From patchwork Thu Oct 19 15:59:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Coddington X-Patchwork-Id: 13429479 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4979DCDB465 for ; Thu, 19 Oct 2023 16:00:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346475AbjJSQAU (ORCPT ); Thu, 19 Oct 2023 12:00:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345737AbjJSQAT (ORCPT ); Thu, 19 Oct 2023 12:00:19 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07388112 for ; Thu, 19 Oct 2023 08:59:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1697731171; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=n5YIYGgOGXO5a1I/NLpBl4Lpc+zw4UO/MrgimT+sYFw=; b=DeYEdOy3enn2rH9IpNKzU4B0AS76fYuAMl1osXW8HynW9UnyCleVFVOgHJ2nANbZNdCB2K f1KFoxM9sFnpvujCBddovzU6MndDzOi3Gi8D8wIuoJPxfLUtlsKesoKIG0SK6SFbRdUzea GyIPekJo49i3Rlxb8/kQItg+xsv8r3w= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-536-UYGzGbVMPQ6uQLs_i33Yww-1; Thu, 19 Oct 2023 11:59:23 -0400 X-MC-Unique: UYGzGbVMPQ6uQLs_i33Yww-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2B015891767; Thu, 19 Oct 2023 15:59:23 +0000 (UTC) Received: from bcodding.csb.redhat.com (unknown [10.22.48.7]) by smtp.corp.redhat.com (Postfix) with ESMTP id BCFBFC15BB8; Thu, 19 Oct 2023 15:59:22 +0000 (UTC) From: Benjamin Coddington To: trond.myklebust@hammerspace.com, anna@kernel.org Cc: linux-nfs@vger.kernel.org Subject: [RESEND PATCH v2] NFSv4: fairly test all delegations on a SEQ4_ revocation Date: Thu, 19 Oct 2023 11:59:22 -0400 Message-ID: <20231019155922.6549-1-bcodding@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org When the client is required to use TEST_STATEID to discover which delegation(s) have been revoked, it may continually test delegations at the head of the list if the server continues to be unsatisfied and send SEQ4_STATUS_RECALLABLE_STATE_REVOKED. For a large number of delegations this behavior is prone to live-lock because the client may never be able to test and free revoked state at the end of the list since the SEQ4_STATUS_RECALLABLE_STATE_REVOKED will cause us to flag delegations at the head of the list to be tested. This problem is further exacerbated by the state manager's willingness to be scheduled out on a busy system while testing the list of delegations. Keep a generation counter for each attempt to test all delegations, and skip delegations that have already been tested in the current pass. Signed-off-by: Benjamin Coddington Reviewed-by: Jeff Layton --- fs/nfs/delegation.c | 7 ++++++- fs/nfs/delegation.h | 1 + include/linux/nfs_fs_sb.h | 1 + 3 files changed, 8 insertions(+), 1 deletion(-) -- Changed on v2: remove extra brackets that had my debug statements diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index cf7365581031..fa1a14def45c 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -448,6 +448,7 @@ int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred, delegation->cred = get_cred(cred); delegation->inode = inode; delegation->flags = 1<test_gen = 0; spin_lock_init(&delegation->lock); spin_lock(&clp->cl_lock); @@ -1294,6 +1295,8 @@ static int nfs_server_reap_expired_delegations(struct nfs_server *server, struct inode *inode; const struct cred *cred; nfs4_stateid stateid; + unsigned long gen = ++server->delegation_gen; + restart: rcu_read_lock(); restart_locked: @@ -1303,7 +1306,8 @@ static int nfs_server_reap_expired_delegations(struct nfs_server *server, test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) || test_bit(NFS_DELEGATION_TEST_EXPIRED, - &delegation->flags) == 0) + &delegation->flags) == 0 || + delegation->test_gen == gen) continue; inode = nfs_delegation_grab_inode(delegation); if (inode == NULL) @@ -1312,6 +1316,7 @@ static int nfs_server_reap_expired_delegations(struct nfs_server *server, cred = get_cred_rcu(delegation->cred); nfs4_stateid_copy(&stateid, &delegation->stateid); spin_unlock(&delegation->lock); + delegation->test_gen = gen; clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags); rcu_read_unlock(); nfs_delegation_test_free_expired(inode, &stateid, cred); diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h index 1c378992b7c0..a6f495d012cf 100644 --- a/fs/nfs/delegation.h +++ b/fs/nfs/delegation.h @@ -21,6 +21,7 @@ struct nfs_delegation { fmode_t type; unsigned long pagemod_limit; __u64 change_attr; + unsigned long test_gen; unsigned long flags; refcount_t refcount; spinlock_t lock; diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h index 20eeba8b009d..2f9d380b3439 100644 --- a/include/linux/nfs_fs_sb.h +++ b/include/linux/nfs_fs_sb.h @@ -238,6 +238,7 @@ struct nfs_server { struct list_head delegations; struct list_head ss_copies; + unsigned long delegation_gen; unsigned long mig_gen; unsigned long mig_status; #define NFS_MIG_IN_TRANSITION (1)