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/*
* 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
* @rw: direction of I/O
*
* 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 rw)
{
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->bi_bdev = sb->s_bdev;
bio->bi_rw = rw;
if (!(rw & 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 = sb->s_bdev->bd_inode->i_size >> 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,
READ);
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, READ);
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;
}
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