On Sun, 23 Nov 2025, Askar Safin wrote:
> Mikulas Patocka <[email protected]>:
> > [PATCH 1/2] pm-hibernate: flush disk cache when suspending
> >
> > There was reported failure that suspend doesn't work with dm-integrity.
> > The reason for the failure is that the suspend code doesn't issue the
> > FLUSH bio - the data still sits in the dm-integrity cache and they are
> > lost when poweroff happens.
>
> I tested this patchset (in Qemu). It works.
>
> Here is script I used for testing:
>
> https://zerobin.net/?66669be7d2404586#xWufhCq7zCoOk3LJcJCj7W4k3vYT3U4vhGutTN3p8m0=
>
> Here are logs:
>
> https://zerobin.net/?5d4a2abbad751890#WMcQl4FAZC9KqcAuJU3TSVr7wuVnPFwI7dlinA9QHOo=
>
> Tested-By: Askar Safin <[email protected]>
>
> There was no any reason to wait for me. You could easily test using script
> above.
>
> Also: Linux shows this scary message when booting in Qemu:
>
> [ 0.512581] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled,
> doesn't support DPO or FUA
>
> So, FUA is not supported? Does it mean that this patch is wrong, and works
> purely
> by chance?
If FUA is not supported by a disk, the kernel would send a flush request
after the write request with the FUA flag. There's no problem with that -
the cache will be flushed correctly.
Mikulas
> --
> Askar Safin
>
