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Date: Mon, 19 Jan 2026 10:27:48 +0100
From: Christoph Hellwig <hch@lst.de>
To: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>, Eric Biggers <ebiggers@kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Christian Brauner <brauner@kernel.org>,
	David Sterba <dsterba@suse.com>, Theodore Ts'o <tytso@mit.edu>,
	Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <chao@kernel.org>,
	Andrey Albershteyn <aalbersh@redhat.com>,
	linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org,
	linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net,
	fsverity@lists.linux.dev
Subject: Re: [PATCH 4/6] fsverity: use a hashtable to find the fsverity_info
Message-ID: <20260119092748.GA10125@lst.de>
References: <20260119062250.3998674-1-hch@lst.de> <20260119062250.3998674-5-hch@lst.de> <z4652hoxetll645hgpfuhy3pogm5y32ealgydlaz4kwve6qc2g@bl6ilzut2ybp>
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On Mon, Jan 19, 2026 at 10:21:00AM +0100, Jan Kara wrote:
> OK, but since __fsverity_get_info() is just rhashtable_lookup_fast() what
> prevents the CPU from reordering the hash table reads before the S_VERITY
> check? I think you need a barrier in fsverity_get_info() to enforce the
> proper ordering. The matching ordering during setting of S_VERITY is
> implied by cmpxchg used to manipulate i_flags so that part should be fine.

Yes, probably.