mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-05 18:39:59 +00:00
Btrfs: send, allow clone operations within the same file
For send we currently skip clone operations when the source and
destination files are the same. This is so because clone didn't support
this case in its early days, but support for it was added back in May
2013 by commit a96fbc7288
("Btrfs: allow file data clone within a
file"). This change adds support for it.
Example:
$ mkfs.btrfs -f /dev/sdd
$ mount /dev/sdd /mnt/sdd
$ xfs_io -f -c "pwrite -S 0xab -b 64K 0 64K" /mnt/sdd/foobar
$ xfs_io -c "reflink /mnt/sdd/foobar 0 64K 64K" /mnt/sdd/foobar
$ btrfs subvolume snapshot -r /mnt/sdd /mnt/sdd/snap
$ mkfs.btrfs -f /dev/sde
$ mount /dev/sde /mnt/sde
$ btrfs send /mnt/sdd/snap | btrfs receive /mnt/sde
Without this change file foobar at the destination has a single 128Kb
extent:
$ filefrag -v /mnt/sde/snap/foobar
Filesystem type is: 9123683e
File size of /mnt/sde/snap/foobar is 131072 (32 blocks of 4096 bytes)
ext: logical_offset: physical_offset: length: expected: flags:
0: 0.. 31: 0.. 31: 32: last,unknown_loc,delalloc,eof
/mnt/sde/snap/foobar: 1 extent found
With this we get a single 64Kb extent that is shared at file offsets 0
and 64K, just like in the source filesystem:
$ filefrag -v /mnt/sde/snap/foobar
Filesystem type is: 9123683e
File size of /mnt/sde/snap/foobar is 131072 (32 blocks of 4096 bytes)
ext: logical_offset: physical_offset: length: expected: flags:
0: 0.. 15: 3328.. 3343: 16: shared
1: 16.. 31: 3328.. 3343: 16: 3344: last,shared,eof
/mnt/sde/snap/foobar: 2 extents found
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
parent
6b7faadd98
commit
11f2069c11
1 changed files with 13 additions and 5 deletions
|
@ -1248,12 +1248,20 @@ static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_)
|
|||
*/
|
||||
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 the source inode was not yet processed we can't issue a
|
||||
* clone operation, as the source extent does not exist yet at
|
||||
* the destination of the stream.
|
||||
*/
|
||||
if (ino >= bctx->cur_objectid)
|
||||
if (ino > bctx->cur_objectid)
|
||||
return 0;
|
||||
/*
|
||||
* We clone from the inode currently being sent as long as the
|
||||
* source extent is already processed, otherwise we could try
|
||||
* to clone from an extent that does not exist yet at the
|
||||
* destination of the stream.
|
||||
*/
|
||||
if (ino == bctx->cur_objectid &&
|
||||
offset >= bctx->sctx->cur_inode_next_write_offset)
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue