[Samba] Samba and BTRFS server-side copy

[Saint Germain]

On Thu, 27 Oct 2016 17:30:09 -0700, Jeremy Allison <jra at samba.org>
wrote :

> On Thu, Oct 27, 2016 at 05:22:14PM -0700, Jeremy Allison via samba
> wrote:
> > 
> > Looking around inside that source code I also see:
> > 
> > do_read (GVfsBackend *backend,
> >          GVfsJobRead *job,
> >          GVfsBackendHandle handle,
> >          char *buffer,
> >          gsize bytes_requested)
> > {
> >   GVfsBackendSmb *op_backend = G_VFS_BACKEND_SMB (backend);
> >   ssize_t res;
> >   smbc_read_fn smbc_read;
> > 
> >   /* libsmbclient limits blocksize to (64*1024)-2 for Windows
> > servers,
> >    * let's do the same here to achieve reasonable performance.
> > (#588391) *
> >    * TODO: port to pull mechanism (#592468)
> >    */
> >   if (bytes_requested > 65534)
> >     bytes_requested = 65534;
> > 
> >   smbc_read = smbc_getFunctionRead (op_backend->smb_context);
> >   res = smbc_read (op_backend->smb_context, (SMBCFILE *)handle,
> > buffer, bytes_requested);
> > 
> > which is also completely broken and wrong. The read call
> > can take any arbitrary size and the both the libsmbclient
> > SMB1 and SMB2 engines will break this down into as many
> > simultaneous on the wire calls as needed to pipeline
> > the reads / writes.
> > 
> > Restricting this to 65534 is *insane* and slow. That
> > whole chunk of code restricting the size needs to be
> > removed.
> 
> Oh it's my fault from 2009:
> 
> https://bugzilla.gnome.org/show_bug.cgi?id=588391#c10
> 
> :-).
> 
> I'll log another bug to get the whole thing removed
> now we pipeline correctly.

I just tried and when I limit samba to SMB2 connections (in smb.conf),
Nautilus/gvfs cannot connect (it doesn't even see the share).

I also tried starting a discussion on the topic yesterday:
https://mail.gnome.org/archives/gvfs-list/2016-October/msg00000.html

It seems that Ross Lagerwall started working on the topic a while ago,
but I don't know when/how the code will be included.

Thanks for your help !