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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 C3697C433FE for ; Thu, 9 Sep 2021 12:04:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A64D860041 for ; Thu, 9 Sep 2021 12:04:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348028AbhIIMEk (ORCPT ); Thu, 9 Sep 2021 08:04:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:41392 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345014AbhIIL7c (ORCPT ); Thu, 9 Sep 2021 07:59:32 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 490C661425; Thu, 9 Sep 2021 11:46:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631187961; bh=O4QDUrrhok5Yx1hnbaku5IUMizrFXg2FjhyeUpa7OvE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J+moTNGtF37LH0dSo3DOCwTMc6Br5Vsx51QFb62zc1h7igoxJ1CM4s1CpCi0LNHyB hNODAOlkiXXDrO7yiNTt4X3MtRNj5DGxzxp9bel7aZOfwPOEIBRER4Mi2EdZZCLHlY 2onDpR3L3XqHmz7BXLdsG1DNVu+clPmiPZFgLzdrCWaHOIfPYSTJyRjh6KA2oB2F68 5KKSqSStzH3AWiFgvnBH7huJ2grrlXc2Nk+LhspiwX0Fku5Ah5emvtiYE5MMMe+F6l 9vNAdHF+9qrhD5MU4YVmu5G+KzHZ7j7MlJ8EuHeRAA0Eu72jOGQNrz3/FWwF3zbrzo Dg2e5EVTG/AOQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "J. Bruce Fields" , Anna Schumaker , Chuck Lever , Sasha Levin , linux-nfs@vger.kernel.org Subject: [PATCH AUTOSEL 5.14 226/252] nfs: don't atempt blocking locks on nfs reexports Date: Thu, 9 Sep 2021 07:40:40 -0400 Message-Id: <20210909114106.141462-226-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210909114106.141462-1-sashal@kernel.org> References: <20210909114106.141462-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "J. Bruce Fields" [ Upstream commit f657f8eef3ff870552c9fd2839e0061046f44618 ] NFS implements blocking locks by blocking inside its lock method. In the reexport case, this blocks the nfs server thread, which could lead to deadlocks since an nfs server thread might be required to unlock the conflicting lock. It also causes a crash, since the nfs server thread assumes it can free the lock when its lm_notify lock callback is called. Ideal would be to make the nfs lock method return without blocking in this case, but for now it works just not to attempt blocking locks. The difference is just that the original client will have to poll (as it does in the v4.0 case) instead of getting a callback when the lock's available. Signed-off-by: J. Bruce Fields Acked-by: Anna Schumaker Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfs/export.c | 2 +- fs/nfsd/nfs4state.c | 8 ++++++-- include/linux/exportfs.h | 2 ++ 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/fs/nfs/export.c b/fs/nfs/export.c index 37a1a88df771..d772c20bbfd1 100644 --- a/fs/nfs/export.c +++ b/fs/nfs/export.c @@ -180,5 +180,5 @@ const struct export_operations nfs_export_ops = { .fetch_iversion = nfs_fetch_iversion, .flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK| EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS| - EXPORT_OP_NOATOMIC_ATTR, + EXPORT_OP_NOATOMIC_ATTR|EXPORT_OP_SYNC_LOCKS, }; diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index fa67ecd5fe63..bebe86cce7c7 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -6835,6 +6835,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, struct nfsd4_blocked_lock *nbl = NULL; struct file_lock *file_lock = NULL; struct file_lock *conflock = NULL; + struct super_block *sb; __be32 status = 0; int lkflg; int err; @@ -6856,6 +6857,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, dprintk("NFSD: nfsd4_lock: permission denied!\n"); return status; } + sb = cstate->current_fh.fh_dentry->d_sb; if (lock->lk_is_new) { if (nfsd4_has_session(cstate)) @@ -6904,7 +6906,8 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, fp = lock_stp->st_stid.sc_file; switch (lock->lk_type) { case NFS4_READW_LT: - if (nfsd4_has_session(cstate)) + if (nfsd4_has_session(cstate) && + !(sb->s_export_op->flags & EXPORT_OP_SYNC_LOCKS)) fl_flags |= FL_SLEEP; fallthrough; case NFS4_READ_LT: @@ -6916,7 +6919,8 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, fl_type = F_RDLCK; break; case NFS4_WRITEW_LT: - if (nfsd4_has_session(cstate)) + if (nfsd4_has_session(cstate) && + !(sb->s_export_op->flags & EXPORT_OP_SYNC_LOCKS)) fl_flags |= FL_SLEEP; fallthrough; case NFS4_WRITE_LT: diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h index fe848901fcc3..3260fe714846 100644 --- a/include/linux/exportfs.h +++ b/include/linux/exportfs.h @@ -221,6 +221,8 @@ struct export_operations { #define EXPORT_OP_NOATOMIC_ATTR (0x10) /* Filesystem cannot supply atomic attribute updates */ +#define EXPORT_OP_SYNC_LOCKS (0x20) /* Filesystem can't do + asychronous blocking locks */ unsigned long flags; }; -- 2.30.2