linux-kernel - Re: [PATCH] ubifs: Fix inode leak in xattr code

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Message-ID: <52804b9a-5914-4ac8-571c-c128912cbf14@nod.at>
Date:   Mon, 15 May 2017 18:22:24 +0200
From:   Richard Weinberger <richard@....at>
To:     dedekind1@...il.com, linux-mtd@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, adrian.hunter@...el.com,
        stable@...r.kernel.org
Subject: Re: [PATCH] ubifs: Fix inode leak in xattr code

Artem,

Am 15.05.2017 um 18:05 schrieb Artem Bityutskiy:
> On Mon, 2017-05-15 at 17:22 +0200, Richard Weinberger wrote:
>> Alternatively we could add a iget_locked/drop_nlink/iput sequence to
>> ubifs_tnc_remove_ino(). But that will make unlink() much slower for
>> files
>> that contain xattrs.
> 
> At that level we'd need to do it for every xattr, even those that were
> never be accessed, which would be slow indeed.
> 
> But we really only need to check the inode cache: hey, icache, I am
> dying, and if you have any of my guys (xattrs), I want them to die with
> me. 
> 
> So the question is how to find our guys in the inode cache. I am not
> sure. Probably be we'd have to have our own list of cached inodes in
> the host inode, and maintain it.

Before we try to be clever and implement that, let me benchmark the current
approach.
Debugging leaking inodes is no fun and I'd like to avoid that for a second
time. ;-)

Thanks,
//richard