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
squashfs_parse_param_threads_str(const char * str,struct squashfs_mount_opts * opts)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
squashfs_parse_param_threads_num(const char * str,struct squashfs_mount_opts * opts)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
squashfs_parse_param_threads(const char * str,struct squashfs_mount_opts * opts)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
squashfs_parse_param(struct fs_context * fc,struct fs_parameter * param)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
supported_squashfs_filesystem(struct fs_context * fc,short major,short minor,short id)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
squashfs_fill_super(struct super_block * sb,struct fs_context * fc)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 if (!msblk->devblksize) {
206 errorf(fc, "squashfs: unable to set blocksize\n");
207 return -EINVAL;
208 }
209
210 msblk->devblksize_log2 = ffz(~msblk->devblksize);
211
212 mutex_init(&msblk->meta_index_mutex);
213
214 /*
215 * msblk->bytes_used is checked in squashfs_read_table to ensure reads
216 * are not beyond filesystem end. But as we're using
217 * squashfs_read_table here to read the superblock (including the value
218 * of bytes_used) we need to set it to an initial sensible dummy value
219 */
220 msblk->bytes_used = sizeof(*sblk);
221 sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
222
223 if (IS_ERR(sblk)) {
224 errorf(fc, "unable to read squashfs_super_block");
225 err = PTR_ERR(sblk);
226 sblk = NULL;
227 goto failed_mount;
228 }
229
230 err = -EINVAL;
231
232 /* Check it is a SQUASHFS superblock */
233 sb->s_magic = le32_to_cpu(sblk->s_magic);
234 if (sb->s_magic != SQUASHFS_MAGIC) {
235 if (!(fc->sb_flags & SB_SILENT))
236 errorf(fc, "Can't find a SQUASHFS superblock on %pg",
237 sb->s_bdev);
238 goto failed_mount;
239 }
240
241 if (opts->thread_num == 0) {
242 msblk->max_thread_num = msblk->thread_ops->max_decompressors();
243 } else {
244 msblk->max_thread_num = opts->thread_num;
245 }
246
247 /* Check the MAJOR & MINOR versions and lookup compression type */
248 msblk->decompressor = supported_squashfs_filesystem(
249 fc,
250 le16_to_cpu(sblk->s_major),
251 le16_to_cpu(sblk->s_minor),
252 le16_to_cpu(sblk->compression));
253 if (msblk->decompressor == NULL)
254 goto failed_mount;
255
256 /* Check the filesystem does not extend beyond the end of the
257 block device */
258 msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
259 if (msblk->bytes_used < 0 ||
260 msblk->bytes_used > bdev_nr_bytes(sb->s_bdev))
261 goto failed_mount;
262
263 /* Check block size for sanity */
264 msblk->block_size = le32_to_cpu(sblk->block_size);
265 if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
266 goto insanity;
267
268 /*
269 * Check the system page size is not larger than the filesystem
270 * block size (by default 128K). This is currently not supported.
271 */
272 if (PAGE_SIZE > msblk->block_size) {
273 errorf(fc, "Page size > filesystem block size (%d). This is "
274 "currently not supported!", msblk->block_size);
275 goto failed_mount;
276 }
277
278 /* Check block log for sanity */
279 msblk->block_log = le16_to_cpu(sblk->block_log);
280 if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
281 goto failed_mount;
282
283 /* Check that block_size and block_log match */
284 if (msblk->block_size != (1 << msblk->block_log))
285 goto insanity;
286
287 /* Check the root inode for sanity */
288 root_inode = le64_to_cpu(sblk->root_inode);
289 if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
290 goto insanity;
291
292 msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
293 msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
294 msblk->inodes = le32_to_cpu(sblk->inodes);
295 msblk->fragments = le32_to_cpu(sblk->fragments);
296 msblk->ids = le16_to_cpu(sblk->no_ids);
297 flags = le16_to_cpu(sblk->flags);
298
299 TRACE("Found valid superblock on %pg\n", sb->s_bdev);
300 TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
301 ? "un" : "");
