umount -f implementation

[David G Lawrence]

> I just noticed that when I do the following:
> - start a large write to an NFS mounted fs
> - network partition the server (unplug a net cable)
> - do a "umount -f <mntpoint>" on the machine
> 
> that it gets stuck trying to write dirty blocks to the server.
> 
> I had, in the past, assumed that a "umount -f" of an NFS mount would be
> used to get rid of an NFS mount on an unresponsive server and that loss
> of "writes in progress" would be expected to happen.
> 
> Does that sound correct? (In other words, an I seeing a bug or a 
> feature?)
> 
> Thanks in advance for any info, rick
> ps: I have a simple "fix" if this is a bug, but I wanted to check before
>     submitting a patch.

   I would say that you are seeing a bug. -f is supposed to mean "force",
of course. Any buffers or outstanding transactions should be terminated
immediately.
   Oh, and most of us know that you, as one of the NFS developers in the
past, well-know the difference between hard and soft NFS mounts. ;-)

-DG

David G. Lawrence
President
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