Re: [rdiff-backup-users] rdiff-backup fails on symlink directories

[Maarten Bezemer]

On Mon, 25 Oct 2004, Finn-Arne Johansen wrote:

> There is a line in the log: 
>   File 
> "/var/amd/homelusersa.nvg.ntnu.no/home/amd/lusers/a/werner/work/rdiff-backup/rdiff-backup-0.13.3.jgoerzen/debian/rdiff-backup/usr/lib/python2.2/site-packages/rdiff_backup/connection.py",
>  line 351, in reval
>   OSError: [Errno 13] Permission denied: 
> '/var/lib/slbackup/tjener/skole/tjener/home0/rahal/Desktop/Fellesdokumenter/Arne'
> 
> The backup is run as root, but looking into this on the backup-machine: 
>  ltsp100:~# ls -l 
> /var/lib/slbackup/tjener/skole/tjener/home0/rahal/Desktop/Fellesdokumenter/Arne
>  ls: 
> /var/lib/slbackup/tjener/skole/tjener/home0/rahal/Desktop/Fellesdokumenter/Arne:
>  Permission denied
>  ltsp100:~# ls -l 
> /var/lib/slbackup/tjener/skole/tjener/home0/rahal/Desktop/Fellesdokumenter    
>  
>  lrwxrwxrwx    1 root     root           42 Feb  9  2004 
> /var/lib/slbackup/tjener/skole/tjener/home0/rahal/Desktop/Fellesdokumenter -> 
> /skole/tjener/home0/rahal/Fellesdokumenter
> 
> To me, it looks like rdiff-backup follows the symlink

This seems to be related to the "Serious data loss using rdiff-backup"
thread. Trying to regress the last failed backup, rdiff-backup follows
symlinks in the destination tree and then does weird things if they point
to locations outside the destination tree.
It seems you're quite lucky the NFS tree is exported without
no-root-squash on the server (and as such mapping the 'root' account on
the backup-workstation to a harmless 'nobody' account on the NFS server),
otherwise regressing might very well have destroyed the source directory.

Like others suggested, rdiff-backup should (at least optional) be able to
cope with special files like symlinks and device files properly on the
destination side. E.g. creating device files as a normal user isn't
possible. Backup and restore for those special files shouldn't be too hard
using metadata only.


As I'm still quite new to rdiff-backup and I'm not at all familiar with
the Python language, I try to work around this problem by using the
--exclude-special-files switch and creating a .tgz for all those special
files separately.

Hope this helps..

Regards,
 Maarten Bezemer