1config EXT4_FS 2 tristate "The Extended 4 (ext4) filesystem" 3 select JBD2 4 select CRC16 5 select CRYPTO 6 select CRYPTO_CRC32C 7 help 8 This is the next generation of the ext3 filesystem. 9 10 Unlike the change from ext2 filesystem to ext3 filesystem, 11 the on-disk format of ext4 is not forwards compatible with 12 ext3; it is based on extent maps and it supports 48-bit 13 physical block numbers. The ext4 filesystem also supports delayed 14 allocation, persistent preallocation, high resolution time stamps, 15 and a number of other features to improve performance and speed 16 up fsck time. For more information, please see the web pages at 17 http://ext4.wiki.kernel.org. 18 19 The ext4 filesystem will support mounting an ext3 20 filesystem; while there will be some performance gains from 21 the delayed allocation and inode table readahead, the best 22 performance gains will require enabling ext4 features in the 23 filesystem, or formatting a new filesystem as an ext4 24 filesystem initially. 25 26 To compile this file system support as a module, choose M here. The 27 module will be called ext4. 28 29 If unsure, say N. 30 31config EXT4_USE_FOR_EXT23 32 bool "Use ext4 for ext2/ext3 file systems" 33 depends on EXT4_FS 34 depends on EXT3_FS=n || EXT2_FS=n 35 default y 36 help 37 Allow the ext4 file system driver code to be used for ext2 or 38 ext3 file system mounts. This allows users to reduce their 39 compiled kernel size by using one file system driver for 40 ext2, ext3, and ext4 file systems. 41 42config EXT4_FS_POSIX_ACL 43 bool "Ext4 POSIX Access Control Lists" 44 depends on EXT4_FS 45 select FS_POSIX_ACL 46 help 47 POSIX Access Control Lists (ACLs) support permissions for users and 48 groups beyond the owner/group/world scheme. 49 50 To learn more about Access Control Lists, visit the POSIX ACLs for 51 Linux website <http://acl.bestbits.at/>. 52 53 If you don't know what Access Control Lists are, say N 54 55config EXT4_FS_SECURITY 56 bool "Ext4 Security Labels" 57 depends on EXT4_FS 58 help 59 Security labels support alternative access control models 60 implemented by security modules like SELinux. This option 61 enables an extended attribute handler for file security 62 labels in the ext4 filesystem. 63 64 If you are not using a security module that requires using 65 extended attributes for file security labels, say N. 66 67config EXT4_DEBUG 68 bool "EXT4 debugging support" 69 depends on EXT4_FS 70 help 71 Enables run-time debugging support for the ext4 filesystem. 72 73 If you select Y here, then you will be able to turn on debugging 74 with a command such as: 75 echo 1 > /sys/module/ext4/parameters/mballoc_debug 76