NFS: Make clientaddr= optional

For NFSv4 mounts, the clientaddr= mount option has always been
required.  Now we have rpc_localaddr() in the kernel, which was
modeled after the same logic in the mount.nfs command that constructs
the clientaddr= mount option.  If user space doesn't provide a
clientaddr= mount option, the kernel can now construct its own.

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

1 files changed, 15 insertions, 0 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index d038dc5916e5..d30dcbfb6b20 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -1346,6 +1346,7 @@ int nfs4_init_client(struct nfs_client *clp,
                      rpc_authflavor_t authflavour,
                      int noresvport)
 {
+        char buf[INET6_ADDRSTRLEN + 1];
         int error;
 
         if (clp->cl_cons_state == NFS_CS_READY) {
@@ -1361,6 +1362,20 @@ int nfs4_init_client(struct nfs_client *clp,
                                       1, noresvport);
         if (error < 0)
                 goto error;
+
+        /* If no clientaddr= option was specified, find a usable cb address */
+        if (ip_addr == NULL) {
+                struct sockaddr_storage cb_addr;
+                struct sockaddr *sap = (struct sockaddr *)&cb_addr;
+
+                error = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
+                if (error < 0)
+                        goto error;
+                error = rpc_ntop(sap, buf, sizeof(buf));
+                if (error < 0)
+                        goto error;
+                ip_addr = (const char *)buf;
+        }
         strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
 
         error = nfs_idmap_new(clp);