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