Commit | Line | Data |
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0aa66619 PL |
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@lougher.demon.co.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> | |
405f5571 | 33 | #include <linux/smp_lock.h> |
0aa66619 PL |
34 | #include <linux/mutex.h> |
35 | #include <linux/pagemap.h> | |
36 | #include <linux/init.h> | |
37 | #include <linux/module.h> | |
1bcbf313 | 38 | #include <linux/magic.h> |
0aa66619 PL |
39 | |
40 | #include "squashfs_fs.h" | |
41 | #include "squashfs_fs_sb.h" | |
42 | #include "squashfs_fs_i.h" | |
43 | #include "squashfs.h" | |
4c0f0bb2 | 44 | #include "decompressor.h" |
0aa66619 PL |
45 | |
46 | static struct file_system_type squashfs_fs_type; | |
b87221de | 47 | static const struct super_operations squashfs_super_ops; |
0aa66619 | 48 | |
4c0f0bb2 PL |
49 | static const struct squashfs_decompressor *supported_squashfs_filesystem(short |
50 | major, short minor, short id) | |
0aa66619 | 51 | { |
4c0f0bb2 PL |
52 | const struct squashfs_decompressor *decompressor; |
53 | ||
0aa66619 PL |
54 | if (major < SQUASHFS_MAJOR) { |
55 | ERROR("Major/Minor mismatch, older Squashfs %d.%d " | |
56 | "filesystems are unsupported\n", major, minor); | |
4c0f0bb2 | 57 | return NULL; |
0aa66619 PL |
58 | } else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) { |
59 | ERROR("Major/Minor mismatch, trying to mount newer " | |
60 | "%d.%d filesystem\n", major, minor); | |
61 | ERROR("Please update your kernel\n"); | |
4c0f0bb2 | 62 | return NULL; |
0aa66619 PL |
63 | } |
64 | ||
4c0f0bb2 PL |
65 | decompressor = squashfs_lookup_decompressor(id); |
66 | if (!decompressor->supported) { | |
67 | ERROR("Filesystem uses \"%s\" compression. This is not " | |
68 | "supported\n", decompressor->name); | |
69 | return NULL; | |
70 | } | |
0aa66619 | 71 | |
4c0f0bb2 | 72 | return decompressor; |
0aa66619 PL |
73 | } |
74 | ||
75 | ||
76 | static int squashfs_fill_super(struct super_block *sb, void *data, int silent) | |
77 | { | |
78 | struct squashfs_sb_info *msblk; | |
79 | struct squashfs_super_block *sblk = NULL; | |
80 | char b[BDEVNAME_SIZE]; | |
81 | struct inode *root; | |
82 | long long root_inode; | |
83 | unsigned short flags; | |
84 | unsigned int fragments; | |
85 | u64 lookup_table_start; | |
86 | int err; | |
87 | ||
88 | TRACE("Entered squashfs_fill_superblock\n"); | |
89 | ||
90 | sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL); | |
91 | if (sb->s_fs_info == NULL) { | |
92 | ERROR("Failed to allocate squashfs_sb_info\n"); | |
93 | return -ENOMEM; | |
94 | } | |
95 | msblk = sb->s_fs_info; | |
96 | ||
0aa66619 PL |
97 | sblk = kzalloc(sizeof(*sblk), GFP_KERNEL); |
98 | if (sblk == NULL) { | |
99 | ERROR("Failed to allocate squashfs_super_block\n"); | |
100 | goto failure; | |
101 | } | |
102 | ||
103 | msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE); | |
104 | msblk->devblksize_log2 = ffz(~msblk->devblksize); | |
105 | ||
106 | mutex_init(&msblk->read_data_mutex); | |
107 | mutex_init(&msblk->meta_index_mutex); | |
108 | ||
109 | /* | |
110 | * msblk->bytes_used is checked in squashfs_read_table to ensure reads | |
111 | * are not beyond filesystem end. But as we're using | |
112 | * squashfs_read_table here to read the superblock (including the value | |
113 | * of bytes_used) we need to set it to an initial sensible dummy value | |
114 | */ | |
115 | msblk->bytes_used = sizeof(*sblk); | |
116 | err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk)); | |
117 | ||
118 | if (err < 0) { | |
119 | ERROR("unable to read squashfs_super_block\n"); | |
120 | goto failed_mount; | |
121 | } | |
122 | ||
4c0f0bb2 PL |
123 | err = -EINVAL; |
124 | ||
0aa66619 PL |
125 | /* Check it is a SQUASHFS superblock */ |
126 | sb->s_magic = le32_to_cpu(sblk->s_magic); | |
127 | if (sb->s_magic != SQUASHFS_MAGIC) { | |
128 | if (!silent) | |
129 | ERROR("Can't find a SQUASHFS superblock on %s\n", | |
