send.c 103.4 KB
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/*
 * Copyright (C) 2012 Alexander Block.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/bsearch.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/sort.h>
#include <linux/mount.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/radix-tree.h>
#include <linux/crc32c.h>
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#include <linux/vmalloc.h>
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#include "send.h"
#include "backref.h"
#include "locking.h"
#include "disk-io.h"
#include "btrfs_inode.h"
#include "transaction.h"

static int g_verbose = 0;

#define verbose_printk(...) if (g_verbose) printk(__VA_ARGS__)

/*
 * A fs_path is a helper to dynamically build path names with unknown size.
 * It reallocates the internal buffer on demand.
 * It allows fast adding of path elements on the right side (normal path) and
 * fast adding to the left side (reversed path). A reversed path can also be
 * unreversed if needed.
 */
struct fs_path {
	union {
		struct {
			char *start;
			char *end;
			char *prepared;

			char *buf;
			int buf_len;
			int reversed:1;
			int virtual_mem:1;
			char inline_buf[];
		};
		char pad[PAGE_SIZE];
	};
};
#define FS_PATH_INLINE_SIZE \
	(sizeof(struct fs_path) - offsetof(struct fs_path, inline_buf))


/* reused for each extent */
struct clone_root {
	struct btrfs_root *root;
	u64 ino;
	u64 offset;

	u64 found_refs;
};

#define SEND_CTX_MAX_NAME_CACHE_SIZE 128
#define SEND_CTX_NAME_CACHE_CLEAN_SIZE (SEND_CTX_MAX_NAME_CACHE_SIZE * 2)

struct send_ctx {
	struct file *send_filp;
	loff_t send_off;
	char *send_buf;
	u32 send_size;
	u32 send_max_size;
	u64 total_send_size;
	u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];

	struct vfsmount *mnt;

	struct btrfs_root *send_root;
	struct btrfs_root *parent_root;
	struct clone_root *clone_roots;
	int clone_roots_cnt;

	/* current state of the compare_tree call */
	struct btrfs_path *left_path;
	struct btrfs_path *right_path;
	struct btrfs_key *cmp_key;

	/*
	 * infos of the currently processed inode. In case of deleted inodes,
	 * these are the values from the deleted inode.
	 */
	u64 cur_ino;
	u64 cur_inode_gen;
	int cur_inode_new;
	int cur_inode_new_gen;
	int cur_inode_deleted;
	u64 cur_inode_size;
	u64 cur_inode_mode;

	u64 send_progress;

	struct list_head new_refs;
	struct list_head deleted_refs;

	struct radix_tree_root name_cache;
	struct list_head name_cache_list;
	int name_cache_size;

	struct file *cur_inode_filp;
	char *read_buf;
};

struct name_cache_entry {
	struct list_head list;
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	/*
	 * radix_tree has only 32bit entries but we need to handle 64bit inums.
	 * We use the lower 32bit of the 64bit inum to store it in the tree. If
	 * more then one inum would fall into the same entry, we use radix_list
	 * to store the additional entries. radix_list is also used to store
	 * entries where two entries have the same inum but different
	 * generations.
	 */
	struct list_head radix_list;
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	u64 ino;
	u64 gen;
	u64 parent_ino;
	u64 parent_gen;
	int ret;
	int need_later_update;
	int name_len;
	char name[];
};

static void fs_path_reset(struct fs_path *p)
{
	if (p->reversed) {
		p->start = p->buf + p->buf_len - 1;
		p->end = p->start;
		*p->start = 0;
	} else {
		p->start = p->buf;
		p->end = p->start;
		*p->start = 0;
	}
}

static struct fs_path *fs_path_alloc(struct send_ctx *sctx)
{
	struct fs_path *p;

	p = kmalloc(sizeof(*p), GFP_NOFS);
	if (!p)
		return NULL;
	p->reversed = 0;
	p->virtual_mem = 0;
	p->buf = p->inline_buf;
	p->buf_len = FS_PATH_INLINE_SIZE;
	fs_path_reset(p);
	return p;
}

static struct fs_path *fs_path_alloc_reversed(struct send_ctx *sctx)
{
	struct fs_path *p;

	p = fs_path_alloc(sctx);
	if (!p)
		return NULL;
	p->reversed = 1;
	fs_path_reset(p);
	return p;
}

static void fs_path_free(struct send_ctx *sctx, struct fs_path *p)
{
	if (!p)
		return;
	if (p->buf != p->inline_buf) {
		if (p->virtual_mem)
			vfree(p->buf);
		else
			kfree(p->buf);
	}
	kfree(p);
}

static int fs_path_len(struct fs_path *p)
{
	return p->end - p->start;
}

static int fs_path_ensure_buf(struct fs_path *p, int len)
{
	char *tmp_buf;
	int path_len;
	int old_buf_len;

	len++;

	if (p->buf_len >= len)
		return 0;

	path_len = p->end - p->start;
	old_buf_len = p->buf_len;
	len = PAGE_ALIGN(len);

	if (p->buf == p->inline_buf) {
		tmp_buf = kmalloc(len, GFP_NOFS);
		if (!tmp_buf) {
			tmp_buf = vmalloc(len);
			if (!tmp_buf)
				return -ENOMEM;
			p->virtual_mem = 1;
		}
		memcpy(tmp_buf, p->buf, p->buf_len);
		p->buf = tmp_buf;
		p->buf_len = len;
	} else {
		if (p->virtual_mem) {
			tmp_buf = vmalloc(len);
			if (!tmp_buf)
				return -ENOMEM;
			memcpy(tmp_buf, p->buf, p->buf_len);
			vfree(p->buf);
		} else {
			tmp_buf = krealloc(p->buf, len, GFP_NOFS);
			if (!tmp_buf) {
				tmp_buf = vmalloc(len);
				if (!tmp_buf)
					return -ENOMEM;
				memcpy(tmp_buf, p->buf, p->buf_len);
				kfree(p->buf);
				p->virtual_mem = 1;
			}
		}
		p->buf = tmp_buf;
		p->buf_len = len;
	}
	if (p->reversed) {
		tmp_buf = p->buf + old_buf_len - path_len - 1;
		p->end = p->buf + p->buf_len - 1;
		p->start = p->end - path_len;
		memmove(p->start, tmp_buf, path_len + 1);
	} else {
		p->start = p->buf;
		p->end = p->start + path_len;
	}
	return 0;
}

static int fs_path_prepare_for_add(struct fs_path *p, int name_len)
{
	int ret;
	int new_len;

	new_len = p->end - p->start + name_len;
	if (p->start != p->end)
		new_len++;
	ret = fs_path_ensure_buf(p, new_len);
	if (ret < 0)
		goto out;

	if (p->reversed) {
		if (p->start != p->end)
			*--p->start = '/';
		p->start -= name_len;
		p->prepared = p->start;
	} else {
		if (p->start != p->end)
			*p->end++ = '/';
		p->prepared = p->end;
		p->end += name_len;
		*p->end = 0;
	}

out:
	return ret;
}

static int fs_path_add(struct fs_path *p, const char *name, int name_len)
{
	int ret;

	ret = fs_path_prepare_for_add(p, name_len);
	if (ret < 0)
		goto out;
	memcpy(p->prepared, name, name_len);
	p->prepared = NULL;

out:
	return ret;
}

static int fs_path_add_path(struct fs_path *p, struct fs_path *p2)
{
	int ret;

	ret = fs_path_prepare_for_add(p, p2->end - p2->start);
	if (ret < 0)
		goto out;
	memcpy(p->prepared, p2->start, p2->end - p2->start);
	p->prepared = NULL;

out:
	return ret;
}

static int fs_path_add_from_extent_buffer(struct fs_path *p,
					  struct extent_buffer *eb,
					  unsigned long off, int len)
{
	int ret;

	ret = fs_path_prepare_for_add(p, len);
	if (ret < 0)
		goto out;

	read_extent_buffer(eb, p->prepared, off, len);
	p->prepared = NULL;

out:
	return ret;
}

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#if 0
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static void fs_path_remove(struct fs_path *p)
{
	BUG_ON(p->reversed);
	while (p->start != p->end && *p->end != '/')
		p->end--;
	*p->end = 0;
}
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#endif
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static int fs_path_copy(struct fs_path *p, struct fs_path *from)
{
	int ret;

	p->reversed = from->reversed;
	fs_path_reset(p);

	ret = fs_path_add_path(p, from);

	return ret;
}


static void fs_path_unreverse(struct fs_path *p)
{
	char *tmp;
	int len;

	if (!p->reversed)
		return;

	tmp = p->start;
	len = p->end - p->start;
	p->start = p->buf;
	p->end = p->start + len;
	memmove(p->start, tmp, len + 1);
	p->reversed = 0;
}

static struct btrfs_path *alloc_path_for_send(void)
{
	struct btrfs_path *path;

	path = btrfs_alloc_path();
	if (!path)
		return NULL;
	path->search_commit_root = 1;
	path->skip_locking = 1;
	return path;
}

static int write_buf(struct send_ctx *sctx, const void *buf, u32 len)
{
	int ret;
	mm_segment_t old_fs;
	u32 pos = 0;

	old_fs = get_fs();
	set_fs(KERNEL_DS);

	while (pos < len) {
		ret = vfs_write(sctx->send_filp, (char *)buf + pos, len - pos,
				&sctx->send_off);
		/* TODO handle that correctly */
		/*if (ret == -ERESTARTSYS) {
			continue;
		}*/
		if (ret < 0)
			goto out;
		if (ret == 0) {
			ret = -EIO;
			goto out;
		}
		pos += ret;
	}

	ret = 0;

out:
	set_fs(old_fs);
	return ret;
}

static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len)
{
	struct btrfs_tlv_header *hdr;
	int total_len = sizeof(*hdr) + len;
	int left = sctx->send_max_size - sctx->send_size;

	if (unlikely(left < total_len))
		return -EOVERFLOW;

	hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size);
	hdr->tlv_type = cpu_to_le16(attr);
	hdr->tlv_len = cpu_to_le16(len);
	memcpy(hdr + 1, data, len);
	sctx->send_size += total_len;

	return 0;
}

#if 0
static int tlv_put_u8(struct send_ctx *sctx, u16 attr, u8 value)
{
	return tlv_put(sctx, attr, &value, sizeof(value));
}

static int tlv_put_u16(struct send_ctx *sctx, u16 attr, u16 value)
{
	__le16 tmp = cpu_to_le16(value);
	return tlv_put(sctx, attr, &tmp, sizeof(tmp));
}

static int tlv_put_u32(struct send_ctx *sctx, u16 attr, u32 value)
{
	__le32 tmp = cpu_to_le32(value);
	return tlv_put(sctx, attr, &tmp, sizeof(tmp));
}
#endif

static int tlv_put_u64(struct send_ctx *sctx, u16 attr, u64 value)
{
	__le64 tmp = cpu_to_le64(value);
	return tlv_put(sctx, attr, &tmp, sizeof(tmp));
}

static int tlv_put_string(struct send_ctx *sctx, u16 attr,
			  const char *str, int len)
{
	if (len == -1)
		len = strlen(str);
	return tlv_put(sctx, attr, str, len);
}

static int tlv_put_uuid(struct send_ctx *sctx, u16 attr,
			const u8 *uuid)
{
	return tlv_put(sctx, attr, uuid, BTRFS_UUID_SIZE);
}

#if 0
static int tlv_put_timespec(struct send_ctx *sctx, u16 attr,
			    struct timespec *ts)
{
	struct btrfs_timespec bts;
	bts.sec = cpu_to_le64(ts->tv_sec);
	bts.nsec = cpu_to_le32(ts->tv_nsec);
	return tlv_put(sctx, attr, &bts, sizeof(bts));
}
#endif

static int tlv_put_btrfs_timespec(struct send_ctx *sctx, u16 attr,
				  struct extent_buffer *eb,
				  struct btrfs_timespec *ts)
{
	struct btrfs_timespec bts;
	read_extent_buffer(eb, &bts, (unsigned long)ts, sizeof(bts));
	return tlv_put(sctx, attr, &bts, sizeof(bts));
}


#define TLV_PUT(sctx, attrtype, attrlen, data) \
	do { \
		ret = tlv_put(sctx, attrtype, attrlen, data); \
		if (ret < 0) \
			goto tlv_put_failure; \
	} while (0)

#define TLV_PUT_INT(sctx, attrtype, bits, value) \
	do { \
		ret = tlv_put_u##bits(sctx, attrtype, value); \
		if (ret < 0) \
			goto tlv_put_failure; \
	} while (0)

#define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data)
#define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data)
#define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data)
#define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data)
#define TLV_PUT_STRING(sctx, attrtype, str, len) \
	do { \
		ret = tlv_put_string(sctx, attrtype, str, len); \
		if (ret < 0) \
			goto tlv_put_failure; \
	} while (0)
#define TLV_PUT_PATH(sctx, attrtype, p) \
	do { \
		ret = tlv_put_string(sctx, attrtype, p->start, \
			p->end - p->start); \
		if (ret < 0) \
			goto tlv_put_failure; \
	} while(0)
#define TLV_PUT_UUID(sctx, attrtype, uuid) \
	do { \
		ret = tlv_put_uuid(sctx, attrtype, uuid); \
		if (ret < 0) \
			goto tlv_put_failure; \
	} while (0)
#define TLV_PUT_TIMESPEC(sctx, attrtype, ts) \
	do { \
		ret = tlv_put_timespec(sctx, attrtype, ts); \
		if (ret < 0) \
			goto tlv_put_failure; \
	} while (0)
#define TLV_PUT_BTRFS_TIMESPEC(sctx, attrtype, eb, ts) \
	do { \
		ret = tlv_put_btrfs_timespec(sctx, attrtype, eb, ts); \
		if (ret < 0) \
			goto tlv_put_failure; \
	} while (0)

static int send_header(struct send_ctx *sctx)
{
	struct btrfs_stream_header hdr;

	strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
	hdr.version = cpu_to_le32(BTRFS_SEND_STREAM_VERSION);

	return write_buf(sctx, &hdr, sizeof(hdr));
}

/*
 * For each command/item we want to send to userspace, we call this function.
 */
static int begin_cmd(struct send_ctx *sctx, int cmd)
{
	struct btrfs_cmd_header *hdr;

	if (!sctx->send_buf) {
		WARN_ON(1);
		return -EINVAL;
	}

	BUG_ON(sctx->send_size);

	sctx->send_size += sizeof(*hdr);
	hdr = (struct btrfs_cmd_header *)sctx->send_buf;
	hdr->cmd = cpu_to_le16(cmd);

	return 0;
}

static int send_cmd(struct send_ctx *sctx)
{
	int ret;
	struct btrfs_cmd_header *hdr;
	u32 crc;

	hdr = (struct btrfs_cmd_header *)sctx->send_buf;
	hdr->len = cpu_to_le32(sctx->send_size - sizeof(*hdr));
	hdr->crc = 0;

	crc = crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
	hdr->crc = cpu_to_le32(crc);

	ret = write_buf(sctx, sctx->send_buf, sctx->send_size);

	sctx->total_send_size += sctx->send_size;
	sctx->cmd_send_size[le16_to_cpu(hdr->cmd)] += sctx->send_size;
	sctx->send_size = 0;

	return ret;
}

/*
 * Sends a move instruction to user space
 */
static int send_rename(struct send_ctx *sctx,
		     struct fs_path *from, struct fs_path *to)
{
	int ret;

verbose_printk("btrfs: send_rename %s -> %s\n", from->start, to->start);

	ret = begin_cmd(sctx, BTRFS_SEND_C_RENAME);
	if (ret < 0)
		goto out;

	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, from);
	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_TO, to);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	return ret;
}

