vsftpd returns 226(successful) even when it fails to write data on remote nfs file system with quota

Issue

• In the following situation, vsftpd returns 226(successful) to ftp client even when it fails to write data due to quota limit set on remote(nfs) file system.

  host1 host2
  +------------------+ +----------------+ put
  | nfs file system | | with quota | mount with async | and ftp server | ---->
  +------------------+ +----------------+ 226

• nfs file system with quota is exported on host1

• host2 mounts the remote(host1) nfs file system with async option to a certain mount point
• vsftpd runs on host2 and it can access mount point
• ftp client puts a (large) file via ftp to the mount point on host2 which will be transferred to and saved on host1
• vsftpd returns "226 Transfer complete." to ftp client even when it fails to write data to remote nfs file system due to quota limit set on host1