spinning use of fsck

Ran into this a few minutes ago:

Starting file system checks:
/dev/aacd0s1a: FILE SYSTEM CLEAN; SKIPPING CHECKS
/dev/aacd0s1a: clean, 224350 free (670 frags, 27960 blocks, 0.3%
fragmentation)
/dev/aacd0s1d: DEFER FOR BACKGROUND CHECKING
/dev/aacd0s1e: PARTIALLY TRUNCATED INODE I=3181750
/dev/aacd0s1e: UNEXPECTED SOFT UPDATE INCONSISTENCY; RUN fsck MANUALLY.
THE FOLLOWING FILE SYSTEM HAD AN UNEXPECTED INCONSISTENCY:
        ufs: /dev/aacd0s1e (/usr)
Automatic file system check failed; help!
Aug 21 15:27:54 init: /bin/sh on /etc/rc terminated abnormally, going to
single
user mode
Aug 21 15:27:54 init: can't get /dev/console for controlling terminal:
Operation
 not permitted
WARNING: R/W mount of /usr denied.  Filesystem is not clean - run fsck
WARNING: /var was not properly dismounted
WARNING: R/W mount of /usr denied.  Filesystem is not clean - run fsck
WARNING: /var was not properly dismounted
WARNING: R/W mount of /usr denied.  Filesystem is not clean - run fsck
WARNING: /var was not properly dismounted
WARNING: R/W mount of /usr denied.  Filesystem is not clean - run fsck
WARNING: /var was not properly dismounted
WARNING: R/W mount of /usr denied.  Filesystem is not clean - run fsck
WARNING: /var was not properly dismounted
WARNING: R/W mount of /usr denied.  Filesystem is not clean - run fsck
WARNING: /var was not properly dismounted
<repeat until forever>

Unclear to me exactly what the failure mode is here, perhaps a problem
with /dev/console...

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert_at_fledge.watson.org      Principal Research Scientist, McAfee Research