Re: [PATCH 5/6] xfs: don't modify file attributes or poke fsnotify for dry runs

[Christoph Hellwig <hch@infradead.org>]

On Wed, Aug 12, 2026 at 10:26:43PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> LOLLM points out that a dry run shouldn't poke fsnotify because we don't
> actually change the files.  I noticed that we also shouldn't be removing
> file privileges when doing a dry run.

> +++ b/fs/xfs/xfs_exchrange.c
> @@ -701,6 +701,9 @@ xfs_exchrange_contents(
>  	if (error)
>  		goto out_unlock;
>  
> +	if (fxr->flags & XFS_EXCHANGE_RANGE_DRY_RUN)
> +		goto out_unlock;
> +
>  	/*
>  	 * Finish the exchange by removing special file privileges like any
>  	 * other file write would do.  This may involve turning on support for

This just skip removing the privileges.  I guess the commit mentions
this on the side, but this is probably the important part, so my
emphasis it?  It would also seem easier to move the check into
xfs_exchange_range_finish next to the code that it guards.

> @@ -783,6 +786,9 @@ xfs_exchange_range(
>  	if (ret)
>  		return ret;
>  
> +	if (fxr->flags & XFS_EXCHANGE_RANGE_DRY_RUN)
> +		return 0;
> +
>  	fsnotify_modify(fxr->file1);
>  	if (fxr->file2 != fxr->file1)
>  		fsnotify_modify(fxr->file2);

Move the fsnotify calls into an if statement instead of the
early return?