target/linux/generic/patches-2.6.31/006-squashfs_add_lzma.patch

   1 From f49e1efdd179d54e814ff2a8e8f469496583062c Mon Sep 17 00:00:00 2001
   2 From: Phillip Lougher <phillip@lougher.demon.co.uk>
   3 Date: Tue, 20 Oct 2009 10:54:36 +0100
   4 Subject: [PATCH] Squashfs: add LZMA compression
   5
   6 Add support for LZMA compressed filesystems.  This is an initial
   7 implementation.
   8
   9 Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
  10 ---
  11  fs/squashfs/Kconfig        |    5 ++
  12  fs/squashfs/Makefile       |    1 +
  13  fs/squashfs/decompressor.c |    4 +
  14  fs/squashfs/lzma_wrapper.c |  151 ++++++++++++++++++++++++++++++++++++++++++++
  15  fs/squashfs/squashfs.h     |    3 +
  16  5 files changed, 164 insertions(+), 0 deletions(-)
  17  create mode 100644 fs/squashfs/lzma_wrapper.c
  18
  19 --- a/fs/squashfs/Kconfig
  20 +++ b/fs/squashfs/Kconfig
  21 @@ -26,6 +26,11 @@ config SQUASHFS
  22
  23           If unsure, say N.
  24
  25 +config SQUASHFS_LZMA
  26 +       bool "Include support for LZMA compressed file systems"
  27 +       depends on SQUASHFS
  28 +       select DECOMPRESS_LZMA
  29 +
  30  config SQUASHFS_EMBEDDED
  31
  32         bool "Additional option for memory-constrained systems"
  33 --- a/fs/squashfs/Makefile
  34 +++ b/fs/squashfs/Makefile
  35 @@ -5,3 +5,4 @@
  36  obj-$(CONFIG_SQUASHFS) += squashfs.o
  37  squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
  38  squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
  39 +squashfs-$(CONFIG_SQUASHFS_LZMA) += lzma_wrapper.o
  40 --- a/fs/squashfs/decompressor.c
  41 +++ b/fs/squashfs/decompressor.c
  42 @@ -50,7 +50,11 @@ static const struct squashfs_decompresso
  43
  44  static const struct squashfs_decompressor *decompressor[] = {
  45         &squashfs_zlib_comp_ops,
  46 +#ifdef CONFIG_SQUASHFS_LZMA
  47 +       &squashfs_lzma_comp_ops,
  48 +#else
  49         &squashfs_lzma_unsupported_comp_ops,
  50 +#endif
  51         &squashfs_lzo_unsupported_comp_ops,
  52         &squashfs_unknown_comp_ops
  53  };
  54 --- /dev/null
  55 +++ b/fs/squashfs/lzma_wrapper.c
  56 @@ -0,0 +1,151 @@
  57 +/*
  58 + * Squashfs - a compressed read only filesystem for Linux
  59 + *
  60 + * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
  61 + * Phillip Lougher <phillip@lougher.demon.co.uk>
  62 + *
  63 + * This program is free software; you can redistribute it and/or
  64 + * modify it under the terms of the GNU General Public License
  65 + * as published by the Free Software Foundation; either version 2,
  66 + * or (at your option) any later version.
  67 + *
  68 + * This program is distributed in the hope that it will be useful,
  69 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
  70 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  71 + * GNU General Public License for more details.
