An f2fs teardown

I'm not sure if you were joking here, but since you put no smiley in your message, let me warn you about two reasons why you really should not consider this:

* The file system is not stable or merged yet, and will very likely see incompatible changes to the on-disk layout. Even if you don't run into bugs that cause your data to get destroyed, you won't be able to read the data anymore with the version of the file system that eventually gets merged.

* A lot of SD cards are not sufficient in their hardware characteristics to support f2fs. Have a look at https://wiki.linaro.org/WorkingGroups/Kernel/Projects/Fla..., all SD cards with a number of less than 7 in the "# open AUs linear" column or cards that don't have a power-of-two erase block size.will not work correctly with f2fs. It's not worse than using ext4 or btrfs on the same devices though, but you should not do that either, at least not if you are storing important data.