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GUI: Fix Tomato RAF theme for all builds. Compilation typo.
[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / fs / romfs / super.c
blobfbfdbb62b0cc637869484053cf46acbbb2180b2d
1 /* Block- or MTD-based romfs
2 *
3 * Copyright © 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * Derived from: ROMFS file system, Linux implementation
7 *
8 * Copyright © 1997-1999 Janos Farkas <chexum@shadow.banki.hu>
9 *
10 * Using parts of the minix filesystem
11 * Copyright © 1991, 1992 Linus Torvalds
12 *
13 * and parts of the affs filesystem additionally
14 * Copyright © 1993 Ray Burr
15 * Copyright © 1996 Hans-Joachim Widmaier
16 *
17 * Changes
18 * Changed for 2.1.19 modules
19 * Jan 1997 Initial release
20 * Jun 1997 2.1.43+ changes
21 * Proper page locking in readpage
22 * Changed to work with 2.1.45+ fs
23 * Jul 1997 Fixed follow_link
24 * 2.1.47
25 * lookup shouldn't return -ENOENT
26 * from Horst von Brand:
27 * fail on wrong checksum
28 * double unlock_super was possible
29 * correct namelen for statfs
30 * spotted by Bill Hawes:
31 * readlink shouldn't iput()
32 * Jun 1998 2.1.106 from Avery Pennarun: glibc scandir()
33 * exposed a problem in readdir
34 * 2.1.107 code-freeze spellchecker run
35 * Aug 1998 2.1.118+ VFS changes
36 * Sep 1998 2.1.122 another VFS change (follow_link)
37 * Apr 1999 2.2.7 no more EBADF checking in
38 * lookup/readdir, use ERR_PTR
39 * Jun 1999 2.3.6 d_alloc_root use changed
40 * 2.3.9 clean up usage of ENOENT/negative
41 * dentries in lookup
42 * clean up page flags setting
43 * (error, uptodate, locking) in
44 * in readpage
45 * use init_special_inode for
46 * fifos/sockets (and streamline) in
47 * read_inode, fix _ops table order
48 * Aug 1999 2.3.16 __initfunc() => __init change
49 * Oct 1999 2.3.24 page->owner hack obsoleted
50 * Nov 1999 2.3.27 2.3.25+ page->offset => index change
51 *
52 *
53 * This program is free software; you can redistribute it and/or
54 * modify it under the terms of the GNU General Public Licence
55 * as published by the Free Software Foundation; either version
56 * 2 of the Licence, or (at your option) any later version.
57 */
58
59 #include <linux/module.h>
60 #include <linux/string.h>
61 #include <linux/fs.h>
62 #include <linux/time.h>
63 #include <linux/slab.h>
64 #include <linux/init.h>
65 #include <linux/blkdev.h>
66 #include <linux/parser.h>
67 #include <linux/mount.h>
68 #include <linux/namei.h>
69 #include <linux/statfs.h>
70 #include <linux/mtd/super.h>
71 #include <linux/ctype.h>
72 #include <linux/highmem.h>
73 #include <linux/pagemap.h>
74 #include <linux/uaccess.h>
75 #include "internal.h"
76
77 static struct kmem_cache *romfs_inode_cachep;
78
79 static const umode_t romfs_modemap[8] = {
80 0, /* hard link */
81 S_IFDIR | 0644, /* directory */
82 S_IFREG | 0644, /* regular file */
83 S_IFLNK | 0777, /* symlink */
84 S_IFBLK | 0600, /* blockdev */
85 S_IFCHR | 0600, /* chardev */
86 S_IFSOCK | 0644, /* socket */
87 S_IFIFO | 0644 /* FIFO */
88 };
89
90 static const unsigned char romfs_dtype_table[] = {
91 DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_SOCK, DT_FIFO
92 };
93
94 static struct inode *romfs_iget(struct super_block *sb, unsigned long pos);
95
96 /*
97 * read a page worth of data from the image
98 */
99 static int romfs_readpage(struct file *file, struct page *page)
100 {
101 struct inode *inode = page->mapping->host;
102 loff_t offset, size;
103 unsigned long fillsize, pos;
104 void *buf;
105 int ret;
106
107 buf = kmap(page);
108 if (!buf)
109 return -ENOMEM;
110
111 /* 32 bit warning -- but not for us :) */
112 offset = page_offset(page);
113 size = i_size_read(inode);
114 fillsize = 0;
115 ret = 0;
116 if (offset < size) {
117 size -= offset;
118 fillsize = size > PAGE_SIZE ? PAGE_SIZE : size;
