From: Amir Shehata <ashehata@whamcloud.com>
Date: Thu, 6 May 2021 06:02:22 +0000 (-0700)
Subject: LU-14668 lnet: don't delete peer created by Lustre
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=40e3dc586e316b2e8caff44d6dab2fd38b1ebc4c;p=fs%2Flustre-release.git

LU-14668 lnet: don't delete peer created by Lustre

Peers created by Lustre have their primary NIDs locked.
If that peer is deleted, it'll confuse lustre. So when manually
deleting a peer using:
   lnetctl peer del --prim_nid ...
We must continue to preserve the primary NID. Therefore we delete
all the constituent NIDs, but keep the primary NID. We then
flag the peer for rediscovery.

Lustre-change: https://review.whamcloud.com/43565
Lustre-commit: TBD (83f66616e303039974e7ed6ec07140dcc17f0cea)

Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I34eef9b0049435a01fde87dc8263dd50f631c551
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/50117
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Cyril Bordage <cbordage@whamcloud.com>
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
---

diff --git a/lnet/lnet/peer.c b/lnet/lnet/peer.c
index 0b28060..4ed553c 100644
--- a/lnet/lnet/peer.c
+++ b/lnet/lnet/peer.c
@@ -1836,6 +1836,40 @@ int lnet_user_add_peer_ni(lnet_nid_t prim_nid, lnet_nid_t nid, bool mr)
 	return lnet_add_peer_ni(prim_nid, nid, mr, LNET_PEER_CONFIGURED);
 }
 
+static int
+lnet_reset_peer(struct lnet_peer *lp)
+{
+	struct lnet_peer_net *lpn, *lpntmp;
+	struct lnet_peer_ni *lpni, *lpnitmp;
+	unsigned int flags;
+	int rc;
+
+	lnet_peer_cancel_discovery(lp);
+
+	flags = LNET_PEER_CONFIGURED;
+	if (lp->lp_state & LNET_PEER_MULTI_RAIL)
+		flags |= LNET_PEER_MULTI_RAIL;
+
+	list_for_each_entry_safe(lpn, lpntmp, &lp->lp_peer_nets, lpn_peer_nets) {
+		list_for_each_entry_safe(lpni, lpnitmp, &lpn->lpn_peer_nis,
+					 lpni_peer_nis) {
+			if (lpni->lpni_nid == lp->lp_primary_nid)
+				continue;
+
+			rc = lnet_peer_del_nid(lp, lpni->lpni_nid, flags);
+			if (rc) {
+				CERROR("Failed to delete %s from peer %s\n",
+				       libcfs_nid2str(lpni->lpni_nid),
+				       libcfs_nid2str(lp->lp_primary_nid));
+			}
+		}
+	}
+
+	/* mark it for discovery the next time we use it */
+	lp->lp_state &= ~LNET_PEER_NIDS_UPTODATE;
+	return 0;
+}
+
 /*
  * Implementation of IOC_LIBCFS_DEL_PEER_NI.
  *
@@ -1879,8 +1913,15 @@ lnet_del_peer_ni(lnet_nid_t prim_nid, lnet_nid_t nid)
 	}
 	lnet_net_unlock(LNET_LOCK_EX);
 
-	if (nid == LNET_NID_ANY || nid == lp->lp_primary_nid)
-		return lnet_peer_del(lp);
+	if (nid == LNET_NID_ANY || nid == lp->lp_primary_nid) {
+		if (lp->lp_state & LNET_PEER_LOCK_PRIMARY) {
+			CERROR("peer %s created by Lustre. Must preserve primary NID, but will remove other NIDs\n",
+			       libcfs_nid2str(lp->lp_primary_nid));
+			return lnet_reset_peer(lp);
+		} else {
+			return lnet_peer_del(lp);
+		}
+	}
 
 	flags = LNET_PEER_CONFIGURED;
 	if (lp->lp_state & LNET_PEER_MULTI_RAIL)