nfs: hornor timeo and retrans option when mounting NFSv3

Mounting NFSv3 uses default timeout parameters specified by underlying
sunrpc transport, and mount options like 'timeo' and 'retrans', unlike
NFSv4, are not honored.

But sometimes we want to set non-default timeout value when mounting
NFSv3, so pass 'timeo' and 'retrans' to nfs_mount() and fill the
'timeout' field of struct rpc_create_args before creating RPC
connection. This is also consistent with NFSv4 behavior.

Note that this only sets the timeout value of rpc connection to mountd,
but the timeout of rpcbind connection should be set as well. A later
patch will fix the rpcbind part.
Signed-off-by: NEryu Guan <eguan@linux.alibaba.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/internal.h

@@ -180,7 +180,7 @@ struct nfs_mount_request {
 	struct net		*net;
 };
 
-extern int nfs_mount(struct nfs_mount_request *info);
+extern int nfs_mount(struct nfs_mount_request *info, int timeo, int retrans);
 extern void nfs_umount(const struct nfs_mount_request *info);
 
 /* client.c */

fs/nfs/mount_clnt.c

@@ -136,14 +136,16 @@ struct mnt_fhstatus {
 /**
  * nfs_mount - Obtain an NFS file handle for the given host and path
  * @info: pointer to mount request arguments
+ * @timeo: deciseconds the mount waits for a response before it retries
+ * @retrans: number of times the mount retries a request
  *
- * Uses default timeout parameters specified by underlying transport. On
- * successful return, the auth_flavs list and auth_flav_len will be populated
- * with the list from the server or a faked-up list if the server didn't
- * provide one.
+ * Uses timeout parameters specified by caller. On successful return, the
+ * auth_flavs list and auth_flav_len will be populated with the list from the
+ * server or a faked-up list if the server didn't provide one.
  */
-int nfs_mount(struct nfs_mount_request *info)
+int nfs_mount(struct nfs_mount_request *info, int timeo, int retrans)
 {
+	struct rpc_timeout mnt_timeout;
 	struct mountres	result = {
 		.fh		= info->fh,
 		.auth_count	= info->auth_flav_len,
@@ -158,6 +160,7 @@ int nfs_mount(struct nfs_mount_request *info)
 		.protocol	= info->protocol,
 		.address	= info->sap,
 		.addrsize	= info->salen,
+		.timeout	= &mnt_timeout,
 		.servername	= info->hostname,
 		.program	= &mnt_program,
 		.version	= info->version,
@@ -177,6 +180,7 @@ int nfs_mount(struct nfs_mount_request *info)
 	if (info->noresvport)
 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 
+	nfs_init_timeout_values(&mnt_timeout, info->protocol, timeo, retrans);
 	mnt_clnt = rpc_create(&args);
 	if (IS_ERR(mnt_clnt))
 		goto out_clnt_err;

fs/nfs/super.c

@@ -867,7 +867,7 @@ static int nfs_request_mount(struct fs_context *fc,
 	 * Now ask the mount server to map our export path
 	 * to a file handle.
 	 */
-	status = nfs_mount(&request);
+	status = nfs_mount(&request, ctx->timeo, ctx->retrans);
 	if (status != 0) {
 		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
 				request.hostname, status);