Now that we know that the system uses s390x IPL and the current re-IPL
target is from FCP, whenever we get a udev event that indicates a path
state changed, we have to figure out whether it affects the path that is
currently set as re-IPL target, or goes to the same volume (so we might
use it as alternative re-IPL path).
Add a new helper `chreipl-fcp-mpath-is-ipl-tgt` for this task.
Based on the information provided in
/sys/firmware/reipl/fcp/{device,wwpn,lun} it figures out whether the
current event subject has the same triplet <Dev-Bus-ID>:<WWPN>:<LUN> (in
T10 SCSI: I_T_L nexus), or whether one of its parts (in case of
dm-multipath) has.
If true, we know for sure, that we deal with an event affecting the
current re-IPL setting, and continue.
When accessing the re-IPL firmware information a lock is taken via the
`flock` utility (from util-linux). This is done so concurrent changes
from the toolset, that are added in a later commit, don't result in
inconsistent reads.
Reviewed-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