302 TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
303 ? "un" : "");
304 TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
305 TRACE("Block size %d\n", msblk->block_size);
306 TRACE("Number of inodes %d\n", msblk->inodes);
307 TRACE("Number of fragments %d\n", msblk->fragments);
308 TRACE("Number of ids %d\n", msblk->ids);
309 TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
310 TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
311 TRACE("sblk->fragment_table_start %llx\n",
312 (u64) le64_to_cpu(sblk->fragment_table_start));
313 TRACE("sblk->id_table_start %llx\n",
314 (u64) le64_to_cpu(sblk->id_table_start));
315
316 sb->s_maxbytes = MAX_LFS_FILESIZE;
317 sb->s_time_min = 0;
318 sb->s_time_max = U32_MAX;
319 sb->s_flags |= SB_RDONLY;
320 sb->s_op = &squashfs_super_ops;
321
322 err = -ENOMEM;
323
324 msblk->block_cache = squashfs_cache_init("metadata",
325 SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
326 if (msblk->block_cache == NULL)
327 goto failed_mount;
328
329 /* Allocate read_page block */
330 msblk->read_page = squashfs_cache_init("data",
331 msblk->max_thread_num, msblk->block_size);
332 if (msblk->read_page == NULL) {
333 errorf(fc, "Failed to allocate read_page block");
334 goto failed_mount;
335 }
336
337 if (msblk->devblksize == PAGE_SIZE) {
338 struct inode *cache = new_inode(sb);
339
340 if (cache == NULL)
341 goto failed_mount;
342
343 set_nlink(cache, 1);
344 cache->i_size = OFFSET_MAX;
345 mapping_set_gfp_mask(cache->i_mapping, GFP_NOFS);
346
347 msblk->cache_mapping = cache->i_mapping;
348 }
349
350 msblk->stream = squashfs_decompressor_setup(sb, flags);
351 if (IS_ERR(msblk->stream)) {
352 err = PTR_ERR(msblk->stream);
353 msblk->stream = NULL;
354 goto insanity;
355 }
356
357 /* Handle xattrs */
358 sb->s_xattr = squashfs_xattr_handlers;
359 xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
360 if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
361 next_table = msblk->bytes_used;
362 goto allocate_id_index_table;
363 }
364
365 /* Allocate and read xattr id lookup table */
366 msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
367 xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
368 if (IS_ERR(msblk->xattr_id_table)) {
369 errorf(fc, "unable to read xattr id index table");
370 err = PTR_ERR(msblk->xattr_id_table);
371 msblk->xattr_id_table = NULL;
372 if (err != -ENOTSUPP)
373 goto failed_mount;
374 }
375 next_table = msblk->xattr_table;
376
377 allocate_id_index_table:
378 /* Allocate and read id index table */
379 msblk->id_table = squashfs_read_id_index_table(sb,
380 le64_to_cpu(sblk->id_table_start), next_table, msblk->ids);
381 if (IS_ERR(msblk->id_table)) {
382 errorf(fc, "unable to read id index table");
383 err = PTR_ERR(msblk->id_table);
384 msblk->id_table = NULL;
385 goto failed_mount;
386 }
387 next_table = le64_to_cpu(msblk->id_table[0]);
388
389 /* Handle inode lookup table */
390 lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
391 if (lookup_table_start == SQUASHFS_INVALID_BLK)
392 goto handle_fragments;
393
394 /* Allocate and read inode lookup table */
395 msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
396 lookup_table_start, next_table, msblk->inodes);
397 if (IS_ERR(msblk->inode_lookup_table)) {
398 errorf(fc, "unable to read inode lookup table");
399 err = PTR_ERR(msblk->inode_lookup_table);
400 msblk->inode_lookup_table = NULL;
401 goto failed_mount;
402 }
403 next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
404
405 sb->s_export_op = &squashfs_export_ops;
406
407 handle_fragments:
408 fragments = msblk->fragments;
409 if (fragments == 0)
410 goto check_directory_table;
411
412 msblk->fragment_cache = squashfs_cache_init("fragment",
413 SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
414 if (msblk->fragment_cache == NULL) {
415 err = -ENOMEM;
416 goto failed_mount;
417 }
418
419 /* Allocate and read fragment index table */
420 msblk->fragment_index = squashfs_read_fragment_index_table(sb,
421 le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
