Messages in this thread | | | Date | Thu, 4 Dec 2003 15:17:25 +0100 | From | Jörn Engel <> | Subject | Re: partially encrypted filesystem |
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On Wed, 3 December 2003 16:08:17 -0800, Linus Torvalds wrote: > On Wed, 3 Dec 2003, Jörn Engel wrote: > > > > Haven't heard about anything working yet, but it shouldn't be too hard > > to change something existing. For jffs2, I would guesstimate one or > > two month to add the necessary bits, but jffs2 is not first choice as > > a hard drive filesystem. Not sure about other filesystems. > > Encryption is not that easy to just tack on to most existing filesystems > for one simple reason: for performance (and memory footprint) reasons, > most of the filesystems out there are doing "IO in place". In other words, > they do IO directly into and directly from the page cache. > > 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).
Isn't that a problem already handled by all compressing filesystems? Or did I miss something really stupid?
Jörn
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