hammer_alloc_data panic

[Matthew Dillon]

: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?
:
:Why wouldn't the reblocker anyways start with the almost empty blocks? 
:Which order is it picking right now?
:
:cheers
:   simon

    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.  Ok, I admit I really don't want to support
    small filesystems anyway, personally I think ~50G is the minimum
    reasonable size for a HAMMER filesystem.  But I know in my heart that
    people are going to want to use HAMMER on smaller filesystems so I am
    pushing to make it work as well as possible.

    I am open to the many proposed solutions and after the release if someone
    wants to take on that task, freeing me up for other continuing work,
    it would be even better!

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>