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Alexey Dobriyan22635ec2009-01-22 10:57:46 +03001config 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
Phillip Lougher681ffe22011-02-28 16:21:34 +00008 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
Phillip Lougher4b676d22010-08-05 23:42:54 +010014 timestamps.
Alexey Dobriyan22635ec2009-01-22 10:57:46 +030015
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
Phillip Lougher637d5c92010-05-31 18:46:29 +010029config SQUASHFS_XATTR
Phillip Lougher01e5b4e2010-05-17 19:39:02 +010030 bool "Squashfs XATTR support"
31 depends on SQUASHFS
Phillip Lougher01e5b4e2010-05-17 19:39:02 +010032 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
Chan Jeong79cb8ce2010-08-05 02:29:59 +010039config SQUASHFS_LZO
40 bool "Include support for LZO compressed file systems"
41 depends on SQUASHFS
42 select LZO_DECOMPRESS
Phillip Lougher4b676d22010-08-05 23:42:54 +010043 help
44 Saying Y here includes support for reading Squashfs file systems
Justin P. Mattock70f23fd2011-05-10 10:16:21 +020045 compressed with LZO compression. LZO compression is mainly
Phillip Lougher4b676d22010-08-05 23:42:54 +010046 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.
Chan Jeong79cb8ce2010-08-05 02:29:59 +010053
Phillip Lougher7a43ae52010-12-09 02:08:31 +000054config 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
Justin P. Mattock70f23fd2011-05-10 10:16:21 +020060 compressed with XZ compression. XZ gives better compression than
Phillip Lougher7a43ae52010-12-09 02:08:31 +000061 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
Alexey Dobriyan22635ec2009-01-22 10:57:46 +030069config SQUASHFS_EMBEDDED
Phillip Lougher4b676d22010-08-05 23:42:54 +010070 bool "Additional option for memory-constrained systems"
Alexey Dobriyan22635ec2009-01-22 10:57:46 +030071 depends on SQUASHFS
Alexey Dobriyan22635ec2009-01-22 10:57:46 +030072 help
73 Saying Y here allows you to specify cache size.
74
75 If unsure, say N.
76
77config 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.