super.c

这是Linux系统下的对UDF文件系统新增的功能

 *	Note that the Linux kernel can currently only deal with blocksizes of
 *	512, 1024, 2048, 4096, and 8192 bytes.
 *
 * PRE-CONDITIONS
 *	sb			Pointer to _locked_ superblock.
 *
 * POST-CONDITIONS
 *	sb->s_blocksize		Blocksize.
 *	sb->s_blocksize_bits	log2 of blocksize.
 *	<return>	0	Blocksize is valid.
 *	<return>	1	Blocksize is invalid.
 *
 * HISTORY
 *	July 1, 1997 - Andrew E. Mileski
 *	Written, tested, and released.
 */
static  int
udf_set_blocksize(struct super_block *sb, int bsize)
{
	if (!sb_min_blocksize(sb, bsize)) {
		udf_debug("Bad block size (%d)\n", bsize);
		printk(KERN_ERR "udf: bad block size (%d)\n", bsize);
		return 0;
	}
	return sb->s_blocksize;
}

static int
udf_vrs(struct super_block *sb, int silent)
{
	struct volStructDesc *vsd = NULL;
	int sector = 32768;
	int sectorsize;
	struct buffer_head *bh = NULL;
	int iso9660=0;
	int nsr02=0;
	int nsr03=0;

	/* Block size must be a multiple of 512 */
	if (sb->s_blocksize & 511)
		return 0;

	if (sb->s_blocksize < sizeof(struct volStructDesc))
		sectorsize = sizeof(struct volStructDesc);
	else
		sectorsize = sb->s_blocksize;

	sector += (UDF_SB_SESSION(sb) << sb->s_blocksize_bits);

	udf_debug("Starting at sector %u (%ld byte sectors)\n",
		(sector >> sb->s_blocksize_bits), sb->s_blocksize);
	/* Process the sequence (if applicable) */
	for (;!nsr02 && !nsr03; sector += sectorsize)
	{
		/* Read a block */
		bh = udf_tread(sb, sector >> sb->s_blocksize_bits);
		if (!bh)
			break;

		/* Look for ISO  descriptors */
		vsd = (struct volStructDesc *)(bh->b_data +
			(sector & (sb->s_blocksize - 1)));

		if (vsd->stdIdent[0] == 0)
		{
			udf_release_data(bh);
			break;
		}
		else if (!strncmp(vsd->stdIdent, VSD_STD_ID_CD001, VSD_STD_ID_LEN))
		{
			iso9660 = sector;
			switch (vsd->structType)
			{
				case 0: 
					udf_debug("ISO9660 Boot Record found\n");
					break;
				case 1: 
					udf_debug("ISO9660 Primary Volume Descriptor found\n");
					break;
				case 2: 
					udf_debug("ISO9660 Supplementary Volume Descriptor found\n");
					break;
				case 3: 
					udf_debug("ISO9660 Volume Partition Descriptor found\n");
					break;
				case 255: 
					udf_debug("ISO9660 Volume Descriptor Set Terminator found\n");
					break;
				default: 
					udf_debug("ISO9660 VRS (%u) found\n", vsd->structType);
					break;
			}
		}
		else if (!strncmp(vsd->stdIdent, VSD_STD_ID_BEA01, VSD_STD_ID_LEN))
		{
		}
		else if (!strncmp(vsd->stdIdent, VSD_STD_ID_TEA01, VSD_STD_ID_LEN))
		{
			udf_release_data(bh);
			break;
		}
		else if (!strncmp(vsd->stdIdent, VSD_STD_ID_NSR02, VSD_STD_ID_LEN))
		{
			nsr02 = sector;
		}
		else if (!strncmp(vsd->stdIdent, VSD_STD_ID_NSR03, VSD_STD_ID_LEN))
		{
			nsr03 = sector;
		}
		udf_release_data(bh);
	}

	if (nsr03)
		return nsr03;
	else if (nsr02)
		return nsr02;
	else if (sector - (UDF_SB_SESSION(sb) << sb->s_blocksize_bits) == 32768)
		return -1;
	else
		return 0;
}

