fs/hfs/mdb.c

   1 /*
   2  *  linux/fs/hfs/mdb.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 functions for reading/writing the MDB.
   9  */
  10
  11 #include <linux/cdrom.h>
  12 #include <linux/genhd.h>
  13 #include <linux/nls.h>
  14
  15 #include "hfs_fs.h"
  16 #include "btree.h"
  17
  18 /*================ File-local data types ================*/
  19
  20 /*
  21  * The HFS Master Directory Block (MDB).
  22  *
  23  * Also known as the Volume Information Block (VIB), this structure is
  24  * the HFS equivalent of a superblock.
  25  *
  26  * Reference: _Inside Macintosh: Files_ pages 2-59 through 2-62
  27  *
  28  * modified for HFS Extended
  29  */
  30
  31 static int hfs_get_last_session(struct super_block *sb,
  32                                 sector_t *start, sector_t *size)
  33 {
  34         struct cdrom_multisession ms_info;
  35         struct cdrom_tocentry te;
  36         int res;
  37
  38         /* default values */
  39         *start = 0;
  40         *size = sb->s_bdev->bd_inode->i_size >> 9;
  41
  42         if (HFS_SB(sb)->session >= 0) {
  43                 te.cdte_track = HFS_SB(sb)->session;
  44                 te.cdte_format = CDROM_LBA;
  45                 res = ioctl_by_bdev(sb->s_bdev, CDROMREADTOCENTRY, (unsigned long)&te);
  46                 if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
  47                         *start = (sector_t)te.cdte_addr.lba << 2;
  48                         return 0;
  49                 }
  50                 printk(KERN_ERR "hfs: invalid session number or type of track\n");
  51                 return -EINVAL;
  52         }
  53         ms_info.addr_format = CDROM_LBA;
  54         res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, (unsigned long)&ms_info);
  55         if (!res && ms_info.xa_flag)
  56                 *start = (sector_t)ms_info.addr.lba << 2;
  57         return 0;
  58 }
  59
  60 /*
  61  * hfs_mdb_get()
  62  *
  63  * Build the in-core MDB for a filesystem, including
  64  * the B-trees and the volume bitmap.
  65  */
  66 int hfs_mdb_get(struct super_block *sb)
  67 {
  68         struct buffer_head *bh;
  69         struct hfs_mdb *mdb, *mdb2;
  70         unsigned int block;
  71         char *ptr;
  72         int off2, len, size, sect;
  73         sector_t part_start, part_size;
  74         loff_t off;
  75         __be16 attrib;
  76
  77         /* set the device driver to 512-byte blocks */
  78         size = sb_min_blocksize(sb, HFS_SECTOR_SIZE);
  79         if (!size)
  80                 return -EINVAL;
  81
  82         if (hfs_get_last_session(sb, &part_start, &part_size))
  83                 return -EINVAL;
  84         while (1) {
  85                 /* See if this is an HFS filesystem */
  86                 bh = sb_bread512(sb, part_start + HFS_MDB_BLK, mdb);
  87                 if (!bh)
  88                         goto out;
  89
  90                 if (mdb->drSigWord == cpu_to_be16(HFS_SUPER_MAGIC))
  91                         break;
  92                 brelse(bh);
  93
  94                 /* check for a partition block
  95                  * (should do this only for cdrom/loop though)
  96                  */
  97                 if (hfs_part_find(sb, &part_start, &part_size))
  98                         goto out;
  99         }
 100
 101         HFS_SB(sb)->alloc_blksz = size = be32_to_cpu(mdb->drAlBlkSiz);
 102         if (!size || (size & (HFS_SECTOR_SIZE - 1))) {
 103                 printk(KERN_ERR "hfs: bad allocation block size %d\n", size);
 104                 goto out_bh;
 105         }
 106
 107         size = min(HFS_SB(sb)->alloc_blksz, (u32)PAGE_SIZE);
 108         /* size must be a multiple of 512 */
 109         while (size & (size - 1))
