8641 "zpool clear" and "zinject" don't work on "spare" or "replacing" vdevs

illumos/illumos-gate@2ba5f978a4f9b02da9db1b8cdd9ea5498eb00ad9

https://www.illumos.org/issues/8641:
"zpool clear" and "zinject -d" can both operate on specific vdevs, either
leaf or interior. However, due to an oversight, neither works on a "spare"
or "replacing" vdev. For example:

sudo zpool create foo raidz1 c1t5000CCA000081D61d0 c1t5000CCA000186235d0 spare c1t5000CCA000094115d0
sudo zpool replace foo c1t5000CCA000186235d0 c1t5000CCA000094115d0
$ zpool status foo pool: foo
state: ONLINE
scan: resilvered 81.5K in 0h0m with 0 errors on Fri Sep 8 10:53:03 2017
config:

NAME                         STATE     READ WRITE CKSUM
        foo                          ONLINE       0     0     0
          raidz1-0                   ONLINE       0     0     0
            c1t5000CCA000081D61d0    ONLINE       0     0     0
            spare-1                  ONLINE       0     0     0
              c1t5000CCA000186235d0  ONLINE       0     0     0
              c1t5000CCA000094115d0  ONLINE       0     0     0
        spares
          c1t5000CCA000094115d0      INUSE     currently in use
$ sudo zinject -d spare-1 -A degrade foo
cannot find device 'spare-1' in pool 'foo'
$ sudo zpool clear foo spare-1
cannot clear errors for spare-1: no such device in pool

Even though there was nothing to clear, those commands shouldn't have
reported an error. by contrast, trying to clear "raidz1-0" works just fine:
$ sudo zpool clear foo raidz1-0

1 files changed, 6 insertions, 5 deletions

diff --git a/lib/libzfs/common/libzfs_pool.c b/lib/libzfs/common/libzfs_pool.c
index db03bd6c0317..578ffcaf1f6e 100644
--- a/lib/libzfs/common/libzfs_pool.c
+++ b/lib/libzfs/common/libzfs_pool.c
@@ -50,6 +50,7 @@
 #include "zfeature_common.h"
 
 static int read_efi_label(nvlist_t *, diskaddr_t *, boolean_t *);
+static boolean_t zpool_vdev_is_interior(const char *name);
 
 #define	BACKUP_SLICE	"s2"
 
@@ -2072,10 +2073,7 @@ vdev_to_nvlist_iter(nvlist_t *nv, nvlist_t *search, boolean_t *avail_spare,
 				break;
 			}
 
-			verify(strncmp(type, VDEV_TYPE_RAIDZ,
-			    strlen(VDEV_TYPE_RAIDZ)) == 0 ||
-			    strncmp(type, VDEV_TYPE_MIRROR,
-			    strlen(VDEV_TYPE_MIRROR)) == 0);
+			verify(zpool_vdev_is_interior(type));
 			verify(nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ID,
 			    &id) == 0);
 
@@ -2182,10 +2180,13 @@ zpool_find_vdev_by_physpath(zpool_handle_t *zhp, const char *ppath,
 /*
  * Determine if we have an "interior" top-level vdev (i.e mirror/raidz).
  */
-boolean_t
+static boolean_t
 zpool_vdev_is_interior(const char *name)
 {
 	if (strncmp(name, VDEV_TYPE_RAIDZ, strlen(VDEV_TYPE_RAIDZ)) == 0 ||
+	    strncmp(name, VDEV_TYPE_SPARE, strlen(VDEV_TYPE_SPARE)) == 0 ||
+	    strncmp(name,
+	    VDEV_TYPE_REPLACING, strlen(VDEV_TYPE_REPLACING)) == 0 ||
 	    strncmp(name, VDEV_TYPE_MIRROR, strlen(VDEV_TYPE_MIRROR)) == 0)
 		return (B_TRUE);
 	return (B_FALSE);