1 // SPDX-License-Identifier: GPL-2.0-or-later 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@squashfs.org.uk> 7 * 8 * super.c 9 */ 10 11 /* 12 * This file implements code to read the superblock, read and initialise 13 * in-memory structures at mount time, and all the VFS glue code to register 14 * the filesystem. 15 */ 16 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 19 #include <linux/blkdev.h> 20 #include <linux/fs.h> 21 #include <linux/fs_context.h> 22 #include <linux/fs_parser.h> 23 #include <linux/vfs.h> 24 #include <linux/slab.h> 25 #include <linux/mutex.h> 26 #include <linux/seq_file.h> 27 #include <linux/pagemap.h> 28 #include <linux/init.h> 29 #include <linux/module.h> 30 #include <linux/magic.h> 31 #include <linux/xattr.h> 32 33 #include "squashfs_fs.h" 34 #include "squashfs_fs_sb.h" 35 #include "squashfs_fs_i.h" 36 #include "squashfs.h" 37 #include "decompressor.h" 38 #include "xattr.h" 39 40 static struct file_system_type squashfs_fs_type; 41 static const struct super_operations squashfs_super_ops; 42 43 enum Opt_errors { 44 Opt_errors_continue, 45 Opt_errors_panic, 46 }; 47 48 enum squashfs_param { 49 Opt_errors, 50 Opt_threads, 51 }; 52 53 struct squashfs_mount_opts { 54 enum Opt_errors errors; 55 const struct squashfs_decompressor_thread_ops *thread_ops; 56 int thread_num; 57 }; 58 59 static const struct constant_table squashfs_param_errors[] = { 60 {"continue", Opt_errors_continue }, 61 {"panic", Opt_errors_panic }, 62 {} 63 }; 64 65 static const struct fs_parameter_spec squashfs_fs_parameters[] = { 66 fsparam_enum("errors", Opt_errors, squashfs_param_errors), 67 fsparam_string("threads", Opt_threads), 68 {} 69 }; 70 71 72 static int squashfs_parse_param_threads_str(const char *str, struct squashfs_mount_opts *opts) 73 { 74 #ifdef CONFIG_SQUASHFS_CHOICE_DECOMP_BY_MOUNT 75 if (strcmp(str, "single") == 0) { 76 opts->thread_ops = &squashfs_decompressor_single; 77 return 0; 78 } 79 if (strcmp(str, "multi") == 0) { 80 opts->thread_ops = &squashfs_decompressor_multi; 81 return 0; 82 } 83 if (strcmp(str, "percpu") == 0) { 84 opts->thread_ops = &squashfs_decompressor_percpu; 85 return 0; 86 } 87 #endif 88 return -EINVAL; 89 } 90 91 static int squashfs_parse_param_threads_num(const char *str, struct squashfs_mount_opts *opts) 92 { 93 #ifdef CONFIG_SQUASHFS_MOUNT_DECOMP_THREADS 94 int ret; 95 unsigned long num; 96 97 ret = kstrtoul(str, 0, &num); 98 if (ret != 0) 99 return -EINVAL; 100 if (num > 1) { 101 opts->thread_ops = &squashfs_decompressor_multi; 102 if (num > opts->thread_ops->max_decompressors()) 103 return -EINVAL; 104 opts->thread_num = (int)num; 105 return 0; 106 } 107 #ifdef CONFIG_SQUASHFS_DECOMP_SINGLE 108 if (num == 1) { 109 opts->thread_ops = &squashfs_decompressor_single; 110 opts->thread_num = 1; 111 return 0; 112 } 113 #endif 114 #endif /* !CONFIG_SQUASHFS_MOUNT_DECOMP_THREADS */ 115 return -EINVAL; 116 } 117 118 static int squashfs_parse_param_threads(const char *str, struct squashfs_mount_opts *opts) 119 { 120 int ret = squashfs_parse_param_threads_str(str, opts); 121 122 if (ret == 0) 123 return ret; 124 return squashfs_parse_param_threads_num(str, opts); 125 } 126 127 static int squashfs_parse_param(struct fs_context *fc, struct fs_parameter *param) 128 { 129 struct squashfs_mount_opts *opts = fc->fs_private; 130 struct fs_parse_result result; 131 int opt; 132 133 opt = fs_parse(fc, squashfs_fs_parameters, param, &result); 134 if (opt < 0) 135 return opt; 136 137 switch (opt) { 138 case Opt_errors: 139 opts->errors = result.uint_32; 140 break; 141 case Opt_threads: 142 if (squashfs_parse_param_threads(param->string, opts) != 0) 143 return -EINVAL; 144 break; 145 default: 146 return -EINVAL; 147 } 148 149 return 0; 150 } 151 152 static const struct squashfs_decompressor *supported_squashfs_filesystem( 153 struct fs_context *fc, 154 short major, short minor, short id) 155 { 156 const struct squashfs_decompressor *decompressor; 157 158 if (major < SQUASHFS_MAJOR) { 159 errorf(fc, "Major/Minor mismatch, older Squashfs %d.%d " 160 "filesystems are unsupported", major, minor); 161 return NULL; 162 } else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) { 163 errorf(fc, "Major/Minor mismatch, trying to mount newer " 164 "%d.%d filesystem", major, minor); 165 errorf(fc, "Please update your kernel"); 166 return NULL; 167 } 168 169 decompressor = squashfs_lookup_decompressor(id); 170 if (!decompressor->supported) { 171 errorf(fc, "Filesystem uses \"%s\" compression. This is not supported", 172 decompressor->name); 173 return NULL; 174 } 175 176 return decompressor; 177 } 178 179 180 static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc) 181 { 182 struct squashfs_mount_opts *opts = fc->fs_private; 183 struct squashfs_sb_info *msblk; 184 struct squashfs_super_block *sblk = NULL; 185 struct inode *root; 186 long long root_inode; 187 unsigned short flags; 188 unsigned int fragments; 189 u64 lookup_table_start, xattr_id_table_start, next_table; 190 int err; 191 192 TRACE("Entered squashfs_fill_superblock\n"); 193 194 sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL); 195 if (sb->s_fs_info == NULL) { 196 ERROR("Failed to allocate squashfs_sb_info\n"); 197 return -ENOMEM; 198 } 199 msblk = sb->s_fs_info; 200 msblk->thread_ops = opts->thread_ops; 201 202 msblk->panic_on_errors = (opts->errors == Opt_errors_panic); 203 204 msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE); 205 msblk->devblksize_log2 = ffz(~msblk->devblksize); 206 207 mutex_init(&msblk->meta_index_mutex); 208 209 /* 210 * msblk->bytes_used is checked in squashfs_read_table to ensure reads 211 * are not beyond filesystem end. But as we're using 212 * squashfs_read_table here to read the superblock (including the value 213 * of bytes_used) we need to set it to an initial sensible dummy value 214 */ 215 msblk->bytes_used = sizeof(*sblk); 216 sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk)); 217 218 if (IS_ERR(sblk)) { 219 errorf(fc, "unable to read squashfs_super_block"); 220 err = PTR_ERR(sblk); 221 sblk = NULL; 222 goto failed_mount; 223 } 224 225 err = -EINVAL; 226 227 /* Check it is a SQUASHFS superblock */ 228 sb->s_magic = le32_to_cpu(sblk->s_magic); 229 if (sb->s_magic != SQUASHFS_MAGIC) { 230 if (!