 110                 size -= HFS_SECTOR_SIZE;
 111         sect = be16_to_cpu(mdb->drAlBlSt) + part_start;
 112         /* align block size to first sector */
 113         while (sect & ((size - 1) >> HFS_SECTOR_SIZE_BITS))
 114                 size >>= 1;
 115         /* align block size to weird alloc size */
 116         while (HFS_SB(sb)->alloc_blksz & (size - 1))
 117                 size >>= 1;
 118         brelse(bh);
 119         if (!sb_set_blocksize(sb, size)) {
 120                 printk(KERN_ERR "hfs: unable to set blocksize to %u\n", size);
 121                 goto out;
 122         }
 123
 124         bh = sb_bread512(sb, part_start + HFS_MDB_BLK, mdb);
 125         if (!bh)
 126                 goto out;
 127         if (mdb->drSigWord != cpu_to_be16(HFS_SUPER_MAGIC))
 128                 goto out_bh;
 129
 130         HFS_SB(sb)->mdb_bh = bh;
 131         HFS_SB(sb)->mdb = mdb;
 132
 133         /* These parameters are read from the MDB, and never written */
 134         HFS_SB(sb)->part_start = part_start;
 135         HFS_SB(sb)->fs_ablocks = be16_to_cpu(mdb->drNmAlBlks);
 136         HFS_SB(sb)->fs_div = HFS_SB(sb)->alloc_blksz >> sb->s_blocksize_bits;
 137         HFS_SB(sb)->clumpablks = be32_to_cpu(mdb->drClpSiz) /
 138                                  HFS_SB(sb)->alloc_blksz;
 139         if (!HFS_SB(sb)->clumpablks)
 140                 HFS_SB(sb)->clumpablks = 1;
 141         HFS_SB(sb)->fs_start = (be16_to_cpu(mdb->drAlBlSt) + part_start) >>
 142                                (sb->s_blocksize_bits - HFS_SECTOR_SIZE_BITS);
 143
 144         /* These parameters are read from and written to the MDB */
 145         HFS_SB(sb)->free_ablocks = be16_to_cpu(mdb->drFreeBks);
 146         HFS_SB(sb)->next_id = be32_to_cpu(mdb->drNxtCNID);
 147         HFS_SB(sb)->root_files = be16_to_cpu(mdb->drNmFls);
 148         HFS_SB(sb)->root_dirs = be16_to_cpu(mdb->drNmRtDirs);
 149         HFS_SB(sb)->file_count = be32_to_cpu(mdb->drFilCnt);
 150         HFS_SB(sb)->folder_count = be32_to_cpu(mdb->drDirCnt);
 151
 152         /* TRY to get the alternate (backup) MDB. */
 153         sect = part_start + part_size - 2;
 154         bh = sb_bread512(sb, sect, mdb2);
 155         if (bh) {
 156                 if (mdb2->drSigWord == cpu_to_be16(HFS_SUPER_MAGIC)) {
 157                         HFS_SB(sb)->alt_mdb_bh = bh;
 158                         HFS_SB(sb)->alt_mdb = mdb2;
 159                 } else
 160                         brelse(bh);
 161         }
 162
 163         if (!HFS_SB(sb)->alt_mdb) {
 164                 printk(KERN_WARNING "hfs: unable to locate alternate MDB\n");
 165                 printk(KERN_WARNING "hfs: continuing without an alternate MDB\n");
 166         }
 167
 168         HFS_SB(sb)->bitmap = (__be32 *)__get_free_pages(GFP_KERNEL, PAGE_SIZE < 8192 ? 1 : 0);
 169         if (!HFS_SB(sb)->bitmap)
 170                 goto out;
 171
 172         /* read in the bitmap */
 173         block = be16_to_cpu(mdb->drVBMSt) + part_start;
 174         off = (loff_t)block << HFS_SECTOR_SIZE_BITS;
 175         size = (HFS_SB(sb)->fs_ablocks + 8) / 8;
 176         ptr = (u8 *)HFS_SB(sb)->bitmap;
 177         while (size) {
 178                 bh = sb_bread(sb, off >> sb->s_blocksize_bits);
 179                 if (!bh) {
 180                         printk(KERN_ERR "hfs: unable to read volume bitmap\n");
 181                         goto out;
 182                 }
 183                 off2 = off & (sb->s_blocksize - 1);
 184                 len = min((int)sb->s_blocksize - off2, size);
 185                 memcpy(ptr, bh->b_data + off2, len);
 186                 brelse(bh);
 187                 ptr += len;
 188                 off += len;
 189                 size -= len;
