Merge branch 'nfs-for-2.6.39' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6

* 'nfs-for-2.6.39' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (54 commits)
  RPC: killing RPC tasks races fixed
  xprt: remove redundant check
  SUNRPC: Convert struct rpc_xprt to use atomic_t counters
  SUNRPC: Ensure we always run the tk_callback before tk_action
  sunrpc: fix printk format warning
  xprt: remove redundant null check
  nfs: BKL is no longer needed, so remove the include
  NFS: Fix a warning in fs/nfs/idmap.c
  Cleanup: Factor out some cut-and-paste code.
  cleanup: save 60 lines/100 bytes by combining two mostly duplicate functions.
  NFS: account direct-io into task io accounting
  gss:krb5 only include enctype numbers in gm_upcall_enctypes
  RPCRDMA: Fix FRMR registration/invalidate handling.
  RPCRDMA: Fix to XDR page base interpretation in marshalling logic.
  NFSv4: Send unmapped uid/gids to the server when using auth_sys
  NFSv4: Propagate the error NFS4ERR_BADOWNER to nfs4_do_setattr
  NFSv4: cleanup idmapper functions to take an nfs_server argument
  NFSv4: Send unmapped uid/gids to the server if the idmapper fails
  NFSv4: If the server sends us a numeric uid/gid then accept it
  NFSv4.1: reject zero layout with zeroed stripe unit
  ...

Documentation/filesystems/nfs/pnfs.txt

@@ -46,3 +46,10 @@ data server cache
 file driver devices refer to data servers, which are kept in a module
 level cache.  Its reference is held over the lifetime of the deviceid
 pointing to it.
+
+lseg
+----
+lseg maintains an extra reference corresponding to the NFS_LSEG_VALID
+bit which holds it in the pnfs_layout_hdr's list.  When the final lseg
+is removed from the pnfs_layout_hdr's list, the NFS_LAYOUT_DESTROYED
+bit is set, preventing any new lsegs from being added.