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KVM: Prevent kvm_init from corrupting debugfs structures
[linux-2.6/verdex.git] / fs / affs / super.c
blob104fdcb3a7fca3997d8740e2ed2d14ba283338c7
1 /*
2 * linux/fs/affs/inode.c
3 *
4 * (c) 1996 Hans-Joachim Widmaier - Rewritten
5 *
6 * (C) 1993 Ray Burr - Modified for Amiga FFS filesystem.
7 *
8 * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem.
9 *
10 * (C) 1991 Linus Torvalds - minix filesystem
11 */
12
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/statfs.h>
16 #include <linux/parser.h>
17 #include <linux/magic.h>
18 #include <linux/sched.h>
19 #include <linux/smp_lock.h>
20 #include "affs.h"
21
22 extern struct timezone sys_tz;
23
24 static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
25 static int affs_remount (struct super_block *sb, int *flags, char *data);
26
27 static void
28 affs_commit_super(struct super_block *sb, int clean)
29 {
30 struct affs_sb_info *sbi = AFFS_SB(sb);
31 struct buffer_head *bh = sbi->s_root_bh;
32 struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);
33
34 tail->bm_flag = cpu_to_be32(clean);
35 secs_to_datestamp(get_seconds(), &tail->disk_change);
36 affs_fix_checksum(sb, bh);
37 mark_buffer_dirty(bh);
38 }
39
40 static void
41 affs_put_super(struct super_block *sb)
42 {
43 struct affs_sb_info *sbi = AFFS_SB(sb);
44 pr_debug("AFFS: put_super()\n");
45
46 lock_kernel();
47
48 if (!(sb->s_flags & MS_RDONLY))
49 affs_commit_super(sb, 1);
50
51 kfree(sbi->s_prefix);
52 affs_free_bitmap(sb);
53 affs_brelse(sbi->s_root_bh);
54 kfree(sbi);
55 sb->s_fs_info = NULL;
56
57 unlock_kernel();
58 }
59
60 static void
61 affs_write_super(struct super_block *sb)
62 {
63 int clean = 2;
64
65 lock_super(sb);
66 if (!(sb->s_flags & MS_RDONLY)) {
67 // if (sbi->s_bitmap[i].bm_bh) {
68 // if (buffer_dirty(sbi->s_bitmap[i].bm_bh)) {
69 // clean = 0;
70 affs_commit_super(sb, clean);
71 sb->s_dirt = !clean; /* redo until bitmap synced */
72 } else
73 sb->s_dirt = 0;
74 unlock_super(sb);
75
76 pr_debug("AFFS: write_super() at %lu, clean=%d\n", get_seconds(), clean);
77 }
78
79 static int
80 affs_sync_fs(struct super_block *sb, int wait)
81 {
82 lock_super(sb);
83 affs_commit_super(sb, 2);
84 sb->s_dirt = 0;
85 unlock_super(sb);
86 return 0;
87 }
88
89 static struct kmem_cache * affs_inode_cachep;
90
91 static struct inode *affs_alloc_inode(struct super_block *sb)
92 {
93 struct affs_inode_info *i;
94
95 i = kmem_cache_alloc(affs_inode_cachep, GFP_KERNEL);
96 if (!i)
97 return NULL;
98
99 i->vfs_inode.i_version = 1;
100 i->i_lc = NULL;
101 i->i_ext_bh = NULL;
102 i->i_pa_cnt = 0;
103
104 return &i->vfs_inode;
105 }
106
107 static void affs_destroy_inode(struct inode *inode)
108 {
109 kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
110 }
111
112 static void init_once(void *foo)
113 {
114 struct affs_inode_info *ei = (struct affs_inode_info *) foo;
115
116 init_MUTEX(&ei->i_link_lock);
117 init_MUTEX(&ei->i_ext_lock);
118 inode_init_once(&ei->vfs_inode);
119 }
120
121 static int init_inodecache(void)
122 {
123 affs_inode_cachep = kmem_cache_create("affs_inode_cache",
124 sizeof(struct affs_inode_info),
125 0, (SLAB_RECLAIM_ACCOUNT|
126 SLAB_MEM_SPREAD),
127 init_once);
128 if (affs_inode_cachep == NULL)
129 return -ENOMEM;
130 return 0;
131 }
132
133 static void destroy_inodecache(void)
134 {
135 kmem_cache_destroy(affs_inode_cachep);
136 }
137
138 static const struct super_operations affs_sops = {
