Chapter 19. Stackable VFS modules

19.1. Introduction and configuration

Since samba 3.0, samba supports stackable VFS(Virtual File System) modules. Samba passes each request to access the unix file system thru the loaded VFS modules. This chapter covers all the modules that come with the samba source and references to some external modules.

You may have problems to compile these modules, as shared libraries are compiled and linked in different ways on different systems. I currently tested them against GNU/linux and IRIX.

To use the VFS modules, create a share similar to the one below. The important parameter is the vfs object parameter which must point to the exact pathname of the shared library object. For example, to use audit.so:

       [audit]
                comment = Audited /data directory
                path = /data
                vfs object = /path/to/audit.so
                writeable = yes
                browseable = yes

Further documentation on writing VFS modules for Samba can be found in docs directory of the Samba source distribution.

19.2. Included modules

19.2.1. audit

A simple module to audit file access to the syslog facility. The following operations are logged:

share
connect/disconnect
directory opens/create/remove
file open/close/rename/unlink/chmod

19.2.2. recycle

A recycle-bin like modules. When used any unlink call will be intercepted and files moved to the recycle directory instead of beeing deleted.

Supported options:

vfs_recycle_bin:repository

FIXME

vfs_recycle_bin:keeptree

FIXME

vfs_recycle_bin:versions

FIXME

vfs_recycle_bin:touch

FIXME

vfs_recycle_bin:maxsize

FIXME

vfs_recycle_bin:exclude

FIXME

vfs_recycle_bin:exclude_dir

FIXME

vfs_recycle_bin:noversions

FIXME

19.2.3. netatalk

A netatalk module, that will ease co-existence of samba and netatalk file sharing services.

Advantages compared to the old netatalk module:

it doesn't care about creating of .AppleDouble forks, just keeps ones in sync
if share in smb.conf doesn't contain .AppleDouble item in hide or veto list, it will be added automatically

19.3. VFS modules available elsewhere

This section contains a listing of various other VFS modules that have been posted but don't currently reside in the Samba CVS tree for one reason ot another (e.g. it is easy for the maintainer to have his or her own CVS tree).

No statemets about the stability or functionality any module should be implied due to its presence here.

19.3.1. DatabaseFS

URL: http://www.css.tayloru.edu/~elorimer/databasefs/index.php

By Eric Lorimer.

I have created a VFS module which implements a fairly complete read-only filesystem. It presents information from a database as a filesystem in a modular and generic way to allow different databases to be used (originally designed for organizing MP3s under directories such as "Artists," "Song Keywords," etc... I have since applied it to a student roster database very easily). The directory structure is stored in the database itself and the module makes no assumptions about the database structure beyond the table it requires to run.

Any feedback would be appreciated: comments, suggestions, patches, etc... If nothing else, hopefully it might prove useful for someone else who wishes to create a virtual filesystem.

19.3.2. vscan

URL: http://www.openantivirus.org/

samba-vscan is a proof-of-concept module for Samba, which uses the VFS (virtual file system) features of Samba 2.2.x/3.0 alphaX. Of couse, Samba has to be compiled with VFS support. samba-vscan supports various virus scanners and is maintained by Rainer Link.