Re: race condition on looking up inodes

From: Alexander Viro (viro@math.psu.edu)
Date: Sun Apr 08 2001 - 23:39:37 EST


On Mon, 9 Apr 2001, warren wrote:

>
>
> Hi,
> I had post a simillar message before.
> Thanks for the replay from Albert D. Cahalan. But i found some results
> confusing me.
> For example, process 1 and process 2 run concurrently and execute the
> following system calls.
>
> rename("/usr/hybrid/cfg/data","/usr/mytemp/data1"); /*for process 1*/
>
> ----------------------------------------------------------------
>
> rename("/usr/mytemp/data1","/usr/test");/* for process 2*/

> ----------------------------------------------------------------
> It is possible that context switch happens when process 1 is look ing up
> the inode for "/usr/mytemp/data1" or the inode for "/usr/hybrid/cfg/data".

> It will result in diffrent behaviour for process 2 and confuses the
> application.

> If so,how does Linux solve?

Solves what, precisely? Result depends on the order of these calls. If
you don't provide any serialization - you get timing-dependent results
you were asking for. What's the problem and what behaviour do you expect?

Besides, what's the difference caused by the moment of context switch?

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This archive was generated by hypermail 2b29 : Sun Apr 15 2001 - 21:00:10 EST