119
120 pos = ROMFS_I(inode)->i_dataoffset + offset;
121
122 ret = romfs_dev_read(inode->i_sb, pos, buf, fillsize);
123 if (ret < 0) {
124 SetPageError(page);
125 fillsize = 0;
126 ret = -EIO;
127 }
128 }
129
130 if (fillsize < PAGE_SIZE)
131 memset(buf + fillsize, 0, PAGE_SIZE - fillsize);
132 if (ret == 0)
133 SetPageUptodate(page);
134
135 flush_dcache_page(page);
136 kunmap(page);
137 unlock_page(page);
138 return ret;
139 }
140
141 static const struct address_space_operations romfs_aops = {
142 .readpage = romfs_readpage
143 };
144
145 /*
146 * read the entries from a directory
147 */
148 static int romfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
149 {
150 struct inode *i = filp->f_dentry->d_inode;
151 struct romfs_inode ri;
152 unsigned long offset, maxoff;
153 int j, ino, nextfh;
154 int stored = 0;
155 char fsname[ROMFS_MAXFN];
156 int ret;
157
158 maxoff = romfs_maxsize(i->i_sb);
159
160 offset = filp->f_pos;
161 if (!offset) {
162 offset = i->i_ino & ROMFH_MASK;
163 ret = romfs_dev_read(i->i_sb, offset, &ri, ROMFH_SIZE);
164 if (ret < 0)
165 goto out;
166 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
167 }
168
169 /* Not really failsafe, but we are read-only... */
170 for (;;) {
171 if (!offset || offset >= maxoff) {
172 offset = maxoff;
173 filp->f_pos = offset;
174 goto out;
175 }
176 filp->f_pos = offset;
177
178 /* Fetch inode info */
179 ret = romfs_dev_read(i->i_sb, offset, &ri, ROMFH_SIZE);
180 if (ret < 0)
181 goto out;
182
183 j = romfs_dev_strnlen(i->i_sb, offset + ROMFH_SIZE,
184 sizeof(fsname) - 1);
185 if (j < 0)
186 goto out;
187
188 ret = romfs_dev_read(i->i_sb, offset + ROMFH_SIZE, fsname, j);
189 if (ret < 0)
190 goto out;
191 fsname[j] = '\0';
192
193 ino = offset;
194 nextfh = be32_to_cpu(ri.next);
195 if ((nextfh & ROMFH_TYPE) == ROMFH_HRD)
196 ino = be32_to_cpu(ri.spec);
197 if (filldir(dirent, fsname, j, offset, ino,
198 romfs_dtype_table[nextfh & ROMFH_TYPE]) < 0)
199 goto out;
200
201 stored++;
202 offset = nextfh & ROMFH_MASK;
203 }
204
205 out:
206 return stored;
207 }
208
209 /*
210 * look up an entry in a directory
211 */
212 static struct dentry *romfs_lookup(struct inode *dir, struct dentry *dentry,
213 struct nameidata *nd)
214 {
215 unsigned long offset, maxoff;
216 struct inode *inode;
217 struct romfs_inode ri;
218 const char *name; /* got from dentry */
219 int len, ret;
220
221 offset = dir->i_ino & ROMFH_MASK;
222 ret = romfs_dev_read(dir->i_sb, offset, &ri, ROMFH_SIZE);
223 if (ret < 0)
224 goto error;
225
226 /* search all the file entries in the list starting from the one
227 * pointed to by the directory's special data */
228 maxoff = romfs_maxsize(dir->i_sb);
229 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
230
231 name = dentry->d_name.name;
232 len = dentry->d_name.len;
233
234 for (;;) {
235 if (!offset || offset >= maxoff)
236 goto out0;
237
238 ret = romfs_dev_read(dir->i_sb, offset, &ri, sizeof(ri));
239 if (ret < 0)
240 goto error;
241
242 /* try to match the first 16 bytes of name */
243 ret = romfs_dev_strcmp(dir->i_sb, offset + ROMFH_SIZE, name,
244 len);
245 if (ret < 0)
246 goto error;
247 if (ret == 1)
248 break;
249
250 /* next entry */
251 offset = be32_to_cpu(ri.next) & ROMFH_MASK;
252 }
253
254 /* Hard link handling */
255 if ((be32_to_cpu(ri.next) & ROMFH_TYPE) == ROMFH_HRD)
256 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
257
258 inode = romfs_iget(dir->i_sb, offset);
259 if (IS_ERR(inode)) {
260 ret = PTR_ERR(inode);
261 goto error;
262 }
263 goto outi;
264
265 /*
266 * it's a bit funky, _lookup needs to return an error code
267 * (negative) or a NULL, both as a dentry. ENOENT should not
268 * be returned, instead we need to create a negative dentry by
269 * d_add(dentry, NULL); and return 0 as no error.
