Fix scn_queue races on very old pools

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

diff --git a/module/zfs/dsl_scan.c b/module/zfs/dsl_scan.c
index 55e89b89f06ae38d5cf2b5be72200c74fdaa62ae..085cfd3c56918a3147bf341b51e8ab1f8bc9ee28 100644 (file)
--- a/module/zfs/dsl_scan.c
+++ b/module/zfs/dsl_scan.c
@@ -491,6 +491,7 @@ dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
 
        avl_create(&scn->scn_queue, scan_ds_queue_compare, sizeof (scan_ds_t),
            offsetof(scan_ds_t, sds_node));
+       mutex_init(&scn->scn_queue_lock, NULL, MUTEX_DEFAULT, NULL);
        avl_create(&scn->scn_prefetch_queue, scan_prefetch_queue_compare,
            sizeof (scan_prefetch_issue_ctx_t),
            offsetof(scan_prefetch_issue_ctx_t, spic_avl_node));
@@ -646,6 +647,7 @@ dsl_scan_fini(dsl_pool_t *dp)
 
                scan_ds_queue_clear(scn);
                avl_destroy(&scn->scn_queue);
+               mutex_destroy(&scn->scn_queue_lock);
                scan_ds_prefetch_queue_clear(scn);
                avl_destroy(&scn->scn_prefetch_queue);
 
@@ -2723,8 +2725,10 @@ enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
                        return (err);
                ds = prev;
        }
+       mutex_enter(&scn->scn_queue_lock);
        scan_ds_queue_insert(scn, ds->ds_object,
            dsl_dataset_phys(ds)->ds_prev_snap_txg);
+       mutex_exit(&scn->scn_queue_lock);
        dsl_dataset_rele(ds, FTAG);
        return (0);
 }
@@ -2915,8 +2919,10 @@ enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
                ds = prev;
        }
 
+       mutex_enter(&scn->scn_queue_lock);
        scan_ds_queue_insert(scn, ds->ds_object,
            dsl_dataset_phys(ds)->ds_prev_snap_txg);
+       mutex_exit(&scn->scn_queue_lock);
        dsl_dataset_rele(ds, FTAG);
        return (0);
 }