From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38002) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1boXSM-0001bI-Mc for qemu-devel@nongnu.org; Mon, 26 Sep 2016 11:04:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1boXSK-0004Uu-Mg for qemu-devel@nongnu.org; Mon, 26 Sep 2016 11:04:33 -0400 Date: Mon, 26 Sep 2016 17:04:21 +0200 From: Kevin Wolf Message-ID: <20160926150421.GL6093@noname.str.redhat.com> References: <1473957290-13382-1-git-send-email-den@openvz.org> <1473957290-13382-2-git-send-email-den@openvz.org> <20160919012151.GA4883@lemon> <960740fa-37d0-48d5-820f-ebfe8979ffa8@openvz.org> <31566a2b-bf64-97de-5483-85284c341313@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3uo+9/B/ebqu+fSQ" Content-Disposition: inline In-Reply-To: <31566a2b-bf64-97de-5483-85284c341313@redhat.com> Subject: Re: [Qemu-devel] [PATCH v3 1/2] block: sync bdrv_co_get_block_status_above() with bdrv_is_allocated_above() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: "Denis V. Lunev" , Fam Zheng , qemu-block@nongnu.org, Jeff Cody , qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi --3uo+9/B/ebqu+fSQ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Am 19.09.2016 um 22:39 hat Eric Blake geschrieben: > On 09/18/2016 11:37 PM, Denis V. Lunev wrote: > > On 09/19/2016 04:21 AM, Fam Zheng wrote: > >> On Thu, 09/15 19:34, Denis V. Lunev wrote: > >>> They should work very similar, covering same areas if backing store is > >>> shorter than the image. This change is necessary for the followup pat= ch > >>> switching to bdrv_get_block_status_above() in mirror to avoid assert > >>> in check_block. > >>> > >>> This change should be made very carefully. Let us assume that we have > >>> top image and 2 backing stores L0->L1->L2. > >> Stupid question: which one is top and which are backing? > > L0 is top, L2 is at bottom. >=20 > I typically write this as: >=20 > L2 <- L1 <- L0 >=20 > (read "L2 backs L1, which in turn backs L0") with the active on the > right. So I understand the confusion in Fam's question where you were > using the opposite direction. And I tend to use this one: base <- sn1 <- sn2 <- top "sn*" isn't any better than "L*", but having at least one of "base" and "top" (or "active") in there disambiguates the roles of the nodes. Kevin --3uo+9/B/ebqu+fSQ Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJX6Tj1AAoJEH8JsnLIjy/W2UEP/2cquLquqbtQvKz6JxGjGH5E CaxS9kg96+Ah+u6G6M6/Z98ft9MBH675xydiYY3jc8tHO5N/hDlevkb+i8ShO74W MFVvrnZtL1ex8wI64kAhzJeDOuIADdW7PFCvOhZNbgYz6iCYr1aPKWKuwltefENR oEx2E/g81IkBHMlHaM7kTlTcOc3qKXtiEEtItNsx3MV6FRI19Svl+8HwzXqyGioW Gde8NYXig74JUurY3RlPLhSJxev4cjIMb9uglyyJSK93eAkc0YW4KLgZ3YOSS2d7 t32tFt7WxFVBo636X78NRhPhj2q1NGCMOquD2W6lBsce3/KneKvYMapdYq7lJA4D lfdO7Tz8uqTR+Pjng86cs7NOGB2H2or9PR1ziTahmS4L5Z6s9pmodF2TpLuSb1Bs c35FmxvLht3bzNMQKAKn1p3vpSOSuyxZHwr57BnDEu7KSgNRR2eJAImDKQrbVOrx l9gLbztiFL8pGCMnxyDzVI8PB26j7e4xsfV2blk/39nPpV95wAqqT9bWtG8JPbTx RKKhNO7IzBDzLchHnp2PSZWXEq4cUREd3XQlpgZu+ED9wfC56kczjQFZ1CR1bts3 L0LLEQeQn/GCV+y1BDULVfDjEPKhqREvS+5lgzfEZqqmdB5GgOx3u2rNTWtS5xAf 8SF2uhBBMj16L6tPlcr1 =aYIv -----END PGP SIGNATURE----- --3uo+9/B/ebqu+fSQ--