[PATCH rfc 0/6] support traddr as dns names for ip based transports

[Sagi Grimberg <sagi@grimberg.me>]

Currently nvme-cli is able to resolve an ip address from a dns name if
traddr argument was given as a dns name, so it does that and passes down
to the kernel the resolved ip address.

However, if the dns resolution changes over time, the kernel will not
be able to reconnect because it has a stale ip address. While this is
not a real use case for nvme subsystems, it could be a valid use-case
for discovery controllers, where the resolution is made from a dns
name that may load-balance/failover over multiple endpoints.

The last patch (7/6) is for libnvme to pass down the traddr as a dns
name if the kernel supports dns queries.

The inspiration was taken from the nfs client that does this for
redirects or locations discovery.

It is an rfc, so feedback is welcome.

Sagi Grimberg (6):
  nvme-fabrics: add helper to resolve ipv4/ipv6 or dns name
  nvme-tcp: use nvmf_resolve_address helper
  nvme-tcp: re-resolve traddr upon reconnect in case it is a dns name
  nvme-rdma: use nvmf_resolve_address helper
  nvme-rdma: re-resolve traddr upon reconnect in case it is a dns name
  nvme-fabrics: expose support for traddr as dns names to userspace

 drivers/nvme/host/fabrics.c | 29 +++++++++++++++++++++++++++++
 drivers/nvme/host/fabrics.h |  2 ++
 drivers/nvme/host/rdma.c    | 21 +++++++++++++--------
 drivers/nvme/host/tcp.c     | 21 +++++++++++++--------
 4 files changed, 57 insertions(+), 16 deletions(-)

-- 
2.41.0