fs/squashfs/super.c

   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         msblk->block_cache = squashfs_cache_init("metadata",
 318                         SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
 319         if (IS_ERR(msblk->block_cache)) {
 320                 err = PTR_ERR(msblk->block_cache);
 321                 goto failed_mount;
 322         }
 323
 324         /* Allocate read_page block */
 325         msblk->read_page = squashfs_cache_init("data",
 326                 SQUASHFS_READ_PAGES, msblk->block_size);
 327         if (IS_ERR(msblk->read_page)) {
 328                 errorf(fc, "Failed to allocate read_page block");
 329                 err = PTR_ERR(msblk->read_page);
 330                 goto failed_mount;
 331         }
 332
 333         if (msblk->devblksize == PAGE_SIZE) {
 334                 struct inode *cache = new_inode(sb);
 335
 336                 if (cache == NULL) {
 337                         err = -ENOMEM;
 338                         goto failed_mount;
 339                 }
 340
 341                 set_nlink(cache, 1);
 342                 cache->i_size = OFFSET_MAX;
 343                 mapping_set_gfp_mask(cache->i_mapping, GFP_NOFS);
 344
 345                 msblk->cache_mapping = cache->i_mapping;
 346         }
 347
 348         msblk->stream = squashfs_decompressor_setup(sb, flags);
 349         if (IS_ERR(msblk->stream)) {
 350                 err = PTR_ERR(msblk->stream);
 351                 msblk->stream = NULL;
 352                 goto insanity;
 353         }
 354
 355         /* Handle xattrs */
 356         sb->s_xattr = squashfs_xattr_handlers;
 357         xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
 358         if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
 359                 next_table = msblk->bytes_used;
 360                 goto allocate_id_index_table;
 361         }
 362
 363         /* Allocate and read xattr id lookup table */
 364         msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
 365                 xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
 366         if (IS_ERR(msblk->xattr_id_table)) {
 367                 errorf(fc, "unable to read xattr id index table");
 368                 err = PTR_ERR(msblk->xattr_id_table);
 369                 msblk->xattr_id_table = NULL;
 370                 if (err != -ENOTSUPP)
 371                         goto failed_mount;
 372         }
 373         next_table = msblk->xattr_table;
 374
 375 allocate_id_index_table:
 376         /* Allocate and read id index table */
 377         msblk->id_table = squashfs_read_id_index_table(sb,
 378                 le64_to_cpu(sblk->id_table_start), next_table, msblk->ids);
 379         if (IS_ERR(msblk->id_table)) {
 380                 errorf(fc, "unable to read id index table");
 381                 err = PTR_ERR(msblk->id_table);
 382                 msblk->id_table = NULL;
 383                 goto failed_mount;
 384         }
 385         next_table = le64_to_cpu(msblk->id_table[0]);
 386
 387         /* Handle inode lookup table */
 388         lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
 389         if (lookup_table_start == SQUASHFS_INVALID_BLK)
 390                 goto handle_fragments;
 391
 392         /* Allocate and read inode lookup table */
 393         msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
 394                 lookup_table_start, next_table, msblk->inodes);
 395         if (IS_ERR(msblk->inode_lookup_table)) {
 396                 errorf(fc, "unable to read inode lookup table");
 397                 err = PTR_ERR(msblk->inode_lookup_table);
 398                 msblk->inode_lookup_table = NULL;
 399                 goto failed_mount;
 400         }
 401         next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
 402
 403         sb->s_export_op = &squashfs_export_ops;
 404
 405 handle_fragments:
 406         fragments = msblk->fragments;
 407         if (fragments == 0)
 408                 goto check_directory_table;
 409
 410         msblk->fragment_cache = squashfs_cache_init("fragment",
 411                 min(SQUASHFS_CACHED_FRAGMENTS, fragments), msblk->block_size);
 412         if (IS_ERR(msblk->fragment_cache)) {
 413                 err = PTR_ERR(msblk->fragment_cache);
 414                 goto failed_mount;
 415         }
 416
 417         /* Allocate and read fragment index table */
 418         msblk->fragment_index = squashfs_read_fragment_index_table(sb,
 419                 le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
 420         if (IS_ERR(msblk->fragment_index)) {
 421                 errorf(fc, "unable to read fragment index table");
 422                 err = PTR_ERR(msblk->fragment_index);
