bcachefs: Plumb btree_trans through btree cache code

Soon, __bch2_btree_node_write() is going to require a btree_trans: zoned
device support is going to require a new allocation for every btree node
write. This is a bit of prep work.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_cache.c

@@ -561,8 +561,9 @@ static struct btree *btree_node_cannibalize(struct bch_fs *c)
 	}
 }
 
-struct btree *bch2_btree_node_mem_alloc(struct bch_fs *c, bool pcpu_read_locks)
+struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_read_locks)
 {
+	struct bch_fs *c = trans->c;
 	struct btree_cache *bc = &c->btree_cache;
 	struct list_head *freed = pcpu_read_locks
 		? &bc->freed_pcpu
@@ -673,8 +674,7 @@ struct btree *bch2_btree_node_mem_alloc(struct bch_fs *c, bool pcpu_read_locks)
 }
 
 /* Slowpath, don't want it inlined into btree_iter_traverse() */
-static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
-				struct btree_trans *trans,
+static noinline struct btree *bch2_btree_node_fill(struct btree_trans *trans,
 				struct btree_path *path,
 				const struct bkey_i *k,
 				enum btree_id btree_id,
@@ -682,6 +682,7 @@ static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
 				enum six_lock_type lock_type,
 				bool sync)
 {
+	struct bch_fs *c = trans->c;
 	struct btree_cache *bc = &c->btree_cache;
 	struct btree *b;
 	u32 seq;
@@ -691,14 +692,14 @@ static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
 	 * Parent node must be locked, else we could read in a btree node that's
 	 * been freed:
 	 */
-	if (trans && !bch2_btree_node_relock(trans, path, level + 1)) {
+	if (path && !bch2_btree_node_relock(trans, path, level + 1)) {
 		trace_and_count(c, trans_restart_relock_parent_for_fill, trans, _THIS_IP_, path);
 		return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_relock));
 	}
 
-	b = bch2_btree_node_mem_alloc(c, level != 0);
+	b = bch2_btree_node_mem_alloc(trans, level != 0);
 
-	if (trans && b == ERR_PTR(-ENOMEM)) {
+	if (b == ERR_PTR(-ENOMEM)) {
 		trans->memory_allocation_failure = true;
 		trace_and_count(c, trans_restart_memory_allocation_failure, trans, _THIS_IP_, path);
 		return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_mem_alloc_fail));
@@ -744,7 +745,7 @@ static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
 	if (!sync)
 		return NULL;
 
-	if (trans) {
+	if (path) {
 		int ret = bch2_trans_relock(trans) ?:
 			bch2_btree_path_relock_intent(trans, path);
 		if (ret) {
@@ -754,7 +755,7 @@ static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
 	}
 
 	if (!six_relock_type(&b->c.lock, lock_type, seq)) {
-		if (trans)
+		if (path)
 			trace_and_count(c, trans_restart_relock_after_fill, trans, _THIS_IP_, path);
 		return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_relock_after_fill));
 	}
@@ -820,7 +821,7 @@ static struct btree *__bch2_btree_node_get(struct btree_trans *trans, struct btr
 		 * else we could read in a btree node from disk that's been
 		 * freed:
 		 */
-		b = bch2_btree_node_fill(c, trans, path, k, path->btree_id,
+		b = bch2_btree_node_fill(trans, path, k, path->btree_id,
 					 level, lock_type, true);
 
 		/* We raced and found the btree node in the cache */
@@ -1029,7 +1030,7 @@ struct btree *bch2_btree_node_get_noiter(struct btree_trans *trans,
 		if (nofill)
 			goto out;
 
-		b = bch2_btree_node_fill(c, NULL, NULL, k, btree_id,
+		b = bch2_btree_node_fill(trans, NULL, k, btree_id,
 					 level, SIX_LOCK_read, true);
 
 		/* We raced and found the btree node in the cache */
@@ -1089,12 +1090,12 @@ struct btree *bch2_btree_node_get_noiter(struct btree_trans *trans,
 	return b;
 }
 
-int bch2_btree_node_prefetch(struct bch_fs *c,
-			     struct btree_trans *trans,
+int bch2_btree_node_prefetch(struct btree_trans *trans,
 			     struct btree_path *path,
 			     const struct bkey_i *k,
 			     enum btree_id btree_id, unsigned level)
 {
+	struct bch_fs *c = trans->c;
 	struct btree_cache *bc = &c->btree_cache;
 	struct btree *b;
 
@@ -1105,7 +1106,7 @@ int bch2_btree_node_prefetch(struct bch_fs *c,
 	if (b)
 		return 0;
 
-	b = bch2_btree_node_fill(c, trans, path, k, btree_id,
+	b = bch2_btree_node_fill(trans, path, k, btree_id,
 				 level, SIX_LOCK_read, false);
 	return PTR_ERR_OR_ZERO(b);
 }

fs/bcachefs/btree_cache.h

@@ -21,7 +21,7 @@ void bch2_btree_cache_cannibalize_unlock(struct bch_fs *);
 int bch2_btree_cache_cannibalize_lock(struct bch_fs *, struct closure *);
 
 struct btree *__bch2_btree_node_mem_alloc(struct bch_fs *);
-struct btree *bch2_btree_node_mem_alloc(struct bch_fs *, bool);
+struct btree *bch2_btree_node_mem_alloc(struct btree_trans *, bool);
 
 struct btree *bch2_btree_node_get(struct btree_trans *, struct btree_path *,
 				  const struct bkey_i *, unsigned,
@@ -30,7 +30,7 @@ struct btree *bch2_btree_node_get(struct btree_trans *, struct btree_path *,
 struct btree *bch2_btree_node_get_noiter(struct btree_trans *, const struct bkey_i *,
 					 enum btree_id, unsigned, bool);
 
