diff --git a/cddl/lib/libzpool/Makefile b/cddl/lib/libzpool/Makefile
index d9b2e67094e3..6893e31ff20a 100644
--- a/cddl/lib/libzpool/Makefile
+++ b/cddl/lib/libzpool/Makefile
@@ -162,6 +162,7 @@ KERNEL_C = \
 	zfs_fuid.c \
 	zfs_sa.c \
 	zfs_znode.c \
+	zfs_racct.c \
 	zfs_ratelimit.c \
 	zfs_rlock.c \
 	zil.c \
diff --git a/stand/libsa/zfs/zstd_shim.c b/stand/libsa/zfs/zstd_shim.c
index b94df6f51913..91f5171a72b5 100644
--- a/stand/libsa/zfs/zstd_shim.c
+++ b/stand/libsa/zfs/zstd_shim.c
@@ -37,4 +37,9 @@ __FBSDID("$FreeBSD$");
 #define ZFS_MODULE_PARAM_ARGS void
 typedef int boolean_t;	/* This one may be tough to get rid of */
 
+/* TODO: openzfs/include/sys/uio_impl.h must not be included */
+#ifndef _SYS_UIO_IMPL_H
+#define _SYS_UIO_IMPL_H
+#endif
+
 #include <contrib/openzfs/module/zstd/zfs_zstd.c>
diff --git a/sys/contrib/openzfs/cmd/zfs/zfs_main.c b/sys/contrib/openzfs/cmd/zfs/zfs_main.c
index ab2b006ae460..9a59fddbf06d 100644
--- a/sys/contrib/openzfs/cmd/zfs/zfs_main.c
+++ b/sys/contrib/openzfs/cmd/zfs/zfs_main.c
@@ -6912,9 +6912,6 @@ report_mount_progress(int current, int total)
 	time_t now = time(NULL);
 	char info[32];
 
-	/* report 1..n instead of 0..n-1 */
-	++current;
-
 	/* display header if we're here for the first time */
 	if (current == 1) {
 		set_progress_header(gettext("Mounting ZFS filesystems"));
diff --git a/sys/contrib/openzfs/cmd/ztest/ztest.c b/sys/contrib/openzfs/cmd/ztest/ztest.c
index d2bf0101993e..cfa1290d78d1 100644
--- a/sys/contrib/openzfs/cmd/ztest/ztest.c
+++ b/sys/contrib/openzfs/cmd/ztest/ztest.c
@@ -158,6 +158,9 @@ enum ztest_class_state {
 	ZTEST_VDEV_CLASS_RND
 };
 
+#define	ZO_GVARS_MAX_ARGLEN	((size_t)64)
+#define	ZO_GVARS_MAX_COUNT	((size_t)10)
+
 typedef struct ztest_shared_opts {
 	char zo_pool[ZFS_MAX_DATASET_NAME_LEN];
 	char zo_dir[ZFS_MAX_DATASET_NAME_LEN];
@@ -185,6 +188,8 @@ typedef struct ztest_shared_opts {
 	int zo_mmp_test;
 	int zo_special_vdevs;
 	int zo_dump_dbgmsg;
+	int zo_gvars_count;
+	char zo_gvars[ZO_GVARS_MAX_COUNT][ZO_GVARS_MAX_ARGLEN];
 } ztest_shared_opts_t;
 
 static const ztest_shared_opts_t ztest_opts_defaults = {
@@ -212,6 +217,7 @@ static const ztest_shared_opts_t ztest_opts_defaults = {
 	.zo_maxloops = 50,		/* max loops during spa_freeze() */
 	.zo_metaslab_force_ganging = 64 << 10,
 	.zo_special_vdevs = ZTEST_VDEV_CLASS_RND,
+	.zo_gvars_count = 0,
 };
 
 extern uint64_t metaslab_force_ganging;
@@ -918,8 +924,21 @@ process_options(int argc, char **argv)
 			ztest_parse_name_value(optarg, zo);
 			break;
 		case 'o':
-			if (set_global_var(optarg) != 0)
+			if (zo->zo_gvars_count >= ZO_GVARS_MAX_COUNT) {
+				(void) fprintf(stderr,
+				    "max global var count (%zu) exceeded\n",
+				    ZO_GVARS_MAX_COUNT);
 				usage(B_FALSE);
+			}
+			char *v = zo->zo_gvars[zo->zo_gvars_count];
+			if (strlcpy(v, optarg, ZO_GVARS_MAX_ARGLEN) >=
+			    ZO_GVARS_MAX_ARGLEN) {
+				(void) fprintf(stderr,
+				    "global var option '%s' is too long\n",
+				    optarg);
+				usage(B_FALSE);
+			}
+			zo->zo_gvars_count++;
 			break;
 		case 'G':
 			zo->zo_dump_dbgmsg = 1;
@@ -6373,6 +6392,75 @@ ztest_fletcher_incr(ztest_ds_t *zd, uint64_t id)
 	}
 }
 
+static int
+ztest_set_global_vars(void)
+{
+	for (size_t i = 0; i < ztest_opts.zo_gvars_count; i++) {
+		char *kv = ztest_opts.zo_gvars[i];
+		VERIFY3U(strlen(kv), <=, ZO_GVARS_MAX_ARGLEN);
+		VERIFY3U(strlen(kv), >, 0);
+		int err = set_global_var(kv);
+		if (ztest_opts.zo_verbose > 0) {
+			(void) printf("setting global var %s ... %s\n", kv,
+			    err ? "failed" : "ok");
+		}
+		if (err != 0) {
+			(void) fprintf(stderr,
+			    "failed to set global var '%s'\n", kv);
+			return (err);
+		}
+	}
+	return (0);
+}
+
+static char **
+ztest_global_vars_to_zdb_args(void)
+{
+	char **args = calloc(2*ztest_opts.zo_gvars_count + 1, sizeof (char *));
+	char **cur = args;
+	for (size_t i = 0; i < ztest_opts.zo_gvars_count; i++) {
+		char *kv = ztest_opts.zo_gvars[i];
+		*cur = "-o";
+		cur++;
+		*cur = strdup(kv);
+		cur++;
+	}
+	ASSERT3P(cur, ==, &args[2*ztest_opts.zo_gvars_count]);
+	*cur = NULL;
+	return (args);
+}
+
+/* The end of strings is indicated by a NULL element */
+static char *
+join_strings(char **strings, const char *sep)
+{
+	size_t totallen = 0;
+	for (char **sp = strings; *sp != NULL; sp++) {
+		totallen += strlen(*sp);
+		totallen += strlen(sep);
+	}
+	if (totallen > 0) {
+		ASSERT(totallen >= strlen(sep));
+		totallen -= strlen(sep);
+	}
+
+	size_t buflen = totallen + 1;
+	char *o = malloc(buflen); /* trailing 0 byte */
+	o[0] = '\0';
+	for (char **sp = strings; *sp != NULL; sp++) {
+		size_t would;
+		would = strlcat(o, *sp, buflen);
+		VERIFY3U(would, <, buflen);
+		if (*(sp+1) == NULL) {
+			break;
+		}
+		would = strlcat(o, sep, buflen);
+		VERIFY3U(would, <, buflen);
+	}
+	ASSERT3S(strlen(o), ==, totallen);
+	return (o);
+}
+
 static int
 ztest_check_path(char *path)
 {
@@ -6601,13 +6689,21 @@ ztest_run_zdb(char *pool)
 
 	ztest_get_zdb_bin(bin, len);
 
-	(void) sprintf(zdb,
-	    "%s -bcc%s%s -G -d -Y -e -y -p %s %s",
+	char **set_gvars_args = ztest_global_vars_to_zdb_args();
+	char *set_gvars_args_joined = join_strings(set_gvars_args, " ");
+	free(set_gvars_args);
+
+	size_t would = snprintf(zdb, len,
+	    "%s -bcc%s%s -G -d -Y -e -y %s -p %s %s",
 	    bin,
 	    ztest_opts.zo_verbose >= 3 ? "s" : "",
 	    ztest_opts.zo_verbose >= 4 ? "v" : "",
+	    set_gvars_args_joined,
 	    ztest_opts.zo_dir,
 	    pool);
+	ASSERT3U(would, <, len);
+
+	free(set_gvars_args_joined);
 
 	if (ztest_opts.zo_verbose >= 5)
 		(void) printf("Executing %s\n", strstr(zdb, "zdb "));
@@ -7727,7 +7823,7 @@ main(int argc, char **argv)
 	char numbuf[NN_NUMBUF_SZ];
 	char *cmd;
 	boolean_t hasalt;
-	int f;
+	int f, err;
 	char *fd_data_str = getenv("ZTEST_FD_DATA");
 	struct sigaction action;
 
