fs/squashfs/Kconfig

   1 config SQUASHFS
   2         tristate "SquashFS 4.0 - Squashed file system support"
   3         depends on BLOCK
   4         select ZLIB_INFLATE
   5         help
   6           Saying Y here includes support for SquashFS 4.0 (a Compressed
   7           Read-Only File System).  Squashfs is a highly compressed read-only
   8           filesystem for Linux.  It uses zlib, lzo or xz compression to
   9           compress both files, inodes and directories.  Inodes in the system
  10           are very small and all blocks are packed to minimise data overhead.
  11           Block sizes greater than 4K are supported up to a maximum of 1 Mbytes
  12           (default block size 128K).  SquashFS 4.0 supports 64 bit filesystems
  13           and files (larger than 4GB), full uid/gid information, hard links and
  14           timestamps.
  15
  16           Squashfs is intended for general read-only filesystem use, for
  17           archival use (i.e. in cases where a .tar.gz file may be used), and in
  18           embedded systems where low overhead is needed.  Further information
  19           and tools are available from http://squashfs.sourceforge.net.
  20
  21           If you want to compile this as a module ( = code which can be
  22           inserted in and removed from the running kernel whenever you want),
  23           say M here and read <file:Documentation/modules.txt>.  The module
  24           will be called squashfs.  Note that the root file system (the one
  25           containing the directory /) cannot be compiled as a module.
  26
  27           If unsure, say N.
  28
  29 config SQUASHFS_XATTR
  30         bool "Squashfs XATTR support"
  31         depends on SQUASHFS
  32         help
  33           Saying Y here includes support for extended attributes (xattrs).
  34           Xattrs are name:value pairs associated with inodes by
  35           the kernel or by users (see the attr(5) manual page).
  36
  37           If unsure, say N.
  38
  39 config SQUASHFS_LZO
  40         bool "Include support for LZO compressed file systems"
  41         depends on SQUASHFS
  42         select LZO_DECOMPRESS
  43         help
  44           Saying Y here includes support for reading Squashfs file systems
  45           compressed with LZO compresssion.  LZO compression is mainly
  46           aimed at embedded systems with slower CPUs where the overheads
  47           of zlib are too high.
  48
  49           LZO is not the standard compression used in Squashfs and so most
  50           file systems will be readable without selecting this option.
  51
  52           If unsure, say N.
  53
  54 config SQUASHFS_XZ
  55         bool "Include support for XZ compressed file systems"
  56         depends on SQUASHFS
  57         select XZ_DEC
  58         help
  59           Saying Y here includes support for reading Squashfs file systems
  60           compressed with XZ compresssion.  XZ gives better compression than
  61           the default zlib compression, at the expense of greater CPU and
  62           memory overhead.
  63
  64           XZ is not the standard compression used in Squashfs and so most
  65           file systems will be readable without selecting this option.
  66
  67           If unsure, say N.
  68
  69 config SQUASHFS_EMBEDDED
  70         bool "Additional option for memory-constrained systems"
  71         depends on SQUASHFS
  72         help
  73           Saying Y here allows you to specify cache size.
  74
  75           If unsure, say N.
  76
  77 config SQUASHFS_FRAGMENT_CACHE_SIZE
  78         int "Number of fragments cached" if SQUASHFS_EMBEDDED
  79         depends on SQUASHFS
  80         default "3"
  81         help
  82           By default SquashFS caches the last 3 fragments read from
  83           the filesystem.  Increasing this amount may mean SquashFS
  84           has to re-read fragments less often from disk, at the expense
  85           of extra system memory.  Decreasing this amount will mean
  86           SquashFS uses less memory at the expense of extra reads from disk.
  87
  88           Note there must be at least one cached fragment.  Anything
  89           much more than three will probably not make much difference.