zpool: Add slot power control, print power status

Add `zpool` flags to control the slot power to drives.  This assumes
your SAS or NVMe enclosure supports slot power control via sysfs.

The new `--power` flag is added to `zpool offline|online|clear`:

    zpool offline --power <pool> <device>    Turn off device slot power
    zpool online --power <pool> <device>     Turn on device slot power
    zpool clear --power <pool> [device]      Turn on device slot power

If the ZPOOL_AUTO_POWER_ON_SLOT env var is set, then the '--power'
option is automatically implied for `zpool online` and `zpool clear`
and does not need to be passed.

zpool status also gets a --power option to print the slot power status.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mart Frauenlob <AllKind@fastest.cc>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #15662

lib/libzfs/libzfs.abi

@@ -179,6 +179,7 @@
     <elf-symbol name='fletcher_4_native' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='fletcher_4_native_varsize' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='fletcher_init' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='fsleep' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='get_dataset_depth' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='get_system_hostid' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='getexecname' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
@@ -466,6 +467,7 @@
     <elf-symbol name='zpool_disable_datasets_os' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_disable_volume_os' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_discard_checkpoint' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='zpool_disk_wait' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_dump_ddt' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_enable_datasets' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_events_clear' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
@@ -497,6 +499,7 @@
     <elf-symbol name='zpool_get_userprop' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_get_vdev_prop' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_get_vdev_prop_value' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='zpool_getenv_int' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_history_unpack' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_import' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_import_props' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
@@ -567,6 +570,7 @@
     <elf-symbol name='zpool_vdev_remove_wanted' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_vdev_script_alloc_env' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_vdev_script_free_env' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='zpool_vdev_set_removed_state' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_vdev_split' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_wait' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_wait_status' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
@@ -1368,8 +1372,6 @@
     <qualified-type-def type-id='0897719a' const='yes' id='c4a7b189'/>
     <pointer-type-def type-id='c4a7b189' size-in-bits='64' id='36fca399'/>
     <qualified-type-def type-id='36fca399' restrict='yes' id='37e4897b'/>
-    <qualified-type-def type-id='a9c79a1f' const='yes' id='cd087e36'/>
-    <pointer-type-def type-id='cd087e36' size-in-bits='64' id='e05e8614'/>
     <qualified-type-def type-id='e05e8614' restrict='yes' id='0be2e71c'/>
     <pointer-type-def type-id='8037c762' size-in-bits='64' id='d74a6869'/>
     <qualified-type-def type-id='7292109c' restrict='yes' id='6942f6a4'/>
@@ -6426,6 +6428,12 @@
       <parameter type-id='9d774e0b' name='aux'/>
       <return type-id='95e97e5e'/>
     </function-decl>
+    <function-decl name='zpool_vdev_set_removed_state' mangled-name='zpool_vdev_set_removed_state' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_vdev_set_removed_state'>
+      <parameter type-id='4c81de99' name='zhp'/>
+      <parameter type-id='9c313c2d' name='guid'/>
+      <parameter type-id='9d774e0b' name='aux'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='zpool_vdev_attach' mangled-name='zpool_vdev_attach' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_vdev_attach'>
       <parameter type-id='4c81de99' name='zhp'/>
       <parameter type-id='80f4b756' name='old_disk'/>
@@ -7792,6 +7800,12 @@
     <qualified-type-def type-id='d33f11cb' restrict='yes' id='5c53ba29'/>
