From: Jan Kara <jack@xxxxxxx>
commit 53cafe1d6d8ef9f93318e5bfccc0d24f27d41ced upstream.
When merging very long extents we try to push as much length as possible
to the first extent. However this is unnecessarily complicated and not
really worth the trouble. Furthermore there was a bug in the logic
resulting in corrupting extents in the file as syzbot reproducer shows.
So just don't bother with the merging of extents that are too long
together.
CC: stable@xxxxxxxxxxxxxxx
Reported-by: syzbot+60f291a24acecb3c2bd5@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/udf/inode.c | 19 ++-----------------
1 file changed, 2 insertions(+), 17 deletions(-)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1093,23 +1093,8 @@ static void udf_merge_extents(struct ino
blocksize - 1) >> blocksize_bits)))) {
if (((li->extLength & UDF_EXTENT_LENGTH_MASK) +
- (lip1->extLength & UDF_EXTENT_LENGTH_MASK) +
- blocksize - 1) & ~UDF_EXTENT_LENGTH_MASK) {
- lip1->extLength = (lip1->extLength -
- (li->extLength &
- UDF_EXTENT_LENGTH_MASK) +
- UDF_EXTENT_LENGTH_MASK) &
- ~(blocksize - 1);
- li->extLength = (li->extLength &
- UDF_EXTENT_FLAG_MASK) +
- (UDF_EXTENT_LENGTH_MASK + 1) -
- blocksize;
- lip1->extLocation.logicalBlockNum =
- li->extLocation.logicalBlockNum +
- ((li->extLength &
- UDF_EXTENT_LENGTH_MASK) >>
- blocksize_bits);
- } else {
+ (lip1->extLength & UDF_EXTENT_LENGTH_MASK) +
+ blocksize - 1) <= UDF_EXTENT_LENGTH_MASK) {
li->extLength = lip1->extLength +
(((li->extLength &
UDF_EXTENT_LENGTH_MASK) +
