ocfs2: Support commit= mount option

Mostly taken from ext3. This allows the user to set the jbd commit interval,
in seconds. The default of 5 seconds stays the same, but now users can
easily increase the commit interval. Typically, this would be increased in
order to benefit performance at the expense of data-safety.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt
index e78abdcc59ee..b63bd2d7fcd3 100644
--- a/Documentation/filesystems/ocfs2.txt
+++ b/Documentation/filesystems/ocfs2.txt
@@ -61,3 +61,14 @@ data=writeback		Data ordering is not preserved, data may be written
 preferred_slot=0(*)     During mount, try to use this filesystem slot first. If
                         it is in use by another node, the first empty one found
                         will be chosen. Invalid values will be ignored.
+commit=nrsec    (*)     Ocfs2 can be told to sync all its data and metadata
+                        every 'nrsec' seconds. The default value is 5 seconds.
+                        This means that if you lose your power, you will lose
+                        as much as the latest 5 seconds of work (your
+                        filesystem will not be damaged though, thanks to the
+                        journaling).  This default value (or any low value)
+                        will hurt performance, but it's good for data-safety.
+                        Setting it to 0 will have the same effect as leaving
+                        it at the default (5 seconds).
+                        Setting it to very large values will improve
+                        performance.