[PATCH 3.12 170/181] Btrfs: send, don't error in the presence of subvols/snapshots

From: Jiri Slaby
Date: Mon Jun 30 2014 - 08:30:32 EST


From: Filipe Manana <fdmanana@xxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

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@xxxxxxxxx>
Signed-off-by: Filipe David Borba Manana <fdmanana@xxxxxxxxx>
Signed-off-by: Chris Mason <clm@xxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
fs/btrfs/send.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 741c839fa46a..76736b57de5e 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -1547,6 +1547,10 @@ static int lookup_dir_item_inode(struct btrfs_root *root,
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);

--
2.0.0

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