On 26.10.19 23:25, Alberto Garcia wrote: > Setting the QCOW_OFLAG_ZERO bit of the L2 entry is forbidden if an > image has subclusters. Instead, the individual 'all zeroes' bits must > be used. > > Signed-off-by: Alberto Garcia <[email protected]> > --- > block/qcow2-cluster.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c > index e67559152f..3e4ba8d448 100644 > --- a/block/qcow2-cluster.c > +++ b/block/qcow2-cluster.c > @@ -1852,7 +1852,7 @@ static int zero_in_l2_slice(BlockDriverState *bs, > uint64_t offset, > assert(nb_clusters <= INT_MAX); > > for (i = 0; i < nb_clusters; i++) { > - uint64_t old_offset; > + uint64_t old_offset, l2_entry = 0; > QCow2ClusterType cluster_type; > > old_offset = get_l2_entry(s, l2_slice, l2_index + i); > @@ -1869,12 +1869,18 @@ static int zero_in_l2_slice(BlockDriverState *bs, > uint64_t offset, > > qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice); > if (cluster_type == QCOW2_CLUSTER_COMPRESSED || unmap) { > - set_l2_entry(s, l2_slice, l2_index + i, QCOW_OFLAG_ZERO); > qcow2_free_any_clusters(bs, old_offset, 1, > QCOW2_DISCARD_REQUEST);
It feels wrong to me to free the cluster before updating the L2 entry.
Max
> } else {
> - uint64_t entry = get_l2_entry(s, l2_slice, l2_index + i);
> - set_l2_entry(s, l2_slice, l2_index + i, entry | QCOW_OFLAG_ZERO);
> + l2_entry = get_l2_entry(s, l2_slice, l2_index + i);
> }
> +
> + if (has_subclusters(s)) {
> + set_l2_bitmap(s, l2_slice, l2_index + i,
> QCOW_L2_BITMAP_ALL_ZEROES);
> + } else {
> + l2_entry |= QCOW_OFLAG_ZERO;
> + }
> +
> + set_l2_entry(s, l2_slice, l2_index + i, l2_entry);
> }
>
> qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
>
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