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, blk_opf_t opf) 49 { 50 const enum req_op op = opf & REQ_OP_MASK; 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(sb->s_bdev, 1, opf, GFP_NOIO); 68 bio->bi_iter.bi_sector = sector; 69 70 if (op != REQ_OP_WRITE && data) 71 *data = (u8 *)buf + offset; 72 73 while (io_size > 0) { 74 unsigned int page_offset = offset_in_page(buf); 75 unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset, 76 io_size); 77 78 ret = bio_add_page(bio, virt_to_page(buf), len, page_offset); 79 if (ret != len) { 80 ret = -EIO; 81 goto out; 82 } 83 io_size -= len; 84 buf = (u8 *)buf + len; 85 } 86 87 ret = submit_bio_wait(bio); 88 out: 89 bio_put(bio); 90 return ret < 0 ? ret : 0; 91 } 92 93 static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd) 94 { 95 u32 extent; 96 u16 attrib; 97 __be16 sig; 98 99 sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG); 100 if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) && 101 sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) 102 return 0; 103 104 attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB)); 105 if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) || 106 !(attrib & HFSP_WRAP_ATTRIB_SPARED)) 107 return 0; 108 109 wd->ablk_size = 110 be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE)); 111 if (wd->ablk_size < HFSPLUS_SECTOR_SIZE) 112 return 0; 113 if (wd->ablk_size % HFSPLUS_SECTOR_SIZE) 114 return 0; 115 wd->ablk_start = 116 be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART)); 117 118 extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT); 119 wd->embed_start = (extent >> 16) & 0xFFFF; 120 wd->embed_count = extent & 0xFFFF; 121 122 return 1; 123 } 124 125 static int hfsplus_get_last_session(struct super_block *sb, 126 sector_t *start, sector_t *size) 127 { 128 struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk); 129 130 /* default values */ 131 *start = 0; 132 *size = bdev_nr_sectors(sb->s_bdev); 133 134 if (HFSPLUS_SB(sb)->session >= 0) { 135 struct cdrom_tocentry te; 136 137 if (!cdi) 138 return -EINVAL; 139 140 te.cdte_track = HFSPLUS_SB(sb)->session; 141 te.cdte_format = CDROM_LBA; 142 if (cdrom_read_tocentry(cdi, &te) || 143 (te.cdte_ctrl & CDROM_DATA_TRACK) != 4) { 144 pr_err("invalid session number or type of track\n"); 145 return -EINVAL; 146 } 147 *start = (sector_t)te.cdte_addr.lba << 2; 148 } else if (cdi) { 149 struct cdrom_multisession ms_info; 150 151 ms_info.addr_format = CDROM_LBA; 152 if (cdrom_multisession(cdi, &ms_info) == 0 && ms_info.xa_flag) 153 *start = (sector_t)ms_info.addr.lba << 2; 154 } 155 156 return 0; 157 } 158 159 /* Find the volume header and fill in some minimum bits in superblock */ 160 /* Takes in super block, returns true if good data read */ 161 int hfsplus_read_wrapper(struct super_block *sb) 162 { 163 struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); 164 struct hfsplus_wd wd; 165 sector_t part_start, part_size; 166 u32 blocksize; 167 int error = 0; 168 169 error = -EINVAL; 170 blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE); 171 if (!blocksize) 172 goto out; 173 174 sbi->min_io_size = blocksize; 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); 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 if (error) 224 goto out_free_backup_vhdr; 225 226 error = -EINVAL; 227 if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) { 228 pr_warn("invalid secondary volume header\n"); 229 goto out_free_backup_vhdr; 230 } 231 232 blocksize = be32_to_cpu(sbi->s_vhdr->blocksize); 233 234 /* 235 * Block size must be at least as large as a sector and a multiple of 2. 236 */ 237 if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize)) 238 goto out_free_backup_vhdr; 239 sbi->alloc_blksz = blocksize; 240 sbi->alloc_blksz_shift = ilog2(blocksize); 241 blocksize = min_t(u32, sbi->alloc_blksz, PAGE_SIZE); 242 243 /* 244 * Align block size to block offset. 245 */ 246 while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1)) 247 blocksize >>= 1; 248 249 if (sb_set_blocksize(sb, blocksize) != blocksize) { 250 pr_err("unable to set blocksize to %u!\n", blocksize); 251 goto out_free_backup_vhdr; 252 } 253 254 sbi->blockoffset = 255 part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT); 256 sbi->part_start = part_start; 257 sbi->sect_count = part_size; 258 sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits; 259 return 0; 260 261 out_free_backup_vhdr: 262 kfree(sbi->s_backup_vhdr_buf); 263 out_free_vhdr: 264 kfree(sbi->s_vhdr_buf); 265 out: 266 return error; 267 } 268