bcachefs: Run merges at BCH_WATERMARK_btree

This fixes a deadlock where the interior update path during journal
replay ends up doing a ton of merges on the backpointers btree, and
deadlocking.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index 29a5bc7d878984765bf417e61cc0a9c02f9220f0..1a7537ee432971df5f78520de08acb7e88477f46 100644 (file)
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -1926,6 +1926,8 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
        BUG_ON(!trans->paths[path].should_be_locked);
        BUG_ON(!btree_node_locked(&trans->paths[path], level));
 
+       flags &= ~BCH_WATERMARK_MASK;
+
        b = trans->paths[path].l[level].b;
 
        if ((sib == btree_prev_sib && bpos_eq(b->data->min_key, POS_MIN)) ||
@@ -2071,6 +2073,10 @@ err:
                bch2_path_put(trans, new_path, true);
        bch2_path_put(trans, sib_path, true);
        bch2_trans_verify_locks(trans);
+       if (ret == -BCH_ERR_journal_reclaim_would_deadlock)
+               ret = 0;
+       if (!ret)
+               ret = bch2_trans_relock(trans);
        return ret;
 err_free_update:
        bch2_btree_node_free_never_used(as, trans, n);