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1/*
2 * Squashfs - a compressed read only filesystem for Linux
3 *
4 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
5 * Phillip Lougher <phillip@squashfs.org.uk>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2,
10 * or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 *
21 * super.c
22 */
23
24/*
25 * This file implements code to read the superblock, read and initialise
26 * in-memory structures at mount time, and all the VFS glue code to register
27 * the filesystem.
28 */
29
30#include <linux/fs.h>
31#include <linux/vfs.h>
32#include <linux/slab.h>
33#include <linux/mutex.h>
34#include <linux/pagemap.h>
35#include <linux/init.h>
36#include <linux/module.h>
37#include <linux/magic.h>
38#include <linux/xattr.h>
39
40#include "squashfs_fs.h"
41#include "squashfs_fs_sb.h"
42#include "squashfs_fs_i.h"
43#include "squashfs.h"
44#include "decompressor.h"
45#include "xattr.h"
46
47static struct file_system_type squashfs_fs_type;
48static const struct super_operations squashfs_super_ops;
49
50static const struct squashfs_decompressor *supported_squashfs_filesystem(short
51 major, short minor, short id)
52{
53 const struct squashfs_decompressor *decompressor;
54
55 if (major < SQUASHFS_MAJOR) {
56 ERROR("Major/Minor mismatch, older Squashfs %d.%d "
57 "filesystems are unsupported\n", major, minor);
58 return NULL;
59 } else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
60 ERROR("Major/Minor mismatch, trying to mount newer "
61 "%d.%d filesystem\n", major, minor);
62 ERROR("Please update your kernel\n");
63 return NULL;
64 }
65
66 decompressor = squashfs_lookup_decompressor(id);
67 if (!decompressor->supported) {
68 ERROR("Filesystem uses \"%s\" compression. This is not "
69 "supported\n", decompressor->name);
70 return NULL;
71 }
72
73 return decompressor;
74}
75
76
77static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
78{
79 struct squashfs_sb_info *msblk;
80 struct squashfs_super_block *sblk = NULL;
81 char b[BDEVNAME_SIZE];
82 struct inode *root;
83 long long root_inode;
84 unsigned short flags;
85 unsigned int fragments;
86 u64 lookup_table_start, xattr_id_table_start, next_table;
87 int err;
88
89 TRACE("Entered squashfs_fill_superblock\n");
90
91 sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
92 if (sb->s_fs_info == NULL) {
93 ERROR("Failed to allocate squashfs_sb_info\n");
94 return -ENOMEM;
95 }
96 msblk = sb->s_fs_info;
97
98 msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
99 msblk->devblksize_log2 = ffz(~msblk->devblksize);
100
101 mutex_init(&msblk->read_data_mutex);
102 mutex_init(&msblk->meta_index_mutex);
103
104 /*
105 * msblk->bytes_used is checked in squashfs_read_table to ensure reads
106 * are not beyond filesystem end. But as we're using
107 * squashfs_read_table here to read the superblock (including the value
108 * of bytes_used) we need to set it to an initial sensible dummy value
109 */
110 msblk->bytes_used = sizeof(*sblk);
111 sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
112
113 if (IS_ERR(sblk)) {
114 ERROR("unable to read squashfs_super_block\n");
115 err = PTR_ERR(sblk);
116 sblk = NULL;
117 goto failed_mount;
118 }
119
120 err = -EINVAL;
121
122 /* Check it is a SQUASHFS superblock */
123 sb->s_magic = le32_to_cpu(sblk->s_magic);
124 if (sb->s_magic != SQUASHFS_MAGIC) {
125 if (!silent)
126 ERROR("Can't find a SQUASHFS superblock on %s\n",
127 bdevname(sb->s_bdev, b));
128 goto failed_mount;
129 }
130
131 /* Check the MAJOR & MINOR versions and lookup compression type */
132 msblk->decompressor = supported_squashfs_filesystem(
133 le16_to_cpu(sblk->s_major),
134 le16_to_cpu(sblk->s_minor),
135 le16_to_cpu(sblk->compression));
136 if (msblk->decompressor == NULL)
137 goto failed_mount;
138
139 /* Check the filesystem does not extend beyond the end of the
140 block device */
141 msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
142 if (msblk->bytes_used < 0 || msblk->bytes_used >
143 i_size_read(sb->s_bdev->bd_inode))
144 goto failed_mount;
145
146 /* Check block size for sanity */
147 msblk->block_size = le32_to_cpu(sblk->block_size);
148 if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
149 goto failed_mount;
150
151 /*
152 * Check the system page size is not larger than the filesystem
153 * block size (by default 128K). This is currently not supported.
