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Date: Fri, 05 Sep 2003 00:37:03 -0700
From: Terry Lambert <tlambert2@mindspring.com>
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To: Paul Richards <paul@inty.com>
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Subject: Re: Text file busy
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Paul Richards wrote:
> Overwriting a file that's currently executing results in a "Text file
> busy" error.
> 
> When did this start happening?
> 
> This was something that was fixed way back on FreeBSD but it seems to be
> a problem again.

You are opening an existing file for write.  You need to rename
on top of it, or delete and create a new one, and this will not
happen.

The issue is that the pages in the executing file are not
necessarily all in core, so it can't copy-on-write them, since
it doesn't know that they are being dirtied.

The copy-on-write behaviour is relatively new; old System V
and Xenix system did not permit even deleting an executing
file, since the process did not hold an open file reference
on the file.

-- Terry