On 07/04/2016 07:49 AM, Peter Lieven wrote: > Hi, > > the above commit: > > commit d05aa8bb4a8b6aa9a915ec5074fb12ae632d2323 > Author: Eric Blake <ebl...@redhat.com> > Date: Wed Jun 1 15:10:03 2016 -0600 > > block: Add .bdrv_co_pwrite_zeroes() > > introduces a regression (at least for me). > > The Limits from the iSCSI Block Limits VPD have no requirement of being > a power of two. > We use Dell Equallogic iSCSI SANs for instance. They have an internal > page size of 15MB. And > they advertise this page size as max_ws_len, opt_transfer_len and > opt_discard_alignment.
A non-power-of-2 max_ws_len shouldn't be a problem, but opt_transfer_len and opt_discard_alignment not being a power of 2 impacts other code. 15MB is a rather odd page size. > > I think we cannot assert that that these alignments are a power of 2. Perhaps that means we should just fix our code to round things down to the nearest power of 2 (8MB) for the opt_transfer_len and opt_discard_alignment values. Can you post a stack-trace of the actual assertion you are hitting? -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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