/*
 * udf_find_anchor
 *
 * PURPOSE
 *	Find an anchor volume descriptor.
 *
 * PRE-CONDITIONS
 *	sb			Pointer to _locked_ superblock.
 *	lastblock		Last block on media.
 *
 * POST-CONDITIONS
 *	<return>		1 if not found, 0 if ok
 *
 * HISTORY
 *	July 1, 1997 - Andrew E. Mileski
 *	Written, tested, and released.
 */
static void
udf_find_anchor(struct super_block *sb)
{
	int lastblock = UDF_SB_LASTBLOCK(sb);
	struct buffer_head *bh = NULL;
	uint16_t ident;
	uint32_t location;
	int i;

	if (lastblock)
	{
		int varlastblock = udf_variable_to_fixed(lastblock);
		int last[] =  { lastblock, lastblock - 2,
				lastblock - 150, lastblock - 152,
				varlastblock, varlastblock - 2,
				varlastblock - 150, varlastblock - 152 };

		lastblock = 0;

		/* Search for an anchor volume descriptor pointer */

		/*  according to spec, anchor is in either:
		 *     block 256
		 *     lastblock-256
		 *     lastblock
		 *  however, if the disc isn't closed, it could be 512 */

		for (i=0; (!lastblock && i<sizeof(last)/sizeof(int)); i++)
		{
			if (last[i] < 0 || !(bh = sb_bread(sb, last[i])))
			{
				ident = location = 0;
			}
			else
			{
				ident = le16_to_cpu(((tag *)bh->b_data)->tagIdent);
				location = le32_to_cpu(((tag *)bh->b_data)->tagLocation);
				udf_release_data(bh);
			}
	
			if (ident == TAG_IDENT_AVDP)
			{
				if (location == last[i] - UDF_SB_SESSION(sb))
				{
					lastblock = UDF_SB_ANCHOR(sb)[0] = last[i] - UDF_SB_SESSION(sb);
					UDF_SB_ANCHOR(sb)[1] = last[i] - 256 - UDF_SB_SESSION(sb);
				}
				else if (location == udf_variable_to_fixed(last[i]) - UDF_SB_SESSION(sb))
				{
					UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
					lastblock = UDF_SB_ANCHOR(sb)[0] = udf_variable_to_fixed(last[i]) - UDF_SB_SESSION(sb);
					UDF_SB_ANCHOR(sb)[1] = lastblock - 256 - UDF_SB_SESSION(sb);
				}
				else
					udf_debug("Anchor found at block %d, location mismatch %d.\n",
						last[i], location);
			}
			else if (ident == TAG_IDENT_FE || ident == TAG_IDENT_EFE)
			{
				lastblock = last[i];
				UDF_SB_ANCHOR(sb)[3] = 512;
			}
			else
			{
				if (last[i] < 256 || !(bh = sb_bread(sb, last[i] - 256)))
				{
					ident = location = 0;
				}
				else
				{
					ident = le16_to_cpu(((tag *)bh->b_data)->tagIdent);
					location = le32_to_cpu(((tag *)bh->b_data)->tagLocation);
					udf_release_data(bh);
				}
	
				if (ident == TAG_IDENT_AVDP &&
					location == last[i] - 256 - UDF_SB_SESSION(sb))
				{
					lastblock = last[i];
					UDF_SB_ANCHOR(sb)[1] = last[i] - 256;
				}
				else
				{
					if (last[i] < 312 + UDF_SB_SESSION(sb) || !(bh = sb_bread(sb, last[i] - 312 - UDF_SB_SESSION(sb))))
					{
						ident = location = 0;
					}
					else
					{
						ident = le16_to_cpu(((tag *)bh->b_data)->tagIdent);
						location = le32_to_cpu(((tag *)bh->b_data)->tagLocation);
						udf_release_data(bh);
					}
	
					if (ident == TAG_IDENT_AVDP &&
						location == udf_variable_to_fixed(last[i]) - 256)
					{
						UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
						lastblock = udf_variable_to_fixed(last[i]);
						UDF_SB_ANCHOR(sb)[1] = lastblock - 256;
					}
				}
			}
		}
	}

	if (!lastblock)
	{
		/* We havn't found the lastblock. check 312 */
		if ((bh = sb_bread(sb, 312 + UDF_SB_SESSION(sb))))
		{
			ident = le16_to_cpu(((tag *)bh->b_data)->tagIdent);
			location = le32_to_cpu(((tag *)bh->b_data)->tagLocation);
			udf_release_data(bh);

			if (ident == TAG_IDENT_AVDP && location == 256)
				UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
		}
	}

	for (i=0; i<sizeof(UDF_SB_ANCHOR(sb))/sizeof(int); i++)
	{
		if (UDF_SB_ANCHOR(sb)[i])
		{
			if (!(bh = udf_read_tagged(sb,
				UDF_SB_ANCHOR(sb)[i], UDF_SB_ANCHOR(sb)[i], &ident)))
			{
				UDF_SB_ANCHOR(sb)[i] = 0;
			}
			else
			{
				udf_release_data(bh);
				if ((ident != TAG_IDENT_AVDP) && (i ||
					(ident != TAG_IDENT_FE && ident != TAG_IDENT_EFE)))
				{
					UDF_SB_ANCHOR(sb)[i] = 0;
				}
			}
		}
	}

