bug#37884: 27.0.50; Cannot write to a file in VirtualBox shared directory

[Robert Pluim <rpluim@gmail.com>]

Please keep 37884@debbugs.gnu.org in the CC

>>>>> On Sun, 27 Oct 2019 17:22:12 +1100, Bernardo <bernardo.bacic@pobox.com> said:

    Bernardo> Hi Robert,

    Bernardo> apologies for the late response, i came down with a cold and wasn't
    Bernardo> checking my email;

No worries.

    Bernardo> i have a quick and dirty test along these lines (+ include headers)
    Bernardo> emulating what's happening when a lock is created/removed.
    Bernardo> ,----
    Bernardo> | int main()
    Bernardo> | {
    Bernardo> | 	const char buff[] = "abc";
    Bernardo> | 
    Bernardo> | 	int fd = open( "another_test", O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC, 0600);
    Bernardo> | 	write( fd , buff, 3 );
    Bernardo> | 	fchmod( fd, 0444 );
    Bernardo> | 	close( fd );
    Bernardo> | 	unlink( "another_test" );
    Bernardo> | 	return 0;
    Bernardo> | }
    Bernardo> `----

    Bernardo> as you would expect works fine here (at home) on ext4 file system;
    Bernardo> will try this on work computer (most likely tomorrow) where VirtualBox
    Bernardo> is installed, possibly tweak the file access flags and report the
    Bernardo> results back;

Thanks. I might have a VirtualBox instance lying around, but itʼs
hosted on GNU/Linux, not Windows, so the behaviour is likely to be
different.

    Bernardo> thanks for looking into this

Youʼre welcome.

Eli, if the results come back that using 0664 or similar on lockfiles
resolves this, would you be amenable to such a change?

Robert