[ext4] Documentation patch

[Harald Arnesen <skogtun.harald@gmail.com>]

My first patch, hope it goes through ok! 
Applies to 2.6.28-rc6-00184-gd9d060a.

Compare ext4's journalling with anything but ext3's. These use the same
journalling modes, most other Linux filesystems do only metadata
journalling.

Signed-off-by: Harald Arnesen <harald@skogtun.org>

========================================================================
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 174eaff..5bbe79e 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -61,7 +61,7 @@ Note: More extensive information for getting started with ext4 can be
   - When comparing performance with other filesystems, remember that
     ext3/4 by default offers higher data integrity guarantees than most.
     So when comparing with a metadata-only journalling filesystem, such
-    as ext3, use `mount -o data=writeback'.  And you might as well use
+    as jfs or xfs, use `mount -o data=writeback'.  And you might as well use
     `mount -o nobh' too along with it.  Making the journal larger than
     the mke2fs default often helps performance with metadata-intensive
     workloads.
-- 
Hilsen Harald.