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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
31
32#include <linux/fs.h>
33#include <linux/vfs.h>
34#include <linux/slab.h>
35#include <linux/mutex.h>
36#include <linux/pagemap.h>
37#include <linux/init.h>
38#include <linux/module.h>
39#include <linux/magic.h>
40#include <linux/xattr.h>
41
42#include "squashfs_fs.h"
43#include "squashfs_fs_sb.h"
44#include "squashfs_fs_i.h"
45#include "squashfs.h"
46#include "decompressor.h"
47#include "xattr.h"
48
49static struct file_system_type squashfs_fs_type;
50static const struct super_operations squashfs_super_ops;
51
52static const struct squashfs_decompressor *supported_squashfs_filesystem(short
53 major, short minor, short id)
54{
55 const struct squashfs_decompressor *decompressor;
56
57 if (major < SQUASHFS_MAJOR) {
58 ERROR("Major/Minor mismatch, older Squashfs %d.%d "
59 "filesystems are unsupported\n", major, minor);
60 return NULL;
61 } else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
62 ERROR("Major/Minor mismatch, trying to mount newer "
63 "%d.%d filesystem\n", major, minor);
64 ERROR("Please update your kernel\n");
65 return NULL;
66 }
67
68 decompressor = squashfs_lookup_decompressor(id);
69 if (!decompressor->supported) {
70 ERROR("Filesystem uses \"%s\" compression. This is not "
71 "supported\n", decompressor->name);
72 return NULL;
73 }
74
75 return decompressor;
76}
77
78
79static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
80{
81 struct squashfs_sb_info *msblk;
82 struct squashfs_super_block *sblk = NULL;
83 struct inode *root;
84 long long root_inode;
85 unsigned short flags;
86 unsigned int fragments;
87 u64 lookup_table_start, xattr_id_table_start, next_table;
88 int err;
89
90 TRACE("Entered squashfs_fill_superblock\n");
91
92 sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
93 if (sb->s_fs_info == NULL) {
94 ERROR("Failed to allocate squashfs_sb_info\n");
95 return -ENOMEM;
96 }
97 msblk = sb->s_fs_info;
98
99 msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);
100 msblk->devblksize_log2 = ffz(~msblk->devblksize);
101
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 %pg\n",
127 sb->s_bdev);
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_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 /* Check block log for sanity */
162 msblk->block_log = le16_to_cpu(sblk->block_log);
163 if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
164 goto failed_mount;
165
166 /* Check that block_size and block_log match */
167 if (msblk->block_size != (1 << msblk->block_log))
168 goto failed_mount;
169
170 /* Check the root inode for sanity */
171 root_inode = le64_to_cpu(sblk->root_inode);
172 if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
173 goto failed_mount;
174
175 msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
176 msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
177 msblk->inodes = le32_to_cpu(sblk->inodes);
178 flags = le16_to_cpu(sblk->flags);
179
180 TRACE("Found valid superblock on %pg\n", sb->s_bdev);
181 TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
182 ? "un" : "");
183 TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
184 ? "un" : "");
185 TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
186 TRACE("Block size %d\n", msblk->block_size);
187 TRACE("Number of inodes %d\n", msblk->inodes);
188 TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
189 TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
