blob: fb3675f5bf50204f3b432cc686786518cb0c0515 [file] [log] [blame]
// 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 <linux/fsverity.h>
#include "send.h"
#include "ctree.h"
#include "backref.h"
#include "locking.h"
#include "disk-io.h"
#include "btrfs_inode.h"
#include "transaction.h"
#include "compression.h"
#include "print-tree.h"
#include "accessors.h"
#include "dir-item.h"
#include "file-item.h"
#include "ioctl.h"
#include "verity.h"
#include "lru_cache.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 1024
/*
* 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 num_bytes;
bool found_ref;
};
#define SEND_MAX_NAME_CACHE_SIZE 256
/*
* Limit the root_ids array of struct backref_cache_entry to 17 elements.
* This makes the size of a cache entry to be exactly 192 bytes on x86_64, which
* can be satisfied from the kmalloc-192 slab, without wasting any space.
* The most common case is to have a single root for cloning, which corresponds
* to the send root. Having the user specify more than 16 clone roots is not
* common, and in such rare cases we simply don't use caching if the number of
* cloning roots that lead down to a leaf is more than 17.
*/
#define SEND_MAX_BACKREF_CACHE_ROOTS 17
/*
* Max number of entries in the cache.
* With SEND_MAX_BACKREF_CACHE_ROOTS as 17, the size in bytes, excluding
* maple tree's internal nodes, is 24K.
*/
#define SEND_MAX_BACKREF_CACHE_SIZE 128
/*
* A backref cache entry maps a leaf to a list of IDs of roots from which the
* leaf is accessible and we can use for clone operations.
* With SEND_MAX_BACKREF_CACHE_ROOTS as 12, each cache entry is 128 bytes (on
* x86_64).
*/
struct backref_cache_entry {
struct btrfs_lru_cache_entry entry;
u64 root_ids[SEND_MAX_BACKREF_CACHE_ROOTS];
/* Number of valid elements in the root_ids array. */
int num_roots;
};
/* See the comment at lru_cache.h about struct btrfs_lru_cache_entry. */
static_assert(offsetof(struct backref_cache_entry, entry) == 0);
/*
* Max number of entries in the cache that stores directories that were already
* created. The cache uses raw struct btrfs_lru_cache_entry entries, so it uses
* at most 4096 bytes - sizeof(struct btrfs_lru_cache_entry) is 48 bytes, but
* the kmalloc-64 slab is used, so we get 4096 bytes (64 bytes * 64).
*/
#define SEND_MAX_DIR_CREATED_CACHE_SIZE 64
/*
* Max number of entries in the cache that stores directories that were already
* created. The cache uses raw struct btrfs_lru_cache_entry entries, so it uses
* at most 4096 bytes - sizeof(struct btrfs_lru_cache_entry) is 48 bytes, but
* the kmalloc-64 slab is used, so we get 4096 bytes (64 bytes * 64).
*/
#define SEND_MAX_DIR_UTIMES_CACHE_SIZE 64
struct send_ctx {
struct file *send_filp;
loff_t send_off;
char *send_buf;
u32 send_size;
u32 send_max_size;
/*
* Whether BTRFS_SEND_A_DATA attribute was already added to current
* command (since protocol v2, data must be the last attribute).
*/
bool put_data;
struct page **send_buf_pages;
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;
u64 cur_inode_size;
u64 cur_inode_mode;
u64 cur_inode_rdev;
u64 cur_inode_last_extent;
u64 cur_inode_next_write_offset;
bool cur_inode_new;
bool cur_inode_new_gen;
bool cur_inode_deleted;
bool ignore_cur_inode;
bool cur_inode_needs_verity;
void *verity_descriptor;
u64 send_progress;
struct list_head new_refs;
struct list_head deleted_refs;
struct btrfs_lru_cache name_cache;
/*
* The inode we are currently processing. It's not NULL only when we
* need to issue write commands for data extents from this inode.
*/
struct inode *cur_inode;
struct file_ra_state ra;
u64 page_cache_clear_start;
bool clean_page_cache;
/*
* 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 rb_root rbtree_new_refs;
struct rb_root rbtree_deleted_refs;
struct btrfs_lru_cache backref_cache;
u64 backref_cache_last_reloc_trans;
struct btrfs_lru_cache dir_created_cache;
struct btrfs_lru_cache dir_utimes_cache;
};
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;
u64 dir_high_seq_ino;
};
struct name_cache_entry {
/*
* The key in the entry is an inode number, and the generation matches
* the inode's generation.
