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<div class="moz-cite-prefix">Hi Fog,<br>
<br>
RPC callbacks are executed in the epoll thread[1]. Calling
synctask_yield causes that epoll thread to be blocked until, the
corresponding "wake" is called. Most likely, the code calling the
"wake" is tied to a network-event, which wouldn't be 'noticed'
until the epoll thread is unblocked. This is a classic deadlock.<br>
<br>
You could attach gdb to the hung process and check if
synctask_yield was called on the epoll thread. For further
analysis, you might want to paste the output of "thread apply all
bt full" from gdb, attached to the hung process.<br>
<br>
[1] - epoll thread - is a short name for the thread executing
epoll (), 'listening' for network events.<br>
<br>
HTH,<br>
krish<br>
<br>
On 04/26/2013 03:10 PM, fog - wrote:<br>
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<div dir="ltr">Hello everyone,<br>
<div>
<div dir="ltr">
<div>
<div><br>
</div>
I am trying to use syncops in a custom translator to keep
my code at least borderline readable, but I am having
limited success. <br>
<br>
Problem Symptoms: <br>
Using a syncop in a regular fop is fine. However, in a
callback it causes a 'freeze' (synctask_yield called by
the SYNCOP macro doesn't return). <br>
<br>
</div>
<div>What seems to be the Problem: <br>
</div>
<div>Looking at the traces, there is no corresponding trace
from rpc_clnt_reply_init on the client to the trace from
rpcsvc_submit_generic on the server. In other words, the
rpc reply gets sent but isn't correctly received.
Obviously this is not really a networking problem but
something else... I'd guess it's a deadlock somewhere on
the client?<br>
</div>
<div>From the point of the syncop call onwards the client
doesn't 'get' any rpc replies any more (the next GlusterFS
Handshake sent by the client, which is received by the
server and replied to, leads to a disconnection
accordingly).<br>
</div>
<div><br>
</div>
<div>Again: This problem is only occurring when calling a
syncop from a callback function inside my translator, if I
call the same syncop in a fop call it completes fine.<br>
<br>
I hope you can make sense out of the above problem
description. <br>
</div>
<div>Thanks for your time ~<br>
</div>
<br>
</div>
</div>
</div>
<br>
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