(fc->sb_flags & SB_SILENT)) 231 errorf(fc, "Can't find a SQUASHFS superblock on %pg", 232 sb->s_bdev); 233 goto failed_mount; 234 } 235 236 if (opts->thread_num == 0) { 237 msblk->max_thread_num = msblk->thread_ops->max_decompressors(); 238 } else { 239 msblk->max_thread_num = opts->thread_num; 240 } 241 242 /* Check the MAJOR & MINOR versions and lookup compression type */ 243 msblk->decompressor = supported_squashfs_filesystem( 244 fc, 245 le16_to_cpu(sblk->s_major), 246 le16_to_cpu(sblk->s_minor), 247 le16_to_cpu(sblk->compression)); 248 if (msblk->decompressor == NULL) 249 goto failed_mount; 250 251 /* Check the filesystem does not extend beyond the end of the 252 block device */ 253 msblk->bytes_used = le64_to_cpu(sblk->bytes_used); 254 if (msblk->bytes_used < 0 || 255 msblk->bytes_used > bdev_nr_bytes(sb->s_bdev)) 256 goto failed_mount; 257 258 /* Check block size for sanity */ 259 msblk->block_size = le32_to_cpu(sblk->block_size); 260 if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE) 261 goto insanity; 262 263 /* 264 * Check the system page size is not larger than the filesystem 265 * block size (by default 128K). This is currently not supported. 266 */ 267 if (PAGE_SIZE > msblk->block_size) { 268 errorf(fc, "Page size > filesystem block size (%d). This is " 269 "currently not supported!", msblk->block_size); 270 goto failed_mount; 271 } 272 273 /* Check block log for sanity */ 274 msblk->block_log = le16_to_cpu(sblk->block_log); 275 if (msblk->block_log > SQUASHFS_FILE_MAX_LOG) 276 goto failed_mount; 277 278 /* Check that block_size and block_log match */ 279 if (msblk->block_size != (1 << msblk->block_log)) 280 goto insanity; 281 282 /* Check the root inode for sanity */ 283 root_inode = le64_to_cpu(sblk->root_inode); 284 if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE) 285 goto insanity; 286 287 msblk->inode_table = le64_to_cpu(sblk->inode_table_start); 288 msblk->directory_table = le64_to_cpu(sblk->directory_table_start); 289 msblk->inodes = le32_to_cpu(sblk->inodes); 290 msblk->fragments = le32_to_cpu(sblk->fragments); 291 msblk->ids = le16_to_cpu(sblk->no_ids); 292 flags = le16_to_cpu(sblk->flags); 293 294 TRACE("Found valid superblock on %pg\n", sb->s_bdev); 295 TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags) 296 ? "un" : ""); 297 TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags) 298 ? "un" : ""); 299 TRACE("Filesystem size %lld bytes\n", msblk->bytes_used); 300 TRACE("Block size %d\n", msblk->block_size); 301 TRACE("Number of inodes %d\n", msblk->inodes); 302 TRACE("Number of fragments %d\n", msblk->fragments); 303 TRACE("Number of ids %d\n", msblk->ids); 304 TRACE("sblk->inode_table_start %llx\n", msblk->inode_table); 305 TRACE("sblk->directory_table_start %llx\n", msblk->directory_table); 306 TRACE("sblk->fragment_table_start %llx\n", 307 (u64) le64_to_cpu(sblk->fragment_table_start)); 308 TRACE("sblk->id_table_start %llx\n", 309 (u64) le64_to_cpu(sblk->id_table_start)); 310 311 sb->s_maxbytes = MAX_LFS_FILESIZE; 312 sb->s_time_min = 0; 313 sb->s_time_max = U32_MAX; 314 sb->s_flags |= SB_RDONLY; 315 sb->s_op = &squashfs_super_ops; 316 317 err = -ENOMEM; 318 319 msblk->block_cache = squashfs_cache_init("metadata", 320 SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE); 321 if (msblk->block_cache == NULL) 322 goto failed_mount; 323 324 /* Allocate read_page block */ 325 msblk->read_page = squashfs_cache_init("data", 326 msblk->max_thread_num, msblk->block_size); 327 if (msblk->read_page == NULL) { 328 errorf(fc, "Failed to allocate read_page block"); 329 goto failed_mount; 330 } 331 332 if (msblk->devblksize == PAGE_SIZE) { 333 struct inode *cache = new_inode(sb); 334 335 if (cache == NULL) 336 goto failed_mount; 337 338 set_nlink(cache, 1); 339 cache->i_size = OFFSET_MAX; 340 mapping_set_gfp_mask(cache->i_mapping, GFP_NOFS); 