Commit eedff66f authored Oct 20, 2013 by Max Reitz Committed by Kevin Wolf Oct 24, 2013

qcow2: Restore total_sectors value in save_vmstate

Since df2a6f29, 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 <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

parent cc94712b

block/qcow2.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}