[dm-devel] [PATCH v2 44/54] libmultipath: adopt_paths(): don't bail out on single path failure

[mwilck at suse.com]

From: Martin Wilck <mwilck at suse.com>

If pathinfo fails for one path to be adopted, we currently
fail the entire function. This may cause ev_add_path() for a valid
path to fail because some other path is broken. Fix it by just
skipping paths that don't look healthy.

adopt_paths() may now succeed even if some paths couldn't be
added (e.g. because of pathinfo() failure). If this happens while we are
trying to add a specific path, we need to check after successful call to
adopt_paths() if that specific path had been actually added, and fail in the
caller otherwise.

Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 libmultipath/structs_vec.c | 17 +++++++++++------
 multipathd/main.c          |  3 ++-
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/libmultipath/structs_vec.c b/libmultipath/structs_vec.c
index b1f83c6..fb225f1 100644
--- a/libmultipath/structs_vec.c
+++ b/libmultipath/structs_vec.c
@@ -75,16 +75,20 @@ int adopt_paths(vector pathvec, struct multipath *mpp)
 			if (!mpp->paths && !(mpp->paths = vector_alloc()))
 				return 1;
 
-			if (!find_path_by_devt(mpp->paths, pp->dev_t) &&
-			    store_path(mpp->paths, pp))
-					return 1;
 			conf = get_multipath_config();
 			pthread_cleanup_push(put_multipath_config, conf);
 			ret = pathinfo(pp, conf,
 				       DI_PRIO | DI_CHECKER);
 			pthread_cleanup_pop(1);
-			if (ret)
-				return 1;
+			if (ret) {
+				condlog(3, "%s: pathinfo failed for %s",
+					__func__, pp->dev);
+				continue;
+			}
+
+			if (!find_path_by_devt(mpp->paths, pp->dev_t) &&
+			    store_path(mpp->paths, pp))
+					return 1;
 		}
 	}
 	return 0;
@@ -456,7 +460,8 @@ struct multipath *add_map_with_path(struct vectors *vecs, struct path *pp,
 		goto out;
 	mpp->size = pp->size;
 
-	if (adopt_paths(vecs->pathvec, mpp))
+	if (adopt_paths(vecs->pathvec, mpp) ||
+	    find_slot(vecs->pathvec, pp) == -1)
 		goto out;
 
 	if (add_vec) {
diff --git a/multipathd/main.c b/multipathd/main.c
index 61929a7..5902e7c 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -956,7 +956,8 @@ rescan:
 	if (mpp) {
 		condlog(4,"%s: adopting all paths for path %s",
 			mpp->alias, pp->dev);
-		if (adopt_paths(vecs->pathvec, mpp))
+		if (adopt_paths(vecs->pathvec, mpp) ||
+		    find_slot(vecs->pathvec, pp) == -1)
 			goto fail; /* leave path added to pathvec */
 
 		verify_paths(mpp, vecs);
-- 
2.28.0