Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c	(wersja 251746)
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c	(kopia robocza)
@@ -1337,8 +1337,13 @@
 	zio_execute(zio);
 
 	mutex_enter(&zio->io_lock);
-	while (zio->io_executor != NULL)
-		cv_wait(&zio->io_cv, &zio->io_lock);
+	while (zio->io_executor != NULL) {
+		if (cv_timedwait(&zio->io_cv, &zio->io_lock, hz * 15) ==
+		    EWOULDBLOCK) {
+			printf("%s:%u: zio=%p taking more than 15s (io_stage=%d).",
+			    __func__, __LINE__, zio, zio->io_stage);
+		}
+	}
 	mutex_exit(&zio->io_lock);
 
 	error = zio->io_error;