Blame view

fs/squashfs/Kconfig 4.37 KB
22635ec9e   Alexey Dobriyan   fs/Kconfig: move ...
1
2
3
  config SQUASHFS
  	tristate "SquashFS 4.0 - Squashed file system support"
  	depends on BLOCK
22635ec9e   Alexey Dobriyan   fs/Kconfig: move ...
4
5
6
  	help
  	  Saying Y here includes support for SquashFS 4.0 (a Compressed
  	  Read-Only File System).  Squashfs is a highly compressed read-only
681ffe2e4   Phillip Lougher   Squashfs: Update ...
7
8
9
10
11
12
  	  filesystem for Linux.  It uses zlib, lzo or xz compression to
  	  compress both files, inodes and directories.  Inodes in the system
  	  are very small and all blocks are packed to minimise data overhead.
  	  Block sizes greater than 4K are supported up to a maximum of 1 Mbytes
  	  (default block size 128K).  SquashFS 4.0 supports 64 bit filesystems
  	  and files (larger than 4GB), full uid/gid information, hard links and
4b676d2db   Phillip Lougher   Squashfs: update ...
13
  	  timestamps.
22635ec9e   Alexey Dobriyan   fs/Kconfig: move ...
14
15
16
17
18
19
20
21
  
  	  Squashfs is intended for general read-only filesystem use, for
  	  archival use (i.e. in cases where a .tar.gz file may be used), and in
  	  embedded systems where low overhead is needed.  Further information
  	  and tools are available from http://squashfs.sourceforge.net.
  
  	  If you want to compile this as a module ( = code which can be
  	  inserted in and removed from the running kernel whenever you want),
395cf9691   Paul Bolle   doc: fix broken r...
22
23
24
  	  say M here.  The module will be called squashfs.  Note that the root
  	  file system (the one containing the directory /) cannot be compiled
  	  as a module.
22635ec9e   Alexey Dobriyan   fs/Kconfig: move ...
25
26
  
  	  If unsure, say N.
637d5c9a3   Phillip Lougher   Squashfs: Make XA...
27
  config SQUASHFS_XATTR
01e5b4e4e   Phillip Lougher   squashfs: add xat...
28
29
  	bool "Squashfs XATTR support"
  	depends on SQUASHFS
01e5b4e4e   Phillip Lougher   squashfs: add xat...
30
31
32
33
34
35
  	help
  	  Saying Y here includes support for extended attributes (xattrs).
  	  Xattrs are name:value pairs associated with inodes by
  	  the kernel or by users (see the attr(5) manual page).
  
  	  If unsure, say N.
cc6d34971   Phillip Lougher   Squashfs: Make ZL...
36
37
38
39
40
41
42
43
44
45
46
47
  config SQUASHFS_ZLIB
  	bool "Include support for ZLIB compressed file systems"
  	depends on SQUASHFS
  	select ZLIB_INFLATE
  	default y
  	help
  	  ZLIB compression is the standard compression used by Squashfs
  	  file systems.  It offers a good trade-off between compression
  	  achieved and the amount of CPU time and memory necessary to
  	  compress and decompress.
  
  	  If unsure, say Y.
79cb8ced7   Chan Jeong   Squashfs: Add LZO...
48
49
50
51
  config SQUASHFS_LZO
  	bool "Include support for LZO compressed file systems"
  	depends on SQUASHFS
  	select LZO_DECOMPRESS
4b676d2db   Phillip Lougher   Squashfs: update ...
52
53
  	help
  	  Saying Y here includes support for reading Squashfs file systems
70f23fd66   Justin P. Mattock   treewide: fix a f...
54
  	  compressed with LZO compression.  LZO compression is mainly
4b676d2db   Phillip Lougher   Squashfs: update ...
55
56
  	  aimed at embedded systems with slower CPUs where the overheads
  	  of zlib are too high.
79cb8ced7   Chan Jeong   Squashfs: Add LZO...
57

4b676d2db   Phillip Lougher   Squashfs: update ...
58
59
  	  LZO is not the standard compression used in Squashfs and so most
  	  file systems will be readable without selecting this option.
22635ec9e   Alexey Dobriyan   fs/Kconfig: move ...
60

4b676d2db   Phillip Lougher   Squashfs: update ...
61
  	  If unsure, say N.
7a43ae523   Phillip Lougher   Squashfs: Add XZ ...
62
63
64
65
66
67
  config SQUASHFS_XZ
  	bool "Include support for XZ compressed file systems"
  	depends on SQUASHFS
  	select XZ_DEC
  	help
  	  Saying Y here includes support for reading Squashfs file systems
70f23fd66   Justin P. Mattock   treewide: fix a f...
68
  	  compressed with XZ compression.  XZ gives better compression than
7a43ae523   Phillip Lougher   Squashfs: Add XZ ...
69
70
71
72
73
74
75
  	  the default zlib compression, at the expense of greater CPU and
  	  memory overhead.
  
  	  XZ is not the standard compression used in Squashfs and so most
  	  file systems will be readable without selecting this option.
  
  	  If unsure, say N.
7657cacf4   Phillip Lougher   Squashfs: Add an ...
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
  config SQUASHFS_4K_DEVBLK_SIZE
  	bool "Use 4K device block size?"
  	depends on SQUASHFS
  	help
  	  By default Squashfs sets the dev block size (sb_min_blocksize)
  	  to 1K or the smallest block size supported by the block device
  	  (if larger).  This, because blocks are packed together and
  	  unaligned in Squashfs, should reduce latency.
  
  	  This, however, gives poor performance on MTD NAND devices where
  	  the optimal I/O size is 4K (even though the devices can support
  	  smaller block sizes).
  
  	  Using a 4K device block size may also improve overall I/O
  	  performance for some file access patterns (e.g. sequential
  	  accesses of files in filesystem order) on all media.
  
  	  Setting this option will force Squashfs to use a 4K device block
  	  size by default.
  
  	  If unsure, say N.
4b676d2db   Phillip Lougher   Squashfs: update ...
97
98
  config SQUASHFS_EMBEDDED
  	bool "Additional option for memory-constrained systems"
22635ec9e   Alexey Dobriyan   fs/Kconfig: move ...
99
  	depends on SQUASHFS
22635ec9e   Alexey Dobriyan   fs/Kconfig: move ...
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
  	help
  	  Saying Y here allows you to specify cache size.
  
  	  If unsure, say N.
  
  config SQUASHFS_FRAGMENT_CACHE_SIZE
  	int "Number of fragments cached" if SQUASHFS_EMBEDDED
  	depends on SQUASHFS
  	default "3"
  	help
  	  By default SquashFS caches the last 3 fragments read from
  	  the filesystem.  Increasing this amount may mean SquashFS
  	  has to re-read fragments less often from disk, at the expense
  	  of extra system memory.  Decreasing this amount will mean
  	  SquashFS uses less memory at the expense of extra reads from disk.
  
  	  Note there must be at least one cached fragment.  Anything
  	  much more than three will probably not make much difference.