diff --git a/include/sys/vdev.h b/include/sys/vdev.h
index 5885d50cc489..35a29ed095dc 100644
--- a/include/sys/vdev.h
+++ b/include/sys/vdev.h
@@ -46,6 +46,7 @@ typedef enum vdev_dtl_type {
 
 extern int zfs_nocacheflush;
 extern int zfs_notrim;
+extern int zfs_trim_zero;
 
 extern int vdev_open(vdev_t *);
 extern void vdev_open_children(vdev_t *);
diff --git a/module/zfs/vdev.c b/module/zfs/vdev.c
index 6b9aa733bcd8..3c399ae030df 100644
--- a/module/zfs/vdev.c
+++ b/module/zfs/vdev.c
@@ -64,6 +64,15 @@ static vdev_ops_t *vdev_ops_table[] = {
 /* maximum scrub/resilver I/O queue per leaf vdev */
 int zfs_scrub_limit = 10;
 
+/*
+ * Make sure TRIM zeroes data.
+ *
+ * On disk vdevs, don't use DISCARD and write zero pages instead.
+ *
+ * On file vdevs, if hole punching fails, then write zeroes instead.
+ */
+int zfs_trim_zero = 0;
+
 /*
  * Given a vdev type, return the appropriate ops vector.
  */
@@ -3200,4 +3209,7 @@ EXPORT_SYMBOL(vdev_clear);
 
 module_param(zfs_scrub_limit, int, 0644);
 MODULE_PARM_DESC(zfs_scrub_limit, "Max scrub/resilver I/O per leaf vdev");
+
+module_param(zfs_trim_zero, int, 0644);
+MODULE_PARM_DESC(zfs_trim_zero, "Make sure TRIM zeroes data (only for debugging)");
 #endif
diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c
index 6edabcd6c45d..dbab8992f613 100644
--- a/module/zfs/vdev_disk.c
+++ b/module/zfs/vdev_disk.c
@@ -494,15 +494,22 @@ __vdev_disk_physio(struct block_device *bdev, zio_t *zio, caddr_t kbuf_ptr,
 	if (flags & REQ_DISCARD) {
 		ASSERT(!kbuf_ptr);
 
-		if (!blk_queue_discard(q) ||
-		    !q->limits.max_discard_sectors)
-			return EOPNOTSUPP;
-
-		max_discard_size = MIN(q->limits.max_discard_sectors << 9,
-		    INT_MAX);
-		if (q->limits.discard_granularity)
-			max_discard_size &= ~(q->limits.discard_granularity - 1);
-		max_discard_size &= ~511;
+		if (zfs_trim_zero)
+			max_discard_size = PAGE_SIZE;
+		else {
+			if (!blk_queue_discard(q) ||
+			    !q->limits.max_discard_sectors)
+				return EOPNOTSUPP;
+
+			max_discard_size = MIN(
+			    q->limits.max_discard_sectors << 9,
+			    INT_MAX);
+			if (q->limits.discard_granularity)
+				max_discard_size &=
+				     ~(q->limits.discard_granularity
+				         - 1);
+			max_discard_size &= ~511;
+		}
 	}
 
 	ASSERT3U(kbuf_offset + kbuf_size, <=, bdev->bd_inode->i_size);
@@ -563,8 +570,14 @@ __vdev_disk_physio(struct block_device *bdev, zio_t *zio, caddr_t kbuf_ptr,
 		dr->dr_bio[i]->bi_private = dr;
 
 		if (flags & REQ_DISCARD) {
-			dr->dr_bio[i]->bi_size = MIN(bio_size,
-			     max_discard_size);
+			if (zfs_trim_zero) {
+				dr->dr_bio[i]->bi_rw &= ~REQ_DISCARD;
+				bio_add_page(dr->dr_bio[i],
+				    ZERO_PAGE(0), MIN(bio_size,
+				    max_discard_size), 0);
+			} else
+				dr->dr_bio[i]->bi_size = MIN(bio_size,
+				     max_discard_size);
 			bio_size -= dr->dr_bio[i]->bi_size;
 		} else {
 			/*
diff --git a/module/zfs/vdev_file.c b/module/zfs/vdev_file.c
index 9ff6b6e80c1f..57ca54535b4e 100644
--- a/module/zfs/vdev_file.c
+++ b/module/zfs/vdev_file.c
@@ -30,6 +30,10 @@
 #include <sys/fs/zfs.h>
 #include <sys/fm/fs/zfs.h>
 
+#ifndef _KERNEL
+static char empty_zero_page[4096];
+#endif
+
 /*
  * Virtual device vector for files.
  */
@@ -137,13 +141,55 @@ vdev_file_close(vdev_t *vd)
 	vd->vdev_tsd = NULL;
 }
 
+static void vdev_file_trim(zio_t *zio)
+{
+	struct flock fl;
+	uint64_t len;
+	ssize_t resid = 0;
+	vdev_t *vd = zio->io_vd;
+	vdev_file_t *vf = vd->vdev_tsd;
+
+	if (vd->vdev_notrim) {
+		zio->io_error = EOPNOTSUPP;
+		return;
+	}
+
+	bzero(&fl, sizeof(fl));
+	fl.l_type = F_WRLCK;
+	fl.l_whence = 0;
+	fl.l_start = zio->io_offset;
+	fl.l_len = zio->io_size;
+	zio->io_error = VOP_SPACE(vf->vf_vnode, F_FREESP, &fl,
+	    FWRITE | FOFFMAX, zio->io_offset, kcred, NULL);
+
+	if (zfs_trim_zero && zio->io_error) {
+		while (fl.l_len > 0) {
+			len = MIN(fl.l_len, sizeof(empty_zero_page));
+
+			zio->io_error = vn_rdwr(UIO_WRITE, vf->vf_vnode,
+			    empty_zero_page, len, fl.l_start,
+			    UIO_SYSSPACE, 0, RLIM64_INFINITY, kcred,
+			    &resid);
+			if (resid != 0 && zio->io_error == 0)
+				zio->io_error = ENOSPC;
+			if (zio->io_error)
+				return;
+
+			fl.l_len -= len;
+			fl.l_start += len;
+		}
+	}
+
+	if (zio->io_error == EOPNOTSUPP)
+		vd->vdev_notrim = B_TRUE;
+}
+
 static int
 vdev_file_io_start(zio_t *zio)
 {
 	vdev_t *vd = zio->io_vd;
 	vdev_file_t *vf;
 	ssize_t resid = 0;
-	struct flock fl;
 
 	if (!vdev_readable(vd)) {
 		zio->io_error = ENXIO;
@@ -159,19 +205,7 @@ vdev_file_io_start(zio_t *zio)
 			    kcred, NULL);
 			break;
 		case DKIOCTRIM:
-			if (vd->vdev_notrim)
-				zio->io_error = EOPNOTSUPP;
-			else {
-				bzero(&fl, sizeof(fl));
-				fl.l_type = F_WRLCK;
-				fl.l_whence = 0;
-				fl.l_start = zio->io_offset;
-				fl.l_len = zio->io_size;
-				zio->io_error = VOP_SPACE(vf->vf_vnode, F_FREESP, &fl,
-				    FWRITE | FOFFMAX, zio->io_offset, kcred, NULL);
-				if (zio->io_error == EOPNOTSUPP)
-					vd->vdev_notrim = B_TRUE;
-			}
+			vdev_file_trim(zio);
 			break;
 		default:
 			zio->io_error = ENOTSUP;