bcachefs: btree_node_unlock() can now drop write locks

Prep work for reworking btree node locking during interior btree
updates.

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

diff --git a/fs/bcachefs/btree_locking.h b/fs/bcachefs/btree_locking.h
index fb3d04ddcb409e86a4827e1da5af5451b77aa78a..80f1770781010ebaa542e50896217e67ad31ae05 100644 (file)
--- a/fs/bcachefs/btree_locking.h
+++ b/fs/bcachefs/btree_locking.h
@@ -75,13 +75,6 @@ static inline void mark_btree_node_locked_noreset(struct btree_path *path,
        path->nodes_locked |= (type + 1) << (level << 1);
 }
 
-static inline void mark_btree_node_unlocked(struct btree_path *path,
-                                           unsigned level)
-{
-       EBUG_ON(btree_node_write_locked(path, level));
-       mark_btree_node_locked_noreset(path, level, BTREE_NODE_UNLOCKED);
-}
-
 static inline void mark_btree_node_locked(struct btree_trans *trans,
                                          struct btree_path *path,
                                          unsigned level,
@@ -124,19 +117,25 @@ static void btree_trans_lock_hold_time_update(struct btree_trans *trans,
 
 /* unlock: */
 
+void bch2_btree_node_unlock_write(struct btree_trans *,
+                       struct btree_path *, struct btree *);
+
 static inline void btree_node_unlock(struct btree_trans *trans,
                                     struct btree_path *path, unsigned level)
 {
        int lock_type = btree_node_locked_type(path, level);
 
        EBUG_ON(level >= BTREE_MAX_DEPTH);
-       EBUG_ON(lock_type == BTREE_NODE_WRITE_LOCKED);
 
        if (lock_type != BTREE_NODE_UNLOCKED) {
+               if (unlikely(lock_type == BTREE_NODE_WRITE_LOCKED)) {
+                       bch2_btree_node_unlock_write(trans, path, path->l[level].b);
+                       lock_type = BTREE_NODE_INTENT_LOCKED;
+               }
                six_unlock_type(&path->l[level].b->c.lock, lock_type);
                btree_trans_lock_hold_time_update(trans, path, level);
+               mark_btree_node_locked_noreset(path, level, BTREE_NODE_UNLOCKED);
        }
-       mark_btree_node_unlocked(path, level);
 }
 
 static inline int btree_path_lowest_level_locked(struct btree_path *path)
@@ -165,11 +164,13 @@ static inline void __bch2_btree_path_unlock(struct btree_trans *trans,
 static inline void
 __bch2_btree_node_unlock_write(struct btree_trans *trans, struct btree *b)
 {
-       struct btree_path *linked;
-       unsigned i;
+       if (!b->c.lock.write_lock_recurse) {
+               struct btree_path *linked;
+               unsigned i;
 
-       trans_for_each_path_with_node(trans, b, linked, i)
-               linked->l[b->c.level].lock_seq++;
+               trans_for_each_path_with_node(trans, b, linked, i)
+                       linked->l[b->c.level].lock_seq++;
+       }
 
        six_unlock_write(&b->c.lock);
 }
@@ -186,9 +187,6 @@ bch2_btree_node_unlock_write_inlined(struct btree_trans *trans, struct btree_pat
        __bch2_btree_node_unlock_write(trans, b);
 }
 
-void bch2_btree_node_unlock_write(struct btree_trans *,
-                       struct btree_path *, struct btree *);
-
 int bch2_six_check_for_deadlock(struct six_lock *lock, void *p);
 
 /* lock: */