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 <linux/genhd.h> 16 #include <asm/unaligned.h> 17 18 #include "hfsplus_fs.h" 19 #include "hfsplus_raw.h" 20 21 struct hfsplus_wd { 22 u32 ablk_size; 23 u16 ablk_start; 24 u16 embed_start; 25 u16 embed_count; 26 }; 27 28 /** 29 * hfsplus_submit_bio - Perform block I/O 30 * @sb: super block of volume for I/O 31 * @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes 32 * @buf: buffer for I/O 33 * @data: output pointer for location of requested data 34 * @op: direction of I/O 35 * @op_flags: request op flags 36 * 37 * The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than 38 * HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads 39 * @data will return a pointer to the start of the requested sector, 40 * which may not be the same location as @buf. 41 * 42 * If @sector is not aligned to the bdev logical block size it will 43 * be rounded down. For writes this means that @buf should contain data 44 * that starts at the rounded-down address. As long as the data was 45 * read using hfsplus_submit_bio() and the same buffer is used things 46 * will work correctly. 47 */ 48 int hfsplus_submit_bio(struct super_block *sb, sector_t sector, 49 void *buf, void **data, int op, int op_flags) 50 { 51 struct bio *bio; 52 int ret = 0; 53 u64 io_size; 54 loff_t start; 55 int offset; 56 57 /* 58 * Align sector to hardware sector size and find offset. We 59 * assume that io_size is a power of two, which _should_ 60 * be true. 61 */ 62 io_size = hfsplus_min_io_size(sb); 63 start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT; 64 offset = start & (io_size - 1); 65 sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1); 66 67 bio = bio_alloc(GFP_NOIO, 1); 68 bio->bi_iter.bi_sector = sector; 69 bio_set_dev(bio, sb->s_bdev); 70 bio_set_op_attrs(bio, op, op_flags); 71 72 if (op != WRITE && data) 73 *data = (u8 *)buf + offset; 74 75 while (io_size > 0) { 76 unsigned int page_offset = offset_in_page(buf); 77 unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset, 78 io_size); 79 80 ret = bio_add_page(bio, virt_to_page(buf), len, page_offset); 81 if (ret != len) { 82 ret = -EIO; 83 goto out; 84 } 85 io_size -= len; 86 buf = (u8 *)buf + len; 87 } 88 89 ret = submit_bio_wait(bio); 90 out: 91 bio_put(bio); 92 return ret < 0 ? ret : 0; 93 } 94 95 static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd) 96 { 97 u32 extent; 98 u16 attrib; 99 __be16 sig; 100 101 sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG); 102 if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) && 103 sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) 104 return 0; 105 106 attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB)); 107 if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) || 108 !(attrib & HFSP_WRAP_ATTRIB_SPARED)) 109 return 0; 110 111 wd->ablk_size = 112 be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE)); 113 if (wd->ablk_size < HFSPLUS_SECTOR_SIZE) 114 return 0; 115 if (wd->ablk_size % HFSPLUS_SECTOR_SIZE) 116 return 0; 117 wd->ablk_start = 118 be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART)); 119 120 extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT); 121 wd->embed_start = (extent >> 16) & 0xFFFF; 122 wd->embed_count = extent & 0xFFFF; 123 124 return 1; 125 } 126 127 static int hfsplus_get_last_session(struct super_block *sb, 128 sector_t *start, sector_t *size) 129 { 130 struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk); 131 132 /* default values */ 133 *start = 0; 134 *size = i_size_read(sb->s_bdev->bd_inode) >> 9; 135 136 if (HFSPLUS_SB(sb)->session >= 0) { 137 struct cdrom_tocentry te; 138 139 if (!cdi) 140 return -EINVAL; 141 142 te.cdte_track = HFSPLUS_SB(sb)->session; 143 