     <pointer-type-def type-id='ffa52b96' size-in-bits='64' id='76c8174b'/>
     <pointer-type-def type-id='f3d87113' size-in-bits='64' id='0d2a0670'/>
+    <function-decl name='zpool_label_disk' mangled-name='zpool_label_disk' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_label_disk'>
+      <parameter type-id='b0382bb3'/>
+      <parameter type-id='4c81de99'/>
+      <parameter type-id='80f4b756'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='zfs_version_kernel' mangled-name='zfs_version_kernel' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_version_kernel'>
       <return type-id='26a90f95'/>
     </function-decl>
@@ -7801,6 +7815,10 @@
     <function-decl name='libzfs_core_fini' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='48b5725f'/>
     </function-decl>
+    <function-decl name='zfs_get_underlying_path' mangled-name='zfs_get_underlying_path' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_get_underlying_path'>
+      <parameter type-id='80f4b756'/>
+      <return type-id='26a90f95'/>
+    </function-decl>
     <function-decl name='zpool_prop_unsupported' mangled-name='zpool_prop_unsupported' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_prop_unsupported'>
       <parameter type-id='80f4b756'/>
       <return type-id='c19b74c3'/>
@@ -7918,6 +7936,11 @@
       <parameter type-id='b59d7dce'/>
       <return type-id='95e97e5e'/>
     </function-decl>
+    <function-decl name='access' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='80f4b756'/>
+      <parameter type-id='95e97e5e'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='dup2' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
       <parameter type-id='95e97e5e'/>
@@ -8085,6 +8108,37 @@
       <parameter is-variadic='yes'/>
       <return type-id='95e97e5e'/>
     </function-decl>
+    <function-decl name='zpool_vdev_script_alloc_env' mangled-name='zpool_vdev_script_alloc_env' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_vdev_script_alloc_env'>
+      <parameter type-id='80f4b756' name='pool_name'/>
+      <parameter type-id='80f4b756' name='vdev_path'/>
+      <parameter type-id='80f4b756' name='vdev_upath'/>
+      <parameter type-id='80f4b756' name='vdev_enc_sysfs_path'/>
+      <parameter type-id='80f4b756' name='opt_key'/>
+      <parameter type-id='80f4b756' name='opt_val'/>
+      <return type-id='9b23c9ad'/>
+    </function-decl>
+    <function-decl name='zpool_vdev_script_free_env' mangled-name='zpool_vdev_script_free_env' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_vdev_script_free_env'>
+      <parameter type-id='9b23c9ad' name='env'/>
+      <return type-id='48b5725f'/>
+    </function-decl>
+    <function-decl name='zpool_prepare_disk' mangled-name='zpool_prepare_disk' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_prepare_disk'>
+      <parameter type-id='4c81de99' name='zhp'/>
+      <parameter type-id='5ce45b60' name='vdev_nv'/>
+      <parameter type-id='80f4b756' name='prepare_str'/>
+      <parameter type-id='c0563f85' name='lines'/>
+      <parameter type-id='7292109c' name='lines_cnt'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
+    <function-decl name='zpool_prepare_and_label_disk' mangled-name='zpool_prepare_and_label_disk' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_prepare_and_label_disk'>
+      <parameter type-id='b0382bb3' name='hdl'/>
+      <parameter type-id='4c81de99' name='zhp'/>
+      <parameter type-id='80f4b756' name='name'/>
+      <parameter type-id='5ce45b60' name='vdev_nv'/>
+      <parameter type-id='80f4b756' name='prepare_str'/>
+      <parameter type-id='c0563f85' name='lines'/>
+      <parameter type-id='7292109c' name='lines_cnt'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
   </abi-instr>
   <abi-instr address-size='64' path='lib/libzfs/os/linux/libzfs_mount_os.c' language='LANG_C99'>
     <pointer-type-def type-id='7359adad' size-in-bits='64' id='1d2c2b85'/>
@@ -8274,12 +8328,6 @@
       <parameter type-id='95e97e5e'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='zpool_label_disk' mangled-name='zpool_label_disk' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_label_disk'>
-      <parameter type-id='b0382bb3' name='hdl'/>
-      <parameter type-id='4c81de99' name='zhp'/>
-      <parameter type-id='80f4b756' name='name'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
   </abi-instr>
   <abi-instr address-size='64' path='lib/libzfs/os/linux/libzfs_util_os.c' language='LANG_C99'>
