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_module() and cleanup_module().  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/config.h>
  16 #include <linux/module.h>
  17 #include <linux/blkdev.h>
  18 #include <linux/init.h>
  19 #include <linux/parser.h>
  20 #include <linux/vfs.h>
  21
  22 #include "hfs_fs.h"
  23 #include "btree.h"
  24
  25 static kmem_cache_t *hfs_inode_cachep;
  26
  27 MODULE_LICENSE("GPL");
  28
  29 /*
  30  * hfs_write_super()
  31  *
  32  * Description:
  33  *   This function is called by the VFS only. When the filesystem
  34  *   is mounted r/w it updates the MDB on disk.
  35  * Input Variable(s):
  36  *   struct super_block *sb: Pointer to the hfs superblock
  37  * Output Variable(s):
  38  *   NONE
  39  * Returns:
  40  *   void
  41  * Preconditions:
  42  *   'sb' points to a "valid" (struct super_block).
  43  * Postconditions:
  44  *   The MDB is marked 'unsuccessfully unmounted' by clearing bit 8 of drAtrb
  45  *   (hfs_put_super() must set this flag!). Some MDB fields are updated
  46  *   and the MDB buffer is written to disk by calling hfs_mdb_commit().
  47  */
  48 static void hfs_write_super(struct super_block *sb)
  49 {
  50         sb->s_dirt = 0;
  51         if (sb->s_flags & MS_RDONLY)
  52                 return;
  53         /* sync everything to the buffers */
  54         hfs_mdb_commit(sb);
  55 }
  56
  57 /*
  58  * hfs_put_super()
  59  *
  60  * This is the put_super() entry in the super_operations structure for
  61  * HFS filesystems.  The purpose is to release the resources
  62  * associated with the superblock sb.
  63  */
  64 static void hfs_put_super(struct super_block *sb)
  65 {
  66         hfs_mdb_close(sb);
  67         /* release the MDB's resources */
  68         hfs_mdb_put(sb);
  69 }
  70
  71 /*
  72  * hfs_statfs()
  73  *
  74  * This is the statfs() entry in the super_operations structure for
  75  * HFS filesystems.  The purpose is to return various data about the
  76  * filesystem.
  77  *
  78  * changed f_files/f_ffree to reflect the fs_ablock/free_ablocks.
  79  */
  80 static int hfs_statfs(struct super_block *sb, struct kstatfs *buf)
  81 {
  82         buf->f_type = HFS_SUPER_MAGIC;
  83         buf->f_bsize = sb->s_blocksize;
  84         buf->f_blocks = (u32)HFS_SB(sb)->fs_ablocks * HFS_SB(sb)->fs_div;
  85         buf->f_bfree = (u32)HFS_SB(sb)->free_ablocks * HFS_SB(sb)->fs_div;
  86         buf->f_bavail = buf->f_bfree;
  87         buf->f_files = HFS_SB(sb)->fs_ablocks;
  88         buf->f_ffree = HFS_SB(sb)->free_ablocks;
  89         buf->f_namelen = HFS_NAMELEN;
  90
  91         return 0;
  92 }
  93
  94 static int hfs_remount(struct super_block *sb, int *flags, char *data)
  95 {
  96         *flags |= MS_NODIRATIME;
  97         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
  98                 return 0;
  99         if (!(*flags & MS_RDONLY)) {
 100                 if (!(HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
 101                         printk("HFS-fs warning: Filesystem was not cleanly unmounted, "
 102                                "running fsck.hfs is recommended.  leaving read-only.\n");
 103                         sb->s_flags |= MS_RDONLY;
 104                         *flags |= MS_RDONLY;
 105                 } else if (HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_SLOCK)) {
 106                         printk("HFS-fs: Filesystem is marked locked, leaving read-only.\n");
 107                         sb->s_flags |= MS_RDONLY;
 108                         *flags |= MS_RDONLY;
 109                 }
 110         }
 111         return 0;
 112 }
 113
 114 static struct inode *hfs_alloc_inode(struct super_block *sb)
 115 {
 116         struct hfs_inode_info *i;
 117
 118         i = kmem_cache_alloc(hfs_inode_cachep, SLAB_KERNEL);
 119         return i ? &i->vfs_inode : NULL;
 120 }
 121
 122 static void hfs_destroy_inode(struct inode *inode)
 123 {
 124         kmem_cache_free(hfs_inode_cachep, HFS_I(inode));
 125 }
 126
 127 static struct super_operations hfs_super_operations = {
 128         .alloc_inode    = hfs_alloc_inode,
 129         .destroy_inode  = hfs_destroy_inode,
 130         .write_inode    = hfs_write_inode,
 131         .clear_inode    = hfs_clear_inode,
 132         .put_super      = hfs_put_super,
 133         .write_super    = hfs_write_super,
 134         .statfs         = hfs_statfs,
 135         .remount_fs     = hfs_remount,
 136 };
 137
 138 enum {
 139         opt_uid, opt_gid, opt_umask, opt_file_umask, opt_dir_umask,
 140         opt_part, opt_session, opt_type, opt_creator, opt_quiet,
 141         opt_err
 142 };
 143
 144 static match_table_t tokens = {
 145         { opt_uid, "uid=%u" },
 146         { opt_gid, "gid=%u" },
 147         { opt_umask, "umask=%o" },
 148         { opt_file_umask, "file_umask=%o" },
 149         { opt_dir_umask, "dir_umask=%o" },
 150         { opt_part, "part=%u" },
 151         { opt_session, "session=%u" },
 152         { opt_type, "type=%s" },
 153         { opt_creator, "creator=%s" },
 154         { opt_quiet, "quiet" },
 155         { opt_err, NULL }
 156 };
 157
 158 static inline int match_fourchar(substring_t *arg, u32 *result)
