xref: /openbmc/linux/fs/affs/super.c (revision 84d517f3)
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/slab.h>
20 #include <linux/writeback.h>
21 #include "affs.h"
22 
23 extern struct timezone sys_tz;
24 
25 static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
26 static int affs_remount (struct super_block *sb, int *flags, char *data);
27 
28 static void
29 affs_commit_super(struct super_block *sb, int wait)
30 {
31 	struct affs_sb_info *sbi = AFFS_SB(sb);
32 	struct buffer_head *bh = sbi->s_root_bh;
33 	struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);
34 
35 	lock_buffer(bh);
36 	secs_to_datestamp(get_seconds(), &tail->disk_change);
37 	affs_fix_checksum(sb, bh);
38 	unlock_buffer(bh);
39 
40 	mark_buffer_dirty(bh);
41 	if (wait)
42 		sync_dirty_buffer(bh);
43 }
44 
45 static void
46 affs_put_super(struct super_block *sb)
47 {
48 	struct affs_sb_info *sbi = AFFS_SB(sb);
49 	pr_debug("AFFS: put_super()\n");
50 
51 	cancel_delayed_work_sync(&sbi->sb_work);
52 }
53 
54 static int
55 affs_sync_fs(struct super_block *sb, int wait)
56 {
57 	affs_commit_super(sb, wait);
58 	return 0;
59 }
60 
61 static void flush_superblock(struct work_struct *work)
62 {
63 	struct affs_sb_info *sbi;
64 	struct super_block *sb;
65 
66 	sbi = container_of(work, struct affs_sb_info, sb_work.work);
67 	sb = sbi->sb;
68 
69 	spin_lock(&sbi->work_lock);
70 	sbi->work_queued = 0;
71 	spin_unlock(&sbi->work_lock);
72 
73 	affs_commit_super(sb, 1);
74 }
75 
76 void affs_mark_sb_dirty(struct super_block *sb)
77 {
78 	struct affs_sb_info *sbi = AFFS_SB(sb);
79 	unsigned long delay;
80 
81 	if (sb->s_flags & MS_RDONLY)
82 	       return;
83 
84 	spin_lock(&sbi->work_lock);
85 	if (!sbi->work_queued) {
86 	       delay = msecs_to_jiffies(dirty_writeback_interval * 10);
87 	       queue_delayed_work(system_long_wq, &sbi->sb_work, delay);
88 	       sbi->work_queued = 1;
89 	}
90 	spin_unlock(&sbi->work_lock);
91 }
92 
93 static struct kmem_cache * affs_inode_cachep;
94 
95 static struct inode *affs_alloc_inode(struct super_block *sb)
96 {
97 	struct affs_inode_info *i;
98 
99 	i = kmem_cache_alloc(affs_inode_cachep, GFP_KERNEL);
100 	if (!i)
101 		return NULL;
102 
103 	i->vfs_inode.i_version = 1;
104 	i->i_lc = NULL;
105 	i->i_ext_bh = NULL;
106 	i->i_pa_cnt = 0;
107 
108 	return &i->vfs_inode;
109 }
110 
111 static void affs_i_callback(struct rcu_head *head)
112 {
113 	struct inode *inode = container_of(head, struct inode, i_rcu);
114 	kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
115 }
116 
117 static void affs_destroy_inode(struct inode *inode)
118 {
119 	call_rcu(&inode->i_rcu, affs_i_callback);
120 }
121 
122 static void init_once(void *foo)
123 {
124 	struct affs_inode_info *ei = (struct affs_inode_info *) foo;
125 
126 	sema_init(&ei->i_link_lock, 1);
127 	sema_init(&ei->i_ext_lock, 1);
128 	inode_init_once(&ei->vfs_inode);
129 }
130 
131 static int __init init_inodecache(void)
132 {
133 	affs_inode_cachep = kmem_cache_create("affs_inode_cache",
134 					     sizeof(struct affs_inode_info),
135 					     0, (SLAB_RECLAIM_ACCOUNT|
136 						SLAB_MEM_SPREAD),
137 					     init_once);
138 	if (affs_inode_cachep == NULL)
139 		return -ENOMEM;
140 	return 0;
141 }
142 
143 static void destroy_inodecache(void)
144 {
145 	/*
146 	 * Make sure all delayed rcu free inodes are flushed before we
147 	 * destroy cache.
