Hi,

On 2021-01-24 01:59:05 +0000, Al Viro wrote:

On Sat, Jan 23, 2021 at 03:50:55PM -0800, Andres Freund wrote:

quoted

As there's only a shared lock, seems like both would end up with the
same ctx->pos and end up updating f_pos to the same offset (assuming the
same count).

Am I missing something?

This:
        f = fdget_pos(fd);
        if (!f.file)
                return -EBADF;
in the callers.

Ah. Thanks for the explainer, userspace guy here ;). I hadn't realized
that fdget_pos acquired a lock around the position...

Regards,

Andres