[linux-lvm] cache_check --clear-needs-check-flag does not clear needs_check flag?

[David Teigland]

On Wed, Dec 09, 2020 at 08:57:07PM +0100, Dennis Schridde wrote:
> On Mittwoch, 9. Dezember 2020 20:30:51 CET David Teigland wrote:
> > On Wed, Dec 09, 2020 at 08:06:41PM +0100, Dennis Schridde wrote:
> > > How would you proceed to repair this cache?  I can recreate it as a
> > > cachepool, but first I need to gain back access to the data, i.e. get
> > > into a state where I can --uncache.
> >
> > I know that cachevols do not yet work with lvconvert --repair, which uses
> > cache_repair, but this must be another case where cache_repair is still
> > needed.  If this is writethough mode you should be able to simply drop the
> > cache with lvconvert --splitcache and then recreate it.
> 
> Sadly the cache is in writeback mode.
> 
> Is my understanding correct that the cache itself is fine?  It is just the
> inability to clear the needs_check flag that is preventing me from using the
> device?  

I suspect the cache itself is fine and we're just missing a way to clear
that flag in the cache metadata.  I'm looking for a workaround for that
until we can sort out a complete fix.

Dave