sd corruption

[effemmeffe]

I recently bought a new sd 8G class 10 and installed on it the last xbian 5.
Today I checked dmesg and saw this:

Code:

[    2.285942] EXT4-fs (mmcblk0p2): warning: mounting fs with errors, running e2fsck is recommended
[    2.290153] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[   11.021491] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)

How do I correct that?
I can't run fsck on mmcblk0p2 because there's / mounted on that.
I tried shutdown -rF now, but still got those message.