On 02/22/2017 10:51 AM, Paolo Bonzini wrote: > > > On 21/02/2017 03:42, Eric Blake wrote: >> + /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size >> + * according to whether the client requested it, and according to >> + * whether this is OPT_INFO or OPT_GO. */ >> + /* minimum - 1 for back-compat, or 512 if client is new enough. >> + * TODO: consult blk_bs(blk)->request_align? */ >> + sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1; >> + /* preferred - At least 4096, but larger as appropriate. */ >> + sizes[1] = MAX(blk_get_opt_transfer(exp->blk), 4096); > > Can we just say zero if the preferred transfer size is unknown?
The NBD specification requires a non-zero power-of-2 number if the server transmits the block size at all; 1 is the ideal number, followed by whatever actual size we learn from the request_align of the device. I added blk_get_opt_transfer() in 3/8; maybe I should just respin the series to also add blk_get_request_align() as well and get rid of the TODO here. In other words, my TODO is probably the result of me not remembering to complete my rebase (since v3 of the series was posted so many months ago). > > Apart from this, it looks good. Thanks; I'll get a respin out soon, with R-b added where they make sense, and with the TODO removed. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
signature.asc
Description: OpenPGP digital signature
