[mirror_ubuntu-jammy-kernel.git] / fs / udf / misc.c

/*
 * misc.c
 *
 * PURPOSE
 *	Miscellaneous routines for the OSTA-UDF(tm) filesystem.
 *
 * COPYRIGHT
 *	This file is distributed under the terms of the GNU General Public
 *	License (GPL). Copies of the GPL can be obtained from:
 *		ftp://prep.ai.mit.edu/pub/gnu/GPL
 *	Each contributing author retains all rights to their own work.
 *
 *  (C) 1998 Dave Boynton
 *  (C) 1998-2004 Ben Fennema
 *  (C) 1999-2000 Stelias Computing Inc
 *
 * HISTORY
 *
 *  04/19/99 blf  partial support for reading/writing specific EA's
 */

#include "udfdecl.h"

#include <linux/fs.h>
#include <linux/string.h>
#include <linux/udf_fs.h>
#include <linux/buffer_head.h>

#include "udf_i.h"
#include "udf_sb.h"

struct buffer_head *udf_tgetblk(struct super_block *sb, int block)
{
	if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
		return sb_getblk(sb, udf_fixed_to_variable(block));
	else
		return sb_getblk(sb, block);
}

struct buffer_head *udf_tread(struct super_block *sb, int block)
{
	if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
		return sb_bread(sb, udf_fixed_to_variable(block));
	else
		return sb_bread(sb, block);
}

struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
					   uint32_t type, uint8_t loc)
{
	uint8_t *ea = NULL, *ad = NULL;
	int offset;
	uint16_t crclen;
	int i;

	ea = UDF_I_DATA(inode);
	if (UDF_I_LENEATTR(inode)) {
		ad = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode);
	} else {
		ad = ea;
		size += sizeof(struct extendedAttrHeaderDesc);
	}

	offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
		UDF_I_LENALLOC(inode);

	/* TODO - Check for FreeEASpace */

	if (loc & 0x01 && offset >= size) {
		struct extendedAttrHeaderDesc *eahd;
		eahd = (struct extendedAttrHeaderDesc *)ea;

		if (UDF_I_LENALLOC(inode))
			memmove(&ad[size], ad, UDF_I_LENALLOC(inode));

		if (UDF_I_LENEATTR(inode)) {
			/* check checksum/crc */
			if (le16_to_cpu(eahd->descTag.tagIdent) !=
					TAG_IDENT_EAHD ||
			    le32_to_cpu(eahd->descTag.tagLocation) !=
					UDF_I_LOCATION(inode).logicalBlockNum)
				return NULL;
		} else {
			struct udf_sb_info *sbi = UDF_SB(inode->i_sb);

			size -= sizeof(struct extendedAttrHeaderDesc);
			UDF_I_LENEATTR(inode) +=
				sizeof(struct extendedAttrHeaderDesc);
			eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
			if (sbi->s_udfrev >= 0x0200)
				eahd->descTag.descVersion = cpu_to_le16(3);
			else
				eahd->descTag.descVersion = cpu_to_le16(2);
			eahd->descTag.tagSerialNum =
					cpu_to_le16(sbi->s_serial_number);
			eahd->descTag.tagLocation = cpu_to_le32(
					UDF_I_LOCATION(inode).logicalBlockNum);
			eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
			eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
		}

		offset = UDF_I_LENEATTR(inode);
		if (type < 2048) {
			if (le32_to_cpu(eahd->appAttrLocation) <
					UDF_I_LENEATTR(inode)) {
				uint32_t aal =
					le32_to_cpu(eahd->appAttrLocation);
				memmove(&ea[offset - aal + size],
					&ea[aal], offset - aal);
				offset -= aal;
				eahd->appAttrLocation =
						cpu_to_le32(aal + size);
			}
			if (le32_to_cpu(eahd->impAttrLocation) <
					UDF_I_LENEATTR(inode)) {
				uint32_t ial =
					le32_to_cpu(eahd->impAttrLocation);
				memmove(&ea[offset - ial + size],
					&ea[ial], offset - ial);
				offset -= ial;
				eahd->impAttrLocation =
						cpu_to_le32(ial + size);
			}
		} else if (type < 65536) {
			if (le32_to_cpu(eahd->appAttrLocation) <
					UDF_I_LENEATTR(inode)) {
				uint32_t aal =
					le32_to_cpu(eahd->appAttrLocation);
				memmove(&ea[offset - aal + size],
					&ea[aal], offset - aal);
				offset -= aal;
				eahd->appAttrLocation =
						cpu_to_le32(aal + size);
			}
		}
		/* rewrite CRC + checksum of eahd */
		crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
		eahd->descTag.descCRCLength = cpu_to_le16(crclen);
		eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
						sizeof(tag), crclen, 0));
		eahd->descTag.tagChecksum = 0;
		for (i = 0; i < 16; i++)
			if (i != 4)
				eahd->descTag.tagChecksum +=
					((uint8_t *)&(eahd->descTag))[i];
		UDF_I_LENEATTR(inode) += size;
		return (struct genericFormat *)&ea[offset];
	}
	if (loc & 0x02)
		;

