[PATCH] jbd2: enable building of jbd2 and have ext4 use it rather than jbd

Reworked from a patch by Mingming Cao and Randy Dunlap

Signed-off-By: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 40 insertions, 8 deletions

diff --git a/fs/Kconfig b/fs/Kconfig
index ac9ba1c30935..db4d13324c36 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -143,24 +143,24 @@ config EXT3_FS_SECURITY
 config EXT4DEV_FS
         tristate "Ext4dev/ext4 extended fs support development (EXPERIMENTAL)"
         depends on EXPERIMENTAL
-        select JBD
-        help
+        select JBD2
+        help
           Ext4dev is a predecessor filesystem of the next generation
           extended fs ext4, based on ext3 filesystem code. It will be
           renamed ext4 fs later, once ext4dev is mature and stabilized.
 
-          Unlike the change from ext2 filesystem to ext3 filesystem,
-          the on-disk format of ext4dev is not the same as ext3 any more:
+          Unlike the change from ext2 filesystem to ext3 filesystem,
+          the on-disk format of ext4dev is not the same as ext3 any more:
           it is based on extent maps and it supports 48-bit physical block
-          numbers. These combined on-disk format changes will allow
+          numbers. These combined on-disk format changes will allow
           ext4dev/ext4 to handle more than 16 TB filesystem volumes --
           a hard limit that ext3 cannot overcome without changing the
-          on-disk format.
+          on-disk format.
 
           Other than extent maps and 48-bit block numbers, ext4dev also is
-          likely to have other new features such as persistent preallocation,
+          likely to have other new features such as persistent preallocation,
           high resolution time stamps, and larger file support etc.  These
-          features will be added to ext4dev gradually.
+          features will be added to ext4dev gradually.
 
           To compile this file system support as a module, choose M here. The
           module will be called ext4dev.  Be aware, however, that the filesystem
@@ -239,6 +239,38 @@ config JBD_DEBUG
           generated.  To turn debugging off again, do
           "echo 0 > /proc/sys/fs/jbd-debug".
 
+config JBD2
+        tristate
+        help
+          This is a generic journaling layer for block devices that support
+          both 32-bit and 64-bit block numbers.  It is currently used by
+          the ext4dev/ext4 filesystem, but it could also be used to add
+          journal support to other file systems or block devices such
+          as RAID or LVM.
+
+          If you are using ext4dev/ext4, you need to say Y here. If you are not
+          using ext4dev/ext4 then you will probably want to say N.
+
+          To compile this device as a module, choose M here. The module will be
+          called jbd2.  If you are compiling ext4dev/ext4 into the kernel,
+          you cannot compile this code as a module.
+
+config JBD2_DEBUG
+        bool "JBD2 (ext4dev/ext4) debugging support"
+        depends on JBD2
+        help
+          If you are using the ext4dev/ext4 journaled file system (or
+          potentially any other filesystem/device using JBD2), this option
+          allows you to enable debugging output while the system is running,
+          in order to help track down any problems you are having.
+          By default, the 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/jbd2-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/jbd2-debug".
+
 config FS_MBCACHE
 # Meta block cache for Extended Attributes (ext2/ext3/ext4)
         tristate