Add linux events

This topic branch leverages the Solaris style FMA call points
in ZFS to create a user space visible event notification system
under Linux.  This new system is called zevent and it unifies
all previous Solaris style ereports and sysevent notifications.

Under this Linux specific scheme when a sysevent or ereport event
occurs an nvlist describing the event is created which looks almost
exactly like a Solaris ereport.  These events are queued up in the
kernel when they occur and conditionally logged to the console.
It is then up to a user space application to consume the events
and do whatever it likes with them.

To make this possible the existing /dev/zfs ABI has been extended
with two new ioctls which behave as follows.

* ZFS_IOC_EVENTS_NEXT
Get the next pending event.  The kernel will keep track of the last
event consumed by the file descriptor and provide the next one if
available.  If no new events are available the ioctl() will block
waiting for the next event.  This ioctl may also be called in a
non-blocking mode by setting zc.zc_guid = ZEVENT_NONBLOCK.  In the
non-blocking case if no events are available ENOENT will be returned.
It is possible that ESHUTDOWN will be returned if the ioctl() is
called while module unloading is in progress.  And finally ENOMEM
may occur if the provided nvlist buffer is not large enough to
contain the entire event.

* ZFS_IOC_EVENTS_CLEAR
Clear are events queued by the kernel.  The kernel will keep a fairly
large number of recent events queued, use this ioctl to clear the
in kernel list.  This will effect all user space processes consuming
events.

The zpool command has been extended to use this events ABI with the
'events' subcommand.  You may run 'zpool events -v' to output a
verbose log of all recent events.  This is very similar to the
Solaris 'fmdump -ev' command with the key difference being it also
includes what would be considered sysevents under Solaris.  You
may also run in follow mode with the '-f' option.  To clear the
in kernel event queue use the '-c' option.

$ sudo cmd/zpool/zpool events -fv
TIME                        CLASS
May 13 2010 16:31:15.777711000 ereport.fs.zfs.config.sync
        class = "ereport.fs.zfs.config.sync"
        ena = 0x40982b7897700001
        detector = (embedded nvlist)
                version = 0x0
                scheme = "zfs"
                pool = 0xed976600de75dfa6
        (end detector)

        time = 0x4bec8bc3 0x2e5aed98
        pool = "zpios"
        pool_guid = 0xed976600de75dfa6
        pool_context = 0x0

While the 'zpool events' command is handy for interactive debugging
it is not expected to be the primary consumer of zevents.  This ABI
was primarily added to facilitate the addition of a user space
monitoring daemon.  This daemon would consume all events posted by
the kernel and based on the type of event perform an action.  For
most events simply forwarding them on to syslog is likely enough.
But this interface also cleanly allows for more sophisticated
actions to be taken such as generating an email for a failed drive.

Signed-off-by: Brian Behlendorf <[email protected]>

1 files changed, 496 insertions, 348 deletions

diff --git a/module/zfs/fm.c b/module/zfs/fm.c
index 4efcff4f4..67d0c1a6e 100644
--- a/module/zfs/fm.c
+++ b/module/zfs/fm.c
@@ -53,51 +53,46 @@
 
 #include <sys/types.h>
 #include <sys/time.h>
-#include <sys/sysevent.h>
-#include <sys/sysevent_impl.h>
+#include <sys/list.h>
 #include <sys/nvpair.h>
 #include <sys/cmn_err.h>
-#include <sys/cpuvar.h>
 #include <sys/sysmacros.h>
-#include <sys/systm.h>
-#include <sys/ddifm.h>
-#include <sys/ddifm_impl.h>
-#include <sys/spl.h>
-#include <sys/dumphdr.h>
 #include <sys/compress.h>
-#include <sys/cpuvar.h>
-#include <sys/console.h>
-#include <sys/panic.h>
-#include <sys/kobj.h>
 #include <sys/sunddi.h>
 #include <sys/systeminfo.h>
-#include <sys/sysevent/eventdefs.h>
 #include <sys/fm/util.h>
 #include <sys/fm/protocol.h>
+#include <sys/kstat.h>
+#include <sys/zfs_context.h>
+#ifdef _KERNEL
+#include <sys/atomic.h>
+#include <sys/condvar.h>
+#include <sys/cpuvar.h>
+#include <sys/systm.h>
+#include <sys/dumphdr.h>
+#include <sys/cpuvar.h>
+#include <sys/console.h>
+#include <sys/kobj.h>
+#include <sys/time.h>
+#include <sys/zfs_ioctl.h>
 
-/*
- * URL and SUNW-MSG-ID value to display for fm_panic(), defined below.  These
- * values must be kept in sync with the FMA source code in usr/src/cmd/fm.
- */
-static const char *fm_url = "http://www.sun.com/msg";
-static const char *fm_msgid = "SUNOS-8000-0G";
-static char *volatile fm_panicstr = NULL;
+int zevent_len_max = 0;
+int zevent_cols = 80;
+int zevent_console = 0;
 
-errorq_t *ereport_errorq;
-void *ereport_dumpbuf;
-size_t ereport_dumplen;
+static int zevent_len_cur = 0;
+static int zevent_waiters = 0;
+static int zevent_flags = 0;
 
-static uint_t ereport_chanlen = ERPT_EVCH_MAX;
-static evchan_t *ereport_chan = NULL;
-static ulong_t ereport_qlen = 0;
-static size_t ereport_size = 0;
-static int ereport_cols = 80;
+static kmutex_t zevent_lock;
+static list_t zevent_list;
+static kcondvar_t zevent_cv;
+#endif /* _KERNEL */
 
 extern void fastreboot_disable_highpil(void);
 
