File: /usr/src/linux/fs/adfs/super.c
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/version.h>
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/adfs_fs.h>
15 #include <linux/slab.h>
16 #include <linux/sched.h>
17 #include <linux/stat.h>
18 #include <linux/string.h>
19 #include <linux/locks.h>
20 #include <linux/init.h>
21
22 #include <asm/bitops.h>
23 #include <asm/uaccess.h>
24 #include <asm/system.h>
25
26 #include <stdarg.h>
27
28 #include "adfs.h"
29 #include "dir_f.h"
30 #include "dir_fplus.h"
31
32 void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
33 {
34 char error_buf[128];
35 va_list args;
36
37 va_start(args, fmt);
38 vsprintf(error_buf, fmt, args);
39 va_end(args);
40
41 printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %s\n",
42 kdevname(sb->s_dev), function ? ": " : "",
43 function ? function : "", error_buf);
44 }
45
46 static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
47 {
48 int i;
49
50 /* sector size must be 256, 512 or 1024 bytes */
51 if (dr->log2secsize != 8 &&
52 dr->log2secsize != 9 &&
53 dr->log2secsize != 10)
54 return 1;
55
56 /* idlen must be at least log2secsize + 3 */
57 if (dr->idlen < dr->log2secsize + 3)
58 return 1;
59
60 /* we cannot have such a large disc that we
61 * are unable to represent sector offsets in
62 * 32 bits. This works out at 2.0 TB.
63 */
64 if (dr->disc_size_high >> dr->log2secsize)
65 return 1;
66
67 /*
68 * The following checks are not required for F+
69 * stage 1.
70 */
71 #if 0
72 /* idlen must be smaller be no greater than 15 */
73 if (dr->idlen > 15)
74 return 1;
75
76 /* nzones must be less than 128 for the root
77 * directory to be addressable
78 */
79 if (dr->nzones >= 128 && dr->nzones_high == 0)
80 return 1;
81
82 /* root must be of the form 0x2.. */
83 if ((le32_to_cpu(dr->root) & 0xffffff00) != 0x00000200)
84 return 1;
85 #else
86 /*
87 * Stage 2 F+ does not require the following check
88 */
89 #if 0
90 /* idlen must be no greater than 16 v2 [1.0] */
91 if (dr->idlen > 16)
92 return 1;
93
94 /* we can't handle F+ discs yet */
95 if (dr->format_version || dr->root_size)
96 return 1;
97
98 #else
99 /* idlen must be no greater than 19 v2 [1.0] */
100 if (dr->idlen > 19)
101 return 1;
102 #endif
103 #endif
104
105 /* reserved bytes should be zero */
106 for (i = 0; i < sizeof(dr->unused52); i++)
107 if (dr->unused52[i] != 0)
108 return 1;
109
110 return 0;
111 }
112
113 static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
114 {
115 unsigned int v0, v1, v2, v3;
116 int i;
117
118 v0 = v1 = v2 = v3 = 0;
119 for (i = sb->s_blocksize - 4; i; i -= 4) {
120 v0 += map[i] + (v3 >> 8);
121 v3 &= 0xff;
122 v1 += map[i + 1] + (v0 >> 8);
123 v0 &= 0xff;
124 v2 += map[i + 2] + (v1 >> 8);
125 v1 &= 0xff;
126 v3 += map[i + 3] + (v2 >> 8);
127 v2 &= 0xff;
128 }
129 v0 += v3 >> 8;
130 v1 += map[1] + (v0 >> 8);
131 v2 += map[2] + (v1 >> 8);
132 v3 += map[3] + (v2 >> 8);
133
134 return v0 ^ v1 ^ v2 ^ v3;
135 }
136
137 static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
138 {
139 unsigned char crosscheck = 0, zonecheck = 1;
140 int i;
141
142 for (i = 0; i < sb->u.adfs_sb.s_map_size; i++) {
143 unsigned char *map;
144
145 map = dm[i].dm_bh->b_data;
146
147 if (adfs_calczonecheck(sb, map) != map[0]) {
148 adfs_error(sb, "zone %d fails zonecheck", i);
149 zonecheck = 0;
150 }
151 crosscheck ^= map[3];
152 }
153 if (crosscheck != 0xff)
154 adfs_error(sb, "crosscheck != 0xff");
155 return crosscheck == 0xff && zonecheck;
156 }
157
158 static void adfs_put_super(struct super_block *sb)
159 {
160 int i;
161
162 for (i = 0; i < sb->u.adfs_sb.s_map_size; i++)
163 brelse(sb->u.adfs_sb.s_map[i].dm_bh);
164 kfree(sb->u.adfs_sb.s_map);
165 }
166
167 static int parse_options(struct super_block *sb, char *options)
168 {
169 char *value, *opt;
170
171 if (!options)
172 return 0;
173
174 for (opt = strtok(options, ","); opt != NULL; opt = strtok(NULL, ",")) {
175 value = strchr(opt, '=');
176 if (value)
177 *value++ = '\0';
178