130 | bdevname(sb->s_bdev, b)); | |
0aa66619 PL |
131 | goto failed_mount; |
132 | } | |
133 | ||
4c0f0bb2 PL |
134 | /* Check the MAJOR & MINOR versions and lookup compression type */ |
135 | msblk->decompressor = supported_squashfs_filesystem( | |
136 | le16_to_cpu(sblk->s_major), | |
0aa66619 PL |
137 | le16_to_cpu(sblk->s_minor), |
138 | le16_to_cpu(sblk->compression)); | |
4c0f0bb2 | 139 | if (msblk->decompressor == NULL) |
0aa66619 PL |
140 | goto failed_mount; |
141 | ||
0aa66619 PL |
142 | /* |
143 | * Check if there's xattrs in the filesystem. These are not | |
144 | * supported in this version, so warn that they will be ignored. | |
145 | */ | |
146 | if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK) | |
147 | ERROR("Xattrs in filesystem, these will be ignored\n"); | |
148 | ||
149 | /* Check the filesystem does not extend beyond the end of the | |
150 | block device */ | |
151 | msblk->bytes_used = le64_to_cpu(sblk->bytes_used); | |
152 | if (msblk->bytes_used < 0 || msblk->bytes_used > | |
153 | i_size_read(sb->s_bdev->bd_inode)) | |
154 | goto failed_mount; | |
155 | ||
156 | /* Check block size for sanity */ | |
157 | msblk->block_size = le32_to_cpu(sblk->block_size); | |
158 | if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE) | |
159 | goto failed_mount; | |
160 | ||
fffb47b8 PL |
161 | /* |
162 | * Check the system page size is not larger than the filesystem | |
163 | * block size (by default 128K). This is currently not supported. | |
164 | */ | |
165 | if (PAGE_CACHE_SIZE > msblk->block_size) { | |
166 | ERROR("Page size > filesystem block size (%d). This is " | |
167 | "currently not supported!\n", msblk->block_size); | |
168 | goto failed_mount; | |
169 | } | |
170 | ||
0aa66619 PL |
171 | msblk->block_log = le16_to_cpu(sblk->block_log); |
172 | if (msblk->block_log > SQUASHFS_FILE_MAX_LOG) | |
173 | goto failed_mount; | |
174 | ||
175 | /* Check the root inode for sanity */ | |
176 | root_inode = le64_to_cpu(sblk->root_inode); | |
177 | if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE) | |
178 | goto failed_mount; | |
179 | ||
180 | msblk->inode_table = le64_to_cpu(sblk->inode_table_start); | |
181 | msblk->directory_table = le64_to_cpu(sblk->directory_table_start); | |
182 | msblk->inodes = le32_to_cpu(sblk->inodes); | |
183 | flags = le16_to_cpu(sblk->flags); | |
184 | ||
185 | TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b)); | |
186 | TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags) | |
187 | ? "un" : ""); | |
188 | TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags) | |
189 | ? "un" : ""); | |
190 | TRACE("Filesystem size %lld bytes\n", msblk->bytes_used); | |
191 | TRACE("Block size %d\n", msblk->block_size); | |
192 | TRACE("Number of inodes %d\n", msblk->inodes); | |
193 | TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments)); | |
194 | TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids)); | |
195 | TRACE("sblk->inode_table_start %llx\n", msblk->inode_table); | |
196 | TRACE("sblk->directory_table_start %llx\n", msblk->directory_table); | |
197 | TRACE("sblk->fragment_table_start %llx\n", | |
198 | (u64) le64_to_cpu(sblk->fragment_table_start)); | |
199 | TRACE("sblk->id_table_start %llx\n", | |
200 | (u64) le64_to_cpu(sblk->id_table_start)); | |
201 | ||
202 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
203 | sb->s_flags |= MS_RDONLY; | |
204 | sb->s_op = &squashfs_super_ops; | |
205 | ||
206 | err = -ENOMEM; | |
207 | ||
4c0f0bb2 PL |
208 | msblk->stream = squashfs_decompressor_init(msblk); |
209 | if (msblk->stream == NULL) | |
210 | goto failed_mount; | |
211 | ||
0aa66619 PL |
212 | msblk->block_cache = squashfs_cache_init("metadata", |
213 | SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE); | |
214 | if (msblk->block_cache == NULL) | |
215 | goto failed_mount; | |
216 | ||
217 | /* Allocate read_page block */ | |
218 | msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size); | |