     <typedef-decl name='nfds_t' type-id='7359adad' id='555eef66'/>
@@ -8295,11 +8343,6 @@
       </data-member>
     </class-decl>
     <pointer-type-def type-id='b440e872' size-in-bits='64' id='3ac36db0'/>
-    <function-decl name='access' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='80f4b756'/>
-      <parameter type-id='95e97e5e'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='__poll_chk' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='3ac36db0'/>
       <parameter type-id='555eef66'/>
@@ -8384,10 +8427,6 @@
       <parameter type-id='80f4b756' name='dev_name'/>
       <return type-id='c19b74c3'/>
     </function-decl>
-    <function-decl name='zfs_get_underlying_path' mangled-name='zfs_get_underlying_path' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_get_underlying_path'>
-      <parameter type-id='80f4b756' name='dev_name'/>
-      <return type-id='26a90f95'/>
-    </function-decl>
     <function-decl name='is_mpath_whole_disk' mangled-name='is_mpath_whole_disk' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='is_mpath_whole_disk'>
       <parameter type-id='80f4b756' name='path'/>
       <return type-id='c19b74c3'/>
@@ -8523,6 +8562,10 @@
       <parameter type-id='b59d7dce' name='buflen'/>
       <return type-id='95e97e5e'/>
     </function-decl>
+    <function-decl name='zpool_disk_wait' mangled-name='zpool_disk_wait' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_disk_wait'>
+      <parameter type-id='80f4b756' name='path'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='update_vdev_config_dev_sysfs_path' mangled-name='update_vdev_config_dev_sysfs_path' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='update_vdev_config_dev_sysfs_path'>
       <parameter type-id='5ce45b60' name='nv'/>
       <parameter type-id='80f4b756' name='path'/>
@@ -8548,6 +8591,9 @@
       <parameter type-id='95e97e5e'/>
       <return type-id='95e97e5e'/>
     </function-decl>
+    <function-decl name='clearenv' visibility='default' binding='global' size-in-bits='64'>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='zfs_setproctitle_init' mangled-name='zfs_setproctitle_init' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_setproctitle_init'>
       <parameter type-id='95e97e5e' name='argc'/>
       <parameter type-id='9b23c9ad' name='argv'/>
@@ -8778,6 +8824,7 @@
     <array-type-def dimensions='1' type-id='853fd5dc' size-in-bits='32768' id='b505fc2f'>
       <subrange length='64' type-id='7359adad' id='b10be967'/>
     </array-type-def>
+    <type-decl name='float' size-in-bits='32' id='a6c45d85'/>
     <class-decl name='ddt_stat' size-in-bits='512' is-struct='yes' visibility='default' id='65242dfe'>
       <data-member access='public' layout-offset-in-bits='0'>
         <var-decl name='dds_blocks' type-id='9c313c2d' visibility='default'/>
@@ -8815,11 +8862,27 @@
     <pointer-type-def type-id='ec92d602' size-in-bits='64' id='932720f8'/>
     <qualified-type-def type-id='853fd5dc' const='yes' id='764c298c'/>
     <pointer-type-def type-id='764c298c' size-in-bits='64' id='dfe59052'/>
+    <qualified-type-def type-id='a9c79a1f' const='yes' id='cd087e36'/>
+    <pointer-type-def type-id='cd087e36' size-in-bits='64' id='e05e8614'/>
+    <function-decl name='nanosleep' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='e05e8614'/>
+      <parameter type-id='3d83ba87'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='zpool_dump_ddt' mangled-name='zpool_dump_ddt' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_dump_ddt'>
       <parameter type-id='dfe59052' name='dds_total'/>
       <parameter type-id='932720f8' name='ddh'/>
       <return type-id='48b5725f'/>
     </function-decl>
+    <function-decl name='fsleep' mangled-name='fsleep' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='fsleep'>
+      <parameter type-id='a6c45d85' name='sec'/>
+      <return type-id='48b5725f'/>
+    </function-decl>
+    <function-decl name='zpool_getenv_int' mangled-name='zpool_getenv_int' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_getenv_int'>
+      <parameter type-id='80f4b756' name='env'/>
+      <parameter type-id='95e97e5e' name='default_val'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
   </abi-instr>
   <abi-instr address-size='64' path='module/avl/avl.c' language='LANG_C99'>
     <function-decl name='avl_last' mangled-name='avl_last' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='avl_last'>

