target/linux/generic-2.6/patches-2.6.31/003-squashfs_add_decompressor_framework.patch

   1 From 327fbf47a419befc6bff74f3ca42d2b6f0841903 Mon Sep 17 00:00:00 2001
   2 From: Phillip Lougher <phillip@lougher.demon.co.uk>
   3 Date: Tue, 6 Oct 2009 04:04:15 +0100
   4 Subject: [PATCH] Squashfs: add a decompressor framework
   5
   6 This adds a decompressor framework which allows multiple compression
   7 algorithms to be cleanly supported.
   8
   9 Also update zlib wrapper and other code to use the new framework.
  10
  11 Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
  12 ---
  13  fs/squashfs/Makefile         |    2 +-
  14  fs/squashfs/block.c          |    6 ++--
  15  fs/squashfs/decompressor.c   |   58 ++++++++++++++++++++++++++++++++++++++++++
  16  fs/squashfs/decompressor.h   |   55 +++++++++++++++++++++++++++++++++++++++
  17  fs/squashfs/squashfs.h       |   14 +++++-----
  18  fs/squashfs/squashfs_fs_sb.h |   41 +++++++++++++++--------------
  19  fs/squashfs/super.c          |   45 ++++++++++++++++++-------------
  20  fs/squashfs/zlib_wrapper.c   |   17 ++++++++++--
  21  8 files changed, 185 insertions(+), 53 deletions(-)
  22  create mode 100644 fs/squashfs/decompressor.c
  23  create mode 100644 fs/squashfs/decompressor.h
  24
  25 --- a/fs/squashfs/Makefile
  26 +++ b/fs/squashfs/Makefile
  27 @@ -4,4 +4,4 @@
  28
  29  obj-$(CONFIG_SQUASHFS) += squashfs.o
  30  squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
  31 -squashfs-y += namei.o super.o symlink.o zlib_wrapper.o
  32 +squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
  33 --- a/fs/squashfs/block.c
  34 +++ b/fs/squashfs/block.c
  35 @@ -36,7 +36,7 @@
  36  #include "squashfs_fs_sb.h"
  37  #include "squashfs_fs_i.h"
  38  #include "squashfs.h"
  39 -
  40 +#include "decompressor.h"
  41  /*
  42   * Read the metadata block length, this is stored in the first two
  43   * bytes of the metadata block.
  44 @@ -151,8 +151,8 @@ int squashfs_read_data(struct super_bloc
  45         }
  46
  47         if (compressed) {
  48 -               length = zlib_uncompress(msblk, buffer, bh, b, offset, length,
  49 -                       srclength, pages);
  50 +               length = squashfs_decompress(msblk, buffer, bh, b, offset,
  51 +                       length, srclength, pages);
  52                 if (length < 0)
  53                         goto read_failure;
  54         } else {
  55 --- /dev/null
  56 +++ b/fs/squashfs/decompressor.c
  57 @@ -0,0 +1,58 @@
  58 +/*
  59 + * Squashfs - a compressed read only filesystem for Linux
  60 + *
  61 + * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
  62 + * Phillip Lougher <phillip@lougher.demon.co.uk>
  63 + *
  64 + * This program is free software; you can redistribute it and/or
  65 + * modify it under the terms of the GNU General Public License
  66 + * as published by the Free Software Foundation; either version 2,
  67 + * or (at your option) any later version.
  68 + *
  69 + * This program is distributed in the hope that it will be useful,
  70 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
  71 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  72 + * GNU General Public License for more details.