 423                 msblk->fragment_index = NULL;
 424                 goto failed_mount;
 425         }
 426         next_table = le64_to_cpu(msblk->fragment_index[0]);
 427
 428 check_directory_table:
 429         /* Sanity check directory_table */
 430         if (msblk->directory_table > next_table) {
 431                 err = -EINVAL;
 432                 goto insanity;
 433         }
 434
 435         /* Sanity check inode_table */
 436         if (msblk->inode_table >= msblk->directory_table) {
 437                 err = -EINVAL;
 438                 goto insanity;
 439         }
 440
 441         /* allocate root */
 442         root = new_inode(sb);
 443         if (!root) {
 444                 err = -ENOMEM;
 445                 goto failed_mount;
 446         }
 447
 448         err = squashfs_read_inode(root, root_inode);
 449         if (err) {
 450                 make_bad_inode(root);
 451                 iput(root);
 452                 goto failed_mount;
 453         }
 454         insert_inode_hash(root);
 455
 456         sb->s_root = d_make_root(root);
 457         if (sb->s_root == NULL) {
 458                 ERROR("Root inode create failed\n");
 459                 err = -ENOMEM;
 460                 goto failed_mount;
 461         }
 462
 463         TRACE("Leaving squashfs_fill_super\n");
 464         kfree(sblk);
 465         return 0;
 466
 467 insanity:
 468         errorf(fc, "squashfs image failed sanity check");
 469 failed_mount:
 470         squashfs_cache_delete(msblk->block_cache);
 471         squashfs_cache_delete(msblk->fragment_cache);
 472         squashfs_cache_delete(msblk->read_page);
 473         if (msblk->cache_mapping)
 474                 iput(msblk->cache_mapping->host);
 475         msblk->thread_ops->destroy(msblk);
 476         kfree(msblk->inode_lookup_table);
 477         kfree(msblk->fragment_index);
 478         kfree(msblk->id_table);
 479         kfree(msblk->xattr_id_table);
 480         kfree(sb->s_fs_info);
 481         sb->s_fs_info = NULL;
 482         kfree(sblk);
 483         return err;
 484 }
 485
 486 static int squashfs_get_tree(struct fs_context *fc)
 487 {
 488         return get_tree_bdev(fc, squashfs_fill_super);
 489 }
 490
 491 static int squashfs_reconfigure(struct fs_context *fc)
 492 {
 493         struct super_block *sb = fc->root->d_sb;
 494         struct squashfs_sb_info *msblk = sb->s_fs_info;
 495         struct squashfs_mount_opts *opts = fc->fs_private;
 496
 497         sync_filesystem(fc->root->d_sb);
 498         fc->sb_flags |= SB_RDONLY;
 499
 500         msblk->panic_on_errors = (opts->errors == Opt_errors_panic);
 501
 502         return 0;
 503 }
 504
 505 static void squashfs_free_fs_context(struct fs_context *fc)
 506 {
 507         kfree(fc->fs_private);
 508 }
 509
 510 static const struct fs_context_operations squashfs_context_ops = {
 511         .get_tree       = squashfs_get_tree,
 512         .free           = squashfs_free_fs_context,
 513         .parse_param    = squashfs_parse_param,
 514         .reconfigure    = squashfs_reconfigure,
 515 };
 516
 517 static int squashfs_show_options(struct seq_file *s, struct dentry *root)
 518 {
 519         struct super_block *sb = root->d_sb;
 520         struct squashfs_sb_info *msblk = sb->s_fs_info;
 521
 522         if (msblk->panic_on_errors)
 523                 seq_puts(s, ",errors=panic");
 524         else
 525                 seq_puts(s, ",errors=continue");
 526
 527 #ifdef CONFIG_SQUASHFS_CHOICE_DECOMP_BY_MOUNT
 528         if (msblk->thread_ops == &squashfs_decompressor_single) {
 529                 seq_puts(s, ",threads=single");
 530                 return 0;
 531         }
 532         if (msblk->thread_ops == &squashfs_decompressor_percpu) {
 533                 seq_puts(s, ",threads=percpu");
 534                 return 0;
 535         }
 536 #endif
 537 #ifdef CONFIG_SQUASHFS_MOUNT_DECOMP_THREADS
 538         seq_printf(s, ",threads=%d", msblk->max_thread_num);
 539 #endif
 540         return 0;
 541 }
 542
 543 static int squashfs_init_fs_context(struct fs_context *fc)
 544 {
 545         struct squashfs_mount_opts *opts;
 546
 547         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 548         if (!opts)
 549                 return -ENOMEM;
 550
 551 #ifdef CONFIG_SQUASHFS_DECOMP_SINGLE
 552         opts->thread_ops = &squashfs_decompressor_single;
 553 #elif defined(CONFIG_SQUASHFS_DECOMP_MULTI)
 554         opts->thread_ops = &squashfs_decompressor_multi;
 555 #elif defined(CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU)
 556         opts->thread_ops = &squashfs_decompressor_percpu;
 557 #else
 558 #error "fail: unknown squashfs decompression thread mode?"
