From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38286) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1afVhv-0003Wu-IF for qemu-devel@nongnu.org; Mon, 14 Mar 2016 12:51:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1afVhu-0003o5-H4 for qemu-devel@nongnu.org; Mon, 14 Mar 2016 12:51:03 -0400 References: <1457970292-12291-1-git-send-email-kwolf@redhat.com> <1457970292-12291-6-git-send-email-kwolf@redhat.com> From: Eric Blake Message-ID: <56E6EBF0.1050509@redhat.com> Date: Mon, 14 Mar 2016 10:50:56 -0600 MIME-Version: 1.0 In-Reply-To: <1457970292-12291-6-git-send-email-kwolf@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="DmGnNiMIeCFnEGfvqKhHuEV5lj7SHUwsT" Subject: Re: [Qemu-devel] [PATCH 5/5] block: Reject writethrough mode except at the root List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf , qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, jsnow@redhat.com, armbru@redhat.com, mreitz@redhat.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --DmGnNiMIeCFnEGfvqKhHuEV5lj7SHUwsT Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 03/14/2016 09:44 AM, Kevin Wolf wrote: > Writethrough mode is going to become a BlockBackend feature rather than= > a BDS one, so forbid it in places where we won't be able to support it > when the code finally matches the envisioned design. >=20 > We only allowed setting the cache mode of non-root nodes after the 2.5 > release, so we're still free to make this change. >=20 > The target of block jobs is now always opened in a writeback mode > because it doesn't have a BlockBackend attached. This makes more sense > anyway because block jobs know when to flush. If the graph is modified > on job completion, the original cache mode moves to the new root, so > for the guest device writethough always stays enabled if it was > configured this way. >=20 > Signed-off-by: Kevin Wolf > --- > block.c | 7 ++++ > blockdev.c | 19 ++++++++- > tests/qemu-iotests/142 | 50 +++++++++++------------ > tests/qemu-iotests/142.out | 98 +++++++++-----------------------------= -------- > 4 files changed, 68 insertions(+), 106 deletions(-) >=20 Reviewed-by: Eric Blake > +++ b/tests/qemu-iotests/142 > @@ -96,36 +96,36 @@ function check_cache_all() > # bs->backing > =20 > echo -e "cache.direct=3Don on none0" Pre-existing, but 'echo -e' is non-portable (even in bash, you can set options such that it changes behavior). printf is better, if we're worried about it. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --DmGnNiMIeCFnEGfvqKhHuEV5lj7SHUwsT 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/ iQEcBAEBCAAGBQJW5uvwAAoJEKeha0olJ0NqrbsH/RVI+f81HbpM2528zC22JRtb zInThDsP/GvYjPutdpE/c31UVBcHAzi1fqtXCGxI19feZdVuOTOYbluS7yilbhbA 5nZQrFhjweLhAXezSAnF5g4XynsGQsAD1QNLeWdy5H3DWadwhSWFZljQgNNJAceD SyRjDRElhq8hvPoG7C6Li6Pr4x9zQS0wv5xTqTJvOjaP6+Og+wnDpKB2YTLxY9a9 Ff8pwiKUM9tKvR0KZOAFTeorJ3ie5JfV+UWq41Aiv2BX70X8gjDfZ9G5ZZX7Q9dU cW4v1Hcsinv32ifNHmZ5hd8NzPmgvJ5tFlIPCfGorwmXpsDmeHBIabydSOtwyZs= =KG+h -----END PGP SIGNATURE----- --DmGnNiMIeCFnEGfvqKhHuEV5lj7SHUwsT--