 /*
- * Common fault management kstats to record ereport generation
- * failures
+ * Common fault management kstats to record event generation failures
  */
 
 struct erpt_kstat {
@@ -114,57 +109,9 @@ static struct erpt_kstat erpt_kstat_data = {
 	{ "payload-set-failed", KSTAT_DATA_UINT64 }
 };
 
-/*ARGSUSED*/
-static void
-fm_drain(void *private, void *data, errorq_elem_t *eep)
-{
-	nvlist_t *nvl = errorq_elem_nvl(ereport_errorq, eep);
-
-	if (!panicstr)
-		(void) fm_ereport_post(nvl, EVCH_TRYHARD);
-	else
-		fm_nvprint(nvl);
-}
-
-void
-fm_init(void)
-{
-	kstat_t *ksp;
+kstat_t *fm_ksp;
 
-	(void) sysevent_evc_bind(FM_ERROR_CHAN,
-	    &ereport_chan, EVCH_CREAT | EVCH_HOLD_PEND);
-
-	(void) sysevent_evc_control(ereport_chan,
-	    EVCH_SET_CHAN_LEN, &ereport_chanlen);
-
-	if (ereport_qlen == 0)
-		ereport_qlen = ERPT_MAX_ERRS * MAX(max_ncpus, 4);
-
-	if (ereport_size == 0)
-		ereport_size = ERPT_DATA_SZ;
-
-	ereport_errorq = errorq_nvcreate("fm_ereport_queue",
-	    (errorq_func_t)fm_drain, NULL, ereport_qlen, ereport_size,
-	    FM_ERR_PIL, ERRORQ_VITAL);
-	if (ereport_errorq == NULL)
-		panic("failed to create required ereport error queue");
-
-	ereport_dumpbuf = kmem_alloc(ereport_size, KM_SLEEP);
-	ereport_dumplen = ereport_size;
-
-	/* Initialize ereport allocation and generation kstats */
-	ksp = kstat_create("unix", 0, "fm", "misc", KSTAT_TYPE_NAMED,
-	    sizeof (struct erpt_kstat) / sizeof (kstat_named_t),
-	    KSTAT_FLAG_VIRTUAL);
-
-	if (ksp != NULL) {
-		ksp->ks_data = &erpt_kstat_data;
-		kstat_install(ksp);
-	} else {
-		cmn_err(CE_NOTE, "failed to create fm/misc kstat\n");
-
-	}
-}
+#ifdef _KERNEL
 
 /*
  * Formatting utility function for fm_nvprintr.  We attempt to wrap chunks of
@@ -183,7 +130,7 @@ fm_printf(int depth, int c, int cols, const char *format, ...)
 	va_end(ap);
 
 	if (c + width >= cols) {
-		console_printf("\n\r");
+		console_printf("\n");
 		c = 0;
 		if (format[0] != ' ' && depth > 0) {
 			console_printf(" ");
@@ -245,54 +192,54 @@ fm_nvprintr(nvlist_t *nvl, int d, int c, int cols)
 
 		case DATA_TYPE_BYTE:
 			(void) nvpair_value_byte(nvp, &i8);
-			c = fm_printf(d + 1, c, cols, "%x", i8);
+			c = fm_printf(d + 1, c, cols, "0x%x", i8);
 			break;
 
 		case DATA_TYPE_INT8:
 			(void) nvpair_value_int8(nvp, (void *)&i8);
-			c = fm_printf(d + 1, c, cols, "%x", i8);
+			c = fm_printf(d + 1, c, cols, "0x%x", i8);
 			break;
 
 		case DATA_TYPE_UINT8:
 			(void) nvpair_value_uint8(nvp, &i8);
-			c = fm_printf(d + 1, c, cols, "%x", i8);
+			c = fm_printf(d + 1, c, cols, "0x%x", i8);
 			break;
 
 		case DATA_TYPE_INT16:
 			(void) nvpair_value_int16(nvp, (void *)&i16);
-			c = fm_printf(d + 1, c, cols, "%x", i16);
+			c = fm_printf(d + 1, c, cols, "0x%x", i16);
 			break;
 
 		case DATA_TYPE_UINT16:
 			(void) nvpair_value_uint16(nvp, &i16);
-			c = fm_printf(d + 1, c, cols, "%x", i16);
+			c = fm_printf(d + 1, c, cols, "0x%x", i16);
 			break;
 
 		case DATA_TYPE_INT32:
 			(void) nvpair_value_int32(nvp, (void *)&i32);
-			c = fm_printf(d + 1, c, cols, "%x", i32);
+			c = fm_printf(d + 1, c, cols, "0x%x", i32);
 			break;
 
 		case DATA_TYPE_UINT32:
 			(void) nvpair_value_uint32(nvp, &i32);
-			c = fm_printf(d + 1, c, cols, "%x", i32);
+			c = fm_printf(d + 1, c, cols, "0x%x", i32);
 			break;
 
 		case DATA_TYPE_INT64:
 			(void) nvpair_value_int64(nvp, (void *)&i64);
-			c = fm_printf(d + 1, c, cols, "%llx",
+			c = fm_printf(d + 1, c, cols, "0x%llx",
 			    (u_longlong_t)i64);
 			break;
 
 		case DATA_TYPE_UINT64:
 			(void) nvpair_value_uint64(nvp, &i64);
-			c = fm_printf(d + 1, c, cols, "%llx",
+			c = fm_printf(d + 1, c, cols, "0x%llx",
 			    (u_longlong_t)i64);
 			break;
 
 		case DATA_TYPE_HRTIME:
 			(void) nvpair_value_hrtime(nvp, (void *)&i64);
-			c = fm_printf(d + 1, c, cols, "%llx",
+			c = fm_printf(d + 1, c, cols, "0x%llx",
 			    (u_longlong_t)i64);
 			break;
 
