Make the integer hash function a property of the bucket it is used on. This
allows us to gracefully add support for new hash functions without starting
from scatch.
Signed-off-by: Sage Weil <sage@newdream.net>
Even when we encounter a corrupt bucket. We still BUG(). This fixes
the warning
fs/ceph/crush/mapper.c: In function 'crush_choose':
fs/ceph/crush/mapper.c:352: warning: control may reach end of non-void function
'crush_bucket_choose' being inlined
Signed-off-by: Sage Weil <sage@newdream.net>
CRUSH is a pseudorandom data distribution function designed to map
inputs onto a dynamic hierarchy of devices, while minimizing the
extent to which inputs are remapped when the devices are added or
removed. It includes some features that are specifically useful for
storage, most notably the ability to map each input onto a set of N
devices that are separated across administrator-defined failure
domains. CRUSH is used to distribute data across the cluster of Ceph
storage nodes.
More information about CRUSH can be found in this paper:
http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf
Signed-off-by: Sage Weil <sage@newdream.net>
