linux-kernel - Re: Question on fscrypt_d_revalidate() and fstest generic/429

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Date:   Tue, 16 May 2017 13:22:44 +0200
From:   Richard Weinberger <richard@....at>
To:     Al Viro <viro@...IV.linux.org.uk>
Cc:     Eric Biggers <ebiggers3@...il.com>, linux-fscrypt@...r.kernel.org,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Eric Biggers <ebiggers@...gle.com>,
        Theodore Ts'o <tytso@....edu>,
        David Gstir <david@...ma-star.at>,
        David Oberhollenzer <david.oberhollenzer@...ma-star.at>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        Artem Bityutskiy <dedekind1@...il.com>,
        Adrian Hunter <adrian.hunter@...el.com>
Subject: Re: Question on fscrypt_d_revalidate() and fstest generic/429

Al,

Am 16.05.2017 um 01:50 schrieb Al Viro:
> On Mon, May 15, 2017 at 09:51:03PM +0200, Richard Weinberger wrote:
> 
>>> I doubt it's the right solution to make fscrypt_d_revalidate() look at
>>> ->i_nlink, since ->d_revalidate() is meant to validate the filename, not the
>>> inode.  I think there is probably a VFS bug that is causing the dentries to not
>>> be freed.
>>
>> Not sure. Al? :-)
> 
> What's to tell VFS that they are garbage?  If your code doesn't do it,
> VFS has no way to know.  And I certainly agree that using ->d_revalidate()
> to trigger their unhashing is a bloody odd design; take it up with whoever
> had come up with it...

Not sure whether I understood your answer.
What is the preferred way to inform VFS that the dentry is no longer valid?

Thanks,
//richard