 190         }
 191
 192         HFS_SB(sb)->ext_tree = hfs_btree_open(sb, HFS_EXT_CNID, hfs_ext_keycmp);
 193         if (!HFS_SB(sb)->ext_tree) {
 194                 printk(KERN_ERR "hfs: unable to open extent tree\n");
 195                 goto out;
 196         }
 197         HFS_SB(sb)->cat_tree = hfs_btree_open(sb, HFS_CAT_CNID, hfs_cat_keycmp);
 198         if (!HFS_SB(sb)->cat_tree) {
 199                 printk(KERN_ERR "hfs: unable to open catalog tree\n");
 200                 goto out;
 201         }
 202
 203         attrib = mdb->drAtrb;
 204         if (!(attrib & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
 205                 printk(KERN_WARNING "hfs: filesystem was not cleanly unmounted, "
 206                          "running fsck.hfs is recommended.  mounting read-only.\n");
 207                 sb->s_flags |= MS_RDONLY;
 208         }
 209         if ((attrib & cpu_to_be16(HFS_SB_ATTRIB_SLOCK))) {
 210                 printk(KERN_WARNING "hfs: filesystem is marked locked, mounting read-only.\n");
 211                 sb->s_flags |= MS_RDONLY;
 212         }
 213         if (!(sb->s_flags & MS_RDONLY)) {
 214                 /* Mark the volume uncleanly unmounted in case we crash */
 215                 attrib &= cpu_to_be16(~HFS_SB_ATTRIB_UNMNT);
 216                 attrib |= cpu_to_be16(HFS_SB_ATTRIB_INCNSTNT);
 217                 mdb->drAtrb = attrib;
 218                 mdb->drWrCnt = cpu_to_be32(be32_to_cpu(mdb->drWrCnt) + 1);
 219                 mdb->drLsMod = hfs_mtime();
 220
 221                 mark_buffer_dirty(HFS_SB(sb)->mdb_bh);
 222                 hfs_buffer_sync(HFS_SB(sb)->mdb_bh);
 223         }
 224
 225         return 0;
 226
 227 out_bh:
 228         brelse(bh);
 229 out:
 230         hfs_mdb_put(sb);
 231         return -EIO;
 232 }
 233
 234 /*
 235  * hfs_mdb_commit()
 236  *
 237  * Description:
 238  *   This updates the MDB on disk (look also at hfs_write_super()).
 239  *   It does not check, if the superblock has been modified, or
 240  *   if the filesystem has been mounted read-only. It is mainly
 241  *   called by hfs_write_super() and hfs_btree_extend().
 242  * Input Variable(s):
 243  *   struct hfs_mdb *mdb: Pointer to the hfs MDB
 244  *   int backup;
 245  * Output Variable(s):
 246  *   NONE
 247  * Returns:
 248  *   void
 249  * Preconditions:
 250  *   'mdb' points to a "valid" (struct hfs_mdb).
 251  * Postconditions:
 252  *   The HFS MDB and on disk will be updated, by copying the possibly
 253  *   modified fields from the in memory MDB (in native byte order) to
 254  *   the disk block buffer.
 255  *   If 'backup' is non-zero then the alternate MDB is also written
 256  *   and the function doesn't return until it is actually on disk.
 257  */
 258 void hfs_mdb_commit(struct super_block *sb)
 259 {
 260         struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
 261
 262         if (test_and_clear_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags)) {
 263                 /* These parameters may have been modified, so write them back */
 264                 mdb->drLsMod = hfs_mtime();
 265                 mdb->drFreeBks = cpu_to_be16(HFS_SB(sb)->free_ablocks);
 266                 mdb->drNxtCNID = cpu_to_be32(HFS_SB(sb)->next_id);
 267                 mdb->drNmFls = cpu_to_be16(HFS_SB(sb)->root_files);
 268                 mdb->drNmRtDirs = cpu_to_be16(HFS_SB(sb)->root_dirs);
 269                 mdb->drFilCnt = cpu_to_be32(HFS_SB(sb)->file_count);
 270                 mdb->drDirCnt = cpu_to_be32(HFS_SB(sb)->folder_count);
 271
 272                 /* write MDB to disk */
 273                 mark_buffer_dirty(HFS_SB(sb)->mdb_bh);
 274         }
 275
 276         /* write the backup MDB, not returning until it is written.
