From bb56d89a4b39e5764f3b7b422eb79db636ebb9e1 Mon Sep 17 00:00:00 2001 Message-Id: In-Reply-To: <67968bc615637394c3ef7dfefa360dab90f33d5d.1429902956.git.jen@redhat.com> References: <67968bc615637394c3ef7dfefa360dab90f33d5d.1429902956.git.jen@redhat.com> From: Max Reitz Date: Wed, 18 Mar 2015 19:21:49 -0500 Subject: [CHANGE 06/42] qcow2: Simplify count_cow_clusters To: rhvirt-patches@redhat.com, jen@redhat.com RH-Author: Max Reitz Message-id: <1426706542-30384-7-git-send-email-mreitz@redhat.com> Patchwork-id: 64470 O-Subject: [RHEL-6.7 qemu-kvm PATCH v2 06/39] qcow2: Simplify count_cow_clusters Bugzilla: 1129892 RH-Acked-by: Jeffrey Cody RH-Acked-by: Kevin Wolf RH-Acked-by: Stefan Hajnoczi From: Kevin Wolf BZ: 1129892 count_cow_clusters() tries to reuse existing functions, and all it achieves is to make things much more complicated than they really are: Everything needs COW, unless it's a normal cluster with refcount 1. This patch implements the obvious way of doing this, and by using qcow2_get_cluster_type() it gets rid of all flag magic. Signed-off-by: Kevin Wolf (cherry picked from commit 143550a83ef4eef86a847d00023d148e1f59f743) Signed-off-by: Max Reitz --- block/qcow2-cluster.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) Signed-off-by: Jeff E. Nelson --- block/qcow2-cluster.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index f973b54..73c9bf3 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -751,30 +751,27 @@ err: static int count_cow_clusters(BDRVQcowState *s, int nb_clusters, uint64_t *l2_table, int l2_index) { - int i = 0; - uint64_t cluster_offset; + int i; - while (i < nb_clusters) { - i += count_contiguous_clusters(nb_clusters - i, s->cluster_size, - &l2_table[l2_index], i, - QCOW_OFLAG_COPIED | QCOW_OFLAG_COMPRESSED); - if ((i >= nb_clusters) || be64_to_cpu(l2_table[l2_index + i])) { - break; - } + for (i = 0; i < nb_clusters; i++) { + uint64_t l2_entry = be64_to_cpu(l2_table[l2_index + i]); + int cluster_type = qcow2_get_cluster_type(l2_entry); - i += count_contiguous_free_clusters(nb_clusters - i, - &l2_table[l2_index + i]); - if (i >= nb_clusters) { + switch(cluster_type) { + case QCOW2_CLUSTER_NORMAL: + if (l2_entry & QCOW_OFLAG_COPIED) { + goto out; + } break; - } - - cluster_offset = be64_to_cpu(l2_table[l2_index + i]); - - if ((cluster_offset & QCOW_OFLAG_COPIED) || - (cluster_offset & QCOW_OFLAG_COMPRESSED)) + case QCOW2_CLUSTER_UNALLOCATED: + case QCOW2_CLUSTER_COMPRESSED: break; + default: + abort(); + } } +out: assert(i <= nb_clusters); return i; } -- 2.1.0