Add pool state /proc entry, "SUSPENDED" pools

1. Add a proc entry to display the pool's state:

$ cat /proc/spl/kstat/zfs/tank/state
ONLINE

This is done without using the spa config locks, so it will
never hang.

2. Fix 'zpool status' and 'zpool list -o health' output to print
"SUSPENDED" instead of "ONLINE" for suspended pools.

Reviewed-by: Olaf Faaland <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed by: Richard Elling <[email protected]>
Signed-off-by: Tony Hutter <[email protected]>
Closes #7331 
Closes #7563 

3 files changed, 42 insertions, 18 deletions

diff --git a/lib/libspl/include/sys/kstat.h b/lib/libspl/include/sys/kstat.h
index 24c71e27c..9bd0d949d 100644
--- a/lib/libspl/include/sys/kstat.h
+++ b/lib/libspl/include/sys/kstat.h
@@ -304,6 +304,8 @@ typedef struct kstat32 {
 #define	KSTAT_FLAG_PERSISTENT		0x08
 #define	KSTAT_FLAG_DORMANT		0x10
 #define	KSTAT_FLAG_INVALID		0x20
+#define	KSTAT_FLAG_LONGSTRINGS		0x40
+#define	KSTAT_FLAG_NO_HEADERS		0x80
 
 /*
  * Dynamic update support
diff --git a/lib/libzfs/libzfs_pool.c b/lib/libzfs/libzfs_pool.c
index 3b16c012f..16b30d177 100644
--- a/lib/libzfs/libzfs_pool.c
+++ b/lib/libzfs/libzfs_pool.c
@@ -243,6 +243,38 @@ zpool_pool_state_to_name(pool_state_t state)
 }
 
 /*
+ * Given a pool handle, return the pool health string ("ONLINE", "DEGRADED",
+ * "SUSPENDED", etc).
+ */
+const char *
+zpool_get_state_str(zpool_handle_t *zhp)
+{
+	zpool_errata_t errata;
+	zpool_status_t status;
+	nvlist_t *nvroot;
+	vdev_stat_t *vs;
+	uint_t vsc;
+	const char *str;
+
+	status = zpool_get_status(zhp, NULL, &errata);
+
+	if (zpool_get_state(zhp) == POOL_STATE_UNAVAIL) {
+		str = gettext("FAULTED");
+	} else if (status == ZPOOL_STATUS_IO_FAILURE_WAIT ||
+	    status == ZPOOL_STATUS_IO_FAILURE_MMP) {
+		str = gettext("SUSPENDED");
+	} else {
+		verify(nvlist_lookup_nvlist(zpool_get_config(zhp, NULL),
+		    ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
+		verify(nvlist_lookup_uint64_array(nvroot,
+		    ZPOOL_CONFIG_VDEV_STATS, (uint64_t **)&vs, &vsc)
+		    == 0);
+		str = zpool_state_to_name(vs->vs_state, vs->vs_aux);
+	}
+	return (str);
+}
+
+/*
  * Get a zpool property value for 'prop' and return the value in
  * a pre-allocated buffer.
  */
@@ -253,9 +285,6 @@ zpool_get_prop(zpool_handle_t *zhp, zpool_prop_t prop, char *buf,
 	uint64_t intval;
 	const char *strval;
 	zprop_source_t src = ZPROP_SRC_NONE;
-	nvlist_t *nvroot;
-	vdev_stat_t *vs;
-	uint_t vsc;
 
 	if (zpool_get_state(zhp) == POOL_STATE_UNAVAIL) {
 		switch (prop) {
@@ -264,7 +293,7 @@ zpool_get_prop(zpool_handle_t *zhp, zpool_prop_t prop, char *buf,
 			break;
 
 		case ZPOOL_PROP_HEALTH:
-			(void) strlcpy(buf, "FAULTED", len);
+			(void) strlcpy(buf, zpool_get_state_str(zhp), len);
 			break;
 
 		case ZPOOL_PROP_GUID:
@@ -365,14 +394,7 @@ zpool_get_prop(zpool_handle_t *zhp, zpool_prop_t prop, char *buf,
 			break;
 
 		case ZPOOL_PROP_HEALTH:
-			verify(nvlist_lookup_nvlist(zpool_get_config(zhp, NULL),
-			    ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
-			verify(nvlist_lookup_uint64_array(nvroot,
-			    ZPOOL_CONFIG_VDEV_STATS, (uint64_t **)&vs, &vsc)
-			    == 0);
-
-			(void) strlcpy(buf, zpool_state_to_name(intval,
-			    vs->vs_aux), len);
+			(void) strlcpy(buf, zpool_get_state_str(zhp), len);
 			break;
 		case ZPOOL_PROP_VERSION:
 			if (intval >= SPA_VERSION_FEATURES) {
diff --git a/lib/libzfs/libzfs_status.c b/lib/libzfs/libzfs_status.c
index 57d2deabf..4089f0cc6 100644
--- a/lib/libzfs/libzfs_status.c
+++ b/lib/libzfs/libzfs_status.c
@@ -404,12 +404,12 @@ zpool_status_t
 zpool_get_status(zpool_handle_t *zhp, char **msgid, zpool_errata_t *errata)
 {
 	zpool_status_t ret = check_status(zhp->zpool_config, B_FALSE, errata);
-
-	if (ret >= NMSGID)
-		*msgid = NULL;
-	else
-		*msgid = zfs_msgid_table[ret];
-
+	if (msgid != NULL) {
+		if (ret >= NMSGID)
+			*msgid = NULL;
+		else
+			*msgid = zfs_msgid_table[ret];
+	}
 	return (ret);
 }