1 files changed, 21 insertions, 1 deletions

diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 074ac7131459..9301040b553d 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -464,6 +464,11 @@ static bool nfs4_match_client_owner_id(const struct nfs_client *clp1,
 	return strcmp(clp1->cl_owner_id, clp2->cl_owner_id) == 0;
 }
 
+static bool nfs4_same_verifier(nfs4_verifier *v1, nfs4_verifier *v2)
+{
+	return memcmp(v1->data, v2->data, sizeof(v1->data)) == 0;
+}
+
 /**
  * nfs40_walk_client_list - Find server that recognizes a client ID
  *
@@ -521,7 +526,21 @@ int nfs40_walk_client_list(struct nfs_client *new,
 
 		if (!nfs4_match_client_owner_id(pos, new))
 			continue;
-
+		/*
+		 * We just sent a new SETCLIENTID, which should have
+		 * caused the server to return a new cl_confirm.  So if
+		 * cl_confirm is the same, then this is a different
+		 * server that just returned the same cl_confirm by
+		 * coincidence:
+		 */
+		if ((new != pos) && nfs4_same_verifier(&pos->cl_confirm,
+						       &new->cl_confirm))
+			continue;
+		/*
+		 * But if the cl_confirm's are different, then the only
+		 * way that a SETCLIENTID_CONFIRM to pos can succeed is
+		 * if new and pos point to the same server:
+		 */
 		atomic_inc(&pos->cl_count);
 		spin_unlock(&nn->nfs_client_lock);
 
@@ -534,6 +553,7 @@ int nfs40_walk_client_list(struct nfs_client *new,
 			break;
 		case 0:
 			nfs4_swap_callback_idents(pos, new);
+			pos->cl_confirm = new->cl_confirm;
 
 			prev = NULL;
 			*result = pos;