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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 72A13ECDFB0 for ; Fri, 13 Jul 2018 03:42:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E6799214AB for ; Fri, 13 Jul 2018 03:42:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E6799214AB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387946AbeGMDzN (ORCPT ); Thu, 12 Jul 2018 23:55:13 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:35562 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387722AbeGMDzN (ORCPT ); Thu, 12 Jul 2018 23:55:13 -0400 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 700A7A72A19A3; Fri, 13 Jul 2018 11:42:31 +0800 (CST) Received: from [127.0.0.1] (10.134.22.195) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.382.0; Fri, 13 Jul 2018 11:42:25 +0800 Subject: Re: [PATCH 2/5] f2fs: clear the remaining prefree_map of the section To: Yunlong Song , , , CC: , , , , , References: <1531408170-45758-1-git-send-email-yunlong.song@huawei.com> <1531408170-45758-3-git-send-email-yunlong.song@huawei.com> <75dc9cad-8166-82c5-e085-88c9623f5c5e@huawei.com> From: Chao Yu Message-ID: <12f3c3d2-6586-ca73-8770-8f97b436d643@huawei.com> Date: Fri, 13 Jul 2018 11:42:25 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <75dc9cad-8166-82c5-e085-88c9623f5c5e@huawei.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/7/13 11:28, Yunlong Song wrote: > round 1: section bitmap : 1 1 1 1 1, all valid, prefree_map: 0 0 0 0 0 > then rm data block NO.2, block NO.2 becomes invalid, prefree_map: 0 0 1 0 0 > write_checkpoint: section bitmap: 1 1 0 1 1, prefree_map: 0 0 0 0 0, > prefree of NO.2 is cleared, and no discard issued > > round2: rm data block NO.0, NO.1, NO.3, NO.4 > all invalid, but prefree bit of NO.2 is set and cleared in round1, then > prefree_map: 1 1 0 1 1 > write_checkpoint: section bitmap: 0 0 0 0 0, prefree_map: 0 0 0 1 1, no Why prefree_map is not 0 0 0 0 0? Thanks, > valid blocks of this section, so discard issued > but this time prefree bit of NO.3 and NO.4 is skipped... > > round3: > write_checkpoint: section bitmap: 0 0 0 0 0, prefree_map: 0 0 0 1 1 - > > 0 0 0 0 0, no valid blocks of this section, so discard issued > this time prefree bit of NO.3 and NO.4 is cleared, but the discard of > this section is sent again... > > On 2018/7/13 11:13, Chao Yu wrote: >> On 2018/7/12 23:09, Yunlong Song wrote: >>> For the case when sbi->segs_per_sec > 1, take section:segment = 5 for >>> example, if the section prefree_map is ...previous section | current >>> section (1 1 0 1 1) | next section..., then the start = x, end = x + 1, >>> after start = start_segno + sbi->segs_per_sec, start = x + 5, then it >>> will skip x + 3 and x + 4, but their bitmap is still set, which will >>> cause duplicated f2fs_issue_discard of this same section in the next >>> write_checkpoint, so fix it. >> I didn't get it, if # 2 segment is not prefree state, so it still has valid >> blocks there, so we won't issue discard due to below condition, right? >> >> if (!IS_CURSEC(sbi, secno) && >> !get_valid_blocks(sbi, start, true)) >> >> Thanks, >> >>> Signed-off-by: Yunlong Song >>> --- >>> fs/f2fs/segment.c | 19 +++++++++++++++++-- >>> 1 file changed, 17 insertions(+), 2 deletions(-) >>> >>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >>> index 47b6595..fd38b61 100644 >>> --- a/fs/f2fs/segment.c >>> +++ b/fs/f2fs/segment.c >>> @@ -1684,8 +1684,23 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi, >>> start = start_segno + sbi->segs_per_sec; >>> if (start < end) >>> goto next; >>> - else >>> - end = start - 1; >>> + else { >>> + start_segno = start; >>> + >>> + while (1) { >>> + start = find_next_bit(prefree_map, start_segno, >>> + end + 1); >>> + if (start >= start_segno) >>> + break; >>> + end = find_next_zero_bit(prefree_map, start_segno, >>> + start + 1); >>> + for (i = start; i < end; i++) >>> + clear_bit(i, prefree_map); >>> + dirty_i->nr_dirty[PRE] -= end - start; >>> + } >>> + >>> + end = start_segno - 1; >>> + } >>> } >>> mutex_unlock(&dirty_i->seglist_lock); >>> >>> >> >> . >> >