When creating a new mount unit after an event on /proc/self/mountinfo,
check the mount options as well as the fstype to determine if this is a
remote mount that requires network access.
This is an attempt to add it the remote-fs dependencies to a mount unit
if the options change, like when the utab options are picked up after
mountinfo has already been processed. It just adds the remote-fs
dependencies, leaving the local-fs ones in place.
With this change I always get mount units with proper remote-fs
dependencies when mounted with the _netdev option.
Parsing the mount table with libmount races against the mount command,
which will handle the actual mounting before updating utab. This means
the poll event on /proc/self/mountinfo can kick of a reparse in systemd
before the utab information is available.
This change adds in an additional event source using inotify to watch
for changes to utab. It only watches for IN_MOVED_TO events, matching
libmount behavior of always overwriting this file using rename(2).
This does add a second pass through the mount table parsing when utab is
updated.