270 * (Although as I see, it only matters on writable file
271 * systems).
272 */
273 out0:
274 inode = NULL;
275 outi:
276 d_add(dentry, inode);
277 ret = 0;
278 error:
279 return ERR_PTR(ret);
280 }
281
282 static const struct file_operations romfs_dir_operations = {
283 .read = generic_read_dir,
284 .readdir = romfs_readdir,
285 };
286
287 static const struct inode_operations romfs_dir_inode_operations = {
288 .lookup = romfs_lookup,
289 };
290
291 /*
292 * get a romfs inode based on its position in the image (which doubles as the
293 * inode number)
294 */
295 static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)
296 {
297 struct romfs_inode_info *inode;
298 struct romfs_inode ri;
299 struct inode *i;
300 unsigned long nlen;
301 unsigned nextfh;
302 int ret;
303 umode_t mode;
304
305 /* we might have to traverse a chain of "hard link" file entries to get
306 * to the actual file */
307 for (;;) {
308 ret = romfs_dev_read(sb, pos, &ri, sizeof(ri));
309 if (ret < 0)
310 goto error;
311
312
313 nextfh = be32_to_cpu(ri.next);
314 if ((nextfh & ROMFH_TYPE) != ROMFH_HRD)
315 break;
316
317 pos = be32_to_cpu(ri.spec) & ROMFH_MASK;
318 }
319
320 /* determine the length of the filename */
321 nlen = romfs_dev_strnlen(sb, pos + ROMFH_SIZE, ROMFS_MAXFN);
322 if (IS_ERR_VALUE(nlen))
323 goto eio;
324
325 /* get an inode for this image position */
326 i = iget_locked(sb, pos);
327 if (!i)
328 return ERR_PTR(-ENOMEM);
329
330 if (!(i->i_state & I_NEW))
331 return i;
332
333 /* precalculate the data offset */
334 inode = ROMFS_I(i);
335 inode->i_metasize = (ROMFH_SIZE + nlen + 1 + ROMFH_PAD) & ROMFH_MASK;
336 inode->i_dataoffset = pos + inode->i_metasize;
337
338 i->i_nlink = 1; /* Hard to decide.. */
339 i->i_size = be32_to_cpu(ri.size);
340 i->i_mtime.tv_sec = i->i_atime.tv_sec = i->i_ctime.tv_sec = 0;
341 i->i_mtime.tv_nsec = i->i_atime.tv_nsec = i->i_ctime.tv_nsec = 0;
342
343 /* set up mode and ops */
344 mode = romfs_modemap[nextfh & ROMFH_TYPE];
345
346 switch (nextfh & ROMFH_TYPE) {
347 case ROMFH_DIR:
348 i->i_size = ROMFS_I(i)->i_metasize;
349 i->i_op = &romfs_dir_inode_operations;
350 i->i_fop = &romfs_dir_operations;
351 if (nextfh & ROMFH_EXEC)
352 mode |= S_IXUGO;
353 break;
354 case ROMFH_REG:
355 i->i_fop = &romfs_ro_fops;
356 i->i_data.a_ops = &romfs_aops;
357 if (i->i_sb->s_mtd)
358 i->i_data.backing_dev_info =
359 i->i_sb->s_mtd->backing_dev_info;
360 if (nextfh & ROMFH_EXEC)
361 mode |= S_IXUGO;
362 break;
363 case ROMFH_SYM:
364 i->i_op = &page_symlink_inode_operations;
365 i->i_data.a_ops = &romfs_aops;
366 mode |= S_IRWXUGO;
367 break;
368 default:
369 /* depending on MBZ for sock/fifos */
370 nextfh = be32_to_cpu(ri.spec);
371 init_special_inode(i, mode, MKDEV(nextfh >> 16,
372 nextfh & 0xffff));
373 break;
374 }
375
376 i->i_mode = mode;
377
378 unlock_new_inode(i);
379 return i;
380
381 eio:
382 ret = -EIO;
383 error:
384 printk(KERN_ERR "ROMFS: read error for inode 0x%lx\n", pos);
385 return ERR_PTR(ret);
386 }
387
388 /*
389 * allocate a new inode
390 */
391 static struct inode *romfs_alloc_inode(struct super_block *sb)
392 {
