1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/hfsplus/wrapper.c 4 * 5 * Copyright (C) 2001 6 * Brad Boyer (flar@allandria.com) 7 * (C) 2003 Ardis Technologies <roman@ardistech.com> 8 * 9 * Handling of HFS wrappers around HFS+ volumes 10 */ 11 12 #include <linux/fs.h> 13 #include <linux/blkdev.h> 14 #include <linux/cdrom.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(sb->s_bdev, 1, op | op_flags, GFP_NOIO); 67 bio->bi_iter.bi_sector = sector; 68 69 if (op != 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(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_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk); 128 129 /* default values */ 130 *start = 0; 131 *size = bdev_nr_sectors(sb->s_bdev); 132 133 if (HFSPLUS_SB(sb)->session >= 0) { 134 struct cdrom_tocentry te; 135 136 if (!cdi) 137 return -EINVAL; 138 139 te.cdte_track = HFSPLUS_SB(sb)->session; 140 te.cdte_format = CDROM_LBA; 141 if (cdrom_read_tocentry(cdi, &te) || 142 (te.cdte_ctrl & CDROM_DATA_TRACK) != 4) { 143 pr_err("invalid session number or type of track\n"); 144 return -EINVAL; 145 } 146 *start = (sector_t)te.cdte_addr.lba << 2; 147 } else if (cdi) { 148 struct cdrom_multisession ms_info; 149 150 ms_info.addr_format = CDROM_LBA; 151 if (cdrom_multisession(cdi, &ms_info) == 0 && ms_info.xa_flag) 152 *start = (sector_t)ms_info.addr.lba << 2; 153 } 154 155 return 0; 156 } 157 158 /* Find the volume header and fill in some minimum bits in superblock */ 159 /* Takes in super block, returns true if good data read */ 160 int hfsplus_read_wrapper(struct super_block *sb) 161 { 162 struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); 163 struct hfsplus_wd wd; 164 sector_t part_start, part_size; 165 u32 blocksize; 166 int error = 0; 167 168 error = -EINVAL; 169 blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE); 170 if (!blocksize) 171 goto out; 172 173 if (hfsplus_get_last_session(sb, &part_start, &part_size)) 174 goto out; 175 176 error = -ENOMEM; 177 sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); 178 if (!sbi->s_vhdr_buf) 179 goto out; 180 sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); 181 if (!sbi->s_backup_vhdr_buf) 182 goto out_free_vhdr; 183 184 reread: 185 error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, 186 sbi->s_vhdr_buf, (void **)&sbi->s_vhdr, 187 REQ_OP_READ, 0); 188 if (error) 189 goto out_free_backup_vhdr; 190 191 error = -EINVAL; 192 switch (sbi->s_vhdr->signature) { 193 case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX): 194 set_bit(HFSPLUS_SB_HFSX, &sbi->flags); 195 fallthrough; 196 case cpu_to_be16(HFSPLUS_VOLHEAD_SIG): 197 break; 198 case cpu_to_be16(HFSP_WRAP_MAGIC): 199 if (!hfsplus_read_mdb(sbi->s_vhdr, &wd)) 200 goto out_free_backup_vhdr; 201 wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT; 202 part_start += (sector_t)wd.ablk_start + 203 (sector_t)wd.embed_start * wd.ablk_size; 204 part_size = (sector_t)wd.embed_count * wd.ablk_size; 205 goto reread; 206 default: 207 /* 208 * Check for a partition block. 209 * 210 * (should do this only for cdrom/loop though) 211 */ 212 if (hfs_part_find(sb, &part_start, &part_size)) 213 goto out_free_backup_vhdr; 214 goto reread; 215 } 216 217 error = hfsplus_submit_bio(sb, part_start + part_size - 2, 218 sbi->s_backup_vhdr_buf, 219 (void **)&sbi->s_backup_vhdr, REQ_OP_READ, 220 0); 221 if (error) 222 goto out_free_backup_vhdr; 223 224 error = -EINVAL; 225 if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) { 226 pr_warn("invalid secondary volume header\n"); 227 goto out_free_backup_vhdr; 228 } 229 230 blocksize = be32_to_cpu(sbi->s_vhdr->blocksize); 231 232 /* 233 * Block size must be at least as large as a sector and a multiple of 2. 234 */ 235 if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize)) 236 goto out_free_backup_vhdr; 237 sbi->alloc_blksz = blocksize; 238 sbi->alloc_blksz_shift = ilog2(blocksize); 239 blocksize = min_t(u32, sbi->alloc_blksz, PAGE_SIZE); 240 241 /* 242 * Align block size to block offset. 243 */ 244 while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1)) 245 blocksize >>= 1; 246 247 if (sb_set_blocksize(sb, blocksize) != blocksize) { 248 pr_err("unable to set blocksize to %u!\n", blocksize); 249 goto out_free_backup_vhdr; 250 } 251 252 sbi->blockoffset = 253 part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT); 254 sbi->part_start = part_start; 255 sbi->sect_count = part_size; 256 sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits; 257 return 0; 258 259 out_free_backup_vhdr: 260 kfree(sbi->s_backup_vhdr_buf); 261 out_free_vhdr: 262 kfree(sbi->s_vhdr_buf); 263 out: 264 return error; 265 } 266