[Samba] Pcloud and Rclone: NUL added to beginning of each file

[Jeremy Allison]

On Wed, Nov 21, 2018 at 07:55:36PM +0100, Alessandro Rinaldi via samba wrote:
> Hello,
> I'm experiencing a really strange behaviour with Samba that I can't easily
> debug.
> I have a pCloud account mounted using rCloud (Fuse file system) with the
> following command:
> 
> rclone mount --allow-other --umask 0007 pcloud:/ /media/alerinaldi/pcloud
> 
> The mounted directory is then shared with Samba in read/write.
> 
> It all seemed to work like a charm, except for a really strange behaviour:
> every time I copy a file from a Windows PC to my share, a NUL (0x00)
> character is added to the beginning of it, and the resulting file is then
> corrupted (even if easily repairable).
> 
> It doesn't happen if I copy a file directly inside the server to the
> mounted directory, neither it happens if I copy a file to a share referred
> to a local filesystem.
> 
> I really can't get what is wrong, if it is a matter of Rclone or of Samba
> itself.
> Do some of you have suggestions on where to look at for debugging?

Looks like the rclone mount fuse filesystem has a bug.

100% this isn't a Samba bug, people would have noticed long
ago if we started adding leading zeros to files :-).