1/* Modified by Broadcom Corp. Portions Copyright (c) Broadcom Corp, 2012. */ 2/* 3 * Squashfs - a compressed read only filesystem for Linux 4 * 5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008 6 * Phillip Lougher <phillip@lougher.demon.co.uk> 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License 10 * as published by the Free Software Foundation; either version 2, 11 * or (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 21 * 22 * super.c 23 */ 24 25/* 26 * This file implements code to read the superblock, read and initialise 27 * in-memory structures at mount time, and all the VFS glue code to register 28 * the filesystem. 29 */ 30 31#include <linux/fs.h> 32#include <linux/vfs.h> 33#include <linux/slab.h> 34#include <linux/mutex.h> 35#include <linux/pagemap.h> 36#include <linux/init.h> 37#include <linux/module.h> 38#include <linux/magic.h> 39#include <linux/xattr.h> 40 41#include "squashfs_fs.h" 42#include "squashfs_fs_sb.h" 43#include "squashfs_fs_i.h" 44#include "squashfs.h" 45#include "decompressor.h" 46#include "xattr.h" 47 48static struct file_system_type squashfs_fs_type; 49static const struct super_operations squashfs_super_ops; 50 51static const struct squashfs_decompressor *supported_squashfs_filesystem(short 52 major, short minor, short id) 53{ 54 const struct squashfs_decompressor *decompressor; 55 56 if (major < SQUASHFS_MAJOR) { 57 ERROR("Major/Minor mismatch, older Squashfs %d.%d " 58 "filesystems are unsupported\n", major, minor); 59 return NULL; 60 } else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) { 61 ERROR("Major/Minor mismatch, trying to mount newer " 62 "%d.%d filesystem\n", major, minor); 63 ERROR("Please update your kernel\n"); 64 return NULL; 65 } 66 67 decompressor = squashfs_lookup_decompressor(id); 68 if (!decompressor->supported) { 69 ERROR("Filesystem uses \"%s\" compression. This is not " 70 "supported\n", decompressor->name); 71 return NULL; 72 } 73 74 return decompressor; 75} 76 77 78static int squashfs_fill_super(struct super_block *sb, void *data, int silent) 79{ 80 struct squashfs_sb_info *msblk; 81 struct squashfs_super_block *sblk = NULL; 82 char b[BDEVNAME_SIZE]; 83 struct inode *root; 84 long long root_inode; 85 unsigned short flags; 86 unsigned int fragments; 87 u64 lookup_table_start, xattr_id_table_start; 88 int err; 89 90 TRACE("Entered squashfs_fill_superblock\n"); 91 92 sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL); 93 if (sb->s_fs_info == NULL) { 94 ERROR("Failed to allocate squashfs_sb_info\n"); 95 return -ENOMEM; 96 } 97 msblk = sb->s_fs_info; 98 99 sblk = kzalloc(sizeof(*sblk), GFP_KERNEL); 100 if (sblk == NULL) { 101 ERROR("Failed to allocate squashfs_super_block\n"); 102 goto failure; 103 } 104 105 msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE); 106 msblk->devblksize_log2 = ffz(~msblk->devblksize); 107 108 mutex_init(&msblk->read_data_mutex); 109 mutex_init(&msblk->meta_index_mutex); 110 111 /* 112 * msblk->bytes_used is checked in squashfs_read_table to ensure reads 113 * are not beyond filesystem end. But as we're using 114 * squashfs_read_table here to read the superblock (including the value 115 * of bytes_used) we need to set it to an initial sensible dummy value 116 */ 117 msblk->bytes_used = sizeof(*sblk); 118 err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk)); 119 120 if (err < 0) { 121 ERROR("unable to read squashfs_super_block\n"); 122 goto