linux-stable/fs/btrfs/send.c
Dāvis Mosāns 2e7be9db12 btrfs: send: in case of IO error log it
Currently if we get IO error while doing send then we abort without
logging information about which file caused issue.  So log it to help
with debugging.

CC: stable@vger.kernel.org # 4.9+
Signed-off-by: Dāvis Mosāns <davispuh@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-02-09 18:53:26 +01:00

7778 lines
192 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2012 Alexander Block. All rights reserved.
*/
#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/vmalloc.h>
#include <linux/string.h>
#include <linux/compat.h>
#include <linux/crc32c.h>
#include "send.h"
#include "backref.h"
#include "locking.h"
#include "disk-io.h"
#include "btrfs_inode.h"
#include "transaction.h"
#include "compression.h"
#include "xattr.h"
#include "print-tree.h"
/*
* Maximum number of references an extent can have in order for us to attempt to
* issue clone operations instead of write operations. This currently exists to
* avoid hitting limitations of the backreference walking code (taking a lot of
* time and using too much memory for extents with large number of references).
*/
#define SEND_MAX_EXTENT_REFS 64
/*
* 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 *buf;
unsigned short buf_len:15;
unsigned short reversed:1;
char inline_buf[];
};
/*
* Average path length does not exceed 200 bytes, we'll have
* better packing in the slab and higher chance to satisfy
* a allocation later during send.
*/
char pad[256];
};
};
#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];
u64 flags; /* 'flags' member of btrfs_ioctl_send_args is u64 */
/* Protocol version compatibility requested */
u32 proto;
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;
/*
* Keep track of the generation of the last transaction that was used
* for relocating a block group. This is periodically checked in order
* to detect if a relocation happened since the last check, so that we
* don't operate on stale extent buffers for nodes (level >= 1) or on
* stale disk_bytenr values of file extent items.
*/
u64 last_reloc_trans;
/*
* 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 cur_inode_rdev;
u64 cur_inode_last_extent;
u64 cur_inode_next_write_offset;
bool ignore_cur_inode;
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_ra_state ra;
/*
* We process inodes by their increasing order, so if before an
* incremental send we reverse the parent/child relationship of
* directories such that a directory with a lower inode number was
* the parent of a directory with a higher inode number, and the one
* becoming the new parent got renamed too, we can't rename/move the
* directory with lower inode number when we finish processing it - we
* must process the directory with higher inode number first, then
* rename/move it and then rename/move the directory with lower inode
* number. Example follows.
*
* Tree state when the first send was performed:
*
* .
* |-- a (ino 257)
* |-- b (ino 258)
* |
* |
* |-- c (ino 259)
* | |-- d (ino 260)
* |
* |-- c2 (ino 261)
*
* Tree state when the second (incremental) send is performed:
*
* .
* |-- a (ino 257)
* |-- b (ino 258)
* |-- c2 (ino 261)
* |-- d2 (ino 260)
* |-- cc (ino 259)
*
* The sequence of steps that lead to the second state was:
*
* mv /a/b/c/d /a/b/c2/d2
* mv /a/b/c /a/b/c2/d2/cc
*
* "c" has lower inode number, but we can't move it (2nd mv operation)
* before we move "d", which has higher inode number.
*
* So we just memorize which move/rename operations must be performed
* later when their respective parent is processed and moved/renamed.
*/
/* Indexed by parent directory inode number. */
struct rb_root pending_dir_moves;
/*
* Reverse index, indexed by the inode number of a directory that
* is waiting for the move/rename of its immediate parent before its
* own move/rename can be performed.
*/
struct rb_root waiting_dir_moves;
/*
* A directory that is going to be rm'ed might have a child directory
* which is in the pending directory moves index above. In this case,
* the directory can only be removed after the move/rename of its child
* is performed. Example:
*
* Parent snapshot:
*
* . (ino 256)
* |-- a/ (ino 257)
* |-- b/ (ino 258)
* |-- c/ (ino 259)
* | |-- x/ (ino 260)
* |
* |-- y/ (ino 261)
*
* Send snapshot:
*
* . (ino 256)
* |-- a/ (ino 257)
* |-- b/ (ino 258)
* |-- YY/ (ino 261)
* |-- x/ (ino 260)
*
* Sequence of steps that lead to the send snapshot:
* rm -f /a/b/c/foo.txt
* mv /a/b/y /a/b/YY
* mv /a/b/c/x /a/b/YY
* rmdir /a/b/c
*
* When the child is processed, its move/rename is delayed until its
* parent is processed (as explained above), but all other operations
* like update utimes, chown, chgrp, etc, are performed and the paths
* that it uses for those operations must use the orphanized name of
* its parent (the directory we're going to rm later), so we need to
* memorize that name.
*
* Indexed by the inode number of the directory to be deleted.
*/
struct rb_root orphan_dirs;
};
struct pending_dir_move {
struct rb_node node;
struct list_head list;
u64 parent_ino;
u64 ino;
u64 gen;
struct list_head update_refs;
};
struct waiting_dir_move {
struct rb_node node;
u64 ino;
/*
* There might be some directory that could not be removed because it
* was waiting for this directory inode to be moved first. Therefore
* after this directory is moved, we can try to rmdir the ino rmdir_ino.
*/
u64 rmdir_ino;
u64 rmdir_gen;
bool orphanized;
};
struct orphan_dir_info {
struct rb_node node;
u64 ino;
u64 gen;
u64 last_dir_index_offset;
};
struct name_cache_entry {
struct list_head list;
/*
* 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;
u64 ino;
u64 gen;
u64 parent_ino;
u64 parent_gen;
int ret;
int need_later_update;
int name_len;
char name[];
};
#define ADVANCE 1
#define ADVANCE_ONLY_NEXT -1
enum btrfs_compare_tree_result {
BTRFS_COMPARE_TREE_NEW,
BTRFS_COMPARE_TREE_DELETED,
BTRFS_COMPARE_TREE_CHANGED,
BTRFS_COMPARE_TREE_SAME,
};
__cold
static void inconsistent_snapshot_error(struct send_ctx *sctx,
enum btrfs_compare_tree_result result,
const char *what)
{
const char *result_string;
switch (result) {
case BTRFS_COMPARE_TREE_NEW:
result_string = "new";
break;
case BTRFS_COMPARE_TREE_DELETED:
result_string = "deleted";
break;
case BTRFS_COMPARE_TREE_CHANGED:
result_string = "updated";
break;
case BTRFS_COMPARE_TREE_SAME:
ASSERT(0);
result_string = "unchanged";
break;
default:
ASSERT(0);
result_string = "unexpected";
}
btrfs_err(sctx->send_root->fs_info,
"Send: inconsistent snapshot, found %s %s for inode %llu without updated inode item, send root is %llu, parent root is %llu",
result_string, what, sctx->cmp_key->objectid,
sctx->send_root->root_key.objectid,
(sctx->parent_root ?
sctx->parent_root->root_key.objectid : 0));
}
__maybe_unused
static bool proto_cmd_ok(const struct send_ctx *sctx, int cmd)
{
switch (sctx->proto) {
case 1: return cmd < __BTRFS_SEND_C_MAX_V1;
case 2: return cmd < __BTRFS_SEND_C_MAX_V2;
default: return false;
}
}
static int is_waiting_for_move(struct send_ctx *sctx, u64 ino);
static struct waiting_dir_move *
get_waiting_dir_move(struct send_ctx *sctx, u64 ino);
static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen);
static int need_send_hole(struct send_ctx *sctx)
{
return (sctx->parent_root && !sctx->cur_inode_new &&
!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted &&
S_ISREG(sctx->cur_inode_mode));
}
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(void)
{
struct fs_path *p;
p = kmalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return NULL;
p->reversed = 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(void)
{
struct fs_path *p;
p = fs_path_alloc();
if (!p)
return NULL;
p->reversed = 1;
fs_path_reset(p);
return p;
}
static void fs_path_free(struct fs_path *p)
{
if (!p)
return;
if (p->buf != p->inline_buf)
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;
if (len > PATH_MAX) {
WARN_ON(1);
return -ENOMEM;
}
path_len = p->end - p->start;
old_buf_len = p->buf_len;
/*
* First time the inline_buf does not suffice
*/
if (p->buf == p->inline_buf) {
tmp_buf = kmalloc(len, GFP_KERNEL);
if (tmp_buf)
memcpy(tmp_buf, p->buf, old_buf_len);
} else {
tmp_buf = krealloc(p->buf, len, GFP_KERNEL);
}
if (!tmp_buf)
return -ENOMEM;
p->buf = tmp_buf;
/*
* The real size of the buffer is bigger, this will let the fast path
* happen most of the time
*/
p->buf_len = ksize(p->buf);
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,
char **prepared)
{
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;
*prepared = p->start;
} else {
if (p->start != p->end)
*p->end++ = '/';
*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;
char *prepared;
ret = fs_path_prepare_for_add(p, name_len, &prepared);
if (ret < 0)
goto out;
memcpy(prepared, name, name_len);
out:
return ret;
}
static int fs_path_add_path(struct fs_path *p, struct fs_path *p2)
{
int ret;
char *prepared;
ret = fs_path_prepare_for_add(p, p2->end - p2->start, &prepared);
if (ret < 0)
goto out;
memcpy(prepared, p2->start, p2->end - p2->start);
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;
char *prepared;
ret = fs_path_prepare_for_add(p, len, &prepared);
if (ret < 0)
goto out;
read_extent_buffer(eb, prepared, off, len);
out:
return ret;
}
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;
path->need_commit_sem = 1;
return path;
}
static int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off)
{
int ret;
u32 pos = 0;
while (pos < len) {
ret = kernel_write(filp, buf + pos, len - pos, off);
/* TODO handle that correctly */
/*if (ret == -ERESTARTSYS) {
continue;
}*/
if (ret < 0)
return ret;
if (ret == 0) {
return -EIO;
}
pos += ret;
}
return 0;
}
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);
put_unaligned_le16(attr, &hdr->tlv_type);
put_unaligned_le16(len, &hdr->tlv_len);
memcpy(hdr + 1, data, len);
sctx->send_size += total_len;
return 0;
}
#define TLV_PUT_DEFINE_INT(bits) \
static int tlv_put_u##bits(struct send_ctx *sctx, \
u##bits attr, u##bits value) \
{ \
__le##bits __tmp = cpu_to_le##bits(value); \
return tlv_put(sctx, attr, &__tmp, sizeof(__tmp)); \
}
TLV_PUT_DEFINE_INT(64)
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);
}
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, data, attrlen) \
do { \
ret = tlv_put(sctx, attrtype, data, attrlen); \
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_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->send_filp, &hdr, sizeof(hdr),
&sctx->send_off);
}
/*
* 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 (WARN_ON(!sctx->send_buf))
return -EINVAL;
BUG_ON(sctx->send_size);
sctx->send_size += sizeof(*hdr);
hdr = (struct btrfs_cmd_header *)sctx->send_buf;
put_unaligned_le16(cmd, &hdr->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;
put_unaligned_le32(sctx->send_size - sizeof(*hdr), &hdr->len);
put_unaligned_le32(0, &hdr->crc);
crc = btrfs_crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
put_unaligned_le32(crc, &hdr->crc);
ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size,
&sctx->send_off);
sctx->total_send_size += sctx->send_size;
sctx->cmd_send_size[get_unaligned_le16(&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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
btrfs_debug(fs_info, "send_rename %s -> %s", 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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
btrfs_debug(fs_info, "send_link %s -> %s", 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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
btrfs_debug(fs_info, "send_unlink %s", 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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
btrfs_debug(fs_info, "send_rmdir %s", 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, struct btrfs_path *path,
u64 ino, u64 *size, u64 *gen, u64 *mode, u64 *uid,
u64 *gid, u64 *rdev)
{
int ret;
struct btrfs_inode_item *ii;
struct btrfs_key key;
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret) {
if (ret > 0)
ret = -ENOENT;
return ret;
}
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);
if (rdev)
*rdev = btrfs_inode_rdev(path->nodes[0], ii);
return ret;
}
static int get_inode_info(struct btrfs_root *root,
u64 ino, u64 *size, u64 *gen,
u64 *mode, u64 *uid, u64 *gid,
u64 *rdev)
{
struct btrfs_path *path;
int ret;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
ret = __get_inode_info(root, path, ino, size, gen, mode, uid, gid,
rdev);
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 or
* btrfs_inode_extref.
* 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 or INODE_EXTREF when called.
*/
static int iterate_inode_ref(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 = path->nodes[0];
struct btrfs_inode_ref *iref;
struct btrfs_inode_extref *extref;
struct btrfs_path *tmp_path;
struct fs_path *p;
u32 cur = 0;
u32 total;
int slot = path->slots[0];
u32 name_len;
char *start;
int ret = 0;
int num = 0;
int index;
u64 dir;
unsigned long name_off;
unsigned long elem_size;
unsigned long ptr;
p = fs_path_alloc_reversed();
if (!p)
return -ENOMEM;
tmp_path = alloc_path_for_send();
if (!tmp_path) {
fs_path_free(p);
return -ENOMEM;
}
if (found_key->type == BTRFS_INODE_REF_KEY) {
ptr = (unsigned long)btrfs_item_ptr(eb, slot,
struct btrfs_inode_ref);
total = btrfs_item_size(eb, slot);
elem_size = sizeof(*iref);
} else {
ptr = btrfs_item_ptr_offset(eb, slot);
total = btrfs_item_size(eb, slot);
elem_size = sizeof(*extref);
}
while (cur < total) {
fs_path_reset(p);
if (found_key->type == BTRFS_INODE_REF_KEY) {
iref = (struct btrfs_inode_ref *)(ptr + cur);
name_len = btrfs_inode_ref_name_len(eb, iref);
name_off = (unsigned long)(iref + 1);
index = btrfs_inode_ref_index(eb, iref);
dir = found_key->offset;
} else {
extref = (struct btrfs_inode_extref *)(ptr + cur);
name_len = btrfs_inode_extref_name_len(eb, extref);
name_off = (unsigned long)&extref->name;
index = btrfs_inode_extref_index(eb, extref);
dir = btrfs_inode_extref_parent(eb, extref);
}
if (resolve) {
start = btrfs_ref_to_path(root, tmp_path, name_len,
name_off, eb, dir,
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_ref_to_path(root, tmp_path,
name_len, name_off,
eb, dir,
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, name_off,
name_len);
if (ret < 0)
goto out;
}
cur += elem_size + name_len;
ret = iterate(num, dir, index, p, ctx);
if (ret)
goto out;
num++;
}
out:
btrfs_free_path(tmp_path);
fs_path_free(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,
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 btrfs_root *root, struct btrfs_path *path,
iterate_dir_item_t iterate, void *ctx)
{
int ret = 0;
struct extent_buffer *eb;
struct btrfs_dir_item *di;
struct btrfs_key di_key;
char *buf = NULL;
int buf_len;
u32 name_len;
u32 data_len;
u32 cur;
u32 len;
u32 total;
int slot;
int num;
/*
* Start with a small buffer (1 page). If later we end up needing more
* space, which can happen for xattrs on a fs with a leaf size greater
* then the page size, attempt to increase the buffer. Typically xattr
* values are small.
*/
buf_len = PATH_MAX;
buf = kmalloc(buf_len, GFP_KERNEL);
if (!buf) {
ret = -ENOMEM;
goto out;
}
eb = path->nodes[0];
slot = path->slots[0];
di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
cur = 0;
len = 0;
total = btrfs_item_size(eb, slot);
num = 0;
while (cur < total) {
name_len = btrfs_dir_name_len(eb, di);
data_len = btrfs_dir_data_len(eb, di);
btrfs_dir_item_key_to_cpu(eb, di, &di_key);
if (btrfs_dir_type(eb, di) == BTRFS_FT_XATTR) {
if (name_len > XATTR_NAME_MAX) {
ret = -ENAMETOOLONG;
goto out;
}
if (name_len + data_len >
BTRFS_MAX_XATTR_SIZE(root->fs_info)) {
ret = -E2BIG;
goto out;
}
} else {
/*
* Path too long
*/
if (name_len + data_len > PATH_MAX) {
ret = -ENAMETOOLONG;
goto out;
}
}
if (name_len + data_len > buf_len) {
buf_len = name_len + data_len;
if (is_vmalloc_addr(buf)) {
vfree(buf);
buf = NULL;
} else {
char *tmp = krealloc(buf, buf_len,
GFP_KERNEL | __GFP_NOWARN);
if (!tmp)
kfree(buf);
buf = tmp;
}
if (!buf) {
buf = kvmalloc(buf_len, GFP_KERNEL);
if (!buf) {
ret = -ENOMEM;
goto out;
}
}
}
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, ctx);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
goto out;
}
num++;
}
out:
kvfree(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 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 &&
found_key.type != BTRFS_INODE_EXTREF_KEY)) {
ret = -ENOENT;
goto out;
}
ret = iterate_inode_ref(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 */
int found_itself;
};
static int __clone_root_cmp_bsearch(const void *key, const void *elt)
{
u64 root = (u64)(uintptr_t)key;
const struct clone_root *cr = elt;
if (root < cr->root->root_key.objectid)
return -1;
if (root > cr->root->root_key.objectid)
return 1;
return 0;
}
static int __clone_root_cmp_sort(const void *e1, const void *e2)
{
const struct clone_root *cr1 = e1;
const struct clone_root *cr2 = e2;
if (cr1->root->root_key.objectid < cr2->root->root_key.objectid)
return -1;
if (cr1->root->root_key.objectid > cr2->root->root_key.objectid)
return 1;
return 0;
}
/*
* Called for every backref that is found for the current extent.
