1 files changed, 343 insertions, 0 deletions

diff --git a/fs/hfs/mdb.c b/fs/hfs/mdb.c
new file mode 100644
index 000000000000..4efb640c4d0c
--- /dev/null
+++ b/fs/hfs/mdb.c
@@ -0,0 +1,343 @@
+/*
+ *  linux/fs/hfs/mdb.c
+ *
+ * Copyright (C) 1995-1997  Paul H. Hargrove
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ * This file may be distributed under the terms of the GNU General Public License.
+ *
+ * This file contains functions for reading/writing the MDB.
+ */
+
+#include <linux/cdrom.h>
+#include <linux/genhd.h>
+
+#include "hfs_fs.h"
+#include "btree.h"
+
+/*================ File-local data types ================*/
+
+/*
+ * The HFS Master Directory Block (MDB).
+ *
+ * Also known as the Volume Information Block (VIB), this structure is
+ * the HFS equivalent of a superblock.
+ *
+ * Reference: _Inside Macintosh: Files_ pages 2-59 through 2-62
+ *
+ * modified for HFS Extended
+ */
+
+static int hfs_get_last_session(struct super_block *sb,
+                                sector_t *start, sector_t *size)
+{
+        struct cdrom_multisession ms_info;
+        struct cdrom_tocentry te;
+        int res;
+
+        /* default values */
+        *start = 0;
+        *size = sb->s_bdev->bd_inode->i_size >> 9;
+
+        if (HFS_SB(sb)->session >= 0) {
+                te.cdte_track = HFS_SB(sb)->session;
+                te.cdte_format = CDROM_LBA;
+                res = ioctl_by_bdev(sb->s_bdev, CDROMREADTOCENTRY, (unsigned long)&te);
+                if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
+                        *start = (sector_t)te.cdte_addr.lba << 2;
+                        return 0;
+                }
+                printk(KERN_ERR "HFS: Invalid session number or type of track\n");
+                return -EINVAL;
+        }
+        ms_info.addr_format = CDROM_LBA;
+        res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, (unsigned long)&ms_info);
+        if (!res && ms_info.xa_flag)
+                *start = (sector_t)ms_info.addr.lba << 2;
+        return 0;
+}
+
+/*
+ * hfs_mdb_get()
+ *
+ * Build the in-core MDB for a filesystem, including
+ * the B-trees and the volume bitmap.
+ */
+int hfs_mdb_get(struct super_block *sb)
+{
+        struct buffer_head *bh;
+        struct hfs_mdb *mdb, *mdb2;
+        unsigned int block;
+        char *ptr;
+        int off2, len, size, sect;
+        sector_t part_start, part_size;
+        loff_t off;
+        __be16 attrib;
+
+        /* set the device driver to 512-byte blocks */
+        size = sb_min_blocksize(sb, HFS_SECTOR_SIZE);
+        if (!size)
+                return -EINVAL;
+
+        if (hfs_get_last_session(sb, &part_start, &part_size))
+                return -EINVAL;
+        while (1) {
+                /* See if this is an HFS filesystem */
+                bh = sb_bread512(sb, part_start + HFS_MDB_BLK, mdb);
+                if (!bh)
+                        goto out;
+
+                if (mdb->drSigWord == cpu_to_be16(HFS_SUPER_MAGIC))
+                        break;
+                brelse(bh);
+
+                /* check for a partition block
+                 * (should do this only for cdrom/loop though)
+                 */
+                if (hfs_part_find(sb, &part_start, &part_size))
+                        goto out;
+        }
+
+        HFS_SB(sb)->alloc_blksz = size = be32_to_cpu(mdb->drAlBlkSiz);
+        if (!size || (size & (HFS_SECTOR_SIZE - 1))) {
+                hfs_warn("hfs_fs: bad allocation block size %d\n", size);
