/* * 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 = 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; 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; }