config EXT4_FS tristate "The Extended 4 (ext4) filesystem" select JBD2 select CRC16 help This is the next generation of the ext3 filesystem. Unlike the change from ext2 filesystem to ext3 filesystem, the on-disk format of ext4 is not forwards compatible with ext3; it is based on extent maps and it supports 48-bit physical block numbers. The ext4 filesystem also supports delayed allocation, persistent preallocation, high resolution time stamps, and a number of other features to improve performance and speed up fsck time. For more information, please see the web pages at http://ext4.wiki.kernel.org. The ext4 filesystem will support mounting an ext3 filesystem; while there will be some performance gains from the delayed allocation and inode table readahead, the best performance gains will require enabling ext4 features in the filesystem, or formatting a new filesystem as an ext4 filesystem initially. To compile this file system support as a module, choose M here. The module will be called ext4. If unsure, say N. config EXT4DEV_COMPAT bool "Enable ext4dev compatibility" depends on EXT4_FS help Starting with 2.6.28, the name of the ext4 filesystem was renamed from ext4dev to ext4. Unfortunately there are some legacy userspace programs (such as klibc's fstype) have "ext4dev" hardcoded. To enable backwards compatibility so that systems that are still expecting to mount ext4 filesystems using ext4dev, chose Y here. This feature will go away by 2.6.31, so please arrange to get your userspace programs fixed! config EXT4_FS_XATTR bool "Ext4 extended attributes" depends on EXT4_FS default y help Extended attributes are name:value pairs associated with inodes by the kernel or by users (see the attr(5) manual page, or visit for details). If unsure, say N. You need this for POSIX ACL support on ext4. config EXT4_FS_POSIX_ACL bool "Ext4 POSIX Access Control Lists" depends on EXT4_FS_XATTR select FS_POSIX_ACL help POSIX Access Control Lists (ACLs) support permissions for users and groups beyond the owner/group/world scheme. To learn more about Access Control Lists, visit the POSIX ACLs for Linux website . If you don't know what Access Control Lists are, say N config EXT4_FS_SECURITY bool "Ext4 Security Labels" depends on EXT4_FS_XATTR help Security labels support alternative access control models implemented by security modules like SELinux. This option enables an extended attribute handler for file security labels in the ext4 filesystem. If you are not using a security module that requires using extended attributes for file security labels, say N.