*/
struct btrfs_lru_cache_entry entry;
u64 parent_ino;
u64 parent_gen;
int ret;
int need_later_update;
int name_len;
char name[];
};
/* See the comment at lru_cache.h about struct btrfs_lru_cache_entry. */
static_assert(offsetof(struct name_cache_entry, entry) == 0);
#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,
btrfs_root_id(sctx->send_root),
(sctx->parent_root ? btrfs_root_id(sctx->parent_root) : 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;
case 3: return cmd <= BTRFS_SEND_C_MAX_V3;
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;
/*
* Allocate to the next largest kmalloc bucket size, to let
* the fast path happen most of the time.
*/
len = kmalloc_size_roundup(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;
p->buf_len = len;
if (p->reversed) {
tmp_buf = p->buf + old_buf_len - path_len - 1;
p->end = p->buf + p->buf_len - 1;
p->start = p->end - path_len;
memmove(p->start, tmp_buf, path_len + 1);
} else {
p->start = p->buf;
p->end = p->start + path_len;
}
return 0;
}
static int fs_path_prepare_for_add(struct fs_path *p, int name_len,
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)
{
p->reversed = from->reversed;
fs_path_reset(p);
return fs_path_add_path(p, from);
}
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);
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 (WARN_ON_ONCE(sctx->put_data))
return -EINVAL;
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(8)
TLV_PUT_DEFINE_INT(32)
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(sctx->proto);
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;
if (unlikely(sctx->send_size != 0)) {
btrfs_err(sctx->send_root->fs_info,
"send: command header buffer not empty cmd %d offset %llu",
cmd, sctx->send_off);
return -EINVAL;
}
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 = 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->send_size = 0;
sctx->put_data = false;
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;
}
struct btrfs_inode_info {
u64 size;
u64 gen;
u64 mode;
u64 uid;
u64 gid;
u64 rdev;
u64 fileattr;
u64 nlink;
};
/*
* Helper function to retrieve some fields from an inode item.
*/
static int get_inode_info(struct btrfs_root *root, u64 ino,
struct btrfs_inode_info *info)
{
int ret;
struct btrfs_path *path;
struct btrfs_inode_item *ii;
struct btrfs_key key;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret) {
if (ret > 0)
ret = -ENOENT;
goto out;
}
if (!info)
goto out;
ii = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
info->size = btrfs_inode_size(path->nodes[0], ii);
info->gen = btrfs_inode_generation(path->nodes[0], ii);
info->mode = btrfs_inode_mode(path->nodes[0], ii);
info->uid = btrfs_inode_uid(path->nodes[0], ii);
info->gid = btrfs_inode_gid(path->nodes[0], ii);
info->rdev = btrfs_inode_rdev(path->nodes[0], ii);
info->nlink = btrfs_inode_nlink(path->nodes[0], ii);
/*
* Transfer the unchanged u64 value of btrfs_inode_item::flags, that's
* otherwise logically split to 32/32 parts.
*/
info->fileattr = btrfs_inode_flags(path->nodes[0], ii);
out:
btrfs_free_path(path);
return ret;
}
static int get_inode_gen(struct btrfs_root *root, u64 ino, u64 *gen)
{
int ret;
struct btrfs_inode_info info = { 0 };
ASSERT(gen);
ret = get_inode_info(root, ino, &info);
*gen = info.gen;
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;
}
if (unlikely(start < p->buf)) {
btrfs_err(root->fs_info,
"send: path ref buffer underflow for key (%llu %u %llu)",
found_key->objectid,
found_key->type,
found_key->offset);
ret = -EINVAL;
goto out;
}
}
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_ftype(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;
/* The bytenr the file extent item we are processing refers to. */
u64 bytenr;
/* The owner (root id) of the data backref for the current extent. */
u64 backref_owner;
/* The offset of the data backref for the current extent. */
u64 backref_offset;
};
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 < btrfs_root_id(cr->root))
return -1;
if (root > btrfs_root_id(cr->root))
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 (btrfs_root_id(cr1->root) < btrfs_root_id(cr2->root))
return -1;
if (btrfs_root_id(cr1->root) > btrfs_root_id(cr2->root))
return 1;
return 0;
}
/*
* Called for every backref that is found for the current extent.
