diff --git a/fs/bcachefs/btree_cache.c b/fs/bcachefs/btree_cache.c
index ca755e8d1a37..9761dc05ba07 100644
--- a/fs/bcachefs/btree_cache.c
+++ b/fs/bcachefs/btree_cache.c
@@ -794,17 +794,17 @@ struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_rea
                        goto got_node;
                }
 
+       mutex_unlock(&bc->lock);
        b = __btree_node_mem_alloc(c, GFP_NOWAIT|__GFP_NOWARN);
        if (!b) {
-               mutex_unlock(&bc->lock);
                bch2_trans_unlock(trans);
                b = __btree_node_mem_alloc(c, GFP_KERNEL);
                if (!b)
                        goto err;
-               mutex_lock(&bc->lock);
        }
 
        bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0);
+       mutex_lock(&bc->lock);
 
        BUG_ON(!six_trylock_intent(&b->c.lock));
        BUG_ON(!six_trylock_write(&b->c.lock));