* Results are collected in sctx->clone_roots->ino/offset/found_refs
*/
static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_)
{
struct backref_ctx *bctx = ctx_;
struct clone_root *found;
/* First check if the root is in the list of accepted clone sources */
found = bsearch((void *)(uintptr_t)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) {
bctx->found_itself = 1;
}
/*
* Make sure we don't consider clones from send_root that are
* behind the current inode/offset.
*/
if (found->root == bctx->sctx->send_root) {
/*
* If the source inode was not yet processed we can't issue a
* clone operation, as the source extent does not exist yet at
* the destination of the stream.
*/
if (ino > bctx->cur_objectid)
return 0;
/*
* We clone from the inode currently being sent as long as the
* source extent is already processed, otherwise we could try
* to clone from an extent that does not exist yet at the
* destination of the stream.
*/
if (ino == bctx->cur_objectid &&
offset + bctx->extent_len >
bctx->sctx->cur_inode_next_write_offset)
return 0;
}
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;
}
/*
* 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.
*
* 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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret;
int extent_type;
u64 logical;
u64 disk_byte;
u64 num_bytes;
u64 extent_item_pos;
u64 flags = 0;
struct btrfs_file_extent_item *fi;
struct extent_buffer *eb = path->nodes[0];
struct backref_ctx backref_ctx = {0};
struct clone_root *cur_clone_root;
struct btrfs_key found_key;
struct btrfs_path *tmp_path;
struct btrfs_extent_item *ei;
int compressed;
u32 i;
tmp_path = alloc_path_for_send();
if (!tmp_path)
return -ENOMEM;
/* We only use this path under the commit sem */
tmp_path->need_commit_sem = 0;
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;
}
compressed = btrfs_file_extent_compression(eb, fi);
num_bytes = btrfs_file_extent_num_bytes(eb, fi);
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
if (disk_byte == 0) {
ret = -ENOENT;
goto out;
}
logical = disk_byte + btrfs_file_extent_offset(eb, fi);
down_read(&fs_info->commit_root_sem);
ret = extent_from_logical(fs_info, disk_byte, tmp_path,
&found_key, &flags);
up_read(&fs_info->commit_root_sem);
if (ret < 0)
goto out;
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
ret = -EIO;
goto out;
}
ei = btrfs_item_ptr(tmp_path->nodes[0], tmp_path->slots[0],
struct btrfs_extent_item);
/*
* Backreference walking (iterate_extent_inodes() below) is currently
* too expensive when an extent has a large number of references, both
* in time spent and used memory. So for now just fallback to write
* operations instead of clone operations when an extent has more than
* a certain amount of references.
*/
if (btrfs_extent_refs(tmp_path->nodes[0], ei) > SEND_MAX_EXTENT_REFS) {
ret = -ENOENT;
goto out;
}
btrfs_release_path(tmp_path);
/*
* 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;
}
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;
/*
* 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)
backref_ctx.extent_len = ino_size - data_offset;
/*
* Now collect all backrefs.
*/
if (compressed == BTRFS_COMPRESS_NONE)
extent_item_pos = logical - found_key.objectid;
else
extent_item_pos = 0;
ret = iterate_extent_inodes(fs_info, found_key.objectid,
extent_item_pos, 1, __iterate_backrefs,
&backref_ctx, false);
if (ret < 0)
goto out;
down_read(&fs_info->commit_root_sem);
if (fs_info->last_reloc_trans > sctx->last_reloc_trans) {
/*
* A transaction commit for a transaction in which block group
* relocation was done just happened.
* The disk_bytenr of the file extent item we processed is
* possibly stale, referring to the extent's location before
* relocation. So act as if we haven't found any clone sources
* and fallback to write commands, which will read the correct
* data from the new extent location. Otherwise we will fail
* below because we haven't found our own back reference or we
* could be getting incorrect sources in case the old extent
* was already reallocated after the relocation.
*/
up_read(&fs_info->commit_root_sem);
ret = -ENOENT;
goto out;
}
up_read(&fs_info->commit_root_sem);
if (!backref_ctx.found_itself) {
/* found a bug in backref code? */
ret = -EIO;
btrfs_err(fs_info,
"did not find backref in send_root. inode=%llu, offset=%llu, disk_byte=%llu found extent=%llu",
ino, data_offset, disk_byte, found_key.objectid);
goto out;
}
btrfs_debug(fs_info,
"find_extent_clone: data_offset=%llu, ino=%llu, num_bytes=%llu, logical=%llu",
data_offset, ino, num_bytes, logical);
if (!backref_ctx.found)
btrfs_debug(fs_info, "no clones found");
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);
return ret;
}
static int read_symlink(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;
if (ret) {
/*
* An empty symlink inode. Can happen in rare error paths when
* creating a symlink (transaction committed before the inode
* eviction handler removed the symlink inode items and a crash
* happened in between or the subvol was snapshoted in between).
* Print an informative message to dmesg/syslog so that the user
* can delete the symlink.
*/
btrfs_err(root->fs_info,
"Found empty symlink inode %llu at root %llu",
ino, root->root_key.objectid);
ret = -EIO;
goto out;
}
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_ram_bytes(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), "o%llu-%llu-%llu",
ino, gen, idx);
ASSERT(len < sizeof(tmp));
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,
NULL, NULL);
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,
NULL, NULL, NULL, NULL);
if (ret < 0 && ret != -ENOENT)
goto out;
right_ret = ret;
}
if (!left_ret && !right_ret) {
if (left_gen == gen && right_gen == gen) {
ret = inode_state_no_change;
} else if (left_gen == gen) {
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;
if (ino == BTRFS_FIRST_FREE_OBJECTID)
return 1;
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)
{
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 (IS_ERR_OR_NULL(di)) {
ret = di ? PTR_ERR(di) : -ENOENT;
goto out;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
if (key.type == BTRFS_ROOT_ITEM_KEY) {
ret = -ENOENT;
goto out;
}
*found_inode = key.objectid;
out:
btrfs_free_path(path);
return ret;
}
/*
* 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.
*/
static int get_first_ref(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;
int len;
u64 parent_dir;
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 != ino ||
(found_key.type != BTRFS_INODE_REF_KEY &&
found_key.type != BTRFS_INODE_EXTREF_KEY)) {
ret = -ENOENT;
goto out;
}
if (found_key.type == BTRFS_INODE_REF_KEY) {
struct btrfs_inode_ref *iref;
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);
parent_dir = found_key.offset;
} else {
struct btrfs_inode_extref *extref;
extref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_extref);
len = btrfs_inode_extref_name_len(path->nodes[0], extref);
ret = fs_path_add_from_extent_buffer(name, path->nodes[0],
(unsigned long)&extref->name, len);
parent_dir = btrfs_inode_extref_parent(path->nodes[0], extref);
}
if (ret < 0)
goto out;
btrfs_release_path(path);
if (dir_gen) {
ret = get_inode_info(root, parent_dir, NULL, dir_gen, NULL,
NULL, NULL, NULL);
if (ret < 0)
goto out;
}
*dir = parent_dir;
out:
btrfs_free_path(path);
return ret;
}
static int is_first_ref(struct btrfs_root *root,
u64 ino, u64 dir,
const char *name, int name_len)
{
int ret;
struct fs_path *tmp_name;
u64 tmp_dir;
tmp_name = fs_path_alloc();
if (!tmp_name)
return -ENOMEM;
ret = get_first_ref(root, ino, &tmp_dir, NULL, tmp_name);
if (ret < 0)
goto out;
if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) {
ret = 0;
goto out;
}
ret = !memcmp(tmp_name->start, name, name_len);
out:
fs_path_free(tmp_name);
return ret;
}
/*
* 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.
*/
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, u64 *who_mode)
{
int ret = 0;
u64 gen;
u64 other_inode = 0;
if (!sctx->parent_root)
goto out;
ret = is_inode_existent(sctx, dir, dir_gen);
if (ret <= 0)
goto out;
/*
* If we have a parent root we need to verify that the parent dir was
* not deleted and then re-created, if it was then we have no overwrite
* and we can just unlink this entry.
*/
if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID) {
ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL,
NULL, NULL, NULL);
if (ret < 0 && ret != -ENOENT)
goto out;
if (ret) {
ret = 0;
goto out;
}
if (gen != dir_gen)
goto out;
}
ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
&other_inode);
if (ret < 0 && ret != -ENOENT)
goto out;
if (ret) {
ret = 0;
goto out;
}
/*
* 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.
*/
if (other_inode > sctx->send_progress ||
is_waiting_for_move(sctx, other_inode)) {
ret = get_inode_info(sctx->parent_root, other_inode, NULL,
who_gen, who_mode, NULL, NULL, NULL);
if (ret < 0)
goto out;
ret = 1;
*who_ino = other_inode;
} else {
ret = 0;
}
out:
return ret;
}
/*
* 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.
*/
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;
if (!sctx->parent_root)
goto out;
ret = is_inode_existent(sctx, dir, dir_gen);
if (ret <= 0)
goto out;
if (dir != BTRFS_FIRST_FREE_OBJECTID) {
ret = get_inode_info(sctx->send_root, dir, NULL, &gen, NULL,
NULL, NULL, NULL);
if (ret < 0 && ret != -ENOENT)
goto out;
if (ret) {
ret = 0;
goto out;
}
if (gen != dir_gen)
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);
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,
NULL, NULL);
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.
* The current inode being processed might have been the one that caused
* inode 'ino' to be orphanized, therefore check if ow_inode matches
* the current inode being processed.
*/
if ((ow_inode < sctx->send_progress) ||
(ino != sctx->cur_ino && ow_inode == sctx->cur_ino &&
gen == sctx->cur_inode_gen))
ret = 1;
else
ret = 0;
out:
return ret;
}
/*
* 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.
*/
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();
if (!name)
return -ENOMEM;
ret = get_first_ref(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(name);
return ret;
}
/*
* 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.
* In case of error, nce is kfreed.
*/
static int name_cache_insert(struct send_ctx *sctx,
struct name_cache_entry *nce)
{
int ret = 0;
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_KERNEL);
if (!nce_head) {
kfree(nce);
return -ENOMEM;
}
INIT_LIST_HEAD(nce_head);
ret = radix_tree_insert(&sctx->name_cache, nce->ino, nce_head);
if (ret < 0) {
kfree(nce_head);
kfree(nce);
return ret;
}
}
list_add_tail(&nce->radix_list, nce_head);
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)
{
struct list_head *nce_head;
nce_head = radix_tree_lookup(&sctx->name_cache,
(unsigned long)nce->ino);
if (!nce_head) {
btrfs_err(sctx->send_root->fs_info,
"name_cache_delete lookup failed ino %llu cache size %d, leaking memory",
nce->ino, sctx->name_cache_size);
}
list_del(&nce->radix_list);
list_del(&nce->list);
sctx->name_cache_size--;
/*
* We may not get to the final release of nce_head if the lookup fails
*/
if (nce_head && list_empty(nce_head)) {
radix_tree_delete(&sctx->name_cache, (unsigned long)nce->ino);
kfree(nce_head);
}
}
static struct name_cache_entry *name_cache_search(struct send_ctx *sctx,
u64 ino, u64 gen)
{
struct list_head *nce_head;
struct name_cache_entry *cur;
nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)ino);
if (!nce_head)
return NULL;
list_for_each_entry(cur, nce_head, radix_list) {
if (cur->ino == ino && cur->gen == gen)
return cur;
}
return NULL;
}
/*
* Remove some entries from the beginning of name_cache_list.
*/
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;
while (!list_empty(&sctx->name_cache_list)) {
nce = list_entry(sctx->name_cache_list.next,
struct name_cache_entry, list);
name_cache_delete(sctx, nce);
kfree(nce);
}
}
/*
* 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.
*/
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 name_cache_entry *nce = NULL;
/*
* 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.
*/
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 {
/*
* 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.
*/
list_move_tail(&nce->list, &sctx->name_cache_list);
*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;
}
}
/*
* 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
*/
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;
}
/*
* Depending on whether the inode was already processed or not, use
* send_root or parent_root for ref lookup.
*/
if (ino < sctx->send_progress)
ret = get_first_ref(sctx->send_root, ino,
parent_ino, parent_gen, dest);
else
ret = get_first_ref(sctx->parent_root, ino,
parent_ino, parent_gen, dest);
if (ret < 0)
goto out;
/*
* Check if the ref was overwritten by an inode's ref that was processed
* earlier. If yes, treat as orphan and return 1.
*/
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:
/*
* Store the result of the lookup in the name cache.
*/
nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_KERNEL);
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:
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 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();
if (!name) {
ret = -ENOMEM;
goto out;
}
dest->reversed = 1;
fs_path_reset(dest);
while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) {
struct waiting_dir_move *wdm;
fs_path_reset(name);
if (is_waiting_for_rm(sctx, ino, gen)) {
ret = gen_unique_name(sctx, ino, gen, name);
if (ret < 0)
goto out;
ret = fs_path_add_path(dest, name);
break;
}
wdm = get_waiting_dir_move(sctx, ino);
if (wdm && wdm->orphanized) {
ret = gen_unique_name(sctx, ino, gen, name);
stop = 1;
} else if (wdm) {
ret = get_first_ref(sctx->parent_root, ino,
&parent_inode, &parent_gen, name);
} else {
ret = __get_cur_name_and_parent(sctx, ino, gen,
&parent_inode,
&parent_gen, name);
if (ret)
stop = 1;
}
if (ret < 0)
goto out;
ret = fs_path_add_path(dest, name);
if (ret < 0)
goto out;
ino = parent_inode;
gen = parent_gen;
}
out:
fs_path_free(name);
if (!ret)
fs_path_unreverse(dest);
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 = btrfs_alloc_path();
if (!path)
return -ENOMEM;
name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL);
if (!name) {
btrfs_free_path(path);
return -ENOMEM;
}
key.objectid = send_root->root_key.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->root_key.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);
if (!btrfs_is_empty_uuid(sctx->send_root->root_item.received_uuid))
TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
sctx->send_root->root_item.received_uuid);
else
TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID,
sctx->send_root->root_item.uuid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID,
btrfs_root_ctransid(&sctx->send_root->root_item));
if (parent_root) {
if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid))
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
parent_root->root_item.received_uuid);
else
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
parent_root->root_item.uuid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
btrfs_root_ctransid(&sctx->parent_root->root_item));
}
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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
btrfs_debug(fs_info, "send_truncate %llu size=%llu", ino, size);
p = fs_path_alloc();
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(p);
return ret;
}
static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
btrfs_debug(fs_info, "send_chmod %llu mode=%llu", ino, mode);
p = fs_path_alloc();
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(p);
return ret;
}
static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
btrfs_debug(fs_info, "send_chown %llu uid=%llu, gid=%llu",
ino, uid, gid);
p = fs_path_alloc();
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(p);
return ret;
}
static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
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;
btrfs_debug(fs_info, "send_utimes %llu", ino);
p = fs_path_alloc();
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)
ret = -ENOENT;
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, &ii->atime);
TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb, &ii->mtime);
TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb, &ii->ctime);
/* TODO Add otime support when the otime patches get into upstream */
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(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.
