diff options
Diffstat (limited to 'fs/squashfs/super.c')
-rw-r--r-- | fs/squashfs/super.c | 441 |
1 files changed, 441 insertions, 0 deletions
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c new file mode 100644 index 000000000000..071df5b5b491 --- /dev/null +++ b/fs/squashfs/super.c | |||
@@ -0,0 +1,441 @@ | |||
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> | ||
33 | #include <linux/mutex.h> | ||
34 | #include <linux/pagemap.h> | ||
35 | #include <linux/init.h> | ||
36 | #include <linux/module.h> | ||
37 | #include <linux/zlib.h> | ||
38 | #include <linux/magic.h> | ||
39 | |||
40 | #include "squashfs_fs.h" | ||
41 | #include "squashfs_fs_sb.h" | ||
42 | #include "squashfs_fs_i.h" | ||
43 | #include "squashfs.h" | ||
44 | |||
45 | static struct file_system_type squashfs_fs_type; | ||
46 | static struct super_operations squashfs_super_ops; | ||
47 | |||
48 | static int supported_squashfs_filesystem(short major, short minor, short comp) | ||
49 | { | ||
50 | if (major < SQUASHFS_MAJOR) { | ||
51 | ERROR("Major/Minor mismatch, older Squashfs %d.%d " | ||
52 | "filesystems are unsupported\n", major, minor); | ||
53 | return -EINVAL; | ||
54 | } else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) { | ||
55 | ERROR("Major/Minor mismatch, trying to mount newer " | ||
56 | "%d.%d filesystem\n", major, minor); | ||
57 | ERROR("Please update your kernel\n"); | ||
58 | return -EINVAL; | ||
59 | } | ||
60 | |||
61 | if (comp != ZLIB_COMPRESSION) | ||
62 | return -EINVAL; | ||
63 | |||
64 | return 0; | ||
65 | } | ||
66 | |||
67 | |||
68 | static int squashfs_fill_super(struct super_block *sb, void *data, int silent) | ||
69 | { | ||
70 | struct squashfs_sb_info *msblk; | ||
71 | struct squashfs_super_block *sblk = NULL; | ||
72 | char b[BDEVNAME_SIZE]; | ||
73 | struct inode *root; | ||
74 | long long root_inode; | ||
75 | unsigned short flags; | ||
76 | unsigned int fragments; | ||
77 | u64 lookup_table_start; | ||
78 | int err; | ||
79 | |||
80 | TRACE("Entered squashfs_fill_superblock\n"); | ||
81 | |||
82 | sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL); | ||
83 | if (sb->s_fs_info == NULL) { | ||
84 | ERROR("Failed to allocate squashfs_sb_info\n"); | ||
85 | return -ENOMEM; | ||
86 | } | ||
87 | msblk = sb->s_fs_info; | ||
88 | |||
89 | msblk->stream.workspace = kmalloc(zlib_inflate_workspacesize(), | ||
90 | GFP_KERNEL); | ||
91 | if (msblk->stream.workspace == NULL) { | ||
92 | ERROR("Failed to allocate zlib workspace\n"); | ||
93 | goto failure; | ||
94 | } | ||
95 | |||
96 | sblk = kzalloc(sizeof(*sblk), GFP_KERNEL); | ||
97 | if (sblk == NULL) { | ||
98 | ERROR("Failed to allocate squashfs_super_block\n"); | ||
99 | goto failure; | ||
100 | } | ||
101 | |||
102 | msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE); | ||
103 | msblk->devblksize_log2 = ffz(~msblk->devblksize); | ||
104 | |||
105 | mutex_init(&msblk->read_data_mutex); | ||
106 | mutex_init(&msblk->meta_index_mutex); | ||
107 | |||
108 | /* | ||
109 | * msblk->bytes_used is checked in squashfs_read_table to ensure reads | ||
110 | * are not beyond filesystem end. But as we're using | ||
111 | * squashfs_read_table here to read the superblock (including the value | ||
112 | * of bytes_used) we need to set it to an initial sensible dummy value | ||
113 | */ | ||
114 | msblk->bytes_used = sizeof(*sblk); | ||
115 | err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk)); | ||
116 | |||
117 | if (err < 0) { | ||
118 | ERROR("unable to read squashfs_super_block\n"); | ||
119 | goto failed_mount; | ||
120 | } | ||
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 | err = -EINVAL; | ||
129 | goto failed_mount; | ||
