From owner-svn-src-head@freebsd.org Thu Jul 2 08:32:04 2015 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2CAD4993BEA; Thu, 2 Jul 2015 08:32:04 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 032B82FEF; Thu, 2 Jul 2015 08:32:04 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.70]) by repo.freebsd.org (8.14.9/8.14.9) with ESMTP id t628W3gR002945; Thu, 2 Jul 2015 08:32:03 GMT (envelope-from avg@FreeBSD.org) Received: (from avg@localhost) by repo.freebsd.org (8.14.9/8.14.9/Submit) id t628W3WJ002944; Thu, 2 Jul 2015 08:32:03 GMT (envelope-from avg@FreeBSD.org) Message-Id: <201507020832.t628W3WJ002944@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: avg set sender to avg@FreeBSD.org using -f From: Andriy Gapon Date: Thu, 2 Jul 2015 08:32:03 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r285021 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs X-SVN-Group: head 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: 2.1.20 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 2015 08:32:04 -0000 Author: avg Date: Thu Jul 2 08:32:02 2015 New Revision: 285021 URL: https://svnweb.freebsd.org/changeset/base/285021 Log: zfs_mount(MS_REMOUNT): protect zfs_(un)register_callbacks calls We now take z_teardown_lock as a writer to ensure that there is no I/O while the filesystem state is in a flux. Also, zfs_suspend_fs() -> zfsvfs_teardown() call zfs_unregister_callbacks() and zfs_resume_fs() -> zfsvfs_setup() call zfs_unregister_callbacks(). Previously there was no synchronization between those calls and the calls in the re-mounting case. That could lead to concurrent execution and a crash. PR: 180060 Differential Revision: https://reviews.freebsd.org/D2865 Suggested by: mahrens Reviewed by: delphij, pho, mahrens, will MFC after: 13 days Sponsored by: ClusterHQ Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c Thu Jul 2 08:25:45 2015 (r285020) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c Thu Jul 2 08:32:02 2015 (r285021) @@ -1717,9 +1717,19 @@ zfs_mount(vfs_t *vfsp) * according to those options set in the current VFS options. */ if (vfsp->vfs_flag & MS_REMOUNT) { - /* refresh mount options */ - zfs_unregister_callbacks(vfsp->vfs_data); + zfsvfs_t *zfsvfs = vfsp->vfs_data; + + /* + * Refresh mount options with z_teardown_lock blocking I/O while + * the filesystem is in an inconsistent state. + * The lock also serializes this code with filesystem + * manipulations between entry to zfs_suspend_fs() and return + * from zfs_resume_fs(). + */ + rrm_enter(&zfsvfs->z_teardown_lock, RW_WRITER, FTAG); + zfs_unregister_callbacks(zfsvfs); error = zfs_register_callbacks(vfsp); + rrm_exit(&zfsvfs->z_teardown_lock, FTAG); goto out; }