I accidentially created a write-back EnhanceIO cache for my root partition. I didn't know that
Creating a writeback cache on root device is not supported. This is because the root device is mounted as read only prior to the processing of udev rules.
as stated on the Persistence.txt of EnhanceIO.
I create a LRU write-back cache for the device which contains my btrfs root filesystem with eio_cli, used it and rebooted. The filesystem is no longer mountable due to the isses described in the citation above. I manipulated the initramfs image in a live system and inserted the kernel modules enhanceio.ko, enhanceio_lru.ko and enhanceio_fifo.ko. I don't seem to find a way to attempt a resuce.
I'm uncertain whether the device can be restored externally by creating the same cache in another system and cleaning the cache there.
I'm using Linux 3.19.3 on Ubuntu 15.04-beta2.
