From patchwork Tue Nov 1 07:43:07 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eryu Guan X-Patchwork-Id: 9407035 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 564B760585 for ; Tue, 1 Nov 2016 07:44:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3A98E29587 for ; Tue, 1 Nov 2016 07:44:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2BA90295AC; Tue, 1 Nov 2016 07:44:05 +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=-6.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham 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 4865A29587 for ; Tue, 1 Nov 2016 07:44:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1034751AbcKAHn7 (ORCPT ); Tue, 1 Nov 2016 03:43:59 -0400 Received: from mail-pf0-f196.google.com ([209.85.192.196]:35377 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1034733AbcKAHn6 (ORCPT ); Tue, 1 Nov 2016 03:43:58 -0400 Received: by mail-pf0-f196.google.com with SMTP id s8so10956309pfj.2; Tue, 01 Nov 2016 00:43:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=FRVSfSKv/3eRG7NT6GDEDwjuLnd2OUc48XCoTkqVcyE=; b=f/mQBpuFx2EWPKa6NiYHs67BtCmOa3W9draUIqJT62BNObIkVOgd7lYMl513rh7aDW ++3yA8SllkGnDQPl8EsU9kPHwPWF6fMKSVAhf5D40mKToKGPXkBKr++EkAdR2K5Vfzc1 dVM2+Ckpe58+9N2Cb0PPHPj/JqW352LIqT5UNwXWALC5vaQWJqvPlapBnw7SWAtLAABp LtEJK8vp1TnQccik9DggbhGeWHoJ4ikXsJaFM8Aem8ZesyIgfQe4xagmq3EFyo+GMIMb ggMstBjkdk8GR2fG6umAAbyHvSDUrKpWH07LfCFatqnP6IgrUzuuIW9jGnxXsZ2iAhSl 9OTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=FRVSfSKv/3eRG7NT6GDEDwjuLnd2OUc48XCoTkqVcyE=; b=aw/wOssUiA/qwCzl4S1wt+86P/BDrn02BpJTleZIfsf4Cr7QL8ijGIm6vxyvEKw7r6 rC3O/TWiHUQTLgBsthf2w8/IDEcX7FD5hjGwezNwilEBaVVdbGTB9UajVFSZdstrcUD1 rb6+ylUYmceG4u7/96zyx4tG6e3L4w2BcwB/EIA1djFJ3Hq6pEyDncPK+OrNYdZknuNA NZajo3WWKO1tFsYUfgHh5s/5YkIVq1balpJbNodyEI72UOIMboXjCOStsr7ztY15CHii d1d9pTwc+t8b2PC3yzkW1vgjdBx7ibzgQG8cVEMzw3rAgmnON1l09qSAxyZZOvzyzcu5 T1Yg== X-Gm-Message-State: ABUngvc0BhzSx49//fD2gZ4jlzrgl+eAjm5yLjnOqZwIghFgVLIRPa5vppM4dE8CztC9Yw== X-Received: by 10.98.0.198 with SMTP id 189mr58195650pfa.75.1477986237355; Tue, 01 Nov 2016 00:43:57 -0700 (PDT) Received: from localhost ([128.199.137.77]) by smtp.gmail.com with ESMTPSA id w15sm40073901pfi.55.2016.11.01.00.43.56 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 01 Nov 2016 00:43:56 -0700 (PDT) From: Eryu Guan To: akpm@linux-foundation.org, linux-mm@kvack.org Cc: viro@zeniv.linux.org.uk, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Eryu Guan Subject: [PATCH v2] mm/filemap: don't allow partially uptodate page for pipes Date: Tue, 1 Nov 2016 15:43:07 +0800 Message-Id: <1477986187-12717-1-git-send-email-guaneryu@gmail.com> X-Mailer: git-send-email 2.7.4 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 Starting from 4.9-rc1 kernel, I started noticing some test failures of sendfile(2) and splice(2) (sendfile0N and splice01 from LTP) when testing on sub-page block size filesystems (tested both XFS and ext4), these syscalls start to return EIO in the tests. e.g. sendfile02 1 TFAIL : sendfile02.c:133: sendfile(2) failed to return expected value, expected: 26, got: -1 sendfile02 2 TFAIL : sendfile02.c:133: sendfile(2) failed to return expected value, expected: 24, got: -1 sendfile02 3 TFAIL : sendfile02.c:133: sendfile(2) failed to return expected value, expected: 22, got: -1 sendfile02 4 TFAIL : sendfile02.c:133: sendfile(2) failed to return expected value, expected: 20, got: -1 This is because that in sub-page block size cases, we don't need the whole page to be uptodate, only the part we care about is uptodate is OK (if fs has ->is_partially_uptodate defined). But page_cache_pipe_buf_confirm() doesn't have the ability to check the partially-uptodate case, it needs the whole page to be uptodate. So it returns EIO in this case. This is a regression introduced by commit 82c156f85384 ("switch generic_file_splice_read() to use of ->read_iter()"). Prior to the change, generic_file_splice_read() doesn't allow partially-uptodate page either, so it worked fine. Fix it by skipping the partially-uptodate check if we're working on a pipe in do_generic_file_read(), so we read the whole page from disk as long as the page is not uptodate. Signed-off-by: Eryu Guan Reviewed-by: Jan Kara --- I think the other way to fix it is to add the ability to check & allow partially-uptodate page to page_cache_pipe_buf_confirm(), but that is much harder to do and seems gain little. v2: - Update summary a little bit - Update commit log - Add comment to the code - Add more people/list to cc v1: http://marc.info/?l=linux-mm&m=147756897431777&w=2 mm/filemap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/filemap.c b/mm/filemap.c index 849f459..670264d 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1734,6 +1734,9 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos, if (inode->i_blkbits == PAGE_SHIFT || !mapping->a_ops->is_partially_uptodate) goto page_not_up_to_date; + /* pipes can't handle partially uptodate pages */ + if (unlikely(iter->type & ITER_PIPE)) + goto page_not_up_to_date; if (!trylock_page(page)) goto page_not_up_to_date; /* Did it get truncated before we got the lock? */