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         sb->s_dirt = 0;
  54
  55         /* sync everything to the buffers */
  56         hfs_mdb_commit(sb);
  57 }
  58
  59 static int hfs_sync_fs(struct super_block *sb, int wait)
  60 {
  61         hfs_mdb_commit(sb);
  62         sb->s_dirt = 0;
  63
  64         return 0;
  65 }
  66
  67 /*
  68  * hfs_put_super()
  69  *
  70  * This is the put_super() entry in the super_operations structure for
  71  * HFS filesystems.  The purpose is to release the resources
  72  * associated with the superblock sb.
  73  */
  74 static void hfs_put_super(struct super_block *sb)
  75 {
  76         hfs_mdb_close(sb);
  77         /* release the MDB's resources */
  78         hfs_mdb_put(sb);
  79 }
  80
  81 /*
  82  * hfs_statfs()
  83  *
  84  * This is the statfs() entry in the super_operations structure for
  85  * HFS filesystems.  The purpose is to return various data about the
  86  * filesystem.
  87  *
  88  * changed f_files/f_ffree to reflect the fs_ablock/free_ablocks.
  89  */
  90 static int hfs_statfs(struct dentry *dentry, struct kstatfs *buf)
  91 {
  92         struct super_block *sb = dentry->d_sb;
  93         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
  94
  95         buf->f_type = HFS_SUPER_MAGIC;
  96         buf->f_bsize = sb->s_blocksize;
  97         buf->f_blocks = (u32)HFS_SB(sb)->fs_ablocks * HFS_SB(sb)->fs_div;
  98         buf->f_bfree = (u32)HFS_SB(sb)->free_ablocks * HFS_SB(sb)->fs_div;
  99         buf->f_bavail = buf->f_bfree;
 100         buf->f_files = HFS_SB(sb)->fs_ablocks;
 101         buf->f_ffree = HFS_SB(sb)->free_ablocks;
 102         buf->f_fsid.val[0] = (u32)id;
 103         buf->f_fsid.val[1] = (u32)(id >> 32);
 104         buf->f_namelen = HFS_NAMELEN;
 105
 106         return 0;
 107 }
 108
 109 static int hfs_remount(struct super_block *sb, int *flags, char *data)
 110 {
 111         *flags |= MS_NODIRATIME;
 112         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 113                 return 0;
 114         if (!(*flags & MS_RDONLY)) {
 115                 if (!(HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
 116                         printk(KERN_WARNING "hfs: filesystem was not cleanly unmounted, "
 117                                "running fsck.hfs is recommended.  leaving read-only.\n");
 118                         sb->s_flags |= MS_RDONLY;
 119                         *flags |= MS_RDONLY;
 120                 } else if (HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_SLOCK)) {
 121                         printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
 122                         sb->s_flags |= MS_RDONLY;
 123                         *flags |= MS_RDONLY;
 124                 }
 125         }
 126         return 0;
 127 }
 128
 129 static int hfs_show_options(struct seq_file *seq, struct dentry *root)
 130 {
 131         struct hfs_sb_info *sbi = HFS_SB(root->d_sb);
 132
 133         if (sbi->s_creator != cpu_to_be32(0x3f3f3f3f))
 134                 seq_printf(seq, ",creator=%.4s", (char *)&sbi->s_creator);
 135         if (sbi->s_type != cpu_to_be32(0x3f3f3f3f))
 136                 seq_printf(seq, ",type=%.4s", (char *)&sbi->s_type);
 137         seq_printf(seq, ",uid=%u,gid=%u", sbi->s_uid, sbi->s_gid);
 138         if (sbi->s_file_umask != 0133)
 139                 seq_printf(seq, ",file_umask=%o", sbi->s_file_umask);
 140         if (sbi->s_dir_umask != 0022)
 141                 seq_printf(seq, ",dir_umask=%o", sbi->s_dir_umask);
 142         if (sbi->part >= 0)
 143                 seq_printf(seq, ",part=%u", sbi->part);
 144         if (sbi->session >= 0)
 145                 seq_printf(seq, ",session=%u", sbi->session);
 146         if (sbi->nls_disk)
 147                 seq_printf(seq, ",codepage=%s", sbi->nls_disk->charset);
 148         if (sbi->nls_io)
 149                 seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
 150         if (sbi->s_quiet)
 151                 seq_printf(seq, ",quiet");
 152         return 0;
 153 }
 154
 155 static struct inode *hfs_alloc_inode(struct super_block *sb)
 156 {
 157         struct hfs_inode_info *i;
 158
 159         i = kmem_cache_alloc(hfs_inode_cachep, GFP_KERNEL);
 160         return i ? &i->vfs_inode : NULL;
 161 }
 162
 163 static void hfs_i_callback(struct rcu_head *head)
 164 {
 165         struct inode *inode = container_of(head, struct inode, i_rcu);
 166         kmem_cache_free(hfs_inode_cachep, HFS_I(inode));
 167 }
 168
 169 static void hfs_destroy_inode(struct inode *inode)
 170 {
 171         call_rcu(&inode->i_rcu, hfs_i_callback);
 172 }
 173
 174 static const struct super_operations hfs_super_operations = {
 175         .alloc_inode    = hfs_alloc_inode,
 176         .destroy_inode  = hfs_destroy_inode,
 177         .write_inode    = hfs_write_inode,
 178         .evict_inode    = hfs_evict_inode,
 179         .put_super      = hfs_put_super,
 180         .write_super    = hfs_write_super,
 181         .sync_fs        = hfs_sync_fs,
 182         .statfs         = hfs_statfs,
 183         .remount_fs     = hfs_remount,
 184         .show_options   = hfs_show_options,