@@ -7794,6 +7890,15 @@ main(int argc, char **argv)
 	}
 	ASSERT3U(ztest_opts.zo_datasets, ==, ztest_shared_hdr->zh_ds_count);
 
+	err = ztest_set_global_vars();
+	if (err != 0 && !fd_data_str) {
+		/* error message done by ztest_set_global_vars */
+		exit(EXIT_FAILURE);
+	} else {
+		/* children should not be spawned if setting gvars fails */
+		VERIFY3S(err, ==, 0);
+	}
+
 	/* Override location of zpool.cache */
 	VERIFY3S(asprintf((char **)&spa_config_path, "%s/zpool.cache",
 	    ztest_opts.zo_dir), !=, -1);
diff --git a/sys/contrib/openzfs/include/os/freebsd/spl/sys/uio.h b/sys/contrib/openzfs/include/os/freebsd/spl/sys/uio.h
index f1d30195f048..b71f2f2e5625 100644
--- a/sys/contrib/openzfs/include/os/freebsd/spl/sys/uio.h
+++ b/sys/contrib/openzfs/include/os/freebsd/spl/sys/uio.h
@@ -55,38 +55,12 @@ typedef struct zfs_uio {
 #define	zfs_uio_fault_disable(u, set)
 #define	zfs_uio_prefaultpages(size, u)	(0)
 
-
-static __inline void
-zfs_uio_init(zfs_uio_t *uio, struct uio *uio_s)
-{
-	GET_UIO_STRUCT(uio) = uio_s;
-}
-
-static __inline void
+static inline void
 zfs_uio_setoffset(zfs_uio_t *uio, offset_t off)
 {
 	zfs_uio_offset(uio) = off;
 }
 
-static __inline int
-zfs_uiomove(void *cp, size_t n, zfs_uio_rw_t dir, zfs_uio_t *uio)
-{
-	ASSERT(zfs_uio_rw(uio) == dir);
-	return (uiomove(cp, (int)n, GET_UIO_STRUCT(uio)));
-}
-
-int zfs_uiocopy(void *p, size_t n, zfs_uio_rw_t rw, zfs_uio_t *uio,
-    size_t *cbytes);
-void zfs_uioskip(zfs_uio_t *uiop, size_t n);
-int zfs_uio_fault_move(void *p, size_t n, zfs_uio_rw_t dir, zfs_uio_t *uio);
-
-static inline void
-zfs_uio_iov_at_index(zfs_uio_t *uio, uint_t idx, void **base, uint64_t *len)
-{
-	*base = zfs_uio_iovbase(uio, idx);
-	*len = zfs_uio_iovlen(uio, idx);
-}
-
 static inline void
 zfs_uio_advance(zfs_uio_t *uio, size_t size)
 {
@@ -94,19 +68,14 @@ zfs_uio_advance(zfs_uio_t *uio, size_t size)
 	zfs_uio_offset(uio) += size;
 }
 
-static inline offset_t
-zfs_uio_index_at_offset(zfs_uio_t *uio, offset_t off, uint_t *vec_idx)
+static __inline void
+zfs_uio_init(zfs_uio_t *uio, struct uio *uio_s)
 {
-	*vec_idx = 0;
-	while (*vec_idx < zfs_uio_iovcnt(uio) &&
-	    off >= zfs_uio_iovlen(uio, *vec_idx)) {
-		off -= zfs_uio_iovlen(uio, *vec_idx);
-		(*vec_idx)++;
-	}
-
-	return (off);
+	GET_UIO_STRUCT(uio) = uio_s;
 }
 
+int zfs_uio_fault_move(void *p, size_t n, zfs_uio_rw_t dir, zfs_uio_t *uio);
+
 #endif /* !_STANDALONE */
 
 #endif	/* !_OPENSOLARIS_SYS_UIO_H_ */
diff --git a/sys/contrib/openzfs/include/os/linux/spl/sys/uio.h b/sys/contrib/openzfs/include/os/linux/spl/sys/uio.h
index 0deed3c5736d..66af2b0b534c 100644
--- a/sys/contrib/openzfs/include/os/linux/spl/sys/uio.h
+++ b/sys/contrib/openzfs/include/os/linux/spl/sys/uio.h
@@ -78,19 +78,14 @@ typedef struct zfs_uio {
 #define	zfs_uio_rlimit_fsize(z, u)	(0)
 #define	zfs_uio_fault_move(p, n, rw, u)	zfs_uiomove((p), (n), (rw), (u))
 
+extern int zfs_uio_prefaultpages(ssize_t, zfs_uio_t *);
+
 static inline void
 zfs_uio_setoffset(zfs_uio_t *uio, offset_t off)
 {
 	uio->uio_loffset = off;
 }
 
-static inline void
-zfs_uio_iov_at_index(zfs_uio_t *uio, uint_t idx, void **base, uint64_t *len)
-{
-	*base = zfs_uio_iovbase(uio, idx);
-	*len = zfs_uio_iovlen(uio, idx);
-}
-
 static inline void
 zfs_uio_advance(zfs_uio_t *uio, size_t size)
 {
@@ -98,19 +93,6 @@ zfs_uio_advance(zfs_uio_t *uio, size_t size)
 	uio->uio_loffset += size;
 }
 
-static inline offset_t
-zfs_uio_index_at_offset(zfs_uio_t *uio, offset_t off, uint_t *vec_idx)
-{
-	*vec_idx = 0;
-	while (*vec_idx < zfs_uio_iovcnt(uio) &&
-	    off >= zfs_uio_iovlen(uio, *vec_idx)) {
-		off -= zfs_uio_iovlen(uio, *vec_idx);
-		(*vec_idx)++;
-	}
-
-	return (off);
-}
-
 static inline void
 zfs_uio_iovec_init(zfs_uio_t *uio, const struct iovec *iov,
     unsigned long nr_segs, offset_t offset, zfs_uio_seg_t seg, ssize_t resid,
diff --git a/sys/contrib/openzfs/include/os/linux/zfs/sys/zfs_context_os.h b/sys/contrib/openzfs/include/os/linux/zfs/sys/zfs_context_os.h
index 9e5fdd79f019..de7015b929b6 100644
--- a/sys/contrib/openzfs/include/os/linux/zfs/sys/zfs_context_os.h
+++ b/sys/contrib/openzfs/include/os/linux/zfs/sys/zfs_context_os.h
@@ -23,7 +23,6 @@
 #ifndef ZFS_CONTEXT_OS_H
 #define	ZFS_CONTEXT_OS_H
 
-#include <sys/uio_impl.h>
 #include <linux/dcache_compat.h>
 #include <linux/utsname_compat.h>
 
diff --git a/sys/contrib/openzfs/include/sys/Makefile.am b/sys/contrib/openzfs/include/sys/Makefile.am
index c3ebf17b5288..385c82c926ae 100644
--- a/sys/contrib/openzfs/include/sys/Makefile.am
+++ b/sys/contrib/openzfs/include/sys/Makefile.am
@@ -111,6 +111,7 @@ COMMON_H = \
 	zfs_fuid.h \
 	zfs_project.h \
 	zfs_quota.h \
+	zfs_racct.h \
 	zfs_ratelimit.h \
 	zfs_refcount.h \
 	zfs_rlock.h \
diff --git a/sys/contrib/openzfs/include/sys/spa.h b/sys/contrib/openzfs/include/sys/spa.h
index 0762ae8a3e13..8391be8328b6 100644
--- a/sys/contrib/openzfs/include/sys/spa.h
+++ b/sys/contrib/openzfs/include/sys/spa.h
@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011, 2020 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2021 by Delphix. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
  * Copyright 2013 Saso Kiselkov. All rights reserved.
@@ -1150,6 +1150,7 @@ extern int zfs_ereport_post(const char *clazz, spa_t *spa, vdev_t *vd,
 extern boolean_t zfs_ereport_is_valid(const char *clazz, spa_t *spa, vdev_t *vd,
     zio_t *zio);
 extern void zfs_ereport_taskq_fini(void);
+extern void zfs_ereport_clear(spa_t *spa, vdev_t *vd);
 extern nvlist_t *zfs_event_create(spa_t *spa, vdev_t *vd, const char *type,
     const char *name, nvlist_t *aux);
 extern void zfs_post_remove(spa_t *spa, vdev_t *vd);
diff --git a/sys/contrib/openzfs/include/sys/uio_impl.h b/sys/contrib/openzfs/include/sys/uio_impl.h
index be70cea54818..cde3ef40485b 100644
--- a/sys/contrib/openzfs/include/sys/uio_impl.h
+++ b/sys/contrib/openzfs/include/sys/uio_impl.h
@@ -42,8 +42,27 @@
 #include <sys/uio.h>
 
