vfs_gpfs(8)

NAME

       vfs_gpfs - gpfs specific samba extensions like acls and prealloc

SYNOPSIS

       vfs objects = gpfs

DESCRIPTION

       This VFS module is part of the samba(7) suite.

       The gpfs VFS module is the home for all gpfs extensions that Samba
       requires for proper integration with GPFS. It uses the GPL library
       interfaces provided by GPFS.

       Currently the gpfs vfs module provides extensions in following areas :

       o   NFSv4 ACL Interfaces with configurable options for GPFS

       o   Kernel oplock support on GPFS

       o   Lease support on GPFS

       NOTE:This module follows the posix-acl behaviour and hence allows
       permission stealing via chown. Samba might allow at a later point in
       time, to restrict the chown via this module as such restrictions are
       the responsibility of the underlying filesystem than of Samba.

       This module is stackable.

OPTIONS

       nfs4:mode = [ simple | special ]
           Enable/Disable substitution of special IDs on GPFS. This parameter
           should not affect the windows users in anyway. It only ensures that
           Samba sets the special IDs - OWNER@ and GROUP@ ( mappings to simple
           uids ) that are relevant to GPFS.

           The following MODEs are understood by the module:

           o   simple(default) - do not use special IDs in GPFS ACEs

           o   special - use special IDs in GPFS ACEs.

       nfs4:acedup = [dontcare|reject|ignore|merge]
           This parameter configures how Samba handles duplicate ACEs
           encountered in GPFS ACLs. GPFS allows/creates duplicate ACE for
           different bits for same ID.

           Following is the behaviour of Samba for different values :

           o   dontcare (default) - copy the ACEs as they come

           o   reject - stop operation and exit with error on ACL set op

           o   ignore - don't include the second matching ACE

           o   merge - bitwise OR the 2 ace.flag fields and 2 ace.mask fields
               of the 2 duplicate ACEs into 1 ACE

       nfs4:chown = [yes|no]
           This parameter allows enabling or disabling the chown supported by
           the underlying filesystem. This parameter should be enabled with
           care as it might leave your system insecure.

           Some filesystems allow chown as a) giving b) stealing. It is the
           latter that is considered a risk.

           Following is the behaviour of Samba for different values :

           o   yes - Enable chown if as supported by the under filesystem

           o   no (default) - Disable chown

EXAMPLES

       A GPFS mount can be exported via Samba as follows :

                   [samba_gpfs_share]
                vfs objects = gpfs
                path = /test/gpfs_mount
                nfs4: mode = special
                nfs4: acedup = merge

CAVEATS

       The gpfs gpl libraries are required by gpfs VFS module during both
       compilation and runtime. Also this VFS module is tested to work on SLES
       9/10 and RHEL 4.4

VERSION

       This man page is correct for version 3.0.25 of the Samba suite.

AUTHOR

       The original Samba software and related utilities were created by
       Andrew Tridgell. Samba is now developed by the Samba Team as an Open
       Source project similar to the way the Linux kernel is developed.

       The GPFS VFS module was created with contributions from Volker Lendecke
       and the developers at IBM.

       This manpage was created by the IBM FSCC team

Samba 3.0                         05/28/2008                       VFS_GPFS(8)