[PATCH 3.10 028/103] md: avoid possible spinning md thread at shutdown.

Greg Kroah-Hartman
2014-06-04T23:42:43Z

From: NeilBrown <neilb@suse.de>

commit 0f62fb220aa4ebabe8547d3a9ce4a16d3c045f21 upstream.

If an md array with externally managed metadata (e.g. DDF or IMSM)
is in use, then we should not set safemode==2 at shutdown because:

1/ this is ineffective: user-space need to be involved in any 'safemode' handling,
2/ The safemode management code doesn't cope with safemode==2 on external metadata
and md_check_recover enters an infinite loop.

Even at shutdown, an infinite-looping process can be problematic, so this
could cause shutdown to hang.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/md.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8481,7 +8481,8 @@ static int md_notify_reboot(struct notif
if (mddev_trylock(mddev)) {
if (mddev->pers)
__md_stop_writes(mddev);
- mddev->safemode = 2;
+ if (mddev->persistent)
+ mddev->safemode = 2;
mddev_unlock(mddev);
}
need_delay = 1;