Rebase master to b108

[mirror_zfs.git] / module / zfs / dmu_objset.c

diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c
index 7981e06825c472b2d3b896d0b48dd1be9f6c9b77..c9e00d511516e9fb9f9bf480e389cbe0d9e1f35a 100644 (file)
--- a/module/zfs/dmu_objset.c
+++ b/module/zfs/dmu_objset.c
@@ -1213,6 +1213,39 @@ dmu_objset_find_spa(spa_t *spa, const char *name,
        return (err);
 }
 
+/* ARGSUSED */
+int
+dmu_objset_prefetch(char *name, void *arg)
+{
+       dsl_dataset_t *ds;
+
+       if (dsl_dataset_hold(name, FTAG, &ds))
+               return (0);
+
+       if (!BP_IS_HOLE(&ds->ds_phys->ds_bp)) {
+               mutex_enter(&ds->ds_opening_lock);
+               if (!dsl_dataset_get_user_ptr(ds)) {
+                       uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
+                       zbookmark_t zb;
+
+                       zb.zb_objset = ds->ds_object;
+                       zb.zb_object = 0;
+                       zb.zb_level = -1;
+                       zb.zb_blkid = 0;
+
+                       (void) arc_read_nolock(NULL, dsl_dataset_get_spa(ds),
+                           &ds->ds_phys->ds_bp, NULL, NULL,
+                           ZIO_PRIORITY_ASYNC_READ,
+                           ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
+                           &aflags, &zb);
+               }
+               mutex_exit(&ds->ds_opening_lock);
+       }
+
+       dsl_dataset_rele(ds, FTAG);
+       return (0);
+}
+
 void
 dmu_objset_set_user(objset_t *os, void *user_ptr)
 {