[U-Boot-Users] [PATCH] Use `ln -sf` rather than `rm -f && ln -s`

[Mike Frysinger]

On Monday 28 January 2008, Wolfgang Denk wrote:
> In message <200801280638.59012.vapier at gentoo.org> you wrote:
> > odd ... git-send-email ate the explanatory text ...
> > ---
> > The -f option to `ln` should give the same behavior as the -f option to
> > the `rm` command.  It is better to do this in one shot so as to avoid
> > race conditions when building in parallel.  I build on a quad G5 and
> > without this change, it isn't uncommon for the build to fail when using
> > -j8 due to this small window where the files don't actually exist.
>
> Note that "ln -s -f" will come down to two separate system calls as
> well:
>
> 	...
> 	unlink();
> 	symlink();
> 	...
>
> So you don't avoid the race condition; you're just making it a little
> less likely at the cost of reduced portability.

yes, i know it's much less likely, but that difference on my system has been 
from 1-in-20 build failures to 1-in-none-so-far-out-of-hundreds.  the real 
fix is to overhaul the u-boot build system, but that'll take quite a bit of 
time and this change is for all practical purposes, Good Enough.  i dont know 
what portability issues you refer to considering the -f flag is in POSIX and 
has been supported on all Linux systems since before that (pre-2000).
-mike
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