179 if (!strcmp(opt, "uid")) { /* owner of all files */
180 if (!value || !*value)
181 return -EINVAL;
182 sb->u.adfs_sb.s_uid = simple_strtoul(value, &value, 0);
183 if (*value)
184 return -EINVAL;
185 } else
186 if (!strcmp(opt, "gid")) { /* group owner of all files */
187 if (!value || !*value)
188 return -EINVAL;
189 sb->u.adfs_sb.s_gid = simple_strtoul(value, &value, 0);
190 if (*value)
191 return -EINVAL;
192 } else
193 if (!strcmp(opt, "ownmask")) { /* owner permission mask */
194 if (!value || !*value)
195 return -EINVAL;
196 sb->u.adfs_sb.s_owner_mask = simple_strtoul(value, &value, 8);
197 if (*value)
198 return -EINVAL;
199 } else
200 if (!strcmp(opt, "othmask")) { /* others permission mask */
201 if (!value || !*value)
202 return -EINVAL;
203 sb->u.adfs_sb.s_other_mask = simple_strtoul(value, &value, 8);
204 if (*value)
205 return -EINVAL;
206 } else { /* eh? say again. */
207 printk("ADFS-fs: unrecognised mount option %s\n", opt);
208 return -EINVAL;
209 }
210 }
211 return 0;
212 }
213
214 static int adfs_remount(struct super_block *sb, int *flags, char *data)
215 {
216 return parse_options(sb, data);
217 }
218
219 static int adfs_statfs(struct super_block *sb, struct statfs *buf)
220 {
221 struct adfs_sb_info *asb = &sb->u.adfs_sb;
222
223 buf->f_type = ADFS_SUPER_MAGIC;
224 buf->f_namelen = asb->s_namelen;
225 buf->f_bsize = sb->s_blocksize;
226 buf->f_blocks = asb->s_size;
227 buf->f_files = asb->s_ids_per_zone * asb->s_map_size;
228 buf->f_bavail =
229 buf->f_bfree = adfs_map_free(sb);
230 buf->f_ffree = buf->f_bfree * buf->f_files / buf->f_blocks;
231
232 return 0;
233 }
234
235 static struct super_operations adfs_sops = {
236 write_inode: adfs_write_inode,
237 put_super: adfs_put_super,
238 statfs: adfs_statfs,
239 remount_fs: adfs_remount,
240 };
241
242 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
243 {
244 struct adfs_discmap *dm;
245 unsigned int map_addr, zone_size, nzones;
246 int i, zone;
247
248 nzones = sb->u.adfs_sb.s_map_size;
249 zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
250 map_addr = (nzones >> 1) * zone_size -
251 ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
252 map_addr = signed_asl(map_addr, sb->u.adfs_sb.s_map2blk);
253
254 sb->u.adfs_sb.s_ids_per_zone = zone_size / (sb->u.adfs_sb.s_idlen + 1);
255
256 dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
257 if (dm == NULL) {
258 adfs_error(sb, "not enough memory");
259 return NULL;
260 }
261
262 for (zone = 0; zone < nzones; zone++, map_addr++) {
263 dm[zone].dm_startbit = 0;
264 dm[zone].dm_endbit = zone_size;
265 dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
266 dm[zone].dm_bh = bread(sb->s_dev, map_addr, sb->s_blocksize);
267
268 if (!dm[zone].dm_bh) {
269 adfs_error(sb, "unable to read map");
270 goto error_free;
271 }
272 }
273
274 /* adjust the limits for the first and last map zones */
275 i = zone - 1;
276 dm[0].dm_startblk = 0;
277 dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
278 dm[i].dm_endbit = (dr->disc_size_high << (32 - dr->log2bpmb)) +
279 (dr->disc_size >> dr->log2bpmb) +
280 (ADFS_DR_SIZE_BITS - i * zone_size);
281
282 if (adfs_checkmap(sb, dm))
283 return dm;
284
285 adfs_error(sb, NULL, "map corrupted");
286
287 error_free:
288 while (--zone >= 0)
289 brelse(dm[zone].dm_bh);
290
291 kfree(dm);
292 return NULL;
293 }
294
295 static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
296 {
297 unsigned long discsize;
298
299 discsize = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
300 discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
301
302 return discsize;
303 }
304
305 struct super_block *adfs_read_super(struct super_block *sb, void *data, int silent)
306 {
307 struct adfs_discrecord *dr;
308 struct buffer_head *bh;
309 struct object_info root_obj;
310 unsigned char *b_data;
311 kdev_t dev = sb->s_dev;
312
313 /* set default options */
314 sb->u.adfs_sb.s_uid = 0;
315 sb->u.adfs_sb.s_gid = 0;
316 sb->u.adfs_sb.s_owner_mask = S_IRWXU;
317 sb->u.adfs_sb.s_other_mask = S_IRWXG | S_IRWXO;
