xref: /openbmc/linux/fs/adfs/super.c (revision b6dcefde)
1 /*
2  *  linux/fs/adfs/super.c
3  *
4  *  Copyright (C) 1997-1999 Russell King
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/buffer_head.h>
13 #include <linux/parser.h>
14 #include <linux/mount.h>
15 #include <linux/seq_file.h>
16 #include <linux/smp_lock.h>
17 #include <linux/statfs.h>
18 #include "adfs.h"
19 #include "dir_f.h"
20 #include "dir_fplus.h"
21 
22 #define ADFS_DEFAULT_OWNER_MASK S_IRWXU
23 #define ADFS_DEFAULT_OTHER_MASK (S_IRWXG | S_IRWXO)
24 
25 void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
26 {
27 	char error_buf[128];
28 	va_list args;
29 
30 	va_start(args, fmt);
31 	vsnprintf(error_buf, sizeof(error_buf), fmt, args);
32 	va_end(args);
33 
34 	printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %s\n",
35 		sb->s_id, function ? ": " : "",
36 		function ? function : "", error_buf);
37 }
38 
39 static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
40 {
41 	int i;
42 
43 	/* sector size must be 256, 512 or 1024 bytes */
44 	if (dr->log2secsize != 8 &&
45 	    dr->log2secsize != 9 &&
46 	    dr->log2secsize != 10)
47 		return 1;
48 
49 	/* idlen must be at least log2secsize + 3 */
50 	if (dr->idlen < dr->log2secsize + 3)
51 		return 1;
52 
53 	/* we cannot have such a large disc that we
54 	 * are unable to represent sector offsets in
55 	 * 32 bits.  This works out at 2.0 TB.
56 	 */
57 	if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
58 		return 1;
59 
60 	/* idlen must be no greater than 19 v2 [1.0] */
61 	if (dr->idlen > 19)
62 		return 1;
63 
64 	/* reserved bytes should be zero */
65 	for (i = 0; i < sizeof(dr->unused52); i++)
66 		if (dr->unused52[i] != 0)
67 			return 1;
68 
69 	return 0;
70 }
71 
72 static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
73 {
74 	unsigned int v0, v1, v2, v3;
75 	int i;
76 
77 	v0 = v1 = v2 = v3 = 0;
78 	for (i = sb->s_blocksize - 4; i; i -= 4) {
79 		v0 += map[i]     + (v3 >> 8);
80 		v3 &= 0xff;
81 		v1 += map[i + 1] + (v0 >> 8);
82 		v0 &= 0xff;
83 		v2 += map[i + 2] + (v1 >> 8);
84 		v1 &= 0xff;
85 		v3 += map[i + 3] + (v2 >> 8);
86 		v2 &= 0xff;
87 	}
88 	v0 +=           v3 >> 8;
89 	v1 += map[1] + (v0 >> 8);
90 	v2 += map[2] + (v1 >> 8);
91 	v3 += map[3] + (v2 >> 8);
92 
93 	return v0 ^ v1 ^ v2 ^ v3;
94 }
95 
96 static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
97 {
98 	unsigned char crosscheck = 0, zonecheck = 1;
99 	int i;
100 
101 	for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
102 		unsigned char *map;
103 
104 		map = dm[i].dm_bh->b_data;
105 
106 		if (adfs_calczonecheck(sb, map) != map[0]) {
107 			adfs_error(sb, "zone %d fails zonecheck", i);
108 			zonecheck = 0;
109 		}
110 		crosscheck ^= map[3];
111 	}
112 	if (crosscheck != 0xff)
113 		adfs_error(sb, "crosscheck != 0xff");
114 	return crosscheck == 0xff && zonecheck;
115 }
116 
117 static void adfs_put_super(struct super_block *sb)
118 {
119 	int i;
120 	struct adfs_sb_info *asb = ADFS_SB(sb);
121 
122 	lock_kernel();
123 
124 	for (i = 0; i < asb->s_map_size; i++)
125 		brelse(asb->s_map[i].dm_bh);
126 	kfree(asb->s_map);
127 	kfree(asb);
128 	sb->s_fs_info = NULL;
129 
130 	unlock_kernel();
131 }
132 
133 static int adfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
134 {
135 	struct adfs_sb_info *asb = ADFS_SB(mnt->mnt_sb);
136 
137 	if (asb->s_uid != 0)
138 		seq_printf(seq, ",uid=%u", asb->s_uid);
139 	if (asb->s_gid != 0)
140 		seq_printf(seq, ",gid=%u", asb->s_gid);
141 	if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
