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

[Aneesh Kumar K.V]

> 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.

-aneesh