[linux.git] / fs / squashfs / Kconfig

config SQUASHFS
	tristate "SquashFS 4.0 - Squashed file system support"
	depends on BLOCK
	select ZLIB_INFLATE
	help
	  Saying Y here includes support for SquashFS 4.0 (a Compressed
	  Read-Only File System).  Squashfs is a highly compressed read-only
	  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
	  timestamps.

	  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),
	  say M here and read <file:Documentation/modules.txt>.  The module
	  will be called squashfs.  Note that the root file system (the one
	  containing the directory /) cannot be compiled as a module.

	  If unsure, say N.

config SQUASHFS_XATTR
	bool "Squashfs XATTR support"
	depends on SQUASHFS
	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.

config SQUASHFS_LZO
	bool "Include support for LZO compressed file systems"
	depends on SQUASHFS
	select LZO_DECOMPRESS
	help
	  Saying Y here includes support for reading Squashfs file systems
	  compressed with LZO compression.  LZO compression is mainly
	  aimed at embedded systems with slower CPUs where the overheads
	  of zlib are too high.

	  LZO is not the standard compression used in Squashfs and so most
	  file systems will be readable without selecting this option.

	  If unsure, say N.

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
	  compressed with XZ compression.  XZ gives better compression than
	  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.

config SQUASHFS_EMBEDDED
	bool "Additional option for memory-constrained systems"
	depends on SQUASHFS
	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.
Commit	Line	Data
22635ec9 AD	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
681ffe2e PL	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
4b676d2d	14	timestamps.
22635ec9 AD	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
637d5c9a	29	config SQUASHFS_XATTR
01e5b4e4 PL	30	bool "Squashfs XATTR support"
01e5b4e4 PL	31	depends on SQUASHFS
01e5b4e4 PL	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
79cb8ced CJ	39	config SQUASHFS_LZO
	40	bool "Include support for LZO compressed file systems"
	41	depends on SQUASHFS
	42	select LZO_DECOMPRESS
4b676d2d PL	43	help
4b676d2d PL	44	Saying Y here includes support for reading Squashfs file systems
70f23fd6	45	compressed with LZO compression. LZO compression is mainly
4b676d2d PL	46	aimed at embedded systems with slower CPUs where the overheads
4b676d2d PL	47	of zlib are too high.
79cb8ced	48
4b676d2d PL	49	LZO is not the standard compression used in Squashfs and so most
4b676d2d PL	50	file systems will be readable without selecting this option.
22635ec9	51
4b676d2d PL	52	If unsure, say N.
4b676d2d PL	53
7a43ae52 PL	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
70f23fd6	60	compressed with XZ compression. XZ gives better compression than
7a43ae52 PL	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
4b676d2d PL	69	config SQUASHFS_EMBEDDED
4b676d2d PL	70	bool "Additional option for memory-constrained systems"
22635ec9	71	depends on SQUASHFS
22635ec9 AD	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.