139 .alloc_inode = affs_alloc_inode,
140 .destroy_inode = affs_destroy_inode,
141 .write_inode = affs_write_inode,
142 .delete_inode = affs_delete_inode,
143 .clear_inode = affs_clear_inode,
144 .put_super = affs_put_super,
145 .write_super = affs_write_super,
146 .sync_fs = affs_sync_fs,
147 .statfs = affs_statfs,
148 .remount_fs = affs_remount,
149 .show_options = generic_show_options,
150 };
151
152 enum {
153 Opt_bs, Opt_mode, Opt_mufs, Opt_prefix, Opt_protect,
154 Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
155 Opt_verbose, Opt_volume, Opt_ignore, Opt_err,
156 };
157
158 static const match_table_t tokens = {
159 {Opt_bs, "bs=%u"},
160 {Opt_mode, "mode=%o"},
161 {Opt_mufs, "mufs"},
162 {Opt_prefix, "prefix=%s"},
163 {Opt_protect, "protect"},
164 {Opt_reserved, "reserved=%u"},
165 {Opt_root, "root=%u"},
166 {Opt_setgid, "setgid=%u"},
167 {Opt_setuid, "setuid=%u"},
168 {Opt_verbose, "verbose"},
169 {Opt_volume, "volume=%s"},
170 {Opt_ignore, "grpquota"},
171 {Opt_ignore, "noquota"},
172 {Opt_ignore, "quota"},
173 {Opt_ignore, "usrquota"},
174 {Opt_err, NULL},
175 };
176
177 static int
178 parse_options(char *options, uid_t *uid, gid_t *gid, int *mode, int *reserved, s32 *root,
179 int *blocksize, char **prefix, char *volume, unsigned long *mount_opts)
180 {
181 char *p;
182 substring_t args[MAX_OPT_ARGS];
183
184 /* Fill in defaults */
185
186 *uid = current_uid();
187 *gid = current_gid();
188 *reserved = 2;
189 *root = -1;
190 *blocksize = -1;
191 volume[0] = ':';
192 volume[1] = 0;
193 *mount_opts = 0;
194 if (!options)
195 return 1;
196
197 while ((p = strsep(&options, ",")) != NULL) {
198 int token, n, option;
199 if (!*p)
200 continue;
201
202 token = match_token(p, tokens, args);
203 switch (token) {
204 case Opt_bs:
205 if (match_int(&args[0], &n))
206 return -EINVAL;
207 if (n != 512 && n != 1024 && n != 2048
208 && n != 4096) {
209 printk ("AFFS: Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
210 return 0;
211 }
212 *blocksize = n;
213 break;
214 case Opt_mode:
215 if (match_octal(&args[0], &option))
216 return 1;
217 *mode = option & 0777;
218 *mount_opts |= SF_SETMODE;
219 break;
220 case Opt_mufs:
221 *mount_opts |= SF_MUFS;
222 break;
223 case Opt_prefix:
224 /* Free any previous prefix */
225 kfree(*prefix);
226 *prefix = match_strdup(&args[0]);
227 if (!*prefix)
228 return 0;
229 *mount_opts |= SF_PREFIX;
230 break;
231 case Opt_protect:
232 *mount_opts |= SF_IMMUTABLE;
233 break;
234 case Opt_reserved:
235 if (match_int(&args[0], reserved))
236 return 1;
237 break;
238 case Opt_root:
239 if (match_int(&args[0], root))
240 return 1;
241 break;
242 case Opt_setgid:
243 if (match_int(&args[0], &option))
244 return 1;
245 *gid = option;
246 *mount_opts |= SF_SETGID;
247 break;
248 case Opt_setuid:
249 if (match_int(&args[0], &option))
250 return -EINVAL;
251 *uid = option;
252 *mount_opts |= SF_SETUID;
253 break;
254 case Opt_verbose:
255 *mount_opts |= SF_VERBOSE;
256 break;
257 case Opt_volume: {
258 char *vol = match_strdup(&args[0]);
259 if (!vol)
260 return 0;
261 strlcpy(volume, vol, 32);
262 kfree(vol);
263 break;
264 }
265 case Opt_ignore:
266 /* Silently ignore the quota options */
267 break;
268 default:
269 printk("AFFS: Unrecognized mount option \"%s\" "
270 "or missing value\n", p);
271 return 0;
272 }
273 }
274 return 1;
275 }
276
277 /* This function definitely needs to be split up. Some fine day I'll
278 * hopefully have the guts to do so. Until then: sorry for the mess.
