From patchwork Sun Oct 24 13:26:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amir Goldstein X-Patchwork-Id: 12580175 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20563C433EF for ; Sun, 24 Oct 2021 13:26:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB82460F70 for ; Sun, 24 Oct 2021 13:26:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230337AbhJXN2q (ORCPT ); Sun, 24 Oct 2021 09:28:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230021AbhJXN2q (ORCPT ); Sun, 24 Oct 2021 09:28:46 -0400 Received: from mail-wr1-x42d.google.com (mail-wr1-x42d.google.com [IPv6:2a00:1450:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57D2EC061764 for ; Sun, 24 Oct 2021 06:26:25 -0700 (PDT) Received: by mail-wr1-x42d.google.com with SMTP id d13so5024004wrf.11 for ; Sun, 24 Oct 2021 06:26:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=xfSmQPTqOxoIZlSKekAsFe/BR1K85v7nZmrfNBoimgY=; b=QXnDa7+FeH2hYc1Rs3MLBDk11LG/vcNLqxEq8Jh7Tf5dKcmuf5qM/Tpo1ewTT7UfPs L/uNynvJjmtAe+v5UIMJOEOsnQWyuyrF4xAO6qO8JgO6JlqEkAO4f1y1NUCiovTleteR NW4VtretAwjY0EFeD6Ases/79U9GogMs9ZfPSRfDVcCsuQwiu0gJgo2Om7X+WRNrDdLd GR1FPp2VnMpkzUjzZuxdC1uFlkCPiXJsIMHM3FtYShfUxwAlroPDo+AMr/+dfIlpy0Ru Yx71MsDBsPfb4lx5I8Ldl8jr+S02spGyFRGOC2jdB1M3sjH06bTKNIoZMlhoVcalfvlW o4VA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=xfSmQPTqOxoIZlSKekAsFe/BR1K85v7nZmrfNBoimgY=; b=S/0RjHpp3V/p9rawvQLwJrt0v8A9soXG22O9IsfMpt6DzxvWQVCatpT6rWv4Ow/s3u HBj/kwF01YahUscamuVmvacjMZh1xXmT/GThLSpkdoN/Zc/UX5leuEkm2+tAcT6DV+d1 0dNQWb5fagWwYdo/a+aiGtMmCbPHAEGlTUmmI5O2V/ORlb9sAO1IFcUm0040j1mF5H0h uGP8FEnBitDxc6ValRTVF/Bm4ePNQYAee7gU41PNA8DWWb2+zdyAdIBfkY5uz+qzGunM jpGUCl0EglVUa5RCF+8WDIkCgo/VnwkoPgsSmUUwmmymckh9hR4oHQN53qOP3+rg0Tu0 xC4A== X-Gm-Message-State: AOAM531ekyxenbwtYBbSrx5LpyifNkug2N9LGfE4xzGXD4/sYdeHV93w ZdHN1IiL5yBLzExT4u0h2r7LB3M4oCk= X-Google-Smtp-Source: ABdhPJwTHr2ISFF++diGCZz15HDZy7qZBpbvlUZMpmlPO5Fikl5WP8B6qSnws4jkbnDIrY411KA8Ow== X-Received: by 2002:a05:6000:552:: with SMTP id b18mr16068421wrf.112.1635081983653; Sun, 24 Oct 2021 06:26:23 -0700 (PDT) Received: from localhost.localdomain ([82.114.46.186]) by smtp.gmail.com with ESMTPSA id m2sm5125449wrb.58.2021.10.24.06.26.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 24 Oct 2021 06:26:23 -0700 (PDT) From: Amir Goldstein To: Miklos Szeredi Cc: linux-fsdevel@vger.kernel.org, Miklos Szeredi Subject: [PATCH] fuse: add FOPEN_NOFLUSH Date: Sun, 24 Oct 2021 16:26:07 +0300 Message-Id: <20211024132607.1636952-1-amir73il@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Add flag returned by OPENDIR request to avoid flushing data cache on close. Different filesystems implement ->flush() is different ways: - Most disk filesystems do not implement ->flush() at all - Some network filesystem (e.g. nfs) flush local write cache of FMODE_WRITE file and send a "flush" command to server - Some network filesystem (e.g. cifs) flush local write cache of FMODE_WRITE file without sending an additional command to server FUSE flushes local write cache of ANY file, even non FMODE_WRITE and sends a "flush" command to server (if server implements it). The FUSE implementation of ->flush() seems over agressive and arbitrary and does not make a lot of sense when writeback caching is disabled. Instead of deciding on another arbitrary implementation that makes sense, leave the choice of per-file flush behavior in the hands of the server. Link: https://lore.kernel.org/linux-fsdevel/CAJfpegspE8e6aKd47uZtSYX8Y-1e1FWS0VL0DH2Skb9gQP5RJQ@mail.gmail.com/ Suggested-by: Miklos Szeredi Signed-off-by: Amir Goldstein --- Hi Miklos, I've tested this manually by watching --debug-fuse prints with and without --nocache option to passthrough_hp. The libfuse+passthrough_hp patch is at: https://github.com/amir73il/libfuse/commits/fopen_noflush Thanks, Amir. fs/fuse/file.c | 3 +++ include/uapi/linux/fuse.h | 3 +++ 2 files changed, 6 insertions(+) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 11404f8c21c7..6f502a76f9ac 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -483,6 +483,9 @@ static int fuse_flush(struct file *file, fl_owner_t id) if (fuse_is_bad(inode)) return -EIO; + if (ff->open_flags & FOPEN_NOFLUSH) + return 0; + err = write_inode_now(inode, 1); if (err) return err; diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index 36ed092227fa..383781d1878f 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -184,6 +184,7 @@ * * 7.34 * - add FUSE_SYNCFS + * - add FOPEN_NOFLUSH */ #ifndef _LINUX_FUSE_H @@ -290,12 +291,14 @@ struct fuse_file_lock { * FOPEN_NONSEEKABLE: the file is not seekable * FOPEN_CACHE_DIR: allow caching this directory * FOPEN_STREAM: the file is stream-like (no file position at all) + * FOPEN_NOFLUSH: don't flush data cache on every close */ #define FOPEN_DIRECT_IO (1 << 0) #define FOPEN_KEEP_CACHE (1 << 1) #define FOPEN_NONSEEKABLE (1 << 2) #define FOPEN_CACHE_DIR (1 << 3) #define FOPEN_STREAM (1 << 4) +#define FOPEN_NOFLUSH (1 << 5) /** * INIT request/reply flags