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linux/fs/btrfs/send.c
Jeff Mahoney 3a45bb207e btrfs: remove root parameter from transaction commit/end routines 
Now we only use the root parameter to print the root objectid in
a tracepoint.  We can use the root parameter from the transaction
handle for that.  It's also used to join the transaction with
async commits, so we remove the comment that it's just for checking.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06 16:07:00 +01:00

6460 lines
153 KiB
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/*
* Copyright (C) 2012 Alexander Block. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/bsearch.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/sort.h>
#include <linux/mount.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/radix-tree.h>
#include <linux/vmalloc.h>
#include <linux/string.h>
#include "send.h"
#include "backref.h"
#include "hash.h"
#include "locking.h"
#include "disk-io.h"
#include "btrfs_inode.h"
#include "transaction.h"
#include "compression.h"
/*
* 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 */
struct btrfs_root *send_root;
struct btrfs_root *parent_root;
struct clone_root *clone_roots;
int clone_roots_cnt;
/* current state of the compare_tree call */
struct btrfs_path *left_path;
struct btrfs_path *right_path;
struct btrfs_key *cmp_key;
/*
* infos of the currently processed inode. In case of deleted inodes,
* these are the values from the deleted inode.
*/
u64 cur_ino;
u64 cur_inode_gen;
int cur_inode_new;
int cur_inode_new_gen;
int cur_inode_deleted;
u64 cur_inode_size;
u64 cur_inode_mode;
u64 cur_inode_rdev;
u64 cur_inode_last_extent;
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;
char *read_buf;
/*
* 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;
bool orphanized;
};
struct orphan_dir_info {
struct rb_node node;
u64 ino;
u64 gen;
};
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[];
};
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));
}
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);
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;
mm_segment_t old_fs;
u32 pos = 0;
old_fs = get_fs();
set_fs(KERNEL_DS);
while (pos < len) {
ret = vfs_write(filp, (__force const char __user *)buf + pos,
len - pos, off);
/* TODO handle that correctly */
/*if (ret == -ERESTARTSYS) {
continue;
}*/
if (ret < 0)
goto out;
if (ret == 0) {
ret = -EIO;
goto out;
}
pos += ret;
}
ret = 0;
out:
set_fs(old_fs);
return ret;
}
static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len)
{
struct btrfs_tlv_header *hdr;
int total_len = sizeof(*hdr) + len;
int left = sctx->send_max_size - sctx->send_size;
if (unlikely(left < total_len))
return -EOVERFLOW;
hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size);
hdr->tlv_type = cpu_to_le16(attr);
hdr->tlv_len = cpu_to_le16(len);
memcpy(hdr + 1, data, len);
sctx->send_size += total_len;
return 0;
}
#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, attrlen, data) \
do { \
ret = tlv_put(sctx, attrtype, attrlen, data); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
#define TLV_PUT_INT(sctx, attrtype, bits, value) \
do { \
ret = tlv_put_u##bits(sctx, attrtype, value); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
#define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data)
#define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data)
#define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data)
#define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data)
#define TLV_PUT_STRING(sctx, attrtype, str, len) \
do { \
ret = tlv_put_string(sctx, attrtype, str, len); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
#define TLV_PUT_PATH(sctx, attrtype, p) \
do { \
ret = tlv_put_string(sctx, attrtype, p->start, \
p->end - p->start); \
if (ret < 0) \
goto tlv_put_failure; \
} while(0)
#define TLV_PUT_UUID(sctx, attrtype, uuid) \
do { \
ret = tlv_put_uuid(sctx, attrtype, uuid); \
if (ret < 0) \
goto tlv_put_failure; \
} while (0)
#define TLV_PUT_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;
hdr->cmd = cpu_to_le16(cmd);
return 0;
}
static int send_cmd(struct send_ctx *sctx)
{
int ret;
struct btrfs_cmd_header *hdr;
u32 crc;
hdr = (struct btrfs_cmd_header *)sctx->send_buf;
hdr->len = cpu_to_le32(sctx->send_size - sizeof(*hdr));
hdr->crc = 0;
crc = btrfs_crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
hdr->crc = cpu_to_le32(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[le16_to_cpu(hdr->cmd)] += sctx->send_size;
sctx->send_size = 0;
return ret;
}
/*
* Sends a move instruction to user space
*/
static int send_rename(struct send_ctx *sctx,
struct fs_path *from, struct fs_path *to)
{
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_item *item;
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);
item = btrfs_item_nr(slot);
total = btrfs_item_size(eb, item);
elem_size = sizeof(*iref);
} else {
ptr = btrfs_item_ptr_offset(eb, slot);
total = btrfs_item_size_nr(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,
u8 type, void *ctx);
/*
* Helper function to iterate the entries in ONE btrfs_dir_item.
