1 files changed, 171 insertions, 0 deletions

diff --git a/fs/hfsplus/wrapper.c b/fs/hfsplus/wrapper.c
new file mode 100644
index 000000000000..0c51d6338b0b
--- /dev/null
+++ b/fs/hfsplus/wrapper.c
@@ -0,0 +1,171 @@
+/*
+ *  linux/fs/hfsplus/wrapper.c
+ *
+ * Copyright (C) 2001
+ * Brad Boyer (flar@allandria.com)
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ *
+ * Handling of HFS wrappers around HFS+ volumes
+ */
+
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/cdrom.h>
+#include <linux/genhd.h>
+#include <linux/version.h>
+#include <asm/unaligned.h>
+
+#include "hfsplus_fs.h"
+#include "hfsplus_raw.h"
+
+struct hfsplus_wd {
+        u32 ablk_size;
+        u16 ablk_start;
+        u16 embed_start;
+        u16 embed_count;
+};
+
+static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd)
+{
+        u32 extent;
+        u16 attrib;
+
+        if (be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG)) != HFSPLUS_VOLHEAD_SIG)
+                return 0;
+
+        attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB));
+        if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) ||
+           !(attrib & HFSP_WRAP_ATTRIB_SPARED))
+                return 0;
+
+        wd->ablk_size = be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE));
+        if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
+                return 0;
+        if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
+                return 0;
+        wd->ablk_start = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART));
+
+        extent = be32_to_cpu(get_unaligned((__be32 *)(bufptr + HFSP_WRAPOFF_EMBEDEXT)));
+        wd->embed_start = (extent >> 16) & 0xFFFF;
+        wd->embed_count = extent & 0xFFFF;
+
+        return 1;
+}
+
+static int hfsplus_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 (HFSPLUS_SB(sb).session >= 0) {
+                te.cdte_track = HFSPLUS_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;
+}
+
+/* Find the volume header and fill in some minimum bits in superblock */
+/* Takes in super block, returns true if good data read */
+int hfsplus_read_wrapper(struct super_block *sb)
+{
+        struct buffer_head *bh;
+        struct hfsplus_vh *vhdr;
+        struct hfsplus_wd wd;
+        sector_t part_start, part_size;
+        u32 blocksize;
+
+        blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
+        if (!blocksize)
+                return -EINVAL;
+
+        if (hfsplus_get_last_session(sb, &part_start, &part_size))
+                return -EINVAL;
+        while (1) {
+                bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
+                if (!bh)
+                        return -EIO;
+
+                if (vhdr->signature == cpu_to_be16(HFSP_WRAP_MAGIC)) {
+                        if (!hfsplus_read_mdb(vhdr, &wd))
+                                goto error;
+                        wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
+                        part_start += wd.ablk_start + wd.embed_start * wd.ablk_size;
+                        part_size = wd.embed_count * wd.ablk_size;
+                        brelse(bh);
+                        bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
+                        if (!bh)
+                                return -EIO;
+                }
+                if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIG))
+                        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))
+                        return -EINVAL;
+        }
+
+        blocksize = be32_to_cpu(vhdr->blocksize);
+        brelse(bh);
+
+        /* block size must be at least as large as a sector
+         * and a multiple of 2
+         */
+        if (blocksize < HFSPLUS_SECTOR_SIZE ||
+            ((blocksize - 1) & blocksize))
+                return -EINVAL;
+        HFSPLUS_SB(sb).alloc_blksz = blocksize;
+        HFSPLUS_SB(sb).alloc_blksz_shift = 0;
+        while ((blocksize >>= 1) != 0)
+                HFSPLUS_SB(sb).alloc_blksz_shift++;
+        blocksize = min(HFSPLUS_SB(sb).alloc_blksz, (u32)PAGE_SIZE);
+
+        /* align block size to block offset */
+        while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
+                blocksize >>= 1;
+
+        if (sb_set_blocksize(sb, blocksize) != blocksize) {
+                printk("HFS+: unable to blocksize to %u!\n", blocksize);
+                return -EINVAL;
+        }
+
+        HFSPLUS_SB(sb).blockoffset = part_start >>
+                        (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
+        HFSPLUS_SB(sb).sect_count = part_size;
+        HFSPLUS_SB(sb).fs_shift = HFSPLUS_SB(sb).alloc_blksz_shift -
+                        sb->s_blocksize_bits;
+
+        bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
+        if (!bh)
+                return -EIO;
+
+        /* should still be the same... */
+        if (be16_to_cpu(vhdr->signature) != HFSPLUS_VOLHEAD_SIG)
+                goto error;
+        HFSPLUS_SB(sb).s_vhbh = bh;
+        HFSPLUS_SB(sb).s_vhdr = vhdr;
+
+        return 0;
+ error:
+        brelse(bh);
+        return -EINVAL;
+}