Btrfs: add extra sanity checks on the path names in btrfs_mksubvol

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index e9bdb8b783e5..05446f77f99b 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1333,6 +1333,12 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
                 goto out;
         }
 
+        if (name[0] == '.' &&
+           (namelen == 1 || (name[1] == '.' && namelen == 2))) {
+                ret = -EEXIST;
+                goto out;
+        }
+
         if (subvol) {
                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
                                      NULL, transid, readonly);