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