NFS: Remake nfsroot_mount as a permanent part of NFS client

In preparation for supporting NFSv2 and NFSv3 mount option handling in the
kernel NFS client, convert mount_clnt.c to be a permanent part of the NFS
client, instead of built only when CONFIG_ROOT_NFS is enabled.

In addition, we also replace the "struct sockaddr_in *" argument with
something more generic, to help support IPv6 at some later point.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/Makefile

@@ -6,8 +6,8 @@ obj-$(CONFIG_NFS_FS) += nfs.o
 
 nfs-y 			:= client.o dir.o file.o getroot.o inode.o super.o nfs2xdr.o \
 			   pagelist.o proc.o read.o symlink.o unlink.o \
-			   write.o namespace.o
-nfs-$(CONFIG_ROOT_NFS)	+= nfsroot.o mount_clnt.o      
+			   write.o namespace.o mount_clnt.o
+nfs-$(CONFIG_ROOT_NFS)	+= nfsroot.o
 nfs-$(CONFIG_NFS_V3)	+= nfs3proc.o nfs3xdr.o
 nfs-$(CONFIG_NFS_V3_ACL)	+= nfs3acl.o
 nfs-$(CONFIG_NFS_V4)	+= nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \

fs/nfs/mount_clnt.c

@@ -18,7 +18,7 @@
 #include <linux/nfs_fs.h>
 
 #ifdef RPC_DEBUG
-# define NFSDBG_FACILITY	NFSDBG_ROOT
+# define NFSDBG_FACILITY	NFSDBG_MOUNT
 #endif
 
 /*
@@ -28,7 +28,6 @@
 #define MOUNT_UMNT		3
  */
 
-static struct rpc_clnt *	mnt_create(struct sockaddr_in *, int, int);
 static struct rpc_program	mnt_program;
 
 struct mnt_fhstatus {
@@ -36,14 +35,21 @@ struct mnt_fhstatus {
 	struct nfs_fh *		fh;
 };
 
-/*
- * Obtain an NFS file handle for the given host and path
+/**
+ * nfs_mount - Obtain an NFS file handle for the given host and path
+ * @addr: pointer to server's address
+ * @len: size of server's address
+ * @hostname: name of server host, or NULL
+ * @path: pointer to string containing export path to mount
+ * @version: mount version to use for this request
+ * @protocol: transport protocol to use for thie request
+ * @fh: pointer to location to place returned file handle
+ *
+ * Uses default timeout parameters specified by underlying transport.
  */
-int
-nfsroot_mount(struct sockaddr_in *addr, char *path, struct nfs_fh *fh,
-		int version, int protocol)
+int nfs_mount(struct sockaddr *addr, size_t len, char *hostname, char *path,
+	      int version, int protocol, struct nfs_fh *fh)
 {
-	struct rpc_clnt		*mnt_clnt;
 	struct mnt_fhstatus	result = {
 		.fh		= fh
 	};
@@ -51,12 +57,23 @@ nfsroot_mount(struct sockaddr_in *addr, char *path, struct nfs_fh *fh,
 		.rpc_argp	= path,
 		.rpc_resp	= &result,
 	};
+	struct rpc_create_args args = {
+		.protocol	= protocol,
+		.address	= addr,
+		.addrsize	= len,
+		.servername	= hostname,
+		.program	= &mnt_program,
+		.version	= version,
+		.authflavor	= RPC_AUTH_UNIX,
+		.flags		= RPC_CLNT_CREATE_INTR,
+	};
+	struct rpc_clnt		*mnt_clnt;
 	int			status;
 
-	dprintk("NFS:      nfs_mount(%08x:%s)\n",
-			(unsigned)ntohl(addr->sin_addr.s_addr), path);
+	dprintk("NFS: sending MNT request for %s:%s\n",
+		(hostname ? hostname : "server"), path);
 
-	mnt_clnt = mnt_create(addr, version, protocol);
+	mnt_clnt = rpc_create(&args);
 	if (IS_ERR(mnt_clnt))
 		return PTR_ERR(mnt_clnt);
 
@@ -70,22 +87,6 @@ nfsroot_mount(struct sockaddr_in *addr, char *path, struct nfs_fh *fh,
 	return status < 0? status : (result.status? -EACCES : 0);
 }
 
-static struct rpc_clnt *mnt_create(struct sockaddr_in *srvaddr, int version,
-				   int protocol)
-{
-	struct rpc_create_args args = {
-		.protocol	= protocol,
-		.address	= (struct sockaddr *)srvaddr,
-		.addrsize	= sizeof(*srvaddr),
-		.program	= &mnt_program,
-		.version	= version,
-		.authflavor	= RPC_AUTH_UNIX,
-		.flags		= RPC_CLNT_CREATE_INTR,
-	};
-
-	return rpc_create(&args);
-}
-
 /*
  * XDR encode/decode functions for MOUNT
  */

fs/nfs/nfsroot.c

@@ -496,7 +496,8 @@ static int __init root_nfs_get_handle(void)
 					NFS_MNT3_VERSION : NFS_MNT_VERSION;
 
 	set_sockaddr(&sin, servaddr, htons(mount_port));
-	status = nfsroot_mount(&sin, nfs_path, &fh, version, protocol);
+	status = nfs_mount((struct sockaddr *) &sin, sizeof(sin), NULL,
+			   nfs_path, version, protocol, &fh);
 	if (status < 0)
 		printk(KERN_ERR "Root-NFS: Server returned error %d "
 				"while mounting %s\n", status, nfs_path);

include/linux/nfs_fs.h

@@ -494,10 +494,9 @@ static inline void nfs3_forget_cached_acls(struct inode *inode)
 
 /*
  * linux/fs/mount_clnt.c
- * (Used only by nfsroot module)
  */
-extern int  nfsroot_mount(struct sockaddr_in *, char *, struct nfs_fh *,
-		int, int);
+extern int  nfs_mount(struct sockaddr *, size_t, char *, char *,
+		      int, int, struct nfs_fh *);
 
 /*
  * inline functions