From 05b5b6ee54cf69e7053c73286aac354be754235e Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Mon, 5 Feb 2018 16:33:12 +0200 Subject: [PATCH] qcow2: Add offset_to_l1_index() Similar to offset_to_l2_index(), this function returns the index in the L1 table for a given guest offset. This is only used in a couple of places and it's not a particularly complex calculation, but it makes the code a bit more readable. Although in the qcow2_get_cluster_offset() case the old code was taking advantage of the l1_bits variable, we're going to get rid of the other uses of l1_bits in a later patch anyway, so it doesn't make sense to keep it just for this. Signed-off-by: Alberto Garcia Reviewed-by: Eric Blake Reviewed-by: Max Reitz Message-id: a5f626fed526b7459a0425fad06d823d18df8522.1517840877.git.berto@igalia.com Signed-off-by: Max Reitz --- block/qcow2-cluster.c | 4 ++-- block/qcow2.h | 5 +++++ 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index ab5715c97e..ce7591dc3d 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -540,7 +540,7 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, /* seek to the l2 offset in the l1 table */ - l1_index = offset >> l1_bits; + l1_index = offset_to_l1_index(s, offset); if (l1_index >= s->l1_size) { type = QCOW2_CLUSTER_UNALLOCATED; goto out; @@ -663,7 +663,7 @@ static int get_cluster_table(BlockDriverState *bs, uint64_t offset, /* seek to the l2 offset in the l1 table */ - l1_index = offset >> (s->l2_bits + s->cluster_bits); + l1_index = offset_to_l1_index(s, offset); if (l1_index >= s->l1_size) { ret = qcow2_grow_l1_table(bs, l1_index + 1, false); if (ret < 0) { diff --git a/block/qcow2.h b/block/qcow2.h index edc5d8d57d..d9ba57c030 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -463,6 +463,11 @@ static inline int64_t size_to_l1(BDRVQcow2State *s, int64_t size) return (size + (1ULL << shift) - 1) >> shift; } +static inline int offset_to_l1_index(BDRVQcow2State *s, uint64_t offset) +{ + return offset >> (s->l2_bits + s->cluster_bits); +} + static inline int offset_to_l2_index(BDRVQcow2State *s, int64_t offset) { return (offset >> s->cluster_bits) & (s->l2_size - 1);