Fix updating the zvol_htable when renaming a zvol

When renaming a zvol, insert it into zvol_htable using the new name, not
the old name.  Otherwise some operations won't work.  For example,
"zfs set volsize" while the zvol is open.

Sponsored by:	Axcient
Signed-off-by:	Alan Somers <asomers@FreeBSD.org>
Closes openzfs#16127

module/os/freebsd/zfs/zvol_os.c

@@ -1259,7 +1259,7 @@ zvol_os_rename_minor(zvol_state_t *zv, const char *newname)
 	ASSERT(MUTEX_HELD(&zv->zv_state_lock));
 
 	/* Move to a new hashtable entry.  */
-	zv->zv_hash = zvol_name_hash(zv->zv_name);
+	zv->zv_hash = zvol_name_hash(newname);
 	hlist_del(&zv->zv_hlink);
 	hlist_add_head(&zv->zv_hlink, ZVOL_HT_HEAD(zv->zv_hash));
 

module/os/linux/zfs/zvol_os.c

@@ -1571,7 +1571,7 @@ zvol_os_rename_minor(zvol_state_t *zv, const char *newname)
 	strlcpy(zv->zv_name, newname, sizeof (zv->zv_name));
 
 	/* move to new hashtable entry  */
-	zv->zv_hash = zvol_name_hash(zv->zv_name);
+	zv->zv_hash = zvol_name_hash(newname);
 	hlist_del(&zv->zv_hlink);
 	hlist_add_head(&zv->zv_hlink, ZVOL_HT_HEAD(zv->zv_hash));