--- a/usr/src/uts/common/fs/zfs/zio.c Mon Jan 23 18:43:32 2012 -0800
+++ b/usr/src/uts/common/fs/zfs/zio.c Mon Jan 23 18:47:28 2012 -0800
@@ -20,7 +20,7 @@
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright (c) 2012 by Delphix. All rights reserved.
* Copyright (c) 2011 Nexenta Systems, Inc. All rights reserved.
*/
@@ -2219,13 +2219,22 @@
ASSERT(txg > spa_syncing_txg(spa));
- if (use_slog)
+ /*
+ * ZIL blocks are always contiguous (i.e. not gang blocks) so we
+ * set the METASLAB_GANG_AVOID flag so that they don't "fast gang"
+ * when allocating them.
+ */
+ if (use_slog) {
error = metaslab_alloc(spa, spa_log_class(spa), size,
- new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID);
-
- if (error)
+ new_bp, 1, txg, old_bp,
+ METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID);
+ }
+
+ if (error) {
error = metaslab_alloc(spa, spa_normal_class(spa), size,
- new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID);
+ new_bp, 1, txg, old_bp,
+ METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID);
+ }
if (error == 0) {
BP_SET_LSIZE(new_bp, size);