clean up f_op- files
writeback: remove .nonblocking and .encountered_congestion

Remove two unused struct writeback_control fields:

	.encountered_congestion	(completely unused)
	.nonblocking		(never set, checked/showed in XFS,NFS/btrfs)

The .for_background check in nfs_write_inode() is also removed btw,
as .for_background implies WB_SYNC_NONE.

Reviewed-by: Jan Kara <jack@suse.cz>
Proposed-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
NFS: fix return value of nfs_pagein_one/nfs_flush_one

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: Don't use DATA_SYNC writes

If we're writing back data, and the FLUSH_STABLE flag is set, then we
always want to use NFS_FILE_SYNC, since we're always in a situation where
we're doing page reclaim, and so we want to free up the page as quickly
as possible.

If we're in the FLUSH_COND_STABLE case, then we either want to use another
unstable write (if we have to do a commit anyway) or again, we want to
use NFS_FILE_SYNC because we know that we have no more pages to write
out.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: pnfs IPv6 support

Handle ipv6 remote addresses from GETDEVICEINFO

 - supports netid "tcp" for ipv4 and "tcp6" for ipv6 as rfc 5665 specifies
 - added ds_remotestr to avoid having to handle different AFs in every dprintk
 - tested against pynfs 4.1 server, submitting ipv6 support patch to pynfs
 - tested with IPv6 disabled, it compiles cleanly and relies on rpc_pton to
   refuse to accept IPv6 addresses

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: Parse and store all multipath DS addresses

This parses and stores all addresses associated with each data server,
laying the groundwork for supporting multipath to data servers.

 - Skips over addresses that cannot be parsed (ie IPv6 addrs if v6 is not
   enabled).  Only fails if none of the addresses are recognizable
 - Currently only uses the first address that parsed cleanly
 - Tested against pynfs server (modified to support multipath)

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: pnfs: loop over multipath addrs on connect

Don't just use the first addr in the multipath list - instead, loop
over addresses when calling nfs4_set_ds_client() (which calls connect)
until it is successful.

Although this is not real multipath support, it's a quick fix to handle when
an MDS sends a list of addresses for a DS and some of the addr families are
unsupported or misconfigured (like no routable ipv6 addr assigned).
This will attempt all paths to the DS before giving up, instead of immediately
falling back to the MDS.

As before, an error encountered after a successful connect() will cause all
i/o to fall back to the MDS.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: use scope from exchange_id to skip reclaim

can be skipped if the "eir_server_scope" from the exchange_id proc differs from
previous calls.

Also, in the future server_scope will be useful for determining whether client
trunking is available

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: fix comment

We support IPv4 and IPv6 now.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: move pnfs layouts to nfs_server structure

Layouts should be tracked per nfs_server (aka superblock)
instead of per struct nfs_client, which may have multiple FSIDs associated
with it.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: Add SECINFO_NO_NAME procedure

If the client is using NFS v4.1, then we can use SECINFO_NO_NAME to find
the secflavor for the initial mount.  If the server doesn't support
SECINFO_NO_NAME then I fall back on the "guess and check" method used
for v4.0 mounts.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: Added TEST_STATEID call

This patch adds in the xdr for doing a TEST_STATEID call with a single
stateid. RFC 5661 allows multiple stateids to be tested in a single
call, but only testing one keeps things simpler for now.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: added FREE_STATEID call

FREE_STATEID is used to tell the server that we want to free a stateid
that no longer has any locks associated with it.  This allows the client
to reclaim locks without encountering edge conditions documented in
section 8.4.3 of RFC 5661.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: test and free stateids during recovery

When recovering open files and locks, the stateid should be tested
against the server and freed if it is invalid.  This patch adds new
recovery functions for NFS v4.1.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFS: Cleanup of the nfs_pageio code in preparation for a pnfs bugfix

We need to ensure that the layouts are set up before we can decide to
coalesce requests. To do so, we want to further split up the struct
nfs_pageio_descriptor operations into an initialisation callback, a
coalescing test callback, and a 'do i/o' callback.

This patch cleans up the existing callback methods before adding the
'initialisation' callback.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv4.1: Add an initialisation callback for pNFS

Ensure that we always get a layout before setting up the i/o request.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv4.1: Fall back to ordinary i/o through the mds if we have no layout segment

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv4.1: Clean ups for the device id cache

The fact that the global device id cache holds a reference to the
nfs4_deviceid_node until it is invisible to rcu lookups implies that
we can always assume that the reference count is non-zero in
_find_get_deviceid.

Also clean up nfs4_put_deviceid_node and the removal of the device id
from the cache.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv4.1: File layout only supports whole file layouts

Ask for whole file layouts. Until support for layout segments is fully
supported in the file layout code, discard non-whole file layouts.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv4.1: Clean up layoutreturn

Since we take a reference to it, we really ought to pass the a pointer to
the layout header in the arguments instead of assuming that
NFS_I(inode)->layout will forever point to the correct object.

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