tree ee93c0de758571721f594c35f556ca79468e684f
parent 6c0f3af72cb1622a66962a1180c36ef8c41be8e2
author Sage Weil <sage@newdream.net> 1292377072 -0800
committer Sage Weil <sage@newdream.net> 1294874113 -0800

ceph: implement DIRLAYOUTHASH feature to get dir layout from MDS

This implements the DIRLAYOUTHASH protocol feature, which passes the dir
layout over the wire from the MDS.  This gives the client knowledge
of the correct hash function to use for mapping dentries among dir
fragments.

Note that if this feature is _not_ present on the client but is on the
MDS, the client may misdirect requests.  This will result in a forward
and degrade performance.  It may also result in inaccurate NFS filehandle
generation, which will prevent fh resolution when the inode is not present
in the client cache and the parent directories have been fragmented.

Signed-off-by: Sage Weil <sage@newdream.net>