Keep track of mixed nonrotational (ssd+hdd) devices.

Only mirrors are mixed.  If a pool consist of several mixed vdevs, it is
mixed if all vdevs are either mixed, or fully nonrotational.

Do not mark as mixed when fully nonrotational.

include/sys/vdev_impl.h

@@ -159,6 +159,7 @@ struct vdev {
 	boolean_t	vdev_expanding;	/* expand the vdev?		*/
 	boolean_t	vdev_reopening;	/* reopen in progress?		*/
 	boolean_t	vdev_nonrot;	/* true if solid state		*/
+	boolean_t	vdev_nonrot_mix; /* true if partial solid state	*/
 	int		vdev_open_error; /* error on last open		*/
 	kthread_t	*vdev_open_thread; /* thread opening children	*/
 	uint64_t	vdev_crtxg;	/* txg when top-level was added */

module/zfs/vdev.c

@@ -1173,6 +1173,7 @@ vdev_open_children(vdev_t *vd)
 	taskq_t *tq;
 	int children = vd->vdev_children;
 	int c;
+	boolean_t nonrot_some;
 
 	/*
 	 * in order to handle pools on top of zvols, do the opens
@@ -1198,9 +1199,19 @@ vdev_open_children(vdev_t *vd)
 	}
 
 	vd->vdev_nonrot = B_TRUE;
+	vd->vdev_nonrot_mix = B_TRUE;
+	nonrot_some = B_FALSE;
 
-	for (c = 0; c < children; c++)
+	for (c = 0; c < children; c++) {
 		vd->vdev_nonrot &= vd->vdev_child[c]->vdev_nonrot;
+		vd->vdev_nonrot_mix &= vd->vdev_child[c]->vdev_nonrot_mix |
+		    vd->vdev_child[c]->vdev_nonrot;
+		nonrot_some |= vd->vdev_child[c]->vdev_nonrot;
+	}
+	if (vd->vdev_ops == &vdev_mirror_ops)
+		vd->vdev_nonrot_mix |= nonrot_some;
+	if (vd->vdev_nonrot)
+		vd->vdev_nonrot_mix = B_FALSE;
 }
 
 /*

module/zfs/vdev_disk.c

@@ -321,6 +321,7 @@ vdev_disk_open(vdev_t *v, uint64_t *psize, uint64_t *max_psize,
 
 	/* Inform the ZIO pipeline that we are non-rotational */
 	v->vdev_nonrot = blk_queue_nonrot(bdev_get_queue(vd->vd_bdev));
+	v->vdev_nonrot_mix = B_FALSE;
 
 	/* Physical volume size in bytes */
 	*psize = bdev_capacity(vd->vd_bdev);

module/zfs/vdev_file.c

@@ -60,6 +60,7 @@ vdev_file_open(vdev_t *vd, uint64_t *psize, uint64_t *max_psize,
 
 	/* Rotational optimizations only make sense on block devices */
 	vd->vdev_nonrot = B_TRUE;
+	vd->vdev_nonrot_mix = B_FALSE;
 
 	/*
 	 * We must have a pathname, and it must be absolute.