Despite the ext4 filesystem losing it’s ‘dev’ tag and being labelled as stable in Linux 2.6.28, there are problems.
One of the ways the ext4 filesystem improves upon ext3 is delayed allocation. When a new file is created, rather than immediately write the change, the change is noted in the journal, and the data is written to the disk within the next 45-150 seconds.The problem happens after a system crash. If your machine crashes, any unwritten file can be lost. This is especially hazardous if the file being written is a system file/setting or part of grub.
I had that exact problem last night. My computer crashed, and after rebooting, it got stuck at GRUB with error 17.
I booted a recoveryCD and in the terminal typed
fsck.ext4 -y /dev/sda2
fsck is a Filesystem Check
‘-y’ will answer yes to fix all errors
/dev/sda2 is my first hard drive, second partition, where my /boot partition is located
Hope this helps anyone else with a corrupted partition