[linux.git] / fs / hfsplus / wrapper.c

/*
 *  linux/fs/hfsplus/wrapper.c
 *
 * Copyright (C) 2001
 * Brad Boyer ([email protected])
 * (C) 2003 Ardis Technologies <[email protected]>
 *
 * 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;
};

static void hfsplus_end_io_sync(struct bio *bio, int err)
{
	if (err)
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
	complete(bio->bi_private);
}

/*
 * hfsplus_submit_bio - Perfrom 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)
{
	DECLARE_COMPLETION_ONSTACK(wait);
	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_sector = sector;
	bio->bi_bdev = sb->s_bdev;
	bio->bi_end_io = hfsplus_end_io_sync;
	bio->bi_private = &wait;

	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;
	}

	submit_bio(rw, bio);
	wait_for_completion(&wait);

	if (!bio_flagged(bio, BIO_UPTODATE))
		ret = -EIO;

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;
		}
		printk(KERN_ERR "hfs: 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) {
		printk(KERN_WARNING
			"hfs: 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 = 0;
	while ((blocksize >>= 1) != 0)
		sbi->alloc_blksz_shift++;
	blocksize = min(sbi->alloc_blksz, (u32)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) {
		printk(KERN_ERR "hfs: 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 ([email protected])
	6	* (C) 2003 Ardis Technologies <[email protected]>
	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
52399b17 CH	27	static void hfsplus_end_io_sync(struct bio *bio, int err)
	28	{
	29	if (err)
	30	clear_bit(BIO_UPTODATE, &bio->bi_flags);
	31	complete(bio->bi_private);
	32	}
	33
6596528e SF	34	/*
	35	* hfsplus_submit_bio - Perfrom block I/O
	36	* @sb: super block of volume for I/O
	37	* @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes
	38	* @buf: buffer for I/O
	39	* @data: output pointer for location of requested data
	40	* @rw: direction of I/O
	41	*
	42	* The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than
	43	* HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads
	44	* @data will return a pointer to the start of the requested sector,
	45	* which may not be the same location as @buf.
	46	*
	47	* If @sector is not aligned to the bdev logical block size it will
	48	* be rounded down. For writes this means that @buf should contain data
	49	* that starts at the rounded-down address. As long as the data was
	50	* read using hfsplus_submit_bio() and the same buffer is used things
	51	* will work correctly.
	52	*/
	53	int hfsplus_submit_bio(struct super_block *sb, sector_t sector,
	54	void buf, void *data, int rw)
52399b17 CH	55	{
	56	DECLARE_COMPLETION_ONSTACK(wait);
	57	struct bio *bio;
50176dde	58	int ret = 0;
a6dc8c04	59	u64 io_size;
6596528e SF	60	loff_t start;
	61	int offset;
	62
	63	/*
	64	* Align sector to hardware sector size and find offset. We
	65	* assume that io_size is a power of two, which _should_
	66	* be true.
	67	*/
	68	io_size = hfsplus_min_io_size(sb);
	69	start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT;
	70	offset = start & (io_size - 1);
	71	sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1);
52399b17 CH	72
	73	bio = bio_alloc(GFP_NOIO, 1);
	74	bio->bi_sector = sector;
6596528e	75	bio->bi_bdev = sb->s_bdev;
52399b17 CH	76	bio->bi_end_io = hfsplus_end_io_sync;
	77	bio->bi_private = &wait;
	78
6596528e SF	79	if (!(rw & WRITE) && data)
	80	data = (u8 )buf + offset;
	81
	82	while (io_size > 0) {
