diff --git a/include/sys/vdev_impl.h b/include/sys/vdev_impl.h
index fd6eddc0444d..6dae2955b847 100644
--- a/include/sys/vdev_impl.h
+++ b/include/sys/vdev_impl.h
@@ -60,7 +60,7 @@ typedef int	vdev_open_func_t(vdev_t *vd, uint64_t *size, uint64_t *max_size,
     uint64_t *ashift);
 typedef void	vdev_close_func_t(vdev_t *vd);
 typedef uint64_t vdev_asize_func_t(vdev_t *vd, uint64_t psize);
-typedef void	vdev_io_start_func_t(zio_t *zio);
+typedef int	vdev_io_start_func_t(zio_t *zio);
 typedef void	vdev_io_done_func_t(zio_t *zio);
 typedef void	vdev_state_change_func_t(vdev_t *vd, int, int);
 typedef void	vdev_hold_func_t(vdev_t *vd);
diff --git a/include/sys/zio.h b/include/sys/zio.h
index 350063c739b8..e1b1b8c705cc 100644
--- a/include/sys/zio.h
+++ b/include/sys/zio.h
@@ -154,6 +154,9 @@ typedef enum zio_priority {
 	ZIO_PRIORITY_NOW		/* non-queued i/os (e.g. free) */
 } zio_priority_t;
 
+#define	ZIO_PIPELINE_CONTINUE		0x100
+#define	ZIO_PIPELINE_STOP		0x101
+
 enum zio_flag {
 	/*
 	 * Flags inherited by gang, ddt, and vdev children,
diff --git a/lib/libzpool/taskq.c b/lib/libzpool/taskq.c
index d63bc28e2379..72807f6a3d08 100644
--- a/lib/libzpool/taskq.c
+++ b/lib/libzpool/taskq.c
@@ -25,7 +25,6 @@
 /*
  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
  * Copyright 2012 Garrett D'Amore <garrett@damore.org>.  All rights reserved.
- * Copyright (c) 2014 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -34,10 +33,8 @@ int taskq_now;
 taskq_t *system_taskq;
 
 #define	TASKQ_ACTIVE	0x00010000
-#define	TASKQ_NAMELEN	31
 
 struct taskq {
-	char		tq_name[TASKQ_NAMELEN + 1];
 	kmutex_t	tq_lock;
 	krwlock_t	tq_threadlock;
 	kcondvar_t	tq_dispatch_cv;
@@ -283,7 +280,6 @@ taskq_create(const char *name, int nthreads, pri_t pri,
 	cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
 	cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
 	cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
-	(void) strncpy(tq->tq_name, name, TASKQ_NAMELEN + 1);
 	tq->tq_flags = flags | TASKQ_ACTIVE;
 	tq->tq_active = nthreads;
 	tq->tq_nthreads = nthreads;
diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c
index 0bd13fd81741..6dfaf2578daa 100644
--- a/module/zfs/vdev_disk.c
+++ b/module/zfs/vdev_disk.c
@@ -671,7 +671,7 @@ vdev_disk_io_flush(struct block_device *bdev, zio_t *zio)
 	return (0);
 }
 
-static void
+static int
 vdev_disk_io_start(zio_t *zio)
 {
 	vdev_t *v = zio->io_vd;
@@ -683,9 +683,7 @@ vdev_disk_io_start(zio_t *zio)
 
 		if (!vdev_readable(v)) {
 			zio->io_error = SET_ERROR(ENXIO);
-			zio_interrupt(zio);
-			return;
-
+			return (ZIO_PIPELINE_CONTINUE);
 		}
 
 		switch (zio->io_cmd) {
@@ -701,7 +699,7 @@ vdev_disk_io_start(zio_t *zio)
 
 			error = vdev_disk_io_flush(vd->vd_bdev, zio);
 			if (error == 0)
-				return;
+				return (ZIO_PIPELINE_STOP);
 
 			zio->io_error = error;
 			if (error == ENOTSUP)
@@ -713,8 +711,8 @@ vdev_disk_io_start(zio_t *zio)
 			zio->io_error = SET_ERROR(ENOTSUP);
 		}
 
