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30#include <linux/fs.h>
31#include <linux/vfs.h>
32#include <linux/slab.h>
33#include <linux/smp_lock.h>
34#include <linux/mutex.h>
35#include <linux/pagemap.h>
36#include <linux/init.h>
37#include <linux/module.h>
38#include <linux/zlib.h>
39#include <linux/magic.h>
40
41#include "squashfs_fs.h"
42#include "squashfs_fs_sb.h"
43#include "squashfs_fs_i.h"
44#include "squashfs.h"
45
46static struct file_system_type squashfs_fs_type;
47static const struct super_operations squashfs_super_ops;
48
49static int supported_squashfs_filesystem(short major, short minor, short comp)
50{
51 if (major < SQUASHFS_MAJOR) {
52 ERROR("Major/Minor mismatch, older Squashfs %d.%d "
53 "filesystems are unsupported\n", major, minor);
54 return -EINVAL;
55 } else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
56 ERROR("Major/Minor mismatch, trying to mount newer "
57 "%d.%d filesystem\n", major, minor);
58 ERROR("Please update your kernel\n");
59 return -EINVAL;
60 }
61
62 if (comp != ZLIB_COMPRESSION)
63 return -EINVAL;
64
65 return 0;
66}
67
68
69static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
70{
71 struct squashfs_sb_info *msblk;
72 struct squashfs_super_block *sblk = NULL;
73 char b[BDEVNAME_SIZE];
74 struct inode *root;
75 long long root_inode;
76 unsigned short flags;
77 unsigned int fragments;
78 u64 lookup_table_start;
79 int err;
80
81 TRACE("Entered squashfs_fill_superblock\n");
82
83 sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
84 if (sb->s_fs_info == NULL) {
85 ERROR("Failed to allocate squashfs_sb_info\n");
86 return -ENOMEM;
87 }
88 msblk = sb->s_fs_info;
89
90 msblk->stream.workspace = kmalloc(zlib_inflate_workspacesize(),
91 GFP_KERNEL);
92 if (msblk->stream.workspace == NULL) {
93 ERROR("Failed to allocate zlib workspace\n");
94 goto failure;
95 }
96
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
111
112
113
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
123
124 sb->s_magic = le32_to_cpu(sblk->s_magic);
125 if (sb->s_magic != SQUASHFS_MAGIC) {
126 if (!silent)
127 ERROR("Can't find a SQUASHFS superblock on %s\n",
128 bdevname(sb->s_bdev, b));
129 err = -EINVAL;
130 goto failed_mount;
131 }
132
133
134 err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
135 le16_to_cpu(sblk->s_minor),
136 le16_to_cpu(sblk->compression));
137 if (err < 0)
138 goto failed_mount;
139
140 err = -EINVAL;
141
142
143
144
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
150
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
157 msblk->block_size = le32_to_cpu(sblk->block_size);
158 if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
159 goto failed_mount;
160
161
162
163
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
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
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
208 msblk->block_cache = squashfs_cache_init("metadata",
209 SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
210 if (msblk->block_cache == NULL)
211 goto failed_mount;
212
213
214 msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
215 if (msblk->read_page == NULL) {
216 ERROR("Failed to allocate read_page block\n");
217 goto failed_mount;
218 }
219
220
221 msblk->id_table = squashfs_read_id_index_table(sb,
222 le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
223 if (IS_ERR(msblk->id_table)) {
224 err = PTR_ERR(msblk->id_table);
225 msblk->id_table = NULL;
226 goto failed_mount;
227 }
228
229 fragments = le32_to_cpu(sblk->fragments);
230 if (fragments == 0)
231 goto allocate_lookup_table;
232
233 msblk->fragment_cache = squashfs_cache_init("fragment",
234 SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
235 if (msblk->fragment_cache == NULL) {
236 err = -ENOMEM;
237 goto failed_mount;
238 }
239
240
241 msblk->fragment_index = squashfs_read_fragment_index_table(sb,
242 le64_to_cpu(sblk->fragment_table_start), fragments);
243 if (IS_ERR(msblk->fragment_index)) {
244 err = PTR_ERR(msblk->fragment_index);
245 msblk->fragment_index = NULL;
246 goto failed_mount;
247 }
248
249allocate_lookup_table:
250 lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
251 if (lookup_table_start == SQUASHFS_INVALID_BLK)
252 goto allocate_root;
253
254
255 msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
256 lookup_table_start, msblk->inodes);
257 if (IS_ERR(msblk->inode_lookup_table)) {
258 err = PTR_ERR(msblk->inode_lookup_table);
259 msblk->inode_lookup_table = NULL;
260 goto failed_mount;
261 }
262
263 sb->s_export_op = &squashfs_export_ops;
264
265allocate_root:
266 root = new_inode(sb);
267 if (!root) {
268 err = -ENOMEM;
269 goto failed_mount;
270 }
271
272 err = squashfs_read_inode(root, root_inode);
273 if (err) {
274 iget_failed(root);
275 goto failed_mount;
276 }
277 insert_inode_hash(root);
278
279 sb->s_root = d_alloc_root(root);
280 if (sb->s_root == NULL) {
281 ERROR("Root inode create failed\n");
282 err = -ENOMEM;
283 iput(root);
284 goto failed_mount;
285 }
286
287 TRACE("Leaving squashfs_fill_super\n");
288 kfree(sblk);
289 return 0;
290
291failed_mount:
292 squashfs_cache_delete(msblk->block_cache);
293 squashfs_cache_delete(msblk->fragment_cache);
294 squashfs_cache_delete(msblk->read_page);
295 kfree(msblk->inode_lookup_table);
296 kfree(msblk->fragment_index);
297 kfree(msblk->id_table);
298 kfree(msblk->stream.workspace);
299 kfree(sb->s_fs_info);
300 sb->s_fs_info = NULL;
301 kfree(sblk);
302 return err;
303
304failure:
305 kfree(msblk->stream.workspace);
306 kfree(sb->s_fs_info);
307 sb->s_fs_info = NULL;
308 return -ENOMEM;
309}
310
311
312static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
313{
314 struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
315 u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
316
317 TRACE("Entered squashfs_statfs\n");
318
319 buf->f_type = SQUASHFS_MAGIC;
320 buf->f_bsize = msblk->block_size;
321 buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
322 buf->f_bfree = buf->f_bavail = 0;
323 buf->f_files = msblk->inodes;
324 buf->f_ffree = 0;
325 buf->f_namelen = SQUASHFS_NAME_LEN;
326 buf->f_fsid.val[0] = (u32)id;
327 buf->f_fsid.val[1] = (u32)(id >> 32);
328
329 return 0;
330}
331
332
333static int squashfs_remount(struct super_block *sb, int *flags, char *data)
334{
335 *flags |= MS_RDONLY;
336 return 0;
337}
338
339
340static void squashfs_put_super(struct super_block *sb)
341{
342 lock_kernel();
343
344 if (sb->s_fs_info) {
345 struct squashfs_sb_info *sbi = sb->s_fs_info;
346 squashfs_cache_delete(sbi->block_cache);
347 squashfs_cache_delete(sbi->fragment_cache);
348 squashfs_cache_delete(sbi->read_page);
349 kfree(sbi->id_table);
350 kfree(sbi->fragment_index);
351 kfree(sbi->meta_index);
352 kfree(sbi->stream.workspace);
353 kfree(sb->s_fs_info);
354 sb->s_fs_info = NULL;
355 }
356
357 unlock_kernel();
358}
359
360
361static int squashfs_get_sb(struct file_system_type *fs_type, int flags,
362 const char *dev_name, void *data,
363 struct vfsmount *mnt)
364{
365 return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super,
366 mnt);
367}
368
369
370static struct kmem_cache *squashfs_inode_cachep;
371
372
373static void init_once(void *foo)
374{
375 struct squashfs_inode_info *ei = foo;
376
377 inode_init_once(&ei->vfs_inode);
378}
379
380
381static int __init init_inodecache(void)
382{
383 squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
384 sizeof(struct squashfs_inode_info), 0,
385 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, init_once);
386
387 return squashfs_inode_cachep ? 0 : -ENOMEM;
388}
389
390
391static void destroy_inodecache(void)
392{
393 kmem_cache_destroy(squashfs_inode_cachep);
394}
395
396
397static int __init init_squashfs_fs(void)
398{
399 int err = init_inodecache();
400
401 if (err)
402 return err;
403
404 err = register_filesystem(&squashfs_fs_type);
405 if (err) {
406 destroy_inodecache();
407 return err;
408 }
409
410 printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
411 "Phillip Lougher\n");
412
413 return 0;
414}
415
416
417static void __exit exit_squashfs_fs(void)
418{
419 unregister_filesystem(&squashfs_fs_type);
420 destroy_inodecache();
421}
422
423
424static struct inode *squashfs_alloc_inode(struct super_block *sb)
425{
426 struct squashfs_inode_info *ei =
427 kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
428
429 return ei ? &ei->vfs_inode : NULL;
430}
431
432
433static void squashfs_destroy_inode(struct inode *inode)
434{
435 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
436}
437
438
439static struct file_system_type squashfs_fs_type = {
440 .owner = THIS_MODULE,
441 .name = "squashfs",
442 .get_sb = squashfs_get_sb,
443 .kill_sb = kill_block_super,
444 .fs_flags = FS_REQUIRES_DEV
445};
446
447static const struct super_operations squashfs_super_ops = {
448 .alloc_inode = squashfs_alloc_inode,
449 .destroy_inode = squashfs_destroy_inode,
450 .statfs = squashfs_statfs,
451 .put_super = squashfs_put_super,
452 .remount_fs = squashfs_remount
453};
454
455module_init(init_squashfs_fs);
456module_exit(exit_squashfs_fs);
457MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
458MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
459MODULE_LICENSE("GPL");
460
