blob: 20700b9f2b4cdf6a7e4d921e741839c1bb8427d7 [file] [log] [blame]
Phillip Lougher0aa66612009-01-05 08:46:25 +00001/*
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>
Qinghuang Feng1bcbf312009-01-15 13:51:03 -080037#include <linux/magic.h>
Phillip Lougher4b5397d2010-05-14 20:48:47 +010038#include <linux/xattr.h>
Phillip Lougher0aa66612009-01-05 08:46:25 +000039
40#include "squashfs_fs.h"
41#include "squashfs_fs_sb.h"
42#include "squashfs_fs_i.h"
43#include "squashfs.h"
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010044#include "decompressor.h"
Phillip Lougher01e5b4e2010-05-17 19:39:02 +010045#include "xattr.h"
Phillip Lougher0aa66612009-01-05 08:46:25 +000046
47static struct file_system_type squashfs_fs_type;
Alexey Dobriyanb87221d2009-09-21 17:01:09 -070048static const struct super_operations squashfs_super_ops;
Phillip Lougher0aa66612009-01-05 08:46:25 +000049
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010050static const struct squashfs_decompressor *supported_squashfs_filesystem(short
51 major, short minor, short id)
Phillip Lougher0aa66612009-01-05 08:46:25 +000052{
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010053 const struct squashfs_decompressor *decompressor;
54
Phillip Lougher0aa66612009-01-05 08:46:25 +000055 if (major < SQUASHFS_MAJOR) {
56 ERROR("Major/Minor mismatch, older Squashfs %d.%d "
57 "filesystems are unsupported\n", major, minor);
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010058 return NULL;
Phillip Lougher0aa66612009-01-05 08:46:25 +000059 } 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");
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010063 return NULL;
Phillip Lougher0aa66612009-01-05 08:46:25 +000064 }
65
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010066 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 }
Phillip Lougher0aa66612009-01-05 08:46:25 +000072
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +010073 return decompressor;
Phillip Lougher0aa66612009-01-05 08:46:25 +000074}
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;
Phillip Lougher4b5397d2010-05-14 20:48:47 +010086 u64 lookup_table_start, xattr_id_table_start;
Phillip Lougher0aa66612009-01-05 08:46:25 +000087 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
Phillip Lougher0aa66612009-01-05 08:46:25 +000098 sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
99 if (sblk == NULL) {
100 ERROR("Failed to allocate squashfs_super_block\n");
101 goto failure;
102 }
103
104 msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
105 msblk->devblksize_log2 = ffz(~msblk->devblksize);
106
107 mutex_init(&msblk->read_data_mutex);
108 mutex_init(&msblk->meta_index_mutex);
109
110 /*
111 * msblk->bytes_used is checked in squashfs_read_table to ensure reads
112 * are not beyond filesystem end. But as we're using
113 * squashfs_read_table here to read the superblock (including the value
114 * of bytes_used) we need to set it to an initial sensible dummy value
115 */
116 msblk->bytes_used = sizeof(*sblk);
117 err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk));
118
119 if (err < 0) {
120 ERROR("unable to read squashfs_super_block\n");
121 goto failed_mount;
122 }
123
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +0100124 err = -EINVAL;
125
Phillip Lougher0aa66612009-01-05 08:46:25 +0000126 /* Check it is a SQUASHFS superblock */
127 sb->s_magic = le32_to_cpu(sblk->s_magic);
128 if (sb->s_magic != SQUASHFS_MAGIC) {
129 if (!silent)
130 ERROR("Can't find a SQUASHFS superblock on %s\n",
131 bdevname(sb->s_bdev, b));
Phillip Lougher0aa66612009-01-05 08:46:25 +0000132 goto failed_mount;
133 }
134
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +0100135 /* Check the MAJOR & MINOR versions and lookup compression type */
136 msblk->decompressor = supported_squashfs_filesystem(
137 le16_to_cpu(sblk->s_major),
Phillip Lougher0aa66612009-01-05 08:46:25 +0000138 le16_to_cpu(sblk->s_minor),
139 le16_to_cpu(sblk->compression));
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +0100140 if (msblk->decompressor == NULL)
Phillip Lougher0aa66612009-01-05 08:46:25 +0000141 goto failed_mount;
142
Phillip Lougher0aa66612009-01-05 08:46:25 +0000143 /* Check the filesystem does not extend beyond the end of the
144 block device */
145 msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
146 if (msblk->bytes_used < 0 || msblk->bytes_used >
147 i_size_read(sb->s_bdev->bd_inode))
148 goto failed_mount;
149
150 /* Check block size for sanity */
151 msblk->block_size = le32_to_cpu(sblk->block_size);
152 if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
153 goto failed_mount;
154
Phillip Lougherfffb47b2009-05-13 02:59:26 +0100155 /*
156 * Check the system page size is not larger than the filesystem
157 * block size (by default 128K). This is currently not supported.