	UDF_SB_LASTBLOCK(sb) = lastblock;
}

static int 
udf_find_fileset(struct super_block *sb, lb_addr *fileset, lb_addr *root)
{
	struct buffer_head *bh = NULL;
	long lastblock;
	uint16_t ident;

	if (fileset->logicalBlockNum != 0xFFFFFFFF ||
		fileset->partitionReferenceNum != 0xFFFF)
	{
		bh = udf_read_ptagged(sb, *fileset, 0, &ident);

		if (!bh)
			return 1;
		else if (ident != TAG_IDENT_FSD)
		{
			udf_release_data(bh);
			return 1;
		}
			
	}

	if (!bh) /* Search backwards through the partitions */
	{
		lb_addr newfileset;

		return 1;
		
		for (newfileset.partitionReferenceNum=UDF_SB_NUMPARTS(sb)-1;
			(newfileset.partitionReferenceNum != 0xFFFF &&
				fileset->logicalBlockNum == 0xFFFFFFFF &&
				fileset->partitionReferenceNum == 0xFFFF);
			newfileset.partitionReferenceNum--)
		{
			lastblock = UDF_SB_PARTLEN(sb, newfileset.partitionReferenceNum);
			newfileset.logicalBlockNum = 0;

			do
			{
				bh = udf_read_ptagged(sb, newfileset, 0, &ident);
				if (!bh)
				{
					newfileset.logicalBlockNum ++;
					continue;
				}

				switch (ident)
				{
					case TAG_IDENT_SBD:
					{
						struct spaceBitmapDesc *sp;
						sp = (struct spaceBitmapDesc *)bh->b_data;
						newfileset.logicalBlockNum += 1 +
							((le32_to_cpu(sp->numOfBytes) + sizeof(struct spaceBitmapDesc) - 1)
								>> sb->s_blocksize_bits);
						udf_release_data(bh);
						break;
					}
					case TAG_IDENT_FSD:
					{
						*fileset = newfileset;
						break;
					}
					default:
					{
						newfileset.logicalBlockNum ++;
						udf_release_data(bh);
						bh = NULL;
						break;
					}
				}
			}
			while (newfileset.logicalBlockNum < lastblock &&
				fileset->logicalBlockNum == 0xFFFFFFFF &&
				fileset->partitionReferenceNum == 0xFFFF);
		}
	}

	if ((fileset->logicalBlockNum != 0xFFFFFFFF ||
		fileset->partitionReferenceNum != 0xFFFF) && bh)
	{
		udf_debug("Fileset at block=%d, partition=%d\n",
			fileset->logicalBlockNum, fileset->partitionReferenceNum);

		UDF_SB_PARTITION(sb) = fileset->partitionReferenceNum;
		udf_load_fileset(sb, bh, root);
		udf_release_data(bh);
		return 0;
	}
	return 1;
}

static void 
udf_load_pvoldesc(struct super_block *sb, struct buffer_head *bh)
{
	struct primaryVolDesc *pvoldesc;
	time_t recording;
	long recording_usec;
	struct ustr instr;
	struct ustr outstr;

	pvoldesc = (struct primaryVolDesc *)bh->b_data;

	if ( udf_stamp_to_time(&recording, &recording_usec,
		lets_to_cpu(pvoldesc->recordingDateAndTime)) )
	{
		timestamp ts;
		ts = lets_to_cpu(pvoldesc->recordingDateAndTime);
		udf_debug("recording time %ld/%ld, %04u/%02u/%02u %02u:%02u (%x)\n",
			recording, recording_usec,
			ts.year, ts.month, ts.day, ts.hour, ts.minute, ts.typeAndTimezone);
		UDF_SB_RECORDTIME(sb).tv_sec = recording;
		UDF_SB_RECORDTIME(sb).tv_nsec = recording_usec * 1000;
	}

