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Subject: Re: [PATCH 1/2] Block layer filter - second version
To:     Sergei Shtepa <sergei.shtepa@veeam.com>, axboe@kernel.dk,
        viro@zeniv.linux.org.uk, hch@infradead.org,
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        johannes.thumshirn@wdc.com, ming.lei@redhat.com, jack@suse.cz,
        tj@kernel.org, gustavo@embeddedor.com, bvanassche@acm.org,
        osandov@fb.com, koct9i@gmail.com, damien.lemoal@wdc.com,
        steve@sk2.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        linux-mm@kvack.org
References: <1603271049-20681-1-git-send-email-sergei.shtepa@veeam.com>
 <1603271049-20681-2-git-send-email-sergei.shtepa@veeam.com>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <7bd31238-0c7c-ed6f-d0b9-680fcaa54513@infradead.org>
Date:   Wed, 21 Oct 2020 08:09:18 -0700
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On 10/21/20 2:04 AM, Sergei Shtepa wrote:
> diff --git a/block/Kconfig b/block/Kconfig
> index bbad5e8bbffe..a308801b4376 100644
> --- a/block/Kconfig
> +++ b/block/Kconfig
> @@ -204,6 +204,17 @@ config BLK_INLINE_ENCRYPTION_FALLBACK
>  	  by falling back to the kernel crypto API when inline
>  	  encryption hardware is not present.
>  
> +config BLK_FILTER
> +	bool "Enable support for block layer filters"
> +	default y

Drop the default y. We don't add modules to a default build without
some tough justification.

> +	depends on MODULES
> +	help
> +	  Enabling this lets third-party kernel modules intercept

	                lets loadable kernel modules intercept

> +	  bio requests for any block device. This allows them to implement
> +	  changed block tracking and snapshots without any reconfiguration of
> +	  the existing setup. For example, this option allows snapshotting of
> +	  a block device without adding it to LVM.


-- 
~Randy