158 */
159 if (PAGE_CACHE_SIZE > msblk->block_size) {
160 ERROR("Page size > filesystem block size (%d). This is "
161 "currently not supported!\n", msblk->block_size);
162 goto failed_mount;
163 }
164
Phillip Lougher0aa66612009-01-05 08:46:25 +0000165 msblk->block_log = le16_to_cpu(sblk->block_log);
166 if (msblk->block_log > SQUASHFS_FILE_MAX_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
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +0100202 msblk->stream = squashfs_decompressor_init(msblk);
203 if (msblk->stream == NULL)
204 goto failed_mount;
205
Phillip Lougher0aa66612009-01-05 08:46:25 +0000206 msblk->block_cache = squashfs_cache_init("metadata",
207 SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
208 if (msblk->block_cache == NULL)
209 goto failed_mount;
210
211 /* Allocate read_page block */
212 msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
213 if (msblk->read_page == NULL) {
214 ERROR("Failed to allocate read_page block\n");
215 goto failed_mount;
216 }
217
218 /* Allocate and read id index table */
219 msblk->id_table = squashfs_read_id_index_table(sb,
220 le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
221 if (IS_ERR(msblk->id_table)) {
222 err = PTR_ERR(msblk->id_table);
223 msblk->id_table = NULL;
224 goto failed_mount;
225 }
226
227 fragments = le32_to_cpu(sblk->fragments);
228 if (fragments == 0)
229 goto allocate_lookup_table;
230
231 msblk->fragment_cache = squashfs_cache_init("fragment",
232 SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
233 if (msblk->fragment_cache == NULL) {
234 err = -ENOMEM;
235 goto failed_mount;
236 }
237
238 /* Allocate and read fragment index table */
239 msblk->fragment_index = squashfs_read_fragment_index_table(sb,
240 le64_to_cpu(sblk->fragment_table_start), fragments);
241 if (IS_ERR(msblk->fragment_index)) {
242 err = PTR_ERR(msblk->fragment_index);
243 msblk->fragment_index = NULL;
244 goto failed_mount;
245 }
246
247allocate_lookup_table:
248 lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
249 if (lookup_table_start == SQUASHFS_INVALID_BLK)
Phillip Lougher4b5397d2010-05-14 20:48:47 +0100250 goto allocate_xattr_table;
Phillip Lougher0aa66612009-01-05 08:46:25 +0000251
252 /* Allocate and read inode lookup table */
253 msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
254 lookup_table_start, msblk->inodes);
255 if (IS_ERR(msblk->inode_lookup_table)) {
256 err = PTR_ERR(msblk->inode_lookup_table);
257 msblk->inode_lookup_table = NULL;
258 goto failed_mount;
259 }
260
261 sb->s_export_op = &squashfs_export_ops;
262
Phillip Lougher4b5397d2010-05-14 20:48:47 +0100263allocate_xattr_table:
Phillip Lougher67f66cc2010-05-17 04:06:56 +0100264 sb->s_xattr = squashfs_xattr_handlers;
Phillip Lougher4b5397d2010-05-14 20:48:47 +0100265 xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
266 if (xattr_id_table_start == SQUASHFS_INVALID_BLK)
267 goto allocate_root;
268
269 /* Allocate and read xattr id lookup table */
270 msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
271 xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
272 if (IS_ERR(msblk->xattr_id_table)) {
273 err = PTR_ERR(msblk->xattr_id_table);
274 msblk->xattr_id_table = NULL;
