This patchset builds on top of my previous libmpathpersist patchset,
("Improve mpathpersist's unavailable path handling") and add various
fixes and cleanups to multipath's persistent reservation handling.The issues handled by this patchset are: - Handling removal of keys from paths that were down when the multipath device was unregistered. - Changing how conflicts on key registration are handled. Instead of the current rollback method (which was broken anyways), libmpathpersist now retrys with REGISTER AND IGNORE, as long as the REGISTER command completed successfully down some of the paths. - Changing when the reservation key is set to fix corner cases on failure and registration while paths are coming up. - Retrying on conflicts in mpath_prout_common to fix corner cases when a path is coming up while a doing a reserve, preempt or clear. - Allowing registrations to succeed when there are retryable errors, if the paths are actually down. - Fixing the reservation key validation code I realize that a number of these fixes are dealing with races between libmpathperist and multipathd, which points to shortcomings with the current design of libmpathpersist. The code could likely be simpler and more robust if limpathpersist was a thin wrapper around commands to multipathd, which handled issuing the actual persistent reservation commands. However, we have customers that need persistent reservations working well on currently released versions of the mutipath-tools, and redesigning how the libmpathpersist library works is a much larger task, and even harder to backport. I'd like to know if people think that would be a worthwhile task for later, however. Benjamin Marzinski (14): limpathpersist: remove update_map_pr code for NULL pp libmpathpersist: move update_map_pr to multipathd multipathd: clean up update_map_pr and mpath_pr_event_handle libmpathpersist: clean up duplicate function declarations multipathd: wrap setting and unsetting prflag multipathd: unregister PR key when path is restored if necessary libmpathpersist: Fix-up reservation_key checking libmpathpersist: change how reservation conflicts are handled libmpathpersist: Clear prkey in multipathd before unregistering libmpathpersist: only clear the key if we are using the prkeys file libmpathpersist: Restore old reservation key on failure libmpatpersist: update reservation key before checking paths libmpathpersist: retry on conflicts in mpath_prout_common libmpathpersist: Don't always fail registrations for retryable errors libmpathpersist/libmpathpersist.version | 1 - libmpathpersist/mpath_persist_int.c | 363 +++++++++++++----------- libmpathpersist/mpath_persist_int.h | 2 - libmpathpersist/mpath_pr_ioctl.c | 12 +- libmultipath/structs.h | 2 + mpathpersist/main.c | 2 - multipathd/cli_handlers.c | 11 +- multipathd/main.c | 132 +++++++-- multipathd/main.h | 2 + 9 files changed, 311 insertions(+), 216 deletions(-) -- 2.48.1
