GFS2: Update docs

go_unlock        | Called on the final local unlock of a lock

go_dump          | Called to print content of object for debugfs file, or on

                 | error to dump glock to the log.

go_type;         | The type of the glock, LM_TYPE_.....

go_type          | The type of the glock, LM_TYPE_.....

go_min_hold_time | The minimum hold time

The minimum hold time for each lock is the time after a remote lock

features of GFS is perfect consistency -- changes made to the file system

on one machine show up immediately on all other machines in the cluster.

GFS uses interchangable inter-node locking mechanisms.  Different lock

modules can plug into GFS and each file system selects the appropriate

lock module at mount time.  Lock modules include:

GFS uses interchangable inter-node locking mechanisms, the currently

supported mechanisms are:

  lock_nolock -- allows gfs to be used as a local file system

  lock_dlm -- uses a distributed lock manager (dlm) for inter-node locking

  The dlm is found at linux/fs/dlm/

In addition to interfacing with an external locking manager, a gfs lock

module is responsible for interacting with external cluster management

systems.  Lock_dlm depends on user space cluster management systems found

Lock_dlm depends on user space cluster management systems found

at the URL above.

To use gfs as a local file system, no external clustering systems are

  $ mkfs -t gfs2 -p lock_nolock -j 1 /dev/block_device

  $ mount -t gfs2 /dev/block_device /dir

GFS2 is not on-disk compatible with previous versions of GFS.

If you are using Fedora, you need to install the gfs2-utils package

and, for lock_dlm, you will also need to install the cman package

and write a cluster.conf as per the documentation.

GFS2 is not on-disk compatible with previous versions of GFS, but it

is pretty close.

The following man pages can be found at the URL above:

  gfs2_fsck	to repair a filesystem

  fsck.gfs2	to repair a filesystem

  gfs2_grow	to expand a filesystem online

  gfs2_jadd	to add journals to a filesystem online

  gfs2_tool	to manipulate, examine and tune a filesystem

  gfs2_quota	to examine and change quota values in a filesystem

  gfs2_convert	to convert a gfs filesystem to gfs2 in-place

  mount.gfs2	to help mount(8) mount a filesystem

  mkfs.gfs2	to make a filesystem