It turns out that nfs4_proc_get_root() may return raw NFSv4 errors instead of
mapping them to kernel errors.  Problem spotted by Neil Horman
<nhorman@tuxdriver.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

 Upon return of a write delegation, the server will almost always bump the
 change attribute. Ensure that we pick up that change so that we don't
 invalidate our data cache unnecessarily.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 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>

 Cut down on the number of unnecessary RENEW requests on the wire.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

 In order to allow users to interrupt/cancel it.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Get rid of some unnecessary intermediate structures
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 When recovering from a delegation recall or a network partition, we need
 to replay open(O_RDWR), open(O_RDONLY) and open(O_WRONLY) separately.
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>

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

 OPEN is a stateful operation, so we must ensure that it always
 completes. In order to allow users to interrupt the operation,
 we need to make the RPC call asynchronous, and then wait on
 completion (or cancel).
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Cleanup in preparation for making OPEN calls interruptible by the user.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

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

 Shrink the RPC task structure. Instead of storing separate pointers
 for task->tk_exit and task->tk_release, put them in a structure.

 Also pass the user data pointer as a parameter instead of passing it via
 task->tk_calldata. This enables us to nest callbacks.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 - Missing initialisation of attribute bitmask in _nfs4_proc_write()
 - On success, _nfs4_proc_write() must return number of bytes written.
 - Missing post_op_update_inode() in _nfs4_proc_write()
 - Missing initialisation of attribute bitmask in _nfs4_proc_commit()
 - Missing post_op_update_inode() in _nfs4_proc_commit()
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 When caching locks due to holding a file delegation, we must always
 check against local locks before sending anything to the server.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Now that we have a method of dealing with delegation recalls, actually
 enable the caching of posix and BSD locks.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Delegations allow us to cache posix and BSD locks, however when the
 delegation is recalled, we need to "flush the cache" and send
 the cached LOCK requests to the server.

 This patch sets up the mechanism for doing so.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Ensure that we retry the failed operation...
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>

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

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

 Optimise attribute revalidation when hardlinking. Add post-op attributes
 for the directory and the original inode.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 "Optional" means that the close call will not fail if the getattr
 at the end of the compound fails.
 If it does succeed, try to refresh inode attributes.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Since the directory attributes change every time we CREATE a file,
 we might as well pick up the new directory attributes in the same
 compound.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Since we almost always call nfs_end_data_update() after we called
 nfs_refresh_inode(), we now end up marking the inode metadata
 as needing revalidation immediately after having updated it.

 This patch rearranges things so that we mark the inode as needing
 revalidation _before_ we call nfs_refresh_inode() on those operations
 that need it.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

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

 resp_len is passed in as buffer size to decode routine; make sure it's
 set right in case where userspace provides less than a page's worth of
 buffer.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 If the server is in the unconfirmed OPEN state for a given open owner
 and receives a second OPEN for the same open owner, it will cancel the
 state of the first request and set up an OPEN_CONFIRM for the second.

 This can cause a race that is discussed in rfc3530 on page 181.

 The following patch allows the client to recover by retrying the
 original open request.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 Unless of course the open fails due to permission issues.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

 Since it appears that some servers don't...
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>