NFS: Save the value of the "port=" mount option

During a remount based on the mount options displayed in /proc/mounts, we
want to preserve the original behavior of the mount request.  Let's save
the original setting of the "port=" mount option in the mount's nfs_server
structure.

This allows us to simplify the default behavior of port setting for NFSv4
mounts: by default, NFSv2/3 mounts first try an RPC bind to determine the
NFS server's port, unless the user specified the "port=" mount option;
Users can force the client to skip the RPC bind by explicitly specifying
"port=<value>".

NFSv4, by contrast, assumes the NFS server port is 2049 and skips the RPC
bind, unless the user specifies "port=".  Users can force an RPC bind for
NFSv4 by explicitly specifying "port=0".

I added a couple of extra comments to clarify this behavior.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 6 insertions, 31 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 53a67c6d4d2a..3c6f53aa7317 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -685,7 +685,6 @@ static int nfs_parse_mount_options(char *raw,
                                    struct nfs_parsed_mount_data *mnt)
 {
         char *p, *string, *secdata;
-        unsigned short port = 0;
         int rc;
 
         if (!raw) {
@@ -800,7 +799,7 @@ static int nfs_parse_mount_options(char *raw,
                                 return 0;
                         if (option < 0 || option > 65535)
                                 return 0;
-                        port = option;
+                        mnt->nfs_server.port = option;
                         break;
                 case Opt_rsize:
                         if (match_int(args, &mnt->rsize))
@@ -1050,7 +1049,8 @@ static int nfs_parse_mount_options(char *raw,
                 }
         }
 
-        nfs_set_port((struct sockaddr *)&mnt->nfs_server.address, port);
+        nfs_set_port((struct sockaddr *)&mnt->nfs_server.address,
+                                mnt->nfs_server.port);
 
         return 1;
 
@@ -1171,7 +1171,9 @@ static int nfs_validate_mount_data(void *options,
         args->acregmax          = 60;
         args->acdirmin          = 30;
         args->acdirmax          = 60;
+        args->mount_server.port = 0;    /* autobind unless user sets port */
         args->mount_server.protocol = XPRT_TRANSPORT_UDP;
+        args->nfs_server.port   = 0;    /* autobind unless user sets port */
         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 
         switch (data->version) {
@@ -1708,28 +1710,6 @@ static void nfs4_fill_super(struct super_block *sb)
 }
 
 /*
- * If the user didn't specify a port, set the port number to
- * the NFS version 4 default port.
- */
-static void nfs4_default_port(struct sockaddr *sap)
-{
-        switch (sap->sa_family) {
-        case AF_INET: {
-                struct sockaddr_in *ap = (struct sockaddr_in *)sap;
-                if (ap->sin_port == 0)
-                        ap->sin_port = htons(NFS_PORT);
-                break;
-        }
-        case AF_INET6: {
-                struct sockaddr_in6 *ap = (struct sockaddr_in6 *)sap;
-                if (ap->sin6_port == 0)
-                        ap->sin6_port = htons(NFS_PORT);
-                break;
-        }
-        }
-}
-
-/*
  * Validate NFSv4 mount options
  */
 static int nfs4_validate_mount_data(void *options,
@@ -1753,6 +1733,7 @@ static int nfs4_validate_mount_data(void *options,
         args->acregmax          = 60;
         args->acdirmin          = 30;
         args->acdirmax          = 60;
+        args->nfs_server.port   = NFS_PORT; /* 2049 unless user set port= */
         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
 
         switch (data->version) {
@@ -1769,9 +1750,6 @@ static int nfs4_validate_mount_data(void *options,
                                                 &args->nfs_server.address))
                         goto out_no_address;
 
-                nfs4_default_port((struct sockaddr *)
-                                  &args->nfs_server.address);
-
                 switch (data->auth_flavourlen) {
                 case 0:
                         args->auth_flavors[0] = RPC_AUTH_UNIX;
@@ -1829,9 +1807,6 @@ static int nfs4_validate_mount_data(void *options,
                                                 &args->nfs_server.address))
                         return -EINVAL;
 
-                nfs4_default_port((struct sockaddr *)
-                                  &args->nfs_server.address);
-
                 switch (args->auth_flavor_len) {
                 case 0:
                         args->auth_flavors[0] = RPC_AUTH_UNIX;