*/
static int send_create_inode(struct send_ctx *sctx, u64 ino)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
int cmd;
u64 gen;
u64 mode;
u64 rdev;
btrfs_debug(fs_info, "send_create_inode %llu", ino);
p = fs_path_alloc();
if (!p)
return -ENOMEM;
if (ino != sctx->cur_ino) {
ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode,
NULL, NULL, &rdev);
if (ret < 0)
goto out;
} else {
gen = sctx->cur_inode_gen;
mode = sctx->cur_inode_mode;
rdev = sctx->cur_inode_rdev;
}
if (S_ISREG(mode)) {
cmd = BTRFS_SEND_C_MKFILE;
} else if (S_ISDIR(mode)) {
cmd = BTRFS_SEND_C_MKDIR;
} else if (S_ISLNK(mode)) {
cmd = BTRFS_SEND_C_SYMLINK;
} else if (S_ISCHR(mode) || S_ISBLK(mode)) {
cmd = BTRFS_SEND_C_MKNOD;
} else if (S_ISFIFO(mode)) {
cmd = BTRFS_SEND_C_MKFIFO;
} else if (S_ISSOCK(mode)) {
cmd = BTRFS_SEND_C_MKSOCK;
} else {
btrfs_warn(sctx->send_root->fs_info, "unexpected inode type %o",
(int)(mode & S_IFMT));
ret = -EOPNOTSUPP;
goto out;
}
ret = begin_cmd(sctx, cmd);
if (ret < 0)
goto out;
ret = gen_unique_name(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_INO, ino);
if (S_ISLNK(mode)) {
fs_path_reset(p);
ret = read_symlink(sctx->send_root, ino, p);
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)) {
TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, new_encode_dev(rdev));
TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode);
}
ret = send_cmd(sctx);
if (ret < 0)
goto out;
tlv_put_failure:
out:
fs_path_free(p);
return ret;
}
/*
* 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;
ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(sctx->send_root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
break;
}
continue;
}
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (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.type != BTRFS_ROOT_ITEM_KEY &&
di_key.objectid < sctx->send_progress) {
ret = 1;
goto out;
}
path->slots[0]++;
}
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)
return ret;
else if (ret > 0)
return 0;
}
return send_create_inode(sctx, sctx->cur_ino);
}
struct recorded_ref {
struct list_head list;
char *name;
struct fs_path *full_path;
u64 dir;
u64 dir_gen;
int name_len;
};
static void set_ref_path(struct recorded_ref *ref, struct fs_path *path)
{
ref->full_path = path;
ref->name = (char *)kbasename(ref->full_path->start);
ref->name_len = ref->full_path->end - ref->name;
}
/*
* 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;
ref = kmalloc(sizeof(*ref), GFP_KERNEL);
if (!ref)
return -ENOMEM;
ref->dir = dir;
ref->dir_gen = dir_gen;
set_ref_path(ref, path);
list_add_tail(&ref->list, head);
return 0;
}
static int dup_ref(struct recorded_ref *ref, struct list_head *list)
{
struct recorded_ref *new;
new = kmalloc(sizeof(*ref), GFP_KERNEL);
if (!new)
return -ENOMEM;
new->dir = ref->dir;
new->dir_gen = ref->dir_gen;
new->full_path = NULL;
INIT_LIST_HEAD(&new->list);
list_add_tail(&new->list, list);
return 0;
}
static void __free_recorded_refs(struct list_head *head)
{
struct recorded_ref *cur;
while (!list_empty(head)) {
cur = list_entry(head->next, struct recorded_ref, list);
fs_path_free(cur->full_path);
list_del(&cur->list);
kfree(cur);
}
}
static void free_recorded_refs(struct send_ctx *sctx)
{
__free_recorded_refs(&sctx->new_refs);
__free_recorded_refs(&sctx->deleted_refs);
}
/*
* Renames/moves a file/dir to its orphan name. Used when the first
* 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();
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(orphan);
return ret;
}
static struct orphan_dir_info *add_orphan_dir_info(struct send_ctx *sctx,
u64 dir_ino, u64 dir_gen)
{
struct rb_node **p = &sctx->orphan_dirs.rb_node;
struct rb_node *parent = NULL;
struct orphan_dir_info *entry, *odi;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct orphan_dir_info, node);
if (dir_ino < entry->ino)
p = &(*p)->rb_left;
else if (dir_ino > entry->ino)
p = &(*p)->rb_right;
else if (dir_gen < entry->gen)
p = &(*p)->rb_left;
else if (dir_gen > entry->gen)
p = &(*p)->rb_right;
else
return entry;
}
odi = kmalloc(sizeof(*odi), GFP_KERNEL);
if (!odi)
return ERR_PTR(-ENOMEM);
odi->ino = dir_ino;
odi->gen = dir_gen;
odi->last_dir_index_offset = 0;
rb_link_node(&odi->node, parent, p);
rb_insert_color(&odi->node, &sctx->orphan_dirs);
return odi;
}
static struct orphan_dir_info *get_orphan_dir_info(struct send_ctx *sctx,
u64 dir_ino, u64 gen)
{
struct rb_node *n = sctx->orphan_dirs.rb_node;
struct orphan_dir_info *entry;
while (n) {
entry = rb_entry(n, struct orphan_dir_info, node);
if (dir_ino < entry->ino)
n = n->rb_left;
else if (dir_ino > entry->ino)
n = n->rb_right;
else if (gen < entry->gen)
n = n->rb_left;
else if (gen > entry->gen)
n = n->rb_right;
else
return entry;
}
return NULL;
}
static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen)
{
struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino, gen);
return odi != NULL;
}
static void free_orphan_dir_info(struct send_ctx *sctx,
struct orphan_dir_info *odi)
{
if (!odi)
return;
rb_erase(&odi->node, &sctx->orphan_dirs);
kfree(odi);
}
/*
* 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 dir_gen,
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;
struct orphan_dir_info *odi = NULL;
/*
* Don't try to rmdir the top/root subvolume dir.
*/
if (dir == BTRFS_FIRST_FREE_OBJECTID)
return 0;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = dir;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
odi = get_orphan_dir_info(sctx, dir, dir_gen);
if (odi)
key.offset = odi->last_dir_index_offset;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
struct waiting_dir_move *dm;
if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
if (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);
dm = get_waiting_dir_move(sctx, loc.objectid);
if (dm) {
odi = add_orphan_dir_info(sctx, dir, dir_gen);
if (IS_ERR(odi)) {
ret = PTR_ERR(odi);
goto out;
}
odi->gen = dir_gen;
odi->last_dir_index_offset = found_key.offset;
dm->rmdir_ino = dir;
dm->rmdir_gen = dir_gen;
ret = 0;
goto out;
}
if (loc.objectid > send_progress) {
odi = add_orphan_dir_info(sctx, dir, dir_gen);
if (IS_ERR(odi)) {
ret = PTR_ERR(odi);
goto out;
}
odi->gen = dir_gen;
odi->last_dir_index_offset = found_key.offset;
ret = 0;
goto out;
}
path->slots[0]++;
}
free_orphan_dir_info(sctx, odi);
ret = 1;
out:
btrfs_free_path(path);
return ret;
}
static int is_waiting_for_move(struct send_ctx *sctx, u64 ino)
{
struct waiting_dir_move *entry = get_waiting_dir_move(sctx, ino);
return entry != NULL;
}
static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino, bool orphanized)
{
struct rb_node **p = &sctx->waiting_dir_moves.rb_node;
struct rb_node *parent = NULL;
struct waiting_dir_move *entry, *dm;
dm = kmalloc(sizeof(*dm), GFP_KERNEL);
if (!dm)
return -ENOMEM;
dm->ino = ino;
dm->rmdir_ino = 0;
dm->rmdir_gen = 0;
dm->orphanized = orphanized;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct waiting_dir_move, node);
if (ino < entry->ino) {
p = &(*p)->rb_left;
} else if (ino > entry->ino) {
p = &(*p)->rb_right;
} else {
kfree(dm);
return -EEXIST;
}
}
rb_link_node(&dm->node, parent, p);
rb_insert_color(&dm->node, &sctx->waiting_dir_moves);
return 0;
}
static struct waiting_dir_move *
get_waiting_dir_move(struct send_ctx *sctx, u64 ino)
{
struct rb_node *n = sctx->waiting_dir_moves.rb_node;
struct waiting_dir_move *entry;
while (n) {
entry = rb_entry(n, struct waiting_dir_move, node);
if (ino < entry->ino)
n = n->rb_left;
else if (ino > entry->ino)
n = n->rb_right;
else
return entry;
}
return NULL;
}
static void free_waiting_dir_move(struct send_ctx *sctx,
struct waiting_dir_move *dm)
{
if (!dm)
return;
rb_erase(&dm->node, &sctx->waiting_dir_moves);
kfree(dm);
}
static int add_pending_dir_move(struct send_ctx *sctx,
u64 ino,
u64 ino_gen,
u64 parent_ino,
struct list_head *new_refs,
struct list_head *deleted_refs,
const bool is_orphan)
{
struct rb_node **p = &sctx->pending_dir_moves.rb_node;
struct rb_node *parent = NULL;
struct pending_dir_move *entry = NULL, *pm;
struct recorded_ref *cur;
int exists = 0;
int ret;
pm = kmalloc(sizeof(*pm), GFP_KERNEL);
if (!pm)
return -ENOMEM;
pm->parent_ino = parent_ino;
pm->ino = ino;
pm->gen = ino_gen;
INIT_LIST_HEAD(&pm->list);
INIT_LIST_HEAD(&pm->update_refs);
RB_CLEAR_NODE(&pm->node);
while (*p) {
parent = *p;
entry = rb_entry(parent, struct pending_dir_move, node);
if (parent_ino < entry->parent_ino) {
p = &(*p)->rb_left;
} else if (parent_ino > entry->parent_ino) {
p = &(*p)->rb_right;
} else {
exists = 1;
break;
}
}
list_for_each_entry(cur, deleted_refs, list) {
ret = dup_ref(cur, &pm->update_refs);
if (ret < 0)
goto out;
}
list_for_each_entry(cur, new_refs, list) {
ret = dup_ref(cur, &pm->update_refs);
if (ret < 0)
goto out;
}
ret = add_waiting_dir_move(sctx, pm->ino, is_orphan);
if (ret)
goto out;
if (exists) {
list_add_tail(&pm->list, &entry->list);
} else {
rb_link_node(&pm->node, parent, p);
rb_insert_color(&pm->node, &sctx->pending_dir_moves);
}
ret = 0;
out:
if (ret) {
__free_recorded_refs(&pm->update_refs);
kfree(pm);
}
return ret;
}
static struct pending_dir_move *get_pending_dir_moves(struct send_ctx *sctx,
u64 parent_ino)
{
struct rb_node *n = sctx->pending_dir_moves.rb_node;
struct pending_dir_move *entry;
while (n) {
entry = rb_entry(n, struct pending_dir_move, node);
if (parent_ino < entry->parent_ino)
n = n->rb_left;
else if (parent_ino > entry->parent_ino)
n = n->rb_right;
else
return entry;
}
return NULL;
}
static int path_loop(struct send_ctx *sctx, struct fs_path *name,
u64 ino, u64 gen, u64 *ancestor_ino)
{
int ret = 0;
u64 parent_inode = 0;
u64 parent_gen = 0;
u64 start_ino = ino;
*ancestor_ino = 0;
while (ino != BTRFS_FIRST_FREE_OBJECTID) {
fs_path_reset(name);
if (is_waiting_for_rm(sctx, ino, gen))
break;
if (is_waiting_for_move(sctx, ino)) {
if (*ancestor_ino == 0)
*ancestor_ino = ino;
ret = get_first_ref(sctx->parent_root, ino,
&parent_inode, &parent_gen, name);
} else {
ret = __get_cur_name_and_parent(sctx, ino, gen,
&parent_inode,
&parent_gen, name);
if (ret > 0) {
ret = 0;
break;
}
}
if (ret < 0)
break;
if (parent_inode == start_ino) {
ret = 1;
if (*ancestor_ino == 0)
*ancestor_ino = ino;
break;
}
ino = parent_inode;
gen = parent_gen;
}
return ret;
}
static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm)
{
struct fs_path *from_path = NULL;
struct fs_path *to_path = NULL;
struct fs_path *name = NULL;
u64 orig_progress = sctx->send_progress;
struct recorded_ref *cur;
u64 parent_ino, parent_gen;
struct waiting_dir_move *dm = NULL;
u64 rmdir_ino = 0;
u64 rmdir_gen;
u64 ancestor;
bool is_orphan;
int ret;
name = fs_path_alloc();
from_path = fs_path_alloc();
if (!name || !from_path) {
ret = -ENOMEM;
goto out;
}
dm = get_waiting_dir_move(sctx, pm->ino);
ASSERT(dm);
rmdir_ino = dm->rmdir_ino;
rmdir_gen = dm->rmdir_gen;
is_orphan = dm->orphanized;
free_waiting_dir_move(sctx, dm);
if (is_orphan) {
ret = gen_unique_name(sctx, pm->ino,
pm->gen, from_path);
} else {
ret = get_first_ref(sctx->parent_root, pm->ino,
&parent_ino, &parent_gen, name);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, parent_ino, parent_gen,
from_path);
if (ret < 0)
goto out;
ret = fs_path_add_path(from_path, name);
}
if (ret < 0)
goto out;
sctx->send_progress = sctx->cur_ino + 1;
ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor);
if (ret < 0)
goto out;
if (ret) {
LIST_HEAD(deleted_refs);
ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID);
ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor,
&pm->update_refs, &deleted_refs,
is_orphan);
if (ret < 0)
goto out;
if (rmdir_ino) {
dm = get_waiting_dir_move(sctx, pm->ino);
ASSERT(dm);
dm->rmdir_ino = rmdir_ino;
dm->rmdir_gen = rmdir_gen;
}
goto out;
}
fs_path_reset(name);
to_path = name;
name = NULL;
ret = get_cur_path(sctx, pm->ino, pm->gen, to_path);
if (ret < 0)
goto out;
ret = send_rename(sctx, from_path, to_path);
if (ret < 0)
goto out;
if (rmdir_ino) {
struct orphan_dir_info *odi;
u64 gen;
odi = get_orphan_dir_info(sctx, rmdir_ino, rmdir_gen);
if (!odi) {
/* already deleted */
goto finish;
}
gen = odi->gen;
ret = can_rmdir(sctx, rmdir_ino, gen, sctx->cur_ino);
if (ret < 0)
goto out;
if (!ret)
goto finish;
name = fs_path_alloc();
if (!name) {
ret = -ENOMEM;
goto out;
}
ret = get_cur_path(sctx, rmdir_ino, gen, name);
if (ret < 0)
goto out;
ret = send_rmdir(sctx, name);
if (ret < 0)
goto out;
}
finish:
ret = send_utimes(sctx, pm->ino, pm->gen);
if (ret < 0)
goto out;
/*
* After rename/move, need to update the utimes of both new parent(s)
* and old parent(s).
*/
list_for_each_entry(cur, &pm->update_refs, list) {
/*
* The parent inode might have been deleted in the send snapshot
*/
ret = get_inode_info(sctx->send_root, cur->dir, NULL,
NULL, NULL, NULL, NULL, NULL);
if (ret == -ENOENT) {
ret = 0;
continue;
}
if (ret < 0)
goto out;
ret = send_utimes(sctx, cur->dir, cur->dir_gen);
if (ret < 0)
goto out;
}
out:
fs_path_free(name);
fs_path_free(from_path);
fs_path_free(to_path);
sctx->send_progress = orig_progress;
return ret;
}
static void free_pending_move(struct send_ctx *sctx, struct pending_dir_move *m)
{
if (!list_empty(&m->list))
list_del(&m->list);
if (!RB_EMPTY_NODE(&m->node))
rb_erase(&m->node, &sctx->pending_dir_moves);
__free_recorded_refs(&m->update_refs);
kfree(m);
}
static void tail_append_pending_moves(struct send_ctx *sctx,
struct pending_dir_move *moves,
struct list_head *stack)
{
if (list_empty(&moves->list)) {
list_add_tail(&moves->list, stack);
} else {
LIST_HEAD(list);
list_splice_init(&moves->list, &list);
list_add_tail(&moves->list, stack);
list_splice_tail(&list, stack);
}
if (!RB_EMPTY_NODE(&moves->node)) {
rb_erase(&moves->node, &sctx->pending_dir_moves);
RB_CLEAR_NODE(&moves->node);
}
}
static int apply_children_dir_moves(struct send_ctx *sctx)
{
struct pending_dir_move *pm;
struct list_head stack;
u64 parent_ino = sctx->cur_ino;
int ret = 0;
pm = get_pending_dir_moves(sctx, parent_ino);
if (!pm)
return 0;
INIT_LIST_HEAD(&stack);
tail_append_pending_moves(sctx, pm, &stack);
while (!list_empty(&stack)) {
pm = list_first_entry(&stack, struct pending_dir_move, list);
parent_ino = pm->ino;
ret = apply_dir_move(sctx, pm);
free_pending_move(sctx, pm);
if (ret)
goto out;
pm = get_pending_dir_moves(sctx, parent_ino);
if (pm)
tail_append_pending_moves(sctx, pm, &stack);
}
return 0;
out:
while (!list_empty(&stack)) {
pm = list_first_entry(&stack, struct pending_dir_move, list);
free_pending_move(sctx, pm);
}
return ret;
}
/*
* We might need to delay a directory rename even when no ancestor directory
* (in the send root) with a higher inode number than ours (sctx->cur_ino) was
* renamed. This happens when we rename a directory to the old name (the name
* in the parent root) of some other unrelated directory that got its rename
* delayed due to some ancestor with higher number that got renamed.
*
* Example:
*
* Parent snapshot:
* . (ino 256)
* |---- a/ (ino 257)
* | |---- file (ino 260)
* |
* |---- b/ (ino 258)
* |---- c/ (ino 259)
*
* Send snapshot:
* . (ino 256)
* |---- a/ (ino 258)
* |---- x/ (ino 259)
* |---- y/ (ino 257)
* |----- file (ino 260)
*
* Here we can not rename 258 from 'b' to 'a' without the rename of inode 257
* from 'a' to 'x/y' happening first, which in turn depends on the rename of
* inode 259 from 'c' to 'x'. So the order of rename commands the send stream
* must issue is:
*
* 1 - rename 259 from 'c' to 'x'
* 2 - rename 257 from 'a' to 'x/y'
* 3 - rename 258 from 'b' to 'a'
*
* Returns 1 if the rename of sctx->cur_ino needs to be delayed, 0 if it can
* be done right away and < 0 on error.
