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Date: Mon, 16 Oct 2023 22:57:45 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Andrey Albershteyn <aalbersh@redhat.com>, linux-xfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, fsverity@lists.linux.dev,
	djwong@kernel.org, david@fromorbit.com, dchinner@redhat.com,
	willy@infradead.org
Subject: Re: [PATCH v3 07/28] fsverity: always use bitmap to track verified
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On Thu, Oct 12, 2023 at 12:27:46AM -0700, Eric Biggers wrote:
> Currently there are two options: PG_checked and the separate bitmap.  I'm not
> yet convinced that removing the support for the PG_checked method is a good
> change.  PG_checked is a nice solution for the cases where it can be used; it
> requires no extra memory, no locking, and has no max file size.  Also, this
> change seems mostly orthogonal to what you're actually trying to accomplish.

Given that willy has been on a (IMHO reasonable) quest to kill off
as many as possible page flags I'd really like to seize the opportunity
and kill PageCheck in fsverity.  How big are the downsides of the bitmap
vs using the page flags, and do they matter in practice?