From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2DAAD8289E; Mon, 15 Apr 2024 12:49:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713185383; cv=none; b=CbLMjVrXeuIPCUSZh9yieB8g15Iq3C9CwBM9rG+7IkHQFvpxPe2oGF6Z+Vvtyr4xCl1SuDwkc0HWs6kuOrrQRF6oMruJfrLrpo1aCrboNfnm6yTorpro9FsL4AZblwmT/+8CVyMJMBGUJN+YI+38x9cqHIVudMrRww/58ifOcg4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713185383; c=relaxed/simple; bh=A4QhcND1ZpufPBx/famSbhUuWoIfXwb4BwDvzp25qAE=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=ZnRI6T47+cUaOH7V6wzP6lcRNK9WisW8gw99IlyT0MjMpBi9RSs1c+7eM8OAwzrLVle1HuEgTg5xxQrLbAYReVtaIfSrCZcmZQ0eBBVe59xFpzsrWHvZ89e6MfxxZUuKsW4WYO4mM5k2frqXXO9uW4JEKUbP5IpnXBGKKPRiIf0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PGqjMFzH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PGqjMFzH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B86D1C2BD11; Mon, 15 Apr 2024 12:49:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713185382; bh=A4QhcND1ZpufPBx/famSbhUuWoIfXwb4BwDvzp25qAE=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=PGqjMFzH68ZJY3XlVsWUcKaHmR7w+9vctik141QhIl9Li7zHE+dvpfrUvnbdNdKDt mgd/ZO98G0exwiFgfJbjMsWtdjOnYn4TgrrRcN3byBti56dNRvyTMLL1O6jZvFP8SF OMdledu7PfctzeZov12oyg5oFMC62r3VcZyVA/dxE0MXj1I8VWYlRmFRsjbFn4zV58 qyGUngLzfNzU1VyLjeKR3ZrEjqz2FPQL7dhOi1+sZDWhq+lOQhkj49NpXRIW7jteMz LSRW4JvOCEmWOJcbLdT+na9XnS/gXvBNPHdmokI9BMdCvdC+J9n+ZIyS47bkpxDd6Q SjQFHSDJFHM4A== Message-ID: <5c905e500499a07c5e4b0dcf9983b90e8746ed81.camel@kernel.org> Subject: Re: [PATCH 00/26] netfs, afs, 9p, cifs: Rework netfs to use ->writepages() to copy to cache From: Jeff Layton To: David Howells , Christian Brauner , Gao Xiang , Dominique Martinet Cc: Matthew Wilcox , Steve French , Marc Dionne , Paulo Alcantara , Shyam Prasad N , Tom Talpey , Eric Van Hensbergen , Ilya Dryomov , netfs@lists.linux.dev, linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs@lists.linux.dev, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Date: Mon, 15 Apr 2024 08:49:39 -0400 In-Reply-To: <20240328163424.2781320-1-dhowells@redhat.com> References: <20240328163424.2781320-1-dhowells@redhat.com> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=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 3bri75n1TkBYGmqAXy9usCkHIsG5CBHmphv9MHmqMZQVsxvCzfnI5IO1+7MoloeeW/lxuyd0pU88dZsV/riHw87i2GJUJtVlMl5IGBNFpqoNUoqmvRfEMeXhy/kUX4Xc03I1coZIgmwLmCSXwx9MaCPFzV/dOOrju2xjO+2sYyB5BNtxRqUEyXglpujFZqJxxau7E0eXoYgoY9gtFGsspzFkVNntamVXEWVVgzJJr/EWW0y+jNd54MfPRqH+eCGuqlnNLktSAVz1MvVRY1dxUltSlDZT7P2bUoMorIPu8p7ZCg9dyX1+9T6Muc5dHxf/BBP/ir+3e8JTFQBFOiLNdFtB9KZWZmIExheXRvbiA8amxheXRvbkBzYW1iYS5vcmc+iQI4BBMBAgAiBQJOldK9AhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRAADmhBGVaCFWgWD/0ZRi4hN9FK2BdQs9RwNnFZUr7JidAWfCrs37XrA/56olQl3ojn0fQtrP4DbTmCuh0SfMijB24psy1GnkPepnaQ6VRf7Dxg/Y8muZELSOtsv2CKt3/02J1BBitrkkqmHyni5fLLYYg6fub0T/8Kwo1qGPdu1hx2BQRERYtQ/S5d/T0cACdlzi6w8rs5f09hU9Tu4qV1JLKmBTgUWKN969HPRkxiojLQziHVyM/weR5Reu6FZVNuVBGqBD+sfk/c98VJHjsQhYJijcsmgMb1NohAzwrBKcSGKOWJToGEO/1RkIN8tqGnYNp2G+aR685D0chgTl1WzPRM6mFG1+n2b2RR95DxumKVpwBwdLPoCkI24JkeDJ7lXSe3uFWISstFGt0HL8EewP8RuGC8s5h7Ct91HMNQTbjgA+Vi1foWUVXpEintAKgoywaIDlJfTZIl6Ew8ETN/7DLy8bXYgq0XzhaKg3CnOUuGQV5/nl4OAX/3jocT5Cz/OtAiNYj5mLPeL5z2ZszjoCAH6caqsF2oLyA 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 kZWuOsJdJQdmwlWC5L5ln9xgfr/4mOY38B0U= Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.4 (3.50.4-1.fc39) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2024-03-28 at 16:33 +0000, David Howells wrote: > Hi Christian, Willy, >=20 > The primary purpose of these patches is to rework the netfslib writeback > implementation such that pages read from the cache are written to the cac= he > through ->writepages(), thereby allowing the fscache page flag to be > retired. >=20 > The reworking also: >=20 > (1) builds on top of the new writeback_iter() infrastructure; >=20 > (2) makes it possible to use vectored write RPCs as discontiguous stream= s > of pages can be accommodated; >=20 > (3) makes it easier to do simultaneous content crypto and stream divisio= n. >=20 > (4) provides support for retrying writes and re-dividing a stream; >=20 > (5) replaces the ->launder_folio() op, so that ->writepages() is used > instead; >=20 > (6) uses mempools to allocate the netfs_io_request and netfs_io_subreque= st > structs to avoid allocation failure in the writeback path. >=20 > Some code that uses the fscache page flag is retained for compatibility > purposes with nfs and ceph. The code is switched to using the synonymous > private_2 label instead and marked with deprecation comments. I have a > separate set of patches that convert cifs to use this code. >=20 > -~- >=20 > In this new implementation, writeback_iter() is used to pump folios, > progressively creating two parallel, but separate streams. Either or bot= h > streams can contain gaps, and the subrequests in each stream can be of > variable size, don't need to align with each other and don't need to alig= n > with the folios. (Note that more streams can be added if we have multipl= e > servers to duplicate data to). >=20 > Indeed, subrequests can cross folio boundaries, may cover several folios = or > a folio may be spanned by multiple subrequests, e.g.: >=20 > +---+---+-----+-----+---+----------+ > Folios: | | | | | | | > +---+---+-----+-----+---+----------+ >=20 > +------+------+ +----+----+ > Upload: | | |.....| | | > +------+------+ +----+----+ >=20 > +------+------+------+------+------+ > Cache: | | | | | | > +------+------+------+------+------+ >=20 > Data that got read from the server that needs copying to the cache is > stored in folios that are marked dirty and have folio->private set to a > special value. >=20 > The progressive subrequest construction permits the algorithm to be > preparing both the next upload to the server and the next write to the > cache whilst the previous ones are already in progress. Throttling can b= e > applied to control the rate of production of subrequests - and, in any > case, we probably want to write them to the server in ascending order, > particularly if the file will be extended. >=20 > Content crypto can also be prepared at the same time as the subrequests a= nd > run asynchronously, with the prepped requests being stalled until the > crypto catches up with them. This might also be useful for transport > crypto, but that happens at a lower layer, so probably would be harder to > pull off. >=20 > The algorithm is split into three parts: >=20 > (1) The issuer. This walks through the data, packaging it up, encryptin= g > it and creating subrequests. The part of this that generates > subrequests only deals with file positions and spans and so is usabl= e > for DIO/unbuffered writes as well as buffered writes. >=20 > (2) The collector. This asynchronously collects completed subrequests, > unlocks folios, frees crypto buffers and performs any retries. This > runs in a work queue so that the issuer can return to the