[quotemstr]

Doesn't it? https://sambaxp.org/archive-data-samba/sxp09/SambaXP2009-DAT...

It would be weird, even for AIX, to support POSIX byte range locks and not the much simpler flock.

[denotational]

It doesn't, at least on the version I have access to, as it is configured on that cluster.

I’m using Linux rather than AIX.

fcntl(2) locks are supported (as long as they aren't OFD), but flock(2) locks don't work across nodes.