lib/libzfs/libzfs_pool.c

@@ -3036,6 +3036,9 @@ zpool_vdev_is_interior(const char *name)
 	return (B_FALSE);
 }
 
+/*
+ * Lookup the nvlist for a given vdev.
+ */
 nvlist_t *
 zpool_find_vdev(zpool_handle_t *zhp, const char *path, boolean_t *avail_spare,
     boolean_t *l2cache, boolean_t *log)
@@ -3043,6 +3046,7 @@ zpool_find_vdev(zpool_handle_t *zhp, const char *path, boolean_t *avail_spare,
 	char *end;
 	nvlist_t *nvroot, *search, *ret;
 	uint64_t guid;
+	boolean_t __avail_spare, __l2cache, __log;
 
 	search = fnvlist_alloc();
 
@@ -3058,6 +3062,18 @@ zpool_find_vdev(zpool_handle_t *zhp, const char *path, boolean_t *avail_spare,
 	nvroot = fnvlist_lookup_nvlist(zhp->zpool_config,
 	    ZPOOL_CONFIG_VDEV_TREE);
 
+	/*
+	 * User can pass NULL for avail_spare, l2cache, and log, but
+	 * we still need to provide variables to vdev_to_nvlist_iter(), so
+	 * just point them to junk variables here.
+	 */
+	if (!avail_spare)
+		avail_spare = &__avail_spare;
+	if (!l2cache)
+		l2cache = &__l2cache;
+	if (!log)
+		log = &__log;
+
 	*avail_spare = B_FALSE;
 	*l2cache = B_FALSE;
 	if (log != NULL)
@@ -3313,21 +3329,23 @@ zpool_vdev_fault(zpool_handle_t *zhp, uint64_t guid, vdev_aux_t aux)
 }
 
 /*
- * Mark the given vdev degraded.
+ * Generic set vdev state function
  */
-int
-zpool_vdev_degrade(zpool_handle_t *zhp, uint64_t guid, vdev_aux_t aux)
+static int
+zpool_vdev_set_state(zpool_handle_t *zhp, uint64_t guid, vdev_aux_t aux,
+    vdev_state_t state)
 {
 	zfs_cmd_t zc = {"\0"};
 	char errbuf[ERRBUFLEN];
 	libzfs_handle_t *hdl = zhp->zpool_hdl;
 
 	(void) snprintf(errbuf, sizeof (errbuf),
-	    dgettext(TEXT_DOMAIN, "cannot degrade %llu"), (u_longlong_t)guid);
+	    dgettext(TEXT_DOMAIN, "cannot set %s %llu"),
+	    zpool_state_to_name(state, aux), (u_longlong_t)guid);
 
 	(void) strlcpy(zc.zc_name, zhp->zpool_name, sizeof (zc.zc_name));
 	zc.zc_guid = guid;
-	zc.zc_cookie = VDEV_STATE_DEGRADED;
+	zc.zc_cookie = state;
 	zc.zc_obj = aux;
 
 	if (zfs_ioctl(hdl, ZFS_IOC_VDEV_SET_STATE, &zc) == 0)
@@ -3336,6 +3354,27 @@ zpool_vdev_degrade(zpool_handle_t *zhp, uint64_t guid, vdev_aux_t aux)
 	return (zpool_standard_error(hdl, errno, errbuf));
 }
 
+/*
+ * Mark the given vdev degraded.
+ */
+int
+zpool_vdev_degrade(zpool_handle_t *zhp, uint64_t guid, vdev_aux_t aux)
+{
+	return (zpool_vdev_set_state(zhp, guid, aux, VDEV_STATE_DEGRADED));
+}
+
+/*
+ * Mark the given vdev as in a removed state (as if the device does not exist).
+ *
+ * This is different than zpool_vdev_remove() which does a removal of a device
+ * from the pool (but the device does exist).
+ */
+int
+zpool_vdev_set_removed_state(zpool_handle_t *zhp, uint64_t guid, vdev_aux_t aux)
+{
+	return (zpool_vdev_set_state(zhp, guid, aux, VDEV_STATE_REMOVED));
+}
+
 /*
  * Returns TRUE if the given nvlist is a vdev that was originally swapped in as
  * a hot spare.

