The object will be hashed to a placement seed (ps) based on the pg_pool's
hash function. This allows new hashes to be introduced into an existing
object store, or selection of a hash appropriate to the objects that
will be stored in a particular pool.
Signed-off-by: Sage Weil <sage@newdream.net>
We were using the (weak) dcache hash function, but it was leaving lower
bits consecutive for consecutive (inode) objects. We really want to make
the object to pg mapping random and uniform, so use a proper hash function
here.
This is Robert Jenkin's public domain hash function (with some minor
cleanup):
http://burtleburtle.net/bob/hash/evahash.html
This is a protocol revision.
Signed-off-by: Sage Weil <sage@newdream.net>
Mix the preferred osd (if any) into the placement seed that is fed into
the CRUSH object placement calculation. This prevents all the placement
pgs from peering with the same osds.
Rev the osd client protocol with this change.
Signed-off-by: Sage Weil <sage@newdream.net>
These headers describe the types used to exchange messages between the
Ceph client and various servers. All types are little-endian and
packed. These headers are shared between the kernel and userspace, so
all types are in terms of e.g. __u32.
Additionally, we define a few magic values to identify the current
version of the protocol(s) in use, so that discrepancies to be
detected on mount.
Signed-off-by: Sage Weil <sage@newdream.net>
