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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/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/slab.h>
 17 #include <linux/statfs.h>
 18 #include <linux/user_namespace.h>
 19 #include "adfs.h"
 20 #include "dir_f.h"
 21 #include "dir_fplus.h"
 22 
 23 #define ADFS_DEFAULT_OWNER_MASK S_IRWXU
 24 #define ADFS_DEFAULT_OTHER_MASK (S_IRWXG | S_IRWXO)
 25 
 26 void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
 27 {
 28         char error_buf[128];
 29         va_list args;
 30 
 31         va_start(args, fmt);
 32         vsnprintf(error_buf, sizeof(error_buf), fmt, args);
 33         va_end(args);
 34 
 35         printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %s\n",
 36                 sb->s_id, function ? ": " : "",
 37                 function ? function : "", error_buf);
 38 }
 39 
 40 static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
 41 {
 42         int i;
 43 
 44         /* sector size must be 256, 512 or 1024 bytes */
 45         if (dr->log2secsize != 8 &&
 46             dr->log2secsize != 9 &&
 47             dr->log2secsize != 10)
 48                 return 1;
 49 
 50         /* idlen must be at least log2secsize + 3 */
 51         if (dr->idlen < dr->log2secsize + 3)
 52                 return 1;
 53 
 54         /* we cannot have such a large disc that we
 55          * are unable to represent sector offsets in
 56          * 32 bits.  This works out at 2.0 TB.
 57          */
 58         if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
 59                 return 1;
 60 
 61         /* idlen must be no greater than 19 v2 [1.0] */
 62         if (dr->idlen > 19)
 63                 return 1;
 64 
 65         /* reserved bytes should be zero */
 66         for (i = 0; i < sizeof(dr->unused52); i++)
 67                 if (dr->unused52[i] != 0)
 68                         return 1;
 69 
 70         return 0;
 71 }
 72 
 73 static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
 74 {
 75         unsigned int v0, v1, v2, v3;
 76         int i;
 77 
 78         v0 = v1 = v2 = v3 = 0;
 79         for (i = sb->s_blocksize - 4; i; i -= 4) {
 80                 v0 += map[i]     + (v3 >> 8);
 81                 v3 &= 0xff;
 82                 v1 += map[i + 1] + (v0 >> 8);
 83                 v0 &= 0xff;
 84                 v2 += map[i + 2] + (v1 >> 8);
 85                 v1 &= 0xff;
 86                 v3 += map[i + 3] + (v2 >> 8);
 87                 v2 &= 0xff;
 88         }
 89         v0 +=           v3 >> 8;
 90         v1 += map[1] + (v0 >> 8);
 91         v2 += map[2] + (v1 >> 8);
 92         v3 += map[3] + (v2 >> 8);
 93 
 94         return v0 ^ v1 ^ v2 ^ v3;
 95 }
 96 
 97 static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
 98 {
 99         unsigned char crosscheck = 0, zonecheck = 1;
100         int i;
101 
102         for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
103                 unsigned char *map;
104 
105                 map = dm[i].dm_bh->b_data;
106 
107                 if (adfs_calczonecheck(sb, map) != map[0]) {
108                         adfs_error(sb, "zone %d fails zonecheck", i);
109                         zonecheck = 0;
110                 }
111                 crosscheck ^= map[3];
112         }
113         if (crosscheck != 0xff)
114                 adfs_error(sb, "crosscheck != 0xff");
115         return crosscheck == 0xff && zonecheck;
116 }
117 
118 static void adfs_put_super(struct super_block *sb)
119 {
120         int i;
121         struct adfs_sb_info *asb = ADFS_SB(sb);
122 
123         for (i = 0; i < asb->s_map_size; i++)
124                 brelse(asb->s_map[i].dm_bh);
125         kfree(asb->s_map);
126         kfree_rcu(asb, rcu);
127 }
128 
129 static int adfs_show_options(struct seq_file *seq, struct dentry *root)
130 {
131         struct adfs_sb_info *asb = ADFS_SB(root->d_sb);
132 
133         if (!uid_eq(asb->s_uid, GLOBAL_ROOT_UID))
134                 seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, asb->s_uid));
135         if (!gid_eq(asb->s_gid, GLOBAL_ROOT_GID))
136                 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, asb->s_gid));
137         if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
138                 seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
139         if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
140                 seq_printf(seq, ",othmask=%o", asb->s_other_mask);
141         if (asb->s_ftsuffix != 0)
142                 seq_printf(seq, ",ftsuffix=%u", asb->s_ftsuffix);
143 
144         return 0;
145 }
146 
147 enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix, Opt_err};
148 
149 static const match_table_t tokens = {
150         {Opt_uid, "uid=%u"},
151         {Opt_gid, "gid=%u"},
152         {Opt_ownmask, "ownmask=%o"},
153         {Opt_othmask, "othmask=%o"},
