Re: [PATCH 2/3] fd/locks: allow get the lock owner by F_OFD_GETLK

[stsp]

20.06.2023 17:02, Jeff Layton пишет:
> Suppose I start a process (call it pid 100), and then spawn a thread
> (101). I then have 101 open a file and set an OFD lock on it (such that
> the resulting fl_pid field in the file_lock is set to 101).

How come?
There are multiple places in locks.c
with this line:
fl->fl_pid = current->tgid;

And I've yet to see the line like:
fl->fl_pid = current->pid;
Its simply not there.

No, we put tgid into l_pid!
tgid will still be 100, no matter how
many threads you spawn or destroy.
Or what am I misseng?


> That's just one example, of course. The underlying problem is that OFD
> locks are not owned by processes in the same way that traditional POSIX
> locks are, so reporting a pid there is unreliable, at best.
But we report tgid.
It doesn't depend on threads.
I don't understand. :)