linux-kernel - Re: [PATCH] nfsd: Make creates return EEXIST correctly instead of EPERM

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Message-ID: <20160709025230.GR14480@ZenIV.linux.org.uk>
Date:	Sat, 9 Jul 2016 03:52:30 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Oleg Drokin <green@...uxhacker.ru>
Cc:	Jeff Layton <jlayton@...chiereds.net>,
	"J. Bruce Fields" <bfields@...ldses.org>,
	linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] nfsd: Make creates return EEXIST correctly instead of
 EPERM

On Fri, Jul 08, 2016 at 11:59:50AM -0400, Oleg Drokin wrote:

> "If path names a symbolic link, mkdir() shall fail and set errno to [EEXIST]."
> 
> This sounds pretty straightforward to me, no?
> Since it does not matter that we do not have write permissions here, because
> the name already exists.

When more than one condition applies, we have every right to return any of
them.  POSIX does *NOT* specify the order of checks.  Never had.