Re: [NFS] Re: Non-blocking lock requests during the grace period

[Juan Gomez <juang@us.ibm.com>]

Mike,

I agree with the F_GETLK part, as I pointed out to Trond earlier. However,
I feel it is odd to block a client for about one minutre when it issues
"non-blocking" lock requests. I have seen that Solaris code does so but
still feels odd and it may conflict with what most programmers expect,
though I see your point, perhaps if this was well documented in man pages
there would not be a problem. In Linux this is not the case.


Juan





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|         |           mike.kupfer@sun.c|
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|         |           Sent by:         |
|         |           kupfer@athyra.eng|
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|         |           11/18/02 05:04 PM|
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  |       To:       trond.myklebust@fys.uio.no                                                                              |
  |       cc:       Juan Gomez/Almaden/IBM@IBMUS, linux-kernel@vger.kernel.org, nfs@lists.sourceforge.net                   |
  |       Subject:  Re: [NFS] Re: Non-blocking lock requests during the grace period                                        |
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>>>>> "Trond" == Trond Myklebust <trond.myklebust@fys.uio.no> writes:

>>>>> " " == Juan Gomez <juang@us.ibm.com> writes:

    >> (note that F_GETLK man page does not provide EAGAIN as a
    >> possible error code).

F_GETLK indicates a conflict by changing the arg struct to show the
conflicting lock.

As for the original topic, I would hesitate before changing the client
locking code to return EAGAIN just because the server is in its grace
period.  The "blocking" or "non-blocking" behavior is tied to what
happens when there is already a lock that conflicts with the requested
one.  When the server is in the grace period, it's unknown as to
whether there is already a lock that conflicts with the requested
one.

Mike Kupfer                                            mike.kupfer@sun.com
Solaris File Sharing                                   Speaking for myself,
not for Sun.