318
319 if (parse_options(sb, data))
320 goto error;
321
322 set_blocksize(dev, BLOCK_SIZE);
323 if (!(bh = bread(dev, ADFS_DISCRECORD / BLOCK_SIZE, BLOCK_SIZE))) {
324 adfs_error(sb, "unable to read superblock");
325 goto error;
326 }
327
328 b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
329
330 if (adfs_checkbblk(b_data)) {
331 if (!silent)
332 printk("VFS: Can't find an adfs filesystem on dev "
333 "%s.\n", kdevname(dev));
334 goto error_free_bh;
335 }
336
337 dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
338
339 /*
340 * Do some sanity checks on the ADFS disc record
341 */
342 if (adfs_checkdiscrecord(dr)) {
343 if (!silent)
344 printk("VPS: Can't find an adfs filesystem on dev "
345 "%s.\n", kdevname(dev));
346 goto error_free_bh;
347 }
348
349 sb->s_blocksize_bits = dr->log2secsize;
350 sb->s_blocksize = 1 << sb->s_blocksize_bits;
351 if (sb->s_blocksize != BLOCK_SIZE &&
352 (sb->s_blocksize == 512 || sb->s_blocksize == 1024 ||
353 sb->s_blocksize == 2048 || sb->s_blocksize == 4096)) {
354
355 brelse(bh);
356 set_blocksize(dev, sb->s_blocksize);
357 bh = bread(dev, ADFS_DISCRECORD / sb->s_blocksize, sb->s_blocksize);
358 if (!bh) {
359 adfs_error(sb, "couldn't read superblock on "
360 "2nd try.");
361 goto error;
362 }
363 b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
364 if (adfs_checkbblk(b_data)) {
365 adfs_error(sb, "disc record mismatch, very weird!");
366 goto error_free_bh;
367 }
368 dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
369 }
370 if (sb->s_blocksize != bh->b_size) {
371 if (!silent)
372 printk(KERN_ERR "VFS: Unsupported blocksize on dev "
373 "%s.\n", kdevname(dev));
374 goto error_free_bh;
375 }
376
377 /*
378 * blocksize on this device should now be set to the ADFS log2secsize
379 */
380
381 sb->s_magic = ADFS_SUPER_MAGIC;
382 sb->u.adfs_sb.s_idlen = dr->idlen;
383 sb->u.adfs_sb.s_map_size = dr->nzones | (dr->nzones_high << 8);
384 sb->u.adfs_sb.s_map2blk = dr->log2bpmb - dr->log2secsize;
385 sb->u.adfs_sb.s_size = adfs_discsize(dr, sb->s_blocksize_bits);
386 sb->u.adfs_sb.s_version = dr->format_version;
387 sb->u.adfs_sb.s_log2sharesize = dr->log2sharesize;
388
389 sb->u.adfs_sb.s_map = adfs_read_map(sb, dr);
390 if (!sb->u.adfs_sb.s_map)
391 goto error_free_bh;
392
393 brelse(bh);
394
395 /*
396 * set up enough so that we can read an inode
397 */
398 sb->s_op = &adfs_sops;
399
400 dr = (struct adfs_discrecord *)(sb->u.adfs_sb.s_map[0].dm_bh->b_data + 4);
401
402 root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
403 root_obj.name_len = 0;
404 root_obj.loadaddr = 0;
405 root_obj.execaddr = 0;
406 root_obj.size = ADFS_NEWDIR_SIZE;
407 root_obj.attr = ADFS_NDA_DIRECTORY | ADFS_NDA_OWNER_READ |
408 ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
409
410 /*
411 * If this is a F+ disk with variable length directories,
412 * get the root_size from the disc record.
413 */
414 if (sb->u.adfs_sb.s_version) {
415 root_obj.size = dr->root_size;
416 sb->u.adfs_sb.s_dir = &adfs_fplus_dir_ops;
417 sb->u.adfs_sb.s_namelen = ADFS_FPLUS_NAME_LEN;
418 } else {
419 sb->u.adfs_sb.s_dir = &adfs_f_dir_ops;
420 sb->u.adfs_sb.s_namelen = ADFS_F_NAME_LEN;
421 }
422
423 sb->s_root = d_alloc_root(adfs_iget(sb, &root_obj));
424 if (!sb->s_root) {
425 int i;
426
427 for (i = 0; i < sb->u.adfs_sb.s_map_size; i++)
428 brelse(sb->u.adfs_sb.s_map[i].dm_bh);
429 kfree(sb->u.adfs_sb.s_map);
430 adfs_error(sb, "get root inode failed\n");
431 goto error;
432 } else
433 sb->s_root->d_op = &adfs_dentry_operations;
434 return sb;
435
436 error_free_bh:
437 brelse(bh);
438 error:
439 return NULL;
440 }
441
442 static DECLARE_FSTYPE_DEV(adfs_fs_type, "adfs", adfs_read_super);
443
444 static int __init init_adfs_fs(void)
445 {
446 return register_filesystem(&adfs_fs_type);
447 }
448
449 static void __exit exit_adfs_fs(void)
450 {
451 unregister_filesystem(&adfs_fs_type);
452 }
453
454 EXPORT_NO_SYMBOLS;
455
456 module_init(init_adfs_fs)
457 module_exit(exit_adfs_fs)
458