NFSv4.1: add MDS mount DS only check

The DS only role cannot be used to mount.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 280d41f64a57..d5c5bdfa4231 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -1453,6 +1453,10 @@ static int nfs4_server_common_setup(struct nfs_server *server,
         BUG_ON(!server->nfs_client->rpc_ops);
         BUG_ON(!server->nfs_client->rpc_ops->file_inode_ops);
 
+        /* data servers support only a subset of NFSv4.1 */
+        if (is_ds_only_client(server->nfs_client))
+                return -EPROTONOSUPPORT;
+
         fattr = nfs_alloc_fattr();
         if (fattr == NULL)
                 return -ENOMEM;