super.c

linux 内核源代码

static int udf_remount_fs(struct super_block *sb, int *flags, char *options)
{
	struct udf_options uopt;

	uopt.flags = UDF_SB(sb)->s_flags;
	uopt.uid   = UDF_SB(sb)->s_uid;
	uopt.gid   = UDF_SB(sb)->s_gid;
	uopt.umask = UDF_SB(sb)->s_umask;

	if (!udf_parse_options(options, &uopt))
		return -EINVAL;

	UDF_SB(sb)->s_flags = uopt.flags;
	UDF_SB(sb)->s_uid   = uopt.uid;
	UDF_SB(sb)->s_gid   = uopt.gid;
	UDF_SB(sb)->s_umask = uopt.umask;

	if (UDF_SB_LVIDBH(sb)) {
		int write_rev = le16_to_cpu(UDF_SB_LVIDIU(sb)->minUDFWriteRev);
		if (write_rev > UDF_MAX_WRITE_VERSION)
			*flags |= MS_RDONLY;
	}

	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
		return 0;
	if (*flags & MS_RDONLY)
		udf_close_lvid(sb);
	else
		udf_open_lvid(sb);

	return 0;
}

/*
 * udf_set_blocksize
 *
 * PURPOSE
 *	Set the block size to be used in all transfers.
 *
 * DESCRIPTION
 *	To allow room for a DMA transfer, it is best to guess big when unsure.
 *	This routine picks 2048 bytes as the blocksize when guessing. This
 *	should be adequate until devices with larger block sizes become common.
 *
 *	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) {
			brelse(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)) {
			brelse(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;
		}
		brelse(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 < ARRAY_SIZE(last); 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);
				brelse(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);
					brelse(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);
						brelse(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);
			brelse(bh);

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

	for (i = 0; i < ARRAY_SIZE(UDF_SB_ANCHOR(sb)); 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 {
				brelse(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, kernel_lb_addr *fileset, kernel_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) {
			brelse(bh);
			return 1;
		}

	}

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

/* --> cvg: FIXME - is it reasonable? */
		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);
					brelse(bh);
					break;
				}
				case TAG_IDENT_FSD:
					*fileset = newfileset;
					break;
				default:
					newfileset.logicalBlockNum++;
					brelse(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);
		brelse(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))) {
		kernel_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,
			     kernel_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 int 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) {
					kernel_lb_addr loc = {
						.logicalBlockNum = le32_to_cpu(phd->unallocSpaceTable.extPosition),
						.partitionReferenceNum = i,
					};

					UDF_SB_PARTMAPS(sb)[i].s_uspace.s_table =
						udf_iget(sb, loc);
					if (!UDF_SB_PARTMAPS(sb)[i].s_uspace.s_table) {
						udf_debug("cannot load unallocSpaceTable (part %d)\n", i);
						return 1;
					}