	83	unsigned int page_offset = offset_in_page(buf);
	84	unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset,
	85	io_size);
	86
	87	ret = bio_add_page(bio, virt_to_page(buf), len, page_offset);
	88	if (ret != len) {
	89	ret = -EIO;
	90	goto out;
	91	}
	92	io_size -= len;
	93	buf = (u8 *)buf + len;
	94	}
52399b17 CH	95
	96	submit_bio(rw, bio);
	97	wait_for_completion(&wait);
	98
	99	if (!bio_flagged(bio, BIO_UPTODATE))
50176dde SF	100	ret = -EIO;
50176dde SF	101
6596528e	102	out:
50176dde	103	bio_put(bio);
6596528e	104	return ret < 0 ? ret : 0;
52399b17 CH	105	}
52399b17 CH	106
1da177e4 LT	107	static int hfsplus_read_mdb(void bufptr, struct hfsplus_wd wd)
	108	{
	109	u32 extent;
	110	u16 attrib;
2179d372	111	__be16 sig;
1da177e4	112
2179d372 DE	113	sig = (__be16 )(bufptr + HFSP_WRAPOFF_EMBEDSIG);
	114	if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
	115	sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
1da177e4 LT	116	return 0;
	117
	118	attrib = be16_to_cpu((__be16 )(bufptr + HFSP_WRAPOFF_ATTRIB));
	119	if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) \|\|
	120	!(attrib & HFSP_WRAP_ATTRIB_SPARED))
	121	return 0;
	122
2753cc28 AS	123	wd->ablk_size =
2753cc28 AS	124	be32_to_cpu((__be32 )(bufptr + HFSP_WRAPOFF_ABLKSIZE));
1da177e4 LT	125	if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
	126	return 0;
	127	if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
	128	return 0;
2753cc28 AS	129	wd->ablk_start =
2753cc28 AS	130	be16_to_cpu((__be16 )(bufptr + HFSP_WRAPOFF_ABLKSTART));
1da177e4	131
8b3789e5	132	extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT);
1da177e4 LT	133	wd->embed_start = (extent >> 16) & 0xFFFF;
	134	wd->embed_count = extent & 0xFFFF;
	135
	136	return 1;
	137	}
	138
	139	static int hfsplus_get_last_session(struct super_block *sb,
	140	sector_t start, sector_t size)
	141	{
	142	struct cdrom_multisession ms_info;
	143	struct cdrom_tocentry te;
	144	int res;
	145
	146	/* default values */
	147	*start = 0;
	148	*size = sb->s_bdev->bd_inode->i_size >> 9;
	149
dd73a01a CH	150	if (HFSPLUS_SB(sb)->session >= 0) {
dd73a01a CH	151	te.cdte_track = HFSPLUS_SB(sb)->session;
1da177e4	152	te.cdte_format = CDROM_LBA;
2753cc28 AS	153	res = ioctl_by_bdev(sb->s_bdev,
2753cc28 AS	154	CDROMREADTOCENTRY, (unsigned long)&te);
1da177e4 LT	155	if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
	156	*start = (sector_t)te.cdte_addr.lba << 2;
	157	return 0;
	158	}
634725a9	159	printk(KERN_ERR "hfs: invalid session number or type of track\n");
1da177e4 LT	160	return -EINVAL;
	161	}
	162	ms_info.addr_format = CDROM_LBA;
2753cc28 AS	163	res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION,
2753cc28 AS	164	(unsigned long)&ms_info);
1da177e4 LT	165	if (!res && ms_info.xa_flag)
	166	*start = (sector_t)ms_info.addr.lba << 2;
	167	return 0;
	168	}
	169
	170	/* Find the volume header and fill in some minimum bits in superblock */
	171	/* Takes in super block, returns true if good data read */
	172	int hfsplus_read_wrapper(struct super_block *sb)
	173	{
dd73a01a	174	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
1da177e4 LT	175	struct hfsplus_wd wd;
	176	sector_t part_start, part_size;
	177	u32 blocksize;
52399b17	178	int error = 0;
1da177e4	179
52399b17	180	error = -EINVAL;
1da177e4 LT	181	blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
1da177e4 LT	182	if (!blocksize)
52399b17	183	goto out;
1da177e4 LT	184
1da177e4 LT	185	if (hfsplus_get_last_session(sb, &part_start, &part_size))
