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=-6.8 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS 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 225AAC0044C for ; Wed, 7 Nov 2018 06:40:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFBAE2081D for ; Wed, 7 Nov 2018 06:40:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CFBAE2081D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gmx.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-btrfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726604AbeKGQJW (ORCPT ); Wed, 7 Nov 2018 11:09:22 -0500 Received: from mout.gmx.net ([212.227.15.19]:38085 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726194AbeKGQJW (ORCPT ); Wed, 7 Nov 2018 11:09:22 -0500 Received: from [0.0.0.0] ([210.140.77.29]) by mail.gmx.com (mrgmx002 [212.227.17.184]) with ESMTPSA (Nemesis) id 0MGjL7-1gGD2o1u5Z-00DW1o; Wed, 07 Nov 2018 07:40:20 +0100 Received: from [0.0.0.0] ([210.140.77.29]) by mail.gmx.com (mrgmx002 [212.227.17.184]) with ESMTPSA (Nemesis) id 0MGjL7-1gGD2o1u5Z-00DW1o; Wed, 07 Nov 2018 07:40:20 +0100 Subject: Re: [PATCH 10/13] btrfs-progs: check: fix bug in find_possible_backrefs To: "Su Yanjun " , Su Yue , linux-btrfs@vger.kernel.org References: <20181023094147.7906-1-suy.fnst@cn.fujitsu.com> <20181023094147.7906-11-suy.fnst@cn.fujitsu.com> From: Qu Wenruo Openpgp: preference=signencrypt Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNIlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT7CwJQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWCnQUJCWYC bgAKCRDCPZHzoSX+qAR8B/94VAsSNygx1C6dhb1u1Wp1Jr/lfO7QIOK/nf1PF0VpYjTQ2au8 ihf/RApTna31sVjBx3jzlmpy+lDoPdXwbI3Czx1PwDbdhAAjdRbvBmwM6cUWyqD+zjVm4RTG rFTPi3E7828YJ71Vpda2qghOYdnC45xCcjmHh8FwReLzsV2A6FtXsvd87bq6Iw2axOHVUax2 FGSbardMsHrya1dC2jF2R6n0uxaIc1bWGweYsq0LXvLcvjWH+zDgzYCUB0cfb+6Ib/ipSCYp 3i8BevMsTs62MOBmKz7til6Zdz0kkqDdSNOq8LgWGLOwUTqBh71+lqN2XBpTDu1eLZaNbxSI ilaVzsBNBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAHCwHwEGAEIACYWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWBrwIbDAUJA8JnAAAK CRDCPZHzoSX+qA3xB/4zS8zYh3Cbm3FllKz7+RKBw/ETBibFSKedQkbJzRlZhBc+XRwF61mi f0SXSdqKMbM1a98fEg8H5kV6GTo62BzvynVrf/FyT+zWbIVEuuZttMk2gWLIvbmWNyrQnzPl mnjK4AEvZGIt1pk+3+N/CMEfAZH5Aqnp0PaoytRZ/1vtMXNgMxlfNnb96giC3KMR6U0E+siA 4V7biIoyNoaN33t8m5FwEwd2FQDG9dAXWhG13zcm9gnk63BN3wyCQR+X5+jsfBaS4dvNzvQv h8Uq/YGjCoV1ofKYh3WKMY8avjq25nlrhzD/Nto9jHp8niwr21K//pXVA81R2qaXqGbql+zo Message-ID: <51fa6a57-655e-347b-a75d-f5ca9c7640d9@gmx.com> Date: Wed, 7 Nov 2018 14:40:15 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:zPiVib7ROXfk3VRTeznvrGxBg6gRCL4hwNdrPyhXd7XYSPME6A4 1nBOQwfvWGPp+g4FjxVn0aFsghVvwMdd/u7+T9jM1cdMUxKZpNWSswtCRVG4ezzj8vSkR6r +IuLcmmGqQ9X2WtKhMbdGlT4XEI9vipaFGqEoV59/Ycbc0zVb3LYzn26qVlhAkN0o+392PN QsrqLLen3l3taauSWEndg== X-UI-Out-Filterresults: notjunk:1;V01:K0:1dTHTm0FDvg=:vqUYPlpIbyBim550974XzS M7ozCnPZWzFLfEt6mh65qEzQ501a/QSc3LAzBNA3wJPhSPguIHJfEWI+WCVgOlhAjR8eOsLQA /N3fz5flVSHoYV+yw0updhdGcI2961JB16ERWxANS9TiRTz4Gf93H4ZvSd4145yOFm2p0Y98P UlE5L/bWBpgmuiK1UrYyDiEPCZZibhjwQoQ+9p9nje4IYeLgjOgAywT8Ud/TI+UNN7BJebg7c 89uUWOAxiVJ0VIbY77cv+2wuSj9Oc0kqCD0YOe5efCQyjwjSbF0XDah1hbSJqBIJ8lAfzBy+Q 2ju2n6jnIOHF/FR7NywqAe1O8Gn+qspWP2WSHiBKYSYaOIc2uTav+1J1+9asA+RvAkxOhKOrT FY6zAP45WpM259oCjf9vzh8hjevQTvmdeJXq0oqLT11uf+G6GNWZAS+OKkivHBcStikBpO7ER