tree cecddf3bbb42ae79bc6262293446d7ad73ba1601
parent a561ddbec156c73ecf2852d77574ddef52970dcf
author Mike Snitzer <snitzer@redhat.com> 1377025361 -0400
committer Mike Snitzer <snitzer@redhat.com> 1377262934 -0400

dm thin: fix stacking of geometry limits

Do not blindly override the queue limits (specifically io_min and
io_opt).  Allow traditional stacking of these limits if io_opt is a
factor of the thin-pool's data block size.

Without this patch mkfs.xfs does not recognize the thin device's
provided limits as a useful geometry (e.g. raid) so these hints are
ignored.  This was due to setting io_min to a useless value.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>