1. 10 Feb, 2008 1 commit
    • Jeff Layton's avatar
      NLM: set RPC_CLNT_CREATE_NOPING for NLM RPC clients · 031fd3aa
      Jeff Layton authored
      It's currently possible for an unresponsive NLM client to completely
      lock up a server's lockd. The scenario is something like this:
      
      1) client1 (or a process on the server) takes a lock on a file
      2) client2 tries to take a blocking lock on the same file and
         awaits the callback
      3) client2 goes unresponsive (plug pulled, network partition, etc)
      4) client1 releases the lock
      
      ...at that point the server's lockd will try to queue up a GRANT_MSG
      callback for client2, but first it requeues the block with a timeout of
      30s. nlm_async_call will attempt to bind the RPC client to client2 and
      will call rpc_ping. rpc_ping entails a sync RPC call and if client2 is
      unresponsive it will take around 60s for that to time out. Once it times
      out, it's already time to retry the block and the whole process repeats.
      
      Once in this situation, nlmsvc_retry_blocked will never return until
      the host starts responding again. lockd won't service new calls.
      
      Fix this by skipping the RPC ping on NLM RPC clients. This makes
      nlm_async_call return quickly when called.
      Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
      Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
      031fd3aa
  2. 06 Feb, 2008 31 commits
  3. 05 Feb, 2008 8 commits