vfs_fileid
8
Samba
System Administration tools
&doc.version;
vfs_fileid
Generates file_id structs with unique device id values for
cluster setups
vfs objects = fileid
DESCRIPTION
This VFS module is part of the
samba
7
suite.
Samba uses file_id structs to uniquely identify files
for locking purpose. By default the file_id contains the device
and inode number returned by the stat() system call.
As the file_id is a unique identifier of a file, it must be the same
on all nodes in a cluster setup. This module overloads the
SMB_VFS_FILE_ID_CREATE() operation and
generates the device number based on the configured algorithm
(see the "fileid:algorithm" option).
When using the fsname or fsid algorithm a
stat() and statfs() call is
required for all mounted file systems to generate the file_id. If e.g.
an NFS file system is unresponsive such a call might block and the smbd
process will become unresponsive. Use the "fileid:fstype deny",
"fileid:fstype allow", "fileid:mntdir deny", or "fileid:mntdir allow"
options to ignore potentially unresponsive file systems.
OPTIONS
fileid:algorithm = ALGORITHM
Available algorithms are fsname,
fsname_nodirs, fsid and
hostname. The default value is
fsname.
The fsname algorithm generates
device id by hashing the kernel device name.
The fsname_nodirs algorithm generates
device id by hashing the kernel device name for files and by hashing
the hostname for directories. This can be used to deliberately
break lock coherency for directories in a cluster.
The fsid algorithm generates
the device id from the f_fsid returned
from the statfs() syscall.
The hostname algorithm generates device
id by hashing the hostname. This can be used to deliberately
break lock coherency in a cluster.
fileid:mapping = ALGORITHM
This option is the legacy version of the
fileid:algorithm option, which was used in earlier
versions of fileid mapping feature in custom Samba 3.0 versions.
fileid:fstype deny = LIST
List of file system types to be ignored for file_id
generation.
fileid:fstype allow = LIST
List of file system types to be allowed for file_id
generation. If this option is set, file system types not listed
here are ignored.
fileid:mntdir deny = LIST
List of file system mount points to be ignored for
file_id generation.
fileid:mntdir allow = LIST
List of file system mount points to be allowed for file_id
generation. If this option is set, file system mount points
not listed here are ignored.
EXAMPLES
Usage of the fileid module with the
fsid algorithm:
fileid
fsid
VERSION
This man page is correct for version &doc.version; 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.