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>

2 files changed, 36 insertions, 28 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;
 
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index f3a95df4b95f..05544336f7de 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -747,6 +747,21 @@ static int nfs_verify_server_address(struct sockaddr *addr)
 }
 
 /*
+ * Select between a default port value and a user-specified port value.
+ * If a zero value is set, then autobind will be used.
+ */
+static void nfs_set_default_port(struct sockaddr *sap, const int parsed_port,
+                                 const unsigned short default_port)
+{
+        unsigned short port = default_port;
+
+        if (parsed_port != NFS_UNSPEC_PORT)
+                port = parsed_port;
+
+        rpc_set_port(sap, port);
+}
+
+/*
  * Sanity check the NFS transport protocol.
  *
  */
@@ -1415,11 +1430,7 @@ static int nfs_try_mount(struct nfs_parsed_mount_data *args,
                 args->mount_server.addrlen = args->nfs_server.addrlen;
         }
         request.salen = args->mount_server.addrlen;
-
-        /*
-         * autobind will be used if mount_server.port == 0
-         */
-        rpc_set_port(request.sap, args->mount_server.port);
+        nfs_set_default_port(request.sap, args->mount_server.port, 0);
 
         /*
          * Now ask the mount server to map our export path
@@ -1597,6 +1608,7 @@ static int nfs_validate_mount_data(void *options,
                                    const char *dev_name)
 {
         struct nfs_mount_data *data = (struct nfs_mount_data *)options;
+        struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
 
         if (data == NULL)
                 goto out_no_data;
@@ -1608,8 +1620,8 @@ static int nfs_validate_mount_data(void *options,
         args->acregmax          = NFS_DEF_ACREGMAX;
         args->acdirmin          = NFS_DEF_ACDIRMIN;
         args->acdirmax          = NFS_DEF_ACDIRMAX;
-        args->mount_server.port = 0;    /* autobind unless user sets port */
-        args->nfs_server.port   = 0;    /* autobind unless user sets port */
+        args->mount_server.port = NFS_UNSPEC_PORT;
+        args->nfs_server.port   = NFS_UNSPEC_PORT;
         args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
         args->auth_flavors[0]   = RPC_AUTH_UNIX;
         args->auth_flavor_len   = 1;
@@ -1657,11 +1669,9 @@ static int nfs_validate_mount_data(void *options,
                 args->acdirmin          = data->acdirmin;
                 args->acdirmax          = data->acdirmax;
 
-                memcpy(&args->nfs_server.address, &data->addr,
-                       sizeof(data->addr));
+                memcpy(sap, &data->addr, sizeof(data->addr));
                 args->nfs_server.addrlen = sizeof(data->addr);
-                if (!nfs_verify_server_address((struct sockaddr *)
-                                                &args->nfs_server.address))
+                if (!nfs_verify_server_address(sap))
                         goto out_no_address;
 
                 if (!(data->flags & NFS_MOUNT_TCP))
@@ -1709,12 +1719,10 @@ static int nfs_validate_mount_data(void *options,
                 if (nfs_parse_mount_options((char *)options, args) == 0)
                         return -EINVAL;
 
-                if (!nfs_verify_server_address((struct sockaddr *)
-                                                &args->nfs_server.address))
+                if (!nfs_verify_server_address(sap))
                         goto out_no_address;
 
-                rpc_set_port((struct sockaddr *)&args->nfs_server.address,
-                                args->nfs_server.port);
+                nfs_set_default_port(sap, args->nfs_server.port, 0);
 
                 nfs_set_mount_transport_protocol(args);
 
@@ -2261,7 +2269,7 @@ static int nfs4_validate_mount_data(void *options,
                                     struct nfs_parsed_mount_data *args,
                                     const char *dev_name)
 {
-        struct sockaddr_in *ap;
+        struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
         struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
         char *c;
 
@@ -2274,23 +2282,21 @@ static int nfs4_validate_mount_data(void *options,
         args->acregmax          = NFS_DEF_ACREGMAX;
         args->acdirmin          = NFS_DEF_ACDIRMIN;
         args->acdirmax          = NFS_DEF_ACDIRMAX;
-        args->nfs_server.port   = NFS_PORT; /* 2049 unless user set port= */
+        args->nfs_server.port   = NFS_UNSPEC_PORT;
         args->auth_flavors[0]   = RPC_AUTH_UNIX;
         args->auth_flavor_len   = 1;
         args->minorversion      = 0;
 
         switch (data->version) {
         case 1:
-                ap = (struct sockaddr_in *)&args->nfs_server.address;
                 if (data->host_addrlen > sizeof(args->nfs_server.address))
                         goto out_no_address;
                 if (data->host_addrlen == 0)
                         goto out_no_address;
                 args->nfs_server.addrlen = data->host_addrlen;
-                if (copy_from_user(ap, data->host_addr, data->host_addrlen))
+                if (copy_from_user(sap, data->host_addr, data->host_addrlen))
                         return -EFAULT;
-                if (!nfs_verify_server_address((struct sockaddr *)
-                                                &args->nfs_server.address))
+                if (!nfs_verify_server_address(sap))
                         goto out_no_address;
 
                 if (data->auth_flavourlen) {
@@ -2342,12 +2348,9 @@ static int nfs4_validate_mount_data(void *options,
                 if (nfs_parse_mount_options((char *)options, args) == 0)
                         return -EINVAL;
 
-                if (!nfs_verify_server_address((struct sockaddr *)
-                                                &args->nfs_server.address))
+                if (!nfs_verify_server_address(sap))
                         return -EINVAL;
-
-                rpc_set_port((struct sockaddr *)&args->nfs_server.address,
-                                args->nfs_server.port);
+                nfs_set_default_port(sap, args->nfs_server.port, NFS_PORT);
 
                 nfs_validate_transport_protocol(args);