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Message-ID: <b76672d52ffe498259181688eaf54ec75be449e8.camel@kernel.org>
Subject: Re: [PATCH] fs/locks: print full locks information
From:   Jeff Layton <jlayton@kernel.org>
To:     Al Viro <viro@zeniv.linux.org.uk>,
        Luo Longjun <luolongjun@huawei.com>
Cc:     bfields@fieldses.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, sangyan@huawei.com,
        luchunhua@huawei.com
Date:   Sun, 21 Feb 2021 13:43:03 -0500
In-Reply-To: <YDKP0XdT1TVOaGnj@zeniv-ca.linux.org.uk>
References: <20210220063250.742164-1-luolongjun@huawei.com>
         <YDKP0XdT1TVOaGnj@zeniv-ca.linux.org.uk>
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On Sun, 2021-02-21 at 16:52 +0000, Al Viro wrote:
> On Sat, Feb 20, 2021 at 01:32:50AM -0500, Luo Longjun wrote:
> > ?
> > 
> > @@ -2844,7 +2845,13 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
> > ?	if (fl->fl_file != NULL)
> > ?		inode = locks_inode(fl->fl_file);
> > ?
> > 
> > -	seq_printf(f, "%lld:%s ", id, pfx);
> > +	seq_printf(f, "%lld: ", id);
> > +	for (i = 1; i < repeat; i++)
> > +		seq_puts(f, " ");
> > +
> > +	if (repeat)
> > +		seq_printf(f, "%s", pfx);
> 
> RTFCStandard(printf, %*s), please
> 
> > +static int __locks_show(struct seq_file *f, struct file_lock *fl, int level)
> > +{
> > +	struct locks_iterator *iter = f->private;
> > +	struct file_lock *bfl;
> > +
> > +	lock_get_status(f, fl, iter->li_pos, "-> ", level);
> > +
> > +	list_for_each_entry(bfl, &fl->fl_blocked_requests, fl_blocked_member)
> > +		__locks_show(f, bfl, level + 1);
> 
> Er...  What's the maximal depth, again?  Kernel stack is very much finite...

Ooof, good point. I don't think there is a maximal depth on the tree
itself. If you do want to do something like this, then you'd need to
impose a hard limit on the recursion somehow.
-- 
Jeff Layton <jlayton@kernel.org>