From patchwork Mon Apr 27 07:34:13 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anand Jain X-Patchwork-Id: 6278621 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 8D31F9F313 for ; Mon, 27 Apr 2015 07:37:24 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B409C2020F for ; Mon, 27 Apr 2015 07:37:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8874203B5 for ; Mon, 27 Apr 2015 07:37:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932282AbbD0HhU (ORCPT ); Mon, 27 Apr 2015 03:37:20 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:28398 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932137AbbD0HhI (ORCPT ); Mon, 27 Apr 2015 03:37:08 -0400 Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id t3R7b3Zi014112 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 27 Apr 2015 07:37:04 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserv0021.oracle.com (8.13.8/8.13.8) with ESMTP id t3R7b3PY005750 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Mon, 27 Apr 2015 07:37:03 GMT Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by aserv0122.oracle.com (8.13.8/8.13.8) with ESMTP id t3R7b3lq021546; Mon, 27 Apr 2015 07:37:03 GMT Received: from OL.sg.oracle.com (/10.186.101.34) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 27 Apr 2015 00:37:03 -0700 From: Anand Jain To: linux-btrfs@vger.kernel.org Cc: dsterba@suse.cz, m_btrfs@ml1.co.uk Subject: [PATCH 6/8] Btrfs: add btrfs_read_dev_one_super() to read one specific SB Date: Mon, 27 Apr 2015 15:34:13 +0800 Message-Id: <1430120055-10381-7-git-send-email-anand.jain@oracle.com> X-Mailer: git-send-email 2.0.0.153.g79dcccc In-Reply-To: <1430120055-10381-1-git-send-email-anand.jain@oracle.com> References: <1429525756-2727-2-git-send-email-anand.jain@oracle.com> <1430120055-10381-1-git-send-email-anand.jain@oracle.com> X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This uses a chunk of code from btrfs_read_dev_super() and creates a function called btrfs_read_dev_one_super() so that next patch can use it for scratch superblock. Signed-off-by: Anand Jain --- fs/btrfs/disk-io.c | 54 ++++++++++++++++++++++++++++++++++-------------------- fs/btrfs/disk-io.h | 2 ++ 2 files changed, 36 insertions(+), 20 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index f47c643..3681e1e 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3085,6 +3085,37 @@ static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate) put_bh(bh); } +int btrfs_read_dev_one_super(struct block_device *bdev, int copy_num, + struct buffer_head **bh) +{ + struct buffer_head *bufhead; + struct btrfs_super_block *super; + u64 bytenr; + + bytenr = btrfs_sb_offset(copy_num); + if (bytenr + BTRFS_SUPER_INFO_SIZE >= i_size_read(bdev->bd_inode)) + return -EINVAL; + + bufhead = __bread(bdev, bytenr / 4096, BTRFS_SUPER_INFO_SIZE); + /* + * If we fail to read from the underlaying drivers, as of now + * the best option we have is to mark it EIO. + */ + if (!bufhead) + return -EIO; + + super = (struct btrfs_super_block *)bufhead->b_data; + if (btrfs_super_bytenr(super) != bytenr || + btrfs_super_magic(super) != BTRFS_MAGIC) { + brelse(bufhead); + return -EINVAL; + } + + *bh = bufhead; + return 0; +} + + struct buffer_head *btrfs_read_dev_super(struct block_device *bdev) { struct buffer_head *bh; @@ -3092,7 +3123,6 @@ struct buffer_head *btrfs_read_dev_super(struct block_device *bdev) struct btrfs_super_block *super; int i; u64 transid = 0; - u64 bytenr; int ret = -EINVAL; /* we would like to check all the supers, but that would make @@ -3101,28 +3131,12 @@ struct buffer_head *btrfs_read_dev_super(struct block_device *bdev) * later supers, using BTRFS_SUPER_MIRROR_MAX instead */ for (i = 0; i < 1; i++) { - bytenr = btrfs_sb_offset(i); - if (bytenr + BTRFS_SUPER_INFO_SIZE >= - i_size_read(bdev->bd_inode)) - break; - bh = __bread(bdev, bytenr / 4096, - BTRFS_SUPER_INFO_SIZE); - /* - * If we fail to read from the underlaying drivers, as of now - * the best option we have is to mark it EIO. - */ - if (!bh) { - ret = -EIO; + + ret = btrfs_read_dev_one_super(bdev, i, &bh); + if (ret) continue; - } super = (struct btrfs_super_block *)bh->b_data; - if (btrfs_super_bytenr(super) != bytenr || - btrfs_super_magic(super) != BTRFS_MAGIC) { - brelse(bh); - ret = -EINVAL; - continue; - } if (!latest || btrfs_super_generation(super) > transid) { brelse(latest); diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h index 27d44c0..36bd1fc 100644 --- a/fs/btrfs/disk-io.h +++ b/fs/btrfs/disk-io.h @@ -60,6 +60,8 @@ void close_ctree(struct btrfs_root *root); int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root *root, int max_mirrors); struct buffer_head *btrfs_read_dev_super(struct block_device *bdev); +int btrfs_read_dev_one_super(struct block_device *bdev, int copy_num, + struct buffer_head **bh); int btrfs_commit_super(struct btrfs_root *root); struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root, u64 bytenr);