btrfs: remove pointless initialization at btrfs_qgroup_trace_extent()

The qgroup record was allocated with kzalloc(), so it's pointless to set
its old_roots member to NULL. Remove the assignment.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index f7b05c7ee4284df681cd1818c1e3fc61ed50fea6..8773f989c3be24734933462b1c2cd7a5ef585a98 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2156,7 +2156,6 @@ int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
        }
 
        record->num_bytes = num_bytes;
-       record->old_roots = NULL;
 
        ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, record, bytenr);
        if (ret) {