 185 };
 186
 187 enum {
 188         opt_uid, opt_gid, opt_umask, opt_file_umask, opt_dir_umask,
 189         opt_part, opt_session, opt_type, opt_creator, opt_quiet,
 190         opt_codepage, opt_iocharset,
 191         opt_err
 192 };
 193
 194 static const match_table_t tokens = {
 195         { opt_uid, "uid=%u" },
 196         { opt_gid, "gid=%u" },
 197         { opt_umask, "umask=%o" },
 198         { opt_file_umask, "file_umask=%o" },
 199         { opt_dir_umask, "dir_umask=%o" },
 200         { opt_part, "part=%u" },
 201         { opt_session, "session=%u" },
 202         { opt_type, "type=%s" },
 203         { opt_creator, "creator=%s" },
 204         { opt_quiet, "quiet" },
 205         { opt_codepage, "codepage=%s" },
 206         { opt_iocharset, "iocharset=%s" },
 207         { opt_err, NULL }
 208 };
 209
 210 static inline int match_fourchar(substring_t *arg, u32 *result)
 211 {
 212         if (arg->to - arg->from != 4)
 213                 return -EINVAL;
 214         memcpy(result, arg->from, 4);
 215         return 0;
 216 }
 217
 218 /*
 219  * parse_options()
 220  *
 221  * adapted from linux/fs/msdos/inode.c written 1992,93 by Werner Almesberger
 222  * This function is called by hfs_read_super() to parse the mount options.
 223  */
 224 static int parse_options(char *options, struct hfs_sb_info *hsb)
 225 {
 226         char *p;
 227         substring_t args[MAX_OPT_ARGS];
 228         int tmp, token;
 229
 230         /* initialize the sb with defaults */
 231         hsb->s_uid = current_uid();
 232         hsb->s_gid = current_gid();
 233         hsb->s_file_umask = 0133;
 234         hsb->s_dir_umask = 0022;
 235         hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f); /* == '????' */
 236         hsb->s_quiet = 0;
 237         hsb->part = -1;
 238         hsb->session = -1;
 239
 240         if (!options)
 241                 return 1;
 242
 243         while ((p = strsep(&options, ",")) != NULL) {
 244                 if (!*p)
 245                         continue;
 246
 247                 token = match_token(p, tokens, args);
 248                 switch (token) {
 249                 case opt_uid:
 250                         if (match_int(&args[0], &tmp)) {
 251                                 printk(KERN_ERR "hfs: uid requires an argument\n");
 252                                 return 0;
 253                         }
 254                         hsb->s_uid = (uid_t)tmp;
 255                         break;
 256                 case opt_gid:
 257                         if (match_int(&args[0], &tmp)) {
 258                                 printk(KERN_ERR "hfs: gid requires an argument\n");
 259                                 return 0;
 260                         }
 261                         hsb->s_gid = (gid_t)tmp;
 262                         break;
 263                 case opt_umask:
 264                         if (match_octal(&args[0], &tmp)) {
 265                                 printk(KERN_ERR "hfs: umask requires a value\n");
 266                                 return 0;
 267                         }
 268                         hsb->s_file_umask = (umode_t)tmp;
 269                         hsb->s_dir_umask = (umode_t)tmp;
 270                         break;
 271                 case opt_file_umask:
 272                         if (match_octal(&args[0], &tmp)) {
 273                                 printk(KERN_ERR "hfs: file_umask requires a value\n");
 274                                 return 0;
 275                         }
 276                         hsb->s_file_umask = (umode_t)tmp;
 277                         break;
 278                 case opt_dir_umask:
 279                         if (match_octal(&args[0], &tmp)) {
 280                                 printk(KERN_ERR "hfs: dir_umask requires a value\n");
 281                                 return 0;
 282                         }
 283                         hsb->s_dir_umask = (umode_t)tmp;
 284                         break;
 285                 case opt_part:
 286                         if (match_int(&args[0], &hsb->part)) {
 287                                 printk(KERN_ERR "hfs: part requires an argument\n");
 288                                 return 0;
 289                         }
 290                         break;
 291                 case opt_session:
 292                         if (match_int(&args[0], &hsb->session)) {
 293                                 printk(KERN_ERR "hfs: session requires an argument\n");
 294                                 return 0;
 295                         }
 296                         break;
 297                 case opt_type:
 298                         if (match_fourchar(&args[0], &hsb->s_type)) {
 299                                 printk(KERN_ERR "hfs: type requires a 4 character value\n");
 300                                 return 0;
 301                         }
 302                         break;
 303                 case opt_creator:
 304                         if (match_fourchar(&args[0], &hsb->s_creator)) {
 305                                 printk(KERN_ERR "hfs: creator requires a 4 character value\n");