Phillip Lougher01e5b4e2010-05-17 19:39:02 +0100275 if (err != -ENOTSUPP)
276 goto failed_mount;
Phillip Lougher4b5397d2010-05-14 20:48:47 +0100277 }
Phillip Lougher0aa66612009-01-05 08:46:25 +0000278allocate_root:
279 root = new_inode(sb);
280 if (!root) {
281 err = -ENOMEM;
282 goto failed_mount;
283 }
284
285 err = squashfs_read_inode(root, root_inode);
286 if (err) {
Phillip Lougher1cb08e92010-04-16 01:01:36 +0100287 make_bad_inode(root);
288 iput(root);
Phillip Lougher0aa66612009-01-05 08:46:25 +0000289 goto failed_mount;
290 }
291 insert_inode_hash(root);
292
293 sb->s_root = d_alloc_root(root);
294 if (sb->s_root == NULL) {
295 ERROR("Root inode create failed\n");
296 err = -ENOMEM;
297 iput(root);
298 goto failed_mount;
299 }
300
301 TRACE("Leaving squashfs_fill_super\n");
302 kfree(sblk);
303 return 0;
304
305failed_mount:
306 squashfs_cache_delete(msblk->block_cache);
307 squashfs_cache_delete(msblk->fragment_cache);
308 squashfs_cache_delete(msblk->read_page);
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +0100309 squashfs_decompressor_free(msblk, msblk->stream);
Phillip Lougher0aa66612009-01-05 08:46:25 +0000310 kfree(msblk->inode_lookup_table);
311 kfree(msblk->fragment_index);
312 kfree(msblk->id_table);
Phillip Lougher4b5397d2010-05-14 20:48:47 +0100313 kfree(msblk->xattr_id_table);
Phillip Lougher0aa66612009-01-05 08:46:25 +0000314 kfree(sb->s_fs_info);
315 sb->s_fs_info = NULL;
316 kfree(sblk);
317 return err;
318
319failure:
Phillip Lougher0aa66612009-01-05 08:46:25 +0000320 kfree(sb->s_fs_info);
321 sb->s_fs_info = NULL;
322 return -ENOMEM;
323}
324
325
326static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
327{
328 struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
Coly Li2fc7f562009-04-02 16:59:42 -0700329 u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
Phillip Lougher0aa66612009-01-05 08:46:25 +0000330
331 TRACE("Entered squashfs_statfs\n");
332
333 buf->f_type = SQUASHFS_MAGIC;
334 buf->f_bsize = msblk->block_size;
335 buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
336 buf->f_bfree = buf->f_bavail = 0;
337 buf->f_files = msblk->inodes;
338 buf->f_ffree = 0;
339 buf->f_namelen = SQUASHFS_NAME_LEN;
Coly Li2fc7f562009-04-02 16:59:42 -0700340 buf->f_fsid.val[0] = (u32)id;
341 buf->f_fsid.val[1] = (u32)(id >> 32);
Phillip Lougher0aa66612009-01-05 08:46:25 +0000342
343 return 0;
344}
345
346
347static int squashfs_remount(struct super_block *sb, int *flags, char *data)
348{
349 *flags |= MS_RDONLY;
350 return 0;
351}
352
353
354static void squashfs_put_super(struct super_block *sb)
355{
356 if (sb->s_fs_info) {
357 struct squashfs_sb_info *sbi = sb->s_fs_info;
358 squashfs_cache_delete(sbi->block_cache);
359 squashfs_cache_delete(sbi->fragment_cache);
360 squashfs_cache_delete(sbi->read_page);
Phillip Lougher4c0f0bb2009-10-06 04:04:15 +0100361 squashfs_decompressor_free(sbi, sbi->stream);
Phillip Lougher0aa66612009-01-05 08:46:25 +0000362 kfree(sbi->id_table);
363 kfree(sbi->fragment_index);
364 kfree(sbi->meta_index);
Phillip Lougher370ec3d2010-04-23 00:24:22 +0100365 kfree(sbi->inode_lookup_table);
Phillip Lougher4b5397d2010-05-14 20:48:47 +0100366 kfree(sbi->xattr_id_table);
Phillip Lougher0aa66612009-01-05 08:46:25 +0000367 kfree(sb->s_fs_info);
368 sb->s_fs_info = NULL;
