xref: /openbmc/linux/fs/adfs/super.c (revision 1da177e4) 
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/errno.h>
12 #include <linux/fs.h>
13 #include <linux/adfs_fs.h>
14 #include <linux/slab.h>
15 #include <linux/time.h>
16 #include <linux/stat.h>
17 #include <linux/string.h>
18 #include <linux/init.h>
19 #include <linux/buffer_head.h>
20 #include <linux/vfs.h>
21 #include <linux/parser.h>
22 #include <linux/bitops.h>
23 
24 #include <asm/uaccess.h>
25 #include <asm/system.h>
26 
27 #include <stdarg.h>
28 
29 #include "adfs.h"
30 #include "dir_f.h"
31 #include "dir_fplus.h"
32 
33 void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
34 {
35 	char error_buf[128];
36 	va_list args;
37 
38 	va_start(args, fmt);
39 	vsprintf(error_buf, fmt, args);
40 	va_end(args);
41 
42 	printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %s\n",
43 		sb->s_id, function ? ": " : "",
44 		function ? function : "", error_buf);
45 }
46 
47 static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
48 {
49 	int i;
50 
51 	/* sector size must be 256, 512 or 1024 bytes */
52 	if (dr->log2secsize != 8 &&
53 	    dr->log2secsize != 9 &&
54 	    dr->log2secsize != 10)
55 		return 1;
56 
57 	/* idlen must be at least log2secsize + 3 */
58 	if (dr->idlen < dr->log2secsize + 3)
59 		return 1;
60 
61 	/* we cannot have such a large disc that we
62 	 * are unable to represent sector offsets in
63 	 * 32 bits.  This works out at 2.0 TB.
64 	 */
65 	if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
66 		return 1;
67 
68 	/* idlen must be no greater than 19 v2 [1.0] */
69 	if (dr->idlen > 19)
70 		return 1;
71 
72 	/* reserved bytes should be zero */
73 	for (i = 0; i < sizeof(dr->unused52); i++)
74 		if (dr->unused52[i] != 0)
75 			return 1;
76 
77 	return 0;
78 }
79 
80 static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
81 {
82 	unsigned int v0, v1, v2, v3;
83 	int i;
84 
85 	v0 = v1 = v2 = v3 = 0;
86 	for (i = sb->s_blocksize - 4; i; i -= 4) {
87 		v0 += map[i]     + (v3 >> 8);
88 		v3 &= 0xff;
89 		v1 += map[i + 1] + (v0 >> 8);
90 		v0 &= 0xff;
91 		v2 += map[i + 2] + (v1 >> 8);
92 		v1 &= 0xff;
93 		v3 += map[i + 3] + (v2 >> 8);
94 		v2 &= 0xff;
95 	}
96 	v0 +=           v3 >> 8;
97 	v1 += map[1] + (v0 >> 8);
98 	v2 += map[2] + (v1 >> 8);
99 	v3 += map[3] + (v2 >> 8);
100 
101 	return v0 ^ v1 ^ v2 ^ v3;
102 }
103 
104 static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
105 {
106 	unsigned char crosscheck = 0, zonecheck = 1;
107 	int i;
108 
109 	for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
110 		unsigned char *map;
111 
112 		map = dm[i].dm_bh->b_data;
113 
114 		if (adfs_calczonecheck(sb, map) != map[0]) {
115 			adfs_error(sb, "zone %d fails zonecheck", i);
116 			zonecheck = 0;
117 		}
118 		crosscheck ^= map[3];
119 	}
120 	if (crosscheck != 0xff)
121 		adfs_error(sb, "crosscheck != 0xff");
122 	return crosscheck == 0xff && zonecheck;
123 }
124 
125 static void adfs_put_super(struct super_block *sb)
126 {
127 	int i;
128 	struct adfs_sb_info *asb = ADFS_SB(sb);
129 
130 	for (i = 0; i < asb->s_map_size; i++)
131 		brelse(asb->s_map[i].dm_bh);
132 	kfree(asb->s_map);
133 	kfree(asb);
134 	sb->s_fs_info = NULL;
135 }
136 
137 enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_err};
138 
139 static match_table_t tokens = {
140 	{Opt_uid, "uid=%u"},
141 	{Opt_gid, "gid=%u"},
142 	{Opt_ownmask, "ownmask=%o"},