148 	 */
149 	rcu_barrier();
150 	kmem_cache_destroy(affs_inode_cachep);
151 }
152 
153 static const struct super_operations affs_sops = {
154 	.alloc_inode	= affs_alloc_inode,
155 	.destroy_inode	= affs_destroy_inode,
156 	.write_inode	= affs_write_inode,
157 	.evict_inode	= affs_evict_inode,
158 	.put_super	= affs_put_super,
159 	.sync_fs	= affs_sync_fs,
160 	.statfs		= affs_statfs,
161 	.remount_fs	= affs_remount,
162 	.show_options	= generic_show_options,
163 };
164 
165 enum {
166 	Opt_bs, Opt_mode, Opt_mufs, Opt_notruncate, Opt_prefix, Opt_protect,
167 	Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
168 	Opt_verbose, Opt_volume, Opt_ignore, Opt_err,
169 };
170 
171 static const match_table_t tokens = {
172 	{Opt_bs, "bs=%u"},
173 	{Opt_mode, "mode=%o"},
174 	{Opt_mufs, "mufs"},
175 	{Opt_notruncate, "nofilenametruncate"},
176 	{Opt_prefix, "prefix=%s"},
177 	{Opt_protect, "protect"},
178 	{Opt_reserved, "reserved=%u"},
179 	{Opt_root, "root=%u"},
180 	{Opt_setgid, "setgid=%u"},
181 	{Opt_setuid, "setuid=%u"},
182 	{Opt_verbose, "verbose"},
183 	{Opt_volume, "volume=%s"},
184 	{Opt_ignore, "grpquota"},
185 	{Opt_ignore, "noquota"},
186 	{Opt_ignore, "quota"},
187 	{Opt_ignore, "usrquota"},
188 	{Opt_err, NULL},
189 };
190 
191 static int
192 parse_options(char *options, kuid_t *uid, kgid_t *gid, int *mode, int *reserved, s32 *root,
193 		int *blocksize, char **prefix, char *volume, unsigned long *mount_opts)
194 {
195 	char *p;
196 	substring_t args[MAX_OPT_ARGS];
197 
198 	/* Fill in defaults */
199 
200 	*uid        = current_uid();
201 	*gid        = current_gid();
202 	*reserved   = 2;
203 	*root       = -1;
204 	*blocksize  = -1;
205 	volume[0]   = ':';
206 	volume[1]   = 0;
207 	*mount_opts = 0;
208 	if (!options)
209 		return 1;
210 
211 	while ((p = strsep(&options, ",")) != NULL) {
212 		int token, n, option;
213 		if (!*p)
214 			continue;
215 
216 		token = match_token(p, tokens, args);
217 		switch (token) {
218 		case Opt_bs:
219 			if (match_int(&args[0], &n))
220 				return 0;
221 			if (n != 512 && n != 1024 && n != 2048
222 			    && n != 4096) {
223 				printk ("AFFS: Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
224 				return 0;
225 			}
226 			*blocksize = n;
227 			break;
228 		case Opt_mode:
229 			if (match_octal(&args[0], &option))
230 				return 0;
231 			*mode = option & 0777;
232 			*mount_opts |= SF_SETMODE;
233 			break;
234 		case Opt_mufs:
235 			*mount_opts |= SF_MUFS;
236 			break;
237 		case Opt_notruncate:
238 			*mount_opts |= SF_NO_TRUNCATE;
239 			break;
240 		case Opt_prefix:
241 			*prefix = match_strdup(&args[0]);
242 			if (!*prefix)
243 				return 0;
244 			*mount_opts |= SF_PREFIX;
245 			break;
246 		case Opt_protect:
247 			*mount_opts |= SF_IMMUTABLE;
248 			break;
249 		case Opt_reserved:
250 			if (match_int(&args[0], reserved))
251 				return 0;
252 			break;
253 		case Opt_root:
254 			if (match_int(&args[0], root))
255 				return 0;
256 			break;
257 		case Opt_setgid:
258 			if (match_int(&args[0], &option))
259 				return 0;
260 			*gid = make_kgid(current_user_ns(), option);
261 			if (!gid_valid(*gid))
262 				return 0;
263 			*mount_opts |= SF_SETGID;
264 			break;
265 		case Opt_setuid:
266 			if (match_int(&args[0], &option))
267 				return 0;
268 			*uid = make_kuid(current_user_ns(), option);
269 			if (!uid_valid(*uid))
270 				return 0;
271 			*mount_opts |= SF_SETUID;
272 			break;
273 		case Opt_verbose:
274 			*mount_opts |= SF_VERBOSE;
275 			break;
276 		case Opt_volume: {
277 			char *vol = match_strdup(&args[0]);
278 			if (!vol)
279 				return 0;
280 			strlcpy(volume, vol, 32);
281 			kfree(vol);
282 			break;
283 		}
284 		case Opt_ignore:
285 		 	/* Silently ignore the quota options */
286 			break;
287 		default:
288 			printk("AFFS: Unrecognized mount option \"%s\" "
289 					"or missing value\n", p);
290 			return 0;
291 		}
292 	}
293 	return 1;
294 }
295 
296 /* This function definitely needs to be split up. Some fine day I'll
297  * hopefully have the guts to do so. Until then: sorry for the mess.