190 TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
191 TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
192 TRACE("sblk->fragment_table_start %llx\n",
193 (u64) le64_to_cpu(sblk->fragment_table_start));
194 TRACE("sblk->id_table_start %llx\n",
195 (u64) le64_to_cpu(sblk->id_table_start));
196
197 sb->s_maxbytes = MAX_LFS_FILESIZE;
198 sb->s_flags |= MS_RDONLY;
199 sb->s_op = &squashfs_super_ops;
200
201 err = -ENOMEM;
202
203 msblk->block_cache = squashfs_cache_init("metadata",
204 SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
205 if (msblk->block_cache == NULL)
206 goto failed_mount;
207
208 /* Allocate read_page block */
209 msblk->read_page = squashfs_cache_init("data",
210 squashfs_max_decompressors(), msblk->block_size);
211 if (msblk->read_page == NULL) {
212 ERROR("Failed to allocate read_page block\n");
213 goto failed_mount;
214 }
215
216 msblk->stream = squashfs_decompressor_setup(sb, flags);
217 if (IS_ERR(msblk->stream)) {
218 err = PTR_ERR(msblk->stream);
219 msblk->stream = NULL;
220 goto failed_mount;
221 }
222
223 /* Handle xattrs */
224 sb->s_xattr = squashfs_xattr_handlers;
225 xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
226 if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
227 next_table = msblk->bytes_used;
228 goto allocate_id_index_table;
229 }
230
231 /* Allocate and read xattr id lookup table */
232 msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
233 xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
234 if (IS_ERR(msblk->xattr_id_table)) {
235 ERROR("unable to read xattr id index table\n");
236 err = PTR_ERR(msblk->xattr_id_table);
237 msblk->xattr_id_table = NULL;
238 if (err != -ENOTSUPP)
239 goto failed_mount;
240 }
241 next_table = msblk->xattr_table;
242
243allocate_id_index_table:
244 /* Allocate and read id index table */
245 msblk->id_table = squashfs_read_id_index_table(sb,
246 le64_to_cpu(sblk->id_table_start), next_table,
247 le16_to_cpu(sblk->no_ids));
248 if (IS_ERR(msblk->id_table)) {
249 ERROR("unable to read id index table\n");
250 err = PTR_ERR(msblk->id_table);
251 msblk->id_table = NULL;
252 goto failed_mount;
253 }
254 next_table = le64_to_cpu(msblk->id_table[0]);
255
256 /* Handle inode lookup table */
257 lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
258 if (lookup_table_start == SQUASHFS_INVALID_BLK)
259 goto handle_fragments;
260
261 /* Allocate and read inode lookup table */
262 msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
263 lookup_table_start, next_table, msblk->inodes);
264 if (IS_ERR(msblk->inode_lookup_table)) {
265 ERROR("unable to read inode lookup table\n");
266 err = PTR_ERR(msblk->inode_lookup_table);
267 msblk->inode_lookup_table = NULL;
268 goto failed_mount;
269 }
270 next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
271
272 sb->s_export_op = &squashfs_export_ops;
273
274handle_fragments:
275 fragments = le32_to_cpu(sblk->fragments);
276 if (fragments == 0)
277 goto check_directory_table;
278
279 msblk->fragment_cache = squashfs_cache_init("fragment",
280 SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
281 if (msblk->fragment_cache == NULL) {
282 err = -ENOMEM;
283 goto failed_mount;
284 }
285
286 /* Allocate and read fragment index table */
287 msblk->fragment_index = squashfs_read_fragment_index_table(sb,
288 le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
289 if (IS_ERR(msblk->fragment_index)) {
290 ERROR("unable to read fragment index table\n");
291 err = PTR_ERR(msblk->fragment_index);
292 msblk->fragment_index = NULL;
293 goto failed_mount;
294 }
295 next_table = le64_to_cpu(msblk->fragment_index[0]);
296
297check_directory_table:
298 /* Sanity check directory_table */
299 if (msblk->directory_table > next_table) {
300 err = -EINVAL;
301 goto failed_mount;
302 }
303
304 /* Sanity check inode_table */
305 if (msblk->inode_table >= msblk->directory_table) {
306 err = -EINVAL;
307 goto failed_mount;
308 }
309
310 /* allocate root */
311 root = new_inode(sb);
312 if (!root) {
313 err = -ENOMEM;
314 goto failed_mount;
315 }
316
317 err = squashfs_read_inode(root, root_inode);
318 if (err) {
319 make_bad_inode(root);
320 iput(root);
321 goto failed_mount;
322 }
323 insert_inode_hash(root);
324
325 sb->s_root = d_make_root(root);
326 if (sb->s_root == NULL) {
327 ERROR("Root inode create failed\n");
328 err = -ENOMEM;
329 goto failed_mount;
330 }
331
332 TRACE("Leaving squashfs_fill_super\n");
333 kfree(sblk);
334 return 0;
335
336failed_mount:
337 squashfs_cache_delete(msblk->block_cache);
338 squashfs_cache_delete(msblk->fragment_cache);
339 squashfs_cache_delete(msblk->read_page);
340 squashfs_decompressor_destroy(msblk);
341 kfree(msblk->inode_lookup_table);
342 kfree(msblk->fragment_index);
343 kfree(msblk->id_table);
344 kfree(msblk->xattr_id_table);
345 kfree(sb->s_fs_info);
346 sb->s_fs_info = NULL;
347 kfree(sblk);
348 return err;
349}
350
351
352static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
353{
354 struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
355 u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
356
357 TRACE("Entered squashfs_statfs\n");
358
359 buf->f_type = SQUASHFS_MAGIC;
360 buf->f_bsize = msblk->block_size;
361 buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
362 buf->f_bfree = buf->f_bavail = 0;
363 buf->f_files = msblk->inodes;
364 buf->f_ffree = 0;
365 buf->f_namelen = SQUASHFS_NAME_LEN;
366 buf->f_fsid.val[0] = (u32)id;
367 buf->f_fsid.val[1] = (u32)(id >> 32);
368
369 return 0;
370}
371
372
373static int squashfs_remount(struct super_block *sb, int *flags, char *data)
374{
375 sync_filesystem(sb);
376 *flags |= MS_RDONLY;
377 return 0;
378}
379
380
381static void squashfs_put_super(struct super_block *sb)
382{
383 if (sb->s_fs_info) {
384 struct squashfs_sb_info *sbi = sb->s_fs_info;
385 squashfs_cache_delete(sbi->block_cache);
386 squashfs_cache_delete(sbi->fragment_cache);
387 squashfs_cache_delete(sbi->read_page);
388 squashfs_decompressor_destroy(sbi);
389 kfree(sbi->id_table);
390 kfree(sbi->fragment_index);
391 kfree(sbi->meta_index);
392 kfree(sbi->inode_lookup_table);
393 kfree(sbi->xattr_id_table);
394 kfree(sb->s_fs_info);
395 sb->s_fs_info = NULL;
396 }
397}
398
399
400static struct dentry *squashfs_mount(struct file_system_type *fs_type,
401 int flags, const char *dev_name, void *data)
402{
403 return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
404}
405
406
407static struct kmem_cache *squashfs_inode_cachep;
408
409
410static void init_once(void *foo)
411{
412 struct squashfs_inode_info *ei = foo;
413
414 inode_init_once(&ei->vfs_inode);
415}
416
417
418static int __init init_inodecache(void)
419{
420 squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
421 sizeof(struct squashfs_inode_info), 0,
422 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
423 init_once);
424
425 return squashfs_inode_cachep ? 0 : -ENOMEM;
426}
427
428
429static void destroy_inodecache(void)
430{
431 /*
432 * Make sure all delayed rcu free inodes are flushed before we
433 * destroy cache.
434 */
435 rcu_barrier();
436 kmem_cache_destroy(squashfs_inode_cachep);
437}
438
439
440static int __init init_squashfs_fs(void)
441{
442 int err = init_inodecache();
443
444 if (err)
445 return err;
446
447 err = register_filesystem(&squashfs_fs_type);
448 if (err) {
449 destroy_inodecache();
450 return err;
451 }
452
453 pr_info("version 4.0 (2009/01/31) Phillip Lougher\n");
454
455 return 0;
456}
457
458
459static void __exit exit_squashfs_fs(void)
460{
461 unregister_filesystem(&squashfs_fs_type);
462 destroy_inodecache();
463}
464
465
466static struct inode *squashfs_alloc_inode(struct super_block *sb)
467{
468 struct squashfs_inode_info *ei =
469 kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
470
471 return ei ? &ei->vfs_inode : NULL;
472}
473
474
475static void squashfs_i_callback(struct rcu_head *head)
476{
477 struct inode *inode = container_of(head, struct inode, i_rcu);
478 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
479}
480
481static void squashfs_destroy_inode(struct inode *inode)
482{
483 call_rcu(&inode->i_rcu, squashfs_i_callback);
484}
485
486
487static struct file_system_type squashfs_fs_type = {
488 .owner = THIS_MODULE,
489 .name = "squashfs",
490 .mount = squashfs_mount,
491 .kill_sb = kill_block_super,
492 .fs_flags = FS_REQUIRES_DEV
493};
494MODULE_ALIAS_FS("squashfs");
495
496static const struct super_operations squashfs_super_ops = {
497 .alloc_inode = squashfs_alloc_inode,
498 .destroy_inode = squashfs_destroy_inode,
499 .statfs = squashfs_statfs,
500 .put_super = squashfs_put_super,
501 .remount_fs = squashfs_remount
502};
503
504module_init(init_squashfs_fs);
505module_exit(exit_squashfs_fs);
506MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
507MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
508MODULE_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/fs.h>
20#include <linux/fs_context.h>
21#include <linux/vfs.h>
22#include <linux/slab.h>
23#include <linux/mutex.h>
24#include <linux/pagemap.h>
25#include <linux/init.h>
26#include <linux/module.h>
27#include <linux/magic.h>
28#include <linux/xattr.h>
29
30#include "squashfs_fs.h"
31#include "squashfs_fs_sb.h"
32#include "squashfs_fs_i.h"
33#include "squashfs.h"
34#include "decompressor.h"
35#include "xattr.h"
36
37static struct file_system_type squashfs_fs_type;
38static const struct super_operations squashfs_super_ops;
39
40static const struct squashfs_decompressor *supported_squashfs_filesystem(
41 struct fs_context *fc,
42 short major, short minor, short id)
43{
44 const struct squashfs_decompressor *decompressor;
45
46 if (major < SQUASHFS_MAJOR) {
47 errorf(fc, "Major/Minor mismatch, older Squashfs %d.%d "
48 "filesystems are unsupported", major, minor);
49 return NULL;
50 } else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
51 errorf(fc, "Major/Minor mismatch, trying to mount newer "
52 "%d.%d filesystem", major, minor);
53 errorf(fc, "Please update your kernel");
54 return NULL;
55 }
56
57 decompressor = squashfs_lookup_decompressor(id);
58 if (!decompressor->supported) {
59 errorf(fc, "Filesystem uses \"%s\" compression. This is not supported",
60 decompressor->name);
61 return NULL;
62 }
63
64 return decompressor;
65}
66
67
68static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
69{
70 struct squashfs_sb_info *msblk;
71 struct squashfs_super_block *sblk = NULL;
72 struct inode *root;
73 long long root_inode;
74 unsigned short flags;
75 unsigned int fragments;
76 u64 lookup_table_start, xattr_id_table_start, next_table;
77 int err;
78
79 TRACE("Entered squashfs_fill_superblock\n");
80
81 sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
82 if (sb->s_fs_info == NULL) {
83 ERROR("Failed to allocate squashfs_sb_info\n");
84 return -ENOMEM;
85 }
86 msblk = sb->s_fs_info;
87
88 msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);
89 msblk->devblksize_log2 = ffz(~msblk->devblksize);
90
91 mutex_init(&msblk->meta_index_mutex);
