx->cur_inode_mode))
5823			need_chmod = 1;
5824		if (sctx->cur_inode_next_write_offset == sctx->cur_inode_size)
5825			need_truncate = 0;
5826	} else {
5827		u64 old_size;
5828
5829		ret = get_inode_info(sctx->parent_root, sctx->cur_ino,
5830				&old_size, NULL, &right_mode, &right_uid,
5831				&right_gid, NULL);
5832		if (ret < 0)
5833			goto out;
5834
5835		if (left_uid != right_uid || left_gid != right_gid)
5836			need_chown = 1;
5837		if (!S_ISLNK(sctx->cur_inode_mode) && left_mode != right_mode)
5838			need_chmod = 1;
5839		if ((old_size == sctx->cur_inode_size) ||
5840		    (sctx->cur_inode_size > old_size &&
5841		     sctx->cur_inode_next_write_offset == sctx->cur_inode_size))
5842			need_truncate = 0;
5843	}
5844
5845	if (S_ISREG(sctx->cur_inode_mode)) {
5846		if (need_send_hole(sctx)) {
5847			if (sctx->cur_inode_last_extent == (u64)-1 ||
5848			    sctx->cur_inode_last_extent <
5849			    sctx->cur_inode_size) {
5850				ret = get_last_extent(sctx, (u64)-1);
5851				if (ret)
5852					goto out;
5853			}
5854			if (sctx->cur_inode_last_extent <
5855			    sctx->cur_inode_size) {
5856				ret = send_hole(sctx, sctx->cur_inode_size);
5857				if (ret)
5858					goto out;
5859			}
5860		}
5861		if (need_truncate) {
5862			ret = send_truncate(sctx, sctx->cur_ino,
5863					    sctx->cur_inode_gen,
5864					    sctx->cur_inode_size);
5865			if (ret < 0)
5866				goto out;
5867		}
5868	}
5869
5870	if (need_chown) {
5871		ret = send_chown(sctx, sctx->cur_ino, sctx->cur_inode_gen,
5872				left_uid, left_gid);
5873		if (ret < 0)
5874			goto out;
5875	}
5876	if (need_chmod) {
5877		ret = send_chmod(sctx, sctx->cur_ino, sctx->cur_inode_gen,
5878				left_mode);
5879		if (ret < 0)
5880			goto out;
5881	}
5882
5883	/*
5884	 * If other directory inodes depended on our current directory
5885	 * inode's move/rename, now do their move/rename operations.
5886	 */
5887	if (!is_waiting_for_move(sctx, sctx->cur_ino)) {
5888		ret = apply_children_dir_moves(sctx);
5889		if (ret)
5890			goto out;
5891		/*
5892		 * Need to send that every time, no matter if it actually
5893		 * changed between the two trees as we have done changes to
5894		 * the inode before. If our inode is a directory and it's
5895		 * waiting to be moved/renamed, we will send its utimes when
5896		 * it's moved/renamed, therefore we don't need to do it here.
5897		 */
5898		sctx->send_progress = sctx->cur_ino + 1;
5899		ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen);
5900		if (ret < 0)
5901			goto out;
5902	}
5903
5904out:
5905	return ret;
5906}
5907
5908static int changed_inode(struct send_ctx *sctx,
5909			 enum btrfs_compare_tree_result result)
5910{
5911	int ret = 0;
5912	struct btrfs_key *key = sctx->cmp_key;
5913	struct btrfs_inode_item *left_ii = NULL;
5914	struct btrfs_inode_item *right_ii = NULL;
5915	u64 left_gen = 0;
5916	u64 right_gen = 0;
5917
5918	sctx->cur_ino = key->objectid;
5919	sctx->cur_inode_new_gen = 0;
5920	sctx->cur_inode_last_extent = (u64)-1;
5921	sctx->cur_inode_next_write_offset = 0;
5922
5923	/*
5924	 * Set send_progress to current inode. This will tell all get_cur_xxx
5925	 * functions that the current inode's refs are not updated yet. Later,
5926	 * when process_recorded_refs is finished, it is set to cur_ino + 1.
5927	 */
5928	sctx->send_progress = sctx->cur_ino;
5929
5930	if (result == BTRFS_COMPARE_TREE_NEW ||
5931	    result == BTRFS_COMPARE_TREE_CHANGED) {
5932		left_ii = btrfs_item_ptr(sctx->left_path->nodes[0],
5933				sctx->left_path->slots[0],
5934				struct btrfs_inode_item);
5935		left_gen = btrfs_inode_generation(sctx->left_path->nodes[0],
5936				left_ii);
5937	} else {
5938		right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
5939				sctx->right_path->slots[0],
5940				struct btrfs_inode_item);
5941		right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
5942				right_ii);
5943	}
5944	if (result == BTRFS_COMPARE_TREE_CHANGED) {
5945		right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
5946				sctx->right_path->slots[0],
5947				struct btrfs_inode_item);
5948
5949		right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
5950				right_ii);
5951
5952		/*
5953		 * The cur_ino = root dir case is special here. We can't treat
5954		 * the inode as deleted+reused because it would generate a
5955		 * stream that tries to delete/mkdir the root dir.
5956		 */
5957		if (left_gen != right_gen &&
5958		    sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
5959			sctx->cur_inode_new_gen = 1;
5960	}
5961
5962	if (result == BTRFS_COMPARE_TREE_NEW) {
5963		sctx->cur_inode_gen = left_gen;
5964		sctx->cur_inode_new = 1;
5965		sctx->cur_inode_deleted = 0;
5966		sctx->cur_inode_size = btrfs_inode_size(
5967				sctx->left_path->nodes[0], left_ii);
5968		sctx->cur_inode_mode = btrfs_inode_mode(
5969				sctx->left_path->nodes[0], left_ii);
5970		sctx->cur_inode_rdev = btrfs_inode_rdev(
5971				sctx->left_path->nodes[0], left_ii);
5972		if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
5973			ret = send_create_inode_if_needed(sctx);
5974	} else if (result == BTRFS_COMPARE_TREE_DELETED) {
5975		sctx->cur_inode_gen = right_gen;
5976		sctx->cur_inode_new = 0;
5977		sctx->cur_inode_deleted = 1;
5978		sctx->cur_inode_size = btrfs_inode_size(
5979				sctx->right_path->nodes[0], right_ii);
5980		sctx->cur_inode_mode = btrfs_inode_mode(
5981				sctx->right_path->nodes[0], right_ii);
5982	} else if (result == BTRFS_COMPARE_TREE_CHANGED) {
5983		/*
5984		 * We need to do some special handling in case the inode was
5985		 * reported as changed with a changed generation number. This
5986		 * means that the original inode was deleted and new inode
5987		 * reused the same inum. So we have to treat the old inode as
5988		 * deleted and the new one as new.
5989		 */
5990		if (sctx->cur_inode_new_gen) {
5991			/*
5992			 * First, process the inode as if it was deleted.
5993			 */
5994			sctx->cur_inode_gen = right_gen;
5995			sctx->cur_inode_new = 0;
5996			sctx->cur_inode_deleted = 1;
5997			sctx->cur_inode_size = btrfs_inode_size(
5998					sctx->right_path->nodes[0], right_ii);
5999			sctx->cur_inode_mode = btrfs_inode_mode(
6000					sctx->right_path->nodes[0], right_ii);
6001			ret = process_all_refs(sctx,
6002					BTRFS_COMPARE_TREE_DELETED);
6003			if (ret < 0)
6004				goto out;
6005
6006			/*
6007			 * Now process the inode as if it was new.
6008			 */
6009			sctx->cur_inode_gen = left_gen;
6010			sctx->cur_inode_new = 1;
6011			sctx->cur_inode_deleted = 0;
6012			sctx->cur_inode_size = btrfs_inode_size(
6013					sctx->left_path->nodes[0], left_ii);
6014			sctx->cur_inode_mode = btrfs_inode_mode(
6015					sctx->left_path->nodes[0], left_ii);
6016			sctx->cur_inode_rdev = btrfs_inode_rdev(
6017					sctx->left_path->nodes[0], left_ii);
6018			ret = send_create_inode_if_needed(sctx);
6019			if (ret < 0)
6020				goto out;
6021
6022			ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW);
6023			if (ret < 0)
6024				goto out;
6025			/*
6026			 * Advance send_progress now as we did not get into
6027			 * process_recorded_refs_if_needed in the new_gen case.
6028			 */
6029			sctx->send_progress = sctx->cur_ino + 1;
6030
6031			/*
6032			 * Now process all extents and xattrs of the inode as if
6033			 * they were all new.