RtrBykj4wt8FmXc23WCgK06gtl8dyxa5usFoi3Qr6047rnH9C9jTucPqFGlFtL9PrxS0CrDeU n/wutbMUYhJ8Rli+bg2Sh868bqk4NHCVuUfApo1lp0pCrZLREfXg3hzdOY+lreWpEYbCf1g7M nnUn6XGhk1M4SJ9PXKrqEMUFjlHHVAUE3tWVAbCIdmpBE1bUCBjTFNlA6+q8qUkcU452czBaB bmGsuDffV77NCQo+uLijxPHwJkIHS+9DZoXTNj8Ta/urCYTLmdZZ08fXXrf7LYNU4XDaPPb8o DqwP5UYxxyyA7R5w4Bisyx3p3sejPtFt5EYm2QVmV3qhzIhWK3xah3rtrWIYtiBYaLi+HzADD 6o5JCbx/74wixYq0pCxKbjc/YcYRL+tbX+dbLqmo0c1NW/Z85U= Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2018/11/7 下午2:28, Su Yanjun wrote: > > > On 10/24/2018 8:34 AM, Qu Wenruo wrote: >> >> On 2018/10/23 下午5:41, Su Yue wrote: >>> From: Su Yanjun >>> >>> It may cost more time to search all extent data of correspond files but >>> should not influence total speed too much cause that only corrupted >>> extent items are participated in. >> Sorry, I didn't really get the point of the modification from the commit >> message. >> >> Would you please explain the purpose of this patch first? >> >> Thanks, >> Qu > > In find_possible_backrefs() function: > >     key.objectid = dback->owner; >     key.type = BTRFS_EXTENT_DATA_KEY; >     key.offset = dback->offset;// >     ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); > > 'dback->offset' is not the offset in file range, we'll find wrong file > extent. Now this makes sense. The original commit message doesn't touch this part, and focused on the side effect, not the problem itself. Please update the commit message. Thanks, Qu > > Thanks, > > Su > >>> Signed-off-by: Su Yanjun >>> --- >>>   check/main.c | 110 ++++++++++++++++++++++++++++++++++++++++++--------- >>>   1 file changed, 92 insertions(+), 18 deletions(-) >>> >>> diff --git a/check/main.c b/check/main.c >>> index bd1f322e0f12..90d9fd570287 100644 >>> --- a/check/main.c >>> +++ b/check/main.c >>> @@ -7015,6 +7015,89 @@ out: >>>       return ret ? ret : nr_del; >>>   } >>>   +/* >>> + * Based extent backref item, we find all file extent items in the >>> fs tree. By >>> + * the info we can rebuild the extent backref item >>> + */ >>> +static int __find_possible_backrefs(struct btrfs_root *root, >>> +        u64 owner, u64 offset, u64 bytenr, u64 *refs_ret, >>> +        u64 *bytes_ret) >>> +{ >>> +    int ret = 0; >>> +    struct btrfs_path path; >>> +    struct btrfs_key key; >>> +    struct btrfs_key found_key; >>> +    struct btrfs_file_extent_item *fi; >>> +    struct extent_buffer *leaf; >>> +    u64 backref_offset, disk_bytenr; >>> +    int slot; >>> + >>> +    btrfs_init_path(&path); >>> + >>> +    key.objectid = owner; >>> +    key.type = BTRFS_INODE_ITEM_KEY; >>> +    key.offset = 0; >>> + >>> +    ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0); >>> +    if (ret > 0) >>> +        ret = -ENOENT; >>> +    if (ret) { >>> +        btrfs_release_path(&path); >>> +        return ret; >>> +    } >>> + >>> +    btrfs_release_path(&path); >>> + >>> +    key.objectid = owner; >>> +    key.type = BTRFS_EXTENT_DATA_KEY; >>> +    key.offset = 0; >>> + >>> +    ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0); >>> +    if (ret < 0) { >>> +        btrfs_release_path(&path); >>> +        return ret; >>> +    } >>> + >>> +    while (1) { >>> +        leaf = path.nodes[0]; >>> +        slot = path.slots[0]; >>> + >>> +        if (slot >= btrfs_header_nritems(leaf)) { >>> +            ret = btrfs_next_leaf(root, &path); >>> +            if (ret) { >>> +                if (ret > 0) >>> +                    ret = 0; >>> +                break; >>> +            } >>> + >>> +            leaf = path.nodes[0]; >>> +            slot = path.slots[0]; >>> +        } >>> + >>> +        btrfs_item_key_to_cpu(leaf, &found_key, slot); >>> +        if ((found_key.objectid != owner) || >>> +            (found_key.type != BTRFS_EXTENT_DATA_KEY)) >>> +            break; >>> + >>> +        fi = btrfs_item_ptr(leaf, slot, >>> +                struct btrfs_file_extent_item); >>> + >>> +        backref_offset = found_key.offset - >>> +            btrfs_file_extent_offset(leaf, fi); >>> +        disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); >>> +        *bytes_ret = btrfs_file_extent_disk_num_bytes(leaf, >>> +                                fi); >>> +        if ((disk_bytenr == bytenr) && >>> +            (backref_offset == offset)) { >>> +            (*refs_ret)++; >>> +        } >>> +        path.slots[0]++; >>> +    } >>> + >>> +    btrfs_release_path(&path); >>> +    return ret; >>> +} >>> + >>>   static int find_possible_backrefs(struct btrfs_fs_info *info, >>>                     struct btrfs_path *path, >>>                     struct cache_tree *extent_cache, >>> @@ -7024,9 +7107,9 @@ static int find_possible_backrefs(struct >>> btrfs_fs_info *info, >>>       struct extent_backref *back, *tmp; >>>       struct data_backref *dback; >>>       struct cache_extent *cache; >>> -    struct btrfs_file_extent_item *fi; >>>       struct btrfs_key key; >>>       u64 bytenr, bytes; >>> +    u64 refs; >>>       int ret; >>>         rbtree_postorder_for_each_entry_safe(back, tmp, >>> @@ -7054,24 +7137,15 @@ static int find_possible_backrefs(struct >>> btrfs_fs_info *info, >>>           if (IS_ERR(root)) >>>               return PTR_ERR(root); >>>   -        key.objectid = dback->owner; >>> -        key.type = BTRFS_EXTENT_DATA_KEY; >>> -        key.offset = dback->offset; >>> -        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); >>> -        if (ret) { >>> -            btrfs_release_path(path); >>> -            if (ret < 0) >>> -                return ret; >>> -            /* Didn't find it, we can carry on */ >>> -            ret = 0; >>> +        refs = 0; >>> +        bytes = 0; >>> +        ret = __find_possible_backrefs(root, dback->owner, >>> +                dback->offset, rec->start, &refs, &bytes); >>> +        if (ret) >>>               continue; >>> -        } >>>   -        fi = btrfs_item_ptr(path->nodes[0], path->slots[0], >>> -                    struct btrfs_file_extent_item); >>> -        bytenr = btrfs_file_extent_disk_bytenr(path->nodes[0], fi); >>> -        bytes = btrfs_file_extent_disk_num_bytes(path->nodes[0], fi); >>> -        btrfs_release_path(path); >>> +        bytenr = rec->start; >>> + >>>           cache = lookup_cache_extent(extent_cache, bytenr, 1); >>>           if (cache) { >>>               struct extent_record *tmp; >>> @@ -7090,7 +7164,7 @@ static int find_possible_backrefs(struct >>> btrfs_fs_info *info, >>>                   continue; >>>           } >>>   -        dback->found_ref += 1; >>> +        dback->found_ref += refs; >>>           dback->disk_bytenr = bytenr; >>>           dback->bytes = bytes; >>>   >> > > >