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 EXT4_USE_FOR_EXT23 30 bool "Use ext4 for ext2/ext3 file systems" 31 depends on EXT4_FS 32 depends on EXT3_FS=n || EXT2_FS=n 33 default y 34 help 35 Allow the ext4 file system driver code to be used for ext2 or 36 ext3 file system mounts. This allows users to reduce their 37 compiled kernel size by using one file system driver for 38 ext2, ext3, and ext4 file systems. 39 40config EXT4_FS_XATTR 41 bool "Ext4 extended attributes" 42 depends on EXT4_FS 43 default y 44 help 45 Extended attributes are name:value pairs associated with inodes by 46 the kernel or by users (see the attr(5) manual page, or visit 47 <http://acl.bestbits.at/> for details). 48 49 If unsure, say N. 50 51 You need this for POSIX ACL support on ext4. 52 53config EXT4_FS_POSIX_ACL 54 bool "Ext4 POSIX Access Control Lists" 55 depends on EXT4_FS_XATTR 56 select FS_POSIX_ACL 57 help 58 POSIX Access Control Lists (ACLs) support permissions for users and 59 groups beyond the owner/group/world scheme. 60 61 To learn more about Access Control Lists, visit the POSIX ACLs for 62 Linux website <http://acl.bestbits.at/>. 63 64 If you don't know what Access Control Lists are, say N 65 66config EXT4_FS_SECURITY 67 bool "Ext4 Security Labels" 68 depends on EXT4_FS_XATTR 69 help 70 Security labels support alternative access control models 71 implemented by security modules like SELinux. This option 72 enables an extended attribute handler for file security 73 labels in the ext4 filesystem. 74 75 If you are not using a security module that requires using 76 extended attributes for file security labels, say N. 77 78config EXT4_DEBUG 79 bool "EXT4 debugging support" 80 depends on EXT4_FS 81 help 82 Enables run-time debugging support for the ext4 filesystem. 83 84 If you select Y here, then you will be able to turn on debugging 85 with a command such as "echo 1 > /sys/kernel/debug/ext4/mballoc-debug" 86