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