393 struct romfs_inode_info *inode;
394 inode = kmem_cache_alloc(romfs_inode_cachep, GFP_KERNEL);
395 return inode ? &inode->vfs_inode : NULL;
396 }
397
398 /*
399 * return a spent inode to the slab cache
400 */
401 static void romfs_destroy_inode(struct inode *inode)
402 {
403 kmem_cache_free(romfs_inode_cachep, ROMFS_I(inode));
404 }
405
406 /*
407 * get filesystem statistics
408 */
409 static int romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
410 {
411 struct super_block *sb = dentry->d_sb;
412 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
413
414 buf->f_type = ROMFS_MAGIC;
415 buf->f_namelen = ROMFS_MAXFN;
416 buf->f_bsize = ROMBSIZE;
417 buf->f_bfree = buf->f_bavail = buf->f_ffree;
418 buf->f_blocks =
419 (romfs_maxsize(dentry->d_sb) + ROMBSIZE - 1) >> ROMBSBITS;
420 buf->f_fsid.val[0] = (u32)id;
421 buf->f_fsid.val[1] = (u32)(id >> 32);
422 return 0;
423 }
424
425 /*
426 * remounting must involve read-only
427 */
428 static int romfs_remount(struct super_block *sb, int *flags, char *data)
429 {
430 *flags |= MS_RDONLY;
431 return 0;
432 }
433
434 static const struct super_operations romfs_super_ops = {
435 .alloc_inode = romfs_alloc_inode,
436 .destroy_inode = romfs_destroy_inode,
437 .statfs = romfs_statfs,
438 .remount_fs = romfs_remount,
439 };
440
441 /*
442 * checksum check on part of a romfs filesystem
443 */
444 static __u32 romfs_checksum(const void *data, int size)
445 {
446 const __be32 *ptr = data;
447 __u32 sum;
448
449 sum = 0;
450 size >>= 2;
451 while (size > 0) {
452 sum += be32_to_cpu(*ptr++);
453 size--;
454 }
455 return sum;
456 }
457
458 /*
459 * fill in the superblock
460 */
461 static int romfs_fill_super(struct super_block *sb, void *data, int silent)
462 {
463 struct romfs_super_block *rsb;
464 struct inode *root;
465 unsigned long pos, img_size;
466 const char *storage;
467 size_t len;
468 int ret;
469
470 #ifdef CONFIG_BLOCK
471 if (!sb->s_mtd) {
472 sb_set_blocksize(sb, ROMBSIZE);
473 } else {
474 sb->s_blocksize = ROMBSIZE;
475 sb->s_blocksize_bits = blksize_bits(ROMBSIZE);
476 }
477 #endif
478
479 sb->s_maxbytes = 0xFFFFFFFF;
480 sb->s_magic = ROMFS_MAGIC;
481 sb->s_flags |= MS_RDONLY | MS_NOATIME;
482 sb->s_op = &romfs_super_ops;
483
484 /* read the image superblock and check it */
485 rsb = kmalloc(512, GFP_KERNEL);
486 if (!rsb)
487 return -ENOMEM;
488
489 sb->s_fs_info = (void *) 512;
490 ret = romfs_dev_read(sb, 0, rsb, 512);
491 if (ret < 0)
492 goto error_rsb;
493
494 img_size = be32_to_cpu(rsb->size);
495
496 if (sb->s_mtd && img_size > sb->s_mtd->size)
497 goto error_rsb_inval;
498
499 sb->s_fs_info = (void *) img_size;
500
501 if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1 ||
502 img_size < ROMFH_SIZE) {
503 if (!silent)
504 printk(KERN_WARNING "VFS:"
505 " Can't find a romfs filesystem on dev %s.\n",
506 sb->s_id);
507 goto error_rsb_inval;
508 }
509
510 if (romfs_checksum(rsb, min_t(size_t, img_size, 512))) {
511 printk(KERN_ERR "ROMFS: bad initial checksum on dev %s.\n",
512 sb->s_id);
513 goto error_rsb_inval;
514 }
515
516 storage = sb->s_mtd ? "MTD" : "the block layer";
517
518 len = strnlen(rsb->name, ROMFS_MAXFN);