143 	{Opt_othmask, "othmask=%o"},
144 	{Opt_err, NULL}
145 };
146 
147 static int parse_options(struct super_block *sb, char *options)
148 {
149 	char *p;
150 	struct adfs_sb_info *asb = ADFS_SB(sb);
151 	int option;
152 
153 	if (!options)
154 		return 0;
155 
156 	while ((p = strsep(&options, ",")) != NULL) {
157 		substring_t args[MAX_OPT_ARGS];
158 		int token;
159 		if (!*p)
160 			continue;
161 
162 		token = match_token(p, tokens, args);
163 		switch (token) {
164 		case Opt_uid:
165 			if (match_int(args, &option))
166 				return -EINVAL;
167 			asb->s_uid = option;
168 			break;
169 		case Opt_gid:
170 			if (match_int(args, &option))
171 				return -EINVAL;
172 			asb->s_gid = option;
173 			break;
174 		case Opt_ownmask:
175 			if (match_octal(args, &option))
176 				return -EINVAL;
177 			asb->s_owner_mask = option;
178 			break;
179 		case Opt_othmask:
180 			if (match_octal(args, &option))
181 				return -EINVAL;
182 			asb->s_other_mask = option;
183 			break;
184 		default:
185 			printk("ADFS-fs: unrecognised mount option \"%s\" "
186 					"or missing value\n", p);
187 			return -EINVAL;
188 		}
189 	}
190 	return 0;
191 }
192 
193 static int adfs_remount(struct super_block *sb, int *flags, char *data)
194 {
195 	*flags |= MS_NODIRATIME;
196 	return parse_options(sb, data);
197 }
198 
199 static int adfs_statfs(struct super_block *sb, struct kstatfs *buf)
200 {
201 	struct adfs_sb_info *asb = ADFS_SB(sb);
202 
203 	buf->f_type    = ADFS_SUPER_MAGIC;
204 	buf->f_namelen = asb->s_namelen;
205 	buf->f_bsize   = sb->s_blocksize;
206 	buf->f_blocks  = asb->s_size;
207 	buf->f_files   = asb->s_ids_per_zone * asb->s_map_size;
208 	buf->f_bavail  =
209 	buf->f_bfree   = adfs_map_free(sb);
210 	buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
211 
212 	return 0;
213 }
214 
215 static kmem_cache_t *adfs_inode_cachep;
216 
217 static struct inode *adfs_alloc_inode(struct super_block *sb)
218 {
219 	struct adfs_inode_info *ei;
220 	ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, SLAB_KERNEL);
221 	if (!ei)
222 		return NULL;
223 	return &ei->vfs_inode;
224 }
225 
226 static void adfs_destroy_inode(struct inode *inode)
227 {
228 	kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
229 }
230 
231 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
232 {
233 	struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
234 
235 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
236 	    SLAB_CTOR_CONSTRUCTOR)
237 		inode_init_once(&ei->vfs_inode);
238 }
239 
240 static int init_inodecache(void)
241 {
242 	adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
243 					     sizeof(struct adfs_inode_info),
244 					     0, SLAB_RECLAIM_ACCOUNT,
245 					     init_once, NULL);
246 	if (adfs_inode_cachep == NULL)
247 		return -ENOMEM;
248 	return 0;
249 }
250 
251 static void destroy_inodecache(void)
252 {
253 	if (kmem_cache_destroy(adfs_inode_cachep))
254 		printk(KERN_INFO "adfs_inode_cache: not all structures were freed\n");
255 }
256 
257 static struct super_operations adfs_sops = {
258 	.alloc_inode	= adfs_alloc_inode,
259 	.destroy_inode	= adfs_destroy_inode,
260 	.write_inode	= adfs_write_inode,
261 	.put_super	= adfs_put_super,
262 	.statfs		= adfs_statfs,
263 	.remount_fs	= adfs_remount,
264 };
265 
266 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
267 {
268 	struct adfs_discmap *dm;
