>>>>> "Paul" == Paul Millar <paul.millar@xxxxxxx> writes: Paul> Please correct me if I'm wrong here, but T10 DIF/DIX refers only Paul> to data integrity protection from the OS's FS-level down to the Paul> block device: a userland application doesn't know that it is Paul> writing into a FS that is utilising DIX with a DIF-enabled storage Paul> system. My point was that it is possible to have different protection types in play (and thus different checksums) as long as you overlap the protection envelopes. At the expense of having to calculate checksums multiple times, of course. Paul> Unfortunately, any such solution would be btrfs-specific, since (I Paul> believe) no one has standardised how to extend T10 into userspace. Not yet, but we're working on a generic interface that would allow the protection information to be attached. This is not going to be tied to just T10 DIF. The current Linux block layer integrity handles different types of protection information. Paul> I believe NFS currently doesn't support checksums (as per v4.1). Paul> Looking into more detail, Alok Aggarwal gave a talk at 2006 Paul> connectathon about this. Alok's slides have a nice diagram (slide Paul> 11) showing the kind of end-to-end integrity I'm after. The issue Paul> is how to achieve the assurance between "NFS Server" and "Local Paul> FS" on the right. Paul> For NFS, I believe there aren't any plans for introducing checksum Paul> support for v4.2. Perhaps it'll appear with the later minor Paul> versions of the standard. I haven't looked into this for a long time. Last time I talked to the NFS folks they seemed to think it would be possible to bridge the two methods. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