* The iterate callback may return a non zero value to stop iteration. This can
* be a negative value for error codes or 1 to simply stop it.
*
* path must point to the dir item when called.
*/
static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *found_key,
iterate_dir_item_t iterate, void *ctx)
{
int ret = 0;
struct extent_buffer *eb;
struct btrfs_item *item;
struct btrfs_dir_item *di;
struct btrfs_key di_key;
char *buf = NULL;
int buf_len;
u32 name_len;
u32 data_len;
u32 cur;
u32 len;
u32 total;
int slot;
int num;
u8 type;
/*
* 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];
item = btrfs_item_nr(slot);
di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
cur = 0;
len = 0;
total = btrfs_item_size(eb, item);
num = 0;
while (cur < total) {
name_len = btrfs_dir_name_len(eb, di);
data_len = btrfs_dir_data_len(eb, di);
type = btrfs_dir_type(eb, di);
btrfs_dir_item_key_to_cpu(eb, di, &di_key);
if (type == 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 = vmalloc(buf_len);
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, type, 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;
struct btrfs_path *path;
/* 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;
/* data offset in the file extent item */
u64 data_offset;
/* 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;
struct clone_root *cr = (struct clone_root *)elt;
if (root < cr->root->objectid)
return -1;
if (root > cr->root->objectid)
return 1;
return 0;
}
static int __clone_root_cmp_sort(const void *e1, const void *e2)
{
struct clone_root *cr1 = (struct clone_root *)e1;
struct clone_root *cr2 = (struct clone_root *)e2;
if (cr1->root->objectid < cr2->root->objectid)
return -1;
if (cr1->root->objectid > cr2->root->objectid)
return 1;
return 0;
}
/*
* Called for every backref that is found for the current extent.
* 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;
int ret;
u64 i_size;
/* 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;
}
/*
* There are inodes that have extents that lie behind its i_size. Don't
* accept clones from these extents.
*/
ret = __get_inode_info(found->root, bctx->path, ino, &i_size, NULL, NULL,
NULL, NULL, NULL);
btrfs_release_path(bctx->path);
if (ret < 0)
return ret;
if (offset + bctx->data_offset + bctx->extent_len > i_size)
return 0;
/*
* Make sure we don't consider clones from send_root that are
* behind the current inode/offset.
*/
if (found->root == bctx->sctx->send_root) {
/*
* TODO for the moment we don't accept clones from the inode
* that is currently send. We may change this when
* BTRFS_IOC_CLONE_RANGE supports cloning from and to the same
* file.
*/
if (ino >= bctx->cur_objectid)
return 0;
#if 0
if (ino > bctx->cur_objectid)
return 0;
if (offset + bctx->extent_len > bctx->cur_offset)
return 0;
#endif
}
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 = NULL;
struct clone_root *cur_clone_root;
struct btrfs_key found_key;
struct btrfs_path *tmp_path;
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;
backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_KERNEL);
if (!backref_ctx) {
ret = -ENOMEM;
goto out;
}
backref_ctx->path = tmp_path;
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);
btrfs_release_path(tmp_path);
if (ret < 0)
goto out;
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
ret = -EIO;
goto out;
}
/*
* Setup the clone roots.
*/
for (i = 0; i < sctx->clone_roots_cnt; i++) {
cur_clone_root = sctx->clone_roots + i;
cur_clone_root->ino = (u64)-1;
cur_clone_root->offset = 0;
cur_clone_root->found_refs = 0;
}
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;
/*
* For non-compressed extents iterate_extent_inodes() gives us extent
* offsets that already take into account the data offset, but not for
* compressed extents, since the offset is logical and not relative to
* the physical extent locations. We must take this into account to
* avoid sending clone offsets that go beyond the source file's size,
* which would result in the clone ioctl failing with -EINVAL on the
* receiving end.
*/
if (compressed == BTRFS_COMPRESS_NONE)
backref_ctx->data_offset = 0;
else
backref_ctx->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;
/*
* 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);
if (ret < 0)
goto out;
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);
kfree(backref_ctx);
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_inline_len(path->nodes[0], path->slots[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;
ret = get_cur_inode_state(sctx, ino, gen);
if (ret < 0)
goto out;
if (ret == inode_state_no_change ||
ret == inode_state_did_create ||
ret == inode_state_will_delete)
ret = 1;
else
ret = 0;
out:
return ret;
}
/*
* Helper function to lookup a dir item in a dir.
*/
static int lookup_dir_item_inode(struct btrfs_root *root,
u64 dir, const char *name, int name_len,
u64 *found_inode,
u8 *found_type)
{
int ret = 0;
struct btrfs_dir_item *di;
struct btrfs_key key;
struct btrfs_path *path;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
di = btrfs_lookup_dir_item(NULL, root, path,
dir, name, name_len, 0);
if (!di) {
ret = -ENOENT;
goto out;
}
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
if (key.type == BTRFS_ROOT_ITEM_KEY) {
ret = -ENOENT;
goto out;
}
*found_inode = key.objectid;
*found_type = btrfs_dir_type(path->nodes[0], di);
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)
{
int ret = 0;
u64 gen;
u64 other_inode = 0;
u8 other_type = 0;
if (!sctx->parent_root)
goto out;
ret = is_inode_existent(sctx, dir, dir_gen);
if (ret <= 0)
goto out;
/*
* 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) {
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, &other_type);
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, NULL, 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;
u8 other_type;
if (!sctx->parent_root)
goto out;
ret = is_inode_existent(sctx, dir, dir_gen);
if (ret <= 0)
goto out;
/* check if the ref was overwritten by another ref */
ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
&ow_inode, &other_type);
if (ret < 0 && ret != -ENOENT)
goto out;
if (ret) {
/* was never and will never be overwritten */
ret = 0;
goto out;
}
ret = get_inode_info(sctx->send_root, ow_inode, NULL, &gen, NULL, NULL,
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;
}
/*
* 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.
*/
static void name_cache_used(struct send_ctx *sctx, struct name_cache_entry *nce)
{
list_del(&nce->list);
list_add_tail(&nce->list, &sctx->name_cache_list);
}
/*
* 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 {
name_cache_used(sctx, nce);
*parent_ino = nce->parent_ino;
*parent_gen = nce->parent_gen;
ret = fs_path_add(dest, nce->name, nce->name_len);
if (ret < 0)
goto out;
ret = nce->ret;
goto out;
}
}
/*
* 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 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)) {
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->objectid;
key.type = BTRFS_ROOT_BACKREF_KEY;
key.offset = 0;
ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root,
&key, path, 1, 0);
if (ret < 0)
goto out;
if (ret) {
ret = -ENOENT;
goto out;
}
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.type != BTRFS_ROOT_BACKREF_KEY ||
key.objectid != send_root->objectid) {
ret = -ENOENT;
goto out;
}
ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
namelen = btrfs_root_ref_name_len(leaf, ref);
read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen);
btrfs_release_path(path);
if (parent_root) {
ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT);
if (ret < 0)
goto out;
} else {
ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL);
if (ret < 0)
goto out;
}
TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen);
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,
le64_to_cpu(sctx->send_root->root_item.ctransid));
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,
le64_to_cpu(sctx->parent_root->root_item.ctransid));
}
ret = send_cmd(sctx);
tlv_put_failure:
out:
btrfs_free_path(path);
kfree(name);
return ret;
}
static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size)
{
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 = -ENOTSUPP;
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)
goto out;
if (ret) {
ret = 0;
goto out;
}
}
ret = send_create_inode(sctx, sctx->cur_ino);
if (ret < 0)
goto out;
out:
return ret;
}
struct recorded_ref {
struct list_head list;
char *dir_path;
char *name;
struct fs_path *full_path;
u64 dir;
u64 dir_gen;
int dir_path_len;
int name_len;
};
/*
* We need to process new refs before deleted refs, but compare_tree gives us
* everything mixed. So we first record all refs and later process them.
* This function is a helper to record one ref.
