Re: file offset corruption on 32-bit machines?

From: Bryan Henderson
Date: Fri Apr 11 2008 - 12:59:59 EST


>So if you write multithreaded code and don't understand what locking
>around shared resources is for, then your application might break.

I think I know what locking around shared resources is for, which is why
I'm surprised the kernel doesn't do it.

Is it normal for a kernel resource not to be thread-safe (i.e. you don't
get advertised/sensible results if two threads access it at the same
time)?

>Can you give an example where locking is being used correctly where this
can
>possibly fail?

I could accept (though I haven't thought about it) that there aren't any
real-world applications that do simultaneous reads and writes through the
same file pointer. I might even accept that there can be no useful
application that does. But can you say such an application is incorrect?

--
Bryan Henderson IBM Almaden Research Center
San Jose CA Filesystems

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