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: Steven J. Magnani <steve@digidescorp.com> Link: https://lore.kernel.org/r/20190711133852.16887-1-steve@digidescorp.com Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Steven J. Magnani
Jan Kara
Родитель
609488bc97
Коммит
ba54aef031
128
fs/udf/super.c
128
fs/udf/super.c
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@ -646,16 +646,67 @@ out_unlock:
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return error;
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}
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/* Check Volume Structure Descriptors (ECMA 167 2/9.1) */
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/* We also check any "CD-ROM Volume Descriptor Set" (ECMA 167 2/8.3.1) */
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static loff_t udf_check_vsd(struct super_block *sb)
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/*
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* Check VSD descriptor. Returns -1 in case we are at the end of volume
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* recognition area, 0 if the descriptor is valid but non-interesting, 1 if
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* we found one of NSR descriptors we are looking for.
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*/
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static int identify_vsd(const struct volStructDesc *vsd)
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{
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int ret = 0;
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if (!memcmp(vsd->stdIdent, VSD_STD_ID_CD001, VSD_STD_ID_LEN)) {
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switch (vsd->structType) {
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case 0:
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udf_debug("ISO9660 Boot Record found\n");
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break;
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case 1:
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udf_debug("ISO9660 Primary Volume Descriptor found\n");
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break;
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case 2:
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udf_debug("ISO9660 Supplementary Volume Descriptor found\n");
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break;
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case 3:
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udf_debug("ISO9660 Volume Partition Descriptor found\n");
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break;
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case 255:
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udf_debug("ISO9660 Volume Descriptor Set Terminator found\n");
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break;
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default:
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udf_debug("ISO9660 VRS (%u) found\n", vsd->structType);
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break;
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}
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} else if (!memcmp(vsd->stdIdent, VSD_STD_ID_BEA01, VSD_STD_ID_LEN))
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; /* ret = 0 */
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else if (!memcmp(vsd->stdIdent, VSD_STD_ID_NSR02, VSD_STD_ID_LEN))
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ret = 1;
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else if (!memcmp(vsd->stdIdent, VSD_STD_ID_NSR03, VSD_STD_ID_LEN))
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ret = 1;
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else if (!memcmp(vsd->stdIdent, VSD_STD_ID_BOOT2, VSD_STD_ID_LEN))
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; /* ret = 0 */
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else if (!memcmp(vsd->stdIdent, VSD_STD_ID_CDW02, VSD_STD_ID_LEN))
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; /* ret = 0 */
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else {
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/* TEA01 or invalid id : end of volume recognition area */
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ret = -1;
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}
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return ret;
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}
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/*
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* Check Volume Structure Descriptors (ECMA 167 2/9.1)
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* We also check any "CD-ROM Volume Descriptor Set" (ECMA 167 2/8.3.1)
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* @return 1 if NSR02 or NSR03 found,
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* -1 if first sector read error, 0 otherwise
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*/
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static int udf_check_vsd(struct super_block *sb)
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{
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struct volStructDesc *vsd = NULL;
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loff_t sector = VSD_FIRST_SECTOR_OFFSET;
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int sectorsize;
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struct buffer_head *bh = NULL;
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int nsr02 = 0;
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int nsr03 = 0;
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int nsr = 0;
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struct udf_sb_info *sbi;
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sbi = UDF_SB(sb);
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@ -679,71 +730,20 @@ static loff_t udf_check_vsd(struct super_block *sb)
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* activity. This actually happened with uninitialised SSD partitions
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* (all 0xFF) before the check for the limit and all valid IDs were
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* added */
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for (; !nsr02 && !nsr03 && sector < VSD_MAX_SECTOR_OFFSET;
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sector += sectorsize) {
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for (; !nsr && sector < VSD_MAX_SECTOR_OFFSET; sector += sectorsize) {
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/* Read a block */
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bh = udf_tread(sb, sector >> sb->s_blocksize_bits);
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if (!bh)
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break;
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/* Look for ISO descriptors */
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vsd = (struct volStructDesc *)(bh->b_data +
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(sector & (sb->s_blocksize - 1)));
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if (!strncmp(vsd->stdIdent, VSD_STD_ID_CD001,
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VSD_STD_ID_LEN)) {
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switch (vsd->structType) {
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case 0:
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udf_debug("ISO9660 Boot Record found\n");
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break;
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case 1:
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udf_debug("ISO9660 Primary Volume Descriptor found\n");
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break;
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case 2:
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udf_debug("ISO9660 Supplementary Volume Descriptor found\n");
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break;
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case 3:
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udf_debug("ISO9660 Volume Partition Descriptor found\n");
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break;
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case 255:
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udf_debug("ISO9660 Volume Descriptor Set Terminator found\n");
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break;
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default:
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udf_debug("ISO9660 VRS (%u) found\n",
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vsd->structType);
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break;
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}
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} else if (!strncmp(vsd->stdIdent, VSD_STD_ID_BEA01,
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VSD_STD_ID_LEN))
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; /* nothing */
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else if (!strncmp(vsd->stdIdent, VSD_STD_ID_TEA01,
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VSD_STD_ID_LEN)) {
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brelse(bh);
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break;
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} else if (!strncmp(vsd->stdIdent, VSD_STD_ID_NSR02,
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VSD_STD_ID_LEN))
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nsr02 = sector;
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else if (!strncmp(vsd->stdIdent, VSD_STD_ID_NSR03,
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VSD_STD_ID_LEN))
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nsr03 = sector;
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else if (!strncmp(vsd->stdIdent, VSD_STD_ID_BOOT2,
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VSD_STD_ID_LEN))
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; /* nothing */
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else if (!strncmp(vsd->stdIdent, VSD_STD_ID_CDW02,
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VSD_STD_ID_LEN))
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; /* nothing */
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else {
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/* invalid id : end of volume recognition area */
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brelse(bh);
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break;
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}
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nsr = identify_vsd(vsd);
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brelse(bh);
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}
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if (nsr03)
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return nsr03;
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else if (nsr02)
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return nsr02;
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if (nsr > 0)
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return 1;
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else if (!bh && sector - (sbi->s_session << sb->s_blocksize_bits) ==
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VSD_FIRST_SECTOR_OFFSET)
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return -1;
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@ -1915,7 +1915,7 @@ static int udf_load_vrs(struct super_block *sb, struct udf_options *uopt,
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int silent, struct kernel_lb_addr *fileset)
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{
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struct udf_sb_info *sbi = UDF_SB(sb);
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loff_t nsr_off;
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int nsr = 0;
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int ret;
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if (!sb_set_blocksize(sb, uopt->blocksize)) {
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@ -1926,13 +1926,13 @@ static int udf_load_vrs(struct super_block *sb, struct udf_options *uopt,
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sbi->s_last_block = uopt->lastblock;
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if (!uopt->novrs) {
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/* Check that it is NSR02 compliant */
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nsr_off = udf_check_vsd(sb);
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if (!nsr_off) {
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nsr = udf_check_vsd(sb);
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if (!nsr) {
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if (!silent)
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udf_warn(sb, "No VRS found\n");
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return -EINVAL;
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}
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if (nsr_off == -1)
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if (nsr == -1)
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udf_debug("Failed to read sector at offset %d. "
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"Assuming open disc. Skipping validity "
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"check\n", VSD_FIRST_SECTOR_OFFSET);
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