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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->read_data_mutex);
102 mutex_init(&msblk->meta_index_mutex);
103
104
105
106
107
108
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
123 sb->s_magic = le32_to_cpu(sblk->s_magic);
124 if (sb->s_magic != SQUASHFS_MAGIC) {
125 if (!silent)
126 ERROR("Can't find a SQUASHFS superblock on %s\n",
127 bdevname(sb->s_bdev, b));
128 goto failed_mount;
129 }
130
131
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
140
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
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
153
154
155 if (PAGE_CACHE_SIZE > msblk->block_size) {
156 ERROR("Page size > filesystem block size (%d). This is "
157 "currently not supported!\n", msblk->block_size);
158 goto failed_mount;
159 }
160
161 msblk->block_log = le16_to_cpu(sblk->block_log);
162 if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
163 goto failed_mount;
164
165
166 root_inode = le64_to_cpu(sblk->root_inode);
167 if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
168 goto failed_mount;
169
170 msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
171 msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
172 msblk->inodes = le32_to_cpu(sblk->inodes);
173 flags = le16_to_cpu(sblk->flags);
174
175 TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
176 TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
177 ? "un" : "");
178 TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
179 ? "un" : "");
180 TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
181 TRACE("Block size %d\n", msblk->block_size);
182 TRACE("Number of inodes %d\n", msblk->inodes);
183 TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
184 TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
185 TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
186 TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
187 TRACE("sblk->fragment_table_start %llx\n",
188 (u64) le64_to_cpu(sblk->fragment_table_start));
189 TRACE("sblk->id_table_start %llx\n",
190 (u64) le64_to_cpu(sblk->id_table_start));
191
192 sb->s_maxbytes = MAX_LFS_FILESIZE;
193 sb->s_flags |= MS_RDONLY;
194 sb->s_op = &squashfs_super_ops;
195
196 err = -ENOMEM;
197
198 msblk->block_cache = squashfs_cache_init("metadata",
199 SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
200 if (msblk->block_cache == NULL)
201 goto failed_mount;
202
203
204 msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
205 if (msblk->read_page == NULL) {
206 ERROR("Failed to allocate read_page block\n");
207 goto failed_mount;
208 }
209
210 msblk->stream = squashfs_decompressor_init(sb, flags);
211 if (IS_ERR(msblk->stream)) {
212 err = PTR_ERR(msblk->stream);
213 msblk->stream = NULL;
214 goto failed_mount;
215 }
216
217
218 sb->s_xattr = squashfs_xattr_handlers;
219 xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
220 if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
221 next_table = msblk->bytes_used;
222 goto allocate_id_index_table;
223 }
224
225
226 msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
227 xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
228 if (IS_ERR(msblk->xattr_id_table)) {
229 ERROR("unable to read xattr id index table\n");
230 err = PTR_ERR(msblk->xattr_id_table);
231 msblk->xattr_id_table = NULL;
232 if (err != -ENOTSUPP)
233 goto failed_mount;
234 }
235 next_table = msblk->xattr_table;
236
237allocate_id_index_table:
238
239 msblk->id_table = squashfs_read_id_index_table(sb,
240 le64_to_cpu(sblk->id_table_start), next_table,
241 le16_to_cpu(sblk->no_ids));
242 if (IS_ERR(msblk->id_table)) {
243 ERROR("unable to read id index table\n");
244 err = PTR_ERR(msblk->id_table);
245 msblk->id_table = NULL;
246 goto failed_mount;
247 }
248 next_table = le64_to_cpu(msblk->id_table[0]);
249
250
251 lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
252 if (lookup_table_start == SQUASHFS_INVALID_BLK)
253 goto handle_fragments;
254
255
256 msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
257 lookup_table_start, next_table, msblk->inodes);
258 if (IS_ERR(msblk->inode_lookup_table)) {
259 ERROR("unable to read inode lookup table\n");
260 err = PTR_ERR(msblk->inode_lookup_table);
261 msblk->inode_lookup_table = NULL;
262 goto failed_mount;
263 }
264 next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
265
266 sb->s_export_op = &squashfs_export_ops;
267
268handle_fragments:
269 fragments = le32_to_cpu(sblk->fragments);
270 if (fragments == 0)
271 goto check_directory_table;
272
273 msblk->fragment_cache = squashfs_cache_init("fragment",
274 SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
275 if (msblk->fragment_cache == NULL) {
276 err = -ENOMEM;
277 goto failed_mount;
278 }
279
280
281 msblk->fragment_index = squashfs_read_fragment_index_table(sb,
282 le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
283 if (IS_ERR(msblk->fragment_index)) {
284 ERROR("unable to read fragment index table\n");
285 err = PTR_ERR(msblk->fragment_index);
286 msblk->fragment_index = NULL;
287 goto failed_mount;
288 }