/*
 * Sends a link instruction to user space
 */
static int send_link(struct send_ctx *sctx,
		     struct fs_path *path, struct fs_path *lnk)
{
	int ret;

verbose_printk("btrfs: send_link %s -> %s\n", path->start, lnk->start);

	ret = begin_cmd(sctx, BTRFS_SEND_C_LINK);
	if (ret < 0)
		goto out;

	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, lnk);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	return ret;
}

/*
 * Sends an unlink instruction to user space
 */
static int send_unlink(struct send_ctx *sctx, struct fs_path *path)
{
	int ret;

verbose_printk("btrfs: send_unlink %s\n", path->start);

	ret = begin_cmd(sctx, BTRFS_SEND_C_UNLINK);
	if (ret < 0)
		goto out;

	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	return ret;
}

/*
 * Sends a rmdir instruction to user space
 */
static int send_rmdir(struct send_ctx *sctx, struct fs_path *path)
{
	int ret;

verbose_printk("btrfs: send_rmdir %s\n", path->start);

	ret = begin_cmd(sctx, BTRFS_SEND_C_RMDIR);
	if (ret < 0)
		goto out;

	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	return ret;
}

/*
 * Helper function to retrieve some fields from an inode item.
 */
static int get_inode_info(struct btrfs_root *root,
			  u64 ino, u64 *size, u64 *gen,
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			  u64 *mode, u64 *uid, u64 *gid,
			  u64 *rdev)
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{
	int ret;
	struct btrfs_inode_item *ii;
	struct btrfs_key key;
	struct btrfs_path *path;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	key.objectid = ino;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;
	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		goto out;
	if (ret) {
		ret = -ENOENT;
		goto out;
	}

	ii = btrfs_item_ptr(path->nodes[0], path->slots[0],
			struct btrfs_inode_item);
	if (size)
		*size = btrfs_inode_size(path->nodes[0], ii);
	if (gen)
		*gen = btrfs_inode_generation(path->nodes[0], ii);
	if (mode)
		*mode = btrfs_inode_mode(path->nodes[0], ii);
	if (uid)
		*uid = btrfs_inode_uid(path->nodes[0], ii);
	if (gid)
		*gid = btrfs_inode_gid(path->nodes[0], ii);
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	if (rdev)
		*rdev = btrfs_inode_rdev(path->nodes[0], ii);
736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032

out:
	btrfs_free_path(path);
	return ret;
}

typedef int (*iterate_inode_ref_t)(int num, u64 dir, int index,
				   struct fs_path *p,
				   void *ctx);

/*
 * Helper function to iterate the entries in ONE btrfs_inode_ref.
 * The iterate callback may return a non zero value to stop iteration. This can
 * be a negative value for error codes or 1 to simply stop it.
 *
 * path must point to the INODE_REF when called.
 */
static int iterate_inode_ref(struct send_ctx *sctx,
			     struct btrfs_root *root, struct btrfs_path *path,
			     struct btrfs_key *found_key, int resolve,
			     iterate_inode_ref_t iterate, void *ctx)
{
	struct extent_buffer *eb;
	struct btrfs_item *item;
	struct btrfs_inode_ref *iref;
	struct btrfs_path *tmp_path;
	struct fs_path *p;
	u32 cur;
	u32 len;
	u32 total;
	int slot;
	u32 name_len;
	char *start;
	int ret = 0;
	int num;
	int index;

	p = fs_path_alloc_reversed(sctx);
	if (!p)
		return -ENOMEM;

	tmp_path = alloc_path_for_send();
	if (!tmp_path) {
		fs_path_free(sctx, p);
		return -ENOMEM;
	}

	eb = path->nodes[0];
	slot = path->slots[0];
	item = btrfs_item_nr(eb, slot);
	iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
	cur = 0;
	len = 0;
	total = btrfs_item_size(eb, item);

	num = 0;
	while (cur < total) {
		fs_path_reset(p);

		name_len = btrfs_inode_ref_name_len(eb, iref);
		index = btrfs_inode_ref_index(eb, iref);
		if (resolve) {
			start = btrfs_iref_to_path(root, tmp_path, iref, eb,
						found_key->offset, p->buf,
						p->buf_len);
			if (IS_ERR(start)) {
				ret = PTR_ERR(start);
				goto out;
			}
			if (start < p->buf) {
				/* overflow , try again with larger buffer */
				ret = fs_path_ensure_buf(p,
						p->buf_len + p->buf - start);
				if (ret < 0)
					goto out;
				start = btrfs_iref_to_path(root, tmp_path, iref,
						eb, found_key->offset, p->buf,
						p->buf_len);
				if (IS_ERR(start)) {
					ret = PTR_ERR(start);
					goto out;
				}
				BUG_ON(start < p->buf);
			}
			p->start = start;
		} else {
			ret = fs_path_add_from_extent_buffer(p, eb,
					(unsigned long)(iref + 1), name_len);
			if (ret < 0)
				goto out;
		}


		len = sizeof(*iref) + name_len;
		iref = (struct btrfs_inode_ref *)((char *)iref + len);
		cur += len;

		ret = iterate(num, found_key->offset, index, p, ctx);
		if (ret)
			goto out;

		num++;
	}

out:
	btrfs_free_path(tmp_path);
	fs_path_free(sctx, p);
	return ret;
}

typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key,
				  const char *name, int name_len,
				  const char *data, int data_len,
				  u8 type, void *ctx);

/*
 * Helper function to iterate the entries in ONE btrfs_dir_item.
 * The iterate callback may return a non zero value to stop iteration. This can
 * be a negative value for error codes or 1 to simply stop it.
 *
 * path must point to the dir item when called.
 */
static int iterate_dir_item(struct send_ctx *sctx,
			    struct btrfs_root *root, struct btrfs_path *path,
			    struct btrfs_key *found_key,
			    iterate_dir_item_t iterate, void *ctx)
{
	int ret = 0;
	struct extent_buffer *eb;
	struct btrfs_item *item;
	struct btrfs_dir_item *di;
	struct btrfs_key di_key;
	char *buf = NULL;
	char *buf2 = NULL;
	int buf_len;
	int buf_virtual = 0;
	u32 name_len;
	u32 data_len;
	u32 cur;
	u32 len;
	u32 total;
	int slot;
	int num;
	u8 type;

	buf_len = PAGE_SIZE;
	buf = kmalloc(buf_len, GFP_NOFS);
	if (!buf) {
		ret = -ENOMEM;
		goto out;
	}

	eb = path->nodes[0];
	slot = path->slots[0];
	item = btrfs_item_nr(eb, slot);
	di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
	cur = 0;
	len = 0;
	total = btrfs_item_size(eb, item);

	num = 0;
	while (cur < total) {
		name_len = btrfs_dir_name_len(eb, di);
		data_len = btrfs_dir_data_len(eb, di);
		type = btrfs_dir_type(eb, di);
		btrfs_dir_item_key_to_cpu(eb, di, &di_key);

		if (name_len + data_len > buf_len) {
			buf_len = PAGE_ALIGN(name_len + data_len);
			if (buf_virtual) {
				buf2 = vmalloc(buf_len);
				if (!buf2) {
					ret = -ENOMEM;
					goto out;
				}
				vfree(buf);
			} else {
				buf2 = krealloc(buf, buf_len, GFP_NOFS);
				if (!buf2) {
					buf2 = vmalloc(buf_len);
					if (!buf2) {
						ret = -ENOMEM;
						goto out;
					}
					kfree(buf);
					buf_virtual = 1;
				}
			}

			buf = buf2;
			buf2 = NULL;
		}

		read_extent_buffer(eb, buf, (unsigned long)(di + 1),
				name_len + data_len);

		len = sizeof(*di) + name_len + data_len;
		di = (struct btrfs_dir_item *)((char *)di + len);
		cur += len;

		ret = iterate(num, &di_key, buf, name_len, buf + name_len,
				data_len, type, ctx);
		if (ret < 0)
			goto out;
		if (ret) {
			ret = 0;
			goto out;
		}

		num++;
	}

out:
	if (buf_virtual)
		vfree(buf);
	else
		kfree(buf);
	return ret;
}

static int __copy_first_ref(int num, u64 dir, int index,
			    struct fs_path *p, void *ctx)
{
	int ret;
	struct fs_path *pt = ctx;

	ret = fs_path_copy(pt, p);
	if (ret < 0)
		return ret;

	/* we want the first only */
	return 1;
}

/*
 * Retrieve the first path of an inode. If an inode has more then one
 * ref/hardlink, this is ignored.
 */
static int get_inode_path(struct send_ctx *sctx, struct btrfs_root *root,
			  u64 ino, struct fs_path *path)
{
	int ret;
	struct btrfs_key key, found_key;
	struct btrfs_path *p;

	p = alloc_path_for_send();
	if (!p)
		return -ENOMEM;

	fs_path_reset(path);

	key.objectid = ino;
	key.type = BTRFS_INODE_REF_KEY;
	key.offset = 0;

	ret = btrfs_search_slot_for_read(root, &key, p, 1, 0);
	if (ret < 0)
		goto out;
	if (ret) {
		ret = 1;
		goto out;
	}
	btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]);
	if (found_key.objectid != ino ||
		found_key.type != BTRFS_INODE_REF_KEY) {
		ret = -ENOENT;
		goto out;
	}

	ret = iterate_inode_ref(sctx, root, p, &found_key, 1,
			__copy_first_ref, path);
	if (ret < 0)
		goto out;
	ret = 0;

out:
	btrfs_free_path(p);
	return ret;
}

struct backref_ctx {
	struct send_ctx *sctx;

	/* number of total found references */
	u64 found;

	/*
	 * used for clones found in send_root. clones found behind cur_objectid
	 * and cur_offset are not considered as allowed clones.
	 */
	u64 cur_objectid;
	u64 cur_offset;

	/* may be truncated in case it's the last extent in a file */
	u64 extent_len;

	/* Just to check for bugs in backref resolving */
1033
	int found_itself;
1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061
};

static int __clone_root_cmp_bsearch(const void *key, const void *elt)
{
	u64 root = (u64)key;
	struct clone_root *cr = (struct clone_root *)elt;

	if (root < cr->root->objectid)
		return -1;
	if (root > cr->root->objectid)
		return 1;
	return 0;
}

static int __clone_root_cmp_sort(const void *e1, const void *e2)
{
	struct clone_root *cr1 = (struct clone_root *)e1;
	struct clone_root *cr2 = (struct clone_root *)e2;

	if (cr1->root->objectid < cr2->root->objectid)
		return -1;
	if (cr1->root->objectid > cr2->root->objectid)
		return 1;
	return 0;
}

/*
 * Called for every backref that is found for the current extent.
1062
 * Results are collected in sctx->clone_roots->ino/offset/found_refs
1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081
 */
static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_)
{
	struct backref_ctx *bctx = ctx_;
	struct clone_root *found;
	int ret;
	u64 i_size;

	/* First check if the root is in the list of accepted clone sources */
	found = bsearch((void *)root, bctx->sctx->clone_roots,
			bctx->sctx->clone_roots_cnt,
			sizeof(struct clone_root),
			__clone_root_cmp_bsearch);
	if (!found)
		return 0;

	if (found->root == bctx->sctx->send_root &&
	    ino == bctx->cur_objectid &&
	    offset == bctx->cur_offset) {
1082
		bctx->found_itself = 1;
1083 1084 1085
	}

	/*
1086
	 * There are inodes that have extents that lie behind its i_size. Don't
1087 1088
	 * accept clones from these extents.
	 */
1089 1090
	ret = get_inode_info(found->root, ino, &i_size, NULL, NULL, NULL, NULL,
			NULL);
1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109
	if (ret < 0)
		return ret;

	if (offset + bctx->extent_len > i_size)
		return 0;

	/*
	 * Make sure we don't consider clones from send_root that are
	 * behind the current inode/offset.
	 */
	if (found->root == bctx->sctx->send_root) {
		/*
		 * TODO for the moment we don't accept clones from the inode
		 * that is currently send. We may change this when
		 * BTRFS_IOC_CLONE_RANGE supports cloning from and to the same
		 * file.
		 */
		if (ino >= bctx->cur_objectid)
			return 0;
1110 1111 1112 1113
#if 0
		if (ino > bctx->cur_objectid)
			return 0;
		if (offset + bctx->extent_len > bctx->cur_offset)
1114
			return 0;
1115
#endif
1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134
	}

	bctx->found++;
	found->found_refs++;
	if (ino < found->ino) {
		found->ino = ino;
		found->offset = offset;
	} else if (found->ino == ino) {
		/*
		 * same extent found more then once in the same file.
		 */
		if (found->offset > offset + bctx->extent_len)
			found->offset = offset;
	}

	return 0;
}

/*
1135 1136 1137 1138 1139 1140
 * Given an inode, offset and extent item, it finds a good clone for a clone
 * instruction. Returns -ENOENT when none could be found. The function makes
 * sure that the returned clone is usable at the point where sending is at the
 * moment. This means, that no clones are accepted which lie behind the current
 * inode+offset.
 *
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
 * path must point to the extent item when called.
 */
static int find_extent_clone(struct send_ctx *sctx,
			     struct btrfs_path *path,
			     u64 ino, u64 data_offset,
			     u64 ino_size,
			     struct clone_root **found)
{
	int ret;
	int extent_type;
	u64 logical;
1152
	u64 disk_byte;
1153 1154 1155 1156
	u64 num_bytes;
	u64 extent_item_pos;
	struct btrfs_file_extent_item *fi;
	struct extent_buffer *eb = path->nodes[0];
1157
	struct backref_ctx *backref_ctx = NULL;
1158 1159 1160
	struct clone_root *cur_clone_root;
	struct btrfs_key found_key;
	struct btrfs_path *tmp_path;
1161
	int compressed;
1162 1163 1164 1165 1166 1167
	u32 i;

	tmp_path = alloc_path_for_send();
	if (!tmp_path)
		return -ENOMEM;

1168 1169 1170 1171 1172 1173
	backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_NOFS);
	if (!backref_ctx) {
		ret = -ENOMEM;
		goto out;
	}

1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190
	if (data_offset >= ino_size) {
		/*
		 * There may be extents that lie behind the file's size.
		 * I at least had this in combination with snapshotting while
		 * writing large files.
		 */
		ret = 0;
		goto out;
	}

	fi = btrfs_item_ptr(eb, path->slots[0],
			struct btrfs_file_extent_item);
	extent_type = btrfs_file_extent_type(eb, fi);
	if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
		ret = -ENOENT;
		goto out;
	}
1191
	compressed = btrfs_file_extent_compression(eb, fi);
1192 1193

	num_bytes = btrfs_file_extent_num_bytes(eb, fi);
1194 1195
	disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
	if (disk_byte == 0) {
1196 1197 1198
		ret = -ENOENT;
		goto out;
	}
1199
	logical = disk_byte + btrfs_file_extent_offset(eb, fi);
1200 1201

	ret = extent_from_logical(sctx->send_root->fs_info,
1202
			disk_byte, tmp_path, &found_key);
1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221
	btrfs_release_path(tmp_path);

	if (ret < 0)
		goto out;
	if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
		ret = -EIO;
		goto out;
	}

	/*
	 * Setup the clone roots.
	 */
	for (i = 0; i < sctx->clone_roots_cnt; i++) {
		cur_clone_root = sctx->clone_roots + i;
		cur_clone_root->ino = (u64)-1;
		cur_clone_root->offset = 0;
		cur_clone_root->found_refs = 0;
	}

1222 1223 1224 1225 1226 1227
	backref_ctx->sctx = sctx;
	backref_ctx->found = 0;
	backref_ctx->cur_objectid = ino;
	backref_ctx->cur_offset = data_offset;
	backref_ctx->found_itself = 0;
	backref_ctx->extent_len = num_bytes;
1228 1229 1230 1231 1232 1233 1234

