[PATCH 1/6] nfs: properly disallow delegation requests on directories

Jeff Layton
2026-01-07T14:20:35Z

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