file checking saved me every time, it is just a problem of bad superblock, datas are not corrupted.
I dont have a signal from the power supply before shuting down the power.
Most of the data are on sdb, an external SD card, and I dont have this kind of problem with this card (I have added some option in the fstab file to avoid this)
My question is how to pass this kind of option to the kernel, via uboot, when mounting sda2 ?