	return NULL;
}

struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
					   uint8_t subtype)
{
	struct genericFormat *gaf;
	uint8_t *ea = NULL;
	uint32_t offset;

	ea = UDF_I_DATA(inode);

	if (UDF_I_LENEATTR(inode)) {
		struct extendedAttrHeaderDesc *eahd;
		eahd = (struct extendedAttrHeaderDesc *)ea;

		/* check checksum/crc */
		if (le16_to_cpu(eahd->descTag.tagIdent) !=
				TAG_IDENT_EAHD ||
		    le32_to_cpu(eahd->descTag.tagLocation) !=
				UDF_I_LOCATION(inode).logicalBlockNum)
			return NULL;

		if (type < 2048)
			offset = sizeof(struct extendedAttrHeaderDesc);
		else if (type < 65536)
			offset = le32_to_cpu(eahd->impAttrLocation);
		else
			offset = le32_to_cpu(eahd->appAttrLocation);

		while (offset < UDF_I_LENEATTR(inode)) {
			gaf = (struct genericFormat *)&ea[offset];
			if (le32_to_cpu(gaf->attrType) == type &&
					gaf->attrSubtype == subtype)
				return gaf;
			else
				offset += le32_to_cpu(gaf->attrLength);
		}
	}

	return NULL;
}

/*
 * udf_read_tagged
 *
 * PURPOSE
 *	Read the first block of a tagged descriptor.
 *
 * HISTORY
 *	July 1, 1997 - Andrew E. Mileski
 *	Written, tested, and released.
 */
struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
				    uint32_t location, uint16_t *ident)
{
	tag *tag_p;
	struct buffer_head *bh = NULL;
	register uint8_t checksum;
	register int i;
	struct udf_sb_info *sbi = UDF_SB(sb);

	/* Read the block */
	if (block == 0xFFFFFFFF)
		return NULL;

	bh = udf_tread(sb, block + sbi->s_session);
	if (!bh) {
		udf_debug("block=%d, location=%d: read failed\n",
			  block + sbi->s_session, location);
		return NULL;
	}

	tag_p = (tag *)(bh->b_data);

	*ident = le16_to_cpu(tag_p->tagIdent);

	if (location != le32_to_cpu(tag_p->tagLocation)) {
		udf_debug("location mismatch block %u, tag %u != %u\n",
			  block + sbi->s_session,
			  le32_to_cpu(tag_p->tagLocation), location);
		goto error_out;
	}

	/* Verify the tag checksum */
	checksum = 0U;
	for (i = 0; i < 4; i++)
		checksum += (uint8_t)(bh->b_data[i]);
	for (i = 5; i < 16; i++)
		checksum += (uint8_t)(bh->b_data[i]);
	if (checksum != tag_p->tagChecksum) {
		printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
		goto error_out;
	}

	/* Verify the tag version */
	if (le16_to_cpu(tag_p->descVersion) != 0x0002U &&
	    le16_to_cpu(tag_p->descVersion) != 0x0003U) {
		udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n",
			  le16_to_cpu(tag_p->descVersion), block);
		goto error_out;
	}

	/* Verify the descriptor CRC */
	if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||
	    le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
					le16_to_cpu(tag_p->descCRCLength), 0))
		return bh;

	udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
		  block + sbi->s_session, le16_to_cpu(tag_p->descCRC),
		  le16_to_cpu(tag_p->descCRCLength));

error_out:
	brelse(bh);
	return NULL;
}

struct buffer_head *udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc,
				     uint32_t offset, uint16_t *ident)
{
	return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
			       loc.logicalBlockNum + offset, ident);
}

void udf_update_tag(char *data, int length)
{
	tag *tptr = (tag *)data;
	int i;

	length -= sizeof(tag);

	tptr->tagChecksum = 0;
	tptr->descCRCLength = cpu_to_le16(length);
	tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));

	for (i = 0; i < 16; i++)
		if (i != 4)
			tptr->tagChecksum += (uint8_t)(data[i]);
}

