From 1d13d654666a7fd6d6a85a0ce9285dbf0d0444c2 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Wed, 22 Oct 2014 14:09:28 +0200 Subject: qcow2: Calculate refcount block entry count 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 --- block/qcow2.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'block/qcow2.c') diff --git a/block/qcow2.c b/block/qcow2.c index 156a219993..3c8b88198b 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -698,6 +698,9 @@ 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; -- cgit v1.2.3