| Alexey Dobriyan | 6da0b38 | 2008-10-20 22:28:45 +0400 | [diff] [blame] | 1 | config 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 |
| Matt LaPlante | 692105b | 2009-01-26 11:12:25 +0100 | [diff] [blame] | 21 | filesystem, or formatting a new filesystem as an ext4 |
| Alexey Dobriyan | 6da0b38 | 2008-10-20 22:28:45 +0400 | [diff] [blame] | 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 | |
| 29 | config 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, |
| Manish Katiyar | 43b3852 | 2009-07-27 21:38:17 -0400 | [diff] [blame] | 40 | choose Y here. This feature will go away by 2.6.31, so |
| Alexey Dobriyan | 6da0b38 | 2008-10-20 22:28:45 +0400 | [diff] [blame] | 41 | please arrange to get your userspace programs fixed! |
| 42 | |
| 43 | config 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 | |
| 56 | config 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 | |
| 69 | config 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. |
| Theodore Ts'o | 6ba495e | 2009-09-18 13:38:55 -0400 | [diff] [blame^] | 80 | |
| 81 | config EXT4_DEBUG |
| 82 | bool "EXT4 debugging support" |
| 83 | depends on EXT4_FS |
| 84 | help |
| 85 | Enables run-time debugging support for the ext4 filesystem. |
| 86 | |
| 87 | If you select Y here, then you will be able to turn on debugging |
| 88 | with a command such as "echo 1 > /sys/kernel/debug/ext4/mballoc-debug" |