From: jon ernst <jonernst07@gmail.com>
Subject: Re: [PATCH] ext4: fix a bug when we try to open a file with O_TMPFILE flag
Date: Tue, 23 Jul 2013 13:39:39 +0000
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> Ah, actually I used the following program to hit the bug.  Just for your
> information.  Please let me know if you have any question.
>
> Regards,
>                                                 - Zheng
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
>
> #include <unistd.h>
> #include <sys/types.h>
> #include <fcntl.h>
>
> #define __O_TMPFILE     020000000
> #define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
>
> int main(int argc, char *argv[])
> {
>         int fd;
>
>         fd = open(argv[1], O_RDWR|O_TMPFILE);
>         if (fd < 0) {
>                 perror("open ");
>                 return -1;
>         }
>         close(fd);
>         return 0;
> }

Thank you Zheng!  Pardon if this is a dumb question: why do we need to
manually define "O_TMPFILE"? Not like "O_APPEND" etc. ?  I saw it has
been defined in header file. (fcntl.h) Did I miss anything?

Thanks!