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