219 | if (msblk->read_page == NULL) { | |
220 | ERROR("Failed to allocate read_page block\n"); | |
221 | goto failed_mount; | |
222 | } | |
223 | ||
224 | /* Allocate and read id index table */ | |
225 | msblk->id_table = squashfs_read_id_index_table(sb, | |
226 | le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids)); | |
227 | if (IS_ERR(msblk->id_table)) { | |
228 | err = PTR_ERR(msblk->id_table); | |
229 | msblk->id_table = NULL; | |
230 | goto failed_mount; | |
231 | } | |
232 | ||
233 | fragments = le32_to_cpu(sblk->fragments); | |
234 | if (fragments == 0) | |
235 | goto allocate_lookup_table; | |
236 | ||
237 | msblk->fragment_cache = squashfs_cache_init("fragment", | |
238 | SQUASHFS_CACHED_FRAGMENTS, msblk->block_size); | |
239 | if (msblk->fragment_cache == NULL) { | |
240 | err = -ENOMEM; | |
241 | goto failed_mount; | |
242 | } | |
243 | ||
244 | /* Allocate and read fragment index table */ | |
245 | msblk->fragment_index = squashfs_read_fragment_index_table(sb, | |
246 | le64_to_cpu(sblk->fragment_table_start), fragments); | |
247 | if (IS_ERR(msblk->fragment_index)) { | |
248 | err = PTR_ERR(msblk->fragment_index); | |
249 | msblk->fragment_index = NULL; | |
250 | goto failed_mount; | |
251 | } | |
252 | ||
253 | allocate_lookup_table: | |
254 | lookup_table_start = le64_to_cpu(sblk->lookup_table_start); | |
255 | if (lookup_table_start == SQUASHFS_INVALID_BLK) | |
256 | goto allocate_root; | |
257 | ||
258 | /* Allocate and read inode lookup table */ | |
259 | msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb, | |
260 | lookup_table_start, msblk->inodes); | |
261 | if (IS_ERR(msblk->inode_lookup_table)) { | |
262 | err = PTR_ERR(msblk->inode_lookup_table); | |
263 | msblk->inode_lookup_table = NULL; | |
264 | goto failed_mount; | |
265 | } | |
266 | ||
267 | sb->s_export_op = &squashfs_export_ops; | |
268 | ||
269 | allocate_root: | |
270 | root = new_inode(sb); | |
271 | if (!root) { | |
272 | err = -ENOMEM; | |
273 | goto failed_mount; | |
274 | } | |
275 | ||
276 | err = squashfs_read_inode(root, root_inode); | |
277 | if (err) { | |
278 | iget_failed(root); | |
279 | goto failed_mount; | |
280 | } | |
281 | insert_inode_hash(root); | |
282 | ||
283 | sb->s_root = d_alloc_root(root); | |
284 | if (sb->s_root == NULL) { | |
285 | ERROR("Root inode create failed\n"); | |
286 | err = -ENOMEM; | |
287 | iput(root); | |
288 | goto failed_mount; | |
289 | } | |
290 | ||
291 | TRACE("Leaving squashfs_fill_super\n"); | |
292 | kfree(sblk); | |
293 | return 0; | |
294 | ||
295 | failed_mount: | |
296 | squashfs_cache_delete(msblk->block_cache); | |
297 | squashfs_cache_delete(msblk->fragment_cache); | |
298 | squashfs_cache_delete(msblk->read_page); | |
4c0f0bb2 | 299 | squashfs_decompressor_free(msblk, msblk->stream); |
0aa66619 PL |
300 | kfree(msblk->inode_lookup_table); |
301 | kfree(msblk->fragment_index); | |
302 | kfree(msblk->id_table); | |
0aa66619 PL |
303 | kfree(sb->s_fs_info); |
304 | sb->s_fs_info = NULL; | |
305 | kfree(sblk); | |
306 | return err; | |
307 | ||
308 | failure: | |
0aa66619 PL |
309 | kfree(sb->s_fs_info); |
310 | sb->s_fs_info = NULL; | |
311 | return -ENOMEM; | |
312 | } | |
313 | ||
314 | ||
315 | static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf) | |
316 | { | |
317 | struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info; | |
2fc7f562 | 318 | u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev); |
0aa66619 PL |
319 | |
320 | TRACE("Entered squashfs_statfs\n"); | |
321 | ||
322 | buf->f_type = SQUASHFS_MAGIC; | |
323 | buf->f_bsize = msblk->block_size; | |
324 | buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1; | |
325 | buf->f_bfree = buf->f_bavail = 0; | |
326 | buf->f_files = msblk->inodes; | |
327 | buf->f_ffree = 0; | |
328 | buf->f_namelen = SQUASHFS_NAME_LEN; | |
2fc7f562 CL |
329 | buf->f_fsid.val[0] = (u32)id; |
330 | buf->f_fsid.val[1] = (u32)(id >> 32); | |
0aa66619 PL |
331 | |
332 | return 0; | |
333 | } | |
