From: Cykang <[email protected]> According to the SCSI-3 Persistent Reservations specification, when a self-preemption is performed with a key that does not currently hold an active reservation, the operation should be treated as an unregister and should not fail.
The current code in do_mpath_persistent_reserve_out() does not check whether the preempting key has a reservation before invoking the self-preemption path. It unconditionally calls preempt_self() and re-registers the key on the local paths, even when the key has no reservation. This violates the SCSI-3 PR spec and can lead to incorrect reservation states. This patch moves the self-preemption check inside the conditional block so that it only executes when the key matches, but does not bypass the general preemption path for keys without a reservation. With this change, the code will fall through to the common PR_OUT handling (e.g., MPATH_PROUT_RES_SA or CLEAR_SA) when the key is not reserved, allowing the storage target to properly process the operation as an unregister. Signed-off-by: Cykang <[email protected]> Signed-off-by: Benjamin Marzinski <[email protected]> --- libmpathpersist/mpath_persist_int.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/libmpathpersist/mpath_persist_int.c b/libmpathpersist/mpath_persist_int.c index 3091c5c2..6ca3b97d 100644 --- a/libmpathpersist/mpath_persist_int.c +++ b/libmpathpersist/mpath_persist_int.c @@ -841,6 +841,7 @@ int do_mpath_persistent_reserve_out(vector curmp, vector pathvec, int fd, bool unregistering, preempting_reservation = false; bool updated_prkey = false; bool failed_paths = false; + bool self_preempt_unreg = false; ret = mpath_get_map(curmp, fd, &mpp); if (ret != MPATH_PR_SUCCESS) @@ -961,13 +962,20 @@ int do_mpath_persistent_reserve_out(vector curmp, vector pathvec, int fd, rq_type, noisy); break; } + /* if we are preempting ourself */ + if (memcmp(paramp->sa_key, paramp->key, 8) == 0) { + ret = preempt_self(mpp, rq_servact, rq_scope, + rq_type, noisy, PREE_WORK_NONE); + break; + } + } else if (memcmp(paramp->sa_key, paramp->key, 8) == 0) { + /* + * We are self-preempting, but we don't hold the + * reservation. This will unregister the device + */ + self_preempt_unreg = true; } - /* if we are preempting ourself */ - if (memcmp(paramp->sa_key, paramp->key, 8) == 0) { - ret = preempt_self(mpp, rq_servact, rq_scope, rq_type, - noisy, PREE_WORK_NONE); - break; - } + /* fallthrough */ case MPATH_PROUT_RES_SA: case MPATH_PROUT_CLEAR_SA: { @@ -1018,6 +1026,8 @@ int do_mpath_persistent_reserve_out(vector curmp, vector pathvec, int fd, case MPATH_PROUT_PREE_AB_SA: if (preempting_reservation) update_prhold(mpp->alias, true); + else if (self_preempt_unreg) + update_prflag(mpp, 0); } return ret; } -- 2.46.1
