1 /* 2 * linux/fs/hfsplus/wrapper.c 3 * 4 * Copyright (C) 2001 5 * Brad Boyer (flar@allandria.com) 6 * (C) 2003 Ardis Technologies <roman@ardistech.com> 7 * 8 * Handling of HFS wrappers around HFS+ volumes 9 */ 10 11 #include <linux/fs.h> 12 #include <linux/blkdev.h> 13 #include <linux/cdrom.h> 14 #include <linux/genhd.h> 15 #include <asm/unaligned.h> 16 17 #include "hfsplus_fs.h" 18 #include "hfsplus_raw.h" 19 20 struct hfsplus_wd { 21 u32 ablk_size; 22 u16 ablk_start; 23 u16 embed_start; 24 u16 embed_count; 25 }; 26 27 static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd) 28 { 29 u32 extent; 30 u16 attrib; 31 __be16 sig; 32 33 sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG); 34 if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) && 35 sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) 36 return 0; 37 38 attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB)); 39 if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) || 40 !(attrib & HFSP_WRAP_ATTRIB_SPARED)) 41 return 0; 42 43 wd->ablk_size = be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE)); 44 if (wd->ablk_size < HFSPLUS_SECTOR_SIZE) 45 return 0; 46 if (wd->ablk_size % HFSPLUS_SECTOR_SIZE) 47 return 0; 48 wd->ablk_start = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART)); 49 50 extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT); 51 wd->embed_start = (extent >> 16) & 0xFFFF; 52 wd->embed_count = extent & 0xFFFF; 53 54 return 1; 55 } 56 57 static int hfsplus_get_last_session(struct super_block *sb, 58 sector_t *start, sector_t *size) 59 { 60 struct cdrom_multisession ms_info; 61 struct cdrom_tocentry te; 62 int res; 63 64 /* default values */ 65 *start = 0; 66 *size = sb->s_bdev->bd_inode->i_size >> 9; 67 68 if (HFSPLUS_SB(sb).session >= 0) { 69 te.cdte_track = HFSPLUS_SB(sb).session; 70 te.cdte_format = CDROM_LBA; 71 res = ioctl_by_bdev(sb->s_bdev, CDROMREADTOCENTRY, (unsigned long)&te); 72 if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) { 73 *start = (sector_t)te.cdte_addr.lba << 2; 74 return 0; 75 } 76 printk(KERN_ERR "hfs: invalid session number or type of track\n"); 77 return -EINVAL; 78 } 79 ms_info.addr_format = CDROM_LBA; 80 res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, (unsigned long)&ms_info); 81 if (!res && ms_info.xa_flag) 82 *start = (sector_t)ms_info.addr.lba << 2; 83 return 0; 84 } 85 86 /* Find the volume header and fill in some minimum bits in superblock */ 87 /* Takes in super block, returns true if good data read */ 88 int hfsplus_read_wrapper(struct super_block *sb) 89 { 90 struct buffer_head *bh; 91 struct hfsplus_vh *vhdr; 92 struct hfsplus_wd wd; 93 sector_t part_start, part_size; 94 u32 blocksize; 95 96 blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE); 97 if (!blocksize) 98 return -EINVAL; 99 100 if (hfsplus_get_last_session(sb, &part_start, &part_size)) 101 return -EINVAL; 102 if ((u64)part_start + part_size > 0x100000000ULL) { 103 pr_err("hfs: volumes larger than 2TB are not supported yet\n"); 104 return -EINVAL; 105 } 106 while (1) { 107 bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr); 108 if (!bh) 109 return -EIO; 110 111 if (vhdr->signature == cpu_to_be16(HFSP_WRAP_MAGIC)) { 112 if (!hfsplus_read_mdb(vhdr, &wd)) 113 goto error; 114 wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT; 115 part_start += wd.ablk_start + wd.embed_start * wd.ablk_size; 116 part_size = wd.embed_count * wd.ablk_size; 117 brelse(bh); 118 bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr); 119 if (!bh) 120 return -EIO; 121 } 122 if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIG)) 123 break; 124 if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) { 125 HFSPLUS_SB(sb).flags |= HFSPLUS_SB_HFSX; 126 break; 127 } 128 brelse(bh); 129 130 /* check for a partition block 131 * (should do this only for cdrom/loop though) 132 */ 133 if (hfs_part_find(sb, &part_start, &part_size)) 134 return -EINVAL; 135 } 136 137 blocksize = be32_to_cpu(vhdr->blocksize); 138 brelse(bh); 139 140 /* block size must be at least as large as a sector 141 * and a multiple of 2 142 */ 143 if (blocksize < HFSPLUS_SECTOR_SIZE || 144 ((blocksize - 1) & blocksize)) 145 return -EINVAL; 146 HFSPLUS_SB(sb).alloc_blksz = blocksize; 147 HFSPLUS_SB(sb).alloc_blksz_shift = 0; 148 while ((blocksize >>= 1) != 0) 149 HFSPLUS_SB(sb).alloc_blksz_shift++; 150 blocksize = min(HFSPLUS_SB(sb).alloc_blksz, (u32)PAGE_SIZE); 151 152 /* align block size to block offset */ 153 while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1)) 154 blocksize >>= 1; 155 156 if (sb_set_blocksize(sb, blocksize) != blocksize) { 157 printk(KERN_ERR "hfs: unable to set blocksize to %u!\n", blocksize); 158 return -EINVAL; 159 } 160 161 HFSPLUS_SB(sb).blockoffset = part_start >> 162 (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT); 163 HFSPLUS_SB(sb).sect_count = part_size; 164 HFSPLUS_SB(sb).fs_shift = HFSPLUS_SB(sb).alloc_blksz_shift - 165 sb->s_blocksize_bits; 166 167 bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr); 168 if (!bh) 169 return -EIO; 170 171 /* should still be the same... */ 172 if (vhdr->signature != (HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX ? 173 cpu_to_be16(HFSPLUS_VOLHEAD_SIGX) : 174 cpu_to_be16(HFSPLUS_VOLHEAD_SIG))) 175 goto error; 176 HFSPLUS_SB(sb).s_vhbh = bh; 177 HFSPLUS_SB(sb).s_vhdr = vhdr; 178 179 return 0; 180 error: 181 brelse(bh); 182 return -EINVAL; 183 } 184