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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 Lougher4b676d22010-08-05 23:42:54 +01008 filesystem for Linux. It uses zlib/lzo compression to compress both
Alexey Dobriyan22635ec2009-01-22 10:57:46 +03009 files, inodes and directories. Inodes in the system are very small
10 and all blocks are packed to minimise data overhead. Block sizes
11 greater than 4K are supported up to a maximum of 1 Mbytes (default
12 block size 128K). SquashFS 4.0 supports 64 bit filesystems and files
13 (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
32 default n
33 help
34 Saying Y here includes support for extended attributes (xattrs).
35 Xattrs are name:value pairs associated with inodes by
36 the kernel or by users (see the attr(5) manual page).
37
38 If unsure, say N.
39
Chan Jeong79cb8ce2010-08-05 02:29:59 +010040config SQUASHFS_LZO
41 bool "Include support for LZO compressed file systems"
42 depends on SQUASHFS
Phillip Lougher4b676d22010-08-05 23:42:54 +010043 default n
Chan Jeong79cb8ce2010-08-05 02:29:59 +010044 select LZO_DECOMPRESS
Phillip Lougher4b676d22010-08-05 23:42:54 +010045 help
46 Saying Y here includes support for reading Squashfs file systems
47 compressed with LZO compresssion. LZO compression is mainly
48 aimed at embedded systems with slower CPUs where the overheads
49 of zlib are too high.
50
51 LZO is not the standard compression used in Squashfs and so most
52 file systems will be readable without selecting this option.
53
54 If unsure, say N.
Chan Jeong79cb8ce2010-08-05 02:29:59 +010055
Phillip Lougher7a43ae52010-12-09 02:08:31 +000056config SQUASHFS_XZ
57 bool "Include support for XZ compressed file systems"
58 depends on SQUASHFS
59 select XZ_DEC
60 help
61 Saying Y here includes support for reading Squashfs file systems
62 compressed with XZ compresssion. XZ gives better compression than
63 the default zlib compression, at the expense of greater CPU and
64 memory overhead.
65
66 XZ is not the standard compression used in Squashfs and so most
67 file systems will be readable without selecting this option.
68
69 If unsure, say N.
70
Alexey Dobriyan22635ec2009-01-22 10:57:46 +030071config SQUASHFS_EMBEDDED
Phillip Lougher4b676d22010-08-05 23:42:54 +010072 bool "Additional option for memory-constrained systems"
Alexey Dobriyan22635ec2009-01-22 10:57:46 +030073 depends on SQUASHFS
74 default n
75 help
76 Saying Y here allows you to specify cache size.
77
78 If unsure, say N.
79
80config SQUASHFS_FRAGMENT_CACHE_SIZE
81 int "Number of fragments cached" if SQUASHFS_EMBEDDED
82 depends on SQUASHFS
83 default "3"
84 help
85 By default SquashFS caches the last 3 fragments read from
86 the filesystem. Increasing this amount may mean SquashFS
87 has to re-read fragments less often from disk, at the expense
88 of extra system memory. Decreasing this amount will mean
89 SquashFS uses less memory at the expense of extra reads from disk.
90
91 Note there must be at least one cached fragment. Anything
92 much more than three will probably not make much difference.