*/
static int wait_for_dest_dir_move(struct send_ctx *sctx,
struct recorded_ref *parent_ref,
const bool is_orphan)
{
struct btrfs_fs_info *fs_info = sctx->parent_root->fs_info;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key di_key;
struct btrfs_dir_item *di;
u64 left_gen;
u64 right_gen;
int ret = 0;
struct waiting_dir_move *wdm;
if (RB_EMPTY_ROOT(&sctx->waiting_dir_moves))
return 0;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = parent_ref->dir;
key.type = BTRFS_DIR_ITEM_KEY;
key.offset = btrfs_name_hash(parent_ref->name, parent_ref->name_len);
ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
goto out;
}
di = btrfs_match_dir_item_name(fs_info, path, parent_ref->name,
parent_ref->name_len);
if (!di) {
ret = 0;
goto out;
}
/*
* di_key.objectid has the number of the inode that has a dentry in the
* parent directory with the same name that sctx->cur_ino is being
* renamed to. We need to check if that inode is in the send root as
* well and if it is currently marked as an inode with a pending rename,
* if it is, we need to delay the rename of sctx->cur_ino as well, so
* that it happens after that other inode is renamed.
*/
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &di_key);
if (di_key.type != BTRFS_INODE_ITEM_KEY) {
ret = 0;
goto out;
}
ret = get_inode_info(sctx->parent_root, di_key.objectid, NULL,
&left_gen, NULL, NULL, NULL, NULL);
if (ret < 0)
goto out;
ret = get_inode_info(sctx->send_root, di_key.objectid, NULL,
&right_gen, NULL, NULL, NULL, NULL);
if (ret < 0) {
if (ret == -ENOENT)
ret = 0;
goto out;
}
/* Different inode, no need to delay the rename of sctx->cur_ino */
if (right_gen != left_gen) {
ret = 0;
goto out;
}
wdm = get_waiting_dir_move(sctx, di_key.objectid);
if (wdm && !wdm->orphanized) {
ret = add_pending_dir_move(sctx,
sctx->cur_ino,
sctx->cur_inode_gen,
di_key.objectid,
&sctx->new_refs,
&sctx->deleted_refs,
is_orphan);
if (!ret)
ret = 1;
}
out:
btrfs_free_path(path);
return ret;
}
/*
* Check if inode ino2, or any of its ancestors, is inode ino1.
* Return 1 if true, 0 if false and < 0 on error.
*/
static int check_ino_in_path(struct btrfs_root *root,
const u64 ino1,
const u64 ino1_gen,
const u64 ino2,
const u64 ino2_gen,
struct fs_path *fs_path)
{
u64 ino = ino2;
if (ino1 == ino2)
return ino1_gen == ino2_gen;
while (ino > BTRFS_FIRST_FREE_OBJECTID) {
u64 parent;
u64 parent_gen;
int ret;
fs_path_reset(fs_path);
ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path);
if (ret < 0)
return ret;
if (parent == ino1)
return parent_gen == ino1_gen;
ino = parent;
}
return 0;
}
/*
* Check if ino ino1 is an ancestor of inode ino2 in the given root for any
* possible path (in case ino2 is not a directory and has multiple hard links).
* Return 1 if true, 0 if false and < 0 on error.
*/
static int is_ancestor(struct btrfs_root *root,
const u64 ino1,
const u64 ino1_gen,
const u64 ino2,
struct fs_path *fs_path)
{
bool free_fs_path = false;
int ret = 0;
struct btrfs_path *path = NULL;
struct btrfs_key key;
if (!fs_path) {
fs_path = fs_path_alloc();
if (!fs_path)
return -ENOMEM;
free_fs_path = true;
}
path = alloc_path_for_send();
if (!path) {
ret = -ENOMEM;
goto out;
}
key.objectid = ino2;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (true) {
struct extent_buffer *leaf = path->nodes[0];
int slot = path->slots[0];
u32 cur_offset = 0;
u32 item_size;
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != ino2)
break;
if (key.type != BTRFS_INODE_REF_KEY &&
key.type != BTRFS_INODE_EXTREF_KEY)
break;
item_size = btrfs_item_size(leaf, slot);
while (cur_offset < item_size) {
u64 parent;
u64 parent_gen;
if (key.type == BTRFS_INODE_EXTREF_KEY) {
unsigned long ptr;
struct btrfs_inode_extref *extref;
ptr = btrfs_item_ptr_offset(leaf, slot);
extref = (struct btrfs_inode_extref *)
(ptr + cur_offset);
parent = btrfs_inode_extref_parent(leaf,
extref);
cur_offset += sizeof(*extref);
cur_offset += btrfs_inode_extref_name_len(leaf,
extref);
} else {
parent = key.offset;
cur_offset = item_size;
}
ret = get_inode_info(root, parent, NULL, &parent_gen,
NULL, NULL, NULL, NULL);
if (ret < 0)
goto out;
ret = check_ino_in_path(root, ino1, ino1_gen,
parent, parent_gen, fs_path);
if (ret)
goto out;
}
path->slots[0]++;
}
ret = 0;
out:
btrfs_free_path(path);
if (free_fs_path)
fs_path_free(fs_path);
return ret;
}
static int wait_for_parent_move(struct send_ctx *sctx,
struct recorded_ref *parent_ref,
const bool is_orphan)
{
int ret = 0;
u64 ino = parent_ref->dir;
u64 ino_gen = parent_ref->dir_gen;
u64 parent_ino_before, parent_ino_after;
struct fs_path *path_before = NULL;
struct fs_path *path_after = NULL;
int len1, len2;
path_after = fs_path_alloc();
path_before = fs_path_alloc();
if (!path_after || !path_before) {
ret = -ENOMEM;
goto out;
}
/*
* Our current directory inode may not yet be renamed/moved because some
* ancestor (immediate or not) has to be renamed/moved first. So find if
* such ancestor exists and make sure our own rename/move happens after
* that ancestor is processed to avoid path build infinite loops (done
* at get_cur_path()).
*/
while (ino > BTRFS_FIRST_FREE_OBJECTID) {
u64 parent_ino_after_gen;
if (is_waiting_for_move(sctx, ino)) {
/*
* If the current inode is an ancestor of ino in the
* parent root, we need to delay the rename of the
* current inode, otherwise don't delayed the rename
* because we can end up with a circular dependency
* of renames, resulting in some directories never
* getting the respective rename operations issued in
* the send stream or getting into infinite path build
* loops.
*/
ret = is_ancestor(sctx->parent_root,
sctx->cur_ino, sctx->cur_inode_gen,
ino, path_before);
if (ret)
break;
}
fs_path_reset(path_before);
fs_path_reset(path_after);
ret = get_first_ref(sctx->send_root, ino, &parent_ino_after,
&parent_ino_after_gen, path_after);
if (ret < 0)
goto out;
ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before,
NULL, path_before);
if (ret < 0 && ret != -ENOENT) {
goto out;
} else if (ret == -ENOENT) {
ret = 0;
break;
}
len1 = fs_path_len(path_before);
len2 = fs_path_len(path_after);
if (ino > sctx->cur_ino &&
(parent_ino_before != parent_ino_after || len1 != len2 ||
memcmp(path_before->start, path_after->start, len1))) {
u64 parent_ino_gen;
ret = get_inode_info(sctx->parent_root, ino, NULL,
&parent_ino_gen, NULL, NULL, NULL,
NULL);
if (ret < 0)
goto out;
if (ino_gen == parent_ino_gen) {
ret = 1;
break;
}
}
ino = parent_ino_after;
ino_gen = parent_ino_after_gen;
}
out:
fs_path_free(path_before);
fs_path_free(path_after);
if (ret == 1) {
ret = add_pending_dir_move(sctx,
sctx->cur_ino,
sctx->cur_inode_gen,
ino,
&sctx->new_refs,
&sctx->deleted_refs,
is_orphan);
if (!ret)
ret = 1;
}
return ret;
}
static int update_ref_path(struct send_ctx *sctx, struct recorded_ref *ref)
{
int ret;
struct fs_path *new_path;
/*
* Our reference's name member points to its full_path member string, so
* we use here a new path.
*/
new_path = fs_path_alloc();
if (!new_path)
return -ENOMEM;
ret = get_cur_path(sctx, ref->dir, ref->dir_gen, new_path);
if (ret < 0) {
fs_path_free(new_path);
return ret;
}
ret = fs_path_add(new_path, ref->name, ref->name_len);
if (ret < 0) {
fs_path_free(new_path);
return ret;
}
fs_path_free(ref->full_path);
set_ref_path(ref, new_path);
return 0;
}
/*
* When processing the new references for an inode we may orphanize an existing
* directory inode because its old name conflicts with one of the new references
* of the current inode. Later, when processing another new reference of our
* inode, we might need to orphanize another inode, but the path we have in the
* reference reflects the pre-orphanization name of the directory we previously
* orphanized. For example:
*
* parent snapshot looks like:
*
* . (ino 256)
* |----- f1 (ino 257)
* |----- f2 (ino 258)
* |----- d1/ (ino 259)
* |----- d2/ (ino 260)
*
* send snapshot looks like:
*
* . (ino 256)
* |----- d1 (ino 258)
* |----- f2/ (ino 259)
* |----- f2_link/ (ino 260)
* | |----- f1 (ino 257)
* |
* |----- d2 (ino 258)
*
* When processing inode 257 we compute the name for inode 259 as "d1", and we
* cache it in the name cache. Later when we start processing inode 258, when
* collecting all its new references we set a full path of "d1/d2" for its new
* reference with name "d2". When we start processing the new references we
* start by processing the new reference with name "d1", and this results in
* orphanizing inode 259, since its old reference causes a conflict. Then we
* move on the next new reference, with name "d2", and we find out we must
* orphanize inode 260, as its old reference conflicts with ours - but for the
* orphanization we use a source path corresponding to the path we stored in the
* new reference, which is "d1/d2" and not "o259-6-0/d2" - this makes the
* receiver fail since the path component "d1/" no longer exists, it was renamed
* to "o259-6-0/" when processing the previous new reference. So in this case we
* must recompute the path in the new reference and use it for the new
* orphanization operation.
*/
static int refresh_ref_path(struct send_ctx *sctx, struct recorded_ref *ref)
{
char *name;
int ret;
name = kmemdup(ref->name, ref->name_len, GFP_KERNEL);
if (!name)
return -ENOMEM;
fs_path_reset(ref->full_path);
ret = get_cur_path(sctx, ref->dir, ref->dir_gen, ref->full_path);
if (ret < 0)
goto out;
ret = fs_path_add(ref->full_path, name, ref->name_len);
if (ret < 0)
goto out;
/* Update the reference's base name pointer. */
set_ref_path(ref, ref->full_path);
out:
kfree(name);
return ret;
}
/*
* This does all the move/link/unlink/rmdir magic.
*/
static int process_recorded_refs(struct send_ctx *sctx, int *pending_move)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct recorded_ref *cur;
struct recorded_ref *cur2;
struct list_head check_dirs;
struct fs_path *valid_path = NULL;
u64 ow_inode = 0;
u64 ow_gen;
u64 ow_mode;
int did_overwrite = 0;
int is_orphan = 0;
u64 last_dir_ino_rm = 0;
bool can_rename = true;
bool orphanized_dir = false;
bool orphanized_ancestor = false;
btrfs_debug(fs_info, "process_recorded_refs %llu", sctx->cur_ino);
/*
* 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);
INIT_LIST_HEAD(&check_dirs);
valid_path = fs_path_alloc();
if (!valid_path) {
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;
}
/*
* Before doing any rename and link operations, do a first pass on the
* new references to orphanize any unprocessed inodes that may have a
* reference that conflicts with one of the new references of the current
* inode. This needs to happen first because a new reference may conflict
* with the old reference of a parent directory, so we must make sure
* that the path used for link and rename commands don't use an
* orphanized name when an ancestor was not yet orphanized.
*
* Example:
*
* Parent snapshot:
*
* . (ino 256)
* |----- testdir/ (ino 259)
* | |----- a (ino 257)
* |
* |----- b (ino 258)
*
* Send snapshot:
*
* . (ino 256)
* |----- testdir_2/ (ino 259)
* | |----- a (ino 260)
* |
* |----- testdir (ino 257)
* |----- b (ino 257)
* |----- b2 (ino 258)
*
* Processing the new reference for inode 257 with name "b" may happen
* before processing the new reference with name "testdir". If so, we
* must make sure that by the time we send a link command to create the
* hard link "b", inode 259 was already orphanized, since the generated
* path in "valid_path" already contains the orphanized name for 259.
* We are processing inode 257, so only later when processing 259 we do
* the rename operation to change its temporary (orphanized) name to
* "testdir_2".
*/
list_for_each_entry(cur, &sctx->new_refs, list) {
ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
if (ret < 0)
goto out;
if (ret == inode_state_will_create)
continue;
/*
* 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, &ow_mode);
if (ret < 0)
goto out;
if (ret) {
ret = is_first_ref(sctx->parent_root,
ow_inode, cur->dir, cur->name,
cur->name_len);
if (ret < 0)
goto out;
if (ret) {
struct name_cache_entry *nce;
struct waiting_dir_move *wdm;
if (orphanized_dir) {
ret = refresh_ref_path(sctx, cur);
if (ret < 0)
goto out;
}
ret = orphanize_inode(sctx, ow_inode, ow_gen,
cur->full_path);
if (ret < 0)
goto out;
if (S_ISDIR(ow_mode))
orphanized_dir = true;
/*
* If ow_inode has its rename operation delayed
* make sure that its orphanized name is used in
* the source path when performing its rename
* operation.
*/
if (is_waiting_for_move(sctx, ow_inode)) {
wdm = get_waiting_dir_move(sctx,
ow_inode);
ASSERT(wdm);
wdm->orphanized = true;
}
/*
* Make sure we clear our orphanized inode's
* name from the name cache. This is because the
* inode ow_inode might be an ancestor of some
* other inode that will be orphanized as well
* later and has an inode number greater than
* sctx->send_progress. We need to prevent
* future name lookups from using the old name
* and get instead the orphan name.
*/
nce = name_cache_search(sctx, ow_inode, ow_gen);
if (nce) {
name_cache_delete(sctx, nce);
kfree(nce);
}
/*
* ow_inode might currently be an ancestor of
* cur_ino, therefore compute valid_path (the
* current path of cur_ino) again because it
* might contain the pre-orphanization name of
* ow_inode, which is no longer valid.
*/
ret = is_ancestor(sctx->parent_root,
ow_inode, ow_gen,
sctx->cur_ino, NULL);
if (ret > 0) {
orphanized_ancestor = true;
fs_path_reset(valid_path);
ret = get_cur_path(sctx, sctx->cur_ino,
sctx->cur_inode_gen,
valid_path);
}
if (ret < 0)
goto out;
} else {
/*
* If we previously orphanized a directory that
* collided with a new reference that we already
* processed, recompute the current path because
* that directory may be part of the path.
*/
if (orphanized_dir) {
ret = refresh_ref_path(sctx, cur);
if (ret < 0)
goto out;
}
ret = send_unlink(sctx, cur->full_path);
if (ret < 0)
goto out;
}
}
}
list_for_each_entry(cur, &sctx->new_refs, list) {
/*
* We may have refs where the parent directory does not exist
* yet. This happens if the parent directories inum is higher
* than 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;
}
}
if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root) {
ret = wait_for_dest_dir_move(sctx, cur, is_orphan);
if (ret < 0)
goto out;
if (ret == 1) {
can_rename = false;
*pending_move = 1;
}
}
if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root &&
can_rename) {
ret = wait_for_parent_move(sctx, cur, is_orphan);
if (ret < 0)
goto out;
if (ret == 1) {
can_rename = false;
*pending_move = 1;
}
}
/*
* 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.
*/
if (is_orphan && can_rename) {
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 (can_rename) {
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)
ret = fs_path_copy(valid_path,
cur->full_path);
if (ret < 0)
goto out;
} else {
/*
* We might have previously orphanized an inode
* which is an ancestor of our current inode,
* so our reference's full path, which was
* computed before any such orphanizations, must
* be updated.
*/
if (orphanized_dir) {
ret = update_ref_path(sctx, cur);
if (ret < 0)
goto out;
}
ret = send_link(sctx, cur->full_path,
valid_path);
if (ret < 0)
goto out;
}
}
ret = dup_ref(cur, &check_dirs);
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_inode_gen,
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 = dup_ref(cur, &check_dirs);
if (ret < 0)
goto out;
}
} 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 = dup_ref(cur, &check_dirs);
if (ret < 0)
goto out;
} 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) {
/*
* If we orphanized any ancestor before, we need
* to recompute the full path for deleted names,
* since any such path was computed before we
* processed any references and orphanized any
* ancestor inode.
*/
if (orphanized_ancestor) {
ret = update_ref_path(sctx, cur);
if (ret < 0)
goto out;
}
ret = send_unlink(sctx, cur->full_path);
if (ret < 0)
goto out;
}
ret = dup_ref(cur, &check_dirs);
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
* inode. Unlinking does not mean that the inode is deleted in
* all cases. There may still be links to this inode in other
* places.
