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