 277          * we only do this when either the catalog or extents overflow
 278          * files grow. */
 279         if (test_and_clear_bit(HFS_FLG_ALT_MDB_DIRTY, &HFS_SB(sb)->flags) &&
 280             HFS_SB(sb)->alt_mdb) {
 281                 hfs_inode_write_fork(HFS_SB(sb)->ext_tree->inode, mdb->drXTExtRec,
 282                                      &mdb->drXTFlSize, NULL);
 283                 hfs_inode_write_fork(HFS_SB(sb)->cat_tree->inode, mdb->drCTExtRec,
 284                                      &mdb->drCTFlSize, NULL);
 285                 memcpy(HFS_SB(sb)->alt_mdb, HFS_SB(sb)->mdb, HFS_SECTOR_SIZE);
 286                 HFS_SB(sb)->alt_mdb->drAtrb |= cpu_to_be16(HFS_SB_ATTRIB_UNMNT);
 287                 HFS_SB(sb)->alt_mdb->drAtrb &= cpu_to_be16(~HFS_SB_ATTRIB_INCNSTNT);
 288                 mark_buffer_dirty(HFS_SB(sb)->alt_mdb_bh);
 289                 hfs_buffer_sync(HFS_SB(sb)->alt_mdb_bh);
 290         }
 291
 292         if (test_and_clear_bit(HFS_FLG_BITMAP_DIRTY, &HFS_SB(sb)->flags)) {
 293                 struct buffer_head *bh;
 294                 sector_t block;
 295                 char *ptr;
 296                 int off, size, len;
 297
 298                 block = be16_to_cpu(HFS_SB(sb)->mdb->drVBMSt) + HFS_SB(sb)->part_start;
 299                 off = (block << HFS_SECTOR_SIZE_BITS) & (sb->s_blocksize - 1);
 300                 block >>= sb->s_blocksize_bits - HFS_SECTOR_SIZE_BITS;
 301                 size = (HFS_SB(sb)->fs_ablocks + 7) / 8;
 302                 ptr = (u8 *)HFS_SB(sb)->bitmap;
 303                 while (size) {
 304                         bh = sb_bread(sb, block);
 305                         if (!bh) {
 306                                 printk(KERN_ERR "hfs: unable to read volume bitmap\n");
 307                                 break;
 308                         }
 309                         len = min((int)sb->s_blocksize - off, size);
 310                         memcpy(bh->b_data + off, ptr, len);
 311                         mark_buffer_dirty(bh);
 312                         brelse(bh);
 313                         block++;
 314                         off = 0;
 315                         ptr += len;
 316                         size -= len;
 317                 }
 318         }
 319 }
 320
 321 void hfs_mdb_close(struct super_block *sb)
 322 {
 323         /* update volume attributes */
 324         if (sb->s_flags & MS_RDONLY)
 325                 return;
 326         HFS_SB(sb)->mdb->drAtrb |= cpu_to_be16(HFS_SB_ATTRIB_UNMNT);
 327         HFS_SB(sb)->mdb->drAtrb &= cpu_to_be16(~HFS_SB_ATTRIB_INCNSTNT);
 328         mark_buffer_dirty(HFS_SB(sb)->mdb_bh);
 329 }
 330
 331 /*
 332  * hfs_mdb_put()
 333  *
 334  * Release the resources associated with the in-core MDB.  */
 335 void hfs_mdb_put(struct super_block *sb)
 336 {
 337         if (!HFS_SB(sb))
 338                 return;
 339         /* free the B-trees */
 340         hfs_btree_close(HFS_SB(sb)->ext_tree);
 341         hfs_btree_close(HFS_SB(sb)->cat_tree);
 342
 343         /* free the buffers holding the primary and alternate MDBs */
 344         brelse(HFS_SB(sb)->mdb_bh);
 345         brelse(HFS_SB(sb)->alt_mdb_bh);
 346
 347         if (HFS_SB(sb)->nls_io)
 348                 unload_nls(HFS_SB(sb)->nls_io);
 349         if (HFS_SB(sb)->nls_disk)
 350                 unload_nls(HFS_SB(sb)->nls_disk);
 351
 352         kfree(HFS_SB(sb));
 353         sb->s_fs_info = NULL;
 354 }