[PATCH RFC v2 01/28] filelock: push the S_ISREG check down to ->setlease handlers

Jeff Layton
2025-06-02T14:02:24Z

When nfsd starts requesting directory delegations, setlease handlers may
see requests for leases on directories. Push the !S_ISREG check down
into the non-trivial setlease handlers, so we can selectively enable
them where they're supported.

FUSE is specialr:. It's the only filesystem that supports atomic_open and
allow kernel-internal leases. Ensure that we don't allow directory
leases by default going forward by explicitly disabling them there.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/fuse/dir.c | 1 +
fs/locks.c | 5 +++--
fs/nfs/nfs4file.c | 2 ++
fs/smb/client/cifsfs.c | 3 +++
4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 33b82529cb6e4bffa607e1b20bd09ac489b0667f..c83e61b52e0fff106ef2a3d62efcc3949ccf39e7 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -2218,6 +2218,7 @@ static const struct file_operations fuse_dir_operations = {
.fsync = fuse_dir_fsync,
.unlocked_ioctl = fuse_dir_ioctl,
.compat_ioctl = fuse_dir_compat_ioctl,
+ .setlease = simple_nosetlease,
};

static const struct inode_operations fuse_common_inode_operations = {
diff --git a/fs/locks.c b/fs/locks.c
index 1619cddfa7a4d799f0f84f0bc8f28458d8d280db..a35d033dcaf0b604b73395260562af08f7711c12 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1929,6 +1929,9 @@ static int generic_delete_lease(struct file *filp, void *owner)
int generic_setlease(struct file *filp, int arg, struct file_lease **flp,
void **priv)
{
+ if (!S_ISREG(file_inode(filp)->i_mode))
+ return -EINVAL;
+
switch (arg) {
case F_UNLCK:
return generic_delete_lease(filp, *priv);
@@ -2018,8 +2021,6 @@ vfs_setlease(struct file *filp, int arg, struct file_lease **lease, void **priv)

if ((!vfsuid_eq_kuid(vfsuid, current_fsuid())) && !capable(CAP_LEASE))
return -EACCES;
- if (!S_ISREG(inode->i_mode))
- return -EINVAL;
error = security_file_lock(filp, arg);
if (error)
return error;
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 1cd9652f3c280358209f22503ea573a906a6194e..b7630a437ad22fbfb658086953b25b9ae6b4f057 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -442,6 +442,8 @@ 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);
}

diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index fb04e263611cadaea210f5c1d90c05bea37fb496..991583b0b77e480c002974b410f06853740e4b1b 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -1094,6 +1094,9 @@ cifs_setlease(struct file *file, int arg, struct file_lease **lease, void **priv
struct inode *inode = file_inode(file);
struct cifsFileInfo *cfile = file->private_data;

+ if (!S_ISREG(inode->i_mode))
+ return -EINVAL;
+
/* Check if file is oplocked if this is request for new lease */
if (arg == F_UNLCK ||
((arg == F_RDLCK) && CIFS_CACHE_READ(CIFS_I(inode))) ||

--
2.49.0