6034			 */
6035			ret = process_all_extents(sctx);
6036			if (ret < 0)
6037				goto out;
6038			ret = process_all_new_xattrs(sctx);
6039			if (ret < 0)
6040				goto out;
6041		} else {
6042			sctx->cur_inode_gen = left_gen;
6043			sctx->cur_inode_new = 0;
6044			sctx->cur_inode_new_gen = 0;
6045			sctx->cur_inode_deleted = 0;
6046			sctx->cur_inode_size = btrfs_inode_size(
6047					sctx->left_path->nodes[0], left_ii);
6048			sctx->cur_inode_mode = btrfs_inode_mode(
6049					sctx->left_path->nodes[0], left_ii);
6050		}
6051	}
6052
6053out:
6054	return ret;
6055}
6056
6057/*
6058 * We have to process new refs before deleted refs, but compare_trees gives us
6059 * the new and deleted refs mixed. To fix this, we record the new/deleted refs
6060 * first and later process them in process_recorded_refs.
6061 * For the cur_inode_new_gen case, we skip recording completely because
6062 * changed_inode did already initiate processing of refs. The reason for this is
6063 * that in this case, compare_tree actually compares the refs of 2 different
6064 * inodes. To fix this, process_all_refs is used in changed_inode to handle all
6065 * refs of the right tree as deleted and all refs of the left tree as new.
6066 */
6067static int changed_ref(struct send_ctx *sctx,
6068		       enum btrfs_compare_tree_result result)
6069{
6070	int ret = 0;
6071
6072	if (sctx->cur_ino != sctx->cmp_key->objectid) {
6073		inconsistent_snapshot_error(sctx, result, "reference");
6074		return -EIO;
6075	}
6076
6077	if (!sctx->cur_inode_new_gen &&
6078	    sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) {
6079		if (result == BTRFS_COMPARE_TREE_NEW)
6080			ret = record_new_ref(sctx);
6081		else if (result == BTRFS_COMPARE_TREE_DELETED)
6082			ret = record_deleted_ref(sctx);
6083		else if (result == BTRFS_COMPARE_TREE_CHANGED)
6084			ret = record_changed_ref(sctx);
6085	}
6086
6087	return ret;
6088}
6089
6090/*
6091 * Process new/deleted/changed xattrs. We skip processing in the
6092 * cur_inode_new_gen case because changed_inode did already initiate processing
6093 * of xattrs. The reason is the same as in changed_ref
6094 */
6095static int changed_xattr(struct send_ctx *sctx,
6096			 enum btrfs_compare_tree_result result)
6097{
6098	int ret = 0;
6099
6100	if (sctx->cur_ino != sctx->cmp_key->objectid) {
6101		inconsistent_snapshot_error(sctx, result, "xattr");
6102		return -EIO;
6103	}
6104
6105	if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
6106		if (result == BTRFS_COMPARE_TREE_NEW)
6107			ret = process_new_xattr(sctx);
6108		else if (result == BTRFS_COMPARE_TREE_DELETED)
6109			ret = process_deleted_xattr(sctx);
6110		else if (result == BTRFS_COMPARE_TREE_CHANGED)
6111			ret = process_changed_xattr(sctx);
6112	}
6113
6114	return ret;
6115}
6116
6117/*
6118 * Process new/deleted/changed extents. We skip processing in the
6119 * cur_inode_new_gen case because changed_inode did already initiate processing
6120 * of extents. The reason is the same as in changed_ref
6121 */
6122static int changed_extent(struct send_ctx *sctx,
6123			  enum btrfs_compare_tree_result result)
6124{
6125	int ret = 0;
6126
6127	if (sctx->cur_ino != sctx->cmp_key->objectid) {
6128
6129		if (result == BTRFS_COMPARE_TREE_CHANGED) {
6130			struct extent_buffer *leaf_l;
6131			struct extent_buffer *leaf_r;
6132			struct btrfs_file_extent_item *ei_l;
6133			struct btrfs_file_extent_item *ei_r;
6134
6135			leaf_l = sctx->left_path->nodes[0];
6136			leaf_r = sctx->right_path->nodes[0];
6137			ei_l = btrfs_item_ptr(leaf_l,
6138					      sctx->left_path->slots[0],
6139					      struct btrfs_file_extent_item);
6140			ei_r = btrfs_item_ptr(leaf_r,
6141					      sctx->right_path->slots[0],
6142					      struct btrfs_file_extent_item);
6143
6144			/*
6145			 * We may have found an extent item that has changed
6146			 * only its disk_bytenr field and the corresponding
6147			 * inode item was not updated. This case happens due to
6148			 * very specific timings during relocation when a leaf
6149			 * that contains file extent items is COWed while
6150			 * relocation is ongoing and its in the stage where it
6151			 * updates data pointers. So when this happens we can
6152			 * safely ignore it since we know it's the same extent,
6153			 * but just at different logical and physical locations
6154			 * (when an extent is fully replaced with a new one, we
6155			 * know the generation number must have changed too,
6156			 * since snapshot creation implies committing the current
6157			 * transaction, and the inode item must have been updated
6158			 * as well).
