Btrfs: copy string correctly in INO_LOOKUP ioctl

Memory areas [ptr, ptr+total_len] and [name, name+total_len]
may overlap, so it's wrong to use memcpy().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index fd252fff4c66..2bb08862a4f6 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1757,11 +1757,10 @@ static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
                 key.objectid = key.offset;
                 key.offset = (u64)-1;
                 dirid = key.objectid;
-
         }
         if (ptr < name)
                 goto out;
-        memcpy(name, ptr, total_len);
+        memmove(name, ptr, total_len);
         name[total_len]='\0';
         ret = 0;
 out: