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 void hfsplus_end_io_sync(struct bio *bio, int err) 28 { 29 if (err) 30 clear_bit(BIO_UPTODATE, &bio->bi_flags); 31 complete(bio->bi_private); 32 } 33 34 /* 35 * hfsplus_submit_bio - Perfrom block I/O 36 * @sb: super block of volume for I/O 37 * @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes 38 * @buf: buffer for I/O 39 * @data: output pointer for location of requested data 40 * @rw: direction of I/O 41 * 42 * The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than 43 * HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads 44 * @data will return a pointer to the start of the requested sector, 45 * which may not be the same location as @buf. 46 * 47 * If @sector is not aligned to the bdev logical block size it will 48 * be rounded down. For writes this means that @buf should contain data 49 * that starts at the rounded-down address. As long as the data was 50 * read using hfsplus_submit_bio() and the same buffer is used things 51 * will work correctly. 52 */ 53 int hfsplus_submit_bio(struct super_block *sb, sector_t sector, 54 void *buf, void **data, int rw) 55 { 56 DECLARE_COMPLETION_ONSTACK(wait); 57 struct bio *bio; 58 int ret = 0; 59 u64 io_size; 60 loff_t start; 61 int offset; 62 63 /* 64 * Align sector to hardware sector size and find offset. We 65 * assume that io_size is a power of two, which _should_ 66 * be true. 67 */ 68 io_size = hfsplus_min_io_size(sb); 69 start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT; 70 offset = start & (io_size - 1); 71 sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1); 72 73 bio = bio_alloc(GFP_NOIO, 1); 74 bio->bi_sector = sector; 75 bio->bi_bdev = sb->s_bdev; 76 bio->bi_end_io = hfsplus_end_io_sync; 77 bio->bi_private = &wait; 78 79 if (!(rw & WRITE) && data) 80 *data = (u8 *)buf + offset; 81 82 while (io_size > 0) { 83 unsigned int page_offset = offset_in_page(buf); 84 unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset, 85 io_size); 86 87 ret = bio_add_page(bio, virt_to_page(buf), len, page_offset); 88 if (ret != len) { 89 ret = -EIO; 90 goto out; 91 } 92 io_size -= len; 93 buf = (u8 *)buf + len; 94 } 95 96 submit_bio(rw, bio); 97 wait_for_completion(&wait); 98 99 if (!bio_flagged(bio, BIO_UPTODATE)) 100 ret = -EIO; 101 102 out: 103 bio_put(bio); 104 return ret < 0 ? ret : 0; 105 } 106 107 static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd) 108 { 109 u32 extent; 110 u16 attrib; 111 __be16 sig; 112 113 sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG); 114 if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) && 115 sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) 116 return 0; 117 118 attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB)); 119 if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) || 120 !(attrib & HFSP_WRAP_ATTRIB_SPARED)) 121 return 0; 122 123 wd->ablk_size = 124 be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE)); 125 if (wd->ablk_size < HFSPLUS_SECTOR_SIZE) 126 return 0; 127 if (wd->ablk_size % HFSPLUS_SECTOR_SIZE) 128 return 0; 129 wd->ablk_start = 130 be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART)); 131 132 extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT); 133 wd->embed_start = (extent >> 16) & 0xFFFF; 134 wd->embed_count = extent & 0xFFFF; 135 136 return 1; 137 } 138 139 static int hfsplus_get_last_session(struct super_block *sb, 140 sector_t *start, sector_t *size) 141 { 142 struct cdrom_multisession ms_info; 143 struct cdrom_tocentry te; 144 int res; 145 146 /* default values */ 147 *start = 0; 148 *size = sb->s_bdev->bd_inode->i_size >> 9; 149 150 if (HFSPLUS_SB(sb)->session >= 0) { 151 te.cdte_track = HFSPLUS_SB(sb)->session; 152 te.cdte_format = CDROM_LBA; 153 res = ioctl_by_bdev(sb->s_bdev, 154 