From e636db5b956950b8b9bfbeb766a637f84bae1e3b Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Fri, 21 Jan 2011 17:10:37 +0100 Subject: drbd: fix potential imbalance of ap_in_flight When we receive a barrier ack, we walk the ring list of drbd requests in the transfer log of the respective epoch, do some housekeeping, and free those objects. We tried to keep epochs of mirrored and unmirrored drbd requests separate, and assert that no local-only requests are present in a barrier_acked epoch. It turns out that this has quite a number of corner cases and would add bloated code without functional benefit. We now revert the (insufficient) commits drbd: Fixed an issue with AHEAD -> SYNC_SOURCE transitions drbd: Ensure that an epoch contains only requests of one kind and instead fix the processing of barrier acks to cope with a mix of local-only and mirrored requests. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_main.c | 25 ------------------------- drivers/block/drbd/drbd_req.c | 9 +++++---- 2 files changed, 5 insertions(+), 29 deletions(-) diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index c3760f33d52c..9043772de400 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -337,23 +337,6 @@ bail: } -/* In C_AHEAD mode only out_of_sync packets are sent for requests. Detach - * those requests from the newsest barrier when changing to an other cstate. - * - * That headless list vanishes when the last request finished its write or - * send out_of_sync packet. */ -static void tl_forget(struct drbd_conf *mdev) -{ - struct drbd_tl_epoch *b; - - if (test_bit(CREATE_BARRIER, &mdev->flags)) - return; - - b = mdev->newest_tle; - list_del(&b->requests); - _tl_add_barrier(mdev, b); -} - /** * _tl_restart() - Walks the transfer log, and applies an action to all requests * @mdev: DRBD device. @@ -1265,14 +1248,6 @@ __drbd_set_state(struct drbd_conf *mdev, union drbd_state ns, if (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED) drbd_resume_al(mdev); - /* Start a new epoch in case we start to mirror write requests */ - if (!drbd_should_do_remote(os) && drbd_should_do_remote(ns)) - tl_forget(mdev); - - /* Do not add local-only requests to an epoch with mirrored requests */ - if (drbd_should_do_remote(os) && !drbd_should_do_remote(ns)) - set_bit(CREATE_BARRIER, &mdev->flags); - ascw = kmalloc(sizeof(*ascw), GFP_ATOMIC); if (ascw) { ascw->os = os; diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index 336937a14d3f..c28be4e5e57c 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -712,10 +712,11 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what, dev_err(DEV, "FIXME (barrier_acked but pending)\n"); list_move(&req->tl_requests, &mdev->out_of_sequence_requests); } - D_ASSERT(req->rq_state & RQ_NET_SENT); - req->rq_state |= RQ_NET_DONE; - if (mdev->net_conf->wire_protocol == DRBD_PROT_A) - atomic_sub(req->size>>9, &mdev->ap_in_flight); + if ((req->rq_state & RQ_NET_MASK) != 0) { + req->rq_state |= RQ_NET_DONE; + if (mdev->net_conf->wire_protocol == DRBD_PROT_A) + atomic_sub(req->size>>9, &mdev->ap_in_flight); + } _req_may_be_done(req, m); /* Allowed while state.susp */ break; -- cgit v1.2.2