[dm-devel] dm-crypt: Reject sector_size feature if device length is not aligned to it

[Mike Snitzer]

On Tue, Oct 03 2017 at  8:05am -0400,
Alasdair G Kergon <agk at redhat.com> wrote:

> On Mon, Oct 02, 2017 at 10:43:56AM -0400, Mikulas Patocka wrote:
> > Here I send a patch that checks invalid limits when the table is loaded 
> > and aborts the table load ioctl with an error.
>  
> The code does not already do this because it needs to avoid unnecessary
> failures if any characteristics of the devices underneath change after
> the 'load' but before the 'resume' (as can happen, for example, when a
> tree of devices gets updated by performing all the loads before all the
> resumes).

Not sure why you're putting such value on that behaviour.  The earlier
we catch invalid tables the better off we are.  Failing at resume time
sucks (always has).

Could be there is some specific scenario where lvm2 is leveraging this
historic DM "feature" but it'd be nice to revalidate the need.

Mike