lib/libzutil/os/linux/zutil_import_os.c

@@ -170,25 +170,17 @@ zpool_open_func(void *arg)
 	if (rn->rn_labelpaths) {
 		const char *path = NULL;
 		const char *devid = NULL;
-		const char *env = NULL;
 		rdsk_node_t *slice;
 		avl_index_t where;
-		int timeout;
 		int error;
 
 		if (label_paths(rn->rn_hdl, rn->rn_config, &path, &devid))
 			return;
 
-		env = getenv("ZPOOL_IMPORT_UDEV_TIMEOUT_MS");
-		if ((env == NULL) || sscanf(env, "%d", &timeout) != 1 ||
-		    timeout < 0) {
-			timeout = DISK_LABEL_WAIT;
-		}
-
 		/*
 		 * Allow devlinks to stabilize so all paths are available.
 		 */
-		zpool_label_disk_wait(rn->rn_name, timeout);
+		zpool_disk_wait(rn->rn_name);
 
 		if (path != NULL) {
 			slice = zutil_alloc(hdl, sizeof (rdsk_node_t));
@@ -682,6 +674,20 @@ zpool_label_disk_wait(const char *path, int timeout_ms)
 #endif /* HAVE_LIBUDEV */
 }
 
+/*
+ * Simplified version of zpool_label_disk_wait() where we wait for a device
+ * to appear using the default timeouts.
+ */
+int
+zpool_disk_wait(const char *path)
+{
+	int timeout;
+	timeout = zpool_getenv_int("ZPOOL_IMPORT_UDEV_TIMEOUT_MS",
+	    DISK_LABEL_WAIT);
+
+	return (zpool_label_disk_wait(path, timeout));
+}
+
 /*
  * Encode the persistent devices strings
  * used for the vdev disk label
@@ -767,6 +773,10 @@ no_dev:
  * in the nvlist * (if applicable).  Like:
  *    vdev_enc_sysfs_path: '/sys/class/enclosure/11:0:1:0/SLOT 4'
  *
+ * If an old path was in the nvlist, and the rescan can not find a new path,
+ * then keep the old path, since the disk may have been removed.
+ *
+ * path: The vdev path (value from ZPOOL_CONFIG_PATH)
  * key: The nvlist_t name (like ZPOOL_CONFIG_VDEV_ENC_SYSFS_PATH)
  */
 void
@@ -774,6 +784,9 @@ update_vdev_config_dev_sysfs_path(nvlist_t *nv, const char *path,
     const char *key)
 {
 	char *upath, *spath;
+	const char *oldpath = NULL;
+
+	(void) nvlist_lookup_string(nv, key, &oldpath);
 
 	/* Add enclosure sysfs path (if disk is in an enclosure). */
 	upath = zfs_get_underlying_path(path);
@@ -782,7 +795,14 @@ update_vdev_config_dev_sysfs_path(nvlist_t *nv, const char *path,
 	if (spath) {
 		(void) nvlist_add_string(nv, key, spath);
 	} else {
-		(void) nvlist_remove_all(nv, key);
+		/*
+		 * We couldn't dynamically scan the disk's enclosure sysfs path.
+		 * This could be because the disk went away.  If there's an old
+		 * enclosure sysfs path in the nvlist, then keep using it.
+		 */
+		if (!oldpath) {
+			(void) nvlist_remove_all(nv, key);
+		}
 	}
 
 	free(upath);

lib/libzutil/zutil_import.c

@@ -1898,6 +1898,104 @@ zpool_find_config(libpc_handle_t *hdl, const char *target, nvlist_t **configp,
 	return (0);
 }
 
