| Message ID | 20170503231120.23507-4-mreitz@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 05/03/2017 06:11 PM, Max Reitz wrote: > In discard_single_l2(), we completely discard normal clusters instead of > simply turning them into preallocated zero clusters. That means we > should probably do the same with such preallocated zero clusters: > Discard them instead of keeping them allocated. > > Reported-by: Eric Blake <eblake@redhat.com> > Signed-off-by: Max Reitz <mreitz@redhat.com> > --- > block/qcow2-cluster.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) Reviewed-by: Eric Blake <eblake@redhat.com> > > diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c > index fb91fd8979..31077d8102 100644 > --- a/block/qcow2-cluster.c > +++ b/block/qcow2-cluster.c > @@ -1511,7 +1511,8 @@ static int discard_single_l2(BlockDriverState *bs, uint64_t offset, > break; > > case QCOW2_CLUSTER_ZERO: > - if (!full_discard) { > + /* Preallocated zero clusters should be discarded in any case */ > + if (!full_discard && (old_l2_entry & L2E_OFFSET_MASK) == 0) { Again, if we had a separate QCOW2_CLUSTER_* for plain vs. pre-allocated zero, this might be easier to write.
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index fb91fd8979..31077d8102 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1511,7 +1511,8 @@ static int discard_single_l2(BlockDriverState *bs, uint64_t offset, break; case QCOW2_CLUSTER_ZERO: - if (!full_discard) { + /* Preallocated zero clusters should be discarded in any case */ + if (!full_discard && (old_l2_entry & L2E_OFFSET_MASK) == 0) { continue; } break;
In discard_single_l2(), we completely discard normal clusters instead of simply turning them into preallocated zero clusters. That means we should probably do the same with such preallocated zero clusters: Discard them instead of keeping them allocated. Reported-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> --- block/qcow2-cluster.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)