1config EXT4_FS 2 tristate "The Extended 4 (ext4) filesystem" 3 select JBD2 4 select CRC16 5 help 6 This is the next generation of the ext3 filesystem. 7 8 Unlike the change from ext2 filesystem to ext3 filesystem, 9 the on-disk format of ext4 is not forwards compatible with 10 ext3; it is based on extent maps and it supports 48-bit 11 physical block numbers. The ext4 filesystem also supports delayed 12 allocation, persistent preallocation, high resolution time stamps, 13 and a number of other features to improve performance and speed 14 up fsck time. For more information, please see the web pages at 15 http://ext4.wiki.kernel.org. 16 17 The ext4 filesystem will support mounting an ext3 18 filesystem; while there will be some performance gains from 19 the delayed allocation and inode table readahead, the best 20 performance gains will require enabling ext4 features in the 21 filesystem, or formatting a new filesystem as an ext4 22 filesystem initially. 23 24 To compile this file system support as a module, choose M here. The 25 module will be called ext4. 26 27 If unsure, say N. 28 29config EXT4DEV_COMPAT 30 bool "Enable ext4dev compatibility" 31 depends on EXT4_FS 32 help 33 Starting with 2.6.28, the name of the ext4 filesystem was 34 renamed from ext4dev to ext4. Unfortunately there are some 35 legacy userspace programs (such as klibc's fstype) have 36 "ext4dev" hardcoded. 37 38 To enable backwards compatibility so that systems that are 39 still expecting to mount ext4 filesystems using ext4dev, 40 chose Y here. This feature will go away by 2.6.31, so 41 please arrange to get your userspace programs fixed! 42 43config EXT4_FS_XATTR 44 bool "Ext4 extended attributes" 45 depends on EXT4_FS 46 default y 47 help 48 Extended attributes are name:value pairs associated with inodes by 49 the kernel or by users (see the attr(5) manual page, or visit 50 <http://acl.bestbits.at/> for details). 51 52 If unsure, say N. 53 54 You need this for POSIX ACL support on ext4. 55 56config EXT4_FS_POSIX_ACL 57 bool "Ext4 POSIX Access Control Lists" 58 depends on EXT4_FS_XATTR 59 select FS_POSIX_ACL 60 help 61 POSIX Access Control Lists (ACLs) support permissions for users and 62 groups beyond the owner/group/world scheme. 63 64 To learn more about Access Control Lists, visit the POSIX ACLs for 65 Linux website <http://acl.bestbits.at/>. 66 67 If you don't know what Access Control Lists are, say N 68 69config EXT4_FS_SECURITY 70 bool "Ext4 Security Labels" 71 depends on EXT4_FS_XATTR 72 help 73 Security labels support alternative access control models 74 implemented by security modules like SELinux. This option 75 enables an extended attribute handler for file security 76 labels in the ext4 filesystem. 77 78 If you are not using a security module that requires using 79 extended attributes for file security labels, say N. 80