[Samba] truecrypt on synology as subfolder

[Jeremy Allison]

On Fri, Jul 01, 2016 at 12:18:11PM +0200, Xen wrote:
> Jeremy Allison schreef op 30-04-2016 1:06:
> 
> >>Copying a file to my mounted samba share did not work, the files are
> >>created by they remain at 0 size. Then apparently smbd blocks in IO
> >>and never continues, never recovers. I cannot kill the process, I
> >>will have to reboot the NAS but it won't unmount filesystems so I
> >>need a hard reset.
> >
> >That sounds like a kernel bug. Samba only uses normal
> >open/pread/pwrite/
> >close calls which should work on top of truecrypt as far as I know.
> 
> 
> 
> Before I had issues on some device using TrueCrypt because the
> entire thing would hang (mostly SMBD, then) when I read or actually
> wrote files to a truecrypt volume mounted inside of another
> filesystem, so that smbd would have to cross a filesystem boundary.
> 
> I never tested what would happen if the share itself was in the
> mounted crypt, from the beginning.
> 
> I now compiled LUKS on the device and I get an even stranger error
> in a certain sense.
> 
> From the "top level" samba share, the subdirectory that has LUKS
> mounted, doesn't show any files.
> 
> However, when I create another share directly on the mounted LUKS
> subfolder, the files are there.
> 
> So the transition from regular filespace to LUKS filespaces
> (different volume) is not getting this LUKS filespace to appear
> empty to Samba, but not to the linux system itself. Is this to be
> expected?
> 
> Is that normal operation, this?

Hard to tell without logs I'm afraid. We'd need much more data
to tell, but the honest answer is probably "don't do that" :-).