MIME-Version: 1.0
From: David Drysdale <drysdale@google.com>
Date: Tue, 18 Nov 2014 13:13:51 +0000
Message-ID: <CAHse=S_EY3mJ_pdZf+A46joro_uNy=6tXGG1v7Va4NX_YxJu2w@mail.gmail.com>
Subject: sparc: Clashing values for O_PATH and FMODE_NONOTIFY?
To: Alexander Viro <viro@zeniv.linux.org.uk>,
        David Miller <davem@davemloft.net>, Eric Paris <eparis@redhat.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        sparclinux@vger.kernel.org, inux-fsdevel@vger.kernel.org
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org

Hi folks,

It looks like the value for O_PATH on sparc:

  arch/sparc/include/uapi/asm/fcntl.h:37:#define O_PATH 0x1000000

clashes with the arch-independent value for __FMODE_NONOTIFY:

  include/linux/fs.h:137:#define FMODE_NONOTIFY ((__force fmode_t)0x1000000)
  include/linux/fs.h:2764:#define __FMODE_NONOTIFY ((__force int)
FMODE_NONOTIFY)

and they are both in the same numbering space, as indicated by the
comment at the top of include/uapi/asm-generic/fcntl.h and the use in
fs/notify/fanotify/fanotify_user.c:715.

Presumably this could theoretically cause problems (no notifications for
O_PATH files on SPARC?), so would it be a good idea to renumber
FMODE_NONOTIFY?  (I *think* that value is entirely kernel-internal.)

Given that this has happened before (12ed2e36c98aec6c4155 "fanotify:
FMODE_NONOTIFY and __O_SYNC in sparc conflict") it would probably
also be a good idea to add __FMODE_NOTIFY to the uniqueness check in
fs/fcntl.c:fcntl_init().

Thoughts?

(I can generate a speculative patch if this is wrong and needs fixing, but I
won't be able to do much about testing it.)

David
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