fs/adfs/super.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/fs/adfs/super.c
   4  *
   5  *  Copyright (C) 1997-1999 Russell King
   6  */
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/fs_parser.h>
  10 #include <linux/fs_context.h>
  11 #include <linux/mount.h>
  12 #include <linux/seq_file.h>
  13 #include <linux/slab.h>
  14 #include <linux/statfs.h>
  15 #include <linux/user_namespace.h>
  16 #include <linux/blkdev.h>
  17 #include "adfs.h"
  18 #include "dir_f.h"
  19 #include "dir_fplus.h"
  20
  21 #define ADFS_SB_FLAGS SB_NOATIME
  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         struct va_format vaf;
  29         va_list args;
  30
  31         va_start(args, fmt);
  32         vaf.fmt = fmt;
  33         vaf.va = &args;
  34
  35         printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %pV\n",
  36                 sb->s_id, function ? ": " : "",
  37                 function ? function : "", &vaf);
  38
  39         va_end(args);
  40 }
  41
  42 void adfs_msg(struct super_block *sb, const char *pfx, const char *fmt, ...)
  43 {
  44         struct va_format vaf;
  45         va_list args;
  46
  47         va_start(args, fmt);
  48         vaf.fmt = fmt;
  49         vaf.va = &args;
  50         printk("%sADFS-fs (%s): %pV\n", pfx, sb->s_id, &vaf);
  51         va_end(args);
  52 }
  53
  54 static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
  55 {
  56         unsigned int max_idlen;
  57         int i;
  58
  59         /* sector size must be 256, 512 or 1024 bytes */
  60         if (dr->log2secsize != 8 &&
  61             dr->log2secsize != 9 &&
  62             dr->log2secsize != 10)
  63                 return 1;
  64
  65         /* idlen must be at least log2secsize + 3 */
  66         if (dr->idlen < dr->log2secsize + 3)
  67                 return 1;
  68
  69         /* we cannot have such a large disc that we
  70          * are unable to represent sector offsets in
  71          * 32 bits.  This works out at 2.0 TB.
  72          */
  73         if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
  74                 return 1;
  75
  76         /*
  77          * Maximum idlen is limited to 16 bits for new directories by
  78          * the three-byte storage of an indirect disc address.  For
  79          * big directories, idlen must be no greater than 19 v2 [1.0]
  80          */
  81         max_idlen = dr->format_version ? 19 : 16;
  82         if (dr->idlen > max_idlen)
  83                 return 1;
  84
  85         /* reserved bytes should be zero */
  86         for (i = 0; i < sizeof(dr->unused52); i++)
  87                 if (dr->unused52[i] != 0)
  88                         return 1;
  89
  90         return 0;
  91 }
  92
  93 static void adfs_put_super(struct super_block *sb)
  94 {
  95         struct adfs_sb_info *asb = ADFS_SB(sb);
  96
  97         adfs_free_map(sb);
  98         kfree_rcu(asb, rcu);
  99 }
 100
 101 static int adfs_show_options(struct seq_file *seq, struct dentry *root)
 102 {
 103         struct adfs_sb_info *asb = ADFS_SB(root->d_sb);
 104
 105         if (!uid_eq(asb->s_uid, GLOBAL_ROOT_UID))
 106                 seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, asb->s_uid));
 107         if (!gid_eq(asb->s_gid, GLOBAL_ROOT_GID))
 108                 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, asb->s_gid));
 109         if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
 110                 seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
 111         if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
 112                 seq_printf(seq, ",othmask=%o", asb->s_other_mask);
 113         if (asb->s_ftsuffix != 0)
 114                 seq_printf(seq, ",ftsuffix=%u", asb->s_ftsuffix);
 115
 116         return 0;
 117 }
 118
 119 enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix};
 120
