Unlock stream (cms-externals versionj)

[bbockelm]

OnReadTimeout will call OnError with the Stream's lock held.
This causes OnError to invoke the user's callback with the
Stream lock held, possibly causing a lock ordering issue.

This fixes an observed deadlock within CMSSW over the following
objects:

Thread 1
FileStateHandler::VectorRead takes FileStateHandler lock
Stream::Send tries to take Stream lock

Thread 5
FileTimer::Run takes FileTimer lock
FileStateHandler::Tick tries to take FileStateHandler

Thread 6
Stream::OnReadTimeout takes Stream lock
DelayedClose::HandleResponseWithHosts (this is callback code in CMSSW); this deletes a File object, which eventually calls
FileTimer::UnRegisterFileObject tries to take FileTimer lock

See discussion in https://hypernews.cern.ch/HyperNews/CMS/get/recoDevelopment/1362/1/1/1/1/1/1/1/1/1/1/1/1/1/2.html

[bbockelm]

@smuzaffar @davidlange6

This is the PR we discussed in today's Core meeting.

[davidlange6]

@Degano - lets try to integrate this in 76x and then 75x (and then 74x after we digest)

[ghost]

Done, since tonight IBs didn't start already this should go in.

On Tue, Jul 7, 2015 at 10:28 PM, David Lange notifications@github.com
wrote:

@Degano https://github.com/degano - lets try to integrate this in 76x
and then 75x (and then 74x after we digest)

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