	/*
	 * The last extent of a file may be too large due to page alignment.
	 * We need to adjust extent_len in this case so that the checks in
	 * __iterate_backrefs work.
	 */
	if (data_offset + num_bytes >= ino_size)
1235
		backref_ctx->extent_len = ino_size - data_offset;
1236 1237 1238 1239

	/*
	 * Now collect all backrefs.
	 */
1240 1241 1242 1243 1244
	if (compressed == BTRFS_COMPRESS_NONE)
		extent_item_pos = logical - found_key.objectid;
	else
		extent_item_pos = 0;

1245 1246 1247
	extent_item_pos = logical - found_key.objectid;
	ret = iterate_extent_inodes(sctx->send_root->fs_info,
					found_key.objectid, extent_item_pos, 1,
1248
					__iterate_backrefs, backref_ctx);
1249

1250 1251 1252
	if (ret < 0)
		goto out;

1253
	if (!backref_ctx->found_itself) {
1254 1255 1256 1257
		/* found a bug in backref code? */
		ret = -EIO;
		printk(KERN_ERR "btrfs: ERROR did not find backref in "
				"send_root. inode=%llu, offset=%llu, "
1258 1259
				"disk_byte=%llu found extent=%llu\n",
				ino, data_offset, disk_byte, found_key.objectid);
1260 1261 1262 1263 1264 1265 1266 1267
		goto out;
	}

verbose_printk(KERN_DEBUG "btrfs: find_extent_clone: data_offset=%llu, "
		"ino=%llu, "
		"num_bytes=%llu, logical=%llu\n",
		data_offset, ino, num_bytes, logical);

1268
	if (!backref_ctx->found)
1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291
		verbose_printk("btrfs:    no clones found\n");

	cur_clone_root = NULL;
	for (i = 0; i < sctx->clone_roots_cnt; i++) {
		if (sctx->clone_roots[i].found_refs) {
			if (!cur_clone_root)
				cur_clone_root = sctx->clone_roots + i;
			else if (sctx->clone_roots[i].root == sctx->send_root)
				/* prefer clones from send_root over others */
				cur_clone_root = sctx->clone_roots + i;
		}

	}

	if (cur_clone_root) {
		*found = cur_clone_root;
		ret = 0;
	} else {
		ret = -ENOENT;
	}

out:
	btrfs_free_path(tmp_path);
1292
	kfree(backref_ctx);
1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427
	return ret;
}

static int read_symlink(struct send_ctx *sctx,
			struct btrfs_root *root,
			u64 ino,
			struct fs_path *dest)
{
	int ret;
	struct btrfs_path *path;
	struct btrfs_key key;
	struct btrfs_file_extent_item *ei;
	u8 type;
	u8 compression;
	unsigned long off;
	int len;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	key.objectid = ino;
	key.type = BTRFS_EXTENT_DATA_KEY;
	key.offset = 0;
	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		goto out;
	BUG_ON(ret);

	ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
			struct btrfs_file_extent_item);
	type = btrfs_file_extent_type(path->nodes[0], ei);
	compression = btrfs_file_extent_compression(path->nodes[0], ei);
	BUG_ON(type != BTRFS_FILE_EXTENT_INLINE);
	BUG_ON(compression);

	off = btrfs_file_extent_inline_start(ei);
	len = btrfs_file_extent_inline_len(path->nodes[0], ei);

	ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len);

out:
	btrfs_free_path(path);
	return ret;
}

/*
 * Helper function to generate a file name that is unique in the root of
 * send_root and parent_root. This is used to generate names for orphan inodes.
 */
static int gen_unique_name(struct send_ctx *sctx,
			   u64 ino, u64 gen,
			   struct fs_path *dest)
{
	int ret = 0;
	struct btrfs_path *path;
	struct btrfs_dir_item *di;
	char tmp[64];
	int len;
	u64 idx = 0;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	while (1) {
		len = snprintf(tmp, sizeof(tmp) - 1, "o%llu-%llu-%llu",
				ino, gen, idx);
		if (len >= sizeof(tmp)) {
			/* should really not happen */
			ret = -EOVERFLOW;
			goto out;
		}

		di = btrfs_lookup_dir_item(NULL, sctx->send_root,
				path, BTRFS_FIRST_FREE_OBJECTID,
				tmp, strlen(tmp), 0);
		btrfs_release_path(path);
		if (IS_ERR(di)) {
			ret = PTR_ERR(di);
			goto out;
		}
		if (di) {
			/* not unique, try again */
			idx++;
			continue;
		}

		if (!sctx->parent_root) {
			/* unique */
			ret = 0;
			break;
		}

		di = btrfs_lookup_dir_item(NULL, sctx->parent_root,
				path, BTRFS_FIRST_FREE_OBJECTID,
				tmp, strlen(tmp), 0);
		btrfs_release_path(path);
		if (IS_ERR(di)) {
			ret = PTR_ERR(di);
			goto out;
		}
		if (di) {
			/* not unique, try again */
			idx++;
			continue;
		}
		/* unique */
		break;
	}

	ret = fs_path_add(dest, tmp, strlen(tmp));

out:
	btrfs_free_path(path);
	return ret;
}

enum inode_state {
	inode_state_no_change,
	inode_state_will_create,
	inode_state_did_create,
	inode_state_will_delete,
	inode_state_did_delete,
};

static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen)
{
	int ret;
	int left_ret;
	int right_ret;
	u64 left_gen;
	u64 right_gen;

	ret = get_inode_info(sctx->send_root, ino, NULL, &left_gen, NULL, NULL,
1428
			NULL, NULL);
1429 1430 1431 1432 1433 1434 1435 1436
	if (ret < 0 && ret != -ENOENT)
		goto out;
	left_ret = ret;

	if (!sctx->parent_root) {
		right_ret = -ENOENT;
	} else {
		ret = get_inode_info(sctx->parent_root, ino, NULL, &right_gen,
1437
				NULL, NULL, NULL, NULL);
1438 1439 1440 1441 1442 1443
		if (ret < 0 && ret != -ENOENT)
			goto out;
		right_ret = ret;
	}

	if (!left_ret && !right_ret) {
1444
		if (left_gen == gen && right_gen == gen) {
1445
			ret = inode_state_no_change;
1446
		} else if (left_gen == gen) {
1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539
			if (ino < sctx->send_progress)
				ret = inode_state_did_create;
			else
				ret = inode_state_will_create;
		} else if (right_gen == gen) {
			if (ino < sctx->send_progress)
				ret = inode_state_did_delete;
			else
				ret = inode_state_will_delete;
		} else  {
			ret = -ENOENT;
		}
	} else if (!left_ret) {
		if (left_gen == gen) {
			if (ino < sctx->send_progress)
				ret = inode_state_did_create;
			else
				ret = inode_state_will_create;
		} else {
			ret = -ENOENT;
		}
	} else if (!right_ret) {
		if (right_gen == gen) {
			if (ino < sctx->send_progress)
				ret = inode_state_did_delete;
			else
				ret = inode_state_will_delete;
		} else {
			ret = -ENOENT;
		}
	} else {
		ret = -ENOENT;
	}

out:
	return ret;
}

static int is_inode_existent(struct send_ctx *sctx, u64 ino, u64 gen)
{
	int ret;

	ret = get_cur_inode_state(sctx, ino, gen);
	if (ret < 0)
		goto out;

	if (ret == inode_state_no_change ||
	    ret == inode_state_did_create ||
	    ret == inode_state_will_delete)
		ret = 1;
	else
		ret = 0;

out:
	return ret;
}

/*
 * Helper function to lookup a dir item in a dir.
 */
static int lookup_dir_item_inode(struct btrfs_root *root,
				 u64 dir, const char *name, int name_len,
				 u64 *found_inode,
				 u8 *found_type)
{
	int ret = 0;
	struct btrfs_dir_item *di;
	struct btrfs_key key;
	struct btrfs_path *path;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	di = btrfs_lookup_dir_item(NULL, root, path,
			dir, name, name_len, 0);
	if (!di) {
		ret = -ENOENT;
		goto out;
	}
	if (IS_ERR(di)) {
		ret = PTR_ERR(di);
		goto out;
	}
	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
	*found_inode = key.objectid;
	*found_type = btrfs_dir_type(path->nodes[0], di);

out:
	btrfs_free_path(path);
	return ret;
}

1540 1541 1542 1543
/*
 * Looks up the first btrfs_inode_ref of a given ino. It returns the parent dir,
 * generation of the parent dir and the name of the dir entry.
 */
1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584
static int get_first_ref(struct send_ctx *sctx,
			 struct btrfs_root *root, u64 ino,
			 u64 *dir, u64 *dir_gen, struct fs_path *name)
{
	int ret;
	struct btrfs_key key;
	struct btrfs_key found_key;
	struct btrfs_path *path;
	struct btrfs_inode_ref *iref;
	int len;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	key.objectid = ino;
	key.type = BTRFS_INODE_REF_KEY;
	key.offset = 0;

	ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
	if (ret < 0)
		goto out;
	if (!ret)
		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
				path->slots[0]);
	if (ret || found_key.objectid != key.objectid ||
	    found_key.type != key.type) {
		ret = -ENOENT;
		goto out;
	}

	iref = btrfs_item_ptr(path->nodes[0], path->slots[0],
			struct btrfs_inode_ref);
	len = btrfs_inode_ref_name_len(path->nodes[0], iref);
	ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
			(unsigned long)(iref + 1), len);
	if (ret < 0)
		goto out;
	btrfs_release_path(path);

	ret = get_inode_info(root, found_key.offset, NULL, dir_gen, NULL, NULL,
1585
			NULL, NULL);
1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613
	if (ret < 0)
		goto out;

	*dir = found_key.offset;

out:
	btrfs_free_path(path);
	return ret;
}

static int is_first_ref(struct send_ctx *sctx,
			struct btrfs_root *root,
			u64 ino, u64 dir,
			const char *name, int name_len)
{
	int ret;
	struct fs_path *tmp_name;
	u64 tmp_dir;
	u64 tmp_dir_gen;

	tmp_name = fs_path_alloc(sctx);
	if (!tmp_name)
		return -ENOMEM;

	ret = get_first_ref(sctx, root, ino, &tmp_dir, &tmp_dir_gen, tmp_name);
	if (ret < 0)
		goto out;

1614
	if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) {
1615 1616 1617 1618
		ret = 0;
		goto out;
	}

1619
	ret = !memcmp(tmp_name->start, name, name_len);
1620 1621 1622 1623 1624 1625

out:
	fs_path_free(sctx, tmp_name);
	return ret;
}

1626 1627 1628 1629 1630 1631 1632 1633 1634 1635
/*
 * Used by process_recorded_refs to determine if a new ref would overwrite an
 * already existing ref. In case it detects an overwrite, it returns the
 * inode/gen in who_ino/who_gen.
 * When an overwrite is detected, process_recorded_refs does proper orphanizing
 * to make sure later references to the overwritten inode are possible.
 * Orphanizing is however only required for the first ref of an inode.
 * process_recorded_refs does an additional is_first_ref check to see if
 * orphanizing is really required.
 */
1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659
static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
			      const char *name, int name_len,
			      u64 *who_ino, u64 *who_gen)
{
	int ret = 0;
	u64 other_inode = 0;
	u8 other_type = 0;

	if (!sctx->parent_root)
		goto out;

	ret = is_inode_existent(sctx, dir, dir_gen);
	if (ret <= 0)
		goto out;

	ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
			&other_inode, &other_type);
	if (ret < 0 && ret != -ENOENT)
		goto out;
	if (ret) {
		ret = 0;
		goto out;
	}

1660 1661 1662 1663 1664
	/*
	 * Check if the overwritten ref was already processed. If yes, the ref
	 * was already unlinked/moved, so we can safely assume that we will not
	 * overwrite anything at this point in time.
	 */
1665 1666
	if (other_inode > sctx->send_progress) {
		ret = get_inode_info(sctx->parent_root, other_inode, NULL,
1667
				who_gen, NULL, NULL, NULL, NULL);
1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680
		if (ret < 0)
			goto out;

		ret = 1;
		*who_ino = other_inode;
	} else {
		ret = 0;
	}

out:
	return ret;
}

1681 1682 1683 1684 1685 1686 1687
/*
 * Checks if the ref was overwritten by an already processed inode. This is
 * used by __get_cur_name_and_parent to find out if the ref was orphanized and
 * thus the orphan name needs be used.
 * process_recorded_refs also uses it to avoid unlinking of refs that were
 * overwritten.
 */
1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716
static int did_overwrite_ref(struct send_ctx *sctx,
			    u64 dir, u64 dir_gen,
			    u64 ino, u64 ino_gen,
			    const char *name, int name_len)
{
	int ret = 0;
	u64 gen;
	u64 ow_inode;
	u8 other_type;

	if (!sctx->parent_root)
		goto out;

	ret = is_inode_existent(sctx, dir, dir_gen);
	if (ret <= 0)
		goto out;

	/* check if the ref was overwritten by another ref */
	ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
			&ow_inode, &other_type);
	if (ret < 0 && ret != -ENOENT)
		goto out;
	if (ret) {
		/* was never and will never be overwritten */
		ret = 0;
		goto out;
	}

	ret = get_inode_info(sctx->send_root, ow_inode, NULL, &gen, NULL, NULL,
1717
			NULL, NULL);
1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735
	if (ret < 0)
		goto out;

	if (ow_inode == ino && gen == ino_gen) {
		ret = 0;
		goto out;
	}

	/* we know that it is or will be overwritten. check this now */
	if (ow_inode < sctx->send_progress)
		ret = 1;
	else
		ret = 0;

out:
	return ret;
}

1736 1737 1738 1739 1740
/*
 * Same as did_overwrite_ref, but also checks if it is the first ref of an inode
 * that got overwritten. This is used by process_recorded_refs to determine
 * if it has to use the path as returned by get_cur_path or the orphan name.
 */
1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766
static int did_overwrite_first_ref(struct send_ctx *sctx, u64 ino, u64 gen)
{
	int ret = 0;
	struct fs_path *name = NULL;
	u64 dir;
	u64 dir_gen;

	if (!sctx->parent_root)
		goto out;

	name = fs_path_alloc(sctx);
	if (!name)
		return -ENOMEM;

	ret = get_first_ref(sctx, sctx->parent_root, ino, &dir, &dir_gen, name);
	if (ret < 0)
		goto out;

	ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen,
			name->start, fs_path_len(name));

out:
	fs_path_free(sctx, name);
	return ret;
}

1767 1768 1769 1770
/*
 * Insert a name cache entry. On 32bit kernels the radix tree index is 32bit,
 * so we need to do some special handling in case we have clashes. This function
 * takes care of this with the help of name_cache_entry::radix_list.
1771
 * In case of error, nce is kfreed.
1772
 */
1773 1774 1775 1776
static int name_cache_insert(struct send_ctx *sctx,
			     struct name_cache_entry *nce)
{
	int ret = 0;
1777 1778 1779 1780 1781 1782 1783
	struct list_head *nce_head;

	nce_head = radix_tree_lookup(&sctx->name_cache,
			(unsigned long)nce->ino);
	if (!nce_head) {
		nce_head = kmalloc(sizeof(*nce_head), GFP_NOFS);
		if (!nce_head)
1784
			return -ENOMEM;
1785
		INIT_LIST_HEAD(nce_head);
1786