*/
static int __record_ref(struct list_head *head, u64 dir,
u64 dir_gen, struct fs_path *path)
{
struct recorded_ref *ref;
ref = kmalloc(sizeof(*ref), GFP_KERNEL);
if (!ref)
return -ENOMEM;
ref->dir = dir;
ref->dir_gen = dir_gen;
ref->full_path = path;
ref->name = (char *)kbasename(ref->full_path->start);
ref->name_len = ref->full_path->end - ref->name;
ref->dir_path = ref->full_path->start;
if (ref->name == ref->full_path->start)
ref->dir_path_len = 0;
else
ref->dir_path_len = ref->full_path->end -
ref->full_path->start - 1 - ref->name_len;
list_add_tail(&ref->list, head);
return 0;
}
static 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)
{
struct rb_node **p = &sctx->orphan_dirs.rb_node;
struct rb_node *parent = NULL;
struct orphan_dir_info *entry, *odi;
odi = kmalloc(sizeof(*odi), GFP_KERNEL);
if (!odi)
return ERR_PTR(-ENOMEM);
odi->ino = dir_ino;
odi->gen = 0;
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 {
kfree(odi);
return entry;
}
}
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)
{
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
return entry;
}
return NULL;
}
static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino)
{
struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino);
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;
/*
* 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;
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) {
struct orphan_dir_info *odi;
odi = add_orphan_dir_info(sctx, dir);
if (IS_ERR(odi)) {
ret = PTR_ERR(odi);
goto out;
}
odi->gen = dir_gen;
dm->rmdir_ino = dir;
ret = 0;
goto out;
}
if (loc.objectid > send_progress) {
struct orphan_dir_info *odi;
odi = get_orphan_dir_info(sctx, dir);
free_orphan_dir_info(sctx, odi);
ret = 0;
goto out;
}
path->slots[0]++;
}
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->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))
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 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;
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;
}
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;
odi = get_orphan_dir_info(sctx, rmdir_ino);
if (!odi) {
/* already deleted */
goto finish;
}
ret = can_rmdir(sctx, rmdir_ino, odi->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, odi->gen, name);
if (ret < 0)
goto out;
ret = send_rmdir(sctx, name);
if (ret < 0)
goto out;
free_orphan_dir_info(sctx, odi);
}
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 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);
}
}
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(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(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 ino ino1 is an ancestor of inode ino2 in the given root.
* 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)
{
u64 ino = ino2;
while (ino > BTRFS_FIRST_FREE_OBJECTID) {
int ret;
u64 parent;
u64 parent_gen;
fs_path_reset(fs_path);
ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path);
if (ret < 0) {
if (ret == -ENOENT && ino == ino2)
ret = 0;
return ret;
}
if (parent == ino1)
return parent_gen == ino1_gen ? 1 : 0;
ino = parent;
}
return 0;
}
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 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) {
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,
NULL, 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))) {
ret = 1;
break;
}
ino = parent_ino_after;
}
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;
}
/*
* 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;
int did_overwrite = 0;
int is_orphan = 0;
u64 last_dir_ino_rm = 0;
bool can_rename = true;
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;
}
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
* the the current inum. To handle this case, we create the
* parent directory out of order. But we need to check if this
* did already happen before due to other refs in the same dir.
*/
ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen);
if (ret < 0)
goto out;
if (ret == inode_state_will_create) {
ret = 0;
/*
* First check if any of the current inodes refs did
* already create the dir.
*/
list_for_each_entry(cur2, &sctx->new_refs, list) {
if (cur == cur2)
break;
if (cur2->dir == cur->dir) {
ret = 1;
break;
}
}
/*
* If that did not happen, check if a previous inode
* did already create the dir.
*/
if (!ret)
ret = did_create_dir(sctx, cur->dir);
if (ret < 0)
goto out;
if (!ret) {
ret = send_create_inode(sctx, cur->dir);
if (ret < 0)
goto out;
}
}
/*
* Check if this new ref would overwrite the first ref of
* another unprocessed inode. If yes, orphanize the
* overwritten inode. If we find an overwritten ref that is
* not the first ref, simply unlink it.
*/
ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen,
cur->name, cur->name_len,
&ow_inode, &ow_gen);
if (ret < 0)
goto out;
if (ret) {
ret = is_first_ref(sctx->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;
ret = orphanize_inode(sctx, ow_inode, ow_gen,
cur->full_path);
if (ret < 0)
goto out;
/*
* 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.