 159 {
 160         if (arg->to - arg->from != 4)
 161                 return -EINVAL;
 162         memcpy(result, arg->from, 4);
 163         return 0;
 164 }
 165
 166 /*
 167  * parse_options()
 168  *
 169  * adapted from linux/fs/msdos/inode.c written 1992,93 by Werner Almesberger
 170  * This function is called by hfs_read_super() to parse the mount options.
 171  */
 172 static int parse_options(char *options, struct hfs_sb_info *hsb)
 173 {
 174         char *p;
 175         substring_t args[MAX_OPT_ARGS];
 176         int tmp, token;
 177
 178         /* initialize the sb with defaults */
 179         hsb->s_uid = current->uid;
 180         hsb->s_gid = current->gid;
 181         hsb->s_file_umask = 0133;
 182         hsb->s_dir_umask = 0022;
 183         hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f); /* == '????' */
 184         hsb->s_quiet = 0;
 185         hsb->part = -1;
 186         hsb->session = -1;
 187
 188         if (!options)
 189                 return 1;
 190
 191         while ((p = strsep(&options, ",")) != NULL) {
 192                 if (!*p)
 193                         continue;
 194
 195                 token = match_token(p, tokens, args);
 196                 switch (token) {
 197                 case opt_uid:
 198                         if (match_int(&args[0], &tmp)) {
 199                                 printk("HFS: uid requires an argument\n");
 200                                 return 0;
 201                         }
 202                         hsb->s_uid = (uid_t)tmp;
 203                         break;
 204                 case opt_gid:
 205                         if (match_int(&args[0], &tmp)) {
 206                                 printk("HFS: gid requires an argument\n");
 207                                 return 0;
 208                         }
 209                         hsb->s_gid = (gid_t)tmp;
 210                         break;
 211                 case opt_umask:
 212                         if (match_octal(&args[0], &tmp)) {
 213                                 printk("HFS: umask requires a value\n");
 214                                 return 0;
 215                         }
 216                         hsb->s_file_umask = (umode_t)tmp;
 217                         hsb->s_dir_umask = (umode_t)tmp;
 218                         break;
 219                 case opt_file_umask:
 220                         if (match_octal(&args[0], &tmp)) {
 221                                 printk("HFS: file_umask requires a value\n");
 222                                 return 0;
 223                         }
 224                         hsb->s_file_umask = (umode_t)tmp;
 225                         break;
 226                 case opt_dir_umask:
 227                         if (match_octal(&args[0], &tmp)) {
 228                                 printk("HFS: dir_umask requires a value\n");
 229                                 return 0;
 230                         }
 231                         hsb->s_dir_umask = (umode_t)tmp;
 232                         break;
 233                 case opt_part:
 234                         if (match_int(&args[0], &hsb->part)) {
 235                                 printk("HFS: part requires an argument\n");
 236                                 return 0;
 237                         }
 238                         break;
 239                 case opt_session:
 240                         if (match_int(&args[0], &hsb->session)) {
 241                                 printk("HFS: session requires an argument\n");
 242                                 return 0;
 243                         }
 244                         break;
 245                 case opt_type:
 246                         if (match_fourchar(&args[0], &hsb->s_type)) {
 247                                 printk("HFS+-fs: type requires a 4 character value\n");
 248                                 return 0;
 249                         }
 250                         break;
 251                 case opt_creator:
 252                         if (match_fourchar(&args[0], &hsb->s_creator)) {
 253                                 printk("HFS+-fs: creator requires a 4 character value\n");
 254                                 return 0;
 255                         }
 256                         break;
 257                 case opt_quiet:
 258                         hsb->s_quiet = 1;
 259                         break;
 260                 default:
 261                         return 0;
 262                 }
 263         }
 264
 265         hsb->s_dir_umask &= 0777;
 266         hsb->s_file_umask &= 0577;
 267
 268         return 1;
 269 }
 270
 271 /*
 272  * hfs_read_super()
 273  *
 274  * This is the function that is responsible for mounting an HFS
 275  * filesystem.  It performs all the tasks necessary to get enough data
 276  * from the disk to read the root inode.  This includes parsing the
 277  * mount options, dealing with Macintosh partitions, reading the
 278  * superblock and the allocation bitmap blocks, calling
 279  * hfs_btree_init() to get the necessary data about the extents and
 280  * catalog B-trees and, finally, reading the root inode into memory.
