[Qemu-devel] Re: [PATCH 1/3] block: allow migration to work with image files

[Juan Quintela]

Kevin Wolf <address@hidden> wrote:
> Am 11.09.2010 16:04, schrieb Anthony Liguori:

> There is a simple generic implementation:
>
> drv = bs->drv;
> drv->close(bs);
> drv->open(bs, bs->open_flags);
>
> Note that this only reopens e.g. the qcow2 layer, but not the image
> file, which is bs->file.
>
> This works for all simple case, that is, one format on top of one or
> more protocols, where the protocols don't need invalidation. I think
> this includes everything that is possible today. With -blockdev we might
> need to revise this to include the lower layers, too. (But only
> sometimes, because we don't want to reopen the file)

we require it for nfs consistency.  We need to:

source: fsync()
target: open() (after the fsync).

About your 1st comment, I am doing:

bdrv_close(bdrv);
bdrv_open(bdrv);

Do you mean that this don't close and open again the file with qcow2?

Later, Juan.