@@ -322,19 +269,124 @@ fm_nvprintr(nvlist_t *nvl, int d, int c, int cols)
 			}
 			break;
 
+		case DATA_TYPE_INT8_ARRAY: {
+			int8_t *val;
+			uint_t i, nelem;
+
+			c = fm_printf(d + 1, c, cols, "[ ");
+			(void) nvpair_value_int8_array(nvp, &val, &nelem);
+			for (i = 0; i < nelem; i++)
+			        c = fm_printf(d + 1, c, cols, "0x%llx ",
+					      (u_longlong_t)val[i]);
+
+			c = fm_printf(d + 1, c, cols, "]");
+			break;
+			}
+
+		case DATA_TYPE_UINT8_ARRAY: {
+			uint8_t *val;
+			uint_t i, nelem;
+
+			c = fm_printf(d + 1, c, cols, "[ ");
+			(void) nvpair_value_uint8_array(nvp, &val, &nelem);
+			for (i = 0; i < nelem; i++)
+			        c = fm_printf(d + 1, c, cols, "0x%llx ",
+					      (u_longlong_t)val[i]);
+
+			c = fm_printf(d + 1, c, cols, "]");
+			break;
+			}
+
+		case DATA_TYPE_INT16_ARRAY: {
+			int16_t *val;
+			uint_t i, nelem;
+
+			c = fm_printf(d + 1, c, cols, "[ ");
+			(void) nvpair_value_int16_array(nvp, &val, &nelem);
+			for (i = 0; i < nelem; i++)
+			        c = fm_printf(d + 1, c, cols, "0x%llx ",
+					      (u_longlong_t)val[i]);
+
+			c = fm_printf(d + 1, c, cols, "]");
+			break;
+			}
+
+		case DATA_TYPE_UINT16_ARRAY: {
+			uint16_t *val;
+			uint_t i, nelem;
+
+			c = fm_printf(d + 1, c, cols, "[ ");
+			(void) nvpair_value_uint16_array(nvp, &val, &nelem);
+			for (i = 0; i < nelem; i++)
+			        c = fm_printf(d + 1, c, cols, "0x%llx ",
+					      (u_longlong_t)val[i]);
+
+			c = fm_printf(d + 1, c, cols, "]");
+			break;
+			}
+
+		case DATA_TYPE_INT32_ARRAY: {
+			int32_t *val;
+			uint_t i, nelem;
+
+			c = fm_printf(d + 1, c, cols, "[ ");
+			(void) nvpair_value_int32_array(nvp, &val, &nelem);
+			for (i = 0; i < nelem; i++)
+			        c = fm_printf(d + 1, c, cols, "0x%llx ",
+					      (u_longlong_t)val[i]);
+
+			c = fm_printf(d + 1, c, cols, "]");
+			break;
+			}
+
+		case DATA_TYPE_UINT32_ARRAY: {
+			uint32_t *val;
+			uint_t i, nelem;
+
+			c = fm_printf(d + 1, c, cols, "[ ");
+			(void) nvpair_value_uint32_array(nvp, &val, &nelem);
+			for (i = 0; i < nelem; i++)
+			        c = fm_printf(d + 1, c, cols, "0x%llx ",
+					      (u_longlong_t)val[i]);
+
+			c = fm_printf(d + 1, c, cols, "]");
+			break;
+			}
+
+		case DATA_TYPE_INT64_ARRAY: {
+			int64_t *val;
+			uint_t i, nelem;
+
+			c = fm_printf(d + 1, c, cols, "[ ");
+			(void) nvpair_value_int64_array(nvp, &val, &nelem);
+			for (i = 0; i < nelem; i++)
+			        c = fm_printf(d + 1, c, cols, "0x%llx ",
+					      (u_longlong_t)val[i]);
+
+			c = fm_printf(d + 1, c, cols, "]");
+			break;
+			}
+
+		case DATA_TYPE_UINT64_ARRAY: {
+			uint64_t *val;
+			uint_t i, nelem;
+
+			c = fm_printf(d + 1, c, cols, "[ ");
+			(void) nvpair_value_uint64_array(nvp, &val, &nelem);
+			for (i = 0; i < nelem; i++)
+			        c = fm_printf(d + 1, c, cols, "0x%llx ",
+					      (u_longlong_t)val[i]);
+
+			c = fm_printf(d + 1, c, cols, "]");
+			break;
+			}
+
+		case DATA_TYPE_STRING_ARRAY:
 		case DATA_TYPE_BOOLEAN_ARRAY:
 		case DATA_TYPE_BYTE_ARRAY:
-		case DATA_TYPE_INT8_ARRAY:
-		case DATA_TYPE_UINT8_ARRAY:
-		case DATA_TYPE_INT16_ARRAY:
-		case DATA_TYPE_UINT16_ARRAY:
-		case DATA_TYPE_INT32_ARRAY:
-		case DATA_TYPE_UINT32_ARRAY:
-		case DATA_TYPE_INT64_ARRAY:
-		case DATA_TYPE_UINT64_ARRAY:
-		case DATA_TYPE_STRING_ARRAY:
 			c = fm_printf(d + 1, c, cols, "[...]");
 			break;
+
 		case DATA_TYPE_UNKNOWN:
 			c = fm_printf(d + 1, c, cols, "<unknown>");
 			break;
@@ -350,191 +402,255 @@ fm_nvprint(nvlist_t *nvl)
 	char *class;
 	int c = 0;
 
