Poettering: Revisiting how we put together Linux systems

Posted Sep 9, 2014 15:27 UTC (Tue) by bfields (subscriber, #19510)
In reply to: Poettering: Revisiting how we put together Linux systems by foom
Parent article: Poettering: Revisiting how we put together Linux systems

Huh. A freebsd man page agrees with you:

https://www.freebsd.org/cgi/man.cgi?query=flock&sektion=2
If a file is locked by a process through flock(), any record within the file will be seen as locked from the viewpoint of another process using fcntl(2) or lockf(3), and vice versa.

Recent linux's flock(2) suggests the Linux behavior was an attempt to match BSD behavior that has since changed?:

http://man7.org/linux/man-pages/man2/flock.2.html
Since kernel 2.0, flock() is implemented as a system call in its own right rather than being emulated in the GNU C library as a call to fcntl(2). This yields classical BSD semantics: there is no interaction between the types of lock placed by flock() and fcntl(2), and flock() does not detect deadlock. (Note, however, that on some modern BSDs, flock() and fcntl(2) locks do interact with one another.)

Strange. In any case, changing the local Linux behavior is probably out of the question at this point.