92
93 /*
94 * msblk->bytes_used is checked in squashfs_read_table to ensure reads
95 * are not beyond filesystem end. But as we're using
96 * squashfs_read_table here to read the superblock (including the value
97 * of bytes_used) we need to set it to an initial sensible dummy value
98 */
99 msblk->bytes_used = sizeof(*sblk);
100 sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
101
102 if (IS_ERR(sblk)) {
103 errorf(fc, "unable to read squashfs_super_block");
104 err = PTR_ERR(sblk);
105 sblk = NULL;
106 goto failed_mount;
107 }
108
109 err = -EINVAL;
110
111 /* Check it is a SQUASHFS superblock */
112 sb->s_magic = le32_to_cpu(sblk->s_magic);
113 if (sb->s_magic != SQUASHFS_MAGIC) {
114 if (!(fc->sb_flags & SB_SILENT))
115 errorf(fc, "Can't find a SQUASHFS superblock on %pg",
116 sb->s_bdev);
117 goto failed_mount;
118 }
119
120 /* Check the MAJOR & MINOR versions and lookup compression type */
121 msblk->decompressor = supported_squashfs_filesystem(
122 fc,
123 le16_to_cpu(sblk->s_major),
124 le16_to_cpu(sblk->s_minor),
125 le16_to_cpu(sblk->compression));
126 if (msblk->decompressor == NULL)
127 goto failed_mount;
128
129 /* Check the filesystem does not extend beyond the end of the
130 block device */
131 msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
132 if (msblk->bytes_used < 0 || msblk->bytes_used >
133 i_size_read(sb->s_bdev->bd_inode))
134 goto failed_mount;
135
136 /* Check block size for sanity */
137 msblk->block_size = le32_to_cpu(sblk->block_size);
138 if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
139 goto insanity;
140
141 /*
142 * Check the system page size is not larger than the filesystem
143 * block size (by default 128K). This is currently not supported.
144 */
145 if (PAGE_SIZE > msblk->block_size) {
146 errorf(fc, "Page size > filesystem block size (%d). This is "
147 "currently not supported!", msblk->block_size);
148 goto failed_mount;
149 }
150
151 /* Check block log for sanity */
152 msblk->block_log = le16_to_cpu(sblk->block_log);
153 if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
154 goto failed_mount;
155
156 /* Check that block_size and block_log match */
157 if (msblk->block_size != (1 << msblk->block_log))
158 goto insanity;
159
160 /* Check the root inode for sanity */
161 root_inode = le64_to_cpu(sblk->root_inode);
162 if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
163 goto insanity;
164
165 msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
166 msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
167 msblk->inodes = le32_to_cpu(sblk->inodes);
168 msblk->fragments = le32_to_cpu(sblk->fragments);
169 flags = le16_to_cpu(sblk->flags);
170
171 TRACE("Found valid superblock on %pg\n", sb->s_bdev);
172 TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
173 ? "un" : "");
174 TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
175 ? "un" : "");
176 TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
177 TRACE("Block size %d\n", msblk->block_size);
178 TRACE("Number of inodes %d\n", msblk->inodes);
179 TRACE("Number of fragments %d\n", msblk->fragments);
180 TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
181 TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
182 TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
183 TRACE("sblk->fragment_table_start %llx\n",
184 (u64) le64_to_cpu(sblk->fragment_table_start));
185 TRACE("sblk->id_table_start %llx\n",
186 (u64) le64_to_cpu(sblk->id_table_start));
187
188 sb->s_maxbytes = MAX_LFS_FILESIZE;
189 sb->s_time_min = 0;
190 sb->s_time_max = U32_MAX;
191 sb->s_flags |= SB_RDONLY;
192 sb->s_op = &squashfs_super_ops;
193
194 err = -ENOMEM;
195
196 msblk->block_cache = squashfs_cache_init("metadata",
197 SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
198 if (msblk->block_cache == NULL)
199 goto failed_mount;
200
201 /* Allocate read_page block */
202 msblk->read_page = squashfs_cache_init("data",
