Linux 6.14: dops->d_revalidate now takes four args

This is a convenience for filesystems that need the inode of their
parent or their own name, as its often complicated to get that
information. We don't need those things, so this is just detecting which
prototype is expected and adjusting our callback to match.

Sponsored-by: https://despairlabs.com/sponsor/
Signed-off-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
(cherry picked from commit 7ef6b70e96)

module/os/linux/zfs/zpl_ctldir.c

@@ -185,8 +185,14 @@ zpl_snapdir_automount(struct path *path)
  * as of the 3.18 kernel revaliding the mountpoint dentry will result in
  * the snapshot being immediately unmounted.
  */
+#ifdef HAVE_D_REVALIDATE_4ARGS
+static int
+zpl_snapdir_revalidate(struct inode *dir, const struct qstr *name,
+    struct dentry *dentry, unsigned int flags)
+#else
 static int
 zpl_snapdir_revalidate(struct dentry *dentry, unsigned int flags)
+#endif
 {
 	return (!!dentry->d_inode);
 }