Re: enbd 2.4.32/kernel 2.6.12.3 pid file problem

u.schmeling wrote:
> Peter T. Breuer wrote:
>> "Also sprach u.schmeling:"
>>  
>>> Maybe this problem is not really related to the above combination.
>>> When starting a client I get:
>>> nbd/pidfile  8854: <# 140> lockpidfile returning err -16 for lock 
>>> attempt
>>> enbd-client  8854: <#4257> main There is already a enbd-client running.
>>>    
>>
>>
>> Did you notice WHICH pid was in the pidfile?
>>
>> I can only find one call that will look in the pidfile in the client 
>> code, and it is in nbd/enbd-client.c:
>>
>>    // PTB (re) make our (session master) pidfile with our pid inside 
>>    // after fork
>>    if (client->cid) {
>>        struct nbd_pidfile * pidfile = &client->pidfile;
>>        void removepidfile () {
>>            pidfile->unlock (pidfile);
>>        };
>>
>>        err = pidfile->lock (pidfile);
>>        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>        if (err < 0) {
>>            // PTB this probably better not be deadly, so fakeroot can 
>>            // launch
>>
>>
>> This is right in main(). The main code forks and dies as part of the 
>> go-daemon procedure, and its child does the pidfile check.  So it can't
>> be a race with ITSELF.
>>
>> The check code itself only will complain if the pid already in the 
>> pidfile
>> is actually running at the time.
>>
>> I would GUESS that you are running this code autmatically at boot
>> and that sometimes at reboot the old pid in the pidfile is a valid pid
>> for a new running process.
>>
>> Is that it?
>>
>> Peter
>>
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>>  
> No that isn't the way it happens. Before starting I have removed all 
> pid files and the problem occurs too. So I have added a printout of 
> the related pid, when the problem occurs. Will try to add additional 
> printouts, so that you can see what happens during this day.
> regards Uwe
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Have logged the results, here they are:
enbd-client 25471: client says target 0 is mks:1030
enbd-client 25471: client (-1) opened device /dev/nda
enbd-client 25471: client (-1) manager opened NBD device /dev/nda (2b00)
enbd-client 25471: client (-1) set kernel bdflush sync boundary to 80% 
from 0%
enbd-client 25471: client (-1) left kernel bdflush async boundary at 0%
enbd-client 25471: client (-1) manager detaches from shell
nbd/pidfile 25474: <# 130> myckpidfile Conflicting pid parent: 25471 
mypid: 25474 file: 25408
nbd/pidfile 25474: <# 141> lockpidfile returning err -16 for lock attempt
enbd-client 25474: <#4257> main There is already a enbd-client running. 
Check in /var/run/enbd-client-0.pid!

Have first removed the latest pids, no other clients are running. Then 
"enbd start client 0" with the above result. Wonder where this 25408 pid 
comes from.
Uwe