[Qemu-devel] [PATCH] block/qcow2: fix logic around dirty_bitmaps_loaded

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

First: this variable was introduced to handle reopens. We need it on
following qcow2_do_open, to don't try loading bitmaps again. So, we are
fixing qcow2_invalidate_cache().

However, if we fix only qcow2_invalidate_cache, iotest 169 fails on
case test__persistent__not_migbitmap__online_shared, because on first
target open, source is not yet closed, and is not yet stored bitmaps,
so, we are load nothing. And on second open, dirty_bitmaps_loaded is
already true, but we have no bitmaps to reopen with
qcow2_reopen_bitmaps_rw_hint(). So, we are fixing qcow2_do_open() too.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qcow2.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 6fa5e1d71a..b4216a5830 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1499,7 +1499,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
         {
             qcow2_reopen_bitmaps_rw_hint(bs, &header_updated, &local_err);
         }
-    } else {
+    } else if (s->nb_bitmaps > 0) {
         header_updated = qcow2_load_dirty_bitmaps(bs, &local_err);
         s->dirty_bitmaps_loaded = true;
     }
@@ -2178,6 +2178,7 @@ static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs,
     QDict *options;
     Error *local_err = NULL;
     int ret;
+    bool dirty_bitmaps_loaded = s->dirty_bitmaps_loaded;
 
     /*
      * Backing files are read-only which makes all of their metadata immutable,
@@ -2190,6 +2191,7 @@ static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs,
     qcow2_close(bs);
 
     memset(s, 0, sizeof(BDRVQcow2State));
+    s->dirty_bitmaps_loaded = dirty_bitmaps_loaded;
     options = qdict_clone_shallow(bs->options);
 
     flags &= ~BDRV_O_INACTIVE;
-- 
2.11.1