diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 86a2b8b57d..666eec36d3 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -3476,7 +3476,7 @@ l2:
 		 * overhead would be unchanged, that doesn't seem necessarily
 		 * worthwhile.
 		 */
-		if (PageIsAllVisible(BufferGetPage(buffer)) &&
+		if (PageIsAllVisible(page) &&
 			visibilitymap_clear(relation, block, vmbuffer,
 								VISIBILITYMAP_ALL_FROZEN))
 			cleared_all_frozen = true;
@@ -3538,36 +3538,46 @@ l2:
 		 * first".  To implement this, we must do RelationGetBufferForTuple
 		 * while not holding the lock on the old page, and we must rely on it
 		 * to get the locks on both pages in the correct order.
+		 *
+		 * Another consideration is that we need visibility map page pin(s) if
+		 * we will have to clear the all-visible flag on either page.  If we
+		 * call RelationGetBufferForTuple, we rely on it to acquire any such
+		 * pins; but if we don't, we have to handle that here.  Hence we need
+		 * a loop.
 		 */
-		if (newtupsize > pagefree)
-		{
-			/* Assume there's no chance to put heaptup on same page. */
-			newbuf = RelationGetBufferForTuple(relation, heaptup->t_len,
-											   buffer, 0, NULL,
-											   &vmbuffer_new, &vmbuffer);
-		}
-		else
+		for (;;)
 		{
+			if (newtupsize > pagefree)
+			{
+				/* It doesn't fit, must use RelationGetBufferForTuple. */
+				newbuf = RelationGetBufferForTuple(relation, heaptup->t_len,
+												   buffer, 0, NULL,
+												   &vmbuffer_new, &vmbuffer);
+				/* We're all done. */
+				break;
+			}
+			/* Acquire VM page pin if needed and we don't have it. */
+			if (vmbuffer == InvalidBuffer && PageIsAllVisible(page))
+				visibilitymap_pin(relation, block, &vmbuffer);
 			/* Re-acquire the lock on the old tuple's page. */
 			LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 			/* Re-check using the up-to-date free space */
 			pagefree = PageGetHeapFreeSpace(page);
-			if (newtupsize > pagefree)
+			if (newtupsize > pagefree ||
+				(vmbuffer == InvalidBuffer && PageIsAllVisible(page)))
 			{
 				/*
-				 * Rats, it doesn't fit anymore.  We must now unlock and
-				 * relock to avoid deadlock.  Fortunately, this path should
-				 * seldom be taken.
+				 * Rats, it doesn't fit anymore, or somebody just now set the
+				 * all-visible flag.  We must now unlock and loop to avoid
+				 * deadlock.  Fortunately, this path should seldom be taken.
 				 */
 				LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
-				newbuf = RelationGetBufferForTuple(relation, heaptup->t_len,
-												   buffer, 0, NULL,
-												   &vmbuffer_new, &vmbuffer);
 			}
 			else
 			{
-				/* OK, it fits here, so we're done. */
+				/* We're all done. */
 				newbuf = buffer;
+				break;
 			}
 		}
 	}
diff --git a/src/backend/access/heap/hio.c b/src/backend/access/heap/hio.c
index d41d318eef..cf2d7743b5 100644
--- a/src/backend/access/heap/hio.c
+++ b/src/backend/access/heap/hio.c
@@ -284,9 +284,13 @@ RelationAddExtraBlocks(Relation relation, BulkInsertState bistate)
  *	happen if space is freed in that page after heap_update finds there's not
  *	enough there).  In that case, the page will be pinned and locked only once.
  *
- *	For the vmbuffer and vmbuffer_other arguments, we avoid deadlock by
- *	locking them only after locking the corresponding heap page, and taking
- *	no further lwlocks while they are locked.
+ *	We also handle the possibility that the all-visible flag will need to be
+ *	cleared on one or both pages.  If so, pin on the associated visibility map
+ *	page must be acquired before acquiring buffer lock(s), to avoid possibly
+ *	doing I/O while holding buffer locks.  The pins are passed back to the
+ *	caller using the input-output arguments vmbuffer and vmbuffer_other.
+ *	Note that in some cases the caller might have already acquired such pins,
+ *	which is indicated by these arguments not being InvalidBuffer on entry.
  *
  *	We normally use FSM to help us find free space.  However,
  *	if HEAP_INSERT_SKIP_FSM is specified, we just append a new empty page to
@@ -631,6 +635,8 @@ loop:
 	if (otherBuffer != InvalidBuffer)
 	{
 		Assert(otherBuffer != buffer);
+		targetBlock = BufferGetBlockNumber(buffer);
+		Assert(targetBlock > otherBlock);
 
 		if (unlikely(!ConditionalLockBuffer(otherBuffer)))
 		{
@@ -639,10 +645,16 @@ loop:
 			LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 
 			/*
-			 * Because the buffer was unlocked for a while, it's possible,
-			 * although unlikely, that the page was filled. If so, just retry
-			 * from start.
+			 * Because the buffers were unlocked for a while, it's possible,
+			 * although unlikely, that an all-visible flag became set or that
+			 * somebody used up the available space in the new page.  We can
+			 * use GetVisibilityMapPins to deal with the first case.  In the
+			 * second case, just retry from start.
 			 */
+			GetVisibilityMapPins(relation, otherBuffer, buffer,
+								 otherBlock, targetBlock, vmbuffer_other,
+								 vmbuffer);
+
 			if (len > PageGetHeapFreeSpace(page))
 			{
 				LockBuffer(otherBuffer, BUFFER_LOCK_UNLOCK);