diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
index 180ac4f..e1cf4ae 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
@@ -323,8 +323,17 @@ page_lookup(vnode_t *vp, int64_t start, int64_t off, int64_t nbytes)
 	for (;;) {
 		if ((pp = vm_page_lookup(obj, OFF_TO_IDX(start))) != NULL &&
 		    vm_page_is_valid(pp, (vm_offset_t)off, nbytes)) {
-			if (vm_page_sleep_if_busy(pp, FALSE, "zfsmwb"))
+			if ((pp->oflags & VPO_BUSY) != 0) {
+				/*
+				 * Reference the page before unlocking and
+				 * sleeping so that the page daemon is less
+				 * likely to reclaim it.
+				 */
+				vm_page_lock_queues();
+				vm_page_flag_set(pp, PG_REFERENCED);
+				vm_page_sleep(pp, "zfsmwb");
 				continue;
+			}
 			vm_page_busy(pp);
 			vm_page_lock_queues();
 			vm_page_undirty(pp);
@@ -380,7 +389,7 @@ update_pages(vnode_t *vp, int64_t start, int len, objset_t *os, uint64_t oid,
 {
 	vm_object_t obj;
 	struct sf_buf *sf;
-	int64_t off;
+	int off;
 
 	ASSERT(vp->v_mount != NULL);
 	obj = vp->v_object;
@@ -390,7 +399,7 @@ update_pages(vnode_t *vp, int64_t start, int len, objset_t *os, uint64_t oid,
 	VM_OBJECT_LOCK(obj);
 	for (start &= PAGEMASK; len > 0; start += PAGESIZE) {
 		vm_page_t pp;
-		uint64_t nbytes = MIN(PAGESIZE - off, len);
+		int nbytes = MIN(PAGESIZE - off, len);
 
 		if ((pp = page_lookup(vp, start, off, nbytes)) != NULL) {
 			caddr_t va;
@@ -433,9 +442,10 @@ mappedread(vnode_t *vp, int nbytes, uio_t *uio)
 	vm_object_t obj;
 	vm_page_t m;
 	struct sf_buf *sf;
-	int64_t start, off;
+	int64_t start;
 	caddr_t va;
 	int len = nbytes;
+	int off;
 	int error = 0;
 	uint64_t dirbytes;
 
@@ -448,13 +458,23 @@ mappedread(vnode_t *vp, int nbytes, uio_t *uio)
 	dirbytes = 0;
 	VM_OBJECT_LOCK(obj);
 	for (start &= PAGEMASK; len > 0; start += PAGESIZE) {
-		uint64_t bytes = MIN(PAGESIZE - off, len);
+		int bytes = MIN(PAGESIZE - off, len);
 
 again:
 		if ((m = vm_page_lookup(obj, OFF_TO_IDX(start))) != NULL &&
-		    vm_page_is_valid(m, (vm_offset_t)off, bytes)) {
-			if (vm_page_sleep_if_busy(m, FALSE, "zfsmrb"))
+		    vm_page_is_valid(m, off, bytes)) {
+			if ((m->oflags & VPO_BUSY) != 0) {
+				/*
+				 * Reference the page before unlocking and
+				 * sleeping so that the page daemon is less
+				 * likely to reclaim it.
+				 */
+				vm_page_lock_queues();
+				vm_page_flag_set(m, PG_REFERENCED);
+				vm_page_sleep(m, "zfsmrb");
 				goto again;
+			}
+
 			vm_page_busy(m);
 			VM_OBJECT_UNLOCK(obj);
 			if (dirbytes > 0) {
@@ -462,14 +482,8 @@ again:
 				    dirbytes);
 				dirbytes = 0;
 			}
-			if (error == 0) {
-				sched_pin();
-				sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
-				va = (caddr_t)sf_buf_kva(sf);
-				error = uiomove(va + off, bytes, UIO_READ, uio);
-				sf_buf_free(sf);
-				sched_unpin();
-			}
+			if (error == 0)
+				uiomove_fromphys(&m, off, bytes, uio);
 			VM_OBJECT_LOCK(obj);
 			vm_page_wakeup(m);
 		} else if (m != NULL && uio->uio_segflg == UIO_NOCOPY) {
@@ -480,8 +494,17 @@ again:
 			 * but it pessimize performance of sendfile/UFS, that's
 			 * why I handle this special case in ZFS code.
 			 */
-			if (vm_page_sleep_if_busy(m, FALSE, "zfsmrb"))
+			if ((m->oflags & VPO_BUSY) != 0) {
+				/*
+				 * Reference the page before unlocking and
+				 * sleeping so that the page daemon is less
+				 * likely to reclaim it.
+				 */
+				vm_page_lock_queues();
+				vm_page_flag_set(m, PG_REFERENCED);
+				vm_page_sleep(m, "zfsmrb");
 				goto again;
+			}
 			vm_page_busy(m);
 			VM_OBJECT_UNLOCK(obj);
 			if (dirbytes > 0) {
@@ -500,6 +523,8 @@ again:
 				sched_unpin();
 			}
 			VM_OBJECT_LOCK(obj);
+			if (error == 0)
+				vm_page_set_valid(m, off, bytes);
 			vm_page_wakeup(m);
 			if (error == 0)
 				uio->uio_resid -= bytes;
@@ -918,7 +943,8 @@ again:
 #if 0
 		if (tx_bytes && vn_has_cached_data(vp))
 #else
-		if (tx_bytes && vp->v_object != NULL)
+		if (tx_bytes && vp->v_object != NULL && (vp->v_object->resident_page_count > 0
+							 || vp->v_object->cache != NULL))
 #endif
 		{
 			update_pages(vp, woff, tx_bytes, zfsvfs->z_os,