tree e1422afea67211d2dc3b55626d7897df89860bc8
parent e6e570ae3c26c5fda4855522e8cf04644627295f
author Serge Bazanski <serge@monogon.tech> 1701345259 +0100
committer Serge Bazanski <serge@monogon.tech> 1701359280 +0000

metropolis/node/c/localstorage: make writes durable

With just a write() -> rename() we can end up with an empty file in case
of an outage. The write() needs to be followed by an fsync() to avoid
that.

Since all of our localstorage framework contains only rarely-written
'configuration' style files, we now add such an fsync() to every
write().

This should fix some flakes in tests and low-load clusters where eg. a
node can't read back its key material or persisted node roles after
reboot.

Change-Id: Iefae4f8bd68ee2972860a7c58326442c80d8aa8c
Reviewed-on: https://review.monogon.dev/c/monogon/+/2411
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>