nfs: explicitly reject LOCK_MAND flock() requests
We have no mechanism to emulate LOCK_MAND locks on NFSv4, so explicitly
return -EINVAL if someone requests it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 1557978..b039a17 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -834,6 +834,15 @@
if (!(fl->fl_flags & FL_FLOCK))
return -ENOLCK;
+ /*
+ * The NFSv4 protocol doesn't support LOCK_MAND, which is not part of
+ * any standard. In principle we might be able to support LOCK_MAND
+ * on NFSv2/3 since NLMv3/4 support DOS share modes, but for now the
+ * NFS code is not set up for it.
+ */
+ if (fl->fl_type & LOCK_MAND)
+ return -EINVAL;
+
if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
is_local = 1;