From aa1df6fcd4c2dbfd39cac3e1d68208cca61643ce Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Sat, 13 Jun 2015 16:22:23 +0200
Subject: [PATCH 29/42] qcow2: Clean up after refcount rebuild

Message-id: <1434212556-3927-30-git-send-email-mreitz@redhat.com>
Patchwork-id: 66048
O-Subject: [RHEL-7.2 qemu-kvm PATCH 29/42] qcow2: Clean up after refcount rebuild
Bugzilla: 1129893
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

BZ: 1129893

Because the old refcount structure will be leaked after having rebuilt
it, we need to recalculate the refcounts and run a leak-fixing operation
afterwards (if leaks should be fixed at all).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 791230d8bbd5c09d80845755a54074cd2d8b5a22)

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block/qcow2-refcount.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 651ddb6..fe36bbd 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1983,12 +1983,57 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
                       nb_clusters);
 
     if (rebuild && (fix & BDRV_FIX_ERRORS)) {
+        BdrvCheckResult old_res = *res;
+        int fresh_leaks = 0;
+
         fprintf(stderr, "Rebuilding refcount structure\n");
         ret = rebuild_refcount_structure(bs, res, &refcount_table,
                                          &nb_clusters);
         if (ret < 0) {
             goto fail;
         }
+
+        res->corruptions = 0;
+        res->leaks = 0;
+
+        /* Because the old reftable has been exchanged for a new one the
+         * references have to be recalculated */
+        rebuild = false;
+        memset(refcount_table, 0, nb_clusters * sizeof(uint16_t));
+        ret = calculate_refcounts(bs, res, 0, &rebuild, &refcount_table,
+                                  &nb_clusters);
+        if (ret < 0) {
+            goto fail;
+        }
+
+        if (fix & BDRV_FIX_LEAKS) {
+            /* The old refcount structures are now leaked, fix it; the result
+             * can be ignored, aside from leaks which were introduced by
+             * rebuild_refcount_structure() that could not be fixed */
+            BdrvCheckResult saved_res = *res;
+            *res = (BdrvCheckResult){ 0 };
+
+            compare_refcounts(bs, res, BDRV_FIX_LEAKS, &rebuild,
+                              &highest_cluster, refcount_table, nb_clusters);
+            if (rebuild) {
+                fprintf(stderr, "ERROR rebuilt refcount structure is still "
+                        "broken\n");
+            }
+
+            /* Any leaks accounted for here were introduced by
+             * rebuild_refcount_structure() because that function has created a
+             * new refcount structure from scratch */
+            fresh_leaks = res->leaks;
+            *res = saved_res;
+        }
+
+        if (res->corruptions < old_res.corruptions) {
+            res->corruptions_fixed += old_res.corruptions - res->corruptions;
+        }
+        if (res->leaks < old_res.leaks) {
+            res->leaks_fixed += old_res.leaks - res->leaks;
+        }
+        res->leaks += fresh_leaks;
     } else if (fix) {
         if (rebuild) {
             fprintf(stderr, "ERROR need to rebuild refcount structures\n");
-- 
1.8.3.1