[linux-2.6-block.git] / fs / hfsplus / wrapper.c

/*
 *  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;

	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(rw, 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;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/hfsplus/wrapper.c
	3	*
	4	* Copyright (C) 2001
	5	* Brad Boyer (flar@allandria.com)
	6	* (C) 2003 Ardis Technologies <roman@ardistech.com>
	7	*
	8	* Handling of HFS wrappers around HFS+ volumes
	9	*/
	10
	11	#include <linux/fs.h>
	12	#include <linux/blkdev.h>
	13	#include <linux/cdrom.h>
	14	#include <linux/genhd.h>
1da177e4 LT	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
915ab236 FF	27	/**
915ab236 FF	28	* hfsplus_submit_bio - Perform block I/O
6596528e SF	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	* @rw: direction of I/O
	34	*
	35	* The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than
	36	* HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads
	37	* @data will return a pointer to the start of the requested sector,
	38	* which may not be the same location as @buf.
	39	*
	40	* If @sector is not aligned to the bdev logical block size it will
	41	* be rounded down. For writes this means that @buf should contain data
	42	* that starts at the rounded-down address. As long as the data was
	43	* read using hfsplus_submit_bio() and the same buffer is used things
	44	* will work correctly.
	45	*/
	46	int hfsplus_submit_bio(struct super_block *sb, sector_t sector,
	47	void buf, void *data, int rw)
52399b17	48	{
52399b17	49	struct bio *bio;
50176dde	50	int ret = 0;
a6dc8c04	51	u64 io_size;
6596528e SF	52	loff_t start;
	53	int offset;
	54
	55	/*
	56	* Align sector to hardware sector size and find offset. We
	57	* assume that io_size is a power of two, which _should_
	58	* be true.
	59	*/
	60	io_size = hfsplus_min_io_size(sb);
	61	start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT;
	62	offset = start & (io_size - 1);
	63	sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1);
52399b17 CH	64
52399b17 CH	65	bio = bio_alloc(GFP_NOIO, 1);
4f024f37	66	bio->bi_iter.bi_sector = sector;
6596528e	67	bio->bi_bdev = sb->s_bdev;
52399b17	68
6596528e SF	69	if (!(rw & WRITE) && data)
	70	data = (u8 )buf + offset;
	71
	72	while (io_size > 0) {
	73	unsigned int page_offset = offset_in_page(buf);
	74	unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset,
	75	io_size);
	76
	77	ret = bio_add_page(bio, virt_to_page(buf), len, page_offset);
	78	if (ret != len) {
	79	ret = -EIO;
	80	goto out;
	81	}
	82	io_size -= len;
	83	buf = (u8 *)buf + len;
	84	}
52399b17	85
33879d45	86	ret = submit_bio_wait(rw, bio);
6596528e	87	out:
50176dde	88	bio_put(bio);
6596528e	89	return ret < 0 ? ret : 0;
52399b17 CH	90	}
52399b17 CH	91
1da177e4 LT	92	static int hfsplus_read_mdb(void bufptr, struct hfsplus_wd wd)
	93	{
	94	u32 extent;
	95	u16 attrib;
2179d372	96	__be16 sig;
1da177e4	97
2179d372 DE	98	sig = (__be16 )(bufptr + HFSP_WRAPOFF_EMBEDSIG);
	99	if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
	100	sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
1da177e4 LT	101	return 0;
	102
	103	attrib = be16_to_cpu((__be16 )(bufptr + HFSP_WRAPOFF_ATTRIB));
	104	if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) \|\|
	105	!(attrib & HFSP_WRAP_ATTRIB_SPARED))
	106	return 0;
	107
2753cc28 AS	108	wd->ablk_size =
2753cc28 AS	109	be32_to_cpu((__be32 )(bufptr + HFSP_WRAPOFF_ABLKSIZE));
1da177e4 LT	110	if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
	111	return 0;
	112	if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
	113	return 0;
2753cc28 AS	114	wd->ablk_start =
2753cc28 AS	115	be16_to_cpu((__be16 )(bufptr + HFSP_WRAPOFF_ABLKSTART));
1da177e4	116
8b3789e5	117	extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT);
1da177e4 LT	118	wd->embed_start = (extent >> 16) & 0xFFFF;
	119	wd->embed_count = extent & 0xFFFF;
	120
	121	return 1;
	122	}
	123
	124	static int hfsplus_get_last_session(struct super_block *sb,
	125	sector_t start, sector_t size)
	126	{
	127	struct cdrom_multisession ms_info;
	128	struct cdrom_tocentry te;
	129	int res;
	130
	131	/* default values */
	132	*start = 0;
	133	*size = sb->s_bdev->bd_inode->i_size >> 9;
	134
dd73a01a CH	135	if (HFSPLUS_SB(sb)->session >= 0) {
dd73a01a CH	136	te.cdte_track = HFSPLUS_SB(sb)->session;
1da177e4	137	te.cdte_format = CDROM_LBA;
2753cc28 AS	138	res = ioctl_by_bdev(sb->s_bdev,
2753cc28 AS	139	CDROMREADTOCENTRY, (unsigned long)&te);
