Method Setattr

cmd/cql-fuse/node.go:154–201

Setattr modifies node metadata. This includes changing the size.

(
	ctx context.Context, req *fuse.SetattrRequest, resp *fuse.SetattrResponse,
)

// Setattr modifies node metadata. This includes changing the size.
func (n *Node) Setattr(
	ctx context.Context, req *fuse.SetattrRequest, resp *fuse.SetattrResponse,
) error {
	if !req.Valid.Size() {
		// We can exit early since only setting the size is implemented.
		return nil
	}

	if !n.isRegular() {
		// Setting the size is only available on regular files.
		return fuse.Errno(syscall.EINVAL)
	}

	if req.Size > maxSize {
		// Too big.
		return fuse.Errno(syscall.EFBIG)
	}

	n.mu.Lock()
	defer n.mu.Unlock()

	if req.Size == n.Size {
		// Nothing to do.
		return nil
	}

	// Store the current size in case we need to rollback.
	originalSize := n.Size

	// Wrap everything inside a transaction.
	err := client.ExecuteTx(ctx, n.cfs.db, nil /* txopts */, func(tx *sql.Tx) error {
		// Resize blocks as needed.
		if err := resizeBlocks(tx, n.ID, n.Size, req.Size); err != nil {
			return err
		}

		n.Size = req.Size
		return updateNode(tx, n)
	})

	if err != nil {
		// Reset our size.
		log.Print(err)
		n.Size = originalSize
		return err
	}
	return nil
}

// Lookup looks up a specific entry in the receiver,
// which must be a directory.  Lookup should return a Node