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Message-ID: <c6d9bea0812251017u6a271fc0j5d26b8bbe3407877@mail.gmail.com>
Date: Thu, 25 Dec 2008 13:17:28 -0500
From: "C. Scott Ananian" <cscott@laptop.org>
To: "Christoph Hellwig" <hch@infradead.org>
Subject: Re: [RFC PATCH -v4 00/14] fsnotify, dnotify, and inotify
Cc: "Al Viro" <viro@zeniv.linux.org.uk>, "Eric Paris" <eparis@redhat.com>,
       linux-kernel@vger.kernel.org
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On Mon, Dec 22, 2008 at 6:21 PM, Christoph Hellwig <hch@infradead.org> wrote:
> On Mon, Dec 22, 2008 at 06:08:08PM -0500, C. Scott Ananian wrote:
>> That's not correct, as /proc/self/fd/<num> and the getcwd syscall make
>> clear.
>
> No.  These take a file descriptor into account, which _does_ have a
> unique path.

getcwd doesn't actually hold a file descriptor to the working
directory.  If you reread my message, you'll find that I was explicit
about where the information was stored.

>> struct inode has a i_dentry member, and via its d_parent links
>> you can reconstruct the path, as __d_path in fs/dcache.c does.
>
> reconstruct _a_ path inside the same filesystem, ignoring which link is
> wanted, and inside which mount.

Right.  If you go back and reread my message, I made clear that that
was sufficient.

But Al's question is more relevant, and I'll try to restate the
problem for him, since it's clear that none of the existing *notify
interfaces was written with an eye towards making possible races
easily manageable.
  --scott

-- 
                         ( http://cscott.net/ )
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