svn commit: r306425 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Alexander Motin]

Author: mav
Date: Thu Sep 29 00:00:37 2016
New Revision: 306425
URL: https://svnweb.freebsd.org/changeset/base/306425

Log:
  MFV r306423: 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:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c
Directory Properties:
  head/sys/cddl/contrib/opensolaris/   (props changed)

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c	Wed Sep 28 23:54:47 2016	(r306424)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c	Thu Sep 29 00:00:37 2016	(r306425)
@@ -40,6 +40,11 @@
 #include <sys/zfeature.h>
 
 int32_t zfs_pd_bytes_max = 50 * 1024 * 1024;	/* 50MB */
+boolean_t send_holes_without_birth_time = B_TRUE;
+
+SYSCTL_DECL(_vfs_zfs);
+SYSCTL_UINT(_vfs_zfs, OID_AUTO, send_holes_without_birth_time, CTLFLAG_RWTUN,
+    &send_holes_without_birth_time, 0, "Send holes without birth time");
 
 typedef struct prefetch_data {
 	kmutex_t pd_mtx;
@@ -254,7 +259,8 @@ 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);