diff --git a/man/man4/zfs.4 b/man/man4/zfs.4
index efdd10409..6207f3ae9 100644
--- a/man/man4/zfs.4
+++ b/man/man4/zfs.4
@@ -15,7 +15,7 @@
 .\" own identifying information:
 .\" Portions Copyright [yyyy] [name of copyright owner]
 .\"
-.Dd December 21, 2022
+.Dd January 10, 2023
 .Dt ZFS 4
 .Os
 .
@@ -239,6 +239,12 @@ relative to the pool.
 Make some blocks above a certain size be gang blocks.
 This option is used by the test suite to facilitate testing.
 .
+.It Sy zfs_default_bs Ns = Ns Sy 9 Po 512 B Pc Pq int
+Default dnode block size as a power of 2.
+.
+.It Sy zfs_default_ibs Ns = Ns Sy 17 Po 128 KiB Pc Pq int
+Default dnode indirect block size as a power of 2.
+.
 .It Sy zfs_history_output_max Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq u64
 When attempting to log an output nvlist of an ioctl in the on-disk history,
 the output will not be stored if it is larger than this size (in bytes).
diff --git a/module/os/freebsd/zfs/sysctl_os.c b/module/os/freebsd/zfs/sysctl_os.c
index 05d58ad74..bd6cfc86c 100644
--- a/module/os/freebsd/zfs/sysctl_os.c
+++ b/module/os/freebsd/zfs/sysctl_os.c
@@ -472,20 +472,6 @@ SYSCTL_UINT(_vfs_zfs_zfetch, OID_AUTO, max_idistance,
 
 /* dnode.c */
 
-extern int zfs_default_bs;
-
-/* BEGIN CSTYLED */
-SYSCTL_INT(_vfs_zfs, OID_AUTO, default_bs, CTLFLAG_RWTUN,
-	&zfs_default_bs, 0, "Default dnode block shift");
-/* END CSTYLED */
-
-extern int zfs_default_ibs;
-
-/* BEGIN CSTYLED */
-SYSCTL_INT(_vfs_zfs, OID_AUTO, default_ibs, CTLFLAG_RWTUN,
-    &zfs_default_ibs, 0, "Default dnode indirect block shift");
-/* END CSTYLED */
-
 /* dsl_scan.c */
 
 /* metaslab.c */
diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c
index 2a2c66f9f..0fc49018c 100644
--- a/module/zfs/dnode.c
+++ b/module/zfs/dnode.c
@@ -2696,3 +2696,8 @@ EXPORT_SYMBOL(dnode_free_range);
 EXPORT_SYMBOL(dnode_evict_dbufs);
 EXPORT_SYMBOL(dnode_evict_bonus);
 #endif
+
+ZFS_MODULE_PARAM(zfs, zfs_, default_bs, INT, ZMOD_RW,
+	"Default dnode block shift");
+ZFS_MODULE_PARAM(zfs, zfs_, default_ibs, INT, ZMOD_RW,
+	"Default dnode indirect block shift");