From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34034) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aktwq-0005oL-4g for qemu-devel@nongnu.org; Tue, 29 Mar 2016 09:44:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aktwp-0003FP-7n for qemu-devel@nongnu.org; Tue, 29 Mar 2016 09:44:44 -0400 References: <1459258257-17767-1-git-send-email-kwolf@redhat.com> <1459258257-17767-15-git-send-email-kwolf@redhat.com> From: Max Reitz Message-ID: <56FA86C2.3060807@redhat.com> Date: Tue, 29 Mar 2016 15:44:34 +0200 MIME-Version: 1.0 In-Reply-To: <1459258257-17767-15-git-send-email-kwolf@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="tdG4LCF0a905sBb9qLQ0LWTXQJiduMvqS" Subject: Re: [Qemu-devel] [PATCH v2 14/20] nbd: Support BDRV_REQ_FUA List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf , qemu-block@nongnu.org Cc: qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --tdG4LCF0a905sBb9qLQ0LWTXQJiduMvqS Content-Type: multipart/mixed; boundary="S4qSBTp2oPmLqpH0pNbqujFAg9XjpvTma" From: Max Reitz To: Kevin Wolf , qemu-block@nongnu.org Cc: qemu-devel@nongnu.org Message-ID: <56FA86C2.3060807@redhat.com> Subject: Re: [PATCH v2 14/20] nbd: Support BDRV_REQ_FUA References: <1459258257-17767-1-git-send-email-kwolf@redhat.com> <1459258257-17767-15-git-send-email-kwolf@redhat.com> In-Reply-To: <1459258257-17767-15-git-send-email-kwolf@redhat.com> --S4qSBTp2oPmLqpH0pNbqujFAg9XjpvTma Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: quoted-printable On 29.03.2016 15:30, Kevin Wolf wrote: > The NBD server already used to send a FUA flag when the writethrough > mode was set. This code was a remnant from the times where protocol > drivers actually had to implement writethrough modes. Since nowadays th= e > block layer sends flushes in writethrough mode and non-root nodes are > always writeback, this was mostly dead code - only mostly because if NB= D > was configured to be used without a format, we sent _both_ FUA and an > explicit flush afterwards, which makes the code not technically dead, > but useless overhead. >=20 > This patch changes the code so that the block layer's FUA flag is > recognised and translated into a NBD FUA flag. The additional flush is > avoided now. >=20 > Signed-off-by: Kevin Wolf > --- > block/nbd-client.c | 13 +++++++------ > block/nbd-client.h | 2 +- > block/nbd.c | 27 ++++++++++++++++++++++++++- > 3 files changed, 34 insertions(+), 8 deletions(-) Reviewed-by: Max Reitz --S4qSBTp2oPmLqpH0pNbqujFAg9XjpvTma-- --tdG4LCF0a905sBb9qLQ0LWTXQJiduMvqS 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 iQEcBAEBCAAGBQJW+obCAAoJEDuxQgLoOKyt2soH/216ue7PSfZ7ko4rUY1mhKYz /rCWYEwHDGg8Z/JsO5nNs/QNNUuXvpFQ8jb1yaZ/A0TOGiPBiYDq/qjoM3IAx8l5 YEC2QZV9njmRhDXsaSrT/Ywtf+Pb4TtbQjfCNKA9bNvWfepKzz/aqQM8UdlFuMVk vIo9mfZySXZhN81j0ooiYfNIHBJaHhFwMtliIvf8AxQ9OP31fdkCQwleZPy+BmLl rotGZ4NoFt7U/6It/hx2I3lZsbtc44o+tmady4CQyiQhQZjcwMqtyaGJ9+vd7guu /BzOnVrgA/KtzA59PeIMdQDtnAffpK7+WJ/gotV0iiFhgdaREx+1Bdos3bE3C/E= =xRpP -----END PGP SIGNATURE----- --tdG4LCF0a905sBb9qLQ0LWTXQJiduMvqS--