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/*
* 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 <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;
__be16 sig;
sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG);
if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
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 = 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;
if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) {
HFSPLUS_SB(sb).flags |= HFSPLUS_SB_HFSX;
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(KERN_ERR "hfs: unable to set 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 (vhdr->signature != (HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX ?
cpu_to_be16(HFSPLUS_VOLHEAD_SIGX) :
cpu_to_be16(HFSPLUS_VOLHEAD_SIG)))
goto error;
HFSPLUS_SB(sb).s_vhbh = bh;
HFSPLUS_SB(sb).s_vhdr = vhdr;
return 0;
error:
brelse(bh);
return -EINVAL;
}
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