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 /** 28 * hfsplus_submit_bio - Perform block I/O 29 * @sb: super block of volume for I/O 30 * @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes 31 * @buf: buffer for I/O 32 * @data: output pointer for location of requested data 33 * @op: direction of I/O 34 * @op_flags: request op flags 35 * 36 * The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than 37 * HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads 38 * @data will return a pointer to the start of the requested sector, 39 * which may not be the same location as @buf. 40 * 41 * If @sector is not aligned to the bdev logical block size it will 42 * be rounded down. For writes this means that @buf should contain data 43 * that starts at the rounded-down address. As long as the data was 44 * read using hfsplus_submit_bio() and the same buffer is used things 45 * will work correctly. 46 */ 47 int hfsplus_submit_bio(struct super_block *sb, sector_t sector, 48 void *buf, void **data, int op, int op_flags) 49 { 50 struct bio *bio; 51 int ret = 0; 52 u64 io_size; 53 loff_t start; 54 int offset; 55 56 /* 57 * Align sector to hardware sector size and find offset. We 58 * assume that io_size is a power of two, which _should_ 59 * be true. 60 */ 61 io_size = hfsplus_min_io_size(sb); 62 start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT; 63 offset = start & (io_size - 1); 64 sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1); 65 66 bio = bio_alloc(GFP_NOIO, 1); 67 bio->bi_iter.bi_sector = sector; 68 bio_set_dev(bio, sb->s_bdev); 69 bio_set_op_attrs(bio, op, op_flags); 70 71 if (op != WRITE && data) 72 *data = (u8 *)buf + offset; 73 74 while (io_size > 0) { 75 unsigned int page_offset = offset_in_page(buf); 76 unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset, 77 io_size); 78 79 ret = bio_add_page(bio, virt_to_page(buf), len, page_offset); 80 if (ret != len) { 81 ret = -EIO; 82 goto out; 83 } 84 io_size -= len; 85 buf = (u8 *)buf + len; 86 } 87 88 ret = submit_bio_wait(bio); 89 out: 90 bio_put(bio); 91 return ret < 0 ? ret : 0; 92 } 93 94 static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd) 95 { 96 u32 extent; 97 u16 attrib; 98 __be16 sig; 99 100 sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG); 101 if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) && 102 sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) 103 return 0; 104 105 attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB)); 106 if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) || 107 !(attrib & HFSP_WRAP_ATTRIB_SPARED)) 108 return 0; 109 110 wd->ablk_size = 111 be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE)); 112 if (wd->ablk_size < HFSPLUS_SECTOR_SIZE) 113 return 0; 114 if (wd->ablk_size % HFSPLUS_SECTOR_SIZE) 115 return 0; 116 wd->ablk_start = 117 be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART)); 118 119 extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT); 120 wd->embed_start = (extent >> 16) & 0xFFFF; 121 wd->embed_count = extent & 0xFFFF; 122 123 return 1; 124 } 125 126 static int hfsplus_get_last_session(struct super_block *sb, 127 sector_t *start, sector_t *size) 128 { 129 struct cdrom_multisession ms_info; 130 struct cdrom_tocentry te; 131 int res; 132 133 /* default values */ 134 *start = 0; 135 *size = i_size_read(sb->s_bdev->bd_inode) >> 9; 136 137 if (HFSPLUS_SB(sb)->session >= 0) { 138 te.cdte_track = HFSPLUS_SB(sb)->session; 139 te.cdte_format = CDROM_LBA; 140 res = ioctl_by_bdev(sb->s_bdev, 141 CDROMREADTOCENTRY, (unsigned long)&te); 142 if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) { 143 *start = (sector_t)te.cdte_addr.lba << 2; 144 return 0; 145 } 146 pr_err("invalid session number or type of track\n"); 147 return -EINVAL; 148 } 149 ms_info.addr_format = CDROM_LBA; 150 res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, 151 (unsigned long)&ms_info); 152 if (!res && ms_info.xa_flag) 153 *start = (sector_t)ms_info.addr.lba << 2; 154 return 0; 155 } 156 157 /* Find the volume header and fill in some minimum bits in superblock */ 158 /* Takes in super block, returns true if good data read */ 159 int hfsplus_read_wrapper(struct super_block *sb) 160 { 161 struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); 162 struct hfsplus_wd wd; 163 sector_t part_start, part_size; 164 u32 blocksize; 165 int error = 0; 166 167 error = -EINVAL; 168 blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE); 169 if (!blocksize) 170 goto out; 171 172 if (hfsplus_get_last_session(sb, &part_start, &part_size)) 173 goto out; 174 175 error = -ENOMEM; 176 sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); 177 if (!sbi->s_vhdr_buf) 178 goto out; 179 sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); 180 if (!sbi->s_backup_vhdr_buf) 181 goto out_free_vhdr; 182 183 reread: 184 error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, 185 sbi->s_vhdr_buf, (void **)&sbi->s_vhdr, 186 REQ_OP_READ, 0); 187 if (error) 188 goto out_free_backup_vhdr; 189 190 error = -EINVAL; 191 switch (sbi->s_vhdr->signature) { 192 case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX): 193 set_bit(HFSPLUS_SB_HFSX, &sbi->flags); 194 /*FALLTHRU*/ 195 case cpu_to_be16(HFSPLUS_VOLHEAD_SIG): 196 break; 197 case cpu_to_be16(HFSP_WRAP_MAGIC): 198 if (!hfsplus_read_mdb(sbi->s_vhdr, &wd)) 199 goto out_free_backup_vhdr; 200 wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT; 201 part_start += (sector_t)wd.ablk_start + 202 (sector_t)wd.embed_start * wd.ablk_size; 203 part_size = (sector_t)wd.embed_count * wd.ablk_size; 204 goto reread; 205 default: 206 /* 207 * Check for a partition block. 208 * 209 * (should do this only for cdrom/loop though) 210 */ 211 if (hfs_part_find(sb, &part_start, &part_size)) 212 goto out_free_backup_vhdr; 213 goto reread; 214 } 215 216 error = hfsplus_submit_bio(sb, part_start + part_size - 2, 217 sbi->s_backup_vhdr_buf, 218 (void **)&sbi->s_backup_vhdr, REQ_OP_READ, 219 0); 220 if (error) 221 goto out_free_backup_vhdr; 222 223 error = -EINVAL; 224 if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) { 225 pr_warn("invalid secondary volume header\n"); 226 goto out_free_backup_vhdr; 227 } 228 229 blocksize = be32_to_cpu(sbi->s_vhdr->blocksize); 230 231 /* 232 * Block size must be at least as large as a sector and a multiple of 2. 233 */ 234 if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize)) 235 goto out_free_backup_vhdr; 236 sbi->alloc_blksz = blocksize; 237 sbi->alloc_blksz_shift = ilog2(blocksize); 238 blocksize = min_t(u32, sbi->alloc_blksz, PAGE_SIZE); 239 240 /* 241 * Align block size to block offset. 242 */ 243 while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1)) 244 blocksize >>= 1; 245 246 if (sb_set_blocksize(sb, blocksize) != blocksize) { 247 pr_err("unable to set blocksize to %u!\n", blocksize); 248 goto out_free_backup_vhdr; 249 } 250 251 sbi->blockoffset = 252 part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT); 253 sbi->part_start = part_start; 254 sbi->sect_count = part_size; 255 sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits; 256 return 0; 257 258 out_free_backup_vhdr: 259 kfree(sbi->s_backup_vhdr_buf); 260 out_free_vhdr: 261 kfree(sbi->s_vhdr_buf); 262 out: 263 return error; 264 } 265