}
/*
- * 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.
+ * Check whether there is an anchor block in the given block
*/
-static void udf_find_anchor(struct super_block *sb)
+static int udf_check_anchor_block(struct super_block *sb, sector_t block,
+ bool varconv)
{
- int lastblock;
struct buffer_head *bh = NULL;
+ tag *t;
uint16_t ident;
uint32_t location;
+
+ if (varconv)
+ bh = sb_bread(sb, udf_fixed_to_variable(block));
+ else
+ bh = sb_bread(sb, block);
+
+ if (!bh)
+ return 0;
+
+ t = (tag *)bh->b_data;
+ ident = le16_to_cpu(t->tagIdent);
+ location = le32_to_cpu(t->tagLocation);
+ brelse(bh);
+ if (ident != TAG_IDENT_AVDP)
+ return 0;
+ return location == block;
+}
+
+/* Search for an anchor volume descriptor pointer */
+static sector_t udf_scan_anchors(struct super_block *sb, bool varconv,
+ sector_t lastblock)
+{
+ sector_t last[4];
int i;
- struct udf_sb_info *sbi;
+ struct udf_sb_info *sbi = UDF_SB(sb);
- sbi = UDF_SB(sb);
- lastblock = sbi->s_last_block;
+ last[0] = lastblock;
+ last[1] = last[0] - 2;
+ last[2] = last[0] - 150;
+ last[3] = last[0] - 152;
- 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++) {
- ident = location = 0;
- if (last[i] >= 0) {
- bh = sb_bread(sb, last[i]);
- if (bh) {
- tag *t = (tag *)bh->b_data;
- ident = le16_to_cpu(t->tagIdent);
- location = le32_to_cpu(t->tagLocation);
- brelse(bh);
- }
- }
+ /* according to spec, anchor is in either:
+ * block 256
+ * lastblock-256
+ * lastblock
+ * however, if the disc isn't closed, it could be 512 */
- if (ident == TAG_IDENT_AVDP) {
- if (location == last[i] - sbi->s_session) {
- lastblock = last[i] - sbi->s_session;
- sbi->s_anchor[0] = lastblock;
- sbi->s_anchor[1] = lastblock - 256;
- } else if (location ==
- udf_variable_to_fixed(last[i]) -
- sbi->s_session) {
- UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
- lastblock =
- udf_variable_to_fixed(last[i]) -
- sbi->s_session;
- sbi->s_anchor[0] = lastblock;
- sbi->s_anchor[1] = lastblock - 256 -
- sbi->s_session;
- } 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];
- sbi->s_anchor[3] = 512;
- } else {
- ident = location = 0;
- if (last[i] >= 256) {
- bh = sb_bread(sb, last[i] - 256);
- if (bh) {
- tag *t = (tag *)bh->b_data;
- ident = le16_to_cpu(
- t->tagIdent);
- location = le32_to_cpu(
- t->tagLocation);
- brelse(bh);
- }
- }
+ for (i = 0; i < ARRAY_SIZE(last); i++) {
+ if (last[i] < 0)
+ continue;
- if (ident == TAG_IDENT_AVDP &&
- location == last[i] - 256 -
- sbi->s_session) {
- lastblock = last[i];
- sbi->s_anchor[1] = last[i] - 256;
- } else {
- ident = location = 0;
- if (last[i] >= 312 + sbi->s_session) {
- bh = sb_bread(sb,
- last[i] - 312 -
- sbi->s_session);
- if (bh) {
- tag *t = (tag *)
- bh->b_data;
- ident = le16_to_cpu(
- t->tagIdent);
- location = le32_to_cpu(
- t->tagLocation);
- brelse(bh);
- }
- }
+ if (udf_check_anchor_block(sb, last[i], varconv)) {
+ sbi->s_anchor[0] = last[i];
+ sbi->s_anchor[1] = last[i] - 256;
+ return last[i];
+ }
- 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]);
- sbi->s_anchor[1] = lastblock - 256;
- }
- }
- }
+ if (last[i] < 256)
+ continue;
+
+ if (udf_check_anchor_block(sb, last[i] - 256, varconv)) {
+ sbi->s_anchor[1] = last[i] - 256;
+ return last[i];
}
}
- if (!lastblock) {
- /* We haven't found the lastblock. check 312 */
- bh = sb_bread(sb, 312 + sbi->s_session);
- if (bh) {
- tag *t = (tag *)bh->b_data;
- ident = le16_to_cpu(t->tagIdent);
- location = le32_to_cpu(t->tagLocation);
- brelse(bh);
+ if (udf_check_anchor_block(sb, sbi->s_session + 256, varconv)) {
+ sbi->s_anchor[0] = sbi->s_session + 256;
+ return last[0];
+ }
+ if (udf_check_anchor_block(sb, sbi->s_session + 512, varconv)) {
+ sbi->s_anchor[0] = sbi->s_session + 512;
+ return last[0];
+ }
+ return 0;
+}
- if (ident == TAG_IDENT_AVDP && location == 256)
- UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
- }
+/*
+ * Find an anchor volume descriptor. The function expects sbi->s_lastblock to
+ * be the last block on the media.
+ *
+ * Return 1 if not found, 0 if ok
+ *
+ */
+static void udf_find_anchor(struct super_block *sb)
+{
+ sector_t lastblock;
+ struct buffer_head *bh = NULL;
+ uint16_t ident;
+ int i;
+ struct udf_sb_info *sbi = UDF_SB(sb);
+
+ lastblock = udf_scan_anchors(sb, 0, sbi->s_last_block);
+ if (lastblock)
+ goto check_anchor;
+
+ /* No anchor found? Try VARCONV conversion of block numbers */
+ /* Firstly, we try to not convert number of the last block */
+ lastblock = udf_scan_anchors(sb, 1,
+ udf_variable_to_fixed(sbi->s_last_block));
+ if (lastblock) {
+ UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
+ goto check_anchor;
}
+ /* Secondly, we try with converted number of the last block */
+ lastblock = udf_scan_anchors(sb, 1, sbi->s_last_block);
+ if (lastblock)
+ UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
+
+check_anchor:
+ /*
+ * Check located anchors and the anchor block supplied via
+ * mount options
+ */
for (i = 0; i < ARRAY_SIZE(sbi->s_anchor); i++) {
if (!sbi->s_anchor[i])
continue;
sbi->s_anchor[i] = 0;
else {
brelse(bh);
- if ((ident != TAG_IDENT_AVDP) &&
- (i || (ident != TAG_IDENT_FE &&
- ident != TAG_IDENT_EFE)))
+ if (ident != TAG_IDENT_AVDP)
sbi->s_anchor[i] = 0;
}
}
if (ret)
goto out_bh;
- if (!sbi->s_last_block) {
- sbi->s_last_block = udf_get_last_block(sb);
- udf_find_anchor(sb);
- if (!sbi->s_last_block) {
- udf_debug("Unable to determine Lastblock (For "
- "Virtual Partition)\n");
- ret = 1;
- goto out_bh;
- }
- }
-
ret = udf_load_vat(sb, i, type1_idx);
out_bh:
/* In case loading failed, we handle cleanup in udf_fill_super */
sbi->s_last_block = uopt.lastblock;
sbi->s_anchor[0] = sbi->s_anchor[1] = 0;
sbi->s_anchor[2] = uopt.anchor;
- sbi->s_anchor[3] = 256;
if (udf_check_valid(sb, uopt.novrs, silent)) {
/* read volume recognition sequences */
projects / linux-2.6-omap-h63xx.git / blobdiff