 121 static const struct fs_parameter_spec adfs_param_spec[] = {
 122         fsparam_uid     ("uid",         Opt_uid),
 123         fsparam_gid     ("gid",         Opt_gid),
 124         fsparam_u32oct  ("ownmask",     Opt_ownmask),
 125         fsparam_u32oct  ("othmask",     Opt_othmask),
 126         fsparam_u32     ("ftsuffix",    Opt_ftsuffix),
 127         {}
 128 };
 129
 130 static int adfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
 131 {
 132         struct adfs_sb_info *asb = fc->s_fs_info;
 133         struct fs_parse_result result;
 134         int opt;
 135
 136         opt = fs_parse(fc, adfs_param_spec, param, &result);
 137         if (opt < 0)
 138                 return opt;
 139
 140         switch (opt) {
 141         case Opt_uid:
 142                 asb->s_uid = result.uid;
 143                 break;
 144         case Opt_gid:
 145                 asb->s_gid = result.gid;
 146                 break;
 147         case Opt_ownmask:
 148                 asb->s_owner_mask = result.uint_32;
 149                 break;
 150         case Opt_othmask:
 151                 asb->s_other_mask = result.uint_32;
 152                 break;
 153         case Opt_ftsuffix:
 154                 asb->s_ftsuffix = result.uint_32;
 155                 break;
 156         default:
 157                 return -EINVAL;
 158         }
 159         return 0;
 160 }
 161
 162 static int adfs_reconfigure(struct fs_context *fc)
 163 {
 164         struct adfs_sb_info *new_asb = fc->s_fs_info;
 165         struct adfs_sb_info *asb = ADFS_SB(fc->root->d_sb);
 166
 167         sync_filesystem(fc->root->d_sb);
 168         fc->sb_flags |= ADFS_SB_FLAGS;
 169
 170         /* Structure copy newly parsed options */
 171         *asb = *new_asb;
 172
 173         return 0;
 174 }
 175
 176 static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 177 {
 178         struct super_block *sb = dentry->d_sb;
 179         struct adfs_sb_info *sbi = ADFS_SB(sb);
 180         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 181
 182         adfs_map_statfs(sb, buf);
 183
 184         buf->f_type    = ADFS_SUPER_MAGIC;
 185         buf->f_namelen = sbi->s_namelen;
 186         buf->f_bsize   = sb->s_blocksize;
 187         buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
 188         buf->f_fsid    = u64_to_fsid(id);
 189
 190         return 0;
 191 }
 192
 193 static struct kmem_cache *adfs_inode_cachep;
 194
 195 static struct inode *adfs_alloc_inode(struct super_block *sb)
 196 {
 197         struct adfs_inode_info *ei;
 198         ei = alloc_inode_sb(sb, adfs_inode_cachep, GFP_KERNEL);
 199         if (!ei)
 200                 return NULL;
 201         return &ei->vfs_inode;
 202 }
 203
 204 static void adfs_free_inode(struct inode *inode)
 205 {
 206         kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
 207 }
 208
 209 static int adfs_drop_inode(struct inode *inode)
 210 {
 211         /* always drop inodes if we are read-only */
 212         return !IS_ENABLED(CONFIG_ADFS_FS_RW) || IS_RDONLY(inode);
 213 }
 214
 215 static void init_once(void *foo)
 216 {
 217         struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
 218
 219         inode_init_once(&ei->vfs_inode);
 220 }
 221
 222 static int __init init_inodecache(void)
 223 {
 224         adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
 225                                              sizeof(struct adfs_inode_info),
 226                                              0, (SLAB_RECLAIM_ACCOUNT|
 227                                                 SLAB_ACCOUNT),
 228                                              init_once);
 229         if (adfs_inode_cachep == NULL)
 230                 return -ENOMEM;
 231         return 0;
 232 }
 233
 234 static void destroy_inodecache(void)
 235 {
 236         /*
 237          * Make sure all delayed rcu free inodes are flushed before we
 238          * destroy cache.
