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Date:   Sat, 3 Sep 2022 01:06:00 +0100
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     NeilBrown <neilb@suse.de>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Daire Byrne <daire@dneg.com>,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Chuck Lever <chuck.lever@oracle.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 01/10] VFS: support parallel updates in the one directory.
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On Mon, Aug 29, 2022 at 11:59:02AM +1000, NeilBrown wrote:

> > When would we get out of __lookup_hash() with in-lookup dentry?
> > Confused...
> 
> Whenever wq is passed in and ->lookup() decides, based on the flags, to do
> nothing.
> NFS does this for LOOKUP_CREATE|LOOKUP_EXCL and for LOOKUP_RENAME_TARGET

Frankly, I would rather do what all other callers of ->lookup() do and
just follow it with d_lookup_done(dentry), no matter what it returns.
It's cheap enough...