20.06.2018 20:17, Vladimir Sementsov-Ogievskiy wrote:
13.06.2018 01:18, John Snow wrote:
On 06/12/2018 06:11 PM, John Snow wrote:
On 06/12/2018 01:26 PM, Vladimir Sementsov-Ogievskiy wrote:
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 <vsement...@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;
Ah, tch... I didn't realize that invalidate completely wipes the qcow2
metadata.
I guess the other three fields, nb_bitmaps, bitmap_directory_size and
bitmap_directory_offset get initialized again on re-open.
(I suppose this means I need to rethink caching bm_list more carefully,
too...)
I think this looks correct mechanically.
Oh, I meant:
Reviewed-by: John Snow <js...@redhat.com>
It is interesting, this patch also fixes iotest 169. It's not broken
formally, but if we look at vm output of vm_b after migration, we'll see
qemu-system-x86_64: Could not reopen qcow2 layer: Bitmap already
exists: bitmap0
which leads to failed invalidation and bs->drv = NULL :)
I'll improve iotest somehow, to show this failure.
the bug can be shown with the following workaround:
diff --git a/tests/qemu-iotests/169 b/tests/qemu-iotests/169
index f243db9955..6dce24d29f 100755
--- a/tests/qemu-iotests/169
+++ b/tests/qemu-iotests/169
@@ -131,9 +131,13 @@ class TestDirtyBitmapMigration(iotests.QMPTestCase):
break
self.check_bitmap(self.vm_b, sha256 if should_migrate else False)
+ self.vm_b.hmp_qemu_io('drive0', 'write 0 512')
if should_migrate:
self.vm_b.shutdown()
+ print '===='
+ print self.vm_b.get_log()
+ print '===='
# recreate vm_b, as we don't want -incoming option (this
will lead
# to "cat" process left alive after test finish)
self.vm_b = iotests.VM(path_suffix='b')
@@ -152,7 +156,8 @@ for cmb in list(itertools.product((True, False),
repeat=4)):
name += '_online' if cmb[2] else '_offline'
name += '_shared' if cmb[3] else '_nonshared'
- inject_test_case(TestDirtyBitmapMigration, name, 'do_test_migration',
+ if name == '_persistent__not_migbitmap__offline_shared':
+ inject_test_case(TestDirtyBitmapMigration, name,
'do_test_migration',
*list(cmb))
--
Best regards,
Vladimir
