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From: Rainer Weikusat <rweikusat@mssgmbh.com>
Newsgroups: comp.os.linux.development.apps
Subject: Re: mkdir() and thread safety()
Date: Wed, 30 Mar 2011 15:44:40 +0100
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mkaushik <mayank.utexas@gmail.com> writes:
> On Mar 28, 5:59 am, Rainer Weikusat <rweiku...@mssgmbh.com> wrote:
>> David Schwartz <dav...@webmaster.com> writes:
>> > On Mar 25, 5:56 pm, mkaushik <mayank.ute...@gmail.com> wrote:
>> >> I have two threads, each tries to create a directory of the same name
>> >> at the same location using mkdir(). The threads need to be oblivious
>> >> of each others' existence. Do I have to worry about concurrency when I
>> >> use mkdir() to create this directory? Or will mkdir() always return
>> >> success in one thread and EEXIST in the other?

[...]

> Thanks for the answers everyone!

Something which hasn't been mentioned explicitly so far: It is
possible that both calls fail with EEXIST despite one created the
directory: Provided that some kind of network filesystem with a
stateless server is being used (IOW, NFS). It is possible that the
server crashes after it created the directory but before it could send
a reply to the client which requested the action. Once the server is
again available, the retransmitted 'create this directory' requests
from the client should lead to EEXIST.