ctdb-tools/ctdb: Detach databases only if all nodes disallow client access

This makes sure that AllowClientDBAttach is set to 0 before detaching any
databases.

If someone enables the tunable between checking of tunable and actual
detaching of databases, then they deserve what they get. :-)

Signed-off-by: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Michael Adam <obnox@samba.org>

2 files changed, 68 insertions, 0 deletions

diff --git a/ctdb/doc/ctdb.1.xml b/ctdb/doc/ctdb.1.xml
index 95a67dbeeda..433e65018af 100644
--- a/ctdb/doc/ctdb.1.xml
+++ b/ctdb/doc/ctdb.1.xml
@@ -1576,6 +1576,10 @@ HEALTH: NO-HEALTHY-NODES - ERROR - Backup of corrupted TDB in '/var/ctdb/persist
 	the cluster.  This command should only be used when none of the
 	specified database(s) are in use.
       </para>
+      <para>
+	All nodes should be active and tunable AllowClientDBAccess should
+	be disabled on all nodes before detaching databases.
+      </para>
     </refsect2>
 
     <refsect2>
diff --git a/ctdb/tools/ctdb.c b/ctdb/tools/ctdb.c
index 74cf321fa26..4afb3e7af7b 100644
--- a/ctdb/tools/ctdb.c
+++ b/ctdb/tools/ctdb.c
@@ -5194,6 +5194,9 @@ static int control_detach(struct ctdb_context *ctdb, int argc,
 	uint32_t db_id;
 	uint8_t flags;
 	int ret, i, status = 0;
+	struct ctdb_node_map *nodemap = NULL;
+	TALLOC_CTX *tmp_ctx = talloc_new(ctdb);
+	uint32_t recmode;
 
 	if (argc < 1) {
 		usage();
@@ -5201,6 +5204,67 @@ static int control_detach(struct ctdb_context *ctdb, int argc,
 
 	assert_single_node_only();
 
+	ret = ctdb_ctrl_getrecmode(ctdb, tmp_ctx, TIMELIMIT(), options.pnn,
+				    &recmode);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR, ("Database cannot be detached "
+				  "when recovery is active\n"));
+		talloc_free(tmp_ctx);
+		return -1;
+	}
+
+	ret = ctdb_ctrl_getnodemap(ctdb, TIMELIMIT(), options.pnn, tmp_ctx,
+				   &nodemap);
+	if (ret != 0) {
+		DEBUG(DEBUG_ERR, ("Unable to get nodemap from node %u\n",
+				  options.pnn));
+		talloc_free(tmp_ctx);
+		return -1;
+	}
+
+	for (i=0; i<nodemap->num; i++) {
+		uint32_t value;
+
+		if (nodemap->nodes[i].flags & NODE_FLAGS_DISCONNECTED) {
+			continue;
+		}
+
+		if (nodemap->nodes[i].flags & NODE_FLAGS_DELETED) {
+			continue;
+		}
+
+		if (nodemap->nodes[i].flags & NODE_FLAGS_INACTIVE) {
+			DEBUG(DEBUG_ERR, ("Database cannot be detached on "
+					  "inactive (stopped or banned) node "
+					  "%u\n", nodemap->nodes[i].pnn));
+			talloc_free(tmp_ctx);
+			return -1;
+		}
+
+		ret = ctdb_ctrl_get_tunable(ctdb, TIMELIMIT(),
+					    nodemap->nodes[i].pnn,
+					    "AllowClientDBAttach",
+					    &value);
+		if (ret != 0) {
+			DEBUG(DEBUG_ERR, ("Unable to get tunable "
+					  "AllowClientDBAttach from node %u\n",
+					   nodemap->nodes[i].pnn));
+			talloc_free(tmp_ctx);
+			return -1;
+		}
+
+		if (value == 1) {
+			DEBUG(DEBUG_ERR, ("Database access is still active on "
+					  "node %u. Set AllowClientDBAttach=0 "
+					  "on all nodes.\n",
+					  nodemap->nodes[i].pnn));
+			talloc_free(tmp_ctx);
+			return -1;
+		}
+	}
+
+	talloc_free(tmp_ctx);
+
 	for (i=0; i<argc; i++) {
 		if (!db_exists(ctdb, argv[i], &db_id, NULL, &flags)) {
 			continue;