diff --git a/include/sys/zap_impl.h b/include/sys/zap_impl.h
index b4f30405eba..6c72cd977c8 100644
--- a/include/sys/zap_impl.h
+++ b/include/sys/zap_impl.h
@@ -280,8 +280,7 @@ uint64_t zap_getflags(zap_t *zap);
 
 /* Microzap implementation. */
 zap_t *mzap_open(dmu_buf_t *db);
-int mzap_upgrade(zap_t **zapp, const void *tag, dmu_tx_t *tx,
-    zap_flags_t flags);
+int mzap_upgrade(zap_t **zapp, dmu_tx_t *tx, zap_flags_t flags);
 mzap_ent_t *mze_find(zap_name_t *zn, zfs_btree_index_t *idx);
 boolean_t mze_canfit_fzap_leaf(zap_name_t *zn, uint64_t hash);
 void mze_destroy(zap_t *zap);
@@ -300,19 +299,17 @@ int fzap_lookup(zap_name_t *zn,
     uint64_t *actual_num_integers);
 void fzap_prefetch(zap_name_t *zn);
 int fzap_add(zap_name_t *zn, uint64_t integer_size, uint64_t num_integers,
-    const void *val, const void *tag, dmu_tx_t *tx);
-int fzap_update(zap_name_t *zn,
-    int integer_size, uint64_t num_integers, const void *val,
-    const void *tag, dmu_tx_t *tx);
+    const void *val, dmu_tx_t *tx);
+int fzap_update(zap_name_t *zn, int integer_size, uint64_t num_integers,
+    const void *val, dmu_tx_t *tx);
 int fzap_length(zap_name_t *zn,
     uint64_t *integer_size, uint64_t *num_integers);
 int fzap_remove(zap_name_t *zn, dmu_tx_t *tx);
 int fzap_cursor_retrieve(zap_t *zap, zap_cursor_t *zc, zap_attribute_t *za);
 void fzap_get_stats(zap_t *zap, zap_stats_t *zs);
 void zap_put_leaf(struct zap_leaf *l);
-int fzap_add_cd(zap_name_t *zn,
-    uint64_t integer_size, uint64_t num_integers,
-    const void *val, uint32_t cd, const void *tag, dmu_tx_t *tx);
+int fzap_add_cd(zap_name_t *zn, uint64_t integer_size, uint64_t num_integers,
+    const void *val, uint32_t cd, dmu_tx_t *tx);
 void fzap_upgrade(zap_t *zap, dmu_tx_t *tx, zap_flags_t flags);
 
 #ifdef	__cplusplus
diff --git a/module/zfs/zap.c b/module/zfs/zap.c
index 8e3cf7e1c47..f4575946939 100644
--- a/module/zfs/zap.c
+++ b/module/zfs/zap.c
@@ -500,14 +500,13 @@ zap_add_impl(zap_t *zap, const char *key,
 		return (SET_ERROR(ENOTSUP));
 	}
 	if (!zap->zap_ismicro) {
-		err = fzap_add(zn, integer_size, num_integers, val, tag, tx);
+		err = fzap_add(zn, integer_size, num_integers, val, tx);
 	} else if (integer_size != 8 || num_integers != 1 ||
 	    strlen(key) >= MZAP_NAME_LEN ||
 	    !mze_canfit_fzap_leaf(zn, zn->zn_hash)) {
-		err = mzap_upgrade(&zn->zn_zap, tag, tx, 0);
+		err = mzap_upgrade(&zn->zn_zap, tx, 0);
 		if (err == 0) {
-			err = fzap_add(zn, integer_size, num_integers, val,
-			    tag, tx);
+			err = fzap_add(zn, integer_size, num_integers, val, tx);
 		}
 	} else {
 		zfs_btree_index_t idx;
@@ -569,7 +568,7 @@ zap_add_uint64_impl(zap_t *zap, const uint64_t *key,
 		zap_unlock(zap, tag);
 		return (SET_ERROR(ENOTSUP));
 	}
-	err = fzap_add(zn, integer_size, num_integers, val, tag, tx);
+	err = fzap_add(zn, integer_size, num_integers, val, tx);
 	zap_name_free(zn);
 	zap_unlock(zap, tag);
 	return (err);
@@ -628,17 +627,16 @@ zap_update(objset_t *os, uint64_t zapobj, const char *name,
 		return (SET_ERROR(ENOTSUP));
 	}
 	if (!zap->zap_ismicro) {
-		err = fzap_update(zn, integer_size, num_integers, val,
-		    FTAG, tx);
+		err = fzap_update(zn, integer_size, num_integers, val, tx);
 	} else if (integer_size != 8 || num_integers != 1 ||
 	    strlen(name) >= MZAP_NAME_LEN) {
 		dprintf("upgrading obj %llu: intsz=%u numint=%llu name=%s\n",
 		    (u_longlong_t)zapobj, integer_size,
 		    (u_longlong_t)num_integers, name);
-		err = mzap_upgrade(&zn->zn_zap, FTAG, tx, 0);
+		err = mzap_upgrade(&zn->zn_zap, tx, 0);
 		if (err == 0) {
 			err = fzap_update(zn, integer_size, num_integers,
-			    val, FTAG, tx);
+			    val, tx);
 		}
 	} else {
 		zfs_btree_index_t idx;
@@ -669,7 +667,7 @@ zap_update_uint64_impl(zap_t *zap, const uint64_t *key, int key_numints,
 		zap_unlock(zap, tag);
 		return (SET_ERROR(ENOTSUP));
 	}
-	err = fzap_update(zn, integer_size, num_integers, val, tag, tx);
+	err = fzap_update(zn, integer_size, num_integers, val, tx);
 	zap_name_free(zn);
 	zap_unlock(zap, tag);
 	return (err);
diff --git a/module/zfs/zap_fat.c b/module/zfs/zap_fat.c
index 6cf773e786e..7b48c6fd5a1 100644
--- a/module/zfs/zap_fat.c
+++ b/module/zfs/zap_fat.c
@@ -697,10 +697,8 @@ zap_deref_leaf(zap_t *zap, uint64_t h, dmu_tx_t *tx, krw_t lt, zap_leaf_t **lp)
 }
 