 559 #endif
 560         opts->thread_num = 0;
 561         fc->fs_private = opts;
 562         fc->ops = &squashfs_context_ops;
 563         return 0;
 564 }
 565
 566 static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 567 {
 568         struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
 569         u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
 570
 571         TRACE("Entered squashfs_statfs\n");
 572
 573         buf->f_type = SQUASHFS_MAGIC;
 574         buf->f_bsize = msblk->block_size;
 575         buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
 576         buf->f_bfree = buf->f_bavail = 0;
 577         buf->f_files = msblk->inodes;
 578         buf->f_ffree = 0;
 579         buf->f_namelen = SQUASHFS_NAME_LEN;
 580         buf->f_fsid = u64_to_fsid(id);
 581
 582         return 0;
 583 }
 584
 585
 586 static void squashfs_put_super(struct super_block *sb)
 587 {
 588         if (sb->s_fs_info) {
 589                 struct squashfs_sb_info *sbi = sb->s_fs_info;
 590                 squashfs_cache_delete(sbi->block_cache);
 591                 squashfs_cache_delete(sbi->fragment_cache);
 592                 squashfs_cache_delete(sbi->read_page);
 593                 if (sbi->cache_mapping)
 594                         iput(sbi->cache_mapping->host);
 595                 sbi->thread_ops->destroy(sbi);
 596                 kfree(sbi->id_table);
 597                 kfree(sbi->fragment_index);
 598                 kfree(sbi->meta_index);
 599                 kfree(sbi->inode_lookup_table);
 600                 kfree(sbi->xattr_id_table);
 601                 kfree(sb->s_fs_info);
 602                 sb->s_fs_info = NULL;
 603         }
 604 }
 605
 606 static struct kmem_cache *squashfs_inode_cachep;
 607
 608
 609 static void init_once(void *foo)
 610 {
 611         struct squashfs_inode_info *ei = foo;
 612
 613         inode_init_once(&ei->vfs_inode);
 614 }
 615
 616
 617 static int __init init_inodecache(void)
 618 {
 619         squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
 620                 sizeof(struct squashfs_inode_info), 0,
 621                 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
 622                 init_once);
 623
 624         return squashfs_inode_cachep ? 0 : -ENOMEM;
 625 }
 626
 627
 628 static void destroy_inodecache(void)
 629 {
 630         /*
 631          * Make sure all delayed rcu free inodes are flushed before we
 632          * destroy cache.
 633          */
 634         rcu_barrier();
 635         kmem_cache_destroy(squashfs_inode_cachep);
 636 }
 637
 638
 639 static int __init init_squashfs_fs(void)
 640 {
 641         int err = init_inodecache();
 642
 643         if (err)
 644                 return err;
 645
 646         err = register_filesystem(&squashfs_fs_type);
 647         if (err) {
 648                 destroy_inodecache();
 649                 return err;
 650         }
 651
 652         pr_info("version 4.0 (2009/01/31) Phillip Lougher\n");
 653
 654         return 0;
 655 }
 656
 657
 658 static void __exit exit_squashfs_fs(void)
 659 {
 660         unregister_filesystem(&squashfs_fs_type);
 661         destroy_inodecache();
 662 }
 663
 664
 665 static struct inode *squashfs_alloc_inode(struct super_block *sb)
 666 {
 667         struct squashfs_inode_info *ei =
 668                 alloc_inode_sb(sb, squashfs_inode_cachep, GFP_KERNEL);
 669
 670         return ei ? &ei->vfs_inode : NULL;
 671 }
 672
 673
 674 static void squashfs_free_inode(struct inode *inode)
 675 {
 676         kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
 677 }
 678
 679 static struct file_system_type squashfs_fs_type = {
 680         .owner = THIS_MODULE,
 681         .name = "squashfs",
 682         .init_fs_context = squashfs_init_fs_context,
 683         .parameters = squashfs_fs_parameters,
 684         .kill_sb = kill_block_super,
 685         .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
 686 };
 687 MODULE_ALIAS_FS("squashfs");
 688
 689 static const struct super_operations squashfs_super_ops = {
 690         .alloc_inode = squashfs_alloc_inode,
 691         .free_inode = squashfs_free_inode,
 692         .statfs = squashfs_statfs,
 693         .put_super = squashfs_put_super,
 694         .show_options = squashfs_show_options,
 695 };
 696
 697 module_init(init_squashfs_fs);
 698 module_exit(exit_squashfs_fs);
 699 MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
 700 MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
 701 MODULE_LICENSE("GPL");