Excerpts from mail: 29-Oct-92 Re: Write Lock and AFS
[EMAIL PROTECTED] (2432)
> There is still a race between open and lock, but it's not as big.
> Somebody else could get a lock,append,close in there on you.
> I think you have to do something more like:
> fd1 = open (READ) -- can't be RDWR because of AFS consistency semantics
> flock(fd1, EXCLUSIVE) -- so nobody else can write it
> fd2 = open (RDWR)
> append(fd2, some stuff)
> close(fd2);
> flock(fd1, UNLOCK)
> close(fd1);
Hey, thanks Lyle, that's just what I needed.
Quite a brilliant little solution: to open two file descriptors. Use
one to establish that this process owns the lock, then the other to open
and append the current version of the file. I can't say I understand
the "AFS consistency semantics" issue you referred to, but I can see how
this should work.
I gave it a try and it seems to work great. Thanks a lot, you made my day.
Kris Davis ([EMAIL PROTECTED], krisd@rchland, krisd@rchvmw2)
Microcode Development Environment Dept213
1-507-253-3707 IBM Rochester, MN
