Bug 85381

* How to reproduce:

/tmp % cat a.c
#define _GNU_SOURCE 1
#include <limits.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>

int main(void)
{
        int pipefd[2];
        pipe(pipefd);

        for (;;) {
                sleep(1);
                write(pipefd[1], "Hello world\n", 12);
                splice(pipefd[0], NULL, 1, NULL, INT_MAX, 0);
        }
}
/tmp % gcc a.c
/tmp % touch a.txt
/tmp % ./a.out > a.txt & tail -f a.txt


* Expected result:

tail prints "Hello world" every second.



* Actual result:

btrfs: Works as expected;
ext4/tmpfs: tail blocks on inotify forever and prints nothing.