Re: ftruncate-mmap: pages are lost after writing to mmaped file.

From: Linus Torvalds
Date: Thu Mar 19 2009 - 12:58:53 EST




On Fri, 20 Mar 2009, Nick Piggin wrote:
>
> Yeah, probably no need to hold private_lock while tagging the radix
> tree (which is what my version did). So maybe this one is a little
> better. I did test mine, it worked, but it didn't solve the problem.

Ahh, so you re-created it? On ext2 only, or is it visible on ext3 as well?
I've not even tested - I assumed that I would have to boot into less
memory and downgrade my filesystem to ext2, which made me hope somebody
else would pick it up first ;)

> Still, it does appear to solve a real race, which we should close.

A very small and unlikely race, but yeah - the patch isn't large, removes
more lines than it adds, and the code seems to make _more_ sense with it
in place than without.

Linus
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