  73 + *
  74 + * You should have received a copy of the GNU General Public License
  75 + * along with this program; if not, write to the Free Software
  76 + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  77 + *
  78 + * decompressor.c
  79 + */
  80 +
  81 +#include <linux/types.h>
  82 +#include <linux/mutex.h>
  83 +#include <linux/buffer_head.h>
  84 +
  85 +#include "squashfs_fs.h"
  86 +#include "squashfs_fs_sb.h"
  87 +#include "squashfs_fs_i.h"
  88 +#include "decompressor.h"
  89 +#include "squashfs.h"
  90 +
  91 +/*
  92 + * This file (and decompressor.h) implements a decompressor framework for
  93 + * Squashfs, allowing multiple decompressors to be easily supported
  94 + */
  95 +
  96 +static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
  97 +       NULL, NULL, NULL, 0, "unknown", 0
  98 +};
  99 +
 100 +static const struct squashfs_decompressor *decompressor[] = {
 101 +       &squashfs_zlib_comp_ops,
 102 +       &squashfs_unknown_comp_ops
 103 +};
 104 +
 105 +
 106 +const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
 107 +{
 108 +       int i;
 109 +
 110 +       for (i = 0; decompressor[i]->id; i++)
 111 +               if (id == decompressor[i]->id)
 112 +                       break;
 113 +
 114 +       return decompressor[i];
 115 +}
 116 --- /dev/null
 117 +++ b/fs/squashfs/decompressor.h
 118 @@ -0,0 +1,55 @@
 119 +#ifndef DECOMPRESSOR_H
 120 +#define DECOMPRESSOR_H
 121 +/*
 122 + * Squashfs - a compressed read only filesystem for Linux
 123 + *
 124 + * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
 125 + * Phillip Lougher <phillip@lougher.demon.co.uk>
 126 + *
 127 + * This program is free software; you can redistribute it and/or
 128 + * modify it under the terms of the GNU General Public License
 129 + * as published by the Free Software Foundation; either version 2,
 130 + * or (at your option) any later version.
 131 + *
 132 + * This program is distributed in the hope that it will be useful,
 133 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
 134 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 135 + * GNU General Public License for more details.
 136 + *
 137 + * You should have received a copy of the GNU General Public License
 138 + * along with this program; if not, write to the Free Software
 139 + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 140 + *
 141 + * decompressor.h
 142 + */
 143 +
 144 +struct squashfs_decompressor {
 145 +       void    *(*init)(void);
 146 +       void    (*free)(void *);
 147 +       int     (*decompress)(struct squashfs_sb_info *, void **,
 148 +               struct buffer_head **, int, int, int, int, int);
 149 +       int     id;
 150 +       char    *name;
 151 +       int     supported;
 152 +};
 153 +
 154 +static inline void *squashfs_decompressor_init(struct squashfs_sb_info *msblk)
 155 +{
 156 +       return msblk->decompressor->init();
 157 +}
 158 +
 159 +static inline void squashfs_decompressor_free(struct squashfs_sb_info *msblk,
 160 +       void *s)
 161 +{
 162 +       if (msblk->decompressor)
 163 +               msblk->decompressor->free(s);
 164 +}
 165 +
 166 +static inline int squashfs_decompress(struct squashfs_sb_info *msblk,
 167 +       void **buffer, struct buffer_head **bh, int b, int offset, int length,
 168 +       int srclength, int pages)
 169 +{
 170 +       return msblk->decompressor->decompress(msblk, buffer, bh, b, offset,
 171 +               length, srclength, pages);
 172 +}
 173 +#endif
 174 --- a/fs/squashfs/squashfs.h
 175 +++ b/fs/squashfs/squashfs.h
 176 @@ -51,6 +51,9 @@ extern struct squashfs_cache_entry *squa
 177                                 u64, int);
 178  extern int squashfs_read_table(struct super_block *, void *, u64, int);
 179
 180 +/* decompressor.c */
 181 +extern const struct squashfs_decompressor *squashfs_lookup_decompressor(int);
 182 +
 183  /* export.c */
 184  extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64,
 185                                 unsigned int);
 186 @@ -70,14 +73,8 @@ extern struct inode *squashfs_iget(struc
 187                                 unsigned int);
 188  extern int squashfs_read_inode(struct inode *, long long);
 189
 190 -/* zlib_wrapper.c */
 191 -extern void *zlib_init(void);
 192 -extern void zlib_free(void *);
 193 -extern int zlib_uncompress(struct squashfs_sb_info *, void **,
 194 -                               struct buffer_head **, int, int, int, int, int);
 195 -
 196  /*
 197 - * Inodes and files operations
 198 + * Inodes, files and decompressor operations
 199   */
 200
 201  /* dir.c */
 202 @@ -94,3 +91,6 @@ extern const struct inode_operations squ
 203
 204  /* symlink.c */
 205  extern const struct address_space_operations squashfs_symlink_aops;
 206 +
 207 +/* zlib_wrapper.c */
 208 +extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
 209 --- a/fs/squashfs/squashfs_fs_sb.h
 210 +++ b/fs/squashfs/squashfs_fs_sb.h
 211 @@ -52,25 +52,26 @@ struct squashfs_cache_entry {
 212  };
 213
 214  struct squashfs_sb_info {
 215 -       int                     devblksize;
 216 -       int                     devblksize_log2;
 217 -       struct squashfs_cache   *block_cache;
 218 -       struct squashfs_cache   *fragment_cache;
 219 -       struct squashfs_cache   *read_page;
 220 -       int                     next_meta_index;
 221 -       __le64                  *id_table;
 222 -       __le64                  *fragment_index;
 223 -       unsigned int            *fragment_index_2;
