[PATCH v3 01/13] filelock: push the S_ISREG check down to ->setlease handlers

[Jeff Layton <jlayton@kernel.org>]

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 special: It's the only filesystem that supports atomic_open and
allows kernel-internal leases. atomic_open is issued when the VFS
doesn't know the state of the dentry being opened. If the file doesn't
exist, it may be created, in which case the dir lease should be broken.

The existing kernel-internal lease implementation has no provision for
this. Ensure that we don't allow directory leases by default going
forward by explicitly disabling them there.

Reviewed-by: NeilBrown <neil@brown.name>
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 ecaec0fea3a132e7cbb88121e7db7fb504d57d3c..667774cc72a1d49796f531fcb342d2e4878beb85 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -2230,6 +2230,7 @@ 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 04a3f0e2072461b6e2d3d1cd12f2b089d69a7db3..0b16921fb52e602ea2e0c3de39d9d772af98ba7d 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 7f43e890d3564a000dab9365048a3e17dc96395c..7317f26892c5782a39660cae87ec1afea24e36c0 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -431,6 +431,8 @@ 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 4f959f1e08d235071a151c1438c753fcd05099e5..1522c6b61b48c05c93f2bedeab0d35b6d85378e2 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -1149,6 +1149,9 @@ 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))) ||

-- 
2.51.0