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Commit ba54aef0 authored by Steven J. Magnani's avatar Steven J. Magnani Committed by Jan Kara
Browse files

udf: refactor VRS descriptor identification 



Extract code that parses a Volume Recognition Sequence descriptor
(component), in preparation for calling it twice against different
locations in a block.

Signed-off-by: default avatarSteven J. Magnani <steve@digidescorp.com>
Link: https://lore.kernel.org/r/20190711133852.16887-1-steve@digidescorp.com


Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 609488bc

fs/udf/super.c

+64 −64
Original line number Diff line number Diff line
@@ -646,16 +646,67 @@ static int udf_remount_fs(struct super_block *sb, int *flags, char *options) 
	return error;

}



/* Check Volume Structure Descriptors (ECMA 167 2/9.1) */

/* We also check any "CD-ROM Volume Descriptor Set" (ECMA 167 2/8.3.1) */

static loff_t udf_check_vsd(struct super_block *sb)

/*

 * Check VSD descriptor. Returns -1 in case we are at the end of volume

 * recognition area, 0 if the descriptor is valid but non-interesting, 1 if

 * we found one of NSR descriptors we are looking for.

 */

static int identify_vsd(const struct volStructDesc *vsd)

{

	int ret = 0;



	if (!memcmp(vsd->stdIdent, VSD_STD_ID_CD001, VSD_STD_ID_LEN)) {

		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 (!memcmp(vsd->stdIdent, VSD_STD_ID_BEA01, VSD_STD_ID_LEN))

		; /* ret = 0 */

	else if (!memcmp(vsd->stdIdent, VSD_STD_ID_NSR02, VSD_STD_ID_LEN))

		ret = 1;

	else if (!memcmp(vsd->stdIdent, VSD_STD_ID_NSR03, VSD_STD_ID_LEN))

		ret = 1;

	else if (!memcmp(vsd->stdIdent, VSD_STD_ID_BOOT2, VSD_STD_ID_LEN))

		; /* ret = 0 */

	else if (!memcmp(vsd->stdIdent, VSD_STD_ID_CDW02, VSD_STD_ID_LEN))

		; /* ret = 0 */

	else {

		/* TEA01 or invalid id : end of volume recognition area */

		ret = -1;

	}



	return ret;

}



/*

 * Check Volume Structure Descriptors (ECMA 167 2/9.1)

 * We also check any "CD-ROM Volume Descriptor Set" (ECMA 167 2/8.3.1)

 * @return   1 if NSR02 or NSR03 found,

 *	    -1 if first sector read error, 0 otherwise

 */

static int udf_check_vsd(struct super_block *sb)

{

	struct volStructDesc *vsd = NULL;

	loff_t sector = VSD_FIRST_SECTOR_OFFSET;

	int sectorsize;

	struct buffer_head *bh = NULL;

	int nsr02 = 0;

	int nsr03 = 0;

	int nsr = 0;

	struct udf_sb_info *sbi;



	sbi = UDF_SB(sb);
@@ -679,71 +730,20 @@ static loff_t udf_check_vsd(struct super_block *sb) 
	 * activity. This actually happened with uninitialised SSD partitions

	 * (all 0xFF) before the check for the limit and all valid IDs were

	 * added */

	for (; !nsr02 && !nsr03 && sector < VSD_MAX_SECTOR_OFFSET;

	     sector += sectorsize) {

	for (; !nsr && sector < VSD_MAX_SECTOR_OFFSET; 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 (!strncmp(vsd->stdIdent, VSD_STD_ID_CD001,

				    VSD_STD_ID_LEN)) {

			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))

			; /* nothing */

		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;

		else if (!strncmp(vsd->stdIdent, VSD_STD_ID_BOOT2,

				    VSD_STD_ID_LEN))

			; /* nothing */

		else if (!strncmp(vsd->stdIdent, VSD_STD_ID_CDW02,

				    VSD_STD_ID_LEN))

			; /* nothing */

		else {

			/* invalid id : end of volume recognition area */

			brelse(bh);

			break;

		}

		nsr = identify_vsd(vsd);

		brelse(bh);

	}



	if (nsr03)

		return nsr03;

	else if (nsr02)

		return nsr02;

	if (nsr > 0)

		return 1;

	else if (!bh && sector - (sbi->s_session << sb->s_blocksize_bits) ==

			VSD_FIRST_SECTOR_OFFSET)

		return -1;
@@ -1915,7 +1915,7 @@ static int udf_load_vrs(struct super_block *sb, struct udf_options *uopt, 
			int silent, struct kernel_lb_addr *fileset)

{

	struct udf_sb_info *sbi = UDF_SB(sb);

	loff_t nsr_off;

	int nsr = 0;

	int ret;



	if (!sb_set_blocksize(sb, uopt->blocksize)) {
@@ -1926,13 +1926,13 @@ static int udf_load_vrs(struct super_block *sb, struct udf_options *uopt, 
	sbi->s_last_block = uopt->lastblock;

	if (!uopt->novrs) {

		/* Check that it is NSR02 compliant */

		nsr_off = udf_check_vsd(sb);

		if (!nsr_off) {

		nsr = udf_check_vsd(sb);

		if (!nsr) {

			if (!silent)

				udf_warn(sb, "No VRS found\n");

			return -EINVAL;

		}

		if (nsr_off == -1)

		if (nsr == -1)

			udf_debug("Failed to read sector at offset %d. "

				  "Assuming open disc. Skipping validity "

				  "check\n", VSD_FIRST_SECTOR_OFFSET);