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 <linux/version.h> 16 #include <asm/unaligned.h> 17 18 #include "hfsplus_fs.h" 19 #include "hfsplus_raw.h" 20 21 struct hfsplus_wd { 22 u32 ablk_size; 23 u16 ablk_start; 24 u16 embed_start; 25 u16 embed_count; 26 }; 27 28 static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd) 29 { 30 u32 extent; 31 u16 attrib; 32 33 if (be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG)) != HFSPLUS_VOLHEAD_SIG) 34 return 0; 35 36 attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB)); 37 if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) || 38 !(attrib & HFSP_WRAP_ATTRIB_SPARED)) 39 return 0; 40 41 wd->ablk_size = be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE)); 42 if (wd->ablk_size < HFSPLUS_SECTOR_SIZE) 43 return 0; 44 if (wd->ablk_size % HFSPLUS_SECTOR_SIZE) 45 return 0; 46 wd->ablk_start = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART)); 47 48 extent = be32_to_cpu(get_unaligned((__be32 *)(bufptr + HFSP_WRAPOFF_EMBEDEXT))); 49 wd->embed_start = (extent >> 16) & 0xFFFF; 50 wd->embed_count = extent & 0xFFFF; 51 52 return 1; 53 } 54 55 static int hfsplus_get_last_session(struct super_block *sb, 56 sector_t *start, sector_t *size) 57 { 58 struct cdrom_multisession ms_info; 59 struct cdrom_tocentry te; 60 int res; 61 62 /* default values */ 63 *start = 0; 64 *size = sb->s_bdev->bd_inode->i_size >> 9; 65 66 if (HFSPLUS_SB(sb).session >= 0) { 67 te.cdte_track = HFSPLUS_SB(sb).session; 68 te.cdte_format = CDROM_LBA; 69 res = ioctl_by_bdev(sb->s_bdev, CDROMREADTOCENTRY, (unsigned long)&te); 70 if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) { 71 *start = (sector_t)te.cdte_addr.lba << 2; 72 return 0; 73 } 74 printk(KERN_ERR "HFS: Invalid session number or type of track\n"); 75 return -EINVAL; 76 } 77 ms_info.addr_format = CDROM_LBA; 78 res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, (unsigned long)&ms_info); 79 if (!res && ms_info.xa_flag) 80 *start = (sector_t)ms_info.addr.lba << 2; 81 return 0; 82 } 83 84 /* Find the volume header and fill in some minimum bits in superblock */ 85 /* Takes in super block, returns true if good data read */ 86 int hfsplus_read_wrapper(struct super_block *sb) 87 { 88 struct buffer_head *bh; 89 struct hfsplus_vh *vhdr; 90 struct hfsplus_wd wd; 91 sector_t part_start, part_size; 92 u32 blocksize; 93 94 blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE); 95 if (!blocksize) 96 return -EINVAL; 97 98 if (hfsplus_get_last_session(sb, &part_start, &part_size)) 99 return -EINVAL; 100 while (1) { 101 bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr); 102 if (!bh) 103 return -EIO; 104 105 if (vhdr->signature == cpu_to_be16(HFSP_WRAP_MAGIC)) { 106 if (!hfsplus_read_mdb(vhdr, &wd)) 107 goto error; 108 wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT; 109 part_start += wd.ablk_start + wd.embed_start * wd.ablk_size; 110 part_size = wd.embed_count * wd.ablk_size; 111 brelse(bh); 112 bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr); 113 if (!bh) 114 return -EIO; 115 } 116 if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIG)) 117 break; 118 brelse(bh); 119 120 /* check for a partition block 121 * (should do this only for cdrom/loop though) 122 */ 123 if (hfs_part_find(sb, &part_start, &part_size)) 124 return -EINVAL; 125 } 126 127 blocksize = be32_to_cpu(vhdr->blocksize); 128 brelse(bh); 129 130 /* block size must be at least as large as a sector 131 * and a multiple of 2 132 */ 133 if (blocksize < HFSPLUS_SECTOR_SIZE || 134 ((blocksize - 1) & blocksize)) 135 return -EINVAL; 136 HFSPLUS_SB(sb).alloc_blksz = blocksize; 137 HFSPLUS_SB(sb).alloc_blksz_shift = 0; 138 while ((blocksize >>= 1) != 0) 139 HFSPLUS_SB(sb).alloc_blksz_shift++; 140 blocksize = min(HFSPLUS_SB(sb).alloc_blksz, (u32)PAGE_SIZE); 141 142 /* align block size to block offset */ 143 while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1)) 144 blocksize >>= 1; 145 146 if (sb_set_blocksize(sb, blocksize) != blocksize) { 147 printk("HFS+: unable to blocksize to %u!\n", blocksize); 148 return -EINVAL; 149 } 150 151 HFSPLUS_SB(sb).blockoffset = part_start >> 152 (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT); 153 HFSPLUS_SB(sb).sect_count = part_size; 154 HFSPLUS_SB(sb).fs_shift = HFSPLUS_SB(sb).alloc_blksz_shift - 155 sb->s_blocksize_bits; 156 157 bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr); 158 if (!bh) 159 return -EIO; 160 161 /* should still be the same... */ 162 if (be16_to_cpu(vhdr->signature) != HFSPLUS_VOLHEAD_SIG) 163 goto error; 164 HFSPLUS_SB(sb).s_vhbh = bh; 165 HFSPLUS_SB(sb).s_vhdr = vhdr; 166 167 return 0; 168 error: 169 brelse(bh); 170 return -EINVAL; 171 } 172