From patchwork Mon Aug 19 00:53:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zizhi Wo X-Patchwork-Id: 13767692 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 94E341BDC8; Mon, 19 Aug 2024 00:57:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.187 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724029076; cv=none; b=naFJfG7gZnTUsEWzxjsXWJ6KG1ElZ0twgB2ejwJDelPN/wuERVvNjJtTStFJahCyc4dxGgfTY1dMF9xZl//+B3kfIu61PCVkxkRgh8Peq6OC0+kQPjG9IzZhxa8XsorgXCH4mWL8ghsNMOw88UyUnjsOHiKY2CVNoBkjpalQ3uY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724029076; c=relaxed/simple; bh=VswoMa6/q8uxfd6GJxPzq1IB2NeWhuBVoTOwLQkkWhY=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=rl6ZO7POv4N4hJa26ZyuVf9KnNc8zJbr0UK0RjTM0TkAZD8o8SwxqNdwZ6C8BZpwFJfk7oNFSefFQp9o64Q74Vhe2TurkLSoxxVdYnBDnef/d2Qt3ZlbmBWRQKMBaZVgVbEttZ5mqdxOF/IQESGz0MC+7Kt7nhMzHdmxZW6awa8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.48]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4WnDhW0PDyzyQ93; Mon, 19 Aug 2024 08:57:15 +0800 (CST) Received: from kwepemf100017.china.huawei.com (unknown [7.202.181.16]) by mail.maildlp.com (Postfix) with ESMTPS id 1E975180064; Mon, 19 Aug 2024 08:57:51 +0800 (CST) Received: from localhost.localdomain (10.175.104.67) by kwepemf100017.china.huawei.com (7.202.181.16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 19 Aug 2024 08:57:50 +0800 From: Zizhi Wo To: , , , , CC: , , , Subject: [PATCH V4 2/2] xfs: Fix missing interval for missing_owner in xfs fsmap Date: Mon, 19 Aug 2024 08:53:20 +0800 Message-ID: <20240819005320.304211-3-wozizhi@huawei.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240819005320.304211-1-wozizhi@huawei.com> References: <20240819005320.304211-1-wozizhi@huawei.com> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemf100017.china.huawei.com (7.202.181.16) In the fsmap query of xfs, there is an interval missing problem: [root@fedora ~]# xfs_io -c 'fsmap -vvvv' /mnt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 253:16 [0..7]: static fs metadata 0 (0..7) 8 1: 253:16 [8..23]: per-AG metadata 0 (8..23) 16 2: 253:16 [24..39]: inode btree 0 (24..39) 16 3: 253:16 [40..47]: per-AG metadata 0 (40..47) 8 4: 253:16 [48..55]: refcount btree 0 (48..55) 8 5: 253:16 [56..103]: per-AG metadata 0 (56..103) 48 6: 253:16 [104..127]: free space 0 (104..127) 24 ...... BUG: [root@fedora ~]# xfs_io -c 'fsmap -vvvv -d 104 107' /mnt [root@fedora ~]# Normally, we should be able to get [104, 107), but we got nothing. The problem is caused by shifting. The query for the problem-triggered scenario is for the missing_owner interval (e.g. freespace in rmapbt/ unknown space in bnobt), which is obtained by subtraction (gap). For this scenario, the interval is obtained by info->last. However, rec_daddr is calculated based on the start_block recorded in key[1], which is converted by calling XFS_BB_TO_FSBT. Then if rec_daddr does not exceed info->next_daddr, which means keys[1].fmr_physical >> (mp)->m_blkbb_log <= info->next_daddr, no records will be displayed. In the above example, 104 >> (mp)->m_blkbb_log = 12 and 107 >> (mp)->m_blkbb_log = 12, so the two are reduced to 0 and the gap is ignored: before calculate ----------------> after shifting 104(st) 107(ed) 12(st/ed) |---------| | sector size block size Resolve this issue by introducing the "end_daddr" field in xfs_getfsmap_info. This records key[1].fmr_physical at the granularity of sector. If the current query is the last, the rec_daddr is end_daddr to prevent missing interval problems caused by shifting. We only need to focus on the last query, because xfs disks are internally aligned with disk blocksize that are powers of two and minimum 512, so there is no problem with shifting in previous queries. After applying this patch, the above problem have been solved: [root@fedora ~]# xfs_io -c 'fsmap -vvvv -d 104 107' /mnt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 253:16 [104..106]: free space 0 (104..106) 3 Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Zizhi Wo --- fs/xfs/xfs_fsmap.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c index 3a30b36779db..4734f8d6303c 100644 --- a/fs/xfs/xfs_fsmap.c +++ b/fs/xfs/xfs_fsmap.c @@ -162,6 +162,7 @@ struct xfs_getfsmap_info { xfs_daddr_t next_daddr; /* next daddr we expect */ /* daddr of low fsmap key when we're using the rtbitmap */ xfs_daddr_t low_daddr; + xfs_daddr_t end_daddr; /* daddr of high fsmap key */ u64 missing_owner; /* owner of holes */ u32 dev; /* device id */ /* @@ -294,6 +295,19 @@ xfs_getfsmap_helper( return 0; } + /* + * For an info->last query, we're looking for a gap between the + * last mapping emitted and the high key specified by userspace. + * If the user's query spans less than 1 fsblock, then + * info->high and info->low will have the same rm_startblock, + * which causes rec_daddr and next_daddr to be the same. + * Therefore, use the end_daddr that we calculated from + * userspace's high key to synthesize the record. Note that if + * the btree query found a mapping, there won't be a gap. + */ + if (info->last && info->end_daddr != LLONG_MAX) + rec_daddr = info->end_daddr; + /* Are we just counting mappings? */ if (info->head->fmh_count == 0) { if (info->head->fmh_entries == UINT_MAX) @@ -946,6 +960,7 @@ xfs_getfsmap( info.next_daddr = head->fmh_keys[0].fmr_physical + head->fmh_keys[0].fmr_length; + info.end_daddr = LLONG_MAX; info.fsmap_recs = fsmap_recs; info.head = head; @@ -966,8 +981,10 @@ xfs_getfsmap( * low key, zero out the low key so that we get * everything from the beginning. */ - if (handlers[i].dev == head->fmh_keys[1].fmr_device) + if (handlers[i].dev == head->fmh_keys[1].fmr_device) { dkeys[1] = head->fmh_keys[1]; + info.end_daddr = dkeys[1].fmr_physical; + } if (handlers[i].dev > head->fmh_keys[0].fmr_device) memset(&dkeys[0], 0, sizeof(struct xfs_fsmap));