Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755148AbZGFGXd (ORCPT ); Mon, 6 Jul 2009 02:23:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752778AbZGFGXZ (ORCPT ); Mon, 6 Jul 2009 02:23:25 -0400 Received: from mx2.redhat.com ([66.187.237.31]:38622 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752554AbZGFGXY (ORCPT ); Mon, 6 Jul 2009 02:23:24 -0400 Message-ID: <4A5198A0.6030904@redhat.com> Date: Mon, 06 Jul 2009 14:24:32 +0800 From: Amerigo Wang User-Agent: Thunderbird 2.0.0.21 (X11/20090319) MIME-Version: 1.0 To: Arjan van de Ven CC: linux-kernel@vger.kernel.org, Jeff Mahoney , Yan Zheng , Josef Bacik , Chris Mason , akpm@linux-foundation.org, linux-btrfs@vger.kernel.org, Sven Wegener Subject: Re: [Patch] btrfs: use file_remove_suid() after i_mutex is held References: <20090706053128.6318.16410.sendpatchset@localhost.localdomain> <20090705224823.5679075f@infradead.org> In-Reply-To: <20090705224823.5679075f@infradead.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1460 Lines: 54 Arjan van de Ven wrote: > On Mon, 6 Jul 2009 01:29:14 -0400 > Amerigo Wang wrote: > > >> file_remove_suid() should be called with i_mutex held, >> file_update_time() too. So move them after mutex_lock(). >> >> Plus, check the return value of kmalloc(). >> >> Signed-off-by: WANG Cong >> >> --- >> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c >> index 7c3cd24..cd36301 100644 >> --- a/fs/btrfs/file.c >> +++ b/fs/btrfs/file.c >> @@ -944,14 +944,17 @@ static ssize_t btrfs_file_write(struct file >> *file, const char __user *buf, if (count == 0) >> goto out_nolock; >> >> + mutex_lock(&inode->i_mutex); >> + >> err = file_remove_suid(file); >> if (err) >> - goto out_nolock; >> + goto out; >> file_update_time(file); >> >> pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); >> + if (!pages) >> + goto out; >> >> > Hi, > > I don't think you can keep this at GFP_KERNEL once you hold i_mutex.... > very likely this needs to now turn into GFP_NOFS! > Good point! Hmm, GFP_KERNEL adds __GFP_FS while GFP_NOFS not... Just moving that kmalloc() up, before mutex_lock(), I think, can solve this. I will update this patch now... Thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/