298  */
299 
300 static int affs_fill_super(struct super_block *sb, void *data, int silent)
301 {
302 	struct affs_sb_info	*sbi;
303 	struct buffer_head	*root_bh = NULL;
304 	struct buffer_head	*boot_bh;
305 	struct inode		*root_inode = NULL;
306 	s32			 root_block;
307 	int			 size, blocksize;
308 	u32			 chksum;
309 	int			 num_bm;
310 	int			 i, j;
311 	s32			 key;
312 	kuid_t			 uid;
313 	kgid_t			 gid;
314 	int			 reserved;
315 	unsigned long		 mount_flags;
316 	int			 tmp_flags;	/* fix remount prototype... */
317 	u8			 sig[4];
318 	int			 ret;
319 
320 	save_mount_options(sb, data);
321 
322 	pr_debug("AFFS: read_super(%s)\n",data ? (const char *)data : "no options");
323 
324 	sb->s_magic             = AFFS_SUPER_MAGIC;
325 	sb->s_op                = &affs_sops;
326 	sb->s_flags |= MS_NODIRATIME;
327 
328 	sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
329 	if (!sbi)
330 		return -ENOMEM;
331 
332 	sb->s_fs_info = sbi;
333 	sbi->sb = sb;
334 	mutex_init(&sbi->s_bmlock);
335 	spin_lock_init(&sbi->symlink_lock);
336 	spin_lock_init(&sbi->work_lock);
337 	INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);
338 
339 	if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
340 				&blocksize,&sbi->s_prefix,
341 				sbi->s_volume, &mount_flags)) {
342 		printk(KERN_ERR "AFFS: Error parsing options\n");
343 		return -EINVAL;
344 	}
345 	/* N.B. after this point s_prefix must be released */
346 
347 	sbi->s_flags   = mount_flags;
348 	sbi->s_mode    = i;
349 	sbi->s_uid     = uid;
350 	sbi->s_gid     = gid;
351 	sbi->s_reserved= reserved;
352 
353 	/* Get the size of the device in 512-byte blocks.
354 	 * If we later see that the partition uses bigger
355 	 * blocks, we will have to change it.
356 	 */
357 
358 	size = sb->s_bdev->bd_inode->i_size >> 9;
359 	pr_debug("AFFS: initial blocksize=%d, #blocks=%d\n", 512, size);
360 
361 	affs_set_blocksize(sb, PAGE_SIZE);
362 	/* Try to find root block. Its location depends on the block size. */
363 
364 	i = 512;
365 	j = 4096;
366 	if (blocksize > 0) {
367 		i = j = blocksize;
368 		size = size / (blocksize / 512);
369 	}
370 	for (blocksize = i, key = 0; blocksize <= j; blocksize <<= 1, size >>= 1) {
371 		sbi->s_root_block = root_block;
372 		if (root_block < 0)
373 			sbi->s_root_block = (reserved + size - 1) / 2;
374 		pr_debug("AFFS: setting blocksize to %d\n", blocksize);
375 		affs_set_blocksize(sb, blocksize);
376 		sbi->s_partition_size = size;
377 
378 		/* The root block location that was calculated above is not
379 		 * correct if the partition size is an odd number of 512-
380 		 * byte blocks, which will be rounded down to a number of
381 		 * 1024-byte blocks, and if there were an even number of
382 		 * reserved blocks. Ideally, all partition checkers should
383 		 * report the real number of blocks of the real blocksize,
384 		 * but since this just cannot be done, we have to try to
385 		 * find the root block anyways. In the above case, it is one
386 		 * block behind the calculated one. So we check this one, too.
