Documentation: Update filesystems/gfs2.rst

Remove an obsolete URL and generally bring the doc up-to-date
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Documentation/filesystems/gfs2.rst

 .. SPDX-License-Identifier: GPL-2.0
 
-==================
-Global File System
-==================
+====================
+Global File System 2
+====================
 
-https://fedorahosted.org/cluster/wiki/HomePage
-
-GFS is a cluster file system. It allows a cluster of computers to
+GFS2 is a cluster file system. It allows a cluster of computers to
 simultaneously use a block device that is shared between them (with FC,
-iSCSI, NBD, etc).  GFS reads and writes to the block device like a local
+iSCSI, NBD, etc).  GFS2 reads and writes to the block device like a local
 file system, but also uses a lock module to allow the computers coordinate
 their I/O so file system consistency is maintained.  One of the nifty
-features of GFS is perfect consistency -- changes made to the file system
+features of GFS2 is perfect consistency -- changes made to the file system
 on one machine show up immediately on all other machines in the cluster.
 
-GFS uses interchangeable inter-node locking mechanisms, the currently
+GFS2 uses interchangeable inter-node locking mechanisms, the currently
 supported mechanisms are:
 
   lock_nolock
-    - allows gfs to be used as a local file system
+    - allows GFS2 to be used as a local file system
 
   lock_dlm
-    - uses a distributed lock manager (dlm) for inter-node locking.
+    - uses the distributed lock manager (dlm) for inter-node locking.
       The dlm is found at linux/fs/dlm/
 
-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
+To use GFS2 as a local file system, no external clustering systems are
 needed, simply::
 
   $ mkfs -t gfs2 -p lock_nolock -j 1 /dev/block_device
   $ mount -t gfs2 /dev/block_device /dir
 
-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. For F17 and above
-cman has been replaced by the dlm package.
+The gfs2-utils package is required on all cluster nodes and, for lock_dlm, you
+will also need the dlm and corosync user space utilities configured as per the
+documentation.
+
+gfs2-utils can be found at https://pagure.io/gfs2-utils
 
 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:
+The following man pages are available from gfs2-utils:
 
   ============		=============================================
   fsck.gfs2		to repair a filesystem
   gfs2_grow		to expand a filesystem online
   gfs2_jadd		to add journals to a filesystem online
   tunegfs2		to manipulate, examine and tune a filesystem
-  gfs2_convert		to convert a gfs filesystem to gfs2 in-place
+  gfs2_convert		to convert a gfs filesystem to GFS2 in-place
   mkfs.gfs2		to make a filesystem
   ============		=============================================