We have no duplicate reply cache, so we always set the back channel
ca_maxresponsesize_cached to zero when negotiating the session.
That means we should always error out as soon as we see the server
set args->csa_cachethis.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

See RFC5661 Section 2.10.6.2: if retrying a request, and the old one is
still in progress, we must return NFS4ERR_DELAY as the reply to sequence.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Instead, use the values encoded in the slot table itself.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Peng Tao points out that the call to pnfs_mark_matching_lsegs_return()
could race with pnfs_put_lseg(), in which case the layout segment is
cleared, but no layoutreturn will be sent.
Fix is to replace the call to pnfs_mark_matching_lsegs_invalid().
Reported-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the layout segment is invalid, then we should not be adding more
write requests to the commit list. Instead, those writes should be
replayed after requesting a new layout.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The stateid is extremely valuable when debugging.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the client is promising to return the layout ASAP, then there is no
need to return DELAY and have the server retry. Instead default to the
normal procedure described in RFC5661.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The RFC requires us to check if the server is recalling a stateid that we
haven't yet received. If so, tell it to wait.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the client needs to delay the layout callback, then speed up the recall
process by marking the remaining layout segments to be actively returned
by the client.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This ensures that we don't reuse the stateid if a layout return or
implied layout return means that we've returned all layout segments
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It's not needed to checking NFS_DEBUG before define NFSDBG_FACILITY, remove it.
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Only support for single file layoutrecall for now.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

All these functions do is call nfs41_ping_server() without adding
anything.  Let's remove them and give nfs41_ping_server() a better name
instead.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Fix a callback slot table regression.

Fixes: e937ee71 ("nfs: Only update callback sequnce id when CB_SEQUENCE success")
Cc: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

For a cb_layoutrecall replay, nfsd got CB_SEQUENCE status of zero,
but all informations of cb_sequenceres are zero too !!!

validate_seqid() return NFS4ERR_RETRY_UNCACHED_REP for a replay,
and skip the initlize cb_sequenceres.
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When testing pnfs layout, nfsd got error NFS4ERR_SEQ_MISORDERED.
It is caused by nfs return NFS4ERR_DELAY before validate_seqid(),
don't update the sequnce id, but nfsd updates the sequnce id !!!

According to RFC5661 20.9.3,
" If CB_SEQUENCE returns an error, then the state of the slot
  (sequence ID, cached reply) MUST NOT change. "
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the server doesn't agree to out backchannel setup request, then
don't set one up.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Recent work in the pgio layer made it possible for there to be more than one
request per page. This caused a subtle change in commit behavior, because
write.c:nfs_commit_unstable_pages compares the number of *pages* waiting for
writeback against the number of requests on a commit list to choose when to
send a COMMIT in a non-blocking flush.

This is probably hard to hit in normal operation - you have to be using
rsize/wsize < PAGE_SIZE, or pnfs with lots of boundaries that are not page
aligned to have a noticeable change in behavior.
Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This code has been around for a while, but never was enabled, although
it is in a working shape.

Note that we implement NOTIFY_DEVICEID4_CHANGE identical to
NOTIFY_DEVICEID4_DELETE.  Given that in either case we can't do anything
but preventing further lookups of a given device ID there isn't much difference
in semantics for the two.  For the delete case the server MUST ensure that
there are no outstanding layouts, while for the change case it doesn't, but
that has little relevance to the client.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If a layout driver keeps per-inode state outside of the layout segments it
needs to be notified of any layout returns or recalls on an inode, and not
just about the freeing of layout segments.  Add a method to acomplish this,
which will allow the block layout driver to handle the case of truncated
and re-expanded files properly.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Expedite layout recall processing by forcing a layout commit when
we see busy segments.  Without it the layout recall might have to wait
until the VM decided to start writeback for the file, which can introduce
long delays.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the filehandles match, but the igrab() fails, or the layout is
freed before we can get it, then just return NULL.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It is not sufficient to compare filehandles when we receive a layout
recall from the server; we also need to check that the layout stateids
match.
Reported-by: Nshaobingqing <shaobingqing@bwstor.com.cn>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Clean up, since slot and sequence numbers are all unsigned anyway.

