Date: Tue, 14 Nov 2023 22:13:48 +0200 From: Konstantin Belousov <kib@freebsd.org> To: Mateusz Guzik <mjguzik@gmail.com> Cc: Alexander Motin <mav@freebsd.org>, Ronald Klop <ronald-lists@klop.ws>, current@freebsd.org Subject: Re: crash zfs_clone_range() Message-ID: <ZVPU_NidgNThe8j-@kib.kiev.ua> In-Reply-To: <CAGudoHHOvOD6YSE_GxU=kK_euDjRmVo4t2XicAMRd6-sstWEOw@mail.gmail.com> References: <349700057.3452.1699611152405@localhost> <c9c8ab33-efce-5ed0-1f3f-311fa3cf1338@FreeBSD.org> <ZVEdyHFJyTg0cqCo@kib.kiev.ua> <1900239445.5968.1699966796547@localhost> <CAGudoHGdhaea9mkF3RZSCgXuEGNesb9AtkLXrYQNncgreYsv=g@mail.gmail.com> <ea3b2421-a07c-e7c2-68eb-908185dbb98f@FreeBSD.org> <ca2b13ee-7144-96ce-78a2-118c7982de23@FreeBSD.org> <CAGudoHHOvOD6YSE_GxU=kK_euDjRmVo4t2XicAMRd6-sstWEOw@mail.gmail.com>
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On Tue, Nov 14, 2023 at 07:51:39PM +0100, Mateusz Guzik wrote:
> On 11/14/23, Alexander Motin <mav@freebsd.org> wrote:
> > On 14.11.2023 12:44, Alexander Motin wrote:
> >> On 14.11.2023 12:39, Mateusz Guzik wrote:
> >>> One of the vnodes is probably not zfs, I suspect this will do it
> >>> (untested):
> >>>
> >>> diff --git a/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c
> >>> b/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c
> >>> index 107cd69c756c..e799a7091b8e 100644
> >>> --- a/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c
> >>> +++ b/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c
> >>> @@ -6270,6 +6270,11 @@ zfs_freebsd_copy_file_range(struct
> >>> vop_copy_file_range_args *ap)
> >>> goto bad_write_fallback;
> >>> }
> >>> }
> >>> +
> >>> + if (invp->v_mount->mnt_vfc != outvp->v_mount->mnt_vfc) {
> >>> + goto bad_write_fallback;
> >>> + }
> >>> +
> >>> if (invp == outvp) {
> >>> if (vn_lock(outvp, LK_EXCLUSIVE) != 0) {
> >>> goto bad_write_fallback;
> >>>
> >>
> >> vn_copy_file_range() verifies for that:
> >>
> >> /*
> >> * If the two vnodes are for the same file system type, call
> >> * VOP_COPY_FILE_RANGE(), otherwise call
> >> vn_generic_copy_file_range()
> >> * which can handle copies across multiple file system types.
> >> */
> >> *lenp = len;
> >> if (inmp == outmp || strcmp(inmp->mnt_vfc->vfc_name,
> >> outmp->mnt_vfc->vfc_name) == 0)
> >> error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp,
> >> outoffp,
> >> lenp, flags, incred, outcred, fsize_td);
> >> else
> >> error = vn_generic_copy_file_range(invp, inoffp, outvp,
> >> outoffp, lenp, flags, incred, outcred, fsize_td);
> >
> > Thinking again, what happen if there are two nullfs mounts on top of two
> > different file systems, one of which is indeed not ZFS? Do we need to
> > add those checks to all ZFS, NFS and FUSE, implementing
> > VOP_COPY_FILE_RANGE, or it is responsibility of nullfs or VFS?
> >
>
> I already advocated for not trying to guess for filesystems what they
> can or cannot handle internally.
>
> That is to say vn_copy_file_range should call VOP_COPY_FILE_RANGE,
> that can try to figure out what to do and if it got nothing punt to a
> fallback. This already happens for some of the cases.
>
It is nullfs that is to blame there.
See https://reviews.freebsd.org/D42603
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