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![Fabian Frederick](/assets/img/avatar_default.png)
Replace while blocksize;shift by ilog2 Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
261 lines
6.8 KiB
C
261 lines
6.8 KiB
C
/*
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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 (flar@allandria.com)
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* (C) 2003 Ardis Technologies <roman@ardistech.com>
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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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* @rw: direction of I/O
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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 rw)
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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->bi_bdev = sb->s_bdev;
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if (!(rw & 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(rw, 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_multisession ms_info;
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struct cdrom_tocentry te;
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int res;
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/* default values */
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*start = 0;
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*size = sb->s_bdev->bd_inode->i_size >> 9;
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if (HFSPLUS_SB(sb)->session >= 0) {
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te.cdte_track = HFSPLUS_SB(sb)->session;
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te.cdte_format = CDROM_LBA;
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res = ioctl_by_bdev(sb->s_bdev,
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CDROMREADTOCENTRY, (unsigned long)&te);
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if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
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*start = (sector_t)te.cdte_addr.lba << 2;
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return 0;
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}
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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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ms_info.addr_format = CDROM_LBA;
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res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION,
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(unsigned long)&ms_info);
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if (!res && ms_info.xa_flag)
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*start = (sector_t)ms_info.addr.lba << 2;
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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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READ);
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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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/*FALLTHRU*/
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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, READ);
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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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