 281  */
 282 static int hfs_fill_super(struct super_block *sb, void *data, int silent)
 283 {
 284         struct hfs_sb_info *sbi;
 285         struct hfs_find_data fd;
 286         hfs_cat_rec rec;
 287         struct inode *root_inode;
 288         int res;
 289
 290         sbi = kmalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
 291         if (!sbi)
 292                 return -ENOMEM;
 293         sb->s_fs_info = sbi;
 294         memset(sbi, 0, sizeof(struct hfs_sb_info));
 295         INIT_HLIST_HEAD(&sbi->rsrc_inodes);
 296
 297         res = -EINVAL;
 298         if (!parse_options((char *)data, sbi)) {
 299                 hfs_warn("hfs_fs: unable to parse mount options.\n");
 300                 goto bail;
 301         }
 302
 303         sb->s_op = &hfs_super_operations;
 304         sb->s_flags |= MS_NODIRATIME;
 305         init_MUTEX(&sbi->bitmap_lock);
 306
 307         res = hfs_mdb_get(sb);
 308         if (res) {
 309                 if (!silent)
 310                         hfs_warn("VFS: Can't find a HFS filesystem on dev %s.\n",
 311                                 hfs_mdb_name(sb));
 312                 res = -EINVAL;
 313                 goto bail;
 314         }
 315
 316         /* try to get the root inode */
 317         hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
 318         res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
 319         if (!res)
 320                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
 321         if (res) {
 322                 hfs_find_exit(&fd);
 323                 goto bail_no_root;
 324         }
 325         root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
 326         hfs_find_exit(&fd);
 327         if (!root_inode)
 328                 goto bail_no_root;
 329
 330         sb->s_root = d_alloc_root(root_inode);
 331         if (!sb->s_root)
 332                 goto bail_iput;
 333
 334         sb->s_root->d_op = &hfs_dentry_operations;
 335
 336         /* everything's okay */
 337         return 0;
 338
 339 bail_iput:
 340         iput(root_inode);
 341 bail_no_root:
 342         hfs_warn("hfs_fs: get root inode failed.\n");
 343 bail:
 344         hfs_mdb_put(sb);
 345         return res;
 346 }
 347
 348 static struct super_block *hfs_get_sb(struct file_system_type *fs_type,
 349                                       int flags, const char *dev_name, void *data)
 350 {
 351         return get_sb_bdev(fs_type, flags, dev_name, data, hfs_fill_super);
 352 }
 353
 354 static struct file_system_type hfs_fs_type = {
 355         .owner          = THIS_MODULE,
 356         .name           = "hfs",
 357         .get_sb         = hfs_get_sb,
 358         .kill_sb        = kill_block_super,
 359         .fs_flags       = FS_REQUIRES_DEV,
 360 };
 361
 362 static void hfs_init_once(void *p, kmem_cache_t *cachep, unsigned long flags)
 363 {
 364         struct hfs_inode_info *i = p;
 365
 366         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR)
 367                 inode_init_once(&i->vfs_inode);
 368 }
 369
 370 static int __init init_hfs_fs(void)
 371 {
 372         int err;
 373
 374         hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
 375                 sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
 376                 hfs_init_once, NULL);
 377         if (!hfs_inode_cachep)
 378                 return -ENOMEM;
 379         err = register_filesystem(&hfs_fs_type);
 380         if (err)
 381                 kmem_cache_destroy(hfs_inode_cachep);
 382         return err;
 383 }
 384
 385 static void __exit exit_hfs_fs(void)
 386 {
 387         unregister_filesystem(&hfs_fs_type);
 388         if (kmem_cache_destroy(hfs_inode_cachep))
 389                 printk(KERN_INFO "hfs_inode_cache: not all structures were freed\n");
 390 }
 391
 392 module_init(init_hfs_fs)
 393 module_exit(exit_hfs_fs)