[PATCH 4/4] bcachefs: bch2_move_data_btree() can now walk roots

[Kent Overstreet]

Signed-off-by: Kent Overstreet <kent.overstr...@linux.dev>
---
 fs/bcachefs/move.c | 47 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/fs/bcachefs/move.c b/fs/bcachefs/move.c
index b594c9ed41f8..f605bd014868 100644
--- a/fs/bcachefs/move.c
+++ b/fs/bcachefs/move.c
@@ -606,7 +606,52 @@ int bch2_move_data_btree(struct moving_context *ctxt,
                ctxt->stats->pos        = BBPOS(btree_id, start);
        }
 
+retry_root:
        bch2_trans_begin(trans);
+
+       if (level == bch2_btree_id_root(c, btree_id)->level + 1) {
+               bch2_trans_node_iter_init(trans, &iter, btree_id, start, 0, 
level - 1,
+                                         BTREE_ITER_prefetch|
+                                         BTREE_ITER_not_extents|
+                                         BTREE_ITER_all_snapshots);
+               struct btree *b = bch2_btree_iter_peek_node(trans, &iter);
+               ret = PTR_ERR_OR_ZERO(b);
+               if (ret)
+                       goto root_err;
+
+               if (b != btree_node_root(c, b)) {
+                       bch2_trans_iter_exit(trans, &iter);
+                       goto retry_root;
+               }
+
+               k = bkey_i_to_s_c(&b->key);
+
+               io_opts = bch2_move_get_io_opts(trans, &snapshot_io_opts,
+                                               iter.pos, &iter, k);
+               ret = PTR_ERR_OR_ZERO(io_opts);
+               if (ret)
+                       goto root_err;
+
+               memset(&data_opts, 0, sizeof(data_opts));
+               if (!pred(c, arg, iter.btree_id, k, io_opts, &data_opts))
+                       goto out;
+
+
+               if (!data_opts.scrub)
+                       ret = bch2_btree_node_rewrite_pos(trans, btree_id, 
level,
+                                                         k.k->p, 
data_opts.target, 0);
+               else
+                       ret = bch2_btree_node_scrub(trans, btree_id, level, k, 
data_opts.read_dev);
+
+root_err:
+               if (bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
+                       bch2_trans_iter_exit(trans, &iter);
+                       goto retry_root;
+               }
+
+               goto out;
+       }
+
        bch2_trans_node_iter_init(trans, &iter, btree_id, start, 0, level,
                                  BTREE_ITER_prefetch|
                                  BTREE_ITER_not_extents|
@@ -707,7 +752,7 @@ int bch2_move_data_btree(struct moving_context *ctxt,
 next_nondata:
                bch2_btree_iter_advance(trans, &iter);
        }
-
+out:
        bch2_trans_iter_exit(trans, &reflink_iter);
        bch2_trans_iter_exit(trans, &iter);
        bch2_bkey_buf_exit(&sk, c);
-- 
2.49.0