caller for > writeback (so that the VM can have its kswapd thread back) or async > writes. >=20 > Collection is slightly complex as the collector has to work out wher= e > discontiguities happen in the folio list so that it doesn't try and > collect folios that weren't included in the write out. >=20 > (3) The retryer. This pauses the issuer, waits for all outstanding > subrequests to complete and then goes through the failed subrequests > to reissue them. This may involve reprepping them (with cifs, the > credits must be renegotiated and a subrequest may need splitting), a= nd > doing RMW for content crypto if there's a conflicting change on the > server. >=20 > David >=20 > David Howells (26): > cifs: Fix duplicate fscache cookie warnings > 9p: Clean up some kdoc and unused var warnings. > netfs: Update i_blocks when write committed to pagecache > netfs: Replace PG_fscache by setting folio->private and marking dirty > mm: Remove the PG_fscache alias for PG_private_2 > netfs: Remove deprecated use of PG_private_2 as a second writeback > flag > netfs: Make netfs_io_request::subreq_counter an atomic_t > netfs: Use subreq_counter to allocate subreq debug_index values > mm: Provide a means of invalidation without using launder_folio > cifs: Use alternative invalidation to using launder_folio > 9p: Use alternative invalidation to using launder_folio > afs: Use alternative invalidation to using launder_folio > netfs: Remove ->launder_folio() support > netfs: Use mempools for allocating requests and subrequests > mm: Export writeback_iter() > netfs: Switch to using unsigned long long rather than loff_t > netfs: Fix writethrough-mode error handling > netfs: Add some write-side stats and clean up some stat names > netfs: New writeback implementation > netfs, afs: Implement helpers for new write code > netfs, 9p: Implement helpers for new write code > netfs, cachefiles: Implement helpers for new write code > netfs: Cut over to using new writeback code > netfs: Remove the old writeback code > netfs: Miscellaneous tidy ups > netfs, afs: Use writeback retry to deal with alternate keys >=20 > fs/9p/vfs_addr.c | 60 +-- > fs/9p/vfs_inode_dotl.c | 4 - > fs/afs/file.c | 8 +- > fs/afs/internal.h | 6 +- > fs/afs/validation.c | 4 +- > fs/afs/write.c | 187 ++++---- > fs/cachefiles/io.c | 75 +++- > fs/ceph/addr.c | 24 +- > fs/ceph/inode.c | 2 + > fs/netfs/Makefile | 3 +- > fs/netfs/buffered_read.c | 40 +- > fs/netfs/buffered_write.c | 832 ++++------------------------------- > fs/netfs/direct_write.c | 30 +- > fs/netfs/fscache_io.c | 14 +- > fs/netfs/internal.h | 55 ++- > fs/netfs/io.c | 155 +------ > fs/netfs/main.c | 55 ++- > fs/netfs/misc.c | 10 +- > fs/netfs/objects.c | 81 +++- > fs/netfs/output.c | 478 -------------------- > fs/netfs/stats.c | 17 +- > fs/netfs/write_collect.c | 813 ++++++++++++++++++++++++++++++++++ > fs/netfs/write_issue.c | 673 ++++++++++++++++++++++++++++ > fs/nfs/file.c | 8 +- > fs/nfs/fscache.h | 6 +- > fs/nfs/write.c | 4 +- > fs/smb/client/cifsfs.h | 1 - > fs/smb/client/file.c | 136 +----- > fs/smb/client/fscache.c | 16 +- > fs/smb/client/inode.c | 27 +- > include/linux/fscache.h | 22 +- > include/linux/netfs.h | 196 +++++---- > include/linux/pagemap.h | 1 + > include/net/9p/client.h | 2 + > include/trace/events/netfs.h | 249 ++++++++++- > mm/filemap.c | 52 ++- > mm/page-writeback.c | 1 + > net/9p/Kconfig | 1 + > net/9p/client.c | 49 +++ > net/9p/trans_fd.c | 1 - > 40 files changed, 2492 insertions(+), 1906 