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. 90