NFSv4: Send unmapped uid/gids to the server when using auth_sys

The new behaviour is enabled using the new module parameter
'nfs4_disable_idmapping'.

Note that if the server rejects an unmapped uid or gid, then
the client will automatically switch back to using the idmapper.

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

1 files changed, 16 insertions, 0 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 6dd50ac5b545..139be9647d80 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -82,6 +82,11 @@ retry:
 #endif /* CONFIG_NFS_V4 */
 
 /*
+ * Turn off NFSv4 uid/gid mapping when using AUTH_SYS
+ */
+static int nfs4_disable_idmapping = 0;
+
+/*
  * RPC cruft for NFS
  */
 static struct rpc_version *nfs_version[5] = {
@@ -1567,6 +1572,13 @@ static int nfs4_init_server(struct nfs_server *server,
         if (error < 0)
                 goto error;
 
+        /*
+         * Don't use NFS uid/gid mapping if we're using AUTH_SYS or lower
+         * authentication.
+         */
+        if (nfs4_disable_idmapping && data->auth_flavors[0] == RPC_AUTH_UNIX)
+                server->caps |= NFS_CAP_UIDGID_NOMAP;
+
         if (data->rsize)
                 server->rsize = nfs_block_size(data->rsize, NULL);
         if (data->wsize)
@@ -1984,3 +1996,7 @@ void nfs_fs_proc_exit(void)
 }
 
 #endif /* CONFIG_PROC_FS */
+
+module_param(nfs4_disable_idmapping, bool, 0644);
+MODULE_PARM_DESC(nfs4_disable_idmapping,
+                "Turn off NFSv4 idmapping when using 'sec=sys'");