btree_write_buffer: ensure atomic64_sub_return_release availability

[bcachefs-tools-debian] / libbcachefs / btree_iter.c

diff --git a/libbcachefs/btree_iter.c b/libbcachefs/btree_iter.c
index feba9a315c8ce0657de9cd30322aa47f3f420af4..ba392eb02a57b53493cf6e91fab14b513b51083f 100644 (file)
--- a/libbcachefs/btree_iter.c
+++ b/libbcachefs/btree_iter.c
@@ -1109,6 +1109,9 @@ int bch2_btree_path_traverse_one(struct btree_trans *trans,
        if (unlikely(ret))
                goto out;
 
+       if (unlikely(!trans->srcu_held))
+               bch2_trans_srcu_lock(trans);
+
        /*
         * Ensure we obey path->should_be_locked: if it's set, we can't unlock
         * and re-traverse the path without a transaction restart:
@@ -2830,18 +2833,35 @@ void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size)
        return p;
 }
 
-static noinline void bch2_trans_reset_srcu_lock(struct btree_trans *trans)
+static inline void check_srcu_held_too_long(struct btree_trans *trans)
 {
-       struct bch_fs *c = trans->c;
-       struct btree_path *path;
+       WARN(time_after(jiffies, trans->srcu_lock_time + HZ * 10),
+            "btree trans held srcu lock (delaying memory reclaim) by more than 10 seconds");
+}
 
-       trans_for_each_path(trans, path)
-               if (path->cached && !btree_node_locked(path, 0))
-                       path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_srcu_reset);
+void bch2_trans_srcu_unlock(struct btree_trans *trans)
+{
+       if (trans->srcu_held) {
+               struct bch_fs *c = trans->c;
+               struct btree_path *path;
 
-       srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
-       trans->srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
-       trans->srcu_lock_time   = jiffies;
+               trans_for_each_path(trans, path)
+                       if (path->cached && !btree_node_locked(path, 0))
+                               path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_srcu_reset);
+
+               check_srcu_held_too_long(trans);
+               srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
+               trans->srcu_held = false;
+       }
+}
+
+void bch2_trans_srcu_lock(struct btree_trans *trans)
+{
+       if (!trans->srcu_held) {
+               trans->srcu_idx = srcu_read_lock(&trans->c->btree_trans_barrier);
+               trans->srcu_lock_time   = jiffies;
+               trans->srcu_held = true;
+       }
 }
 
 /**
@@ -2895,8 +2915,9 @@ u32 bch2_trans_begin(struct btree_trans *trans)
        }
        trans->last_begin_time = now;
 
-       if (unlikely(time_after(jiffies, trans->srcu_lock_time + msecs_to_jiffies(10))))
-               bch2_trans_reset_srcu_lock(trans);
+       if (unlikely(trans->srcu_held &&
+                    time_after(jiffies, trans->srcu_lock_time + msecs_to_jiffies(10))))
+               bch2_trans_srcu_unlock(trans);
 
        trans->last_begin_ip = _RET_IP_;
        if (trans->restarted) {
@@ -2983,8 +3004,9 @@ struct btree_trans *__bch2_trans_get(struct bch_fs *c, unsigned fn_idx)
                trans->wb_updates_size = s->wb_updates_size;
        }
 
-       trans->srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
+       trans->srcu_idx         = srcu_read_lock(&c->btree_trans_barrier);
        trans->srcu_lock_time   = jiffies;
+       trans->srcu_held        = true;
 
        if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
                struct btree_trans *pos;
@@ -3061,7 +3083,10 @@ void bch2_trans_put(struct btree_trans *trans)
 
        check_btree_paths_leaked(trans);
 
-       srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
+       if (trans->srcu_held) {
+               check_srcu_held_too_long(trans);
+               srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
+       }
 
        bch2_journal_preres_put(&c->journal, &trans->journal_preres);