deletions(-) > delete mode 100644 fs/netfs/output.c > create mode 100644 fs/netfs/write_collect.c > create mode 100644 fs/netfs/write_issue.c >=20 This all looks pretty reasonable. There is at least one bugfix that looks like it ought to go in independently (#17). #19 is huge, complex and hard to review. That will need some cycles in -next, I think. In any case, on any that I didn't send comments you can add: Reviewed-by: Jeff Layton From mboxrd@z Thu Jan 1 00:00:00 1970 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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B66F7C00A94 for ; Mon, 15 Apr 2024 12:49:51 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=PGqjMFzH; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4VJ6St39n5z3dWh for ; Mon, 15 Apr 2024 22:49:50 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=PGqjMFzH; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:40e1:4800::1; helo=sin.source.kernel.org; envelope-from=jlayton@kernel.org; receiver=lists.ozlabs.org) Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4VJ6Sn0bkQz2xmC for ; Mon, 15 Apr 2024 22:49:45 +1000 (AEST) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 8AA39CE0B11; Mon, 15 Apr 2024 12:49:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B86D1C2BD11; Mon, 15 Apr 2024 12:49:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713185382; bh=A4QhcND1ZpufPBx/famSbhUuWoIfXwb4BwDvzp25qAE=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=PGqjMFzH68ZJY3XlVsWUcKaHmR7w+9vctik141QhIl9Li7zHE+dvpfrUvnbdNdKDt mgd/ZO98G0exwiFgfJbjMsWtdjOnYn4TgrrRcN3byBti56dNRvyTMLL1O6jZvFP8SF OMdledu7PfctzeZov12oyg5oFMC62r3VcZyVA/dxE0MXj1I8VWYlRmFRsjbFn4zV58 qyGUngLzfNzU1VyLjeKR3ZrEjqz2FPQL7dhOi1+sZDWhq+lOQhkj49NpXRIW7jteMz LSRW4JvOCEmWOJcbLdT+na9XnS/gXvBNPHdmokI9BMdCvdC+J9n+ZIyS47bkpxDd6Q SjQFHSDJFHM4A== Message-ID: <5c905e500499a07c5e4b0dcf9983b90e8746ed81.camel@kernel.org> Subject: Re: [PATCH 00/26] netfs, afs, 9p, cifs: Rework netfs to use ->writepages() to copy to cache From: Jeff Layton To: David Howells , Christian Brauner , Gao Xiang , Dominique Martinet Date: Mon, 15 Apr 2024 08:49:39 -0400 In-Reply-To: <20240328163424.2781320-1-dhowells@redhat.com> References: <20240328163424.2781320-1-dhowells@redhat.com> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=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 kZWuOsJdJQdmwlWC5L5ln9xgfr/4mOY38B0U= Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.4 (3.50.4-1.fc39) MIME-Version: 1.0 X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paulo Alcantara , linux-cifs@vger.kernel.org, Shyam Prasad N , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, v9fs@lists.linux.dev, ceph-devel@vger.kernel.org, linux-nfs@vger.kernel.org, Matthew Wilcox , linux-kernel@vger.kernel.org, Tom Talpey , Steve French , linux-cachefs@redhat.com, netdev@vger.kernel.org, Marc Dionne , netfs@lists.linux.dev, Ilya Dryomov , Eric Van Hensbergen , linux-erofs@lists.ozlabs.org, linux-afs@lists.infradead.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" On Thu, 2024-03-28 at 16:33 +0000, David Howells wrote: > Hi Christian, Willy, >=20 > The primary purpose of these patches is to rework the netfslib writeback > implementation such that pages read from the cache are written to the cac= he > through ->writepages(), thereby allowing the fscache page flag to be > retired. >=20 > The reworking also: >=20 > (1) builds on top of the new writeback_iter() infrastructure; >=20 > (2) makes it possible to use vectored write RPCs as discontiguous stream= s > of pages can be accommodated; >=20 > (3) makes it easier to do simultaneous content crypto and stream divisio= n. >=20 > (4) provides support for retrying writes and re-dividing a stream; >=20 > (5) replaces the ->launder_folio() op, so that ->writepages() is used > instead; >=20 > (6) uses mempools to allocate the netfs_io_request and netfs_io_subreque= st > structs to avoid allocation failure in the writeback path. >=20 > Some code that uses the fscache page flag is retained for compatibility > purposes with nfs and ceph. The code is switched to using the synonymous > private_2 label instead and marked with deprecation comments. I have a > separate set of patches that convert cifs to use this code. >=20 > -~- >=20 > In this new implementation, writeback_iter() is used to pump folios, > progressively creating two parallel, but separate streams. Either or bot= h > streams can contain gaps, and the subrequests in each stream can be of > variable size, don't need to align with each other and don't need to alig= n > with the folios. (Note that more streams can be added if we have multipl= e > servers to duplicate data to). >=20 > Indeed, subrequests can cross folio boundaries, may cover several folios = or > a folio may be spanned by multiple subrequests, e.g.: >=20 > +---+---+-----+-----+---+----------+ > Folios: | | | | | | | > +---+---+-----+-----+---+----------+ >=20 > +------+------+ +----+----+ > Upload: | | |.....| | | > +------+------+ +----+----+ >=20 > +------+------+------+------+------+ > Cache: | | | | | | > +------+------+------+------+------+ >=20 > Data that got read from the server that needs copying to the cache is > stored in folios that are marked dirty and have folio->private set to a > special value. >=20 > The progressive subrequest construction permits the algorithm to be > preparing both the next upload to the server and the next write to the > cache whilst the previous ones are already in progress. Throttling can b= e > applied to control the rate of production of subrequests - and, in any > case, we probably want to write them to the server in ascending order, > particularly if the file will be extended. >=20 > Content crypto can also be prepared at the same time as the subrequests a= nd > run asynchronously, with the prepped requests being stalled until the > crypto catches up with them. This might also be useful for transport > crypto, but that happens at a lower layer, so probably would be harder to > pull off. >=20 > The algorithm is split into three parts: >=20 > (1) The issuer. This walks through the data, packaging it up, encryptin= g > it and creating subrequests. The part of this that generates > subrequests only deals with file positions and spans and so is usabl= e > for DIO/unbuffered writes as well as buffered writes. >=20 > (2) The collector. This asynchronously collects completed subrequests, > unlocks folios, frees crypto buffers and performs any retries. This > runs in a work queue so that the issuer can return to the caller for > writeback (so that the VM can have its kswapd thread back) or async > writes. >=20 > Collection is slightly complex as the collector has to work out wher= e > discontiguities happen in the folio list so that it doesn't try and > collect folios that weren't included in the write out. >=20 > (3) The retryer. This pauses the issuer, waits for all outstanding > subrequests to complete and then goes through the failed subrequests > to reissue them. This may involve reprepping them (with cifs, the > credits must be renegotiated and a subrequest may need splitting), a= nd > doing RMW for content crypto if there's a conflicting change on the > server. >=20 > David >=20 > David Howells (26): > cifs: Fix duplicate fscache cookie warnings > 9p: Clean up some kdoc and unused var warnings. > netfs: Update i_blocks when write committed to pagecache > netfs: Replace PG_fscache by setting folio->private and marking dirty > mm: Remove the PG_fscache alias for PG_private_2 > netfs: Remove deprecated use of PG_private_2 as a second writeback > flag > netfs: Make netfs_io_request::subreq_counter an atomic_t > netfs: Use subreq_counter to allocate subreq debug_index values > mm: Provide a means of invalidation without using launder_folio > cifs: Use alternative invalidation to using launder_folio > 9p: Use alternative invalidation to using launder_folio > afs: Use alternative invalidation to using launder_folio > netfs: Remove ->launder_folio() support > netfs: Use mempools for allocating requests and subrequests > mm: Export writeback_iter() > netfs: Switch to using unsigned long long rather than loff_t > netfs: Fix writethrough-mode error handling > netfs: Add some write-side stats and clean up some stat names > netfs: New writeback implementation > netfs, afs: Implement helpers for new write code > netfs, 9p: Implement helpers for new write code > netfs, cachefiles: Implement helpers for new write code > netfs: Cut over to using new writeback code > netfs: Remove the old writeback code > netfs: Miscellaneous tidy ups > netfs, afs: Use writeback retry to deal with alternate keys >=20 > fs/9p/vfs_addr.c | 60 +-- > fs/9p/vfs_inode_dotl.c | 4 - > fs/afs/file.c | 8 +- > fs/afs/internal.h | 6 +- > fs/afs/validation.c | 4 +- > fs/afs/write.c | 187 ++++---- > fs/cachefiles/io.c | 75 +++- > fs/ceph/addr.c | 24 +- > fs/ceph/inode.c | 2 + > fs/netfs/Makefile | 3 +- > fs/netfs/buffered_read.c | 40 +- > fs/netfs/buffered_write.c | 832 ++++------------------------------- > fs/netfs/direct_write.c | 30 +- > fs/netfs/fscache_io.c | 14 +- > fs/netfs/internal.h | 55 ++- > fs/netfs/io.c | 155 +------ > fs/netfs/main.c | 55 ++- > fs/netfs/misc.c | 10 +- > fs/netfs/objects.c | 81 +++- > fs/netfs/output.c | 478 -------------------- > fs/netfs/stats.c | 17 +- > fs/netfs/write_collect.c | 813 ++++++++++++++++++++++++++++++++++ > fs/netfs/write_issue.c | 673 ++++++++++++++++++++++++++++ > fs/nfs/file.c | 8 +- > fs/nfs/fscache.h | 6 +- > fs/nfs/write.c | 4 +- > fs/smb/client/cifsfs.h | 1 - > fs/smb/client/file.c | 136 +----- > fs/smb/client/fscache.c | 16 +- > fs/smb/client/inode.c | 27 +- > include/linux/fscache.h | 22 +- > include/linux/netfs.h | 196 +++++---- > include/linux/pagemap.h | 1 + > include/net/9p/client.h | 2 + > include/trace/events/netfs.h | 249 ++++++++++- > mm/filemap.c | 52 ++- > mm/page-writeback.c | 1 + > net/9p/Kconfig | 1 + > net/9p/client.c | 49 +++ > net/9p/trans_fd.c | 1 - > 40 files changed, 2492 insertions(+), 1906 deletions(-) > delete mode 100644 fs/netfs/output.c > create mode 100644 fs/netfs/write_collect.c > create mode 100644 fs/netfs/write_issue.c >=20 This all looks pretty reasonable. There is at least one bugfix that looks like it ought to go in independently (#17). #19 is huge, complex and hard to review. That will need some cycles in -next, I think. In any case, on any that I didn't send comments you can add: Reviewed-by: Jeff Layton