xref: /openbmc/linux/fs/adfs/super.c (revision 96de0e252cedffad61b3cb5e05662c591898e69a) 
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 	vsnprintf(error_buf, sizeof(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 dentry *dentry, struct kstatfs *buf)
200 {
201 	struct adfs_sb_info *asb = ADFS_SB(dentry->d_sb);
202 
203 	buf->f_type    = ADFS_SUPER_MAGIC;
204 	buf->f_namelen = asb->s_namelen;
205 	buf->f_bsize   = dentry->d_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(dentry->d_sb);
210 	buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
211 
212 	return 0;
213 }
214 
215 static struct kmem_cache *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, GFP_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(struct kmem_cache *cachep, void *foo)
232 {
233 	struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
234 
235 	inode_init_once(&ei->vfs_inode);
236 }
237 
238 static int init_inodecache(void)
239 {
240 	adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
241 					     sizeof(struct adfs_inode_info),
242 					     0, (SLAB_RECLAIM_ACCOUNT|
243 						SLAB_MEM_SPREAD),
244 					     init_once);
245 	if (adfs_inode_cachep == NULL)
246 		return -ENOMEM;
247 	return 0;
248 }
249 
250 static void destroy_inodecache(void)
251 {
252 	kmem_cache_destroy(adfs_inode_cachep);
253 }
254 
255 static const struct super_operations adfs_sops = {
256 	.alloc_inode	= adfs_alloc_inode,
257 	.destroy_inode	= adfs_destroy_inode,
258 	.write_inode	= adfs_write_inode,
259 	.put_super	= adfs_put_super,
260 	.statfs		= adfs_statfs,
261 	.remount_fs	= adfs_remount,
262 };
263 
264 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
265 {
266 	struct adfs_discmap *dm;
267 	unsigned int map_addr, zone_size, nzones;
268 	int i, zone;
269 	struct adfs_sb_info *asb = ADFS_SB(sb);
270 
271 	nzones    = asb->s_map_size;
272 	zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
273 	map_addr  = (nzones >> 1) * zone_size -
274 		     ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
275 	map_addr  = signed_asl(map_addr, asb->s_map2blk);
276 
277 	asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
278 
279 	dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
280 	if (dm == NULL) {
281 		adfs_error(sb, "not enough memory");
282 		return NULL;
283 	}
284 
285 	for (zone = 0; zone < nzones; zone++, map_addr++) {
286 		dm[zone].dm_startbit = 0;
287 		dm[zone].dm_endbit   = zone_size;
288 		dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
289 		dm[zone].dm_bh       = sb_bread(sb, map_addr);
290 
291 		if (!dm[zone].dm_bh) {
292 			adfs_error(sb, "unable to read map");
293 			goto error_free;
294 		}
295 	}
296 
297 	/* adjust the limits for the first and last map zones */
298 	i = zone - 1;
299 	dm[0].dm_startblk = 0;
300 	dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
301 	dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
302 			    (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
303 			    (ADFS_DR_SIZE_BITS - i * zone_size);
304 
305 	if (adfs_checkmap(sb, dm))
306 		return dm;
307 
308 	adfs_error(sb, "map corrupted");
309 
310 error_free:
311 	while (--zone >= 0)
312 		brelse(dm[zone].dm_bh);
313 
314 	kfree(dm);
315 	return NULL;
316 }
317 
318 static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
319 {
320 	unsigned long discsize;
321 
322 	discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
323 	discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
324 
325 	return discsize;
326 }
327 
328 static int adfs_fill_super(struct super_block *sb, void *data, int silent)
329 {
330 	struct adfs_discrecord *dr;
331 	struct buffer_head *bh;
332 	struct object_info root_obj;
333 	unsigned char *b_data;
334 	struct adfs_sb_info *asb;
335 	struct inode *root;
336 
337 	sb->s_flags |= MS_NODIRATIME;
338 
339 	asb = kzalloc(sizeof(*asb), GFP_KERNEL);
340 	if (!asb)
341 		return -ENOMEM;
342 	sb->s_fs_info = asb;
343 
344 	/* set default options */
345 	asb->s_uid = 0;
346 	asb->s_gid = 0;
347 	asb->s_owner_mask = S_IRWXU;
348 	asb->s_other_mask = S_IRWXG | S_IRWXO;
349 
350 	if (parse_options(sb, data))
351 		goto error;
352 
353 	sb_set_blocksize(sb, BLOCK_SIZE);
