Btrfs: do not delete a subvolume which is in a R/O subvolume
Step to reproduce:
# mkfs.btrfs <disk>
# mount <disk> <mnt>
# btrfs sub create <mnt>/subv0
# btrfs sub snap <mnt> <mnt>/subv0/snap0
# change <mnt>/subv0 from R/W to R/O
# btrfs sub del <mnt>/subv0/snap0
We deleted the snapshot successfully. I think we should not be able to delete
the snapshot since the parent subvolume is R/O.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index dd8e344..5a72896 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2095,13 +2095,13 @@
err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
if (err)
goto out_dput;
-
- /* check if subvolume may be deleted by a non-root user */
- err = btrfs_may_delete(dir, dentry, 1);
- if (err)
- goto out_dput;
}
+ /* check if subvolume may be deleted by a user */
+ err = btrfs_may_delete(dir, dentry, 1);
+ if (err)
+ goto out_dput;
+
if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
err = -EINVAL;
goto out_dput;
