docs: filesystems: convert gfs2-uevents.txt to ReST

This document is almost in ReST format: all it needs is to have
the titles adjusted and add a SPDX header. In other words:

- Add a SPDX header;
- Add a document title;
- Adjust section titles;
- Add it to filesystems/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Bob Peterson <rpeterso@redhat.com>
Link: https://lore.kernel.org/r/1d1c46b7e86bd0a18d9abbea0de0bc2be84e5e2b.1581955849.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/filesystems/gfs2-uevents.rst

@@ -1,14 +1,18 @@
-                              uevents and GFS2
+.. SPDX-License-Identifier: GPL-2.0
-                             ==================
+
+================
+uevents and GFS2
+================
 
 During the lifetime of a GFS2 mount, a number of uevents are generated.
 This document explains what the events are and what they are used
 for (by gfs_controld in gfs2-utils).
 
 A list of GFS2 uevents
------------------------
+======================
 
 1. ADD
+------
 
 The ADD event occurs at mount time. It will always be the first
 uevent generated by the newly created filesystem. If the mount
@@ -21,6 +25,7 @@ with no journal assigned), and read-only (with journal assigned) status
 of the filesystem respectively.
 
 2. ONLINE
+---------
 
 The ONLINE uevent is generated after a successful mount or remount. It
 has the same environment variables as the ADD uevent. The ONLINE
@@ -29,6 +34,7 @@ RDONLY are a relatively recent addition (2.6.32-rc+) and will not
 be generated by older kernels.
 
 3. CHANGE
+---------
 
 The CHANGE uevent is used in two places. One is when reporting the
 successful mount of the filesystem by the first node (FIRSTMOUNT=Done).
@@ -52,6 +58,7 @@ cluster. For this reason the ONLINE uevent was used when adding a new
 uevent for a successful mount or remount.
 
 4. OFFLINE
+----------
 
 The OFFLINE uevent is only generated due to filesystem errors and is used
 as part of the "withdraw" mechanism. Currently this doesn't give any
@@ -59,6 +66,7 @@ information about what the error is, which is something that needs to
 be fixed.
 
 5. REMOVE
+---------
 
 The REMOVE uevent is generated at the end of an unsuccessful mount
 or at the end of a umount of the filesystem. All REMOVE uevents will
@@ -68,9 +76,10 @@ kobject subsystem.
 
 
 Information common to all GFS2 uevents (uevent environment variables)
-----------------------------------------------------------------------
+=====================================================================
 
 1. LOCKTABLE=
+--------------
 
 The LOCKTABLE is a string, as supplied on the mount command
 line (locktable=) or via fstab. It is used as a filesystem label
@@ -78,6 +87,7 @@ as well as providing the information for a lock_dlm mount to be
 able to join the cluster.
 
 2. LOCKPROTO=
+-------------
 
 The LOCKPROTO is a string, and its value depends on what is set
 on the mount command line, or via fstab. It will be either
@@ -85,12 +95,14 @@ lock_nolock or lock_dlm. In the future other lock managers
 may be supported.
 
 3. JOURNALID=
+-------------
 
 If a journal is in use by the filesystem (journals are not
 assigned for spectator mounts) then this will give the
 numeric journal id in all GFS2 uevents.
 
 4. UUID=
+--------
 
 With recent versions of gfs2-utils, mkfs.gfs2 writes a UUID
 into the filesystem superblock. If it exists, this will

Documentation/filesystems/index.rst

@@ -66,6 +66,7 @@ Documentation for filesystem implementations.
    ext3
    f2fs
    gfs2
+   gfs2-uevents
    fuse
    overlayfs
    virtiofs