fallocate can't change the cifs disk space usage

[Steve French]

One of the things that Samba server appears to be doing wrong is that
Samba is creating the file as a sparse file and returning that it is
not a sparse file - this obviously creates a problem because an
fallocate on a non-sparse file can be a no op ... but the server
didn't tell us it was a sparse file ...

On Mon, Aug 3, 2020 at 10:59 AM Steve French <smfrench at gmail.com> wrote:
>
> So locally on xfs this works, but Samba when receiving the request
> remotely apparently isn't doing the fallocate.  Would be curious if
> this works with vfs_btrfs and btrfs filesystem on the share - or a
> Samba server bug.
>
> On Sun, Aug 2, 2020 at 9:55 PM Xiaoli Feng <xifeng at redhat.com> wrote:
> >
> > Hello all,
> >
> > Recently when I'm investigating the xfstests generic/213 generic/228 failures for cifs.
> > Found that fallocate can't change the cifs disk space usage. Comparing xfs fileystem,
> > fallocate can update space usage.
> >
> > My tests is in 5.8.0-rc7+. I also file a bug for this issue.
> >   https://bugzilla.kernel.org/show_bug.cgi?id=208775
> >
> > # cat /etc/samba/smb.conf
> > [cifs]
> > path=/mnt/cifs
> > writeable=yes
> > # mount //localhost/cifs cifs -o user=root,password=redhat,cache=none,actimeo=0
> > # df -h cifs
> > Filesystem        Size  Used Avail Use% Mounted on
> > //localhost/cifs   36G   23G   13G  66% /root/cifs
> > #  fallocate -o 0 -l 2g /root/cifs/file1
> > # df -h cifs
> > Filesystem        Size  Used Avail Use% Mounted on
> > //localhost/cifs   36G   23G   13G  66% /root/cifs
> > ]# ls -l cifs
> > total 1
> > -rwxr-xr-x. 1 root root 2147483648 Aug  2 21:57 file1
> >
> > Thanks.
> >
> > --
> > Best regards!
> > XiaoLi Feng 冯小丽
> >
>
>
> --
> Thanks,
>
> Steve



-- 
Thanks,

Steve