NFS: Mount option parser should detect missing "port="

The meaning of not specifying the "port=" mount option is different
for "-t nfs" and "-t nfs4" mounts.  The default port value for
NFSv2/v3 mounts is 0, but the default for NFSv4 mounts is 2049.

To support "-t nfs -o vers=4", the mount option parser must detect
when "port=" is missing so that the correct default port value can be
set depending on which NFS version is requested.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 2e485677019c..5e686a4d744e 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -49,6 +49,11 @@ struct nfs_clone_mount {
 #define NFS_MAX_SECFLAVORS      (12)
 
 /*
+ * Value used if the user did not specify a port value.
+ */
+#define NFS_UNSPEC_PORT         (-1)
+
+/*
  * In-kernel mount arguments
  */
 struct nfs_parsed_mount_data {
@@ -71,7 +76,7 @@ struct nfs_parsed_mount_data {
                 size_t                  addrlen;
                 char                    *hostname;
                 u32                     version;
-                unsigned short          port;
+                int                     port;
                 unsigned short          protocol;
         } mount_server;
 
@@ -80,7 +85,7 @@ struct nfs_parsed_mount_data {
                 size_t                  addrlen;
                 char                    *hostname;
                 char                    *export_path;
-                unsigned short          port;
+                int                     port;
                 unsigned short          protocol;
         } nfs_server;