From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 195B2C4338F for ; Wed, 28 Jul 2021 02:29:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC33660FA0 for ; Wed, 28 Jul 2021 02:29:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233374AbhG1C3Z (ORCPT ); Tue, 27 Jul 2021 22:29:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:33884 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233223AbhG1C3Z (ORCPT ); Tue, 27 Jul 2021 22:29:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7069F60F9D; Wed, 28 Jul 2021 02:29:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627439364; bh=92/QU5E2eSQ6Mi3MNPH50dd6V05Hb7i5VrQtXsDNLTo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sngqlEFdZ1mpdSmM5PMlNOmlefHphaw0iNtvYJjbHzNcP7420wr+CKetnrlksePur aejSQgZbvhFwgqUm6+p1O054oZMR+q6GVxJzE+RiSgaJiP1Z87znO7NMDCVXBtANAT oWEL9N7F5jY+1NJ9qwJthdTmYyMvnhD3CX9CXBS60bn8k7UPy+BwFzXyI6s7JdxBue mN+YTqXdHR5rDvjH3CuS7qsjthNPZPeTpCs4GCtSpaBbG8sWzyEvUupdBjkUpsoLCe GZzHTlnLkHEbDv9iUKo+0likZYp16Bs2oyrEJkd+nJEs1vbL4e9NfKyTi3+KHBzb0V fvfy9XVBs+gYw== Date: Tue, 27 Jul 2021 19:29:23 -0700 From: Jaegeuk Kim To: Eric Biggers Cc: Chao Yu , linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, Satya Tangirala , Changheun Lee , Matthew Bobrowski Subject: Re: [PATCH 3/9] f2fs: rework write preallocations Message-ID: References: <20210716143919.44373-1-ebiggers@kernel.org> <20210716143919.44373-4-ebiggers@kernel.org> <14782036-f6a5-878a-d21f-e7dd7008a285@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On 07/26, Jaegeuk Kim wrote: > On 07/25, Eric Biggers wrote: > > On Sun, Jul 25, 2021 at 06:50:51PM +0800, Chao Yu wrote: > > > On 2021/7/16 22:39, Eric Biggers wrote: > > > > From: Eric Biggers > > > > > > > > f2fs_write_begin() assumes that all blocks were preallocated by > > > > default unless FI_NO_PREALLOC is explicitly set. This invites data > > > > corruption, as there are cases in which not all blocks are preallocated. > > > > Commit 47501f87c61a ("f2fs: preallocate DIO blocks when forcing > > > > buffered_io") fixed one case, but there are others remaining. > > > > > > Could you please explain which cases we missed to handle previously? > > > then I can check those related logic before and after the rework. > > > > Any case where a buffered write happens while not all blocks were preallocated > > but FI_NO_PREALLOC wasn't set. For example when ENOSPC was hit in the middle of > > the preallocations for a direct write that will fall back to a buffered write, > > e.g. due to f2fs_force_buffered_io() or page cache invalidation failure. > > > > > > > > > - /* > > > > - * If force_buffere_io() is true, we have to allocate > > > > - * blocks all the time, since f2fs_direct_IO will fall > > > > - * back to buffered IO. > > > > - */ > > > > - if (!f2fs_force_buffered_io(inode, iocb, from) && > > > > - f2fs_lfs_mode(F2FS_I_SB(inode))) > > > > - goto write; > > > > > > We should keep this OPU DIO logic, otherwise, in lfs mode, write dio > > > will always allocate two block addresses for each 4k append IO. > > > > > > I jsut test based on codes of last f2fs dev-test branch. > > > > Yes, I had misread that due to the weird goto and misleading comment and > > translated it into: > > > > /* If it will be an in-place direct write, don't bother. */ > > if (dio && !f2fs_lfs_mode(sbi)) > > return 0; > > > > It should be: > > > > if (dio && f2fs_lfs_mode(sbi)) > > return 0; > > Hmm, this addresses my 250 failure. And, I think the below commit can explain > the case. In addition to this, I got failure on generic/263, and the below change fixes it. (I didn't take a look at deeply tho.) --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -4344,8 +4344,13 @@ static int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *iter) return ret; } - map.m_lblk = (pos >> inode->i_blkbits); - map.m_len = ((pos + count - 1) >> inode->i_blkbits) - map.m_lblk + 1; + map.m_lblk = F2FS_BLK_ALIGN(pos); + map.m_len = F2FS_BYTES_TO_BLK(pos + count); + if (map.m_len > map.m_lblk) + map.m_len -= map.m_lblk; + else + map.m_len = 0; +