203 squashfs_max_decompressors(), msblk->block_size);
204 if (msblk->read_page == NULL) {
205 errorf(fc, "Failed to allocate read_page block");
206 goto failed_mount;
207 }
208
209 msblk->stream = squashfs_decompressor_setup(sb, flags);
210 if (IS_ERR(msblk->stream)) {
211 err = PTR_ERR(msblk->stream);
212 msblk->stream = NULL;
213 goto insanity;
214 }
215
216 /* Handle xattrs */
217 sb->s_xattr = squashfs_xattr_handlers;
218 xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
219 if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
220 next_table = msblk->bytes_used;
221 goto allocate_id_index_table;
222 }
223
224 /* Allocate and read xattr id lookup table */
225 msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
226 xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
227 if (IS_ERR(msblk->xattr_id_table)) {
228 errorf(fc, "unable to read xattr id index table");
229 err = PTR_ERR(msblk->xattr_id_table);
230 msblk->xattr_id_table = NULL;
231 if (err != -ENOTSUPP)
232 goto failed_mount;
233 }
234 next_table = msblk->xattr_table;
235
236allocate_id_index_table:
237 /* Allocate and read id index table */
238 msblk->id_table = squashfs_read_id_index_table(sb,
239 le64_to_cpu(sblk->id_table_start), next_table,
240 le16_to_cpu(sblk->no_ids));
241 if (IS_ERR(msblk->id_table)) {
242 errorf(fc, "unable to read id index table");
243 err = PTR_ERR(msblk->id_table);
244 msblk->id_table = NULL;
245 goto failed_mount;
246 }
247 next_table = le64_to_cpu(msblk->id_table[0]);
248
249 /* Handle inode lookup table */
250 lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
251 if (lookup_table_start == SQUASHFS_INVALID_BLK)
252 goto handle_fragments;
253
254 /* Allocate and read inode lookup table */
255 msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
256 lookup_table_start, next_table, msblk->inodes);
257 if (IS_ERR(msblk->inode_lookup_table)) {
258 errorf(fc, "unable to read inode lookup table");
259 err = PTR_ERR(msblk->inode_lookup_table);
260 msblk->inode_lookup_table = NULL;
261 goto failed_mount;
262 }
263 next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
264
265 sb->s_export_op = &squashfs_export_ops;
266
267handle_fragments:
268 fragments = msblk->fragments;
269 if (fragments == 0)
270 goto check_directory_table;
271
272 msblk->fragment_cache = squashfs_cache_init("fragment",
273 SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
274 if (msblk->fragment_cache == NULL) {
275 err = -ENOMEM;
276 goto failed_mount;
277 }
278
279 /* Allocate and read fragment index table */
280 msblk->fragment_index = squashfs_read_fragment_index_table(sb,
281 le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
282 if (IS_ERR(msblk->fragment_index)) {
283 errorf(fc, "unable to read fragment index table");
284 err = PTR_ERR(msblk->fragment_index);
285 msblk->fragment_index = NULL;
286 goto failed_mount;
287 }
288 next_table = le64_to_cpu(msblk->fragment_index[0]);
289
290check_directory_table:
291 /* Sanity check directory_table */
292 if (msblk->directory_table > next_table) {
293 err = -EINVAL;
294 goto insanity;
295 }
296
297 /* Sanity check inode_table */
298 if (msblk->inode_table >= msblk->directory_table) {
299 err = -EINVAL;
300 goto insanity;
301 }
302
303 /* allocate root */
304 root = new_inode(sb);
305 if (!root) {
306 err = -ENOMEM;
307 goto failed_mount;
308 }
309
310 err = squashfs_read_inode(root, root_inode);
311 if (err) {
312 make_bad_inode(root);
313 iput(root);
314 goto failed_mount;
315 }
316 insert_inode_hash(root);
317
318 sb->s_root = d_make_root(root);
319 if (sb->s_root == NULL) {
320 ERROR("Root inode create failed\n");
321 err = -ENOMEM;
322 goto failed_mount;
323 }
324
325 TRACE("Leaving squashfs_fill_super\n");
326 kfree(sblk);
327 return 0;
328
329insanity:
330 errorf(fc, "squashfs image failed sanity check");
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_destroy(msblk);
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
