Add slow disk diagnosis to ZED

Slow disk response times can be indicative of a failing drive. ZFS
currently tracks slow I/Os (slower than zio_slow_io_ms) and generates
events (ereport.fs.zfs.delay).  However, no action is taken by ZED,
like is done for checksum or I/O errors.  This change adds slow disk
diagnosis to ZED which is opt-in using new VDEV properties:
  VDEV_PROP_SLOW_IO_N
  VDEV_PROP_SLOW_IO_T

If multiple VDEVs in a pool are undergoing slow I/Os, then it skips
the zpool_vdev_degrade().

Sponsored-By: OpenDrives Inc.
Sponsored-By: Klara Inc.
Co-authored-by: Rob Wing <rob.wing@klarasystems.com>
Signed-off-by: Don Brady <don.brady@klarasystems.com>

cmd/zed/agents/fmd_api.c

@@ -22,6 +22,7 @@
  * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
  *
  * Copyright (c) 2016, Intel Corporation.
+ * Copyright (c) 2023, Klara Inc.
  */
 
 /*
@@ -231,28 +232,6 @@ fmd_prop_get_int32(fmd_hdl_t *hdl, const char *name)
 	if (strcmp(name, "spare_on_remove") == 0)
 		return (1);
 
-	if (strcmp(name, "io_N") == 0 || strcmp(name, "checksum_N") == 0)
-		return (10);	/* N = 10 events */
-
-	return (0);
-}
-
-int64_t
-fmd_prop_get_int64(fmd_hdl_t *hdl, const char *name)
-{
-	(void) hdl;
-
-	/*
-	 * These can be looked up in mp->modinfo->fmdi_props
-	 * For now we just hard code for phase 2. In the
-	 * future, there can be a ZED based override.
-	 */
-	if (strcmp(name, "remove_timeout") == 0)
-		return (15ULL * 1000ULL * 1000ULL * 1000ULL);	/* 15 sec */
-
-	if (strcmp(name, "io_T") == 0 || strcmp(name, "checksum_T") == 0)
-		return (1000ULL * 1000ULL * 1000ULL * 600ULL);	/* 10 min */
-
 	return (0);
 }
 
@@ -535,37 +514,53 @@ fmd_serd_exists(fmd_hdl_t *hdl, const char *name)
 	return (fmd_serd_eng_lookup(&mp->mod_serds, name) != NULL);
 }
 
-void
-fmd_serd_reset(fmd_hdl_t *hdl, const char *name)
+int
+fmd_serd_active(fmd_hdl_t *hdl, const char *name)
 {
 	fmd_module_t *mp = (fmd_module_t *)hdl;
 	fmd_serd_eng_t *sgp;
 
 	if ((sgp = fmd_serd_eng_lookup(&mp->mod_serds, name)) == NULL) {
 		zed_log_msg(LOG_ERR, "serd engine '%s' does not exist", name);
-		return;
+		return (0);
 	}
+	return (fmd_serd_eng_fired(sgp) || !fmd_serd_eng_empty(sgp));
+}
 
-	fmd_serd_eng_reset(sgp);
+void
+fmd_serd_reset(fmd_hdl_t *hdl, const char *name)
+{
+	fmd_module_t *mp = (fmd_module_t *)hdl;
+	fmd_serd_eng_t *sgp;
 
-	fmd_hdl_debug(hdl, "serd_reset %s", name);
+	if ((sgp = fmd_serd_eng_lookup(&mp->mod_serds, name)) == NULL) {
+		zed_log_msg(LOG_ERR, "serd engine '%s' does not exist", name);
+	} else {
+		fmd_serd_eng_reset(sgp);
+		fmd_hdl_debug(hdl, "serd_reset %s", name);
+	}
 }
 
 int
 fmd_serd_record(fmd_hdl_t *hdl, const char *name, fmd_event_t *ep)
 {
 	fmd_module_t *mp = (fmd_module_t *)hdl;
 	fmd_serd_eng_t *sgp;
-	int err;
 
 	if ((sgp = fmd_serd_eng_lookup(&mp->mod_serds, name)) == NULL) {
 		zed_log_msg(LOG_ERR, "failed to add record to SERD engine '%s'",
 		    name);
 		return (0);
 	}
-	err = fmd_serd_eng_record(sgp, ep->ev_hrt);
+	return (fmd_serd_eng_record(sgp, ep->ev_hrt));
+}
+
+void
+fmd_serd_gc(fmd_hdl_t *hdl)
+{
+	fmd_module_t *mp = (fmd_module_t *)hdl;
 
