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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 3A20FC4332F for ; Fri, 4 Nov 2022 05:40:48 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4N3TxV5TR1z3ccq for ; Fri, 4 Nov 2022 16:40:46 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.alibaba.com (client-ip=115.124.30.44; helo=out30-44.freemail.mail.aliyun.com; envelope-from=jefflexu@linux.alibaba.com; receiver=) Received: from out30-44.freemail.mail.aliyun.com (out30-44.freemail.mail.aliyun.com [115.124.30.44]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4N3TxJ24b4z3cJY for ; Fri, 4 Nov 2022 16:40:35 +1100 (AEDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R381e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046060;MF=jefflexu@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VTvadhw_1667540430; Received: from localhost(mailfrom:jefflexu@linux.alibaba.com fp:SMTPD_---0VTvadhw_1667540430) by smtp.aliyun-inc.com; Fri, 04 Nov 2022 13:40:31 +0800 From: Jingbo Xu To: xiang@kernel.org, chao@kernel.org, huyue2@coolpad.com, linux-erofs@lists.ozlabs.org Subject: [PATCH 2/2] erofs: get correct count for unmapped range in fscache mode Date: Fri, 4 Nov 2022 13:40:28 +0800 Message-Id: <20221104054028.52208-3-jefflexu@linux.alibaba.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20221104054028.52208-1-jefflexu@linux.alibaba.com> References: <20221104054028.52208-1-jefflexu@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, yinxin.x@bytedance.com Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" For unmapped range, the returned map.m_llen is zero, and thus the calculated count is unexpected zero. Prior to the refactoring introduced by commit 1ae9470c3e14 ("erofs: clean up .read_folio() and .readahead() in fscache mode"), only the readahead routine suffers from this. With the refactoring of making .read_folio() and .readahead() calling one common routine, both read_folio and readahead have this issue now. Fix this by calculating count separately in unmapped condition. Fixes: c665b394b9e8 ("erofs: implement fscache-based data readahead") Fixes: 1ae9470c3e14 ("erofs: clean up .read_folio() and .readahead() in fscache mode") Signed-off-by: Jingbo Xu --- fs/erofs/fscache.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index 83559008bfa8..260fa4737fc0 100644 --- a/fs/erofs/fscache.c +++ b/fs/erofs/fscache.c @@ -296,15 +296,16 @@ static int erofs_fscache_data_read(struct address_space *mapping, return PAGE_SIZE; } - count = min_t(size_t, map.m_llen - (pos - map.m_la), len); - DBG_BUGON(!count || count % PAGE_SIZE); - if (!(map.m_flags & EROFS_MAP_MAPPED)) { + count = len; iov_iter_xarray(&iter, READ, &mapping->i_pages, pos, count); iov_iter_zero(count, &iter); return count; } + count = min_t(size_t, map.m_llen - (pos - map.m_la), len); + DBG_BUGON(!count || count % PAGE_SIZE); + mdev = (struct erofs_map_dev) { .m_deviceid = map.m_deviceid, .m_pa = map.m_pa, -- 2.19.1.6.gb485710b