 extern int zfs_uiomove(void *, size_t, zfs_uio_rw_t, zfs_uio_t *);
-extern int zfs_uio_prefaultpages(ssize_t, zfs_uio_t *);
 extern int zfs_uiocopy(void *, size_t, zfs_uio_rw_t, zfs_uio_t *, size_t *);
 extern void zfs_uioskip(zfs_uio_t *, size_t);
 
+static inline void
+zfs_uio_iov_at_index(zfs_uio_t *uio, uint_t idx, void **base, uint64_t *len)
+{
+	*base = zfs_uio_iovbase(uio, idx);
+	*len = zfs_uio_iovlen(uio, idx);
+}
+
+static inline offset_t
+zfs_uio_index_at_offset(zfs_uio_t *uio, offset_t off, uint_t *vec_idx)
+{
+	*vec_idx = 0;
+	while (*vec_idx < zfs_uio_iovcnt(uio) &&
+	    off >= zfs_uio_iovlen(uio, *vec_idx)) {
+		off -= zfs_uio_iovlen(uio, *vec_idx);
+		(*vec_idx)++;
+	}
+
+	return (off);
+}
+
 #endif	/* _SYS_UIO_IMPL_H */
diff --git a/sys/contrib/openzfs/include/sys/zfs_context.h b/sys/contrib/openzfs/include/sys/zfs_context.h
index ee3216d6763a..6cdcc6d30966 100644
--- a/sys/contrib/openzfs/include/sys/zfs_context.h
+++ b/sys/contrib/openzfs/include/sys/zfs_context.h
@@ -72,6 +72,7 @@ extern "C" {
 #include <sys/trace.h>
 #include <sys/procfs_list.h>
 #include <sys/mod.h>
+#include <sys/uio_impl.h>
 #include <sys/zfs_context_os.h>
 #else /* _KERNEL || _STANDALONE */
 
@@ -652,7 +653,7 @@ extern void random_fini(void);
 
 struct spa;
 extern void show_pool_stats(struct spa *);
-extern int set_global_var(char *arg);
+extern int set_global_var(char const *arg);
 
 typedef struct callb_cpr {
 	kmutex_t	*cc_lockp;
diff --git a/sys/contrib/openzfs/include/sys/zfs_racct.h b/sys/contrib/openzfs/include/sys/zfs_racct.h
new file mode 100644
index 000000000000..cfcdd336ea42
--- /dev/null
+++ b/sys/contrib/openzfs/include/sys/zfs_racct.h
@@ -0,0 +1,37 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Portions Copyright 2021 iXsystems, Inc.
+ */
+
+#ifndef _SYS_ZFS_RACCT_H
+#define	_SYS_ZFS_RACCT_H
+
+#include <sys/zfs_context.h>
+
+/*
+ * Platform-dependent resource accounting hooks
+ */
+void zfs_racct_read(uint64_t size, uint64_t iops);
+void zfs_racct_write(uint64_t size, uint64_t iops);
+
+#endif /* _SYS_ZFS_RACCT_H */
diff --git a/sys/contrib/openzfs/lib/libzpool/Makefile.am b/sys/contrib/openzfs/lib/libzpool/Makefile.am
index 04ef34ebfa1b..929f5bed8b2f 100644
--- a/sys/contrib/openzfs/lib/libzpool/Makefile.am
+++ b/sys/contrib/openzfs/lib/libzpool/Makefile.am
@@ -163,6 +163,7 @@ KERNEL_C = \
 	zfs_debug.c \
 	zfs_fm.c \
 	zfs_fuid.c \
+	zfs_racct.c \
 	zfs_sa.c \
 	zfs_znode.c \
 	zfs_ratelimit.c \
diff --git a/sys/contrib/openzfs/lib/libzpool/util.c b/sys/contrib/openzfs/lib/libzpool/util.c
index ebfaa9b41a2a..2da2375a1d2d 100644
--- a/sys/contrib/openzfs/lib/libzpool/util.c
+++ b/sys/contrib/openzfs/lib/libzpool/util.c
@@ -148,18 +148,54 @@ show_pool_stats(spa_t *spa)
 	nvlist_free(config);
 }
 
+/* *k_out must be freed by the caller */
+static int
+set_global_var_parse_kv(const char *arg, char **k_out, u_longlong_t *v_out)
+{
+	int err;
+	VERIFY(arg);
+	char *d = strdup(arg);
+
+	char *save = NULL;
+	char *k = strtok_r(d, "=", &save);
+	char *v_str = strtok_r(NULL, "=", &save);
+	char *follow = strtok_r(NULL, "=", &save);
+	if (k == NULL || v_str == NULL || follow != NULL) {
+		err = EINVAL;
+		goto err_free;
+	}
+
+	u_longlong_t val = strtoull(v_str, NULL, 0);
+	if (val > UINT32_MAX) {
+		fprintf(stderr, "Value for global variable '%s' must "
+		    "be a 32-bit unsigned integer, got '%s'\n", k, v_str);
+		err = EOVERFLOW;
+		goto err_free;
+	}
+
+	*k_out = k;
+	*v_out = val;
+	return (0);
+
+err_free:
+	free(k);
+
+	return (err);
+}
+
 /*
  * Sets given global variable in libzpool to given unsigned 32-bit value.
  * arg: "<variable>=<value>"
  */
 int
-set_global_var(char *arg)
+set_global_var(char const *arg)
 {
 	void *zpoolhdl;
-	char *varname = arg, *varval;
+	char *varname;
 	u_longlong_t val;
+	int ret;
 
-#ifndef _LITTLE_ENDIAN
+#ifndef _ZFS_LITTLE_ENDIAN
 	/*
 	 * On big endian systems changing a 64-bit variable would set the high
 	 * 32 bits instead of the low 32 bits, which could cause unexpected
@@ -167,19 +203,12 @@ set_global_var(char *arg)
 	 */
 	fprintf(stderr, "Setting global variables is only supported on "
 	    "little-endian systems\n");
-	return (ENOTSUP);
+	ret = ENOTSUP;
+	goto out_ret;
 #endif
-	if (arg != NULL && (varval = strchr(arg, '=')) != NULL) {
-		*varval = '\0';
-		varval++;
-		val = strtoull(varval, NULL, 0);
-		if (val > UINT32_MAX) {
-			fprintf(stderr, "Value for global variable '%s' must "
-			    "be a 32-bit unsigned integer\n", varname);
-			return (EOVERFLOW);
-		}
-	} else {
-		return (EINVAL);
+
+	if ((ret = set_global_var_parse_kv(arg, &varname, &val)) != 0) {
+		goto out_ret;
 	}
 
 	zpoolhdl = dlopen("libzpool.so", RTLD_LAZY);
@@ -189,18 +218,25 @@ set_global_var(char *arg)
 		if (var == NULL) {
 			fprintf(stderr, "Global variable '%s' does not exist "
 			    "in libzpool.so\n", varname);
-			return (EINVAL);
+			ret = EINVAL;
+			goto out_dlclose;
 		}
 		*var = (uint32_t)val;
 
-		dlclose(zpoolhdl);
 	} else {
 		fprintf(stderr, "Failed to open libzpool.so to set global "
 		    "variable\n");
-		return (EIO);
+		ret = EIO;
+		goto out_dlclose;
 	}
 