6159			 * This replacement of the disk_bytenr happens at
6160			 * relocation.c:replace_file_extents() through
6161			 * relocation.c:btrfs_reloc_cow_block().
6162			 */
6163			if (btrfs_file_extent_generation(leaf_l, ei_l) ==
6164			    btrfs_file_extent_generation(leaf_r, ei_r) &&
6165			    btrfs_file_extent_ram_bytes(leaf_l, ei_l) ==
6166			    btrfs_file_extent_ram_bytes(leaf_r, ei_r) &&
6167			    btrfs_file_extent_compression(leaf_l, ei_l) ==
6168			    btrfs_file_extent_compression(leaf_r, ei_r) &&
6169			    btrfs_file_extent_encryption(leaf_l, ei_l) ==
6170			    btrfs_file_extent_encryption(leaf_r, ei_r) &&
6171			    btrfs_file_extent_other_encoding(leaf_l, ei_l) ==
6172			    btrfs_file_extent_other_encoding(leaf_r, ei_r) &&
6173			    btrfs_file_extent_type(leaf_l, ei_l) ==
6174			    btrfs_file_extent_type(leaf_r, ei_r) &&
6175			    btrfs_file_extent_disk_bytenr(leaf_l, ei_l) !=
6176			    btrfs_file_extent_disk_bytenr(leaf_r, ei_r) &&
6177			    btrfs_file_extent_disk_num_bytes(leaf_l, ei_l) ==
6178			    btrfs_file_extent_disk_num_bytes(leaf_r, ei_r) &&
6179			    btrfs_file_extent_offset(leaf_l, ei_l) ==
6180			    btrfs_file_extent_offset(leaf_r, ei_r) &&
6181			    btrfs_file_extent_num_bytes(leaf_l, ei_l) ==
6182			    btrfs_file_extent_num_bytes(leaf_r, ei_r))
6183				return 0;
6184		}
6185
6186		inconsistent_snapshot_error(sctx, result, "extent");
6187		return -EIO;
6188	}
6189
6190	if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
6191		if (result != BTRFS_COMPARE_TREE_DELETED)
6192			ret = process_extent(sctx, sctx->left_path,
6193					sctx->cmp_key);
6194	}
6195
6196	return ret;
6197}
6198
6199static int dir_changed(struct send_ctx *sctx, u64 dir)
6200{
6201	u64 orig_gen, new_gen;
6202	int ret;
6203
6204	ret = get_inode_info(sctx->send_root, dir, NULL, &new_gen, NULL, NULL,
6205			     NULL, NULL);
6206	if (ret)
6207		return ret;
6208
6209	ret = get_inode_info(sctx->parent_root, dir, NULL, &orig_gen, NULL,
6210			     NULL, NULL, NULL);
6211	if (ret)
6212		return ret;
6213
6214	return (orig_gen != new_gen) ? 1 : 0;
6215}
6216
6217static int compare_refs(struct send_ctx *sctx, struct btrfs_path *path,
6218			struct btrfs_key *key)
6219{
6220	struct btrfs_inode_extref *extref;
6221	struct extent_buffer *leaf;
6222	u64 dirid = 0, last_dirid = 0;
6223	unsigned long ptr;
6224	u32 item_size;
6225	u32 cur_offset = 0;
6226	int ref_name_len;
6227	int ret = 0;
6228
6229	/* Easy case, just check this one dirid */
6230	if (key->type == BTRFS_INODE_REF_KEY) {
6231		dirid = key->offset;
6232
6233		ret = dir_changed(sctx, dirid);
6234		goto out;
6235	}
6236
6237	leaf = path->nodes[0];
6238	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
6239	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
6240	while (cur_offset < item_size) {
6241		extref = (struct btrfs_inode_extref *)(ptr +
6242						       cur_offset);
6243		dirid = btrfs_inode_extref_parent(leaf, extref);
6244		ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
6245		cur_offset += ref_name_len + sizeof(*extref);
6246		if (dirid == last_dirid)
6247			continue;
6248		ret = dir_changed(sctx, dirid);
6249		if (ret)
6250			break;
6251		last_dirid = dirid;
6252	}
6253out:
6254	return ret;
6255}
6256
6257/*
6258 * Updates compare related fields in sctx and simply forwards to the actual
6259 * changed_xxx functions.