*/
if (is_orphan) {
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.
*/
list_for_each_entry(cur, &check_dirs, list) {
/*
* 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.
*/
if (cur->dir > sctx->cur_ino)
continue;
ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
if (ret < 0)
goto out;
if (ret == inode_state_did_create ||
ret == inode_state_no_change) {
/* TODO delayed utimes */
ret = send_utimes(sctx, cur->dir, cur->dir_gen);
if (ret < 0)
goto out;
} else if (ret == inode_state_did_delete &&
cur->dir != last_dir_ino_rm) {
ret = can_rmdir(sctx, cur->dir, cur->dir_gen,
sctx->cur_ino);
if (ret < 0)
goto out;
if (ret) {
ret = get_cur_path(sctx, cur->dir,
cur->dir_gen, valid_path);
if (ret < 0)
goto out;
ret = send_rmdir(sctx, valid_path);
if (ret < 0)
goto out;
last_dir_ino_rm = cur->dir;
}
}
}
ret = 0;
out:
__free_recorded_refs(&check_dirs);
free_recorded_refs(sctx);
fs_path_free(valid_path);
return ret;
}
static int record_ref(struct btrfs_root *root, u64 dir, struct fs_path *name,
void *ctx, struct list_head *refs)
{
int ret = 0;
struct send_ctx *sctx = ctx;
struct fs_path *p;
u64 gen;
p = fs_path_alloc();
if (!p)
return -ENOMEM;
ret = get_inode_info(root, dir, NULL, &gen, NULL, NULL,
NULL, NULL);
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(refs, dir, gen, p);
out:
if (ret)
fs_path_free(p);
return ret;
}
static int __record_new_ref(int num, u64 dir, int index,
struct fs_path *name,
void *ctx)
{
struct send_ctx *sctx = ctx;
return record_ref(sctx->send_root, dir, name, ctx, &sctx->new_refs);
}
static int __record_deleted_ref(int num, u64 dir, int index,
struct fs_path *name,
void *ctx)
{
struct send_ctx *sctx = ctx;
return record_ref(sctx->parent_root, dir, name, ctx,
&sctx->deleted_refs);
}
static int record_new_ref(struct send_ctx *sctx)
{
int ret;
ret = iterate_inode_ref(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->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;
u64 dir_gen;
struct btrfs_root *root;
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_;
u64 dir_gen;
int ret;
if (dir == ctx->dir && fs_path_len(name) == fs_path_len(ctx->name) &&
strncmp(name->start, ctx->name->start, fs_path_len(name)) == 0) {
/*
* To avoid doing extra lookups we'll only do this if everything
* else matches.
*/
ret = get_inode_info(ctx->root, dir, NULL, &dir_gen, NULL,
NULL, NULL, NULL);
if (ret)
return ret;
if (dir_gen != ctx->dir_gen)
return 0;
ctx->found_idx = num;
return 1;
}
return 0;
}
static int find_iref(struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *key,
u64 dir, u64 dir_gen, struct fs_path *name)
{
int ret;
struct find_ref_ctx ctx;
ctx.dir = dir;
ctx.name = name;
ctx.dir_gen = dir_gen;
ctx.found_idx = -1;
ctx.root = root;
ret = iterate_inode_ref(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)
{
u64 dir_gen;
int ret;
struct send_ctx *sctx = ctx;
ret = get_inode_info(sctx->send_root, dir, NULL, &dir_gen, NULL,
NULL, NULL, NULL);
if (ret)
return ret;
ret = find_iref(sctx->parent_root, sctx->right_path,
sctx->cmp_key, dir, dir_gen, 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)
{
u64 dir_gen;
int ret;
struct send_ctx *sctx = ctx;
ret = get_inode_info(sctx->parent_root, dir, NULL, &dir_gen, NULL,
NULL, NULL, NULL);
if (ret)
return ret;
ret = find_iref(sctx->send_root, sctx->left_path, sctx->cmp_key,
dir, dir_gen, 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->send_root, sctx->left_path,
sctx->cmp_key, 0, __record_changed_new_ref, sctx);
if (ret < 0)
goto out;
ret = iterate_inode_ref(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;
int pending_move = 0;
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 {
btrfs_err(sctx->send_root->fs_info,
"Wrong command %d in process_all_refs", cmd);
ret = -EINVAL;
goto out;
}
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
(found_key.type != BTRFS_INODE_REF_KEY &&
found_key.type != BTRFS_INODE_EXTREF_KEY))
break;
ret = iterate_inode_ref(root, path, &found_key, 0, cb, sctx);
if (ret < 0)
goto out;
path->slots[0]++;
}
btrfs_release_path(path);
/*
* We don't actually care about pending_move as we are simply
* re-creating this inode and will be rename'ing it into place once we
* rename the parent directory.
*/
ret = process_recorded_refs(sctx, &pending_move);
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, void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
struct fs_path *p;
struct posix_acl_xattr_header dummy_acl;
/* Capabilities are emitted by finish_inode_if_needed */
if (!strncmp(name, XATTR_NAME_CAPS, name_len))
return 0;
p = fs_path_alloc();
if (!p)
return -ENOMEM;
/*
* This hack is needed because empty acls are stored as zero byte
* data in xattrs. Problem with that is, that receiving these zero byte
* acls 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(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, void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
struct fs_path *p;
p = fs_path_alloc();
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(p);
return ret;
}
static int process_new_xattr(struct send_ctx *sctx)
{
int ret = 0;
ret = iterate_dir_item(sctx->send_root, sctx->left_path,
__process_new_xattr, sctx);
return ret;
}
static int process_deleted_xattr(struct send_ctx *sctx)
{
return iterate_dir_item(sctx->parent_root, sctx->right_path,
__process_deleted_xattr, sctx);
}
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, 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 = kmemdup(data, data_len, GFP_KERNEL);
if (!ctx->found_data)
return -ENOMEM;
return 1;
}
return 0;
}
static int find_xattr(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(root, path, __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,
void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
char *found_data = NULL;
int found_data_len = 0;
ret = find_xattr(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, 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, ctx);
} else {
ret = 0;
}
}
kfree(found_data);
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,
void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
ret = find_xattr(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, 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->send_root, sctx->left_path,
__process_changed_new_xattr, sctx);
if (ret < 0)
goto out;
ret = iterate_dir_item(sctx->parent_root, sctx->right_path,
__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;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
break;
}
continue;
}
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(root, path, __process_new_xattr, sctx);
if (ret < 0)
goto out;
path->slots[0]++;
}
out:
btrfs_free_path(path);
return ret;
}
static inline u64 max_send_read_size(const struct send_ctx *sctx)
{
return sctx->send_max_size - SZ_16K;
}
static int put_data_header(struct send_ctx *sctx, u32 len)
{
struct btrfs_tlv_header *hdr;
if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len)
return -EOVERFLOW;
hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size);
put_unaligned_le16(BTRFS_SEND_A_DATA, &hdr->tlv_type);
put_unaligned_le16(len, &hdr->tlv_len);
sctx->send_size += sizeof(*hdr);
return 0;
}
static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
{
struct btrfs_root *root = sctx->send_root;
struct btrfs_fs_info *fs_info = root->fs_info;
struct inode *inode;
struct page *page;
pgoff_t index = offset >> PAGE_SHIFT;
pgoff_t last_index;
unsigned pg_offset = offset_in_page(offset);
int ret;
ret = put_data_header(sctx, len);
if (ret)
return ret;
inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root);
if (IS_ERR(inode))
return PTR_ERR(inode);
last_index = (offset + len - 1) >> PAGE_SHIFT;
/* initial readahead */
memset(&sctx->ra, 0, sizeof(struct file_ra_state));
file_ra_state_init(&sctx->ra, inode->i_mapping);
while (index <= last_index) {
unsigned cur_len = min_t(unsigned, len,
PAGE_SIZE - pg_offset);
page = find_lock_page(inode->i_mapping, index);
if (!page) {
page_cache_sync_readahead(inode->i_mapping, &sctx->ra,
NULL, index, last_index + 1 - index);
page = find_or_create_page(inode->i_mapping, index,
GFP_KERNEL);
if (!page) {
ret = -ENOMEM;
break;
}
}
if (PageReadahead(page)) {
page_cache_async_readahead(inode->i_mapping, &sctx->ra,
NULL, page, index, last_index + 1 - index);
}
if (!PageUptodate(page)) {
btrfs_readpage(NULL, page);
lock_page(page);
if (!PageUptodate(page)) {
unlock_page(page);
btrfs_err(fs_info,
"send: IO error at offset %llu for inode %llu root %llu",
page_offset(page), sctx->cur_ino,
sctx->send_root->root_key.objectid);
put_page(page);
ret = -EIO;
break;
}
}
memcpy_from_page(sctx->send_buf + sctx->send_size, page,
pg_offset, cur_len);
unlock_page(page);
put_page(page);
index++;
pg_offset = 0;
len -= cur_len;
sctx->send_size += cur_len;
}
iput(inode);
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)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
p = fs_path_alloc();
if (!p)
return -ENOMEM;
btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len);
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);
ret = put_file_data(sctx, offset, len);
if (ret < 0)
goto out;
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(p);
return ret;
}
/*
* 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;
btrfs_debug(sctx->send_root->fs_info,
"send_clone offset=%llu, len=%d, clone_root=%llu, clone_inode=%llu, clone_offset=%llu",
offset, len, clone_root->root->root_key.objectid,
clone_root->ino, clone_root->offset);
p = fs_path_alloc();
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);
if (clone_root->root == sctx->send_root) {
ret = get_inode_info(sctx->send_root, clone_root->ino, NULL,
&gen, NULL, NULL, NULL, NULL);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, clone_root->ino, gen, p);
} else {
ret = get_inode_path(clone_root->root, clone_root->ino, p);
}
if (ret < 0)
goto out;
/*
* If the parent we're using has a received_uuid set then use that as
* our clone source as that is what we will look for when doing a
* receive.
*
* This covers the case that we create a snapshot off of a received
* subvolume and then use that as the parent and try to receive on a
* different host.
*/
if (!btrfs_is_empty_uuid(clone_root->root->root_item.received_uuid))
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
clone_root->root->root_item.received_uuid);
else
TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID,
clone_root->root->root_item.uuid);
TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID,
btrfs_root_ctransid(&clone_root->root->root_item));
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(p);
return ret;
}
/*
* Send an update extent command to user space.
*/
static int send_update_extent(struct send_ctx *sctx,
u64 offset, u32 len)
{
int ret = 0;
struct fs_path *p;
p = fs_path_alloc();
if (!p)
return -ENOMEM;
ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT);
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);
TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len);
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(p);
return ret;
}
static int send_hole(struct send_ctx *sctx, u64 end)
{
struct fs_path *p = NULL;
u64 read_size = max_send_read_size(sctx);
u64 offset = sctx->cur_inode_last_extent;
int ret = 0;
/*
* A hole that starts at EOF or beyond it. Since we do not yet support
* fallocate (for extent preallocation and hole punching), sending a
* write of zeroes starting at EOF or beyond would later require issuing
* a truncate operation which would undo the write and achieve nothing.
*/
if (offset >= sctx->cur_inode_size)
return 0;
/*
* Don't go beyond the inode's i_size due to prealloc extents that start
* after the i_size.
*/
end = min_t(u64, end, sctx->cur_inode_size);
if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
return send_update_extent(sctx, offset, end - offset);
p = fs_path_alloc();
if (!p)
return -ENOMEM;
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
if (ret < 0)
goto tlv_put_failure;
while (offset < end) {
u64 len = min(end - offset, read_size);
ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
if (ret < 0)
break;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
ret = put_data_header(sctx, len);
if (ret < 0)
break;
memset(sctx->send_buf + sctx->send_size, 0, len);
sctx->send_size += len;
ret = send_cmd(sctx);
if (ret < 0)
break;
offset += len;
}
sctx->cur_inode_next_write_offset = offset;
tlv_put_failure:
fs_path_free(p);
return ret;
}
static int send_extent_data(struct send_ctx *sctx,
const u64 offset,
const u64 len)
{
u64 read_size = max_send_read_size(sctx);
u64 sent = 0;
if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
return send_update_extent(sctx, offset, len);
while (sent < len) {
u64 size = min(len - sent, read_size);
int ret;
ret = send_write(sctx, offset + sent, size);
if (ret < 0)
return ret;
sent += size;
}
return 0;
}
/*
* Search for a capability xattr related to sctx->cur_ino. If the capability is
* found, call send_set_xattr function to emit it.
*
* Return 0 if there isn't a capability, or when the capability was emitted
* successfully, or < 0 if an error occurred.
*/
static int send_capabilities(struct send_ctx *sctx)
{
struct fs_path *fspath = NULL;
struct btrfs_path *path;
struct btrfs_dir_item *di;
struct extent_buffer *leaf;
unsigned long data_ptr;
char *buf = NULL;
int buf_len;
int ret = 0;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
di = btrfs_lookup_xattr(NULL, sctx->send_root, path, sctx->cur_ino,
XATTR_NAME_CAPS, strlen(XATTR_NAME_CAPS), 0);
if (!di) {
/* There is no xattr for this inode */
goto out;
} else if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out;
}
leaf = path->nodes[0];
buf_len = btrfs_dir_data_len(leaf, di);
fspath = fs_path_alloc();
buf = kmalloc(buf_len, GFP_KERNEL);
if (!fspath || !buf) {
ret = -ENOMEM;
goto out;
}
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath);
if (ret < 0)
goto out;
data_ptr = (unsigned long)(di + 1) + btrfs_dir_name_len(leaf, di);
read_extent_buffer(leaf, buf, data_ptr, buf_len);
ret = send_set_xattr(sctx, fspath, XATTR_NAME_CAPS,
strlen(XATTR_NAME_CAPS), buf, buf_len);
out:
kfree(buf);
fs_path_free(fspath);
btrfs_free_path(path);
return ret;
}
static int clone_range(struct send_ctx *sctx,
struct clone_root *clone_root,
const u64 disk_byte,
u64 data_offset,
u64 offset,
u64 len)
{
struct btrfs_path *path;
struct btrfs_key key;
int ret;
u64 clone_src_i_size = 0;
/*
* Prevent cloning from a zero offset with a length matching the sector
* size because in some scenarios this will make the receiver fail.
*
* For example, if in the source filesystem the extent at offset 0
* has a length of sectorsize and it was written using direct IO, then
* it can never be an inline extent (even if compression is enabled).
* Then this extent can be cloned in the original filesystem to a non
* zero file offset, but it may not be possible to clone in the
* destination filesystem because it can be inlined due to compression
* on the destination filesystem (as the receiver's write operations are
* always done using buffered IO). The same happens when the original
* filesystem does not have compression enabled but the destination
* filesystem has.
*/
if (clone_root->offset == 0 &&
len == sctx->send_root->fs_info->sectorsize)
return send_extent_data(sctx, offset, len);
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
/*
* There are inodes that have extents that lie behind its i_size. Don't
* accept clones from these extents.
*/
ret = __get_inode_info(clone_root->root, path, clone_root->ino,
&clone_src_i_size, NULL, NULL, NULL, NULL, NULL);
btrfs_release_path(path);
if (ret < 0)
goto out;
/*
* We can't send a clone operation for the entire range if we find
* extent items in the respective range in the source file that
* refer to different extents or if we find holes.
* So check for that and do a mix of clone and regular write/copy
* operations if needed.
*
* Example:
*
* mkfs.btrfs -f /dev/sda
* mount /dev/sda /mnt
* xfs_io -f -c "pwrite -S 0xaa 0K 100K" /mnt/foo
* cp --reflink=always /mnt/foo /mnt/bar
* xfs_io -c "pwrite -S 0xbb 50K 50K" /mnt/foo
* btrfs subvolume snapshot -r /mnt /mnt/snap
*
* If when we send the snapshot and we are processing file bar (which
* has a higher inode number than foo) we blindly send a clone operation
* for the [0, 100K[ range from foo to bar, the receiver ends up getting
* a file bar that matches the content of file foo - iow, doesn't match
* the content from bar in the original filesystem.
*/
key.objectid = clone_root->ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = clone_root->offset;
ret = btrfs_search_slot(NULL, clone_root->root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret > 0 && path->slots[0] > 0) {
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1);
if (key.objectid == clone_root->ino &&
key.type == BTRFS_EXTENT_DATA_KEY)
path->slots[0]--;
}
while (true) {
struct extent_buffer *leaf = path->nodes[0];
int slot = path->slots[0];
struct btrfs_file_extent_item *ei;
u8 type;
u64 ext_len;
u64 clone_len;
u64 clone_data_offset;
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(clone_root->root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(leaf, &key, slot);
/*
* We might have an implicit trailing hole (NO_HOLES feature
* enabled). We deal with it after leaving this loop.