-	return (0);
+	ret = 0;
+
+out_dlclose:
+	dlclose(zpoolhdl);
+	free(varname);
+out_ret:
+	return (ret);
 }
 
 static nvlist_t *
diff --git a/sys/contrib/openzfs/lib/libzutil/os/linux/zutil_device_path_os.c b/sys/contrib/openzfs/lib/libzutil/os/linux/zutil_device_path_os.c
index 36331fd72bf7..1f767bb7a6e7 100644
--- a/sys/contrib/openzfs/lib/libzutil/os/linux/zutil_device_path_os.c
+++ b/sys/contrib/openzfs/lib/libzutil/os/linux/zutil_device_path_os.c
@@ -154,15 +154,124 @@ zfs_strip_path(char *path)
 	return (strrchr(path, '/') + 1);
 }
 
+/*
+ * Given a dev name like "sda", return the full enclosure sysfs path to
+ * the disk.  You can also pass in the name with "/dev" prepended
+ * to it (like /dev/sda).
+ *
+ * For example, disk "sda" in enclosure slot 1:
+ *     dev:            "sda"
+ *     returns:        "/sys/class/enclosure/1:0:3:0/Slot 1"
+ *
+ * 'dev' must be a non-devicemapper device.
+ *
+ * Returned string must be freed.
+ */
+char *
+zfs_get_enclosure_sysfs_path(const char *dev_name)
+{
+	DIR *dp = NULL;
+	struct dirent *ep;
+	char buf[MAXPATHLEN];
+	char *tmp1 = NULL;
+	char *tmp2 = NULL;
+	char *tmp3 = NULL;
+	char *path = NULL;
+	size_t size;
+	int tmpsize;
+
+	if (dev_name == NULL)
+		return (NULL);
+
+	/* If they preface 'dev' with a path (like "/dev") then strip it off */
+	tmp1 = strrchr(dev_name, '/');
+	if (tmp1 != NULL)
+		dev_name = tmp1 + 1;    /* +1 since we want the chr after '/' */
+
+	tmpsize = asprintf(&tmp1, "/sys/block/%s/device", dev_name);
+	if (tmpsize == -1 || tmp1 == NULL) {
+		tmp1 = NULL;
+		goto end;
+	}
+
+	dp = opendir(tmp1);
+	if (dp == NULL) {
+		tmp1 = NULL;	/* To make free() at the end a NOP */
+		goto end;
+	}
+
+	/*
+	 * Look though all sysfs entries in /sys/block/<dev>/device for
+	 * the enclosure symlink.
+	 */
+	while ((ep = readdir(dp))) {
+		/* Ignore everything that's not our enclosure_device link */
+		if (strstr(ep->d_name, "enclosure_device") == NULL)
+			continue;
+
+		if (asprintf(&tmp2, "%s/%s", tmp1, ep->d_name) == -1 ||
+		    tmp2 == NULL)
+			break;
+
+		size = readlink(tmp2, buf, sizeof (buf));
+
+		/* Did readlink fail or crop the link name? */
+		if (size == -1 || size >= sizeof (buf)) {
+			free(tmp2);
+			tmp2 = NULL;	/* To make free() at the end a NOP */
+			break;
+		}
+
+		/*
+		 * We got a valid link.  readlink() doesn't terminate strings
+		 * so we have to do it.
+		 */
+		buf[size] = '\0';
+
+		/*
+		 * Our link will look like:
+		 *
+		 * "../../../../port-11:1:2/..STUFF../enclosure/1:0:3:0/SLOT 1"
+		 *
+		 * We want to grab the "enclosure/1:0:3:0/SLOT 1" part
+		 */
+		tmp3 = strstr(buf, "enclosure");
+		if (tmp3 == NULL)
+			break;
+
+		if (asprintf(&path, "/sys/class/%s", tmp3) == -1) {
+			/* If asprintf() fails, 'path' is undefined */
+			path = NULL;
+			break;
+		}
+
+		if (path == NULL)
+			break;
+	}
+
+end:
+	free(tmp2);
+	free(tmp1);
+
+	if (dp != NULL)
+		closedir(dp);
+
+	return (path);
+}
+
 /*
  * Allocate and return the underlying device name for a device mapper device.
- * If a device mapper device maps to multiple devices, return the first device.
  *
  * For example, dm_name = "/dev/dm-0" could return "/dev/sda". Symlinks to a
  * DM device (like /dev/disk/by-vdev/A0) are also allowed.
  *
- * Returns device name, or NULL on error or no match.  If dm_name is not a DM
- * device then return NULL.
+ * If the DM device has multiple underlying devices (like with multipath
+ * DM devices), then favor underlying devices that have a symlink back to their
+ * back to their enclosure device in sysfs.  This will be useful for the
+ * zedlet scripts that toggle the fault LED.
+ *
+ * Returns an underlying device name, or NULL on error or no match.  If dm_name
+ * is not a DM device then return NULL.
  *
  * NOTE: The returned name string must be *freed*.
  */
@@ -176,6 +285,8 @@ dm_get_underlying_path(const char *dm_name)
 	char *path = NULL;
 	char *dev_str;
 	int size;
+	char *first_path = NULL;
+	char *enclosure_path;
 
 	if (dm_name == NULL)
 		return (NULL);
@@ -204,13 +315,27 @@ dm_get_underlying_path(const char *dm_name)
 		goto end;
 
 	/*
-	 * Return first entry (that isn't itself a directory) in the
-	 * directory containing device-mapper dependent (underlying)
-	 * devices.
+	 * A device-mapper device can have multiple paths to it (multipath).
+	 * Favor paths that have a symlink back to their enclosure device.
+	 * We have to do this since some enclosures may only provide a symlink
+	 * back for one underlying path to a disk and not the other.
+	 *
+	 * If no paths have links back to their enclosure, then just return the
+	 * first path.
 	 */
 	while ((ep = readdir(dp))) {
 		if (ep->d_type != DT_DIR) {	/* skip "." and ".." dirs */
+			if (!first_path)
+				first_path = strdup(ep->d_name);
+
+			enclosure_path =
+			    zfs_get_enclosure_sysfs_path(ep->d_name);
+
+			if (!enclosure_path)
+				continue;
+
 			size = asprintf(&path, "/dev/%s", ep->d_name);
+			free(enclosure_path);
 			break;
 		}
 	}
@@ -220,6 +345,17 @@ dm_get_underlying_path(const char *dm_name)
 		closedir(dp);
 	free(tmp);
 	free(realp);
+
+	if (!path) {
+		/*
+		 * None of the underlying paths had a link back to their
+		 * enclosure devices.  Throw up out hands and return the first
+		 * underlying path.
+		 */
+		size = asprintf(&path, "/dev/%s", first_path);
+	}
+
+	free(first_path);
 	return (path);
 }
 
@@ -331,110 +467,6 @@ zfs_get_underlying_path(const char *dev_name)
 	return (name);
 }
 