269 	unsigned int map_addr, zone_size, nzones;
270 	int i, zone;
271 	struct adfs_sb_info *asb = ADFS_SB(sb);
272 
273 	nzones    = asb->s_map_size;
274 	zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
275 	map_addr  = (nzones >> 1) * zone_size -
276 		     ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
277 	map_addr  = signed_asl(map_addr, asb->s_map2blk);
278 
279 	asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
280 
281 	dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
282 	if (dm == NULL) {
283 		adfs_error(sb, "not enough memory");
284 		return NULL;
285 	}
286 
287 	for (zone = 0; zone < nzones; zone++, map_addr++) {
288 		dm[zone].dm_startbit = 0;
289 		dm[zone].dm_endbit   = zone_size;
290 		dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
291 		dm[zone].dm_bh       = sb_bread(sb, map_addr);
292 
293 		if (!dm[zone].dm_bh) {
294 			adfs_error(sb, "unable to read map");
295 			goto error_free;
296 		}
297 	}
298 
299 	/* adjust the limits for the first and last map zones */
300 	i = zone - 1;
301 	dm[0].dm_startblk = 0;
302 	dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
303 	dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
304 			    (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
305 			    (ADFS_DR_SIZE_BITS - i * zone_size);
306 
307 	if (adfs_checkmap(sb, dm))
308 		return dm;
309 
310 	adfs_error(sb, NULL, "map corrupted");
311 
312 error_free:
313 	while (--zone >= 0)
314 		brelse(dm[zone].dm_bh);
315 
316 	kfree(dm);
317 	return NULL;
318 }
319 
320 static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
321 {
322 	unsigned long discsize;
323 
324 	discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
325 	discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
326 
327 	return discsize;
328 }
329 
330 static int adfs_fill_super(struct super_block *sb, void *data, int silent)
331 {
332 	struct adfs_discrecord *dr;
333 	struct buffer_head *bh;
334 	struct object_info root_obj;
335 	unsigned char *b_data;
336 	struct adfs_sb_info *asb;
337 	struct inode *root;
338 
339 	sb->s_flags |= MS_NODIRATIME;
340 
341 	asb = kmalloc(sizeof(*asb), GFP_KERNEL);
342 	if (!asb)
343 		return -ENOMEM;
344 	sb->s_fs_info = asb;
345 	memset(asb, 0, sizeof(*asb));
346 
347 	/* set default options */
348 	asb->s_uid = 0;
349 	asb->s_gid = 0;
350 	asb->s_owner_mask = S_IRWXU;
351 	asb->s_other_mask = S_IRWXG | S_IRWXO;
352 
353 	if (parse_options(sb, data))
354 		goto error;
355 
356 	sb_set_blocksize(sb, BLOCK_SIZE);
357 	if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
358 		adfs_error(sb, "unable to read superblock");
359 		goto error;
360 	}
361 
362 	b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
363 
364 	if (adfs_checkbblk(b_data)) {
365 		if (!silent)
366 			printk("VFS: Can't find an adfs filesystem on dev "
367 				"%s.\n", sb->s_id);
368 		goto error_free_bh;
369 	}
370 
371 	dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
372 
373 	/*
374 	 * Do some sanity checks on the ADFS disc record
375 	 */
376 	if (adfs_checkdiscrecord(dr)) {
377 		if (!silent)
378 			printk("VPS: Can't find an adfs filesystem on dev "
379 				"%s.\n", sb->s_id);
380 		goto error_free_bh;
381 	}
382 
383 	brelse(bh);
384 	if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
385 		bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
386 		if (!bh) {
