On Tue, 3 Jul 2018, Milan Broz wrote:
> On 07/03/2018 03:21 PM, Mike Snitzer wrote:
> >>
> >> Should we even have the possibility to stop recalculating?
> >>
> >> If the device was recalculating and we activate it without the
> >> "recalculate" flag, what should it do? If the user reads data that haven't
> >> been recalculated yet, we could:
> >> 1. return an error
> >> 2. ignore the non-recalculated checksum and return data
> >> 3. continue with recalculating even if the flag "recalculate" is not
> >> present
> >>
> >> In my opinion, the option 3 is the best. Option 1 makes the device
> >> unreliable and option 2 makes the device silently lose the integrity
> >> protection.
> >
> > Yes, option 3. But you could even error out on table load; though that
> > may be too unforgiving.. reality is userspace needs to account for
> > staying in recalculating mode until it is complete.
>
> I do not think table load error is the way to go.
>
> Can we activate dmintegrity read-only (for example with read-only backend
> device)
> that is not yet fully recalculated?
There's no read-only activation because the journal must be replayed. Most
journaled filesystems also don't provide read-only activation because they
need to replay the journal.
> This can needed in some recovery scenarios... (But her we can use recovery
> mode).
>
> > But to do that they'd need to monitor (similar to how snapshot-merge
> > polls progress?)
>
> For veritysetup I will just add this to "status" command output.
I added a field to the status that show the recalculate position. If
recalculating was never activated, it is "-".
> Milan
Mikulas
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