From patchwork Mon May 25 22:08:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Simmons X-Patchwork-Id: 11569585 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5BE0C60D for ; Mon, 25 May 2020 22:10:27 +0000 (UTC) Received: from pdx1-mailman02.dreamhost.com (pdx1-mailman02.dreamhost.com [64.90.62.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 44D312071A for ; Mon, 25 May 2020 22:10:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 44D312071A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lustre-devel-bounces@lists.lustre.org Received: from pdx1-mailman02.dreamhost.com (localhost [IPv6:::1]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id 1AFBE24752E; Mon, 25 May 2020 15:09:42 -0700 (PDT) X-Original-To: lustre-devel@lists.lustre.org Delivered-To: lustre-devel-lustre.org@pdx1-mailman02.dreamhost.com Received: from smtp4.ccs.ornl.gov (smtp4.ccs.ornl.gov [160.91.203.40]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id F158321F76C for ; Mon, 25 May 2020 15:08:39 -0700 (PDT) Received: from star.ccs.ornl.gov (star.ccs.ornl.gov [160.91.202.134]) by smtp4.ccs.ornl.gov (Postfix) with ESMTP id 532481005EEA; Mon, 25 May 2020 18:08:27 -0400 (EDT) Received: by star.ccs.ornl.gov (Postfix, from userid 2004) id 5254A49D; Mon, 25 May 2020 18:08:27 -0400 (EDT) From: James Simmons To: Andreas Dilger , Oleg Drokin , NeilBrown Date: Mon, 25 May 2020 18:08:08 -0400 Message-Id: <1590444502-20533-32-git-send-email-jsimmons@infradead.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1590444502-20533-1-git-send-email-jsimmons@infradead.org> References: <1590444502-20533-1-git-send-email-jsimmons@infradead.org> Subject: [lustre-devel] [PATCH 31/45] lustre: llite: fix possible divide zero in ll_use_fast_io() X-BeenThere: lustre-devel@lists.lustre.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "For discussing Lustre software development." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wang Shilong , Lustre Development List MIME-Version: 1.0 Errors-To: lustre-devel-bounces@lists.lustre.org Sender: "lustre-devel" From: Wang Shilong ll_use_fast_io() is used to check wheather we could use fast IO. Since it is called in fast path, we don't hold ras_lock to protect access, there might have the race @ras_stride_bytes is reset after stride_io_mode() check. Fixes: 52fa1b524a84 ("lustre: llite: try fast io for stride io correctly") WC-bug-id: https://jira.whamcloud.com/browse/LU-13541 Lustre-commit: 7cd0afe58321 ("LU-13541 llite: fix possible divide zero in ll_use_fast_io()") Signed-off-by: Wang Shilong Reviewed-on: https://review.whamcloud.com/38545 Reviewed-by: Andreas Dilger Tested-by: Andreas Dilger Reviewed-by: Jian Yu Reviewed-by: James Nunez Signed-off-by: James Simmons --- fs/lustre/llite/rw.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/lustre/llite/rw.c b/fs/lustre/llite/rw.c index 9e004f4..fd0bed6 100644 --- a/fs/lustre/llite/rw.c +++ b/fs/lustre/llite/rw.c @@ -1609,10 +1609,11 @@ static bool ll_use_fast_io(struct file *file, unsigned long fast_read_pages = max(RA_REMAIN_WINDOW_MIN, ras->ras_rpc_pages); loff_t skip_pages; + loff_t stride_bytes = ras->ras_stride_bytes; - if (stride_io_mode(ras)) { + if (stride_io_mode(ras) && stride_bytes) { skip_pages = (ras->ras_stride_length + - ras->ras_stride_bytes - 1) / ras->ras_stride_bytes; + ras->ras_stride_bytes - 1) / stride_bytes; skip_pages *= fast_read_pages; } else { skip_pages = fast_read_pages;