154         {Opt_ftsuffix, "ftsuffix=%u"},
155         {Opt_err, NULL}
156 };
157 
158 static int parse_options(struct super_block *sb, char *options)
159 {
160         char *p;
161         struct adfs_sb_info *asb = ADFS_SB(sb);
162         int option;
163 
164         if (!options)
165                 return 0;
166 
167         while ((p = strsep(&options, ",")) != NULL) {
168                 substring_t args[MAX_OPT_ARGS];
169                 int token;
170                 if (!*p)
171                         continue;
172 
173                 token = match_token(p, tokens, args);
174                 switch (token) {
175                 case Opt_uid:
176                         if (match_int(args, &option))
177                                 return -EINVAL;
178                         asb->s_uid = make_kuid(current_user_ns(), option);
179                         if (!uid_valid(asb->s_uid))
180                                 return -EINVAL;
181                         break;
182                 case Opt_gid:
183                         if (match_int(args, &option))
184                                 return -EINVAL;
185                         asb->s_gid = make_kgid(current_user_ns(), option);
186                         if (!gid_valid(asb->s_gid))
187                                 return -EINVAL;
188                         break;
189                 case Opt_ownmask:
190                         if (match_octal(args, &option))
191                                 return -EINVAL;
192                         asb->s_owner_mask = option;
193                         break;
194                 case Opt_othmask:
195                         if (match_octal(args, &option))
196                                 return -EINVAL;
197                         asb->s_other_mask = option;
198                         break;
199                 case Opt_ftsuffix:
200                         if (match_int(args, &option))
201                                 return -EINVAL;
202                         asb->s_ftsuffix = option;
203                         break;
204                 default:
205                         printk("ADFS-fs: unrecognised mount option \"%s\" "
206                                         "or missing value\n", p);
207                         return -EINVAL;
208                 }
209         }
210         return 0;
211 }
212 
213 static int adfs_remount(struct super_block *sb, int *flags, char *data)
214 {
215         sync_filesystem(sb);
216         *flags |= MS_NODIRATIME;
217         return parse_options(sb, data);
218 }
219 
220 static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
221 {
222         struct super_block *sb = dentry->d_sb;
223         struct adfs_sb_info *sbi = ADFS_SB(sb);
224         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
225 
226         buf->f_type    = ADFS_SUPER_MAGIC;
227         buf->f_namelen = sbi->s_namelen;
228         buf->f_bsize   = sb->s_blocksize;
229         buf->f_blocks  = sbi->s_size;
230         buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;
231         buf->f_bavail  =
232         buf->f_bfree   = adfs_map_free(sb);
233         buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
234         buf->f_fsid.val[0] = (u32)id;
235         buf->f_fsid.val[1] = (u32)(id >> 32);
236 
237         return 0;
238 }
239 
240 static struct kmem_cache *adfs_inode_cachep;
241 
242 static struct inode *adfs_alloc_inode(struct super_block *sb)
243 {
244         struct adfs_inode_info *ei;
245         ei = (struct adfs_inode_info *)kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
246         if (!ei)
247                 return NULL;
248         return &ei->vfs_inode;
249 }
250 
251 static void adfs_i_callback(struct rcu_head *head)
252 {
253         struct inode *inode = container_of(head, struct inode, i_rcu);
254         kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
255 }
256 
257 static void adfs_destroy_inode(struct inode *inode)
258 {
259         call_rcu(&inode->i_rcu, adfs_i_callback);
260 }
261 
262 static void init_once(void *foo)
263 {
264         struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
265 
266         inode_init_once(&ei->vfs_inode);
267 }
268 
269 static int __init init_inodecache(void)
270 {
271         adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
272                                              sizeof(struct adfs_inode_info),
273                                              0, (SLAB_RECLAIM_ACCOUNT|
274                                                 SLAB_MEM_SPREAD),
275                                              init_once);
276         if (adfs_inode_cachep == NULL)
277                 return -ENOMEM;
278         return 0;
279 }
280 
281 static void destroy_inodecache(void)
282 {
283         /*
284          * Make sure all delayed rcu free inodes are flushed before we
285          * destroy cache.
