ceph: prevent snapshot creation in encrypted locked directories

With snapshot names encryption we can not allow snapshots to be created in
locked directories because the names wouldn't be encrypted.  This patch
forces the directory to be unlocked to allow a snapshot to be created.

Signed-off-by: Luís Henriques <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Reviewed-by: Xiubo Li <[email protected]>
Reviewed-by: Milind Changire <[email protected]>
Signed-off-by: Ilya Dryomov <[email protected]>

Author: Luís Henriques

fs/ceph/dir.c

@@ -1090,6 +1090,11 @@ static int ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		err = -EDQUOT;
 		goto out;
 	}
+	if ((op == CEPH_MDS_OP_MKSNAP) && IS_ENCRYPTED(dir) &&
+	    !fscrypt_has_encryption_key(dir)) {
+		err = -ENOKEY;
+		goto out;
+	}
 
 
 	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);