-	return (err);
+	fmd_serd_hash_apply(&mp->mod_serds, fmd_serd_eng_gc, NULL);
 }
 
 /* FMD Timers */
@@ -579,7 +574,7 @@ _timer_notify(union sigval sv)
 	const fmd_hdl_ops_t *ops = mp->mod_info->fmdi_ops;
 	struct itimerspec its;
 
-	fmd_hdl_debug(hdl, "timer fired (%p)", ftp->ft_tid);
+	fmd_hdl_debug(hdl, "%s timer fired (%p)", mp->mod_name, ftp->ft_tid);
 
 	/* disarm the timer */
 	memset(&its, 0, sizeof (struct itimerspec));

cmd/zed/agents/fmd_api.h

@@ -151,7 +151,6 @@ extern void fmd_hdl_vdebug(fmd_hdl_t *, const char *, va_list);
 extern void fmd_hdl_debug(fmd_hdl_t *, const char *, ...);
 
 extern int32_t fmd_prop_get_int32(fmd_hdl_t *, const char *);
-extern int64_t fmd_prop_get_int64(fmd_hdl_t *, const char *);
 
 #define	FMD_STAT_NOALLOC	0x0	/* fmd should use caller's memory */
 #define	FMD_STAT_ALLOC		0x1	/* fmd should allocate stats memory */
@@ -195,10 +194,12 @@ extern size_t fmd_buf_size(fmd_hdl_t *, fmd_case_t *, const char *);
 extern void fmd_serd_create(fmd_hdl_t *, const char *, uint_t, hrtime_t);
 extern void fmd_serd_destroy(fmd_hdl_t *, const char *);
 extern int fmd_serd_exists(fmd_hdl_t *, const char *);
+extern int fmd_serd_active(fmd_hdl_t *, const char *);
 extern void fmd_serd_reset(fmd_hdl_t *, const char *);
 extern int fmd_serd_record(fmd_hdl_t *, const char *, fmd_event_t *);
 extern int fmd_serd_fired(fmd_hdl_t *, const char *);
 extern int fmd_serd_empty(fmd_hdl_t *, const char *);
+extern void fmd_serd_gc(fmd_hdl_t *);
 
 extern id_t fmd_timer_install(fmd_hdl_t *, void *, fmd_event_t *, hrtime_t);
 extern void fmd_timer_remove(fmd_hdl_t *, id_t);

cmd/zed/agents/fmd_serd.c

@@ -310,8 +310,9 @@ fmd_serd_eng_reset(fmd_serd_eng_t *sgp)
 }
 
 void
-fmd_serd_eng_gc(fmd_serd_eng_t *sgp)
+fmd_serd_eng_gc(fmd_serd_eng_t *sgp, void *arg)
 {
+	(void) arg;
 	fmd_serd_elem_t *sep, *nep;
 	hrtime_t hrt;
 

cmd/zed/agents/fmd_serd.h

@@ -77,7 +77,7 @@ extern int fmd_serd_eng_fired(fmd_serd_eng_t *);
 extern int fmd_serd_eng_empty(fmd_serd_eng_t *);
 
 extern void fmd_serd_eng_reset(fmd_serd_eng_t *);
-extern void fmd_serd_eng_gc(fmd_serd_eng_t *);
+extern void fmd_serd_eng_gc(fmd_serd_eng_t *, void *);
 
 #ifdef	__cplusplus
 }