From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47940) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bm5Ld-0004tK-Qc for qemu-devel@nongnu.org; Mon, 19 Sep 2016 16:39:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bm5Lc-0000Wh-Pp for qemu-devel@nongnu.org; Mon, 19 Sep 2016 16:39:29 -0400 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> From: Eric Blake Message-ID: <31566a2b-bf64-97de-5483-85284c341313@redhat.com> Date: Mon, 19 Sep 2016 15:39:21 -0500 MIME-Version: 1.0 In-Reply-To: <960740fa-37d0-48d5-820f-ebfe8979ffa8@openvz.org> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="LdUsxiKJsR6klRvIjSblqpONJP6k7Eo4C" 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: "Denis V. Lunev" , Fam Zheng Cc: Kevin Wolf , qemu-block@nongnu.org, Jeff Cody , qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --LdUsxiKJsR6klRvIjSblqpONJP6k7Eo4C From: Eric Blake To: "Denis V. Lunev" , Fam Zheng Cc: Kevin Wolf , qemu-block@nongnu.org, Jeff Cody , qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi Message-ID: <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() 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> In-Reply-To: <960740fa-37d0-48d5-820f-ebfe8979ffa8@openvz.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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 i= s >>> 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. I typically write this as: L2 <- L1 <- L0 (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. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --LdUsxiKJsR6klRvIjSblqpONJP6k7Eo4C Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJX4Ez5AAoJEKeha0olJ0NqdP0H/0IVVHHm7vS3+uhQfoiYWIsk PsMsoEcUCcyrS05QaaoUk6U9OqVteWWPTBstixsKu9aFFBjKipnIXDdKPUYgeBAm R7cjcdgWErY551z61wQv3HsJ+kk8H+epYGWjsZf04tEh4nxjyW2pqN6OjtjcL+ip u6sAod0CbpAex/ZMIW7iBkmI+Vx3h2OCSanH7FGxNDUuz77z1Mnw8npPK6eg+kUq oZtpXz1yhecEnIFNzhKTwiPOUKBS0L5xG5DNBu2AFzTT7uynjUQFCxJiRrf2URFX CTrtFK5LCkc/PbwVpZpf5mUIxAOBVmqzxyioL6ZNH60p76FJRMTsVcbtpznLC5U= =Kb0/ -----END PGP SIGNATURE----- --LdUsxiKJsR6klRvIjSblqpONJP6k7Eo4C--