Illumos #5244 - zio pipeline callers should explicitly invoke next stage

5244 zio pipeline callers should explicitly invoke next stage
Reviewed by: Adam Leventhal <[email protected]>
Reviewed by: Alex Reece <[email protected]>
Reviewed by: Christopher Siden <[email protected]>
Reviewed by: Matthew Ahrens <[email protected]>
Reviewed by: Richard Elling <[email protected]>
Reviewed by: Dan McDonald <[email protected]>
Reviewed by: Steven Hartland <[email protected]>
Approved by: Gordon Ross <[email protected]>

References:
  https://www.illumos.org/issues/5244
  https://github.com/illumos/illumos-gate/commit/738f37b

Porting Notes:

1. The unported "2932 support crash dumps to raidz, etc. pools"
   caused a merge conflict due to a copyright difference in
   module/zfs/vdev_raidz.c.
2. The unported "4128 disks in zpools never go away when pulled"
   and additional Linux-specific changes caused merge conflicts in
   module/zfs/vdev_disk.c.

Ported-by: Richard Yao <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #2828

6 files changed, 50 insertions, 30 deletions

diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c
index 7f2263457..db13b7bc4 100644
--- a/module/zfs/vdev_disk.c
+++ b/module/zfs/vdev_disk.c
@@ -657,7 +657,7 @@ vdev_disk_io_flush(struct block_device *bdev, zio_t *zio)
 	return (0);
 }
 
-static int
+static void
 vdev_disk_io_start(zio_t *zio)
 {
 	vdev_t *v = zio->io_vd;
@@ -669,7 +669,8 @@ vdev_disk_io_start(zio_t *zio)
 
 		if (!vdev_readable(v)) {
 			zio->io_error = SET_ERROR(ENXIO);
-			return (ZIO_PIPELINE_CONTINUE);
+			zio_interrupt(zio);
+			return;
 		}
 
 		switch (zio->io_cmd) {
@@ -685,7 +686,7 @@ vdev_disk_io_start(zio_t *zio)
 
 			error = vdev_disk_io_flush(vd->vd_bdev, zio);
 			if (error == 0)
-				return (ZIO_PIPELINE_STOP);
+				return;
 
 			zio->io_error = error;
 			if (error == ENOTSUP)
@@ -697,8 +698,8 @@ vdev_disk_io_start(zio_t *zio)
 			zio->io_error = SET_ERROR(ENOTSUP);
 		}
 
-		return (ZIO_PIPELINE_CONTINUE);
-
+		zio_execute(zio);
+		return;
 	case ZIO_TYPE_WRITE:
 		flags = WRITE;
 		break;
@@ -709,17 +710,17 @@ vdev_disk_io_start(zio_t *zio)
 
 	default:
 		zio->io_error = SET_ERROR(ENOTSUP);
-		return (ZIO_PIPELINE_CONTINUE);
+		zio_interrupt(zio);
+		return;
 	}
 
 	error = __vdev_disk_physio(vd->vd_bdev, zio, zio->io_data,
 	    zio->io_size, zio->io_offset, flags);
 	if (error) {
 		zio->io_error = error;
-		return (ZIO_PIPELINE_CONTINUE);
+		zio_interrupt(zio);
+		return;
 	}
-
-	return (ZIO_PIPELINE_STOP);
 }
 
 static void
diff --git a/module/zfs/vdev_file.c b/module/zfs/vdev_file.c
index 7f43ad800..3c3a13993 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) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -172,7 +172,7 @@ vdev_file_io_fsync(void *arg)
 	zio_interrupt(zio);
 }
 
-static int
+static void
 vdev_file_io_start(zio_t *zio)
 {
 	vdev_t *vd = zio->io_vd;
@@ -182,7 +182,8 @@ vdev_file_io_start(zio_t *zio)
 		/* XXPOLICY */
 		if (!vdev_readable(vd)) {
 			zio->io_error = SET_ERROR(ENXIO);
-			return (ZIO_PIPELINE_CONTINUE);
+			zio_interrupt(zio);
+			return;
 		}
 
 		switch (zio->io_cmd) {
@@ -201,7 +202,7 @@ vdev_file_io_start(zio_t *zio)
 			if (spl_fstrans_check()) {
 				VERIFY3U(taskq_dispatch(vdev_file_taskq,
 				    vdev_file_io_fsync, zio, TQ_SLEEP), !=, 0);
-				return (ZIO_PIPELINE_STOP);
+				return;
 			}
 
 			zio->io_error = VOP_FSYNC(vf->vf_vnode, FSYNC | FDSYNC,
@@ -211,13 +212,12 @@ vdev_file_io_start(zio_t *zio)
 			zio->io_error = SET_ERROR(ENOTSUP);
 		}
 
