[dm-devel] [PATCH 1/1] dm raid: fix compat_features validation

[Mike Snitzer]

On Tue, Oct 11 2016 at 10:28am -0400,
Andy Whitcroft <apw at canonical.com> wrote:

> In commit ecbfb9f118bce4 ("dm raid: add raid level takeover support") a new
> compatible feature flag was added.  Validation for these compat_features
> was added but this only passes for new raid mappings with this feature
> flag.  This causes previously created raid mappings to be failed at import.
> 
> Check compat_features for any valid combinations.
> 
> Fixes: ecbfb9f118bce4 ("dm raid: add raid level takeover support")
> BugLink: http://bugs.launchpad.net/bugs/1631298
> Signed-off-by: Andy Whitcroft <apw at canonical.com>
> ---
>  drivers/md/dm-raid.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> It very much looks like these are intended to be optional extended feature
> flags.  That we should be accepting any valid flag and rejecting any bit
> not in that set.  We should however not be ensuring that specific bits
> are actually set.  Certainly as things stand raid sets built on previous
> kernel versions cannot be assembled.

Right, your patch looks good to me.  But I'll wait for confirmation from
Heinz before I stage your fix.

Thanks,
Mike