On Fri, 18 Mar 2022 at 10:11, Christoph Hellwig <hch@xxxxxx> wrote: > > On Thu, Mar 17, 2022 at 10:44:01AM +0100, Ulf Hansson wrote: > > Stating that it can't work is probably not a correct statement. > > Certainly it can, but it depends on how "secure" (or clever) the > > implementation of the FTL is in the flash media. I mean, nothing > > prevents the FTL from doing a real erase on erase block level and > > simply let the "secure erase" request wait on that operation to be > > completed. > > Well, that assumes it can find all the previous copied of the data. > Having worked with various higher end SSDs FTLs I know they can't, > so if an eMMC device could that would very much surpise me given > the overhead. An eMMC is no different from an SSD in this regard, so you are most definitely correct. BTW, I was one of those guys working with FTLs myself, but it was a long time ago, when NAND/NOR flashes were less complicated to manage. Anyway, to really make things work, one would need some additional low level partitioning - or commands to tag the data for special purposes. eMMCs do have some support for things like this, but whether it actually works to serve this particular use case (secure erase), I really can't tell. Kind regards Uffe
