From: Olga Kornievskaia <kolga@netapp.com>
To: <bfields@redhat.com>
CC: <linux-nfs@vger.kernel.org>
Subject: [RFC v1 00/17] NFSD support for inter+async COPY 
Date: Thu, 2 Mar 2017 11:01:24 -0500
Message-ID: <20170302160142.30413-1-kolga@netapp.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-nfs-owner@vger.kernel.org

This is server-side support for NFSv4.2 inter and async COPY which is
on top of existing intra sync COPY. It also depends on the NFS client
piece for NFSv4.2 to do client side of the destination server piece
in the inter SSC.

NFSD determines if COPY is intra or inter and if sync or async. For
inter, NSFD uses NFSv4.1 protocol and creates an internal mount point
(superblock). It will destroy the mount point when copy is done.

To do asynchronous copies, NFSD creates a single threaded workqueue
and does not tie up an NFSD thread to complete the copy. Upon receiving
the COPY, it generates a unique copy stateid (stores a global list
for keeping track of state for OFFLOAD_STATUS to be queried by),
queues up a workqueue for the copy, and replies back to the client.
nfsd4_copy arguments that are allocated on the stack are copied for
the work item.

In the async copy handler, it calls into VFS copy_file_range() with
4MB chunks and loops until it completes the requested copy size. If
error is encountered it's saved but also we save the amount of data
copied so far. Once done, the results are queued for the callback
workqueue and sent via CB_OFFLOAD. Also currently, choosing to clean
up the copy state information stored in the global list when cope is
done and not doing it when callback's release function (it could be
done there alternatively if needed it?).

On the source server, upon receiving a COPY_NOTIFY, it generate a
unique stateid that's kept in the global list. Upon receiving a READ
with a stateid, the code checks the normal list of open stateid and
now additionally, it'll check the copy state list as well before
deciding to either fail with BAD_STATEID or find one that matches.
The stored stateid is only valid to be used for the first time
with a choosen lease period (90s currently). When the source server
received an OFFLOAD_CANCEL, it will remove the stateid from the
global list. Otherwise, the copy stateid is removed upon the removal
of its "parent" stateid (open/lock/delegation stateid).


Andy Adamson (7):
  NFSD add ca_source_server<> to COPY
  NFSD generalize nfsd4_compound_state flag names
  NFSD: allow inter server COPY to have a STALE source server fh
  NFSD return nfs4_stid in nfs4_preprocess_stateid_op
  NFSD add COPY_NOTIFY operation
  NFSD add nfs4 inter ssc to nfsd4_copy
  NFSD Unique stateid_t for inter server to server COPY authentication

Olga Kornievskaia (10):
  NFSD CB_OFFLOAD xdr
  NFSD OFFLOAD_STATUS xdr
  NFSD OFFLOAD_CANCEL xdr
  NFSD xdr callback stateid in async COPY reply
  NFSD first draft of async copy
  NFSD handle OFFLOAD_CANCEL op
  NFSD stop queued async copies on client shutdown
  NFSD create new stateid for async copy
  NFSD define EBADF in nfserrno
  NFSD support OFFLOAD_STATUS

 fs/nfsd/Kconfig        |  10 +
 fs/nfsd/netns.h        |   8 +
 fs/nfsd/nfs4callback.c |  95 +++++++
 fs/nfsd/nfs4proc.c     | 704 ++++++++++++++++++++++++++++++++++++++++++++++---
 fs/nfsd/nfs4state.c    | 142 +++++++++-
 fs/nfsd/nfs4xdr.c      | 266 ++++++++++++++++++-
 fs/nfsd/nfsctl.c       |   2 +
 fs/nfsd/nfsd.h         |   2 +
 fs/nfsd/nfsproc.c      |   1 +
 fs/nfsd/state.h        |  32 ++-
 fs/nfsd/xdr4.h         |  53 +++-
 fs/nfsd/xdr4cb.h       |  10 +
 include/linux/nfs4.h   |   1 +
 13 files changed, 1273 insertions(+), 53 deletions(-)

-- 
1.8.3.1