fs/hfs/super.c

   1 /*
   2  *  linux/fs/hfs/super.c
   3  *
   4  * Copyright (C) 1995-1997  Paul H. Hargrove
   5  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   6  * This file may be distributed under the terms of the GNU General Public License.
   7  *
   8  * This file contains hfs_read_super(), some of the super_ops and
   9  * init_hfs_fs() and exit_hfs_fs().  The remaining super_ops are in
  10  * inode.c since they deal with inodes.
  11  *
  12  * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/blkdev.h>
  17 #include <linux/mount.h>
  18 #include <linux/init.h>
  19 #include <linux/nls.h>
  20 #include <linux/parser.h>
  21 #include <linux/seq_file.h>
  22 #include <linux/slab.h>
  23 #include <linux/vfs.h>
  24
  25 #include "hfs_fs.h"
  26 #include "btree.h"
  27
  28 static struct kmem_cache *hfs_inode_cachep;
  29
  30 MODULE_LICENSE("GPL");
  31
  32 /*
  33  * hfs_write_super()
  34  *
  35  * Description:
  36  *   This function is called by the VFS only. When the filesystem
  37  *   is mounted r/w it updates the MDB on disk.
  38  * Input Variable(s):
  39  *   struct super_block *sb: Pointer to the hfs superblock
  40  * Output Variable(s):
  41  *   NONE
  42  * Returns:
  43  *   void
  44  * Preconditions:
  45  *   'sb' points to a "valid" (struct super_block).
  46  * Postconditions:
  47  *   The MDB is marked 'unsuccessfully unmounted' by clearing bit 8 of drAtrb
  48  *   (hfs_put_super() must set this flag!). Some MDB fields are updated
  49  *   and the MDB buffer is written to disk by calling hfs_mdb_commit().
  50  */
  51 static void hfs_write_super(struct super_block *sb)
  52 {
  53         lock_super(sb);
  54         sb->s_dirt = 0;
  55
  56         /* sync everything to the buffers */
  57         if (!(sb->s_flags & MS_RDONLY))
  58                 hfs_mdb_commit(sb);
  59         unlock_super(sb);
  60 }
  61
  62 static int hfs_sync_fs(struct super_block *sb, int wait)
  63 {
  64         lock_super(sb);
  65         hfs_mdb_commit(sb);
  66         sb->s_dirt = 0;
  67         unlock_super(sb);
  68
  69         return 0;
  70 }
  71
  72 /*
  73  * hfs_put_super()
  74  *
  75  * This is the put_super() entry in the super_operations structure for
  76  * HFS filesystems.  The purpose is to release the resources
  77  * associated with the superblock sb.
  78  */
  79 static void hfs_put_super(struct super_block *sb)
  80 {
  81         if (sb->s_dirt)
  82                 hfs_write_super(sb);
  83         hfs_mdb_close(sb);
  84         /* release the MDB's resources */
  85         hfs_mdb_put(sb);
  86 }
  87
  88 /*
  89  * hfs_statfs()
  90  *
  91  * This is the statfs() entry in the super_operations structure for
  92  * HFS filesystems.  The purpose is to return various data about the
  93  * filesystem.
  94  *
  95  * changed f_files/f_ffree to reflect the fs_ablock/free_ablocks.
