jbd: config_jbd_debug cannot create /proc entry

The jbd-debug file used to be located in /proc/sys/fs/jbd-debug, but
create_proc_entry() does not do lookups on file names that are more that
one directory deep.  This causes the entry creation to fail and hence, no
proc file is created.

Instead of fixing this on procfs might as well move the jbd2-debug file to
debugfs which would be the preferred location for this kind of tunable.
The new location is now /sys/kernel/debug/jbd/jbd-debug.

[akpm@linux-foundation.org: zillions of cleanups]
Signed-off-by: Jose R. Santos <jrs@us.ibm.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/Kconfig

@@ -220,7 +220,7 @@ config JBD
 
 config JBD_DEBUG
 	bool "JBD (ext3) debugging support"
-	depends on JBD
+	depends on JBD && DEBUG_FS
 	help
 	  If you are using the ext3 journaled file system (or potentially any
 	  other file system/device using JBD), this option allows you to
@@ -229,10 +229,10 @@ config JBD_DEBUG
 	  debugging output will be turned off.
 
 	  If you select Y here, then you will be able to turn on debugging
-	  with "echo N > /proc/sys/fs/jbd-debug", where N is a number between
-	  1 and 5, the higher the number, the more debugging output is
-	  generated.  To turn debugging off again, do
-	  "echo 0 > /proc/sys/fs/jbd-debug".
+	  with "echo N > /sys/kernel/debug/jbd/jbd-debug", where N is a
+	  number between 1 and 5, the higher the number, the more debugging
+	  output is generated.  To turn debugging off again, do
+	  "echo 0 > /sys/kernel/debug/jbd/jbd-debug".
 
 config JBD2
 	tristate