130 | } | ||
131 | |||
132 | /* Check the MAJOR & MINOR versions and compression type */ | ||
133 | err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major), | ||
134 | le16_to_cpu(sblk->s_minor), | ||
135 | le16_to_cpu(sblk->compression)); | ||
136 | if (err < 0) | ||
137 | goto failed_mount; | ||
138 | |||
139 | err = -EINVAL; | ||
140 | |||
141 | /* | ||
142 | * Check if there's xattrs in the filesystem. These are not | ||
143 | * supported in this version, so warn that they will be ignored. | ||
144 | */ | ||
145 | if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK) | ||
146 | ERROR("Xattrs in filesystem, these will be ignored\n"); | ||
147 | |||
148 | /* Check the filesystem does not extend beyond the end of the | ||
149 | block device */ | ||
150 | msblk->bytes_used = le64_to_cpu(sblk->bytes_used); | ||
151 | if (msblk->bytes_used < 0 || msblk->bytes_used > | ||
152 | i_size_read(sb->s_bdev->bd_inode)) | ||
153 | goto failed_mount; | ||
154 | |||
155 | /* Check block size for sanity */ | ||
156 | msblk->block_size = le32_to_cpu(sblk->block_size); | ||
157 | if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE) | ||
158 | goto failed_mount; | ||
159 | |||
160 | msblk->block_log = le16_to_cpu(sblk->block_log); | ||
161 | if (msblk->block_log > SQUASHFS_FILE_MAX_LOG) | ||
162 | goto failed_mount; | ||
163 | |||
164 | /* Check the root inode for sanity */ | ||
165 | root_inode = le64_to_cpu(sblk->root_inode); | ||
166 | if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE) | ||
167 | goto failed_mount; | ||
168 | |||
169 | msblk->inode_table = le64_to_cpu(sblk->inode_table_start); | ||
170 | msblk->directory_table = le64_to_cpu(sblk->directory_table_start); | ||
171 | msblk->inodes = le32_to_cpu(sblk->inodes); | ||
172 | flags = le16_to_cpu(sblk->flags); | ||
173 | |||
174 | TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b)); | ||
175 | TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags) | ||
176 | ? "un" : ""); | ||
177 | TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags) | ||
178 | ? "un" : ""); | ||
179 | TRACE("Filesystem size %lld bytes\n", msblk->bytes_used); | ||
180 | TRACE("Block size %d\n", msblk->block_size); | ||
181 | TRACE("Number of inodes %d\n", msblk->inodes); | ||
182 | TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments)); | ||
183 | TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids)); | ||
184 | TRACE("sblk->inode_table_start %llx\n", msblk->inode_table); | ||
185 | TRACE("sblk->directory_table_start %llx\n", msblk->directory_table); | ||
186 | TRACE("sblk->fragment_table_start %llx\n", | ||
187 | (u64) le64_to_cpu(sblk->fragment_table_start)); | ||
188 | TRACE("sblk->id_table_start %llx\n", | ||
189 | (u64) le64_to_cpu(sblk->id_table_start)); | ||
190 | |||
191 | sb->s_maxbytes = MAX_LFS_FILESIZE; | ||
192 | sb->s_flags |= MS_RDONLY; | ||
193 | sb->s_op = &squashfs_super_ops; | ||
194 | |||
195 | err = -ENOMEM; | ||
196 | |||
197 | msblk->block_cache = squashfs_cache_init("metadata", | ||
198 | SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE); | ||
199 | if (msblk->block_cache == NULL) | ||
200 | goto failed_mount; | ||
201 | |||
202 | /* Allocate read_page block */ | ||
203 | msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size); | ||
204 | if (msblk->read_page == NULL) { | ||
205 | ERROR("Failed to allocate read_page block\n"); | ||
206 | goto failed_mount; | ||
207 | } | ||
208 | |||
209 | /* Allocate and read id index table */ | ||
210 | msblk->id_table = squashfs_read_id_index_table(sb, | ||
211 | le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids)); | ||
212 | if (IS_ERR(msblk->id_table)) { | ||
