ext4: initialize moved_len before calling ext4_move_extents()

The move_extent.moved_len is used to pass back the number of exchanged
blocks count to user space.  Currently the caller must clear this
field; but we spend more code space checking for this requirement than
simply zeroing the field ourselves, so let's just make life easier for
everyone all around.

Signed-off-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: Akira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index c1cdf613e725..31e5ee0c858f 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -239,6 +239,7 @@ setversion_out:
                         }
                 }
 
+                me.moved_len = 0;
                 err = ext4_move_extents(filp, donor_filp, me.orig_start,
                                         me.donor_start, me.len, &me.moved_len);
                 fput(donor_filp);