From 4ee43dbd477140bd4bf6c42d156dc0a736994da2 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra@samba.org>
Date: Thu, 6 Apr 2006 22:31:45 +0000
Subject: r14954: 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.
 (This used to be commit 3cd5c3df0d1b98dfa90663973ab13b5d3dbf737e)

---
 source3/tdb/tdb.c        | 18 +++++++++++++++++-
 source3/tdb/tdb.h        |  2 +-
 source3/tdb/tdbtorture.c |  4 ++--
 3 files changed, 20 insertions(+), 4 deletions(-)

(limited to 'source3/tdb')

diff --git a/source3/tdb/tdb.c b/source3/tdb/tdb.c
index 4303976087..ad73a1d9aa 100644
--- a/source3/tdb/tdb.c
+++ b/source3/tdb/tdb.c
@@ -2098,11 +2098,27 @@ fail:
 }
 
 /* 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;
 	}
diff --git a/source3/tdb/tdb.h b/source3/tdb/tdb.h
index d1c976cd56..b5b87ee5a5 100644
--- a/source3/tdb/tdb.h
+++ b/source3/tdb/tdb.h
@@ -128,7 +128,7 @@ TDB_CONTEXT *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 			 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);
diff --git a/source3/tdb/tdbtorture.c b/source3/tdb/tdbtorture.c
index d03cc2a610..2d367b91e1 100644
--- a/source3/tdb/tdbtorture.c
+++ b/source3/tdb/tdbtorture.c
@@ -103,7 +103,7 @@ static void addrec_db(void)
 
 #if REOPEN_PROB
 	if (random() % REOPEN_PROB == 0) {
-		tdb_reopen_all();
+		tdb_reopen_all(1);
 		goto next;
 	} 
 #endif
@@ -192,7 +192,7 @@ int main(int argc, char *argv[])
 	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);
 
-- 
cgit