fs/ext4/Kconfig

   1 # Ext3 configs are here for backward compatibility with old configs which may
   2 # have EXT3_FS set but not EXT4_FS set and thus would result in non-bootable
   3 # kernels after the removal of ext3 driver.
   4 config EXT3_FS
   5         tristate "The Extended 3 (ext3) filesystem"
   6         # These must match EXT4_FS selects...
   7         select EXT4_FS
   8         select JBD2
   9         select CRC16
  10         select CRYPTO
  11         select CRYPTO_CRC32C
  12         help
  13           This config option is here only for backward compatibility. ext3
  14           filesystem is now handled by the ext4 driver.
  15
  16 config EXT3_FS_POSIX_ACL
  17         bool "Ext3 POSIX Access Control Lists"
  18         depends on EXT3_FS
  19         select EXT4_FS_POSIX_ACL
  20         select FS_POSIX_ACL
  21         help
  22           This config option is here only for backward compatibility. ext3
  23           filesystem is now handled by the ext4 driver.
  24
  25 config EXT3_FS_SECURITY
  26         bool "Ext3 Security Labels"
  27         depends on EXT3_FS
  28         select EXT4_FS_SECURITY
  29         help
  30           This config option is here only for backward compatibility. ext3
  31           filesystem is now handled by the ext4 driver.
  32
  33 config EXT4_FS
  34         tristate "The Extended 4 (ext4) filesystem"
  35         # Please update EXT3_FS selects when changing these
  36         select JBD2
  37         select CRC16
  38         select CRYPTO
  39         select CRYPTO_CRC32C
  40         select FS_IOMAP
  41         help
  42           This is the next generation of the ext3 filesystem.
  43
  44           Unlike the change from ext2 filesystem to ext3 filesystem,
  45           the on-disk format of ext4 is not forwards compatible with
  46           ext3; it is based on extent maps and it supports 48-bit
  47           physical block numbers.  The ext4 filesystem also supports delayed
  48           allocation, persistent preallocation, high resolution time stamps,
  49           and a number of other features to improve performance and speed
  50           up fsck time.  For more information, please see the web pages at
  51           http://ext4.wiki.kernel.org.
  52
  53           The ext4 filesystem supports mounting an ext3 filesystem; while there
  54           are some performance gains from the delayed allocation and inode
  55           table readahead, the best performance gains require enabling ext4
  56           features in the filesystem using tune2fs, or formatting a new
  57           filesystem as an ext4 filesystem initially. Without explicit enabling
  58           of ext4 features, the on disk filesystem format stays fully backward
  59           compatible.
  60
  61           To compile this file system support as a module, choose M here. The
  62           module will be called ext4.
  63
  64           If unsure, say N.
  65
  66 config EXT4_USE_FOR_EXT2
  67         bool "Use ext4 for ext2 file systems"
  68         depends on EXT4_FS
  69         depends on EXT2_FS=n
  70         default y
  71         help
  72           Allow the ext4 file system driver code to be used for ext2
  73           file system mounts.  This allows users to reduce their
  74           compiled kernel size by using one file system driver for
  75           ext2, ext3, and ext4 file systems.
  76
  77 config EXT4_FS_POSIX_ACL
  78         bool "Ext4 POSIX Access Control Lists"
  79         depends on EXT4_FS
  80         select FS_POSIX_ACL
  81         help
  82           POSIX Access Control Lists (ACLs) support permissions for users and
  83           groups beyond the owner/group/world scheme.
  84
  85           To learn more about Access Control Lists, visit the POSIX ACLs for
  86           Linux website <http://acl.bestbits.at/>.
  87
  88           If you don't know what Access Control Lists are, say N
  89
  90 config EXT4_FS_SECURITY
  91         bool "Ext4 Security Labels"
  92         depends on EXT4_FS
  93         help
  94           Security labels support alternative access control models
  95           implemented by security modules like SELinux.  This option
  96           enables an extended attribute handler for file security
  97           labels in the ext4 filesystem.
  98
  99           If you are not using a security module that requires using
 100           extended attributes for file security labels, say N.
 101
 102 config EXT4_ENCRYPTION
 103         bool "Ext4 Encryption"
 104         depends on EXT4_FS
 105         select FS_ENCRYPTION
 106         help
 107           Enable encryption of ext4 files and directories.  This
 108           feature is similar to ecryptfs, but it is more memory
 109           efficient since it avoids caching the encrypted and
 110           decrypted pages in the page cache.
 111
 112 config EXT4_FS_ENCRYPTION
 113         bool
 114         default y
 115         depends on EXT4_ENCRYPTION
 116
 117 config EXT4_DEBUG
 118         bool "EXT4 debugging support"
 119         depends on EXT4_FS
 120         help
 121           Enables run-time debugging support for the ext4 filesystem.
 122
 123           If you select Y here, then you will be able to turn on debugging
 124           with a command such as:
 125                 echo 1 > /sys/module/ext4/parameters/mballoc_debug