-	console_printf("\r");
+	console_printf("\n");
 
 	if (nvlist_lookup_string(nvl, FM_CLASS, &class) == 0)
-		c = fm_printf(0, c, ereport_cols, "%s", class);
+		c = fm_printf(0, c, zevent_cols, "%s", class);
 
-	if (fm_nvprintr(nvl, 0, c, ereport_cols) != 0)
+	if (fm_nvprintr(nvl, 0, c, zevent_cols) != 0)
 		console_printf("\n");
 
 	console_printf("\n");
 }
 
-/*
- * Wrapper for panic() that first produces an FMA-style message for admins.
- * Normally such messages are generated by fmd(1M)'s syslog-msgs agent: this
- * is the one exception to that rule and the only error that gets messaged.
- * This function is intended for use by subsystems that have detected a fatal
- * error and enqueued appropriate ereports and wish to then force a panic.
- */
-/*PRINTFLIKE1*/
+static zevent_t *
+zfs_zevent_alloc(void)
+{
+	zevent_t *ev;
+
+	ev = kmem_zalloc(sizeof(zevent_t), KM_SLEEP);
+	if (ev == NULL)
+		return NULL;
+
+	list_create(&ev->ev_ze_list, sizeof(zfs_zevent_t),
+		    offsetof(zfs_zevent_t, ze_node));
+	list_link_init(&ev->ev_node);
+
+	return ev;
+}
+
+static void
+zfs_zevent_free(zevent_t *ev)
+{
+	/* Run provided cleanup callback */
+	ev->ev_cb(ev->ev_nvl, ev->ev_detector);
+
+	list_destroy(&ev->ev_ze_list);
+	kmem_free(ev, sizeof(zevent_t));
+}
+
+static void
+zfs_zevent_drain(zevent_t *ev)
+{
+	zfs_zevent_t *ze;
+
+	ASSERT(MUTEX_HELD(&zevent_lock));
+	list_remove(&zevent_list, ev);
+
+	/* Remove references to this event in all private file data */
+	while ((ze = list_head(&ev->ev_ze_list)) != NULL) {
+		list_remove(&ev->ev_ze_list, ze);
+		ze->ze_zevent = NULL;
+		ze->ze_dropped++;
+	}
+
+	zfs_zevent_free(ev);
+}
+
 void
-fm_panic(const char *format, ...)
+zfs_zevent_drain_all(int *count)
 {
-	va_list ap;
+	zevent_t *ev;
 
-	(void) casptr((void *)&fm_panicstr, NULL, (void *)format);
-#if defined(__i386) || defined(__amd64)
-	fastreboot_disable_highpil();
-#endif /* __i386 || __amd64 */
-	va_start(ap, format);
-	vpanic(format, ap);
-	va_end(ap);
+	mutex_enter(&zevent_lock);
+	while ((ev = list_head(&zevent_list)) != NULL)
+		zfs_zevent_drain(ev);
+
+	*count = zevent_len_cur;
+	zevent_len_cur = 0;
+	mutex_exit(&zevent_lock);
 }
 
 /*
- * Simply tell the caller if fm_panicstr is set, ie. an fma event has
- * caused the panic. If so, something other than the default panic
- * diagnosis method will diagnose the cause of the panic.
+ * New zevents are inserted at the head.  If the maximum queue
+ * length is exceeded a zevent will be drained from the tail.
+ * As part of this any user space processes which currently have
+ * a reference to this zevent_t in their private data will have
+ * this reference set to NULL.
  */
-int
-is_fm_panic()
+static void
+zfs_zevent_insert(zevent_t *ev)
 {
-	if (fm_panicstr)
-		return (1);
+	mutex_enter(&zevent_lock);
+	list_insert_head(&zevent_list, ev);
+	if (zevent_len_cur >= zevent_len_max)
+		zfs_zevent_drain(list_tail(&zevent_list));
 	else
-		return (0);
+		zevent_len_cur++;
+
+	mutex_exit(&zevent_lock);
 }
 
 /*
- * Print any appropriate FMA banner message before the panic message.  This
- * function is called by panicsys() and prints the message for fm_panic().
- * We print the message here so that it comes after the system is quiesced.
- * A one-line summary is recorded in the log only (cmn_err(9F) with "!" prefix).
- * The rest of the message is for the console only and not needed in the log,
- * so it is printed using console_printf().  We break it up into multiple
- * chunks so as to avoid overflowing any small legacy prom_printf() buffers.
+ * Post a zevent
  */
 void
-fm_banner(void)
+zfs_zevent_post(nvlist_t *nvl, nvlist_t *detector, zevent_cb_t *cb)
 {
-	timespec_t tod;
-	hrtime_t now;
+	int64_t tv_array[2];
+	timestruc_t tv;
+	size_t nvl_size = 0;
+	zevent_t *ev;
 
