NFS4: Avoid migration loops

If a server returns itself as a location while migrating, the client may
end up getting stuck attempting to migrate twice to the same server.  Catch
this by checking if the nfs_client found is the same as the existing
client.  For the other two callers to nfs4_set_client, the nfs_client will
always be ERR_PTR(-EINVAL).

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 8d7d08d4f95f17e09d53bda53da364ef02ea05b8..cd3b7cfdde16ae0e16cc17fbc9389ffc60eb511a 100644 (file)
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -817,6 +817,11 @@ static int nfs4_set_client(struct nfs_server *server,
                goto error;
        }
 
+       if (server->nfs_client == clp) {
+               error = -ELOOP;
+               goto error;
+       }
+
        /*
         * Query for the lease time on clientid setup or renewal
         *