298 строки
7.7 KiB
C
298 строки
7.7 KiB
C
/*
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* misc.c
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*
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* PURPOSE
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* Miscellaneous routines for the OSTA-UDF(tm) filesystem.
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*
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* COPYRIGHT
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* This file is distributed under the terms of the GNU General Public
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* License (GPL). Copies of the GPL can be obtained from:
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* ftp://prep.ai.mit.edu/pub/gnu/GPL
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* Each contributing author retains all rights to their own work.
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*
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* (C) 1998 Dave Boynton
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* (C) 1998-2004 Ben Fennema
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* (C) 1999-2000 Stelias Computing Inc
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*
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* HISTORY
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*
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* 04/19/99 blf partial support for reading/writing specific EA's
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*/
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#include "udfdecl.h"
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#include <linux/fs.h>
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#include <linux/string.h>
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#include <linux/udf_fs.h>
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#include <linux/buffer_head.h>
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#include "udf_i.h"
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#include "udf_sb.h"
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struct buffer_head *udf_tgetblk(struct super_block *sb, int block)
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{
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if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
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return sb_getblk(sb, udf_fixed_to_variable(block));
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else
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return sb_getblk(sb, block);
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}
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struct buffer_head *udf_tread(struct super_block *sb, int block)
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{
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if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
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return sb_bread(sb, udf_fixed_to_variable(block));
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else
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return sb_bread(sb, block);
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}
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struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
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uint32_t type, uint8_t loc)
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{
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uint8_t *ea = NULL, *ad = NULL;
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int offset;
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uint16_t crclen;
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struct udf_inode_info *iinfo = UDF_I(inode);
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ea = iinfo->i_ext.i_data;
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if (iinfo->i_lenEAttr) {
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ad = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
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} else {
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ad = ea;
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size += sizeof(struct extendedAttrHeaderDesc);
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}
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offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
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iinfo->i_lenAlloc;
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/* TODO - Check for FreeEASpace */
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if (loc & 0x01 && offset >= size) {
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struct extendedAttrHeaderDesc *eahd;
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eahd = (struct extendedAttrHeaderDesc *)ea;
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if (iinfo->i_lenAlloc)
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memmove(&ad[size], ad, iinfo->i_lenAlloc);
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if (iinfo->i_lenEAttr) {
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/* check checksum/crc */
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if (eahd->descTag.tagIdent !=
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cpu_to_le16(TAG_IDENT_EAHD) ||
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le32_to_cpu(eahd->descTag.tagLocation) !=
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iinfo->i_location.logicalBlockNum)
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return NULL;
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} else {
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struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
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size -= sizeof(struct extendedAttrHeaderDesc);
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iinfo->i_lenEAttr +=
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sizeof(struct extendedAttrHeaderDesc);
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eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
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if (sbi->s_udfrev >= 0x0200)
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eahd->descTag.descVersion = cpu_to_le16(3);
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else
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eahd->descTag.descVersion = cpu_to_le16(2);
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eahd->descTag.tagSerialNum =
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cpu_to_le16(sbi->s_serial_number);
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eahd->descTag.tagLocation = cpu_to_le32(
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iinfo->i_location.logicalBlockNum);
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eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
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eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
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}
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offset = iinfo->i_lenEAttr;
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if (type < 2048) {
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if (le32_to_cpu(eahd->appAttrLocation) <
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iinfo->i_lenEAttr) {
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uint32_t aal =
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le32_to_cpu(eahd->appAttrLocation);
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memmove(&ea[offset - aal + size],
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&ea[aal], offset - aal);
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offset -= aal;
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eahd->appAttrLocation =
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cpu_to_le32(aal + size);
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}
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if (le32_to_cpu(eahd->impAttrLocation) <
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iinfo->i_lenEAttr) {
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uint32_t ial =
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le32_to_cpu(eahd->impAttrLocation);
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memmove(&ea[offset - ial + size],
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&ea[ial], offset - ial);
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offset -= ial;
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eahd->impAttrLocation =
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cpu_to_le32(ial + size);
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}
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} else if (type < 65536) {
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if (le32_to_cpu(eahd->appAttrLocation) <
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iinfo->i_lenEAttr) {
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uint32_t aal =
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le32_to_cpu(eahd->appAttrLocation);
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memmove(&ea[offset - aal + size],
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&ea[aal], offset - aal);
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offset -= aal;
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eahd->appAttrLocation =
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cpu_to_le32(aal + size);
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}
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}
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/* rewrite CRC + checksum of eahd */
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crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
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eahd->descTag.descCRCLength = cpu_to_le16(crclen);
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eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
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sizeof(tag), crclen, 0));
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eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
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iinfo->i_lenEAttr += size;
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return (struct genericFormat *)&ea[offset];
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}
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if (loc & 0x02)
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;
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return NULL;
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}
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struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
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uint8_t subtype)
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{
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struct genericFormat *gaf;
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uint8_t *ea = NULL;
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uint32_t offset;
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struct udf_inode_info *iinfo = UDF_I(inode);
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ea = iinfo->i_ext.i_data;
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if (iinfo->i_lenEAttr) {
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struct extendedAttrHeaderDesc *eahd;
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eahd = (struct extendedAttrHeaderDesc *)ea;
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/* check checksum/crc */
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if (eahd->descTag.tagIdent !=
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cpu_to_le16(TAG_IDENT_EAHD) ||
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le32_to_cpu(eahd->descTag.tagLocation) !=
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iinfo->i_location.logicalBlockNum)
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return NULL;
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if (type < 2048)
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offset = sizeof(struct extendedAttrHeaderDesc);
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else if (type < 65536)
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offset = le32_to_cpu(eahd->impAttrLocation);
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else
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offset = le32_to_cpu(eahd->appAttrLocation);
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while (offset < iinfo->i_lenEAttr) {
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gaf = (struct genericFormat *)&ea[offset];
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if (le32_to_cpu(gaf->attrType) == type &&
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gaf->attrSubtype == subtype)
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return gaf;
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else
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offset += le32_to_cpu(gaf->attrLength);
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}
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}
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return NULL;
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}
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/*
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* udf_read_tagged
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*
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* PURPOSE
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* Read the first block of a tagged descriptor.
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*
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* HISTORY
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* July 1, 1997 - Andrew E. Mileski
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* Written, tested, and released.
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*/
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struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
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uint32_t location, uint16_t *ident)
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{
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tag *tag_p;
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struct buffer_head *bh = NULL;
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struct udf_sb_info *sbi = UDF_SB(sb);
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/* Read the block */
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if (block == 0xFFFFFFFF)
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return NULL;
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bh = udf_tread(sb, block + sbi->s_session);
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if (!bh) {
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udf_debug("block=%d, location=%d: read failed\n",
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block + sbi->s_session, location);
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return NULL;
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}
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tag_p = (tag *)(bh->b_data);
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*ident = le16_to_cpu(tag_p->tagIdent);
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if (location != le32_to_cpu(tag_p->tagLocation)) {
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udf_debug("location mismatch block %u, tag %u != %u\n",
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block + sbi->s_session,
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le32_to_cpu(tag_p->tagLocation), location);
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goto error_out;
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}
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/* Verify the tag checksum */
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if (udf_tag_checksum(tag_p) != tag_p->tagChecksum) {
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printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
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goto error_out;
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}
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/* Verify the tag version */
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if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
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tag_p->descVersion != cpu_to_le16(0x0003U)) {
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udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n",
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le16_to_cpu(tag_p->descVersion), block);
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goto error_out;
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}
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/* Verify the descriptor CRC */
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if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||
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le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
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le16_to_cpu(tag_p->descCRCLength), 0))
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return bh;
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udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
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block + sbi->s_session, le16_to_cpu(tag_p->descCRC),
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le16_to_cpu(tag_p->descCRCLength));
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error_out:
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brelse(bh);
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return NULL;
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}
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struct buffer_head *udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc,
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uint32_t offset, uint16_t *ident)
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{
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return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
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loc.logicalBlockNum + offset, ident);
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}
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void udf_update_tag(char *data, int length)
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{
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tag *tptr = (tag *)data;
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length -= sizeof(tag);
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tptr->descCRCLength = cpu_to_le16(length);
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tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
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tptr->tagChecksum = udf_tag_checksum(tptr);
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}
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void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
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uint32_t loc, int length)
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{
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tag *tptr = (tag *)data;
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tptr->tagIdent = cpu_to_le16(ident);
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tptr->descVersion = cpu_to_le16(version);
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tptr->tagSerialNum = cpu_to_le16(snum);
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tptr->tagLocation = cpu_to_le32(loc);
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udf_update_tag(data, length);
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}
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u8 udf_tag_checksum(const tag *t)
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{
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u8 *data = (u8 *)t;
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u8 checksum = 0;
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int i;
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for (i = 0; i < sizeof(tag); ++i)
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if (i != 4) /* position of checksum */
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checksum += data[i];
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return checksum;
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}
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