On Fri, Nov 19, 2010 at 10:50:03AM -0500, Christoph Hellwig wrote: > > It's a huge issue for virtualization, where naive TRIM implementations > can expose data deleted in one VM to others. It's also a huge issues > for RAIDs as mentioned by you. Fair enough, I'll buy that. If you are sharing an SSD using virtualization across two VM's with different trust bounaries, non-deterministic TRIM could very well be an issue, depending on how it the "non-deterministic" bit was implemented. (I can think of one PCIe-attached flash implementation I know of where the trim is simply not persistent across a power failure, such that if Alice trims a block, it will return 0, but if no one rewrites the block before a power failure, then reading that some block will return Alice's original data, and not data belonging to Bob. This would be an example of a non-deterministic TRIM that would be problematic for RAID, but not from a security perspective. OTOH, the trim command is blazingly fast on this implementation, since there is absolutely no flash write or erase operation associated with the TRIM, and so mount -o discard makes a lot of sense for this particular storage device.) - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
