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Date: Thu, 16 Oct 2025 22:48:07 -0700
From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Carlos Maiolino <cem@kernel.org>, linux-kernel@vger.kernel.org,
	linux-xfs@vger.kernel.org,
	Oleksandr Natalenko <oleksandr@natalenko.name>,
	Pavel Reichl <preichl@redhat.com>, Vlastimil Babka <vbabka@suse.cz>,
	Thorsten Leemhuis <linux@leemhuis.info>
Subject: Re: [PATCH 4/3] xfs: fix locking in xchk_nlinks_collect_dir
Message-ID: <aPHYl6uFyxQjhwP5@infradead.org>
References: <20251015050133.GV6188@frogsfrogsfrogs>
 <20251016162520.GB3356773@frogsfrogsfrogs>
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> +static uint
> +xchk_nlinks_ilock_dir(
> +	struct xfs_inode	*ip)
> +{
> +	uint			lock_mode = XFS_ILOCK_SHARED;
> +
> +	if (xfs_need_iread_extents(&ip->i_df))
> +		lock_mode = XFS_ILOCK_EXCL;
> +
> +	if (xfs_has_parent(ip->i_mount) && xfs_inode_has_attr_fork(ip) &&
> +	    xfs_need_iread_extents(&ip->i_af))
> +		lock_mode = XFS_ILOCK_EXCL;

Please add a comment explaining the need for the conditions, this is too
much black magic otherwise.