Re: [Qemu-devel] [PATCH v7 08/13] qcow2: Fix refcount blocks beyond image end

[Max Reitz]

On 2014-10-22 at 11:24, Kevin Wolf wrote:
> Am 22.10.2014 um 10:08 hat Max Reitz geschrieben:
> > If the qcow2 check function detects a refcount block located beyond the
> > image end, grow the image appropriately. This cannot break anything and
> > is the logical fix for such a case.
> >
> > Signed-off-by: Max Reitz <address@hidden>
> > ---
> >   block/qcow2-refcount.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++----
> >   1 file changed, 59 insertions(+), 4 deletions(-)
> >
> > diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
> > index d484029..3800d3c 100644
> > --- a/block/qcow2-refcount.c
> > +++ b/block/qcow2-refcount.c
> > @@ -1544,7 +1544,8 @@ static int check_refblocks(BlockDriverState *bs, 
> > BdrvCheckResult *res,
> >                              int64_t *nb_clusters)
> >   {
> >       BDRVQcowState *s = bs->opaque;
> > -    int64_t i;
> > +    int64_t i, size;
> > +    int ret;
> >   
> >       for(i = 0; i < s->refcount_table_size; i++) {
> >           uint64_t offset, cluster;
> > @@ -1560,9 +1561,63 @@ static int check_refblocks(BlockDriverState *bs, 
> > BdrvCheckResult *res,
> >           }
> >   
> >           if (cluster >= *nb_clusters) {
> > -            fprintf(stderr, "ERROR refcount block %" PRId64
> > -                    " is outside image\n", i);
> > -            res->corruptions++;
> > +            fprintf(stderr, "%s refcount block %" PRId64 " is outside image\n",
> > +                    fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
> > +
> > +            if (fix & BDRV_FIX_ERRORS) {
> > +                int64_t old_nb_clusters = *nb_clusters;
> > +
> > +                if (offset + s->cluster_size < offset ||
> > +                    offset > INT64_MAX - s->cluster_size)
> Do you still need the first condition with the reworked second one?

Right, we can drop it.

Max

> > +                {
> > +                    ret = -EINVAL;
> > +                    goto resize_fail;
> > +                }
> Kevin