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Date: Wed, 9 Dec 2015 09:21:43 -0800
From: Liu Bo <bo.li.liu@oracle.com>
To: "Wang, Zhiye" <Zhiye.Wang@Arcserve.com>
Cc: "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: freeze_bdev and scrub/re-balance
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On Sat, Dec 05, 2015 at 09:57:18AM +0000, Wang, Zhiye wrote:
> Hi all,
> 
> 
> If I understand it correctly, defragment operation is done in user space tools, while scrub/re-balance is done in kernel thread.

Defragment is done via a IOCTL, so it also works in the kernel.

> 
> 
> So, if my kernel module calls freeze_bdev when scrub/re-balance is in progress, will I still be able to get a consistent file system state?

It should be like that with COW enabled.

Thanks,

-liubo