From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40340) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1egWpT-0003Nr-Pl for qemu-devel@nongnu.org; Tue, 30 Jan 2018 09:24:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1egWpS-0004L4-MR for qemu-devel@nongnu.org; Tue, 30 Jan 2018 09:24:07 -0500 References: <20180130063433.11605-1-famz@redhat.com> <20180130063433.11605-3-famz@redhat.com> From: Eric Blake Message-ID: Date: Tue, 30 Jan 2018 08:23:50 -0600 MIME-Version: 1.0 In-Reply-To: <20180130063433.11605-3-famz@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="WUNwFtCXauQTSBBJGMDpgqY9TBWaJzhmV" Subject: Re: [Qemu-devel] [PATCH v6 2/2] qemu-img: Document --force-share / -U List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng , qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, stefanha@redhat.com, kchamart@redhat.com, Kevin Wolf , Max Reitz This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --WUNwFtCXauQTSBBJGMDpgqY9TBWaJzhmV From: Eric Blake To: Fam Zheng , qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, stefanha@redhat.com, kchamart@redhat.com, Kevin Wolf , Max Reitz Message-ID: Subject: Re: [PATCH v6 2/2] qemu-img: Document --force-share / -U References: <20180130063433.11605-1-famz@redhat.com> <20180130063433.11605-3-famz@redhat.com> In-Reply-To: <20180130063433.11605-3-famz@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 01/30/2018 12:34 AM, Fam Zheng wrote: > Signed-off-by: Fam Zheng > Signed-off-by: Kevin Wolf > --- > qemu-img.texi | 7 +++++++ > 1 file changed, 7 insertions(+) >=20 > diff --git a/qemu-img.texi b/qemu-img.texi > index 60a0e080c6..ec7e2f5d1e 100644 > --- a/qemu-img.texi > +++ b/qemu-img.texi > @@ -86,6 +86,13 @@ exclusive with the @var{-O} parameters. It is curren= tly required to also use > the @var{-n} parameter to skip image creation. This restriction may be= relaxed > in a future release. > =20 > +@item --force-share (-U) > +If specified, @code{qemu-img} will open the image in shared mode, allo= wing > +concurrent writers. For example, this can be used to get the image inf= ormation Actually, we only permit one writer at a time. Would it be better to say "allowing a concurrent writer"? > +(with 'info' subcommand) when the image is used by a running guest. N= ote that > +this could produce inconsistent results because of concurrent metadata= changes, > +etc. This option is only allowed when opening images in read-only mode= =2E After all, we are stating that this process (which must be read-only, because we can't have two writers at once) is permitting some other process to be the concurrent writer (but not multiple processes to be concurrent writers) --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org --WUNwFtCXauQTSBBJGMDpgqY9TBWaJzhmV Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAlpwf/YACgkQp6FrSiUn Q2oxnAf/ZCvE5GvLfGRSmubHEYbBG7QjAnZR5YaUcvO3m2Wl8wj9nUL4ziWc64UA HMdLOgJPxIgcg/GCpA+S/h1u1+wPq5rPGlWjvPdWhbCNFrip22lUbGLpyraXK+uw QGD5clqelReyL1g4qSBWnHKRCO1BMY9OcMAQ/ocFv5raOPPEu0inZyrZmTRwi/Sq RB6ShKfk9HlENeWe9KFcXzAgueB+BUT2VvNJNQzH4bdPWJcHyeYooAIc/HWG7vQp Cn5Zy2fV5Yv+mneoYalNq06dD18OyrTQM43cz0+yH6j6xPyOfx4e6P+rQapDlnOS /E1gnz43a6ibaDAC/ouZL8fSC40brg== =gik3 -----END PGP SIGNATURE----- --WUNwFtCXauQTSBBJGMDpgqY9TBWaJzhmV--