// SPDX-License-Identifier: GPL-2.0 /* * linux/fs/hfsplus/wrapper.c * * Copyright (C) 2001 * Brad Boyer (flar@allandria.com) * (C) 2003 Ardis Technologies <roman@ardistech.com> * * Handling of HFS wrappers around HFS+ volumes */ #include <linux/fs.h> #include <linux/blkdev.h> #include <linux/cdrom.h> #include <linux/genhd.h> #include <asm/unaligned.h> #include "hfsplus_fs.h" #include "hfsplus_raw.h" struct hfsplus_wd { u32 ablk_size; u16 ablk_start; u16 embed_start; u16 embed_count; }; /** * hfsplus_submit_bio - Perform block I/O * @sb: super block of volume for I/O * @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes * @buf: buffer for I/O * @data: output pointer for location of requested data * @op: direction of I/O * @op_flags: request op flags * * The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than * HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads * @data will return a pointer to the start of the requested sector, * which may not be the same location as @buf. * * If @sector is not aligned to the bdev logical block size it will * be rounded down. For writes this means that @buf should contain data * that starts at the rounded-down address. As long as the data was * read using hfsplus_submit_bio() and the same buffer is used things * will work correctly. */ int hfsplus_submit_bio(struct super_block *sb, sector_t sector, void *buf, void **data, int op, int op_flags) { struct bio *bio; int ret = 0; u64 io_size; loff_t start; int offset; /* * Align sector to hardware sector size and find offset. We * assume that io_size is a power of two, which _should_ * be true. */ io_size = hfsplus_min_io_size(sb); start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT; offset = start & (io_size - 1); sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1); bio = bio_alloc(GFP_NOIO, 1); bio->bi_iter.bi_sector = sector; bio_set_dev(bio, sb->s_bdev); bio_set_op_attrs(bio, op, op_flags); if (op != WRITE && data) *data = (u8 *)buf + offset; while (io_size > 0) { unsigned int page_offset = offset_in_page(buf); unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset, io_size); ret = bio_add_page(bio, virt_to_page(buf), len, page_offset); if (ret != len) { ret = -EIO; goto out; } io_size -= len; buf = (u8 *)buf + len; } ret = submit_bio_wait(bio); out: bio_put(bio); return ret < 0 ? ret : 0; } static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd) { u32 extent; u16 attrib; __be16 sig; sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG); if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) && sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) return 0; attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB)); if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) || !(attrib & HFSP_WRAP_ATTRIB_SPARED)) return 0; wd->ablk_size = be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE)); if (wd->ablk_size < HFSPLUS_SECTOR_SIZE) return 0; if (wd->ablk_size % HFSPLUS_SECTOR_SIZE) return 0; wd->ablk_start = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART)); extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT); wd->embed_start = (extent >> 16) & 0xFFFF; wd->embed_count = extent & 0xFFFF; return 1; } static int hfsplus_get_last_session(struct super_block *sb, sector_t *start, sector_t *size) { struct cdrom_multisession ms_info; struct cdrom_tocentry te; int res; /* default values */ *start = 0; *size = i_size_read(sb->s_bdev->bd_inode) >> 9; if (HFSPLUS_SB(sb)->session >= 0) { te.cdte_track = HFSPLUS_SB(sb)->session; te.cdte_format = CDROM_LBA; res = ioctl_by_bdev(sb->s_bdev, CDROMREADTOCENTRY, (unsigned long)&te); if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) { *start = (sector_t)te.cdte_addr.lba << 2; return 0; } pr_err("invalid session number or type of track\n"); return -EINVAL; } ms_info.addr_format = CDROM_LBA; res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, (unsigned long)&ms_info); if (!res && ms_info.xa_flag) *start = (sector_t)ms_info.addr.lba << 2; return 0; } /* Find the volume header and fill in some minimum bits in superblock */ /* Takes in super block, returns true if good data read */ int hfsplus_read_wrapper(struct super_block *sb) { struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); struct hfsplus_wd wd; sector_t part_start, part_size; u32 blocksize; int error = 0; error = -EINVAL; blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE); if (!blocksize) goto out; if (hfsplus_get_last_session(sb, &part_start, &part_size)) goto out; error = -ENOMEM; sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); if (!sbi->s_vhdr_buf) goto out; sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); if (!sbi->s_backup_vhdr_buf) goto out_free_vhdr; reread: error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, sbi->s_vhdr_buf, (void **)&sbi->s_vhdr, REQ_OP_READ, 0); if (error) goto out_free_backup_vhdr; error = -EINVAL; switch (sbi->s_vhdr->signature) { case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX): set_bit(HFSPLUS_SB_HFSX, &sbi->flags); /*FALLTHRU*/ case cpu_to_be16(HFSPLUS_VOLHEAD_SIG): break; case cpu_to_be16(HFSP_WRAP_MAGIC): if (!hfsplus_read_mdb(sbi->s_vhdr, &wd)) goto out_free_backup_vhdr; wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT; part_start += (sector_t)wd.ablk_start + (sector_t)wd.embed_start * wd.ablk_size; part_size = (sector_t)wd.embed_count * wd.ablk_size; goto reread; default: /* * Check for a partition block. * * (should do this only for cdrom/loop though) */ if (hfs_part_find(sb, &part_start, &part_size)) goto out_free_backup_vhdr; goto reread; } error = hfsplus_submit_bio(sb, part_start + part_size - 2, sbi->s_backup_vhdr_buf, (void **)&sbi->s_backup_vhdr, REQ_OP_READ, 0); if (error) goto out_free_backup_vhdr; error = -EINVAL; if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) { pr_warn("invalid secondary volume header\n"); goto out_free_backup_vhdr; } blocksize = be32_to_cpu(sbi->s_vhdr->blocksize); /* * Block size must be at least as large as a sector and a multiple of 2. */ if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize)) goto out_free_backup_vhdr; sbi->alloc_blksz = blocksize; sbi->alloc_blksz_shift = ilog2(blocksize); blocksize = min_t(u32, sbi->alloc_blksz, PAGE_SIZE); /* * Align block size to block offset. */ while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1)) blocksize >>= 1; if (sb_set_blocksize(sb, blocksize) != blocksize) { pr_err("unable to set blocksize to %u!\n", blocksize); goto out_free_backup_vhdr; } sbi->blockoffset = part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT); sbi->part_start = part_start; sbi->sect_count = part_size; sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits; return 0; out_free_backup_vhdr: kfree(sbi->s_backup_vhdr_buf); out_free_vhdr: kfree(sbi->s_vhdr_buf); out: return error; }