From 81f448629aa25051c47b4d5b81702da8cbe922c3 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Mon, 26 Mar 2012 15:09:44 +0200 Subject: drbd: Fix a potential race that could case data inconsistency When we have a write request and a state change C_WF_BITMAP_S -> C_SYNC_SOURCE at the same time, and it happens that the line remote = remote && drbd_should_do_remote(s); stills sees C_WF_BITMAP_S, and send_oos = rw == WRITE && drbd_should_send_oos(s); already sees C_SYNC_SOURCE both are 0. This causes the write to not be mirrored, but marked as out-of-sync on the Sync_Source node. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index 3e4dc07..c3f99bd 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -822,6 +822,7 @@ int __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long s int local, remote, send_oos = 0; int err; int ret = 0; + union drbd_dev_state s; /* allocate outside of all locks; */ req = drbd_req_new(mdev, bio); @@ -884,8 +885,9 @@ int __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long s drbd_al_begin_io(mdev, &req->i); } - remote = remote && drbd_should_do_remote(mdev->state); - send_oos = rw == WRITE && drbd_should_send_out_of_sync(mdev->state); + s = mdev->state; + remote = remote && drbd_should_do_remote(s); + send_oos = rw == WRITE && drbd_should_send_out_of_sync(s); D_ASSERT(!(remote && send_oos)); if (!(local || remote) && !drbd_suspended(mdev)) { -- cgit v0.10.2