[CentOS] EXT3 fs error on RAID1 device

Hi all.

I have a Dell SC440 running Centos 4.4. It has two 500GB disks in a
RAID1 array using linux software raid (md1 is / and md0 is /boot).
Recently the root file system was remounted read-only for some reason.
The logs don't show anything unusual, presumably the file system was
read-only before anythng was logged. Running dmesg showed this error
repeated many times:

EXT3-fs error (device md1) in start_transaction: Journal has aborted

Before rebooting the system I checked the raid array status with cat
/proc/mdstat and mdadm. No errors were shown. When rebooting the
system I let fsck do a check of the file systems. It reported several
errors and I let it fix them. The thing that's bothering me is I can't
find any reason for the EXT3 error. Nothing seems to be wrong with the
array or the hardware.

I also noticed a few worrying messages while booting up and shutting
down. On boot-up mdamd complains that super-minor should only be
declared once and then there's a message that File descriptor 21 is
open. On shutdown there are messages that md0 and md1 are in immediate
safe mode and that md1 is till in use.

Is my system totally hosed or can I ignore these warnings?

Thanks,
Rasmus