| config EXT4_FS |
| tristate "The Extended 4 (ext4) filesystem" |
| select JBD2 |
| select CRC16 |
| select CRYPTO |
| select CRYPTO_CRC32C |
| 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 EXT4_USE_FOR_EXT23 |
| bool "Use ext4 for ext2/ext3 file systems" |
| depends on EXT4_FS |
| depends on EXT3_FS=n || EXT2_FS=n |
| 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_POSIX_ACL |
| bool "Ext4 POSIX Access Control Lists" |
| depends on EXT4_FS |
| 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 <http://acl.bestbits.at/>. |
| |
| If you don't know what Access Control Lists are, say N |
| |
| config EXT4_FS_SECURITY |
| bool "Ext4 Security Labels" |
| depends on EXT4_FS |
| 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. |
| |
| config EXT4_ENCRYPTION |
| tristate "Ext4 Encryption" |
| depends on EXT4_FS |
| select CRYPTO_AES |
| select CRYPTO_CBC |
| select CRYPTO_ECB |
| select CRYPTO_XTS |
| select CRYPTO_CTS |
| select CRYPTO_CTR |
| select CRYPTO_SHA256 |
| select KEYS |
| select ENCRYPTED_KEYS |
| help |
| Enable encryption of ext4 files and directories. This |
| feature is similar to ecryptfs, but it is more memory |
| efficient since it avoids caching the encrypted and |
| decrypted pages in the page cache. |
| |
| config EXT4_FS_ENCRYPTION |
| bool |
| default y |
| depends on EXT4_ENCRYPTION |
| |
| config EXT4_DEBUG |
| bool "EXT4 debugging support" |
| depends on EXT4_FS |
| help |
| Enables run-time debugging support for the ext4 filesystem. |
| |
| If you select Y here, then you will be able to turn on debugging |
| with a command such as: |
| echo 1 > /sys/module/ext4/parameters/mballoc_debug |