*/
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 {
ret = send_unlink(sctx, cur->full_path);
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 {
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) {
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, int num, u64 dir, int index,
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, num, dir, index, 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, num, dir, index, 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,
u8 type, void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
struct fs_path *p;
struct posix_acl_xattr_header dummy_acl;
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,
u8 type, 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,
sctx->cmp_key, __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,
sctx->cmp_key, __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,
u8 type, void *vctx)
{
struct find_xattr_ctx *ctx = vctx;
if (name_len == ctx->name_len &&
strncmp(name, ctx->name, name_len) == 0) {
ctx->found_idx = num;
ctx->found_data_len = data_len;
ctx->found_data = 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, key, __find_xattr, &ctx);
if (ret < 0)
return ret;
if (ctx.found_idx == -1)
return -ENOENT;
if (data) {
*data = ctx.found_data;
*data_len = ctx.found_data_len;
} else {
kfree(ctx.found_data);
}
return ctx.found_idx;
}
static int __process_changed_new_xattr(int num, struct btrfs_key *di_key,
const char *name, int name_len,
const char *data, int data_len,
u8 type, void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
char *found_data = NULL;
int found_data_len = 0;
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, type, ctx);
} else if (ret >= 0) {
if (data_len != found_data_len ||
memcmp(data, found_data, data_len)) {
ret = __process_new_xattr(num, di_key, name, name_len,
data, data_len, type, ctx);
} else {
ret = 0;
}
}
kfree(found_data);
return ret;
}
static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key,
const char *name, int name_len,
const char *data, int data_len,
u8 type, void *ctx)
{
int ret;
struct send_ctx *sctx = ctx;
ret = find_xattr(sctx->send_root, sctx->left_path, sctx->cmp_key,
name, name_len, NULL, NULL);
if (ret == -ENOENT)
ret = __process_deleted_xattr(num, di_key, name, name_len, data,
data_len, type, ctx);
else if (ret >= 0)
ret = 0;
return ret;
}
static int process_changed_xattr(struct send_ctx *sctx)
{
int ret = 0;
ret = iterate_dir_item(sctx->send_root, sctx->left_path,
sctx->cmp_key, __process_changed_new_xattr, sctx);
if (ret < 0)
goto out;
ret = iterate_dir_item(sctx->parent_root, sctx->right_path,
sctx->cmp_key, __process_changed_deleted_xattr, sctx);
out:
return ret;
}
static int process_all_new_xattrs(struct send_ctx *sctx)
{
int ret;
struct btrfs_root *root;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key found_key;
struct extent_buffer *eb;
int slot;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
root = sctx->send_root;
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_XATTR_ITEM_KEY;
key.offset = 0;
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, &found_key,
__process_new_xattr, sctx);
if (ret < 0)
goto out;
path->slots[0]++;
}
out:
btrfs_free_path(path);
return ret;
}
static ssize_t fill_read_buf(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;
char *addr;
struct btrfs_key key;
pgoff_t index = offset >> PAGE_SHIFT;
pgoff_t last_index;
unsigned pg_offset = offset & ~PAGE_MASK;
ssize_t ret = 0;
key.objectid = sctx->cur_ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
inode = btrfs_iget(fs_info->sb, &key, root, NULL);
if (IS_ERR(inode))
return PTR_ERR(inode);
if (offset + len > i_size_read(inode)) {
if (offset > i_size_read(inode))
len = 0;
else
len = offset - i_size_read(inode);
}
if (len == 0)
goto out;
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);
btrfs_force_ra(inode->i_mapping, &sctx->ra, NULL, index,
last_index - index + 1);
while (index <= last_index) {
unsigned cur_len = min_t(unsigned, len,
PAGE_SIZE - pg_offset);
page = find_or_create_page(inode->i_mapping, index, GFP_KERNEL);
if (!page) {
ret = -ENOMEM;
break;
}
if (!PageUptodate(page)) {
btrfs_readpage(NULL, page);
lock_page(page);
if (!PageUptodate(page)) {
unlock_page(page);
put_page(page);
ret = -EIO;
break;
}
}
addr = kmap(page);
memcpy(sctx->read_buf + ret, addr + pg_offset, cur_len);
kunmap(page);
unlock_page(page);
put_page(page);
index++;
pg_offset = 0;
len -= cur_len;
ret += cur_len;
}
out:
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;
ssize_t num_read = 0;
p = fs_path_alloc();
if (!p)
return -ENOMEM;
btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len);
num_read = fill_read_buf(sctx, offset, len);
if (num_read <= 0) {
if (num_read < 0)
ret = num_read;
goto out;
}
ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
if (ret < 0)
goto out;
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
if (ret < 0)
goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, num_read);
ret = send_cmd(sctx);
tlv_put_failure:
out:
fs_path_free(p);
if (ret < 0)
return ret;
return num_read;
}
/*
* 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->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,
le64_to_cpu(clone_root->root->root_item.ctransid));
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 offset = sctx->cur_inode_last_extent;
u64 len;
int ret = 0;
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;
memset(sctx->read_buf, 0, BTRFS_SEND_READ_SIZE);
while (offset < end) {
len = min_t(u64, end - offset, BTRFS_SEND_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);
TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, len);
ret = send_cmd(sctx);
if (ret < 0)
break;
offset += len;
}