  96  */
  97 static int hfs_statfs(struct dentry *dentry, struct kstatfs *buf)
  98 {
  99         struct super_block *sb = dentry->d_sb;
 100         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 101
 102         buf->f_type = HFS_SUPER_MAGIC;
 103         buf->f_bsize = sb->s_blocksize;
 104         buf->f_blocks = (u32)HFS_SB(sb)->fs_ablocks * HFS_SB(sb)->fs_div;
 105         buf->f_bfree = (u32)HFS_SB(sb)->free_ablocks * HFS_SB(sb)->fs_div;
 106         buf->f_bavail = buf->f_bfree;
 107         buf->f_files = HFS_SB(sb)->fs_ablocks;
 108         buf->f_ffree = HFS_SB(sb)->free_ablocks;
 109         buf->f_fsid.val[0] = (u32)id;
 110         buf->f_fsid.val[1] = (u32)(id >> 32);
 111         buf->f_namelen = HFS_NAMELEN;
 112
 113         return 0;
 114 }
 115
 116 static int hfs_remount(struct super_block *sb, int *flags, char *data)
 117 {
 118         *flags |= MS_NODIRATIME;
 119         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 120                 return 0;
 121         if (!(*flags & MS_RDONLY)) {
 122                 if (!(HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
 123                         printk(KERN_WARNING "hfs: filesystem was not cleanly unmounted, "
 124                                "running fsck.hfs is recommended.  leaving read-only.\n");
 125                         sb->s_flags |= MS_RDONLY;
 126                         *flags |= MS_RDONLY;
 127                 } else if (HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_SLOCK)) {
 128                         printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
 129                         sb->s_flags |= MS_RDONLY;
 130                         *flags |= MS_RDONLY;
 131                 }
 132         }
 133         return 0;
 134 }
 135
 136 static int hfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
 137 {
 138         struct hfs_sb_info *sbi = HFS_SB(mnt->mnt_sb);
 139
 140         if (sbi->s_creator != cpu_to_be32(0x3f3f3f3f))
 141                 seq_printf(seq, ",creator=%.4s", (char *)&sbi->s_creator);
 142         if (sbi->s_type != cpu_to_be32(0x3f3f3f3f))
 143                 seq_printf(seq, ",type=%.4s", (char *)&sbi->s_type);
 144         seq_printf(seq, ",uid=%u,gid=%u", sbi->s_uid, sbi->s_gid);
 145         if (sbi->s_file_umask != 0133)
 146                 seq_printf(seq, ",file_umask=%o", sbi->s_file_umask);
 147         if (sbi->s_dir_umask != 0022)
 148                 seq_printf(seq, ",dir_umask=%o", sbi->s_dir_umask);
 149         if (sbi->part >= 0)
 150                 seq_printf(seq, ",part=%u", sbi->part);
 151         if (sbi->session >= 0)
 152                 seq_printf(seq, ",session=%u", sbi->session);
 153         if (sbi->nls_disk)
 154                 seq_printf(seq, ",codepage=%s", sbi->nls_disk->charset);
 155         if (sbi->nls_io)
 156                 seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
 157         if (sbi->s_quiet)
 158                 seq_printf(seq, ",quiet");
 159         return 0;
 160 }
 161
 162 static struct inode *hfs_alloc_inode(struct super_block *sb)
 163 {
 164         struct hfs_inode_info *i;
 165
 166         i = kmem_cache_alloc(hfs_inode_cachep, GFP_KERNEL);
 167         return i ? &i->vfs_inode : NULL;
 168 }
 169
 170 static void hfs_destroy_inode(struct inode *inode)
 171 {
 172         kmem_cache_free(hfs_inode_cachep, HFS_I(inode));
 173 }
 174
 175 static const struct super_operations hfs_super_operations = {
 176         .alloc_inode    = hfs_alloc_inode,
 177         .destroy_inode  = hfs_destroy_inode,
 178         .write_inode    = hfs_write_inode,
 179         .evict_inode    = hfs_evict_inode,
 180         .put_super      = hfs_put_super,
 181         .write_super    = hfs_write_super,
 182         .sync_fs        = hfs_sync_fs,
 183         .statfs         = hfs_statfs,
 184         .remount_fs     = hfs_remount,
 185         .show_options   = hfs_show_options,
 186 };
 187
 188 enum {
 189         opt_uid, opt_gid, opt_umask, opt_file_umask, opt_dir_umask,
 190         opt_part, opt_session, opt_type, opt_creator, opt_quiet,
 191         opt_codepage, opt_iocharset,
 192         opt_err
 193 };
 194
 195 static const match_table_t tokens = {
 196         { opt_uid, "uid=%u" },
 197         { opt_gid, "gid=%u" },
 198         { opt_umask, "umask=%o" },
 199         { opt_file_umask, "file_umask=%o" },
 200         { opt_dir_umask, "dir_umask=%o" },
 201         { opt_part, "part=%u" },
 202         { opt_session, "session=%u" },
 203         { opt_type, "type=%s" },
 204         { opt_creator, "creator=%s" },
 205         { opt_quiet, "quiet" },
 206         { opt_codepage, "codepage=%s" },
 207         { opt_iocharset, "iocharset=%s" },
 208         { opt_err, NULL }
 209 };
 210
 211 static inline int match_fourchar(substring_t *arg, u32 *result)
 212 {
 213         if (arg->to - arg->from != 4)
 214                 return -EINVAL;
 215         memcpy(result, arg->from, 4);
 216         return 0;
 217 }
 218
 219 /*
 220  * parse_options()
 221  *
 222  * adapted from linux/fs/msdos/inode.c written 1992,93 by Werner Almesberger
 223  * This function is called by hfs_read_super() to parse the mount options.