-	if (!fm_panicstr)
-		return; /* panic was not initiated by fm_panic(); do nothing */
+	gethrestime(&tv);
+	tv_array[0] = tv.tv_sec;
+	tv_array[1] = tv.tv_nsec;
+	if (nvlist_add_int64_array(nvl, FM_EREPORT_TIME, tv_array, 2)) {
+		atomic_add_64(&erpt_kstat_data.erpt_set_failed.value.ui64, 1);
+		return;
+	}
 
-	if (panicstr) {
-		tod = panic_hrestime;
-		now = panic_hrtime;
-	} else {
-		gethrestime(&tod);
-		now = gethrtime_waitfree();
+	(void) nvlist_size(nvl, &nvl_size, NV_ENCODE_NATIVE);
+	if (nvl_size > ERPT_DATA_SZ || nvl_size == 0) {
+		atomic_add_64(&erpt_kstat_data.erpt_dropped.value.ui64, 1);
+		return;
 	}
 
-	cmn_err(CE_NOTE, "!SUNW-MSG-ID: %s, "
-	    "TYPE: Error, VER: 1, SEVERITY: Major\n", fm_msgid);
+	if (zevent_console)
+		fm_nvprint(nvl);
 
-	console_printf(
-"\n\rSUNW-MSG-ID: %s, TYPE: Error, VER: 1, SEVERITY: Major\n"
-"EVENT-TIME: 0x%lx.0x%lx (0x%llx)\n",
-	    fm_msgid, tod.tv_sec, tod.tv_nsec, (u_longlong_t)now);
+	ev = zfs_zevent_alloc();
+	if (ev == NULL) {
+		atomic_add_64(&erpt_kstat_data.erpt_dropped.value.ui64, 1);
+		return;
+	}
 
-	console_printf(
-"PLATFORM: %s, CSN: -, HOSTNAME: %s\n"
-"SOURCE: %s, REV: %s %s\n",
-	    platform, utsname.nodename, utsname.sysname,
-	    utsname.release, utsname.version);
+        ev->ev_nvl = nvl;
+	ev->ev_detector = detector;
+	ev->ev_cb = cb;
+	zfs_zevent_insert(ev);
+	cv_broadcast(&zevent_cv);
+}
 
-	console_printf(
-"DESC: Errors have been detected that require a reboot to ensure system\n"
-"integrity.  See %s/%s for more information.\n",
-	    fm_url, fm_msgid);
+static int
+zfs_zevent_minor_to_state(minor_t minor, zfs_zevent_t **ze)
+{
+	*ze = zfsdev_get_state(minor, ZST_ZEVENT);
+	if (*ze == NULL)
+		return (EBADF);
 
-	console_printf(
-"AUTO-RESPONSE: Solaris will attempt to save and diagnose the error telemetry\n"
-"IMPACT: The system will sync files, save a crash dump if needed, and reboot\n"
-"REC-ACTION: Save the error summary below in case telemetry cannot be saved\n");
+	return (0);
+}
 
-	console_printf("\n");
+int
+zfs_zevent_fd_hold(int fd, minor_t *minorp, zfs_zevent_t **ze)
+{
+	file_t *fp;
+	int error;
+
+        fp = getf(fd);
+        if (fp == NULL)
+                return (EBADF);
+
+        *minorp = zfsdev_getminor(fp->f_file);
+        error = zfs_zevent_minor_to_state(*minorp, ze);
+
+	if (error)
+		zfs_zevent_fd_rele(fd);
+
+	return (error);
+}
+
+void
+zfs_zevent_fd_rele(int fd)
+{
+	releasef(fd);
 }
 
 /*
- * Utility function to write all of the pending ereports to the dump device.
- * This function is called at either normal reboot or panic time, and simply
- * iterates over the in-transit messages in the ereport sysevent channel.
+ * Get the next zevent in the stream and place a copy in 'event'.
  */
-void
-fm_ereport_dump(void)
+int
+zfs_zevent_next(zfs_zevent_t *ze, nvlist_t **event, uint64_t *dropped)
 {
-	evchanq_t *chq;
-	sysevent_t *sep;
-	erpt_dump_t ed;
-
-	timespec_t tod;
-	hrtime_t now;
-	char *buf;
-	size_t len;
-
-	if (panicstr) {
-		tod = panic_hrestime;
-		now = panic_hrtime;
+	zevent_t *ev;
+	int error;
+
+	mutex_enter(&zevent_lock);
+	if (ze->ze_zevent == NULL) {
+		/* New stream start at the beginning/tail */
+		ev = list_tail(&zevent_list);
+		if (ev == NULL) {
+			error = ENOENT;
+			goto out;
+		}
 	} else {
-		if (ereport_errorq != NULL)
-			errorq_drain(ereport_errorq);
-		gethrestime(&tod);
-		now = gethrtime_waitfree();
+		/* Existing stream continue with the next element and remove
+		 * ourselves from the wait queue for the previous element */
+		ev = list_prev(&zevent_list, ze->ze_zevent);
+		if (ev == NULL) {
+			error = ENOENT;
+			goto out;
+		}
+
+		list_remove(&ze->ze_zevent->ev_ze_list, ze);
 	}
 