1da177e4 LT	140	if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
	141	*start = (sector_t)te.cdte_addr.lba << 2;
	142	return 0;
	143	}
d6142673	144	pr_err("invalid session number or type of track\n");
1da177e4 LT	145	return -EINVAL;
	146	}
	147	ms_info.addr_format = CDROM_LBA;
2753cc28 AS	148	res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION,
2753cc28 AS	149	(unsigned long)&ms_info);
1da177e4 LT	150	if (!res && ms_info.xa_flag)
	151	*start = (sector_t)ms_info.addr.lba << 2;
	152	return 0;
	153	}
	154
	155	/* Find the volume header and fill in some minimum bits in superblock */
	156	/* Takes in super block, returns true if good data read */
	157	int hfsplus_read_wrapper(struct super_block *sb)
	158	{
dd73a01a	159	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
1da177e4 LT	160	struct hfsplus_wd wd;
	161	sector_t part_start, part_size;
	162	u32 blocksize;
52399b17	163	int error = 0;
1da177e4	164
52399b17	165	error = -EINVAL;
1da177e4 LT	166	blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
1da177e4 LT	167	if (!blocksize)
52399b17	168	goto out;
1da177e4 LT	169
1da177e4 LT	170	if (hfsplus_get_last_session(sb, &part_start, &part_size))
52399b17	171	goto out;
1da177e4	172
52399b17	173	error = -ENOMEM;
6596528e SF	174	sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
6596528e SF	175	if (!sbi->s_vhdr_buf)
52399b17	176	goto out;
6596528e SF	177	sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
6596528e SF	178	if (!sbi->s_backup_vhdr_buf)
52399b17 CH	179	goto out_free_vhdr;
	180
	181	reread:
6596528e SF	182	error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
	183	sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
	184	READ);
52399b17 CH	185	if (error)
	186	goto out_free_backup_vhdr;
	187
	188	error = -EINVAL;
	189	switch (sbi->s_vhdr->signature) {
	190	case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX):
	191	set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
	192	/FALLTHRU/
	193	case cpu_to_be16(HFSPLUS_VOLHEAD_SIG):
	194	break;
	195	case cpu_to_be16(HFSP_WRAP_MAGIC):
	196	if (!hfsplus_read_mdb(sbi->s_vhdr, &wd))
a1dbcef0	197	goto out_free_backup_vhdr;
52399b17	198	wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
4ba2d5fd CH	199	part_start += (sector_t)wd.ablk_start +
	200	(sector_t)wd.embed_start * wd.ablk_size;
	201	part_size = (sector_t)wd.embed_count * wd.ablk_size;
52399b17 CH	202	goto reread;
	203	default:
	204	/*
	205	* Check for a partition block.
	206	*
1da177e4 LT	207	* (should do this only for cdrom/loop though)
	208	*/
	209	if (hfs_part_find(sb, &part_start, &part_size))
a1dbcef0	210	goto out_free_backup_vhdr;
52399b17 CH	211	goto reread;
	212	}
	213
6596528e SF	214	error = hfsplus_submit_bio(sb, part_start + part_size - 2,
	215	sbi->s_backup_vhdr_buf,
	216	(void **)&sbi->s_backup_vhdr, READ);
52399b17 CH	217	if (error)
	218	goto out_free_backup_vhdr;
	219
	220	error = -EINVAL;
	221	if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) {
d6142673	222	pr_warn("invalid secondary volume header\n");
52399b17	223	goto out_free_backup_vhdr;
1da177e4 LT	224	}
1da177e4 LT	225
52399b17	226	blocksize = be32_to_cpu(sbi->s_vhdr->blocksize);
1da177e4	227
52399b17 CH	228	/*
52399b17 CH	229	* Block size must be at least as large as a sector and a multiple of 2.
1da177e4	230	*/
52399b17 CH	231	if (blocksize < HFSPLUS_SECTOR_SIZE \|\| ((blocksize - 1) & blocksize))
52399b17 CH	232	goto out_free_backup_vhdr;
dd73a01a	233	sbi->alloc_blksz = blocksize;
297cc272	234	sbi->alloc_blksz_shift = ilog2(blocksize);
915ab236	235	blocksize = min_t(u32, sbi->alloc_blksz, PAGE_SIZE);
1da177e4	236
52399b17 CH	237	/*
	238	* Align block size to block offset.
	239	*/
1da177e4 LT	240	while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
	241	blocksize >>= 1;
	242
	243	if (sb_set_blocksize(sb, blocksize) != blocksize) {
d6142673	244	pr_err("unable to set blocksize to %u!\n", blocksize);
52399b17	245	goto out_free_backup_vhdr;
1da177e4 LT	246	}
1da177e4 LT	247
dd73a01a CH	248	sbi->blockoffset =
dd73a01a CH	249	part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
52399b17	250	sbi->part_start = part_start;
dd73a01a CH	251	sbi->sect_count = part_size;
dd73a01a CH	252	sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
1da177e4	253	return 0;
52399b17 CH	254
52399b17 CH	255	out_free_backup_vhdr:
f588c960	256	kfree(sbi->s_backup_vhdr_buf);
52399b17	257	out_free_vhdr:
f588c960	258	kfree(sbi->s_vhdr_buf);
52399b17 CH	259	out:
52399b17 CH	260	return error;
1da177e4	261	}