From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2130.oracle.com ([141.146.126.79]:50982 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726277AbeHBL4i (ORCPT ); Thu, 2 Aug 2018 07:56:38 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w72A3RGp100553 for ; Thu, 2 Aug 2018 10:06:10 GMT Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by aserp2130.oracle.com with ESMTP id 2kge0dapr9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Thu, 02 Aug 2018 10:06:10 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w72A69H8006577 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Thu, 2 Aug 2018 10:06:09 GMT Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w72A694H010293 for ; Thu, 2 Aug 2018 10:06:09 GMT From: Anand Jain To: linux-btrfs@vger.kernel.org Subject: [PATCH v3 4/4] btrfs: add helper btrfs_num_devices() to deduce num_devices Date: Thu, 2 Aug 2018 18:09:34 +0800 Message-Id: <20180802100934.12468-1-anand.jain@oracle.com> In-Reply-To: <20180726065334.30594-5-anand.jain@oracle.com> References: <20180726065334.30594-5-anand.jain@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: When the replace is running the fs_devices::num_devices also includes the replace device, however in some operations like device delete and balance it needs the actual num_devices without the repalce devices, so now the function btrfs_num_devices() just provides that. And here is a scenario how balance and repalce items could co-exist. Consider balance is started and paused, now start the replace followed by a power-recycle of the system. During following mount, the open_ctree() first restarts the balance so it must check for the replace device otherwise our num_devices calculation will be wrong. Signed-off-by: Anand Jain --- v2->v3: update changelog with not so obvious balance and repalce co-existance secnario v1->v2: add comments fs/btrfs/volumes.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index fe74fefc75f7..8844904f9009 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1854,6 +1854,21 @@ void btrfs_assign_next_active_device(struct btrfs_device *device, fs_info->fs_devices->latest_bdev = next_device->bdev; } +/* Returns btrfs_fs_devices::num_devices excluding replace device if any */ +static inline u64 btrfs_num_devices(struct btrfs_fs_info *fs_info) +{ + u64 num_devices = fs_info->fs_devices->num_devices; + + btrfs_dev_replace_read_lock(&fs_info->dev_replace); + if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) { + BUG_ON(num_devices < 1); + num_devices--; + } + btrfs_dev_replace_read_unlock(&fs_info->dev_replace); + + return num_devices; +} + int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path, u64 devid) { @@ -1865,13 +1880,7 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path, mutex_lock(&uuid_mutex); - num_devices = fs_devices->num_devices; - btrfs_dev_replace_read_lock(&fs_info->dev_replace); - if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) { - BUG_ON(num_devices < 1); - num_devices--; - } - btrfs_dev_replace_read_unlock(&fs_info->dev_replace); + num_devices = btrfs_num_devices(fs_info); ret = btrfs_check_raid_min_devices(fs_info, num_devices - 1); if (ret) @@ -3721,13 +3730,8 @@ int btrfs_balance(struct btrfs_fs_info *fs_info, } } - num_devices = fs_info->fs_devices->num_devices; - btrfs_dev_replace_read_lock(&fs_info->dev_replace); - if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) { - BUG_ON(num_devices < 1); - num_devices--; - } - btrfs_dev_replace_read_unlock(&fs_info->dev_replace); + num_devices = btrfs_num_devices(fs_info); + allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE | BTRFS_BLOCK_GROUP_DUP; if (num_devices > 1) allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1); -- 2.7.0