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 sent = 0;
if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
return send_update_extent(sctx, offset, len);
while (sent < len) {
u64 size = len - sent;
int ret;
if (size > BTRFS_SEND_READ_SIZE)
size = BTRFS_SEND_READ_SIZE;
ret = send_write(sctx, offset + sent, size);
if (ret < 0)
return ret;
if (!ret)
break;
sent += ret;
}
return 0;
}
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;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
/*
* 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;
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_inline_len(leaf, slot, 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;
clone_len = min_t(u64, ext_len, len);
if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte &&
btrfs_file_extent_offset(leaf, ei) == data_offset)
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;
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;
struct btrfs_file_extent_item *ei;
u64 offset = key->offset;
u64 len;
u8 type;
u64 bs = sctx->send_root->fs_info->sb->s_blocksize;
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_INLINE) {
len = btrfs_file_extent_inline_len(path->nodes[0],
path->slots[0], ei);
/*
* it is possible the inline item won't cover the whole page,
* but there may be items after this page. Make
* sure to send the whole thing
*/
len = PAGE_ALIGN(len);
} else {
len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
}
if (offset + len > sctx->cur_inode_size)
len = sctx->cur_inode_size - offset;
if (len == 0) {
ret = 0;
goto out;
}
if (clone_root && IS_ALIGNED(offset + len, bs)) {
u64 disk_byte;
u64 data_offset;
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, len);
} else {
ret = send_extent_data(sctx, offset, len);
}
out:
return ret;
}
static int is_extent_unchanged(struct send_ctx *sctx,
struct btrfs_path *left_path,
struct btrfs_key *ekey)
{
int ret = 0;
struct btrfs_key key;
struct btrfs_path *path = NULL;
struct extent_buffer *eb;
int slot;
struct btrfs_key found_key;
struct btrfs_file_extent_item *ei;
u64 left_disknr;
u64 right_disknr;
u64 left_offset;
u64 right_offset;
u64 left_offset_fixed;
u64 left_len;
u64 right_len;
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) {
ret = 0;
goto out;
}
right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
right_len = btrfs_file_extent_num_bytes(eb, ei);
right_offset = btrfs_file_extent_offset(eb, ei);
right_gen = btrfs_file_extent_generation(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;
}
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_file_extent_item *fi;
struct btrfs_key key;
u64 extent_end;
u8 type;
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;
fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_file_extent_item);
type = btrfs_file_extent_type(path->nodes[0], fi);
if (type == BTRFS_FILE_EXTENT_INLINE) {
u64 size = btrfs_file_extent_inline_len(path->nodes[0],
path->slots[0], fi);
extent_end = ALIGN(key.offset + size,
sctx->send_root->fs_info->sectorsize);
} else {
extent_end = key.offset +
btrfs_file_extent_num_bytes(path->nodes[0], fi);
}
sctx->cur_inode_last_extent = extent_end;
out:
btrfs_free_path(path);
return ret;
}
static int maybe_send_hole(struct send_ctx *sctx, struct btrfs_path *path,
struct btrfs_key *key)
{
struct btrfs_file_extent_item *fi;
u64 extent_end;
u8 type;
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;
}
fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_file_extent_item);
type = btrfs_file_extent_type(path->nodes[0], fi);
if (type == BTRFS_FILE_EXTENT_INLINE) {
u64 size = btrfs_file_extent_inline_len(path->nodes[0],
path->slots[0], fi);
extent_end = ALIGN(key->offset + size,
sctx->send_root->fs_info->sectorsize);
} else {
extent_end = key->offset +
btrfs_file_extent_num_bytes(path->nodes[0], fi);
}
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 = send_hole(sctx, key->offset);
sctx->cur_inode_last_extent = extent_end;
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 pending_move = 0;
int refs_processed = 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;
} else {
ret = get_inode_info(sctx->parent_root, sctx->cur_ino,
NULL, 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 (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;
}
}
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;
}
/*
* 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;
}
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;
/*
* 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;
}
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;
if (sctx->cur_ino != sctx->cmp_key->objectid) {
if (result == BTRFS_COMPARE_TREE_CHANGED) {
struct extent_buffer *leaf_l;
struct extent_buffer *leaf_r;
struct btrfs_file_extent_item *ei_l;
struct btrfs_file_extent_item *ei_r;
leaf_l = sctx->left_path->nodes[0];
leaf_r = sctx->right_path->nodes[0];
ei_l = btrfs_item_ptr(leaf_l,
sctx->left_path->slots[0],
struct btrfs_file_extent_item);
ei_r = btrfs_item_ptr(leaf_r,
sctx->right_path->slots[0],
struct btrfs_file_extent_item);
/*
* We may have found an extent item that has changed
* only its disk_bytenr field and the corresponding
* inode item was not updated. This case happens due to
* very specific timings during relocation when a leaf
* that contains file extent items is COWed while
* relocation is ongoing and its in the stage where it
* updates data pointers. So when this happens we can
* safely ignore it since we know it's the same extent,
* but just at different logical and physical locations
* (when an extent is fully replaced with a new one, we
* know the generation number must have changed too,
* since snapshot creation implies committing the current
* transaction, and the inode item must have been updated
* as well).
