[PATCH 3.10 69/77] Btrfs: send, dont error in the presence of subvols/snapshots

Greg Kroah-Hartman
2014-06-28T19:02:00Z

From: Filipe Manana <fdmanana@gmail.com>

commit 1af56070e3ef9477dbc7eba3b9ad7446979c7974 upstream.

If we are doing an incremental send and the base snapshot has a
directory with name X that doesn't exist anymore in the second
snapshot and a new subvolume/snapshot exists in the second snapshot
that has the same name as the directory (name X), the incremental
send would fail with -ENOENT error. This is because it attempts
to lookup for an inode with a number matching the objectid of a
root, which doesn't exist.

Steps to reproduce:

mkfs.btrfs -f /dev/sdd
mount /dev/sdd /mnt

mkdir /mnt/testdir
btrfs subvolume snapshot -r /mnt /mnt/mysnap1

rmdir /mnt/testdir
btrfs subvolume create /mnt/testdir
btrfs subvolume snapshot -r /mnt /mnt/mysnap2

btrfs send -p /mnt/mysnap1 /mnt/mysnap2 -f /tmp/send.data

A test case for xfstests follows.

Reported-by: Robert White <rwhite@pobox.com>
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/btrfs/send.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -1550,6 +1550,10 @@ static int lookup_dir_item_inode(struct
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);