Re: [PATCH] GOP_ALLOC and fallocate for PUFFS

["J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>]

On 02 Oct 2014, at 06:45, Emmanuel Dreyfus <manu%netbsd.org@localhost> wrote:

> J. Hannken-Illjes <hannken%eis.cs.tu-bs.de@localhost> wrote:
> 
>> genfs_gop_write calls genfs_do_io which does "error = biowait(mbp);"
>> near the end.  This will catch errors from VOP_STRATEGY.
> 
> I run the code below but VOP_PUTPAGES never return anything else than 0.

Sure -- why should it?

GOP_ALLOC() gets called from VOP_GETPAGES() for missing pages.  Here you
run VOP_PUTPAGES() on a range known to be unmapped so it becomes a NOP.

GOP_ALLOC() aka puffs_gop_alloc() has to run on the client to make
sure the pages in question are allocated and may be faulted in.

The client has to fill holes or extend files.

> int
> puffs_gop_alloc(struct vnode *vp, off_t off, off_t len,
>                int flags, kauth_cred_t cred)
> {
>        struct puffs_mount *pmp = MPTOPUFFSMP(vp->v_mount);
>        off_t start, end;
>        int pgo_flags = PGO_CLEANIT|PGO_SYNCIO|PGO_PASTEOF;
>        int u_flags = PUFFS_UPDATESIZE|PUFFS_UPDATEMTIME|PUFFS_UPDATECTIME;
>        int error;
> 
>        if (EXISTSOP(pmp, FALLOCATE)) {
>                error = _puffs_vnop_fallocate(vp, off, len);
>                goto out;
>        }
> 
>        start = trunc_page(off);
>        end = round_page(off + len);
> 
>        if (off + len > vp->v_size)
>                uvm_vnp_setwritesize(vp, off + len);
> 
>        mutex_enter(vp->v_interlock);
>        error = VOP_PUTPAGES(vp, start, end, pgo_flags);
> 
>        if (off + len > vp->v_size) {
>                if (error == 0) {
>                        uvm_vnp_setsize(vp, off + len);
>                        puffs_updatenode(VPTOPP(vp), u_flags, vp->v_size);
>                } else {
>                        uvm_vnp_setwritesize(vp, vp->v_size);
>                }
>        }
> out:
>        return error;
> }

--
J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig (Germany)