From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751476Ab3LLKn1 (ORCPT ); Thu, 12 Dec 2013 05:43:27 -0500 Received: from mx1.redhat.com ([209.132.183.28]:3723 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751120Ab3LLKnY (ORCPT ); Thu, 12 Dec 2013 05:43:24 -0500 Date: Thu, 12 Dec 2013 05:43:08 -0500 From: Jeff Layton To: "J. Bruce Fields" Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, nfs-ganesha-devel@lists.sourceforge.net, samba-technical@lists.samba.org Subject: Re: [PATCH v3 1/6] locks: consolidate common code in the flock_to_posix_lock routines Message-ID: <20131212054308.76aa0d37@tlielax.poochiereds.net> In-Reply-To: <20131211225724.GB3483@fieldses.org> References: <1386703055-22308-1-git-send-email-jlayton@redhat.com> <1386703055-22308-2-git-send-email-jlayton@redhat.com> <20131210212253.GC20831@fieldses.org> <20131210232204.GD20831@fieldses.org> <20131211061856.615c39ba@tlielax.poochiereds.net> <20131211143724.GA29300@fieldses.org> <20131211151931.GC29300@fieldses.org> <20131211140741.292028e8@tlielax.poochiereds.net> <20131211225616.GA3483@fieldses.org> <20131211225724.GB3483@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 11 Dec 2013 17:57:24 -0500 "J. Bruce Fields" wrote: > On Wed, Dec 11, 2013 at 05:56:16PM -0500, J. Bruce Fields wrote: > > On Wed, Dec 11, 2013 at 02:07:41PM -0500, Jeff Layton wrote: > > > On Wed, 11 Dec 2013 10:19:31 -0500 > > > "J. Bruce Fields" wrote: > > ... > > > > + if (l->l_len > 0) > > > > + fl->fl_end = fl->fl_start + l->l_len - 1; > > > > + else if (l->l_len < 0) { > > > > + fl->fl_end = start - 1; > > > > > > Erm... I think this is not quite right... > > > > > > "start" is uninitialized here. I think this should be: > > > > > > fl->fl_end = fl->fl_start - 1 > > > > > > With that too, we can get rid of the local "start" variable. I think > > > this may explain why I'm tripping over the BUG() in locks_remove_file. > > > > Yep. > > > > One other bug: I think l_start < 0 is actually fine in the > > SEEK_CUR/SEEK_END cases. > > > > With that fixed and another comment (though I don't know how much it > > helps), it looks like the below. > > Alternatively, maybe we could simplify? (On top of the previous): > > commit d4bf5cb021a3ac1ec07530ebda904e262cc89d11 > Author: J. Bruce Fields > Date: Wed Dec 11 17:42:32 2013 -0500 > > locks: simplify overflow checking > > Or maybe we don't actually care about indicating overflow in the 32-bit > case: sure we could fail if e.g. f_pos+start or f_pos+start+len would > exceed 32-bits, but do we really need to? > > Signed-off-by: J. Bruce Fields > > diff --git a/fs/locks.c b/fs/locks.c > index 39f2ca9..efbf577 100644 > --- a/fs/locks.c > +++ b/fs/locks.c > @@ -344,8 +344,8 @@ static int assign_type(struct file_lock *fl, long type) > return 0; > } > > -static int flock_to_posix_lock_common(struct file *filp, struct file_lock *fl, > - struct flock64 *l, loff_t offset_max) > +static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, > + struct flock64 *l) > { > switch (l->l_whence) { > case SEEK_SET: > @@ -360,12 +360,12 @@ static int flock_to_posix_lock_common(struct file *filp, struct file_lock *fl, > default: > return -EINVAL; > } > - if (l->l_start > offset_max - fl->fl_start) > + if (l->l_start > OFFSET_MAX - fl->fl_start) > return -EOVERFLOW; > fl->fl_start += l->l_start; > if (fl->fl_start < 0) > return -EINVAL; > - if (l->l_len > offset_max - fl->fl_start) > + if (l->l_len > OFFSET_MAX - fl->fl_start) > return -EOVERFLOW; > if (fl->fl_start + l->l_len < 0) > return -EINVAL; > @@ -403,22 +403,9 @@ static int flock_to_posix_lock(struct file *filp, struct file_lock *fl, > .l_len = l->l_len, > }; > > - /* > - * The use of OFFT_OFFSET_MAX here ensures we return -EOVERFLOW > - * if the start or end of the lock could not be represented as > - * an off_t, following SUSv3. > - */ > - return flock_to_posix_lock_common(filp, fl, &ll, OFFT_OFFSET_MAX); > + return flock64_to_posix_lock(filp, fl, &ll); > } > > -#if BITS_PER_LONG == 32 > -static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, > - struct flock64 *l) > -{ > - return flock_to_posix_lock_common(filp, fl, l, OFFSET_MAX); > -} > -#endif > - > /* default lease lock manager operations */ > static void lease_break_callback(struct file_lock *fl) > { Makes sense to me -- be liberal in what you accept and all that... It might be problematic for 32-bit apps that then later try to do F_GETLK against such a lock, I doubt that'll be any worse than the current situation. I'll toss this one onto the pile... Thanks! -- Jeff Layton