6260 */
6261static int changed_cb(struct btrfs_path *left_path,
 
 
6262		      struct btrfs_path *right_path,
6263		      struct btrfs_key *key,
6264		      enum btrfs_compare_tree_result result,
6265		      void *ctx)
6266{
6267	int ret = 0;
6268	struct send_ctx *sctx = ctx;
6269
6270	if (result == BTRFS_COMPARE_TREE_SAME) {
6271		if (key->type == BTRFS_INODE_REF_KEY ||
6272		    key->type == BTRFS_INODE_EXTREF_KEY) {
6273			ret = compare_refs(sctx, left_path, key);
6274			if (!ret)
6275				return 0;
6276			if (ret < 0)
6277				return ret;
6278		} else if (key->type == BTRFS_EXTENT_DATA_KEY) {
6279			return maybe_send_hole(sctx, left_path, key);
6280		} else {
6281			return 0;
6282		}
6283		result = BTRFS_COMPARE_TREE_CHANGED;
6284		ret = 0;
6285	}
6286
6287	sctx->left_path = left_path;
6288	sctx->right_path = right_path;
6289	sctx->cmp_key = key;
6290
6291	ret = finish_inode_if_needed(sctx, 0);
6292	if (ret < 0)
6293		goto out;
6294
6295	/* Ignore non-FS objects */
6296	if (key->objectid == BTRFS_FREE_INO_OBJECTID ||
6297	    key->objectid == BTRFS_FREE_SPACE_OBJECTID)
6298		goto out;
6299
6300	if (key->type == BTRFS_INODE_ITEM_KEY)
6301		ret = changed_inode(sctx, result);
6302	else if (key->type == BTRFS_INODE_REF_KEY ||
6303		 key->type == BTRFS_INODE_EXTREF_KEY)
6304		ret = changed_ref(sctx, result);
6305	else if (key->type == BTRFS_XATTR_ITEM_KEY)
6306		ret = changed_xattr(sctx, result);
6307	else if (key->type == BTRFS_EXTENT_DATA_KEY)
6308		ret = changed_extent(sctx, result);
6309
6310out:
6311	return ret;
6312}
6313
6314static int full_send_tree(struct send_ctx *sctx)
6315{
6316	int ret;
6317	struct btrfs_root *send_root = sctx->send_root;
6318	struct btrfs_key key;
6319	struct btrfs_key found_key;
6320	struct btrfs_path *path;
6321	struct extent_buffer *eb;
6322	int slot;
6323
6324	path = alloc_path_for_send();
6325	if (!path)
6326		return -ENOMEM;
6327
6328	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
6329	key.type = BTRFS_INODE_ITEM_KEY;
6330	key.offset = 0;
6331
6332	ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0);
6333	if (ret < 0)
6334		goto out;
6335	if (ret)
6336		goto out_finish;
6337
6338	while (1) {
6339		eb = path->nodes[0];
6340		slot = path->slots[0];
6341		btrfs_item_key_to_cpu(eb, &found_key, slot);
6342
6343		ret = changed_cb(path, NULL, &found_key,
6344				 BTRFS_COMPARE_TREE_NEW, sctx);
6345		if (ret < 0)
6346			goto out;
6347
6348		key.objectid = found_key.objectid;
6349		key.type = found_key.type;
6350		key.offset = found_key.offset + 1;
6351
6352		ret = btrfs_next_item(send_root, path);
6353		if (ret < 0)
6354			goto out;
6355		if (ret) {
6356			ret  = 0;
6357			break;
6358		}
6359	}
6360
6361out_finish:
6362	ret = finish_inode_if_needed(sctx, 1);
6363
6364out:
6365	btrfs_free_path(path);
6366	return ret;
6367}
6368
6369static int send_subvol(struct send_ctx *sctx)
6370{
6371	int ret;
6372
6373	if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_STREAM_HEADER)) {
6374		ret = send_header(sctx);
6375		if (ret < 0)
6376			goto out;
6377	}
6378
6379	ret = send_subvol_begin(sctx);
6380	if (ret < 0)
6381		goto out;
6382
6383	if (sctx->parent_root) {
6384		ret = btrfs_compare_trees(sctx->send_root, sctx->parent_root,
6385				changed_cb, sctx);
6386		if (ret < 0)
6387			goto out;
6388		ret = finish_inode_if_needed(sctx, 1);
6389		if (ret < 0)
6390			goto out;
6391	} else {
6392		ret = full_send_tree(sctx);
6393		if (ret < 0)
6394			goto out;
6395	}
6396
6397out:
6398	free_recorded_refs(sctx);
6399	return ret;
6400}
6401
6402/*
6403 * If orphan cleanup did remove any orphans from a root, it means the tree
6404 * was modified and therefore the commit root is not the same as the current
6405 * root anymore. This is a problem, because send uses the commit root and
6406 * therefore can see inode items that don't exist in the current root anymore,
6407 * and for example make calls to btrfs_iget, which will do tree lookups based
6408 * on the current root and not on the commit root. Those lookups will fail,
6409 * returning a -ESTALE error, and making send fail with that error. So make
6410 * sure a send does not see any orphans we have just removed, and that it will
6411 * see the same inodes regardless of whether a transaction commit happened
6412 * before it started (meaning that the commit root will be the same as the
6413 * current root) or not.