1787
		ret = radix_tree_insert(&sctx->name_cache, nce->ino, nce_head);
1788 1789 1790
		if (ret < 0) {
			kfree(nce_head);
			kfree(nce);
1791
			return ret;
1792
		}
1793
	}
1794
	list_add_tail(&nce->radix_list, nce_head);
1795 1796 1797 1798 1799 1800 1801 1802 1803
	list_add_tail(&nce->list, &sctx->name_cache_list);
	sctx->name_cache_size++;

	return ret;
}

static void name_cache_delete(struct send_ctx *sctx,
			      struct name_cache_entry *nce)
{
1804
	struct list_head *nce_head;
1805

1806 1807 1808
	nce_head = radix_tree_lookup(&sctx->name_cache,
			(unsigned long)nce->ino);
	BUG_ON(!nce_head);
1809

1810
	list_del(&nce->radix_list);
1811 1812
	list_del(&nce->list);
	sctx->name_cache_size--;
1813 1814 1815 1816 1817

	if (list_empty(nce_head)) {
		radix_tree_delete(&sctx->name_cache, (unsigned long)nce->ino);
		kfree(nce_head);
	}
1818 1819 1820 1821 1822
}

static struct name_cache_entry *name_cache_search(struct send_ctx *sctx,
						    u64 ino, u64 gen)
{
1823 1824
	struct list_head *nce_head;
	struct name_cache_entry *cur;
1825

1826 1827
	nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)ino);
	if (!nce_head)
1828 1829
		return NULL;

1830 1831 1832 1833
	list_for_each_entry(cur, nce_head, radix_list) {
		if (cur->ino == ino && cur->gen == gen)
			return cur;
	}
1834 1835 1836
	return NULL;
}

1837 1838 1839 1840
/*
 * Removes the entry from the list and adds it back to the end. This marks the
 * entry as recently used so that name_cache_clean_unused does not remove it.
 */
1841 1842 1843 1844 1845 1846
static void name_cache_used(struct send_ctx *sctx, struct name_cache_entry *nce)
{
	list_del(&nce->list);
	list_add_tail(&nce->list, &sctx->name_cache_list);
}

1847 1848 1849
/*
 * Remove some entries from the beginning of name_cache_list.
 */
1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868
static void name_cache_clean_unused(struct send_ctx *sctx)
{
	struct name_cache_entry *nce;

	if (sctx->name_cache_size < SEND_CTX_NAME_CACHE_CLEAN_SIZE)
		return;

	while (sctx->name_cache_size > SEND_CTX_MAX_NAME_CACHE_SIZE) {
		nce = list_entry(sctx->name_cache_list.next,
				struct name_cache_entry, list);
		name_cache_delete(sctx, nce);
		kfree(nce);
	}
}

static void name_cache_free(struct send_ctx *sctx)
{
	struct name_cache_entry *nce;

1869 1870 1871
	while (!list_empty(&sctx->name_cache_list)) {
		nce = list_entry(sctx->name_cache_list.next,
				struct name_cache_entry, list);
1872
		name_cache_delete(sctx, nce);
1873
		kfree(nce);
1874 1875 1876
	}
}

1877 1878 1879 1880 1881 1882 1883 1884
/*
 * Used by get_cur_path for each ref up to the root.
 * Returns 0 if it succeeded.
 * Returns 1 if the inode is not existent or got overwritten. In that case, the
 * name is an orphan name. This instructs get_cur_path to stop iterating. If 1
 * is returned, parent_ino/parent_gen are not guaranteed to be valid.
 * Returns <0 in case of error.
 */
1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895
static int __get_cur_name_and_parent(struct send_ctx *sctx,
				     u64 ino, u64 gen,
				     u64 *parent_ino,
				     u64 *parent_gen,
				     struct fs_path *dest)
{
	int ret;
	int nce_ret;
	struct btrfs_path *path = NULL;
	struct name_cache_entry *nce = NULL;

1896 1897 1898 1899 1900
	/*
	 * First check if we already did a call to this function with the same
	 * ino/gen. If yes, check if the cache entry is still up-to-date. If yes
	 * return the cached result.
	 */
1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922
	nce = name_cache_search(sctx, ino, gen);
	if (nce) {
		if (ino < sctx->send_progress && nce->need_later_update) {
			name_cache_delete(sctx, nce);
			kfree(nce);
			nce = NULL;
		} else {
			name_cache_used(sctx, nce);
			*parent_ino = nce->parent_ino;
			*parent_gen = nce->parent_gen;
			ret = fs_path_add(dest, nce->name, nce->name_len);
			if (ret < 0)
				goto out;
			ret = nce->ret;
			goto out;
		}
	}

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

1923 1924 1925 1926 1927
	/*
	 * If the inode is not existent yet, add the orphan name and return 1.
	 * This should only happen for the parent dir that we determine in
	 * __record_new_ref
	 */
1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939
	ret = is_inode_existent(sctx, ino, gen);
	if (ret < 0)
		goto out;

	if (!ret) {
		ret = gen_unique_name(sctx, ino, gen, dest);
		if (ret < 0)
			goto out;
		ret = 1;
		goto out_cache;
	}

1940 1941 1942 1943
	/*
	 * Depending on whether the inode was already processed or not, use
	 * send_root or parent_root for ref lookup.
	 */
1944 1945 1946 1947 1948 1949 1950 1951 1952
	if (ino < sctx->send_progress)
		ret = get_first_ref(sctx, sctx->send_root, ino,
				parent_ino, parent_gen, dest);
	else
		ret = get_first_ref(sctx, sctx->parent_root, ino,
				parent_ino, parent_gen, dest);
	if (ret < 0)
		goto out;

1953 1954 1955 1956
	/*
	 * Check if the ref was overwritten by an inode's ref that was processed
	 * earlier. If yes, treat as orphan and return 1.
	 */
1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
	ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen,
			dest->start, dest->end - dest->start);
	if (ret < 0)
		goto out;
	if (ret) {
		fs_path_reset(dest);
		ret = gen_unique_name(sctx, ino, gen, dest);
		if (ret < 0)
			goto out;
		ret = 1;
	}

out_cache:
1970 1971 1972
	/*
	 * Store the result of the lookup in the name cache.
	 */
1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077
	nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_NOFS);
	if (!nce) {
		ret = -ENOMEM;
		goto out;
	}

	nce->ino = ino;
	nce->gen = gen;
	nce->parent_ino = *parent_ino;
	nce->parent_gen = *parent_gen;
	nce->name_len = fs_path_len(dest);
	nce->ret = ret;
	strcpy(nce->name, dest->start);

	if (ino < sctx->send_progress)
		nce->need_later_update = 0;
	else
		nce->need_later_update = 1;

	nce_ret = name_cache_insert(sctx, nce);
	if (nce_ret < 0)
		ret = nce_ret;
	name_cache_clean_unused(sctx);

out:
	btrfs_free_path(path);
	return ret;
}

/*
 * Magic happens here. This function returns the first ref to an inode as it
 * would look like while receiving the stream at this point in time.
 * We walk the path up to the root. For every inode in between, we check if it
 * was already processed/sent. If yes, we continue with the parent as found
 * in send_root. If not, we continue with the parent as found in parent_root.
 * If we encounter an inode that was deleted at this point in time, we use the
 * inodes "orphan" name instead of the real name and stop. Same with new inodes
 * that were not created yet and overwritten inodes/refs.
 *
 * When do we have have orphan inodes:
 * 1. When an inode is freshly created and thus no valid refs are available yet
 * 2. When a directory lost all it's refs (deleted) but still has dir items
 *    inside which were not processed yet (pending for move/delete). If anyone
 *    tried to get the path to the dir items, it would get a path inside that
 *    orphan directory.
 * 3. When an inode is moved around or gets new links, it may overwrite the ref
 *    of an unprocessed inode. If in that case the first ref would be
 *    overwritten, the overwritten inode gets "orphanized". Later when we
 *    process this overwritten inode, it is restored at a new place by moving
 *    the orphan inode.
 *
 * sctx->send_progress tells this function at which point in time receiving
 * would be.
 */
static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen,
			struct fs_path *dest)
{
	int ret = 0;
	struct fs_path *name = NULL;
	u64 parent_inode = 0;
	u64 parent_gen = 0;
	int stop = 0;

	name = fs_path_alloc(sctx);
	if (!name) {
		ret = -ENOMEM;
		goto out;
	}

	dest->reversed = 1;
	fs_path_reset(dest);

	while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) {
		fs_path_reset(name);

		ret = __get_cur_name_and_parent(sctx, ino, gen,
				&parent_inode, &parent_gen, name);
		if (ret < 0)
			goto out;
		if (ret)
			stop = 1;

		ret = fs_path_add_path(dest, name);
		if (ret < 0)
			goto out;

		ino = parent_inode;
		gen = parent_gen;
	}

out:
	fs_path_free(sctx, name);
	if (!ret)
		fs_path_unreverse(dest);
	return ret;
}

/*
 * Called for regular files when sending extents data. Opens a struct file
 * to read from the file.
 */
static int open_cur_inode_file(struct send_ctx *sctx)
{
	int ret = 0;
	struct btrfs_key key;
2078
	struct path path;
2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104
	struct inode *inode;
	struct dentry *dentry;
	struct file *filp;
	int new = 0;

	if (sctx->cur_inode_filp)
		goto out;

	key.objectid = sctx->cur_ino;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;

	inode = btrfs_iget(sctx->send_root->fs_info->sb, &key, sctx->send_root,
			&new);
	if (IS_ERR(inode)) {
		ret = PTR_ERR(inode);
		goto out;
	}

	dentry = d_obtain_alias(inode);
	inode = NULL;
	if (IS_ERR(dentry)) {
		ret = PTR_ERR(dentry);
		goto out;
	}

2105 2106 2107 2108
	path.mnt = sctx->mnt;
	path.dentry = dentry;
	filp = dentry_open(&path, O_RDONLY | O_LARGEFILE, current_cred());
	dput(dentry);
2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356
	dentry = NULL;
	if (IS_ERR(filp)) {
		ret = PTR_ERR(filp);
		goto out;
	}
	sctx->cur_inode_filp = filp;

out:
	/*
	 * no xxxput required here as every vfs op
	 * does it by itself on failure
	 */
	return ret;
}

/*
 * Closes the struct file that was created in open_cur_inode_file
 */
static int close_cur_inode_file(struct send_ctx *sctx)
{
	int ret = 0;

	if (!sctx->cur_inode_filp)
		goto out;

	ret = filp_close(sctx->cur_inode_filp, NULL);
	sctx->cur_inode_filp = NULL;

out:
	return ret;
}

/*
 * Sends a BTRFS_SEND_C_SUBVOL command/item to userspace
 */
static int send_subvol_begin(struct send_ctx *sctx)
{
	int ret;
	struct btrfs_root *send_root = sctx->send_root;
	struct btrfs_root *parent_root = sctx->parent_root;
	struct btrfs_path *path;
	struct btrfs_key key;
	struct btrfs_root_ref *ref;
	struct extent_buffer *leaf;
	char *name = NULL;
	int namelen;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_NOFS);
	if (!name) {
		btrfs_free_path(path);
		return -ENOMEM;
	}

	key.objectid = send_root->objectid;
	key.type = BTRFS_ROOT_BACKREF_KEY;
	key.offset = 0;

	ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root,
				&key, path, 1, 0);
	if (ret < 0)
		goto out;
	if (ret) {
		ret = -ENOENT;
		goto out;
	}

	leaf = path->nodes[0];
	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
	if (key.type != BTRFS_ROOT_BACKREF_KEY ||
	    key.objectid != send_root->objectid) {
		ret = -ENOENT;
		goto out;
	}
	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
	namelen = btrfs_root_ref_name_len(leaf, ref);
	read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen);
	btrfs_release_path(path);

	if (parent_root) {
		ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT);
		if (ret < 0)
			goto out;
	} else {
		ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL);
		if (ret < 0)
			goto out;
	}

	TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen);
	TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
			sctx->send_root->root_item.uuid);
	TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID,
			sctx->send_root->root_item.ctransid);
	if (parent_root) {
		TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
				sctx->parent_root->root_item.uuid);
		TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
				sctx->parent_root->root_item.ctransid);
	}

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	btrfs_free_path(path);
	kfree(name);
	return ret;
}

static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size)
{
	int ret = 0;
	struct fs_path *p;

verbose_printk("btrfs: send_truncate %llu size=%llu\n", ino, size);

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE);
	if (ret < 0)
		goto out;

	ret = get_cur_path(sctx, ino, gen, p);
	if (ret < 0)
		goto out;
	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
	TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	fs_path_free(sctx, p);
	return ret;
}

static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode)
{
	int ret = 0;
	struct fs_path *p;

verbose_printk("btrfs: send_chmod %llu mode=%llu\n", ino, mode);

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD);
	if (ret < 0)
		goto out;

	ret = get_cur_path(sctx, ino, gen, p);
	if (ret < 0)
		goto out;
	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
	TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	fs_path_free(sctx, p);
	return ret;
}

static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid)
{
	int ret = 0;
	struct fs_path *p;

verbose_printk("btrfs: send_chown %llu uid=%llu, gid=%llu\n", ino, uid, gid);

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN);
	if (ret < 0)
		goto out;

	ret = get_cur_path(sctx, ino, gen, p);
	if (ret < 0)
		goto out;
	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
	TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid);
	TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	fs_path_free(sctx, p);
	return ret;
}

static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen)
{
	int ret = 0;
	struct fs_path *p = NULL;
	struct btrfs_inode_item *ii;
	struct btrfs_path *path = NULL;
	struct extent_buffer *eb;
	struct btrfs_key key;
	int slot;

verbose_printk("btrfs: send_utimes %llu\n", ino);

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	path = alloc_path_for_send();
	if (!path) {
		ret = -ENOMEM;
		goto out;
	}

	key.objectid = ino;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;
	ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
	if (ret < 0)
		goto out;

	eb = path->nodes[0];
	slot = path->slots[0];
	ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);

	ret = begin_cmd(sctx, BTRFS_SEND_C_UTIMES);
	if (ret < 0)
		goto out;

	ret = get_cur_path(sctx, ino, gen, p);
	if (ret < 0)
		goto out;
	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
	TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, eb,
			btrfs_inode_atime(ii));
	TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb,
			btrfs_inode_mtime(ii));
	TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb,
			btrfs_inode_ctime(ii));
2357
	/* TODO Add otime support when the otime patches get into upstream */
2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	fs_path_free(sctx, p);
	btrfs_free_path(path);
	return ret;
}

/*
 * Sends a BTRFS_SEND_C_MKXXX or SYMLINK command to user space. We don't have
 * a valid path yet because we did not process the refs yet. So, the inode
 * is created as orphan.
 */
2373
static int send_create_inode(struct send_ctx *sctx, u64 ino)
2374 2375 2376 2377
{
	int ret = 0;
	struct fs_path *p;
	int cmd;
2378
	u64 gen;
2379
	u64 mode;
2380
	u64 rdev;
2381

2382
verbose_printk("btrfs: send_create_inode %llu\n", ino);
2383 2384 2385 2386 2387

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

2388 2389 2390 2391
	ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode, NULL,
			NULL, &rdev);
	if (ret < 0)
		goto out;
2392

2393
	if (S_ISREG(mode)) {
2394
		cmd = BTRFS_SEND_C_MKFILE;
2395
	} else if (S_ISDIR(mode)) {
2396
		cmd = BTRFS_SEND_C_MKDIR;
2397
	} else if (S_ISLNK(mode)) {
2398
		cmd = BTRFS_SEND_C_SYMLINK;
2399
	} else if (S_ISCHR(mode) || S_ISBLK(mode)) {
2400
		cmd = BTRFS_SEND_C_MKNOD;
2401
	} else if (S_ISFIFO(mode)) {
2402
		cmd = BTRFS_SEND_C_MKFIFO;
2403
	} else if (S_ISSOCK(mode)) {
2404
		cmd = BTRFS_SEND_C_MKSOCK;
2405
	} else {
2406 2407 2408 2409 2410 2411 2412 2413 2414 2415
		printk(KERN_WARNING "btrfs: unexpected inode type %o",
				(int)(mode & S_IFMT));
		ret = -ENOTSUPP;
		goto out;
	}

	ret = begin_cmd(sctx, cmd);
	if (ret < 0)
		goto out;

