10.10.2018 19:39, Vladimir Sementsov-Ogievskiy wrote:
> 17.08.2018 15:22, Vladimir Sementsov-Ogievskiy wrote:
>> Rewrite corrupted L2 table entry, which reference space out of
>> underlying file.
>>
>> Make this L2 table entry read-as-all-zeros without any allocation.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
>> ---
>> block/qcow2-refcount.c | 32 ++++++++++++++++++++++++++++++++
>> 1 file changed, 32 insertions(+)
>>
>> diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
>> index 3c004e5bfe..3de3768a3c 100644
>> --- a/block/qcow2-refcount.c
>> +++ b/block/qcow2-refcount.c
>> @@ -1720,8 +1720,30 @@ static int check_refcounts_l2(BlockDriverState
>> *bs, BdrvCheckResult *res,
>> /* Mark cluster as used */
>> csize = (((l2_entry >> s->csize_shift) & s->csize_mask)
>> + 1) *
>> BDRV_SECTOR_SIZE;
>> + if (csize > s->cluster_size) {
>> + ret = fix_l2_entry_to_zero(
>> + bs, res, fix, l2_offset, i, active,
>> + "compressed cluster larger than cluster:
>> size 0x%"
>> + PRIx64, csize);
>> + if (ret < 0) {
>> + goto fail;
>> + }
>> + continue;
>> + }
>> +
>> coffset = l2_entry & s->cluster_offset_mask &
>> ~(BDRV_SECTOR_SIZE - 1);
>> + if (coffset >= bdrv_getlength(bs->file->bs)) {
>> + ret = fix_l2_entry_to_zero(
>> + bs, res, fix, l2_offset, i, active,
>> + "compressed cluster out of file: offset 0x%"
>> PRIx64,
>> + coffset);
>> + if (ret < 0) {
>> + goto fail;
>> + }
>> + continue;
>> + }
>> +
>> ret = qcow2_inc_refcounts_imrt(bs, res,
>> refcount_table,
>> refcount_table_size,
>> coffset, csize);
>> @@ -1748,6 +1770,16 @@ static int check_refcounts_l2(BlockDriverState
>> *bs, BdrvCheckResult *res,
>> {
>> uint64_t offset = l2_entry & L2E_OFFSET_MASK;
>> + if (offset >= bdrv_getlength(bs->file->bs)) {
>> + ret = fix_l2_entry_to_zero(
>> + bs, res, fix, l2_offset, i, active,
>> + "cluster out of file: offset 0x%" PRIx64,
>> offset);
>> + if (ret < 0) {
>> + goto fail;
>> + }
>> + continue;
>> + }
>> +
>> if (flags & CHECK_FRAG_INFO) {
>> res->bfi.allocated_clusters++;
>> if (next_contiguous_offset &&
>
> hmm, interesting question here: in case of misaligned l2 entry, we
> zero it out only for QCOW2_CLUSTER_ZERO_ALLOC, but not for normal
> clusters? Why? I think it is ok to mark as zero misaligned normal
> cluster l2 entry, otherwise we'll have fatal corruption on any
> operation to this cluster.
>
or we can just align them down.
--
Best regards,
Vladimir