void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
		 uint32_t loc, int length)
{
	tag *tptr = (tag *)data;
	tptr->tagIdent = cpu_to_le16(ident);
	tptr->descVersion = cpu_to_le16(version);
	tptr->tagSerialNum = cpu_to_le16(snum);
	tptr->tagLocation = cpu_to_le32(loc);
	udf_update_tag(data, length);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* misc.c
	3	*
	4	* PURPOSE
	5	* Miscellaneous routines for the OSTA-UDF(tm) filesystem.
	6	*
1da177e4 LT	7	* COPYRIGHT
	8	* This file is distributed under the terms of the GNU General Public
	9	* License (GPL). Copies of the GPL can be obtained from:
	10	* ftp://prep.ai.mit.edu/pub/gnu/GPL
	11	* Each contributing author retains all rights to their own work.
	12	*
	13	* (C) 1998 Dave Boynton
	14	* (C) 1998-2004 Ben Fennema
	15	* (C) 1999-2000 Stelias Computing Inc
	16	*
	17	* HISTORY
	18	*
	19	* 04/19/99 blf partial support for reading/writing specific EA's
	20	*/
	21
	22	#include "udfdecl.h"
	23
	24	#include <linux/fs.h>
	25	#include <linux/string.h>
	26	#include <linux/udf_fs.h>
	27	#include <linux/buffer_head.h>
	28
	29	#include "udf_i.h"
	30	#include "udf_sb.h"
	31
cb00ea35	32	struct buffer_head udf_tgetblk(struct super_block sb, int block)
1da177e4 LT	33	{
	34	if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
	35	return sb_getblk(sb, udf_fixed_to_variable(block));
	36	else
	37	return sb_getblk(sb, block);
	38	}
	39
cb00ea35	40	struct buffer_head udf_tread(struct super_block sb, int block)
1da177e4 LT	41	{
	42	if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
	43	return sb_bread(sb, udf_fixed_to_variable(block));
	44	else
	45	return sb_bread(sb, block);
	46	}
	47
cb00ea35 CG	48	struct genericFormat udf_add_extendedattr(struct inode inode, uint32_t size,
cb00ea35 CG	49	uint32_t type, uint8_t loc)
1da177e4 LT	50	{
	51	uint8_t ea = NULL, ad = NULL;
	52	int offset;
	53	uint16_t crclen;
	54	int i;
	55
	56	ea = UDF_I_DATA(inode);
28de7948	57	if (UDF_I_LENEATTR(inode)) {
1da177e4	58	ad = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode);
28de7948	59	} else {
1da177e4 LT	60	ad = ea;
	61	size += sizeof(struct extendedAttrHeaderDesc);
	62	}
	63
	64	offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
28de7948	65	UDF_I_LENALLOC(inode);
1da177e4 LT	66
	67	/* TODO - Check for FreeEASpace */
	68
cb00ea35	69	if (loc & 0x01 && offset >= size) {
1da177e4 LT	70	struct extendedAttrHeaderDesc *eahd;
	71	eahd = (struct extendedAttrHeaderDesc *)ea;
	72
4b11111a	73	if (UDF_I_LENALLOC(inode))
1da177e4	74	memmove(&ad[size], ad, UDF_I_LENALLOC(inode));
1da177e4	75
cb00ea35	76	if (UDF_I_LENEATTR(inode)) {
1da177e4	77	/* check checksum/crc */
4b11111a MS	78	if (le16_to_cpu(eahd->descTag.tagIdent) !=
	79	TAG_IDENT_EAHD \|\|
	80	le32_to_cpu(eahd->descTag.tagLocation) !=
	81	UDF_I_LOCATION(inode).logicalBlockNum)
1da177e4	82	return NULL;
cb00ea35	83	} else {
6c79e987 MS	84	struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
6c79e987 MS	85
1da177e4	86	size -= sizeof(struct extendedAttrHeaderDesc);
4b11111a MS	87	UDF_I_LENEATTR(inode) +=
4b11111a MS	88	sizeof(struct extendedAttrHeaderDesc);
1da177e4	89	eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
6c79e987	90	if (sbi->s_udfrev >= 0x0200)
1da177e4 LT	91	eahd->descTag.descVersion = cpu_to_le16(3);
	92	else
	93	eahd->descTag.descVersion = cpu_to_le16(2);
4b11111a MS	94	eahd->descTag.tagSerialNum =
	95	cpu_to_le16(sbi->s_serial_number);
	96	eahd->descTag.tagLocation = cpu_to_le32(
	97	UDF_I_LOCATION(inode).logicalBlockNum);
