Update to onnv_147

[zfs.git] / module / zfs / refcount.c

diff --git a/module/zfs/refcount.c b/module/zfs/refcount.c
index 8358b4c..600132f 100644 (file)
--- a/module/zfs/refcount.c
+++ b/module/zfs/refcount.c
@@ -25,7 +25,7 @@
 #include <sys/zfs_context.h>
 #include <sys/refcount.h>
 
-#if defined(DEBUG) || !defined(_KERNEL)
+#ifdef ZFS_DEBUG
 
 #ifdef _KERNEL
 int reference_tracking_enable = FALSE; /* runs out of memory too easily */
@@ -189,4 +189,35 @@ refcount_remove(refcount_t *rc, void *holder)
        return (refcount_remove_many(rc, 1, holder));
 }
 
-#endif
+void
+refcount_transfer(refcount_t *dst, refcount_t *src)
+{
+       int64_t count, removed_count;
+       list_t list, removed;
+
+       list_create(&list, sizeof (reference_t),
+           offsetof(reference_t, ref_link));
+       list_create(&removed, sizeof (reference_t),
+           offsetof(reference_t, ref_link));
+
+       mutex_enter(&src->rc_mtx);
+       count = src->rc_count;
+       removed_count = src->rc_removed_count;
+       src->rc_count = 0;
+       src->rc_removed_count = 0;
+       list_move_tail(&list, &src->rc_list);
+       list_move_tail(&removed, &src->rc_removed);
+       mutex_exit(&src->rc_mtx);
+
+       mutex_enter(&dst->rc_mtx);
+       dst->rc_count += count;
+       dst->rc_removed_count += removed_count;
+       list_move_tail(&dst->rc_list, &list);
+       list_move_tail(&dst->rc_removed, &removed);
+       mutex_exit(&dst->rc_mtx);
+
+       list_destroy(&list);
+       list_destroy(&removed);
+}
+
+#endif /* ZFS_DEBUG */