213 | err = PTR_ERR(msblk->id_table); | ||
214 | msblk->id_table = NULL; | ||
215 | goto failed_mount; | ||
216 | } | ||
217 | |||
218 | fragments = le32_to_cpu(sblk->fragments); | ||
219 | if (fragments == 0) | ||
220 | goto allocate_lookup_table; | ||
221 | |||
222 | msblk->fragment_cache = squashfs_cache_init("fragment", | ||
223 | SQUASHFS_CACHED_FRAGMENTS, msblk->block_size); | ||
224 | if (msblk->fragment_cache == NULL) { | ||
225 | err = -ENOMEM; | ||
226 | goto failed_mount; | ||
227 | } | ||
228 | |||
229 | /* Allocate and read fragment index table */ | ||
230 | msblk->fragment_index = squashfs_read_fragment_index_table(sb, | ||
231 | le64_to_cpu(sblk->fragment_table_start), fragments); | ||
232 | if (IS_ERR(msblk->fragment_index)) { | ||
233 | err = PTR_ERR(msblk->fragment_index); | ||
234 | msblk->fragment_index = NULL; | ||
235 | goto failed_mount; | ||
236 | } | ||
237 | |||
238 | allocate_lookup_table: | ||
239 | lookup_table_start = le64_to_cpu(sblk->lookup_table_start); | ||
240 | if (lookup_table_start == SQUASHFS_INVALID_BLK) | ||
241 | goto allocate_root; | ||
242 | |||
243 | /* Allocate and read inode lookup table */ | ||
244 | msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb, | ||
245 | lookup_table_start, msblk->inodes); | ||
246 | if (IS_ERR(msblk->inode_lookup_table)) { | ||
247 | err = PTR_ERR(msblk->inode_lookup_table); | ||
248 | msblk->inode_lookup_table = NULL; | ||
249 | goto failed_mount; | ||
250 | } | ||
251 | |||
252 | sb->s_export_op = &squashfs_export_ops; | ||
253 | |||
254 | allocate_root: | ||
255 | root = new_inode(sb); | ||
256 | if (!root) { | ||
257 | err = -ENOMEM; | ||
258 | goto failed_mount; | ||
259 | } | ||
260 | |||
261 | err = squashfs_read_inode(root, root_inode); | ||
262 | if (err) { | ||
263 | iget_failed(root); | ||
264 | goto failed_mount; | ||
265 | } | ||
266 | insert_inode_hash(root); | ||
267 | |||
268 | sb->s_root = d_alloc_root(root); | ||
269 | if (sb->s_root == NULL) { | ||
270 | ERROR("Root inode create failed\n"); | ||
271 | err = -ENOMEM; | ||
272 | iput(root); | ||
273 | goto failed_mount; | ||
274 | } | ||
275 | |||
276 | TRACE("Leaving squashfs_fill_super\n"); | ||
277 | kfree(sblk); | ||
278 | return 0; | ||
279 | |||
280 | failed_mount: | ||
281 | squashfs_cache_delete(msblk->block_cache); | ||
282 | squashfs_cache_delete(msblk->fragment_cache); | ||
283 | squashfs_cache_delete(msblk->read_page); | ||
284 | kfree(msblk->inode_lookup_table); | ||
285 | kfree(msblk->fragment_index); | ||
286 | kfree(msblk->id_table); | ||
287 | kfree(msblk->stream.workspace); | ||
288 | kfree(sb->s_fs_info); | ||
289 | sb->s_fs_info = NULL; | ||
290 | kfree(sblk); | ||
291 | return err; | ||
292 | |||
293 | failure: | ||
294 | kfree(msblk->stream.workspace); | ||
295 | kfree(sb->s_fs_info); | ||
296 | sb->s_fs_info = NULL; | ||
297 | return -ENOMEM; | ||
298 | } | ||
299 | |||
300 | |||
301 | static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf) | ||
302 | { | ||
303 | struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info; | ||
304 | |||
305 | TRACE("Entered squashfs_statfs\n"); | ||
306 | |||
307 | buf->f_type = SQUASHFS_MAGIC; | ||
308 | buf->f_bsize = msblk->block_size; | ||
309 | buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1; | ||
310 | buf->f_bfree = buf->f_bavail = 0; | ||
311 | buf->f_files = msblk->inodes; | ||
312 | buf->f_ffree = 0; | ||
313 | buf->f_namelen = SQUASHFS_NAME_LEN; | ||
314 | |||
315 | return 0; | ||
316 | } | ||
317 | |||
318 | |||
319 | static int squashfs_remount(struct super_block *sb, int *flags, char *data) | ||
320 | { | ||
321 | *flags |= MS_RDONLY; | ||
322 | return 0; | ||
323 | } | ||
