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Thu, 13 Jun 2019 16:12:09 +0000 (UTC) Received: from dresden.str.redhat.com (unknown [10.40.205.187]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 292335C29A; Thu, 13 Jun 2019 16:12:07 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" References: <20190612221004.2317-1-mreitz@redhat.com> <4c6524b7-2feb-2b92-6929-54629ece1e29@virtuozzo.com> From: Max Reitz Openpgp: preference=signencrypt Autocrypt: addr=mreitz@redhat.com; prefer-encrypt=mutual; keydata= mQENBFXOJlcBCADEyyhOTsoa/2ujoTRAJj4MKA21dkxxELVj3cuILpLTmtachWj7QW+TVG8U /PsMCFbpwsQR7oEy8eHHZwuGQsNpEtNC2G/L8Yka0BIBzv7dEgrPzIu+W3anZXQW4702+uES U29G8TP/NGfXRRHGlbBIH9KNUnOSUD2vRtpOLXkWsV5CN6vQFYgQfFvmp5ZpPeUe6xNplu8V mcTw8OSEDW/ZnxJc8TekCKZSpdzYoxfzjm7xGmZqB18VFwgJZlIibt1HE0EB4w5GsD7x5ekh awIe3RwoZgZDLQMdOitJ1tUc8aqaxvgA4tz6J6st8D8pS//m1gAoYJWGwwIVj1DjTYLtABEB AAG0HU1heCBSZWl0eiA8bXJlaXR6QHJlZGhhdC5jb20+iQFTBBMBCAA9AhsDBQkSzAMABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheABQJVzie5FRhoa3A6Ly9rZXlzLmdudXBnLm5ldAAKCRD0 B9sAYdXPQDcIB/9uNkbYEex1rHKz3mr12uxYMwLOOFY9fstP5aoVJQ1nWQVB6m2cfKGdcRe1 2/nFaHSNAzT0NnKz2MjhZVmcrpyd2Gp2QyISCfb1FbT82GMtXFj1wiHmPb3CixYmWGQUUh+I AvUqsevLA+WihgBUyaJq/vuDVM1/K9Un+w+Tz5vpeMidlIsTYhcsMhn0L9wlCjoucljvbDy/ 8C9L2DUdgi3XTa0ORKeflUhdL4gucWoAMrKX2nmPjBMKLgU7WLBc8AtV+84b9OWFML6NEyo4 4cP7cM/07VlJK53pqNg5cHtnWwjHcbpGkQvx6RUx6F1My3y52vM24rNUA3+ligVEgPYBuQEN BFXOJlcBCADAmcVUNTWT6yLWQHvxZ0o47KCP8OcLqD+67T0RCe6d0LP8GsWtrJdeDIQk+T+F xO7DolQPS6iQ6Ak2/lJaPX8L0BkEAiMuLCKFU6Bn3lFOkrQeKp3u05wCSV1iKnhg0UPji9V2 W5eNfy8F4ZQHpeGUGy+liGXlxqkeRVhLyevUqfU0WgNqAJpfhHSGpBgihUupmyUg7lfUPeRM DzAN1pIqoFuxnN+BRHdAecpsLcbR8sQddXmDg9BpSKozO/JyBmaS1RlquI8HERQoe6EynJhd 64aICHDfj61rp+/0jTIcevxIIAzW70IadoS/y3DVIkuhncgDBvGbF3aBtjrJVP+5ABEBAAGJ ASUEGAEIAA8FAlXOJlcCGwwFCRLMAwAACgkQ9AfbAGHVz0CbFwf9F/PXxQR9i4N0iipISYjU sxVdjJOM2TMut+ZZcQ6NSMvhZ0ogQxJ+iEQ5OjnIputKvPVd5U7WRh+4lF1lB/NQGrGZQ1ic alkj6ocscQyFwfib+xIe9w8TG1CVGkII7+TbS5pXHRxZH1niaRpoi/hYtgzkuOPp35jJyqT/ /ELbqQTDAWcqtJhzxKLE/ugcOMK520dJDeb6x2xVES+S5LXby0D4juZlvUj+1fwZu+7Io5+B bkhSVPb/QdOVTpnz7zWNyNw+OONo1aBUKkhq2UIByYXgORPFnbfMY7QWHcjpBVw9MgC4tGeF R4bv+1nAMMxKmb5VvQCExr0eFhJUAHAhVg== Message-ID: <25f94c28-0f03-f2dc-9a26-314af8d0937f@redhat.com> Date: Thu, 13 Jun 2019 18:12:06 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <4c6524b7-2feb-2b92-6929-54629ece1e29@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="F0sGjpUmDV4JYDZEXBJCt1l6gZmvpwWAi" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Thu, 13 Jun 2019 16:12:09 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v5 00/42] block: Deal with filters X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , "qemu-devel@nongnu.org" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --F0sGjpUmDV4JYDZEXBJCt1l6gZmvpwWAi Content-Type: multipart/mixed; boundary="akisZMwe7H8xHkd8U3UKV2NwnzOfMQWi5"; protected-headers="v1" From: Max Reitz To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" Cc: "qemu-devel@nongnu.org" , Kevin Wolf Message-ID: <25f94c28-0f03-f2dc-9a26-314af8d0937f@redhat.com> Subject: Re: [PATCH v5 00/42] block: Deal with filters References: <20190612221004.2317-1-mreitz@redhat.com> <4c6524b7-2feb-2b92-6929-54629ece1e29@virtuozzo.com> In-Reply-To: <4c6524b7-2feb-2b92-6929-54629ece1e29@virtuozzo.com> --akisZMwe7H8xHkd8U3UKV2NwnzOfMQWi5 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 13.06.19 17:28, Vladimir Sementsov-Ogievskiy wrote: > 13.06.2019 1:09, Max Reitz wrote: >> Hi, >> >> When we introduced filters, we