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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 A8BB3EE14A9 for ; Wed, 6 Sep 2023 22:45:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694040331; h=from:from:sender:sender: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:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=ku52I7/1S6jFBZ/uuQO3CDZbakSDTxVE75LPO0KTjsc=; b=NvBNAox4HoJtwJjlOKOK+ZPjmZKYT2wTHN303jnoQO4oqIZZ4FUjK/QMk8vhIzKD6Ll8sC f1LK2uf+IAoNfspS92EREJeBffzICcDjPun72SlF2CgZtkK7F3aRlRFTxm5so13yYlcnsy tIoysDIddjulfamgHlznm5m28RLGj8c= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-30-xCpeNBTnOw2wSfrS2gCJLQ-1; Wed, 06 Sep 2023 18:45:28 -0400 X-MC-Unique: xCpeNBTnOw2wSfrS2gCJLQ-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 674778164E1; Wed, 6 Sep 2023 22:45:26 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id 54554404119; Wed, 6 Sep 2023 22:45:26 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 22F61194658D; Wed, 6 Sep 2023 22:45:26 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 5B3E61946594 for ; Wed, 6 Sep 2023 22:45:24 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 2E255412F2CF; Wed, 6 Sep 2023 22:45:24 +0000 (UTC) Received: from octiron.msp.redhat.com (octiron.msp.redhat.com [10.15.80.209]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1657C412F2CE; Wed, 6 Sep 2023 22:45:24 +0000 (UTC) Received: from octiron.msp.redhat.com (localhost.localdomain [127.0.0.1]) by octiron.msp.redhat.com (8.14.9/8.14.9) with ESMTP id 386MjFxl028985; Wed, 6 Sep 2023 17:45:16 -0500 Received: (from bmarzins@localhost) by octiron.msp.redhat.com (8.14.9/8.14.9/Submit) id 386MjFno028984; Wed, 6 Sep 2023 17:45:15 -0500 Date: Wed, 6 Sep 2023 17:45:15 -0500 From: Benjamin Marzinski To: mwilck@suse.com Message-ID: <20230906224515.GZ7412@octiron.msp.redhat.com> References: <20230901180235.23980-1-mwilck@suse.com> <20230901180235.23980-16-mwilck@suse.com> MIME-Version: 1.0 In-Reply-To: <20230901180235.23980-16-mwilck@suse.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Subject: Re: [dm-devel] [PATCH 15/21] libmultipath: update_bindings_file: use a single write() X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dm-devel@redhat.com Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Fri, Sep 01, 2023 at 08:02:28PM +0200, mwilck@suse.com wrote: > From: Martin Wilck > > Save code and syscalls by assembling the content in memory first. > write() may return less bytes written than expected. Deal with it. > Reviewed-by: Benjamin Marzinski > Signed-off-by: Martin Wilck > --- > libmultipath/alias.c | 26 +++++++++++++++++--------- > 1 file changed, 17 insertions(+), 9 deletions(-) > > diff --git a/libmultipath/alias.c b/libmultipath/alias.c > index 76d852f..c26f37c 100644 > --- a/libmultipath/alias.c > +++ b/libmultipath/alias.c > @@ -118,22 +118,30 @@ static int add_binding(Bindings *bindings, const char *alias, const char *wwid) > static int write_bindings_file(const Bindings *bindings, int fd) > { > struct binding *bnd; > - STRBUF_ON_STACK(line); > + STRBUF_ON_STACK(content); > int i; > + size_t len; > > - if (write(fd, BINDINGS_FILE_HEADER, sizeof(BINDINGS_FILE_HEADER) - 1) > - != sizeof(BINDINGS_FILE_HEADER) - 1) > + if (__append_strbuf_str(&content, BINDINGS_FILE_HEADER, > + sizeof(BINDINGS_FILE_HEADER) - 1) == -1) > return -1; > > vector_foreach_slot(bindings, bnd, i) { > - int len; > + if (print_strbuf(&content, "%s %s\n", > + bnd->alias, bnd->wwid) < 0) > + return -1; > + } > + len = get_strbuf_len(&content); > + while (len > 0) { > + ssize_t n = write(fd, get_strbuf_str(&content), len); > > - if ((len = print_strbuf(&line, "%s %s\n", > - bnd->alias, bnd->wwid)) < 0) > + if (n < 0) > + return n; > + else if (n == 0) { > + condlog(2, "%s: short write", __func__); > return -1; > - if (write(fd, get_strbuf_str(&line), len) != len) > - return -1; > - truncate_strbuf(&line, 0); > + } > + len -= n; > } > return 0; > } > -- > 2.41.0 -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel