svn commit: samba r14955 - in trunk/source: nsswitch smbd tdb

[jra at samba.org]

Author: jra
Date: 2006-04-06 22:31:47 +0000 (Thu, 06 Apr 2006)
New Revision: 14955

WebSVN: http://websvn.samba.org/cgi-bin/viewcvs.cgi?view=rev&root=samba&rev=14955

Log:
Fix #3569 based on William Jojo's work. AIX also
has the linear posix locking issue which causes
CLEAR_IF_FIRST to cause performance problems.
As we know we're in a daemon architecture with
long-lived parent we can avoid this in the Samba
case. Add a comment explaining this.
Jeremy.

Modified:
   trunk/source/nsswitch/winbindd_dual.c
   trunk/source/smbd/server.c
   trunk/source/tdb/tdb.c
   trunk/source/tdb/tdb.h
   trunk/source/tdb/tdbtorture.c


Changeset:
Modified: trunk/source/nsswitch/winbindd_dual.c
===================================================================
--- trunk/source/nsswitch/winbindd_dual.c	2006-04-06 22:31:45 UTC (rev 14954)
+++ trunk/source/nsswitch/winbindd_dual.c	2006-04-06 22:31:47 UTC (rev 14955)
@@ -629,7 +629,7 @@
 	close(fdpair[1]);
 
 	/* tdb needs special fork handling */
-	if (tdb_reopen_all() == -1) {
+	if (tdb_reopen_all(1) == -1) {
 		DEBUG(0,("tdb_reopen_all failed.\n"));
 		_exit(0);
 	}

Modified: trunk/source/smbd/server.c
===================================================================
--- trunk/source/smbd/server.c	2006-04-06 22:31:45 UTC (rev 14954)
+++ trunk/source/smbd/server.c	2006-04-06 22:31:47 UTC (rev 14955)
@@ -474,7 +474,7 @@
 
 				set_need_random_reseed();
 				/* tdb needs special fork handling - remove CLEAR_IF_FIRST flags */
-				if (tdb_reopen_all() == -1) {
+				if (tdb_reopen_all(1) == -1) {
 					DEBUG(0,("tdb_reopen_all failed.\n"));
 					smb_panic("tdb_reopen_all failed.");
 				}

Modified: trunk/source/tdb/tdb.c
===================================================================
--- trunk/source/tdb/tdb.c	2006-04-06 22:31:45 UTC (rev 14954)
+++ trunk/source/tdb/tdb.c	2006-04-06 22:31:47 UTC (rev 14955)
@@ -2098,11 +2098,27 @@
 }
 
 /* reopen all tdb's */
-int tdb_reopen_all(void)
+int tdb_reopen_all(int parent_longlived)
 {
 	TDB_CONTEXT *tdb;
 
 	for (tdb=tdbs; tdb; tdb = tdb->next) {
+		/*
+		 * If the parent is longlived (ie. a
+		 * parent daemon architecture), we know
+		 * it will keep it's active lock on a
+		 * tdb opened with CLEAR_IF_FIRST. Thus
+		 * for child processes we don't have to
+		 * add an active lock. This is essential
+		 * to improve performance on systems that
+		 * keep POSIX locks as a non-scalable data
+		 * structure in the kernel.
+		 */
+		if (parent_longlived) {
+			/* Ensure no clear-if-first. */
+			tdb->flags &= ~TDB_CLEAR_IF_FIRST;
+		}
+
 		if (tdb_reopen(tdb) != 0)
 			return -1;
 	}

Modified: trunk/source/tdb/tdb.h
===================================================================
--- trunk/source/tdb/tdb.h	2006-04-06 22:31:45 UTC (rev 14954)
+++ trunk/source/tdb/tdb.h	2006-04-06 22:31:47 UTC (rev 14955)
@@ -128,7 +128,7 @@
 			 tdb_hash_func hash_fn);
 
 int tdb_reopen(TDB_CONTEXT *tdb);
-int tdb_reopen_all(void);
+int tdb_reopen_all(int);
 void tdb_logging_function(TDB_CONTEXT *tdb, tdb_log_func);
 enum TDB_ERROR tdb_error(TDB_CONTEXT *tdb);
 const char *tdb_errorstr(TDB_CONTEXT *tdb);

Modified: trunk/source/tdb/tdbtorture.c
===================================================================
--- trunk/source/tdb/tdbtorture.c	2006-04-06 22:31:45 UTC (rev 14954)
+++ trunk/source/tdb/tdbtorture.c	2006-04-06 22:31:47 UTC (rev 14955)
@@ -103,7 +103,7 @@
 
 #if REOPEN_PROB
 	if (random() % REOPEN_PROB == 0) {
-		tdb_reopen_all();
+		tdb_reopen_all(1);
 		goto next;
 	} 
 #endif
@@ -192,7 +192,7 @@
 	for (i=0;i<NPROC;i++) {
 		pids[i] = fork();
 		if (pids[i] == 0) {
-			tdb_reopen_all();
+			tdb_reopen_all(1);
 
 			tdb_logging_function(db, tdb_log);