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[2620:137:e000::1:20]) by mx.google.com with ESMTP id k186-20020a6384c3000000b0054405493a4dsi7555125pgd.199.2023.06.27.10.38.43; Tue, 27 Jun 2023 10:38:55 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@nabijaczleweli.xyz header.s=202305 header.b=OnmsF1+l; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nabijaczleweli.xyz Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229804AbjF0Qzx (ORCPT + 99 others); Tue, 27 Jun 2023 12:55:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229690AbjF0Qzu (ORCPT ); Tue, 27 Jun 2023 12:55:50 -0400 Received: from tarta.nabijaczleweli.xyz (unknown [139.28.40.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id A705310DA; Tue, 27 Jun 2023 09:55:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=nabijaczleweli.xyz; s=202305; t=1687884946; bh=Ry0ApNAVb50SUY2QJyeYNcjESfCK9nJXD87gDEkJ+YQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OnmsF1+lOLEYVPB0NGmpzo/9sxh+1my+cdRFWzkAgwdL2Gjc9fQeYY0ktoQQHvOF6 NJHHNKgE8W8LNqitno6cUX0tn5ZTFXrXUgOJzeL9Ce4A8L+O3+yLBBWM5P/lREF/ES rVJoOiR2BPG0egC/DV3Hm81JPAYXyyDJGQFruoreds1yB+49Faj1NvUNUXPMcSo+Yw 7Sixjr35wmqyjMo2VIVcyjB+00hG2KoPT8/IdCvly9m4SFoZjAS5xk/Yb7EQj52fBL o2MvmhtZep+VL7fforI3aTqC3BnD4m8oLcqIXlDC/QSpeJ6sFAseZeQnATxRnfcU2q CDn8aXOjjo8ug== Received: from tarta.nabijaczleweli.xyz (unknown [192.168.1.250]) by tarta.nabijaczleweli.xyz (Postfix) with ESMTPSA id 011EC1A8C; Tue, 27 Jun 2023 18:55:46 +0200 (CEST) Date: Tue, 27 Jun 2023 18:55:44 +0200 From: Ahelenia =?utf-8?q?Ziemia=C5=84ska?= To: Amir Goldstein Cc: Alexander Viro , Christian Brauner , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Jan Kara , Chung-Chiang Cheng , ltp@vger.kernel.org Subject: [PATCH v3 1/3] splice: always fsnotify_access(in), fsnotify_modify(out) on success Message-ID: <8827a512f0974b9f261887d344c3b1ffde7b21e5.1687884031.git.nabijaczleweli@nabijaczleweli.xyz> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20230517 X-Spam-Status: No, score=-1.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,PDS_RDNS_DYNAMIC_FP, RDNS_DYNAMIC,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1769878360734915531?= X-GMAIL-MSGID: =?utf-8?q?1769878360734915531?= The current behaviour caused an asymmetry where some write APIs (write, sendfile) would notify the written-to/read-from objects, but splice wouldn't. This affected userspace which uses inotify, most notably coreutils tail -f, to monitor pipes. If the pipe buffer had been filled by a splice-family function: * tail wouldn't know and thus wouldn't service the pipe, and * all writes to the pipe would block because it's full, thus service was denied. (For the particular case of tail -f this could be worked around with ---disable-inotify.) Fixes: 983652c69199 ("splice: report related fsnotify events") Link: https://lore.kernel.org/linux-fsdevel/jbyihkyk5dtaohdwjyivambb2gffyjs3dodpofafnkkunxq7bu@jngkdxx65pux/t/#u Link: https://bugs.debian.org/1039488 Signed-off-by: Ahelenia Ziemiańska Reviewed-by: Amir Goldstein --- fs/splice.c | 31 ++++++++++++++----------------- 1 file changed, 14 insertions(+), 17 deletions(-) diff --git a/fs/splice.c b/fs/splice.c index 3e06611d19ae..e16f4f032d2f 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1154,10 +1154,8 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out, if ((in->f_flags | out->f_flags) & O_NONBLOCK) flags |= SPLICE_F_NONBLOCK; - return splice_pipe_to_pipe(ipipe, opipe, len, flags); - } - - if (ipipe) { + ret = splice_pipe_to_pipe(ipipe, opipe, len, flags); + } else if (ipipe) { if (off_in) return -ESPIPE; if (off_out) { @@ -1182,18 +1180,15 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out, ret = do_splice_from(ipipe, out, &offset, len, flags); file_end_write(out); - if (ret > 0) - fsnotify_modify(out); - if (!off_out) out->f_pos = offset; else *off_out = offset; - return ret; - } - - if (opipe) { + // splice_write-> already marked out + // as modified via vfs_iter_write() + goto noaccessout; + } else if (opipe) { if (off_out) return -ESPIPE; if (off_in) { @@ -1209,18 +1204,20 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out, ret = splice_file_to_pipe(in, opipe, &offset, len, flags); - if (ret > 0) - fsnotify_access(in); - if (!off_in) in->f_pos = offset; else *off_in = offset; + } else + return -EINVAL; - return ret; - } + if (ret > 0) + fsnotify_modify(out); +noaccessout: + if (ret > 0) + fsnotify_access(in); - return -EINVAL; + return ret; } static long __do_splice(struct file *in, loff_t __user *off_in,