cperciva bbad79fbcc Stop trying to zero UFS1 superblocks if we fall off the end of the disk.
This avoids a potentially many-hours-long loop of failed writes if newfs
finds a partially-overwritten superblock (or, for that matter, random
garbage which happens to have superblock magic bytes); on one occasion I
found newfs trying to zero 800 million superblocks on a 50 MB disk.

Reviewed by:	mckusick
MFC after:	1 week
2011-04-26 02:06:31 +00:00
..
2011-02-22 15:31:40 +00:00