Multipath autoreplace, control enclosure LEDs, event rate limiting

1. Enable multipath autoreplace support for FMA.

This extends FMA autoreplace to work with multipath disks.  This
requires libdevmapper to be installed at build time.

2. Turn on/off fault LEDs when VDEVs become degraded/faulted/online

Set ZED_USE_ENCLOSURE_LEDS=1 in zed.rc to have ZED turn on/off the enclosure
LED for a drive when a drive becomes FAULTED/DEGRADED.  Your enclosure must
be supported by the Linux SES driver for this to work.  The enclosure LED
scripts work for multipath devices as well.  The scripts will clear the LED
when the fault is cleared.

3. Rate limit ZIO delay and checksum events so as not to flood ZED

ZIO delay and checksum events are rate limited to 5/sec in the zfs module.

Reviewed-by: Richard Laager <[email protected]>
Reviewed by: Don Brady <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tony Hutter <[email protected]>
Closes #2449 
Closes #3017 
Closes #5159 

1 files changed, 37 insertions, 0 deletions

diff --git a/include/sys/zfs_ratelimit.h b/include/sys/zfs_ratelimit.h
new file mode 100644
index 000000000..b9f9f73dc
--- /dev/null
+++ b/include/sys/zfs_ratelimit.h
@@ -0,0 +1,37 @@
+/*
+ * CDDL HEADER START
+ *
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2016, Lawrence Livermore National Security, LLC.
+ */
+
+#ifndef _SYS_ZFS_RATELIMIT_H
+#define	_SYS_ZFS_RATELIMIT_H
+
+#include <sys/zfs_context.h>
+
+typedef struct {
+	hrtime_t start;
+	unsigned int count;
+	unsigned int burst;		/* Number to allow per interval */
+	unsigned int interval;		/* Interval length in seconds */
+	kmutex_t lock;
+} zfs_ratelimit_t;
+
+int zfs_ratelimit(zfs_ratelimit_t *rl);
+void zfs_ratelimit_init(zfs_ratelimit_t *rl, unsigned int burst,
+    unsigned int interval);
+
+#endif	/* _SYS_ZFS_RATELIMIT_H */