422 if (IS_ERR(msblk->fragment_index)) {
423 errorf(fc, "unable to read fragment index table");
424 err = PTR_ERR(msblk->fragment_index);
425 msblk->fragment_index = NULL;
426 goto failed_mount;
427 }
428 next_table = le64_to_cpu(msblk->fragment_index[0]);
429
430 check_directory_table:
431 /* Sanity check directory_table */
432 if (msblk->directory_table > next_table) {
433 err = -EINVAL;
434 goto insanity;
435 }
436
437 /* Sanity check inode_table */
438 if (msblk->inode_table >= msblk->directory_table) {
439 err = -EINVAL;
440 goto insanity;
441 }
442
443 /* allocate root */
444 root = new_inode(sb);
445 if (!root) {
446 err = -ENOMEM;
447 goto failed_mount;
448 }
449
450 err = squashfs_read_inode(root, root_inode);
451 if (err) {
452 make_bad_inode(root);
453 iput(root);
454 goto failed_mount;
455 }
456 insert_inode_hash(root);
457
458 sb->s_root = d_make_root(root);
459 if (sb->s_root == NULL) {
460 ERROR("Root inode create failed\n");
461 err = -ENOMEM;
462 goto failed_mount;
463 }
464
465 TRACE("Leaving squashfs_fill_super\n");
466 kfree(sblk);
467 return 0;
468
469 insanity:
470 errorf(fc, "squashfs image failed sanity check");
471 failed_mount:
472 squashfs_cache_delete(msblk->block_cache);
473 squashfs_cache_delete(msblk->fragment_cache);
474 squashfs_cache_delete(msblk->read_page);
475 if (msblk->cache_mapping)
476 iput(msblk->cache_mapping->host);
477 msblk->thread_ops->destroy(msblk);
478 kfree(msblk->inode_lookup_table);
479 kfree(msblk->fragment_index);
480 kfree(msblk->id_table);
481 kfree(msblk->xattr_id_table);
482 kfree(sb->s_fs_info);
483 sb->s_fs_info = NULL;
484 kfree(sblk);
485 return err;
486 }
487
squashfs_get_tree(struct fs_context * fc)488 static int squashfs_get_tree(struct fs_context *fc)
489 {
490 return get_tree_bdev(fc, squashfs_fill_super);
491 }
492
squashfs_reconfigure(struct fs_context * fc)493 static int squashfs_reconfigure(struct fs_context *fc)
494 {
495 struct super_block *sb = fc->root->d_sb;
496 struct squashfs_sb_info *msblk = sb->s_fs_info;
497 struct squashfs_mount_opts *opts = fc->fs_private;
498
499 sync_filesystem(fc->root->d_sb);
500 fc->sb_flags |= SB_RDONLY;
501
502 msblk->panic_on_errors = (opts->errors == Opt_errors_panic);
503
504 return 0;
505 }
506
squashfs_free_fs_context(struct fs_context * fc)507 static void squashfs_free_fs_context(struct fs_context *fc)
508 {
509 kfree(fc->fs_private);
510 }
511
512 static const struct fs_context_operations squashfs_context_ops = {
513 .get_tree = squashfs_get_tree,
514 .free = squashfs_free_fs_context,
515 .parse_param = squashfs_parse_param,
516 .reconfigure = squashfs_reconfigure,
517 };
518
squashfs_show_options(struct seq_file * s,struct dentry * root)519 static int squashfs_show_options(struct seq_file *s, struct dentry *root)
520 {
521 struct super_block *sb = root->d_sb;
522 struct squashfs_sb_info *msblk = sb->s_fs_info;
523
524 if (msblk->panic_on_errors)
525 seq_puts(s, ",errors=panic");
526 else
527 seq_puts(s, ",errors=continue");
528
529 #ifdef CONFIG_SQUASHFS_CHOICE_DECOMP_BY_MOUNT
530 if (msblk->thread_ops == &squashfs_decompressor_single) {
531 seq_puts(s, ",threads=single");
532 return 0;
533 }
534 if (msblk->thread_ops == &squashfs_decompressor_percpu) {
535 seq_puts(s, ",threads=percpu");
536 return 0;
537 }
538 #endif
539 #ifdef CONFIG_SQUASHFS_MOUNT_DECOMP_THREADS
540 seq_printf(s, ",threads=%d", msblk->max_thread_num);
541 #endif
542 return 0;
543 }
544
squashfs_init_fs_context(struct fs_context * fc)545 static int squashfs_init_fs_context(struct fs_context *fc)
546 {
547 struct squashfs_mount_opts *opts;
548
549 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
550 if (!opts)
551 return -ENOMEM;
552
553 #ifdef CONFIG_SQUASHFS_DECOMP_SINGLE
554 opts->thread_ops = &squashfs_decompressor_single;
555 #elif defined(CONFIG_SQUASHFS_DECOMP_MULTI)
556 opts->thread_ops = &squashfs_decompressor_multi;
557 #elif defined(CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU)
558 opts->thread_ops = &squashfs_decompressor_percpu;
559 #else
560 #error "fail: unknown squashfs decompression thread mode?"
