Hi monks,

I'm working on some code that needs to do file locking over NFS using fcntl(). Flock won't work because of Red Hat deciding to remove flock() support from their NFS client in Red Hat Enterprise Linux 3 (see this recent thread). One thing I'm seeing different between fcntl() and flock() is the way they handle multiple locks on the same file. For instance:

Say I open a filehandle and get a F_RDLCK on it to prevent anyone else from writing to the file. I later call up a subroutine which also opens the file and puts a F_RDLCK on it, does something, then closes it's handle. With flock(), the original file handle still has a lock on the file. With fcntl(), closing the second filehandle clears both of the locks, so the file is now completely unlocked.

Is there a good way of making fcntl behave more like flock()? In other words, is there a way to do file locking over NFS with fcntl() in which when multiple handles are opened on the same file, closing one handle doesn't clear everyone else's locks?

In reply to Fcntl() and multiple filehandles by Anonymous Monk

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