Index: sys/contrib/openzfs/module/os/freebsd/zfs/zvol_os.c
===================================================================
--- sys/contrib/openzfs/module/os/freebsd/zfs/zvol_os.c
+++ sys/contrib/openzfs/module/os/freebsd/zfs/zvol_os.c
@@ -123,6 +123,7 @@
 		struct zvol_state_dev {
 			struct cdev *zsd_cdev;
 			uint64_t zsd_sync_cnt;
+			struct selinfo zsd_selinfo;
 		} _zso_dev;
 
 		/* volmode=geom */
@@ -167,6 +168,7 @@
 static d_read_t		zvol_cdev_read;
 static d_write_t	zvol_cdev_write;
 static d_strategy_t	zvol_geom_bio_strategy;
+static d_kqfilter_t	zvol_cdev_kqfilter;
 
 static struct cdevsw zvol_cdevsw = {
 	.d_name =	"zvol",
@@ -178,6 +180,16 @@
 	.d_read =	zvol_cdev_read,
 	.d_write =	zvol_cdev_write,
 	.d_strategy =	zvol_geom_bio_strategy,
+	.d_kqfilter =	zvol_cdev_kqfilter,
+};
+
+static void		zvol_filter_detach(struct knote *kn);
+static int		zvol_filter_vnode(struct knote *kn, long hint);
+
+static struct filterops zvol_filterops_vnode = {
+	.f_isfd = 1,
+	.f_detach = zvol_filter_detach,
+	.f_event = zvol_filter_vnode,
 };
 
 extern uint_t zfs_geom_probe_vdev_key;
@@ -592,6 +604,49 @@
 	return (1);
 }
 
+static void
+zvol_filter_detach(struct knote *kn)
+{
+	zvol_state_t *zv;
+	struct zvol_state_dev *zsd;
+
+	zv = kn->kn_hook;
+	zsd = &zv->zv_zso->zso_dev;
+
+	knlist_remove(&zsd->zsd_selinfo.si_note, kn, 0);
+}
+
+static int
+zvol_filter_vnode(struct knote *kn, long hint)
+{
+	kn->kn_fflags |= kn->kn_sfflags & hint;
+
+	return (kn->kn_fflags != 0);
+}
+
+static int
+zvol_cdev_kqfilter(struct cdev *dev, struct knote *kn)
+{
+	zvol_state_t *zv;
+	struct zvol_state_dev *zsd;
+
+	zv = dev->si_drv2;
+	zsd = &zv->zv_zso->zso_dev;
+
+	switch (kn->kn_filter) {
+	case EVFILT_VNODE:
+		kn->kn_fop = &zvol_filterops_vnode;
+		break;
+	default:
+		return (EINVAL);
+	}
+
+	kn->kn_hook = zv;
+	knlist_add(&zsd->zsd_selinfo.si_note, kn, 0);
+
+	return (0);
+}
+
 static void
 zvol_geom_bio_strategy(struct bio *bp)
 {
@@ -1281,6 +1336,9 @@
 		struct zvol_state_dev *zsd = &zv->zv_zso->zso_dev;
 		struct cdev *dev = zsd->zsd_cdev;
 
+		knlist_clear(&zsd->zsd_selinfo.si_note, 0);
+		knlist_destroy(&zsd->zsd_selinfo.si_note);
+
 		if (dev != NULL) {
 			ASSERT3P(dev->si_drv2, ==, NULL);
 			destroy_dev(dev);
@@ -1387,6 +1445,7 @@
 			dev->si_iosize_max = MAXPHYS;
 #endif
 			zsd->zsd_cdev = dev;
+			knlist_init_sx(&zsd->zsd_selinfo.si_note, &zv->zv_state_lock);
 		}
 	}
 	(void) strlcpy(zv->zv_name, name, MAXPATHLEN);
@@ -1491,6 +1550,10 @@
 			g_resize_provider(pp, zv->zv_volsize);
 
 		g_topology_unlock();
+	} else if (zv->zv_volmode == ZFS_VOLMODE_DEV) {
+		struct zvol_state_dev *zsd = &zv->zv_zso->zso_dev;
+
+		KNOTE_UNLOCKED(&zsd->zsd_selinfo.si_note, NOTE_ATTRIB);
 	}
 	return (0);
 }