324 | |||
325 | |||
326 | static void squashfs_put_super(struct super_block *sb) | ||
327 | { | ||
328 | if (sb->s_fs_info) { | ||
329 | struct squashfs_sb_info *sbi = sb->s_fs_info; | ||
330 | squashfs_cache_delete(sbi->block_cache); | ||
331 | squashfs_cache_delete(sbi->fragment_cache); | ||
332 | squashfs_cache_delete(sbi->read_page); | ||
333 | kfree(sbi->id_table); | ||
334 | kfree(sbi->fragment_index); | ||
335 | kfree(sbi->meta_index); | ||
336 | kfree(sbi->stream.workspace); | ||
337 | kfree(sb->s_fs_info); | ||
338 | sb->s_fs_info = NULL; | ||
339 | } | ||
340 | } | ||
341 | |||
342 | |||
343 | static int squashfs_get_sb(struct file_system_type *fs_type, int flags, | ||
344 | const char *dev_name, void *data, | ||
345 | struct vfsmount *mnt) | ||
346 | { | ||
347 | return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super, | ||
348 | mnt); | ||
349 | } | ||
350 | |||
351 | |||
352 | static struct kmem_cache *squashfs_inode_cachep; | ||
353 | |||
354 | |||
355 | static void init_once(void *foo) | ||
356 | { | ||
357 | struct squashfs_inode_info *ei = foo; | ||
358 | |||
359 | inode_init_once(&ei->vfs_inode); | ||
360 | } | ||
361 | |||
362 | |||
363 | static int __init init_inodecache(void) | ||
364 | { | ||
365 | squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache", | ||
366 | sizeof(struct squashfs_inode_info), 0, | ||
367 | SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, init_once); | ||
368 | |||
369 | return squashfs_inode_cachep ? 0 : -ENOMEM; | ||
370 | } | ||
371 | |||
372 | |||
373 | static void destroy_inodecache(void) | ||
374 | { | ||
375 | kmem_cache_destroy(squashfs_inode_cachep); | ||
376 | } | ||
377 | |||
378 | |||
379 | static int __init init_squashfs_fs(void) | ||
380 | { | ||
381 | int err = init_inodecache(); | ||
382 | |||
383 | if (err) | ||
384 | return err; | ||
385 | |||
386 | err = register_filesystem(&squashfs_fs_type); | ||
387 | if (err) { | ||
388 | destroy_inodecache(); | ||
389 | return err; | ||
390 | } | ||
391 | |||
392 | printk(KERN_INFO "squashfs: version 4.0 (2009/01/03) " | ||
393 | "Phillip Lougher\n"); | ||
394 | |||
395 | return 0; | ||
396 | } | ||
397 | |||
398 | |||
399 | static void __exit exit_squashfs_fs(void) | ||
400 | { | ||
401 | unregister_filesystem(&squashfs_fs_type); | ||
402 | destroy_inodecache(); | ||
403 | } | ||
404 | |||
405 | |||
406 | static struct inode *squashfs_alloc_inode(struct super_block *sb) | ||
407 | { | ||
408 | struct squashfs_inode_info *ei = | ||
409 | kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL); | ||
410 | |||
411 | return ei ? &ei->vfs_inode : NULL; | ||
412 | } | ||
413 | |||
414 | |||
415 | static void squashfs_destroy_inode(struct inode *inode) | ||
416 | { | ||
417 | kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode)); | ||
418 | } | ||
419 | |||
420 | |||
421 | static struct file_system_type squashfs_fs_type = { | ||
422 | .owner = THIS_MODULE, | ||
423 | .name = "squashfs", | ||
424 | .get_sb = squashfs_get_sb, | ||
425 | .kill_sb = kill_block_super, | ||
426 | .fs_flags = FS_REQUIRES_DEV | ||
427 | }; | ||
428 | |||
429 | static struct super_operations squashfs_super_ops = { | ||
430 | .alloc_inode = squashfs_alloc_inode, | ||
431 | .destroy_inode = squashfs_destroy_inode, | ||
432 | .statfs = squashfs_statfs, | ||
433 | .put_super = squashfs_put_super, | ||
434 | .remount_fs = squashfs_remount | ||
435 | }; | ||
436 | |||
437 | module_init(init_squashfs_fs); | ||
438 | module_exit(exit_squashfs_fs); | ||
439 | MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem"); | ||
440 | MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>"); | ||
441 | MODULE_LICENSE("GPL"); | ||