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Date: Fri, 16 Jan 2026 10:21:38 +0100
From: Christoph Hellwig <hch@lst.de>
To: Namjae Jeon <linkinjeon@kernel.org>
Cc: viro@zeniv.linux.org.uk, brauner@kernel.org, hch@lst.de, tytso@mit.edu,
	willy@infradead.org, jack@suse.cz, djwong@kernel.org,
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	xiang@kernel.org, dsterba@suse.com, pali@kernel.org,
	ebiggers@kernel.org, neil@brown.name, amir73il@gmail.com,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	iamjoonsoo.kim@lge.com, cheol.lee@lge.com, jay.sim@lge.com,
	gunho.lee@lge.com, Hyunchul Lee <hyc.lee@gmail.com>
Subject: Re: [PATCH v5 09/14] ntfs: update runlist handling and cluster
 allocator
Message-ID: <20260116092138.GA21396@lst.de>
References: <20260111140345.3866-1-linkinjeon@kernel.org> <20260111140345.3866-10-linkinjeon@kernel.org>
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User-Agent: Mutt/1.5.17 (2007-11-01)

> +	for (index = start_index; index < end_index; index++) {
> +		folio = filemap_lock_folio(vol->lcnbmp_ino->i_mapping, index);
> +		if (IS_ERR(folio)) {
> +			page_cache_sync_readahead(vol->lcnbmp_ino->i_mapping, ra, NULL,

You probably only want to kick off a read for -ENOENT here, and not
any error?

> +					index, end_index - index);
> +			folio = read_mapping_folio(vol->lcnbmp_ino->i_mapping, index, NULL);
> +			if (!IS_ERR(folio))
> +				folio_lock(folio);
> +		}

either way, this seems like a nice primitive for doing reasonably
efficient reads from the page cache, and I could think of a few
other places to it.  Maybe factor it into helper, even if you keep
it in the ntfs code for now?