Re: partially encrypted filesystem
From: H. Peter Anvin
Date: Wed Dec 03 2003 - 23:01:35 EST
Followup to: <3FCE8CF5.4030006@xxxxxxxxx>
By author: Jeff Garzik <jgarzik@xxxxxxxxx>
In newsgroup: linux.dev.kernel
> Linus Torvalds wrote:
> > With an encrypted filesystem, you can't do that. Or rather: you can do it
> > if the filesystem is read-only, but you definitely CANNOT do it on
> > writing. For writing you have to marshall the output buffer somewhere
> > else (and quite frankly, it tends to become a lot easier if you can do
> > that for reading too).
> > And that in turn causes problems. You get all kinds of interesting
> > deadlock schenarios when write-out requires more memory in order to
> > succeed. So you need to get careful. Reading ends up being the much easier
> > case (doesn't have the same deadlock issues _and_ you could do it in-place
> > anyway).
> FWIW zisofs and ntfs have to do this too, since X on-disk compressed
> pages must be expanded to X+Y in-memory pages...
zisofs is read-only, so it doesn't apply.
<hpa@xxxxxxxxxxxxx> at work, <hpa@xxxxxxxxx> in private!
If you send me mail in HTML format I will assume it's spam.
"Unix gives you enough rope to shoot yourself in the foot."
Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/