I've a Rpi 3 Model B V1.2 with an Intenso 16GB Micro SD HC (up to 90 MB/s) running a RASPBIAN JESSIE LITE (Rel. Date: 2016-05-27), power is supplied via USB by a Linux machine.
The system worked correctly for about a week, but since yesterday the webserver and ssh were not working anymore, although the previously installed VPN was/is still connecting to the VPN Server.
Apparently the power of RPI was taken off without it first shutting down correctly (not 100% sure about this).
Today I connected a monitor and find out that the boot is stucked on EXT4-fs error (see attached image), I tried to login but this is not possible, everytime I type something a new line with error appears.
How can I fix this error? If no fix possible, how can I recover certain files? (I've no backup of a small app I did)