* Results are collected in sctx->clone_roots->ino/offset.
*/
static int iterate_backrefs(u64 ino, u64 offset, u64 num_bytes, u64 root_id,
void *ctx_)
{
struct backref_ctx *bctx = ctx_;
struct clone_root *clone_root;
/* First check if the root is in the list of accepted clone sources */
clone_root = bsearch((void *)(uintptr_t)root_id, bctx->sctx->clone_roots,
bctx->sctx->clone_roots_cnt,
sizeof(struct clone_root),
__clone_root_cmp_bsearch);
if (!clone_root)
return 0;
/* This is our own reference, bail out as we can't clone from it. */
if (clone_root->root == bctx->sctx->send_root &&
ino == bctx->cur_objectid &&
offset == bctx->cur_offset)
return 0;
/*
* Make sure we don't consider clones from send_root that are
* behind the current inode/offset.
*/
if (clone_root->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++;
clone_root->found_ref = true;
/*
* If the given backref refers to a file extent item with a larger
* number of bytes than what we found before, use the new one so that
* we clone more optimally and end up doing less writes and getting
* less exclusive, non-shared extents at the destination.
*/
if (num_bytes > clone_root->num_bytes) {
clone_root->ino = ino;
clone_root->offset = offset;
clone_root->num_bytes = num_bytes;
/*
* Found a perfect candidate, so there's no need to continue
* backref walking.
*/
if (num_bytes >= bctx->extent_len)
return BTRFS_ITERATE_EXTENT_INODES_STOP;
}
return 0;
}
static bool lookup_backref_cache(u64 leaf_bytenr, void *ctx,
const u64 **root_ids_ret, int *root_count_ret)
{
struct backref_ctx *bctx = ctx;
struct send_ctx *sctx = bctx->sctx;
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
const u64 key = leaf_bytenr >> fs_info->sectorsize_bits;
struct btrfs_lru_cache_entry *raw_entry;
struct backref_cache_entry *entry;
if (sctx->backref_cache.size == 0)
return false;
/*
* If relocation happened since we first filled the cache, then we must
* empty the cache and can not use it, because even though we operate on
* read-only roots, their leaves and nodes may have been reallocated and
* now be used for different nodes/leaves of the same tree or some other
* tree.
*
* We are called from iterate_extent_inodes() while either holding a
* transaction handle or holding fs_info->commit_root_sem, so no need
* to take any lock here.
*/
if (fs_info->last_reloc_trans > sctx->backref_cache_last_reloc_trans) {
btrfs_lru_cache_clear(&sctx->backref_cache);
return false;
}
raw_entry = btrfs_lru_cache_lookup(&sctx->backref_cache, key, 0);
if (!raw_entry)
return false;
entry = container_of(raw_entry, struct backref_cache_entry, entry);
*root_ids_ret = entry->root_ids;
*root_count_ret = entry->num_roots;
return true;
}
static void store_backref_cache(u64 leaf_bytenr, const struct ulist *root_ids,
void *ctx)
{
struct backref_ctx *bctx = ctx;
struct send_ctx *sctx = bctx->sctx;
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
struct backref_cache_entry *new_entry;
struct ulist_iterator uiter;
struct ulist_node *node;
int ret;
/*
* We're called while holding a transaction handle or while holding
* fs_info->commit_root_sem (at iterate_extent_inodes()), so must do a
* NOFS allocation.
