Provide a fix for kernel panic if receiving recursive deduplicated streams.

Problem reported to vendor.

Illumos ZFS issues:
  3692 Panic on zfs receive of a recursive deduplicated stream

MFC after:	2 weeks

1 files changed, 5 insertions, 4 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c
index 4c1c6ff..ac8221c 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_send.c
@@ -990,6 +990,7 @@ free_guid_map_onexit(void *arg)
 
 	while ((gmep = avl_destroy_nodes(ca, &cookie)) != NULL) {
 		dsl_dataset_long_rele(gmep->gme_ds, gmep);
+		dsl_dataset_rele(gmep->gme_ds, gmep);
 		kmem_free(gmep, sizeof (guid_map_entry_t));
 	}
 	avl_destroy(ca);
@@ -1691,15 +1692,15 @@ add_ds_to_guidmap(const char *name, avl_tree_t *guid_map, uint64_t snapobj)
 	err = dsl_pool_hold(name, FTAG, &dp);
 	if (err != 0)
 		return (err);
-	err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &snapds);
+	gmep = kmem_alloc(sizeof (guid_map_entry_t), KM_SLEEP);
+	err = dsl_dataset_hold_obj(dp, snapobj, gmep, &snapds);
 	if (err == 0) {
-		gmep = kmem_alloc(sizeof (guid_map_entry_t), KM_SLEEP);
 		gmep->guid = snapds->ds_phys->ds_guid;
 		gmep->gme_ds = snapds;
 		avl_add(guid_map, gmep);
 		dsl_dataset_long_hold(snapds, gmep);
-		dsl_dataset_rele(snapds, FTAG);
-	}
+	} else
+		kmem_free(gmep, sizeof (guid_map_entry_t));
 
 	dsl_pool_rele(dp, FTAG);
 	return (err);