From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54308) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1an7lr-0007kU-9Q for qemu-devel@nongnu.org; Mon, 04 Apr 2016 12:54:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1an7ln-0005KH-96 for qemu-devel@nongnu.org; Mon, 04 Apr 2016 12:54:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43062) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1an7ln-0005KC-1U for qemu-devel@nongnu.org; Mon, 04 Apr 2016 12:54:31 -0400 References: <1458742562-30624-1-git-send-email-den@openvz.org> <56F4654D.2020700@redhat.com> <20160325084929.GA2671@grep.be> <1580868.I2qeg0bkmp@adelgunde> From: Eric Blake Message-ID: <57029C45.5020202@redhat.com> Date: Mon, 4 Apr 2016 10:54:29 -0600 MIME-Version: 1.0 In-Reply-To: <1580868.I2qeg0bkmp@adelgunde> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="BKu2IGiLk1Ql7v0fVhMWGkpBi3gUVHxI8" Subject: Re: [Qemu-devel] [Nbd] [PATCH 2/2] NBD proto: add GET_LBA_STATUS extension List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Pargmann , Wouter Verhelst Cc: nbd-general@lists.sourceforge.net, Kevin Wolf , qemu-devel@nongnu.org, Stefan Hajnoczi , Paolo Bonzini , "Denis V. Lunev" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --BKu2IGiLk1Ql7v0fVhMWGkpBi3gUVHxI8 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 04/04/2016 04:18 AM, Markus Pargmann wrote: > Hi, >=20 > back from my easter vacation. A bit surprised to find 200 mails in the > NBD mailing list ;). >=20 >> Yes. This has been discussed on the nbd-general list in the past. Ther= e >> is also the (significant) problem of the server having maybe already >> sent out the header before discovering there is an error, at which poi= nt >> it can *only* drop the connection. >=20 > I am still not through all the new mails on the list, so there may be > some more discussions about this. But I will answer here simply. >=20 > I generally like the idea of having this new kind of reply. Is this > solving our issues where we want to "stream" data directly from a > filedescriptor into a tcp-stream? I'm a relative newcomer on the NBD list, so I'm not sure what the issue was there, but yes, structured replies DOES help with read semantics that encounter a partial error that can be detected only after you have started the reply stream. >=20 > Does it make sense to extend this for reads with an offset? This way we= > could not only send in chunks but also order them randomly. Is there an= y > use-case where it does make sense to read data not sequentially? In fact, that's what already got committed while you were gone. It may help if you jump in and read the current state of proto.md, if you don't want to plow through all the mail churn in the meantime for how we got to the state committed. And of course, if you have suggestions on how to further improve it, the extension is still documented as experimental, so we can further tweak it before releasing upstream NBD or downstream QEMU implementations of the extension (I'm currently coding up the work on a qemu implementation, and will report on anything that I run into during that process). --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --BKu2IGiLk1Ql7v0fVhMWGkpBi3gUVHxI8 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJXApxFAAoJEKeha0olJ0NqcNgIAIBuZKws+JD6kSUb2mmUmFei hL282cJASBJPoCorVkQbZ+BdvfO+N+fg5jJOf0i6x5pcB92SE3va0prLmOSF2vff eXOV/2opcPKrSZK2zc8ei6MO2oYzZw9mKiKJsP6bNOoXpygH//oimB/I5I47bGtS VIsf5VK7wWyd2+WnzxarQov2RvTLlfHc3Ze/43JDITK+DaM+YsnF7HOkT5ZdE3SP L6Mwb6Y/uUFp9ihFLZ1IEWETQL01WH9g4tq8tJ7lm9vpOCf5r9QSPx7ZTMhiK90f fW58k8SlW/LZ5ZGAZGKqvpM13wRQwV+ubnaKpyzGlypR1YnbgTFYDtxwWWRv/x0= =YN/P -----END PGP SIGNATURE----- --BKu2IGiLk1Ql7v0fVhMWGkpBi3gUVHxI8--