From 9a0d9d0389ef769e4b01abf50fcc11407706270b Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Mon, 2 May 2011 11:51:31 +0200 Subject: 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. manually picked commit 564040f from the drbd 8.4 branch. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_int.h | 4 ++++ drivers/block/drbd/drbd_nl.c | 14 +++++++++++--- 2 files changed, 15 insertions(+), 3 deletions(-) (limited to 'drivers') diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index 8aa1039..a74d3ee 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -2157,6 +2157,10 @@ static inline int get_net_conf(struct drbd_conf *mdev) static inline void put_ldev(struct drbd_conf *mdev) { int i = atomic_dec_return(&mdev->local_cnt); + + /* This may be called from some endio handler, + * so we must not sleep here. */ + __release(local); D_ASSERT(i >= 0); if (i == 0) { diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 7c64ec04..1356963 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -1334,11 +1334,19 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp static int drbd_nl_detach(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp, struct drbd_nl_cfg_reply *reply) { + enum drbd_ret_code retcode; + int ret; drbd_suspend_io(mdev); /* so no-one is stuck in drbd_al_begin_io */ - reply->ret_code = drbd_request_state(mdev, NS(disk, D_DISKLESS)); - if (mdev->state.disk == D_DISKLESS) - wait_event(mdev->misc_wait, !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 (retcode == SS_IS_DISKLESS) + retcode = SS_NOTHING_TO_DO; + if (ret) + retcode = ERR_INTR; + reply->ret_code = retcode; return 0; } -- cgit v1.1