*/
if (key.objectid != clone_root->ino ||
key.type != BTRFS_EXTENT_DATA_KEY)
break;
ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
type = btrfs_file_extent_type(leaf, ei);
if (type == BTRFS_FILE_EXTENT_INLINE) {
ext_len = btrfs_file_extent_ram_bytes(leaf, ei);
ext_len = PAGE_ALIGN(ext_len);
} else {
ext_len = btrfs_file_extent_num_bytes(leaf, ei);
}
if (key.offset + ext_len <= clone_root->offset)
goto next;
if (key.offset > clone_root->offset) {
/* Implicit hole, NO_HOLES feature enabled. */
u64 hole_len = key.offset - clone_root->offset;
if (hole_len > len)
hole_len = len;
ret = send_extent_data(sctx, offset, hole_len);
if (ret < 0)
goto out;
len -= hole_len;
if (len == 0)
break;
offset += hole_len;
clone_root->offset += hole_len;
data_offset += hole_len;
}
if (key.offset >= clone_root->offset + len)
break;
if (key.offset >= clone_src_i_size)
break;
if (key.offset + ext_len > clone_src_i_size)
ext_len = clone_src_i_size - key.offset;
clone_data_offset = btrfs_file_extent_offset(leaf, ei);
if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte) {
clone_root->offset = key.offset;
if (clone_data_offset < data_offset &&
clone_data_offset + ext_len > data_offset) {
u64 extent_offset;
extent_offset = data_offset - clone_data_offset;
ext_len -= extent_offset;
clone_data_offset += extent_offset;
clone_root->offset += extent_offset;
}
}
clone_len = min_t(u64, ext_len, len);
if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte &&
clone_data_offset == data_offset) {
const u64 src_end = clone_root->offset + clone_len;
const u64 sectorsize = SZ_64K;
/*
* We can't clone the last block, when its size is not
* sector size aligned, into the middle of a file. If we
* do so, the receiver will get a failure (-EINVAL) when
* trying to clone or will silently corrupt the data in
* the destination file if it's on a kernel without the
* fix introduced by commit ac765f83f1397646
* ("Btrfs: fix data corruption due to cloning of eof
* block).
*
* So issue a clone of the aligned down range plus a
* regular write for the eof block, if we hit that case.
*
* Also, we use the maximum possible sector size, 64K,
* because we don't know what's the sector size of the
* filesystem that receives the stream, so we have to
* assume the largest possible sector size.
*/
if (src_end == clone_src_i_size &&
!IS_ALIGNED(src_end, sectorsize) &&
offset + clone_len < sctx->cur_inode_size) {
u64 slen;
slen = ALIGN_DOWN(src_end - clone_root->offset,
sectorsize);
if (slen > 0) {
ret = send_clone(sctx, offset, slen,
clone_root);
if (ret < 0)
goto out;
}
ret = send_extent_data(sctx, offset + slen,
clone_len - slen);
} else {
ret = send_clone(sctx, offset, clone_len,
clone_root);
}
} else {
ret = send_extent_data(sctx, offset, clone_len);
}
if (ret < 0)
goto out;
len -= clone_len;
if (len == 0)
break;
offset += clone_len;
clone_root->offset += clone_len;
/*
* If we are cloning from the file we are currently processing,
* and using the send root as the clone root, we must stop once
* the current clone offset reaches the current eof of the file
* at the receiver, otherwise we would issue an invalid clone
* operation (source range going beyond eof) and cause the
* receiver to fail. So if we reach the current eof, bail out
* and fallback to a regular write.
*/
if (clone_root->root == sctx->send_root &&
clone_root->ino == sctx->cur_ino &&
clone_root->offset >= sctx->cur_inode_next_write_offset)
break;
data_offset += clone_len;
next:
path->slots[0]++;
}
if (len > 0)
ret = send_extent_data(sctx, offset, len);
else
ret = 0;
out:
btrfs_free_path(path);
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;
u64 offset = key->offset;
u64 end;
u64 bs = sctx->send_root->fs_info->sb->s_blocksize;
end = min_t(u64, btrfs_file_extent_end(path), sctx->cur_inode_size);
if (offset >= end)
return 0;
if (clone_root && IS_ALIGNED(end, bs)) {
struct btrfs_file_extent_item *ei;
u64 disk_byte;
u64 data_offset;
ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_file_extent_item);
disk_byte = btrfs_file_extent_disk_bytenr(path->nodes[0], ei);
data_offset = btrfs_file_extent_offset(path->nodes[0], ei);
ret = clone_range(sctx, clone_root, disk_byte, data_offset,
offset, end - offset);
} else {
ret = send_extent_data(sctx, offset, end - offset);
}
sctx->cur_inode_next_write_offset = end;
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;
u64 left_gen;
u64 right_gen;
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;
}
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);
/*
* 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) {
/* If we're a hole then just pretend nothing changed */
ret = (left_disknr) ? 0 : 1;
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);
if (right_type != BTRFS_FILE_EXTENT_REG &&
right_type != BTRFS_FILE_EXTENT_INLINE) {
ret = 0;
goto out;
}
if (right_type == BTRFS_FILE_EXTENT_INLINE) {
right_len = btrfs_file_extent_ram_bytes(eb, ei);
right_len = PAGE_ALIGN(right_len);
} else {
right_len = btrfs_file_extent_num_bytes(eb, ei);
}
/*
* Are we at extent 8? If yes, we know the extent is changed.
* This may only happen on the first iteration.
*/
if (found_key.offset + right_len <= ekey->offset) {
/* If we're a hole just pretend nothing changed */
ret = (left_disknr) ? 0 : 1;
goto out;
}
/*
* We just wanted to see if when we have an inline extent, what
* follows it is a regular extent (wanted to check the above
* condition for inline extents too). This should normally not
* happen but it's possible for example when we have an inline
* compressed extent representing data with a size matching
* the page size (currently the same as sector size).
*/
if (right_type == BTRFS_FILE_EXTENT_INLINE) {
ret = 0;
goto out;
}
right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
right_offset = btrfs_file_extent_offset(eb, ei);
right_gen = btrfs_file_extent_generation(eb, ei);
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.
*/
if (left_disknr != right_disknr ||
left_offset_fixed != right_offset ||
left_gen != right_gen) {
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;
}
if (found_key.offset != key.offset + right_len) {
ret = 0;
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 get_last_extent(struct send_ctx *sctx, u64 offset)
{
struct btrfs_path *path;
struct btrfs_root *root = sctx->send_root;
struct btrfs_key key;
int ret;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
sctx->cur_inode_last_extent = 0;
key.objectid = sctx->cur_ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = offset;
ret = btrfs_search_slot_for_read(root, &key, path, 0, 1);
if (ret < 0)
goto out;
ret = 0;
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if (key.objectid != sctx->cur_ino || key.type != BTRFS_EXTENT_DATA_KEY)
goto out;
sctx->cur_inode_last_extent = btrfs_file_extent_end(path);
out:
btrfs_free_path(path);
return ret;
}
static int range_is_hole_in_parent(struct send_ctx *sctx,
const u64 start,
const u64 end)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_root *root = sctx->parent_root;
u64 search_start = start;
int ret;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = sctx->cur_ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = search_start;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret > 0 && path->slots[0] > 0)
path->slots[0]--;
while (search_start < end) {
struct extent_buffer *leaf = path->nodes[0];
int slot = path->slots[0];
struct btrfs_file_extent_item *fi;
u64 extent_end;
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid < sctx->cur_ino ||
key.type < BTRFS_EXTENT_DATA_KEY)
goto next;
if (key.objectid > sctx->cur_ino ||
key.type > BTRFS_EXTENT_DATA_KEY ||
key.offset >= end)
break;
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
extent_end = btrfs_file_extent_end(path);
if (extent_end <= start)
goto next;
if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) {
search_start = extent_end;
goto next;
}
ret = 0;
goto out;
next:
path->slots[0]++;
}
ret = 1;
out:
btrfs_free_path(path);
return ret;
}
static int maybe_send_hole(struct send_ctx *sctx, struct btrfs_path *path,
struct btrfs_key *key)
{
int ret = 0;
if (sctx->cur_ino != key->objectid || !need_send_hole(sctx))
return 0;
if (sctx->cur_inode_last_extent == (u64)-1) {
ret = get_last_extent(sctx, key->offset - 1);
if (ret)
return ret;
}
if (path->slots[0] == 0 &&
sctx->cur_inode_last_extent < key->offset) {
/*
* We might have skipped entire leafs that contained only
* file extent items for our current inode. These leafs have
* a generation number smaller (older) than the one in the
* current leaf and the leaf our last extent came from, and
* are located between these 2 leafs.
*/
ret = get_last_extent(sctx, key->offset - 1);
if (ret)
return ret;
}
if (sctx->cur_inode_last_extent < key->offset) {
ret = range_is_hole_in_parent(sctx,
sctx->cur_inode_last_extent,
key->offset);
if (ret < 0)
return ret;
else if (ret == 0)
ret = send_hole(sctx, key->offset);
else
ret = 0;
}
sctx->cur_inode_last_extent = btrfs_file_extent_end(path);
return ret;
}
static int process_extent(struct send_ctx *sctx,
struct btrfs_path *path,
struct btrfs_key *key)
{
struct clone_root *found_clone = NULL;
int ret = 0;
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_hole;
}
} else {
struct btrfs_file_extent_item *ei;
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);
if (type == BTRFS_FILE_EXTENT_PREALLOC ||
type == BTRFS_FILE_EXTENT_REG) {
/*
* The send spec does not have a prealloc command yet,
* so just leave a hole for prealloc'ed extents until
* we have enough commands queued up to justify rev'ing
* the send spec.
*/
if (type == BTRFS_FILE_EXTENT_PREALLOC) {
ret = 0;
goto out;
}
/* Have a hole, just skip it. */
if (btrfs_file_extent_disk_bytenr(path->nodes[0], ei) == 0) {
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);
if (ret)
goto out;
out_hole:
ret = maybe_send_hole(sctx, path, key);
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;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
break;
}
continue;
}
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;
path->slots[0]++;
}
out:
btrfs_free_path(path);
return ret;
}
static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end,
int *pending_move,
int *refs_processed)
{
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_EXTREF_KEY)
goto out;
if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs))
goto out;
ret = process_recorded_refs(sctx, pending_move);
if (ret < 0)
goto out;
*refs_processed = 1;
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;
int need_truncate = 1;
int pending_move = 0;
int refs_processed = 0;
if (sctx->ignore_cur_inode)
return 0;
ret = process_recorded_refs_if_needed(sctx, at_end, &pending_move,
&refs_processed);
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.
*
* On the other hand, if our current inode is a directory and couldn't
* be moved/renamed because its parent was renamed/moved too and it has
* a higher inode number, we can only move/rename our current inode
* after we moved/renamed its parent. Therefore in this case operate on
* the old path (pre move/rename) of our current inode, and the
* move/rename will be performed later.
*/
if (refs_processed && !pending_move)
sctx->send_progress = sctx->cur_ino + 1;
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,
&left_mode, &left_uid, &left_gid, NULL);
if (ret < 0)
goto out;
if (!sctx->parent_root || sctx->cur_inode_new) {
need_chown = 1;
if (!S_ISLNK(sctx->cur_inode_mode))
need_chmod = 1;
if (sctx->cur_inode_next_write_offset == sctx->cur_inode_size)
need_truncate = 0;
} else {
u64 old_size;
ret = get_inode_info(sctx->parent_root, sctx->cur_ino,
&old_size, NULL, &right_mode, &right_uid,
&right_gid, NULL);
if (ret < 0)
goto out;
if (left_uid != right_uid || left_gid != right_gid)
need_chown = 1;
if (!S_ISLNK(sctx->cur_inode_mode) && left_mode != right_mode)
need_chmod = 1;
if ((old_size == sctx->cur_inode_size) ||
(sctx->cur_inode_size > old_size &&
sctx->cur_inode_next_write_offset == sctx->cur_inode_size))
need_truncate = 0;
}
if (S_ISREG(sctx->cur_inode_mode)) {
if (need_send_hole(sctx)) {
if (sctx->cur_inode_last_extent == (u64)-1 ||
sctx->cur_inode_last_extent <
sctx->cur_inode_size) {
ret = get_last_extent(sctx, (u64)-1);
if (ret)
goto out;
}
if (sctx->cur_inode_last_extent <
sctx->cur_inode_size) {
ret = send_hole(sctx, sctx->cur_inode_size);
if (ret)
goto out;
}
}
if (need_truncate) {
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;
}
ret = send_capabilities(sctx);
if (ret < 0)
goto out;
/*
* If other directory inodes depended on our current directory
* inode's move/rename, now do their move/rename operations.
*/
if (!is_waiting_for_move(sctx, sctx->cur_ino)) {
ret = apply_children_dir_moves(sctx);
if (ret)
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. If our inode is a directory and it's
* waiting to be moved/renamed, we will send its utimes when
* it's moved/renamed, therefore we don't need to do it here.
*/
sctx->send_progress = sctx->cur_ino + 1;
ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen);
if (ret < 0)
goto out;
}
out:
return ret;
}
struct parent_paths_ctx {
struct list_head *refs;
struct send_ctx *sctx;
};
static int record_parent_ref(int num, u64 dir, int index, struct fs_path *name,
void *ctx)
{
struct parent_paths_ctx *ppctx = ctx;
return record_ref(ppctx->sctx->parent_root, dir, name, ppctx->sctx,
ppctx->refs);
}
/*
* Issue unlink operations for all paths of the current inode found in the
* parent snapshot.
*/
static int btrfs_unlink_all_paths(struct send_ctx *sctx)
{
LIST_HEAD(deleted_refs);
struct btrfs_path *path;
struct btrfs_key key;
struct parent_paths_ctx ctx;
int ret;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = sctx->cur_ino;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
ctx.refs = &deleted_refs;
ctx.sctx = sctx;
while (true) {
struct extent_buffer *eb = path->nodes[0];
int slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(sctx->parent_root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
btrfs_item_key_to_cpu(eb, &key, slot);
if (key.objectid != sctx->cur_ino)
break;
if (key.type != BTRFS_INODE_REF_KEY &&
key.type != BTRFS_INODE_EXTREF_KEY)
break;
ret = iterate_inode_ref(sctx->parent_root, path, &key, 1,
record_parent_ref, &ctx);
if (ret < 0)
goto out;
path->slots[0]++;
}
while (!list_empty(&deleted_refs)) {
struct recorded_ref *ref;
ref = list_first_entry(&deleted_refs, struct recorded_ref, list);
ret = send_unlink(sctx, ref->full_path);
if (ret < 0)
goto out;
fs_path_free(ref->full_path);
list_del(&ref->list);
kfree(ref);
}
ret = 0;
out:
btrfs_free_path(path);
if (ret)
__free_recorded_refs(&deleted_refs);
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;
sctx->cur_ino = key->objectid;
sctx->cur_inode_new_gen = 0;
sctx->cur_inode_last_extent = (u64)-1;
sctx->cur_inode_next_write_offset = 0;
sctx->ignore_cur_inode = false;
/*
* 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.
*/
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);
/*
* 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)
sctx->cur_inode_new_gen = 1;
}
/*
* Normally we do not find inodes with a link count of zero (orphans)
* because the most common case is to create a snapshot and use it
* for a send operation. However other less common use cases involve
* using a subvolume and send it after turning it to RO mode just
* after deleting all hard links of a file while holding an open
* file descriptor against it or turning a RO snapshot into RW mode,
* keep an open file descriptor against a file, delete it and then
* turn the snapshot back to RO mode before using it for a send
* operation. So if we find such cases, ignore the inode and all its
* items completely if it's a new inode, or if it's a changed inode
* make sure all its previous paths (from the parent snapshot) are all
* unlinked and all other the inode items are ignored.
*/
if (result == BTRFS_COMPARE_TREE_NEW ||
result == BTRFS_COMPARE_TREE_CHANGED) {
u32 nlinks;
nlinks = btrfs_inode_nlink(sctx->left_path->nodes[0], left_ii);
if (nlinks == 0) {
sctx->ignore_cur_inode = true;
if (result == BTRFS_COMPARE_TREE_CHANGED)
ret = btrfs_unlink_all_paths(sctx);
goto out;
}
}
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);
sctx->cur_inode_rdev = btrfs_inode_rdev(
sctx->left_path->nodes[0], left_ii);
if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID)
ret = send_create_inode_if_needed(sctx);
} 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) {
/*
* 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.
*/
if (sctx->cur_inode_new_gen) {
/*
* First, process the inode as if it was 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);
ret = process_all_refs(sctx,
BTRFS_COMPARE_TREE_DELETED);
if (ret < 0)
goto out;
/*
* Now process the inode as if it was 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);
sctx->cur_inode_rdev = btrfs_inode_rdev(
sctx->left_path->nodes[0], left_ii);
ret = send_create_inode_if_needed(sctx);
if (ret < 0)
goto out;
ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW);
if (ret < 0)
goto out;
/*
* 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;
/*
* Now process all extents and xattrs of the inode as if
* they were all new.
*/
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;
}
/*
* 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.