1da177e4 LT	98	eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
	99	eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
	100	}
	101
	102	offset = UDF_I_LENEATTR(inode);
cb00ea35	103	if (type < 2048) {
4b11111a MS	104	if (le32_to_cpu(eahd->appAttrLocation) <
	105	UDF_I_LENEATTR(inode)) {
	106	uint32_t aal =
	107	le32_to_cpu(eahd->appAttrLocation);
28de7948 CG	108	memmove(&ea[offset - aal + size],
28de7948 CG	109	&ea[aal], offset - aal);
1da177e4	110	offset -= aal;
4b11111a MS	111	eahd->appAttrLocation =
4b11111a MS	112	cpu_to_le32(aal + size);
1da177e4	113	}
4b11111a MS	114	if (le32_to_cpu(eahd->impAttrLocation) <
	115	UDF_I_LENEATTR(inode)) {
	116	uint32_t ial =
	117	le32_to_cpu(eahd->impAttrLocation);
28de7948 CG	118	memmove(&ea[offset - ial + size],
28de7948 CG	119	&ea[ial], offset - ial);
1da177e4	120	offset -= ial;
4b11111a MS	121	eahd->impAttrLocation =
4b11111a MS	122	cpu_to_le32(ial + size);
1da177e4	123	}
cb00ea35	124	} else if (type < 65536) {
4b11111a MS	125	if (le32_to_cpu(eahd->appAttrLocation) <
	126	UDF_I_LENEATTR(inode)) {
	127	uint32_t aal =
	128	le32_to_cpu(eahd->appAttrLocation);
28de7948 CG	129	memmove(&ea[offset - aal + size],
28de7948 CG	130	&ea[aal], offset - aal);
1da177e4	131	offset -= aal;
4b11111a MS	132	eahd->appAttrLocation =
4b11111a MS	133	cpu_to_le32(aal + size);
1da177e4 LT	134	}
	135	}
	136	/* rewrite CRC + checksum of eahd */
	137	crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
	138	eahd->descTag.descCRCLength = cpu_to_le16(crclen);
28de7948	139	eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
4b11111a	140	sizeof(tag), crclen, 0));
1da177e4	141	eahd->descTag.tagChecksum = 0;
cb00ea35	142	for (i = 0; i < 16; i++)
1da177e4	143	if (i != 4)
4b11111a MS	144	eahd->descTag.tagChecksum +=
4b11111a MS	145	((uint8_t *)&(eahd->descTag))[i];
1da177e4 LT	146	UDF_I_LENEATTR(inode) += size;
	147	return (struct genericFormat *)&ea[offset];
	148	}
4b11111a MS	149	if (loc & 0x02)
4b11111a MS	150	;
28de7948	151
1da177e4 LT	152	return NULL;
	153	}
	154
cb00ea35 CG	155	struct genericFormat udf_get_extendedattr(struct inode inode, uint32_t type,
cb00ea35 CG	156	uint8_t subtype)
1da177e4 LT	157	{
	158	struct genericFormat *gaf;
	159	uint8_t *ea = NULL;
	160	uint32_t offset;
	161
	162	ea = UDF_I_DATA(inode);
	163
cb00ea35	164	if (UDF_I_LENEATTR(inode)) {
1da177e4 LT	165	struct extendedAttrHeaderDesc *eahd;
	166	eahd = (struct extendedAttrHeaderDesc *)ea;
	167
	168	/* check checksum/crc */
4b11111a MS	169	if (le16_to_cpu(eahd->descTag.tagIdent) !=
	170	TAG_IDENT_EAHD \|\|
	171	le32_to_cpu(eahd->descTag.tagLocation) !=
	172	UDF_I_LOCATION(inode).logicalBlockNum)
1da177e4	173	return NULL;
cb00ea35	174
1da177e4 LT	175	if (type < 2048)
	176	offset = sizeof(struct extendedAttrHeaderDesc);
	177	else if (type < 65536)
	178	offset = le32_to_cpu(eahd->impAttrLocation);
	179	else
	180	offset = le32_to_cpu(eahd->appAttrLocation);
	181
cb00ea35	182	while (offset < UDF_I_LENEATTR(inode)) {
1da177e4	183	gaf = (struct genericFormat *)&ea[offset];
4b11111a MS	184	if (le32_to_cpu(gaf->attrType) == type &&
4b11111a MS	185	gaf->attrSubtype == subtype)
1da177e4 LT	186	return gaf;
	187	else
	188	offset += le32_to_cpu(gaf->attrLength);
	189	}
	190	}
28de7948	191
1da177e4 LT	192	return NULL;
	193	}
	194
	195	/*
	196	* udf_read_tagged
	197	*
	198	* PURPOSE
	199	* Read the first block of a tagged descriptor.
	200	*
	201	* HISTORY
	202	* July 1, 1997 - Andrew E. Mileski
	203	* Written, tested, and released.
