[Ocfs2-devel] [PATCH 1/7] Add dlm operations placeholders

[Goldwyn Rodrigues <rgoldwyn@suse.de>]

Try locking with the new DLM semantics with the dlm operations.
If operation fails with EOPNOTSUPP, try the old semantics.
This would ensure that filesystems are mounted for those who
are upgrading the kernel but not the tools.
Users using old tools will be presented with a notice message
to upgrade the tools.

recover_prep() is called when DLM understands a node is down.
recover_slot() is called once all nodes have acknowledged recover_prep and
recovery can begin.
recover_done() is called once the recovery is complete. It returns the
new membership.
---
 fs/ocfs2/stack_user.c | 70 +++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 51 insertions(+), 19 deletions(-)

diff --git a/fs/ocfs2/stack_user.c b/fs/ocfs2/stack_user.c
index 286edf1..b44490b 100644
--- a/fs/ocfs2/stack_user.c
+++ b/fs/ocfs2/stack_user.c
@@ -799,14 +799,63 @@ static int fs_protocol_compare(struct ocfs2_protocol_version *existing,
 	return 0;
 }
 
+static void user_recover_prep(void *arg)
+{
+}
+
+static void user_recover_slot(void *arg, struct dlm_slot *slot)
+{
+}
+
+static void user_recover_done(void *arg, struct dlm_slot *slots,
+			      int num_slots, int our_slot,
+			      uint32_t generation)
+{
+}
+
+const struct dlm_lockspace_ops ocfs2_ls_ops = {
+	.recover_prep = user_recover_prep,
+	.recover_slot = user_recover_slot,
+	.recover_done = user_recover_done,
+};
+
+static int user_cluster_disconnect(struct ocfs2_cluster_connection *conn)
+{
+	dlm_release_lockspace(conn->cc_lockspace, 2);
+	conn->cc_lockspace = NULL;
+	ocfs2_live_connection_drop(conn->cc_private);
+	conn->cc_private = NULL;
+	return 0;
+}
+
 static int user_cluster_connect(struct ocfs2_cluster_connection *conn)
 {
 	dlm_lockspace_t *fsdlm;
 	struct ocfs2_live_connection *uninitialized_var(control);
-	int rc = 0;
+	int rc = 0, ops_rv;
 
 	BUG_ON(conn == NULL);
 
+	rc = dlm_new_lockspace(conn->cc_name, NULL, DLM_LSFL_FS, DLM_LVB_LEN,
+				&ocfs2_ls_ops, conn, &ops_rv, &fsdlm);
+
+	if (rc)
+		goto out;
+
+	if (!ops_rv) {
+		/* DLM lockspace creation with newer new_lockspace successful */
+		goto out;
+	} else if (ops_rv != -EOPNOTSUPP) {
+		rc = ops_rv;
+		goto out;
+	}
+
+	conn->cc_lockspace = fsdlm;
+
+	printk(KERN_NOTICE "ocfs2: You seem to be using an older version "
+			"of dlm_controld and/or ocfs2-tools. Please consider "
+			"upgrading.\n");
+
 	rc = ocfs2_live_connection_new(conn, &control);
 	if (rc)
 		goto out;
@@ -823,32 +872,15 @@ static int user_cluster_connect(struct ocfs2_cluster_connection *conn)
 		       conn->cc_version.pv_major, conn->cc_version.pv_minor,
 		       running_proto.pv_major, running_proto.pv_minor);
 		rc = -EPROTO;
-		ocfs2_live_connection_drop(control);
-		goto out;
-	}
-
-	rc = dlm_new_lockspace(conn->cc_name, NULL, DLM_LSFL_FS, DLM_LVB_LEN,
-			       NULL, NULL, NULL, &fsdlm);
-	if (rc) {
-		ocfs2_live_connection_drop(control);
+		user_cluster_disconnect(conn);
 		goto out;
 	}
 
 	conn->cc_private = control;
-	conn->cc_lockspace = fsdlm;
 out:
 	return rc;
 }
 
-static int user_cluster_disconnect(struct ocfs2_cluster_connection *conn)
-{
-	dlm_release_lockspace(conn->cc_lockspace, 2);
-	conn->cc_lockspace = NULL;
-	ocfs2_live_connection_drop(conn->cc_private);
-	conn->cc_private = NULL;
-	return 0;
-}
-
 static int user_cluster_this_node(unsigned int *this_node)
 {
 	int rc;
-- 
1.8.1.4


-- 
Goldwyn