From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19B1DC433DF for ; Tue, 13 Oct 2020 12:02:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC855206D9 for ; Tue, 13 Oct 2020 12:02:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602590553; bh=vXWoXdjL8NGrqE4RIVrf8WnusQgXUFFgor0O6o395Pk=; h=From:To:Cc:Subject:Date:List-ID:From; b=z0LLEqD9Cgp0DEPd8FcNVA3Ks7GhCeT9InEemiQ5bwV1fkE8SBCZg+CRGuo5T6XbT 8J0tsgv3GrRgzhEtGHpy6UUVRb6WiGLdmC1YBLSi2WrACWuFs+d80cPLLz8nLAIMBC XqhFJl+DB86jm1JaMXlD+ZVI44HT5OmPqkfjgC3U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727785AbgJMMCc (ORCPT ); Tue, 13 Oct 2020 08:02:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:37708 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727460AbgJMMCZ (ORCPT ); Tue, 13 Oct 2020 08:02:25 -0400 Received: from tleilax.com (68-20-15-154.lightspeed.rlghnc.sbcglobal.net [68.20.15.154]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BB25E206D9; Tue, 13 Oct 2020 12:02:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602590544; bh=vXWoXdjL8NGrqE4RIVrf8WnusQgXUFFgor0O6o395Pk=; h=From:To:Cc:Subject:Date:From; b=Dr+B5p9eRtdFD7QgSPTqWvb2nX372hNa5+EH1xPgs3oCImgnAjrCERF8cGe6vmMiF 6OxS2qhs2duiBrUHw/drgzQ2yOKaERZMQPLhks8lf4u4GOllWiU6uo5/+UWZ6pU60D f4Y1gKne+QEKUw0MRXpi8mGm+qGZGisBNJLs1NGE= From: Jeff Layton To: ceph-devel@vger.kernel.org Cc: idryomov@gmail.com, ukernel@gmail.com, pdonnell@redhat.com, xiubli@redhat.com Subject: [PATCH v3] ceph: check session state after bumping session->s_seq Date: Tue, 13 Oct 2020 08:02:21 -0400 Message-Id: <20201013120221.322461-1-jlayton@kernel.org> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org Some messages sent by the MDS entail a session sequence number increment, and the MDS will drop certain types of requests on the floor when the sequence numbers don't match. In particular, a REQUEST_CLOSE message can cross with one of the sequence morphing messages from the MDS which can cause the client to stall, waiting for a response that will never come. Originally, this meant an up to 5s delay before the recurring workqueue job kicked in and resent the request, but a recent change made it so that the client would never resend, causing a 60s stall unmounting and sometimes a blockisting event. Add a new helper for incrementing the session sequence and then testing to see whether a REQUEST_CLOSE needs to be resent, and move the handling of CEPH_MDS_SESSION_CLOSING into that function. Change all of the bare sequence counter increments to use the new helper. Reorganize check_session_state with a switch statement. It should no longer be called when the session is CLOSING, so throw a warning if it ever is (but still handle that case sanely). URL: https://tracker.ceph.com/issues/47563 Fixes: fa9967734227 ("ceph: fix potential mdsc use-after-free crash") Reported-by: Patrick Donnelly Signed-off-by: Jeff Layton --- fs/ceph/caps.c | 2 +- fs/ceph/mds_client.c | 51 ++++++++++++++++++++++++++++++-------------- fs/ceph/mds_client.h | 1 + fs/ceph/quota.c | 2 +- fs/ceph/snap.c | 2 +- 5 files changed, 39 insertions(+), 19 deletions(-) v3: reorganize check_session_state with switch statement. Don't attempt to reconnect in there, but do throw a warning if it's called while the session is CLOSING. diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index c00abd7eefc1..ba0e4f44862c 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -4071,7 +4071,7 @@ void ceph_handle_caps(struct ceph_mds_session *session, vino.snap, inode); mutex_lock(&session->s_mutex); - session->s_seq++; + inc_session_sequence(session); dout(" mds%d seq %lld cap seq %u\n", session->s_mds, session->s_seq, (unsigned)seq); diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 0190555b1f9e..00c0dc33f92e 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -4237,7 +4237,7 @@ static void handle_lease(struct ceph_mds_client *mdsc, dname.len, dname.name); mutex_lock(&session->s_mutex); - session->s_seq++; + inc_session_sequence(session); if (!inode) { dout("handle_lease no inode %llx\n", vino.ino); @@ -4386,28 +4386,47 @@ static void maybe_recover_session(struct ceph_mds_client *mdsc) bool check_session_state(struct ceph_mds_session *s) { - if (s->s_state == CEPH_MDS_SESSION_CLOSING) { - dout("resending session close request for mds%d\n", - s->s_mds); - request_close_session(s); - return false; - } - if (s->s_ttl && time_after(jiffies, s->s_ttl)) { - if (s->s_state == CEPH_MDS_SESSION_OPEN) { + + switch (s->s_state) { + case CEPH_MDS_SESSION_OPEN: + if (s->s_ttl && time_after(jiffies, s->s_ttl)) { s->s_state = CEPH_MDS_SESSION_HUNG; pr_info("mds%d hung\n", s->s_mds); } - } - if (s->s_state == CEPH_MDS_SESSION_NEW || - s->s_state == CEPH_MDS_SESSION_RESTARTING || - s->s_state == CEPH_MDS_SESSION_CLOSED || - s->s_state == CEPH_MDS_SESSION_REJECTED) - /* this mds is failed or recovering, just wait */ + break; + case CEPH_MDS_SESSION_CLOSING: + /* Should never reach this when we're unmounting */ + WARN_ON_ONCE(true); + fallthrough; + case CEPH_MDS_SESSION_NEW: + case CEPH_MDS_SESSION_RESTARTING: + case CEPH_MDS_SESSION_CLOSED: + case CEPH_MDS_SESSION_REJECTED: return false; - + } return true; } +/* + * If the sequence is incremented while we're waiting on a REQUEST_CLOSE reply, + * then we need to retransmit that request. + */ +void inc_session_sequence(struct ceph_mds_session *s) +{ + lockdep_assert_held(&s->s_mutex); + + s->s_seq++; + + if (s->s_state == CEPH_MDS_SESSION_CLOSING) { + int ret; + + dout("resending session close request for mds%d\n", s->s_mds); + ret = request_close_session(s); + if (ret < 0) + pr_err("ceph: Unable to close session to mds %d: %d\n", s->s_mds, ret); + } +} + /* * delayed work -- periodically trim expired leases, renew caps with mds */ diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h index cbf8af437140..f5adbebcb38e 100644 --- a/fs/ceph/mds_client.h +++ b/fs/ceph/mds_client.h @@ -480,6 +480,7 @@ struct ceph_mds_client { extern const char *ceph_mds_op_name(int op); extern bool check_session_state(struct ceph_mds_session *s); +void inc_session_sequence(struct ceph_mds_session *s); extern struct ceph_mds_session * __ceph_lookup_mds_session(struct ceph_mds_client *, int mds); diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c index 83cb4f26b689..9b785f11e95a 100644 --- a/fs/ceph/quota.c +++ b/fs/ceph/quota.c @@ -53,7 +53,7 @@ void ceph_handle_quota(struct ceph_mds_client *mdsc, /* increment msg sequence number */ mutex_lock(&session->s_mutex); - session->s_seq++; + inc_session_sequence(session); mutex_unlock(&session->s_mutex); /* lookup inode */ diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index 0da39c16dab4..b611f829cb61 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -873,7 +873,7 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc, ceph_snap_op_name(op), split, trace_len); mutex_lock(&session->s_mutex); - session->s_seq++; + inc_session_sequence(session); mutex_unlock(&session->s_mutex); down_write(&mdsc->snap_rwsem); -- 2.26.2