[btrfs-devel][patch]Cache blocks in the hole at beginning of a block group

[Chris Mason]

On Tue, 11 Sep 2007 23:26:40 +0800
"Yan Zheng" <yanzheng at 21cn.com> wrote:

> Hi
> 
> When first extent item in a block group isn't at beginning of that
> block group,  blocks in the hole (at beginning of a block group) is
> free.

Thanks, you've definitely found a bug in the current code, but I'm
afraid we can't assume the start of the block group is free.  There
could be an extent allocated in the last block group that extends into
the current one.

So, we need to find the previous extent and make sure it doesn't
overlap.

-chris