svn commit: r306423 - vendor-sys/illumos/dist/uts/common/fs/zfs

[Alexander Motin]

Author: mav
Date: Wed Sep 28 23:46:08 2016
New Revision: 306423
URL: https://svnweb.freebsd.org/changeset/base/306423

Log:
  7402 Create tunable to ignore hole_birth feature
  
  Until we can resolve the numerous hole_birth bugs that have cropped up
  recently, and come up with a way going forwards to protect users from
  corruption, we should disable the hole_birth feature.  Using a tunable
  allows those who are confident that their data is correct to continue to
  take advantage of the feature.
  
  Closes #188
  
  Reviewed by: Matthew Ahrens <mahrens at delphix.com>
  Author: Paul Dagnelie <pcd at delphix.com>

Modified:
  vendor-sys/illumos/dist/uts/common/fs/zfs/dmu_traverse.c

Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/dmu_traverse.c
==============================================================================
--- vendor-sys/illumos/dist/uts/common/fs/zfs/dmu_traverse.c	Wed Sep 28 23:44:13 2016	(r306422)
+++ vendor-sys/illumos/dist/uts/common/fs/zfs/dmu_traverse.c	Wed Sep 28 23:46:08 2016	(r306423)
@@ -39,6 +39,7 @@
 #include <sys/zfeature.h>
 
 int32_t zfs_pd_bytes_max = 50 * 1024 * 1024;	/* 50MB */
+boolean_t send_holes_without_birth_time = B_TRUE;
 
 typedef struct prefetch_data {
 	kmutex_t pd_mtx;
@@ -253,7 +254,8 @@ traverse_visitbp(traverse_data_t *td, co
 		 *
 		 * Note that the meta-dnode cannot be reallocated.
 		 */
-		if ((!td->td_realloc_possible ||
+		if (!send_holes_without_birth_time &&
+		    (!td->td_realloc_possible ||
 		    zb->zb_object == DMU_META_DNODE_OBJECT) &&
 		    td->td_hole_birth_enabled_txg <= td->td_min_txg)
 			return (0);