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Fri, 14 Jun 2019 16:20:35 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" References: <20190612221004.2317-1-mreitz@redhat.com> <20190612221004.2317-24-mreitz@redhat.com> <112404e2-7172-865c-d888-6a5cddcc40ec@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: Date: Fri, 14 Jun 2019 18:20:34 +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: <112404e2-7172-865c-d888-6a5cddcc40ec@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="h25BM4vX1gPZdo2nXDB4lUa9nWejHvTVm" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Fri, 14 Jun 2019 16:20:37 +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 23/42] blockdev: Use CAF in external_snapshot_prepare() 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) --h25BM4vX1gPZdo2nXDB4lUa9nWejHvTVm Content-Type: multipart/mixed; boundary="VEvUOPgC60sSQnGcsmicAht7c0zIUlogt"; protected-headers="v1" From: Max Reitz To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" Cc: "qemu-devel@nongnu.org" , Kevin Wolf Message-ID: Subject: Re: [PATCH v5 23/42] blockdev: Use CAF in external_snapshot_prepare() References: <20190612221004.2317-1-mreitz@redhat.com> <20190612221004.2317-24-mreitz@redhat.com> <112404e2-7172-865c-d888-6a5cddcc40ec@virtuozzo.com> In-Reply-To: <112404e2-7172-865c-d888-6a5cddcc40ec@virtuozzo.com> --VEvUOPgC60sSQnGcsmicAht7c0zIUlogt Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 14.06.19 17:46, Vladimir Sementsov-Ogievskiy wrote: > 13.06.2019 1:09, Max Reitz wrote: >> This allows us to differentiate between filters and nodes with COW >> backing files: Filters cannot be used as overlays at all (for this >> function). >> >> Signed-off-by: Max Reitz >=20 > Overlay created in snapshot operation assumed to consume following writ= es > and it's filtered child becomes readonly.. And filter works in complete= ly another > way. >=20 > Reviewed-by: Vladimir Sementsov-Ogievskiy >=20 > [hmm, I start to like using "filtered child" collocation when I say abo= ut this thing. > didn't you think about renaming backing chain to filtered chain?] Hm. There are backing chains and there are backing chains. There are qemu-internal backing chains that consist of a healthy mix of filters and COW overlays, and then there are the more high-level backing chains the user actually manages, where only the overlays are important. I think it would make sense to rename the =E2=80=9Cqemu-internal backing = chains" to =E2=80=9Cfilter chains=E2=80=9D or something. But that makes it sound= a bit like it would only mean R/W filters... Maybe just =E2=80=9Cchain=E2=80=9D? Actually, the only functions I find are is_backing_chain_frozen & Co, and they could simply become is_chain_frozen. Is there anything else? Max --VEvUOPgC60sSQnGcsmicAht7c0zIUlogt-- --h25BM4vX1gPZdo2nXDB4lUa9nWejHvTVm Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl0DyVIACgkQ9AfbAGHV z0CcOgf/U7VLnHaEaio1ibSs7Ygccs9Mb5AKSVYyeFr+QGvnKapcVyyaVj/v9SvX oGKjYMLR1rvcWXGwaEM/gO0CjggqV5eU8RCFzWULvW48iaKFyvhV17LEfPcblGl7 nh8wAw+ugVYfgDPdCKjD533VvjAPqB8BfT4onFOECJNGELgWO8a/gkrD8rW0SD0f mQafgiTUHIN+uHEa/jpdCRhLENHhkSlxY6ZSbpaQILq/m58P2k9zVNNaieqvS0Cz 5CmuuX5NXGOO+wGS/l/GeNVm1aMdgIcaWhZLsVjJ7UABFKyP4oBc5RjdExk5jEJ2 qgYM76Z8eunuEuVdH1Y9kz4NldpWiA== =7gf+ -----END PGP SIGNATURE----- --h25BM4vX1gPZdo2nXDB4lUa9nWejHvTVm--