From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60014) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eFi9z-00026J-KL for qemu-devel@nongnu.org; Fri, 17 Nov 2017 10:02:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eFi9q-00048A-5M for qemu-devel@nongnu.org; Fri, 17 Nov 2017 10:02:27 -0500 References: <20171023092945.54532-1-vsementsov@virtuozzo.com> <20171117123059.GB4795@localhost.localdomain> From: Max Reitz Message-ID: Date: Fri, 17 Nov 2017 16:01:56 +0100 MIME-Version: 1.0 In-Reply-To: <20171117123059.GB4795@localhost.localdomain> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="8d1EGbFmIvtbWs1Exxia2J1wpDtCRGUtH" Subject: Re: [Qemu-devel] [PATCH] block/snapshot: dirty all dirty bitmaps on snapshot-switch List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf , Vladimir Sementsov-Ogievskiy Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, eblake@redhat.com, jsnow@redhat.com, famz@redhat.com, den@openvz.org, stefanha@redhat.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --8d1EGbFmIvtbWs1Exxia2J1wpDtCRGUtH From: Max Reitz To: Kevin Wolf , Vladimir Sementsov-Ogievskiy Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, eblake@redhat.com, jsnow@redhat.com, famz@redhat.com, den@openvz.org, stefanha@redhat.com Message-ID: Subject: Re: [PATCH] block/snapshot: dirty all dirty bitmaps on snapshot-switch References: <20171023092945.54532-1-vsementsov@virtuozzo.com> <20171117123059.GB4795@localhost.localdomain> In-Reply-To: <20171117123059.GB4795@localhost.localdomain> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 2017-11-17 13:30, Kevin Wolf wrote: > Am 23.10.2017 um 11:29 hat Vladimir Sementsov-Ogievskiy geschrieben: >> Snapshot-switch actually changes active state of disk so it should >> reflect on dirty bitmaps. Otherwise next incremental backup using >> these bitmaps will be invalid. >> >> Signed-off-by: Vladimir Sementsov-Ogievskiy = >=20 > We discussed this quite a while ago, and I'm still not convinced that > this approach makes sense. I think it at least makes more sense than not handling this case at all. > Can you give just one example of a use case where dirtying the whole > bitmap while loading a snapshot is the desired behaviour? >=20 > I think the most useful behaviour would be something where the bitmaps > themselves are snapshotted, too. Agreed. > But for the time being, the easiest an= d > safest solution might just be to error out in any snapshot operations > if any bitmaps are in use. Sounds OK, too. I personally don't have an opinion either way. But in any case, what we did before this patch was definitely wrong so I consider it an improvement. Max --8d1EGbFmIvtbWs1Exxia2J1wpDtCRGUtH Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQFGBAEBCAAwFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAloO+eQSHG1yZWl0ekBy ZWRoYXQuY29tAAoJEPQH2wBh1c9AlgoIAKOKOq/v0mGsXHa3JqDbSmfrkJI/yASc z7AxmA1UCsVNyNk0M7RGjs3I5o3LNXWZdyOzXpW9ZQju1B3O0ZUSZ9JVSuCqfy42 WTNp/yVWECqynoRUeTSY3hWvYXbM64tOrX+OK7kDCIL+3i2jP5HwOBqDKBOtdNmL InEfoHnN01GJPz8vTsiB9FN1wbYSD+GKHHPslTP871vz1e3xYZwwA1WqJDt2ebWK yO8/KGO9VpkyZ8MuzAxFubFqX8B1QMsJJu+XNuYZBdt6Auh5CLhho7NQGpXxbQRQ +W8qagIVgouhqzEaaPydWVQ65bN3wpqmzhEi0petMp1RMC8hcn30DGI= =3uaP -----END PGP SIGNATURE----- --8d1EGbFmIvtbWs1Exxia2J1wpDtCRGUtH--