[SCM] CTDB repository - branch master updated - ctdb-1.0.95-2-g70e7781

[Ronnie Sahlberg]

The branch, master has been updated
       via  70e7781df1f118a0e2632a9c634f3fd388fa6c8c (commit)
      from  346fa055f4106497b87df97da5ebd6e51fa1ef8c (commit)

http://gitweb.samba.org/?p=sahlberg/ctdb.git;a=shortlog;h=master


- Log -----------------------------------------------------------------
commit 70e7781df1f118a0e2632a9c634f3fd388fa6c8c
Author: Ronnie Sahlberg <ronniesahlberg at gmail.com>
Date:   Wed Oct 14 08:17:49 2009 +1100

    Port Volkers deadlock avoidance patch to HEAD.
    This patch ensures that we lock all non-notify related databases first and
    then the notify databases to avoiud a deadlock where samba needs to lock records on two databases at once (and notify being the second database).
    
    Newer versions of samba would instead use the set-db-prio control to set this explicitely on a database per database basis instead of relying on  hardcoded database names. This patch will be reverted in the future when all updated versions of samba has been pushed out.

-----------------------------------------------------------------------

Summary of changes:
 server/ctdb_freeze.c  |   21 +++++++++++++++++++++
 server/ctdb_recover.c |   20 ++++++++++++++++++++
 2 files changed, 41 insertions(+), 0 deletions(-)


Changeset truncated at 500 lines:

diff --git a/server/ctdb_freeze.c b/server/ctdb_freeze.c
index da7272f..a2b765b 100644
--- a/server/ctdb_freeze.c
+++ b/server/ctdb_freeze.c
@@ -33,10 +33,31 @@
 static int ctdb_lock_all_databases(struct ctdb_context *ctdb, uint32_t priority)
 {
 	struct ctdb_db_context *ctdb_db;
+	/* REMOVE later */
+	/* This double loop is for backward compatibility and deadlock
+	   avoidance for old samba versions that not yet support
+	   the set prio call.
+	   This code shall be removed later
+	*/
 	for (ctdb_db=ctdb->db_list;ctdb_db;ctdb_db=ctdb_db->next) {
 		if (ctdb_db->priority != priority) {
 			continue;
 		}
+		if (strstr(ctdb_db->db_name, "notify") != NULL) {
+			continue;
+		}
+		DEBUG(DEBUG_INFO,("locking database 0x%08x priority:%u %s\n", ctdb_db->db_id, ctdb_db->priority, ctdb_db->db_name));
+		if (tdb_lockall(ctdb_db->ltdb->tdb) != 0) {
+			return -1;
+		}
+	}
+	for (ctdb_db=ctdb->db_list;ctdb_db;ctdb_db=ctdb_db->next) {
+		if (ctdb_db->priority != priority) {
+			continue;
+		}
+		if (strstr(ctdb_db->db_name, "notify") == NULL) {
+			continue;
+		}
 		DEBUG(DEBUG_INFO,("locking database 0x%08x priority:%u %s\n", ctdb_db->db_id, ctdb_db->priority, ctdb_db->db_name));
 		if (tdb_lockall(ctdb_db->ltdb->tdb) != 0) {
 			return -1;
diff --git a/server/ctdb_recover.c b/server/ctdb_recover.c
index 40544f1..21dc28d 100644
--- a/server/ctdb_recover.c
+++ b/server/ctdb_recover.c
@@ -44,10 +44,30 @@ static int ctdb_lock_all_databases_mark(struct ctdb_context *ctdb, uint32_t prio
 		DEBUG(DEBUG_ERR,("Attempt to mark all databases locked when not frozen\n"));
 		return -1;
 	}
+	/* The dual loop is a woraround for older versions of samba
+	   that does not yet support the set-db-priority/lock order
+	   call. So that we get basic deadlock avoiidance also for
+	   these old versions of samba.
+	   This code will be removed in the future.
+	*/
 	for (ctdb_db=ctdb->db_list;ctdb_db;ctdb_db=ctdb_db->next) {
 		if (ctdb_db->priority != priority) {
 			continue;
 		}
+		if (strstr(ctdb_db->db_name, "notify") != NULL) {
+			continue;
+		}
+		if (tdb_lockall_mark(ctdb_db->ltdb->tdb) != 0) {
+			return -1;
+		}
+	}
+	for (ctdb_db=ctdb->db_list;ctdb_db;ctdb_db=ctdb_db->next) {
+		if (ctdb_db->priority != priority) {
+			continue;
+		}
+		if (strstr(ctdb_db->db_name, "notify") == NULL) {
+			continue;
+		}
 		if (tdb_lockall_mark(ctdb_db->ltdb->tdb) != 0) {
 			return -1;
 		}


-- 
CTDB repository