From f49e1efdd179d54e814ff2a8e8f469496583062c Mon Sep 17 00:00:00 2001 From: Phillip Lougher <phillip@lougher.demon.co.uk> Date: Tue, 20 Oct 2009 10:54:36 +0100 Subject: [PATCH] Squashfs: add LZMA compression Add support for LZMA compressed filesystems. This is an initial implementation. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk> --- fs/squashfs/Kconfig | 5 ++ fs/squashfs/Makefile | 1 + fs/squashfs/decompressor.c | 4 + fs/squashfs/lzma_wrapper.c | 151 ++++++++++++++++++++++++++++++++++++++++++++ fs/squashfs/squashfs.h | 3 + 5 files changed, 164 insertions(+), 0 deletions(-) create mode 100644 fs/squashfs/lzma_wrapper.c --- a/fs/squashfs/Kconfig +++ b/fs/squashfs/Kconfig @@ -26,6 +26,11 @@ config SQUASHFS If unsure, say N. +config SQUASHFS_LZMA + bool "Include support for LZMA compressed file systems" + depends on SQUASHFS + select DECOMPRESS_LZMA + config SQUASHFS_EMBEDDED bool "Additional option for memory-constrained systems" --- a/fs/squashfs/Makefile +++ b/fs/squashfs/Makefile @@ -5,3 +5,4 @@ obj-$(CONFIG_SQUASHFS) += squashfs.o squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o +squashfs-$(CONFIG_SQUASHFS_LZMA) += lzma_wrapper.o --- a/fs/squashfs/decompressor.c +++ b/fs/squashfs/decompressor.c @@ -50,7 +50,11 @@ static const struct squashfs_decompresso static const struct squashfs_decompressor *decompressor[] = { &squashfs_zlib_comp_ops, +#ifdef CONFIG_SQUASHFS_LZMA + &squashfs_lzma_comp_ops, +#else &squashfs_lzma_unsupported_comp_ops, +#endif &squashfs_lzo_unsupported_comp_ops, &squashfs_unknown_comp_ops }; --- /dev/null +++ b/fs/squashfs/lzma_wrapper.c @@ -0,0 +1,151 @@ +/* + * Squashfs - a compressed read only filesystem for Linux + * + * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 + * Phillip Lougher <phillip@lougher.demon.co.uk> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2, + * or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * lzma_wrapper.c + */ + +#include <asm/unaligned.h> +#include <linux/buffer_head.h> +#include <linux/mutex.h> +#include <linux/vmalloc.h> +#include <linux/decompress/unlzma.h> + +#include "squashfs_fs.h" +#include "squashfs_fs_sb.h" +#include "squashfs_fs_i.h" +#include "squashfs.h" +#include "decompressor.h" + +struct squashfs_lzma { + void *input; + void *output; +}; + +/* decompress_unlzma.c is currently non re-entrant... */ +DEFINE_MUTEX(lzma_mutex); + +/* decompress_unlzma.c doesn't provide any context in its callbacks... */ +static int lzma_error; + +static void error(char *m) +{ + ERROR("unlzma error: %s\n", m); + lzma_error = 1; +} + + +static void *lzma_init(struct squashfs_sb_info *msblk) +{ + struct squashfs_lzma *stream = kzalloc(sizeof(*stream), GFP_KERNEL); + if (stream == NULL) + goto failed; + stream->input = vmalloc(msblk->block_size); + if (stream->input == NULL) + goto failed; + stream->output = vmalloc(msblk->block_size); + if (stream->output == NULL) + goto failed2; + + return stream; + +failed2: + vfree(stream->input); +failed: + ERROR("failed to allocate lzma workspace\n"); + kfree(stream); + return NULL; +} + + +static void lzma_free(void *strm) +{ + struct squashfs_lzma *stream = strm; + + if (stream) { + vfree(stream->input); + vfree(stream->output); + } + kfree(stream); +} + + +static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer, + struct buffer_head **bh, int b, int offset, int length, int srclength, + int pages) +{ + struct squashfs_lzma *stream = msblk->stream; + void *buff = stream->input; + int avail, i, bytes = length, res; + + mutex_lock(&lzma_mutex); + + for (i = 0; i < b; i++) { + wait_on_buffer(bh[i]); + if (!buffer_uptodate(bh[i])) + goto block_release; + + avail = min(bytes, msblk->devblksize - offset); + memcpy(buff, bh[i]->b_data + offset, avail); + buff += avail; + bytes -= avail; + offset = 0; + put_bh(bh[i]); + } + + lzma_error = 0; + res = unlzma(stream->input, length, NULL, NULL, stream->output, NULL, + error); + if (res || lzma_error) + goto failed; + + /* uncompressed size is stored in the LZMA header (5 byte offset) */ + res = bytes = get_unaligned_le32(stream->input + 5); + for (i = 0, buff = stream->output; bytes && i < pages; i++) { + avail = min_t(int, bytes, PAGE_CACHE_SIZE); + memcpy(buffer[i], buff, avail); + buff += avail; + bytes -= avail; + } + if (bytes) + goto failed; + + mutex_unlock(&lzma_mutex); + return res; + +block_release: + for (; i < b; i++) + put_bh(bh[i]); + +failed: + mutex_unlock(&lzma_mutex); + + ERROR("lzma decompression failed, data probably corrupt\n"); + return -EIO; +} + +const struct squashfs_decompressor squashfs_lzma_comp_ops = { + .init = lzma_init, + .free = lzma_free, + .decompress = lzma_uncompress, + .id = LZMA_COMPRESSION, + .name = "lzma", + .supported = 1 +}; + --- a/fs/squashfs/squashfs.h +++ b/fs/squashfs/squashfs.h @@ -94,3 +94,6 @@ extern const struct address_space_operat /* zlib_wrapper.c */ extern const struct squashfs_decompressor squashfs_zlib_comp_ops; + +/* lzma wrapper.c */ +extern const struct squashfs_decompressor squashfs_lzma_comp_ops;