[PATCH 4.4 013/137] libnvdimm, pfn: fix uuid validation

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Williams <dan.j.williams@xxxxxxxxx>

commit e5670563f588ed1c0603819350c0f02cec23f5c5 upstream.

If we detect a namespace has a stale info block in the init path, we
should overwrite with the latest configuration.  In fact, we already
return -ENODEV when the parent uuid is invalid, the same should be done
for the 'self' uuid.  Otherwise we can get into a condition where
userspace is unable to reconfigure the pfn-device without directly /
manually invalidating the info block.

Reported-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/nvdimm/pfn_devs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -275,7 +275,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pf
 	} else {
 		/* from init we validate */
 		if (memcmp(nd_pfn->uuid, pfn_sb->uuid, 16) != 0)
-			return -EINVAL;
+			return -ENODEV;
 	}
 
 	/*