md: prevent duplicates in bind_rdev_to_array

Found when trying to reassemble an active externally managed array.  Without
this check we hit the more noisy "sysfs duplicate" warning in the later call
to kobject_add.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 75a3f483522d..bec00b201a73 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1370,6 +1370,11 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
                 MD_BUG();
                 return -EINVAL;
         }
+
+        /* prevent duplicates */
+        if (find_rdev(mddev, rdev->bdev->bd_dev))
+                return -EEXIST;
+
         /* make sure rdev->size exceeds mddev->size */
         if (rdev->size && (mddev->size == 0 || rdev->size < mddev->size)) {
                 if (mddev->pers) {