387 		 */
388 		for (num_bm = 0; num_bm < 2; num_bm++) {
389 			pr_debug("AFFS: Dev %s, trying root=%u, bs=%d, "
390 				"size=%d, reserved=%d\n",
391 				sb->s_id,
392 				sbi->s_root_block + num_bm,
393 				blocksize, size, reserved);
394 			root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
395 			if (!root_bh)
396 				continue;
397 			if (!affs_checksum_block(sb, root_bh) &&
398 			    be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
399 			    be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
400 				sbi->s_hashsize    = blocksize / 4 - 56;
401 				sbi->s_root_block += num_bm;
402 				key                        = 1;
403 				goto got_root;
404 			}
405 			affs_brelse(root_bh);
406 			root_bh = NULL;
407 		}
408 	}
409 	if (!silent)
410 		printk(KERN_ERR "AFFS: No valid root block on device %s\n",
411 			sb->s_id);
412 	return -EINVAL;
413 
414 	/* N.B. after this point bh must be released */
415 got_root:
416 	/* Keep super block in cache */
417 	sbi->s_root_bh = root_bh;
418 	root_block = sbi->s_root_block;
419 
420 	/* Find out which kind of FS we have */
421 	boot_bh = sb_bread(sb, 0);
422 	if (!boot_bh) {
423 		printk(KERN_ERR "AFFS: Cannot read boot block\n");
424 		return -EINVAL;
425 	}
426 	memcpy(sig, boot_bh->b_data, 4);
427 	brelse(boot_bh);
428 	chksum = be32_to_cpu(*(__be32 *)sig);
429 
430 	/* Dircache filesystems are compatible with non-dircache ones
431 	 * when reading. As long as they aren't supported, writing is
432 	 * not recommended.
433 	 */
434 	if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
435 	     || chksum == MUFS_DCOFS) && !(sb->s_flags & MS_RDONLY)) {
436 		printk(KERN_NOTICE "AFFS: Dircache FS - mounting %s read only\n",
437 			sb->s_id);
438 		sb->s_flags |= MS_RDONLY;
439 	}
440 	switch (chksum) {
441 		case MUFS_FS:
442 		case MUFS_INTLFFS:
443 		case MUFS_DCFFS:
444 			sbi->s_flags |= SF_MUFS;
445 			/* fall thru */
446 		case FS_INTLFFS:
447 		case FS_DCFFS:
448 			sbi->s_flags |= SF_INTL;
449 			break;
450 		case MUFS_FFS:
451 			sbi->s_flags |= SF_MUFS;
452 			break;
453 		case FS_FFS:
454 			break;
455 		case MUFS_OFS:
456 			sbi->s_flags |= SF_MUFS;
457 			/* fall thru */
458 		case FS_OFS:
459 			sbi->s_flags |= SF_OFS;
460 			sb->s_flags |= MS_NOEXEC;
461 			break;
462 		case MUFS_DCOFS:
463 		case MUFS_INTLOFS:
464 			sbi->s_flags |= SF_MUFS;
465 		case FS_DCOFS:
466 		case FS_INTLOFS:
467 			sbi->s_flags |= SF_INTL | SF_OFS;
468 			sb->s_flags |= MS_NOEXEC;
469 			break;
470 		default:
471 			printk(KERN_ERR "AFFS: Unknown filesystem on device %s: %08X\n",
472 				sb->s_id, chksum);
473 			return -EINVAL;
474 	}
475 
476 	if (mount_flags & SF_VERBOSE) {
477 		u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
478 		printk(KERN_NOTICE "AFFS: Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
479 			len > 31 ? 31 : len,
480 			AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
481 			sig, sig[3] + '0', blocksize);
482 	}
483 
484 	sb->s_flags |= MS_NODEV | MS_NOSUID;
485 
486 	sbi->s_data_blksize = sb->s_blocksize;
487 	if (sbi->s_flags & SF_OFS)
488 		sbi->s_data_blksize -= 24;
489 
490 	tmp_flags = sb->s_flags;
491 	ret = affs_init_bitmap(sb, &tmp_flags);
492 	if (ret)
493 		return ret;
494 	sb->s_flags = tmp_flags;
495 
496 	/* set up enough so that it can read an inode */
497 
498 	root_inode = affs_iget(sb, root_block);
499 	if (IS_ERR(root_inode))
500 		return PTR_ERR(root_inode);
501 
502 	if (AFFS_SB(sb)->s_flags & SF_INTL)
503 		sb->s_d_op = &affs_intl_dentry_operations;
504 	else
505 		sb->s_d_op = &affs_dentry_operations;
506 
507 	sb->s_root = d_make_root(root_inode);
