From owner-svn-src-all@freebsd.org Thu Dec 5 13:41:22 2019 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id D2DC51CA056; Thu, 5 Dec 2019 13:41:22 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 47TH1Z5DfLz4D1P; Thu, 5 Dec 2019 13:41:22 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 96CA019AC0; Thu, 5 Dec 2019 13:41:22 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id xB5DfMVO087837; Thu, 5 Dec 2019 13:41:22 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id xB5DfMdc087836; Thu, 5 Dec 2019 13:41:22 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <201912051341.xB5DfMdc087836@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Thu, 5 Dec 2019 13:41:22 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r355415 - head/sys/fs/nullfs X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/fs/nullfs X-SVN-Commit-Revision: 355415 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Dec 2019 13:41:22 -0000 Author: mjg Date: Thu Dec 5 13:41:22 2019 New Revision: 355415 URL: https://svnweb.freebsd.org/changeset/base/355415 Log: nullfs: locklessly check for entries in null_hashget During random sampling over poudriere -j 104 over 10% of calls returned NULL. Modified: head/sys/fs/nullfs/null_subr.c Modified: head/sys/fs/nullfs/null_subr.c ============================================================================== --- head/sys/fs/nullfs/null_subr.c Thu Dec 5 13:40:10 2019 (r355414) +++ head/sys/fs/nullfs/null_subr.c Thu Dec 5 13:41:22 2019 (r355415) @@ -113,6 +113,8 @@ null_hashget(mp, lowervp) * reference count (but NOT the lower vnode's VREF counter). */ hd = NULL_NHASH(lowervp); + if (LIST_EMPTY(hd)) + return (NULLVP); rw_rlock(&null_hash_lock); LIST_FOREACH(a, hd, null_hash) { if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {