From patchwork Mon Feb 15 15:44:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 12088545 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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 C1268C43381 for ; Mon, 15 Feb 2021 15:48:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FC2A64DE0 for ; Mon, 15 Feb 2021 15:48:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231579AbhBOPsH (ORCPT ); Mon, 15 Feb 2021 10:48:07 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:58226 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231522AbhBOPqE (ORCPT ); Mon, 15 Feb 2021 10:46:04 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613403866; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=OUcau2RScLJC1sbBhCFeWAqe5oOjO8CLqdBwSyrKW/k=; b=CPkujOIuGFUtXC/fZg6OE5tIXxwCrMswbQeLFJ76pOuwS8x1Gl8Lv8sa6rXhemy7xy6TcO u0NwCLrzGFcqiR6VWNxL53/QAxw4SPyvYbr4PwY/uIsUkV8EewjCVISsGXQjC0a9XO7aMG jzR/BliLdo7/f0aq/vhx7IWW+xz+U6g= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-357-TJr8slT8P9GEspE4LilBZQ-1; Mon, 15 Feb 2021 10:44:24 -0500 X-MC-Unique: TJr8slT8P9GEspE4LilBZQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 736BB79EC2; Mon, 15 Feb 2021 15:44:21 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-119-68.rdu2.redhat.com [10.10.119.68]) by smtp.corp.redhat.com (Postfix) with ESMTP id 38F3B608DB; Mon, 15 Feb 2021 15:44:14 +0000 (UTC) Subject: [PATCH 00/33] Network fs helper library & fscache kiocb API [ver #3] From: David Howells To: Trond Myklebust , Anna Schumaker , Steve French , Dominique Martinet Cc: linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, Jeff Layton , Matthew Wilcox , linux-cachefs@redhat.com, Alexander Viro , linux-mm@kvack.org, linux-afs@lists.infradead.org, "Matthew Wilcox (Oracle)" , v9fs-developer@lists.sourceforge.net, Christoph Hellwig , linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, Jeff Layton , Linus Torvalds , dhowells@redhat.com, Jeff Layton , David Wysochanski , "Matthew Wilcox (Oracle)" , Alexander Viro , linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Mon, 15 Feb 2021 15:44:13 +0000 Message-ID: <161340385320.1303470.2392622971006879777.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Here's a set of patches to do two things: (1) Add a helper library to handle the new VM readahead interface. This is intended to be used unconditionally by the filesystem (whether or not caching is enabled) and provides a common framework for doing caching, transparent huge pages and, in the future, possibly fscrypt and read bandwidth maximisation. It also allows the netfs and the cache to align, expand and slice up a read request from the VM in various ways; the netfs need only provide a function to read a stretch of data to the pagecache and the helper takes care of the rest. (2) Add an alternative fscache/cachfiles I/O API that uses the kiocb facility to do async DIO to transfer data to/from the netfs's pages, rather than using readpage with wait queue snooping on one side and vfs_write() on the other. It also uses less memory, since it doesn't do buffered I/O on the backing file. Note that this uses SEEK_HOLE/SEEK_DATA to locate the data available to be read from the cache. Whilst this is an improvement from the bmap interface, it still has a problem with regard to a modern extent-based filesystem inserting or removing bridging blocks of zeros. Fixing that requires a much greater overhaul. This is a step towards overhauling the fscache API. The change is opt-in on the part of the network filesystem. A netfs should not try to mix the old and the new API because of conflicting ways of handling pages and the PG_fscache page flag and because it would be mixing DIO with buffered I/O. Further, the helper library can't be used with the old API. This does not change any of the fscache cookie handling APIs or the way invalidation is done. In the near term, I intend to deprecate and remove the old I/O API (fscache_allocate_page{,s}(), fscache_read_or_alloc_page{,s}(), fscache_write_page() and fscache_uncache_page()) and eventually replace most of fscache/cachefiles with something simpler and easier to follow. The patchset contains five parts: (1) Some helper patches, including provision of an ITER_XARRAY iov iterator and a function to do readahead expansion. (2) Patches to add the netfs helper library. (3) A patch to add the fscache/cachefiles kiocb API. (4) Patches to add support in AFS for this. (5) Patches from Jeff Layton to add support in Ceph for this. Dave Wysochanski also has patches for NFS for this, though they're not included on this branch as there's an issue with PNFS. With this, AFS without a cache passes all expected xfstests; with a cache, there's an extra failure, but that's also there before these patches. Fixing that probably requires a greater overhaul. Ceph and NFS also pass the expected tests. These patches can be found also on: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=fscache-netfs-lib For diffing reference, the tag for the 9th Feb pull request is fscache-ioapi-20210203 and can be found in the same repository. Changes ======= (v3) Rolled in the bug fixes. Adjusted the functions that unlock and wait for PG_fscache according to Linus's suggestion. Hold a ref on a page when PG_fscache is set as per Linus's suggestion. Dropped NFS support and added Ceph support. (v2) Fixed some bugs and added NFS support. References ========== These patches have been published for review before, firstly as part of a larger set: Link: https://lore.kernel.org/linux-fsdevel/158861203563.340223.7585359869938129395.