[net-next-2.6.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;
};

static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd)
{
	u32 extent;
	u16 attrib;

	if (be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG)) != HFSPLUS_VOLHEAD_SIG)
		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 = be32_to_cpu(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 buffer_head *bh;
	struct hfsplus_vh *vhdr;
	struct hfsplus_wd wd;
	sector_t part_start, part_size;
	u32 blocksize;

	blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
	if (!blocksize)
		return -EINVAL;

	if (hfsplus_get_last_session(sb, &part_start, &part_size))
		return -EINVAL;
	while (1) {
		bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
		if (!bh)
			return -EIO;

		if (vhdr->signature == cpu_to_be16(HFSP_WRAP_MAGIC)) {
			if (!hfsplus_read_mdb(vhdr, &wd))
				goto error;
			wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
			part_start += wd.ablk_start + wd.embed_start * wd.ablk_size;
			part_size = wd.embed_count * wd.ablk_size;
			brelse(bh);
			bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
			if (!bh)
				return -EIO;
		}
		if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIG))
			break;
		brelse(bh);

		/* check for a partition block
		 * (should do this only for cdrom/loop though)
		 */
		if (hfs_part_find(sb, &part_start, &part_size))
			return -EINVAL;
	}

	blocksize = be32_to_cpu(vhdr->blocksize);
	brelse(bh);

	/* block size must be at least as large as a sector
	 * and a multiple of 2
	 */
	if (blocksize < HFSPLUS_SECTOR_SIZE ||
	    ((blocksize - 1) & blocksize))
		return -EINVAL;
	HFSPLUS_SB(sb).alloc_blksz = blocksize;
	HFSPLUS_SB(sb).alloc_blksz_shift = 0;
	while ((blocksize >>= 1) != 0)
		HFSPLUS_SB(sb).alloc_blksz_shift++;
	blocksize = min(HFSPLUS_SB(sb).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("HFS+: unable to blocksize to %u!\n", blocksize);
		return -EINVAL;
	}

	HFSPLUS_SB(sb).blockoffset = part_start >>
			(sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
	HFSPLUS_SB(sb).sect_count = part_size;
	HFSPLUS_SB(sb).fs_shift = HFSPLUS_SB(sb).alloc_blksz_shift -
			sb->s_blocksize_bits;

	bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
	if (!bh)
		return -EIO;

	/* should still be the same... */
	if (be16_to_cpu(vhdr->signature) != HFSPLUS_VOLHEAD_SIG)
		goto error;
	HFSPLUS_SB(sb).s_vhbh = bh;
	HFSPLUS_SB(sb).s_vhdr = vhdr;

