ceph: use strong hash function for mapping objects to pgs
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>
diff --git a/fs/ceph/ceph_fs.h b/fs/ceph/ceph_fs.h
index ae52382..25fc537 100644
--- a/fs/ceph/ceph_fs.h
+++ b/fs/ceph/ceph_fs.h
@@ -38,7 +38,7 @@
#define CEPH_OSD_PROTOCOL 7 /* cluster internal */
#define CEPH_MDS_PROTOCOL 9 /* cluster internal */
#define CEPH_MON_PROTOCOL 5 /* cluster internal */
-#define CEPH_OSDC_PROTOCOL 21 /* server/client */
+#define CEPH_OSDC_PROTOCOL 22 /* server/client */
#define CEPH_MDSC_PROTOCOL 29 /* server/client */
#define CEPH_MONC_PROTOCOL 15 /* server/client */