Am 06.03.2013 19:06, schrieb Paolo Bonzini:
> Il 06/03/2013 18:50, Peter Lieven ha scritto:
>>>> Commit 9a665b2b made bdrv_truncate() call bdrv_drain_all(), but this breaks
>>>> QCOW images, as well other future image formats (such as VHDX) that may
>>>> call
>>>> bdrv_truncate(bs->file) from within a read/write operation. For example,
>>>> QCOW
>>>> will cause an assert, due to tracked_requests not being empty (since the
>>>> read/write that called bdrv_truncate() is still in progress).
>
> I'm not sure such bdrv_truncate calls are necessary. QCOW2 doesn't have
> them (almost; there is one in qcow2_write_compressed, I'm not even sure
> that one is necessary though), and I think QCOW's breaks using it with a
> block device as a backing file.
I think we have to check the sense of bs->growable nevertheless. It is set
to 1 for all drivers which can't be right?!
int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
{
BlockDriverState *bs;
BlockDriver *drv;
int ret;
drv = bdrv_find_protocol(filename);
if (!drv) {
return -ENOENT;
}
bs = bdrv_new("");
ret = bdrv_open_common(bs, NULL, filename, flags, drv);
if (ret < 0) {
bdrv_delete(bs);
return ret;
}
bs->growable = 1;
*pbs = bs;
return 0;
}
I think each driver should set it accordingly on its own.
Peter
>
> Paolo
>
