From 48ec01bf0d7ad38571741cf9aca816a0bfdddbe0 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Sat, 13 Jun 2015 16:22:10 +0200 Subject: [PATCH 16/42] qcow2: Calculate refcount block entry count Message-id: <1434212556-3927-17-git-send-email-mreitz@redhat.com> Patchwork-id: 66035 O-Subject: [RHEL-7.2 qemu-kvm PATCH 16/42] qcow2: Calculate refcount block entry count Bugzilla: 1129893 RH-Acked-by: Jeffrey Cody RH-Acked-by: Fam Zheng RH-Acked-by: Stefan Hajnoczi BZ: 1129893 The size of a refblock entry is (in theory) variable; calculate therefore the number of entries per refblock and the according bit shift (1 << x == entry count) when opening an image. Signed-off-by: Max Reitz Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf (cherry picked from commit 1d13d654666a7fd6d6a85a0ce9285dbf0d0444c2) Signed-off-by: Max Reitz Signed-off-by: Miroslav Rezanina --- block/qcow2.c | 3 +++ block/qcow2.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/block/qcow2.c b/block/qcow2.c index be7e8e8..fae8b26 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -604,6 +604,9 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ s->l2_size = 1 << s->l2_bits; + /* 2^(s->refcount_order - 3) is the refcount width in bytes */ + s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); + s->refcount_block_size = 1 << s->refcount_block_bits; bs->total_sectors = header.size / 512; s->csize_shift = (62 - (s->cluster_bits - 8)); s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; diff --git a/block/qcow2.h b/block/qcow2.h index 2138462..b65f629 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -213,6 +213,8 @@ typedef struct BDRVQcowState { int l2_size; int l1_size; int l1_vm_state_index; + int refcount_block_bits; + int refcount_block_size; int csize_shift; int csize_mask; uint64_t cluster_offset_mask; -- 1.8.3.1