1*79398b25SAndroid Build Coastguard Worker SQUASHFS 4.2 - A squashed read-only filesystem for Linux 2*79398b25SAndroid Build Coastguard Worker 3*79398b25SAndroid Build Coastguard Worker Copyright 2002-2011 Phillip Lougher <[email protected]> 4*79398b25SAndroid Build Coastguard Worker 5*79398b25SAndroid Build Coastguard Worker Released under the GPL licence (version 2 or later). 6*79398b25SAndroid Build Coastguard Worker 7*79398b25SAndroid Build Coastguard WorkerWelcome to Squashfs 4.2. This is a tools only release, support for Squashfs 8*79398b25SAndroid Build Coastguard Workerfilesystems is in mainline (2.6.29 and later). 9*79398b25SAndroid Build Coastguard Worker 10*79398b25SAndroid Build Coastguard WorkerNew features in Squashfs-tools 4.2 11*79398b25SAndroid Build Coastguard Worker---------------------------------- 12*79398b25SAndroid Build Coastguard Worker 13*79398b25SAndroid Build Coastguard Worker 1. Support for XZ compression 14*79398b25SAndroid Build Coastguard Worker 2. Support for compressor specific options 15*79398b25SAndroid Build Coastguard Worker 16*79398b25SAndroid Build Coastguard WorkerCompatiblity 17*79398b25SAndroid Build Coastguard Worker------------ 18*79398b25SAndroid Build Coastguard Worker 19*79398b25SAndroid Build Coastguard WorkerMksquashfs 4.2 generates 4.0 filesystems. These filesystems are fully 20*79398b25SAndroid Build Coastguard Workercompatible/interchangable with filesystems generated by Mksquashfs 4.0 and are 21*79398b25SAndroid Build Coastguard Workermountable on 2.6.29 and later kernels. 22*79398b25SAndroid Build Coastguard Worker 23*79398b25SAndroid Build Coastguard WorkerXZ compression 24*79398b25SAndroid Build Coastguard Worker-------------- 25*79398b25SAndroid Build Coastguard Worker 26*79398b25SAndroid Build Coastguard WorkerSquashfs now supports XZ compression. 27*79398b25SAndroid Build Coastguard Worker 28*79398b25SAndroid Build Coastguard WorkerXZ support is in 2.6.38 and newer kernels. 29*79398b25SAndroid Build Coastguard Worker 30*79398b25SAndroid Build Coastguard WorkerNew Mksquashfs options 31*79398b25SAndroid Build Coastguard Worker---------------------- 32*79398b25SAndroid Build Coastguard Worker 33*79398b25SAndroid Build Coastguard Worker-X<compressor-option> 34*79398b25SAndroid Build Coastguard Worker 35*79398b25SAndroid Build Coastguard Worker Compression algorithms can now support compression specific options. These 36*79398b25SAndroid Build Coastguard Workeroptions are prefixed by -X, and are passed to the compressor for handling. 37*79398b25SAndroid Build Coastguard Worker 38*79398b25SAndroid Build Coastguard Worker The compression specific options supported by each compressor can be 39*79398b25SAndroid Build Coastguard Workerfound by typing mksquashfs without any arguments. They are displayed at the 40*79398b25SAndroid Build Coastguard Workerend of the help message, e.g. 41*79398b25SAndroid Build Coastguard Worker 42*79398b25SAndroid Build Coastguard WorkerCompressors available and compressor specific options: 43*79398b25SAndroid Build Coastguard Worker gzip (no options) (default) 44*79398b25SAndroid Build Coastguard Worker lzo (no options) 45*79398b25SAndroid Build Coastguard Worker xz 46*79398b25SAndroid Build Coastguard Worker -Xbcj filter1,filter2,...,filterN 47*79398b25SAndroid Build Coastguard Worker Compress using filter1,filter2,...,filterN in turn 48*79398b25SAndroid Build Coastguard Worker (in addition to no filter), and choose the best compression. 49*79398b25SAndroid Build Coastguard Worker Available filters: x86, arm, armthumb, powerpc, sparc, ia64 50*79398b25SAndroid Build Coastguard Worker -Xdict-size <dict-size> 51*79398b25SAndroid Build Coastguard Worker Use <dict-size> as the XZ dictionary size. The dictionary size 52*79398b25SAndroid Build Coastguard Worker can be specified as a percentage of the block size, or as an 53*79398b25SAndroid Build Coastguard Worker absolute value. The dictionary size must be less than or equal 54*79398b25SAndroid Build Coastguard Worker to the block size and 8192 bytes or larger. It must also be 55*79398b25SAndroid Build Coastguard Worker storable in the xz header as either 2^n or as 2^n+2^(n+1). 56*79398b25SAndroid Build Coastguard Worker Example dict-sizes are 75%, 50%, 37.5%, 25%, or 32K, 16K, 8K 57*79398b25SAndroid Build Coastguard Worker etc. 58