From: Lars Ellenberg <lars.ellenberg@linbit.com>
Date: Mon, 20 Aug 2012 12:54:48 +0000 (+0200)
Subject: drbd: temporarily suspend io in drbd_adm_disk_opts
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0ee98e2eb0c85f27b6f24a15d59fb54f99a93840;p=linux-beck.git

drbd: temporarily suspend io in drbd_adm_disk_opts

drbd_adm_disk_opts() does
	wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
	drbd_al_shrink(mdev);

If the device is very busy, this can take a very long time to succeed.
Fix this by temporarily suspending IO,
then quickly change the settings, and resume.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index d31a0261e83e..363034a77e88 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1210,11 +1210,13 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 		}
 	}
 
+	drbd_suspend_io(mdev);
 	wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
 	drbd_al_shrink(mdev);
 	err = drbd_check_al_size(mdev, new_disk_conf);
 	lc_unlock(mdev->act_log);
 	wake_up(&mdev->al_wait);
+	drbd_resume_io(mdev);
 
 	if (err) {
 		retcode = ERR_NOMEM;