Index: sys/kern/vfs_vnops.c.sav2
===================================================================
--- sys/kern/vfs_vnops.c.sav2
+++ sys/kern/vfs_vnops.c.sav2
@@ -3012,7 +3012,13 @@
 	size_t copylen, len, savlen;
 	char *dat;
 	long holein, holeout;
+	uint64_t curtime, stoptime;
+	struct timespec tm;
 
+	nanouptime(&tm);
+	stoptime = tm.tv_sec + 1;
+	stoptime = stoptime * 1000000000 + tm.tv_nsec;
+	curtime = 0;
 	holein = holeout = 0;
 	savlen = len = *lenp;
 	error = 0;
@@ -3095,7 +3101,7 @@
 	 * support holes on the server, but do not support FIOSEEKHOLE.
 	 */
 	eof = false;
-	while (len > 0 && error == 0 && !eof) {
+	while (len > 0 && error == 0 && !eof && curtime < stoptime) {
 		endoff = 0;			/* To shut up compilers. */
 		cantseek = true;
 		startoff = *inoffp;
@@ -3156,6 +3162,10 @@
 					*inoffp += xfer;
 					*outoffp += xfer;
 					len -= xfer;
+					nanouptime(&tm);
+					curtime = tm.tv_sec;
+					curtime = curtime * 1000000000 +
+					    tm.tv_nsec;
 				}
 			}
 			copylen = MIN(len, endoff - startoff);
@@ -3177,7 +3187,8 @@
 			xfer -= (*inoffp % blksize);
 		}
 		/* Loop copying the data block. */
-		while (copylen > 0 && error == 0 && !eof) {
+		while (copylen > 0 && error == 0 && !eof &&
+		    curtime < stoptime) {
 			if (copylen < xfer)
 				xfer = copylen;
 			error = vn_lock(invp, LK_SHARED);
@@ -3221,6 +3232,9 @@
 				}
 			}
 			xfer = blksize;
+			nanouptime(&tm);
+			curtime = tm.tv_sec;
+			curtime = curtime * 1000000000 + tm.tv_nsec;
 		}
 	}
 out: