Use a cred from the nfs4_client->cl_state_owners list.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 In RFC3530, the RENEW operation is allowed to use either

 the same principal, RPC security flavour and (if RPCSEC_GSS), the same
  mechanism and service that was used for SETCLIENTID_CONFIRM

 OR

 Any principal, RPC security flavour and service combination that
 currently has an OPEN file on the server.

 Choose the latter since that doesn't require us to keep credentials for
 the same principal for the entire duration of the mount.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Use wait_on_bit() when waiting for state recovery to complete.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 A closer reading of RFC3530 reveals that OPEN_DOWNGRADE must always
 specify a access modes that have been the argument of a previous OPEN
 operation.
 IOW: doing OPEN(O_RDWR) and then OPEN_DOWNGRADE(O_WRONLY) is forbidden
 unless the user called OPEN(O_WRONLY)

 In order to fix that, we really need to track the three possible open
 states separately.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 RFC 3530 states that for OPEN_DOWNGRADE "The share_access and share_deny
 bits specified must be exactly equal to the union of the share_access and
 share_deny bits specified for some subset of the OPENs in effect for
 current openowner on the current file.

 Setattr is currently violating the NFSv4 rules for OPEN_DOWNGRADE in that
 it may cause a downgrade from OPEN4_SHARE_ACCESS_BOTH to
 OPEN4_SHARE_ACCESS_WRITE despite the fact that there exists no open file
 with O_WRONLY access mode.

 Fix the problem by replacing nfs4_find_state() with a modified version of
 nfs_find_open_context().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 We must not remove the nfs4_state structure from the inode open lists
 before we are in sequence lock.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Sacrifice queueing fairness for performance.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Storing a pointer to the struct rpc_task in the nfs_seqid is broken
 since the nfs_seqid may be freed well after the task has been destroyed.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Make NFSv4 return the fully initialized file pointer with the
 stateid that it created in the lookup w/intent.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Currently we fail to do so if the process was signalled.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 OPEN, CLOSE, etc no longer need these semaphores to ensure ordering of
 requests.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 NFSv4 file state-changing functions such as OPEN, CLOSE, LOCK,... are all
 labelled with "sequence identifiers" in order to prevent the server from
 reordering RPC requests, as this could cause its file state to
 become out of sync with the client.

 Currently the NFS client code enforces this ordering locally using
 semaphores to restrict access to structures until the RPC call is done.
 This, of course, only works with synchronous RPC calls, since the
 user process must first grab the semaphore.
 By dropping semaphores, and instead teaching the RPC engine to hold
 the RPC calls until they are ready to be sent, we can extend this
 process to work nicely with asynchronous RPC calls too.

 This patch adds a new list called "rpc_sequence" that defines the order
 of the RPC calls to be sent. We add one such list for each state_owner.
 When an RPC call is ready to be sent, it checks if it is top of the
 rpc_sequence list. If so, it proceeds. If not, it goes back to sleep,
 and loops until it hits top of the list.
 Once the RPC call has completed, it can then bump the sequence id counter,
 and remove itself from the rpc_sequence list, and then wake up the next
 sleeper.

 Note that the state_owner sequence ids and lock_owner sequence ids are
 all indexed to the same rpc_sequence list, so OPEN, LOCK,... requests
 are all ordered w.r.t. each other.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Ensure that lock owner structures are not released prematurely.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 From: Reuben Farrelly <reuben-lkml@reub.net>

 With gcc-4.0:

 fs/nfs/nfs4proc.c:2976: error: static declaration of
 'nfs4_file_inode_operations' follows non-static declaration
 fs/nfs/nfs4_fs.h:179: error: previous declaration of
 'nfs4_file_inode_operations' was here
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Add {get,set,list}xattr methods for nfs4.  The new methods are no-ops, to be
 used by subsequent ACL patch.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 - Move NFSv4 state definitions into a private header file.
 - Clean up gunk in nfs_fs.h
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>