gfs2: 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.

In the "nolock" case however, there is no need to deny them.

Fixes: e6d28ebc17 ("filelock: push the S_ISREG check down to ->setlease handlers")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260107-setlease-6-19-v1-4-85f034abcc57@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/gfs2/file.c

@@ -1608,6 +1608,7 @@ const struct file_operations gfs2_dir_fops = {
 	.lock		= gfs2_lock,
 	.flock		= gfs2_flock,
 	.llseek		= default_llseek,
+	.setlease	= simple_nosetlease,
 	.fop_flags	= FOP_ASYNC_LOCK,
 };