From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36827) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TOCn3-0001de-5p for qemu-devel@nongnu.org; Tue, 16 Oct 2012 15:27:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TOCmx-0006k3-9o for qemu-devel@nongnu.org; Tue, 16 Oct 2012 15:26:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50637) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TOCmx-0006jm-1r for qemu-devel@nongnu.org; Tue, 16 Oct 2012 15:26:51 -0400 Message-ID: <507DB4F2.3090309@redhat.com> Date: Tue, 16 Oct 2012 13:26:42 -0600 From: Eric Blake MIME-Version: 1.0 References: <1350409868-2117-1-git-send-email-coreyb@linux.vnet.ibm.com> In-Reply-To: <1350409868-2117-1-git-send-email-coreyb@linux.vnet.ibm.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig45DCEE5DA7190E6D72A586B3" Subject: Re: [Qemu-devel] [PATCH v3 0/4] command line fd passing using fd sets List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Corey Bryant Cc: kwolf@redhat.com, libvir-list@redhat.com, qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig45DCEE5DA7190E6D72A586B3 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 10/16/2012 11:51 AM, Corey Bryant wrote: > This series adds command line file descriptor passing support > via a new -add-fd option. This is a follow-on to the existing > QMP fd passing support provided in the following patch series: > comments.gmane.org/gmane.comp.emulators.qemu/165463 >=20 > The new -add-fd option is designed to mirror the add-fd QMP > option as much as possible. Before this can still be useful in libvirt, we need a way to pass in fds for all of a backing chain, and not just the top-level. And you can't argue that libvirt should be temporarily rewriting qcow2 metadata to stick in names such as /dev/fdset/1 into the metadata. Consider the case of: /- guest1.img base.img <- snap1.img < \- guest2.img snap1.img is supposed to be read-only, and there's no guarantee that /dev/fdset/1 will be available for both guest1 and guest2 to rewrite the header. Thus, I argue that snap1.img must encode the name base.img in its metadata, but that we must also have a way to tell qemu to open /dev/fdset/1 instead of trying open(base.img) in order to get the open fd for base.img. But even though we are still not at a point where the overall feature is useful, I can at least review these patches for getting us incrementally closer to our goal. --=20 Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enig45DCEE5DA7190E6D72A586B3 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQEcBAEBCAAGBQJQfbTyAAoJEKeha0olJ0NqMIoH/i6CgCBSl6ExRZJPxkAs2Z1e u9GATxqE0UlK/Vtja0sf2RXZKYJbw+iyknDiUyTtBhc4AOZyuf2oakCh3/ZVYN+6 VulQ2Mv3aSbAUZgVc5ZvIjlXdI/4Wx0J4G7MVfwHT8+/iFRPIvfLERx57tywksst mEP76KC2YjSUAbnMRpX1XhKu/bSpItFr5tK3ICog0CuyDmbEdxmU8xsh0K9ebrKv vNhEb2F9oaqAXYV+rJnrX38PyVKI6mij2AqcvUe0xIAM+A1zxi0fe824JYNzSXjG wryqvmWA2uAoV6XTDqM+zCfR4D3RwsII9iKIdFdxYVx0hJ8dsKfb5BsF8sMq/Jg= =Zi8E -----END PGP SIGNATURE----- --------------enig45DCEE5DA7190E6D72A586B3--