Re: [Qemu-devel] [PATCH v2 3/5] qcow2: Employ metadata overlap checks

[Max Reitz]

Am 29.08.2013 11:18, schrieb Kevin Wolf:
> Am 28.08.2013 um 16:55 hat Max Reitz geschrieben:
> > The pre-write overlap check function is now called before most of the
> > qcow2 writes (aborting it on collision or other error).
> >
> > Signed-off-by: Max Reitz <address@hidden>
> > ---
> >   block/qcow2-cache.c    | 17 +++++++++++++++++
> >   block/qcow2-cluster.c  | 21 +++++++++++++++++++++
> >   block/qcow2-snapshot.c | 22 ++++++++++++++++++++++
> >   block/qcow2.c          | 36 +++++++++++++++++++++++++++++++++++-
> >   4 files changed, 95 insertions(+), 1 deletion(-)
> > @@ -1753,10 +1779,18 @@ static int qcow2_save_vmstate(BlockDriverState *bs, 
> > QEMUIOVector *qiov,
> >       BDRVQcowState *s = bs->opaque;
> >       int growable = bs->growable;
> >       int ret;
> > +    int64_t offset = qcow2_vm_state_offset(s) + pos;
> >   
> >       BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
> >       bs->growable = 1;
> > -    ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov);
> > +
> > +    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset,
> > +                                        qiov->size);
> > +    if (ret < 0) {
> > +        return ret;
> > +    }
> > +
> > +    ret = bdrv_pwritev(bs, offset, qiov);
> >       bs->growable = growable;
> >   
> >       return ret;
> Sorry for not catching it in v1, this one is actually wrong. The
> bdrv_pwritev() is against bs, not bs->file, so you would be comparing
> virtual/guest offsets with physical/host offsets.
Oh, yes, sorry; thanks for noticing. I do this mistake way too often – I 
think it's time for some regex to catch it…

Max