154 */
155 if (PAGE_CACHE_SIZE > msblk->block_size) {
156 ERROR("Page size > filesystem block size (%d). This is "
157 "currently not supported!\n", msblk->block_size);
158 goto failed_mount;
159 }
160
161 msblk->block_log = le16_to_cpu(sblk->block_log);
162 if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
163 goto failed_mount;
164
165 /* Check the root inode for sanity */
166 root_inode = le64_to_cpu(sblk->root_inode);
167 if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
168 goto failed_mount;
169
170 msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
171 msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
172 msblk->inodes = le32_to_cpu(sblk->inodes);
173 flags = le16_to_cpu(sblk->flags);
174
175 TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
176 TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
177 ? "un" : "");
178 TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
179 ? "un" : "");
180 TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
181 TRACE("Block size %d\n", msblk->block_size);
182 TRACE("Number of inodes %d\n", msblk->inodes);
183 TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
184 TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
185 TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
186 TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
187 TRACE("sblk->fragment_table_start %llx\n",
188 (u64) le64_to_cpu(sblk->fragment_table_start));
189 TRACE("sblk->id_table_start %llx\n",
190 (u64) le64_to_cpu(sblk->id_table_start));
191
192 sb->s_maxbytes = MAX_LFS_FILESIZE;
193 sb->s_flags |= MS_RDONLY;
194 sb->s_op = &squashfs_super_ops;
195
196 err = -ENOMEM;
197
198 msblk->block_cache = squashfs_cache_init("metadata",
199 SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
200 if (msblk->block_cache == NULL)
201 goto failed_mount;
202
203 /* Allocate read_page block */
204 msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
205 if (msblk->read_page == NULL) {
206 ERROR("Failed to allocate read_page block\n");
207 goto failed_mount;
208 }
209
210 msblk->stream = squashfs_decompressor_init(sb, flags);
211 if (IS_ERR(msblk->stream)) {
212 err = PTR_ERR(msblk->stream);
213 msblk->stream = NULL;
214 goto failed_mount;
215 }
216
217 /* Handle xattrs */
218 sb->s_xattr = squashfs_xattr_handlers;
219 xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
220 if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
221 next_table = msblk->bytes_used;
222 goto allocate_id_index_table;
223 }
224
225 /* Allocate and read xattr id lookup table */
226 msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
227 xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
228 if (IS_ERR(msblk->xattr_id_table)) {
229 ERROR("unable to read xattr id index table\n");
230 err = PTR_ERR(msblk->xattr_id_table);
231 msblk->xattr_id_table = NULL;
232 if (err != -ENOTSUPP)
233 goto failed_mount;
234 }
235 next_table = msblk->xattr_table;
236
237allocate_id_index_table:
238 /* Allocate and read id index table */
239 msblk->id_table = squashfs_read_id_index_table(sb,
240 le64_to_cpu(sblk->id_table_start), next_table,
241 le16_to_cpu(sblk->no_ids));
242 if (IS_ERR(msblk->id_table)) {
243 ERROR("unable to read id index table\n");
244 err = PTR_ERR(msblk->id_table);
245 msblk->id_table = NULL;
246 goto failed_mount;
247 }
248 next_table = le64_to_cpu(msblk->id_table[0]);
249
250 /* Handle inode lookup table */
251 lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
252 if (lookup_table_start == SQUASHFS_INVALID_BLK)
253 goto handle_fragments;
254
255 /* Allocate and read inode lookup table */
256 msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
257 lookup_table_start, next_table, msblk->inodes);
258 if (IS_ERR(msblk->inode_lookup_table)) {
259 ERROR("unable to read inode lookup table\n");
260 err = PTR_ERR(msblk->inode_lookup_table);
261 msblk->inode_lookup_table = NULL;
262 goto failed_mount;
263 }
264 next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
265
266 sb->s_export_op = &squashfs_export_ops;
267
268handle_fragments:
269 fragments = le32_to_cpu(sblk->fragments);
270 if (fragments == 0)
271 goto check_directory_table;
272
273 msblk->fragment_cache = squashfs_cache_init("fragment",
274 SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
275 if (msblk->fragment_cache == NULL) {
276 err = -ENOMEM;