-	/*
-	 * In the panic case, sysevent_evc_walk_init() will return NULL.
-	 */
-	if ((chq = sysevent_evc_walk_init(ereport_chan, NULL)) == NULL &&
-	    !panicstr)
-		return; /* event channel isn't initialized yet */
+	ze->ze_zevent = ev;
+	list_insert_head(&ev->ev_ze_list, ze);
+	nvlist_dup(ev->ev_nvl, event, KM_SLEEP);
+	*dropped = ze->ze_dropped;
+	ze->ze_dropped = 0;
+out:
+	mutex_exit(&zevent_lock);
 
-	while ((sep = sysevent_evc_walk_step(chq)) != NULL) {
-		if ((buf = sysevent_evc_event_attr(sep, &len)) == NULL)
-			break;
+	return error;
+}
+
+int
+zfs_zevent_wait(zfs_zevent_t *ze)
+{
+	int error = 0;
+
+	mutex_enter(&zevent_lock);
 
-		ed.ed_magic = ERPT_MAGIC;
-		ed.ed_chksum = checksum32(buf, len);
-		ed.ed_size = (uint32_t)len;
-		ed.ed_pad = 0;
-		ed.ed_hrt_nsec = SE_TIME(sep);
-		ed.ed_hrt_base = now;
-		ed.ed_tod_base.sec = tod.tv_sec;
-		ed.ed_tod_base.nsec = tod.tv_nsec;
-
-		dumpvp_write(&ed, sizeof (ed));
-		dumpvp_write(buf, len);
+	if (zevent_flags & ZEVENT_SHUTDOWN) {
+		error = ESHUTDOWN;
+		goto out;
 	}
 
-	sysevent_evc_walk_fini(chq);
+	zevent_waiters++;
+	cv_wait_interruptible(&zevent_cv, &zevent_lock);
+	if (issig(JUSTLOOKING))
+		error = EINTR;
+
+	zevent_waiters--;
+out:
+	mutex_exit(&zevent_lock);
+
+	return error;
 }
 
-/*
- * Post an error report (ereport) to the sysevent error channel.  The error
- * channel must be established with a prior call to sysevent_evc_create()
- * before publication may occur.
- */
 void
-fm_ereport_post(nvlist_t *ereport, int evc_flag)
+zfs_zevent_init(zfs_zevent_t **zep)
 {
-	size_t nvl_size = 0;
-	evchan_t *error_chan;
+	zfs_zevent_t *ze;
 
-	(void) nvlist_size(ereport, &nvl_size, NV_ENCODE_NATIVE);
-	if (nvl_size > ERPT_DATA_SZ || nvl_size == 0) {
-		atomic_add_64(&erpt_kstat_data.erpt_dropped.value.ui64, 1);
-		return;
-	}
+	ze = *zep = kmem_zalloc(sizeof (zfs_zevent_t), KM_SLEEP);
+	list_link_init(&ze->ze_node);
+}
 
-	if (sysevent_evc_bind(FM_ERROR_CHAN, &error_chan,
-	    EVCH_CREAT|EVCH_HOLD_PEND) != 0) {
-		atomic_add_64(&erpt_kstat_data.erpt_dropped.value.ui64, 1);
-		return;
-	}
+void
+zfs_zevent_destroy(zfs_zevent_t *ze)
+{
+	mutex_enter(&zevent_lock);
+	if (ze->ze_zevent)
+		list_remove(&ze->ze_zevent->ev_ze_list, ze);
+	mutex_exit(&zevent_lock);
 
-	if (sysevent_evc_publish(error_chan, EC_FM, ESC_FM_ERROR,
-	    SUNW_VENDOR, FM_PUB, ereport, evc_flag) != 0) {
-		atomic_add_64(&erpt_kstat_data.erpt_dropped.value.ui64, 1);
-		(void) sysevent_evc_unbind(error_chan);
-		return;
-	}
-	(void) sysevent_evc_unbind(error_chan);
+	kmem_free(ze, sizeof (zfs_zevent_t));
 }
+#endif /* _KERNEL */
 
 /*
  * Wrapppers for FM nvlist allocators
@@ -938,6 +1054,105 @@ fm_fmri_hc_set(nvlist_t *fmri, int version, const nvlist_t *auth,
 	}
 }
 