341 342 msblk->cache_mapping = cache->i_mapping; 343 } 344 345 msblk->stream = squashfs_decompressor_setup(sb, flags); 346 if (IS_ERR(msblk->stream)) { 347 err = PTR_ERR(msblk->stream); 348 msblk->stream = NULL; 349 goto insanity; 350 } 351 352 /* Handle xattrs */ 353 sb->s_xattr = squashfs_xattr_handlers; 354 xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start); 355 if (xattr_id_table_start == SQUASHFS_INVALID_BLK) { 356 next_table = msblk->bytes_used; 357 goto allocate_id_index_table; 358 } 359 360 /* Allocate and read xattr id lookup table */ 361 msblk->xattr_id_table = squashfs_read_xattr_id_table(sb, 362 xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids); 363 if (IS_ERR(msblk->xattr_id_table)) { 364 errorf(fc, "unable to read xattr id index table"); 365 err = PTR_ERR(msblk->xattr_id_table); 366 msblk->xattr_id_table = NULL; 367 if (err != -ENOTSUPP) 368 goto failed_mount; 369 } 370 next_table = msblk->xattr_table; 371 372 allocate_id_index_table: 373 /* Allocate and read id index table */ 374 msblk->id_table = squashfs_read_id_index_table(sb, 375 le64_to_cpu(sblk->id_table_start), next_table, msblk->ids); 376 if (IS_ERR(msblk->id_table)) { 377 errorf(fc, "unable to read id index table"); 378 err = PTR_ERR(msblk->id_table); 379 msblk->id_table = NULL; 380 goto failed_mount; 381 } 382 next_table = le64_to_cpu(msblk->id_table[0]); 383 384 /* Handle inode lookup table */ 385 lookup_table_start = le64_to_cpu(sblk->lookup_table_start); 386 if (lookup_table_start == SQUASHFS_INVALID_BLK) 387 goto handle_fragments; 388 389 /* Allocate and read inode lookup table */ 390 msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb, 391 lookup_table_start, next_table, msblk->inodes); 392 if (IS_ERR(msblk->inode_lookup_table)) { 393 errorf(fc, "unable to read inode lookup table"); 394 err = PTR_ERR(msblk->inode_lookup_table); 395 msblk->inode_lookup_table = NULL; 396 goto failed_mount; 397 } 398 next_table = le64_to_cpu(msblk->inode_lookup_table[0]); 399 400 sb->s_export_op = &squashfs_export_ops; 401 402 handle_fragments: 403 fragments = msblk->fragments; 404 if (fragments == 0) 405 goto check_directory_table; 406 407 msblk->fragment_cache = squashfs_cache_init("fragment", 408 SQUASHFS_CACHED_FRAGMENTS, msblk->block_size); 409 if (msblk->fragment_cache == NULL) { 410 err = -ENOMEM; 411 goto failed_mount; 412 } 413 414 /* Allocate and read fragment index table */ 415 msblk->fragment_index = squashfs_read_fragment_index_table(sb, 416 le64_to_cpu(sblk->fragment_table_start), next_table, fragments); 417 if (IS_ERR(msblk->fragment_index)) { 418 errorf(fc, "unable to read fragment index table"); 419 err = PTR_ERR(msblk->fragment_index); 420 msblk->fragment_index = NULL; 421 goto failed_mount; 422 } 423 next_table = le64_to_cpu(msblk->fragment_index[0]); 424 425 check_directory_table: 426 /* Sanity check directory_table */ 427 if (msblk->directory_table > next_table) { 428 err = -EINVAL; 429 goto insanity; 430 } 431 432 /* Sanity check inode_table */ 433 if (msblk->inode_table >= msblk->directory_table) { 434 err = -EINVAL; 435 goto insanity; 436 } 437 438 /* allocate root */ 439 root = new_inode(sb); 440 if (!root) { 441 err = -ENOMEM; 442 goto failed_mount; 443 } 444 445 err = squashfs_read_inode(root, root_inode); 446 if (err) { 447 make_bad_inode(root); 448 iput(root); 449 goto failed_mount; 