387 			adfs_error(sb, "couldn't read superblock on "
388 				"2nd try.");
389 			goto error;
390 		}
391 		b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
392 		if (adfs_checkbblk(b_data)) {
393 			adfs_error(sb, "disc record mismatch, very weird!");
394 			goto error_free_bh;
395 		}
396 		dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
397 	} else {
398 		if (!silent)
399 			printk(KERN_ERR "VFS: Unsupported blocksize on dev "
400 				"%s.\n", sb->s_id);
401 		goto error;
402 	}
403 
404 	/*
405 	 * blocksize on this device should now be set to the ADFS log2secsize
406 	 */
407 
408 	sb->s_magic		= ADFS_SUPER_MAGIC;
409 	asb->s_idlen		= dr->idlen;
410 	asb->s_map_size		= dr->nzones | (dr->nzones_high << 8);
411 	asb->s_map2blk		= dr->log2bpmb - dr->log2secsize;
412 	asb->s_size    		= adfs_discsize(dr, sb->s_blocksize_bits);
413 	asb->s_version 		= dr->format_version;
414 	asb->s_log2sharesize	= dr->log2sharesize;
415 
416 	asb->s_map = adfs_read_map(sb, dr);
417 	if (!asb->s_map)
418 		goto error_free_bh;
419 
420 	brelse(bh);
421 
422 	/*
423 	 * set up enough so that we can read an inode
424 	 */
425 	sb->s_op = &adfs_sops;
426 
427 	dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
428 
429 	root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
430 	root_obj.name_len  = 0;
431 	root_obj.loadaddr  = 0;
432 	root_obj.execaddr  = 0;
433 	root_obj.size	   = ADFS_NEWDIR_SIZE;
434 	root_obj.attr	   = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
435 			     ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
436 
437 	/*
438 	 * If this is a F+ disk with variable length directories,
439 	 * get the root_size from the disc record.
440 	 */
441 	if (asb->s_version) {
442 		root_obj.size = le32_to_cpu(dr->root_size);
443 		asb->s_dir     = &adfs_fplus_dir_ops;
444 		asb->s_namelen = ADFS_FPLUS_NAME_LEN;
445 	} else {
446 		asb->s_dir     = &adfs_f_dir_ops;
447 		asb->s_namelen = ADFS_F_NAME_LEN;
448 	}
449 
450 	root = adfs_iget(sb, &root_obj);
451 	sb->s_root = d_alloc_root(root);
452 	if (!sb->s_root) {
453 		int i;
454 		iput(root);
455 		for (i = 0; i < asb->s_map_size; i++)
456 			brelse(asb->s_map[i].dm_bh);
457 		kfree(asb->s_map);
458 		adfs_error(sb, "get root inode failed\n");
459 		goto error;
460 	} else
461 		sb->s_root->d_op = &adfs_dentry_operations;
462 	return 0;
463 
464 error_free_bh:
465 	brelse(bh);
466 error:
467 	sb->s_fs_info = NULL;
468 	kfree(asb);
469 	return -EINVAL;
470 }
471 
472 static struct super_block *adfs_get_sb(struct file_system_type *fs_type,
473 	int flags, const char *dev_name, void *data)
474 {
475 	return get_sb_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
476 }
477 
478 static struct file_system_type adfs_fs_type = {
479 	.owner		= THIS_MODULE,
480 	.name		= "adfs",
481 	.get_sb		= adfs_get_sb,
482 	.kill_sb	= kill_block_super,
483 	.fs_flags	= FS_REQUIRES_DEV,
484 };
485 
486 static int __init init_adfs_fs(void)
487 {
488 	int err = init_inodecache();
489 	if (err)
490 		goto out1;
491 	err = register_filesystem(&adfs_fs_type);
492 	if (err)
493 		goto out;
494 	return 0;
495 out:
496 	destroy_inodecache();
497 out1:
498 	return err;
499 }
500 
501 static void __exit exit_adfs_fs(void)
502 {
503 	unregister_filesystem(&adfs_fs_type);
504 	destroy_inodecache();
505 }
506 
507 module_init(init_adfs_fs)
508 module_exit(exit_adfs_fs)
509