Intermittent problems mounting /home

This is Ubuntu 12.04LTS running the latest Linode kernel.

My /etc/fstab is as follows:

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system=""><mount point=""><type><options><dump><pass>proc        /proc        proc    defaults                       0 0
/dev/xvda   /            ext3    noatime,errors=remount-ro      0 1
/dev/xvdb   none         swap    sw                             0 0
/dev/xvdc   /home        ext3    defaults                       0 2</pass></dump></options></type></mount></file> 

The problem is that intermittently the mount of /dev/xvdc on /home fails. Here's the startup script output when that happens:

fsck from util-linux 2.20.1
/dev/xvda: clean, 65383/5690496 files, 1438641/5701632 blocks
mountall: Disconnected from Plymouth
fsck from util-linux 2.20.1
fsck.ext3: Device or resource busy while trying to open /dev/xvdc
Filesystem mounted or opened exclusively by another program?
mountall: fsck /home [2041] terminated with status 8
mountall: Unrecoverable fsck error: /home
mountall: Skipping mounting /home since Plymouth is not available

Any ideas what could be going on?