On Tue 14 Nov 2017 04:27:56 PM CET, Max Reitz wrote:
>>> +static int64_t get_refblock_offset(BlockDriverState *bs, uint64_t offset)
>>> +{
>>> + BDRVQcow2State *s = bs->opaque;
>>> + uint32_t index = offset_to_reftable_index(s, offset);
>>> + int64_t covering_refblock_offset = 0;
>>> +
>>> + if (index < s->refcount_table_size) {
>>> + covering_refblock_offset = s->refcount_table[index] &
>>> REFT_OFFSET_MASK;
>>> + }
>>> + if (!covering_refblock_offset) {
>>> + qcow2_signal_corruption(bs, true, -1, -1, "Refblock at %#" PRIx64
>>> " is "
>>> + "not covered by the refcount structures",
>>> + offset);
>>> + return -EIO;
>>> + }
>>> +
>>> + return covering_refblock_offset;
>>> +}
>>
>> Isn't it simpler to do something like this instead?
>>
>> if (index >= s->refcount_table_size) {
>> qcow2_signal_corruption(...);
>> return -EIO;
>> }
>> return s->refcount_table[index] & REFT_OFFSET_MASK;
>
> But that doesn't cover the case were s->refcount_table[index] &
> REFT_OFFSET_MASK is 0.
Ah, you're right. That would be detected by the qcow2_cache_get() call
though, but it's fine to do the check here as well.
Reviewed-by: Alberto Garcia <be...@igalia.com>
Berto
