From patchwork Thu Mar 28 16:40:32 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 232141 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 7E7D42C00BC for ; Fri, 29 Mar 2013 04:23:56 +1100 (EST) Received: from localhost ([::1]:44823 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ULFzR-0006bh-B1 for incoming@patchwork.ozlabs.org; Thu, 28 Mar 2013 12:47:49 -0400 Received: from eggs.gnu.org ([208.118.235.92]:46647) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ULFtH-0006Ag-B7 for qemu-devel@nongnu.org; Thu, 28 Mar 2013 12:41:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ULFtD-0002Hf-Vr for qemu-devel@nongnu.org; Thu, 28 Mar 2013 12:41:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39310) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ULFtD-0002HS-NH for qemu-devel@nongnu.org; Thu, 28 Mar 2013 12:41:23 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r2SGfMfc015910 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 28 Mar 2013 12:41:23 -0400 Received: from localhost (ovpn-112-23.ams2.redhat.com [10.36.112.23]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r2SGfLJh019847; Thu, 28 Mar 2013 12:41:22 -0400 From: Stefan Hajnoczi To: Date: Thu, 28 Mar 2013 17:40:32 +0100 Message-Id: <1364488837-15916-19-git-send-email-stefanha@redhat.com> In-Reply-To: <1364488837-15916-1-git-send-email-stefanha@redhat.com> References: <1364488837-15916-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.25 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Kevin Wolf , Anthony Liguori , Stefan Hajnoczi Subject: [Qemu-devel] [PATCH 18/23] qcow2: Prepare handle_alloc/copied() for byte granularity X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Kevin Wolf This makes handle_alloc() and handle_copied() return byte-granularity host offsets instead of returning always the cluster start. This is required so that qcow2_alloc_cluster_offset() can stop aligning everything to cluster boundaries. Signed-off-by: Kevin Wolf Signed-off-by: Stefan Hajnoczi --- block/qcow2-cluster.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 239a997..4f43d41 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -817,7 +817,9 @@ static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset, * *host_offset is not zero, only physically contiguous clusters beginning at * this host offset are counted. * - * Note that guest_offset may not be cluster aligned. + * Note that guest_offset may not be cluster aligned. In this case, the + * returned *host_offset points to exact byte referenced by guest_offset and + * therefore isn't cluster aligned as well. * * Returns: * 0: if no allocated clusters are available at the given offset. @@ -845,6 +847,9 @@ static int handle_copied(BlockDriverState *bs, uint64_t guest_offset, trace_qcow2_handle_copied(qemu_coroutine_self(), guest_offset, *host_offset, *bytes); + assert(*host_offset == 0 || offset_into_cluster(s, guest_offset) + == offset_into_cluster(s, *host_offset)); + /* * Calculate the number of clusters to look for. We stop at L2 table * boundaries to keep things simple. @@ -903,7 +908,8 @@ out: /* Only return a host offset if we actually made progress. Otherwise we * would make requirements for handle_alloc() that it can't fulfill */ if (ret) { - *host_offset = cluster_offset & L2E_OFFSET_MASK; + *host_offset = (cluster_offset & L2E_OFFSET_MASK) + + offset_into_cluster(s, guest_offset); } return ret; @@ -961,7 +967,9 @@ static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset, * copy on write. If *host_offset is non-zero, clusters are only allocated if * the new allocation can match the specified host offset. * - * Note that guest_offset may not be cluster aligned. + * Note that guest_offset may not be cluster aligned. In this case, the + * returned *host_offset points to exact byte referenced by guest_offset and + * therefore isn't cluster aligned as well. * * Returns: * 0: if no clusters could be allocated. *bytes is set to 0, @@ -1026,7 +1034,7 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset, } /* Allocate, if necessary at a given offset in the image file */ - alloc_cluster_offset = *host_offset; + alloc_cluster_offset = start_of_cluster(s, *host_offset); ret = do_alloc_cluster_offset(bs, guest_offset, &alloc_cluster_offset, &nb_clusters); if (ret < 0) { @@ -1062,12 +1070,10 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset, >> BDRV_SECTOR_BITS; int nb_sectors = MIN(requested_sectors, avail_sectors); - *host_offset = alloc_cluster_offset; - *m = g_malloc0(sizeof(**m)); **m = (QCowL2Meta) { - .alloc_offset = *host_offset, + .alloc_offset = alloc_cluster_offset, .offset = start_of_cluster(s, guest_offset), .nb_clusters = nb_clusters, .nb_available = nb_sectors, @@ -1084,6 +1090,7 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset, qemu_co_queue_init(&(*m)->dependent_requests); QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight); + *host_offset = alloc_cluster_offset + offset_into_cluster(s, guest_offset); *bytes = MIN(*bytes, (nb_sectors * BDRV_SECTOR_SIZE) - offset_into_cluster(s, guest_offset)); assert(*bytes != 0); @@ -1186,7 +1193,7 @@ again: nb_clusters -= keep_clusters; if (!*host_offset) { - *host_offset = cluster_offset; + *host_offset = start_of_cluster(s, cluster_offset); } } else if (cur_bytes == 0) { keep_clusters = 0; @@ -1228,7 +1235,7 @@ again: } if (!*host_offset) { - *host_offset = cluster_offset; + *host_offset = start_of_cluster(s, cluster_offset); } nb_clusters = size_to_clusters(s, cur_bytes + offset_into_cluster(s, offset));