2 files changed, 154 insertions, 14 deletions

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 189b8801c62d..3f85182e4b87 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -547,7 +547,13 @@ static int btrfs_delayed_item_reserve_metadata(struct btrfs_trans_handle *trans,
 		trace_btrfs_space_reservation(fs_info, "delayed_item",
 					      item->key.objectid,
 					      num_bytes, 1);
-		item->bytes_reserved = num_bytes;
+		/*
+		 * For insertions we track reserved metadata space by accounting
+		 * for the number of leaves that will be used, based on the delayed
+		 * node's index_items_size field.
+		 */
+		if (item->ins_or_del == BTRFS_DELAYED_DELETION_ITEM)
+			item->bytes_reserved = num_bytes;
 	}
 
 	return ret;
@@ -573,6 +579,21 @@ static void btrfs_delayed_item_release_metadata(struct btrfs_root *root,
 	btrfs_block_rsv_release(fs_info, rsv, item->bytes_reserved, NULL);
 }
 
+static void btrfs_delayed_item_release_leaves(struct btrfs_delayed_node *node,
+					      unsigned int num_leaves)
+{
+	struct btrfs_fs_info *fs_info = node->root->fs_info;
+	const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, num_leaves);
+
+	/* There are no space reservations during log replay, bail out. */
+	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
+		return;
+
+	trace_btrfs_space_reservation(fs_info, "delayed_item", node->inode_id,
+				      bytes, 0);
+	btrfs_block_rsv_release(fs_info, &fs_info->delayed_block_rsv, bytes, NULL);
+}
+
 static int btrfs_delayed_inode_reserve_metadata(
 					struct btrfs_trans_handle *trans,
 					struct btrfs_root *root,
@@ -660,15 +681,27 @@ static int btrfs_insert_delayed_item(struct btrfs_trans_handle *trans,
 				     struct btrfs_path *path,
 				     struct btrfs_delayed_item *first_item)
 {
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_delayed_node *node = first_item->delayed_node;
 	LIST_HEAD(item_list);
 	struct btrfs_delayed_item *curr;
 	struct btrfs_delayed_item *next;
-	const int max_size = BTRFS_LEAF_DATA_SIZE(root->fs_info);
+	const int max_size = BTRFS_LEAF_DATA_SIZE(fs_info);
 	struct btrfs_item_batch batch;
 	int total_size;
 	char *ins_data = NULL;
 	int ret;
 
+	lockdep_assert_held(&node->mutex);
+
+	/*
+	 * For delayed items to insert, we track reserved metadata bytes based
+	 * on the number of leaves that we will use.
+	 * See btrfs_insert_delayed_dir_index() and
+	 * btrfs_delayed_item_reserve_metadata()).
+	 */
+	ASSERT(first_item->bytes_reserved == 0);
+
 	list_add_tail(&first_item->tree_list, &item_list);
 	batch.total_data_size = first_item->data_len;
 	batch.nr = 1;
@@ -682,6 +715,8 @@ static int btrfs_insert_delayed_item(struct btrfs_trans_handle *trans,
 		if (!next)
 			break;
 
+		ASSERT(next->bytes_reserved == 0);
+
 		next_size = next->data_len + sizeof(struct btrfs_item);
 		if (total_size + next_size > max_size)
 			break;
@@ -738,9 +773,31 @@ static int btrfs_insert_delayed_item(struct btrfs_trans_handle *trans,
 	 */
 	btrfs_release_path(path);
 
+	ASSERT(node->index_item_leaves > 0);
+
+	if (next) {
+		/*
+		 * We inserted one batch of items into a leaf a there are more
+		 * items to flush in a future batch, now release one unit of
+		 * metadata space from the delayed block reserve, corresponding
+		 * the leaf we just flushed to.
+		 */
+		btrfs_delayed_item_release_leaves(node, 1);
+		node->index_item_leaves--;
+	} else {
+		/*
+		 * There are no more items to insert. We can have a number of
+		 * reserved leaves > 1 here - this happens when many dir index
+		 * items are added and then removed before they are flushed (file
+		 * names with a very short life, never span a transaction). So
+		 * release all remaining leaves.
+		 */
+		btrfs_delayed_item_release_leaves(node, node->index_item_leaves);
+		node->index_item_leaves = 0;
+	}
+
 	list_for_each_entry_safe(curr, next, &item_list, tree_list) {
 		list_del(&curr->tree_list);
-		btrfs_delayed_item_release_metadata(root, curr);
 		btrfs_release_delayed_item(curr);
 	}
 out:
@@ -1341,9 +1398,13 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
 				   struct btrfs_disk_key *disk_key, u8 type,
 				   u64 index)
 {
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	const unsigned int leaf_data_size = BTRFS_LEAF_DATA_SIZE(fs_info);
 	struct btrfs_delayed_node *delayed_node;
 	struct btrfs_delayed_item *delayed_item;
 	struct btrfs_dir_item *dir_item;
+	bool reserve_leaf_space;
+	u32 data_len;
 	int ret;
 
 	delayed_node = btrfs_get_or_create_delayed_node(dir);
@@ -1369,17 +1430,51 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
 	btrfs_set_stack_dir_type(dir_item, type);
 	memcpy((char *)(dir_item + 1), name, name_len);
 
