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 X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33F20C43381 for ; Fri, 22 Mar 2019 12:11:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 06C342192C for ; Fri, 22 Mar 2019 12:11:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553256660; bh=oA0WJM1I0IQaPmAjsJZgMNExtqMo/FS2woJGpcr3H9E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jbBl9pa8yIk+gCeSJjZIgctt5xD8tWjcDEoZsizl5TxSJVGwasa6AU7O4GpXK9EvF w5x8xzpr1nn5MuVCtYVvlOtzy1xGC2GSxqGhhvD40nj+Smgox5Ltgmo71JkjE5Tj2Q eL/PRvuBB8w2U63o2Uik4uA7+Cda/KtoNUs6c8Cw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388912AbfCVMK6 (ORCPT ); Fri, 22 Mar 2019 08:10:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:49318 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389473AbfCVMK6 (ORCPT ); Fri, 22 Mar 2019 08:10:58 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 53A192082C; Fri, 22 Mar 2019 12:10:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553256656; bh=oA0WJM1I0IQaPmAjsJZgMNExtqMo/FS2woJGpcr3H9E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lmWcr7uUVZYhFN6JqgQZupxc0MjGqws/JMXee1F1n0CDLHrrMjIL/2IFDJByoNtoR lXpQkSMc8tHZki9d4bQj64u7PZFfZP/MEIeli2AA1nzJXu2JWC20nJp/KCNbsjKKjl 0CRijDdx1CL+4TsqM5YVdI063XJ2jkFGkSHEfrGc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nix , Coly Li , Andre Noll , Dave Chinner , Christoph Hellwig , Jens Axboe Subject: [PATCH 4.19 279/280] bcache: use (REQ_META|REQ_PRIO) to indicate bio for metadata Date: Fri, 22 Mar 2019 12:17:12 +0100 Message-Id: <20190322111347.937046833@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190322111306.356185024@linuxfoundation.org> References: <20190322111306.356185024@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Coly Li commit dc7292a5bcb4c878b076fca2ac3fc22f81b8f8df upstream. In 'commit 752f66a75aba ("bcache: use REQ_PRIO to indicate bio for metadata")' REQ_META is replaced by REQ_PRIO to indicate metadata bio. This assumption is not always correct, e.g. XFS uses REQ_META to mark metadata bio other than REQ_PRIO. This is why Nix noticed that bcache does not cache metadata for XFS after the above commit. Thanks to Dave Chinner, he explains the difference between REQ_META and REQ_PRIO from view of file system developer. Here I quote part of his explanation from mailing list, REQ_META is used for metadata. REQ_PRIO is used to communicate to the lower layers that the submitter considers this IO to be more important that non REQ_PRIO IO and so dispatch should be expedited. IOWs, if the filesystem considers metadata IO to be more important that user data IO, then it will use REQ_PRIO | REQ_META rather than just REQ_META. Then it seems bios with REQ_META or REQ_PRIO should both be cached for performance optimation, because they are all probably low I/O latency demand by upper layer (e.g. file system). So in this patch, when we want to decide whether to bypass the cache, REQ_META and REQ_PRIO are both checked. Then both metadata and high priority I/O requests will be handled properly. Reported-by: Nix Signed-off-by: Coly Li Reviewed-by: Andre Noll Tested-by: Nix Cc: stable@vger.kernel.org Cc: Dave Chinner Cc: Christoph Hellwig Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/md/bcache/request.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -392,10 +392,11 @@ static bool check_should_bypass(struct c /* * Flag for bypass if the IO is for read-ahead or background, - * unless the read-ahead request is for metadata (eg, for gfs2). + * unless the read-ahead request is for metadata + * (eg, for gfs2 or xfs). */ if (bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND) && - !(bio->bi_opf & REQ_META)) + !(bio->bi_opf & (REQ_META|REQ_PRIO))) goto skip; if (bio->bi_iter.bi_sector & (c->sb.block_size - 1) || @@ -877,7 +878,7 @@ static int cached_dev_cache_miss(struct } if (!(bio->bi_opf & REQ_RAHEAD) && - !(bio->bi_opf & REQ_META) && + !(bio->bi_opf & (REQ_META|REQ_PRIO)) && s->iop.c->gc_stats.in_use < CUTOFF_CACHE_READA) reada = min_t(sector_t, dc->readahead >> 9, get_capacity(bio->bi_disk) - bio_end_sector(bio));