 static int
-zap_expand_leaf(zap_name_t *zn, zap_leaf_t *l,
-    const void *tag, dmu_tx_t *tx, zap_leaf_t **lp)
+zap_expand_leaf(zap_name_t *zn, zap_leaf_t *l, dmu_tx_t *tx, zap_leaf_t **lp)
 {
-	(void) tag;
 	zap_t *zap = zn->zn_zap;
 	uint64_t hash = zn->zn_hash;
 	int err;
@@ -780,10 +778,8 @@ zap_expand_leaf(zap_name_t *zn, zap_leaf_t *l,
 }
 
 static void
-zap_put_leaf_maybe_grow_ptrtbl(zap_name_t *zn, zap_leaf_t *l,
-    const void *tag, dmu_tx_t *tx)
+zap_put_leaf_maybe_grow_ptrtbl(zap_name_t *zn, zap_leaf_t *l, dmu_tx_t *tx)
 {
-	(void) tag;
 	zap_t *zap = zn->zn_zap;
 	int shift = zap_f_phys(zap)->zap_ptrtbl.zt_shift;
 	int leaffull = (zap_leaf_phys(l)->l_hdr.lh_prefix_len == shift &&
@@ -887,9 +883,8 @@ fzap_lookup(zap_name_t *zn,
 }
 
 int
-fzap_add_cd(zap_name_t *zn,
-    uint64_t integer_size, uint64_t num_integers,
-    const void *val, uint32_t cd, const void *tag, dmu_tx_t *tx)
+fzap_add_cd(zap_name_t *zn, uint64_t integer_size, uint64_t num_integers,
+    const void *val, uint32_t cd, dmu_tx_t *tx)
 {
 	zap_leaf_t *l;
 	int err;
@@ -918,7 +913,7 @@ fzap_add_cd(zap_name_t *zn,
 	if (err == 0) {
 		zap_increment_num_entries(zap, 1, tx);
 	} else if (err == EAGAIN) {
-		err = zap_expand_leaf(zn, l, tag, tx, &l);
+		err = zap_expand_leaf(zn, l, tx, &l);
 		if (err == 0)
 			goto retry;
 	}
@@ -928,28 +923,26 @@ fzap_add_cd(zap_name_t *zn,
 		if (err == ENOSPC)
 			zap_put_leaf(l);
 		else
-			zap_put_leaf_maybe_grow_ptrtbl(zn, l, tag, tx);
+			zap_put_leaf_maybe_grow_ptrtbl(zn, l, tx);
 	}
 	return (err);
 }
 
 int
-fzap_add(zap_name_t *zn,
-    uint64_t integer_size, uint64_t num_integers,
-    const void *val, const void *tag, dmu_tx_t *tx)
+fzap_add(zap_name_t *zn, uint64_t integer_size, uint64_t num_integers,
+    const void *val, dmu_tx_t *tx)
 {
 	int err = fzap_check(zn, integer_size, num_integers);
 	if (err != 0)
 		return (err);
 
 	return (fzap_add_cd(zn, integer_size, num_integers,
-	    val, ZAP_NEED_CD, tag, tx));
+	    val, ZAP_NEED_CD, tx));
 }
 