*/
static int changed_ref(struct send_ctx *sctx,
enum btrfs_compare_tree_result result)
{
int ret = 0;
if (sctx->cur_ino != sctx->cmp_key->objectid) {
inconsistent_snapshot_error(sctx, result, "reference");
return -EIO;
}
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;
}
/*
* 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
*/
static int changed_xattr(struct send_ctx *sctx,
enum btrfs_compare_tree_result result)
{
int ret = 0;
if (sctx->cur_ino != sctx->cmp_key->objectid) {
inconsistent_snapshot_error(sctx, result, "xattr");
return -EIO;
}
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;
}
/*
* 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
*/
static int changed_extent(struct send_ctx *sctx,
enum btrfs_compare_tree_result result)
{
int ret = 0;
/*
* We have found an extent item that changed without the inode item
* having changed. This can happen either after relocation (where the
* disk_bytenr of an extent item is replaced at
* relocation.c:replace_file_extents()) or after deduplication into a
* file in both the parent and send snapshots (where an extent item can
* get modified or replaced with a new one). Note that deduplication
* updates the inode item, but it only changes the iversion (sequence
* field in the inode item) of the inode, so if a file is deduplicated
* the same amount of times in both the parent and send snapshots, its
* iversion becomes the same in both snapshots, whence the inode item is
* the same on both snapshots.
*/
if (sctx->cur_ino != sctx->cmp_key->objectid)
return 0;
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;
}
static int dir_changed(struct send_ctx *sctx, u64 dir)
{
u64 orig_gen, new_gen;
int ret;
ret = get_inode_info(sctx->send_root, dir, NULL, &new_gen, NULL, NULL,
NULL, NULL);
if (ret)
return ret;
ret = get_inode_info(sctx->parent_root, dir, NULL, &orig_gen, NULL,
NULL, NULL, NULL);
if (ret)
return ret;
return (orig_gen != new_gen) ? 1 : 0;
}
static int compare_refs(struct send_ctx *sctx, struct btrfs_path *path,
struct btrfs_key *key)
{
struct btrfs_inode_extref *extref;
struct extent_buffer *leaf;
u64 dirid = 0, last_dirid = 0;
unsigned long ptr;
u32 item_size;
u32 cur_offset = 0;
int ref_name_len;
int ret = 0;
/* Easy case, just check this one dirid */
if (key->type == BTRFS_INODE_REF_KEY) {
dirid = key->offset;
ret = dir_changed(sctx, dirid);
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size(leaf, path->slots[0]);
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
while (cur_offset < item_size) {
extref = (struct btrfs_inode_extref *)(ptr +
cur_offset);
dirid = btrfs_inode_extref_parent(leaf, extref);
ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
cur_offset += ref_name_len + sizeof(*extref);
if (dirid == last_dirid)
continue;
ret = dir_changed(sctx, dirid);
if (ret)
break;
last_dirid = dirid;
}
out:
return ret;
}
/*
* Updates compare related fields in sctx and simply forwards to the actual
* changed_xxx functions.
*/
static int changed_cb(struct btrfs_path *left_path,
struct btrfs_path *right_path,
struct btrfs_key *key,
enum btrfs_compare_tree_result result,
struct send_ctx *sctx)
{
int ret = 0;
/*
* We can not hold the commit root semaphore here. This is because in
* the case of sending and receiving to the same filesystem, using a
* pipe, could result in a deadlock:
*
* 1) The task running send blocks on the pipe because it's full;
*
* 2) The task running receive, which is the only consumer of the pipe,
* is waiting for a transaction commit (for example due to a space
* reservation when doing a write or triggering a transaction commit
* when creating a subvolume);
*
* 3) The transaction is waiting to write lock the commit root semaphore,
* but can not acquire it since it's being held at 1).
*
* Down this call chain we write to the pipe through kernel_write().
* The same type of problem can also happen when sending to a file that
* is stored in the same filesystem - when reserving space for a write
* into the file, we can trigger a transaction commit.
*
* Our caller has supplied us with clones of leaves from the send and
* parent roots, so we're safe here from a concurrent relocation and
* further reallocation of metadata extents while we are here. Below we
* also assert that the leaves are clones.
*/
lockdep_assert_not_held(&sctx->send_root->fs_info->commit_root_sem);
/*
* We always have a send root, so left_path is never NULL. We will not
* have a leaf when we have reached the end of the send root but have
* not yet reached the end of the parent root.
*/
if (left_path->nodes[0])
ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED,
&left_path->nodes[0]->bflags));
/*
* When doing a full send we don't have a parent root, so right_path is
* NULL. When doing an incremental send, we may have reached the end of
* the parent root already, so we don't have a leaf at right_path.
*/
if (right_path && right_path->nodes[0])
ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED,
&right_path->nodes[0]->bflags));
if (result == BTRFS_COMPARE_TREE_SAME) {
if (key->type == BTRFS_INODE_REF_KEY ||
key->type == BTRFS_INODE_EXTREF_KEY) {
ret = compare_refs(sctx, left_path, key);
if (!ret)
return 0;
if (ret < 0)
return ret;
} else if (key->type == BTRFS_EXTENT_DATA_KEY) {
return maybe_send_hole(sctx, left_path, key);
} else {
return 0;
}
result = BTRFS_COMPARE_TREE_CHANGED;
ret = 0;
}
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;
/* Ignore non-FS objects */
if (key->objectid == BTRFS_FREE_INO_OBJECTID ||
key->objectid == BTRFS_FREE_SPACE_OBJECTID)
goto out;
if (key->type == BTRFS_INODE_ITEM_KEY) {
ret = changed_inode(sctx, result);
} else if (!sctx->ignore_cur_inode) {
if (key->type == BTRFS_INODE_REF_KEY ||
key->type == BTRFS_INODE_EXTREF_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 search_key_again(const struct send_ctx *sctx,
struct btrfs_root *root,
struct btrfs_path *path,
const struct btrfs_key *key)
{
int ret;
if (!path->need_commit_sem)
lockdep_assert_held_read(&root->fs_info->commit_root_sem);
/*
* Roots used for send operations are readonly and no one can add,
* update or remove keys from them, so we should be able to find our
* key again. The only exception is deduplication, which can operate on
* readonly roots and add, update or remove keys to/from them - but at
* the moment we don't allow it to run in parallel with send.
*/
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
ASSERT(ret <= 0);
if (ret > 0) {
btrfs_print_tree(path->nodes[path->lowest_level], false);
btrfs_err(root->fs_info,
"send: key (%llu %u %llu) not found in %s root %llu, lowest_level %d, slot %d",
key->objectid, key->type, key->offset,
(root == sctx->parent_root ? "parent" : "send"),
root->root_key.objectid, path->lowest_level,
path->slots[path->lowest_level]);
return -EUCLEAN;
}
return ret;
}
static int full_send_tree(struct send_ctx *sctx)
{
int ret;
struct btrfs_root *send_root = sctx->send_root;
struct btrfs_key key;
struct btrfs_fs_info *fs_info = send_root->fs_info;
struct btrfs_path *path;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD_ALWAYS;
key.objectid = BTRFS_FIRST_FREE_OBJECTID;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
down_read(&fs_info->commit_root_sem);
sctx->last_reloc_trans = fs_info->last_reloc_trans;
up_read(&fs_info->commit_root_sem);
ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret)
goto out_finish;
while (1) {
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
ret = changed_cb(path, NULL, &key,
BTRFS_COMPARE_TREE_NEW, sctx);
if (ret < 0)
goto out;
down_read(&fs_info->commit_root_sem);
if (fs_info->last_reloc_trans > sctx->last_reloc_trans) {
sctx->last_reloc_trans = fs_info->last_reloc_trans;
up_read(&fs_info->commit_root_sem);
/*
* A transaction used for relocating a block group was
* committed or is about to finish its commit. Release
* our path (leaf) and restart the search, so that we
* avoid operating on any file extent items that are
* stale, with a disk_bytenr that reflects a pre
* relocation value. This way we avoid as much as
* possible to fallback to regular writes when checking
* if we can clone file ranges.
*/
btrfs_release_path(path);
ret = search_key_again(sctx, send_root, path, &key);
if (ret < 0)
goto out;
} else {
up_read(&fs_info->commit_root_sem);
}
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);
return ret;
}
static int replace_node_with_clone(struct btrfs_path *path, int level)
{
struct extent_buffer *clone;
clone = btrfs_clone_extent_buffer(path->nodes[level]);
if (!clone)
return -ENOMEM;
free_extent_buffer(path->nodes[level]);
path->nodes[level] = clone;
return 0;
}
static int tree_move_down(struct btrfs_path *path, int *level, u64 reada_min_gen)
{
struct extent_buffer *eb;
struct extent_buffer *parent = path->nodes[*level];
int slot = path->slots[*level];
const int nritems = btrfs_header_nritems(parent);
u64 reada_max;
u64 reada_done = 0;
lockdep_assert_held_read(&parent->fs_info->commit_root_sem);
BUG_ON(*level == 0);
eb = btrfs_read_node_slot(parent, slot);
if (IS_ERR(eb))
return PTR_ERR(eb);
/*
* Trigger readahead for the next leaves we will process, so that it is
* very likely that when we need them they are already in memory and we
* will not block on disk IO. For nodes we only do readahead for one,
* since the time window between processing nodes is typically larger.
*/
reada_max = (*level == 1 ? SZ_128K : eb->fs_info->nodesize);
for (slot++; slot < nritems && reada_done < reada_max; slot++) {
if (btrfs_node_ptr_generation(parent, slot) > reada_min_gen) {
btrfs_readahead_node_child(parent, slot);
reada_done += eb->fs_info->nodesize;
}
}
path->nodes[*level - 1] = eb;
path->slots[*level - 1] = 0;
(*level)--;
if (*level == 0)
return replace_node_with_clone(path, 0);
return 0;
}
static int tree_move_next_or_upnext(struct btrfs_path *path,
int *level, int root_level)
{
int ret = 0;
int nritems;
nritems = btrfs_header_nritems(path->nodes[*level]);
path->slots[*level]++;
while (path->slots[*level] >= nritems) {
if (*level == root_level) {
path->slots[*level] = nritems - 1;
return -1;
}
/* move upnext */
path->slots[*level] = 0;
free_extent_buffer(path->nodes[*level]);
path->nodes[*level] = NULL;
(*level)++;
path->slots[*level]++;
nritems = btrfs_header_nritems(path->nodes[*level]);
ret = 1;
}
return ret;
}
/*
* Returns 1 if it had to move up and next. 0 is returned if it moved only next
* or down.
*/
static int tree_advance(struct btrfs_path *path,
int *level, int root_level,
int allow_down,
struct btrfs_key *key,
u64 reada_min_gen)
{
int ret;
if (*level == 0 || !allow_down) {
ret = tree_move_next_or_upnext(path, level, root_level);
} else {
ret = tree_move_down(path, level, reada_min_gen);
}
/*
* Even if we have reached the end of a tree, ret is -1, update the key
* anyway, so that in case we need to restart due to a block group
* relocation, we can assert that the last key of the root node still
* exists in the tree.
*/
if (*level == 0)
btrfs_item_key_to_cpu(path->nodes[*level], key,
path->slots[*level]);
else
btrfs_node_key_to_cpu(path->nodes[*level], key,
path->slots[*level]);
return ret;
}
static int tree_compare_item(struct btrfs_path *left_path,
struct btrfs_path *right_path,
char *tmp_buf)
{
int cmp;
int len1, len2;
unsigned long off1, off2;
len1 = btrfs_item_size(left_path->nodes[0], left_path->slots[0]);
len2 = btrfs_item_size(right_path->nodes[0], right_path->slots[0]);
if (len1 != len2)
return 1;
off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]);
off2 = btrfs_item_ptr_offset(right_path->nodes[0],
right_path->slots[0]);
read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1);
cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1);
if (cmp)
return 1;
return 0;
}
/*
* A transaction used for relocating a block group was committed or is about to
* finish its commit. Release our paths and restart the search, so that we are
* not using stale extent buffers:
*
* 1) For levels > 0, we are only holding references of extent buffers, without
* any locks on them, which does not prevent them from having been relocated
* and reallocated after the last time we released the commit root semaphore.
* The exception are the root nodes, for which we always have a clone, see
* the comment at btrfs_compare_trees();
*
* 2) For leaves, level 0, we are holding copies (clones) of extent buffers, so
* we are safe from the concurrent relocation and reallocation. However they
* can have file extent items with a pre relocation disk_bytenr value, so we
* restart the start from the current commit roots and clone the new leaves so
* that we get the post relocation disk_bytenr values. Not doing so, could
* make us clone the wrong data in case there are new extents using the old
* disk_bytenr that happen to be shared.
*/
static int restart_after_relocation(struct btrfs_path *left_path,
struct btrfs_path *right_path,
const struct btrfs_key *left_key,
const struct btrfs_key *right_key,
int left_level,
int right_level,
const struct send_ctx *sctx)
{
int root_level;
int ret;
lockdep_assert_held_read(&sctx->send_root->fs_info->commit_root_sem);
btrfs_release_path(left_path);
btrfs_release_path(right_path);
/*
* Since keys can not be added or removed to/from our roots because they
* are readonly and we do not allow deduplication to run in parallel
* (which can add, remove or change keys), the layout of the trees should
* not change.
*/
left_path->lowest_level = left_level;
ret = search_key_again(sctx, sctx->send_root, left_path, left_key);
if (ret < 0)
return ret;
right_path->lowest_level = right_level;
ret = search_key_again(sctx, sctx->parent_root, right_path, right_key);
if (ret < 0)
return ret;
/*
* If the lowest level nodes are leaves, clone them so that they can be
* safely used by changed_cb() while not under the protection of the
* commit root semaphore, even if relocation and reallocation happens in
* parallel.
*/
if (left_level == 0) {
ret = replace_node_with_clone(left_path, 0);
if (ret < 0)
return ret;
}
if (right_level == 0) {
ret = replace_node_with_clone(right_path, 0);
if (ret < 0)
return ret;
}
/*
* Now clone the root nodes (unless they happen to be the leaves we have
* already cloned). This is to protect against concurrent snapshotting of
* the send and parent roots (see the comment at btrfs_compare_trees()).
*/
root_level = btrfs_header_level(sctx->send_root->commit_root);
if (root_level > 0) {
ret = replace_node_with_clone(left_path, root_level);
if (ret < 0)
return ret;
}
root_level = btrfs_header_level(sctx->parent_root->commit_root);
if (root_level > 0) {
ret = replace_node_with_clone(right_path, root_level);
if (ret < 0)
return ret;
}
return 0;
}
/*
* This function compares two trees and calls the provided callback for
* every changed/new/deleted item it finds.
* If shared tree blocks are encountered, whole subtrees are skipped, making
* the compare pretty fast on snapshotted subvolumes.
*
* This currently works on commit roots only. As commit roots are read only,
* we don't do any locking. The commit roots are protected with transactions.
* Transactions are ended and rejoined when a commit is tried in between.
*
* This function checks for modifications done to the trees while comparing.
* If it detects a change, it aborts immediately.
*/
static int btrfs_compare_trees(struct btrfs_root *left_root,
struct btrfs_root *right_root, struct send_ctx *sctx)
{
struct btrfs_fs_info *fs_info = left_root->fs_info;
int ret;
int cmp;
struct btrfs_path *left_path = NULL;
struct btrfs_path *right_path = NULL;
struct btrfs_key left_key;
struct btrfs_key right_key;
char *tmp_buf = NULL;
int left_root_level;
int right_root_level;
int left_level;
int right_level;
int left_end_reached = 0;
int right_end_reached = 0;
int advance_left = 0;
int advance_right = 0;
u64 left_blockptr;
u64 right_blockptr;
u64 left_gen;
u64 right_gen;
u64 reada_min_gen;
left_path = btrfs_alloc_path();
if (!left_path) {
ret = -ENOMEM;
goto out;
}
right_path = btrfs_alloc_path();
if (!right_path) {
ret = -ENOMEM;
goto out;
}
tmp_buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
if (!tmp_buf) {
ret = -ENOMEM;
goto out;
}
left_path->search_commit_root = 1;
left_path->skip_locking = 1;
right_path->search_commit_root = 1;
right_path->skip_locking = 1;
/*
* Strategy: Go to the first items of both trees. Then do
*
* If both trees are at level 0
* Compare keys of current items
* If left < right treat left item as new, advance left tree
* and repeat
* If left > right treat right item as deleted, advance right tree
* and repeat
* If left == right do deep compare of items, treat as changed if
* needed, advance both trees and repeat
* If both trees are at the same level but not at level 0
* Compare keys of current nodes/leafs
* If left < right advance left tree and repeat
* If left > right advance right tree and repeat
* If left == right compare blockptrs of the next nodes/leafs
* If they match advance both trees but stay at the same level
* and repeat
* If they don't match advance both trees while allowing to go
* deeper and repeat
* If tree levels are different
* Advance the tree that needs it and repeat
*
* Advancing a tree means:
* If we are at level 0, try to go to the next slot. If that's not
* possible, go one level up and repeat. Stop when we found a level
* where we could go to the next slot. We may at this point be on a
* node or a leaf.
*
* If we are not at level 0 and not on shared tree blocks, go one
* level deeper.
*
* If we are not at level 0 and on shared tree blocks, go one slot to
* the right if possible or go up and right.
