ext4: update ext4 documentation

Add documentation for mount options and ioctls to
Documentation/filesystem/ext4.txt, which has not been udpated for some
time.  Also add for ext4 sysfs tunables to the
Documentation/ABI/testing/sysfs-fs-ext4 file, and fix a few
typographical errors in that file.

https://bugzilla.kernel.org/show_bug.cgi?id=9423

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 10 insertions, 3 deletions

diff --git a/Documentation/ABI/testing/sysfs-fs-ext4 b/Documentation/ABI/testing/sysfs-fs-ext4
index 5fb709997d96..f22ac0872ae8 100644
--- a/Documentation/ABI/testing/sysfs-fs-ext4
+++ b/Documentation/ABI/testing/sysfs-fs-ext4
@@ -48,7 +48,7 @@ Description:
                  will have its blocks allocated out of its own unique
                  preallocation pool.
 
-What:           /sys/fs/ext4/<disk>/inode_readahead
+What:           /sys/fs/ext4/<disk>/inode_readahead_blks
 Date:           March 2008
 Contact:        "Theodore Ts'o" <tytso@mit.edu>
 Description:
@@ -85,7 +85,14 @@ Date:		June 2008
 Contact:        "Theodore Ts'o" <tytso@mit.edu>
 Description:
                 Tuning parameter which (if non-zero) controls the goal
-                inode used by the inode allocator in p0reference to
-                all other allocation hueristics.  This is intended for
+                inode used by the inode allocator in preference to
+                all other allocation heuristics.  This is intended for
                 debugging use only, and should be 0 on production
                 systems.
+
+What:           /sys/fs/ext4/<disk>/max_writeback_mb_bump
+Date:           September 2009
+Contact:        "Theodore Ts'o" <tytso@mit.edu>
+Description:
+                The maximum number of megabytes the writeback code will
+                try to write out before move on to another inode.