Re: fcntl(F GETLEASE) semantics??

["Michael Kerrisk" <mtk-lkml@gmx.net>]

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Trond,

> to den 11.08.2005 Klokka 15:22 (+0200) skreiv Michael Kerrisk:
> 
> > As noted already, I don't know much of CIFS and SAMBA.
> > But are you saying that it is sensible and consistent that
> > "a process can open a file read-write, and can't place a 
> > read lease, but can place a write lease"?  
> 
> It is just as "sensible and consistent" as being able to open the file
> read-write and being able to place a read lease but not a write lease.
> What is your point?

I think my metapoint really is this: there has never been a 
clearly documented statement of how File Leases are supposed 
to behave on Linux.  There is just some code... how is one 
supposed to know what it _should_ do?  (The manual page text 
was my attempt to discover the details, after the fact.)

Can you provide an explanation of how file leases should 
behave?  That is, a tabulation of the expected behavious 
for the possible cimbinations of

[lease type] X 
[open() access-mode employed file placing lease] X
[open() access-mode employed by other process(es)]

?

> Make no mistake: this is not a locking protocol. It is implementing
> support for a _caching_ protocol.

Yes, that I knew.

Cheers,

Michael

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