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Date: Mon, 9 Feb 2026 07:28:21 +0100
From: hch <hch@lst.de>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>,
	"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
	hch <hch@lst.de>
Subject: Re: [bug report] xfs/802 failure due to mssing fstype report by
 lsblk
Message-ID: <20260209062821.GA9021@lst.de>
References: <aYWobEmDn0jSPzqo@shinmob> <20260206173805.GY7712@frogsfrogsfrogs> <aYlHZ4bBQI3Vpb3N@shinmob> <20260209060716.GL1535390@frogsfrogsfrogs>
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On Sun, Feb 08, 2026 at 10:07:16PM -0800, Darrick J. Wong wrote:
> Waitaminute, how can you even format xfs on nullblk to run fstests?
> Isn't that the bdev that silently discards everything written to it, and
> returns zero on reads??

nullblk can be used with or without a backing store.  In the former
case it will not always return zeroes on reads obviously.