 224  */
 225 static int parse_options(char *options, struct hfs_sb_info *hsb)
 226 {
 227         char *p;
 228         substring_t args[MAX_OPT_ARGS];
 229         int tmp, token;
 230
 231         /* initialize the sb with defaults */
 232         hsb->s_uid = current_uid();
 233         hsb->s_gid = current_gid();
 234         hsb->s_file_umask = 0133;
 235         hsb->s_dir_umask = 0022;
 236         hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f); /* == '????' */
 237         hsb->s_quiet = 0;
 238         hsb->part = -1;
 239         hsb->session = -1;
 240
 241         if (!options)
 242                 return 1;
 243
 244         while ((p = strsep(&options, ",")) != NULL) {
 245                 if (!*p)
 246                         continue;
 247
 248                 token = match_token(p, tokens, args);
 249                 switch (token) {
 250                 case opt_uid:
 251                         if (match_int(&args[0], &tmp)) {
 252                                 printk(KERN_ERR "hfs: uid requires an argument\n");
 253                                 return 0;
 254                         }
 255                         hsb->s_uid = (uid_t)tmp;
 256                         break;
 257                 case opt_gid:
 258                         if (match_int(&args[0], &tmp)) {
 259                                 printk(KERN_ERR "hfs: gid requires an argument\n");
 260                                 return 0;
 261                         }
 262                         hsb->s_gid = (gid_t)tmp;
 263                         break;
 264                 case opt_umask:
 265                         if (match_octal(&args[0], &tmp)) {
 266                                 printk(KERN_ERR "hfs: umask requires a value\n");
 267                                 return 0;
 268                         }
 269                         hsb->s_file_umask = (umode_t)tmp;
 270                         hsb->s_dir_umask = (umode_t)tmp;
 271                         break;
 272                 case opt_file_umask:
 273                         if (match_octal(&args[0], &tmp)) {
 274                                 printk(KERN_ERR "hfs: file_umask requires a value\n");
 275                                 return 0;
 276                         }
 277                         hsb->s_file_umask = (umode_t)tmp;
 278                         break;
 279                 case opt_dir_umask:
 280                         if (match_octal(&args[0], &tmp)) {
 281                                 printk(KERN_ERR "hfs: dir_umask requires a value\n");
 282                                 return 0;
 283                         }
 284                         hsb->s_dir_umask = (umode_t)tmp;
 285                         break;
 286                 case opt_part:
 287                         if (match_int(&args[0], &hsb->part)) {
 288                                 printk(KERN_ERR "hfs: part requires an argument\n");
 289                                 return 0;
 290                         }
 291                         break;
 292                 case opt_session:
 293                         if (match_int(&args[0], &hsb->session)) {
 294                                 printk(KERN_ERR "hfs: session requires an argument\n");
 295                                 return 0;
 296                         }
 297                         break;
 298                 case opt_type:
 299                         if (match_fourchar(&args[0], &hsb->s_type)) {
 300                                 printk(KERN_ERR "hfs: type requires a 4 character value\n");
 301                                 return 0;
 302                         }
 303                         break;
 304                 case opt_creator:
 305                         if (match_fourchar(&args[0], &hsb->s_creator)) {
 306                                 printk(KERN_ERR "hfs: creator requires a 4 character value\n");
 307                                 return 0;
 308                         }
 309                         break;
 310                 case opt_quiet:
 311                         hsb->s_quiet = 1;
 312                         break;
 313                 case opt_codepage:
 314                         if (hsb->nls_disk) {
 315                                 printk(KERN_ERR "hfs: unable to change codepage\n");
 316                                 return 0;
 317                         }
 318                         p = match_strdup(&args[0]);
 319                         if (p)
 320                                 hsb->nls_disk = load_nls(p);
 321                         if (!hsb->nls_disk) {
 322                                 printk(KERN_ERR "hfs: unable to load codepage \"%s\"\n", p);
 323                                 kfree(p);
 324                                 return 0;
 325                         }
 326                         kfree(p);
 327                         break;
 328                 case opt_iocharset:
 329                         if (hsb->nls_io) {
 330                                 printk(KERN_ERR "hfs: unable to change iocharset\n");
 331                                 return 0;
 332                         }
 333                         p = match_strdup(&args[0]);
 334                         if (p)
 335                                 hsb->nls_io = load_nls(p);
 336                         if (!hsb->nls_io) {
 337                                 printk(KERN_ERR "hfs: unable to load iocharset \"%s\"\n", p);
 338                                 kfree(p);
 339                                 return 0;
 340                         }
 341                         kfree(p);
 342                         break;
 343                 default:
 344                         return 0;
 345                 }
 346         }
 347
 348         if (hsb->nls_disk && !hsb->nls_io) {
 349                 hsb->nls_io = load_nls_default();
 350                 if (!hsb->nls_io) {
 351                         printk(KERN_ERR "hfs: unable to load default iocharset\n");
 352                         return 0;
 353                 }
 354         }
 355         hsb->s_dir_umask &= 0777;
 356         hsb->s_file_umask &= 0577;
 357
 358         return 1;
 359 }
 360
 361 /*
 362  * hfs_read_super()
 363  *
 364  * This is the function that is responsible for mounting an HFS
 365  * filesystem.  It performs all the tasks necessary to get enough data
 366  * from the disk to read the root inode.  This includes parsing the
 367  * mount options, dealing with Macintosh partitions, reading the
 368  * superblock and the allocation bitmap blocks, calling
 369  * hfs_btree_init() to get the necessary data about the extents and
 370  * catalog B-trees and, finally, reading the root inode into memory.