450 } 451 insert_inode_hash(root); 452 453 sb->s_root = d_make_root(root); 454 if (sb->s_root == NULL) { 455 ERROR("Root inode create failed\n"); 456 err = -ENOMEM; 457 goto failed_mount; 458 } 459 460 TRACE("Leaving squashfs_fill_super\n"); 461 kfree(sblk); 462 return 0; 463 464 insanity: 465 errorf(fc, "squashfs image failed sanity check"); 466 failed_mount: 467 squashfs_cache_delete(msblk->block_cache); 468 squashfs_cache_delete(msblk->fragment_cache); 469 squashfs_cache_delete(msblk->read_page); 470 if (msblk->cache_mapping) 471 iput(msblk->cache_mapping->host); 472 msblk->thread_ops->destroy(msblk); 473 kfree(msblk->inode_lookup_table); 474 kfree(msblk->fragment_index); 475 kfree(msblk->id_table); 476 kfree(msblk->xattr_id_table); 477 kfree(sb->s_fs_info); 478 sb->s_fs_info = NULL; 479 kfree(sblk); 480 return err; 481 } 482 483 static int squashfs_get_tree(struct fs_context *fc) 484 { 485 return get_tree_bdev(fc, squashfs_fill_super); 486 } 487 488 static int squashfs_reconfigure(struct fs_context *fc) 489 { 490 struct super_block *sb = fc->root->d_sb; 491 struct squashfs_sb_info *msblk = sb->s_fs_info; 492 struct squashfs_mount_opts *opts = fc->fs_private; 493 494 sync_filesystem(fc->root->d_sb); 495 fc->sb_flags |= SB_RDONLY; 496 497 msblk->panic_on_errors = (opts->errors == Opt_errors_panic); 498 499 return 0; 500 } 501 502 static void squashfs_free_fs_context(struct fs_context *fc) 503 { 504 kfree(fc->fs_private); 505 } 506 507 static const struct fs_context_operations squashfs_context_ops = { 508 .get_tree = squashfs_get_tree, 509 .free = squashfs_free_fs_context, 510 .parse_param = squashfs_parse_param, 511 .reconfigure = squashfs_reconfigure, 512 }; 513 514 static int squashfs_show_options(struct seq_file *s, struct dentry *root) 515 { 516 struct super_block *sb = root->d_sb; 517 struct squashfs_sb_info *msblk = sb->s_fs_info; 518 519 if (msblk->panic_on_errors) 520 seq_puts(s, ",errors=panic"); 521 else 522 seq_puts(s, ",errors=continue"); 523 524 #ifdef CONFIG_SQUASHFS_CHOICE_DECOMP_BY_MOUNT 525 if (msblk->thread_ops == &squashfs_decompressor_single) { 526 seq_puts(s, ",threads=single"); 527 return 0; 528 } 529 if (msblk->thread_ops == &squashfs_decompressor_percpu) { 530 seq_puts(s, ",threads=percpu"); 531 return 0; 532 } 533 #endif 534 #ifdef CONFIG_SQUASHFS_MOUNT_DECOMP_THREADS 535 seq_printf(s, ",threads=%d", msblk->max_thread_num); 536 #endif 537 return 0; 538 } 539 540 static int squashfs_init_fs_context(struct fs_context *fc) 541 { 542 struct squashfs_mount_opts *opts; 543 544 opts = kzalloc(sizeof(*opts), GFP_KERNEL); 545 if (!opts) 546 return -ENOMEM; 547 548 #ifdef CONFIG_SQUASHFS_DECOMP_SINGLE 549 opts->thread_ops = &squashfs_decompressor_single; 550 #elif defined(CONFIG_SQUASHFS_DECOMP_MULTI) 551 opts->thread_ops = &squashfs_decompressor_multi; 552 #elif defined(CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU) 553 opts->thread_ops = &squashfs_decompressor_percpu; 554 #else 555 #error "fail: unknown squashfs decompression thread mode?" 556 #endif 557 opts->thread_num = 0; 558 fc->fs_private = opts; 559 fc->ops = &squashfs_context_ops; 560 return 0; 561 } 562 563 static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf) 564 { 565 struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info; 566 u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev); 567 568 