-		return (ZIO_PIPELINE_CONTINUE);
+		zio_execute(zio);
+		return;
 	}
 
 	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 77c3d8d38..6b699e883 100644
--- a/module/zfs/vdev_mirror.c
+++ b/module/zfs/vdev_mirror.c
@@ -24,7 +24,7 @@
  */
 
 /*
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -327,7 +327,7 @@ vdev_mirror_child_select(zio_t *zio)
 	return (-1);
 }
 
-static int
+static void
 vdev_mirror_io_start(zio_t *zio)
 {
 	mirror_map_t *mm;
@@ -352,7 +352,8 @@ vdev_mirror_io_start(zio_t *zio)
 				    zio->io_type, zio->io_priority, 0,
 				    vdev_mirror_scrub_done, mc));
 			}
-			return (ZIO_PIPELINE_CONTINUE);
+			zio_execute(zio);
+			return;
 		}
 		/*
 		 * For normal reads just pick one child.
@@ -378,7 +379,7 @@ vdev_mirror_io_start(zio_t *zio)
 		c++;
 	}
 
-	return (ZIO_PIPELINE_CONTINUE);
+	zio_execute(zio);
 }
 
 static int
diff --git a/module/zfs/vdev_missing.c b/module/zfs/vdev_missing.c
index b9eb99d18..228757334 100644
--- a/module/zfs/vdev_missing.c
+++ b/module/zfs/vdev_missing.c
@@ -24,7 +24,7 @@
  */
 
 /*
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
  */
 
 /*
@@ -66,11 +66,11 @@ vdev_missing_close(vdev_t *vd)
 }
 
 /* ARGSUSED */
-static int
+static void
 vdev_missing_io_start(zio_t *zio)
 {
 	zio->io_error = SET_ERROR(ENOTSUP);
-	return (ZIO_PIPELINE_CONTINUE);
+	zio_execute(zio);
 }
 
 /* ARGSUSED */
diff --git a/module/zfs/vdev_raidz.c b/module/zfs/vdev_raidz.c
index 493b332c4..b9479092c 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) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -1567,7 +1567,7 @@ vdev_raidz_child_done(zio_t *zio)
  *      vdevs have had errors, then create zio read operations to the parity
  *      columns' VDevs as well.
  */
-static int
+static void
 vdev_raidz_io_start(zio_t *zio)
 {
 	vdev_t *vd = zio->io_vd;
@@ -1611,7 +1611,8 @@ vdev_raidz_io_start(zio_t *zio)
 			    ZIO_FLAG_NODATA | ZIO_FLAG_OPTIONAL, NULL, NULL));
 		}
 
-		return (ZIO_PIPELINE_CONTINUE);
+		zio_execute(zio);
+		return;
 	}
 
 	ASSERT(zio->io_type == ZIO_TYPE_READ);
@@ -1651,7 +1652,7 @@ vdev_raidz_io_start(zio_t *zio)
 		}
 	}
 
-	return (ZIO_PIPELINE_CONTINUE);
+	zio_execute(zio);
 }
 
 
diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 066f04f18..032341378 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -59,6 +59,9 @@ 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.
@@ -2526,6 +2529,18 @@ 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)
 {
@@ -2543,7 +2558,8 @@ zio_vdev_io_start(zio_t *zio)
 		/*
 		 * The mirror_ops handle multiple DVAs in a single BP.
 		 */
-		return (vdev_mirror_ops.vdev_op_io_start(zio));
+		vdev_mirror_ops.vdev_op_io_start(zio);
+		return (ZIO_PIPELINE_STOP);
 	}
 
 	/*
@@ -2551,7 +2567,7 @@ 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.
@@ -2637,7 +2653,8 @@ zio_vdev_io_start(zio_t *zio)
 		}
 	}
 
-	return (vd->vdev_ops->vdev_op_io_start(zio));
+	vd->vdev_ops->vdev_op_io_start(zio);
+	return (ZIO_PIPELINE_STOP);
 }
 
 static int