* This replacement of the disk_bytenr happens at
* relocation.c:replace_file_extents() through
* relocation.c:btrfs_reloc_cow_block().
*/
if (btrfs_file_extent_generation(leaf_l, ei_l) ==
btrfs_file_extent_generation(leaf_r, ei_r) &&
btrfs_file_extent_ram_bytes(leaf_l, ei_l) ==
btrfs_file_extent_ram_bytes(leaf_r, ei_r) &&
btrfs_file_extent_compression(leaf_l, ei_l) ==
btrfs_file_extent_compression(leaf_r, ei_r) &&
btrfs_file_extent_encryption(leaf_l, ei_l) ==
btrfs_file_extent_encryption(leaf_r, ei_r) &&
btrfs_file_extent_other_encoding(leaf_l, ei_l) ==
btrfs_file_extent_other_encoding(leaf_r, ei_r) &&
btrfs_file_extent_type(leaf_l, ei_l) ==
btrfs_file_extent_type(leaf_r, ei_r) &&
btrfs_file_extent_disk_bytenr(leaf_l, ei_l) !=
btrfs_file_extent_disk_bytenr(leaf_r, ei_r) &&
btrfs_file_extent_disk_num_bytes(leaf_l, ei_l) ==
btrfs_file_extent_disk_num_bytes(leaf_r, ei_r) &&
btrfs_file_extent_offset(leaf_l, ei_l) ==
btrfs_file_extent_offset(leaf_r, ei_r) &&
btrfs_file_extent_num_bytes(leaf_l, ei_l) ==
btrfs_file_extent_num_bytes(leaf_r, ei_r))
return 0;
}
inconsistent_snapshot_error(sctx, result, "extent");
return -EIO;
}
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_nr(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_root *left_root,
struct btrfs_root *right_root,
struct btrfs_path *left_path,
struct btrfs_path *right_path,
struct btrfs_key *key,
enum btrfs_compare_tree_result result,
void *ctx)
{
int ret = 0;
struct send_ctx *sctx = ctx;
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 (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 full_send_tree(struct send_ctx *sctx)
{
int ret;
struct btrfs_root *send_root = sctx->send_root;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_path *path;
struct extent_buffer *eb;
int slot;
path = alloc_path_for_send();
if (!path)
return -ENOMEM;
key.objectid = BTRFS_FIRST_FREE_OBJECTID;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret)
goto out_finish;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
ret = changed_cb(send_root, NULL, path, NULL,
&found_key, BTRFS_COMPARE_TREE_NEW, sctx);
if (ret < 0)
goto out;
key.objectid = found_key.objectid;
key.type = found_key.type;
key.offset = found_key.offset + 1;
ret = btrfs_next_item(send_root, path);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
break;
}
}
out_finish:
ret = finish_inode_if_needed(sctx, 1);
out:
btrfs_free_path(path);
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,
changed_cb, sctx);
if (ret < 0)
goto out;
ret = finish_inode_if_needed(sctx, 1);
if (ret < 0)
goto out;
} else {
ret = full_send_tree(sctx);
if (ret < 0)
goto out;
}
out:
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);
}
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_progres unbalanced %d root %llu",
root->send_in_progress, root->root_key.objectid);
spin_unlock(&root->root_item_lock);
}
long btrfs_ioctl_send(struct file *mnt_file, void __user *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 btrfs_ioctl_send_args *arg = NULL;
struct btrfs_key key;
struct send_ctx *sctx = NULL;
u32 i;
u64 *clone_sources_tmp = NULL;
int clone_sources_to_rollback = 0;
unsigned alloc_size;
int sort_clone_roots = 0;
int index;
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);
send_root->send_in_progress++;
spin_unlock(&send_root->root_item_lock);
/*
* This is done when we lookup the root, it should already be complete
* by the time we get here.