-/*
- * Given a dev name like "sda", return the full enclosure sysfs path to
- * the disk.  You can also pass in the name with "/dev" prepended
- * to it (like /dev/sda).
- *
- * For example, disk "sda" in enclosure slot 1:
- *     dev:            "sda"
- *     returns:        "/sys/class/enclosure/1:0:3:0/Slot 1"
- *
- * 'dev' must be a non-devicemapper device.
- *
- * Returned string must be freed.
- */
-char *
-zfs_get_enclosure_sysfs_path(const char *dev_name)
-{
-	DIR *dp = NULL;
-	struct dirent *ep;
-	char buf[MAXPATHLEN];
-	char *tmp1 = NULL;
-	char *tmp2 = NULL;
-	char *tmp3 = NULL;
-	char *path = NULL;
-	size_t size;
-	int tmpsize;
-
-	if (dev_name == NULL)
-		return (NULL);
-
-	/* If they preface 'dev' with a path (like "/dev") then strip it off */
-	tmp1 = strrchr(dev_name, '/');
-	if (tmp1 != NULL)
-		dev_name = tmp1 + 1;    /* +1 since we want the chr after '/' */
-
-	tmpsize = asprintf(&tmp1, "/sys/block/%s/device", dev_name);
-	if (tmpsize == -1 || tmp1 == NULL) {
-		tmp1 = NULL;
-		goto end;
-	}
-
-	dp = opendir(tmp1);
-	if (dp == NULL) {
-		tmp1 = NULL;	/* To make free() at the end a NOP */
-		goto end;
-	}
-
-	/*
-	 * Look though all sysfs entries in /sys/block/<dev>/device for
-	 * the enclosure symlink.
-	 */
-	while ((ep = readdir(dp))) {
-		/* Ignore everything that's not our enclosure_device link */
-		if (strstr(ep->d_name, "enclosure_device") == NULL)
-			continue;
-
-		if (asprintf(&tmp2, "%s/%s", tmp1, ep->d_name) == -1 ||
-		    tmp2 == NULL)
-			break;
-
-		size = readlink(tmp2, buf, sizeof (buf));
-
-		/* Did readlink fail or crop the link name? */
-		if (size == -1 || size >= sizeof (buf)) {
-			free(tmp2);
-			tmp2 = NULL;	/* To make free() at the end a NOP */
-			break;
-		}
-
-		/*
-		 * We got a valid link.  readlink() doesn't terminate strings
-		 * so we have to do it.
-		 */
-		buf[size] = '\0';
-
-		/*
-		 * Our link will look like:
-		 *
-		 * "../../../../port-11:1:2/..STUFF../enclosure/1:0:3:0/SLOT 1"
-		 *
-		 * We want to grab the "enclosure/1:0:3:0/SLOT 1" part
-		 */
-		tmp3 = strstr(buf, "enclosure");
-		if (tmp3 == NULL)
-			break;
-
-		if (asprintf(&path, "/sys/class/%s", tmp3) == -1) {
-			/* If asprintf() fails, 'path' is undefined */
-			path = NULL;
-			break;
-		}
-
-		if (path == NULL)
-			break;
-	}
-
-end:
-	free(tmp2);
-	free(tmp1);
-
-	if (dp != NULL)
-		closedir(dp);
-
-	return (path);
-}
 
 #ifdef HAVE_LIBUDEV
 
diff --git a/sys/contrib/openzfs/module/Makefile.bsd b/sys/contrib/openzfs/module/Makefile.bsd
index e7cddcc5bb5e..8aa4ed22275e 100644
--- a/sys/contrib/openzfs/module/Makefile.bsd
+++ b/sys/contrib/openzfs/module/Makefile.bsd
@@ -153,6 +153,7 @@ SRCS+=	abd_os.c \
 	zfs_dir.c \
 	zfs_ioctl_compat.c \
 	zfs_ioctl_os.c \
+	zfs_racct.c \
 	zfs_vfsops.c \
 	zfs_vnops_os.c \
 	zfs_znode.c \
diff --git a/sys/contrib/openzfs/module/os/freebsd/spl/spl_uio.c b/sys/contrib/openzfs/module/os/freebsd/spl/spl_uio.c
index f5f3524f7b9d..59a781ee1b64 100644
--- a/sys/contrib/openzfs/module/os/freebsd/spl/spl_uio.c
+++ b/sys/contrib/openzfs/module/os/freebsd/spl/spl_uio.c
@@ -41,10 +41,17 @@
  */
 
 #include <sys/param.h>
-#include <sys/uio.h>
+#include <sys/uio_impl.h>
 #include <sys/vnode.h>
 #include <sys/zfs_znode.h>
 
+int
+zfs_uiomove(void *cp, size_t n, zfs_uio_rw_t dir, zfs_uio_t *uio)
+{
+	ASSERT(zfs_uio_rw(uio) == dir);
+	return (uiomove(cp, (int)n, GET_UIO_STRUCT(uio)));
+}
+
 /*
  * same as zfs_uiomove() but doesn't modify uio structure.
  * return in cbytes how many bytes were copied.
diff --git a/sys/contrib/openzfs/module/os/freebsd/zfs/crypto_os.c b/sys/contrib/openzfs/module/os/freebsd/zfs/crypto_os.c
index fbf998416234..03d14ed7cf5c 100644
--- a/sys/contrib/openzfs/module/os/freebsd/zfs/crypto_os.c
+++ b/sys/contrib/openzfs/module/os/freebsd/zfs/crypto_os.c
@@ -293,8 +293,19 @@ freebsd_crypt_newsession(freebsd_crypt_session_t *sessp,
 		error = ENOTSUP;
 		goto bad;
 	}
-	error = crypto_newsession(&sessp->fs_sid, &csp,
-	    CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE);
+
+	/*
+	 * Disable the use of hardware drivers on FreeBSD 13 and later since
+	 * common crypto offload drivers impose constraints on AES-GCM AAD
+	 * lengths that make them unusable for ZFS, and we currently do not have
+	 * a mechanism to fall back to a software driver for requests not
+	 * handled by a hardware driver.
+	 *
+	 * On 12 we continue to permit the use of hardware drivers since
+	 * CPU-accelerated drivers such as aesni(4) register themselves as
+	 * hardware drivers.
+	 */
+	error = crypto_newsession(&sessp->fs_sid, &csp, CRYPTOCAP_F_SOFTWARE);
 	mtx_init(&sessp->fs_lock, "FreeBSD Cryptographic Session Lock",
 	    NULL, MTX_DEF);
 	crypt_sessions++;
diff --git a/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_racct.c b/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_racct.c
new file mode 100644
index 000000000000..b46cc046268e
--- /dev/null
+++ b/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_racct.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2021 iXsystems, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/zfs_racct.h>
+#include <sys/racct.h>
+
+void
+zfs_racct_read(uint64_t size, uint64_t iops)
+{
+	curthread->td_ru.ru_inblock += iops;
+#ifdef RACCT
+	if (racct_enable) {
+		PROC_LOCK(curproc);
+		racct_add_force(curproc, RACCT_READBPS, size);
+		racct_add_force(curproc, RACCT_READIOPS, iops);
+		PROC_UNLOCK(curproc);
+	}
+#endif /* RACCT */
+}
+
+void
+zfs_racct_write(uint64_t size, uint64_t iops)
+{
+	curthread->td_ru.ru_oublock += iops;
+#ifdef RACCT
+	if (racct_enable) {
+		PROC_LOCK(curproc);
+		racct_add_force(curproc, RACCT_WRITEBPS, size);
+		racct_add_force(curproc, RACCT_WRITEIOPS, iops);
+		PROC_UNLOCK(curproc);
+	}
+#endif /* RACCT */
+}
diff --git a/sys/contrib/openzfs/module/os/linux/zfs/Makefile.in b/sys/contrib/openzfs/module/os/linux/zfs/Makefile.in
index 75bec52c94e2..fa990776db83 100644
--- a/sys/contrib/openzfs/module/os/linux/zfs/Makefile.in
+++ b/sys/contrib/openzfs/module/os/linux/zfs/Makefile.in
@@ -22,6 +22,7 @@ $(MODULE)-objs += ../os/linux/zfs/zfs_debug.o
 $(MODULE)-objs += ../os/linux/zfs/zfs_dir.o
 $(MODULE)-objs += ../os/linux/zfs/zfs_file_os.o
 $(MODULE)-objs += ../os/linux/zfs/zfs_ioctl_os.o
+$(MODULE)-objs += ../os/linux/zfs/zfs_racct.o
 $(MODULE)-objs += ../os/linux/zfs/zfs_sysfs.o
 $(MODULE)-objs += ../os/linux/zfs/zfs_uio.o
 $(MODULE)-objs += ../os/linux/zfs/zfs_vfsops.o
diff --git a/sys/contrib/openzfs/module/os/linux/zfs/zfs_racct.c b/sys/contrib/openzfs/module/os/linux/zfs/zfs_racct.c
new file mode 100644
index 000000000000..7897e0f9edc1
--- /dev/null
+++ b/sys/contrib/openzfs/module/os/linux/zfs/zfs_racct.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2021 iXsystems, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/zfs_racct.h>
+
+void
+zfs_racct_read(uint64_t size, uint64_t iops)
+{
+}
+
+void
+zfs_racct_write(uint64_t size, uint64_t iops)
+{
+}
diff --git a/sys/contrib/openzfs/module/zfs/arc.c b/sys/contrib/openzfs/module/zfs/arc.c
index b4f0c8a85b64..9be0a4e8a4a9 100644
--- a/sys/contrib/openzfs/module/zfs/arc.c
+++ b/sys/contrib/openzfs/module/zfs/arc.c
@@ -308,6 +308,7 @@
 #include <sys/aggsum.h>
 #include <cityhash.h>
 #include <sys/vdev_trim.h>
+#include <sys/zfs_racct.h>
 #include <sys/zstd/zstd.h>
 
 #ifndef _KERNEL
@@ -6302,6 +6303,7 @@ arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
 			ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr),
 			    demand, prefetch, !HDR_ISTYPE_METADATA(hdr), data,
 			    metadata, misses);
+			zfs_racct_read(size, 1);
 		}
 
 		/* Check if the spa even has l2 configured */
diff --git a/sys/contrib/openzfs/module/zfs/dmu.c b/sys/contrib/openzfs/module/zfs/dmu.c
index ed345f0b6ec3..b46bf60d1a29 100644
--- a/sys/contrib/openzfs/module/zfs/dmu.c
+++ b/sys/contrib/openzfs/module/zfs/dmu.c
@@ -52,6 +52,7 @@
 #include <sys/zfeature.h>
 #include <sys/abd.h>
 #include <sys/trace_zfs.h>
+#include <sys/zfs_racct.h>
 #include <sys/zfs_rlock.h>
 #ifdef _KERNEL
 #include <sys/vmsystm.h>
@@ -551,6 +552,9 @@ dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset, uint64_t length,
 		dbp[i] = &db->db;
 	}
 
+	if (!read)
+		zfs_racct_write(length, nblks);
+
 	if ((flags & DMU_READ_NO_PREFETCH) == 0 &&
 	    DNODE_META_IS_CACHEABLE(dn) && length <= zfetch_array_rd_sz) {
 		dmu_zfetch(&dn->dn_zfetch, blkid, nblks,
@@ -1440,6 +1444,7 @@ dmu_assign_arcbuf_by_dnode(dnode_t *dn, uint64_t offset, arc_buf_t *buf,
 	 * same size as the dbuf.
 	 */
 	if (offset == db->db.db_offset && blksz == db->db.db_size) {
+		zfs_racct_write(blksz, 1);
 		dbuf_assign_arcbuf(db, buf, tx);
 		dbuf_rele(db, FTAG);
 	} else {
diff --git a/sys/contrib/openzfs/module/zfs/dsl_scan.c b/sys/contrib/openzfs/module/zfs/dsl_scan.c
index 40adfbcee4e1..a54cd6ca800e 100644
--- a/sys/contrib/openzfs/module/zfs/dsl_scan.c
+++ b/sys/contrib/openzfs/module/zfs/dsl_scan.c
@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011, 2018 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2021 by Delphix. All rights reserved.
  * Copyright 2016 Gary Mills
  * Copyright (c) 2017, 2019, Datto Inc. All rights reserved.
  * Copyright (c) 2015, Nexenta Systems, Inc. All rights reserved.
@@ -987,6 +987,10 @@ dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
 			    (u_longlong_t)spa_get_errlog_size(spa));
 			spa_async_request(spa, SPA_ASYNC_RESILVER);
 		}
+
+		/* Clear recent error events (i.e. duplicate events tracking) */
+		if (complete)
+			zfs_ereport_clear(spa, NULL);
 	}
 
 	scn->scn_phys.scn_end_time = gethrestime_sec();
diff --git a/sys/contrib/openzfs/module/zfs/spa_config.c b/sys/contrib/openzfs/module/zfs/spa_config.c
index 4a3144313267..ad82932ce567 100644
--- a/sys/contrib/openzfs/module/zfs/spa_config.c
+++ b/sys/contrib/openzfs/module/zfs/spa_config.c
@@ -32,7 +32,6 @@
 #include <sys/fm/fs/zfs.h>
 #include <sys/spa_impl.h>
 #include <sys/nvpair.h>
-#include <sys/uio.h>
 #include <sys/fs/zfs.h>
 #include <sys/vdev_impl.h>
 #include <sys/zfs_ioctl.h>
@@ -40,6 +39,7 @@
 #include <sys/sunddi.h>
 #include <sys/zfeature.h>
 #include <sys/zfs_file.h>
+#include <sys/zfs_context.h>
 #ifdef _KERNEL
 #include <sys/zone.h>
 #endif
diff --git a/sys/contrib/openzfs/module/zfs/vdev.c b/sys/contrib/openzfs/module/zfs/vdev.c
index 36001e0a6626..ad4f3efb87b1 100644
--- a/sys/contrib/openzfs/module/zfs/vdev.c
+++ b/sys/contrib/openzfs/module/zfs/vdev.c
@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011, 2020 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2021 by Delphix. All rights reserved.
  * Copyright 2017 Nexenta Systems, Inc.
  * Copyright (c) 2014 Integros [integros.com]
  * Copyright 2016 Toomas Soome <tsoome@me.com>
@@ -2527,7 +2527,7 @@ vdev_hold(vdev_t *vd)
 	for (int c = 0; c < vd->vdev_children; c++)
 		vdev_hold(vd->vdev_child[c]);
 
-	if (vd->vdev_ops->vdev_op_leaf)
+	if (vd->vdev_ops->vdev_op_leaf && vd->vdev_ops->vdev_op_hold != NULL)
 		vd->vdev_ops->vdev_op_hold(vd);
 }
 
@@ -2538,7 +2538,7 @@ vdev_rele(vdev_t *vd)
 	for (int c = 0; c < vd->vdev_children; c++)
 		vdev_rele(vd->vdev_child[c]);
 
-	if (vd->vdev_ops->vdev_op_leaf)
+	if (vd->vdev_ops->vdev_op_leaf && vd->vdev_ops->vdev_op_rele != NULL)
 		vd->vdev_ops->vdev_op_rele(vd);
 }
 
@@ -4170,6 +4170,9 @@ vdev_clear(spa_t *spa, vdev_t *vd)
 	    vd->vdev_parent->vdev_ops == &vdev_spare_ops &&
 	    vd->vdev_parent->vdev_child[0] == vd)
 		vd->vdev_unspare = B_TRUE;
+
+	/* Clear recent error events cache (i.e. duplicate events tracking) */
+	zfs_ereport_clear(spa, vd);
 }
 
 boolean_t
diff --git a/sys/contrib/openzfs/module/zfs/vdev_indirect.c b/sys/contrib/openzfs/module/zfs/vdev_indirect.c
index b26d0993711a..416f4c54d8e8 100644
--- a/sys/contrib/openzfs/module/zfs/vdev_indirect.c
+++ b/sys/contrib/openzfs/module/zfs/vdev_indirect.c
@@ -1485,14 +1485,12 @@ vdev_indirect_all_checksum_errors(zio_t *zio)
 
 			vdev_t *vd = ic->ic_vdev;
 
-			int ret = zfs_ereport_post_checksum(zio->io_spa, vd,
+			(void) zfs_ereport_post_checksum(zio->io_spa, vd,
 			    NULL, zio, is->is_target_offset, is->is_size,
 			    NULL, NULL, NULL);
-			if (ret != EALREADY) {
-				mutex_enter(&vd->vdev_stat_lock);
-				vd->vdev_stat.vs_checksum_errors++;
-				mutex_exit(&vd->vdev_stat_lock);
-			}
+			mutex_enter(&vd->vdev_stat_lock);
+			vd->vdev_stat.vs_checksum_errors++;
+			mutex_exit(&vd->vdev_stat_lock);
 		}
 	}
 }
diff --git a/sys/contrib/openzfs/module/zfs/vdev_raidz.c b/sys/contrib/openzfs/module/zfs/vdev_raidz.c
index f4812e61252c..57a594c80ce3 100644
--- a/sys/contrib/openzfs/module/zfs/vdev_raidz.c
+++ b/sys/contrib/openzfs/module/zfs/vdev_raidz.c
@@ -1852,14 +1852,12 @@ raidz_checksum_error(zio_t *zio, raidz_col_t *rc, abd_t *bad_data)
 		zbc.zbc_has_cksum = 0;
 		zbc.zbc_injected = rm->rm_ecksuminjected;
 
-		int ret = zfs_ereport_post_checksum(zio->io_spa, vd,
+		(void) zfs_ereport_post_checksum(zio->io_spa, vd,
 		    &zio->io_bookmark, zio, rc->rc_offset, rc->rc_size,
 		    rc->rc_abd, bad_data, &zbc);
-		if (ret != EALREADY) {
-			mutex_enter(&vd->vdev_stat_lock);
-			vd->vdev_stat.vs_checksum_errors++;
-			mutex_exit(&vd->vdev_stat_lock);
-		}
+		mutex_enter(&vd->vdev_stat_lock);
+		vd->vdev_stat.vs_checksum_errors++;
+		mutex_exit(&vd->vdev_stat_lock);
 	}
 }
 
@@ -2453,14 +2451,12 @@ vdev_raidz_io_done_unrecoverable(zio_t *zio)
 			zbc.zbc_has_cksum = 0;
 			zbc.zbc_injected = rm->rm_ecksuminjected;
 
-			int ret = zfs_ereport_start_checksum(zio->io_spa,
+			(void) zfs_ereport_start_checksum(zio->io_spa,
 			    cvd, &zio->io_bookmark, zio, rc->rc_offset,
 			    rc->rc_size, (void *)(uintptr_t)c, &zbc);
-			if (ret != EALREADY) {
-				mutex_enter(&cvd->vdev_stat_lock);
-				cvd->vdev_stat.vs_checksum_errors++;
-				mutex_exit(&cvd->vdev_stat_lock);
-			}
+			mutex_enter(&cvd->vdev_stat_lock);
+			cvd->vdev_stat.vs_checksum_errors++;
+			mutex_exit(&cvd->vdev_stat_lock);
 		}
 	}
 }
diff --git a/sys/contrib/openzfs/module/zfs/vdev_rebuild.c b/sys/contrib/openzfs/module/zfs/vdev_rebuild.c
index 784d1af15a81..037abc01f7a7 100644
--- a/sys/contrib/openzfs/module/zfs/vdev_rebuild.c
+++ b/sys/contrib/openzfs/module/zfs/vdev_rebuild.c
@@ -338,6 +338,9 @@ vdev_rebuild_complete_sync(void *arg, dmu_tx_t *tx)
 	}
 
 	cv_broadcast(&vd->vdev_rebuild_cv);
+
+	/* Clear recent error events (i.e. duplicate events tracking) */
+	zfs_ereport_clear(spa, NULL);
 }
 
 /*
diff --git a/sys/contrib/openzfs/module/zfs/zfs_fm.c b/sys/contrib/openzfs/module/zfs/zfs_fm.c
index ea71ef325c89..9e9f4a80ba1d 100644
--- a/sys/contrib/openzfs/module/zfs/zfs_fm.c
+++ b/sys/contrib/openzfs/module/zfs/zfs_fm.c
@@ -24,7 +24,7 @@
  */
 
 /*
- * Copyright (c) 2012,2020 by Delphix. All rights reserved.
+ * Copyright (c) 2012,2021 by Delphix. All rights reserved.
  */
 
 #include <sys/spa.h>
@@ -247,6 +247,44 @@ zfs_ereport_schedule_cleaner(void)
 	    ddi_get_lbolt() + NSEC_TO_TICK(timeout));
 }
 
+/*
+ * Clear entries for a given vdev or all vdevs in a pool when vdev == NULL
+ */
+void
+zfs_ereport_clear(spa_t *spa, vdev_t *vd)
+{
+	uint64_t vdev_guid, pool_guid;
+	int cnt = 0;
+
+	ASSERT(vd != NULL || spa != NULL);
+	if (vd == NULL) {
+		vdev_guid = 0;
+		pool_guid = spa_guid(spa);
+	} else {
+		vdev_guid = vd->vdev_guid;
+		pool_guid = 0;
+	}
+
+	mutex_enter(&recent_events_lock);
+
+	recent_events_node_t *next = list_head(&recent_events_list);
+	while (next != NULL) {
+		recent_events_node_t *entry = next;
+
+		next = list_next(&recent_events_list, next);
+
+		if (entry->re_vdev_guid == vdev_guid ||
+		    entry->re_pool_guid == pool_guid) {
+			avl_remove(&recent_events_tree, entry);
+			list_remove(&recent_events_list, entry);
+			kmem_free(entry, sizeof (*entry));
+			cnt++;
+		}
+	}
+
+	mutex_exit(&recent_events_lock);
+}
+
 /*
  * Check if an ereport would be a duplicate of one recently posted.
  *
@@ -951,6 +989,12 @@ annotate_ecksum(nvlist_t *ereport, zio_bad_cksum_t *info,
 	}
 	return (eip);
 }
+#else
+/*ARGSUSED*/
+void
+zfs_ereport_clear(spa_t *spa, vdev_t *vd)
+{
+}
 #endif
 
 /*
diff --git a/sys/contrib/openzfs/module/zfs/zfs_ioctl.c b/sys/contrib/openzfs/module/zfs/zfs_ioctl.c
index 0e35fd069cbb..922253469fba 100644
--- a/sys/contrib/openzfs/module/zfs/zfs_ioctl.c
+++ b/sys/contrib/openzfs/module/zfs/zfs_ioctl.c
@@ -159,7 +159,7 @@
 #include <sys/types.h>
 #include <sys/param.h>
 #include <sys/errno.h>
-#include <sys/uio.h>
+#include <sys/uio_impl.h>
 #include <sys/file.h>
 #include <sys/kmem.h>
 #include <sys/cmn_err.h>
diff --git a/sys/contrib/openzfs/module/zfs/zfs_vnops.c b/sys/contrib/openzfs/module/zfs/zfs_vnops.c
index 61d5f06c6455..a35c17f86f93 100644
--- a/sys/contrib/openzfs/module/zfs/zfs_vnops.c
+++ b/sys/contrib/openzfs/module/zfs/zfs_vnops.c
@@ -34,7 +34,7 @@
 #include <sys/time.h>
 #include <sys/sysmacros.h>
 #include <sys/vfs.h>
-#include <sys/uio.h>
+#include <sys/uio_impl.h>
 #include <sys/file.h>
 #include <sys/stat.h>
 #include <sys/kmem.h>
diff --git a/sys/contrib/openzfs/module/zfs/zio.c b/sys/contrib/openzfs/module/zfs/zio.c
index 7f3cb19d46db..262ca24b1443 100644
--- a/sys/contrib/openzfs/module/zfs/zio.c
+++ b/sys/contrib/openzfs/module/zfs/zio.c
@@ -4286,15 +4286,12 @@ zio_checksum_verify(zio_t *zio)
 		zio->io_error = error;
 		if (error == ECKSUM &&
 		    !(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
-			int ret = zfs_ereport_start_checksum(zio->io_spa,
+			(void) zfs_ereport_start_checksum(zio->io_spa,
 			    zio->io_vd, &zio->io_bookmark, zio,
 			    zio->io_offset, zio->io_size, NULL, &info);
-
-			if (ret != EALREADY) {
-				mutex_enter(&zio->io_vd->vdev_stat_lock);
-				zio->io_vd->vdev_stat.vs_checksum_errors++;
-				mutex_exit(&zio->io_vd->vdev_stat_lock);
-			}
+			mutex_enter(&zio->io_vd->vdev_stat_lock);
+			zio->io_vd->vdev_stat.vs_checksum_errors++;
+			mutex_exit(&zio->io_vd->vdev_stat_lock);
 		}
 	}
 
diff --git a/sys/contrib/openzfs/scripts/zfs.sh b/sys/contrib/openzfs/scripts/zfs.sh
index c131429c919c..2f5f3f8fdb54 100755
--- a/sys/contrib/openzfs/scripts/zfs.sh
+++ b/sys/contrib/openzfs/scripts/zfs.sh
@@ -198,7 +198,7 @@ unload_modules_linux() {
 
 		if [ "$USE_COUNT" = "0" ] ; then
 			unload_module_linux "$KMOD" || return 1
-		else
+		elif [ "$USE_COUNT" != "" ] ; then
 			echo "Module ${NAME} is still in use!"
 			return 1
 		fi
diff --git a/sys/contrib/openzfs/tests/runfiles/common.run b/sys/contrib/openzfs/tests/runfiles/common.run
index 9468ee06de44..e656785d95d8 100644
--- a/sys/contrib/openzfs/tests/runfiles/common.run
+++ b/sys/contrib/openzfs/tests/runfiles/common.run
@@ -362,7 +362,8 @@ tags = ['functional', 'cli_root', 'zpool_detach']
 