277 goto failed_mount;
278 }
279
280 /* Allocate and read fragment index table */
281 msblk->fragment_index = squashfs_read_fragment_index_table(sb,
282 le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
283 if (IS_ERR(msblk->fragment_index)) {
284 ERROR("unable to read fragment index table\n");
285 err = PTR_ERR(msblk->fragment_index);
286 msblk->fragment_index = NULL;
287 goto failed_mount;
288 }
289 next_table = le64_to_cpu(msblk->fragment_index[0]);
290
291check_directory_table:
292 /* Sanity check directory_table */
293 if (msblk->directory_table >= next_table) {
294 err = -EINVAL;
295 goto failed_mount;
296 }
297
298 /* Sanity check inode_table */
299 if (msblk->inode_table >= msblk->directory_table) {
300 err = -EINVAL;
301 goto failed_mount;
302 }
303
304 /* allocate root */
305 root = new_inode(sb);
306 if (!root) {
307 err = -ENOMEM;
308 goto failed_mount;
309 }
310
311 err = squashfs_read_inode(root, root_inode);
312 if (err) {
313 make_bad_inode(root);
314 iput(root);
315 goto failed_mount;
316 }
317 insert_inode_hash(root);
318
319 sb->s_root = d_alloc_root(root);
320 if (sb->s_root == NULL) {
321 ERROR("Root inode create failed\n");
322 err = -ENOMEM;
323 iput(root);
324 goto failed_mount;
325 }
326
327 TRACE("Leaving squashfs_fill_super\n");
328 kfree(sblk);
329 return 0;
330
331failed_mount:
332 squashfs_cache_delete(msblk->block_cache);
333 squashfs_cache_delete(msblk->fragment_cache);
334 squashfs_cache_delete(msblk->read_page);
335 squashfs_decompressor_free(msblk, msblk->stream);
336 kfree(msblk->inode_lookup_table);
337 kfree(msblk->fragment_index);
338 kfree(msblk->id_table);
339 kfree(msblk->xattr_id_table);
340 kfree(sb->s_fs_info);
341 sb->s_fs_info = NULL;
342 kfree(sblk);
343 return err;
344}
345
346
347static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
348{
349 struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
350 u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
351
352 TRACE("Entered squashfs_statfs\n");
353
354 buf->f_type = SQUASHFS_MAGIC;
355 buf->f_bsize = msblk->block_size;
356 buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
357 buf->f_bfree = buf->f_bavail = 0;
358 buf->f_files = msblk->inodes;
359 buf->f_ffree = 0;
360 buf->f_namelen = SQUASHFS_NAME_LEN;
361 buf->f_fsid.val[0] = (u32)id;
362 buf->f_fsid.val[1] = (u32)(id >> 32);
363
364 return 0;
365}
366
367
368static int squashfs_remount(struct super_block *sb, int *flags, char *data)
369{
370 *flags |= MS_RDONLY;
371 return 0;
372}
373
374
375static void squashfs_put_super(struct super_block *sb)
376{
377 if (sb->s_fs_info) {
378 struct squashfs_sb_info *sbi = sb->s_fs_info;
379 squashfs_cache_delete(sbi->block_cache);
380 squashfs_cache_delete(sbi->fragment_cache);
381 squashfs_cache_delete(sbi->read_page);
382 squashfs_decompressor_free(sbi, sbi->stream);
383 kfree(sbi->id_table);
384 kfree(sbi->fragment_index);
385 kfree(sbi->meta_index);
386 kfree(sbi->inode_lookup_table);
387 kfree(sbi->xattr_id_table);
388 kfree(sb->s_fs_info);
389 sb->s_fs_info = NULL;
390 }
391}
392
393
394static struct dentry *squashfs_mount(struct file_system_type *fs_type,
395 int flags, const char *dev_name, void *data)
396{
397 return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
398}
399
400
401static struct kmem_cache *squashfs_inode_cachep;
402
403
404static void init_once(void *foo)
405{
406 struct squashfs_inode_info *ei = foo;
407
408 inode_init_once(&ei->vfs_inode);
409}
410
411
412static int __init init_inodecache(void)
413{
414 squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
415 sizeof(struct squashfs_inode_info), 0,
416 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, init_once);
417
418 return squashfs_inode_cachep ? 0 : -ENOMEM;
419}
420
421
422static void destroy_inodecache(void)
423{
424 kmem_cache_destroy(squashfs_inode_cachep);
425}
426
427
428static int __init init_squashfs_fs(void)
429{
430 int err = init_inodecache();
431
432 if (err)
433 return err;
434
435 err = register_filesystem(&squashfs_fs_type);
436 if (err) {
437 destroy_inodecache();
438 return err;
439 }
440
441 printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
442 "Phillip Lougher\n");
443
444 return 0;
445}
446
447
448static void __exit exit_squashfs_fs(void)
449{
450 unregister_filesystem(&squashfs_fs_type);
451 destroy_inodecache();
452}
453
