NFSv4: Add attribute update barriers to delegreturn and pNFS layoutcommit

Ensure that other operations that race with delegreturn and layoutcommit
cannot revert the attribute updates that were made on the server.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
1 file changed