354 	if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
355 		adfs_error(sb, "unable to read superblock");
356 		goto error;
357 	}
358 
359 	b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
360 
361 	if (adfs_checkbblk(b_data)) {
362 		if (!silent)
363 			printk("VFS: Can't find an adfs filesystem on dev "
364 				"%s.\n", sb->s_id);
365 		goto error_free_bh;
366 	}
367 
368 	dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
369 
370 	/*
371 	 * Do some sanity checks on the ADFS disc record
372 	 */
373 	if (adfs_checkdiscrecord(dr)) {
374 		if (!silent)
375 			printk("VPS: Can't find an adfs filesystem on dev "
376 				"%s.\n", sb->s_id);
377 		goto error_free_bh;
378 	}
379 
380 	brelse(bh);
381 	if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
382 		bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
383 		if (!bh) {
384 			adfs_error(sb, "couldn't read superblock on "
385 				"2nd try.");
386 			goto error;
387 		}
388 		b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
389 		if (adfs_checkbblk(b_data)) {
390 			adfs_error(sb, "disc record mismatch, very weird!");
391 			goto error_free_bh;
392 		}
393 		dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
394 	} else {
395 		if (!silent)
396 			printk(KERN_ERR "VFS: Unsupported blocksize on dev "
397 				"%s.\n", sb->s_id);
398 		goto error;
399 	}
400 
401 	/*
402 	 * blocksize on this device should now be set to the ADFS log2secsize
403 	 */
404 
405 	sb->s_magic		= ADFS_SUPER_MAGIC;
406 	asb->s_idlen		= dr->idlen;
407 	asb->s_map_size		= dr->nzones | (dr->nzones_high << 8);
408 	asb->s_map2blk		= dr->log2bpmb - dr->log2secsize;
409 	asb->s_size    		= adfs_discsize(dr, sb->s_blocksize_bits);
410 	asb->s_version 		= dr->format_version;
411 	asb->s_log2sharesize	= dr->log2sharesize;
412 
413 	asb->s_map = adfs_read_map(sb, dr);
414 	if (!asb->s_map)
415 		goto error_free_bh;
416 
417 	brelse(bh);
418 
419 	/*
420 	 * set up enough so that we can read an inode
421 	 */
422 	sb->s_op = &adfs_sops;
423 
424 	dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
425 
426 	root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
427 	root_obj.name_len  = 0;
428 	root_obj.loadaddr  = 0;
429 	root_obj.execaddr  = 0;
430 	root_obj.size	   = ADFS_NEWDIR_SIZE;
431 	root_obj.attr	   = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
432 			     ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
433 
434 	/*
435 	 * If this is a F+ disk with variable length directories,
436 	 * get the root_size from the disc record.
437 	 */
438 	if (asb->s_version) {
439 		root_obj.size = le32_to_cpu(dr->root_size);
440 		asb->s_dir     = &adfs_fplus_dir_ops;
441 		asb->s_namelen = ADFS_FPLUS_NAME_LEN;
442 	} else {
443 		asb->s_dir     = &adfs_f_dir_ops;
444 		asb->s_namelen = ADFS_F_NAME_LEN;
445 	}
446 
447 	root = adfs_iget(sb, &root_obj);
448 	sb->s_root = d_alloc_root(root);
449 	if (!sb->s_root) {
450 		int i;
451 		iput(root);
452 		for (i = 0; i < asb->s_map_size; i++)
453 			brelse(asb->s_map[i].dm_bh);
454 		kfree(asb->s_map);
455 		adfs_error(sb, "get root inode failed\n");
456 		goto error;
457 	} else
458 		sb->s_root->d_op = &adfs_dentry_operations;
459 	return 0;
460 
461 error_free_bh:
462 	brelse(bh);
463 error:
464 	sb->s_fs_info = NULL;
465 	kfree(asb);
466 	return -EINVAL;
467 }
468 
469 static int adfs_get_sb(struct file_system_type *fs_type,
470 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
471 {
472 	return get_sb_bdev(fs_type, flags, dev_name, data, adfs_fill_super,
473 			   mnt);
474 }
475 
476 static struct file_system_type adfs_fs_type = {
477 	.owner		= THIS_MODULE,
478 	.name		= "adfs",
479 	.get_sb		= adfs_get_sb,
480 	.kill_sb	= kill_block_super,
481 	.fs_flags	= FS_REQUIRES_DEV,
482 };
483 
484 static int __init init_adfs_fs(void)
485 {
486 	int err = init_inodecache();
487 	if (err)
488 		goto out1;
489 	err = register_filesystem(&adfs_fs_type);
490 	if (err)
491 		goto out;
492 	return 0;
493 out:
494 	destroy_inodecache();
495 out1:
496 	return err;
497 }
498 
499 static void __exit exit_adfs_fs(void)
500 {
501 	unregister_filesystem(&adfs_fs_type);
502 	destroy_inodecache();
503 }
504 
505 module_init(init_adfs_fs)
506 module_exit(exit_adfs_fs)
507