integritysetup: support mode=(journal|bitmap|direct)

Add a parameter to the integritytab file to set the mode in which to
open the integrity volume. The mode can be journaled (the default),
bitmap without a journal, or direct mode without a journal or a bitmap.

This change removes the `no-journal' option because it is redundant,
being replaced with `mode=direct'.

Supercedes commit bcc1ee56c, from a week ago, which implemented
`no-journal'.

Resolves #27587

1 files changed, 5 insertions, 2 deletions

diff --git a/man/integritytab.xml b/man/integritytab.xml
index 44da039dde..12ec2933a9 100644
--- a/man/integritytab.xml
+++ b/man/integritytab.xml
@@ -73,10 +73,13 @@
       </varlistentry>
 
       <varlistentry>
-        <term><option>no-journal</option></term>
+        <term><option>mode=(journal|bitmap|direct)</option></term>
 
         <listitem><para>
-        Disable the journal. Corresponds to the "direct writes" mode documented in
+        Enable journaled, bitmapped or direct (passthrough) mode. Journaled mode is the default when this option is not specified.
+        It provides safety against crashes, but can be slow because all data has to be written twice.
+        Bitmap mode is more efficient since it requires only a single write, but it is less reliable because if data corruption happens when the machine crashes, it may not be detected.
+        Direct mode disables the journal and the bitmap. Corresponds to the "direct writes" mode documented in
         <ulink url="https://docs.kernel.org/admin-guide/device-mapper/dm-integrity.html">the dm-integrity documentation</ulink>.
         Note that without a journal, if there is a crash, it is possible that the integrity tags and data will not match. If used, the journal-*
         options below will have no effect if passed.