279 */
280
281 static int affs_fill_super(struct super_block *sb, void *data, int silent)
282 {
283 struct affs_sb_info *sbi;
284 struct buffer_head *root_bh = NULL;
285 struct buffer_head *boot_bh;
286 struct inode *root_inode = NULL;
287 s32 root_block;
288 int size, blocksize;
289 u32 chksum;
290 int num_bm;
291 int i, j;
292 s32 key;
293 uid_t uid;
294 gid_t gid;
295 int reserved;
296 unsigned long mount_flags;
297 int tmp_flags; /* fix remount prototype... */
298 u8 sig[4];
299 int ret = -EINVAL;
300
301 save_mount_options(sb, data);
302
303 pr_debug("AFFS: read_super(%s)\n",data ? (const char *)data : "no options");
304
305 sb->s_magic = AFFS_SUPER_MAGIC;
306 sb->s_op = &affs_sops;
307 sb->s_flags |= MS_NODIRATIME;
308
309 sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
310 if (!sbi)
311 return -ENOMEM;
312 sb->s_fs_info = sbi;
313 mutex_init(&sbi->s_bmlock);
314
315 if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
316 &blocksize,&sbi->s_prefix,
317 sbi->s_volume, &mount_flags)) {
318 printk(KERN_ERR "AFFS: Error parsing options\n");
319 return -EINVAL;
320 }
321 /* N.B. after this point s_prefix must be released */
322
323 sbi->s_flags = mount_flags;
324 sbi->s_mode = i;
325 sbi->s_uid = uid;
326 sbi->s_gid = gid;
327 sbi->s_reserved= reserved;
328
329 /* Get the size of the device in 512-byte blocks.
330 * If we later see that the partition uses bigger
331 * blocks, we will have to change it.
332 */
333
334 size = sb->s_bdev->bd_inode->i_size >> 9;
335 pr_debug("AFFS: initial blocksize=%d, #blocks=%d\n", 512, size);
336
337 affs_set_blocksize(sb, PAGE_SIZE);
338 /* Try to find root block. Its location depends on the block size. */
339
340 i = 512;
341 j = 4096;
342 if (blocksize > 0) {
343 i = j = blocksize;
344 size = size / (blocksize / 512);
345 }
346 for (blocksize = i, key = 0; blocksize <= j; blocksize <<= 1, size >>= 1) {
347 sbi->s_root_block = root_block;
348 if (root_block < 0)
349 sbi->s_root_block = (reserved + size - 1) / 2;
350 pr_debug("AFFS: setting blocksize to %d\n", blocksize);
351 affs_set_blocksize(sb, blocksize);
352 sbi->s_partition_size = size;
353
354 /* The root block location that was calculated above is not
355 * correct if the partition size is an odd number of 512-
356 * byte blocks, which will be rounded down to a number of
357 * 1024-byte blocks, and if there were an even number of
358 * reserved blocks. Ideally, all partition checkers should
359 * report the real number of blocks of the real blocksize,
360 * but since this just cannot be done, we have to try to
361 * find the root block anyways. In the above case, it is one
362 * block behind the calculated one. So we check this one, too.
363 */
364 for (num_bm = 0; num_bm < 2; num_bm++) {
365 pr_debug("AFFS: Dev %s, trying root=%u, bs=%d, "
366 "size=%d, reserved=%d\n",
367 sb->s_id,
368 sbi->s_root_block + num_bm,
369 blocksize, size, reserved);
370 root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
371 if (!root_bh)
372 continue;
373 if (!affs_checksum_block(sb, root_bh) &&
374 be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
375 be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
376 sbi->s_hashsize = blocksize / 4 - 56;
377 sbi->s_root_block += num_bm;
378 key = 1;
379 goto got_root;
380 }
381 affs_brelse(root_bh);
382 root_bh = NULL;
383 }
384 }
385 if (!silent)
386 printk(KERN_ERR "AFFS: No valid root block on device %s\n",
387 sb->s_id);
388 goto out_error;
389
390 /* N.B. after this point bh must be released */
391 got_root:
392 root_block = sbi->s_root_block;
393
394 /* Find out which kind of FS we have */
395 boot_bh = sb_bread(sb, 0);
396 if (!boot_bh) {
397 printk(KERN_ERR "AFFS: Cannot read boot block\n");
398 goto out_error;
399 }
400 memcpy(sig, boot_bh->b_data, 4);
401 brelse(boot_bh);
402 chksum = be32_to_cpu(*(__be32 *)sig);
403
404 /* Dircache filesystems are compatible with non-dircache ones
405 * when reading. As long as they aren't supported, writing is
406 * not recommended.
407 */
408 if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
409 || chksum == MUFS_DCOFS) && !(sb->s_flags & MS_RDONLY)) {
410 printk(KERN_NOTICE "AFFS: Dircache FS - mounting %s read only\n",
411 sb->s_id);
412 sb->s_flags |= MS_RDONLY;
413 }
414 switch (chksum) {
415 case MUFS_FS:
416 case MUFS_INTLFFS:
417 case MUFS_DCFFS:
418 sbi->s_flags |= SF_MUFS;
419 /* fall thru */
420 case FS_INTLFFS:
421 case FS_DCFFS:
422 sbi->s_flags |= SF_INTL;
423 break;
424 case MUFS_FFS:
425 sbi->s_flags |= SF_MUFS;
426 break;
427 case FS_FFS:
428 break;
429 case MUFS_OFS:
430 sbi->s_flags |= SF_MUFS;
431 /* fall thru */
432 case FS_OFS:
433 sbi->s_flags |= SF_OFS;
434 sb->s_flags |= MS_NOEXEC;
435 break;
436 case MUFS_DCOFS:
437 case MUFS_INTLOFS:
438 sbi->s_flags |= SF_MUFS;
439 case FS_DCOFS:
440 case FS_INTLOFS:
441 sbi->s_flags |= SF_INTL | SF_OFS;
442 sb->s_flags |= MS_NOEXEC;
443 break;
444 default:
445 printk(KERN_ERR "AFFS: Unknown filesystem on device %s: %08X\n",
446 sb->s_id, chksum);
447 goto out_error;
448 }
449
450 if (mount_flags & SF_VERBOSE) {
451 u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
452 printk(KERN_NOTICE "AFFS: Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
453 len > 31 ? 31 : len,
454 AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
455 sig, sig[3] + '0', blocksize);
456 }
457
458 sb->s_flags |= MS_NODEV | MS_NOSUID;
459
460 sbi->s_data_blksize = sb->s_blocksize;
461 if (sbi->s_flags & SF_OFS)
462 sbi->s_data_blksize -= 24;
463
464 /* Keep super block in cache */
465 sbi->s_root_bh = root_bh;
466 /* N.B. after this point s_root_bh must be released */
467
468 tmp_flags = sb->s_flags;
469 if (affs_init_bitmap(sb, &tmp_flags))
470 goto out_error;
471 sb->s_flags = tmp_flags;
472
473 /* set up enough so that it can read an inode */
474
475 root_inode = affs_iget(sb, root_block);
476 if (IS_ERR(root_inode)) {
477 ret = PTR_ERR(root_inode);
478 goto out_error_noinode;
479 }
480
481 sb->s_root = d_alloc_root(root_inode);
482 if (!sb->s_root) {
483 printk(KERN_ERR "AFFS: Get root inode failed\n");
484 goto out_error;
485 }
486 sb->s_root->d_op = &affs_dentry_operations;
487
488 pr_debug("AFFS: s_flags=%lX\n",sb->s_flags);
489 return 0;
490
491 /*
492 * Begin the cascaded cleanup ...
