From patchwork Tue Oct 3 16:02:01 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eryu Guan X-Patchwork-Id: 9983167 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A40A5602B8 for ; Tue, 3 Oct 2017 16:03:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 95A9E28A12 for ; Tue, 3 Oct 2017 16:03:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8A71C28A18; Tue, 3 Oct 2017 16:03:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 26F4E28A12 for ; Tue, 3 Oct 2017 16:03:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751474AbdJCQDz (ORCPT ); Tue, 3 Oct 2017 12:03:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13604 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750787AbdJCQDy (ORCPT ); Tue, 3 Oct 2017 12:03:54 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6B594C2D0D5A; Tue, 3 Oct 2017 16:03:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 6B594C2D0D5A Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=eguan@redhat.com Received: from localhost (ovpn-12-41.pek2.redhat.com [10.72.12.41]) by smtp.corp.redhat.com (Postfix) with ESMTP id D08826266C; Tue, 3 Oct 2017 16:03:53 +0000 (UTC) From: Eryu Guan To: linux-fsdevel@vger.kernel.org Cc: linux-xfs@vger.kernel.org, Lukas Czerner , Eryu Guan Subject: [PATCH] fs: invalidate page cache after end_io() in dio completion Date: Wed, 4 Oct 2017 00:02:01 +0800 Message-Id: <20171003160201.11208-1-eguan@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Tue, 03 Oct 2017 16:03:54 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Commit 332391a9935d ("fs: Fix page cache inconsistency when mixing buffered and AIO DIO") moved page cache invalidation from iomap_dio_rw() to iomap_dio_complete() for iomap based direct write path, but before the dio->end_io() call, and it re-introdued the bug fixed by commit c771c14baa33 ("iomap: invalidate page caches should be after iomap_dio_complete() in direct write"). I found this because fstests generic/418 started failing on XFS with v4.14-rc3 kernel, which is the regression test for this specific bug. So similarly, fix it by moving dio->end_io() (which does the unwritten extent conversion) before page cache invalidation, to make sure next buffer read reads the final real allocations not unwritten extents. I also add some comments about why should end_io() go first in case we get it wrong again in the future. Note that, there's no such problem in the non-iomap based direct write path, because we didn't remove the page cache invalidation after the ->direct_IO() in generic_file_direct_write() call, but I decided to fix dio_complete() too so we don't leave a landmine there, also be consistent with iomap_dio_complete(). Fixes: 332391a9935d ("fs: Fix page cache inconsistency when mixing buffered and AIO DIO") Signed-off-by: Eryu Guan Reviewed-by: Jan Kara Reviewed-by: Lukas Czerner Reviewed-by: Darrick J. Wong --- fs/direct-io.c | 20 ++++++++++++-------- fs/iomap.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 36 insertions(+), 25 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index 62cf812ed0e5..1dba6842c349 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -259,12 +259,24 @@ static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async) if (ret == 0) ret = transferred; + if (dio->end_io) { + // XXX: ki_pos?? + err = dio->end_io(dio->iocb, offset, ret, dio->private); + if (err) + ret = err; + } + /* * Try again to invalidate clean pages which might have been cached by * non-direct readahead, or faulted in by get_user_pages() if the source * of the write was an mmap'ed region of the file we're writing. Either * one is a pretty crazy thing to do, so we don't support it 100%. If * this invalidation fails, tough, the write still worked... + * + * And this page cache invalidation has to be after dio->end_io(), as + * some filesystems convert unwritten extents to real allocations in + * end_io() when necessary, otherwise a racing buffer read would cache + * zeros from unwritten extents. */ if (ret > 0 && dio->op == REQ_OP_WRITE && dio->inode->i_mapping->nrpages) { @@ -274,14 +286,6 @@ static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async) WARN_ON_ONCE(err); } - if (dio->end_io) { - - // XXX: ki_pos?? - err = dio->end_io(dio->iocb, offset, ret, dio->private); - if (err) - ret = err; - } - if (!(dio->flags & DIO_SKIP_DIO_COUNT)) inode_dio_end(dio->inode); diff --git a/fs/iomap.c b/fs/iomap.c index be61cf742b5e..d4801f8dd4fd 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -714,23 +714,9 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) { struct kiocb *iocb = dio->iocb; struct inode *inode = file_inode(iocb->ki_filp); + loff_t offset = iocb->ki_pos; ssize_t ret; - /* - * Try again to invalidate clean pages which might have been cached by - * non-direct readahead, or faulted in by get_user_pages() if the source - * of the write was an mmap'ed region of the file we're writing. Either - * one is a pretty crazy thing to do, so we don't support it 100%. If - * this invalidation fails, tough, the write still worked... - */ - if (!dio->error && - (dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) { - ret = invalidate_inode_pages2_range(inode->i_mapping, - iocb->ki_pos >> PAGE_SHIFT, - (iocb->ki_pos + dio->size - 1) >> PAGE_SHIFT); - WARN_ON_ONCE(ret); - } - if (dio->end_io) { ret = dio->end_io(iocb, dio->error ? dio->error : dio->size, @@ -742,12 +728,33 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) if (likely(!ret)) { ret = dio->size; /* check for short read */ - if (iocb->ki_pos + ret > dio->i_size && + if (offset + ret > dio->i_size && !(dio->flags & IOMAP_DIO_WRITE)) - ret = dio->i_size - iocb->ki_pos; + ret = dio->i_size - offset; iocb->ki_pos += ret; } + /* + * Try again to invalidate clean pages which might have been cached by + * non-direct readahead, or faulted in by get_user_pages() if the source + * of the write was an mmap'ed region of the file we're writing. Either + * one is a pretty crazy thing to do, so we don't support it 100%. If + * this invalidation fails, tough, the write still worked... + * + * And this page cache invalidation has to be after dio->end_io(), as + * some filesystems convert unwritten extents to real allocations in + * end_io() when necessary, otherwise a racing buffer read would cache + * zeros from unwritten extents. + */ + if (!dio->error && + (dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) { + int err; + err = invalidate_inode_pages2_range(inode->i_mapping, + offset >> PAGE_SHIFT, + (offset + dio->size - 1) >> PAGE_SHIFT); + WARN_ON_ONCE(err); + } + inode_dio_end(file_inode(iocb->ki_filp)); kfree(dio);