r15100: Port the bugfix for #3569 to Samba4

(This used to be commit 5f1d52f232051324082b840f29dd7719a9328bd5)

3 files changed, 19 insertions, 3 deletions

diff --git a/source4/lib/tdb/common/open.c b/source4/lib/tdb/common/open.c
index 7ebc067175..cb4a9cd994 100644
--- a/source4/lib/tdb/common/open.c
+++ b/source4/lib/tdb/common/open.c
@@ -424,11 +424,27 @@ fail:
 }
 
 /* reopen all tdb's */
-int tdb_reopen_all(void)
+int tdb_reopen_all(int parent_longlived)
 {
 	struct 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/source4/lib/tdb/include/tdb.h b/source4/lib/tdb/include/tdb.h
index ddde17850b..4004c73460 100644
--- a/source4/lib/tdb/include/tdb.h
+++ b/source4/lib/tdb/include/tdb.h
@@ -87,7 +87,7 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 			 tdb_hash_func hash_fn);
 
 int tdb_reopen(struct tdb_context *tdb);
-int tdb_reopen_all(void);
+int tdb_reopen_all(int parent_longlived);
 void tdb_logging_function(struct tdb_context *tdb, tdb_log_func);
 enum TDB_ERROR tdb_error(struct tdb_context *tdb);
 const char *tdb_errorstr(struct tdb_context *tdb);
diff --git a/source4/lib/tdb/tools/tdbtorture.c b/source4/lib/tdb/tools/tdbtorture.c
index 840397b73b..ac09898696 100644
--- a/source4/lib/tdb/tools/tdbtorture.c
+++ b/source4/lib/tdb/tools/tdbtorture.c
@@ -149,7 +149,7 @@ static void addrec_db(void)
 
 #if REOPEN_PROB
 	if (in_transaction == 0 && random() % REOPEN_PROB == 0) {
-		tdb_reopen_all();
+		tdb_reopen_all(0);
 		goto next;
 	} 
 #endif