From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Sandeen Subject: Re: [PATCH] ext4_freeze: don't return to userspace with a mutex held Date: Sun, 04 Apr 2010 16:23:32 -0500 Message-ID: <4BB90354.3040300@redhat.com> References: <4BB12B03.9070906@redhat.com> <20100404205237.GK18524@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: ext4 development To: tytso@mit.edu Return-path: Received: from mx1.redhat.com ([209.132.183.28]:52935 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751986Ab0DDVXk (ORCPT ); Sun, 4 Apr 2010 17:23:40 -0400 In-Reply-To: <20100404205237.GK18524@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: tytso@mit.edu wrote: > On Mon, Mar 29, 2010 at 05:34:43PM -0500, Eric Sandeen wrote: >> I don't -think- we need to do this; by now we should have s_frozen >> set, and nobody else should be coming down the pipe to get to >> the journal. However, just to be on the safe side, I added >> a couple of vfs_check_frozen() calls in ext4 functions which will >> arrive at start_this_handle(), which should ensure that we never >> get any journal traffic generated while frozen. > > Um, I think the addition of vfs_check_frozen(), esp. to > ext4_journal_start_sb() is absolutely necessary. What else do we have > to prevent filesystem modifications from going to the file systme > layer? I didn't see anything in the VFS layer that checks s_frozen; > am I missing something? > > - Ted Well, there is __generic_file_aio_write doing vfs_check_frozen, but I thought there was more at the vfs level to stop things from getting to the filesystem... *shrug* I see you put the patch in as sent, it sounds right to me. Thanks, -Eric