Date: Tue, 5 Dec 2017 20:52:54 -0800
From: Matthew Wilcox <willy@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>,
        Ross Zwisler <ross.zwisler@linux.intel.com>,
        Jens Axboe <axboe@kernel.dk>, Rehas Sachdeva <aquannie@gmail.com>,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, linux-nilfs@vger.kernel.org,
        linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 72/73] xfs: Convert mru cache to XArray
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On Tue, Dec 05, 2017 at 08:45:49PM -0800, Matthew Wilcox wrote:
> The dquot code is just going to have to live with the fact that there's
> additional locking going on that it doesn't need.  I'm open to getting
> rid of the irqsafety, but we can't give up the spinlock protection
> without giving up the RCU/lockdep analysis and the ability to move nodes.
> I don't suppose the dquot code can 

Oops, thought I'd finished writing this paragraph.

I don't suppose the dquot code can be restructured to use the xa_lock to
protect, say, qi_dquots?  I suspect not, since you wouldn't know which
of the three xarray locks to use.