From owner-svn-src-head@freebsd.org Mon Sep 9 11:22:39 2019 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 54156F5E28; Mon, 9 Sep 2019 11:22:39 +0000 (UTC) (envelope-from kib@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 46Rm3g16dsz3LSD; Mon, 9 Sep 2019 11:22:39 +0000 (UTC) (envelope-from kib@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 09AB1CD9F; Mon, 9 Sep 2019 11:22:39 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x89BMcrh061511; Mon, 9 Sep 2019 11:22:38 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x89BMc0D061510; Mon, 9 Sep 2019 11:22:38 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201909091122.x89BMc0D061510@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Mon, 9 Sep 2019 11:22:38 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r352058 - head/sys/ufs/ffs X-SVN-Group: head X-SVN-Commit-Author: kib X-SVN-Commit-Paths: head/sys/ufs/ffs X-SVN-Commit-Revision: 352058 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: 2.1.29 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: Mon, 09 Sep 2019 11:22:39 -0000 Author: kib Date: Mon Sep 9 11:22:38 2019 New Revision: 352058 URL: https://svnweb.freebsd.org/changeset/base/352058 Log: Remove some unneeded vfs_busy() calls in SU code. When softdep_fsync() is running, a caller must already started write for the mount point. Since unmount or remount to ro suspends mount point, it cannot run in parallel with softdep_fsync(), which makes vfs_busy() call there not needed. Doing blocking vfs_busy() there effectively causes lock order reversal between vn_start_write() and setting MNTK_UNMOUNT, because vfs_busy(mp, 0) sleeps waiting for MNTK_UNMOUNT becoming clear, while unmount sets the flag and starts the suspension. Note that all other uses of vfs_busy() in SU code are non-blocking. Reported by: chs by mckusick Reviewed by: mckusick Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/sys/ufs/ffs/ffs_softdep.c Modified: head/sys/ufs/ffs/ffs_softdep.c ============================================================================== --- head/sys/ufs/ffs/ffs_softdep.c Mon Sep 9 11:20:15 2019 (r352057) +++ head/sys/ufs/ffs/ffs_softdep.c Mon Sep 9 11:22:38 2019 (r352058) @@ -12507,24 +12507,13 @@ restart: FREE_LOCK(ump); if (ffs_vgetf(mp, parentino, LK_NOWAIT | LK_EXCLUSIVE, &pvp, FFSV_FORCEINSMQ)) { - error = vfs_busy(mp, MBF_NOWAIT); - if (error != 0) { - vfs_ref(mp); - VOP_UNLOCK(vp, 0); - error = vfs_busy(mp, 0); - vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); - vfs_rel(mp); - if (error != 0) - return (ENOENT); - if (vp->v_iflag & VI_DOOMED) { - vfs_unbusy(mp); - return (ENOENT); - } - } + /* + * Unmount cannot proceed after unlock because + * caller must have called vn_start_write(). + */ VOP_UNLOCK(vp, 0); error = ffs_vgetf(mp, parentino, LK_EXCLUSIVE, &pvp, FFSV_FORCEINSMQ); - vfs_unbusy(mp); vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); if (vp->v_iflag & VI_DOOMED) { if (error == 0)