142 		seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
143 	if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
144 		seq_printf(seq, ",othmask=%o", asb->s_other_mask);
145 
146 	return 0;
147 }
148 
149 enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_err};
150 
151 static const match_table_t tokens = {
152 	{Opt_uid, "uid=%u"},
153 	{Opt_gid, "gid=%u"},
154 	{Opt_ownmask, "ownmask=%o"},
155 	{Opt_othmask, "othmask=%o"},
156 	{Opt_err, NULL}
157 };
158 
159 static int parse_options(struct super_block *sb, char *options)
160 {
161 	char *p;
162 	struct adfs_sb_info *asb = ADFS_SB(sb);
163 	int option;
164 
165 	if (!options)
166 		return 0;
167 
168 	while ((p = strsep(&options, ",")) != NULL) {
169 		substring_t args[MAX_OPT_ARGS];
170 		int token;
171 		if (!*p)
172 			continue;
173 
174 		token = match_token(p, tokens, args);
175 		switch (token) {
176 		case Opt_uid:
177 			if (match_int(args, &option))
178 				return -EINVAL;
179 			asb->s_uid = option;
180 			break;
181 		case Opt_gid:
182 			if (match_int(args, &option))
183 				return -EINVAL;
184 			asb->s_gid = option;
185 			break;
186 		case Opt_ownmask:
187 			if (match_octal(args, &option))
188 				return -EINVAL;
189 			asb->s_owner_mask = option;
190 			break;
191 		case Opt_othmask:
192 			if (match_octal(args, &option))
193 				return -EINVAL;
194 			asb->s_other_mask = option;
195 			break;
196 		default:
197 			printk("ADFS-fs: unrecognised mount option \"%s\" "
198 					"or missing value\n", p);
199 			return -EINVAL;
200 		}
201 	}
202 	return 0;
203 }
204 
205 static int adfs_remount(struct super_block *sb, int *flags, char *data)
206 {
207 	*flags |= MS_NODIRATIME;
208 	return parse_options(sb, data);
209 }
210 
211 static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
212 {
213 	struct super_block *sb = dentry->d_sb;
214 	struct adfs_sb_info *sbi = ADFS_SB(sb);
215 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
216 
217 	buf->f_type    = ADFS_SUPER_MAGIC;
218 	buf->f_namelen = sbi->s_namelen;
219 	buf->f_bsize   = sb->s_blocksize;
220 	buf->f_blocks  = sbi->s_size;
221 	buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;
222 	buf->f_bavail  =
223 	buf->f_bfree   = adfs_map_free(sb);
224 	buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
225 	buf->f_fsid.val[0] = (u32)id;
226 	buf->f_fsid.val[1] = (u32)(id >> 32);
227 
228 	return 0;
229 }
230 
231 static struct kmem_cache *adfs_inode_cachep;
232 
233 static struct inode *adfs_alloc_inode(struct super_block *sb)
234 {
235 	struct adfs_inode_info *ei;
236 	ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
237 	if (!ei)
238 		return NULL;
239 	return &ei->vfs_inode;
240 }
241 
242 static void adfs_destroy_inode(struct inode *inode)
243 {
244 	kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
245 }
246 
247 static void init_once(void *foo)
248 {
249 	struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
250 
251 	inode_init_once(&ei->vfs_inode);
252 }
253 
254 static int init_inodecache(void)
255 {
256 	adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
257 					     sizeof(struct adfs_inode_info),
258 					     0, (SLAB_RECLAIM_ACCOUNT|
259 						SLAB_MEM_SPREAD),
260 					     init_once);
261 	if (adfs_inode_cachep == NULL)
262 		return -ENOMEM;
263 	return 0;
264 }
265 
266 static void destroy_inodecache(void)
267 {
268 	kmem_cache_destroy(adfs_inode_cachep);
269 }
270 
271 static const struct super_operations adfs_sops = {
272 	.alloc_inode	= adfs_alloc_inode,
273 	.destroy_inode	= adfs_destroy_inode,
274 	.write_inode	= adfs_write_inode,
275 	.put_super	= adfs_put_super,
276 	.statfs		= adfs_statfs,
277 	.remount_fs	= adfs_remount,
278 	.show_options	= adfs_show_options,
279 };
280 
281 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
282 {
283 	struct adfs_discmap *dm;
284 	unsigned int map_addr, zone_size, nzones;
285 	int i, zone;
286 	struct adfs_sb_info *asb = ADFS_SB(sb);
287 
288 	nzones    = asb->s_map_size;
289 	zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
290 	map_addr  = (nzones >> 1) * zone_size -
291 		     ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
292 	map_addr  = signed_asl(map_addr, asb->s_map2blk);
293 
294 	asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
295 
296 	dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
297 	if (dm == NULL) {
298 		adfs_error(sb, "not enough memory");
299 		return NULL;
300 	}
301 
302 	for (zone = 0; zone < nzones; zone++, map_addr++) {
303 		dm[zone].dm_startbit = 0;
304 		dm[zone].dm_endbit   = zone_size;
305 		dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
306 		dm[zone].dm_bh       = sb_bread(sb, map_addr);
307 
308 		if (!dm[zone].dm_bh) {
309 			adfs_error(sb, "unable to read map");
310 			goto error_free;
311 		}
312 	}
313 
314 	/* adjust the limits for the first and last map zones */
315 	i = zone - 1;
316 	dm[0].dm_startblk = 0;
317 	dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
318 	dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
319 			    (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
320 			    (ADFS_DR_SIZE_BITS - i * zone_size);
321 
322 	if (adfs_checkmap(sb, dm))
323 		return dm;
324 
325 	adfs_error(sb, "map corrupted");
326 
327 error_free:
328 	while (--zone >= 0)
329 		brelse(dm[zone].dm_bh);
330 
331 	kfree(dm);
332 	return NULL;
333 }
334 
335 static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
336 {
337 	unsigned long discsize;
338 
339 	discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
340 	discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
341 
342 	return discsize;
343 }
344 
345 static int adfs_fill_super(struct super_block *sb, void *data, int silent)
346 {
347 	struct adfs_discrecord *dr;
348 	struct buffer_head *bh;
349 	struct object_info root_obj;
350 	unsigned char *b_data;
351 	struct adfs_sb_info *asb;
352 	struct inode *root;
353 
354 	sb->s_flags |= MS_NODIRATIME;
355 
356 	asb = kzalloc(sizeof(*asb), GFP_KERNEL);
357 	if (!asb)
358 		return -ENOMEM;
359 	sb->s_fs_info = asb;
360 
361 	/* set default options */
362 	asb->s_uid = 0;
363 	asb->s_gid = 0;
364 	asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
365 	asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
366 
367 	if (parse_options(sb, data))
368 		goto error;
369 
370 	sb_set_blocksize(sb, BLOCK_SIZE);
371 	if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
372 		adfs_error(sb, "unable to read superblock");
373 		goto error;
374 	}
375 
376 	b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
377 
378 	if (adfs_checkbblk(b_data)) {
379 		if (!silent)
380 			printk("VFS: Can't find an adfs filesystem on dev "
381 				"%s.\n", sb->s_id);
382 		goto error_free_bh;
383 	}
384 
385 	dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
386 
387 	/*
388 	 * Do some sanity checks on the ADFS disc record
389 	 */
390 	if (adfs_checkdiscrecord(dr)) {
391 		if (!silent)
392 			printk("VPS: Can't find an adfs filesystem on dev "
393 				"%s.\n", sb->s_id);
394 		goto error_free_bh;
395 	}
396 
397 	brelse(bh);