  72 + *
  73 + * You should have received a copy of the GNU General Public License
  74 + * along with this program; if not, write to the Free Software
  75 + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  76 + *
  77 + * lzma_wrapper.c
  78 + */
  79 +
  80 +#include <asm/unaligned.h>
  81 +#include <linux/buffer_head.h>
  82 +#include <linux/mutex.h>
  83 +#include <linux/vmalloc.h>
  84 +#include <linux/decompress/unlzma.h>
  85 +
  86 +#include "squashfs_fs.h"
  87 +#include "squashfs_fs_sb.h"
  88 +#include "squashfs_fs_i.h"
  89 +#include "squashfs.h"
  90 +#include "decompressor.h"
  91 +
  92 +struct squashfs_lzma {
  93 +       void    *input;
  94 +       void    *output;
  95 +};
  96 +
  97 +/* decompress_unlzma.c is currently non re-entrant... */
  98 +DEFINE_MUTEX(lzma_mutex);
  99 +
 100 +/* decompress_unlzma.c doesn't provide any context in its callbacks... */
 101 +static int lzma_error;
 102 +
 103 +static void error(char *m)
 104 +{
 105 +       ERROR("unlzma error: %s\n", m);
 106 +       lzma_error = 1;
 107 +}
 108 +
 109 +
 110 +static void *lzma_init(struct squashfs_sb_info *msblk)
 111 +{
 112 +       struct squashfs_lzma *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
 113 +       if (stream == NULL)
 114 +               goto failed;
 115 +       stream->input = vmalloc(msblk->block_size);
 116 +       if (stream->input == NULL)
 117 +               goto failed;
 118 +       stream->output = vmalloc(msblk->block_size);
 119 +       if (stream->output == NULL)
 120 +               goto failed2;
 121 +
 122 +       return stream;
 123 +
 124 +failed2:
 125 +       vfree(stream->input);
 126 +failed:
 127 +       ERROR("failed to allocate lzma workspace\n");
 128 +       kfree(stream);
 129 +       return NULL;
 130 +}
 131 +
 132 +
 133 +static void lzma_free(void *strm)
 134 +{
 135 +       struct squashfs_lzma *stream = strm;
 136 +
 137 +       if (stream) {
 138 +               vfree(stream->input);
 139 +               vfree(stream->output);
 140 +       }
 141 +       kfree(stream);
 142 +}
 143 +
 144 +
 145 +static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer,
 146 +       struct buffer_head **bh, int b, int offset, int length, int srclength,
 147 +       int pages)
 148 +{
 149 +       struct squashfs_lzma *stream = msblk->stream;
 150 +       void *buff = stream->input;
 151 +       int avail, i, bytes = length, res;
 152 +
 153 +       mutex_lock(&lzma_mutex);
 154 +
 155 +       for (i = 0; i < b; i++) {
 156 +               wait_on_buffer(bh[i]);
 157 +               if (!buffer_uptodate(bh[i]))
 158 +                       goto block_release;
 159 +
 160 +               avail = min(bytes, msblk->devblksize - offset);
 161 +               memcpy(buff, bh[i]->b_data + offset, avail);
 162 +               buff += avail;
 163 +               bytes -= avail;
 164 +               offset = 0;
 165 +               put_bh(bh[i]);
 166 +       }
 167 +
 168 +       lzma_error = 0;
 169 +       res = unlzma(stream->input, length, NULL, NULL, stream->output, NULL,
 170 +                                                       error);
 171 +       if (res || lzma_error)
 172 +               goto failed;
 173 +
 174 +       /* uncompressed size is stored in the LZMA header (5 byte offset) */
 175 +       res = bytes = get_unaligned_le32(stream->input + 5);
 176 +       for (i = 0, buff = stream->output; bytes && i < pages; i++) {
 177 +               avail = min_t(int, bytes, PAGE_CACHE_SIZE);
 178 +               memcpy(buffer[i], buff, avail);
 179 +               buff += avail;
 180 +               bytes -= avail;
 181 +       }
 182 +       if (bytes)
 183 +               goto failed;
 184 +
 185 +       mutex_unlock(&lzma_mutex);
 186 +       return res;
 187 +
 188 +block_release:
 189 +       for (; i < b; i++)
 190 +               put_bh(bh[i]);
 191 +
 192 +failed:
 193 +       mutex_unlock(&lzma_mutex);
 194 +
 195 +       ERROR("lzma decompression failed, data probably corrupt\n");
 196 +       return -EIO;
 197 +}
 198 +
 199 +const struct squashfs_decompressor squashfs_lzma_comp_ops = {
 200 +       .init = lzma_init,
 201 +       .free = lzma_free,
 202 +       .decompress = lzma_uncompress,
 203 +       .id = LZMA_COMPRESSION,
 204 +       .name = "lzma",
 205 +       .supported = 1
 206 +};
 207 +
 208 --- a/fs/squashfs/squashfs.h
 209 +++ b/fs/squashfs/squashfs.h
 210 @@ -94,3 +94,6 @@ extern const struct address_space_operat
 211
 212  /* zlib_wrapper.c */
 213  extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
 214 +
 215 +/* lzma wrapper.c */
 216 +extern const struct squashfs_decompressor squashfs_lzma_comp_ops;