From patchwork Mon Nov 30 19:38:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "J. Bruce Fields" X-Patchwork-Id: 11941217 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 81DE5C64E8A for ; Mon, 30 Nov 2020 19:39:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4739207F7 for ; Mon, 30 Nov 2020 19:39:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="IxAqM29v" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729608AbgK3Tjk (ORCPT ); Mon, 30 Nov 2020 14:39:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729952AbgK3Tjk (ORCPT ); Mon, 30 Nov 2020 14:39:40 -0500 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F0675C0613D4 for ; Mon, 30 Nov 2020 11:38:59 -0800 (PST) Received: by fieldses.org (Postfix, from userid 2815) id 5BCC742A8; Mon, 30 Nov 2020 14:38:58 -0500 (EST) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 5BCC742A8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1606765138; bh=8anUsUDZvLN0iJd/CpARwqjHQ4Ao21m65dIWFIirwd0=; h=From:To:Cc:Subject:Date:From; b=IxAqM29vw3R/UZXqm5eGOGQx5biYMAJFL+wOhRlkpOZL7c1gS5WvJlGEOWtxWjJeP r3vpqnTyufwnz8uaIndatr0qM3oAJNGRYomgy61Wye9PRB4D+nzxFxYmlIM9FPNyh6 WUoNFMe2ephWID3uZ9pJU7X+09dkyIrAULR+j1lg= From: "J. Bruce Fields" To: Chuck Lever Cc: linux-nfs@vger.kernel.org, "J. Bruce Fields" Subject: [PATCH 1/5] nfsd: only call inode_query_iversion in the I_VERSION case Date: Mon, 30 Nov 2020 14:38:53 -0500 Message-Id: <1606765137-17257-1-git-send-email-bfields@fieldses.org> X-Mailer: git-send-email 1.8.3.1 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: "J. Bruce Fields" inode_query_iversion() can modify i_version. Depending on the exported filesystem, that may not be safe. For example, if you're re-exporting NFS, NFS stores the server's change attribute in i_version and does not expect it to be modified locally. This has been observed causing unnecessary cache invalidations. The way a filesystem indicates that it's OK to call inode_query_iverson() is by setting SB_I_VERSION. So, move the I_VERSION check out of encode_change(), where it's used only in FATTR responses, to nfsd4_changeattr(), which is also called for pre- and post- operation attributes. (Note we could also pull the NFSEXP_V4ROOT case into nfsd4_change_attribute as well. That would actually be a no-op, since pre/post attrs are only used for metadata-modifying operations, and V4ROOT exports are read-only. But we might make the change in the future just for simplicity.) Reported-by: Daire Byrne Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs3xdr.c | 5 ++--- fs/nfsd/nfs4xdr.c | 6 +----- fs/nfsd/nfsfh.h | 14 ++++++++++---- 3 files changed, 13 insertions(+), 12 deletions(-) diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c index 2277f83da250..dfbf390ff40c 100644 --- a/fs/nfsd/nfs3xdr.c +++ b/fs/nfsd/nfs3xdr.c @@ -291,14 +291,13 @@ void fill_post_wcc(struct svc_fh *fhp) printk("nfsd: inode locked twice during operation.\n"); err = fh_getattr(fhp, &fhp->fh_post_attr); - fhp->fh_post_change = nfsd4_change_attribute(&fhp->fh_post_attr, - d_inode(fhp->fh_dentry)); if (err) { fhp->fh_post_saved = false; - /* Grab the ctime anyway - set_change_info might use it */ fhp->fh_post_attr.ctime = d_inode(fhp->fh_dentry)->i_ctime; } else fhp->fh_post_saved = true; + fhp->fh_post_change = nfsd4_change_attribute(&fhp->fh_post_attr, + d_inode(fhp->fh_dentry)); } /* diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 833a2c64dfe8..56fd5f6d5c44 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -2298,12 +2298,8 @@ static __be32 *encode_change(__be32 *p, struct kstat *stat, struct inode *inode, if (exp->ex_flags & NFSEXP_V4ROOT) { *p++ = cpu_to_be32(convert_to_wallclock(exp->cd->flush_time)); *p++ = 0; - } else if (IS_I_VERSION(inode)) { + } else p = xdr_encode_hyper(p, nfsd4_change_attribute(stat, inode)); - } else { - *p++ = cpu_to_be32(stat->ctime.tv_sec); - *p++ = cpu_to_be32(stat->ctime.tv_nsec); - } return p; } diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h index 56cfbc361561..3faf5974fa4e 100644 --- a/fs/nfsd/nfsfh.h +++ b/fs/nfsd/nfsfh.h @@ -261,10 +261,16 @@ static inline u64 nfsd4_change_attribute(struct kstat *stat, { u64 chattr; - chattr = stat->ctime.tv_sec; - chattr <<= 30; - chattr += stat->ctime.tv_nsec; - chattr += inode_query_iversion(inode); + if (IS_I_VERSION(inode)) { + chattr = stat->ctime.tv_sec; + chattr <<= 30; + chattr += stat->ctime.tv_nsec; + chattr += inode_query_iversion(inode); + } else { + chattr = cpu_to_be32(stat->ctime.tv_sec); + chattr <<= 32; + chattr += cpu_to_be32(stat->ctime.tv_nsec); + } return chattr; }