udf: Fix extension of the last extent in the file

[ Upstream commit 83c7423d1eb6806d13c521d1002cc1a012111719 ]

When extending the last extent in the file within the last block, we
wrongly computed the length of the last extent. This is mostly a
cosmetical problem since the extent does not contain any data and the
length will be fixed up by following operations but still.

Fixes: 1f3868f06855 ("udf: Fix extending file within last block")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index f713d10..e92a164 100644 (file)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -600,7 +600,7 @@ static void udf_do_extend_final_block(struct inode *inode,
         */
        if (new_elen <= (last_ext->extLength & UDF_EXTENT_LENGTH_MASK))
                return;
-       added_bytes = (last_ext->extLength & UDF_EXTENT_LENGTH_MASK) - new_elen;
+       added_bytes = new_elen - (last_ext->extLength & UDF_EXTENT_LENGTH_MASK);
        last_ext->extLength += added_bytes;
        UDF_I(inode)->i_lenExtents += added_bytes;