Ext4 troubles

Hi,

A couple of linodes face a weird ext4 issue randomly, as seen in the log below:

blkfront: barrier: empty write xvdc op failed
blkfront: xvdc: barrier or flush: disabled
end_request: I/O error, dev xvdc, sector 46399544
end_request: I/O error, dev xvdc, sector 46399544
Aborting journal on device xvdc-8.

Jun 09 22:11:39 [kernel] EXT4-fs error (device xvdc): ext4_journal_start_sb:327: Detected aborted journal
Jun 09 22:11:39 [kernel] EXT4-fs (xvdc): Remounting filesystem read-only
Jun 10 01:31:57 [kernel] EXT4-fs error (device xvdc): ext4_put_super:818: Couldn't clean up the journal

The servers are running official linode kernel 3.0.18-x86_64-linode38

I tried switching to the 3.2.1 kernel and a custom kernel as well, but no use. It develops the fault a few moments after booting.

And according to this thread: http://forum.linode.com/viewtopic.php?t=8259 and the logs posted above, barriers are already disabled.

How to fix this? Also, it really doesn't make sense for our I/O needs to use ext3, it would be a big performance penalty.