On Fri, Aug 19, 2011 at 05:46:04AM -0400, Mike Snitzer wrote: > On Fri, Aug 19 2011 at 5:11am -0400, > Joe Thornber <thornber@xxxxxxxxxx> wrote: > > > On Fri, Aug 19, 2011 at 03:04:36AM -0400, Mike Snitzer wrote: > > > Question for Joe: > > > You're making conflicting changes quick enough that I wonder if you > > > and Mikulas will ever converge (e.g. why do multiple block managers need > > > to have access to the same metadata device!?). > > > > They don't; my issue is with getting an oops if they do through user > > error. I clearly said in the commit message that this was a hack to > > get round issues introduced by agk's move to a kmemcache. Cook > > something cleaner up between yourselves, or wait for me to look at it > > again once I've got through some more pressing issues. > > OK, so this kmemcache problem will go away once you switch over to > bufio. Assuming agk doesn't decide to switch over to a kmemcache. Remember bm used to allocate via kmalloc or pages like bufio. > As for stacking, can't we just read the superblock to check if a device > is already in use (would work metadata anyway)? No idea if that'd be > too costly -- probably not: read superblock and check if > THIN_SUPERBLOCK_MAGIC is set. So you've already thought of a scenario where it's worth having two bm instances (one read only). - Joe -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
