From owner-svn-src-head@freebsd.org Thu Jul 2 12:54:51 2020 Return-Path: Delivered-To: svn-src-head@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 48763355E8E; Thu, 2 Jul 2020 12:54:51 +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) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 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 49yJ2z1Fj2z3Xj8; Thu, 2 Jul 2020 12:54:51 +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 0EBD91AF37; Thu, 2 Jul 2020 12:54:51 +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 062Csogp086779; Thu, 2 Jul 2020 12:54:50 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 062Cso12086778; Thu, 2 Jul 2020 12:54:50 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <202007021254.062Cso12086778@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Thu, 2 Jul 2020 12:54:50 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r362888 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 362888 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 Jul 2020 12:54:51 -0000 Author: mjg Date: Thu Jul 2 12:54:50 2020 New Revision: 362888 URL: https://svnweb.freebsd.org/changeset/base/362888 Log: cache: fix misplaced fence in cache_ncp_invalidate The intent was to mark the entry as invalid before cache_zap starts messing with it. While here add some comments. Modified: head/sys/kern/vfs_cache.c Modified: head/sys/kern/vfs_cache.c ============================================================================== --- head/sys/kern/vfs_cache.c Thu Jul 2 10:44:45 2020 (r362887) +++ head/sys/kern/vfs_cache.c Thu Jul 2 12:54:50 2020 (r362888) @@ -147,22 +147,33 @@ struct namecache_ts { #define NCF_HOTNEGATIVE 0x40 #define NCF_INVALID 0x80 -static bool -cache_ncp_invalid(struct namecache *ncp) -{ - - atomic_thread_fence_acq(); - return ((ncp->nc_flag & NCF_INVALID) != 0); -} - +/* + * Mark an entry as invalid. + * + * This is called before it starts getting deconstructed. + */ static void cache_ncp_invalidate(struct namecache *ncp) { - atomic_thread_fence_rel(); KASSERT((ncp->nc_flag & NCF_INVALID) == 0, ("%s: entry %p already invalid", __func__, ncp)); ncp->nc_flag |= NCF_INVALID; + atomic_thread_fence_rel(); +} + +/* + * Verify validity of an entry. + * + * All places which elide locks are supposed to call this after they are + * done with reading from an entry. + */ +static bool +cache_ncp_invalid(struct namecache *ncp) +{ + + atomic_thread_fence_acq(); + return ((ncp->nc_flag & NCF_INVALID) != 0); } /*