From: Andrew Tridgell <tridge@samba.org>
Date: Tue, 16 Dec 2008 03:36:56 +0000 (+1100)
Subject: make tdbbackup use transactions
X-Git-Tag: samba-4.0.0alpha6~478
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2e4247782bd5812bc8e7ea24194c8436748bb2fa;p=thirdparty%2Fsamba.git

make tdbbackup use transactions

tdbbackup was originally written before we had transactions, and it
attempted to use its own fsync() calls to make it safe. Now that we
have transactions we can do it in a much safer (and faster!) fashion
---

diff --git a/lib/tdb/tools/tdbbackup.c b/lib/tdb/tools/tdbbackup.c
index 6f3ca48314f..83c0e16399e 100644
--- a/lib/tdb/tools/tdbbackup.c
+++ b/lib/tdb/tools/tdbbackup.c
@@ -126,9 +126,17 @@ static int backup_tdb(const char *old_name, const char *new_name, int hash_size)
 		return 1;
 	}
 
-	/* lock the old tdb */
-	if (tdb_lockall(tdb) != 0) {
-		fprintf(stderr,"Failed to lock %s\n", old_name);
+	if (tdb_transaction_start(tdb) != 0) {
+		printf("Failed to start transaction on old tdb\n");
+		tdb_close(tdb);
+		tdb_close(tdb_new);
+		unlink(tmp_name);
+		free(tmp_name);
+		return 1;
+	}
+
+	if (tdb_transaction_start(tdb_new) != 0) {
+		printf("Failed to start transaction on new tdb\n");
 		tdb_close(tdb);
 		tdb_close(tdb_new);
 		unlink(tmp_name);
@@ -152,6 +160,14 @@ static int backup_tdb(const char *old_name, const char *new_name, int hash_size)
 	/* close the old tdb */
 	tdb_close(tdb);
 
+	if (tdb_transaction_commit(tdb_new) != 0) {
+		fprintf(stderr, "Failed to commit new tdb\n");
+		tdb_close(tdb_new);
+		unlink(tmp_name);
+		free(tmp_name);		
+		return 1;
+	}
+
 	/* close the new tdb and re-open read-only */
 	tdb_close(tdb_new);
 	tdb_new = tdb_open(tmp_name, 0, TDB_DEFAULT, O_RDONLY, 0);
@@ -173,9 +189,6 @@ static int backup_tdb(const char *old_name, const char *new_name, int hash_size)
 		return 1;
 	}
 
-	/* make sure the new tdb has reached stable storage */
-	fsync(tdb_fd(tdb_new));
-
 	/* close the new tdb and rename it to .bak */
 	tdb_close(tdb_new);
 	if (rename(tmp_name, new_name) != 0) {