+                goto out_bh;
+        }
+
+        size = min(HFS_SB(sb)->alloc_blksz, (u32)PAGE_SIZE);
+        /* size must be a multiple of 512 */
+        while (size & (size - 1))
+                size -= HFS_SECTOR_SIZE;
+        sect = be16_to_cpu(mdb->drAlBlSt) + part_start;
+        /* align block size to first sector */
+        while (sect & ((size - 1) >> HFS_SECTOR_SIZE_BITS))
+                size >>= 1;
+        /* align block size to weird alloc size */
+        while (HFS_SB(sb)->alloc_blksz & (size - 1))
+                size >>= 1;
+        brelse(bh);
+        if (!sb_set_blocksize(sb, size)) {
+                printk("hfs_fs: unable to set blocksize to %u\n", size);
+                goto out;
+        }
+
+        bh = sb_bread512(sb, part_start + HFS_MDB_BLK, mdb);
+        if (!bh)
+                goto out;
+        if (mdb->drSigWord != cpu_to_be16(HFS_SUPER_MAGIC))
+                goto out_bh;
+
+        HFS_SB(sb)->mdb_bh = bh;
+        HFS_SB(sb)->mdb = mdb;
+
+        /* These parameters are read from the MDB, and never written */
+        HFS_SB(sb)->part_start = part_start;
+        HFS_SB(sb)->fs_ablocks = be16_to_cpu(mdb->drNmAlBlks);
+        HFS_SB(sb)->fs_div = HFS_SB(sb)->alloc_blksz >> sb->s_blocksize_bits;
+        HFS_SB(sb)->clumpablks = be32_to_cpu(mdb->drClpSiz) /
+                                 HFS_SB(sb)->alloc_blksz;
+        if (!HFS_SB(sb)->clumpablks)
+                HFS_SB(sb)->clumpablks = 1;
+        HFS_SB(sb)->fs_start = (be16_to_cpu(mdb->drAlBlSt) + part_start) >>
+                               (sb->s_blocksize_bits - HFS_SECTOR_SIZE_BITS);
+
+        /* These parameters are read from and written to the MDB */
+        HFS_SB(sb)->free_ablocks = be16_to_cpu(mdb->drFreeBks);
+        HFS_SB(sb)->next_id = be32_to_cpu(mdb->drNxtCNID);
+        HFS_SB(sb)->root_files = be16_to_cpu(mdb->drNmFls);
+        HFS_SB(sb)->root_dirs = be16_to_cpu(mdb->drNmRtDirs);
+        HFS_SB(sb)->file_count = be32_to_cpu(mdb->drFilCnt);
+        HFS_SB(sb)->folder_count = be32_to_cpu(mdb->drDirCnt);
+
+        /* TRY to get the alternate (backup) MDB. */
+        sect = part_start + part_size - 2;
+        bh = sb_bread512(sb, sect, mdb2);
+        if (bh) {
+                if (mdb2->drSigWord == cpu_to_be16(HFS_SUPER_MAGIC)) {
+                        HFS_SB(sb)->alt_mdb_bh = bh;
+                        HFS_SB(sb)->alt_mdb = mdb2;
+                } else
+                        brelse(bh);
+        }
+
+        if (!HFS_SB(sb)->alt_mdb) {
+                hfs_warn("hfs_fs: unable to locate alternate MDB\n");
+                hfs_warn("hfs_fs: continuing without an alternate MDB\n");
+        }
+
+        HFS_SB(sb)->bitmap = (__be32 *)__get_free_pages(GFP_KERNEL, PAGE_SIZE < 8192 ? 1 : 0);
+        if (!HFS_SB(sb)->bitmap)
+                goto out;
+
+        /* read in the bitmap */
+        block = be16_to_cpu(mdb->drVBMSt) + part_start;
+        off = (loff_t)block << HFS_SECTOR_SIZE_BITS;
+        size = (HFS_SB(sb)->fs_ablocks + 8) / 8;
+        ptr = (u8 *)HFS_SB(sb)->bitmap;
+        while (size) {
+                bh = sb_bread(sb, off >> sb->s_blocksize_bits);
+                if (!bh) {
+                        hfs_warn("hfs_fs: unable to read volume bitmap\n");
+                        goto out;
+                }
+                off2 = off & (sb->s_blocksize - 1);
+                len = min((int)sb->s_blocksize - off2, size);
+                memcpy(ptr, bh->b_data + off2, len);
+                brelse(bh);