 int
-fzap_update(zap_name_t *zn,
-    int integer_size, uint64_t num_integers, const void *val,
-    const void *tag, dmu_tx_t *tx)
+fzap_update(zap_name_t *zn, int integer_size, uint64_t num_integers,
+    const void *val, dmu_tx_t *tx)
 {
 	zap_leaf_t *l;
 	int err;
@@ -980,7 +973,7 @@ fzap_update(zap_name_t *zn,
 	}
 
 	if (err == EAGAIN) {
-		err = zap_expand_leaf(zn, l, tag, tx, &l);
+		err = zap_expand_leaf(zn, l, tx, &l);
 		if (err == 0)
 			goto retry;
 	}
@@ -989,7 +982,7 @@ fzap_update(zap_name_t *zn,
 		if (err == ENOSPC)
 			zap_put_leaf(l);
 		else
-			zap_put_leaf_maybe_grow_ptrtbl(zn, l, tag, tx);
+			zap_put_leaf_maybe_grow_ptrtbl(zn, l, tx);
 	}
 	return (err);
 }
diff --git a/module/zfs/zap_impl.c b/module/zfs/zap_impl.c
index b72aa82349e..0c2ba1cdbfe 100644
--- a/module/zfs/zap_impl.c
+++ b/module/zfs/zap_impl.c
@@ -285,12 +285,8 @@ zap_hash(zap_name_t *zn)
 	return (h);
 }
 
-/*
- * This routine "consumes" the caller's hold on the dbuf, which must
- * have the specified tag.
- */
 static int
-zap_lock_impl(dnode_t *dn, dmu_buf_t *db, const void *tag, dmu_tx_t *tx,
+zap_lock_impl(dnode_t *dn, dmu_buf_t *db, dmu_tx_t *tx,
     krw_t lti, boolean_t fatreader, boolean_t adding, zap_t **zapp)
 {
 	ASSERT0(db->db_offset);
@@ -349,7 +345,7 @@ zap_lock_impl(dnode_t *dn, dmu_buf_t *db, const void *tag, dmu_tx_t *tx,
 			dprintf("upgrading obj %llu: num_entries=%u\n",
 			    (u_longlong_t)obj, zap->zap_m.zap_num_entries);
 			*zapp = zap;
-			int err = mzap_upgrade(zapp, tag, tx, 0);
+			int err = mzap_upgrade(zapp, tx, 0);
 			if (err != 0)
 				rw_exit(&zap->zap_rwlock);
 			return (err);
@@ -399,7 +395,7 @@ zap_lock_by_dnode(dnode_t *dn, dmu_tx_t *tx,
 	err = dmu_buf_hold_by_dnode(dn, 0, tag, &db, DMU_READ_NO_PREFETCH);
 	if (err != 0)
 		return (err);
-	err = zap_lock_impl(dn, db, tag, tx, lti, fatreader, adding, zapp);
+	err = zap_lock_impl(dn, db, tx, lti, fatreader, adding, zapp);
 	if (err != 0)
 		dmu_buf_rele(db, tag);
 	else
diff --git a/module/zfs/zap_micro.c b/module/zfs/zap_micro.c
index 727f72d999f..a7c9c9c03b4 100644
--- a/module/zfs/zap_micro.c
+++ b/module/zfs/zap_micro.c
@@ -324,7 +324,7 @@ mzap_open(dmu_buf_t *db)
 }
 
 int
-mzap_upgrade(zap_t **zapp, const void *tag, dmu_tx_t *tx, zap_flags_t flags)
+mzap_upgrade(zap_t **zapp, dmu_tx_t *tx, zap_flags_t flags)
 {
 	int err = 0;
 	zap_t *zap = *zapp;
@@ -362,7 +362,7 @@ mzap_upgrade(zap_t **zapp, const void *tag, dmu_tx_t *tx, zap_flags_t flags)
 		zap_name_init_str(zn, mze->mze_name, 0);
 		/* If we fail here, we would end up losing entries */
 		VERIFY0(fzap_add_cd(zn, 8, 1, &mze->mze_value, mze->mze_cd,
-		    tag, tx));
+		    tx));
 	}
 	zap_name_free(zn);
 	vmem_free(mzp, sz);
@@ -406,7 +406,7 @@ mzap_create_impl(dnode_t *dn, int normflags, zap_flags_t flags, dmu_tx_t *tx)
 		/* Only fat zap supports flags; upgrade immediately. */
 		VERIFY0(zap_lock_by_dnode(dn, tx,
 		    RW_WRITER, B_FALSE, B_FALSE, FTAG, &zap));
-		VERIFY0(mzap_upgrade(&zap, FTAG, tx, flags));
+		VERIFY0(mzap_upgrade(&zap, tx, flags));
 		zap_unlock(zap, FTAG);
 	}