te.cdte_format = CDROM_LBA; 144 if (cdrom_read_tocentry(cdi, &te) || 145 (te.cdte_ctrl & CDROM_DATA_TRACK) != 4) { 146 pr_err("invalid session number or type of track\n"); 147 return -EINVAL; 148 } 149 *start = (sector_t)te.cdte_addr.lba << 2; 150 } else if (cdi) { 151 struct cdrom_multisession ms_info; 152 153 ms_info.addr_format = CDROM_LBA; 154 if (cdrom_multisession(cdi, &ms_info) == 0 && ms_info.xa_flag) 155 *start = (sector_t)ms_info.addr.lba << 2; 156 } 157 158 return 0; 159 } 160 161 /* Find the volume header and fill in some minimum bits in superblock */ 162 /* Takes in super block, returns true if good data read */ 163 int hfsplus_read_wrapper(struct super_block *sb) 164 { 165 struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); 166 struct hfsplus_wd wd; 167 sector_t part_start, part_size; 168 u32 blocksize; 169 int error = 0; 170 171 error = -EINVAL; 172 blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE); 173 if (!blocksize) 174 goto out; 175 176 if (hfsplus_get_last_session(sb, &part_start, &part_size)) 177 goto out; 178 179 error = -ENOMEM; 180 sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); 181 if (!sbi->s_vhdr_buf) 182 goto out; 183 sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); 184 if (!sbi->s_backup_vhdr_buf) 185 goto out_free_vhdr; 186 187 reread: 188 error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, 189 sbi->s_vhdr_buf, (void **)&sbi->s_vhdr, 190 REQ_OP_READ, 0); 191 if (error) 192 goto out_free_backup_vhdr; 193 194 error = -EINVAL; 195 switch (sbi->s_vhdr->signature) { 196 case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX): 197 set_bit(HFSPLUS_SB_HFSX, &sbi->flags); 198 fallthrough; 199 case cpu_to_be16(HFSPLUS_VOLHEAD_SIG): 200 break; 201 case cpu_to_be16(HFSP_WRAP_MAGIC): 202 if (!hfsplus_read_mdb(sbi->s_vhdr, &wd)) 203 goto out_free_backup_vhdr; 204 wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT; 205 part_start += (sector_t)wd.ablk_start + 206 (sector_t)wd.embed_start * wd.ablk_size; 207 part_size = (sector_t)wd.embed_count * wd.ablk_size; 208 goto reread; 209 default: 210 /* 211 * Check for a partition block. 212 * 213 * (should do this only for cdrom/loop though) 214 */ 215 if (hfs_part_find(sb, &part_start, &part_size)) 216 goto out_free_backup_vhdr; 217 goto reread; 218 } 219 220 error = hfsplus_submit_bio(sb, part_start + part_size - 2, 221 sbi->s_backup_vhdr_buf, 222 (void **)&sbi->s_backup_vhdr, REQ_OP_READ, 223 0); 224 if (error) 225 goto out_free_backup_vhdr; 226 227 error = -EINVAL; 228 if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) { 229 pr_warn("invalid secondary volume header\n"); 230 goto out_free_backup_vhdr; 231 } 232 233 blocksize = be32_to_cpu(sbi->s_vhdr->blocksize); 234 235 /* 236 * Block size must be at least as large as a sector and a multiple of 2. 237 */ 238 if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize)) 239 goto out_free_backup_vhdr; 240 sbi->alloc_blksz = blocksize; 241 sbi->alloc_blksz_shift = ilog2(blocksize); 242 blocksize = min_t(u32, sbi->alloc_blksz, PAGE_SIZE); 243 244 /* 245 * Align block size to block offset. 246 */ 247 while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1)) 248 blocksize >>= 1; 249 250 if (sb_set_blocksize(sb, blocksize) != blocksize) { 251 pr_err("unable to set blocksize to %u!\n", blocksize); 252 goto out_free_backup_vhdr; 253 } 254 255 sbi->blockoffset = 256 part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT); 257 sbi->part_start = part_start; 258 sbi->sect_count = part_size; 259 sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits; 260 return 0; 261 262 out_free_backup_vhdr: 263 kfree(sbi->s_backup_vhdr_buf); 264 out_free_vhdr: 265 kfree(sbi->s_vhdr_buf); 266 out: 267 return error; 268 } 269