2416
	ret = gen_unique_name(sctx, ino, gen, p);
2417 2418 2419 2420
	if (ret < 0)
		goto out;

	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
2421
	TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino);
2422 2423 2424

	if (S_ISLNK(mode)) {
		fs_path_reset(p);
2425
		ret = read_symlink(sctx, sctx->send_root, ino, p);
2426 2427 2428 2429 2430
		if (ret < 0)
			goto out;
		TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p);
	} else if (S_ISCHR(mode) || S_ISBLK(mode) ||
		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
2431
		TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, rdev);
2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444
	}

	ret = send_cmd(sctx);
	if (ret < 0)
		goto out;


tlv_put_failure:
out:
	fs_path_free(sctx, p);
	return ret;
}

2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530
/*
 * We need some special handling for inodes that get processed before the parent
 * directory got created. See process_recorded_refs for details.
 * This function does the check if we already created the dir out of order.
 */
static int did_create_dir(struct send_ctx *sctx, u64 dir)
{
	int ret = 0;
	struct btrfs_path *path = NULL;
	struct btrfs_key key;
	struct btrfs_key found_key;
	struct btrfs_key di_key;
	struct extent_buffer *eb;
	struct btrfs_dir_item *di;
	int slot;

	path = alloc_path_for_send();
	if (!path) {
		ret = -ENOMEM;
		goto out;
	}

	key.objectid = dir;
	key.type = BTRFS_DIR_INDEX_KEY;
	key.offset = 0;
	while (1) {
		ret = btrfs_search_slot_for_read(sctx->send_root, &key, path,
				1, 0);
		if (ret < 0)
			goto out;
		if (!ret) {
			eb = path->nodes[0];
			slot = path->slots[0];
			btrfs_item_key_to_cpu(eb, &found_key, slot);
		}
		if (ret || found_key.objectid != key.objectid ||
		    found_key.type != key.type) {
			ret = 0;
			goto out;
		}

		di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
		btrfs_dir_item_key_to_cpu(eb, di, &di_key);

		if (di_key.objectid < sctx->send_progress) {
			ret = 1;
			goto out;
		}

		key.offset = found_key.offset + 1;
		btrfs_release_path(path);
	}

out:
	btrfs_free_path(path);
	return ret;
}

/*
 * Only creates the inode if it is:
 * 1. Not a directory
 * 2. Or a directory which was not created already due to out of order
 *    directories. See did_create_dir and process_recorded_refs for details.
 */
static int send_create_inode_if_needed(struct send_ctx *sctx)
{
	int ret;

	if (S_ISDIR(sctx->cur_inode_mode)) {
		ret = did_create_dir(sctx, sctx->cur_ino);
		if (ret < 0)
			goto out;
		if (ret) {
			ret = 0;
			goto out;
		}
	}

	ret = send_create_inode(sctx, sctx->cur_ino);
	if (ret < 0)
		goto out;

out:
	return ret;
}

2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583
struct recorded_ref {
	struct list_head list;
	char *dir_path;
	char *name;
	struct fs_path *full_path;
	u64 dir;
	u64 dir_gen;
	int dir_path_len;
	int name_len;
};

/*
 * We need to process new refs before deleted refs, but compare_tree gives us
 * everything mixed. So we first record all refs and later process them.
 * This function is a helper to record one ref.
 */
static int record_ref(struct list_head *head, u64 dir,
		      u64 dir_gen, struct fs_path *path)
{
	struct recorded_ref *ref;
	char *tmp;

	ref = kmalloc(sizeof(*ref), GFP_NOFS);
	if (!ref)
		return -ENOMEM;

	ref->dir = dir;
	ref->dir_gen = dir_gen;
	ref->full_path = path;

	tmp = strrchr(ref->full_path->start, '/');
	if (!tmp) {
		ref->name_len = ref->full_path->end - ref->full_path->start;
		ref->name = ref->full_path->start;
		ref->dir_path_len = 0;
		ref->dir_path = ref->full_path->start;
	} else {
		tmp++;
		ref->name_len = ref->full_path->end - tmp;
		ref->name = tmp;
		ref->dir_path = ref->full_path->start;
		ref->dir_path_len = ref->full_path->end -
				ref->full_path->start - 1 - ref->name_len;
	}

	list_add_tail(&ref->list, head);
	return 0;
}

static void __free_recorded_refs(struct send_ctx *sctx, struct list_head *head)
{
	struct recorded_ref *cur;

2584 2585
	while (!list_empty(head)) {
		cur = list_entry(head->next, struct recorded_ref, list);
2586
		fs_path_free(sctx, cur->full_path);
2587
		list_del(&cur->list);
2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598
		kfree(cur);
	}
}

static void free_recorded_refs(struct send_ctx *sctx)
{
	__free_recorded_refs(sctx, &sctx->new_refs);
	__free_recorded_refs(sctx, &sctx->deleted_refs);
}

/*
2599
 * Renames/moves a file/dir to its orphan name. Used when the first
2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638
 * ref of an unprocessed inode gets overwritten and for all non empty
 * directories.
 */
static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen,
			  struct fs_path *path)
{
	int ret;
	struct fs_path *orphan;

	orphan = fs_path_alloc(sctx);
	if (!orphan)
		return -ENOMEM;

	ret = gen_unique_name(sctx, ino, gen, orphan);
	if (ret < 0)
		goto out;

	ret = send_rename(sctx, path, orphan);

out:
	fs_path_free(sctx, orphan);
	return ret;
}

/*
 * Returns 1 if a directory can be removed at this point in time.
 * We check this by iterating all dir items and checking if the inode behind
 * the dir item was already processed.
 */
static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 send_progress)
{
	int ret = 0;
	struct btrfs_root *root = sctx->parent_root;
	struct btrfs_path *path;
	struct btrfs_key key;
	struct btrfs_key found_key;
	struct btrfs_key loc;
	struct btrfs_dir_item *di;

2639 2640 2641 2642 2643 2644
	/*
	 * Don't try to rmdir the top/root subvolume dir.
	 */
	if (dir == BTRFS_FIRST_FREE_OBJECTID)
		return 0;

2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692
	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	key.objectid = dir;
	key.type = BTRFS_DIR_INDEX_KEY;
	key.offset = 0;

	while (1) {
		ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
		if (ret < 0)
			goto out;
		if (!ret) {
			btrfs_item_key_to_cpu(path->nodes[0], &found_key,
					path->slots[0]);
		}
		if (ret || found_key.objectid != key.objectid ||
		    found_key.type != key.type) {
			break;
		}

		di = btrfs_item_ptr(path->nodes[0], path->slots[0],
				struct btrfs_dir_item);
		btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc);

		if (loc.objectid > send_progress) {
			ret = 0;
			goto out;
		}

		btrfs_release_path(path);
		key.offset = found_key.offset + 1;
	}

	ret = 1;

out:
	btrfs_free_path(path);
	return ret;
}

/*
 * This does all the move/link/unlink/rmdir magic.
 */
static int process_recorded_refs(struct send_ctx *sctx)
{
	int ret = 0;
	struct recorded_ref *cur;
2693
	struct recorded_ref *cur2;
2694 2695 2696 2697
	struct ulist *check_dirs = NULL;
	struct ulist_iterator uit;
	struct ulist_node *un;
	struct fs_path *valid_path = NULL;
2698
	u64 ow_inode = 0;
2699 2700 2701 2702 2703 2704
	u64 ow_gen;
	int did_overwrite = 0;
	int is_orphan = 0;

verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);

2705 2706 2707 2708 2709 2710
	/*
	 * This should never happen as the root dir always has the same ref
	 * which is always '..'
	 */
	BUG_ON(sctx->cur_ino <= BTRFS_FIRST_FREE_OBJECTID);

2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755
	valid_path = fs_path_alloc(sctx);
	if (!valid_path) {
		ret = -ENOMEM;
		goto out;
	}

	check_dirs = ulist_alloc(GFP_NOFS);
	if (!check_dirs) {
		ret = -ENOMEM;
		goto out;
	}

	/*
	 * First, check if the first ref of the current inode was overwritten
	 * before. If yes, we know that the current inode was already orphanized
	 * and thus use the orphan name. If not, we can use get_cur_path to
	 * get the path of the first ref as it would like while receiving at
	 * this point in time.
	 * New inodes are always orphan at the beginning, so force to use the
	 * orphan name in this case.
	 * The first ref is stored in valid_path and will be updated if it
	 * gets moved around.
	 */
	if (!sctx->cur_inode_new) {
		ret = did_overwrite_first_ref(sctx, sctx->cur_ino,
				sctx->cur_inode_gen);
		if (ret < 0)
			goto out;
		if (ret)
			did_overwrite = 1;
	}
	if (sctx->cur_inode_new || did_overwrite) {
		ret = gen_unique_name(sctx, sctx->cur_ino,
				sctx->cur_inode_gen, valid_path);
		if (ret < 0)
			goto out;
		is_orphan = 1;
	} else {
		ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen,
				valid_path);
		if (ret < 0)
			goto out;
	}

	list_for_each_entry(cur, &sctx->new_refs, list) {
2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795
		/*
		 * We may have refs where the parent directory does not exist
		 * yet. This happens if the parent directories inum is higher
		 * the the current inum. To handle this case, we create the
		 * parent directory out of order. But we need to check if this
		 * did already happen before due to other refs in the same dir.
		 */
		ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
		if (ret < 0)
			goto out;
		if (ret == inode_state_will_create) {
			ret = 0;
			/*
			 * First check if any of the current inodes refs did
			 * already create the dir.
			 */
			list_for_each_entry(cur2, &sctx->new_refs, list) {
				if (cur == cur2)
					break;
				if (cur2->dir == cur->dir) {
					ret = 1;
					break;
				}
			}

			/*
			 * If that did not happen, check if a previous inode
			 * did already create the dir.
			 */
			if (!ret)
				ret = did_create_dir(sctx, cur->dir);
			if (ret < 0)
				goto out;
			if (!ret) {
				ret = send_create_inode(sctx, cur->dir);
				if (ret < 0)
					goto out;
			}
		}

2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829
		/*
		 * Check if this new ref would overwrite the first ref of
		 * another unprocessed inode. If yes, orphanize the
		 * overwritten inode. If we find an overwritten ref that is
		 * not the first ref, simply unlink it.
		 */
		ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen,
				cur->name, cur->name_len,
				&ow_inode, &ow_gen);
		if (ret < 0)
			goto out;
		if (ret) {
			ret = is_first_ref(sctx, sctx->parent_root,
					ow_inode, cur->dir, cur->name,
					cur->name_len);
			if (ret < 0)
				goto out;
			if (ret) {
				ret = orphanize_inode(sctx, ow_inode, ow_gen,
						cur->full_path);
				if (ret < 0)
					goto out;
			} else {
				ret = send_unlink(sctx, cur->full_path);
				if (ret < 0)
					goto out;
			}
		}

		/*
		 * link/move the ref to the new place. If we have an orphan
		 * inode, move it and update valid_path. If not, link or move
		 * it depending on the inode mode.
		 */
2830
		if (is_orphan) {
2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892
			ret = send_rename(sctx, valid_path, cur->full_path);
			if (ret < 0)
				goto out;
			is_orphan = 0;
			ret = fs_path_copy(valid_path, cur->full_path);
			if (ret < 0)
				goto out;
		} else {
			if (S_ISDIR(sctx->cur_inode_mode)) {
				/*
				 * Dirs can't be linked, so move it. For moved
				 * dirs, we always have one new and one deleted
				 * ref. The deleted ref is ignored later.
				 */
				ret = send_rename(sctx, valid_path,
						cur->full_path);
				if (ret < 0)
					goto out;
				ret = fs_path_copy(valid_path, cur->full_path);
				if (ret < 0)
					goto out;
			} else {
				ret = send_link(sctx, cur->full_path,
						valid_path);
				if (ret < 0)
					goto out;
			}
		}
		ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
				GFP_NOFS);
		if (ret < 0)
			goto out;
	}

	if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) {
		/*
		 * Check if we can already rmdir the directory. If not,
		 * orphanize it. For every dir item inside that gets deleted
		 * later, we do this check again and rmdir it then if possible.
		 * See the use of check_dirs for more details.
		 */
		ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_ino);
		if (ret < 0)
			goto out;
		if (ret) {
			ret = send_rmdir(sctx, valid_path);
			if (ret < 0)
				goto out;
		} else if (!is_orphan) {
			ret = orphanize_inode(sctx, sctx->cur_ino,
					sctx->cur_inode_gen, valid_path);
			if (ret < 0)
				goto out;
			is_orphan = 1;
		}

		list_for_each_entry(cur, &sctx->deleted_refs, list) {
			ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
					GFP_NOFS);
			if (ret < 0)
				goto out;
		}
2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903
	} else if (S_ISDIR(sctx->cur_inode_mode) &&
		   !list_empty(&sctx->deleted_refs)) {
		/*
		 * We have a moved dir. Add the old parent to check_dirs
		 */
		cur = list_entry(sctx->deleted_refs.next, struct recorded_ref,
				list);
		ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
				GFP_NOFS);
		if (ret < 0)
			goto out;
2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916
	} else if (!S_ISDIR(sctx->cur_inode_mode)) {
		/*
		 * We have a non dir inode. Go through all deleted refs and
		 * unlink them if they were not already overwritten by other
		 * inodes.
		 */
		list_for_each_entry(cur, &sctx->deleted_refs, list) {
			ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen,
					sctx->cur_ino, sctx->cur_inode_gen,
					cur->name, cur->name_len);
			if (ret < 0)
				goto out;
			if (!ret) {
2917 2918 2919
				ret = send_unlink(sctx, cur->full_path);
				if (ret < 0)
					goto out;
2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930
			}
			ret = ulist_add(check_dirs, cur->dir, cur->dir_gen,
					GFP_NOFS);
			if (ret < 0)
				goto out;
		}

		/*
		 * If the inode is still orphan, unlink the orphan. This may
		 * happen when a previous inode did overwrite the first ref
		 * of this inode and no new refs were added for the current
2931 2932 2933
		 * inode. Unlinking does not mean that the inode is deleted in
		 * all cases. There may still be links to this inode in other
		 * places.
2934
		 */
2935
		if (is_orphan) {
2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949
			ret = send_unlink(sctx, valid_path);
			if (ret < 0)
				goto out;
		}
	}

	/*
	 * We did collect all parent dirs where cur_inode was once located. We
	 * now go through all these dirs and check if they are pending for
	 * deletion and if it's finally possible to perform the rmdir now.
	 * We also update the inode stats of the parent dirs here.
	 */
	ULIST_ITER_INIT(&uit);
	while ((un = ulist_next(check_dirs, &uit))) {
2950 2951 2952 2953 2954
		/*
		 * In case we had refs into dirs that were not processed yet,
		 * we don't need to do the utime and rmdir logic for these dirs.
		 * The dir will be processed later.
		 */
2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006
		if (un->val > sctx->cur_ino)
			continue;

		ret = get_cur_inode_state(sctx, un->val, un->aux);
		if (ret < 0)
			goto out;

		if (ret == inode_state_did_create ||
		    ret == inode_state_no_change) {
			/* TODO delayed utimes */
			ret = send_utimes(sctx, un->val, un->aux);
			if (ret < 0)
				goto out;
		} else if (ret == inode_state_did_delete) {
			ret = can_rmdir(sctx, un->val, sctx->cur_ino);
			if (ret < 0)
				goto out;
			if (ret) {
				ret = get_cur_path(sctx, un->val, un->aux,
						valid_path);
				if (ret < 0)
					goto out;
				ret = send_rmdir(sctx, valid_path);
				if (ret < 0)
					goto out;
			}
		}
	}

	ret = 0;

out:
	free_recorded_refs(sctx);
	ulist_free(check_dirs);
	fs_path_free(sctx, valid_path);
	return ret;
}

static int __record_new_ref(int num, u64 dir, int index,
			    struct fs_path *name,
			    void *ctx)
{
	int ret = 0;
	struct send_ctx *sctx = ctx;
	struct fs_path *p;
	u64 gen;