 239          */
 240         rcu_barrier();
 241         kmem_cache_destroy(adfs_inode_cachep);
 242 }
 243
 244 static const struct super_operations adfs_sops = {
 245         .alloc_inode    = adfs_alloc_inode,
 246         .free_inode     = adfs_free_inode,
 247         .drop_inode     = adfs_drop_inode,
 248         .write_inode    = adfs_write_inode,
 249         .put_super      = adfs_put_super,
 250         .statfs         = adfs_statfs,
 251         .show_options   = adfs_show_options,
 252 };
 253
 254 static int adfs_probe(struct super_block *sb, unsigned int offset, int silent,
 255                       int (*validate)(struct super_block *sb,
 256                                       struct buffer_head *bh,
 257                                       struct adfs_discrecord **bhp))
 258 {
 259         struct adfs_sb_info *asb = ADFS_SB(sb);
 260         struct adfs_discrecord *dr;
 261         struct buffer_head *bh;
 262         unsigned int blocksize = BLOCK_SIZE;
 263         int ret, try;
 264
 265         for (try = 0; try < 2; try++) {
 266                 /* try to set the requested block size */
 267                 if (sb->s_blocksize != blocksize &&
 268                     !sb_set_blocksize(sb, blocksize)) {
 269                         if (!silent)
 270                                 adfs_msg(sb, KERN_ERR,
 271                                          "error: unsupported blocksize");
 272                         return -EINVAL;
 273                 }
 274
 275                 /* read the buffer */
 276                 bh = sb_bread(sb, offset >> sb->s_blocksize_bits);
 277                 if (!bh) {
 278                         adfs_msg(sb, KERN_ERR,
 279                                  "error: unable to read block %u, try %d",
 280                                  offset >> sb->s_blocksize_bits, try);
 281                         return -EIO;
 282                 }
 283
 284                 /* validate it */
 285                 ret = validate(sb, bh, &dr);
 286                 if (ret) {
 287                         brelse(bh);
 288                         return ret;
 289                 }
 290
 291                 /* does the block size match the filesystem block size? */
 292                 blocksize = 1 << dr->log2secsize;
 293                 if (sb->s_blocksize == blocksize) {
 294                         asb->s_map = adfs_read_map(sb, dr);
 295                         brelse(bh);
 296                         return PTR_ERR_OR_ZERO(asb->s_map);
 297                 }
 298
 299                 brelse(bh);
 300         }
 301
 302         return -EIO;
 303 }
 304
 305 static int adfs_validate_bblk(struct super_block *sb, struct buffer_head *bh,
 306                               struct adfs_discrecord **drp)
 307 {
 308         struct adfs_discrecord *dr;
 309         unsigned char *b_data;
 310
 311         b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
 312         if (adfs_checkbblk(b_data))
 313                 return -EILSEQ;
 314
 315         /* Do some sanity checks on the ADFS disc record */
 316         dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
 317         if (adfs_checkdiscrecord(dr))
 318                 return -EILSEQ;
 319
 320         *drp = dr;
 321         return 0;
 322 }
 323
 324 static int adfs_validate_dr0(struct super_block *sb, struct buffer_head *bh,
 325                               struct adfs_discrecord **drp)
 326 {
 327         struct adfs_discrecord *dr;
 328
 329         /* Do some sanity checks on the ADFS disc record */
 330         dr = (struct adfs_discrecord *)(bh->b_data + 4);
 331         if (adfs_checkdiscrecord(dr) || dr->nzones_high || dr->nzones != 1)
 332                 return -EILSEQ;
 333
 334         *drp = dr;
 335         return 0;
 336 }
 337
 338 static int adfs_fill_super(struct super_block *sb, struct fs_context *fc)
 339 {
 340         struct adfs_discrecord *dr;
 341         struct object_info root_obj;
 342         struct adfs_sb_info *asb = sb->s_fs_info;
 343         struct inode *root;
 344         int ret = -EINVAL;
 345         int silent = fc->sb_flags & SB_SILENT;
 346
 347         sb->s_flags |= ADFS_SB_FLAGS;
 348
 349         sb->s_fs_info = asb;
 350         sb->s_magic = ADFS_SUPER_MAGIC;
 351         sb->s_time_gran = 10000000;
 352
 353         /* Try to probe the filesystem boot block */
 354         ret = adfs_probe(sb, ADFS_DISCRECORD, 1, adfs_validate_bblk);
 355         if (ret == -EILSEQ)
 356                 ret = adfs_probe(sb, 0, silent, adfs_validate_dr0);
 357         if (ret == -EILSEQ) {
 358                 if (!silent)
 359                         adfs_msg(sb, KERN_ERR,
 360                                  "error: can't find an ADFS filesystem on dev %s.",
 361                                  sb->s_id);
 362                 ret = -EINVAL;
 363         }
 364         if (ret)
 365                 goto error;
 366
 367         /* set up enough so that we can read an inode */
 368         sb->s_op = &adfs_sops;
 369
 370         dr = adfs_map_discrecord(asb->s_map);
 371
 372         root_obj.parent_id = root_obj.indaddr = le32_to_cpu(dr->root);
 373         root_obj.name_len  = 0;
 374         /* Set root object date as 01 Jan 1987 00:00:00 */
 375         root_obj.loadaddr  = 0xfff0003f;
 376         root_obj.execaddr  = 0xec22c000;
 377         root_obj.size      = ADFS_NEWDIR_SIZE;
 378         root_obj.attr      = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
 379                              ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
 380
 381         /*
 382          * If this is a F+ disk with variable length directories,
 383          * get the root_size from the disc record.
