Re: [RFC PATCH -v4 00/14] fsnotify, dnotify, and inotify

From: C. Scott Ananian
Date: Thu Dec 25 2008 - 13:18:39 EST


On Mon, Dec 22, 2008 at 6:21 PM, Christoph Hellwig <hch@xxxxxxxxxxxxx> 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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