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=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 5D5A5C433DF for ; Wed, 19 Aug 2020 01:36:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3E8E6208DB for ; Wed, 19 Aug 2020 01:36:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727830AbgHSBf6 (ORCPT ); Tue, 18 Aug 2020 21:35:58 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:41844 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726367AbgHSBf6 (ORCPT ); Tue, 18 Aug 2020 21:35:58 -0400 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id D0006D65640004EEF6EB; Wed, 19 Aug 2020 09:35:54 +0800 (CST) Received: from [10.136.114.67] (10.136.114.67) by smtp.huawei.com (10.3.19.214) with Microsoft SMTP Server (TLS) id 14.3.487.0; Wed, 19 Aug 2020 09:35:53 +0800 Subject: Re: [PATCH v2] f2fs: fix indefinite loop scanning for free nid To: Sahitya Tummala , Jaegeuk Kim , CC: References: <1597745414-13135-1-git-send-email-stummala@codeaurora.org> From: Chao Yu Message-ID: Date: Wed, 19 Aug 2020 09:35:52 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1597745414-13135-1-git-send-email-stummala@codeaurora.org> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.136.114.67] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/8/18 18:10, Sahitya Tummala wrote: > If the sbi->ckpt->next_free_nid is not NAT block aligned and if there > are free nids in that NAT block between the start of the block and > next_free_nid, then those free nids will not be scanned in scan_nat_page(). > This results into mismatch between nm_i->available_nids and the sum of > nm_i->free_nid_count of all NAT blocks scanned. And nm_i->available_nids > will always be greater than the sum of free nids in all the blocks. > Under this condition, if we use all the currently scanned free nids, > then it will loop forever in f2fs_alloc_nid() as nm_i->available_nids > is still not zero but nm_i->free_nid_count of that partially scanned > NAT block is zero. > > Fix this to align the nm_i->next_scan_nid to the first nid of the > corresponding NAT block. > > Signed-off-by: Sahitya Tummala Reviewed-by: Chao Yu > During CP we update only ckpt->next_free_nid but not > the nm_i->next_free_nid, which is done only once during boot up. Oops, thanks for correcting that... Thanks,