Re: [Qemu-devel] [PATCH] add CephFS support in VirtFS

[Jevon Qiao]

On 14/2/16 14:01, Aneesh Kumar K.V wrote:
> > diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
> > index f972731..385c01d 100644
> > --- a/hw/9pfs/virtio-9p.c
> > +++ b/hw/9pfs/virtio-9p.c
> > @@ -1326,7 +1326,7 @@ out_nofid:
> >    static int32_t get_iounit(V9fsPDU *pdu, V9fsPath *path)
> >    {
> >        struct statfs stbuf;
> > -    int32_t iounit = 0;
> > +    int32_t iounit = 0, unit = 0;
> >        V9fsState *s = pdu->s;
> >
> >        /*
> > @@ -1334,8 +1334,21 @@ static int32_t get_iounit(V9fsPDU *pdu, V9fsPath
> > *path)
> >         * and as well as less than (client msize - P9_IOHDRSZ))
> >         */
> >        if (!v9fs_co_statfs(pdu, path, &stbuf)) {
> > -        iounit = stbuf.f_bsize;
> > -        iounit *= (s->msize - P9_IOHDRSZ)/stbuf.f_bsize;
> > +    /*
> > +     * If host filesystem block size is larger than client msize,
> > +     * we will use AGESIZE as the unit. The reason why we choose
> > +     * AGESIZE is because the data will be splitted in terms of
> > +     * AGESIZE in the virtio layer. In this case, the final
> > +     * iounit is equal to the value of ((msize/unit) - 1) * unit.
> > +     */
> > +    if (stbuf.f_bsize > s->msize) {
> > +        iounit = 4096;
> > +        unit = 4096;
> > +    } else {
> > +            iounit = stbuf.f_bsize;
> > +        unit = stbuf.f_bsize;
> > +    }
> > +        iounit *= (s->msize - P9_IOHDRSZ)/unit;
> >        }
> >        if (!iounit) {
> >            iounit = s->msize - P9_IOHDRSZ;
> > --
>
> Can you split this out as a separate patch ?. Also explain what is
> AGESIZE.
Sure thing. "AGESIZE" is supposed to be "PAGESIZE".

Thanks,
Jevon
> -aneesh