failed_mount; 123 } 124 125 err = -EINVAL; 126 127 /* Check it is a SQUASHFS superblock */ 128 sb->s_magic = le32_to_cpu(sblk->s_magic); 129 if (sb->s_magic != SQUASHFS_MAGIC) { 130 if (!silent) 131 ERROR("Can't find a SQUASHFS superblock on %s\n", 132 bdevname(sb->s_bdev, b)); 133 goto failed_mount; 134 } 135 136 /* Check the MAJOR & MINOR versions and lookup compression type */ 137 msblk->decompressor = supported_squashfs_filesystem( 138 le16_to_cpu(sblk->s_major), 139 le16_to_cpu(sblk->s_minor), 140 le16_to_cpu(sblk->compression)); 141 if (msblk->decompressor == NULL) 142 goto failed_mount; 143 144 /* Check the filesystem does not extend beyond the end of the 145 block device */ 146 msblk->bytes_used = le64_to_cpu(sblk->bytes_used); 147 if (msblk->bytes_used < 0 || msblk->bytes_used > 148 i_size_read(sb->s_bdev->bd_inode)) 149 goto failed_mount; 150 151 /* Check block size for sanity */ 152 msblk->block_size = le32_to_cpu(sblk->block_size); 153 if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE) 154 goto failed_mount; 155 156 /* 157 * Check the system page size is not larger than the filesystem 158 * block size (by default 128K). This is currently not supported. 159 */ 160 if (PAGE_CACHE_SIZE > msblk->block_size) { 161 ERROR("Page size > filesystem block size (%d). This is " 162 "currently not supported!\n", msblk->block_size); 163 goto failed_mount; 164 } 165 166 msblk->block_log = le16_to_cpu(sblk->block_log); 167 if (msblk->block_log > SQUASHFS_FILE_MAX_LOG) 168 goto failed_mount; 169 170 /* Check the root inode for sanity */ 171 root_inode = le64_to_cpu(sblk->root_inode); 172 if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE) 173 goto failed_mount; 174 175 msblk->inode_table = le64_to_cpu(sblk->inode_table_start); 176 msblk->directory_table = le64_to_cpu(sblk->directory_table_start); 177 msblk->inodes = le32_to_cpu(sblk->inodes); 178 flags = le16_to_cpu(sblk->flags); 179 180 TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b)); 181 TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags) 182 ? "un" : ""); 183 TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags) 184 ? "un" : ""); 185 TRACE("Filesystem size %lld bytes\n", msblk->bytes_used); 186 TRACE("Block size %d\n", msblk->block_size); 187 TRACE("Number of inodes %d\n", msblk->inodes); 188 TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments)); 189 TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids)); 190 TRACE("sblk->inode_table_start %llx\n", msblk->inode_table); 191 TRACE("sblk->directory_table_start %llx\n", msblk->directory_table); 192 TRACE("sblk->fragment_table_start %llx\n", 193 (u64) le64_to_cpu(sblk->fragment_table_start)); 194 TRACE("sblk->id_table_start %llx\n", 195 (u64) le64_to_cpu(sblk->id_table_start)); 196 197 sb->s_maxbytes = MAX_LFS_FILESIZE; 198 sb->s_flags |= MS_RDONLY; 199 sb->s_op = &squashfs_super_ops; 200 201 err = -ENOMEM; 202 203 msblk->block_cache = squashfs_cache_init("metadata", 204 SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE); 205 if (msblk->block_cache == NULL) 206 goto failed_mount; 207 208 /* Allocate read_page block */ 209 msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size); 210 if (msblk->read_page == NULL) { 211 ERROR("Failed to allocate read_page block\n"); 212 goto failed_mount; 213 } 214 215 msblk->stream = squashfs_decompressor_init(sb, flags); 216 if (IS_ERR(msblk->stream)) { 217 err = PTR_ERR(msblk->stream); 