 371  */
 372 static int hfs_fill_super(struct super_block *sb, void *data, int silent)
 373 {
 374         struct hfs_sb_info *sbi;
 375         struct hfs_find_data fd;
 376         hfs_cat_rec rec;
 377         struct inode *root_inode;
 378         int res;
 379
 380         sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
 381         if (!sbi)
 382                 return -ENOMEM;
 383
 384         sb->s_fs_info = sbi;
 385
 386         res = -EINVAL;
 387         if (!parse_options((char *)data, sbi)) {
 388                 printk(KERN_ERR "hfs: unable to parse mount options.\n");
 389                 goto bail;
 390         }
 391
 392         sb->s_op = &hfs_super_operations;
 393         sb->s_flags |= MS_NODIRATIME;
 394         mutex_init(&sbi->bitmap_lock);
 395
 396         res = hfs_mdb_get(sb);
 397         if (res) {
 398                 if (!silent)
 399                         printk(KERN_WARNING "hfs: can't find a HFS filesystem on dev %s.\n",
 400                                 hfs_mdb_name(sb));
 401                 res = -EINVAL;
 402                 goto bail;
 403         }
 404
 405         /* try to get the root inode */
 406         hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
 407         res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
 408         if (!res) {
 409                 if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
 410                         res =  -EIO;
 411                         goto bail;
 412                 }
 413                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
 414         }
 415         if (res) {
 416                 hfs_find_exit(&fd);
 417                 goto bail_no_root;
 418         }
 419         res = -EINVAL;
 420         root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
 421         hfs_find_exit(&fd);
 422         if (!root_inode)
 423                 goto bail_no_root;
 424
 425         res = -ENOMEM;
 426         sb->s_root = d_alloc_root(root_inode);
 427         if (!sb->s_root)
 428                 goto bail_iput;
 429
 430         sb->s_root->d_op = &hfs_dentry_operations;
 431
 432         /* everything's okay */
 433         return 0;
 434
 435 bail_iput:
 436         iput(root_inode);
 437 bail_no_root:
 438         printk(KERN_ERR "hfs: get root inode failed.\n");
 439 bail:
 440         hfs_mdb_put(sb);
 441         return res;
 442 }
 443
 444 static int hfs_get_sb(struct file_system_type *fs_type,
 445                       int flags, const char *dev_name, void *data,
 446                       struct vfsmount *mnt)
 447 {
 448         return get_sb_bdev(fs_type, flags, dev_name, data, hfs_fill_super, mnt);
 449 }
 450
 451 static struct file_system_type hfs_fs_type = {
 452         .owner          = THIS_MODULE,
 453         .name           = "hfs",
 454         .get_sb         = hfs_get_sb,
 455         .kill_sb        = kill_block_super,
 456         .fs_flags       = FS_REQUIRES_DEV,
 457 };
 458
 459 static void hfs_init_once(void *p)
 460 {
 461         struct hfs_inode_info *i = p;
 462
 463         inode_init_once(&i->vfs_inode);
 464 }
 465
 466 static int __init init_hfs_fs(void)
 467 {
 468         int err;
 469
 470         hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
 471                 sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
 472                 hfs_init_once);
 473         if (!hfs_inode_cachep)
 474                 return -ENOMEM;
 475         err = register_filesystem(&hfs_fs_type);
 476         if (err)
 477                 kmem_cache_destroy(hfs_inode_cachep);
 478         return err;
 479 }
 480
 481 static void __exit exit_hfs_fs(void)
 482 {
 483         unregister_filesystem(&hfs_fs_type);
 484         kmem_cache_destroy(hfs_inode_cachep);
 485 }
 486
 487 module_init(init_hfs_fs)
 488 module_exit(exit_hfs_fs)