From: Anand Jain <Anand.Jain@oracle.com>
To: miaox@cn.fujitsu.com
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 3/4] btrfs: fix rw_devices miss match after seed replace
Date: Tue, 12 Aug 2014 16:00:05 +0800 [thread overview]
Message-ID: <53E9C985.2040007@oracle.com> (raw)
In-Reply-To: <53E9C267.4020902@cn.fujitsu.com>
On 12/08/2014 15:29, Miao Xie wrote:
> On Mon, 11 Aug 2014 17:42:55 +0800, Anand Jain wrote:
>> reproducer:
>> reproducer:
>> mount /dev/sdb /btrfs
>> btrfs dev add /dev/sdc /btrfs
>> btrfs rep start -B /dev/sdb /dev/sdd /btrfs
>> umount /btrfs
>>
>> WARNING: CPU: 0 PID: 3882 at fs/btrfs/volumes.c:892 __btrfs_close_devices+0x1c8/0x200 [btrfs]()
>>
>> which is
>>
>> WARN_ON(fs_devices->rw_devices);
>>
>> The problem here is that we did not add one to the rw_devices when
>> we replace the seed device with a writable device.
>>
>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>> ---
>> fs/btrfs/dev-replace.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
>> index eea26e1..fb0a7fa 100644
>> --- a/fs/btrfs/dev-replace.c
>> +++ b/fs/btrfs/dev-replace.c
>> @@ -562,6 +562,8 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
>> if (fs_info->fs_devices->latest_bdev == src_device->bdev)
>> fs_info->fs_devices->latest_bdev = tgt_device->bdev;
>> list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
>> + if (src_device->fs_devices->seeding)
>> + fs_info->fs_devices->rw_devices++;
>
> As I said in the previous version of this patch, we might increase ->rw_devices twice if
> the source device is a missing device in the seed filesystem. Once is here, the other is
> in btrfs_rm_dev_replace_srcdev().
Yes that should be fixed. I think a separate patch will do since
btrfs_rm_dev_replace_srcdev() is invariably incrementing the
->rw_devices without checking if the fs is a seed fs.
Anand
> Thanks
> Miao
>
>>
>> /* replace the sysfs entry */
>> btrfs_kobj_rm_device(fs_info, src_device);
>>
>
> --
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>
next prev parent reply other threads:[~2014-08-12 8:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-11 9:42 [PATCH 1/4] btrfs: preparatory to make btrfs_rm_dev_replace_srcdev() seed aware Anand Jain
2014-08-11 9:42 ` [PATCH 2/4] btrfs: replace seed device followed by unmount causes kernel WARNING Anand Jain
2014-08-12 7:27 ` Miao Xie
2014-08-11 9:42 ` [PATCH 3/4] btrfs: fix rw_devices miss match after seed replace Anand Jain
2014-08-12 7:29 ` Miao Xie
2014-08-12 8:00 ` Anand Jain [this message]
2014-08-11 9:42 ` [PATCH 4/4] btrfs: update sprout seed pointer when seed fs is relinquished Anand Jain
2014-08-12 7:24 ` Miao Xie
2014-08-12 7:56 ` Anand Jain
2014-08-12 7:30 ` [PATCH 1/4] btrfs: preparatory to make btrfs_rm_dev_replace_srcdev() seed aware Miao Xie
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