On Mon, Nov 11, 2013 at 5:15 PM, Alasdair G Kergon <agk@xxxxxxxxxx> wrote: > Could you make the case that this interface is only intended for use > when using the cache in a mode that doesn't have dirty blocks? This really isn't even an "interface". All this patch enables a user to do is shrink the cache device is they have taken care to not have dirty blocks (be it "cleaner" policy or passthrough or writethrough operation modes). > And that the mechanism for shrinking a cache with dirty blocks has not > yet been developed but might use a quite different interface? We can add an interface to instruct the cache to clean all dirty blocks >= a particular size [1]. Whereby enabling even dirty/hot caches to remain generally useful while allowing to shrink the fast device. But no I'm not prepared to predict what that'll look like, and no that doesn't invalidate the basic support that this patch is providing. We'll improve the docs but there is no reason to withhold this patch waiting for more add-ons. By the time lvm2 has support for dm-cache this very likely won't be a concern anyway (e.g. we'll have the ability to do [1] above). -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