561 #endif
562 opts->thread_num = 0;
563 fc->fs_private = opts;
564 fc->ops = &squashfs_context_ops;
565 return 0;
566 }
567
squashfs_statfs(struct dentry * dentry,struct kstatfs * buf)568 static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
569 {
570 struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
571 u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
572
573 TRACE("Entered squashfs_statfs\n");
574
575 buf->f_type = SQUASHFS_MAGIC;
576 buf->f_bsize = msblk->block_size;
577 buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
578 buf->f_bfree = buf->f_bavail = 0;
579 buf->f_files = msblk->inodes;
580 buf->f_ffree = 0;
581 buf->f_namelen = SQUASHFS_NAME_LEN;
582 buf->f_fsid = u64_to_fsid(id);
583
584 return 0;
585 }
586
587
squashfs_put_super(struct super_block * sb)588 static void squashfs_put_super(struct super_block *sb)
589 {
590 if (sb->s_fs_info) {
591 struct squashfs_sb_info *sbi = sb->s_fs_info;
592 squashfs_cache_delete(sbi->block_cache);
593 squashfs_cache_delete(sbi->fragment_cache);
594 squashfs_cache_delete(sbi->read_page);
595 if (sbi->cache_mapping)
596 iput(sbi->cache_mapping->host);
597 sbi->thread_ops->destroy(sbi);
598 kfree(sbi->id_table);
599 kfree(sbi->fragment_index);
600 kfree(sbi->meta_index);
601 kfree(sbi->inode_lookup_table);
602 kfree(sbi->xattr_id_table);
603 kfree(sb->s_fs_info);
604 sb->s_fs_info = NULL;
605 }
606 }
607
608 static struct kmem_cache *squashfs_inode_cachep;
609
610
init_once(void * foo)611 static void init_once(void *foo)
612 {
613 struct squashfs_inode_info *ei = foo;
614
615 inode_init_once(&ei->vfs_inode);
616 }
617
618
init_inodecache(void)619 static int __init init_inodecache(void)
620 {
621 squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
622 sizeof(struct squashfs_inode_info), 0,
623 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
624 init_once);
625
626 return squashfs_inode_cachep ? 0 : -ENOMEM;
627 }
628
629
destroy_inodecache(void)630 static void destroy_inodecache(void)
631 {
632 /*
633 * Make sure all delayed rcu free inodes are flushed before we
634 * destroy cache.
635 */
636 rcu_barrier();
637 kmem_cache_destroy(squashfs_inode_cachep);
638 }
639
640
init_squashfs_fs(void)641 static int __init init_squashfs_fs(void)
642 {
643 int err = init_inodecache();
644
645 if (err)
646 return err;
647
648 err = register_filesystem(&squashfs_fs_type);
649 if (err) {
650 destroy_inodecache();
651 return err;
652 }
653
654 pr_info("version 4.0 (2009/01/31) Phillip Lougher\n");
655
656 return 0;
657 }
658
659
exit_squashfs_fs(void)660 static void __exit exit_squashfs_fs(void)
661 {
662 unregister_filesystem(&squashfs_fs_type);
663 destroy_inodecache();
664 }
665
666
squashfs_alloc_inode(struct super_block * sb)667 static struct inode *squashfs_alloc_inode(struct super_block *sb)
668 {
669 struct squashfs_inode_info *ei =
670 alloc_inode_sb(sb, squashfs_inode_cachep, GFP_KERNEL);
671
672 return ei ? &ei->vfs_inode : NULL;
673 }
674
675
squashfs_free_inode(struct inode * inode)676 static void squashfs_free_inode(struct inode *inode)
677 {
678 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
679 }
680
681 static struct file_system_type squashfs_fs_type = {
682 .owner = THIS_MODULE,
683 .name = "squashfs",
684 .init_fs_context = squashfs_init_fs_context,
685 .parameters = squashfs_fs_parameters,
686 .kill_sb = kill_block_super,
687 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
688 };
689 MODULE_ALIAS_FS("squashfs");
690
691 static const struct super_operations squashfs_super_ops = {
692 .alloc_inode = squashfs_alloc_inode,
693 .free_inode = squashfs_free_inode,
694 .statfs = squashfs_statfs,
695 .put_super = squashfs_put_super,
696 .show_options = squashfs_show_options,
697 };
698
699 module_init(init_squashfs_fs);
700 module_exit(exit_squashfs_fs);
701 MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
702 MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
703 MODULE_LICENSE("GPL");
704