286          */
287         rcu_barrier();
288         kmem_cache_destroy(adfs_inode_cachep);
289 }
290 
291 static const struct super_operations adfs_sops = {
292         .alloc_inode    = adfs_alloc_inode,
293         .destroy_inode  = adfs_destroy_inode,
294         .write_inode    = adfs_write_inode,
295         .put_super      = adfs_put_super,
296         .statfs         = adfs_statfs,
297         .remount_fs     = adfs_remount,
298         .show_options   = adfs_show_options,
299 };
300 
301 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
302 {
303         struct adfs_discmap *dm;
304         unsigned int map_addr, zone_size, nzones;
305         int i, zone;
306         struct adfs_sb_info *asb = ADFS_SB(sb);
307 
308         nzones    = asb->s_map_size;
309         zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
310         map_addr  = (nzones >> 1) * zone_size -
311                      ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
312         map_addr  = signed_asl(map_addr, asb->s_map2blk);
313 
314         asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
315 
316         dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
317         if (dm == NULL) {
318                 adfs_error(sb, "not enough memory");
319                 return NULL;
320         }
321 
322         for (zone = 0; zone < nzones; zone++, map_addr++) {
323                 dm[zone].dm_startbit = 0;
324                 dm[zone].dm_endbit   = zone_size;
325                 dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
326                 dm[zone].dm_bh       = sb_bread(sb, map_addr);
327 
328                 if (!dm[zone].dm_bh) {
329                         adfs_error(sb, "unable to read map");
330                         goto error_free;
331                 }
332         }
333 
334         /* adjust the limits for the first and last map zones */
335         i = zone - 1;
336         dm[0].dm_startblk = 0;
337         dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
338         dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
339                             (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
340                             (ADFS_DR_SIZE_BITS - i * zone_size);
341 
342         if (adfs_checkmap(sb, dm))
343                 return dm;
344 
345         adfs_error(sb, "map corrupted");
346 
347 error_free:
348         while (--zone >= 0)
349                 brelse(dm[zone].dm_bh);
350 
351         kfree(dm);
352         return NULL;
353 }
354 
355 static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
356 {
357         unsigned long discsize;
358 
359         discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
360         discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
361 
362         return discsize;
363 }
364 
365 static int adfs_fill_super(struct super_block *sb, void *data, int silent)
366 {
367         struct adfs_discrecord *dr;
368         struct buffer_head *bh;
369         struct object_info root_obj;
370         unsigned char *b_data;
371         struct adfs_sb_info *asb;
372         struct inode *root;
373 
374         sb->s_flags |= MS_NODIRATIME;
375 
376         asb = kzalloc(sizeof(*asb), GFP_KERNEL);
377         if (!asb)
378                 return -ENOMEM;
379         sb->s_fs_info = asb;
380 
381         /* set default options */
382         asb->s_uid = GLOBAL_ROOT_UID;
383         asb->s_gid = GLOBAL_ROOT_GID;
384         asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
385         asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
386         asb->s_ftsuffix = 0;
387 
388         if (parse_options(sb, data))
389                 goto error;
390 
391         sb_set_blocksize(sb, BLOCK_SIZE);
392         if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
393                 adfs_error(sb, "unable to read superblock");
394                 goto error;
395         }
396 
397         b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
398 
399         if (adfs_checkbblk(b_data)) {
400                 if (!silent)
401                         printk("VFS: Can't find an adfs filesystem on dev "
402                                 "%s.\n", sb->s_id);
403                 goto error_free_bh;
404         }
405 
406         dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
407 
408         /*
409          * Do some sanity checks on the ADFS disc record
410          */
411         if (adfs_checkdiscrecord(dr)) {
412                 if (!silent)
413                         printk("VPS: Can't find an adfs filesystem on dev "
414                                 "%s.\n", sb->s_id);
415                 goto error_free_bh;
416         }
417 
418         brelse(bh);
419         if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