+/* Return if a vdev is a leaf vdev.  Note: draid spares are leaf vdevs. */
+static boolean_t
+vdev_is_leaf(nvlist_t *nv)
+{
+	uint_t children = 0;
+	nvlist_t **child;
+
+	(void) nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
+	    &child, &children);
+
+	return (children == 0);
+}
+
+/* Return if a vdev is a leaf vdev and a real device (disk or file) */
+static boolean_t
+vdev_is_real_leaf(nvlist_t *nv)
+{
+	const char *type = NULL;
+	if (!vdev_is_leaf(nv))
+		return (B_FALSE);
+
+	(void) nvlist_lookup_string(nv, ZPOOL_CONFIG_TYPE, &type);
+	if ((strcmp(type, VDEV_TYPE_DISK) == 0) ||
+	    (strcmp(type, VDEV_TYPE_FILE) == 0)) {
+		return (B_TRUE);
+	}
+
+	return (B_FALSE);
+}
+
+/*
+ * This function is called by our FOR_EACH_VDEV() macros.
+ *
+ * state:   State machine status (stored inside of a (nvlist_t *))
+ * nv:	     The current vdev nvlist_t we are iterating over.
+ * last_nv: The previous vdev nvlist_t we returned to the user in
+ *          the last iteration of FOR_EACH_VDEV().  We use it
+ *          to find the next vdev nvlist_t we should return.
+ * real_leaves_only: Only return leaf vdevs.
+ *
+ * Returns 1 if we found the next vdev nvlist_t for this iteration.  0 if
+ * we're still searching for it.
+ */
+static int
+__for_each_vdev_macro_helper_func(void *state, nvlist_t *nv, void *last_nv,
+    boolean_t real_leaves_only)
+{
+	enum {FIRST_NV = 0, NEXT_IS_MATCH = 1, STOP_LOOKING = 2};
+
+	/* The very first entry in the NV list is a special case */
+	if (*((nvlist_t **)state) == (nvlist_t *)FIRST_NV) {
+		if (real_leaves_only && !vdev_is_real_leaf(nv))
+			return (0);
+
+		*((nvlist_t **)last_nv) = nv;
+		*((nvlist_t **)state) = (nvlist_t *)STOP_LOOKING;
+		return (1);
+	}
+
+	/*
+	 * We came across our last_nv, meaning the next one is the one we
+	 * want
+	 */
+	if (nv == *((nvlist_t **)last_nv)) {
+		/* Next iteration of this function will return the nvlist_t */
+		*((nvlist_t **)state) = (nvlist_t *)NEXT_IS_MATCH;
+		return (0);
+	}
+
+	/*
+	 * We marked NEXT_IS_MATCH on the previous iteration, so this is the one
+	 * we want.
+	 */
+	if (*(nvlist_t **)state == (nvlist_t *)NEXT_IS_MATCH) {
+		if (real_leaves_only && !vdev_is_real_leaf(nv))
+			return (0);
+
+		*((nvlist_t **)last_nv) = nv;
+		*((nvlist_t **)state) = (nvlist_t *)STOP_LOOKING;
+		return (1);
+	}
+
+	return (0);
+}
+
+int
+for_each_vdev_macro_helper_func(void *state, nvlist_t *nv, void *last_nv)
+{
+	return (__for_each_vdev_macro_helper_func(state, nv, last_nv, B_FALSE));
+}
+
+int
+for_each_real_leaf_vdev_macro_helper_func(void *state, nvlist_t *nv,
+    void *last_nv)
+{
+	return (__for_each_vdev_macro_helper_func(state, nv, last_nv, B_TRUE));
+}
+
 /*
  * Internal function for iterating over the vdevs.
  *

lib/libzutil/zutil_pool.c

@@ -28,6 +28,7 @@
 #include <string.h>
 #include <sys/nvpair.h>
 #include <sys/fs/zfs.h>
+#include <math.h>
 
 #include <libzutil.h>
 
@@ -144,3 +145,33 @@ zpool_history_unpack(char *buf, uint64_t bytes_read, uint64_t *leftover,
 	*leftover = bytes_read;
 	return (0);
 }
+
+/*
+ * Floating point sleep().  Allows you to pass in a floating point value for
+ * seconds.
+ */
+void
+fsleep(float sec)
+{
+	struct timespec req;
+	req.tv_sec = floor(sec);
+	req.tv_nsec = (sec - (float)req.tv_sec) * NANOSEC;
+	nanosleep(&req, NULL);
+}
+
+/*
+ * Get environment variable 'env' and return it as an integer.
+ * If 'env' is not set, then return 'default_val' instead.
+ */
+int
+zpool_getenv_int(const char *env, int default_val)
+{
+	char *str;
+	int val;
+	str = getenv(env);
+	if ((str == NULL) || sscanf(str, "%d", &val) != 1 ||
+	    val < 0) {
+		val = default_val;
+	}
+	return (val);
+}