| 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 | @@ -40,27 +40,35 @@ |
| 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 | @@ -85,10 +93,6 @@ 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 | @@ -115,25 +119,25 @@ 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 | @@ -200,6 +204,10 @@ 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 | @@ -287,7 +295,7 @@ 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 | @@ -297,7 +305,6 @@ 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 | @@ -339,7 +346,7 @@ 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 | + |
| 427 | |
