From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Sat, 11 Oct 2014 01:12:47 +0000 (-0700)
Subject: Handle NULL mirror child vdev
X-Git-Tag: zfs-0.6.4~128
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=33074f2254db76f7237e5a29877558ef920ae325;p=zfs

Handle NULL mirror child vdev

When selecting a mirror child it's possible that map allocated by
vdev_mirror_map_allc() contains a NULL for the child vdev.  In
this case the child should be skipped and the read issues to
another member of the mirror.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #1744
---

diff --git a/module/zfs/vdev_mirror.c b/module/zfs/vdev_mirror.c
index 99b35f085..17417a0fa 100644
--- a/module/zfs/vdev_mirror.c
+++ b/module/zfs/vdev_mirror.c
@@ -300,7 +300,7 @@ vdev_mirror_child_select(zio_t *zio)
 		mc = &mm->mm_child[c];
 		if (mc->mc_tried || mc->mc_skipped)
 			continue;
-		if (!vdev_readable(mc->mc_vd)) {
+		if (mc->mc_vd == NULL || !vdev_readable(mc->mc_vd)) {
 			mc->mc_error = SET_ERROR(ENXIO);
 			mc->mc_tried = 1;	/* don't even try */
 			mc->mc_skipped = 1;