GNU bug report logs - #13807
The lock for 'DIR/FILE' should always be 'DIR/.#FILE'.

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Message #26 received at 13807 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 13807 <at> debbugs.gnu.org
Subject: Re: bug#13807: updated version to avoid MS-Windows vs non-MS-Windows
	clashes
Date: Sat, 02 Mar 2013 14:37:29 -0800

[Message part 1 (text/plain, inline)]

On 03/02/2013 01:17 PM, Eli Zaretskii wrote:
> Can you describe your testing
> in more details, and what versions of NFS and Windows did you use?

Sure, I created a MS-Windows style lock file .#FILE by hand, then
edited FILE with a GNU/Linux Emacs.  I didn't build the MS-Windows
Emacs, and didn't need to use NFS to reproduce the problem.

There's another issue: a GNU/Linux Emacs might be using an
MS-Windows file system that does not support symbolic links.  Such
an Emacs should use a regular-file lock, just as MS-Windows Emacs does,
which means that the code to create regular-file locks should be implementable
in POSIXish primitives.  Also, locking should work even if the Emacs
instance that created a lock uses a symlink whereas the Emacs instance
trying to get the lock would use a regular file, or vice versa.

It'll take some thinking to get all this to work well.  I've written
a first cut for this and have attached it.  I have not tested this
on MS-Windows at all, and haven't tested it as much as I'd like on
GNU/Linux, but it should give a feel for the sort of changes that
need to be made.  Unfortunately the patch is a bit complicated,
but to some extent this is inherent in such a complicated area.

[filelock2.txt (text/plain, attachment)]

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