	if ( !udf_build_ustr(&instr, pvoldesc->volIdent, 32) )
	{
		if (udf_CS0toUTF8(&outstr, &instr))
		{
			strncpy( UDF_SB_VOLIDENT(sb), outstr.u_name,
				outstr.u_len > 31 ? 31 : outstr.u_len);
			udf_debug("volIdent[] = '%s'\n", UDF_SB_VOLIDENT(sb));
		}
	}

	if ( !udf_build_ustr(&instr, pvoldesc->volSetIdent, 128) )
	{
		if (udf_CS0toUTF8(&outstr, &instr))
			udf_debug("volSetIdent[] = '%s'\n", outstr.u_name);
	}
}

static void 
udf_load_fileset(struct super_block *sb, struct buffer_head *bh, lb_addr *root)
{
	struct fileSetDesc *fset;

	fset = (struct fileSetDesc *)bh->b_data;

	*root = lelb_to_cpu(fset->rootDirectoryICB.extLocation);

	UDF_SB_SERIALNUM(sb) = le16_to_cpu(fset->descTag.tagSerialNum);

	udf_debug("Rootdir at block=%d, partition=%d\n", 
		root->logicalBlockNum, root->partitionReferenceNum);
}

static void 
udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
{
	struct partitionDesc *p;
	int i;

	p = (struct partitionDesc *)bh->b_data;

	for (i=0; i<UDF_SB_NUMPARTS(sb); i++)
	{
		udf_debug("Searching map: (%d == %d)\n", 
			UDF_SB_PARTMAPS(sb)[i].s_partition_num, le16_to_cpu(p->partitionNumber));
		if (UDF_SB_PARTMAPS(sb)[i].s_partition_num == le16_to_cpu(p->partitionNumber))
		{
			UDF_SB_PARTLEN(sb,i) = le32_to_cpu(p->partitionLength); /* blocks */
			UDF_SB_PARTROOT(sb,i) = le32_to_cpu(p->partitionStartingLocation);
			if (le32_to_cpu(p->accessType) == PD_ACCESS_TYPE_READ_ONLY)
				UDF_SB_PARTFLAGS(sb,i) |= UDF_PART_FLAG_READ_ONLY;
			if (le32_to_cpu(p->accessType) == PD_ACCESS_TYPE_WRITE_ONCE)
				UDF_SB_PARTFLAGS(sb,i) |= UDF_PART_FLAG_WRITE_ONCE;
			if (le32_to_cpu(p->accessType) == PD_ACCESS_TYPE_REWRITABLE)
				UDF_SB_PARTFLAGS(sb,i) |= UDF_PART_FLAG_REWRITABLE;
			if (le32_to_cpu(p->accessType) == PD_ACCESS_TYPE_OVERWRITABLE)
				UDF_SB_PARTFLAGS(sb,i) |= UDF_PART_FLAG_OVERWRITABLE;

			if (!strcmp(p->partitionContents.ident, PD_PARTITION_CONTENTS_NSR02) ||
				!strcmp(p->partitionContents.ident, PD_PARTITION_CONTENTS_NSR03))
			{
				struct partitionHeaderDesc *phd;

				phd = (struct partitionHeaderDesc *)(p->partitionContentsUse);
				if (phd->unallocSpaceTable.extLength)
				{
					lb_addr loc = { le32_to_cpu(phd->unallocSpaceTable.extPosition), i };

					UDF_SB_PARTMAPS(sb)[i].s_uspace.s_table =
						udf_iget(sb, loc);
					UDF_SB_PARTFLAGS(sb,i) |= UDF_PART_FLAG_UNALLOC_TABLE;
					udf_debug("unallocSpaceTable (part %d) @ %ld\n",
						i, UDF_SB_PARTMAPS(sb)[i].s_uspace.s_table->i_ino);
				}
				if (phd->unallocSpaceBitmap.extLength)
				{
					UDF_SB_ALLOC_BITMAP(sb, i, s_uspace);
					if (UDF_SB_PARTMAPS(sb)[i].s_uspace.s_bitmap != NULL)
					{
						UDF_SB_PARTMAPS(sb)[i].s_uspace.s_bitmap->s_extLength =
							le32_to_cpu(phd->unallocSpaceBitmap.extLength);
						UDF_SB_PARTMAPS(sb)[i].s_uspace.s_bitmap->s_extPosition =
							le32_to_cpu(phd->unallocSpaceBitmap.extPosition);
						UDF_SB_PARTFLAGS(sb,i) |= UDF_PART_FLAG_UNALLOC_BITMAP;
						udf_debug("unallocSpaceBitmap (part %d) @ %d\n",