From: Josef Bacik josef@toxicpanda.com
commit 943eb3bf25f4a7b745dd799e031be276aa104d82 upstream.
If we're rename exchanging two subvols we'll try to lock this lock twice, which is bad. Just lock once if either of the ino's are subvols.
Fixes: cdd1fedf8261 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik josef@toxicpanda.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/inode.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
--- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -9820,9 +9820,8 @@ static int btrfs_rename_exchange(struct return -EXDEV;
/* close the race window with snapshot create/destroy ioctl */ - if (old_ino == BTRFS_FIRST_FREE_OBJECTID) - down_read(&fs_info->subvol_sem); - if (new_ino == BTRFS_FIRST_FREE_OBJECTID) + if (old_ino == BTRFS_FIRST_FREE_OBJECTID || + new_ino == BTRFS_FIRST_FREE_OBJECTID) down_read(&fs_info->subvol_sem);
/* @@ -10014,9 +10013,8 @@ out_fail: ret2 = btrfs_end_transaction(trans); ret = ret ? ret : ret2; out_notrans: - if (new_ino == BTRFS_FIRST_FREE_OBJECTID) - up_read(&fs_info->subvol_sem); - if (old_ino == BTRFS_FIRST_FREE_OBJECTID) + if (new_ino == BTRFS_FIRST_FREE_OBJECTID || + old_ino == BTRFS_FIRST_FREE_OBJECTID) up_read(&fs_info->subvol_sem);
return ret;