Re: [Qemu-devel] [PATCH v5 01/11] qcow2: Calculate refcount block entry count

[Max Reitz]

On 20.10.2014 at 16:25, Kevin Wolf wrote:
> Am 29.08.2014 um 23:40 hat Max Reitz geschrieben:
> > The size of a refblock entry is (in theory) variable; calculate
> > therefore the number of entries per refblock and the according bit shift
> > (1 << x == entry count) when opening an image.
> >
> > Signed-off-by: Max Reitz <address@hidden>
> > ---
> >   block/qcow2.c | 2 ++
> >   block/qcow2.h | 2 ++
> >   2 files changed, 4 insertions(+)
> >
> > diff --git a/block/qcow2.c b/block/qcow2.c
> > index f9e045f..172ad00 100644
> > --- a/block/qcow2.c
> > +++ b/block/qcow2.c
> > @@ -689,6 +689,8 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, 
> > int flags,
> >   
> >       s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
> >       s->l2_size = 1 << s->l2_bits;
> > +    s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3);
> > +    s->refcount_block_size = 1 << s->refcount_block_bits;
> >       bs->total_sectors = header.size / 512;
> >       s->csize_shift = (62 - (s->cluster_bits - 8));
> >       s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
> > diff --git a/block/qcow2.h b/block/qcow2.h
> > index 6aeb7ea..7c01fb7 100644
> > --- a/block/qcow2.h
> > +++ b/block/qcow2.h
> > @@ -222,6 +222,8 @@ typedef struct BDRVQcowState {
> >       int l2_size;
> >       int l1_size;
> >       int l1_vm_state_index;
> > +    int refcount_block_bits;
> > +    int refcount_block_size;
> Might just be me, but size sounds to me as if the unit were bytes. Would
> you mind renaming this as refcount_block_entries or refblock_entries?

If I'm doing a v7, no. Otherwise, well, see l1_size and l2_size. ;-)

Max