6414 */
6415static int ensure_commit_roots_uptodate(struct send_ctx *sctx)
6416{
6417	int i;
6418	struct btrfs_trans_handle *trans = NULL;
6419
6420again:
6421	if (sctx->parent_root &&
6422	    sctx->parent_root->node != sctx->parent_root->commit_root)
6423		goto commit_trans;
6424
6425	for (i = 0; i < sctx->clone_roots_cnt; i++)
6426		if (sctx->clone_roots[i].root->node !=
6427		    sctx->clone_roots[i].root->commit_root)
6428			goto commit_trans;
6429
6430	if (trans)
6431		return btrfs_end_transaction(trans);
6432
6433	return 0;
6434
6435commit_trans:
6436	/* Use any root, all fs roots will get their commit roots updated. */
6437	if (!trans) {
6438		trans = btrfs_join_transaction(sctx->send_root);
6439		if (IS_ERR(trans))
6440			return PTR_ERR(trans);
6441		goto again;
6442	}
6443
6444	return btrfs_commit_transaction(trans);
6445}
6446
6447static void btrfs_root_dec_send_in_progress(struct btrfs_root* root)
6448{
6449	spin_lock(&root->root_item_lock);
6450	root->send_in_progress--;
6451	/*
6452	 * Not much left to do, we don't know why it's unbalanced and
6453	 * can't blindly reset it to 0.
6454	 */
6455	if (root->send_in_progress < 0)
6456		btrfs_err(root->fs_info,
6457			  "send_in_progres unbalanced %d root %llu",
6458			  root->send_in_progress, root->root_key.objectid);
6459	spin_unlock(&root->root_item_lock);
6460}
6461
6462long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
6463{
6464	int ret = 0;
6465	struct btrfs_root *send_root = BTRFS_I(file_inode(mnt_file))->root;
6466	struct btrfs_fs_info *fs_info = send_root->fs_info;
6467	struct btrfs_root *clone_root;
 
 
6468	struct btrfs_key key;
6469	struct send_ctx *sctx = NULL;
6470	u32 i;
6471	u64 *clone_sources_tmp = NULL;
6472	int clone_sources_to_rollback = 0;
6473	unsigned alloc_size;
6474	int sort_clone_roots = 0;
6475	int index;
6476
6477	if (!capable(CAP_SYS_ADMIN))
6478		return -EPERM;
6479
 
 
 
6480	/*
6481	 * The subvolume must remain read-only during send, protect against
6482	 * making it RW. This also protects against deletion.
6483	 */
6484	spin_lock(&send_root->root_item_lock);
6485	send_root->send_in_progress++;
6486	spin_unlock(&send_root->root_item_lock);
6487
6488	/*
6489	 * This is done when we lookup the root, it should already be complete
6490	 * by the time we get here.
6491	 */
6492	WARN_ON(send_root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE);
6493
6494	/*
6495	 * Userspace tools do the checks and warn the user if it's
6496	 * not RO.
6497	 */
6498	if (!btrfs_root_readonly(send_root)) {
6499		ret = -EPERM;
6500		goto out;
6501	}
6502
6503	/*
6504	 * Check that we don't overflow at later allocations, we request
6505	 * clone_sources_count + 1 items, and compare to unsigned long inside
6506	 * access_ok.
