Re: [PATCH v4 1/3] hfsplus: fix to update ctime after rename

[Al Viro <viro@zeniv.linux.org.uk>]

On Wed, Jul 23, 2025 at 05:58:01PM +0000, Viacheslav Dubeyko wrote:

> So, this line simply copies CNID from old_dentry->d_fsdata to
> new_dentry->d_fsdata during the rename operation. I assume that
> ->fs_data should be untouched by generic logic of dentries processing.

Yes, I understand that; what I do not understand is why.  Why would
the CNID of renamed object be slapped on dentry of removed target?
I'm trying to understand the logics with link(2) and unlink-of-opened
in that code...

Incidentally, what happens if you
	fd = creat("foo", 0666);
	write(fd, "foo", 3);
	link("foo", "bar");
	unlink("bar");
	close(fd);
The games with S_DEAD in there look odd...