	204	*/
cb00ea35	205	struct buffer_head udf_read_tagged(struct super_block sb, uint32_t block,
4b11111a	206	uint32_t location, uint16_t *ident)
1da177e4 LT	207	{
	208	tag *tag_p;
	209	struct buffer_head *bh = NULL;
	210	register uint8_t checksum;
	211	register int i;
6c79e987	212	struct udf_sb_info *sbi = UDF_SB(sb);
1da177e4 LT	213
	214	/* Read the block */
	215	if (block == 0xFFFFFFFF)
	216	return NULL;
	217
6c79e987	218	bh = udf_tread(sb, block + sbi->s_session);
cb00ea35 CG	219	if (!bh) {
cb00ea35 CG	220	udf_debug("block=%d, location=%d: read failed\n",
6c79e987	221	block + sbi->s_session, location);
1da177e4 LT	222	return NULL;
	223	}
	224
28de7948	225	tag_p = (tag *)(bh->b_data);
1da177e4 LT	226
	227	*ident = le16_to_cpu(tag_p->tagIdent);
	228
cb00ea35	229	if (location != le32_to_cpu(tag_p->tagLocation)) {
1da177e4	230	udf_debug("location mismatch block %u, tag %u != %u\n",
4b11111a MS	231	block + sbi->s_session,
4b11111a MS	232	le32_to_cpu(tag_p->tagLocation), location);
1da177e4 LT	233	goto error_out;
1da177e4 LT	234	}
cb00ea35	235
1da177e4 LT	236	/* Verify the tag checksum */
	237	checksum = 0U;
	238	for (i = 0; i < 4; i++)
28de7948	239	checksum += (uint8_t)(bh->b_data[i]);
1da177e4	240	for (i = 5; i < 16; i++)
28de7948	241	checksum += (uint8_t)(bh->b_data[i]);
1da177e4 LT	242	if (checksum != tag_p->tagChecksum) {
	243	printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
	244	goto error_out;
	245	}
	246
	247	/* Verify the tag version */
	248	if (le16_to_cpu(tag_p->descVersion) != 0x0002U &&
cb00ea35	249	le16_to_cpu(tag_p->descVersion) != 0x0003U) {
1da177e4	250	udf_debug("tag version 0x%04x != 0x0002 \|\| 0x0003 block %d\n",
cb00ea35	251	le16_to_cpu(tag_p->descVersion), block);
1da177e4 LT	252	goto error_out;
	253	}
	254
	255	/* Verify the descriptor CRC */
	256	if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize \|\|
cb00ea35	257	le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
4b11111a	258	le16_to_cpu(tag_p->descCRCLength), 0))
1da177e4	259	return bh;
4b11111a	260
1da177e4	261	udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
6c79e987	262	block + sbi->s_session, le16_to_cpu(tag_p->descCRC),
cb00ea35	263	le16_to_cpu(tag_p->descCRCLength));
1da177e4	264
28de7948	265	error_out:
1da177e4 LT	266	brelse(bh);
	267	return NULL;
	268	}
	269
cb00ea35	270	struct buffer_head udf_read_ptagged(struct super_block sb, kernel_lb_addr loc,
4b11111a	271	uint32_t offset, uint16_t *ident)
1da177e4 LT	272	{
1da177e4 LT	273	return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
cb00ea35	274	loc.logicalBlockNum + offset, ident);
1da177e4 LT	275	}
1da177e4 LT	276
1da177e4 LT	277	void udf_update_tag(char *data, int length)
1da177e4 LT	278	{
28de7948	279	tag tptr = (tag )data;
1da177e4 LT	280	int i;
	281
	282	length -= sizeof(tag);
	283
	284	tptr->tagChecksum = 0;
	285	tptr->descCRCLength = cpu_to_le16(length);
	286	tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
	287
cb00ea35	288	for (i = 0; i < 16; i++)
1da177e4	289	if (i != 4)
28de7948	290	tptr->tagChecksum += (uint8_t)(data[i]);
1da177e4 LT	291	}
	292
	293	void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
cb00ea35	294	uint32_t loc, int length)
1da177e4	295	{
28de7948	296	tag tptr = (tag )data;
1da177e4 LT	297	tptr->tagIdent = cpu_to_le16(ident);
	298	tptr->descVersion = cpu_to_le16(version);
	299	tptr->tagSerialNum = cpu_to_le16(snum);
	300	tptr->tagLocation = cpu_to_le32(loc);
	301	udf_update_tag(data, length);
	302	}