 224 -       struct mutex            read_data_mutex;
 225 -       struct mutex            meta_index_mutex;
 226 -       struct meta_index       *meta_index;
 227 -       void                    *stream;
 228 -       __le64                  *inode_lookup_table;
 229 -       u64                     inode_table;
 230 -       u64                     directory_table;
 231 -       unsigned int            block_size;
 232 -       unsigned short          block_log;
 233 -       long long               bytes_used;
 234 -       unsigned int            inodes;
 235 +       const struct squashfs_decompressor      *decompressor;
 236 +       int                                     devblksize;
 237 +       int                                     devblksize_log2;
 238 +       struct squashfs_cache                   *block_cache;
 239 +       struct squashfs_cache                   *fragment_cache;
 240 +       struct squashfs_cache                   *read_page;
 241 +       int                                     next_meta_index;
 242 +       __le64                                  *id_table;
 243 +       __le64                                  *fragment_index;
 244 +       unsigned int                            *fragment_index_2;
 245 +       struct mutex                            read_data_mutex;
 246 +       struct mutex                            meta_index_mutex;
 247 +       struct meta_index                       *meta_index;
 248 +       void                                    *stream;
 249 +       __le64                                  *inode_lookup_table;
 250 +       u64                                     inode_table;
 251 +       u64                                     directory_table;
 252 +       unsigned int                            block_size;
 253 +       unsigned short                          block_log;
 254 +       long long                               bytes_used;
 255 +       unsigned int                            inodes;
 256  };
 257  #endif
 258 --- a/fs/squashfs/super.c
 259 +++ b/fs/squashfs/super.c
 260 @@ -41,27 +41,35 @@
 261  #include "squashfs_fs_sb.h"
 262  #include "squashfs_fs_i.h"
 263  #include "squashfs.h"
 264 +#include "decompressor.h"
 265
 266  static struct file_system_type squashfs_fs_type;
 267  static struct super_operations squashfs_super_ops;
 268
 269 -static int supported_squashfs_filesystem(short major, short minor, short comp)
 270 +static const struct squashfs_decompressor *supported_squashfs_filesystem(short
 271 +       major, short minor, short id)
 272  {
 273 +       const struct squashfs_decompressor *decompressor;
 274 +
 275         if (major < SQUASHFS_MAJOR) {
 276                 ERROR("Major/Minor mismatch, older Squashfs %d.%d "
 277                         "filesystems are unsupported\n", major, minor);
 278 -               return -EINVAL;
 279 +               return NULL;
 280         } else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
 281                 ERROR("Major/Minor mismatch, trying to mount newer "
 282                         "%d.%d filesystem\n", major, minor);
 283                 ERROR("Please update your kernel\n");
 284 -               return -EINVAL;
 285 +               return NULL;
 286         }
 287
 288 -       if (comp != ZLIB_COMPRESSION)
 289 -               return -EINVAL;
 290 +       decompressor = squashfs_lookup_decompressor(id);
 291 +       if (!decompressor->supported) {
 292 +               ERROR("Filesystem uses \"%s\" compression. This is not "
 293 +                       "supported\n", decompressor->name);
 294 +               return NULL;
 295 +       }
 296
 297 -       return 0;
 298 +       return decompressor;
 299  }
 300
 301
 302 @@ -86,10 +94,6 @@ static int squashfs_fill_super(struct su
 303         }
 304         msblk = sb->s_fs_info;
 305
 306 -       msblk->stream = zlib_init();
 307 -       if (msblk->stream == NULL)
 308 -               goto failure;
 309 -
 310         sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
 311         if (sblk == NULL) {
 312                 ERROR("Failed to allocate squashfs_super_block\n");
 313 @@ -116,25 +120,25 @@ static int squashfs_fill_super(struct su
 314                 goto failed_mount;
 315         }
 316
 317 +       err = -EINVAL;
 318 +
 319         /* Check it is a SQUASHFS superblock */
 320         sb->s_magic = le32_to_cpu(sblk->s_magic);
 321         if (sb->s_magic != SQUASHFS_MAGIC) {
 322                 if (!silent)
 323                         ERROR("Can't find a SQUASHFS superblock on %s\n",
 324                                                 bdevname(sb->s_bdev, b));
 325 -               err = -EINVAL;
 326                 goto failed_mount;
 327         }
 328
 329 -       /* Check the MAJOR & MINOR versions and compression type */
 330 -       err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
 331 +       /* Check the MAJOR & MINOR versions and lookup compression type */
 332 +       msblk->decompressor = supported_squashfs_filesystem(
 333 +                       le16_to_cpu(sblk->s_major),
 334                         le16_to_cpu(sblk->s_minor),
 335                         le16_to_cpu(sblk->compression));
 336 -       if (err < 0)
 337 +       if (msblk->decompressor == NULL)
 338                 goto failed_mount;
 339
 340 -       err = -EINVAL;
 341 -
 342         /*
 343          * Check if there's xattrs in the filesystem.  These are not
 344          * supported in this version, so warn that they will be ignored.
