Checking for S_ISREG() in nfs4_setlease() is incorrect, since that op is
never called for directories. The right way to deny lease requests on
directories is to set the ->setlease() operation to simple_nosetlease()
in the directory file_operations.

Fixes: e6d28ebc17eb ("filelock: push the S_ISREG check down to ->setlease handlers")
Reported-by: Christoph Hellwig <hch@infradead.org>
Closes: https://lore.kernel.org/linux-fsdevel/aV316LhsVSl0n9-E@infradead.org/
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfs/dir.c      | 1 +
 fs/nfs/nfs4file.c | 2 --
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 23a78a742b619dea8b76ddf28f4f59a1c8a015e2..71df279febf797880ded19e45528c3df4cea2dde 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -66,6 +66,7 @@ const struct file_operations nfs_dir_operations = {
 	.open		= nfs_opendir,
 	.release	= nfs_closedir,
 	.fsync		= nfs_fsync_dir,
+	.setlease	= simple_nosetlease,
 };
 
 const struct address_space_operations nfs_dir_aops = {
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 7317f26892c5782a39660cae87ec1afea24e36c0..7f43e890d3564a000dab9365048a3e17dc96395c 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -431,8 +431,6 @@ void nfs42_ssc_unregister_ops(void)
 static int nfs4_setlease(struct file *file, int arg, struct file_lease **lease,
 			 void **priv)
 {
-	if (!S_ISREG(file_inode(file)->i_mode))
-		return -EINVAL;
 	return nfs4_proc_setlease(file, arg, lease, priv);
 }
 

-- 
2.52.0

On Wed, Jan 07, 2026 at 09:20:09AM -0500, Jeff Layton wrote:
> Checking for S_ISREG() in nfs4_setlease() is incorrect, since that op is
> never called for directories. The right way to deny lease requests on
> directories is to set the ->setlease() operation to simple_nosetlease()
> in the directory file_operations.

This fixes generic/786 on NFSv4.2 for me, so:

Tested-by: Christoph Hellwig <hch@lst.de>