-int bch2_btree_node_prefetch(struct bch_fs *, struct btree_trans *, struct btree_path *,
+int bch2_btree_node_prefetch(struct btree_trans *, struct btree_path *,
 			     const struct bkey_i *, enum btree_id, unsigned);
 
 void bch2_btree_node_evict(struct btree_trans *, const struct bkey_i *);

fs/bcachefs/btree_io.c

@@ -1610,9 +1610,10 @@ void bch2_btree_node_read(struct bch_fs *c, struct btree *b,
 	}
 }
 
-int bch2_btree_root_read(struct bch_fs *c, enum btree_id id,
-			const struct bkey_i *k, unsigned level)
+static int __bch2_btree_root_read(struct btree_trans *trans, enum btree_id id,
+				  const struct bkey_i *k, unsigned level)
 {
+	struct bch_fs *c = trans->c;
 	struct closure cl;
 	struct btree *b;
 	int ret;
@@ -1624,7 +1625,7 @@ int bch2_btree_root_read(struct bch_fs *c, enum btree_id id,
 		closure_sync(&cl);
 	} while (ret);
 
-	b = bch2_btree_node_mem_alloc(c, level != 0);
+	b = bch2_btree_node_mem_alloc(trans, level != 0);
 	bch2_btree_cache_cannibalize_unlock(c);
 
 	BUG_ON(IS_ERR(b));
@@ -1655,6 +1656,13 @@ int bch2_btree_root_read(struct bch_fs *c, enum btree_id id,
 	return ret;
 }
 
+int bch2_btree_root_read(struct bch_fs *c, enum btree_id id,
+			const struct bkey_i *k, unsigned level)
+{
+	return bch2_trans_run(c, __bch2_btree_root_read(&trans, id, k, level));
+
+}
+
 void bch2_btree_complete_write(struct bch_fs *c, struct btree *b,
 			      struct btree_write *w)
 {

fs/bcachefs/btree_iter.c

@@ -815,7 +815,7 @@ static int btree_path_prefetch(struct btree_trans *trans, struct btree_path *pat
 			break;
 
 		bch2_bkey_buf_unpack(&tmp, c, l->b, k);
-		ret = bch2_btree_node_prefetch(c, trans, path, tmp.k, path->btree_id,
+		ret = bch2_btree_node_prefetch(trans, path, tmp.k, path->btree_id,
 					       path->level - 1);
 	}
 
@@ -850,7 +850,7 @@ static int btree_path_prefetch_j(struct btree_trans *trans, struct btree_path *p
 			break;
 
 		bch2_bkey_buf_reassemble(&tmp, c, k);
-		ret = bch2_btree_node_prefetch(c, trans, path, tmp.k, path->btree_id,
+		ret = bch2_btree_node_prefetch(trans, path, tmp.k, path->btree_id,
 					       path->level - 1);
 	}
 

fs/bcachefs/btree_update_interior.c

@@ -300,7 +300,7 @@ static struct btree *__bch2_btree_node_alloc(struct btree_trans *trans,
 	bch2_open_bucket_get(c, wp, &ob);
 	bch2_alloc_sectors_done(c, wp);
 mem_alloc:
-	b = bch2_btree_node_mem_alloc(c, interior_node);
+	b = bch2_btree_node_mem_alloc(trans, interior_node);
 	six_unlock_write(&b->c.lock);
 	six_unlock_intent(&b->c.lock);
 
@@ -2261,7 +2261,7 @@ int bch2_btree_node_update_key(struct btree_trans *trans, struct btree_iter *ite
 				return ret;
 		}
 
-		new_hash = bch2_btree_node_mem_alloc(c, false);
+		new_hash = bch2_btree_node_mem_alloc(trans, false);
 	}
 
 	path->intent_ref++;
@@ -2324,8 +2324,9 @@ void bch2_btree_set_root_for_read(struct bch_fs *c, struct btree *b)
 	bch2_btree_set_root_inmem(c, b);
 }
 
-void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
+static int __bch2_btree_root_alloc(struct btree_trans *trans, enum btree_id id)
 {
+	struct bch_fs *c = trans->c;
 	struct closure cl;
 	struct btree *b;
 	int ret;
@@ -2337,7 +2338,7 @@ void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
 		closure_sync(&cl);
 	} while (ret);
 
-	b = bch2_btree_node_mem_alloc(c, false);
+	b = bch2_btree_node_mem_alloc(trans, false);
 	bch2_btree_cache_cannibalize_unlock(c);
 
 	set_btree_node_fake(b);
@@ -2366,6 +2367,12 @@ void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
 
 	six_unlock_write(&b->c.lock);
 	six_unlock_intent(&b->c.lock);
+	return 0;
+}
+
+void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
+{
+	bch2_trans_run(c, __bch2_btree_root_alloc(&trans, id));
 }
 
 void bch2_btree_updates_to_text(struct printbuf *out, struct bch_fs *c)