[PATCH v4 0/7] Client-side OFFLOAD_STATUS implementation

[cel@kernel.org]

From: Chuck Lever <chuck.lever@oracle.com>

SCSI implementation experience has shown that an interrupt-only
COPY offload implementation is not reliable. There are too many
common scenarios where the client can miss the completion interrupt
(in our case, this is an NFSv4.2 CB_OFFLOAD callback).

Therefore, a polling mechanism is needed. The NFSv4.2 protocol
provides one in the form of the its OFFLOAD_STATUS operation. Linux
NFSD implements OFFLOAD_STATUS already. This series adds a Linux NFS
client implementation of the OFFLOAD_STATUS operation that can query
the state of a background COPY on the server.

These patches are also available here:

https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/log/?h=fix-async-copy

Changes since v3:
- Change to fixed lease_time/2 timeout before posting OFFLOAD_STATUS
- Check if CB_OFFLOAD arrived if OFFLOAD_STATUS returned BAD_STATEID
- Added Olga's R-b and T-b tags

Chuck Lever (7):
  NFS: CB_OFFLOAD can return NFS4ERR_DELAY
  NFS: Fix typo in OFFLOAD_CANCEL comment
  NFS: Rename struct nfs4_offloadcancel_data
  NFS: Implement NFSv4.2's OFFLOAD_STATUS XDR
  NFS: Implement NFSv4.2's OFFLOAD_STATUS operation
  NFS: Use NFSv4.2's OFFLOAD_STATUS operation
  NFS: Refactor trace_nfs4_offload_cancel

 fs/nfs/callback_proc.c    |   2 +-
 fs/nfs/nfs42proc.c        | 195 ++++++++++++++++++++++++++++++++++----
 fs/nfs/nfs42xdr.c         |  88 ++++++++++++++++-
 fs/nfs/nfs4proc.c         |   3 +-
 fs/nfs/nfs4trace.h        |  11 ++-
 fs/nfs/nfs4xdr.c          |   1 +
 include/linux/nfs4.h      |   1 +
 include/linux/nfs_fs_sb.h |   1 +
 include/linux/nfs_xdr.h   |   5 +-
 9 files changed, 282 insertions(+), 25 deletions(-)

-- 
2.47.0