	return 0;
 error:
	brelse(bh);
	return -EINVAL;
}
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
	27	static int hfsplus_read_mdb(void bufptr, struct hfsplus_wd wd)
	28	{
	29	u32 extent;
	30	u16 attrib;
	31
	32	if (be16_to_cpu((__be16 )(bufptr + HFSP_WRAPOFF_EMBEDSIG)) != HFSPLUS_VOLHEAD_SIG)
	33	return 0;
	34
	35	attrib = be16_to_cpu((__be16 )(bufptr + HFSP_WRAPOFF_ATTRIB));
	36	if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) \|\|
	37	!(attrib & HFSP_WRAP_ATTRIB_SPARED))
	38	return 0;
	39
	40	wd->ablk_size = be32_to_cpu((__be32 )(bufptr + HFSP_WRAPOFF_ABLKSIZE));
	41	if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
	42	return 0;
	43	if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
	44	return 0;
	45	wd->ablk_start = be16_to_cpu((__be16 )(bufptr + HFSP_WRAPOFF_ABLKSTART));
	46
	47	extent = be32_to_cpu(get_unaligned((__be32 *)(bufptr + HFSP_WRAPOFF_EMBEDEXT)));
	48	wd->embed_start = (extent >> 16) & 0xFFFF;
	49	wd->embed_count = extent & 0xFFFF;
	50
	51	return 1;
	52	}
	53
	54	static int hfsplus_get_last_session(struct super_block *sb,
	55	sector_t start, sector_t size)
	56	{
	57	struct cdrom_multisession ms_info;
	58	struct cdrom_tocentry te;
	59	int res;
	60
	61	/* default values */
	62	*start = 0;
	63	*size = sb->s_bdev->bd_inode->i_size >> 9;
	64
	65	if (HFSPLUS_SB(sb).session >= 0) {
	66	te.cdte_track = HFSPLUS_SB(sb).session;
	67	te.cdte_format = CDROM_LBA;
	68	res = ioctl_by_bdev(sb->s_bdev, CDROMREADTOCENTRY, (unsigned long)&te);
	69	if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
	70	*start = (sector_t)te.cdte_addr.lba << 2;
	71	return 0;
	72	}
	73	printk(KERN_ERR "HFS: Invalid session number or type of track\n");
	74	return -EINVAL;
	75	}
	76	ms_info.addr_format = CDROM_LBA;
	77	res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, (unsigned long)&ms_info);
	78	if (!res && ms_info.xa_flag)
79	*start = (sector_t)ms_info.addr.lba << 2;
80	return 0;
81	}
82
83	/* Find the volume header and fill in some minimum bits in superblock */
84	/* Takes in super block, returns true if good data read */
85	int hfsplus_read_wrapper(struct super_block *sb)
86	{
87	struct buffer_head *bh;
88	struct hfsplus_vh *vhdr;
89	struct hfsplus_wd wd;
90	sector_t part_start, part_size;
91	u32 blocksize;
92
93	blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
94	if (!blocksize)
95	return -EINVAL;
96
97	if (hfsplus_get_last_session(sb, &part_start, &part_size))
98	return -EINVAL;
99	while (1) {
100	bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
101	if (!bh)
102	return -EIO;
103
104	if (vhdr->signature == cpu_to_be16(HFSP_WRAP_MAGIC)) {
105	if (!hfsplus_read_mdb(vhdr, &wd))
106	goto error;
107	wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
108	part_start += wd.ablk_start + wd.embed_start * wd.ablk_size;
109	part_size = wd.embed_count * wd.ablk_size;
110	brelse(bh);
111	bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
112	if (!bh)
113	return -EIO;
114	}
115	if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIG))
116	break;
117	brelse(bh);
118
119	/* check for a partition block
120	* (should do this only for cdrom/loop though)
121	*/
122	if (hfs_part_find(sb, &part_start, &part_size))
123	return -EINVAL;
124	}
125
126	blocksize = be32_to_cpu(vhdr->blocksize);
127	brelse(bh);
128
129	/* block size must be at least as large as a sector
130	* and a multiple of 2
131	*/
132	if (blocksize < HFSPLUS_SECTOR_SIZE \|\|
133	((blocksize - 1) & blocksize))
134	return -EINVAL;
135	HFSPLUS_SB(sb).alloc_blksz = blocksize;
136	HFSPLUS_SB(sb).alloc_blksz_shift = 0;
137	while ((blocksize >>= 1) != 0)
138	HFSPLUS_SB(sb).alloc_blksz_shift++;
139	blocksize = min(HFSPLUS_SB(sb).alloc_blksz, (u32)PAGE_SIZE);
140
141	/* align block size to block offset */
142	while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
143	blocksize >>= 1;
144
145	if (sb_set_blocksize(sb, blocksize) != blocksize) {
146	printk("HFS+: unable to blocksize to %u!\n", blocksize);
147	return -EINVAL;
148	}
149
150	HFSPLUS_SB(sb).blockoffset = part_start >>
151	(sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
152	HFSPLUS_SB(sb).sect_count = part_size;
153	HFSPLUS_SB(sb).fs_shift = HFSPLUS_SB(sb).alloc_blksz_shift -
154	sb->s_blocksize_bits;
155
156	bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
157	if (!bh)
158	return -EIO;
159
160	/* should still be the same... */
161	if (be16_to_cpu(vhdr->signature) != HFSPLUS_VOLHEAD_SIG)
162	goto error;
163	HFSPLUS_SB(sb).s_vhbh = bh;
164	HFSPLUS_SB(sb).s_vhdr = vhdr;
165
166	return 0;
167	error:
168	brelse(bh);
169	return -EINVAL;
170	}