Messages in this thread | | | Subject | Re: file locking over NFS in 2.2.7 | From | Trond Myklebust <> | Date | 09 May 1999 22:11:03 +0200 |
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Pavel Khaustov <khaustov@andrew.cmu.edu> writes:
> elm and mutt fail when they use fcntl() to lock the mail spool file which > is mounted over NFS in our case (/var/spool/mail served by SunOS 4.1.3 and > mounted by Linux clients). strace shows that after fcntl() the variable > errno is set to "No locks available". It worked when 2.0.36 kernel was > used. It also works from SunOS clients. > > On Linux side: kernel 2.2.7, latest userland nfsd, lockd is compiled into > the kernel. A test program showed that Linux-Linux locking didn't work > either. > > Can someone explain it or point to relevant information sources? >
File locking is not supported by the userland nfsd. If you want true file locking, use knfsd. 2.0.x kernels supported local file locks only: this is why they 'worked' (not at all), and 2.2.x will do the same if you use the 'nolock' mount option.
In other words: Always compile mutt/elm/pine etc to use dotlocking or some such workaround when you think you might want to use the userland nfsd or a 2.0.x kernel, since posix file locking will never be reliable in that case. (BSD file locking is not supported for 2.2.x either.)
Cheers, Trond
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