From owner-svn-src-all@freebsd.org Mon Aug 31 05:25:14 2020 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 3C3E83D63B7; Mon, 31 Aug 2020 05:25:14 +0000 (UTC) (envelope-from mckusick@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 4BfzDV0t8wz44JS; Mon, 31 Aug 2020 05:25:14 +0000 (UTC) (envelope-from mckusick@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 0154F22AD5; Mon, 31 Aug 2020 05:25:14 +0000 (UTC) (envelope-from mckusick@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 07V5PDU1039747; Mon, 31 Aug 2020 05:25:13 GMT (envelope-from mckusick@FreeBSD.org) Received: (from mckusick@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 07V5PD1w039746; Mon, 31 Aug 2020 05:25:13 GMT (envelope-from mckusick@FreeBSD.org) Message-Id: <202008310525.07V5PD1w039746@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mckusick set sender to mckusick@FreeBSD.org using -f From: Kirk McKusick Date: Mon, 31 Aug 2020 05:25:13 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r364983 - stable/12/sys/kern X-SVN-Group: stable-12 X-SVN-Commit-Author: mckusick X-SVN-Commit-Paths: stable/12/sys/kern X-SVN-Commit-Revision: 364983 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: 2.1.33 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: Mon, 31 Aug 2020 05:25:14 -0000 Author: mckusick Date: Mon Aug 31 05:25:13 2020 New Revision: 364983 URL: https://svnweb.freebsd.org/changeset/base/364983 Log: MFC of 364895 Comment on when and why pathnames are deleted from the name cache. Modified: stable/12/sys/kern/vfs_lookup.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/kern/vfs_lookup.c ============================================================================== --- stable/12/sys/kern/vfs_lookup.c Mon Aug 31 01:45:48 2020 (r364982) +++ stable/12/sys/kern/vfs_lookup.c Mon Aug 31 05:25:13 2020 (r364983) @@ -663,6 +663,16 @@ lookup(struct nameidata *ndp) wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); KASSERT(cnp->cn_nameiop == LOOKUP || wantparent, ("CREATE, DELETE, RENAME require LOCKPARENT or WANTPARENT.")); + /* + * When set to zero, docache causes the last component of the + * pathname to be deleted from the cache and the full lookup + * of the name to be done (via VOP_CACHEDLOOKUP()). Often + * filesystems need some pre-computed values that are made + * during the full lookup, for instance UFS sets dp->i_offset. + * + * The docache variable is set to zero when requested by the + * NOCACHE flag and for all modifying operations except CREATE. + */ docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; if (cnp->cn_nameiop == DELETE || (wantparent && cnp->cn_nameiop != CREATE &&