On Sun, Jun 02, 2013 at 10:16:30PM -0400, George Spelvin wrote: > > Fortunately metadata checksumming is still "experimental" and not in a shipping > > e2fsprogs, so there should be few users affected by this. > > Am I reading this patch correctly that this changes which half of > the 32-bit checksum is stored on little-endian (e.g. x86) machines? > Before, it stored the low 16 bits of cpu_to_be32(csum), meaning the > high 16 bits of csum. ...unless you're using a BE system in which case it's the low 16 bits. :) > Now, it's cpu_to_be16(csum32), which is the low 16 bits of csum32. > > It so happens that I have multiple metadata_csum file systems. > (I enabled it a while ago on a machine where I wasn't sure if corruption > was RAM or disk, and have been using it on SSE4.2 machines since.) > > Is there an upgrade path? Also, what's the corresponding e2fsprogs > commit that supports this change? The kernel patch fixes journal bogosity when moving a disk between big and little endian systems. e2fsprogs didn't have the brokenness, so there's no change needed. In theory you'd only hit this if you happened to crash an x86 box with an ext4 fs, move the disk to a ppc, and try to recover it there. The upgrade path is to umount cleanly and reboot with a patched kernel while hoping that you don't crash while rebooting. Sorry about the bumpy metadata_csum ride. --D -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