454
455static struct inode *squashfs_alloc_inode(struct super_block *sb)
456{
457 struct squashfs_inode_info *ei =
458 kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
459
460 return ei ? &ei->vfs_inode : NULL;
461}
462
463
464static void squashfs_i_callback(struct rcu_head *head)
465{
466 struct inode *inode = container_of(head, struct inode, i_rcu);
467 INIT_LIST_HEAD(&inode->i_dentry);
468 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
469}
470
471static void squashfs_destroy_inode(struct inode *inode)
472{
473 call_rcu(&inode->i_rcu, squashfs_i_callback);
474}
475
476
477static struct file_system_type squashfs_fs_type = {
478 .owner = THIS_MODULE,
479 .name = "squashfs",
480 .mount = squashfs_mount,
481 .kill_sb = kill_block_super,
482 .fs_flags = FS_REQUIRES_DEV
483};
484
485static const struct super_operations squashfs_super_ops = {
486 .alloc_inode = squashfs_alloc_inode,
487 .destroy_inode = squashfs_destroy_inode,
488 .statfs = squashfs_statfs,
489 .put_super = squashfs_put_super,
490 .remount_fs = squashfs_remount
491};
492
493module_init(init_squashfs_fs);
494module_exit(exit_squashfs_fs);
495MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
496MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
497MODULE_LICENSE("GPL");
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
40static struct file_system_type squashfs_fs_type;
41static const struct super_operations squashfs_super_ops;
42
43enum Opt_errors {
44 Opt_errors_continue,
45 Opt_errors_panic,
46};
47
48enum squashfs_param {
49 Opt_errors,
50 Opt_threads,
51};
52
53struct squashfs_mount_opts {
54 enum Opt_errors errors;
55 const struct squashfs_decompressor_thread_ops *thread_ops;
56 int thread_num;
57};
58
59static const struct constant_table squashfs_param_errors[] = {
60 {"continue", Opt_errors_continue },
61 {"panic", Opt_errors_panic },
62 {}
63};
64
65static 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
72static 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
91static 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
118static 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
127static 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
152static 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
180static 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
372allocate_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
402handle_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
425check_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
464insanity:
465 errorf(fc, "squashfs image failed sanity check");
466failed_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
483static int squashfs_get_tree(struct fs_context *fc)
484{
485 return get_tree_bdev(fc, squashfs_fill_super);
486}
487
488static 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
502static void squashfs_free_fs_context(struct fs_context *fc)
503{
504 kfree(fc->fs_private);
505}
506
507static 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
514static 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
540static 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
563static 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
583static 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
603static struct kmem_cache *squashfs_inode_cachep;
604
605
606static void init_once(void *foo)
607{
608 struct squashfs_inode_info *ei = foo;
609
610 inode_init_once(&ei->vfs_inode);
611}
612
613
614static 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
625static 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
636static 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
655static void __exit exit_squashfs_fs(void)
656{
657 unregister_filesystem(&squashfs_fs_type);
658 destroy_inodecache();
659}
660
661
662static 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
671static void squashfs_free_inode(struct inode *inode)
672{
673 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
674}
675
676static 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};
684MODULE_ALIAS_FS("squashfs");
685
686static 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
694module_init(init_squashfs_fs);
695module_exit(exit_squashfs_fs);
696MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
697MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
698MODULE_LICENSE("GPL");