334 | ||
335 | ||
336 | static int squashfs_remount(struct super_block *sb, int *flags, char *data) | |
337 | { | |
338 | *flags |= MS_RDONLY; | |
339 | return 0; | |
340 | } | |
341 | ||
342 | ||
343 | static void squashfs_put_super(struct super_block *sb) | |
344 | { | |
6cfd0148 CH |
345 | lock_kernel(); |
346 | ||
0aa66619 PL |
347 | if (sb->s_fs_info) { |
348 | struct squashfs_sb_info *sbi = sb->s_fs_info; | |
349 | squashfs_cache_delete(sbi->block_cache); | |
350 | squashfs_cache_delete(sbi->fragment_cache); | |
351 | squashfs_cache_delete(sbi->read_page); | |
4c0f0bb2 | 352 | squashfs_decompressor_free(sbi, sbi->stream); |
0aa66619 PL |
353 | kfree(sbi->id_table); |
354 | kfree(sbi->fragment_index); | |
355 | kfree(sbi->meta_index); | |
0aa66619 PL |
356 | kfree(sb->s_fs_info); |
357 | sb->s_fs_info = NULL; | |
358 | } | |
6cfd0148 CH |
359 | |
360 | unlock_kernel(); | |
0aa66619 PL |
361 | } |
362 | ||
363 | ||
364 | static int squashfs_get_sb(struct file_system_type *fs_type, int flags, | |
365 | const char *dev_name, void *data, | |
366 | struct vfsmount *mnt) | |
367 | { | |
368 | return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super, | |
369 | mnt); | |
370 | } | |
371 | ||
372 | ||
373 | static struct kmem_cache *squashfs_inode_cachep; | |
374 | ||
375 | ||
376 | static void init_once(void *foo) | |
377 | { | |
378 | struct squashfs_inode_info *ei = foo; | |
379 | ||
380 | inode_init_once(&ei->vfs_inode); | |
381 | } | |
382 | ||
383 | ||
384 | static int __init init_inodecache(void) | |
385 | { | |
386 | squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache", | |
387 | sizeof(struct squashfs_inode_info), 0, | |
388 | SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, init_once); | |
389 | ||
390 | return squashfs_inode_cachep ? 0 : -ENOMEM; | |
391 | } | |
392 | ||
393 | ||
394 | static void destroy_inodecache(void) | |
395 | { | |
396 | kmem_cache_destroy(squashfs_inode_cachep); | |
397 | } | |
398 | ||
399 | ||
400 | static int __init init_squashfs_fs(void) | |
401 | { | |
402 | int err = init_inodecache(); | |
403 | ||
404 | if (err) | |
405 | return err; | |
406 | ||
407 | err = register_filesystem(&squashfs_fs_type); | |
408 | if (err) { | |
409 | destroy_inodecache(); | |
410 | return err; | |
411 | } | |
412 | ||
118e1ef6 | 413 | printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) " |
0aa66619 PL |
414 | "Phillip Lougher\n"); |
415 | ||
416 | return 0; | |
417 | } | |
418 | ||
419 | ||
420 | static void __exit exit_squashfs_fs(void) | |
421 | { | |
422 | unregister_filesystem(&squashfs_fs_type); | |
423 | destroy_inodecache(); | |
424 | } | |
425 | ||
426 | ||
427 | static struct inode *squashfs_alloc_inode(struct super_block *sb) | |
428 | { | |
429 | struct squashfs_inode_info *ei = | |
430 | kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL); | |
431 | ||
432 | return ei ? &ei->vfs_inode : NULL; | |
433 | } | |
434 | ||
435 | ||
436 | static void squashfs_destroy_inode(struct inode *inode) | |
437 | { | |
438 | kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode)); | |
439 | } | |
440 | ||
441 | ||
442 | static struct file_system_type squashfs_fs_type = { | |
443 | .owner = THIS_MODULE, | |
444 | .name = "squashfs", | |
445 | .get_sb = squashfs_get_sb, | |
446 | .kill_sb = kill_block_super, | |
447 | .fs_flags = FS_REQUIRES_DEV | |
448 | }; | |
449 | ||
b87221de | 450 | static const struct super_operations squashfs_super_ops = { |
0aa66619 PL |
451 | .alloc_inode = squashfs_alloc_inode, |
452 | .destroy_inode = squashfs_destroy_inode, | |
453 | .statfs = squashfs_statfs, | |
454 | .put_super = squashfs_put_super, | |
455 | .remount_fs = squashfs_remount | |
456 | }; | |
457 | ||
458 | module_init(init_squashfs_fs); | |
459 | module_exit(exit_squashfs_fs); | |
460 | MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem"); | |
461 | MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>"); | |
462 | MODULE_LICENSE("GPL"); |