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 762CCC433EF for ; Tue, 18 Jan 2022 16:12:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346670AbiARQMT (ORCPT ); Tue, 18 Jan 2022 11:12:19 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:41722 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346887AbiARQKl (ORCPT ); Tue, 18 Jan 2022 11:10:41 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 916DD61330; Tue, 18 Jan 2022 16:10:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57B0AC00446; Tue, 18 Jan 2022 16:10:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1642522240; bh=C5aujnFJ1NRiwxgdObOzedAoYWgfCW1MQquWKOgJ0yI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hxAwAvvFCTex9KM5f4pcZe2zJbS+7bI2q/lNNjXYEBSj59SMDFgnIAdVQ8mXlmN42 nnOO2dTV4N0p2N6cOzoQfmTL6LyWKurunwiEs/jKmZVI2zicFFTb6bQzPRUSaw/KNG VYsUykYtgCFRKjVOECm9Plm0LVkt/nTVVnvUuC/c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Howells , Dominique Martinet Subject: [PATCH 5.16 14/28] 9p: fix enodata when reading growing file Date: Tue, 18 Jan 2022 17:06:09 +0100 Message-Id: <20220118160452.878838210@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220118160452.384322748@linuxfoundation.org> References: <20220118160452.384322748@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dominique Martinet commit 19d1c32652bbbf406063025354845fdddbcecd3a upstream. Reading from a file that was just extended by a write, but the write had not yet reached the server would return ENODATA as illustrated by this command: $ xfs_io -c 'open -ft test' -c 'w 4096 1000' -c 'r 0 1000' wrote 1000/1000 bytes at offset 4096 1000.000000 bytes, 1 ops; 0.0001 sec (5.610 MiB/sec and 5882.3529 ops/sec) pread: No data available Fix this case by having netfs assume zeroes when reads from server come short like AFS and CEPH do Link: https://lkml.kernel.org/r/20220110111444.926753-1-asmadeus@codewreck.org Cc: stable@vger.kernel.org Fixes: eb497943fa21 ("9p: Convert to using the netfs helper lib to do reads and caching") Co-authored-by: David Howells Reviewed-by: David Howells Tested-by: David Howells Signed-off-by: Dominique Martinet Signed-off-by: Greg Kroah-Hartman --- fs/9p/vfs_addr.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -42,6 +42,11 @@ static void v9fs_req_issue_op(struct net iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len); total = p9_client_read(fid, pos, &to, &err); + + /* if we just extended the file size, any portion not in + * cache won't be on server and is zeroes */ + __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags); + netfs_subreq_terminated(subreq, err ?: total, false); }