zed: detect and offline physically removed devices

This commit adds a new test case to the ZFS Test Suite to verify ZED
can detect when a device is physically removed from a running system:
the device will be offlined if a spare is not available in the pool.

We implement this by using the existing libudev functionality and
without relying solely on the FM kernel module capabilities which have
been observed to be unreliable with some kernels.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Don Brady <[email protected]>
Signed-off-by: loli10K <[email protected]>
Closes #1537
Closes #7926

1 files changed, 44 insertions, 11 deletions

diff --git a/cmd/zed/agents/zfs_retire.c b/cmd/zed/agents/zfs_retire.c
index 5a090e32f..f3dbb24b8 100644
--- a/cmd/zed/agents/zfs_retire.c
+++ b/cmd/zed/agents/zfs_retire.c
@@ -22,6 +22,7 @@
  * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
  *
  * Copyright (c) 2016, Intel Corporation.
+ * Copyright (c) 2018, loli10K <[email protected]>
  */
 
 /*
@@ -126,6 +127,15 @@ find_vdev(libzfs_handle_t *zhdl, nvlist_t *nv, uint64_t search_guid)
 			return (ret);
 	}
 
+	if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_SPARES,
+	    &child, &children) != 0)
+		return (NULL);
+
+	for (c = 0; c < children; c++) {
+		if ((ret = find_vdev(zhdl, child[c], search_guid)) != NULL)
+			return (ret);
+	}
+
 	return (NULL);
 }
 
@@ -167,9 +177,10 @@ find_by_guid(libzfs_handle_t *zhdl, uint64_t pool_guid, uint64_t vdev_guid,
 
 /*
  * Given a vdev, attempt to replace it with every known spare until one
- * succeeds.
+ * succeeds or we run out of devices to try.
+ * Return whether we were successful or not in replacing the device.
  */
-static void
+static boolean_t
 replace_with_spare(fmd_hdl_t *hdl, zpool_handle_t *zhp, nvlist_t *vdev)
 {
 	nvlist_t *config, *nvroot, *replacement;
@@ -182,14 +193,14 @@ replace_with_spare(fmd_hdl_t *hdl, zpool_handle_t *zhp, nvlist_t *vdev)
 	config = zpool_get_config(zhp, NULL);
 	if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
 	    &nvroot) != 0)
-		return;
+		return (B_FALSE);
 
 	/*
 	 * Find out if there are any hot spares available in the pool.
 	 */
 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
 	    &spares, &nspares) != 0)
-		return;
+		return (B_FALSE);
 
 	/*
 	 * lookup "ashift" pool property, we may need it for the replacement
@@ -226,12 +237,17 @@ replace_with_spare(fmd_hdl_t *hdl, zpool_handle_t *zhp, nvlist_t *vdev)
 		    dev_name, basename(spare_name));
 
 		if (zpool_vdev_attach(zhp, dev_name, spare_name,
-		    replacement, B_TRUE) == 0)
-			break;
+		    replacement, B_TRUE) == 0) {
+			free(dev_name);
+			nvlist_free(replacement);
+			return (B_TRUE);
+		}
 	}
 
 	free(dev_name);
 	nvlist_free(replacement);
+
+	return (B_FALSE);
 }
 
 /*
@@ -304,10 +320,14 @@ zfs_retire_recv(fmd_hdl_t *hdl, fmd_event_t *ep, nvlist_t *nvl,
 	fmd_hdl_debug(hdl, "zfs_retire_recv: '%s'", class);
 
 	/*
-	 * If this is a resource notifying us of device removal, then simply
-	 * check for an available spare and continue.
+	 * If this is a resource notifying us of device removal then simply
+	 * check for an available spare and continue unless the device is a
+	 * l2arc vdev, in which case we just offline it.
 	 */
 	if (strcmp(class, "resource.fs.zfs.removed") == 0) {
+		char *devtype;
+		char *devname;
+
 		if (nvlist_lookup_uint64(nvl, FM_EREPORT_PAYLOAD_ZFS_POOL_GUID,
 		    &pool_guid) != 0 ||
 		    nvlist_lookup_uint64(nvl, FM_EREPORT_PAYLOAD_ZFS_VDEV_GUID,
@@ -318,8 +338,21 @@ zfs_retire_recv(fmd_hdl_t *hdl, fmd_event_t *ep, nvlist_t *nvl,
 		    &vdev)) == NULL)
 			return;
 
-		if (fmd_prop_get_int32(hdl, "spare_on_remove"))
-			replace_with_spare(hdl, zhp, vdev);
+		devname = zpool_vdev_name(NULL, zhp, vdev, B_FALSE);
+
+		/* Can't replace l2arc with a spare: offline the device */
+		if (nvlist_lookup_string(nvl, FM_EREPORT_PAYLOAD_ZFS_VDEV_TYPE,
+		    &devtype) == 0 && strcmp(devtype, VDEV_TYPE_L2CACHE) == 0) {
+			fmd_hdl_debug(hdl, "zpool_vdev_offline '%s'", devname);
+			zpool_vdev_offline(zhp, devname, B_TRUE);
+		} else if (!fmd_prop_get_int32(hdl, "spare_on_remove") ||
+		    replace_with_spare(hdl, zhp, vdev) == B_FALSE) {
+			/* Could not handle with spare: offline the device */
+			fmd_hdl_debug(hdl, "zpool_vdev_offline '%s'", devname);
+			zpool_vdev_offline(zhp, devname, B_TRUE);
+		}
+
+		free(devname);
 		zpool_close(zhp);
 		return;
 	}
@@ -463,7 +496,7 @@ zfs_retire_recv(fmd_hdl_t *hdl, fmd_event_t *ep, nvlist_t *nvl,
 		/*
 		 * Attempt to substitute a hot spare.
 		 */
-		replace_with_spare(hdl, zhp, vdev);
+		(void) replace_with_spare(hdl, zhp, vdev);
 		zpool_close(zhp);
 	}