From patchwork Wed Aug 24 09:34:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Wysochanski X-Patchwork-Id: 12953099 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BE2DC38142 for ; Wed, 24 Aug 2022 09:35:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235463AbiHXJfN (ORCPT ); Wed, 24 Aug 2022 05:35:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235680AbiHXJfL (ORCPT ); Wed, 24 Aug 2022 05:35:11 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1493076443 for ; Wed, 24 Aug 2022 02:35:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1661333709; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=svgx48O+sZiHrg49Ikl8xp1SYbrgYFheSwSNP4x6DZI=; b=ggO9rdGPEutrDCTOVNkBd9lE8nECeK+J+xChBz0e3TRQcXLCSs0+AJtoLYCnKOd4/W+isW pOR6oOALU35wJZUTqQ1Y1HBFM1oa5ORGC7wwyealdiJSR3R5u5a6WiX7FPI60x/aUnVA2F GB+16JFYhuv/t9SRCV18dOT3b33f8Ak= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-522-Tb0UZZv_OIG1CiPcDC0EGQ-1; Wed, 24 Aug 2022 05:35:04 -0400 X-MC-Unique: Tb0UZZv_OIG1CiPcDC0EGQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9FDF685A585; Wed, 24 Aug 2022 09:35:03 +0000 (UTC) Received: from dwysocha.rdu.csb (unknown [10.22.8.98]) by smtp.corp.redhat.com (Postfix) with ESMTPS id ED36314152E0; Wed, 24 Aug 2022 09:35:02 +0000 (UTC) From: Dave Wysochanski To: Anna Schumaker , Trond Myklebust , David Howells Cc: linux-nfs@vger.kernel.org, linux-cachefs@redhat.com, Benjamin Maynard , Daire Byrne Subject: [RFC PATCH 0/3] Convert NFS to the new netfs API Date: Wed, 24 Aug 2022 05:34:58 -0400 Message-Id: <20220824093501.384755-1-dwysocha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org This patchset converts NFS non-direct READ IO paths to unconditionally use the netfs API with a non-invasive approach. The existing NFS pgio layer does not need extensive changes, and is the best way so far I've found to avoid Trond's earlier objection [1]. I have not yet attempted performance comparisions to address Chuck Lever's concern [2]. The main patch to be reviewed is patch #3 which converts nfs_read_folio and nfs_readahead. I do not really like this patchset but so far this is what I was able to come up with the move things forward. I think it is awkward and still needs work, has some issues (below) though it is fairly stable by running xfstests generic with various servers. The known issues are as follows: 1. Unit test setting rsize < readahead does not properly read from fscache but re-reads data from the NFS server * This will be fixed once another linux-cachefs [3] patch to resolve "Stop read optimisation when folio removed from pagecache" 2. "Cache volume key already in use" after xfstest runs * xfstests (hammerspace with vers=4.2,fsc) shows the following on the console after some tests: "NFS: Cache volume key already in use (nfs,4.1,2,c50,cfe0100a,3,,,8000,100000,100000,bb8,ea60,7530,ea60,1)" * This may be fixed with another patch [4] that is in progress 3. Occasional process IO hangs in read paths * May be due to out-of-order RPC replies or something unique to NetApp triggering a bug in the conversion patch * xfstests (Example: generic/075 with netapp ontap9 vers=4.1) * Sample backtrace #2 [ffff888104967990] io_schedule at ffffffffbc46969d #3 [ffff8881049679b0] folio_wait_bit_common at ffffffffbb40214b #4 [ffff888104967ad0] filemap_get_pages at ffffffffbb40688c #5 [ffff888104967c00] filemap_read at ffffffffbb406a61 #6 [ffff888104967d80] nfs_file_read at ffffffffc0e0f415 [nfs] #7 [ffff888104967db0] vfs_read at ffffffffbb5681a5 4. Data corruption seen with unit test where rsize < readahead * Seen with vanilla 6.0-rc2 (did not occur on 5.19); likely unrelated to this patchset mount -o vers=4.2,fsc,rsize=8192 127.0.0.1:/export /mnt dd if=/dev/urandom of=/tmp/integrity-rsize-file1.bin bs=16k count=1 ./nfs-readahead.sh set /mnt 16384 dd if=/tmp/integrity-rsize-file1.bin of=/mnt/integrity-rsize-file1.bin bs=16k count=1 echo 3 > /proc/sys/vm/drop_caches md5sum /mnt/integrity-rsize-file1.bin /tmp/integrity-rsize-file1.bin md5sums don't match, MD5_NFS = 00eaf1a5bc1b3dfd54711db551619afa != MD5_LOCAL = e8d835c83ba1f1264869dc40673fa20c The patchset is based on 6.0-rc2 and has been pushed to github at: https://github.com/DaveWysochanskiRH/kernel/commits/nfs-fscache-netfs [1] https://lore.kernel.org/linux-nfs/9cfd5bc3cfc6abc2d3316b0387222e708d67f595.camel@hammerspace.com/ [2] https://marc.info/?l=linux-nfs&m=160597917525083&w=4 [3] https://www.mail-archive.com/linux-cachefs@redhat.com/msg03043.html [4] https://marc.info/?l=linux-nfs&m=165962662200679&w=4 Dave Wysochanski (3): NFS: Rename readpage_async_filler to nfs_pageio_add_page NFS: Add support for netfs in struct nfs_inode and Kconfig NFS: Convert nfs_read_folio and nfs_readahead to netfs APIs fs/nfs/Kconfig | 1 + fs/nfs/delegation.c | 2 +- fs/nfs/dir.c | 2 +- fs/nfs/fscache.c | 191 ++++++++++++++++++--------------------- fs/nfs/fscache.h | 77 ++++++++-------- fs/nfs/inode.c | 8 +- fs/nfs/internal.h | 10 +- fs/nfs/pagelist.c | 14 +++ fs/nfs/pnfs.c | 12 +-- fs/nfs/read.c | 117 ++++++++---------------- fs/nfs/write.c | 2 +- include/linux/nfs_fs.h | 19 +--- include/linux/nfs_page.h | 1 + include/linux/nfs_xdr.h | 1 + 14 files changed, 210 insertions(+), 247 deletions(-)