369 }
370}
371
372
Al Viro152a0832010-07-25 00:46:55 +0400373static struct dentry *squashfs_mount(struct file_system_type *fs_type, int flags,
374 const char *dev_name, void *data)
Phillip Lougher0aa66612009-01-05 08:46:25 +0000375{
Al Viro152a0832010-07-25 00:46:55 +0400376 return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
Phillip Lougher0aa66612009-01-05 08:46:25 +0000377}
378
379
380static struct kmem_cache *squashfs_inode_cachep;
381
382
383static void init_once(void *foo)
384{
385 struct squashfs_inode_info *ei = foo;
386
387 inode_init_once(&ei->vfs_inode);
388}
389
390
391static int __init init_inodecache(void)
392{
393 squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
394 sizeof(struct squashfs_inode_info), 0,
395 SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, init_once);
396
397 return squashfs_inode_cachep ? 0 : -ENOMEM;
398}
399
400
401static void destroy_inodecache(void)
402{
403 kmem_cache_destroy(squashfs_inode_cachep);
404}
405
406
407static int __init init_squashfs_fs(void)
408{
409 int err = init_inodecache();
410
411 if (err)
412 return err;
413
414 err = register_filesystem(&squashfs_fs_type);
415 if (err) {
416 destroy_inodecache();
417 return err;
418 }
419
Phillip Lougher118e1ef2009-03-05 00:31:12 +0000420 printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
Phillip Lougher0aa66612009-01-05 08:46:25 +0000421 "Phillip Lougher\n");
422
423 return 0;
424}
425
426
427static void __exit exit_squashfs_fs(void)
428{
429 unregister_filesystem(&squashfs_fs_type);
430 destroy_inodecache();
431}
432
433
434static struct inode *squashfs_alloc_inode(struct super_block *sb)
435{
436 struct squashfs_inode_info *ei =
437 kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
438
439 return ei ? &ei->vfs_inode : NULL;
440}
441
442
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100443static void squashfs_i_callback(struct rcu_head *head)
444{
445 struct inode *inode = container_of(head, struct inode, i_rcu);
446 INIT_LIST_HEAD(&inode->i_dentry);
447 kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
448}
449
Phillip Lougher0aa66612009-01-05 08:46:25 +0000450static void squashfs_destroy_inode(struct inode *inode)
451{
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100452 call_rcu(&inode->i_rcu, squashfs_i_callback);
Phillip Lougher0aa66612009-01-05 08:46:25 +0000453}
454
455
456static struct file_system_type squashfs_fs_type = {
457 .owner = THIS_MODULE,
458 .name = "squashfs",
Al Viro152a0832010-07-25 00:46:55 +0400459 .mount = squashfs_mount,
Phillip Lougher0aa66612009-01-05 08:46:25 +0000460 .kill_sb = kill_block_super,
461 .fs_flags = FS_REQUIRES_DEV
462};
463
Alexey Dobriyanb87221d2009-09-21 17:01:09 -0700464static const struct super_operations squashfs_super_ops = {
Phillip Lougher0aa66612009-01-05 08:46:25 +0000465 .alloc_inode = squashfs_alloc_inode,
466 .destroy_inode = squashfs_destroy_inode,
467 .statfs = squashfs_statfs,
468 .put_super = squashfs_put_super,
469 .remount_fs = squashfs_remount
470};
471
472module_init(init_squashfs_fs);
473module_exit(exit_squashfs_fs);
474MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
475MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
476MODULE_LICENSE("GPL");