Messages in this thread | | | Date | Tue, 4 Nov 2008 22:28:11 +0100 | From | Pavel Machek <> | Subject | Re: data corruption: revalidating a (removable) hdd/flash on re-insert |
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On Wed 2008-11-05 00:22:51, Michael Tokarev wrote: > Pavel Machek wrote: >>>>> Every access to removable media is guarded by this revalidation check. >>>>> If you don't see these events, you should not trust this reader, and >>>>> at least never change the media while it is connected. >>>> This is rather nasty data-corrupter. >>> Sure, it is. >>> >>>> Could we at least blacklist >>>> broken device, and force revalidation on each close or something like >>>> that? >>> What's your idea of revalidation if the hardware does not tell you? >>> Get an md5 of the disk content? :) >> >> Well... you should not eject media while fs is mounted or blockdev is >> open, correct? >> >> So can we simply claim 'media changed' on last close/unmount? Sure, >> sometimes media was not changed, but that only hurts performance, not >> correctness... ? > > Well, that's what my tiny proggy, which I used here to work around the > problem, does. It constantly opens/closes the /dev/sdFOO, every 0.5s > currently (I don't think I will be able to replace a media faster than > half a second :), in order to catch REMOVALs of media -- because when > the drive does not see the media anymore, it correctly reports that > the media has changed...
Ok, so we you need to do is to put it into kernel and activate it via blacklist...? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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