-		zio_execute(zio);
-		return;
+		return (ZIO_PIPELINE_CONTINUE);
+
 	case ZIO_TYPE_WRITE:
 		flags = WRITE;
 		break;
@@ -725,17 +723,17 @@ vdev_disk_io_start(zio_t *zio)
 
 	default:
 		zio->io_error = SET_ERROR(ENOTSUP);
-		zio_interrupt(zio);
-		return;
+		return (ZIO_PIPELINE_CONTINUE);
 	}
 
 	error = __vdev_disk_physio(vd->vd_bdev, zio, NULL,
 	    zio->io_size, zio->io_offset, flags);
 	if (error) {
 		zio->io_error = error;
-		zio_interrupt(zio);
-		return;
+		return (ZIO_PIPELINE_CONTINUE);
 	}
+
+	return (ZIO_PIPELINE_STOP);
 }
 
 static void
diff --git a/module/zfs/vdev_file.c b/module/zfs/vdev_file.c
index 6420e0bc6823..296e27ebd889 100644
--- a/module/zfs/vdev_file.c
+++ b/module/zfs/vdev_file.c
@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -183,7 +183,7 @@ vdev_file_io_fsync(void *arg)
 	zio_interrupt(zio);
 }
 
-static void
+static int
 vdev_file_io_start(zio_t *zio)
 {
 	vdev_t *vd = zio->io_vd;
@@ -193,8 +193,7 @@ vdev_file_io_start(zio_t *zio)
 		/* XXPOLICY */
 		if (!vdev_readable(vd)) {
 			zio->io_error = SET_ERROR(ENXIO);
-			zio_interrupt(zio);
-			return;
+			return (ZIO_PIPELINE_CONTINUE);
 		}
 
 		switch (zio->io_cmd) {
@@ -223,12 +222,13 @@ vdev_file_io_start(zio_t *zio)
 			zio->io_error = SET_ERROR(ENOTSUP);
 		}
 
-		zio_execute(zio);
-		return;
+		return (ZIO_PIPELINE_CONTINUE);
 	}
 
 	VERIFY3U(taskq_dispatch(vdev_file_taskq, vdev_file_io_strategy, zio,
 	    TQ_SLEEP), !=, 0);
+
+	return (ZIO_PIPELINE_STOP);
 }
 
 /* ARGSUSED */
diff --git a/module/zfs/vdev_mirror.c b/module/zfs/vdev_mirror.c
index 13074680dbe9..bbdf923f1692 100644
--- a/module/zfs/vdev_mirror.c
+++ b/module/zfs/vdev_mirror.c
@@ -24,7 +24,7 @@
  */
 
 /*
- * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -326,7 +326,7 @@ vdev_mirror_child_select(zio_t *zio)
 	return (-1);
 }
 
-static void
+static int
 vdev_mirror_io_start(zio_t *zio)
 {
 	mirror_map_t *mm;
@@ -357,8 +357,7 @@ vdev_mirror_io_start(zio_t *zio)
 				    zio->io_type, zio->io_priority, 0,
 				    vdev_mirror_scrub_done, mc));
 			}
-			zio_execute(zio);
-			return;
+			return (ZIO_PIPELINE_CONTINUE);
 		}
 		/*
 		 * For normal reads just pick one child.
@@ -384,7 +383,7 @@ vdev_mirror_io_start(zio_t *zio)
 		c++;
 	}
 
-	zio_execute(zio);
+	return (ZIO_PIPELINE_CONTINUE);
 }
 
 static int
diff --git a/module/zfs/vdev_missing.c b/module/zfs/vdev_missing.c
index 228757334234..b9eb99d18005 100644
--- a/module/zfs/vdev_missing.c
+++ b/module/zfs/vdev_missing.c
@@ -24,7 +24,7 @@
  */
 
 /*
- * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 /*
@@ -66,11 +66,11 @@ vdev_missing_close(vdev_t *vd)
 }
 