6507	 */
6508	if (arg->clone_sources_count >
6509	    ULONG_MAX / sizeof(struct clone_root) - 1) {
6510		ret = -EINVAL;
6511		goto out;
6512	}
6513
6514	if (!access_ok(VERIFY_READ, arg->clone_sources,
6515			sizeof(*arg->clone_sources) *
6516			arg->clone_sources_count)) {
6517		ret = -EFAULT;
6518		goto out;
6519	}
6520
6521	if (arg->flags & ~BTRFS_SEND_FLAG_MASK) {
6522		ret = -EINVAL;
6523		goto out;
6524	}
6525
6526	sctx = kzalloc(sizeof(struct send_ctx), GFP_KERNEL);
6527	if (!sctx) {
6528		ret = -ENOMEM;
6529		goto out;
6530	}
6531
6532	INIT_LIST_HEAD(&sctx->new_refs);
6533	INIT_LIST_HEAD(&sctx->deleted_refs);
6534	INIT_RADIX_TREE(&sctx->name_cache, GFP_KERNEL);
6535	INIT_LIST_HEAD(&sctx->name_cache_list);
6536
6537	sctx->flags = arg->flags;
6538
6539	sctx->send_filp = fget(arg->send_fd);
6540	if (!sctx->send_filp) {
6541		ret = -EBADF;
6542		goto out;
6543	}
6544
6545	sctx->send_root = send_root;
6546	/*
6547	 * Unlikely but possible, if the subvolume is marked for deletion but
6548	 * is slow to remove the directory entry, send can still be started
6549	 */
6550	if (btrfs_root_dead(sctx->send_root)) {
6551		ret = -EPERM;
6552		goto out;
6553	}
6554
6555	sctx->clone_roots_cnt = arg->clone_sources_count;
6556
6557	sctx->send_max_size = BTRFS_SEND_BUF_SIZE;
6558	sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL);
6559	if (!sctx->send_buf) {
6560		ret = -ENOMEM;
6561		goto out;
6562	}
6563
6564	sctx->read_buf = kvmalloc(BTRFS_SEND_READ_SIZE, GFP_KERNEL);
6565	if (!sctx->read_buf) {
6566		ret = -ENOMEM;
6567		goto out;
6568	}
6569
6570	sctx->pending_dir_moves = RB_ROOT;
6571	sctx->waiting_dir_moves = RB_ROOT;
6572	sctx->orphan_dirs = RB_ROOT;
6573
6574	alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1);
6575
6576	sctx->clone_roots = kzalloc(alloc_size, GFP_KERNEL);
6577	if (!sctx->clone_roots) {
6578		ret = -ENOMEM;
6579		goto out;
6580	}
6581
6582	alloc_size = arg->clone_sources_count * sizeof(*arg->clone_sources);
6583
6584	if (arg->clone_sources_count) {
6585		clone_sources_tmp = kvmalloc(alloc_size, GFP_KERNEL);
 
6586		if (!clone_sources_tmp) {
6587			ret = -ENOMEM;
6588			goto out;
6589		}
6590
6591		ret = copy_from_user(clone_sources_tmp, arg->clone_sources,
6592				alloc_size);
 
6593		if (ret) {
6594			ret = -EFAULT;
6595			goto out;
6596		}
6597
6598		for (i = 0; i < arg->clone_sources_count; i++) {
6599			key.objectid = clone_sources_tmp[i];
6600			key.type = BTRFS_ROOT_ITEM_KEY;
6601			key.offset = (u64)-1;
6602
6603			index = srcu_read_lock(&fs_info->subvol_srcu);
6604
6605			clone_root = btrfs_read_fs_root_no_name(fs_info, &key);
6606			if (IS_ERR(clone_root)) {
6607				srcu_read_unlock(&fs_info->subvol_srcu, index);
6608				ret = PTR_ERR(clone_root);
6609				goto out;
6610			}
 
6611			spin_lock(&clone_root->root_item_lock);
6612			if (!btrfs_root_readonly(clone_root) ||
6613			    btrfs_root_dead(clone_root)) {
6614				spin_unlock(&clone_root->root_item_lock);
6615				srcu_read_unlock(&fs_info->subvol_srcu, index);
6616				ret = -EPERM;
6617				goto out;
6618			}
6619			clone_root->send_in_progress++;
6620			spin_unlock(&clone_root->root_item_lock);
6621			srcu_read_unlock(&fs_info->subvol_srcu, index);
6622
6623			sctx->clone_roots[i].root = clone_root;
6624			clone_sources_to_rollback = i + 1;
6625		}
6626		kvfree(clone_sources_tmp);
6627		clone_sources_tmp = NULL;
6628	}
6629
6630	if (arg->parent_root) {
6631		key.objectid = arg->parent_root;
6632		key.type = BTRFS_ROOT_ITEM_KEY;
6633		key.offset = (u64)-1;
6634
6635		index = srcu_read_lock(&fs_info->subvol_srcu);
6636
6637		sctx->parent_root = btrfs_read_fs_root_no_name(fs_info, &key);
6638		if (IS_ERR(sctx->parent_root)) {
6639			srcu_read_unlock(&fs_info->subvol_srcu, index);
6640			ret = PTR_ERR(sctx->parent_root);
6641			goto out;
6642		}
6643
6644		spin_lock(&sctx->parent_root->root_item_lock);
6645		sctx->parent_root->send_in_progress++;
6646		if (!btrfs_root_readonly(sctx->parent_root) ||
6647				btrfs_root_dead(sctx->parent_root)) {
6648			spin_unlock(&sctx->parent_root->root_item_lock);
6649			srcu_read_unlock(&fs_info->subvol_srcu, index);
6650			ret = -EPERM;
6651			goto out;
6652		}
6653		spin_unlock(&sctx->parent_root->root_item_lock);
6654
6655		srcu_read_unlock(&fs_info->subvol_srcu, index);
6656	}
6657
6658	/*
6659	 * Clones from send_root are allowed, but only if the clone source
6660	 * is behind the current send position. This is checked while searching
6661	 * for possible clone sources.
