Ran into this one using mongodb-linux-x86_64-2010-07-08. Since mongo tends to be file hungry, I was going to do a ulimit -n 300000. However, I dropped the '-n' by accident (i.e. ulimit 300000), which defaults to a -f (file size (blocks, -f) 300000).

Started up mongod and ran a mongorestore. Last thing in the mongod log is:

Thu Jul 8 20:42:08 done allocating datafile /mnt/data/lindex.2, size: 256MB, took 2.1 secs
Thu Jul 8 20:42:55 allocating new datafile /mnt/data/lindex.3, filling with zeroes...

when the mongod process just exits with "File size limit exceeded." in stderr. I can understand the process not being able to write new data, but just exiting was unexpected.