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	ret = get_inode_info(sctx->send_root, dir, NULL, &gen, NULL, NULL,
3007
			NULL, NULL);
3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039
	if (ret < 0)
		goto out;

	ret = get_cur_path(sctx, dir, gen, p);
	if (ret < 0)
		goto out;
	ret = fs_path_add_path(p, name);
	if (ret < 0)
		goto out;

	ret = record_ref(&sctx->new_refs, dir, gen, p);

out:
	if (ret)
		fs_path_free(sctx, p);
	return ret;
}

static int __record_deleted_ref(int num, u64 dir, int index,
				struct fs_path *name,
				void *ctx)
{
	int ret = 0;
	struct send_ctx *sctx = ctx;
	struct fs_path *p;
	u64 gen;

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL, NULL,
3040
			NULL, NULL);
3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216
	if (ret < 0)
		goto out;

	ret = get_cur_path(sctx, dir, gen, p);
	if (ret < 0)
		goto out;
	ret = fs_path_add_path(p, name);
	if (ret < 0)
		goto out;

	ret = record_ref(&sctx->deleted_refs, dir, gen, p);

out:
	if (ret)
		fs_path_free(sctx, p);
	return ret;
}

static int record_new_ref(struct send_ctx *sctx)
{
	int ret;

	ret = iterate_inode_ref(sctx, sctx->send_root, sctx->left_path,
			sctx->cmp_key, 0, __record_new_ref, sctx);
	if (ret < 0)
		goto out;
	ret = 0;

out:
	return ret;
}

static int record_deleted_ref(struct send_ctx *sctx)
{
	int ret;

	ret = iterate_inode_ref(sctx, sctx->parent_root, sctx->right_path,
			sctx->cmp_key, 0, __record_deleted_ref, sctx);
	if (ret < 0)
		goto out;
	ret = 0;

out:
	return ret;
}

struct find_ref_ctx {
	u64 dir;
	struct fs_path *name;
	int found_idx;
};

static int __find_iref(int num, u64 dir, int index,
		       struct fs_path *name,
		       void *ctx_)
{
	struct find_ref_ctx *ctx = ctx_;

	if (dir == ctx->dir && fs_path_len(name) == fs_path_len(ctx->name) &&
	    strncmp(name->start, ctx->name->start, fs_path_len(name)) == 0) {
		ctx->found_idx = num;
		return 1;
	}
	return 0;
}

static int find_iref(struct send_ctx *sctx,
		     struct btrfs_root *root,
		     struct btrfs_path *path,
		     struct btrfs_key *key,
		     u64 dir, struct fs_path *name)
{
	int ret;
	struct find_ref_ctx ctx;

	ctx.dir = dir;
	ctx.name = name;
	ctx.found_idx = -1;

	ret = iterate_inode_ref(sctx, root, path, key, 0, __find_iref, &ctx);
	if (ret < 0)
		return ret;

	if (ctx.found_idx == -1)
		return -ENOENT;

	return ctx.found_idx;
}

static int __record_changed_new_ref(int num, u64 dir, int index,
				    struct fs_path *name,
				    void *ctx)
{
	int ret;
	struct send_ctx *sctx = ctx;

	ret = find_iref(sctx, sctx->parent_root, sctx->right_path,
			sctx->cmp_key, dir, name);
	if (ret == -ENOENT)
		ret = __record_new_ref(num, dir, index, name, sctx);
	else if (ret > 0)
		ret = 0;

	return ret;
}

static int __record_changed_deleted_ref(int num, u64 dir, int index,
					struct fs_path *name,
					void *ctx)
{
	int ret;
	struct send_ctx *sctx = ctx;

	ret = find_iref(sctx, sctx->send_root, sctx->left_path, sctx->cmp_key,
			dir, name);
	if (ret == -ENOENT)
		ret = __record_deleted_ref(num, dir, index, name, sctx);
	else if (ret > 0)
		ret = 0;

	return ret;
}

static int record_changed_ref(struct send_ctx *sctx)
{
	int ret = 0;

	ret = iterate_inode_ref(sctx, sctx->send_root, sctx->left_path,
			sctx->cmp_key, 0, __record_changed_new_ref, sctx);
	if (ret < 0)
		goto out;
	ret = iterate_inode_ref(sctx, sctx->parent_root, sctx->right_path,
			sctx->cmp_key, 0, __record_changed_deleted_ref, sctx);
	if (ret < 0)
		goto out;
	ret = 0;

out:
	return ret;
}

/*
 * Record and process all refs at once. Needed when an inode changes the
 * generation number, which means that it was deleted and recreated.
 */
static int process_all_refs(struct send_ctx *sctx,
			    enum btrfs_compare_tree_result cmd)
{
	int ret;
	struct btrfs_root *root;
	struct btrfs_path *path;
	struct btrfs_key key;
	struct btrfs_key found_key;
	struct extent_buffer *eb;
	int slot;
	iterate_inode_ref_t cb;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	if (cmd == BTRFS_COMPARE_TREE_NEW) {
		root = sctx->send_root;
		cb = __record_new_ref;
	} else if (cmd == BTRFS_COMPARE_TREE_DELETED) {
		root = sctx->parent_root;
		cb = __record_deleted_ref;
	} else {
		BUG();
	}

	key.objectid = sctx->cmp_key->objectid;
	key.type = BTRFS_INODE_REF_KEY;
	key.offset = 0;
	while (1) {
		ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
3217
		if (ret < 0)
3218
			goto out;
3219
		if (ret)
3220 3221 3222 3223 3224 3225 3226
			break;

		eb = path->nodes[0];
		slot = path->slots[0];
		btrfs_item_key_to_cpu(eb, &found_key, slot);

		if (found_key.objectid != key.objectid ||
3227
		    found_key.type != key.type)
3228 3229
			break;

3230 3231
		ret = iterate_inode_ref(sctx, root, path, &found_key, 0, cb,
				sctx);
3232 3233 3234 3235 3236 3237
		btrfs_release_path(path);
		if (ret < 0)
			goto out;

		key.offset = found_key.offset + 1;
	}
3238
	btrfs_release_path(path);
3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560

	ret = process_recorded_refs(sctx);

out:
	btrfs_free_path(path);
	return ret;
}

static int send_set_xattr(struct send_ctx *sctx,
			  struct fs_path *path,
			  const char *name, int name_len,
			  const char *data, int data_len)
{
	int ret = 0;

	ret = begin_cmd(sctx, BTRFS_SEND_C_SET_XATTR);
	if (ret < 0)
		goto out;

	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
	TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);
	TLV_PUT(sctx, BTRFS_SEND_A_XATTR_DATA, data, data_len);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	return ret;
}

static int send_remove_xattr(struct send_ctx *sctx,
			  struct fs_path *path,
			  const char *name, int name_len)
{
	int ret = 0;

	ret = begin_cmd(sctx, BTRFS_SEND_C_REMOVE_XATTR);
	if (ret < 0)
		goto out;

	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path);
	TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	return ret;
}

static int __process_new_xattr(int num, struct btrfs_key *di_key,
			       const char *name, int name_len,
			       const char *data, int data_len,
			       u8 type, void *ctx)
{
	int ret;
	struct send_ctx *sctx = ctx;
	struct fs_path *p;
	posix_acl_xattr_header dummy_acl;

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	/*
	 * This hack is needed because empty acl's are stored as zero byte
	 * data in xattrs. Problem with that is, that receiving these zero byte
	 * acl's will fail later. To fix this, we send a dummy acl list that
	 * only contains the version number and no entries.
	 */
	if (!strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS, name_len) ||
	    !strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT, name_len)) {
		if (data_len == 0) {
			dummy_acl.a_version =
					cpu_to_le32(POSIX_ACL_XATTR_VERSION);
			data = (char *)&dummy_acl;
			data_len = sizeof(dummy_acl);
		}
	}

	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
	if (ret < 0)
		goto out;

	ret = send_set_xattr(sctx, p, name, name_len, data, data_len);

out:
	fs_path_free(sctx, p);
	return ret;
}

static int __process_deleted_xattr(int num, struct btrfs_key *di_key,
				   const char *name, int name_len,
				   const char *data, int data_len,
				   u8 type, void *ctx)
{
	int ret;
	struct send_ctx *sctx = ctx;
	struct fs_path *p;

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
	if (ret < 0)
		goto out;

	ret = send_remove_xattr(sctx, p, name, name_len);

out:
	fs_path_free(sctx, p);
	return ret;
}

static int process_new_xattr(struct send_ctx *sctx)
{
	int ret = 0;

	ret = iterate_dir_item(sctx, sctx->send_root, sctx->left_path,
			sctx->cmp_key, __process_new_xattr, sctx);

	return ret;
}

static int process_deleted_xattr(struct send_ctx *sctx)
{
	int ret;

	ret = iterate_dir_item(sctx, sctx->parent_root, sctx->right_path,
			sctx->cmp_key, __process_deleted_xattr, sctx);

	return ret;
}

struct find_xattr_ctx {
	const char *name;
	int name_len;
	int found_idx;
	char *found_data;
	int found_data_len;
};

static int __find_xattr(int num, struct btrfs_key *di_key,
			const char *name, int name_len,
			const char *data, int data_len,
			u8 type, void *vctx)
{
	struct find_xattr_ctx *ctx = vctx;

	if (name_len == ctx->name_len &&
	    strncmp(name, ctx->name, name_len) == 0) {
		ctx->found_idx = num;
		ctx->found_data_len = data_len;
		ctx->found_data = kmalloc(data_len, GFP_NOFS);
		if (!ctx->found_data)
			return -ENOMEM;
		memcpy(ctx->found_data, data, data_len);
		return 1;
	}
	return 0;
}

static int find_xattr(struct send_ctx *sctx,
		      struct btrfs_root *root,
		      struct btrfs_path *path,
		      struct btrfs_key *key,
		      const char *name, int name_len,
		      char **data, int *data_len)
{
	int ret;
	struct find_xattr_ctx ctx;

	ctx.name = name;
	ctx.name_len = name_len;
	ctx.found_idx = -1;
	ctx.found_data = NULL;
	ctx.found_data_len = 0;

	ret = iterate_dir_item(sctx, root, path, key, __find_xattr, &ctx);
	if (ret < 0)
		return ret;

	if (ctx.found_idx == -1)
		return -ENOENT;
	if (data) {
		*data = ctx.found_data;
		*data_len = ctx.found_data_len;
	} else {
		kfree(ctx.found_data);
	}
	return ctx.found_idx;
}


static int __process_changed_new_xattr(int num, struct btrfs_key *di_key,
				       const char *name, int name_len,
				       const char *data, int data_len,
				       u8 type, void *ctx)
{
	int ret;
	struct send_ctx *sctx = ctx;
	char *found_data = NULL;
	int found_data_len  = 0;
	struct fs_path *p = NULL;

	ret = find_xattr(sctx, sctx->parent_root, sctx->right_path,
			sctx->cmp_key, name, name_len, &found_data,
			&found_data_len);
	if (ret == -ENOENT) {
		ret = __process_new_xattr(num, di_key, name, name_len, data,
				data_len, type, ctx);
	} else if (ret >= 0) {
		if (data_len != found_data_len ||
		    memcmp(data, found_data, data_len)) {
			ret = __process_new_xattr(num, di_key, name, name_len,
					data, data_len, type, ctx);
		} else {
			ret = 0;
		}
	}

	kfree(found_data);
	fs_path_free(sctx, p);
	return ret;
}

static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key,
					   const char *name, int name_len,
					   const char *data, int data_len,
					   u8 type, void *ctx)
{
	int ret;
	struct send_ctx *sctx = ctx;

	ret = find_xattr(sctx, sctx->send_root, sctx->left_path, sctx->cmp_key,
			name, name_len, NULL, NULL);
	if (ret == -ENOENT)
		ret = __process_deleted_xattr(num, di_key, name, name_len, data,
				data_len, type, ctx);
	else if (ret >= 0)
		ret = 0;

	return ret;
}

static int process_changed_xattr(struct send_ctx *sctx)
{
	int ret = 0;

	ret = iterate_dir_item(sctx, sctx->send_root, sctx->left_path,
			sctx->cmp_key, __process_changed_new_xattr, sctx);
	if (ret < 0)
		goto out;
	ret = iterate_dir_item(sctx, sctx->parent_root, sctx->right_path,
			sctx->cmp_key, __process_changed_deleted_xattr, sctx);

out:
	return ret;
}

static int process_all_new_xattrs(struct send_ctx *sctx)
{
	int ret;
	struct btrfs_root *root;
	struct btrfs_path *path;
	struct btrfs_key key;
	struct btrfs_key found_key;
	struct extent_buffer *eb;
	int slot;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	root = sctx->send_root;

	key.objectid = sctx->cmp_key->objectid;
	key.type = BTRFS_XATTR_ITEM_KEY;
	key.offset = 0;
	while (1) {
		ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
		if (ret < 0)
			goto out;
		if (ret) {
			ret = 0;
			goto out;
		}

		eb = path->nodes[0];
		slot = path->slots[0];
		btrfs_item_key_to_cpu(eb, &found_key, slot);

		if (found_key.objectid != key.objectid ||
		    found_key.type != key.type) {
			ret = 0;
			goto out;
		}

		ret = iterate_dir_item(sctx, root, path, &found_key,
				__process_new_xattr, sctx);
		if (ret < 0)
			goto out;

		btrfs_release_path(path);
		key.offset = found_key.offset + 1;
	}

out:
	btrfs_free_path(path);
	return ret;
}

/*
 * Read some bytes from the current inode/file and send a write command to
 * user space.
 */
static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
{
	int ret = 0;
	struct fs_path *p;
	loff_t pos = offset;
3561
	int num_read = 0;
3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585
	mm_segment_t old_fs;

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	/*
	 * vfs normally only accepts user space buffers for security reasons.
	 * we only read from the file and also only provide the read_buf buffer
	 * to vfs. As this buffer does not come from a user space call, it's
	 * ok to temporary allow kernel space buffers.
	 */
	old_fs = get_fs();
	set_fs(KERNEL_DS);

verbose_printk("btrfs: send_write offset=%llu, len=%d\n", offset, len);

	ret = open_cur_inode_file(sctx);
	if (ret < 0)
		goto out;

	ret = vfs_read(sctx->cur_inode_filp, sctx->read_buf, len, &pos);
	if (ret < 0)
		goto out;
3586 3587
	num_read = ret;
	if (!num_read)
3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599
		goto out;

	ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
	if (ret < 0)
		goto out;

	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
	if (ret < 0)
		goto out;

	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
3600
	TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, num_read);
3601 3602 3603 3604 3605 3606 3607 3608 3609

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	fs_path_free(sctx, p);
	set_fs(old_fs);
	if (ret < 0)
		return ret;
3610
	return num_read;
3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644
}

