John wrote:
> Alessandro Vesely wrote:
>> Rocco Scappatura wrote:
>>   
>>>>> in pop3 log file I get theese errors:
>>>>>
>>>>> ERR: rename(./new/1179507568.V804I4c4004.mail4
>>>>>         
>>>> That is the only message that looks somewhat strange. It 
>>>> probably happened while moving files from "./new" to "./cur". 
>>>> The message itself is truncated, as the target name and error 
>>>> reason are missing. Does it happen often?
>>>
>>> About 50 per day vs 200000 mail per day downloaded..
>>
>> Hmm... I'm not sure if that can happen because a user logs
>> in twice and performs the same operation concurrently. An
>> error like "no such file or directory" may point in that
>> direction. It seems the pop3 daemon does not lock maildirs.
>
> http://www.lerfjhax.com/articles/2007/05/21/ocfs2-racy-rename
> renames aren't pure atomic in some environments, according to this. They 
> introduced a semaphore I guess, and it can result in a race condition in 
> certain circumstance.

The atomicity of rename is not much useful in this case anyway,
because the application doesn't know the filename beforehand and
thus it has to first read it and then rename it. The gap between
the two operations is stressed by doing each operation a bufferful
of files at a time (which is necessary since mixing readdir and
rename has undefined behavior.)




































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