218 msblk->stream = NULL; 219 goto failed_mount; 220 } 221 222 /* Allocate and read id index table */ 223 msblk->id_table = squashfs_read_id_index_table(sb, 224 le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids)); 225 if (IS_ERR(msblk->id_table)) { 226 err = PTR_ERR(msblk->id_table); 227 msblk->id_table = NULL; 228 goto failed_mount; 229 } 230 231 fragments = le32_to_cpu(sblk->fragments); 232 if (fragments == 0) 233 goto allocate_lookup_table; 234 235 msblk->fragment_cache = squashfs_cache_init("fragment", 236 SQUASHFS_CACHED_FRAGMENTS, msblk->block_size); 237 if (msblk->fragment_cache == NULL) { 238 err = -ENOMEM; 239 goto failed_mount; 240 } 241 242 /* Allocate and read fragment index table */ 243 msblk->fragment_index = squashfs_read_fragment_index_table(sb, 244 le64_to_cpu(sblk->fragment_table_start), fragments); 245 if (IS_ERR(msblk->fragment_index)) { 246 err = PTR_ERR(msblk->fragment_index); 247 msblk->fragment_index = NULL; 248 goto failed_mount; 249 } 250 251allocate_lookup_table: 252 lookup_table_start = le64_to_cpu(sblk->lookup_table_start); 253 if (lookup_table_start == SQUASHFS_INVALID_BLK) 254 goto allocate_xattr_table; 255 256 /* Allocate and read inode lookup table */ 257 msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb, 258 lookup_table_start, msblk->inodes); 259 if (IS_ERR(msblk->inode_lookup_table)) { 260 err = PTR_ERR(msblk->inode_lookup_table); 261 msblk->inode_lookup_table = NULL; 262 goto failed_mount; 263 } 264 265 sb->s_export_op = &squashfs_export_ops; 266 267allocate_xattr_table: 268 sb->s_xattr = squashfs_xattr_handlers; 269 xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start); 270 if (xattr_id_table_start == SQUASHFS_INVALID_BLK) 271 goto allocate_root; 272 273 /* Allocate and read xattr id lookup table */ 274 msblk->xattr_id_table = squashfs_read_xattr_id_table(sb, 275 xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids); 276 if (IS_ERR(msblk->xattr_id_table)) { 277 err = PTR_ERR(msblk->xattr_id_table); 278 msblk->xattr_id_table = NULL; 279 if (err != -ENOTSUPP) 280 goto failed_mount; 281 } 282allocate_root: 283 root = new_inode(sb); 284 if (!root) { 285 err = -ENOMEM; 286 goto failed_mount; 287 } 288 289 err = squashfs_read_inode(root, root_inode); 290 if (err) { 291 make_bad_inode(root); 292 iput(root); 293 goto failed_mount; 294 } 295 insert_inode_hash(root); 296 297 sb->s_root = d_alloc_root(root); 298 if (sb->s_root == NULL) { 299 ERROR("Root inode create failed\n"); 300 err = -ENOMEM; 301 iput(root); 302 goto failed_mount; 303 } 304 305 TRACE("Leaving squashfs_fill_super\n"); 306 kfree(sblk); 307 return 0; 308 309failed_mount: 310 squashfs_cache_delete(msblk->block_cache); 311 squashfs_cache_delete(msblk->fragment_cache); 312 squashfs_cache_delete(msblk->read_page); 313 squashfs_decompressor_free(msblk, msblk->stream); 314 kfree(msblk->inode_lookup_table); 315 kfree(msblk->fragment_index); 316 kfree(msblk->id_table); 317 kfree(msblk->xattr_id_table); 318 kfree(sb->s_fs_info); 319 sb->s_fs_info = NULL; 320 kfree(sblk); 321 return err; 322 323failure: 324 kfree(sb->s_fs_info); 325 sb->s_fs_info = NULL; 326 return -ENOMEM; 327} 328 329 330static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf) 331{ 332 struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info; 333 u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev); 334 335 TRACE("Entered squashfs_statfs\n"); 336 337 buf->f_type = SQUASHFS_MAGIC; 338 buf->f_bsize = msblk->block_size; 339 buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1; 340 buf->f_bfree = buf->f_bavail = 0; 341 buf->f_files = msblk->inodes; 342 buf->f_ffree = 0; 343 buf->f_namelen = SQUASHFS_NAME_LEN; 344 buf->f_fsid.val[0] = (u32)id; 345 buf->f_fsid.val[1] = (u32)(id >> 32); 346 347 return 0; 348} 349 350 351static int squashfs_remount(struct super_block *sb, int *flags, char *data) 352{ 353 *flags |= MS_RDONLY; 354 return 0; 355} 356 357 358static void squashfs_put_super(struct super_block *sb) 359{ 360 if (sb->s_fs_info) { 361 struct squashfs_sb_info *sbi = sb->s_fs_info; 362 squashfs_cache_delete(sbi->block_cache); 363 squashfs_cache_delete(sbi->fragment_cache); 364 squashfs_cache_delete(sbi->read_page); 365 squashfs_decompressor_free(sbi, sbi->stream); 366 kfree(sbi->id_table); 367 kfree(sbi->fragment_index); 368 kfree(sbi->meta_index); 369 kfree(sbi->inode_lookup_table); 370 kfree(sbi->xattr_id_table); 371 kfree(sb->s_fs_info); 372 sb->s_fs_info = NULL; 373 } 374} 375 376 377static int squashfs_get_sb(struct file_system_type *fs_type, int flags, 378 const char *dev_name, void *data, 379 struct vfsmount *mnt) 380{ 381 return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super, 382 mnt); 383} 384 385 386static struct kmem_cache *squashfs_inode_cachep; 387 388 389static void init_once(void *foo) 390{ 391 struct squashfs_inode_info *ei = foo; 392 393 inode_init_once(&ei->vfs_inode); 394} 395 396 397static int __init init_inodecache(void) 398{ 399 squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache", 400 sizeof(struct squashfs_inode_info), 0, 401 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, init_once); 402 403 return squashfs_inode_cachep ? 0 : -ENOMEM; 404} 405 406 407static void destroy_inodecache(void) 408{ 409 kmem_cache_destroy(squashfs_inode_cachep); 410} 411 412 413static int __init init_squashfs_fs(void) 414{ 415 int err = init_inodecache(); 416 417 if (err) 418 return err; 419 420 err = register_filesystem(&squashfs_fs_type); 421 if (err) { 422 destroy_inodecache(); 423 return err; 424 } 425 426 printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) " 427 "Phillip Lougher\n"); 428 429 return 0; 430} 431 432 433static void __exit exit_squashfs_fs(void) 434{ 435 unregister_filesystem(&squashfs_fs_type); 436 destroy_inodecache(); 437} 438 439 440static struct inode *squashfs_alloc_inode(struct super_block *sb) 441{ 442 struct squashfs_inode_info *ei = 443 kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL); 444 445 return ei ? &ei->vfs_inode : NULL; 446} 447 448 449static void squashfs_destroy_inode(struct inode *inode) 450{ 451 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode)); 452} 453 454 455static struct file_system_type squashfs_fs_type = { 456 .owner = THIS_MODULE, 457 .name = "squashfs", 458 .get_sb = squashfs_get_sb, 459 .kill_sb = kill_block_super, 460 .fs_flags = FS_REQUIRES_DEV 461}; 462 463static const struct super_operations squashfs_super_ops = { 464 .alloc_inode = squashfs_alloc_inode, 465 .destroy_inode = squashfs_destroy_inode, 466 .statfs = squashfs_statfs, 467 .put_super = squashfs_put_super, 468 .remount_fs = squashfs_remount 469}; 470 471module_init(init_squashfs_fs); 472module_exit(exit_squashfs_fs); 473MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem"); 474MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>"); 475MODULE_LICENSE("GPL"); 476