*/
new_entry = kmalloc(sizeof(struct backref_cache_entry), GFP_NOFS);
/* No worries, cache is optional. */
if (!new_entry)
return;
new_entry->entry.key = leaf_bytenr >> fs_info->sectorsize_bits;
new_entry->entry.gen = 0;
new_entry->num_roots = 0;
ULIST_ITER_INIT(&uiter);
while ((node = ulist_next(root_ids, &uiter)) != NULL) {
const u64 root_id = node->val;
struct clone_root *root;
root = bsearch((void *)(uintptr_t)root_id, sctx->clone_roots,
sctx->clone_roots_cnt, sizeof(struct clone_root),
__clone_root_cmp_bsearch);
if (!root)
continue;
/* Too many roots, just exit, no worries as caching is optional. */
if (new_entry->num_roots >= SEND_MAX_BACKREF_CACHE_ROOTS) {
kfree(new_entry);
return;
}
new_entry->root_ids[new_entry->num_roots] = root_id;
new_entry->num_roots++;
}
/*
* We may have not added any roots to the new cache entry, which means
* none of the roots is part of the list of roots from which we are
* allowed to clone. Cache the new entry as it's still useful to avoid
* backref walking to determine which roots have a path to the leaf.
*
* Also use GFP_NOFS because we're called while holding a transaction
* handle or while holding fs_info->commit_root_sem.
*/
ret = btrfs_lru_cache_store(&sctx->backref_cache, &new_entry->entry,
GFP_NOFS);
ASSERT(ret == 0 || ret == -ENOMEM);
if (ret) {
/* Caching is optional, no worries. */
kfree(new_entry);
return;
}
/*
* We are called from iterate_extent_inodes() while either holding a
* transaction handle or holding fs_info->commit_root_sem, so no need
* to take any lock here.
*/
if (sctx->backref_cache.size == 1)
sctx->backref_cache_last_reloc_trans = fs_info->last_reloc_trans;
}
static int check_extent_item(u64 bytenr, const struct btrfs_extent_item *ei,
const struct extent_buffer *leaf, void *ctx)
{
const u64 refs = btrfs_extent_refs(leaf, ei);
const struct backref_ctx *bctx = ctx;
const struct send_ctx *sctx = bctx->sctx;
if (bytenr == bctx->bytenr) {
const u64 flags = btrfs_extent_flags(leaf, ei);
if (WARN_ON(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
return -EUCLEAN;
/*
* If we have only one reference and only the send root as a
* clone source - meaning no clone roots were given in the
* struct btrfs_ioctl_send_args passed to the send ioctl - then
* it's our reference and there's no point in doing backref
* walking which is expensive, so exit early.
*/
if (refs == 1 && sctx->clone_roots_cnt == 1)
return -ENOENT;
}
/*
* 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 (refs > SEND_MAX_EXTENT_REFS)
return -ENOENT;
return 0;
}
static bool skip_self_data_ref(u64 root, u64 ino, u64 offset, void *ctx)
{
const struct backref_ctx *bctx = ctx;
if (ino == bctx->cur_objectid &&
root == bctx->backref_owner &&
offset == bctx->backref_offset)
return true;
return false;
}
/*
* 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;
struct btrfs_file_extent_item *fi;
struct extent_buffer *eb = path->nodes[0];
struct backref_ctx backref_ctx = { 0 };
struct btrfs_backref_walk_ctx backref_walk_ctx = { 0 };
struct clone_root *cur_clone_root;
int compressed;
u32 i;
/*
* With fallocate we can get prealloc extents beyond the inode's i_size,
* so we don't do anything here because clone operations can not clone
* to a range beyond i_size without increasing the i_size of the
* destination inode.
*/
if (data_offset >= ino_size)
return 0;
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)
return -ENOENT;
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
if (disk_byte == 0)
return -ENOENT;
compressed = btrfs_file_extent_compression(eb, fi);
num_bytes = btrfs_file_extent_num_bytes(eb, fi);
logical = disk_byte + btrfs_file_extent_offset(eb, fi);
/*
* 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->num_bytes = 0;
cur_clone_root->found_ref = false;
}
backref_ctx.sctx = sctx;
backref_ctx.cur_objectid = ino;
backref_ctx.cur_offset = data_offset;
backref_ctx.bytenr = disk_byte;
/*
* Use the header owner and not the send root's id, because in case of a
* snapshot we can have shared subtrees.
*/
backref_ctx.backref_owner = btrfs_header_owner(eb);
backref_ctx.backref_offset = data_offset - btrfs_file_extent_offset(eb, fi);
/*
* 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;
else
backref_ctx.extent_len = num_bytes;
/*
* Now collect all backrefs.
*/
backref_walk_ctx.bytenr = disk_byte;
if (compressed == BTRFS_COMPRESS_NONE)
backref_walk_ctx.extent_item_pos = btrfs_file_extent_offset(eb, fi);
backref_walk_ctx.fs_info = fs_info;
backref_walk_ctx.cache_lookup = lookup_backref_cache;
backref_walk_ctx.cache_store = store_backref_cache;
backref_walk_ctx.indirect_ref_iterator = iterate_backrefs;
backref_walk_ctx.check_extent_item = check_extent_item;
backref_walk_ctx.user_ctx = &backref_ctx;
/*
* If have a single clone root, then it's the send root and we can tell
* the backref walking code to skip our own backref and not resolve it,
* since we can not use it for cloning - the source and destination
* ranges can't overlap and in case the leaf is shared through a subtree
* due to snapshots, we can't use those other roots since they are not
* in the list of clone roots.
*/
if (sctx->clone_roots_cnt == 1)
backref_walk_ctx.skip_data_ref = skip_self_data_ref;
ret = iterate_extent_inodes(&backref_walk_ctx, true, iterate_backrefs,
&backref_ctx);
if (ret < 0)
return ret;
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);
return -ENOENT;
}
up_read(&fs_info->commit_root_sem);
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");
return -ENOENT;
}
cur_clone_root = NULL;
for (i = 0; i < sctx->clone_roots_cnt; i++) {
struct clone_root *clone_root = &sctx->clone_roots[i];
if (!clone_root->found_ref)
continue;
/*
* Choose the root from which we can clone more bytes, to
* minimize write operations and therefore have more extent
* sharing at the destination (the same as in the source).
*/
if (!cur_clone_root ||
clone_root->num_bytes > cur_clone_root->num_bytes) {
cur_clone_root = clone_root;
/*
* We found an optimal clone candidate (any inode from
* any root is fine), so we're done.
*/
if (clone_root->num_bytes >= backref_ctx.extent_len)
break;
}
}
if (cur_clone_root) {
*found = cur_clone_root;
ret = 0;
} else {
ret = -ENOENT;
}
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, btrfs_root_id(root));
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);
if (unlikely(type != BTRFS_FILE_EXTENT_INLINE)) {
ret = -EUCLEAN;
btrfs_crit(root->fs_info,
"send: found symlink extent that is not inline, ino %llu root %llu extent type %d",
ino, btrfs_root_id(root), type);
goto out;
}
compression = btrfs_file_extent_compression(path->nodes[0], ei);
if (unlikely(compression != BTRFS_COMPRESS_NONE)) {
ret = -EUCLEAN;
btrfs_crit(root->fs_info,
"send: found symlink extent with compression, ino %llu root %llu compression type %d",
ino, btrfs_root_id(root), compression);
goto out;
}
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) {
struct fscrypt_str tmp_name;
len = snprintf(tmp, sizeof(tmp), "o%llu-%llu-%llu",
ino, gen, idx);
ASSERT(len < sizeof(tmp));
tmp_name.name = tmp;
tmp_name.len = strlen(tmp);
di = btrfs_lookup_dir_item(NULL, sctx->send_root,
path, BTRFS_FIRST_FREE_OBJECTID,
&tmp_name, 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_name, 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,
u64 *send_gen, u64 *parent_gen)
{
int ret;
int left_ret;
int right_ret;
u64 left_gen;
u64 right_gen = 0;
struct btrfs_inode_info info;
ret = get_inode_info(sctx->send_root, ino, &info);
if (ret < 0 && ret != -ENOENT)
goto out;
left_ret = (info.nlink == 0) ? -ENOENT : ret;
left_gen = info.gen;
if (send_gen)
*send_gen = ((left_ret == -ENOENT) ? 0 : info.gen);
if (!sctx->parent_root) {
right_ret = -ENOENT;
} else {
ret = get_inode_info(sctx->parent_root, ino, &info);
if (ret < 0 && ret != -ENOENT)
goto out;
right_ret = (info.nlink == 0) ? -ENOENT : ret;
right_gen = info.gen;
if (parent_gen)
*parent_gen = ((right_ret == -ENOENT) ? 0 : info.gen);
}
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,
u64 *send_gen, u64 *parent_gen)
{
int ret;
if (ino == BTRFS_FIRST_FREE_OBJECTID)
return 1;
ret = get_cur_inode_state(sctx, ino, gen, send_gen, parent_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;
struct fscrypt_str name_str = FSTR_INIT((char *)name, name_len);
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
di = btrfs_lookup_dir_item(NULL, root, path, dir, &name_str, 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_gen(root, parent_dir, dir_gen);
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;
u64 parent_root_dir_gen;
u64 other_inode = 0;
struct btrfs_inode_info info;
if (!sctx->parent_root)
return 0;
ret = is_inode_existent(sctx, dir, dir_gen, NULL, &parent_root_dir_gen);
if (ret <= 0)
return 0;
/*
* 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.
