NFSv4.1: Handle EXCHGID4_FLAG_CONFIRMED_R during NFSv4.1 migration
authorChuck Lever <chuck.lever@oracle.com>
Thu, 8 Jun 2017 15:52:44 +0000 (11:52 -0400)
committerAnna Schumaker <Anna.Schumaker@Netapp.com>
Thu, 13 Jul 2017 20:00:12 +0000 (16:00 -0400)
commit8dcbec6d20eb881ba368d0aebc3a8a678aebb1da
tree403e867311961dce6e0b680b34d6bf7e8526617c
parent1f541895dae956df0be14a3190f507b601ac3fcc
NFSv4.1: Handle EXCHGID4_FLAG_CONFIRMED_R during NFSv4.1 migration

Transparent State Migration copies a client's lease state from the
server where a filesystem used to reside to the server where it now
resides. When an NFSv4.1 client first contacts that destination
server, it uses EXCHANGE_ID to detect trunking relationships.

The lease that was copied there is returned to that client, but the
destination server sets EXCHGID4_FLAG_CONFIRMED_R when replying to
the client. This is because the lease was confirmed on the source
server (before it was copied).

Normally, when CONFIRMED_R is set, a client purges the lease and
creates a new one. However, that throws away the entire benefit of
Transparent State Migration.

Therefore, the client must not purge that lease when it is possible
that Transparent State Migration has occurred.

Reported-by: Xuan Qi <xuan.qi@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Xuan Qi <xuan.qi@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
fs/nfs/nfs4client.c
fs/nfs/nfs4state.c
include/linux/nfs_fs_sb.h