+void
+fm_fmri_hc_create(nvlist_t *fmri, int version, const nvlist_t *auth,
+    nvlist_t *snvl, nvlist_t *bboard, int npairs, ...)
+{
+	nv_alloc_t *nva = nvlist_lookup_nv_alloc(fmri);
+	nvlist_t *pairs[HC_MAXPAIRS];
+	nvlist_t **hcl;
+	uint_t n;
+	int i, j;
+	va_list ap;
+	char *hcname, *hcid;
+
+	if (!fm_fmri_hc_set_common(fmri, version, auth))
+		return;
+
+	/*
+	 * copy the bboard nvpairs to the pairs array
+	 */
+	if (nvlist_lookup_nvlist_array(bboard, FM_FMRI_HC_LIST, &hcl, &n)
+	    != 0) {
+		atomic_add_64(&erpt_kstat_data.fmri_set_failed.value.ui64, 1);
+		return;
+	}
+
+	for (i = 0; i < n; i++) {
+		if (nvlist_lookup_string(hcl[i], FM_FMRI_HC_NAME,
+		    &hcname) != 0) {
+			atomic_add_64(
+			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
+			return;
+		}
+		if (nvlist_lookup_string(hcl[i], FM_FMRI_HC_ID, &hcid) != 0) {
+			atomic_add_64(
+			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
+			return;
+		}
+
+		pairs[i] = fm_nvlist_create(nva);
+		if (nvlist_add_string(pairs[i], FM_FMRI_HC_NAME, hcname) != 0 ||
+		    nvlist_add_string(pairs[i], FM_FMRI_HC_ID, hcid) != 0) {
+			for (j = 0; j <= i; j++) {
+				if (pairs[j] != NULL)
+					fm_nvlist_destroy(pairs[j],
+					    FM_NVA_RETAIN);
+			}
+			atomic_add_64(
+			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
+			return;
+		}
+	}
+
+	/*
+	 * create the pairs from passed in pairs
+	 */
+	npairs = MIN(npairs, HC_MAXPAIRS);
+
+	va_start(ap, npairs);
+	for (i = n; i < npairs + n; i++) {
+		const char *name = va_arg(ap, const char *);
+		uint32_t id = va_arg(ap, uint32_t);
+		char idstr[11];
+		(void) snprintf(idstr, sizeof (idstr), "%u", id);
+		pairs[i] = fm_nvlist_create(nva);
+		if (nvlist_add_string(pairs[i], FM_FMRI_HC_NAME, name) != 0 ||
+		    nvlist_add_string(pairs[i], FM_FMRI_HC_ID, idstr) != 0) {
+			for (j = 0; j <= i; j++) {
+				if (pairs[j] != NULL)
+					fm_nvlist_destroy(pairs[j],
+					    FM_NVA_RETAIN);
+			}
+			atomic_add_64(
+			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
+			return;
+		}
+	}
+	va_end(ap);
+
+	/*
+	 * Create the fmri hc list
+	 */
+	if (nvlist_add_nvlist_array(fmri, FM_FMRI_HC_LIST, pairs,
+	    npairs + n) != 0) {
+		atomic_add_64(&erpt_kstat_data.fmri_set_failed.value.ui64, 1);
+		return;
+	}
+
+	for (i = 0; i < npairs + n; i++) {
+			fm_nvlist_destroy(pairs[i], FM_NVA_RETAIN);
+	}
+
+	if (snvl != NULL) {
+		if (nvlist_add_nvlist(fmri, FM_FMRI_HC_SPECIFIC, snvl) != 0) {
+			atomic_add_64(
+			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
+			return;
+		}
+	}
+}
+
 /*
  * Set-up and validate the members of an dev fmri according to:
  *
@@ -1167,7 +1382,7 @@ fm_ena_generate_cpu(uint64_t timestamp, processorid_t cpuid, uchar_t format)
 			ena = (uint64_t)((format & ENA_FORMAT_MASK) |
 			    ((cpuid << ENA_FMT1_CPUID_SHFT) &
 			    ENA_FMT1_CPUID_MASK) |
-			    ((gethrtime_waitfree() << ENA_FMT1_TIME_SHFT) &
+			    ((gethrtime() << ENA_FMT1_TIME_SHFT) &
 			    ENA_FMT1_TIME_MASK));
 		}
 		break;
@@ -1185,7 +1400,7 @@ fm_ena_generate_cpu(uint64_t timestamp, processorid_t cpuid, uchar_t format)
 uint64_t
 fm_ena_generate(uint64_t timestamp, uchar_t format)
 {
-	return (fm_ena_generate_cpu(timestamp, CPU->cpu_id, format));
+	return (fm_ena_generate_cpu(timestamp, getcpuid(), format));
 }
 
 uint64_t
@@ -1253,134 +1468,67 @@ fm_ena_time_get(uint64_t ena)
 	return (time);
 }
 
-/*
- * Convert a getpcstack() trace to symbolic name+offset, and add the resulting
- * string array to a Fault Management ereport as FM_EREPORT_PAYLOAD_NAME_STACK.
- */
+#ifdef _KERNEL
 void
-fm_payload_stack_add(nvlist_t *payload, const pc_t *stack, int depth)
+fm_init(void)
 {
-	int i;
-	char *sym;
-	ulong_t off;
-	char *stkpp[FM_STK_DEPTH];
-	char buf[FM_STK_DEPTH * FM_SYM_SZ];
-	char *stkp = buf;
-
-	for (i = 0; i < depth && i != FM_STK_DEPTH; i++, stkp += FM_SYM_SZ) {
-		if ((sym = kobj_getsymname(stack[i], &off)) != NULL)
-			(void) snprintf(stkp, FM_SYM_SZ, "%s+%lx", sym, off);
-		else
-			(void) snprintf(stkp, FM_SYM_SZ, "%lx", (long)stack[i]);
-		stkpp[i] = stkp;
-	}
+	zevent_len_cur = 0;
+	zevent_flags = 0;
 
-	fm_payload_set(payload, FM_EREPORT_PAYLOAD_NAME_STACK,
-	    DATA_TYPE_STRING_ARRAY, depth, stkpp, NULL);
-}
+	if (zevent_len_max == 0)
+		zevent_len_max = ERPT_MAX_ERRS * MAX(max_ncpus, 4);
 
