[PATCH 0/3] pNFS/flexfiles: mirror instance error handling

[Benjamin Coddington <ben.coddington@hammerspace.com>]

When a flexfiles data server fails, the client marks the layout for return
and cancels the layout segment's in-flight I/O.  ff_layout_cancel_io()
cancels I/O to every mirror instance rather than just the failed one, and
cancelling a request that has already been transmitted does not stop the
data server from executing it.  Those writes may complete after the client
has sent its LAYOUTRETURN, and the metadata server will see writes to a file
for which no write layout is outstanding.

Patch 1 reports the operation the client was preparing to send when a
data server connection fails, instead of OP_ILLEGAL.

Patches 2 and 3 let a layout driver cancel I/O to a single device, and
pass the failed device down from the flexfiles error paths, so that I/O
to the remaining mirrors drains before the LAYOUTRETURN is sent.

Layout recalls that set clora_changed, bulk returns and revocations are
unchanged: they continue to cancel I/O to every device.

Benjamin Coddington (3):
  NFSv4/flexfiles: report the intended opnum when DS connection setup
    fails
  pNFS: allow layout drivers to cancel I/O to a single device
  NFSv4/flexfiles: only cancel I/O to a failed mirror instance

 fs/nfs/blocklayout/blocklayout.c          |  6 +++--
 fs/nfs/callback_proc.c                    |  2 +-
 fs/nfs/filelayout/filelayout.c            |  4 +--
 fs/nfs/flexfilelayout/flexfilelayout.c    | 29 ++++++++++++--------
 fs/nfs/flexfilelayout/flexfilelayout.h    |  2 +-
 fs/nfs/flexfilelayout/flexfilelayoutdev.c | 17 +++++++-----
 fs/nfs/pnfs.c                             | 32 ++++++++++++++---------
 fs/nfs/pnfs.h                             | 14 ++++++----
 8 files changed, 64 insertions(+), 42 deletions(-)

-- 
2.53.0