target/linux/generic/patches-2.6.37/521-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 @@ -37,6 +37,11 @@ config SQUASHFS_XATTRS
  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 @@ -5,5 +5,5 @@
  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_XATTRS) += xattr.o xattr_id.o
  40 +squashfs-$(CONFIG_SQUASHFS_LZMA) += lzma_wrapper.o
  41
  42 --- a/fs/squashfs/decompressor.c
  43 +++ b/fs/squashfs/decompressor.c
  44 @@ -50,7 +50,11 @@ static const struct squashfs_decompresso
  45
  46  static const struct squashfs_decompressor *decompressor[] = {
  47         &squashfs_zlib_comp_ops,
  48 +#ifdef CONFIG_SQUASHFS_LZMA
  49 +       &squashfs_lzma_comp_ops,
  50 +#else
  51         &squashfs_lzma_unsupported_comp_ops,
  52 +#endif
  53         &squashfs_lzo_unsupported_comp_ops,
  54         &squashfs_unknown_comp_ops
  55  };
  56 --- /dev/null
  57 +++ b/fs/squashfs/lzma_wrapper.c
  58 @@ -0,0 +1,152 @@
  59 +/*
  60 + * Squashfs - a compressed read only filesystem for Linux
  61 + *
  62 + * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
  63 + * Phillip Lougher <phillip@lougher.demon.co.uk>
  64 + *
  65 + * This program is free software; you can redistribute it and/or
  66 + * modify it under the terms of the GNU General Public License
  67 + * as published by the Free Software Foundation; either version 2,
  68 + * or (at your option) any later version.
  69 + *
  70 + * This program is distributed in the hope that it will be useful,
  71 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
  72 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  73 + * GNU General Public License for more details.
  74 + *
  75 + * You should have received a copy of the GNU General Public License
  76 + * along with this program; if not, write to the Free Software
  77 + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  78 + *
  79 + * lzma_wrapper.c
  80 + */
  81 +
  82 +#include <asm/unaligned.h>
  83 +#include <linux/buffer_head.h>
  84 +#include <linux/mutex.h>
  85 +#include <linux/vmalloc.h>
  86 +#include <linux/decompress/unlzma.h>
  87 +#include <linux/slab.h>
  88 +
  89 +#include "squashfs_fs.h"
  90 +#include "squashfs_fs_sb.h"
  91 +#include "squashfs_fs_i.h"
  92 +#include "squashfs.h"
  93 +#include "decompressor.h"
  94 +
  95 +struct squashfs_lzma {
  96 +       void    *input;
  97 +       void    *output;
  98 +};
  99 +
 100 +/* decompress_unlzma.c is currently non re-entrant... */
 101 +DEFINE_MUTEX(lzma_mutex);
 102 +
 103 +/* decompress_unlzma.c doesn't provide any context in its callbacks... */
 104 +static int lzma_error;
 105 +
 106 +static void error(char *m)
 107 +{
 108 +       ERROR("unlzma error: %s\n", m);
 109 +       lzma_error = 1;
 110 +}
 111 +
 112 +
 113 +static void *lzma_init(struct squashfs_sb_info *msblk)
 114 +{
 115 +       struct squashfs_lzma *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
 116 +       if (stream == NULL)
 117 +               goto failed;
 118 +       stream->input = vmalloc(msblk->block_size);
 119 +       if (stream->input == NULL)
 120 +               goto failed;
 121 +       stream->output = vmalloc(msblk->block_size);
 122 +       if (stream->output == NULL)
 123 +               goto failed2;
 124 +
 125 +       return stream;
 126 +
 127 +failed2:
 128 +       vfree(stream->input);
 129 +failed:
 130 +       ERROR("failed to allocate lzma workspace\n");
 131 +       kfree(stream);
 132 +       return NULL;
 133 +}
 134 +
 135 +
 136 +static void lzma_free(void *strm)
 137 +{
 138 +       struct squashfs_lzma *stream = strm;
 139 +
 140 +       if (stream) {
 141 +               vfree(stream->input);
 142 +               vfree(stream->output);
 143 +       }
 144 +       kfree(stream);
 145 +}
 146 +
 147 +
 148 +static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer,
 149 +       struct buffer_head **bh, int b, int offset, int length, int srclength,
 150 +       int pages)
 151 +{
 152 +       struct squashfs_lzma *stream = msblk->stream;
 153 +       void *buff = stream->input;
 154 +       int avail, i, bytes = length, res;
 155 +
 156 +       mutex_lock(&lzma_mutex);
 157 +
 158 +       for (i = 0; i < b; i++) {
 159 +               wait_on_buffer(bh[i]);
 160 +               if (!buffer_uptodate(bh[i]))
 161 +                       goto block_release;
 162 +
 163 +               avail = min(bytes, msblk->devblksize - offset);
 164 +               memcpy(buff, bh[i]->b_data + offset, avail);
 165 +               buff += avail;
 166 +               bytes -= avail;
 167 +               offset = 0;
 168 +               put_bh(bh[i]);
 169 +       }
 170 +
 171 +       lzma_error = 0;
 172 +       res = unlzma(stream->input, length, NULL, NULL, stream->output, NULL,
 173 +                                                       error);
 174 +       if (res || lzma_error)
 175 +               goto failed;
 176 +
 177 +       /* uncompressed size is stored in the LZMA header (5 byte offset) */
 178 +       res = bytes = get_unaligned_le32(stream->input + 5);
 179 +       for (i = 0, buff = stream->output; bytes && i < pages; i++) {
 180 +               avail = min_t(int, bytes, PAGE_CACHE_SIZE);
 181 +               memcpy(buffer[i], buff, avail);
 182 +               buff += avail;
 183 +               bytes -= avail;
 184 +       }
 185 +       if (bytes)
 186 +               goto failed;
 187 +
 188 +       mutex_unlock(&lzma_mutex);
 189 +       return res;
 190 +
 191 +block_release:
 192 +       for (; i < b; i++)
 193 +               put_bh(bh[i]);
 194 +
 195 +failed:
 196 +       mutex_unlock(&lzma_mutex);
 197 +
 198 +       ERROR("lzma decompression failed, data probably corrupt\n");
 199 +       return -EIO;
 200 +}
 201 +
 202 +const struct squashfs_decompressor squashfs_lzma_comp_ops = {
 203 +       .init = lzma_init,
 204 +       .free = lzma_free,
 205 +       .decompress = lzma_uncompress,
 206 +       .id = LZMA_COMPRESSION,
 207 +       .name = "lzma",
 208 +       .supported = 1
 209 +};
 210 +
 211 --- a/fs/squashfs/squashfs.h
 212 +++ b/fs/squashfs/squashfs.h
 213 @@ -104,3 +104,6 @@ extern const struct xattr_handler *squas
 214
 215  /* zlib_wrapper.c */
 216  extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
 217 +
 218 +/* lzma wrapper.c */
 219 +extern const struct squashfs_decompressor squashfs_lzma_comp_ops;