-	ret = btrfs_delayed_item_reserve_metadata(trans, dir->root, delayed_item);
-	/*
-	 * Space was reserved for a dir index item insertion when we started the
-	 * transaction, so getting a failure here should be impossible.
-	 */
-	if (WARN_ON(ret)) {
-		btrfs_release_delayed_item(delayed_item);
-		goto release_node;
-	}
+	data_len = delayed_item->data_len + sizeof(struct btrfs_item);
 
 	mutex_lock(&delayed_node->mutex);
+
+	if (delayed_node->index_item_leaves == 0 ||
+	    delayed_node->curr_index_batch_size + data_len > leaf_data_size) {
+		delayed_node->curr_index_batch_size = data_len;
+		reserve_leaf_space = true;
+	} else {
+		delayed_node->curr_index_batch_size += data_len;
+		reserve_leaf_space = false;
+	}
+
+	if (reserve_leaf_space) {
+		ret = btrfs_delayed_item_reserve_metadata(trans, dir->root,
+							  delayed_item);
+		/*
+		 * Space was reserved for a dir index item insertion when we
+		 * started the transaction, so getting a failure here should be
+		 * impossible.
+		 */
+		if (WARN_ON(ret)) {
+			mutex_unlock(&delayed_node->mutex);
+			btrfs_release_delayed_item(delayed_item);
+			goto release_node;
+		}
+
+		delayed_node->index_item_leaves++;
+	} else if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
+		const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
+
+		/*
+		 * Adding the new dir index item does not require touching another
+		 * leaf, so we can release 1 unit of metadata that was previously
+		 * reserved when starting the transaction. This applies only to
+		 * the case where we had a transaction start and excludes the
+		 * transaction join case (when replaying log trees).
+		 */
+		trace_btrfs_space_reservation(fs_info, "transaction",
+					      trans->transid, bytes, 0);
+		btrfs_block_rsv_release(fs_info, trans->block_rsv, bytes, NULL);
+		ASSERT(trans->bytes_reserved >= bytes);
+		trans->bytes_reserved -= bytes;
+	}
+
 	ret = __btrfs_add_delayed_item(delayed_node, delayed_item);
 	if (unlikely(ret)) {
 		btrfs_err(trans->fs_info,
@@ -1408,8 +1503,37 @@ static int btrfs_delete_delayed_insertion_item(struct btrfs_fs_info *fs_info,
 		return 1;
 	}
 
-	btrfs_delayed_item_release_metadata(node->root, item);
+	/*
+	 * For delayed items to insert, we track reserved metadata bytes based
+	 * on the number of leaves that we will use.
+	 * See btrfs_insert_delayed_dir_index() and
+	 * btrfs_delayed_item_reserve_metadata()).
+	 */
+	ASSERT(item->bytes_reserved == 0);
+	ASSERT(node->index_item_leaves > 0);
+
+	/*
+	 * If there's only one leaf reserved, we can decrement this item from the
+	 * current batch, otherwise we can not because we don't know which leaf
+	 * it belongs to. With the current limit on delayed items, we rarely
+	 * accumulate enough dir index items to fill more than one leaf (even
+	 * when using a leaf size of 4K).
+	 */
+	if (node->index_item_leaves == 1) {
+		const u32 data_len = item->data_len + sizeof(struct btrfs_item);
+
+		ASSERT(node->curr_index_batch_size >= data_len);
+		node->curr_index_batch_size -= data_len;
+	}
+
 	btrfs_release_delayed_item(item);
+
+	/* If we now have no more dir index items, we can release all leaves. */
+	if (RB_EMPTY_ROOT(&node->ins_root.rb_root)) {
+		btrfs_delayed_item_release_leaves(node, node->index_item_leaves);
+		node->index_item_leaves = 0;
+	}
+
 	mutex_unlock(&node->mutex);
 	return 0;
 }
@@ -1825,12 +1949,17 @@ static void __btrfs_kill_delayed_node(struct btrfs_delayed_node *delayed_node)
 	mutex_lock(&delayed_node->mutex);
 	curr_item = __btrfs_first_delayed_insertion_item(delayed_node);
 	while (curr_item) {
-		btrfs_delayed_item_release_metadata(root, curr_item);
 		prev_item = curr_item;
 		curr_item = __btrfs_next_delayed_item(prev_item);
 		btrfs_release_delayed_item(prev_item);
 	}
 
+	if (delayed_node->index_item_leaves > 0) {
+		btrfs_delayed_item_release_leaves(delayed_node,
+					  delayed_node->index_item_leaves);
+		delayed_node->index_item_leaves = 0;
+	}
+
 	curr_item = __btrfs_first_delayed_deletion_item(delayed_node);
 	while (curr_item) {
 		btrfs_delayed_item_release_metadata(root, curr_item);
diff --git a/fs/btrfs/delayed-inode.h b/fs/btrfs/delayed-inode.h
index b2412160c5bc..9795dc295a18 100644
--- a/fs/btrfs/delayed-inode.h
+++ b/fs/btrfs/delayed-inode.h
@@ -58,6 +58,17 @@ struct btrfs_delayed_node {
 	u64 index_cnt;
 	unsigned long flags;
 	int count;
+	/*
+	 * The size of the next batch of dir index items to insert (if this
+	 * node is from a directory inode). Protected by @mutex.
+	 */
+	u32 curr_index_batch_size;
+	/*
+	 * Number of leaves reserved for inserting dir index items (if this
+	 * node belongs to a directory inode). This may be larger then the
+	 * actual number of leaves we end up using. Protected by @mutex.
+	 */
+	u32 index_item_leaves;
 };
 
 struct btrfs_delayed_item {