CDROMREADTOCENTRY, (unsigned long)&te); 155 if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) { 156 *start = (sector_t)te.cdte_addr.lba << 2; 157 return 0; 158 } 159 printk(KERN_ERR "hfs: invalid session number or type of track\n"); 160 return -EINVAL; 161 } 162 ms_info.addr_format = CDROM_LBA; 163 res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, 164 (unsigned long)&ms_info); 165 if (!res && ms_info.xa_flag) 166 *start = (sector_t)ms_info.addr.lba << 2; 167 return 0; 168 } 169 170 /* Find the volume header and fill in some minimum bits in superblock */ 171 /* Takes in super block, returns true if good data read */ 172 int hfsplus_read_wrapper(struct super_block *sb) 173 { 174 struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); 175 struct hfsplus_wd wd; 176 sector_t part_start, part_size; 177 u32 blocksize; 178 int error = 0; 179 180 error = -EINVAL; 181 blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE); 182 if (!blocksize) 183 goto out; 184 185 if (hfsplus_get_last_session(sb, &part_start, &part_size)) 186 goto out; 187 188 error = -ENOMEM; 189 sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); 190 if (!sbi->s_vhdr_buf) 191 goto out; 192 sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); 193 if (!sbi->s_backup_vhdr_buf) 194 goto out_free_vhdr; 195 196 reread: 197 error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, 198 sbi->s_vhdr_buf, (void **)&sbi->s_vhdr, 199 READ); 200 if (error) 201 goto out_free_backup_vhdr; 202 203 error = -EINVAL; 204 switch (sbi->s_vhdr->signature) { 205 case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX): 206 set_bit(HFSPLUS_SB_HFSX, &sbi->flags); 207 /*FALLTHRU*/ 208 case cpu_to_be16(HFSPLUS_VOLHEAD_SIG): 209 break; 210 case cpu_to_be16(HFSP_WRAP_MAGIC): 211 if (!hfsplus_read_mdb(sbi->s_vhdr, &wd)) 212 goto out_free_backup_vhdr; 213 wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT; 214 part_start += (sector_t)wd.ablk_start + 215 (sector_t)wd.embed_start * wd.ablk_size; 216 part_size = (sector_t)wd.embed_count * wd.ablk_size; 217 goto reread; 218 default: 219 /* 220 * Check for a partition block. 221 * 222 * (should do this only for cdrom/loop though) 223 */ 224 if (hfs_part_find(sb, &part_start, &part_size)) 225 goto out_free_backup_vhdr; 226 goto reread; 227 } 228 229 error = hfsplus_submit_bio(sb, part_start + part_size - 2, 230 sbi->s_backup_vhdr_buf, 231 (void **)&sbi->s_backup_vhdr, READ); 232 if (error) 233 goto out_free_backup_vhdr; 234 235 error = -EINVAL; 236 if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) { 237 printk(KERN_WARNING 238 "hfs: invalid secondary volume header\n"); 239 goto out_free_backup_vhdr; 240 } 241 242 blocksize = be32_to_cpu(sbi->s_vhdr->blocksize); 243 244 /* 245 * Block size must be at least as large as a sector and a multiple of 2. 246 */ 247 if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize)) 248 goto out_free_backup_vhdr; 249 sbi->alloc_blksz = blocksize; 250 sbi->alloc_blksz_shift = 0; 251 while ((blocksize >>= 1) != 0) 252 sbi->alloc_blksz_shift++; 253 blocksize = min(sbi->alloc_blksz, (u32)PAGE_SIZE); 254 255 /* 256 * Align block size to block offset. 257 */ 258 while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1)) 259 blocksize >>= 1; 260 261 if (sb_set_blocksize(sb, blocksize) != blocksize) { 262 printk(KERN_ERR "hfs: unable to set blocksize to %u!\n", 263 blocksize); 264 goto out_free_backup_vhdr; 265 } 266 267 sbi->blockoffset = 268 part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT); 269 sbi->part_start = part_start; 270 sbi->sect_count = part_size; 271 sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits; 272 return 0; 273 274 out_free_backup_vhdr: 275 kfree(sbi->s_backup_vhdr_buf); 276 out_free_vhdr: 277 kfree(sbi->s_vhdr_buf); 278 out: 279 return error; 280 } 281