52399b17	186	goto out;
1da177e4	187
52399b17	188	error = -ENOMEM;
6596528e SF	189	sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
6596528e SF	190	if (!sbi->s_vhdr_buf)
52399b17	191	goto out;
6596528e SF	192	sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
6596528e SF	193	if (!sbi->s_backup_vhdr_buf)
52399b17 CH	194	goto out_free_vhdr;
	195
	196	reread:
6596528e SF	197	error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
	198	sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
	199	READ);
52399b17 CH	200	if (error)
	201	goto out_free_backup_vhdr;
	202
	203	error = -EINVAL;
	204	switch (sbi->s_vhdr->signature) {
	205	case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX):
	206	set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
	207	/FALLTHRU/
	208	case cpu_to_be16(HFSPLUS_VOLHEAD_SIG):
	209	break;
	210	case cpu_to_be16(HFSP_WRAP_MAGIC):
	211	if (!hfsplus_read_mdb(sbi->s_vhdr, &wd))
a1dbcef0	212	goto out_free_backup_vhdr;
52399b17	213	wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
4ba2d5fd CH	214	part_start += (sector_t)wd.ablk_start +
	215	(sector_t)wd.embed_start * wd.ablk_size;
	216	part_size = (sector_t)wd.embed_count * wd.ablk_size;
52399b17 CH	217	goto reread;
	218	default:
	219	/*
	220	* Check for a partition block.
	221	*
1da177e4 LT	222	* (should do this only for cdrom/loop though)
	223	*/
	224	if (hfs_part_find(sb, &part_start, &part_size))
a1dbcef0	225	goto out_free_backup_vhdr;
52399b17 CH	226	goto reread;
	227	}
	228
6596528e SF	229	error = hfsplus_submit_bio(sb, part_start + part_size - 2,
	230	sbi->s_backup_vhdr_buf,
	231	(void **)&sbi->s_backup_vhdr, READ);
52399b17 CH	232	if (error)
	233	goto out_free_backup_vhdr;
	234
	235	error = -EINVAL;
	236	if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) {
	237	printk(KERN_WARNING
	238	"hfs: invalid secondary volume header\n");
	239	goto out_free_backup_vhdr;
1da177e4 LT	240	}
1da177e4 LT	241
52399b17	242	blocksize = be32_to_cpu(sbi->s_vhdr->blocksize);
1da177e4	243
52399b17 CH	244	/*
52399b17 CH	245	* Block size must be at least as large as a sector and a multiple of 2.
1da177e4	246	*/
52399b17 CH	247	if (blocksize < HFSPLUS_SECTOR_SIZE \|\| ((blocksize - 1) & blocksize))
52399b17 CH	248	goto out_free_backup_vhdr;
dd73a01a CH	249	sbi->alloc_blksz = blocksize;
dd73a01a CH	250	sbi->alloc_blksz_shift = 0;
1da177e4	251	while ((blocksize >>= 1) != 0)
dd73a01a CH	252	sbi->alloc_blksz_shift++;
dd73a01a CH	253	blocksize = min(sbi->alloc_blksz, (u32)PAGE_SIZE);
1da177e4	254
52399b17 CH	255	/*
	256	* Align block size to block offset.
	257	*/
1da177e4 LT	258	while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
	259	blocksize >>= 1;
	260
	261	if (sb_set_blocksize(sb, blocksize) != blocksize) {
2753cc28 AS	262	printk(KERN_ERR "hfs: unable to set blocksize to %u!\n",
2753cc28 AS	263	blocksize);
52399b17	264	goto out_free_backup_vhdr;
1da177e4 LT	265	}
1da177e4 LT	266
dd73a01a CH	267	sbi->blockoffset =
dd73a01a CH	268	part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
52399b17	269	sbi->part_start = part_start;
dd73a01a CH	270	sbi->sect_count = part_size;
dd73a01a CH	271	sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
1da177e4	272	return 0;
52399b17 CH	273
52399b17 CH	274	out_free_backup_vhdr:
f588c960	275	kfree(sbi->s_backup_vhdr_buf);
52399b17	276	out_free_vhdr:
f588c960	277	kfree(sbi->s_vhdr_buf);
52399b17 CH	278	out:
52399b17 CH	279	return error;
1da177e4	280	}