In check_constraints_on_bitmap(), the sanity check on the granularity will cause uint64_t integer left-shift overflow when cluster_size is 2M and the granularity is BIGGER than 32K. As a result, for a qcow2 disk with cluster_size set to 2M, we could not even create a dirty bitmap with default granularity. This patch fix the issue by dividing @len by granularity instead.
Signed-off-by: Guoyi Tu <[email protected]> --- block/qcow2-bitmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index 98294a7..71ac822 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -172,8 +172,8 @@ static int check_constraints_on_bitmap(BlockDriverState *bs, } if ((len > (uint64_t)BME_MAX_PHYS_SIZE << granularity_bits) || - (len > (uint64_t)BME_MAX_TABLE_SIZE * s->cluster_size << - granularity_bits)) + (DIV_ROUND_UP(len, granularity) > (uint64_t)BME_MAX_TABLE_SIZE * + s->cluster_size)) { error_setg(errp, "Too much space will be occupied by the bitmap. " "Use larger granularity"); -- 2.7.4
