From: Philipp Reisner Date: Wed, 1 Sep 2010 13:47:15 +0000 (+0200) Subject: drbd: Removed a race that could cause unexpected execution of w_make_resync_request() X-Git-Tag: upstream/snapshot3+hdmi~12709^2~33 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=63106d3c6c769b6219bd04edde513b12abae3f61;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git drbd: Removed a race that could cause unexpected execution of w_make_resync_request() The actual race happened int the drbd_start_resync() function. Where drbd_resync_finished() -> __drbd_set_state() set STOP_SYNC_TIMER and armed the timer. If the timer fired before execution reaches the mod_timer statement at the end of drbd_start_resync() the latter would cause an unexpected call to w_make_resync_request(). Removed the STOP_SYNC_TIMER bit, and base it on the connection state. The STOP_SYNC_TIMER bit probably originates probably the time before the state engine. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index bb3a488..d5e38de8 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -827,7 +827,6 @@ enum { SIGNAL_ASENDER, /* whether asender wants to be interrupted */ SEND_PING, /* whether asender should send a ping asap */ - STOP_SYNC_TIMER, /* tell timer to cancel itself */ UNPLUG_QUEUED, /* only relevant with kernel 2.4 */ UNPLUG_REMOTE, /* sending a "UnplugRemote" could help */ MD_DIRTY, /* current uuids and flags not yet on disk */ diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 73c905d..5dd071e 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -1052,12 +1052,6 @@ int __drbd_set_state(struct drbd_conf *mdev, wake_up(&mdev->misc_wait); wake_up(&mdev->state_wait); - /* post-state-change actions */ - if (os.conn >= C_SYNC_SOURCE && ns.conn <= C_CONNECTED) { - set_bit(STOP_SYNC_TIMER, &mdev->flags); - mod_timer(&mdev->resync_timer, jiffies); - } - /* aborted verify run. log the last position */ if ((os.conn == C_VERIFY_S || os.conn == C_VERIFY_T) && ns.conn < C_CONNECTED) { @@ -1072,22 +1066,14 @@ int __drbd_set_state(struct drbd_conf *mdev, dev_info(DEV, "Syncer continues.\n"); mdev->rs_paused += (long)jiffies -(long)mdev->rs_mark_time[mdev->rs_last_mark]; - if (ns.conn == C_SYNC_TARGET) { - if (!test_and_clear_bit(STOP_SYNC_TIMER, &mdev->flags)) - mod_timer(&mdev->resync_timer, jiffies); - /* This if (!test_bit) is only needed for the case - that a device that has ceased to used its timer, - i.e. it is already in drbd_resync_finished() gets - paused and resumed. */ - } + if (ns.conn == C_SYNC_TARGET) + mod_timer(&mdev->resync_timer, jiffies); } if ((os.conn == C_SYNC_TARGET || os.conn == C_SYNC_SOURCE) && (ns.conn == C_PAUSED_SYNC_T || ns.conn == C_PAUSED_SYNC_S)) { dev_info(DEV, "Resync suspended\n"); mdev->rs_mark_time[mdev->rs_last_mark] = jiffies; - if (ns.conn == C_PAUSED_SYNC_T) - set_bit(STOP_SYNC_TIMER, &mdev->flags); } if (os.conn == C_CONNECTED && diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 4249117..885471d 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -3803,7 +3803,6 @@ static void drbd_disconnect(struct drbd_conf *mdev) /* make sure syncer is stopped and w_resume_next_sg queued */ del_timer_sync(&mdev->resync_timer); - set_bit(STOP_SYNC_TIMER, &mdev->flags); resync_timer_fn((unsigned long)mdev); /* wait for all w_e_end_data_req, w_e_end_rsdata_req, w_send_barrier, diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c index 8be9832..0e5bf8c 100644 --- a/drivers/block/drbd/drbd_worker.c +++ b/drivers/block/drbd/drbd_worker.c @@ -395,25 +395,22 @@ defer: void resync_timer_fn(unsigned long data) { - unsigned long flags; struct drbd_conf *mdev = (struct drbd_conf *) data; int queue; - spin_lock_irqsave(&mdev->req_lock, flags); - - if (likely(!test_and_clear_bit(STOP_SYNC_TIMER, &mdev->flags))) { - queue = 1; - if (mdev->state.conn == C_VERIFY_S) - mdev->resync_work.cb = w_make_ov_request; - else - mdev->resync_work.cb = w_make_resync_request; - } else { + queue = 1; + switch (mdev->state.conn) { + case C_VERIFY_S: + mdev->resync_work.cb = w_make_ov_request; + break; + case C_SYNC_TARGET: + mdev->resync_work.cb = w_make_resync_request; + break; + default: queue = 0; mdev->resync_work.cb = w_resync_inactive; } - spin_unlock_irqrestore(&mdev->req_lock, flags); - /* harmless race: list_empty outside data.work.q_lock */ if (list_empty(&mdev->resync_work.list) && queue) drbd_queue_work(&mdev->data.work, &mdev->resync_work);