TRACE("Entered squashfs_statfs\n"); 569 570 buf->f_type = SQUASHFS_MAGIC; 571 buf->f_bsize = msblk->block_size; 572 buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1; 573 buf->f_bfree = buf->f_bavail = 0; 574 buf->f_files = msblk->inodes; 575 buf->f_ffree = 0; 576 buf->f_namelen = SQUASHFS_NAME_LEN; 577 buf->f_fsid = u64_to_fsid(id); 578 579 return 0; 580 } 581 582 583 static void squashfs_put_super(struct super_block *sb) 584 { 585 if (sb->s_fs_info) { 586 struct squashfs_sb_info *sbi = sb->s_fs_info; 587 squashfs_cache_delete(sbi->block_cache); 588 squashfs_cache_delete(sbi->fragment_cache); 589 squashfs_cache_delete(sbi->read_page); 590 if (sbi->cache_mapping) 591 iput(sbi->cache_mapping->host); 592 sbi->thread_ops->destroy(sbi); 593 kfree(sbi->id_table); 594 kfree(sbi->fragment_index); 595 kfree(sbi->meta_index); 596 kfree(sbi->inode_lookup_table); 597 kfree(sbi->xattr_id_table); 598 kfree(sb->s_fs_info); 599 sb->s_fs_info = NULL; 600 } 601 } 602 603 static struct kmem_cache *squashfs_inode_cachep; 604 605 606 static void init_once(void *foo) 607 { 608 struct squashfs_inode_info *ei = foo; 609 610 inode_init_once(&ei->vfs_inode); 611 } 612 613 614 static int __init init_inodecache(void) 615 { 616 squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache", 617 sizeof(struct squashfs_inode_info), 0, 618 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT, 619 init_once); 620 621 return squashfs_inode_cachep ? 0 : -ENOMEM; 622 } 623 624 625 static void destroy_inodecache(void) 626 { 627 /* 628 * Make sure all delayed rcu free inodes are flushed before we 629 * destroy cache. 630 */ 631 rcu_barrier(); 632 kmem_cache_destroy(squashfs_inode_cachep); 633 } 634 635 636 static int __init init_squashfs_fs(void) 637 { 638 int err = init_inodecache(); 639 640 if (err) 641 return err; 642 643 err = register_filesystem(&squashfs_fs_type); 644 if (err) { 645 destroy_inodecache(); 646 return err; 647 } 648 649 pr_info("version 4.0 (2009/01/31) Phillip Lougher\n"); 650 651 return 0; 652 } 653 654 655 static void __exit exit_squashfs_fs(void) 656 { 657 unregister_filesystem(&squashfs_fs_type); 658 destroy_inodecache(); 659 } 660 661 662 static struct inode *squashfs_alloc_inode(struct super_block *sb) 663 { 664 struct squashfs_inode_info *ei = 665 alloc_inode_sb(sb, squashfs_inode_cachep, GFP_KERNEL); 666 667 return ei ? &ei->vfs_inode : NULL; 668 } 669 670 671 static void squashfs_free_inode(struct inode *inode) 672 { 673 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode)); 674 } 675 676 static struct file_system_type squashfs_fs_type = { 677 .owner = THIS_MODULE, 678 .name = "squashfs", 679 .init_fs_context = squashfs_init_fs_context, 680 .parameters = squashfs_fs_parameters, 681 .kill_sb = kill_block_super, 682 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP, 683 }; 684 MODULE_ALIAS_FS("squashfs"); 685 686 static const struct super_operations squashfs_super_ops = { 687 .alloc_inode = squashfs_alloc_inode, 688 .free_inode = squashfs_free_inode, 689 .statfs = squashfs_statfs, 690 .put_super = squashfs_put_super, 691 .show_options = squashfs_show_options, 692 }; 693 694 module_init(init_squashfs_fs); 695 module_exit(exit_squashfs_fs); 696 MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem"); 697 MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>"); 698 MODULE_LICENSE("GPL"); 699