ext3/ext4 Documentation: remove bh/nobh since it has been deprecated

Bh and nobh mount option has been deprecated in ext4
(206f7ab4f49a2021fcb8687f25395be77711ddee) and in ext3
(4c4d3901225518ed1a4c938ba15ba09842a00770)
so remove those options from documentation.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>

Documentation/filesystems/ext3.txt

@@ -147,15 +147,6 @@ grpjquota=<file>	during journal replay. They replace the above
 			package for more details
 			(http://sourceforge.net/projects/linuxquota).
 
-bh		(*)	ext3 associates buffer heads to data pages to
-nobh			(a) cache disk block mapping information
-			(b) link pages into transaction to provide
-			    ordering guarantees.
-			"bh" option forces use of buffer heads.
-			"nobh" option tries to avoid associating buffer
-			heads (supported only for "writeback" mode).
-
-
 Specification
 =============
 Ext3 shares all disk implementation with the ext2 filesystem, and adds

Documentation/filesystems/ext4.txt

@@ -68,12 +68,12 @@ Note: More extensive information for getting started with ext4 can be
     '-o barriers=[0|1]' mount option for both ext3 and ext4 filesystems
     for a fair comparison.  When tuning ext3 for best benchmark numbers,
     it is often worthwhile to try changing the data journaling mode; '-o
-    data=writeback,nobh' can be faster for some workloads.  (Note
-    however that running mounted with data=writeback can potentially
-    leave stale data exposed in recently written files in case of an
-    unclean shutdown, which could be a security exposure in some
-    situations.)  Configuring the filesystem with a large journal can
-    also be helpful for metadata-intensive workloads.
+    data=writeback' can be faster for some workloads.  (Note however that
+    running mounted with data=writeback can potentially leave stale data
+    exposed in recently written files in case of an unclean shutdown,
+    which could be a security exposure in some situations.)  Configuring
+    the filesystem with a large journal can also be helpful for
+    metadata-intensive workloads.
 
 2. Features
 ===========
@@ -272,14 +272,6 @@ grpjquota=<file>	during journal replay. They replace the above
 			package for more details
 			(http://sourceforge.net/projects/linuxquota).
 
-bh		(*)	ext4 associates buffer heads to data pages to
-nobh			(a) cache disk block mapping information
-			(b) link pages into transaction to provide
-			    ordering guarantees.
-			"bh" option forces use of buffer heads.
-			"nobh" option tries to avoid associating buffer
-			heads (supported only for "writeback" mode).
-
 stripe=n		Number of filesystem blocks that mballoc will try
 			to use for allocation size and alignment. For RAID5/6
 			systems this should be the number of data
@@ -393,8 +385,7 @@ dioread_nolock		locking. If the dioread_nolock option is specified
 			write and convert the extent to initialized after IO
 			completes. This approach allows ext4 code to avoid
 			using inode mutex, which improves scalability on high
-			speed storages. However this does not work with nobh
-			option and the mount will fail. Nor does it work with
+			speed storages. However this does not work with
 			data journaling and dioread_nolock option will be
 			ignored with kernel warning. Note that dioread_nolock
 			code path is only used for extent-based files.