svn commit: r286543 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Alexander Motin]

Author: mav
Date: Sun Aug  9 19:29:10 2015
New Revision: 286543
URL: https://svnweb.freebsd.org/changeset/base/286543

Log:
  MFV 286542: 5592 NULL pointer dereference in dsl_prop_notify_all_cb()
  
  Reviewed by: Dan McDonald <danmcd at omniti.com>
  Reviewed by: Matthew Ahrens <mahrens at delphix.com>
  Reviewed by: George Wilson <george at delphix.com>
  Reviewed by: Will Andrews <will at freebsd.org>
  Approved by: Robert Mustacchi <rm at joyent.com>
  
  illumos/illumos-gate at 9d47dec0481d8cd53b2c1053c96bfa3f78357d6a

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c	Sun Aug  9 19:28:31 2015	(r286542)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c	Sun Aug  9 19:29:10 2015	(r286543)
@@ -372,8 +372,19 @@ dsl_dataset_snap_remove(dsl_dataset_t *d
 boolean_t
 dsl_dataset_try_add_ref(dsl_pool_t *dp, dsl_dataset_t *ds, void *tag)
 {
-	return (dmu_buf_try_add_ref(ds->ds_dbuf, dp->dp_meta_objset,
-	    ds->ds_object, DMU_BONUS_BLKID, tag));
+	dmu_buf_t *dbuf = ds->ds_dbuf;
+	boolean_t result = B_FALSE;
+
+	if (dbuf != NULL && dmu_buf_try_add_ref(dbuf, dp->dp_meta_objset,
+	    ds->ds_object, DMU_BONUS_BLKID, tag)) {
+
+		if (ds == dmu_buf_get_user(dbuf))
+			result = B_TRUE;
+		else
+			dmu_buf_rele(dbuf, tag);
+	}
+
+	return (result);
 }
 
 int