md/multipath: add rcu protection to rdev access in multipath_status.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
This commit is contained in:
NeilBrown 2016-06-02 16:19:52 +10:00 committed by Shaohua Li
parent 5fd133511d
commit 40cf2123c5

View File

@ -141,17 +141,19 @@ static void multipath_make_request(struct mddev *mddev, struct bio * bio)
return;
}
static void multipath_status (struct seq_file *seq, struct mddev *mddev)
static void multipath_status(struct seq_file *seq, struct mddev *mddev)
{
struct mpconf *conf = mddev->private;
int i;
seq_printf (seq, " [%d/%d] [", conf->raid_disks,
conf->raid_disks - mddev->degraded);
for (i = 0; i < conf->raid_disks; i++)
seq_printf (seq, "%s",
conf->multipaths[i].rdev &&
test_bit(In_sync, &conf->multipaths[i].rdev->flags) ? "U" : "_");
rcu_read_lock();
for (i = 0; i < conf->raid_disks; i++) {
struct md_rdev *rdev = rcu_dereference(conf->multipaths[i].rdev);
seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
}
rcu_read_unlock();
seq_printf (seq, "]");
}