[PATCH 0/1] NFSv4: deal with v4.0 servers that request confirmation on reclaim-type opens

[Scott Mayhew <smayhew@redhat.com>]

A Red Hat customer started having problems with open reclaims after a
kernel upgrade.  It turns out that the customer's NFS server is setting
the OPEN4_RESULT_CONFIRM in response to an OPEN(CLAIM_PREVIOUS), which
is not permitted by RFC 7530.

The client used to be able to handle that because nfs4_open_prepare() used
to copy the filehandle from the OPEN args to the OPEN results when doing
an open by filehandle.  That copy was removed by commit 4e2fcac77390
"nfsv4: Use correct inode in _nfs4_opendata_to_nfs4_state()".

It looks to me like adding the copy back in would not affect the
behavior of the nfs4_opendata_get_inode() helper that was added in
4e2fcac77390 (it uses the filehandle to look up the inode when doing an
open by name)... so this patch adds the copy back in and also adds a
warning in the event that the client does receive OPEN4_RESULT_CONFIRM
in response to an OPEN(CLAIM_PREVIOUS).

Scott Mayhew (1):
  NFSv4: deal with v4.0 servers that request confirmation on
    reclaim-type opens

 fs/nfs/nfs4proc.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

-- 
2.17.1