 384          */
 385         if (dr->format_version) {
 386                 root_obj.size = le32_to_cpu(dr->root_size);
 387                 asb->s_dir     = &adfs_fplus_dir_ops;
 388                 asb->s_namelen = ADFS_FPLUS_NAME_LEN;
 389         } else {
 390                 asb->s_dir     = &adfs_f_dir_ops;
 391                 asb->s_namelen = ADFS_F_NAME_LEN;
 392         }
 393         /*
 394          * ,xyz hex filetype suffix may be added by driver
 395          * to files that have valid RISC OS filetype
 396          */
 397         if (asb->s_ftsuffix)
 398                 asb->s_namelen += 4;
 399
 400         sb->s_d_op = &adfs_dentry_operations;
 401         root = adfs_iget(sb, &root_obj);
 402         sb->s_root = d_make_root(root);
 403         if (!sb->s_root) {
 404                 adfs_free_map(sb);
 405                 adfs_error(sb, "get root inode failed\n");
 406                 ret = -EIO;
 407                 goto error;
 408         }
 409         return 0;
 410
 411 error:
 412         sb->s_fs_info = NULL;
 413         kfree(asb);
 414         return ret;
 415 }
 416
 417 static int adfs_get_tree(struct fs_context *fc)
 418 {
 419         return get_tree_bdev(fc, adfs_fill_super);
 420 }
 421
 422 static void adfs_free_fc(struct fs_context *fc)
 423 {
 424         struct adfs_context *asb = fc->s_fs_info;
 425
 426         kfree(asb);
 427 }
 428
 429 static const struct fs_context_operations adfs_context_ops = {
 430         .parse_param    = adfs_parse_param,
 431         .get_tree       = adfs_get_tree,
 432         .reconfigure    = adfs_reconfigure,
 433         .free           = adfs_free_fc,
 434 };
 435
 436 static int adfs_init_fs_context(struct fs_context *fc)
 437 {
 438         struct adfs_sb_info *asb;
 439
 440         asb = kzalloc(sizeof(struct adfs_sb_info), GFP_KERNEL);
 441         if (!asb)
 442                 return -ENOMEM;
 443
 444         if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
 445                 struct super_block *sb = fc->root->d_sb;
 446                 struct adfs_sb_info *old_asb = ADFS_SB(sb);
 447
 448                 /* structure copy existing options before parsing */
 449                 *asb = *old_asb;
 450         } else {
 451                 /* set default options */
 452                 asb->s_uid = GLOBAL_ROOT_UID;
 453                 asb->s_gid = GLOBAL_ROOT_GID;
 454                 asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
 455                 asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
 456                 asb->s_ftsuffix = 0;
 457         }
 458
 459         fc->ops = &adfs_context_ops;
 460         fc->s_fs_info = asb;
 461
 462         return 0;
 463 }
 464
 465 static struct file_system_type adfs_fs_type = {
 466         .owner          = THIS_MODULE,
 467         .name           = "adfs",
 468         .kill_sb        = kill_block_super,
 469         .fs_flags       = FS_REQUIRES_DEV,
 470         .init_fs_context = adfs_init_fs_context,
 471         .parameters     = adfs_param_spec,
 472 };
 473 MODULE_ALIAS_FS("adfs");
 474
 475 static int __init init_adfs_fs(void)
 476 {
 477         int err = init_inodecache();
 478         if (err)
 479                 goto out1;
 480         err = register_filesystem(&adfs_fs_type);
 481         if (err)
 482                 goto out;
 483         return 0;
 484 out:
 485         destroy_inodecache();
 486 out1:
 487         return err;
 488 }
 489
 490 static void __exit exit_adfs_fs(void)
 491 {
 492         unregister_filesystem(&adfs_fs_type);
 493         destroy_inodecache();
 494 }
 495
 496 module_init(init_adfs_fs)
 497 module_exit(exit_adfs_fs)
 498 MODULE_DESCRIPTION("Acorn Disc Filing System");
 499 MODULE_LICENSE("GPL");