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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67EE8C433EF for ; Mon, 25 Apr 2022 14:10:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232677AbiDYONc (ORCPT ); Mon, 25 Apr 2022 10:13:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229570AbiDYONa (ORCPT ); Mon, 25 Apr 2022 10:13:30 -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 ESMTP id A88891FCC7 for ; Mon, 25 Apr 2022 07:10:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1650895824; 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: in-reply-to:in-reply-to:references:references; bh=bQqZOAGGz8cVHdnTZIYoAUITNiAmyVcVqVE5emNQD/c=; b=HM2a++OoXmTsZmQnJWNobYPQoWlwkPhAPWdkp3OELMqORys+N75Ln9tdiei6tlRRzxCpB+ +gRbdEDfG3qvxpu2UWlh/sPJc5a+gLzXF4XWVVDxElpfqQFq6qpuosa7eYM9XA0segaw3f fxFXA3lHwgR6zPUS6e6jRb1vG2OWUlw= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-546-BWga3YOdOem8z4yuh6x95g-1; Mon, 25 Apr 2022 10:10:19 -0400 X-MC-Unique: BWga3YOdOem8z4yuh6x95g-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D853E38337F6; Mon, 25 Apr 2022 14:10:18 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.13]) by smtp.corp.redhat.com (Postfix) with ESMTP id 075F5401E97; Mon, 25 Apr 2022 14:10:16 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <1050016.1650537372@warthog.procyon.org.uk> <1817268.LulUJvKFVv@silver> To: asmadeus@codewreck.org Cc: dhowells@redhat.com, Christian Schoenebeck , David Kahurani , davem@davemloft.net, ericvh@gmail.com, kuba@kernel.org, linux-kernel@vger.kernel.org, lucho@ionkov.net, netdev@vger.kernel.org, v9fs-developer@lists.sourceforge.net, Greg Kurz Subject: Re: 9p EBADF with cache enabled (Was: 9p fs-cache tests/benchmark (was: 9p fscache Duplicate cookie detected)) MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <3174157.1650895816.1@warthog.procyon.org.uk> Content-Transfer-Encoding: quoted-printable Date: Mon, 25 Apr 2022 15:10:16 +0100 Message-ID: <3174158.1650895816@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There may be a quick and dirty workaround. I think the problem is that un= less the O_APPEND read starts at the beginning of a page, netfs is going to enf= orce a read. Does the attached patch fix the problem? (note that it's unteste= d) Also, can you get the contents of /proc/fs/fscache/stats from after reproducing the problem? David --- diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c index 501128188343..5f61fdb950b0 100644 --- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -291,16 +291,25 @@ static int v9fs_write_end(struct file *filp, struct = address_space *mapping, struct folio *folio =3D page_folio(subpage); struct inode *inode =3D mapping->host; struct v9fs_inode *v9inode =3D V9FS_I(inode); + size_t fsize =3D folio_size(folio); + size_t offset =3D pos & (fsize - 1); + /* With multipage folio support, we may be given len > fsize */ + size_t copy_size =3D min_t(size_t, len, fsize - offset); = p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); = if (!folio_test_uptodate(folio)) { - if (unlikely(copied < len)) { + if (unlikely(copied < copy_size)) { copied =3D 0; goto out; } - - folio_mark_uptodate(folio); + if (offset =3D=3D 0) { + if (copied =3D=3D fsize) + folio_mark_uptodate(folio); + /* Could clear to end of page if last_pos =3D=3D new EOF + * and then mark uptodate + */ + } } = /* diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 281a88a5b8dc..78439f628c23 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -364,6 +364,12 @@ int netfs_write_begin(struct file *file, struct addre= ss_space *mapping, if (folio_test_uptodate(folio)) goto have_folio; = + if (!netfs_is_cache_enabled(ctx) && + (file->f_flags & (O_APPEND | O_ACCMODE)) =3D=3D (O_APPEND | O_WRONLY= )) { + netfs_stat(&netfs_n_rh_write_append); + goto have_folio_no_wait; + } + /* If the page is beyond the EOF, we want to clear it - unless it's * within the cache granule containing the EOF, in which case we need * to preload the granule. diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index b7b0e3d18d9e..a1cd649197dc 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -67,6 +67,7 @@ extern atomic_t netfs_n_rh_read_failed; extern atomic_t netfs_n_rh_zero; extern atomic_t netfs_n_rh_short_read; extern atomic_t netfs_n_rh_write; +extern atomic_t netfs_n_rh_write_append; extern atomic_t netfs_n_rh_write_begin; extern atomic_t netfs_n_rh_write_done; extern atomic_t netfs_n_rh_write_failed; diff --git a/fs/netfs/stats.c b/fs/netfs/stats.c index 5510a7a14a40..fce87f86f950 100644 --- a/fs/netfs/stats.c +++ b/fs/netfs/stats.c @@ -23,6 +23,7 @@ atomic_t netfs_n_rh_read_failed; atomic_t netfs_n_rh_zero; atomic_t netfs_n_rh_short_read; atomic_t netfs_n_rh_write; +atomic_t netfs_n_rh_write_append; atomic_t netfs_n_rh_write_begin; atomic_t netfs_n_rh_write_done; atomic_t netfs_n_rh_write_failed; @@ -37,10 +38,11 @@ void netfs_stats_show(struct seq_file *m) atomic_read(&netfs_n_rh_write_zskip), atomic_read(&netfs_n_rh_rreq), atomic_read(&netfs_n_rh_sreq)); - seq_printf(m, "RdHelp : ZR=3D%u sh=3D%u sk=3D%u\n", + seq_printf(m, "RdHelp : ZR=3D%u sh=3D%u sk=3D%u wa=3D%u\n", atomic_read(&netfs_n_rh_zero), atomic_read(&netfs_n_rh_short_read), - atomic_read(&netfs_n_rh_write_zskip)); + atomic_read(&netfs_n_rh_write_zskip), + atomic_read(&netfs_n_rh_write_append)); seq_printf(m, "RdHelp : DL=3D%u ds=3D%u df=3D%u di=3D%u\n", atomic_read(&netfs_n_rh_download), atomic_read(&netfs_n_rh_download_done),