docs: filesystems: convert ceph.txt to ReST

- Add a SPDX header;
- Adjust document title;
- Some whitespace fixes and new line breaks;
- Mark literal blocks as such;
- Add it to filesystems/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/df2f142b5ca5842e030d8209482dfd62dcbe020f.1581955849.git.mchehab+huawei@kernel.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/filesystems/ceph.txt → Documentation/filesystems/ceph.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+============================
 Ceph Distributed File System
 ============================
 
@@ -15,6 +18,7 @@ Basic features include:
  * Easy deployment: most FS components are userspace daemons
 
 Also,
+
  * Flexible snapshots (on any directory)
  * Recursive accounting (nested files, directories, bytes)
 
@@ -63,7 +67,7 @@ no 'du' or similar recursive scan of the file system is required.
 Finally, Ceph also allows quotas to be set on any directory in the system.
 The quota can restrict the number of bytes or the number of files stored
 beneath that point in the directory hierarchy.  Quotas can be set using
-extended attributes 'ceph.quota.max_files' and 'ceph.quota.max_bytes', eg:
+extended attributes 'ceph.quota.max_files' and 'ceph.quota.max_bytes', eg::
 
  setfattr -n ceph.quota.max_bytes -v 100000000 /some/dir
  getfattr -n ceph.quota.max_bytes /some/dir
@@ -76,7 +80,7 @@ from writing as much data as it needs.
 Mount Syntax
 ============
 
-The basic mount syntax is:
+The basic mount syntax is::
 
  # mount -t ceph monip[:port][,monip2[:port]...]:/[subdir] mnt
 
@@ -84,7 +88,7 @@ You only need to specify a single monitor, as the client will get the
 full list when it connects.  (However, if the monitor you specify
 happens to be down, the mount won't succeed.)  The port can be left
 off if the monitor is using the default.  So if the monitor is at
-1.2.3.4,
+1.2.3.4::
 
  # mount -t ceph 1.2.3.4:/ /mnt/ceph
 
@@ -179,8 +183,8 @@ For more information on Ceph, see the home page at
 	https://ceph.com/
 
 The Linux kernel client source tree is available at
-	https://github.com/ceph/ceph-client.git
-	git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client.git
+	- https://github.com/ceph/ceph-client.git
+	- git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client.git
 
 and the source for the full system is at
 	https://github.com/ceph/ceph.git

Documentation/filesystems/index.rst

@@ -55,6 +55,7 @@ Documentation for filesystem implementations.
    befs
    bfs
    btrfs
+   ceph
    fuse
    overlayfs
    virtiofs