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/159465766378.1376105.11619976251039287525.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/159465784033.1376674.18106463693989811037.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/159465821598.1377938.2046362270225008168.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/160588455242.3465195.3214733858273019178.stgit@warthog.procyon.org.uk/ Then as a cut-down set: Link: https://lore.kernel.org/linux-fsdevel/161118128472.1232039.11746799833066425131.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/161161025063.2537118.2009249444682241405.stgit@warthog.procyon.org.uk/ Proposals/information about the design has been published here: Link: https://lore.kernel.org/lkml/24942.1573667720@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/2758811.1610621106@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/1441311.1598547738@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/160655.1611012999@warthog.procyon.org.uk/ And requests for information: Link: https://lore.kernel.org/linux-fsdevel/3326.1579019665@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/4467.1579020509@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/3577430.1579705075@warthog.procyon.org.uk/ The NFS parts, though not included here, have been tested by someone who's using fscache in production: Link: https://listman.redhat.com/archives/linux-cachefs/2020-December/msg00000.html I've posted partial patches to try and help 9p and cifs along: Link: https://lore.kernel.org/linux-fsdevel/1514086.1605697347@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-cifs/1794123.1605713481@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-fsdevel/241017.1612263863@warthog.procyon.org.uk/ Link: https://lore.kernel.org/linux-cifs/270998.1612265397@warthog.procyon.org.uk/ David --- David Howells (27): iov_iter: Add ITER_XARRAY mm: Add an unlock function for PG_private_2/PG_fscache mm: Implement readahead_control pageset expansion vfs: Export rw_verify_area() for use by cachefiles netfs: Make a netfs helper module netfs, mm: Move PG_fscache helper funcs to linux/netfs.h netfs, mm: Add unlock_page_fscache() and wait_on_page_fscache() netfs: Provide readahead and readpage netfs helpers netfs: Add tracepoints netfs: Gather stats netfs: Add write_begin helper netfs: Define an interface to talk to a cache netfs: Hold a ref on a page when PG_private_2 is set fscache, cachefiles: Add alternate API to use kiocb for read/write to cache afs: Disable use of the fscache I/O routines afs: Pass page into dirty region helpers to provide THP size afs: Print the operation debug_id when logging an unexpected data version afs: Move key to afs_read struct afs: Don't truncate iter during data fetch afs: Log remote unmarshalling errors afs: Set up the iov_iter before calling afs_extract_data() afs: Use ITER_XARRAY for writing afs: Wait on PG_fscache before modifying/releasing a page afs: Extract writeback extension into its own function afs: Prepare for use of THPs afs: Use the fs operation ops to handle FetchData completion afs: Use new fscache read helper API Jeff Layton (6): ceph: disable old fscache readpage handling ceph: rework PageFsCache handling ceph: fix fscache invalidation ceph: convert readpage to fscache read helper ceph: plug write_begin into read helper ceph: convert ceph_readpages to ceph_readahead fs/Kconfig | 1 + fs/Makefile | 1 + fs/afs/Kconfig | 1 + fs/afs/dir.c | 225 ++++--- fs/afs/file.c | 470 ++++--------- fs/afs/fs_operation.c | 4 +- fs/afs/fsclient.c | 108 +-- fs/afs/inode.c | 7 +- fs/afs/internal.h | 58 +- fs/afs/rxrpc.c | 150 ++--- fs/afs/write.c | 610 +++++++++-------- fs/afs/yfsclient.c | 82 +-- fs/cachefiles/Makefile | 1 + fs/cachefiles/interface.c | 5 +- fs/cachefiles/internal.h | 9 + fs/cachefiles/rdwr2.c | 412 ++++++++++++ fs/ceph/Kconfig | 1 + fs/ceph/addr.c | 535 ++++++--------- fs/ceph/cache.c | 125 ---- fs/ceph/cache.h | 101 +-- fs/ceph/caps.c | 10 +- fs/ceph/inode.c | 1 + fs/ceph/super.h | 1 + fs/fscache/Kconfig | 1 + fs/fscache/Makefile | 3 +- fs/fscache/internal.h | 3 + fs/fscache/page.c | 2 +- fs/fscache/page2.c | 117 ++++ fs/fscache/stats.c | 1 + fs/internal.h | 5 - fs/netfs/Kconfig | 23 + fs/netfs/Makefile | 5 + fs/netfs/internal.h | 97 +++ fs/netfs/read_helper.c | 1169 +++++++++++++++++++++++++++++++++ fs/netfs/stats.c | 59 ++ fs/read_write.c | 1 + include/linux/fs.h | 1 + include/linux/fscache-cache.h | 4 + include/linux/fscache.h | 40 +- include/linux/netfs.h | 195 ++++++ include/linux/pagemap.h | 3 + include/net/af_rxrpc.h | 2 +- include/trace/events/afs.h | 74 +-- include/trace/events/netfs.h | 201 ++++++ mm/filemap.c | 20 + mm/readahead.c | 70 ++ net/rxrpc/recvmsg.c | 9 +- 47 files changed, 3473 insertions(+), 1550 deletions(-) create mode 100644 fs/cachefiles/rdwr2.c create mode 100644 fs/fscache/page2.c create mode 100644 fs/netfs/Kconfig create mode 100644 fs/netfs/Makefile create mode 100644 fs/netfs/internal.h create mode 100644 fs/netfs/read_helper.c create mode 100644 fs/netfs/stats.c create mode 100644 include/linux/netfs.h create mode 100644 include/trace/events/netfs.h