289 next_table = le64_to_cpu(msblk->fragment_index[0]);
290
291check_directory_table:
292
293 if (msblk->directory_table >= next_table) {
294 err = -EINVAL;
295 goto failed_mount;
296 }
297
298
299 if (msblk->inode_table >= msblk->directory_table) {
300 err = -EINVAL;
301 goto failed_mount;
302 }
303
304
305 root = new_inode(sb);
306 if (!root) {
307 err = -ENOMEM;
308 goto failed_mount;
309 }
310
311 err = squashfs_read_inode(root, root_inode);
312 if (err) {
313 make_bad_inode(root);
314 iput(root);
315 goto failed_mount;
316 }
317 insert_inode_hash(root);
318
319 sb->s_root = d_alloc_root(root);
320 if (sb->s_root == NULL) {
321 ERROR("Root inode create failed\n");
322 err = -ENOMEM;
323 iput(root);
324 goto failed_mount;
325 }
326
327 TRACE("Leaving squashfs_fill_super\n");
328 kfree(sblk);
329 return 0;
330
331failed_mount:
332 squashfs_cache_delete(msblk->block_cache);
333 squashfs_cache_delete(msblk->fragment_cache);
334 squashfs_cache_delete(msblk->read_page);
335 squashfs_decompressor_free(msblk, msblk->stream);
336 kfree(msblk->inode_lookup_table);
337 kfree(msblk->fragment_index);
338 kfree(msblk->id_table);
339 kfree(msblk->xattr_id_table);
340 kfree(sb->s_fs_info);
341 sb->s_fs_info = NULL;
342 kfree(sblk);
343 return err;
344}
345
346
347static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
348{
349 struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
350 u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
351
352 TRACE("Entered squashfs_statfs\n");
353
354 buf->f_type = SQUASHFS_MAGIC;
355 buf->f_bsize = msblk->block_size;
356 buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
357 buf->f_bfree = buf->f_bavail = 0;
358 buf->f_files = msblk->inodes;
359 buf->f_ffree = 0;
360 buf->f_namelen = SQUASHFS_NAME_LEN;
361 buf->f_fsid.val[0] = (u32)id;
362 buf->f_fsid.val[1] = (u32)(id >> 32);
363
364 return 0;
365}
366
367
368static int squashfs_remount(struct super_block *sb, int *flags, char *data)
369{
370 *flags |= MS_RDONLY;
371 return 0;
372}
373
374
375static void squashfs_put_super(struct super_block *sb)
376{
377 if (sb->s_fs_info) {
378 struct squashfs_sb_info *sbi = sb->s_fs_info;
379 squashfs_cache_delete(sbi->block_cache);
380 squashfs_cache_delete(sbi->fragment_cache);
381 squashfs_cache_delete(sbi->read_page);
382 squashfs_decompressor_free(sbi, sbi->stream);
383 kfree(sbi->id_table);
384 kfree(sbi->fragment_index);
385 kfree(sbi->meta_index);
386 kfree(sbi->inode_lookup_table);
387 kfree(sbi->xattr_id_table);
388 kfree(sb->s_fs_info);
389 sb->s_fs_info = NULL;
390 }
391}
392
393
394static struct dentry *squashfs_mount(struct file_system_type *fs_type,
395 int flags, const char *dev_name, void *data)
396{
397 return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
398}
399
400
401static struct kmem_cache *squashfs_inode_cachep;
402
403
404static void init_once(void *foo)
405{
406 struct squashfs_inode_info *ei = foo;
407
408 inode_init_once(&ei->vfs_inode);
409}
410
411
412static int __init init_inodecache(void)
413{
414 squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
415 sizeof(struct squashfs_inode_info), 0,
416 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, init_once);
417
418 return squashfs_inode_cachep ? 0 : -ENOMEM;
419}
420
421
422static void destroy_inodecache(void)
423{
424 kmem_cache_destroy(squashfs_inode_cachep);
425}
426
427
428static int __init init_squashfs_fs(void)
429{
430 int err = init_inodecache();
431
432 if (err)
433 return err;
434
435 err = register_filesystem(&squashfs_fs_type);
436 if (err) {
437 destroy_inodecache();
438 return err;
439 }
440
441 printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
442 "Phillip Lougher\n");
443
444 return 0;
445}
446
447
448static void __exit exit_squashfs_fs(void)
449{
450 unregister_filesystem(&squashfs_fs_type);
451 destroy_inodecache();
452}
453
454
455static struct inode *squashfs_alloc_inode(struct super_block *sb)
456{
457 struct squashfs_inode_info *ei =
458 kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
459
460 return ei ? &ei->vfs_inode : NULL;
461}
462
463
464static void squashfs_i_callback(struct rcu_head *head)
465{
466 struct inode *inode = container_of(head, struct inode, i_rcu);
467 INIT_LIST_HEAD(&inode->i_dentry);
468 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
469}
470
471static void squashfs_destroy_inode(struct inode *inode)
472{
473 call_rcu(&inode->i_rcu, squashfs_i_callback);
474}
475
476
477static struct file_system_type squashfs_fs_type = {
478 .owner = THIS_MODULE,
479 .name = "squashfs",
480 .mount = squashfs_mount,
481 .kill_sb = kill_block_super,
482 .fs_flags = FS_REQUIRES_DEV
483};
484
485static const struct super_operations squashfs_super_ops = {
486 .alloc_inode = squashfs_alloc_inode,
487 .destroy_inode = squashfs_destroy_inode,
488 .statfs = squashfs_statfs,
489 .put_super = squashfs_put_super,
490 .remount_fs = squashfs_remount
491};
492
493module_init(init_squashfs_fs);
494module_exit(exit_squashfs_fs);
495MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
496MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
497MODULE_LICENSE("GPL");
498
