1config JFFS2_FS
   2        tristate "Journalling Flash File System v2 (JFFS2) support"
   3        select CRC32
   4        depends on MTD
   5        help
   6          JFFS2 is the second generation of the Journalling Flash File System
   7          for use on diskless embedded devices. It provides improved wear
   8          levelling, compression and support for hard links. You cannot use
   9          this on normal block devices, only on 'MTD' devices.
  11          Further information on the design and implementation of JFFS2 is
  12          available at <>.
  14config JFFS2_FS_DEBUG
  15        int "JFFS2 debugging verbosity (0 = quiet, 2 = noisy)"
  16        depends on JFFS2_FS
  17        default "0"
  18        help
  19          This controls the amount of debugging messages produced by the JFFS2
  20          code. Set it to zero for use in production systems. For evaluation,
  21          testing and debugging, it's advisable to set it to one. This will
  22          enable a few assertions and will print debugging messages at the
  23          KERN_DEBUG loglevel, where they won't normally be visible. Level 2
  24          is unlikely to be useful - it enables extra debugging in certain
  25          areas which at one point needed debugging, but when the bugs were
  26          located and fixed, the detailed messages were relegated to level 2.
  28          If reporting bugs, please try to have available a full dump of the
  29          messages at debug level 1 while the misbehaviour was occurring.
  32        bool "JFFS2 write-buffering support"
  33        depends on JFFS2_FS
  34        default y
  35        help
  36          This enables the write-buffering support in JFFS2.
  38          This functionality is required to support JFFS2 on the following
  39          types of flash devices:
  40            - NAND flash
  41            - NOR flash with transparent ECC
  42            - DataFlash
  45        bool "Verify JFFS2 write-buffer reads"
  46        depends on JFFS2_FS_WRITEBUFFER
  47        default n
  48        help
  49          This causes JFFS2 to read back every page written through the
  50          write-buffer, and check for errors.
  52config JFFS2_SUMMARY
  53        bool "JFFS2 summary support (EXPERIMENTAL)"
  54        depends on JFFS2_FS && EXPERIMENTAL
  55        default n
  56        help
  57          This feature makes it possible to use summary information
  58          for faster filesystem mount.
  60          The summary information can be inserted into a filesystem image
  61          by the utility 'sumtool'.
  63          If unsure, say 'N'.
  65config JFFS2_FS_XATTR
  66        bool "JFFS2 XATTR support (EXPERIMENTAL)"
  67        depends on JFFS2_FS && EXPERIMENTAL
  68        default n
  69        help
  70          Extended attributes are name:value pairs associated with inodes by
  71          the kernel or by users (see the attr(5) manual page, or visit
  72          <> for details).
  74          If unsure, say N.
  76config JFFS2_FS_POSIX_ACL
  77        bool "JFFS2 POSIX Access Control Lists"
  78        depends on JFFS2_FS_XATTR
  79        default y
  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.
  85          To learn more about Access Control Lists, visit the Posix ACLs for
  86          Linux website <>.
  88          If you don't know what Access Control Lists are, say N
  90config JFFS2_FS_SECURITY
  91        bool "JFFS2 Security Labels"
  92        depends on JFFS2_FS_XATTR
  93        default y
  94        help
  95          Security labels support alternative access control models
  96          implemented by security modules like SELinux.  This option
  97          enables an extended attribute handler for file security
  98          labels in the jffs2 filesystem.
 100          If you are not using a security module that requires using
 101          extended attributes for file security labels, say N.
 104        bool "Advanced compression options for JFFS2"
 105        depends on JFFS2_FS
 106        default n
 107        help
 108          Enabling this option allows you to explicitly choose which
 109          compression modules, if any, are enabled in JFFS2. Removing
 110          compressors can mean you cannot read existing file systems,
 111          and enabling experimental compressors can mean that you
 112          write a file system which cannot be read by a standard kernel.
 114          If unsure, you should _definitely_ say 'N'.
 116config JFFS2_ZLIB
 117        bool "JFFS2 ZLIB compression support" if JFFS2_COMPRESSION_OPTIONS
 118        select ZLIB_INFLATE
 119        select ZLIB_DEFLATE
 120        depends on JFFS2_FS
 121        default y
 122        help
 123          Zlib is designed to be a free, general-purpose, legally unencumbered,
 124          lossless data-compression library for use on virtually any computer
 125          hardware and operating system. See <> for
 126          further information.
 128          Say 'Y' if unsure.
 130config JFFS2_LZO
 131        bool "JFFS2 LZO compression support" if JFFS2_COMPRESSION_OPTIONS
 132        select LZO_COMPRESS
 133        select LZO_DECOMPRESS
 134        depends on JFFS2_FS
 135        default n
 136        help
 137          minilzo-based compression. Generally works better than Zlib.
 139          This feature was added in July, 2007. Say 'N' if you need
 140          compatibility with older bootloaders or kernels.
 142config JFFS2_RTIME
 143        bool "JFFS2 RTIME compression support" if JFFS2_COMPRESSION_OPTIONS
 144        depends on JFFS2_FS
 145        default y
 146        help
 147          Rtime does manage to recompress already-compressed data. Say 'Y' if unsure.
 149config JFFS2_RUBIN
 150        bool "JFFS2 RUBIN compression support" if JFFS2_COMPRESSION_OPTIONS
 151        depends on JFFS2_FS
 152        default n
 153        help
 154          RUBINMIPS and DYNRUBIN compressors. Say 'N' if unsure.
 157        prompt "JFFS2 default compression mode" if JFFS2_COMPRESSION_OPTIONS
 158        default JFFS2_CMODE_PRIORITY
 159        depends on JFFS2_FS
 160        help
 161          You can set here the default compression mode of JFFS2 from
 162          the available compression modes. Don't touch if unsure.
 164config JFFS2_CMODE_NONE
 165        bool "no compression"
 166        help
 167          Uses no compression.
 170        bool "priority"
 171        help
 172          Tries the compressors in a predefined order and chooses the first
 173          successful one.
 175config JFFS2_CMODE_SIZE
 176        bool "size (EXPERIMENTAL)"
 177        help
 178          Tries all compressors and chooses the one which has the smallest
 179          result.
 182        bool "Favour LZO"
 183        help
 184          Tries all compressors and chooses the one which has the smallest
 185          result but gives some preference to LZO (which has faster
 186          decompression) at the expense of size.
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