From patchwork Tue Nov 27 19:31:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Calum Mackay X-Patchwork-Id: 10701331 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CB67E15A7 for ; Tue, 27 Nov 2018 19:32:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BD5682C3DF for ; Tue, 27 Nov 2018 19:32:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AFEF92C3EB; Tue, 27 Nov 2018 19:32:30 +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=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI 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 372BA2C3DF for ; Tue, 27 Nov 2018 19:32:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725764AbeK1GbZ (ORCPT ); Wed, 28 Nov 2018 01:31:25 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:35072 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725752AbeK1GbZ (ORCPT ); Wed, 28 Nov 2018 01:31:25 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id wARJSjTA031316; Tue, 27 Nov 2018 19:32:25 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id; s=corp-2018-07-02; bh=9e8A80vI4q1zE/bD9DbbNeBf6azSgaLFZi44G0UtCYw=; b=jlIVi7zrem5WUVpZ6dOnurLDawGaVVp3ORKRyBgQV5WW4L1y2GWcm4DOnD7OLBZ6/jzJ tUBg5ymFE3oGhXfNoZpy95jjA61CHyky9VSMtWp+vFKOp0N/cvAyiabvBv32KisVFZwl s+Jt/jlC1oZgswLD2WQoe5QE8DHDVI65tGdXqvQ2nSRHxFK+mssq1xp9P349M8eKOCYL ZZm2CKySIvM6MFh5XOp2z8OtY5ZEoqZOd25HZn/5Cb4QZv4EC19Bs3ATV0UoQSIqRzky +fJ5+90RhwCYAFIJAcK1xjfoVscMfal7XMt/OA33ut9DX8vBzXf/4JL019ZidXSOXMeI RQ== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by aserp2120.oracle.com with ESMTP id 2nxxkqe3k8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 27 Nov 2018 19:32:25 +0000 Received: from cmackay-linux.uk.oracle.com (dhcp-10-175-169-199.vpn.oracle.com [10.175.169.199]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id wARJWKC7026540; Tue, 27 Nov 2018 19:32:22 GMT From: Calum Mackay To: trondmy@hammerspace.com, anna.schumaker@netapp.com Cc: linux-nfs@vger.kernel.org Subject: [PATCH] nfs: don't dirty kernel pages read by direct-io Date: Tue, 27 Nov 2018 19:31:30 +0000 Message-Id: <20181127193130.16593-1-calum.mackay@oracle.com> X-Mailer: git-send-email 2.9.3 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9090 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1811270166 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Dave Kleikamp When we use direct_IO with an NFS backing store, we can trigger a WARNING in __set_page_dirty(), as below, since we're dirtying the page unnecessarily in nfs_direct_read_completion(). To fix, replicate the logic in commit 53cbf3b157a0 ("fs: direct-io: don't dirtying pages for ITER_BVEC/ITER_KVEC direct read"). Other filesystems that implement direct_IO handle this; most use blockdev_direct_IO(). ceph and cifs have similar logic. mount 127.0.0.1:/export /nfs dd if=/dev/zero of=/nfs/image bs=1M count=200 losetup --direct-io=on -f /nfs/image mkfs.btrfs /dev/loop0 mount -t btrfs /dev/loop0 /mnt/ kernel: WARNING: CPU: 0 PID: 8067 at fs/buffer.c:580 __set_page_dirty+0xaf/0xd0 kernel: Modules linked in: loop(E) nfsv3(E) rpcsec_gss_krb5(E) nfsv4(E) dns_resolver(E) nfs(E) fscache(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) fuse(E) tun(E) ip6t_rpfilter(E) ipt_REJECT(E) nf_ kernel: snd_seq(E) snd_seq_device(E) snd_pcm(E) video(E) snd_timer(E) snd(E) soundcore(E) ip_tables(E) xfs(E) libcrc32c(E) sd_mod(E) sr_mod(E) cdrom(E) ata_generic(E) pata_acpi(E) crc32c_intel(E) ahci(E) li kernel: CPU: 0 PID: 8067 Comm: kworker/0:2 Tainted: G E 4.20.0-rc1.master.20181111.ol7.x86_64 #1 kernel: Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 kernel: Workqueue: nfsiod rpc_async_release [sunrpc] kernel: RIP: 0010:__set_page_dirty+0xaf/0xd0 kernel: Code: c3 48 8b 02 f6 c4 04 74 d4 48 89 df e8 ba 05 f7 ff 48 89 c6 eb cb 48 8b 43 08 a8 01 75 1f 48 89 d8 48 8b 00 a8 04 74 02 eb 87 <0f> 0b eb 83 48 83 e8 01 eb 9f 48 83 ea 01 0f 1f 00 eb 8b 48 83 e8 kernel: RSP: 0000:ffffc1c8825b7d78 EFLAGS: 00013046 kernel: RAX: 000fffffc0020089 RBX: fffff2b603308b80 RCX: 0000000000000001 kernel: RDX: 0000000000000001 RSI: ffff9d11478115c8 RDI: ffff9d11478115d0 kernel: RBP: ffffc1c8825b7da0 R08: 0000646f6973666e R09: 8080808080808080 kernel: R10: 0000000000000001 R11: 0000000000000000 R12: ffff9d11478115d0 kernel: R13: ffff9d11478115c8 R14: 0000000000003246 R15: 0000000000000001 kernel: FS: 0000000000000000(0000) GS:ffff9d115ba00000(0000) knlGS:0000000000000000 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kernel: CR2: 00007f408686f640 CR3: 0000000104d8e004 CR4: 00000000000606f0 kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 kernel: Call Trace: kernel: __set_page_dirty_buffers+0xb6/0x110 kernel: set_page_dirty+0x52/0xb0 kernel: nfs_direct_read_completion+0xc4/0x120 [nfs] kernel: nfs_pgio_release+0x10/0x20 [nfs] kernel: rpc_free_task+0x30/0x70 [sunrpc] kernel: rpc_async_release+0x12/0x20 [sunrpc] kernel: process_one_work+0x174/0x390 kernel: worker_thread+0x4f/0x3e0 kernel: kthread+0x102/0x140 kernel: ? drain_workqueue+0x130/0x130 kernel: ? kthread_stop+0x110/0x110 kernel: ret_from_fork+0x35/0x40 kernel: ---[ end trace 01341980905412c9 ]--- Signed-off-by: Dave Kleikamp Signed-off-by: Santosh Shilimkar [forward-ported to v4.20] Signed-off-by: Calum Mackay Reviewed-by: Dave Kleikamp Reviewed-by: Chuck Lever --- fs/nfs/direct.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index aa12c3063bae..33824a0a57bf 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -98,8 +98,11 @@ struct nfs_direct_req { struct pnfs_ds_commit_info ds_cinfo; /* Storage for cinfo */ struct work_struct work; int flags; + /* for write */ #define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */ #define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */ + /* for read */ +#define NFS_ODIRECT_SHOULD_DIRTY (3) /* dirty user-space page after read */ struct nfs_writeverf verf; /* unstable write verifier */ }; @@ -412,7 +415,8 @@ static void nfs_direct_read_completion(struct nfs_pgio_header *hdr) struct nfs_page *req = nfs_list_entry(hdr->pages.next); struct page *page = req->wb_page; - if (!PageCompound(page) && bytes < hdr->good_bytes) + if (!PageCompound(page) && bytes < hdr->good_bytes && + (dreq->flags == NFS_ODIRECT_SHOULD_DIRTY)) set_page_dirty(page); bytes += req->wb_bytes; nfs_list_remove_request(req); @@ -587,6 +591,9 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter) if (!is_sync_kiocb(iocb)) dreq->iocb = iocb; + if (iter_is_iovec(iter)) + dreq->flags = NFS_ODIRECT_SHOULD_DIRTY; + nfs_start_io_direct(inode); NFS_I(inode)->read_io += count;