398 	if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
399 		bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
400 		if (!bh) {
401 			adfs_error(sb, "couldn't read superblock on "
402 				"2nd try.");
403 			goto error;
404 		}
405 		b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
406 		if (adfs_checkbblk(b_data)) {
407 			adfs_error(sb, "disc record mismatch, very weird!");
408 			goto error_free_bh;
409 		}
410 		dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
411 	} else {
412 		if (!silent)
413 			printk(KERN_ERR "VFS: Unsupported blocksize on dev "
414 				"%s.\n", sb->s_id);
415 		goto error;
416 	}
417 
418 	/*
419 	 * blocksize on this device should now be set to the ADFS log2secsize
420 	 */
421 
422 	sb->s_magic		= ADFS_SUPER_MAGIC;
423 	asb->s_idlen		= dr->idlen;
424 	asb->s_map_size		= dr->nzones | (dr->nzones_high << 8);
425 	asb->s_map2blk		= dr->log2bpmb - dr->log2secsize;
426 	asb->s_size    		= adfs_discsize(dr, sb->s_blocksize_bits);
427 	asb->s_version 		= dr->format_version;
428 	asb->s_log2sharesize	= dr->log2sharesize;
429 
430 	asb->s_map = adfs_read_map(sb, dr);
431 	if (!asb->s_map)
432 		goto error_free_bh;
433 
434 	brelse(bh);
435 
436 	/*
437 	 * set up enough so that we can read an inode
438 	 */
439 	sb->s_op = &adfs_sops;
440 
441 	dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
442 
443 	root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
444 	root_obj.name_len  = 0;
445 	root_obj.loadaddr  = 0;
446 	root_obj.execaddr  = 0;
447 	root_obj.size	   = ADFS_NEWDIR_SIZE;
448 	root_obj.attr	   = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
449 			     ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
450 
451 	/*
452 	 * If this is a F+ disk with variable length directories,
453 	 * get the root_size from the disc record.
454 	 */
455 	if (asb->s_version) {
456 		root_obj.size = le32_to_cpu(dr->root_size);
457 		asb->s_dir     = &adfs_fplus_dir_ops;
458 		asb->s_namelen = ADFS_FPLUS_NAME_LEN;
459 	} else {
460 		asb->s_dir     = &adfs_f_dir_ops;
461 		asb->s_namelen = ADFS_F_NAME_LEN;
462 	}
463 
464 	root = adfs_iget(sb, &root_obj);
465 	sb->s_root = d_alloc_root(root);
466 	if (!sb->s_root) {
467 		int i;
468 		iput(root);
469 		for (i = 0; i < asb->s_map_size; i++)
470 			brelse(asb->s_map[i].dm_bh);
471 		kfree(asb->s_map);
472 		adfs_error(sb, "get root inode failed\n");
473 		goto error;
474 	} else
475 		sb->s_root->d_op = &adfs_dentry_operations;
476 	return 0;
477 
478 error_free_bh:
479 	brelse(bh);
480 error:
481 	sb->s_fs_info = NULL;
482 	kfree(asb);
483 	return -EINVAL;
484 }
485 
486 static int adfs_get_sb(struct file_system_type *fs_type,
487 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
488 {
489 	return get_sb_bdev(fs_type, flags, dev_name, data, adfs_fill_super,
490 			   mnt);
491 }
492 
493 static struct file_system_type adfs_fs_type = {
494 	.owner		= THIS_MODULE,
495 	.name		= "adfs",
496 	.get_sb		= adfs_get_sb,
497 	.kill_sb	= kill_block_super,
498 	.fs_flags	= FS_REQUIRES_DEV,
499 };
500 
501 static int __init init_adfs_fs(void)
502 {
503 	int err = init_inodecache();
504 	if (err)
505 		goto out1;
506 	err = register_filesystem(&adfs_fs_type);
507 	if (err)
508 		goto out;
509 	return 0;
510 out:
511 	destroy_inodecache();
512 out1:
513 	return err;
514 }
515 
516 static void __exit exit_adfs_fs(void)
517 {
518 	unregister_filesystem(&adfs_fs_type);
519 	destroy_inodecache();
520 }
521 
522 module_init(init_adfs_fs)
523 module_exit(exit_adfs_fs)
524 MODULE_LICENSE("GPL");
525