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Date: Tue, 25 Jul 2017 00:51:56 -0400
From: "Theodore Ts'o" <tytso@mit.edu>
To: Pavel Machek <pavel@ucw.cz>
Cc: Reindl Harald <h.reindl@thelounge.net>, linux-ext4@vger.kernel.org,
        kernel list <linux-kernel@vger.kernel.org>, kent.overstreet@gmail.com,
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Subject: Re: bcache with existing ext4 filesystem
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On Mon, Jul 24, 2017 at 10:04:51PM +0200, Pavel Machek wrote:
> Question for you was... Is the first 1KiB of each ext4 filesystem still
> free and "reserved for a bootloader"?

Yes.

> If I needed more for bcache superblock (8KiB, IIRC), would that be
> easy to accomplish on existing filesystem?

Huh?  Why would the bcache superblock matter when you're talking about
the ext4 layout?  The bcache superblock will be on the bcache
device/partition, and the ext4 superblock will be on the ext4
device/partition.

						- Ted