Re: [PATCH 0/2] block-backend: Retain permissions after migration

[Kevin Wolf]

Am 25.11.2021 um 14:53 hat Hanna Reitz geschrieben:
> Hi,
> 
> Peng Liang has reported an issue regarding migration of raw images here:
> https://lists.nongnu.org/archive/html/qemu-block/2021-11/msg00673.html
> 
> It turns out that after migrating, all permissions are shared when they
> weren’t before.  The cause of the problem is that we deliberately delay
> restricting the shared permissions until migration is really done (until
> the runstate is no longer INMIGRATE) and first share all permissions;
> but this causes us to lose the original shared permission mask and
> overwrites it with BLK_PERM_ALL, so once we do try to restrict the
> shared permissions, we only again share them all.
> 
> Fix this by saving the set of shared permissions through the first
> blk_perm_set() call that shares all; and add a regression test.
> 
> 
> I don’t believe we have to fix this in 6.2, because I think this bug has
> existed for four years now.  (I.e. it isn’t critical, and it’s no
> regression.)

Feels a bit like a hack, but I guess as long as it works... :-)

Reviewed-by: Kevin Wolf <kwolf@redhat.com>