 306                                 return 0;
 307                         }
 308                         break;
 309                 case opt_quiet:
 310                         hsb->s_quiet = 1;
 311                         break;
 312                 case opt_codepage:
 313                         if (hsb->nls_disk) {
 314                                 printk(KERN_ERR "hfs: unable to change codepage\n");
 315                                 return 0;
 316                         }
 317                         p = match_strdup(&args[0]);
 318                         if (p)
 319                                 hsb->nls_disk = load_nls(p);
 320                         if (!hsb->nls_disk) {
 321                                 printk(KERN_ERR "hfs: unable to load codepage \"%s\"\n", p);
 322                                 kfree(p);
 323                                 return 0;
 324                         }
 325                         kfree(p);
 326                         break;
 327                 case opt_iocharset:
 328                         if (hsb->nls_io) {
 329                                 printk(KERN_ERR "hfs: unable to change iocharset\n");
 330                                 return 0;
 331                         }
 332                         p = match_strdup(&args[0]);
 333                         if (p)
 334                                 hsb->nls_io = load_nls(p);
 335                         if (!hsb->nls_io) {
 336                                 printk(KERN_ERR "hfs: unable to load iocharset \"%s\"\n", p);
 337                                 kfree(p);
 338                                 return 0;
 339                         }
 340                         kfree(p);
 341                         break;
 342                 default:
 343                         return 0;
 344                 }
 345         }
 346
 347         if (hsb->nls_disk && !hsb->nls_io) {
 348                 hsb->nls_io = load_nls_default();
 349                 if (!hsb->nls_io) {
 350                         printk(KERN_ERR "hfs: unable to load default iocharset\n");
 351                         return 0;
 352                 }
 353         }
 354         hsb->s_dir_umask &= 0777;
 355         hsb->s_file_umask &= 0577;
 356
 357         return 1;
 358 }
 359
 360 /*
 361  * hfs_read_super()
 362  *
 363  * This is the function that is responsible for mounting an HFS
 364  * filesystem.  It performs all the tasks necessary to get enough data
 365  * from the disk to read the root inode.  This includes parsing the
 366  * mount options, dealing with Macintosh partitions, reading the
 367  * superblock and the allocation bitmap blocks, calling
 368  * hfs_btree_init() to get the necessary data about the extents and
 369  * catalog B-trees and, finally, reading the root inode into memory.
 370  */
 371 static int hfs_fill_super(struct super_block *sb, void *data, int silent)
 372 {
 373         struct hfs_sb_info *sbi;
 374         struct hfs_find_data fd;
 375         hfs_cat_rec rec;
 376         struct inode *root_inode;
 377         int res;
 378
 379         sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
 380         if (!sbi)
 381                 return -ENOMEM;
 382
 383         sbi->sb = sb;
 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         sb->s_d_op = &hfs_dentry_operations;
 426         res = -ENOMEM;
 427         sb->s_root = d_make_root(root_inode);
 428         if (!sb->s_root)
 429                 goto bail_no_root;
 430
 431         /* everything's okay */
 432         return 0;
 433
 434 bail_no_root:
 435         printk(KERN_ERR "hfs: get root inode failed.\n");
 436 bail:
 437         hfs_mdb_put(sb);
 438         return res;
 439 }
 440
 441 static struct dentry *hfs_mount(struct file_system_type *fs_type,
 442                       int flags, const char *dev_name, void *data)
 443 {
 444         return mount_bdev(fs_type, flags, dev_name, data, hfs_fill_super);
 445 }
 446
 447 static struct file_system_type hfs_fs_type = {
 448         .owner          = THIS_MODULE,
 449         .name           = "hfs",
 450         .mount          = hfs_mount,
 451         .kill_sb        = kill_block_super,
 452         .fs_flags       = FS_REQUIRES_DEV,
 453 };
 454
 455 static void hfs_init_once(void *p)
 456 {
 457         struct hfs_inode_info *i = p;
 458
 459         inode_init_once(&i->vfs_inode);
 460 }
 461
 462 static int __init init_hfs_fs(void)
 463 {
 464         int err;
 465
 466         hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
 467                 sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
 468                 hfs_init_once);
 469         if (!hfs_inode_cachep)
 470                 return -ENOMEM;
 471         err = register_filesystem(&hfs_fs_type);
 472         if (err)
 473                 kmem_cache_destroy(hfs_inode_cachep);
 474         return err;
 475 }
 476
 477 static void __exit exit_hfs_fs(void)
 478 {
 479         unregister_filesystem(&hfs_fs_type);
 480         kmem_cache_destroy(hfs_inode_cachep);
 481 }
 482
 483 module_init(init_hfs_fs)
 484 module_exit(exit_hfs_fs)