# 게스트의 write() 가 virtqueue 에 실리기까지
# Question: 게스트 애플리케이션의 write() 는 virtqueue 에 실리기 전에 게스트의 어느 계층을 어떤 순서로 지나는가
direction: down
g0: "Guest Userspace" {
  n0: "PostgreSQL / Keycloak" {
    shape: rectangle
  }
}
g1: "Guest Kernel" {
  n1: "VFS" {
    shape: rectangle
  }
  n2: "ext4 / XFS" {
    shape: rectangle
  }
  n3: "Guest Page Cache" {
    shape: rectangle
  }
  n4: "Guest Block Layer" {
    shape: rectangle
  }
  n5: "/dev/vda" {
    shape: rectangle
  }
  n6: "virtio-blk Frontend" {
    shape: rectangle
  }
  n7: "virtqueue" {
    shape: queue
  }
}
g0.n0 -> g1.n1
g1.n1 -> g1.n2
g1.n2 -> g1.n3
g1.n3 -> g1.n4: "writeback"
g1.n4 -> g1.n5: "WRITE / FLUSH"
g1.n5 -> g1.n6
g1.n6 -> g1.n7: "Virtio block request"