 345 @@ -201,6 +205,10 @@ static int squashfs_fill_super(struct su
 346
 347         err = -ENOMEM;
 348
 349 +       msblk->stream = squashfs_decompressor_init(msblk);
 350 +       if (msblk->stream == NULL)
 351 +               goto failed_mount;
 352 +
 353         msblk->block_cache = squashfs_cache_init("metadata",
 354                         SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
 355         if (msblk->block_cache == NULL)
 356 @@ -288,7 +296,7 @@ failed_mount:
 357         squashfs_cache_delete(msblk->block_cache);
 358         squashfs_cache_delete(msblk->fragment_cache);
 359         squashfs_cache_delete(msblk->read_page);
 360 -       zlib_free(msblk->stream);
 361 +       squashfs_decompressor_free(msblk, msblk->stream);
 362         kfree(msblk->inode_lookup_table);
 363         kfree(msblk->fragment_index);
 364         kfree(msblk->id_table);
 365 @@ -298,7 +306,6 @@ failed_mount:
 366         return err;
 367
 368  failure:
 369 -       zlib_free(msblk->stream);
 370         kfree(sb->s_fs_info);
 371         sb->s_fs_info = NULL;
 372         return -ENOMEM;
 373 @@ -342,7 +349,7 @@ static void squashfs_put_super(struct su
 374                 squashfs_cache_delete(sbi->block_cache);
 375                 squashfs_cache_delete(sbi->fragment_cache);
 376                 squashfs_cache_delete(sbi->read_page);
 377 -               zlib_free(sbi->stream);
 378 +               squashfs_decompressor_free(sbi, sbi->stream);
 379                 kfree(sbi->id_table);
 380                 kfree(sbi->fragment_index);
 381                 kfree(sbi->meta_index);
 382 --- a/fs/squashfs/zlib_wrapper.c
 383 +++ b/fs/squashfs/zlib_wrapper.c
 384 @@ -30,8 +30,9 @@
 385  #include "squashfs_fs_sb.h"
 386  #include "squashfs_fs_i.h"
 387  #include "squashfs.h"
 388 +#include "decompressor.h"
 389
 390 -void *zlib_init()
 391 +static void *zlib_init(void)
 392  {
 393         z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
 394         if (stream == NULL)
 395 @@ -50,7 +51,7 @@ failed:
 396  }
 397
 398
 399 -void zlib_free(void *strm)
 400 +static void zlib_free(void *strm)
 401  {
 402         z_stream *stream = strm;
 403
 404 @@ -60,7 +61,7 @@ void zlib_free(void *strm)
 405  }
 406
 407
 408 -int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
 409 +static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
 410         struct buffer_head **bh, int b, int offset, int length, int srclength,
 411         int pages)
 412  {
 413 @@ -137,3 +138,13 @@ release_mutex:
 414
 415         return -EIO;
 416  }
 417 +
 418 +const struct squashfs_decompressor squashfs_zlib_comp_ops = {
 419 +       .init = zlib_init,
 420 +       .free = zlib_free,
 421 +       .decompress = zlib_uncompress,
 422 +       .id = ZLIB_COMPRESSION,
 423 +       .name = "zlib",
 424 +       .supported = 1
 425 +};
 426 +