From 4d89b7b4e4726893453d0fb4ddbb5b3e16353994 Mon Sep 17 00:00:00 2001
From: Milan Broz <mbroz@redhat.com>
Date: Mon, 22 Jun 2009 10:12:11 +0100
Subject: [PATCH] dm: sysfs skip output when device is being destroyed

Do not process sysfs attributes when device is being destroyed.

Otherwise code can cause
  BUG_ON(test_bit(DMF_FREEING, &md->flags));
in dm_put() call.

Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
---
 drivers/md/dm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 48db308fae67..f1db689667ea 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1777,6 +1777,10 @@ struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
 	if (&md->kobj != kobj)
 		return NULL;
 
+	if (test_bit(DMF_FREEING, &md->flags) ||
+	    test_bit(DMF_DELETING, &md->flags))
+		return NULL;
+
 	dm_get(md);
 	return md;
 }
-- 
2.20.1