Bug Report

Context

Several scripts use flock to lock various files and "prevent race conditions

https://linux.die.net/man/2/flock
Notes
flock() does not lock files over NFS. Use fcntl(2) instead: that does work over NFS, given a sufficiently recent version of Linux and a server which supports locking.

What is affected by this bug?

Ability to use NFS (and EFS)

When does this occur?

./setup.sh commands that use the binaries that use flock

How do we replicate the issue?

Mount NFS4.1 and use it to store the configs.

Behavior

+ docker run --rm -v /mnt/efs-us-west-2/config:/tmp/docker-mailserver -ti {tag} delmailuser {email}
Do you want to delete the mailbox as well (removing all mails) ? [Y/n] y
flock: 200: Bad file descriptor

FSTAB:
XXX:/ /mnt/efs-us-west-2 nfs4 nfsvers=4.1,rsize=1048576,wsize=1048576,hard,timeo=600,retrans=2,noresvport 0 0