*
* @parent_root_dir_gen was set to 0 if the inode does not exist in the
* parent root.
*/
if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID &&
parent_root_dir_gen != dir_gen)
return 0;
ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
&other_inode);
if (ret == -ENOENT)
return 0;
else if (ret < 0)
return ret;
/*
* 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, &info);
if (ret < 0)
return ret;
*who_ino = other_inode;
*who_gen = info.gen;
*who_mode = info.mode;
return 1;
}
return 0;
}
/*
* 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;
u64 ow_inode;
u64 ow_gen = 0;
u64 send_root_dir_gen;
if (!sctx->parent_root)
return 0;
ret = is_inode_existent(sctx, dir, dir_gen, &send_root_dir_gen, NULL);
if (ret <= 0)
return ret;
/*
* @send_root_dir_gen was set to 0 if the inode does not exist in the
* send root.
*/
if (dir != BTRFS_FIRST_FREE_OBJECTID && send_root_dir_gen != dir_gen)
return 0;
/* 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 == -ENOENT) {
/* was never and will never be overwritten */
return 0;
} else if (ret < 0) {
return ret;
}
if (ow_inode == ino) {
ret = get_inode_gen(sctx->send_root, ow_inode, &ow_gen);
if (ret < 0)
return ret;
/* It's the same inode, so no overwrite happened. */
if (ow_gen == ino_gen)
return 0;
}
/*
* 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)
return 1;
if (ino != sctx->cur_ino && ow_inode == sctx->cur_ino) {
if (ow_gen == 0) {
ret = get_inode_gen(sctx->send_root, ow_inode, &ow_gen);
if (ret < 0)
return ret;
}
if (ow_gen == sctx->cur_inode_gen)
return 1;
}
return 0;
}
/*
* 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;
}
static inline struct name_cache_entry *name_cache_search(struct send_ctx *sctx,
u64 ino, u64 gen)
{
struct btrfs_lru_cache_entry *entry;
entry = btrfs_lru_cache_lookup(&sctx->name_cache, ino, gen);
if (!entry)
return NULL;
return container_of(entry, struct name_cache_entry, entry);
}
/*
* 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;
/*
* 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) {
btrfs_lru_cache_remove(&sctx->name_cache, &nce->entry);
nce = NULL;
} else {
*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_if_needed().
*/
ret = is_inode_existent(sctx, ino, gen, NULL, NULL);
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->entry.key = ino;
nce->entry.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 = btrfs_lru_cache_store(&sctx->name_cache, &nce->entry, GFP_KERNEL);
if (nce_ret < 0) {
kfree(nce);
ret = nce_ret;
}
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 = btrfs_root_id(send_root);
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 != btrfs_root_id(send_root)) {
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_fileattr(struct send_ctx *sctx, u64 ino, u64 gen, u64 fileattr)
{
struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
int ret = 0;
struct fs_path *p;
if (sctx->proto < 2)
return 0;
btrfs_debug(fs_info, "send_fileattr %llu fileattr=%llu", ino, fileattr);
p = fs_path_alloc();
if (!p)
return -ENOMEM;
ret = begin_cmd(sctx, BTRFS_SEND_C_FILEATTR);
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_FILEATTR, fileattr);
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);
if (sctx->proto >= 2)
TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_OTIME, eb, &ii->otime);
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(p);
btrfs_free_path(path);
return ret;
}
/*
* If the cache is full, we can't remove entries from it and do a call to
* send_utimes() for each respective inode, because we might be finishing
* processing an inode that is a directory and it just got renamed, and existing
* entries in the cache may refer to inodes that have the directory in their
* full path - in which case we would generate outdated paths (pre-rename)
* for the inodes that the cache entries point to. Instead of prunning the
* cache when inserting, do it after we finish processing each inode at
* finish_inode_if_needed().