 /* ARGSUSED */
-static void
+static int
 vdev_missing_io_start(zio_t *zio)
 {
 	zio->io_error = SET_ERROR(ENOTSUP);
-	zio_execute(zio);
+	return (ZIO_PIPELINE_CONTINUE);
 }
 
 /* ARGSUSED */
diff --git a/module/zfs/vdev_raidz.c b/module/zfs/vdev_raidz.c
index 07ddc2df63b8..bdf4171445cd 100644
--- a/module/zfs/vdev_raidz.c
+++ b/module/zfs/vdev_raidz.c
@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -1722,7 +1722,7 @@ vdev_raidz_child_done(zio_t *zio)
  *      vdevs have had errors, then create zio read operations to the parity
  *      columns' VDevs as well.
  */
-static void
+static int
 vdev_raidz_io_start(zio_t *zio)
 {
 	vdev_t *vd = zio->io_vd;
@@ -1766,8 +1766,7 @@ vdev_raidz_io_start(zio_t *zio)
 			    ZIO_FLAG_NODATA | ZIO_FLAG_OPTIONAL, NULL, NULL));
 		}
 
-		zio_execute(zio);
-		return;
+		return (ZIO_PIPELINE_CONTINUE);
 	}
 
 	ASSERT(zio->io_type == ZIO_TYPE_READ);
@@ -1807,7 +1806,7 @@ vdev_raidz_io_start(zio_t *zio)
 		}
 	}
 
-	zio_execute(zio);
+	return (ZIO_PIPELINE_CONTINUE);
 }
 
 
diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 6b0a4a58e9ab..87342090a0dc 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -59,9 +59,6 @@ kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
 kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
 int zio_delay_max = ZIO_DELAY_MAX;
 
-#define	ZIO_PIPELINE_CONTINUE		0x100
-#define	ZIO_PIPELINE_STOP		0x101
-
 /*
  * The following actions directly effect the spa's sync-to-convergence logic.
  * The values below define the sync pass when we start performing the action.
@@ -2611,18 +2608,6 @@ zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp)
  * Read and write to physical devices
  * ==========================================================================
  */
-
-
-/*
- * Issue an I/O to the underlying vdev. Typically the issue pipeline
- * stops after this stage and will resume upon I/O completion.
- * However, there are instances where the vdev layer may need to
- * continue the pipeline when an I/O was not issued. Since the I/O
- * that was sent to the vdev layer might be different than the one
- * currently active in the pipeline (see vdev_queue_io()), we explicitly
- * force the underlying vdev layers to call either zio_execute() or
- * zio_interrupt() to ensure that the pipeline continues with the correct I/O.
- */
 static int
 zio_vdev_io_start(zio_t *zio)
 {
@@ -2640,8 +2625,7 @@ zio_vdev_io_start(zio_t *zio)
 		/*
 		 * The mirror_ops handle multiple DVAs in a single BP.
 		 */
-		vdev_mirror_ops.vdev_op_io_start(zio);
-		return (ZIO_PIPELINE_STOP);
+		return (vdev_mirror_ops.vdev_op_io_start(zio));
 	}
 
 	/*
@@ -2649,7 +2633,7 @@ zio_vdev_io_start(zio_t *zio)
 	 * can quickly react to certain workloads.  In particular, we care
 	 * about non-scrubbing, top-level reads and writes with the following
 	 * characteristics:
-	 *	- synchronous writes of user data to non-slog devices
+	 * 	- synchronous writes of user data to non-slog devices
 	 *	- any reads of user data
 	 * When these conditions are met, adjust the timestamp of spa_last_io
 	 * which allows the scan thread to adjust its workload accordingly.
@@ -2739,8 +2723,7 @@ zio_vdev_io_start(zio_t *zio)
 		}
 	}
 
-	vd->vdev_ops->vdev_op_io_start(zio);
-	return (ZIO_PIPELINE_STOP);
+	return (vd->vdev_ops->vdev_op_io_start(zio));
 }
 
 static int