From: Max Reitz <mre...@redhat.com>
Since df2a6f29a5, bdrv_co_do_writev increases the total_sectors value of
a growable block devices on writes after the current end. This leads to
the virtual disk apparently growing in qcow2_save_vmstate, which in turn
affects the disk size captured by the internal snapshot taken directly
afterwards through e.g. the HMP savevm command. Such a "grown" snapshot
cannot be loaded after reopening the qcow2 image, since its disk size
differs from the actual virtual disk size (writing a VM state does not
actually increase the virtual disk size).
Fix this by restoring total_sectors at the end of qcow2_save_vmstate.
Signed-off-by: Max Reitz <mre...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
block/qcow2.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/block/qcow2.c b/block/qcow2.c
index c1abaff..4a3e8b4 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1939,6 +1939,7 @@ static int qcow2_save_vmstate(BlockDriverState *bs,
QEMUIOVector *qiov,
int64_t pos)
{
BDRVQcowState *s = bs->opaque;
+ int64_t total_sectors = bs->total_sectors;
int growable = bs->growable;
int ret;
@@ -1947,6 +1948,11 @@ static int qcow2_save_vmstate(BlockDriverState *bs,
QEMUIOVector *qiov,
ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov);
bs->growable = growable;
+ /* bdrv_co_do_writev will have increased the total_sectors value to include
+ * the VM state - the VM state is however not an actual part of the block
+ * device, therefore, we need to restore the old value. */
+ bs->total_sectors = total_sectors;
+
return ret;
}
--
1.8.1.4
