Re: [Samba] Fw: Btrfs Samba and Quotas

[Jeremy Allison <jra@samba.org>]

On Mon, May 20, 2019 at 05:54:13PM +0000, Hendrik Friedel via samba wrote:
> Hello,
> 
> > Is btrfs becoming more common ?
> In my impression: Yes. Also, this problem seems to affect also zfs and thus
> all (?) file systems that support checksums and scrubbing in linux;
> consequently all filesystems that are the choice of users who need this for
> ensuring data consistency.
> > You posted this:
> > 
> > I am using Openmediavault (debian based NAS distribution), which is not actively supporting btrfs
> > 
> > It is this that I was referring to.
> Ah, yes.
> OMV intended to move to btrfs as the only choice with the next version. In
> order to pave the way, I intended to be an early adopter. The problem I
> report here, that there is good reason to.
> 
> > > > it just a pain in the a.. Never use it together with quotas or CTDB it
> > > > will crash after short time. I only take xfs and have no problem at all.
> > > > I don't know wy, but it's not good idea to user brtfs with samba.
> > > 
> > > Well, as long as this is not being reported and being improved, it will remain that way...
> > > 
> > Possibly, but it works great with ext4
> Glad to hear that.
> > I suggest you sit down with a copy of 'man smb.conf' and remove all the default
> My intent is not to solve *my* problem, but to make developers aware of this
> issue and help getting this issue fixed.
> 
> I feel a bit helpless though, as I perceive a lack of interest...
> I mean... This Bug is now celebrating its 5th aniversary.
> https://bugzilla.samba.org/show_bug.cgi?id=10541

That's because the concept of a btrfs "subvolume" completely
breaks the POSIX idioms that smbd depends on.

We absolutely identify a file by a dev/ino pair, and
expect the dev to remain consistent under an exported
share path.

If you sub-mount this also breaks smbd dfree/quotas, and
that's a lot more common.

This identity is baked into Samba in order to implement
leases/oplocks and it's not going to change.

If you want to do this (subvolumes/submounts) I think
you should get familiar with the:

dfree command:

set quota command:

set quota command:

scripts in smb.conf.