From 009ba89db5ae836949009f97a00abb96feba69f4 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Mon, 2 May 2011 11:51:31 +0200 Subject: [PATCH] drbd: fix schedule in atomic An administrative detach used to request a state change directly to D_DISKLESS, first suspending IO to avoid the last put_ldev() occuring from an endio handler, potentially in irq context. This is not enough on the receiving side (typically secondary), we may miss some peer_req on the way to local disk, which then may do the last put_ldev() from their drbd_peer_request_endio(). This patch makes the detach always go through the intermediate D_FAILED state. We may consider to rename it D_DETACHING. Alternative approach would be to create yet an other work item to be scheduled on the worker, do the destructor work from there, and get the timing right. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_nl.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 25468e2..7320ac0 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -1670,12 +1670,17 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) static int adm_detach(struct drbd_conf *mdev) { enum drbd_state_rv retcode; + int ret; drbd_suspend_io(mdev); /* so no-one is stuck in drbd_al_begin_io */ - retcode = drbd_request_state(mdev, NS(disk, D_DISKLESS)); - wait_event(mdev->misc_wait, - mdev->state.disk != D_DISKLESS || - !atomic_read(&mdev->local_cnt)); + retcode = drbd_request_state(mdev, NS(disk, D_FAILED)); + /* D_FAILED will transition to DISKLESS. */ + ret = wait_event_interruptible(mdev->misc_wait, + mdev->state.disk != D_FAILED); drbd_resume_io(mdev); + if ((int)retcode == (int)SS_IS_DISKLESS) + retcode = SS_NOTHING_TO_DO; + if (ret) + retcode = ERR_INTR; return retcode; } -- 2.7.4