NFS: Added support to turn off the NFSv3 READDIRPLUS RPC.

READDIRPLUS can be a performance hindrance when the client is working with
large directories. In addition, some servers still have bugs in their
implementations (e.g. Tru64 returns wrong values for the fsid).

Add a mount flag to enable users to turn it off at mount time following the
implementation in Apple's NFS client.

Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 3 insertions, 1 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 2190e6c2792e..5bd03b97002e 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -618,7 +618,8 @@ static int nfs_init_server(struct nfs_server *server, const struct nfs_mount_dat
         if (clp->cl_nfsversion == 3) {
                 if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
                         server->namelen = NFS3_MAXNAMLEN;
-                server->caps |= NFS_CAP_READDIRPLUS;
+                if (!(data->flags & NFS_MOUNT_NORDIRPLUS))
+                        server->caps |= NFS_CAP_READDIRPLUS;
         } else {
                 if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
                         server->namelen = NFS2_MAXNAMLEN;
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 719464a04dda..ca20d3cc2609 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -290,6 +290,7 @@ static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
                 { NFS_MOUNT_NOAC, ",noac", "" },
                 { NFS_MOUNT_NONLM, ",nolock", "" },
                 { NFS_MOUNT_NOACL, ",noacl", "" },
+                { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
                 { 0, NULL, NULL }
         };
         const struct proc_nfs_info *nfs_infop;