*/
static int cache_dir_utimes(struct send_ctx *sctx, u64 dir, u64 gen)
{
struct btrfs_lru_cache_entry *entry;
int ret;
entry = btrfs_lru_cache_lookup(&sctx->dir_utimes_cache, dir, gen);
if (entry != NULL)
return 0;
/* Caching is optional, don't fail if we can't allocate memory. */
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
return send_utimes(sctx, dir, gen);
entry->key = dir;
entry->gen = gen;
ret = btrfs_lru_cache_store(&sctx->dir_utimes_cache, entry, GFP_KERNEL);
ASSERT(ret != -EEXIST);
if (ret) {
kfree(entry);
return send_utimes(sctx, dir, gen);
}
return 0;
}
static int trim_dir_utimes_cache(struct send_ctx *sctx)
{
while (sctx->dir_utimes_cache.size > SEND_MAX_DIR_UTIMES_CACHE_SIZE) {
struct btrfs_lru_cache_entry *lru;
int ret;
lru = btrfs_lru_cache_lru_entry(&sctx->dir_utimes_cache);
ASSERT(lru != NULL);
ret = send_utimes(sctx, lru->key, lru->gen);
if (ret)
return ret;
btrfs_lru_cache_remove(&sctx->dir_utimes_cache, lru);
}
return 0;
}
/*
* 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;
struct btrfs_inode_info info;
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, &info);
if (ret < 0)
goto out;
gen = info.gen;
mode = info.mode;
rdev = info.rdev;
} 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;
}
static void cache_dir_created(struct send_ctx *sctx, u64 dir)
{
struct btrfs_lru_cache_entry *entry;
int ret;
/* Caching is optional, ignore any failures. */
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
return;
entry->key = dir;
entry->gen = 0;
ret = btrfs_lru_cache_store(&sctx->dir_created_cache, entry, GFP_KERNEL);
if (ret < 0)
kfree(entry);
}
/*
* 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;
int iter_ret = 0;
struct btrfs_path *path = NULL;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_key di_key;
struct btrfs_dir_item *di;
if (btrfs_lru_cache_lookup(&sctx->dir_created_cache, dir, 0))
return 1;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = dir;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
btrfs_for_each_slot(sctx->send_root, &key, &found_key, path, iter_ret) {
struct extent_buffer *eb = path->nodes[0];
if (found_key.objectid != key.objectid ||
found_key.type != key.type) {
ret = 0;
break;
}
di = btrfs_item_ptr(eb, path->slots[0], 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;
cache_dir_created(sctx, dir);
break;
}
}
/* Catch error found during iteration */
if (iter_ret < 0)
ret = iter_ret;
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;
}
ret = send_create_inode(sctx, sctx->cur_ino);
if (ret == 0 && S_ISDIR(sctx->cur_inode_mode))
cache_dir_created(sctx, sctx->cur_ino);
return ret;
}
struct recorded_ref {
struct list_head list;
char *name;
struct fs_path *full_path;
u64 dir;
u64 dir_gen;
int name_len;
struct rb_node node;
struct rb_root *root;
};
static struct recorded_ref *recorded_ref_alloc(void)
{
struct recorded_ref *ref;
ref = kzalloc(sizeof(*ref), GFP_KERNEL);
if (!ref)
return NULL;
RB_CLEAR_NODE(&ref->node);
INIT_LIST_HEAD(&ref->list);
return ref;
}
static void recorded_ref_free(struct recorded_ref *ref)
{
if (!ref)
return;
if (!RB_EMPTY_NODE(&ref->node))
rb_erase(&ref->node, ref->root);
list_del(&ref->list);
fs_path_free(ref->full_path);
kfree(ref);
}
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;
}
static int dup_ref(struct recorded_ref *ref, struct list_head *list)
{
struct recorded_ref *new;
new = recorded_ref_alloc();
if (!new)
return -ENOMEM;
new->dir = ref->dir;
new->dir_gen = ref->dir_gen;
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);
recorded_ref_free(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;
odi->dir_high_seq_ino = 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)