420                 bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
421                 if (!bh) {
422                         adfs_error(sb, "couldn't read superblock on "
423                                 "2nd try.");
424                         goto error;
425                 }
426                 b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
427                 if (adfs_checkbblk(b_data)) {
428                         adfs_error(sb, "disc record mismatch, very weird!");
429                         goto error_free_bh;
430                 }
431                 dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
432         } else {
433                 if (!silent)
434                         printk(KERN_ERR "VFS: Unsupported blocksize on dev "
435                                 "%s.\n", sb->s_id);
436                 goto error;
437         }
438 
439         /*
440          * blocksize on this device should now be set to the ADFS log2secsize
441          */
442 
443         sb->s_magic             = ADFS_SUPER_MAGIC;
444         asb->s_idlen            = dr->idlen;
445         asb->s_map_size         = dr->nzones | (dr->nzones_high << 8);
446         asb->s_map2blk          = dr->log2bpmb - dr->log2secsize;
447         asb->s_size             = adfs_discsize(dr, sb->s_blocksize_bits);
448         asb->s_version          = dr->format_version;
449         asb->s_log2sharesize    = dr->log2sharesize;
450         
451         asb->s_map = adfs_read_map(sb, dr);
452         if (!asb->s_map)
453                 goto error_free_bh;
454 
455         brelse(bh);
456 
457         /*
458          * set up enough so that we can read an inode
459          */
460         sb->s_op = &adfs_sops;
461 
462         dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
463 
464         root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
465         root_obj.name_len  = 0;
466         /* Set root object date as 01 Jan 1987 00:00:00 */
467         root_obj.loadaddr  = 0xfff0003f;
468         root_obj.execaddr  = 0xec22c000;
469         root_obj.size      = ADFS_NEWDIR_SIZE;
470         root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
471                              ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
472         root_obj.filetype  = -1;
473 
474         /*
475          * If this is a F+ disk with variable length directories,
476          * get the root_size from the disc record.
477          */
478         if (asb->s_version) {
479                 root_obj.size = le32_to_cpu(dr->root_size);
480                 asb->s_dir     = &adfs_fplus_dir_ops;
481                 asb->s_namelen = ADFS_FPLUS_NAME_LEN;
482         } else {
483                 asb->s_dir     = &adfs_f_dir_ops;
484                 asb->s_namelen = ADFS_F_NAME_LEN;
485         }
486         /*
487          * ,xyz hex filetype suffix may be added by driver
488          * to files that have valid RISC OS filetype
489          */
490         if (asb->s_ftsuffix)
491                 asb->s_namelen += 4;
492 
493         sb->s_d_op = &adfs_dentry_operations;
494         root = adfs_iget(sb, &root_obj);
495         sb->s_root = d_make_root(root);
496         if (!sb->s_root) {
497                 int i;
498                 for (i = 0; i < asb->s_map_size; i++)
499                         brelse(asb->s_map[i].dm_bh);
500                 kfree(asb->s_map);
501                 adfs_error(sb, "get root inode failed\n");
502                 goto error;
503         }
504         return 0;
505 
506 error_free_bh:
507         brelse(bh);
508 error:
509         sb->s_fs_info = NULL;
510         kfree(asb);
511         return -EINVAL;
512 }
513 
514 static struct dentry *adfs_mount(struct file_system_type *fs_type,
515         int flags, const char *dev_name, void *data)
516 {
517         return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
518 }
519 
520 static struct file_system_type adfs_fs_type = {
521         .owner          = THIS_MODULE,
522         .name           = "adfs",
523         .mount          = adfs_mount,
524         .kill_sb        = kill_block_super,
525         .fs_flags       = FS_REQUIRES_DEV,
526 };
527 MODULE_ALIAS_FS("adfs");
528 
529 static int __init init_adfs_fs(void)
530 {
531         int err = init_inodecache();
532         if (err)
533                 goto out1;
534         err = register_filesystem(&adfs_fs_type);
535         if (err)
536                 goto out;
537         return 0;
538 out:
539         destroy_inodecache();
540 out1:
541         return err;
542 }
543 
544 static void __exit exit_adfs_fs(void)
545 {
546         unregister_filesystem(&adfs_fs_type);
547         destroy_inodecache();
548 }
549 
550 module_init(init_adfs_fs)
551 module_exit(exit_adfs_fs)
552 MODULE_LICENSE("GPL");
553 

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