+                ptr += len;
+                off += len;
+                size -= len;
+        }
+
+        HFS_SB(sb)->ext_tree = hfs_btree_open(sb, HFS_EXT_CNID, hfs_ext_keycmp);
+        if (!HFS_SB(sb)->ext_tree) {
+                hfs_warn("hfs_fs: unable to open extent tree\n");
+                goto out;
+        }
+        HFS_SB(sb)->cat_tree = hfs_btree_open(sb, HFS_CAT_CNID, hfs_cat_keycmp);
+        if (!HFS_SB(sb)->cat_tree) {
+                hfs_warn("hfs_fs: unable to open catalog tree\n");
+                goto out;
+        }
+
+        attrib = mdb->drAtrb;
+        if (!(attrib & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
+                hfs_warn("HFS-fs warning: Filesystem was not cleanly unmounted, "
+                         "running fsck.hfs is recommended.  mounting read-only.\n");
+                sb->s_flags |= MS_RDONLY;
+        }
+        if ((attrib & cpu_to_be16(HFS_SB_ATTRIB_SLOCK))) {
+                hfs_warn("HFS-fs: Filesystem is marked locked, mounting read-only.\n");
+                sb->s_flags |= MS_RDONLY;
+        }
+        if (!(sb->s_flags & MS_RDONLY)) {
+                /* Mark the volume uncleanly unmounted in case we crash */
+                attrib &= cpu_to_be16(~HFS_SB_ATTRIB_UNMNT);
+                attrib |= cpu_to_be16(HFS_SB_ATTRIB_INCNSTNT);
+                mdb->drAtrb = attrib;
+                mdb->drWrCnt = cpu_to_be32(be32_to_cpu(mdb->drWrCnt) + 1);
+                mdb->drLsMod = hfs_mtime();
+
+                mark_buffer_dirty(HFS_SB(sb)->mdb_bh);
+                hfs_buffer_sync(HFS_SB(sb)->mdb_bh);
+        }
+
+        return 0;
+
+out_bh:
+        brelse(bh);
+out:
+        hfs_mdb_put(sb);
+        return -EIO;
+}
+
+/*
+ * hfs_mdb_commit()
+ *
+ * Description:
+ *   This updates the MDB on disk (look also at hfs_write_super()).
+ *   It does not check, if the superblock has been modified, or
+ *   if the filesystem has been mounted read-only. It is mainly
+ *   called by hfs_write_super() and hfs_btree_extend().
+ * Input Variable(s):
+ *   struct hfs_mdb *mdb: Pointer to the hfs MDB
+ *   int backup;
+ * Output Variable(s):
+ *   NONE
+ * Returns:
+ *   void
+ * Preconditions:
+ *   'mdb' points to a "valid" (struct hfs_mdb).
+ * Postconditions:
+ *   The HFS MDB and on disk will be updated, by copying the possibly
+ *   modified fields from the in memory MDB (in native byte order) to
+ *   the disk block buffer.
+ *   If 'backup' is non-zero then the alternate MDB is also written
+ *   and the function doesn't return until it is actually on disk.
+ */
+void hfs_mdb_commit(struct super_block *sb)
+{
+        struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
+
+        if (test_and_clear_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags)) {
+                /* These parameters may have been modified, so write them back */
+                mdb->drLsMod = hfs_mtime();
+                mdb->drFreeBks = cpu_to_be16(HFS_SB(sb)->free_ablocks);
+                mdb->drNxtCNID = cpu_to_be32(HFS_SB(sb)->next_id);
+                mdb->drNmFls = cpu_to_be16(HFS_SB(sb)->root_files);
+                mdb->drNmRtDirs = cpu_to_be16(HFS_SB(sb)->root_dirs);
+                mdb->drFilCnt = cpu_to_be32(HFS_SB(sb)->file_count);
+                mdb->drDirCnt = cpu_to_be32(HFS_SB(sb)->folder_count);
+
+                /* write MDB to disk */
+                mark_buffer_dirty(HFS_SB(sb)->mdb_bh);
+        }
+
+        /* write the backup MDB, not returning until it is written.