*/
WARN_ON(send_root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE);
/*
* Userspace tools do the checks and warn the user if it's
* not RO.
*/
if (!btrfs_root_readonly(send_root)) {
ret = -EPERM;
goto out;
}
arg = memdup_user(arg_, sizeof(*arg));
if (IS_ERR(arg)) {
ret = PTR_ERR(arg);
arg = NULL;
goto out;
}
if (arg->clone_sources_count >
ULLONG_MAX / sizeof(*arg->clone_sources)) {
ret = -EINVAL;
goto out;
}
if (!access_ok(VERIFY_READ, arg->clone_sources,
sizeof(*arg->clone_sources) *
arg->clone_sources_count)) {
ret = -EFAULT;
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;
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 = kmalloc(sctx->send_max_size, GFP_KERNEL | __GFP_NOWARN);
if (!sctx->send_buf) {
sctx->send_buf = vmalloc(sctx->send_max_size);
if (!sctx->send_buf) {
ret = -ENOMEM;
goto out;
}
}
sctx->read_buf = kmalloc(BTRFS_SEND_READ_SIZE, GFP_KERNEL | __GFP_NOWARN);
if (!sctx->read_buf) {
sctx->read_buf = vmalloc(BTRFS_SEND_READ_SIZE);
if (!sctx->read_buf) {
ret = -ENOMEM;
goto out;
}
}
sctx->pending_dir_moves = RB_ROOT;
sctx->waiting_dir_moves = RB_ROOT;
sctx->orphan_dirs = RB_ROOT;
alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1);
sctx->clone_roots = kzalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN);
if (!sctx->clone_roots) {
sctx->clone_roots = vzalloc(alloc_size);
if (!sctx->clone_roots) {
ret = -ENOMEM;
goto out;
}
}
alloc_size = arg->clone_sources_count * sizeof(*arg->clone_sources);
if (arg->clone_sources_count) {
clone_sources_tmp = kmalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN);
if (!clone_sources_tmp) {
clone_sources_tmp = vmalloc(alloc_size);
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++) {
key.objectid = clone_sources_tmp[i];
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = (u64)-1;
index = srcu_read_lock(&fs_info->subvol_srcu);
clone_root = btrfs_read_fs_root_no_name(fs_info, &key);
if (IS_ERR(clone_root)) {
srcu_read_unlock(&fs_info->subvol_srcu, index);
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);
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = -EPERM;
goto out;
}
clone_root->send_in_progress++;
spin_unlock(&clone_root->root_item_lock);
srcu_read_unlock(&fs_info->subvol_srcu, index);
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) {
key.objectid = arg->parent_root;
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = (u64)-1;
index = srcu_read_lock(&fs_info->subvol_srcu);
sctx->parent_root = btrfs_read_fs_root_no_name(fs_info, &key);
if (IS_ERR(sctx->parent_root)) {
srcu_read_unlock(&fs_info->subvol_srcu, index);
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);
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = -EPERM;
goto out;
}
spin_unlock(&sctx->parent_root->root_item_lock);
srcu_read_unlock(&fs_info->subvol_srcu, index);
}
/*
* Clones from send_root are allowed, but only if the clone source
* is behind the current send position. This is checked while searching
* for possible clone sources.
*/
sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root;
/* We do a bsearch later */
sort(sctx->clone_roots, sctx->clone_roots_cnt,
sizeof(*sctx->clone_roots), __clone_root_cmp_sort,
NULL);
sort_clone_roots = 1;
ret = ensure_commit_roots_uptodate(sctx);
if (ret)
goto out;
current->journal_info = BTRFS_SEND_TRANS_STUB;
ret = send_subvol(sctx);
current->journal_info = NULL;
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);
} else {
for (i = 0; sctx && i < clone_sources_to_rollback; i++)
btrfs_root_dec_send_in_progress(
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);
kfree(arg);
kvfree(clone_sources_tmp);
if (sctx) {
if (sctx->send_filp)
fput(sctx->send_filp);
kvfree(sctx->clone_roots);
kvfree(sctx->send_buf);
kvfree(sctx->read_buf);
name_cache_free(sctx);
kfree(sctx);
}
return ret;
}
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