[jcifs] Issues with connections to servers that reboot

[Sean Daley]

I seem to be running into a random issue with JCIFS re-connecting to a
server that is
rebooted.  I've attached a simple Java program which connects to the
Admin$ share
and calls listFiles on it.  It then repeats this every second.

Sometimes, when I reboot a server and/or shut it down for a few
minutes and re-start
it, the JCIFS connection to that server never seems to recover.  This
doesn't seem to
happen to all of my servers but it does happen to some of them.

I'm currently using Fedora 14 x86_64 as the JCIFS client connecting to
a wide-variety
of windows boxes.  The biggest windows culprit I have seems to be a
Windows 2008r2
box.

For this particular box, I get the following logs from this test class:
0: fileList returned 80 and took 190(ms).
1: fileList returned 80 and took 11(ms).
...
33: fileList returned 80 and took 5(ms).
34: fileList failed: Transport1[testhost/10.20.14.15:445] timedout
waiting for response to
Trans2FindFirst2[command=SMB_COM_TRANSACTION2,received=false,errorCode=0,flags=0x0018,flags2=0xC803,signSeq=0,tid=2048,pid=63708,uid=2048,mid=73,wordCount=15,byteCount=19,totalParameterCount=18,totalDataCount=0,maxParameterCount=10,maxDataCount=65535,maxSetupCount=0,flags=0x00,timeout=0,parameterCount=18,parameterOffset=66,parameterDisplacement=0,dataCount=0,dataOffset=84,dataDisplacement=0,setupCount=1,pad=1,pad1=0,searchAttributes=0x16,searchCount=200,flags=0x00,informationLevel=0x104,searchStorageType=0,filename=\]
took 30001(ms).
35: ... (repeats the exact same thing as 34: every 30 seconds).

I've let it run for awhile now and it will just continuously report
the "timedout waiting for ..."
error every 30 seconds.

If I stop and re-start the program though it will re-connect just
fine.  If I enable
jcifs.Config.setProperty("jcifs.smb.client.ssnLimit", "1");
the problem also does not occur but I'd really rather not do that as
I'm going to potentially
be working with the same set of hosts many times and I rather like the
caching that's
being done here.

I've played around with this program and differing target servers as
well as changing things
around to do something else other than a listFiles check (like an
exists) check and I've
received differing behaviors along the way.  For some of my
environment, with the
exists check, I got similar timeout behavior but it was a more
straight-forward exception
of "connection timed out".  What was worse though was that each time I
got that, I
was left with a new Thread running with the following stack trace:

#########
Daemon Thread [Transport1] (Suspended)	
	PlainSocketImpl.socketConnect(InetAddress, int, int) line: not
available [native method]
	SocksSocketImpl(PlainSocketImpl).doConnect(InetAddress, int, int) line: 333	
	SocksSocketImpl(PlainSocketImpl).connectToAddress(InetAddress, int,
int) line: 195
	SocksSocketImpl(PlainSocketImpl).connect(SocketAddress, int) line: 182	
	SocksSocketImpl.connect(SocketAddress, int) line: 366	
	Socket.connect(SocketAddress, int) line: 529	
	Socket.connect(SocketAddress) line: 478	
	Socket.<init>(SocketAddress, SocketAddress, boolean) line: 375	
	Socket.<init>(String, int) line: 189	
	SmbTransport.ssn139() line: 185	
	SmbTransport.negotiate(int, ServerMessageBlock) line: 240	
	SmbTransport.doConnect() line: 302	
	SmbTransport(Transport).run() line: 232	
	Thread.run() line: 662	
#########

So every 30 seconds, I'd get the connection timedout error, then we'd
try to connect
again and a new Daemon Thread Transport1 would start.  These threads would take
upwards of 4 - 5 minutes (at least) before they finally terminated.
During that time though
we'll keep on accumulating more and more of them as we try to
re-connect.  Once again, if I
stop and re-start the test program it works just fine again right away.

Is there any way to force a new SmbTransport to get created without
setting ssnLimit to 1?
I briefly tried setting it to 1 but I have some concerns about doing
that because we lose
the benefit of caching, plus, unless I'm misreading the code, it looks like the
CONNECTIONS LinkedList can grow unbounded.  So with ssnLimit == 1, we're just
constantly creating new SmbTransports and adding them to CONNECTIONS.  I didn't
find any place where we were removing them from the list though.

Any thoughts on this?  Or is there any additional information I can get you?
Any help would be greatly appreciated.

Sean
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