udf: Fix directory iteration for longer tail extents

commit 1ea1cd11c72d1405a6b98440a9d5ea82dfa07166 upstream.

When directory's last extent has more that one block and its length is
not multiple of a block side, the code wrongly decided to move to the
next extent instead of processing the last partial block. This led to
directory corruption. Fix the rounding issue.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Shreenidhi Shedi <yesshedi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/udf/directory.c b/fs/udf/directory.c
index 04169e428fdfa1523aa067ef38fca3a28aebb049..76dd2e35e09817cd563c792b0c9a4e09423179e8 100644 (file)
--- a/fs/udf/directory.c
+++ b/fs/udf/directory.c
@@ -170,7 +170,7 @@ static struct buffer_head *udf_fiiter_bread_blk(struct udf_fileident_iter *iter)
 static int udf_fiiter_advance_blk(struct udf_fileident_iter *iter)
 {
        iter->loffset++;
-       if (iter->loffset < iter->elen >> iter->dir->i_blkbits)
+       if (iter->loffset < DIV_ROUND_UP(iter->elen, 1<<iter->dir->i_blkbits))
                return 0;
 
        iter->loffset = 0;