*/
down_read(&fs_info->commit_root_sem);
left_level = btrfs_header_level(left_root->commit_root);
left_root_level = left_level;
/*
* We clone the root node of the send and parent roots to prevent races
* with snapshot creation of these roots. Snapshot creation COWs the
* root node of a tree, so after the transaction is committed the old
* extent can be reallocated while this send operation is still ongoing.
* So we clone them, under the commit root semaphore, to be race free.
*/
left_path->nodes[left_level] =
btrfs_clone_extent_buffer(left_root->commit_root);
if (!left_path->nodes[left_level]) {
ret = -ENOMEM;
goto out_unlock;
}
right_level = btrfs_header_level(right_root->commit_root);
right_root_level = right_level;
right_path->nodes[right_level] =
btrfs_clone_extent_buffer(right_root->commit_root);
if (!right_path->nodes[right_level]) {
ret = -ENOMEM;
goto out_unlock;
}
/*
* Our right root is the parent root, while the left root is the "send"
* root. We know that all new nodes/leaves in the left root must have
* a generation greater than the right root's generation, so we trigger
* readahead for those nodes and leaves of the left root, as we know we
* will need to read them at some point.
*/
reada_min_gen = btrfs_header_generation(right_root->commit_root);
if (left_level == 0)
btrfs_item_key_to_cpu(left_path->nodes[left_level],
&left_key, left_path->slots[left_level]);
else
btrfs_node_key_to_cpu(left_path->nodes[left_level],
&left_key, left_path->slots[left_level]);
if (right_level == 0)
btrfs_item_key_to_cpu(right_path->nodes[right_level],
&right_key, right_path->slots[right_level]);
else
btrfs_node_key_to_cpu(right_path->nodes[right_level],
&right_key, right_path->slots[right_level]);
sctx->last_reloc_trans = fs_info->last_reloc_trans;
while (1) {
if (need_resched() ||
rwsem_is_contended(&fs_info->commit_root_sem)) {
up_read(&fs_info->commit_root_sem);
cond_resched();
down_read(&fs_info->commit_root_sem);
}
if (fs_info->last_reloc_trans > sctx->last_reloc_trans) {
ret = restart_after_relocation(left_path, right_path,
&left_key, &right_key,
left_level, right_level,
sctx);
if (ret < 0)
goto out_unlock;
sctx->last_reloc_trans = fs_info->last_reloc_trans;
}
if (advance_left && !left_end_reached) {
ret = tree_advance(left_path, &left_level,
left_root_level,
advance_left != ADVANCE_ONLY_NEXT,
&left_key, reada_min_gen);
if (ret == -1)
left_end_reached = ADVANCE;
else if (ret < 0)
goto out_unlock;
advance_left = 0;
}
if (advance_right && !right_end_reached) {
ret = tree_advance(right_path, &right_level,
right_root_level,
advance_right != ADVANCE_ONLY_NEXT,
&right_key, reada_min_gen);
if (ret == -1)
right_end_reached = ADVANCE;
else if (ret < 0)
goto out_unlock;
advance_right = 0;
}
if (left_end_reached && right_end_reached) {
ret = 0;
goto out_unlock;
} else if (left_end_reached) {
if (right_level == 0) {
up_read(&fs_info->commit_root_sem);
ret = changed_cb(left_path, right_path,
&right_key,
BTRFS_COMPARE_TREE_DELETED,
sctx);
if (ret < 0)
goto out;
down_read(&fs_info->commit_root_sem);
}
advance_right = ADVANCE;
continue;
} else if (right_end_reached) {
if (left_level == 0) {
up_read(&fs_info->commit_root_sem);
ret = changed_cb(left_path, right_path,
&left_key,
BTRFS_COMPARE_TREE_NEW,
sctx);
if (ret < 0)
goto out;
down_read(&fs_info->commit_root_sem);
}
advance_left = ADVANCE;
continue;
}
if (left_level == 0 && right_level == 0) {
up_read(&fs_info->commit_root_sem);
cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
if (cmp < 0) {
ret = changed_cb(left_path, right_path,
&left_key,
BTRFS_COMPARE_TREE_NEW,
sctx);
advance_left = ADVANCE;
} else if (cmp > 0) {
ret = changed_cb(left_path, right_path,
&right_key,
BTRFS_COMPARE_TREE_DELETED,
sctx);
advance_right = ADVANCE;
} else {
enum btrfs_compare_tree_result result;
WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
ret = tree_compare_item(left_path, right_path,
tmp_buf);
if (ret)
result = BTRFS_COMPARE_TREE_CHANGED;
else
result = BTRFS_COMPARE_TREE_SAME;
ret = changed_cb(left_path, right_path,
&left_key, result, sctx);
advance_left = ADVANCE;
advance_right = ADVANCE;
}
if (ret < 0)
goto out;
down_read(&fs_info->commit_root_sem);
} else if (left_level == right_level) {
cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
if (cmp < 0) {
advance_left = ADVANCE;
} else if (cmp > 0) {
advance_right = ADVANCE;
} else {
left_blockptr = btrfs_node_blockptr(
left_path->nodes[left_level],
left_path->slots[left_level]);
right_blockptr = btrfs_node_blockptr(
right_path->nodes[right_level],
right_path->slots[right_level]);
left_gen = btrfs_node_ptr_generation(
left_path->nodes[left_level],
left_path->slots[left_level]);
right_gen = btrfs_node_ptr_generation(
right_path->nodes[right_level],
right_path->slots[right_level]);
if (left_blockptr == right_blockptr &&
left_gen == right_gen) {
/*
* As we're on a shared block, don't
* allow to go deeper.
*/
advance_left = ADVANCE_ONLY_NEXT;
advance_right = ADVANCE_ONLY_NEXT;
} else {
advance_left = ADVANCE;
advance_right = ADVANCE;
}
}
} else if (left_level < right_level) {
advance_right = ADVANCE;
} else {
advance_left = ADVANCE;
}
}
out_unlock:
up_read(&fs_info->commit_root_sem);
out:
btrfs_free_path(left_path);
btrfs_free_path(right_path);
kvfree(tmp_buf);
return ret;
}
static int send_subvol(struct send_ctx *sctx)
{
int ret;
if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_STREAM_HEADER)) {
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, 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:
free_recorded_refs(sctx);
return ret;
}
/*
* If orphan cleanup did remove any orphans from a root, it means the tree
* was modified and therefore the commit root is not the same as the current
* root anymore. This is a problem, because send uses the commit root and
* therefore can see inode items that don't exist in the current root anymore,
* and for example make calls to btrfs_iget, which will do tree lookups based
* on the current root and not on the commit root. Those lookups will fail,
* returning a -ESTALE error, and making send fail with that error. So make
* sure a send does not see any orphans we have just removed, and that it will
* see the same inodes regardless of whether a transaction commit happened
* before it started (meaning that the commit root will be the same as the
* current root) or not.
*/
static int ensure_commit_roots_uptodate(struct send_ctx *sctx)
{
int i;
struct btrfs_trans_handle *trans = NULL;
again:
if (sctx->parent_root &&
sctx->parent_root->node != sctx->parent_root->commit_root)
goto commit_trans;
for (i = 0; i < sctx->clone_roots_cnt; i++)
if (sctx->clone_roots[i].root->node !=
sctx->clone_roots[i].root->commit_root)
goto commit_trans;
if (trans)
return btrfs_end_transaction(trans);
return 0;
commit_trans:
/* Use any root, all fs roots will get their commit roots updated. */
if (!trans) {
trans = btrfs_join_transaction(sctx->send_root);
if (IS_ERR(trans))
return PTR_ERR(trans);
goto again;
}
return btrfs_commit_transaction(trans);
}
/*
* Make sure any existing dellaloc is flushed for any root used by a send
* operation so that we do not miss any data and we do not race with writeback
* finishing and changing a tree while send is using the tree. This could
* happen if a subvolume is in RW mode, has delalloc, is turned to RO mode and
* a send operation then uses the subvolume.
* After flushing delalloc ensure_commit_roots_uptodate() must be called.
*/
static int flush_delalloc_roots(struct send_ctx *sctx)
{
struct btrfs_root *root = sctx->parent_root;
int ret;
int i;
if (root) {
ret = btrfs_start_delalloc_snapshot(root, false);
if (ret)
return ret;
btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX);
}
for (i = 0; i < sctx->clone_roots_cnt; i++) {
root = sctx->clone_roots[i].root;
ret = btrfs_start_delalloc_snapshot(root, false);
if (ret)
return ret;
btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX);
}
return 0;
}
static void btrfs_root_dec_send_in_progress(struct btrfs_root* root)
{
spin_lock(&root->root_item_lock);
root->send_in_progress--;
/*
* Not much left to do, we don't know why it's unbalanced and
* can't blindly reset it to 0.
*/
if (root->send_in_progress < 0)
btrfs_err(root->fs_info,
"send_in_progress unbalanced %d root %llu",
root->send_in_progress, root->root_key.objectid);
spin_unlock(&root->root_item_lock);
}
static void dedupe_in_progress_warn(const struct btrfs_root *root)
{
btrfs_warn_rl(root->fs_info,
"cannot use root %llu for send while deduplications on it are in progress (%d in progress)",
root->root_key.objectid, root->dedupe_in_progress);
}
long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
{
int ret = 0;
struct btrfs_root *send_root = BTRFS_I(file_inode(mnt_file))->root;
struct btrfs_fs_info *fs_info = send_root->fs_info;
struct btrfs_root *clone_root;
struct send_ctx *sctx = NULL;
u32 i;
u64 *clone_sources_tmp = NULL;
int clone_sources_to_rollback = 0;
size_t alloc_size;
int sort_clone_roots = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/*
* The subvolume must remain read-only during send, protect against
* making it RW. This also protects against deletion.
*/
spin_lock(&send_root->root_item_lock);
if (btrfs_root_readonly(send_root) && send_root->dedupe_in_progress) {
dedupe_in_progress_warn(send_root);
spin_unlock(&send_root->root_item_lock);
return -EAGAIN;
}
send_root->send_in_progress++;
spin_unlock(&send_root->root_item_lock);
/*
* Userspace tools do the checks and warn the user if it's
* not RO.
*/
if (!btrfs_root_readonly(send_root)) {
ret = -EPERM;
goto out;
}
/*
* Check that we don't overflow at later allocations, we request
* clone_sources_count + 1 items, and compare to unsigned long inside
* access_ok.
*/
if (arg->clone_sources_count >
ULONG_MAX / sizeof(struct clone_root) - 1) {
ret = -EINVAL;
goto out;
}
if (arg->flags & ~BTRFS_SEND_FLAG_MASK) {
ret = -EINVAL;
goto out;
}
sctx = kzalloc(sizeof(struct send_ctx), GFP_KERNEL);
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_KERNEL);
INIT_LIST_HEAD(&sctx->name_cache_list);
sctx->flags = arg->flags;
if (arg->flags & BTRFS_SEND_FLAG_VERSION) {
if (arg->version > BTRFS_SEND_STREAM_VERSION) {
ret = -EPROTO;
goto out;
}
/* Zero means "use the highest version" */
sctx->proto = arg->version ?: BTRFS_SEND_STREAM_VERSION;
} else {
sctx->proto = 1;
}
sctx->send_filp = fget(arg->send_fd);
if (!sctx->send_filp) {
ret = -EBADF;
goto out;
}
sctx->send_root = send_root;
/*
* Unlikely but possible, if the subvolume is marked for deletion but
* is slow to remove the directory entry, send can still be started
*/
if (btrfs_root_dead(sctx->send_root)) {
ret = -EPERM;
goto out;
}
sctx->clone_roots_cnt = arg->clone_sources_count;
sctx->send_max_size = BTRFS_SEND_BUF_SIZE;
sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL);
if (!sctx->send_buf) {
ret = -ENOMEM;
goto out;
}
sctx->pending_dir_moves = RB_ROOT;
sctx->waiting_dir_moves = RB_ROOT;
sctx->orphan_dirs = RB_ROOT;
sctx->clone_roots = kvcalloc(sizeof(*sctx->clone_roots),
arg->clone_sources_count + 1,
GFP_KERNEL);
if (!sctx->clone_roots) {
ret = -ENOMEM;
goto out;
}
alloc_size = array_size(sizeof(*arg->clone_sources),
arg->clone_sources_count);
if (arg->clone_sources_count) {
clone_sources_tmp = kvmalloc(alloc_size, GFP_KERNEL);
if (!clone_sources_tmp) {
ret = -ENOMEM;
goto out;
}
ret = copy_from_user(clone_sources_tmp, arg->clone_sources,
alloc_size);
if (ret) {
ret = -EFAULT;
goto out;
}
for (i = 0; i < arg->clone_sources_count; i++) {
clone_root = btrfs_get_fs_root(fs_info,
clone_sources_tmp[i], true);
if (IS_ERR(clone_root)) {
ret = PTR_ERR(clone_root);
goto out;
}
spin_lock(&clone_root->root_item_lock);
if (!btrfs_root_readonly(clone_root) ||
btrfs_root_dead(clone_root)) {
spin_unlock(&clone_root->root_item_lock);
btrfs_put_root(clone_root);
ret = -EPERM;
goto out;
}
if (clone_root->dedupe_in_progress) {
dedupe_in_progress_warn(clone_root);
spin_unlock(&clone_root->root_item_lock);
btrfs_put_root(clone_root);
ret = -EAGAIN;
goto out;
}
clone_root->send_in_progress++;
spin_unlock(&clone_root->root_item_lock);
sctx->clone_roots[i].root = clone_root;
clone_sources_to_rollback = i + 1;
}
kvfree(clone_sources_tmp);
clone_sources_tmp = NULL;
}
if (arg->parent_root) {
sctx->parent_root = btrfs_get_fs_root(fs_info, arg->parent_root,
true);
if (IS_ERR(sctx->parent_root)) {
ret = PTR_ERR(sctx->parent_root);
goto out;
}
spin_lock(&sctx->parent_root->root_item_lock);
sctx->parent_root->send_in_progress++;
if (!btrfs_root_readonly(sctx->parent_root) ||
btrfs_root_dead(sctx->parent_root)) {
spin_unlock(&sctx->parent_root->root_item_lock);
ret = -EPERM;
goto out;
}
if (sctx->parent_root->dedupe_in_progress) {
dedupe_in_progress_warn(sctx->parent_root);
spin_unlock(&sctx->parent_root->root_item_lock);
ret = -EAGAIN;
goto out;
}
spin_unlock(&sctx->parent_root->root_item_lock);
}
/*
* 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 =
btrfs_grab_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);
sort_clone_roots = 1;
ret = flush_delalloc_roots(sctx);
if (ret)
goto out;
ret = ensure_commit_roots_uptodate(sctx);
if (ret)
goto out;
ret = send_subvol(sctx);
if (ret < 0)
goto out;
if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_END_CMD)) {
ret = begin_cmd(sctx, BTRFS_SEND_C_END);
if (ret < 0)
goto out;
ret = send_cmd(sctx);
if (ret < 0)
goto out;
}
out:
WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->pending_dir_moves));
while (sctx && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)) {
struct rb_node *n;
struct pending_dir_move *pm;
n = rb_first(&sctx->pending_dir_moves);
pm = rb_entry(n, struct pending_dir_move, node);
while (!list_empty(&pm->list)) {
struct pending_dir_move *pm2;
pm2 = list_first_entry(&pm->list,
struct pending_dir_move, list);
free_pending_move(sctx, pm2);
}
free_pending_move(sctx, pm);
}
WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves));
while (sctx && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) {
struct rb_node *n;
struct waiting_dir_move *dm;
n = rb_first(&sctx->waiting_dir_moves);
dm = rb_entry(n, struct waiting_dir_move, node);
rb_erase(&dm->node, &sctx->waiting_dir_moves);
kfree(dm);
}
WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->orphan_dirs));
while (sctx && !RB_EMPTY_ROOT(&sctx->orphan_dirs)) {
struct rb_node *n;
struct orphan_dir_info *odi;
n = rb_first(&sctx->orphan_dirs);
odi = rb_entry(n, struct orphan_dir_info, node);
free_orphan_dir_info(sctx, odi);
}
if (sort_clone_roots) {
for (i = 0; i < sctx->clone_roots_cnt; i++) {
btrfs_root_dec_send_in_progress(
sctx->clone_roots[i].root);
btrfs_put_root(sctx->clone_roots[i].root);
}
} else {
for (i = 0; sctx && i < clone_sources_to_rollback; i++) {
btrfs_root_dec_send_in_progress(
sctx->clone_roots[i].root);
btrfs_put_root(sctx->clone_roots[i].root);
}
btrfs_root_dec_send_in_progress(send_root);
}
if (sctx && !IS_ERR_OR_NULL(sctx->parent_root)) {
btrfs_root_dec_send_in_progress(sctx->parent_root);
btrfs_put_root(sctx->parent_root);
}
kvfree(clone_sources_tmp);
if (sctx) {
if (sctx->send_filp)
fput(sctx->send_filp);
kvfree(sctx->clone_roots);
kvfree(sctx->send_buf);
name_cache_free(sctx);
kfree(sctx);
}
return ret;
}