dm cache: fix stacking of geometry limits
authorMike Snitzer <snitzer@redhat.com>
Tue, 20 Aug 2013 19:02:41 +0000 (15:02 -0400)
committerMike Snitzer <snitzer@redhat.com>
Fri, 23 Aug 2013 13:02:14 +0000 (09:02 -0400)
commitf610937214e2ac8c4225df9a124ea0de1f030626
tree879998ed1f96546a6dd555debcd74ad09b88be29
parent0cc67cd9c55c4b1f076abca06c922751088e6d86
dm cache: 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 cache's data block size.

Without this patch mkfs.xfs does not recognize the cache 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>
drivers/md/dm-cache-target.c