did it a bit casually. Sure, we talked= a >> lot about them before, but that was mostly discussion about where >> implicit filters should be added to the graph (note that we currently >> only have two implicit filters, those being mirror and commit). But i= n >> the end, we really just designated some drivers filters (Quorum, >> blkdebug, etc.) and added some specifically (throttle, COR), without >> really looking through the block layer to see where issues might occur= =2E >> >> It turns out vast areas of the block layer just don=E2=80=99t know abo= ut filters >> and cannot really handle them. Many cases will work in practice, in >> others, well, too bad, you cannot use some feature because some part >> deep inside the block layer looks at your filters and thinks they are >> format nodes. >> >> This is one reason why this series is needed. Over time (since v1), a= >> second reason has made its way in: >> >> bs->file is not necessarily the place where a node=E2=80=99s data is s= tored. >> qcow2 now has external data files, and currently there is no way for t= he >> general block layer to know that the data is not stored in bs->file. >> Right now, I do not think that has any real consequences (all function= s >> that need access to the actual data storage file should only do so as = a >> fallback if the driver does not provide some functionality, but qcow2 >> should provide it all), but it still shows that we need some way to le= t >> the general block layer know about such data files. (Also, I will nee= d >> this for v1 of my =E2=80=9CInquire images=E2=80=99 rotational info=E2=80= =9D series.) >> >> I won=E2=80=99t go on and on about this series now, I think the patche= s pretty >> much speak for themselves now. If the cover letter gets too long, >> nobody reads it anyway (see previous versions). >> >> >> *** This series depends on some others. *** >> >> Dependencies: >> - [PATCH 0/4] block: Keep track of parent quiescing >> - [PATCH 0/2] vl: Drain before (block) job cancel when quitting >> - [PATCH v2 0/2] blockdev: Overlays are not snapshots >> >> Based-on: <20190605161118.14544-1-mreitz@redhat.com> >> Based-on: <20190612220839.1374-1-mreitz@redhat.com> >> Based-on: <20190603202236.1342-1-mreitz@redhat.com> >=20 > Could you please export a branch? Sure: https://git.xanclic.moe/XanClic/qemu child-access-functions-v5 Or: https://github.com/XanClic/qemu child-access-functions-v5 (And the base branch is: https://git.xanclic.moe/XanClic/qemu child-access-functions-base https://github.com/XanClic/qemu child-access-functions-base ) >> v5: >> - Split the huge patches 2 and 3 from the previous version into many >> smaller patches to maintain the potential reviewers=E2=80=99 sanity= [Vladimir] >=20 > Thank you! In spite of frightening amount of patches, reviewing became = a lot > simpler. I had hoped making it exactly 42 patches would make it a bit more welcomi= ng. Again, thanks a lot for reviewing! Max --akisZMwe7H8xHkd8U3UKV2NwnzOfMQWi5-- --F0sGjpUmDV4JYDZEXBJCt1l6gZmvpwWAi Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl0CddYACgkQ9AfbAGHV z0BZ0gf+KIjoyUTV01nLvD5wquA6Jh4OVIuwSkN/XUFghDRt18BwbBCciXKDgTiX j4W8B6lL3kPvyouUFoTNRpT7ion96zfARuVWWBN4yBNNIXlTM3/DI1oERJY4zVxF Ypl6HJfKxuAFbsxEFueXI82hVUHQTyNk+ftRhDKvUC7fH8rSvjrANOM0FvjJO/jH OpNreil7QD48Kp7IxFcJbVfqfe/DBQwmow6jl+BHxyFgRnlVjf7xGqWAHGWf5CNr jqx3d3dsx8xGtKCsGKACtY1uGysXqaHbLTULmRbSzb41q4xh1LIn7Z5onXX+aDGT N3M2Y2R8ADY4np5ZBd13zELihlFcNQ== =2SSg -----END PGP SIGNATURE----- --F0sGjpUmDV4JYDZEXBJCt1l6gZmvpwWAi--