tree 5532c49bb9b9b2f9f30582bc65299623364d92dd
parent fad525c0fcb4595d515ca32e8a2553caf95083b4
author William A. Kennington III <wak@google.com> 1713341127 -0700
committer William A. Kennington III <wak@google.com> 1713494469 -0700

ethernet_interface: Write an update marker to tmpfs

Currently, many BMC systems use JFFS2 as a filesystem for their RWFS.
JFFS2 doesn't support sub-second timestamps, and we sometimes have
instances of configuration writes happening within the same second
around a networkd reload. The second write is then ignored upon the next
networkd reload as the timestamp of the file hasn't changed!

Therefore, we leverage tmpfs which has higher precision timestamps as a
mechanism to guarantee networkd sees our updates without making extra
changes to networkd or writes to the RWFS.

Tested: Verified that during a gateway set operation (or any other
property write) the updated file is set with microsecond granularity.
Also verified that subsequent updates change the timestamp and it's set
right before networkd reloads for MAC updates.

Change-Id: Ibfd0463166223d0e4a6f7205d780f4de8590a0c1
Signed-off-by: William A. Kennington III <wak@google.com>