346static int squashfs_get_tree(struct fs_context *fc)
347{
348 return get_tree_bdev(fc, squashfs_fill_super);
349}
350
351static int squashfs_reconfigure(struct fs_context *fc)
352{
353 sync_filesystem(fc->root->d_sb);
354 fc->sb_flags |= SB_RDONLY;
355 return 0;
356}
357
358static const struct fs_context_operations squashfs_context_ops = {
359 .get_tree = squashfs_get_tree,
360 .reconfigure = squashfs_reconfigure,
361};
362
363static int squashfs_init_fs_context(struct fs_context *fc)
364{
365 fc->ops = &squashfs_context_ops;
366 return 0;
367}
368
369static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
370{
371 struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
372 u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
373
374 TRACE("Entered squashfs_statfs\n");
375
376 buf->f_type = SQUASHFS_MAGIC;
377 buf->f_bsize = msblk->block_size;
378 buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
379 buf->f_bfree = buf->f_bavail = 0;
380 buf->f_files = msblk->inodes;
381 buf->f_ffree = 0;
382 buf->f_namelen = SQUASHFS_NAME_LEN;
383 buf->f_fsid.val[0] = (u32)id;
384 buf->f_fsid.val[1] = (u32)(id >> 32);
385
386 return 0;
387}
388
389
390static void squashfs_put_super(struct super_block *sb)
391{
392 if (sb->s_fs_info) {
393 struct squashfs_sb_info *sbi = sb->s_fs_info;
394 squashfs_cache_delete(sbi->block_cache);
395 squashfs_cache_delete(sbi->fragment_cache);
396 squashfs_cache_delete(sbi->read_page);
397 squashfs_decompressor_destroy(sbi);
398 kfree(sbi->id_table);
399 kfree(sbi->fragment_index);
400 kfree(sbi->meta_index);
401 kfree(sbi->inode_lookup_table);
402 kfree(sbi->xattr_id_table);
403 kfree(sb->s_fs_info);
404 sb->s_fs_info = NULL;
405 }
406}
407
408static struct kmem_cache *squashfs_inode_cachep;
409
410
411static void init_once(void *foo)
412{
413 struct squashfs_inode_info *ei = foo;
414
415 inode_init_once(&ei->vfs_inode);
416}
417
418
419static int __init init_inodecache(void)
420{
421 squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
422 sizeof(struct squashfs_inode_info), 0,
423 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
424 init_once);
425
426 return squashfs_inode_cachep ? 0 : -ENOMEM;
427}
428
429
430static void destroy_inodecache(void)
431{
432 /*
433 * Make sure all delayed rcu free inodes are flushed before we
434 * destroy cache.
435 */
436 rcu_barrier();
437 kmem_cache_destroy(squashfs_inode_cachep);
438}
439
440
441static int __init init_squashfs_fs(void)
442{
443 int err = init_inodecache();
444
445 if (err)
446 return err;
447
448 err = register_filesystem(&squashfs_fs_type);
449 if (err) {
450 destroy_inodecache();
451 return err;
452 }
453
454 pr_info("version 4.0 (2009/01/31) Phillip Lougher\n");
455
456 return 0;
457}
458
459
460static void __exit exit_squashfs_fs(void)
461{
462 unregister_filesystem(&squashfs_fs_type);
463 destroy_inodecache();
464}
465
466
467static struct inode *squashfs_alloc_inode(struct super_block *sb)
468{
469 struct squashfs_inode_info *ei =
470 kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
471
472 return ei ? &ei->vfs_inode : NULL;
473}
474
475
476static void squashfs_free_inode(struct inode *inode)
477{
478 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
479}
480
481static struct file_system_type squashfs_fs_type = {
482 .owner = THIS_MODULE,
483 .name = "squashfs",
484 .init_fs_context = squashfs_init_fs_context,
485 .kill_sb = kill_block_super,
486 .fs_flags = FS_REQUIRES_DEV
487};
488MODULE_ALIAS_FS("squashfs");
489
490static const struct super_operations squashfs_super_ops = {
491 .alloc_inode = squashfs_alloc_inode,
492 .free_inode = squashfs_free_inode,
493 .statfs = squashfs_statfs,
494 .put_super = squashfs_put_super,
495};
496
497module_init(init_squashfs_fs);
498module_exit(exit_squashfs_fs);
499MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
500MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
501MODULE_LICENSE("GPL");