From owner-svn-src-head@FreeBSD.ORG Thu Jan 8 12:47:30 2009 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A6AE5106564A; Thu, 8 Jan 2009 12:47:30 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 943138FC16; Thu, 8 Jan 2009 12:47:30 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id n08ClUra022669; Thu, 8 Jan 2009 12:47:30 GMT (envelope-from kib@svn.freebsd.org) Received: (from kib@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id n08ClUT2022668; Thu, 8 Jan 2009 12:47:30 GMT (envelope-from kib@svn.freebsd.org) Message-Id: <200901081247.n08ClUT2022668@svn.freebsd.org> From: Konstantin Belousov Date: Thu, 8 Jan 2009 12:47:30 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r186896 - head/sys/kern X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 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, 08 Jan 2009 12:47:31 -0000 Author: kib Date: Thu Jan 8 12:47:30 2009 New Revision: 186896 URL: http://svn.freebsd.org/changeset/base/186896 Log: Do not call namei() while having another user-controlled vnode locked. Lookup could attempt to recursively lock that vnode. Do not call vn_start_write(V_WAIT) while vnode is locked, this may result in a deadlock with suspension. vfs_busy() the mountpoint before dropping vnode lock for vnode that was used to look up the mountpoint, to prevent unmount in between. Reported and tested by: pho Reviewed by: rwatson MFC after: 3 weeks Modified: head/sys/kern/vfs_extattr.c Modified: head/sys/kern/vfs_extattr.c ============================================================================== --- head/sys/kern/vfs_extattr.c Thu Jan 8 12:39:40 2009 (r186895) +++ head/sys/kern/vfs_extattr.c Thu Jan 8 12:47:30 2009 (r186896) @@ -87,52 +87,65 @@ extattrctl(td, uap) AUDIT_ARG(text, attrname); vfslocked = fnvfslocked = 0; - /* - * uap->filename is not always defined. If it is, grab a vnode lock, - * which VFS_EXTATTRCTL() will later release. - */ + mp = NULL; filename_vp = NULL; if (uap->filename != NULL) { - NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF | - AUDITVNODE2, UIO_USERSPACE, uap->filename, td); + NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | AUDITVNODE2, + UIO_USERSPACE, uap->filename, td); error = namei(&nd); if (error) return (error); fnvfslocked = NDHASGIANT(&nd); filename_vp = nd.ni_vp; - NDFREE(&nd, NDF_NO_VP_RELE | NDF_NO_VP_UNLOCK); + NDFREE(&nd, NDF_NO_VP_RELE); } /* uap->path is always defined. */ - NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | AUDITVNODE1, UIO_USERSPACE, - uap->path, td); + NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF | AUDITVNODE1, + UIO_USERSPACE, uap->path, td); error = namei(&nd); - if (error) { - if (filename_vp != NULL) - vput(filename_vp); + if (error) goto out; - } vfslocked = NDHASGIANT(&nd); mp = nd.ni_vp->v_mount; - error = vn_start_write(nd.ni_vp, &mp_writable, V_WAIT | PCATCH); - NDFREE(&nd, 0); + error = vfs_busy(mp, 0); if (error) { - if (filename_vp != NULL) - vput(filename_vp); + NDFREE(&nd, 0); + mp = NULL; goto out; } + VOP_UNLOCK(nd.ni_vp, 0); + error = vn_start_write(nd.ni_vp, &mp_writable, V_WAIT | PCATCH); + NDFREE(&nd, NDF_NO_VP_UNLOCK); + if (error) + goto out; + if (filename_vp != NULL) { + /* + * uap->filename is not always defined. If it is, + * grab a vnode lock, which VFS_EXTATTRCTL() will + * later release. + */ + error = vn_lock(filename_vp, LK_EXCLUSIVE); + if (error) { + vn_finished_write(mp_writable); + goto out; + } + } error = VFS_EXTATTRCTL(mp, uap->cmd, filename_vp, uap->attrnamespace, uap->attrname != NULL ? attrname : NULL, td); vn_finished_write(mp_writable); +out: + if (mp != NULL) + vfs_unbusy(mp); + /* * VFS_EXTATTRCTL will have unlocked, but not de-ref'd, filename_vp, * so vrele it if it is defined. */ if (filename_vp != NULL) vrele(filename_vp); -out: VFS_UNLOCK_GIANT(fnvfslocked); VFS_UNLOCK_GIANT(vfslocked); return (error);