-void
-print_msg_hwerr(ctid_t ct_id, proc_t *p)
-{
-	uprintf("Killed process %d (%s) in contract id %d "
-	    "due to hardware error\n", p->p_pid, p->p_user.u_comm, ct_id);
+	/* Initialize zevent allocation and generation kstats */
+	fm_ksp = kstat_create("zfs", 0, "fm", "misc", KSTAT_TYPE_NAMED,
+	    sizeof (struct erpt_kstat) / sizeof (kstat_named_t),
+	    KSTAT_FLAG_VIRTUAL);
+
+	if (fm_ksp != NULL) {
+		fm_ksp->ks_data = &erpt_kstat_data;
+		kstat_install(fm_ksp);
+	} else {
+		cmn_err(CE_NOTE, "failed to create fm/misc kstat\n");
+	}
+
+	mutex_init(&zevent_lock, NULL, MUTEX_DEFAULT, NULL);
+	list_create(&zevent_list, sizeof(zevent_t), offsetof(zevent_t, ev_node));
+	cv_init(&zevent_cv, NULL, CV_DEFAULT, NULL);
 }
 
 void
-fm_fmri_hc_create(nvlist_t *fmri, int version, const nvlist_t *auth,
-    nvlist_t *snvl, nvlist_t *bboard, int npairs, ...)
+fm_fini(void)
 {
-	nv_alloc_t *nva = nvlist_lookup_nv_alloc(fmri);
-	nvlist_t *pairs[HC_MAXPAIRS];
-	nvlist_t **hcl;
-	uint_t n;
-	int i, j;
-	va_list ap;
-	char *hcname, *hcid;
+	int count;
 
-	if (!fm_fmri_hc_set_common(fmri, version, auth))
-		return;
+	zfs_zevent_drain_all(&count);
+	cv_broadcast(&zevent_cv);
 
-	/*
-	 * copy the bboard nvpairs to the pairs array
-	 */
-	if (nvlist_lookup_nvlist_array(bboard, FM_FMRI_HC_LIST, &hcl, &n)
-	    != 0) {
-		atomic_add_64(&erpt_kstat_data.fmri_set_failed.value.ui64, 1);
-		return;
+	mutex_enter(&zevent_lock);
+	zevent_flags |= ZEVENT_SHUTDOWN;
+	while (zevent_waiters > 0) {
+		mutex_exit(&zevent_lock);
+		schedule();
+		mutex_enter(&zevent_lock);
 	}
+	mutex_exit(&zevent_lock);
 
-	for (i = 0; i < n; i++) {
-		if (nvlist_lookup_string(hcl[i], FM_FMRI_HC_NAME,
-		    &hcname) != 0) {
-			atomic_add_64(
-			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
-			return;
-		}
-		if (nvlist_lookup_string(hcl[i], FM_FMRI_HC_ID, &hcid) != 0) {
-			atomic_add_64(
-			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
-			return;
-		}
+	cv_destroy(&zevent_cv);
+	list_destroy(&zevent_list);
+	mutex_destroy(&zevent_lock);
 
-		pairs[i] = fm_nvlist_create(nva);
-		if (nvlist_add_string(pairs[i], FM_FMRI_HC_NAME, hcname) != 0 ||
-		    nvlist_add_string(pairs[i], FM_FMRI_HC_ID, hcid) != 0) {
-			for (j = 0; j <= i; j++) {
-				if (pairs[j] != NULL)
-					fm_nvlist_destroy(pairs[j],
-					    FM_NVA_RETAIN);
-			}
-			atomic_add_64(
-			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
-			return;
-		}
+	if (fm_ksp != NULL) {
+		kstat_delete(fm_ksp);
+		fm_ksp = NULL;
 	}
+}
 
-	/*
-	 * create the pairs from passed in pairs
-	 */
-	npairs = MIN(npairs, HC_MAXPAIRS);
-
-	va_start(ap, npairs);
-	for (i = n; i < npairs + n; i++) {
-		const char *name = va_arg(ap, const char *);
-		uint32_t id = va_arg(ap, uint32_t);
-		char idstr[11];
-		(void) snprintf(idstr, sizeof (idstr), "%u", id);
-		pairs[i] = fm_nvlist_create(nva);
-		if (nvlist_add_string(pairs[i], FM_FMRI_HC_NAME, name) != 0 ||
-		    nvlist_add_string(pairs[i], FM_FMRI_HC_ID, idstr) != 0) {
-			for (j = 0; j <= i; j++) {
-				if (pairs[j] != NULL)
-					fm_nvlist_destroy(pairs[j],
-					    FM_NVA_RETAIN);
-			}
-			atomic_add_64(
-			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
-			return;
-		}
-	}
-	va_end(ap);
+module_param(zevent_len_max, int, 0644);
+MODULE_PARM_DESC(zevent_len_max, "Maximum event queue length");
 
-	/*
-	 * Create the fmri hc list
-	 */
-	if (nvlist_add_nvlist_array(fmri, FM_FMRI_HC_LIST, pairs,
-	    npairs + n) != 0) {
-		atomic_add_64(&erpt_kstat_data.fmri_set_failed.value.ui64, 1);
-		return;
-	}
+module_param(zevent_cols, int, 0644);
+MODULE_PARM_DESC(zevent_cols, "Maximum event column width");
 
-	for (i = 0; i < npairs + n; i++) {
-			fm_nvlist_destroy(pairs[i], FM_NVA_RETAIN);
-	}
+module_param(zevent_console, int, 0644);
+MODULE_PARM_DESC(zevent_console, "Log events to the console");
 
-	if (snvl != NULL) {
-		if (nvlist_add_nvlist(fmri, FM_FMRI_HC_SPECIFIC, snvl) != 0) {
-			atomic_add_64(
-			    &erpt_kstat_data.fmri_set_failed.value.ui64, 1);
-			return;
-		}
-	}
-}
+#endif /* _KERNEL */