docs: filesystems: convert ecryptfs.txt to ReST

- Add a SPDX header;
- Add a document title;
- use :field: markup;
- Some whitespace fixes and new line breaks;
- Mark literal blocks as such;
- Add table markups;
- Add it to filesystems/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Tyler Hicks <code@tyhicks.com>
Link: https://lore.kernel.org/r/6e13841ebd00c8d988027115c75c58821bb41a0c.1581955849.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/filesystems/ecryptfs.rst

@@ -1,14 +1,18 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================================================
 eCryptfs: A stacked cryptographic filesystem for Linux
+======================================================
 
 eCryptfs is free software. Please see the file COPYING for details.
 For documentation, please see the files in the doc/ subdirectory.  For
 building and installation instructions please see the INSTALL file.
 
-Maintainer: Phillip Hellewell
-Lead developer: Michael A. Halcrow <mhalcrow@us.ibm.com>
-Developers: Michael C. Thompson
-            Kent Yoder
-Web Site: http://ecryptfs.sf.net
+:Maintainer: Phillip Hellewell
+:Lead developer: Michael A. Halcrow <mhalcrow@us.ibm.com>
+:Developers: Michael C. Thompson
+             Kent Yoder
+:Web Site: http://ecryptfs.sf.net
 
 This software is currently undergoing development. Make sure to
 maintain a backup copy of any data you write into eCryptfs.
@@ -19,13 +23,15 @@ SourceForge site:
 http://sourceforge.net/projects/ecryptfs/
 
 Userspace requirements include:
- - David Howells' userspace keyring headers and libraries (version
-   1.0 or higher), obtainable from
-   http://people.redhat.com/~dhowells/keyutils/
- - Libgcrypt
+
+- David Howells' userspace keyring headers and libraries (version
+  1.0 or higher), obtainable from
+  http://people.redhat.com/~dhowells/keyutils/
+- Libgcrypt
 
 
-NOTES
+Notes
+=====
 
 In the beta/experimental releases of eCryptfs, when you upgrade
 eCryptfs, you should copy the files to an unencrypted location and
@@ -33,20 +39,21 @@ then copy the files back into the new eCryptfs mount to migrate the
 files.
 
 
-MOUNT-WIDE PASSPHRASE
+Mount-wide Passphrase
+=====================
 
 Create a new directory into which eCryptfs will write its encrypted
 files (i.e., /root/crypt).  Then, create the mount point directory
-(i.e., /mnt/crypt).  Now it's time to mount eCryptfs:
+(i.e., /mnt/crypt).  Now it's time to mount eCryptfs::
 
-mount -t ecryptfs /root/crypt /mnt/crypt
+    mount -t ecryptfs /root/crypt /mnt/crypt
 
 You should be prompted for a passphrase and a salt (the salt may be
 blank).
 
-Try writing a new file:
+Try writing a new file::
 
-echo "Hello, World" > /mnt/crypt/hello.txt
+    echo "Hello, World" > /mnt/crypt/hello.txt
 
 The operation will complete.  Notice that there is a new file in
 /root/crypt that is at least 12288 bytes in size (depending on your
@@ -59,10 +66,13 @@ keyctl clear @u
 Then umount /mnt/crypt and mount again per the instructions given
 above.
 
-cat /mnt/crypt/hello.txt
+::
+
+    cat /mnt/crypt/hello.txt
 
 
-NOTES
+Notes
+=====
 
 eCryptfs version 0.1 should only be mounted on (1) empty directories
 or (2) directories containing files only created by eCryptfs. If you

Documentation/filesystems/index.rst

@@ -59,6 +59,7 @@ Documentation for filesystem implementations.
    cramfs
    debugfs
    dlmfs
+   ecryptfs
    fuse
    overlayfs
    virtiofs