Re: [PATCH for 9.0] migration: Skip only empty block devices

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Tue, Mar 12, 2024 at 01:04:31PM +0100, Cédric Le Goater wrote:
> The block .save_setup() handler calls a helper routine
> init_blk_migration() which builds a list of block devices to take into
> account for migration. When one device is found to be empty (sectors
> == 0), the loop exits and all the remaining devices are ignored. This
> is a regression introduced when bdrv_iterate() was removed.
> 
> Change that by skipping only empty devices.
> 
> Cc: Markus Armbruster <armbru@redhat.com>
> Suggested: Kevin Wolf <kwolf@redhat.com>
> Fixes: fea68bb6e9fa ("block: Eliminate bdrv_iterate(), use bdrv_next()")

It's not clear to me that fea68bb6e9fa introduced the bug. The code is
still <= 0 there and I don't see anything else that skips empty devices.
Can you explain the bug in fea68bb6e9fa?

Otherwise:
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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