Re: New client-side locking implementation

Eric Williams wrote:

> On Tue, 26 Jul 2005, Jeffrey Altman wrote:
> 
> 
>>Matt Benjamin wrote:
>>
>>>1. Does something need to be said about the choice to enforce mandatory
>>>locking?
>>
>>As opposed to the other choice which is to *NOT* enforce mandatory locks?
> 
> 
> another choice is to enforce locking in an advisory manner (advisory
> locking).
> 
> 
>>Windows applications rely on the mandatory locking model of Windows file
>>systems.   If we do not enforce the mandatory locking model, then there
>>is no benefit to doing this work at all.  A cache manager that loses a
>>lock and then continues to allow applications to access the file as if
>>the lock is in place might as well overwrite the file with the output
>>of /dev/random since those will be the resulting semantics.
>>
>>There was an interesting set of discussions on the subject of mandatory
>>vs advisory locking on the nfsv4 wg mailing list.   The conclusion was
>>that mandatory locking must be enforced for Windows applications and
>>Posix implementations which require data integrity.

Eric:

I wanted to come back to this portion of the thread for a few minutes.
Given that the Windows locking model is "mandatory", do you have a
proposal for how "advisory locking" could be used while still
maintaining data integrity?

Jeffrey Altman

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