Re: locking against myself in unionfs code

[David Holland <dholland-tech%netbsd.org@localhost>]

On Wed, Sep 03, 2025 at 04:47:34PM +0200, Edgar Fu? wrote:
 > Thanks for the fast analysis!

:-)

 > > another process did the same link() operation
 >
 > I doubt another process was doing anything on that file system.
 > 
 > What I was running was a borg extract on a work dir which had union-mounted 
 > below (mount_union -b) a borg extract-ion of an older archive. I doubt borg 
 > does anything multi-threaded and I wasn't running anything else on that 
 > development server at that time.

It's conceivable that there's a path involving the copyup step and
whiteouts that also causes the file to appear, which would then
exhibit the same symptoms.

Also, it's possible that I didn't fix it, so if you see it again be
sure to post more :-)

(The thing I found was _a_ bug, but might not be _the_ bug; it's not
like they're rare in onionfs)

-- 
David A. Holland
dholland%netbsd.org@localhost