tree a7232b5be01db53060685a7c2f994f6685f63bdd
parent a250ce240f245df594570a5e25398680d403af67
author NeilBrown <neilb@suse.com> 1492656005 +1000
committer Jes Sorensen <jsorensen@fb.com> 1492707447 -0400

systemd/mdadm-last-resort: use ConditionPathExists instead of Conflicts

Commit cec72c071bbe ("systemd/mdadm-last-resort: add Conflicts to .service file.")

added a 'Conflicts' directive to the mdadm-last-resort@.service file in
the hope that this would make sure the service didn't run after the device
was active, even if the timer managed to get started, which is possible in
race conditions.

This seemed to work is testing, but it isn't clear why, and it is known
to cause problems.
If systemd happens to know that the mentioned device is a dependency of a
mount point, the Conflicts can unmount that mountpoint, which is certainly
not wanted.

So remove the "Conflicts" and instead use
 ConditionPathExists=!/sys/devices/virtual/block/%i/md/sync_action

The "sync_action" file exists for any array which requires last-resort
handling, and only appears when the array is activated.  So it is safe
to rely on it to determine if the last-resort is really needed.

Fixes: cec72c071bbe ("systemd/mdadm-last-resort: add Conflicts to .service file.")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>