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Date: Tue, 21 Oct 2025 10:57:11 -0700
From: "Darrick J. Wong" <djwong@kernel.org>
To: Christoph Hellwig <hch@infradead.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: <20251021175711.GJ3356773@frogsfrogsfrogs>
References: <20251015050133.GV6188@frogsfrogsfrogs>
 <20251016162520.GB3356773@frogsfrogsfrogs>
 <aPHYl6uFyxQjhwP5@infradead.org>
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In-Reply-To: <aPHYl6uFyxQjhwP5@infradead.org>

On Thu, Oct 16, 2025 at 10:48:07PM -0700, Christoph Hellwig wrote:
> > +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.

Done.

--D