From d9cc6e231897a9ab1a94e6cfe12d71bfec0b7a81 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Wed, 27 Apr 2011 10:25:28 +0200 Subject: [PATCH] drbd: fix various disconnecting races If an admin requests disconnect at a time when the state handling already disconnects/reconnects, there have been some races. Make sure to always really stop the network threads before returning success for disconnect. Do not pretend successfull forced disconnect, if the state handling returned an error. Return success from drbd_adm_down() only after all threads are finished. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_nl.c | 21 ++++++++++++--------- drivers/block/drbd/drbd_receiver.c | 2 +- drivers/block/drbd/drbd_state.c | 20 +++++++++++++------- 3 files changed, 26 insertions(+), 17 deletions(-) diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 1a8fb7a0db59..a16089ce0a56 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -2075,10 +2075,9 @@ static enum drbd_state_rv conn_try_disconnect(struct drbd_tconn *tconn, bool for enum drbd_state_rv rv; if (force) { spin_lock_irq(&tconn->req_lock); - if (tconn->cstate >= C_WF_CONNECTION) - _conn_request_state(tconn, NS(conn, C_DISCONNECTING), CS_HARD); + rv = _conn_request_state(tconn, NS(conn, C_DISCONNECTING), CS_HARD); spin_unlock_irq(&tconn->req_lock); - return SS_SUCCESS; + return rv; } rv = conn_request_state(tconn, NS(conn, C_DISCONNECTING), 0); @@ -2137,10 +2136,12 @@ int drbd_adm_disconnect(struct sk_buff *skb, struct genl_info *info) if (rv < SS_SUCCESS) goto fail; + /* No one else can reconfigure the network while I am here. + * The state handling only uses drbd_thread_stop_nowait(), + * we want to really wait here until the receiver is no more. */ + drbd_thread_stop(&tconn->receiver); if (wait_event_interruptible(tconn->ping_wait, - tconn->cstate != C_DISCONNECTING)) { - /* Do not test for mdev->state.conn == C_STANDALONE, since - someone else might connect us in the mean time! */ + tconn->cstate == C_STANDALONE)) { retcode = ERR_INTR; goto fail; } @@ -3043,6 +3044,10 @@ int drbd_adm_down(struct sk_buff *skb, struct genl_info *info) goto out_unlock; } + /* Make sure the network threads have actually stopped, + * state handling only does drbd_thread_stop_nowait(). */ + drbd_thread_stop(&adm_ctx.tconn->receiver); + /* detach */ idr_for_each_entry(&adm_ctx.tconn->volumes, mdev, i) { rv = adm_detach(mdev); @@ -3066,11 +3071,9 @@ int drbd_adm_down(struct sk_buff *skb, struct genl_info *info) } } - /* stop all threads */ - conn_reconfig_done(adm_ctx.tconn); - /* delete connection */ if (conn_lowest_minor(adm_ctx.tconn) < 0) { + drbd_thread_stop(&adm_ctx.tconn->worker); list_del(&adm_ctx.tconn->all_tconn); kref_put(&adm_ctx.tconn->kref, &conn_destroy); diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 4665ad79b4ae..6da7aebde8df 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -4226,7 +4226,7 @@ static void drbd_disconnect(struct drbd_tconn *tconn) synchronize_rcu(); kfree(old_conf); - conn_request_state(tconn, NS(conn, C_STANDALONE), CS_VERBOSE); + conn_request_state(tconn, NS(conn, C_STANDALONE), CS_VERBOSE | CS_HARD); } } diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c index 05628b45cf03..8b0f31b6808a 100644 --- a/drivers/block/drbd/drbd_state.c +++ b/drivers/block/drbd/drbd_state.c @@ -604,21 +604,27 @@ is_valid_soft_transition(union drbd_state os, union drbd_state ns) static enum drbd_state_rv is_valid_conn_transition(enum drbd_conns oc, enum drbd_conns nc) { - enum drbd_state_rv rv = SS_SUCCESS; + /* no change -> nothing to do, at least for the connection part */ + if (oc == nc) + return SS_NOTHING_TO_DO; - /* Disallow Network errors to configure a device's network part */ - if ((nc >= C_TIMEOUT && nc <= C_TEAR_DOWN) && oc <= C_DISCONNECTING) - rv = SS_NEED_CONNECTION; + /* disconnect of an unconfigured connection does not make sense */ + if (oc == C_STANDALONE && nc == C_DISCONNECTING) + return SS_ALREADY_STANDALONE; + + /* from C_STANDALONE, we start with C_UNCONNECTED */ + if (oc == C_STANDALONE && nc != C_UNCONNECTED) + return SS_NEED_CONNECTION; /* After a network error only C_UNCONNECTED or C_DISCONNECTING may follow. */ if (oc >= C_TIMEOUT && oc <= C_TEAR_DOWN && nc != C_UNCONNECTED && nc != C_DISCONNECTING) - rv = SS_IN_TRANSIENT_STATE; + return SS_IN_TRANSIENT_STATE; /* After C_DISCONNECTING only C_STANDALONE may follow */ if (oc == C_DISCONNECTING && nc != C_STANDALONE) - rv = SS_IN_TRANSIENT_STATE; + return SS_IN_TRANSIENT_STATE; - return rv; + return SS_SUCCESS; } -- GitLab