508 	if (!sb->s_root) {
509 		printk(KERN_ERR "AFFS: Get root inode failed\n");
510 		return -ENOMEM;
511 	}
512 
513 	pr_debug("AFFS: s_flags=%lX\n",sb->s_flags);
514 	return 0;
515 }
516 
517 static int
518 affs_remount(struct super_block *sb, int *flags, char *data)
519 {
520 	struct affs_sb_info	*sbi = AFFS_SB(sb);
521 	int			 blocksize;
522 	kuid_t			 uid;
523 	kgid_t			 gid;
524 	int			 mode;
525 	int			 reserved;
526 	int			 root_block;
527 	unsigned long		 mount_flags;
528 	int			 res = 0;
529 	char			*new_opts = kstrdup(data, GFP_KERNEL);
530 	char			 volume[32];
531 	char			*prefix = NULL;
532 
533 	pr_debug("AFFS: remount(flags=0x%x,opts=\"%s\")\n",*flags,data);
534 
535 	sync_filesystem(sb);
536 	*flags |= MS_NODIRATIME;
537 
538 	memcpy(volume, sbi->s_volume, 32);
539 	if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
540 			   &blocksize, &prefix, volume,
541 			   &mount_flags)) {
542 		kfree(prefix);
543 		kfree(new_opts);
544 		return -EINVAL;
545 	}
546 
547 	flush_delayed_work(&sbi->sb_work);
548 	replace_mount_options(sb, new_opts);
549 
550 	sbi->s_flags = mount_flags;
551 	sbi->s_mode  = mode;
552 	sbi->s_uid   = uid;
553 	sbi->s_gid   = gid;
554 	/* protect against readers */
555 	spin_lock(&sbi->symlink_lock);
556 	if (prefix) {
557 		kfree(sbi->s_prefix);
558 		sbi->s_prefix = prefix;
559 	}
560 	memcpy(sbi->s_volume, volume, 32);
561 	spin_unlock(&sbi->symlink_lock);
562 
563 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
564 		return 0;
565 
566 	if (*flags & MS_RDONLY)
567 		affs_free_bitmap(sb);
568 	else
569 		res = affs_init_bitmap(sb, flags);
570 
571 	return res;
572 }
573 
574 static int
575 affs_statfs(struct dentry *dentry, struct kstatfs *buf)
576 {
577 	struct super_block *sb = dentry->d_sb;
578 	int		 free;
579 	u64		 id = huge_encode_dev(sb->s_bdev->bd_dev);
580 
581 	pr_debug("AFFS: statfs() partsize=%d, reserved=%d\n",AFFS_SB(sb)->s_partition_size,
582 	     AFFS_SB(sb)->s_reserved);
583 
584 	free          = affs_count_free_blocks(sb);
585 	buf->f_type    = AFFS_SUPER_MAGIC;
586 	buf->f_bsize   = sb->s_blocksize;
587 	buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
588 	buf->f_bfree   = free;
589 	buf->f_bavail  = free;
590 	buf->f_fsid.val[0] = (u32)id;
591 	buf->f_fsid.val[1] = (u32)(id >> 32);
592 	buf->f_namelen = 30;
593 	return 0;
594 }
595 
596 static struct dentry *affs_mount(struct file_system_type *fs_type,
597 	int flags, const char *dev_name, void *data)
598 {
599 	return mount_bdev(fs_type, flags, dev_name, data, affs_fill_super);
600 }
601 
602 static void affs_kill_sb(struct super_block *sb)
603 {
604 	struct affs_sb_info *sbi = AFFS_SB(sb);
605 	kill_block_super(sb);
606 	if (sbi) {
607 		affs_free_bitmap(sb);
608 		affs_brelse(sbi->s_root_bh);
609 		kfree(sbi->s_prefix);
610 		kfree(sbi);
611 	}
612 }
613 
614 static struct file_system_type affs_fs_type = {
615 	.owner		= THIS_MODULE,
616 	.name		= "affs",
617 	.mount		= affs_mount,
618 	.kill_sb	= affs_kill_sb,
619 	.fs_flags	= FS_REQUIRES_DEV,
620 };
621 MODULE_ALIAS_FS("affs");
622 
623 static int __init init_affs_fs(void)
624 {
625 	int err = init_inodecache();
626 	if (err)
627 		goto out1;
628 	err = register_filesystem(&affs_fs_type);
629 	if (err)
630 		goto out;
631 	return 0;
632 out:
633 	destroy_inodecache();
634 out1:
635 	return err;
636 }
637 
638 static void __exit exit_affs_fs(void)
639 {
640 	unregister_filesystem(&affs_fs_type);
641 	destroy_inodecache();
642 }
643 
644 MODULE_DESCRIPTION("Amiga filesystem support for Linux");
645 MODULE_LICENSE("GPL");
646 
647 module_init(init_affs_fs)
648 module_exit(exit_affs_fs)
649