hammer_alloc_data panic

[Simon 'corecode' Schubert]

Matthew Dillon wrote:
:We absolutely need this.  People will complain left and right if it 
:isn't "just" working.
:
:Probably I'm missing something, but can't we reserve N blocks for 
:reblocking purposes, so that the reblocker always can make progress?
    Yes, but if the filesystem has 60% fragmentation we are talking close
    to a gigabyte needing to be reserved (from my testing with Gergo's
    wonderfully fragmented 14G filesystem).  That clearly will not work very
    well for small filesystems.
Why do you need to reserve 1GB?  Wouldn't (in theory), one block be 
enough to be able to make progress?

cheers
  simon