519 if (!silent)
520 printk(KERN_NOTICE "ROMFS: Mounting image '%*.*s' through %s\n",
521 (unsigned) len, (unsigned) len, rsb->name, storage);
522
523 kfree(rsb);
524 rsb = NULL;
525
526 /* find the root directory */
527 pos = (ROMFH_SIZE + len + 1 + ROMFH_PAD) & ROMFH_MASK;
528
529 root = romfs_iget(sb, pos);
530 if (IS_ERR(root))
531 goto error;
532
533 sb->s_root = d_alloc_root(root);
534 if (!sb->s_root)
535 goto error_i;
536
537 return 0;
538
539 error_i:
540 iput(root);
541 error:
542 return -EINVAL;
543 error_rsb_inval:
544 ret = -EINVAL;
545 error_rsb:
546 kfree(rsb);
547 return ret;
548 }
549
550 /*
551 * get a superblock for mounting
552 */
553 static int romfs_get_sb(struct file_system_type *fs_type,
554 int flags, const char *dev_name,
555 void *data, struct vfsmount *mnt)
556 {
557 int ret = -EINVAL;
558
559 #ifdef CONFIG_ROMFS_ON_MTD
560 ret = get_sb_mtd(fs_type, flags, dev_name, data, romfs_fill_super,
561 mnt);
562 #endif
563 #ifdef CONFIG_ROMFS_ON_BLOCK
564 if (ret == -EINVAL)
565 ret = get_sb_bdev(fs_type, flags, dev_name, data,
566 romfs_fill_super, mnt);
567 #endif
568 return ret;
569 }
570
571 /*
572 * destroy a romfs superblock in the appropriate manner
573 */
574 static void romfs_kill_sb(struct super_block *sb)
575 {
576 #ifdef CONFIG_ROMFS_ON_MTD
577 if (sb->s_mtd) {
578 kill_mtd_super(sb);
579 return;
580 }
581 #endif
582 #ifdef CONFIG_ROMFS_ON_BLOCK
583 if (sb->s_bdev) {
584 kill_block_super(sb);
585 return;
586 }
587 #endif
588 }
589
590 static struct file_system_type romfs_fs_type = {
591 .owner = THIS_MODULE,
592 .name = "romfs",
593 .get_sb = romfs_get_sb,
594 .kill_sb = romfs_kill_sb,
595 .fs_flags = FS_REQUIRES_DEV,
596 };
597
598 /*
599 * inode storage initialiser
600 */
601 static void romfs_i_init_once(void *_inode)
602 {
603 struct romfs_inode_info *inode = _inode;
604
605 inode_init_once(&inode->vfs_inode);
606 }
607
608 /*
609 * romfs module initialisation
610 */
611 static int __init init_romfs_fs(void)
612 {
613 int ret;
614
615 printk(KERN_INFO "ROMFS MTD (C) 2007 Red Hat, Inc.\n");
616
617 romfs_inode_cachep =
618 kmem_cache_create("romfs_i",
619 sizeof(struct romfs_inode_info), 0,
620 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
621 romfs_i_init_once);
622
623 if (!romfs_inode_cachep) {
624 printk(KERN_ERR
625 "ROMFS error: Failed to initialise inode cache\n");
626 return -ENOMEM;
627 }
628 ret = register_filesystem(&romfs_fs_type);
629 if (ret) {
630 printk(KERN_ERR "ROMFS error: Failed to register filesystem\n");
631 goto error_register;
632 }
633 return 0;
634
635 error_register:
636 kmem_cache_destroy(romfs_inode_cachep);
637 return ret;
638 }
639
640 /*
641 * romfs module removal
642 */
643 static void __exit exit_romfs_fs(void)
644 {
645 unregister_filesystem(&romfs_fs_type);
646 kmem_cache_destroy(romfs_inode_cachep);
647 }
648
649 module_init(init_romfs_fs);
650 module_exit(exit_romfs_fs);
651
652 MODULE_DESCRIPTION("Direct-MTD Capable RomFS");
653 MODULE_AUTHOR("Red Hat, Inc.");
654 MODULE_LICENSE("GPL"); /* Actually dual-licensed, but it doesn't matter for */
Tomato firmware and modifications.