CONFIG_JBD2 (not configurable)

modulename: jbd2.ko

configname: CONFIG_JBD2

Linux Kernel Configuration
└─>File systems
└─>JBD2
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
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.

source code:
depends
CONFIG_BLOCK

is depended by
CONFIG_EXT3_FS