493 */
494 out_error:
495 if (root_inode)
496 iput(root_inode);
497 out_error_noinode:
498 kfree(sbi->s_bitmap);
499 affs_brelse(root_bh);
500 kfree(sbi->s_prefix);
501 kfree(sbi);
502 sb->s_fs_info = NULL;
503 return ret;
504 }
505
506 static int
507 affs_remount(struct super_block *sb, int *flags, char *data)
508 {
509 struct affs_sb_info *sbi = AFFS_SB(sb);
510 int blocksize;
511 uid_t uid;
512 gid_t gid;
513 int mode;
514 int reserved;
515 int root_block;
516 unsigned long mount_flags;
517 int res = 0;
518 char *new_opts = kstrdup(data, GFP_KERNEL);
519
520 pr_debug("AFFS: remount(flags=0x%x,opts=\"%s\")\n",*flags,data);
521
522 *flags |= MS_NODIRATIME;
523
524 if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
525 &blocksize, &sbi->s_prefix, sbi->s_volume,
526 &mount_flags)) {
527 kfree(new_opts);
528 return -EINVAL;
529 }
530 lock_kernel();
531 replace_mount_options(sb, new_opts);
532
533 sbi->s_flags = mount_flags;
534 sbi->s_mode = mode;
535 sbi->s_uid = uid;
536 sbi->s_gid = gid;
537
538 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
539 unlock_kernel();
540 return 0;
541 }
542 if (*flags & MS_RDONLY) {
543 sb->s_dirt = 1;
544 while (sb->s_dirt)
545 affs_write_super(sb);
546 affs_free_bitmap(sb);
547 } else
548 res = affs_init_bitmap(sb, flags);
549
550 unlock_kernel();
551 return res;
552 }
553
554 static int
555 affs_statfs(struct dentry *dentry, struct kstatfs *buf)
556 {
557 struct super_block *sb = dentry->d_sb;
558 int free;
559 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
560
561 pr_debug("AFFS: statfs() partsize=%d, reserved=%d\n",AFFS_SB(sb)->s_partition_size,
562 AFFS_SB(sb)->s_reserved);
563
564 free = affs_count_free_blocks(sb);
565 buf->f_type = AFFS_SUPER_MAGIC;
566 buf->f_bsize = sb->s_blocksize;
567 buf->f_blocks = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
568 buf->f_bfree = free;
569 buf->f_bavail = free;
570 buf->f_fsid.val[0] = (u32)id;
571 buf->f_fsid.val[1] = (u32)(id >> 32);
572 buf->f_namelen = 30;
573 return 0;
574 }
575
576 static int affs_get_sb(struct file_system_type *fs_type,
577 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
578 {
579 return get_sb_bdev(fs_type, flags, dev_name, data, affs_fill_super,
580 mnt);
581 }
582
583 static struct file_system_type affs_fs_type = {
584 .owner = THIS_MODULE,
585 .name = "affs",
586 .get_sb = affs_get_sb,
587 .kill_sb = kill_block_super,
588 .fs_flags = FS_REQUIRES_DEV,
589 };
590
591 static int __init init_affs_fs(void)
592 {
593 int err = init_inodecache();
594 if (err)
595 goto out1;
596 err = register_filesystem(&affs_fs_type);
597 if (err)
598 goto out;
599 return 0;
600 out:
601 destroy_inodecache();
602 out1:
603 return err;
604 }
605
606 static void __exit exit_affs_fs(void)
607 {
608 unregister_filesystem(&affs_fs_type);
609 destroy_inodecache();
610 }
611
612 MODULE_DESCRIPTION("Amiga filesystem support for Linux");
613 MODULE_LICENSE("GPL");
614
615 module_init(init_affs_fs)
616 module_exit(exit_affs_fs)
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