Among other things, squelch compiler warnings:

linux/fs/nfs/nfs4proc.c: In function ‘nfs4_setup_sequence’:
linux/fs/nfs/nfs4proc.c:703:2: warning: signed and unsigned type in
	conditional expression [-Wsign-compare]

and

linux/fs/nfs/nfs4session.c: In function ‘nfs4_alloc_slot’:
linux/fs/nfs/nfs4session.c:151:31: warning: signed and unsigned type in
	conditional expression [-Wsign-compare]
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Add tracepoints to nfs41_setup_sequence and nfs41_sequence_done
to track session and slot table state changes.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Set up tracepoints to track when delegations are set, reclaimed,
returned by the client, or recalled by the server.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

I found a few places that hardcode the minor version number rather than
making it dependent on the protocol the callback came in over.  This
patch makes it easier to add new minor versions in the future.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

On a CB_RECALL the callback service thread flushes the inode using
filemap_flush prior to scheduling the state manager thread to return the
delegation. When pNFS is used and I/O has not yet gone to the data server
servicing the inode, a LAYOUTGET can preceed the I/O. Unlike the async
filemap_flush call, the LAYOUTGET must proceed to completion.

If the state manager starts to recover data while the inode flush is sending
the LAYOUTGET, a deadlock occurs as the callback service thread holds the
single callback session slot until the flushing is done which blocks the state
manager thread, and the state manager thread has set the session draining bit
which puts the inode flush LAYOUTGET RPC to sleep on the forechannel slot
table waitq.

Separate the draining of the back channel from the draining of the fore channel
by moving the NFS4_SESSION_DRAINING bit from session scope into the fore
and back slot tables.  Drain the back channel first allowing the LAYOUTGET
call to proceed (and fail) so the callback service thread frees the callback
slot. Then proceed with draining the forechannel.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

The current code in pnfs_destroy_all_layouts() assumes that removing
the layout from the server->layouts list is sufficient to make it
invisible to other processes. This ignores the fact that most
users access the layout through the nfs_inode->layout...
There is further breakage due to lack of reference counting of the
layouts, meaning that the whole thing Oopses at the drop of a hat.

The code in initiate_bulk_draining() is almost correct, and can be
used as a model for pnfs_destroy_all_layouts(), so move that
code to pnfs.c, and refactor the code to allow us to choose between
a single filesystem bulk recall, and a recall of all layouts.
Also note that initiate_bulk_draining() currently calls iput() while
holding locks. Fix that too.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

Fix an inverted null pointer check in initiate_bulk_draining().
Signed-off-by: NNickolai Zeldovich <nickolai@csail.mit.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.7]

NFSv4.1 session management is getting complex enough to deserve
a separate file.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

RFC5661 requires us to make sure that the server knows we've updated
our slot table size by sending at least one SEQUENCE op containing the
new 'highest_slotid' value.
We can do so using the 'CHECK_LEASE' functionality of the state
manager.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The state manager no longer needs any special machinery to stop the
session flow and resize the slot table. It is all done on the fly by
the SEQUENCE op code now.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the server wants to leave us with only one slot, or it wants
to "shrink" our slot table to something larger than we have now,
then so be it.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Don't confuse the table size and the target_highest_slotid...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that the NFSv4.1 CB_RECALL_SLOT callback updates the slot table
target max slotid safely.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Dynamic slot allocation in NFSv4.1 depends on the client being able to
track the server's target value for the highest slotid in the
slot table.  See the reference in Section 2.10.6.1 of RFC5661.

To avoid ordering problems in the case where 2 SEQUENCE replies contain
conflicting updates to this target value, we also introduce a generation
counter, to track whether or not an RPC containing a SEQUENCE operation
was launched before or after the last update.

Also rename the nfs4_slot_table target_max_slots field to
'target_highest_slotid' to avoid confusion with a slot
table size or number of slots.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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