 [tests/functional/cli_root/zpool_events]
 tests = ['zpool_events_clear', 'zpool_events_cliargs', 'zpool_events_follow',
-    'zpool_events_poolname', 'zpool_events_errors', 'zpool_events_duplicates']
+    'zpool_events_poolname', 'zpool_events_errors', 'zpool_events_duplicates',
+    'zpool_events_clear_retained']
 tags = ['functional', 'cli_root', 'zpool_events']
 
 [tests/functional/cli_root/zpool_export]
diff --git a/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/Makefile.am b/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/Makefile.am
index 99c46f0143c2..765df102229d 100644
--- a/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/Makefile.am
+++ b/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/Makefile.am
@@ -11,7 +11,8 @@ dist_pkgdata_SCRIPTS = \
 	zpool_events_follow.ksh \
 	zpool_events_poolname.ksh \
 	zpool_events_errors.ksh \
-	zpool_events_duplicates.ksh
+	zpool_events_duplicates.ksh \
+	zpool_events_clear_retained.ksh
 
 dist_pkgdata_DATA = \
 	zpool_events.cfg \
diff --git a/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/zpool_events_clear_retained.ksh b/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/zpool_events_clear_retained.ksh
new file mode 100755
index 000000000000..fdf56b2cf9a6
--- /dev/null
+++ b/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/zpool_events_clear_retained.ksh
@@ -0,0 +1,135 @@
+#!/bin/ksh -p
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2018 by Lawrence Livermore National Security, LLC.
+# Copyright (c) 2021 by Delphix. All rights reserved.
+#
+
+# DESCRIPTION:
+#	Verify that new errors after a pool scrub are considered a duplicate
+#
+# STRATEGY:
+#	1. Create a raidz pool with a file
+#	2. Inject garbage into one of the vdevs
+#	3. Scrub the pool
+#	4. Observe the checksum error counts
+#	5. Repeat inject and pool scrub
+#	6. Verify that second pass also produces similar errors (i.e. not
+#	   treated as a duplicate)
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+verify_runnable "both"
+
+MOUNTDIR=$TEST_BASE_DIR/mount
+FILEPATH=$MOUNTDIR/target
+VDEV1=$TEST_BASE_DIR/vfile1
+VDEV2=$TEST_BASE_DIR/vfile2
+VDEV3=$TEST_BASE_DIR/vfile3
+SUPPLY=$TEST_BASE_DIR/supply
+POOL=test_pool
+FILESIZE="15M"
+DAMAGEBLKS=10
+
+OLD_LEN_MAX=$(get_tunable ZEVENT_LEN_MAX)
+RETAIN_MAX=$(get_tunable ZEVENT_RETAIN_MAX)
+OLD_CHECKSUMS=$(get_tunable CHECKSUM_EVENTS_PER_SECOND)
+
+EREPORTS="$STF_SUITE/tests/functional/cli_root/zpool_events/ereports"
+
+function cleanup
+{
+	log_must set_tunable64 CHECKSUM_EVENTS_PER_SECOND $OLD_CHECKSUMS
+	log_must set_tunable64 ZEVENT_LEN_MAX $OLD_LEN_MAX
+
+	zpool events -c
+	if poolexists $POOL ; then
+		zpool export $POOL
+	fi
+	log_must rm -f $VDEV1 $VDEV2 $VDEV3
+}
+
+function damage_and_repair
+{
+	log_must zpool clear $POOL $VDEV1
+	log_must zpool events -c
+
+	log_note injecting damage to $VDEV1
+	log_must dd conv=notrunc if=$SUPPLY of=$VDEV1 bs=1M seek=4 count=$DAMAGEBLKS
+	log_must zpool scrub $POOL
+	log_must zpool wait -t scrub $POOL
+	log_note "pass $1 observed $($EREPORTS | grep -c checksum) checksum ereports"
+
+	repaired=$(zpool status $POOL | grep "scan: scrub repaired" | awk '{print $4}')
+	if [ "$repaired" == "0B" ]; then
+		log_fail "INVALID TEST -- expected scrub to repair some blocks"
+	else
+		log_note "$repaired repaired during scrub"
+	fi
+}
+
+function checksum_error_count
+{
+	zpool status -p $POOL | grep $VDEV1 | awk '{print $5}'
+}
+
+assertion="Damage to recently repaired blocks should be reported/counted"
+log_assert "$assertion"
+log_note "zevent retain max setting: $RETAIN_MAX"
+
+log_onexit cleanup
+
+# Set our threshold high to avoid dropping events.
+set_tunable64 ZEVENT_LEN_MAX 20000
+set_tunable64 CHECKSUM_EVENTS_PER_SECOND 20000
+
+# Initialize resources for the test
+log_must truncate -s $MINVDEVSIZE $VDEV1 $VDEV2 $VDEV3
+log_must dd if=/dev/urandom of=$SUPPLY bs=1M count=$DAMAGEBLKS
+log_must mkdir -p $MOUNTDIR
+log_must zpool create -f -m $MOUNTDIR -o failmode=continue $POOL raidz $VDEV1 $VDEV2 $VDEV3
+log_must zfs set compression=off recordsize=16k $POOL
+# create a file full of zeros
+log_must mkfile -v $FILESIZE $FILEPATH
+log_must zpool sync $POOL
+
+# run once and observe the checksum errors
+damage_and_repair 1
+errcnt=$(checksum_error_count)
+log_note "$errcnt errors observed"
+# set expectaton of at least 75% of what we observed in first pass
+(( expected = (errcnt * 75) / 100 ))
+
+# run again and we should observe new checksum errors
+damage_and_repair 2
+errcnt=$(checksum_error_count)
+
+log_must zpool destroy $POOL
+
+if (( errcnt < expected )); then
+	log_fail "FAILED -- expecting at least $expected checksum errors but only observed $errcnt"
+else
+	log_note observed $errcnt new checksum errors after a scrub
+	log_pass "$assertion"
+fi
+
diff --git a/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/zpool_events_duplicates.ksh b/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/zpool_events_duplicates.ksh
index 1ba7b1b34496..d4194a5b8f5b 100755
--- a/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/zpool_events_duplicates.ksh
+++ b/sys/contrib/openzfs/tests/zfs-tests/tests/functional/cli_root/zpool_events/zpool_events_duplicates.ksh
@@ -114,21 +114,10 @@ function do_dup_test
 	if [ "$RW" == "write" ] ; then
 		log_must mkfile $FILESIZE $FILEPATH
 		log_must zpool sync $POOL
-	else
-		# scrub twice to generate some duplicates
-		log_must zpool scrub $POOL
-		log_must zpool wait -t scrub $POOL
-		log_must zpool scrub $POOL
-		log_must zpool wait -t scrub $POOL
 	fi
 
 	log_must zinject -c all
 
-	# Wait for the pool to settle down and finish resilvering (if
-	# necessary).  We want the errors to stop incrementing before we
-	# check for duplicates.
-	zpool wait -t resilver $POOL
-
 	ereports="$($EREPORTS | sort)"
 	actual=$(echo "$ereports" | wc -l)
 	unique=$(echo "$ereports" | uniq | wc -l)
diff --git a/sys/modules/zfs/Makefile b/sys/modules/zfs/Makefile
index 49256609b549..0fab9f552314 100644
--- a/sys/modules/zfs/Makefile
+++ b/sys/modules/zfs/Makefile
@@ -126,6 +126,7 @@ SRCS+=	abd_os.c \
 	zfs_ioctl_compat.c \
 	zfs_ioctl_os.c \
 	zfs_log.c \
+	zfs_racct.c \
 	zfs_replay.c \
 	zfs_vfsops.c \
 	zfs_vnops_os.c \
diff --git a/sys/modules/zfs/zfs_config.h b/sys/modules/zfs/zfs_config.h
index 18ca44d1b3c1..0ef2200d1940 100644
--- a/sys/modules/zfs/zfs_config.h
+++ b/sys/modules/zfs/zfs_config.h
@@ -764,7 +764,7 @@
 #define ZFS_META_NAME "zfs"
 
 /* Define the project release. */
-#define ZFS_META_RELEASE "FreeBSD_gbf156c966"
+#define ZFS_META_RELEASE "FreeBSD_g9312e0fd1"
 
 /* Define the project version. */
 #define ZFS_META_VERSION "2.0.0"