6662	 */
6663	sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root;
6664
6665	/* We do a bsearch later */
6666	sort(sctx->clone_roots, sctx->clone_roots_cnt,
6667			sizeof(*sctx->clone_roots), __clone_root_cmp_sort,
6668			NULL);
6669	sort_clone_roots = 1;
6670
6671	ret = ensure_commit_roots_uptodate(sctx);
6672	if (ret)
6673		goto out;
6674
6675	current->journal_info = BTRFS_SEND_TRANS_STUB;
6676	ret = send_subvol(sctx);
6677	current->journal_info = NULL;
6678	if (ret < 0)
6679		goto out;
6680
6681	if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_END_CMD)) {
6682		ret = begin_cmd(sctx, BTRFS_SEND_C_END);
6683		if (ret < 0)
6684			goto out;
6685		ret = send_cmd(sctx);
6686		if (ret < 0)
6687			goto out;
6688	}
6689
6690out:
6691	WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->pending_dir_moves));
6692	while (sctx && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)) {
6693		struct rb_node *n;
6694		struct pending_dir_move *pm;
6695
6696		n = rb_first(&sctx->pending_dir_moves);
6697		pm = rb_entry(n, struct pending_dir_move, node);
6698		while (!list_empty(&pm->list)) {
6699			struct pending_dir_move *pm2;
6700
6701			pm2 = list_first_entry(&pm->list,
6702					       struct pending_dir_move, list);
6703			free_pending_move(sctx, pm2);
6704		}
6705		free_pending_move(sctx, pm);
6706	}
6707
6708	WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves));
6709	while (sctx && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) {
6710		struct rb_node *n;
6711		struct waiting_dir_move *dm;
6712
6713		n = rb_first(&sctx->waiting_dir_moves);
6714		dm = rb_entry(n, struct waiting_dir_move, node);
6715		rb_erase(&dm->node, &sctx->waiting_dir_moves);
6716		kfree(dm);
6717	}
6718
6719	WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->orphan_dirs));
6720	while (sctx && !RB_EMPTY_ROOT(&sctx->orphan_dirs)) {
6721		struct rb_node *n;
6722		struct orphan_dir_info *odi;
6723
6724		n = rb_first(&sctx->orphan_dirs);
6725		odi = rb_entry(n, struct orphan_dir_info, node);
6726		free_orphan_dir_info(sctx, odi);
6727	}
6728
6729	if (sort_clone_roots) {
6730		for (i = 0; i < sctx->clone_roots_cnt; i++)
6731			btrfs_root_dec_send_in_progress(
6732					sctx->clone_roots[i].root);
6733	} else {
6734		for (i = 0; sctx && i < clone_sources_to_rollback; i++)
6735			btrfs_root_dec_send_in_progress(
6736					sctx->clone_roots[i].root);
6737
6738		btrfs_root_dec_send_in_progress(send_root);
6739	}
6740	if (sctx && !IS_ERR_OR_NULL(sctx->parent_root))
6741		btrfs_root_dec_send_in_progress(sctx->parent_root);
6742
6743	kvfree(clone_sources_tmp);
 
6744
6745	if (sctx) {
6746		if (sctx->send_filp)
6747			fput(sctx->send_filp);
6748
6749		kvfree(sctx->clone_roots);
6750		kvfree(sctx->send_buf);
6751		kvfree(sctx->read_buf);
6752
6753		name_cache_free(sctx);
6754
6755		kfree(sctx);
6756	}
6757
6758	return ret;
6759}