/*
 * Send a clone command to user space.
 */
static int send_clone(struct send_ctx *sctx,
		      u64 offset, u32 len,
		      struct clone_root *clone_root)
{
	int ret = 0;
	struct fs_path *p;
	u64 gen;

verbose_printk("btrfs: send_clone offset=%llu, len=%d, clone_root=%llu, "
	       "clone_inode=%llu, clone_offset=%llu\n", offset, len,
		clone_root->root->objectid, clone_root->ino,
		clone_root->offset);

	p = fs_path_alloc(sctx);
	if (!p)
		return -ENOMEM;

	ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE);
	if (ret < 0)
		goto out;

	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
	if (ret < 0)
		goto out;

	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
	TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len);
	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);

3645
	if (clone_root->root == sctx->send_root) {
3646
		ret = get_inode_info(sctx->send_root, clone_root->ino, NULL,
3647
				&gen, NULL, NULL, NULL, NULL);
3648 3649 3650 3651
		if (ret < 0)
			goto out;
		ret = get_cur_path(sctx, clone_root->ino, gen, p);
	} else {
3652 3653
		ret = get_inode_path(sctx, clone_root->root,
				clone_root->ino, p);
3654 3655 3656 3657 3658
	}
	if (ret < 0)
		goto out;

	TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
3659
			clone_root->root->root_item.uuid);
3660
	TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
3661
			clone_root->root->root_item.ctransid);
3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689
	TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p);
	TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET,
			clone_root->offset);

	ret = send_cmd(sctx);

tlv_put_failure:
out:
	fs_path_free(sctx, p);
	return ret;
}

static int send_write_or_clone(struct send_ctx *sctx,
			       struct btrfs_path *path,
			       struct btrfs_key *key,
			       struct clone_root *clone_root)
{
	int ret = 0;
	struct btrfs_file_extent_item *ei;
	u64 offset = key->offset;
	u64 pos = 0;
	u64 len;
	u32 l;
	u8 type;

	ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
			struct btrfs_file_extent_item);
	type = btrfs_file_extent_type(path->nodes[0], ei);
3690
	if (type == BTRFS_FILE_EXTENT_INLINE) {
3691
		len = btrfs_file_extent_inline_len(path->nodes[0], ei);
3692 3693 3694 3695 3696 3697 3698
		/*
		 * it is possible the inline item won't cover the whole page,
		 * but there may be items after this page.  Make
		 * sure to send the whole thing
		 */
		len = PAGE_CACHE_ALIGN(len);
	} else {
3699
		len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
3700
	}
3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747

	if (offset + len > sctx->cur_inode_size)
		len = sctx->cur_inode_size - offset;
	if (len == 0) {
		ret = 0;
		goto out;
	}

	if (!clone_root) {
		while (pos < len) {
			l = len - pos;
			if (l > BTRFS_SEND_READ_SIZE)
				l = BTRFS_SEND_READ_SIZE;
			ret = send_write(sctx, pos + offset, l);
			if (ret < 0)
				goto out;
			if (!ret)
				break;
			pos += ret;
		}
		ret = 0;
	} else {
		ret = send_clone(sctx, offset, len, clone_root);
	}

out:
	return ret;
}

static int is_extent_unchanged(struct send_ctx *sctx,
			       struct btrfs_path *left_path,
			       struct btrfs_key *ekey)
{
	int ret = 0;
	struct btrfs_key key;
	struct btrfs_path *path = NULL;
	struct extent_buffer *eb;
	int slot;
	struct btrfs_key found_key;
	struct btrfs_file_extent_item *ei;
	u64 left_disknr;
	u64 right_disknr;
	u64 left_offset;
	u64 right_offset;
	u64 left_offset_fixed;
	u64 left_len;
	u64 right_len;
3748 3749
	u64 left_gen;
	u64 right_gen;
3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765
	u8 left_type;
	u8 right_type;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	eb = left_path->nodes[0];
	slot = left_path->slots[0];
	ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
	left_type = btrfs_file_extent_type(eb, ei);

	if (left_type != BTRFS_FILE_EXTENT_REG) {
		ret = 0;
		goto out;
	}
3766 3767 3768 3769
	left_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
	left_len = btrfs_file_extent_num_bytes(eb, ei);
	left_offset = btrfs_file_extent_offset(eb, ei);
	left_gen = btrfs_file_extent_generation(eb, ei);
3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824

	/*
	 * Following comments will refer to these graphics. L is the left
	 * extents which we are checking at the moment. 1-8 are the right
	 * extents that we iterate.
	 *
	 *       |-----L-----|
	 * |-1-|-2a-|-3-|-4-|-5-|-6-|
	 *
	 *       |-----L-----|
	 * |--1--|-2b-|...(same as above)
	 *
	 * Alternative situation. Happens on files where extents got split.
	 *       |-----L-----|
	 * |-----------7-----------|-6-|
	 *
	 * Alternative situation. Happens on files which got larger.
	 *       |-----L-----|
	 * |-8-|
	 * Nothing follows after 8.
	 */

	key.objectid = ekey->objectid;
	key.type = BTRFS_EXTENT_DATA_KEY;
	key.offset = ekey->offset;
	ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0);
	if (ret < 0)
		goto out;
	if (ret) {
		ret = 0;
		goto out;
	}

	/*
	 * Handle special case where the right side has no extents at all.
	 */
	eb = path->nodes[0];
	slot = path->slots[0];
	btrfs_item_key_to_cpu(eb, &found_key, slot);
	if (found_key.objectid != key.objectid ||
	    found_key.type != key.type) {
		ret = 0;
		goto out;
	}

	/*
	 * We're now on 2a, 2b or 7.
	 */
	key = found_key;
	while (key.offset < ekey->offset + left_len) {
		ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
		right_type = btrfs_file_extent_type(eb, ei);
		right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
		right_len = btrfs_file_extent_num_bytes(eb, ei);
		right_offset = btrfs_file_extent_offset(eb, ei);
3825
		right_gen = btrfs_file_extent_generation(eb, ei);
3826 3827 3828 3829 3830 3831 3832 3833 3834 3835

		if (right_type != BTRFS_FILE_EXTENT_REG) {
			ret = 0;
			goto out;
		}

		/*
		 * Are we at extent 8? If yes, we know the extent is changed.
		 * This may only happen on the first iteration.
		 */
3836
		if (found_key.offset + right_len <= ekey->offset) {
3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852
			ret = 0;
			goto out;
		}

		left_offset_fixed = left_offset;
		if (key.offset < ekey->offset) {
			/* Fix the right offset for 2a and 7. */
			right_offset += ekey->offset - key.offset;
		} else {
			/* Fix the left offset for all behind 2a and 2b */
			left_offset_fixed += key.offset - ekey->offset;
		}

		/*
		 * Check if we have the same extent.
		 */
3853
		if (left_disknr != right_disknr ||
3854 3855
		    left_offset_fixed != right_offset ||
		    left_gen != right_gen) {
3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993
			ret = 0;
			goto out;
		}

		/*
		 * Go to the next extent.
		 */
		ret = btrfs_next_item(sctx->parent_root, path);
		if (ret < 0)
			goto out;
		if (!ret) {
			eb = path->nodes[0];
			slot = path->slots[0];
			btrfs_item_key_to_cpu(eb, &found_key, slot);
		}
		if (ret || found_key.objectid != key.objectid ||
		    found_key.type != key.type) {
			key.offset += right_len;
			break;
		} else {
			if (found_key.offset != key.offset + right_len) {
				/* Should really not happen */
				ret = -EIO;
				goto out;
			}
		}
		key = found_key;
	}

	/*
	 * We're now behind the left extent (treat as unchanged) or at the end
	 * of the right side (treat as changed).
	 */
	if (key.offset >= ekey->offset + left_len)
		ret = 1;
	else
		ret = 0;


out:
	btrfs_free_path(path);
	return ret;
}

static int process_extent(struct send_ctx *sctx,
			  struct btrfs_path *path,
			  struct btrfs_key *key)
{
	int ret = 0;
	struct clone_root *found_clone = NULL;

	if (S_ISLNK(sctx->cur_inode_mode))
		return 0;

	if (sctx->parent_root && !sctx->cur_inode_new) {
		ret = is_extent_unchanged(sctx, path, key);
		if (ret < 0)
			goto out;
		if (ret) {
			ret = 0;
			goto out;
		}
	}

	ret = find_extent_clone(sctx, path, key->objectid, key->offset,
			sctx->cur_inode_size, &found_clone);
	if (ret != -ENOENT && ret < 0)
		goto out;

	ret = send_write_or_clone(sctx, path, key, found_clone);

out:
	return ret;
}

static int process_all_extents(struct send_ctx *sctx)
{
	int ret;
	struct btrfs_root *root;
	struct btrfs_path *path;
	struct btrfs_key key;
	struct btrfs_key found_key;
	struct extent_buffer *eb;
	int slot;

	root = sctx->send_root;
	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	key.objectid = sctx->cmp_key->objectid;
	key.type = BTRFS_EXTENT_DATA_KEY;
	key.offset = 0;
	while (1) {
		ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
		if (ret < 0)
			goto out;
		if (ret) {
			ret = 0;
			goto out;
		}

		eb = path->nodes[0];
		slot = path->slots[0];
		btrfs_item_key_to_cpu(eb, &found_key, slot);

		if (found_key.objectid != key.objectid ||
		    found_key.type != key.type) {
			ret = 0;
			goto out;
		}

		ret = process_extent(sctx, path, &found_key);
		if (ret < 0)
			goto out;

		btrfs_release_path(path);
		key.offset = found_key.offset + 1;
	}

out:
	btrfs_free_path(path);
	return ret;
}

static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end)
{
	int ret = 0;

	if (sctx->cur_ino == 0)
		goto out;
	if (!at_end && sctx->cur_ino == sctx->cmp_key->objectid &&
	    sctx->cmp_key->type <= BTRFS_INODE_REF_KEY)
		goto out;
	if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs))
		goto out;

	ret = process_recorded_refs(sctx);
3994 3995 3996 3997 3998 3999 4000 4001 4002
	if (ret < 0)
		goto out;

	/*
	 * We have processed the refs and thus need to advance send_progress.
	 * Now, calls to get_cur_xxx will take the updated refs of the current
	 * inode into account.
	 */
	sctx->send_progress = sctx->cur_ino + 1;
4003 4004 4005 4006 4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029

out:
	return ret;
}

static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
{
	int ret = 0;
	u64 left_mode;
	u64 left_uid;
	u64 left_gid;
	u64 right_mode;
	u64 right_uid;
	u64 right_gid;
	int need_chmod = 0;
	int need_chown = 0;

	ret = process_recorded_refs_if_needed(sctx, at_end);
	if (ret < 0)
		goto out;

	if (sctx->cur_ino == 0 || sctx->cur_inode_deleted)
		goto out;
	if (!at_end && sctx->cmp_key->objectid == sctx->cur_ino)
		goto out;

	ret = get_inode_info(sctx->send_root, sctx->cur_ino, NULL, NULL,
4030
			&left_mode, &left_uid, &left_gid, NULL);
4031 4032 4033 4034 4035 4036 4037 4038 4039 4040
	if (ret < 0)
		goto out;

	if (!S_ISLNK(sctx->cur_inode_mode)) {
		if (!sctx->parent_root || sctx->cur_inode_new) {
			need_chmod = 1;
			need_chown = 1;
		} else {
			ret = get_inode_info(sctx->parent_root, sctx->cur_ino,
					NULL, NULL, &right_mode, &right_uid,
4041
					&right_gid, NULL);
4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099
			if (ret < 0)
				goto out;

			if (left_uid != right_uid || left_gid != right_gid)
				need_chown = 1;
			if (left_mode != right_mode)
				need_chmod = 1;
		}
	}

	if (S_ISREG(sctx->cur_inode_mode)) {
		ret = send_truncate(sctx, sctx->cur_ino, sctx->cur_inode_gen,
				sctx->cur_inode_size);
		if (ret < 0)
			goto out;
	}

	if (need_chown) {
		ret = send_chown(sctx, sctx->cur_ino, sctx->cur_inode_gen,
				left_uid, left_gid);
		if (ret < 0)
			goto out;
	}
	if (need_chmod) {
		ret = send_chmod(sctx, sctx->cur_ino, sctx->cur_inode_gen,
				left_mode);
		if (ret < 0)
			goto out;
	}

	/*
	 * Need to send that every time, no matter if it actually changed
	 * between the two trees as we have done changes to the inode before.
	 */
	ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen);
	if (ret < 0)
		goto out;

out:
	return ret;
}

static int changed_inode(struct send_ctx *sctx,
			 enum btrfs_compare_tree_result result)
{
	int ret = 0;
	struct btrfs_key *key = sctx->cmp_key;
	struct btrfs_inode_item *left_ii = NULL;
	struct btrfs_inode_item *right_ii = NULL;
	u64 left_gen = 0;
	u64 right_gen = 0;

	ret = close_cur_inode_file(sctx);
	if (ret < 0)
		goto out;

	sctx->cur_ino = key->objectid;
	sctx->cur_inode_new_gen = 0;
4100 4101 4102 4103 4104 4105

	/*
	 * Set send_progress to current inode. This will tell all get_cur_xxx
	 * functions that the current inode's refs are not updated yet. Later,
	 * when process_recorded_refs is finished, it is set to cur_ino + 1.
	 */
4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128
	sctx->send_progress = sctx->cur_ino;

	if (result == BTRFS_COMPARE_TREE_NEW ||
	    result == BTRFS_COMPARE_TREE_CHANGED) {
		left_ii = btrfs_item_ptr(sctx->left_path->nodes[0],
				sctx->left_path->slots[0],
				struct btrfs_inode_item);
		left_gen = btrfs_inode_generation(sctx->left_path->nodes[0],
				left_ii);
	} else {
		right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
				sctx->right_path->slots[0],
				struct btrfs_inode_item);
		right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
				right_ii);
	}
	if (result == BTRFS_COMPARE_TREE_CHANGED) {
		right_ii = btrfs_item_ptr(sctx->right_path->nodes[0],
				sctx->right_path->slots[0],
				struct btrfs_inode_item);

		right_gen = btrfs_inode_generation(sctx->right_path->nodes[0],
				right_ii);
4129 4130 4131 4132 4133 4134 4135 4136

		/*
		 * The cur_ino = root dir case is special here. We can't treat
		 * the inode as deleted+reused because it would generate a
		 * stream that tries to delete/mkdir the root dir.
		 */
		if (left_gen != right_gen &&
		    sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148
			sctx->cur_inode_new_gen = 1;
	}

	if (result == BTRFS_COMPARE_TREE_NEW) {
		sctx->cur_inode_gen = left_gen;
		sctx->cur_inode_new = 1;
		sctx->cur_inode_deleted = 0;
		sctx->cur_inode_size = btrfs_inode_size(
				sctx->left_path->nodes[0], left_ii);
		sctx->cur_inode_mode = btrfs_inode_mode(
				sctx->left_path->nodes[0], left_ii);
		if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
4149
			ret = send_create_inode_if_needed(sctx);
4150 4151 4152 4153 4154 4155 4156 4157 4158
	} else if (result == BTRFS_COMPARE_TREE_DELETED) {
		sctx->cur_inode_gen = right_gen;
		sctx->cur_inode_new = 0;
		sctx->cur_inode_deleted = 1;
		sctx->cur_inode_size = btrfs_inode_size(
				sctx->right_path->nodes[0], right_ii);
		sctx->cur_inode_mode = btrfs_inode_mode(
				sctx->right_path->nodes[0], right_ii);
	} else if (result == BTRFS_COMPARE_TREE_CHANGED) {
4159 4160 4161 4162 4163 4164 4165
		/*
		 * We need to do some special handling in case the inode was
		 * reported as changed with a changed generation number. This
		 * means that the original inode was deleted and new inode
		 * reused the same inum. So we have to treat the old inode as
		 * deleted and the new one as new.
		 */
4166
		if (sctx->cur_inode_new_gen) {
4167 4168 4169
			/*
			 * First, process the inode as if it was deleted.
			 */
4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181
			sctx->cur_inode_gen = right_gen;
			sctx->cur_inode_new = 0;
			sctx->cur_inode_deleted = 1;
			sctx->cur_inode_size = btrfs_inode_size(
					sctx->right_path->nodes[0], right_ii);
			sctx->cur_inode_mode = btrfs_inode_mode(
					sctx->right_path->nodes[0], right_ii);
			ret = process_all_refs(sctx,
					BTRFS_COMPARE_TREE_DELETED);
			if (ret < 0)
				goto out;

