Alternate approaches to lock/dead-client problem.
David Collier-Brown
davecb at Canada.Sun.COM
Tue Jan 26 20:00:51 GMT 1999
Nicolas Williams wrote:
> But the question is: is it correct to assume that an SMB session over
> TCP is abandoned when a new connection with the same parameters is
> opened to the server?
It is in a sort of insane sense: the CIFS spec claims
so, but no-one will admit to actually doing such a
dumb thing (:-))
Any multi-user client can make connections to a server
on behalf of different users. Right now I have a connection
and another process on my box has a connection. I'd be
seriously annoyed if the server dropped me when the
script started.
The sufficient condition is
user x from client y has locked file z &&
client z has crashed and resumed &&
user x from client y wants file z
I was working to order this so the minimum number
of checks occur in a known time-critical path.
By mostly gut feel I proposed this ordering:
whenever user x from client y wants file z 1
&& file z is locked 2
&& user x from client y has locked file z 3
&& client z has crashed 4
in the hopes that the check of line 3 could be decomposed
into
&& lock is from the same host 3a
&& user x has locked file z 3b
so I could bail out of the checking at step 3b,
before getting into expensive operations in step 4.
--dave
--
David Collier-Brown, | Always do right. This will gratify some people
185 Ellerslie Ave., | and astonish the rest. -- Mark Twain
Willowdale, Ontario | http://java.science.yorku.ca/~davecb
Work: (905) 477-0437 Home: (416) 223-8968 Email: davecb at canada.sun.com
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