Provided by: samba-vfs-modules_4.3.11+dfsg-0ubuntu0.16.04.34_amd64 
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 :
• NFSv4 ACL Interfaces with configurable options for GPFS
• Kernel oplock support on GPFS
• 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 makes use of the smb.conf parameter acl map full control. When set to yes (the
default), this parameter will add in the FILE_DELETE_CHILD bit on a returned ACE entry for
a file (not a directory) that already contains all file permissions except for FILE_DELETE
and FILE_DELETE_CHILD. This can prevent Windows applications that request GENERIC_ALL
access from getting ACCESS_DENIED errors when running against a filesystem with NFSv4
compatible ACLs.
This module is stackable.
Since Samba 4.0 all options are per share options.
OPTIONS
gpfs:sharemodes = [ yes | no ]
Enable/Disable cross node sharemode handling for GPFS.
• yes(default) - propagate sharemodes across all GPFS nodes.
• no - do not propagate sharemodes across all GPFS nodes. This should only be used
if the GPFS file system is exclusively exported by Samba. Access by local unix
application or NFS exports could lead to corrupted files.
gpfs:leases = [ yes | no ]
Enable/Disable cross node leases (oplocks) for GPFS. You should also set the oplocks
and kernel oplocks options to the same value.
• yes(default) - propagate leases across all GPFS nodes.
• no - do not propagate leases across all GPFS nodes. This should only be used if
the GPFS file system is exclusively exported by Samba. Access by local unix
application or NFS exports could lead to corrupted files.
gpfs:hsm = [ yes | no ]
Enable/Disable announcing if this FS has HSM enabled.
• no(default) - Do not announce HSM.
• yes - Announce HSM.
gpfs:recalls = [ yes | no ]
When this option is set to no, an attempt to open an offline file will be rejected
with access denied. This helps preventing recall storms triggered by careless
applications like Finder and Explorer.
• yes(default) - Open files that are offline. This will recall the files from HSM.
• no - Reject access to offline files with access denied. This will prevent recalls
of files from HSM. Using this setting also requires gpfs:hsm to be set to yes.
gpfs:getrealfilename = [ yes | no ]
Enable/Disable usage of the gpfs_get_realfilename_path() function. This improves the
casesensitive wildcard file name access.
• yes(default) - use gpfs_get_realfilename_path().
• no - do not use gpfs_get_realfilename_path(). It seems that
gpfs_get_realfilename_path() doesn't work on AIX.
gpfs:winattr = [ yes | no ]
Enable/Disable usage of the windows attributes in GPFS. GPFS is able to store windows
file attributes e.g. HIDDEN, READONLY, SYSTEM and others natively. That means Samba
doesn't need to map them to permission bits or extended attributes.
• no(default) - do not use GPFS windows attributes.
• yes - use GPFS windows attributes.
gpfs:merge_writeappend = [ yes | no ]
GPFS ACLs doesn't know about the 'APPEND' right. This option lets Samba map the
'APPEND' right to 'WRITE'.
• yes(default) - map 'APPEND' to 'WRITE'.
• no - do not map 'APPEND' to 'WRITE'.
gpfs:acl = [ yes | no ]
This option lets Samba use or ignore GPFS ACLs.
• yes(default) - use GPFS ACLs.
• no - do not use GPFS ACLs and pass everything to the next SMB_VFS module.
gpfs:refuse_dacl_protected = [ yes | no ]
As GPFS does not support the ACE4_FLAG_NO_PROPAGATE NFSv4 flag (which would be the
mapping for the DESC_DACL_PROTECTED flag), the status of this flag is currently
silently ignored by Samba. That means that if you deselect the "Allow inheritable
permissions..." checkbox in Windows' ACL dialog and then apply the ACL, the flag will
be back immediately.
To make sure that automatic migration with e.g. robocopy does not lead to ACLs
silently (and unintentionally) changed, you can set gpfs:refuse_dacl_protected = yes
to enable an explicit check for this flag and if set, it will return
NT_STATUS_NOT_SUPPORTED so errors are shown up on the Windows side and the
Administrator is aware of the ACLs not being settable like intended
• no(default) - ignore the DESC_DACL_PROTECTED flags.
• yes - reject ACLs with DESC_DACL_PROTECTED.
gpfs:dfreequota = [ yes | no ]
Adjust reporting of the size and free space of a share according to quotas. If this
setting is "yes", a request for size and free space will also evaluate the user quota
of the user requesting the data and the group quota of the primary group of the user.
Fileset quotas are not queried, since GPFS already provides the option --dfreequota to
reflect the fileset quota in the free space query. Please use that option to include
fileset quotas in the reported disk space.
If any of the soft or hard quota limits has been reached, the free space will be
reported as 0. If a quota is in place, but the limits have not been reached, the free
space will be reported according to the space left in the quota. If more than one
quota applies the free space will be reported as the smallest space left in those
quotas. The size of the share will be reported according to the quota usage. If more
than one quota applies, the smallest size will be reported for the share size
according to these quotas.
• yes - include the quotas when reporting the share size and free space
• no(default) - do not include quotas, simply report the size and free space of the
file system
gpfs:prealloc = [ yes | no ]
If set to yes the gpfs_prealloc function will be used in the fallocate callback when
appropriate. If set to no gpfs_prealloc will not be used. In both cases the system and
libc calls are avoided.
• yes (default) - Use gpfs_prealloc for the fallocate callback.
• no - Do not use gpfs_prealloc for the fallocate callback.
gpfs:settimes = [ yes | no ]
Use the gpfs_set_times API when changing the timestamps of a file or directory. If the
GPFS API is not available the old method of using utime and the GPFS winattr call will
be used instead.
• yes(default) - Use gpfs_set_times. Fall back to utime and winattr when it is not
available.
• no - Do not use gpfs_set_times.
nfs4:mode = [ simple | special ]
Controls substitution of special IDs (OWNER@ and GROUP@) on GPFS. The use of mode
simple is recommended. In this mode only non inheriting ACL entries for the file owner
and group are mapped to special IDs.
The following MODEs are understood by the module:
• simple(default) - use OWNER@ and GROUP@ special IDs for non inheriting ACEs only.
• special(deprecated) - use OWNER@ and GROUP@ special IDs in ACEs for all file owner
and group 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 :
• dontcare (default) - copy the ACEs as they come
• reject - stop operation and exit with error on ACL set op
• ignore - don't include the second matching ACE
• 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 :
• yes - Enable chown if as supported by the under filesystem
• no (default) - Disable chown
gpfs:syncio = [yes|no]
This parameter makes Samba open all files with O_SYNC. This triggers optimizations in
GPFS for workloads that heavily share files.
Following is the behaviour of Samba for different values:
• yes - Open files with O_SYNC
• no (default) - Open files as normal Samba would do
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
Depending on the version of gpfs, the libgpfs_gpl library or the libgpfs library is needed
at runtime by the gpfs VFS module: Starting with gpfs 3.2.1 PTF8, the complete libgpfs is
available as open source and libgpfs_gpl does no longer exist. With earlier versions of
gpfs, only the libgpfs_gpl library was open source and could be used at run time.
At build time, only the header file gpfs_gpl.h is required, which is a symlink to gpfs.h
in gpfs versions newer than 3.2.1 PTF8.
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