4182 4183 4184
			/*
			 * Now process the inode as if it was new.
			 */
4185 4186 4187 4188 4189 4190 4191
			sctx->cur_inode_gen = left_gen;
			sctx->cur_inode_new = 1;
			sctx->cur_inode_deleted = 0;
			sctx->cur_inode_size = btrfs_inode_size(
					sctx->left_path->nodes[0], left_ii);
			sctx->cur_inode_mode = btrfs_inode_mode(
					sctx->left_path->nodes[0], left_ii);
4192
			ret = send_create_inode_if_needed(sctx);
4193 4194 4195 4196 4197 4198
			if (ret < 0)
				goto out;

			ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW);
			if (ret < 0)
				goto out;
4199 4200 4201 4202 4203
			/*
			 * Advance send_progress now as we did not get into
			 * process_recorded_refs_if_needed in the new_gen case.
			 */
			sctx->send_progress = sctx->cur_ino + 1;
4204 4205 4206 4207 4208

			/*
			 * Now process all extents and xattrs of the inode as if
			 * they were all new.
			 */
4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230
			ret = process_all_extents(sctx);
			if (ret < 0)
				goto out;
			ret = process_all_new_xattrs(sctx);
			if (ret < 0)
				goto out;
		} else {
			sctx->cur_inode_gen = left_gen;
			sctx->cur_inode_new = 0;
			sctx->cur_inode_new_gen = 0;
			sctx->cur_inode_deleted = 0;
			sctx->cur_inode_size = btrfs_inode_size(
					sctx->left_path->nodes[0], left_ii);
			sctx->cur_inode_mode = btrfs_inode_mode(
					sctx->left_path->nodes[0], left_ii);
		}
	}

out:
	return ret;
}

4231 4232 4233 4234 4235 4236 4237 4238 4239 4240
/*
 * We have to process new refs before deleted refs, but compare_trees gives us
 * the new and deleted refs mixed. To fix this, we record the new/deleted refs
 * first and later process them in process_recorded_refs.
 * For the cur_inode_new_gen case, we skip recording completely because
 * changed_inode did already initiate processing of refs. The reason for this is
 * that in this case, compare_tree actually compares the refs of 2 different
 * inodes. To fix this, process_all_refs is used in changed_inode to handle all
 * refs of the right tree as deleted and all refs of the left tree as new.
 */
4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260
static int changed_ref(struct send_ctx *sctx,
		       enum btrfs_compare_tree_result result)
{
	int ret = 0;

	BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);

	if (!sctx->cur_inode_new_gen &&
	    sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) {
		if (result == BTRFS_COMPARE_TREE_NEW)
			ret = record_new_ref(sctx);
		else if (result == BTRFS_COMPARE_TREE_DELETED)
			ret = record_deleted_ref(sctx);
		else if (result == BTRFS_COMPARE_TREE_CHANGED)
			ret = record_changed_ref(sctx);
	}

	return ret;
}

4261 4262 4263 4264 4265
/*
 * Process new/deleted/changed xattrs. We skip processing in the
 * cur_inode_new_gen case because changed_inode did already initiate processing
 * of xattrs. The reason is the same as in changed_ref
 */
4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284
static int changed_xattr(struct send_ctx *sctx,
			 enum btrfs_compare_tree_result result)
{
	int ret = 0;

	BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);

	if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
		if (result == BTRFS_COMPARE_TREE_NEW)
			ret = process_new_xattr(sctx);
		else if (result == BTRFS_COMPARE_TREE_DELETED)
			ret = process_deleted_xattr(sctx);
		else if (result == BTRFS_COMPARE_TREE_CHANGED)
			ret = process_changed_xattr(sctx);
	}

	return ret;
}

4285 4286 4287 4288 4289
/*
 * Process new/deleted/changed extents. We skip processing in the
 * cur_inode_new_gen case because changed_inode did already initiate processing
 * of extents. The reason is the same as in changed_ref
 */
4290 4291 4292 4293 4294 4295 4296 4297 4298 4299 4300 4301 4302 4303 4304 4305
static int changed_extent(struct send_ctx *sctx,
			  enum btrfs_compare_tree_result result)
{
	int ret = 0;

	BUG_ON(sctx->cur_ino != sctx->cmp_key->objectid);

	if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) {
		if (result != BTRFS_COMPARE_TREE_DELETED)
			ret = process_extent(sctx, sctx->left_path,
					sctx->cmp_key);
	}

	return ret;
}

4306 4307 4308 4309
/*
 * Updates compare related fields in sctx and simply forwards to the actual
 * changed_xxx functions.
 */
4310 4311 4312 4313 4314 4315 4316 4317 4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328
static int changed_cb(struct btrfs_root *left_root,
		      struct btrfs_root *right_root,
		      struct btrfs_path *left_path,
		      struct btrfs_path *right_path,
		      struct btrfs_key *key,
		      enum btrfs_compare_tree_result result,
		      void *ctx)
{
	int ret = 0;
	struct send_ctx *sctx = ctx;

	sctx->left_path = left_path;
	sctx->right_path = right_path;
	sctx->cmp_key = key;

	ret = finish_inode_if_needed(sctx, 0);
	if (ret < 0)
		goto out;

4329 4330 4331 4332 4333
	/* Ignore non-FS objects */
	if (key->objectid == BTRFS_FREE_INO_OBJECTID ||
	    key->objectid == BTRFS_FREE_SPACE_OBJECTID)
		goto out;

4334 4335 4336 4337 4338 4339 4340 4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362 4363 4364 4365 4366 4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385
	if (key->type == BTRFS_INODE_ITEM_KEY)
		ret = changed_inode(sctx, result);
	else if (key->type == BTRFS_INODE_REF_KEY)
		ret = changed_ref(sctx, result);
	else if (key->type == BTRFS_XATTR_ITEM_KEY)
		ret = changed_xattr(sctx, result);
	else if (key->type == BTRFS_EXTENT_DATA_KEY)
		ret = changed_extent(sctx, result);

out:
	return ret;
}

static int full_send_tree(struct send_ctx *sctx)
{
	int ret;
	struct btrfs_trans_handle *trans = NULL;
	struct btrfs_root *send_root = sctx->send_root;
	struct btrfs_key key;
	struct btrfs_key found_key;
	struct btrfs_path *path;
	struct extent_buffer *eb;
	int slot;
	u64 start_ctransid;
	u64 ctransid;

	path = alloc_path_for_send();
	if (!path)
		return -ENOMEM;

	spin_lock(&send_root->root_times_lock);
	start_ctransid = btrfs_root_ctransid(&send_root->root_item);
	spin_unlock(&send_root->root_times_lock);

	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;

join_trans:
	/*
	 * We need to make sure the transaction does not get committed
	 * while we do anything on commit roots. Join a transaction to prevent
	 * this.
	 */
	trans = btrfs_join_transaction(send_root);
	if (IS_ERR(trans)) {
		ret = PTR_ERR(trans);
		trans = NULL;
		goto out;
	}

	/*
4386 4387
	 * Make sure the tree has not changed after re-joining. We detect this
	 * by comparing start_ctransid and ctransid. They should always match.
4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409 4410 4411 4412 4413 4414 4415 4416 4417 4418 4419 4420 4421 4422 4423 4424 4425 4426 4427 4428 4429 4430 4431 4432 4433 4434 4435 4436 4437 4438 4439 4440 4441 4442 4443 4444 4445 4446 4447 4448 4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464 4465 4466 4467 4468 4469 4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491 4492 4493 4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504 4505 4506 4507 4508 4509 4510 4511 4512 4513 4514 4515 4516 4517 4518 4519 4520 4521 4522 4523 4524 4525 4526 4527 4528 4529 4530 4531 4532 4533 4534 4535 4536 4537 4538 4539 4540 4541 4542 4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651 4652 4653 4654 4655 4656 4657
	 */
	spin_lock(&send_root->root_times_lock);
	ctransid = btrfs_root_ctransid(&send_root->root_item);
	spin_unlock(&send_root->root_times_lock);

	if (ctransid != start_ctransid) {
		WARN(1, KERN_WARNING "btrfs: the root that you're trying to "
				     "send was modified in between. This is "
				     "probably a bug.\n");
		ret = -EIO;
		goto out;
	}

	ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0);
	if (ret < 0)
		goto out;
	if (ret)
		goto out_finish;

	while (1) {
		/*
		 * When someone want to commit while we iterate, end the
		 * joined transaction and rejoin.
		 */
		if (btrfs_should_end_transaction(trans, send_root)) {
			ret = btrfs_end_transaction(trans, send_root);
			trans = NULL;
			if (ret < 0)
				goto out;
			btrfs_release_path(path);
			goto join_trans;
		}

		eb = path->nodes[0];
		slot = path->slots[0];
		btrfs_item_key_to_cpu(eb, &found_key, slot);

		ret = changed_cb(send_root, NULL, path, NULL,
				&found_key, BTRFS_COMPARE_TREE_NEW, sctx);
		if (ret < 0)
			goto out;

		key.objectid = found_key.objectid;
		key.type = found_key.type;
		key.offset = found_key.offset + 1;

		ret = btrfs_next_item(send_root, path);
		if (ret < 0)
			goto out;
		if (ret) {
			ret  = 0;
			break;
		}
	}

out_finish:
	ret = finish_inode_if_needed(sctx, 1);

out:
	btrfs_free_path(path);
	if (trans) {
		if (!ret)
			ret = btrfs_end_transaction(trans, send_root);
		else
			btrfs_end_transaction(trans, send_root);
	}
	return ret;
}

static int send_subvol(struct send_ctx *sctx)
{
	int ret;

	ret = send_header(sctx);
	if (ret < 0)
		goto out;

	ret = send_subvol_begin(sctx);
	if (ret < 0)
		goto out;

	if (sctx->parent_root) {
		ret = btrfs_compare_trees(sctx->send_root, sctx->parent_root,
				changed_cb, sctx);
		if (ret < 0)
			goto out;
		ret = finish_inode_if_needed(sctx, 1);
		if (ret < 0)
			goto out;
	} else {
		ret = full_send_tree(sctx);
		if (ret < 0)
			goto out;
	}

out:
	if (!ret)
		ret = close_cur_inode_file(sctx);
	else
		close_cur_inode_file(sctx);

	free_recorded_refs(sctx);
	return ret;
}

long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
{
	int ret = 0;
	struct btrfs_root *send_root;
	struct btrfs_root *clone_root;
	struct btrfs_fs_info *fs_info;
	struct btrfs_ioctl_send_args *arg = NULL;
	struct btrfs_key key;
	struct file *filp = NULL;
	struct send_ctx *sctx = NULL;
	u32 i;
	u64 *clone_sources_tmp = NULL;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	send_root = BTRFS_I(fdentry(mnt_file)->d_inode)->root;
	fs_info = send_root->fs_info;

	arg = memdup_user(arg_, sizeof(*arg));
	if (IS_ERR(arg)) {
		ret = PTR_ERR(arg);
		arg = NULL;
		goto out;
	}

	if (!access_ok(VERIFY_READ, arg->clone_sources,
			sizeof(*arg->clone_sources *
			arg->clone_sources_count))) {
		ret = -EFAULT;
		goto out;
	}

	sctx = kzalloc(sizeof(struct send_ctx), GFP_NOFS);
	if (!sctx) {
		ret = -ENOMEM;
		goto out;
	}

	INIT_LIST_HEAD(&sctx->new_refs);
	INIT_LIST_HEAD(&sctx->deleted_refs);
	INIT_RADIX_TREE(&sctx->name_cache, GFP_NOFS);
	INIT_LIST_HEAD(&sctx->name_cache_list);

	sctx->send_filp = fget(arg->send_fd);
	if (IS_ERR(sctx->send_filp)) {
		ret = PTR_ERR(sctx->send_filp);
		goto out;
	}

	sctx->mnt = mnt_file->f_path.mnt;

	sctx->send_root = send_root;
	sctx->clone_roots_cnt = arg->clone_sources_count;

	sctx->send_max_size = BTRFS_SEND_BUF_SIZE;
	sctx->send_buf = vmalloc(sctx->send_max_size);
	if (!sctx->send_buf) {
		ret = -ENOMEM;
		goto out;
	}

	sctx->read_buf = vmalloc(BTRFS_SEND_READ_SIZE);
	if (!sctx->read_buf) {
		ret = -ENOMEM;
		goto out;
	}

	sctx->clone_roots = vzalloc(sizeof(struct clone_root) *
			(arg->clone_sources_count + 1));
	if (!sctx->clone_roots) {
		ret = -ENOMEM;
		goto out;
	}

	if (arg->clone_sources_count) {
		clone_sources_tmp = vmalloc(arg->clone_sources_count *
				sizeof(*arg->clone_sources));
		if (!clone_sources_tmp) {
			ret = -ENOMEM;
			goto out;
		}

		ret = copy_from_user(clone_sources_tmp, arg->clone_sources,
				arg->clone_sources_count *
				sizeof(*arg->clone_sources));
		if (ret) {
			ret = -EFAULT;
			goto out;
		}

		for (i = 0; i < arg->clone_sources_count; i++) {
			key.objectid = clone_sources_tmp[i];
			key.type = BTRFS_ROOT_ITEM_KEY;
			key.offset = (u64)-1;
			clone_root = btrfs_read_fs_root_no_name(fs_info, &key);
			if (!clone_root) {
				ret = -EINVAL;
				goto out;
			}
			if (IS_ERR(clone_root)) {
				ret = PTR_ERR(clone_root);
				goto out;
			}
			sctx->clone_roots[i].root = clone_root;
		}
		vfree(clone_sources_tmp);
		clone_sources_tmp = NULL;
	}

	if (arg->parent_root) {
		key.objectid = arg->parent_root;
		key.type = BTRFS_ROOT_ITEM_KEY;
		key.offset = (u64)-1;
		sctx->parent_root = btrfs_read_fs_root_no_name(fs_info, &key);
		if (!sctx->parent_root) {
			ret = -EINVAL;
			goto out;
		}
	}

	/*
	 * Clones from send_root are allowed, but only if the clone source
	 * is behind the current send position. This is checked while searching
	 * for possible clone sources.
	 */
	sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root;

	/* We do a bsearch later */
	sort(sctx->clone_roots, sctx->clone_roots_cnt,
			sizeof(*sctx->clone_roots), __clone_root_cmp_sort,
			NULL);

	ret = send_subvol(sctx);
	if (ret < 0)
		goto out;

	ret = begin_cmd(sctx, BTRFS_SEND_C_END);
	if (ret < 0)
		goto out;
	ret = send_cmd(sctx);
	if (ret < 0)
		goto out;

out:
	if (filp)
		fput(filp);
	kfree(arg);
	vfree(clone_sources_tmp);

	if (sctx) {
		if (sctx->send_filp)
			fput(sctx->send_filp);

		vfree(sctx->clone_roots);
		vfree(sctx->send_buf);
		vfree(sctx->read_buf);

		name_cache_free(sctx);

		kfree(sctx);
	}

	return ret;
}