udf: Fix regression in UDF anchor block detection
In some cases it could happen that some block passed test in
udf_check_anchor_block() even though udf_read_tagged() refused to read it later
(e.g. because checksum was not correct). This patch makes
udf_check_anchor_block() use udf_read_tagged() so that the checking is
stricter.
This fixes the regression (certain disks unmountable) caused by commit
423cf6dc04eb79d441bfda2b127bc4b57134b41d.
Signed-off-by: Tomas Janousek <tomi@nomi.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 7a5f69b..44cc702 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -682,38 +682,26 @@
/*
* Check whether there is an anchor block in the given block
*/
-static int udf_check_anchor_block(struct super_block *sb, sector_t block,
- bool varconv)
+static int udf_check_anchor_block(struct super_block *sb, sector_t block)
{
- struct buffer_head *bh = NULL;
- tag *t;
+ struct buffer_head *bh;
uint16_t ident;
- uint32_t location;
- if (varconv) {
- if (udf_fixed_to_variable(block) >=
- sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits)
- return 0;
- bh = sb_bread(sb, udf_fixed_to_variable(block));
- }
- else
- bh = sb_bread(sb, block);
+ if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV) &&
+ udf_fixed_to_variable(block) >=
+ sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits)
+ return 0;
+ bh = udf_read_tagged(sb, block, block, &ident);
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;
+
+ return ident == TAG_IDENT_AVDP;
}
/* Search for an anchor volume descriptor pointer */
-static sector_t udf_scan_anchors(struct super_block *sb, bool varconv,
- sector_t lastblock)
+static sector_t udf_scan_anchors(struct super_block *sb, sector_t lastblock)
{
sector_t last[6];
int i;
@@ -739,7 +727,7 @@
sb->s_blocksize_bits)
continue;
- if (udf_check_anchor_block(sb, last[i], varconv)) {
+ if (udf_check_anchor_block(sb, last[i])) {
sbi->s_anchor[0] = last[i];
sbi->s_anchor[1] = last[i] - 256;
return last[i];
@@ -748,17 +736,17 @@
if (last[i] < 256)
continue;
- if (udf_check_anchor_block(sb, last[i] - 256, varconv)) {
+ if (udf_check_anchor_block(sb, last[i] - 256)) {
sbi->s_anchor[1] = last[i] - 256;
return last[i];
}
}
- if (udf_check_anchor_block(sb, sbi->s_session + 256, varconv)) {
+ if (udf_check_anchor_block(sb, sbi->s_session + 256)) {
sbi->s_anchor[0] = sbi->s_session + 256;
return last[0];
}
- if (udf_check_anchor_block(sb, sbi->s_session + 512, varconv)) {
+ if (udf_check_anchor_block(sb, sbi->s_session + 512)) {
sbi->s_anchor[0] = sbi->s_session + 512;
return last[0];
}
@@ -780,23 +768,24 @@
int i;
struct udf_sb_info *sbi = UDF_SB(sb);
- lastblock = udf_scan_anchors(sb, 0, sbi->s_last_block);
+ lastblock = udf_scan_anchors(sb, sbi->s_last_block);
if (lastblock)
goto check_anchor;
/* No anchor found? Try VARCONV conversion of block numbers */
+ UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
/* Firstly, we try to not convert number of the last block */
- lastblock = udf_scan_anchors(sb, 1,
+ lastblock = udf_scan_anchors(sb,
udf_variable_to_fixed(sbi->s_last_block));
- if (lastblock) {
- UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
+ if (lastblock)
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);
+ lastblock = udf_scan_anchors(sb, sbi->s_last_block);
+ if (!lastblock) {
+ /* VARCONV didn't help. Clear it. */
+ UDF_CLEAR_FLAG(sb, UDF_FLAG_VARCONV);
+ }
check_anchor:
/*