linux-ext4 - Re: [PATCH 16/16] fsverity: use a hashtable to find the fsverity

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Message-ID: <20260128032817.GB2718@sol>
Date: Tue, 27 Jan 2026 19:28:17 -0800
From: Eric Biggers <ebiggers@...nel.org>
To: Christoph Hellwig <hch@....de>
Cc: Al Viro <viro@...iv.linux.org.uk>,
	Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
	David Sterba <dsterba@...e.com>, Theodore Ts'o <tytso@....edu>,
	Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <chao@...nel.org>,
	Andrey Albershteyn <aalbersh@...hat.com>,
	Matthew Wilcox <willy@...radead.org>, linux-fsdevel@...r.kernel.org,
	linux-btrfs@...r.kernel.org, linux-ext4@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net, fsverity@...ts.linux.dev
Subject: Re: [PATCH 16/16] fsverity: use a hashtable to find the fsverity_info

On Mon, Jan 26, 2026 at 05:51:02AM +0100, Christoph Hellwig wrote:
> @@ -296,18 +243,39 @@ static inline bool fsverity_verify_page(struct fsverity_info *vi,
>   * fsverity_active() - do reads from the inode need to go through fs-verity?
>   * @inode: inode to check
>   *
> - * This checks whether the inode's verity info has been set.
> - *
> - * Filesystems call this from ->readahead() to check whether the pages need to
> - * be verified or not.  Don't use IS_VERITY() for this purpose; it's subject to
> - * a race condition where the file is being read concurrently with
> - * FS_IOC_ENABLE_VERITY completing.  (S_VERITY is set before the verity info.)
> + * This checks whether the inode's verity info has been set, and reads need
> + * to verify the verity information.

Nit: the point is to verify the file's data, not to verify "the verity
information".

>   *
>   * Return: true if reads need to go through fs-verity, otherwise false
>   */
> -static inline bool fsverity_active(const struct inode *inode)
> +static __always_inline bool fsverity_active(const struct inode *inode)
> +{
> +	if (IS_ENABLED(CONFIG_FS_VERITY) && IS_VERITY(inode)) {
> +		/*
> +		 * This pairs with the try_cmpxchg in set_mask_bits()
> +		 * used to set the S_VERITY bit in i_flags.
> +		 */
> +		smp_mb();
> +		return true;
> +	}
> +
> +	return false;
> +}

Is there a reason for this function in particular to be __always_inline?
fsverity_get_info() is just inline.

- Eric