ext4: Use ext4 file system driver for ext2/ext3 file system mounts

Add a new config option, CONFIG_EXT4_USE_FOR_EXT23 which if enabled,
will cause ext4 to be used for either ext2 or ext3 file system mounts
when ext2 or ext3 is not enabled in the configuration.

This allows minimalist kernel fanatics to drop to file system drivers
from their compiled kernel with out losing functionality.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index 9f2d45d75b1a..a6b4e93833d6 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -26,6 +26,16 @@ config EXT4_FS
 
           If unsure, say N.
 
+config EXT4_USE_FOR_EXT23
+        bool "Use ext4 for ext2/ext3 file systems"
+        depends on !EXT3_FS || !EXT2_FS
+        default y
+        help
+          Allow the ext4 file system driver code to be used for ext2 or
+          ext3 file system mounts.  This allows users to reduce their
+          compiled kernel size by using one file system driver for
+          ext2, ext3, and ext4 file systems.
+
 config EXT4_FS_XATTR
         bool "Ext4 extended attributes"
         depends on EXT4_FS