+         * we only do this when either the catalog or extents overflow
+         * files grow. */
+        if (test_and_clear_bit(HFS_FLG_ALT_MDB_DIRTY, &HFS_SB(sb)->flags) &&
+            HFS_SB(sb)->alt_mdb) {
+                hfs_inode_write_fork(HFS_SB(sb)->ext_tree->inode, mdb->drXTExtRec,
+                                     &mdb->drXTFlSize, NULL);
+                hfs_inode_write_fork(HFS_SB(sb)->cat_tree->inode, mdb->drCTExtRec,
+                                     &mdb->drCTFlSize, NULL);
+                memcpy(HFS_SB(sb)->alt_mdb, HFS_SB(sb)->mdb, HFS_SECTOR_SIZE);
+                HFS_SB(sb)->alt_mdb->drAtrb |= cpu_to_be16(HFS_SB_ATTRIB_UNMNT);
+                HFS_SB(sb)->alt_mdb->drAtrb &= cpu_to_be16(~HFS_SB_ATTRIB_INCNSTNT);
+                mark_buffer_dirty(HFS_SB(sb)->alt_mdb_bh);
+                hfs_buffer_sync(HFS_SB(sb)->alt_mdb_bh);
+        }
+
+        if (test_and_clear_bit(HFS_FLG_BITMAP_DIRTY, &HFS_SB(sb)->flags)) {
+                struct buffer_head *bh;
+                sector_t block;
+                char *ptr;
+                int off, size, len;
+
+                block = be16_to_cpu(HFS_SB(sb)->mdb->drVBMSt) + HFS_SB(sb)->part_start;
+                off = (block << HFS_SECTOR_SIZE_BITS) & (sb->s_blocksize - 1);
+                block >>= sb->s_blocksize_bits - HFS_SECTOR_SIZE_BITS;
+                size = (HFS_SB(sb)->fs_ablocks + 7) / 8;
+                ptr = (u8 *)HFS_SB(sb)->bitmap;
+                while (size) {
+                        bh = sb_bread(sb, block);
+                        if (!bh) {
+                                hfs_warn("hfs_fs: unable to read volume bitmap\n");
+                                break;
+                        }
+                        len = min((int)sb->s_blocksize - off, size);
+                        memcpy(bh->b_data + off, ptr, len);
+                        mark_buffer_dirty(bh);
+                        brelse(bh);
+                        block++;
+                        off = 0;
+                        ptr += len;
+                        size -= len;
+                }
+        }
+}
+
+void hfs_mdb_close(struct super_block *sb)
+{
+        /* update volume attributes */
+        if (sb->s_flags & MS_RDONLY)
+                return;
+        HFS_SB(sb)->mdb->drAtrb |= cpu_to_be16(HFS_SB_ATTRIB_UNMNT);
+        HFS_SB(sb)->mdb->drAtrb &= cpu_to_be16(~HFS_SB_ATTRIB_INCNSTNT);
+        mark_buffer_dirty(HFS_SB(sb)->mdb_bh);
+}
+
+/*
+ * hfs_mdb_put()
+ *
+ * Release the resources associated with the in-core MDB.  */
+void hfs_mdb_put(struct super_block *sb)
+{
+        /* free the B-trees */
+        hfs_btree_close(HFS_SB(sb)->ext_tree);
+        hfs_btree_close(HFS_SB(sb)->cat_tree);
+
+        /* free the buffers holding the primary and alternate MDBs */
+        brelse(HFS_SB(sb)->mdb_bh);
+        brelse(HFS_SB(sb)->alt_mdb_bh);
+}