From e8894d66a9c560a8fb72ec94fca58e74fcb6c0e5 Mon Sep 17 00:00:00 2001 From: Max Reitz <mreitz@redhat.com> Date: Wed, 17 Jun 2015 12:42:54 +0200 Subject: [PATCH 012/217] qcow2: Set MIN_L2_CACHE_SIZE to 2 Message-id: <1434544976-15816-2-git-send-email-mreitz@redhat.com> Patchwork-id: 66281 O-Subject: [RHEV-7.2 qemu-kvm-rhev PATCH 1/3] qcow2: Set MIN_L2_CACHE_SIZE to 2 Bugzilla: 1226996 RH-Acked-by: Fam Zheng <famz@redhat.com> RH-Acked-by: Kevin Wolf <kwolf@redhat.com> RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com> BZ: 1226996 The L2 cache must cover at least two L2 tables, because during COW two L2 tables are accessed simultaneously. Reported-by: Alexander Graf <agraf@suse.de> Cc: qemu-stable <qemu-stable@nongnu.org> Signed-off-by: Max Reitz <mreitz@redhat.com> Tested-by: Alexander Graf <agraf@suse.de> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> (cherry picked from commit 57e216695948a79d9ced82fc217a37cce70fd986) Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com> --- block/qcow2.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/qcow2.h b/block/qcow2.h index 422b825..2f20949 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -62,7 +62,8 @@ #define MIN_CLUSTER_BITS 9 #define MAX_CLUSTER_BITS 21 -#define MIN_L2_CACHE_SIZE 1 /* cluster */ +/* Must be at least 2 to cover COW */ +#define MIN_L2_CACHE_SIZE 2 /* clusters */ /* Must be at least 4 to cover all cases of refcount table growth */ #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */ -- 1.8.3.1