ceph: don't allow delegations to be set on directories

With the advent of directory leases, it's necessary to set the
->setlease() handler in directory file_operations to properly deny them.

Fixes: e6d28ebc17eb ("filelock: push the S_ISREG check down to ->setlease handlers")
Signed-off-by: Jeff Layton <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Reviewed-by: Viacheslav Dubeyko <[e-mail]>
Signed-off-by: Christian Brauner <[e-mail]>

fs/ceph/dir.c

···
 	.fsync = ceph_fsync,
 	.lock = ceph_lock,
 	.flock = ceph_flock,
+	.setlease = simple_nosetlease,
 };
 
 const struct file_operations ceph_snapdir_fops = {
···
 	.llseek = ceph_dir_llseek,
 	.open = ceph_open,
 	.release = ceph_release,
+	.setlease = simple_nosetlease,
 };
 
 const struct inode_operations ceph_dir_iops = {