[PATCH v2 3/2 nvme-cli] fabrics: re-read the discovery log page when a discovery controller reconnected

[Sagi Grimberg]

When using persistent discovery controllers, if the discovery controller
loses connectivity and manage to reconnect after a while, we need to
retrieve again the discovery log page in order to learn about possible
changes that may have occurred during this time as discovery log change
events were lost.

Upon reception of a udev EVENT=rediscover we can kickstart discovery on
the existing discovery controller device node that generated the event.

Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
---
 nvmf-autoconnect/udev-rules/70-nvmf-autoconnect.rules.in | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/nvmf-autoconnect/udev-rules/70-nvmf-autoconnect.rules.in b/nvmf-autoconnect/udev-rules/70-nvmf-autoconnect.rules.in
index 434cc080ffe3..93e438863672 100644
--- a/nvmf-autoconnect/udev-rules/70-nvmf-autoconnect.rules.in
+++ b/nvmf-autoconnect/udev-rules/70-nvmf-autoconnect.rules.in
@@ -17,3 +17,10 @@ ACTION=="change", SUBSYSTEM=="nvme", ENV{NVME_AEN}=="0x70f002",\
 ACTION=="change", SUBSYSTEM=="fc", ENV{FC_EVENT}=="nvmediscovery", \
   ENV{NVMEFC_HOST_TRADDR}=="*",  ENV{NVMEFC_TRADDR}=="*", \
   RUN+="@SYSTEMCTL@ --no-block start nvmf-connect at --device=none\t--transport=fc\t--traddr=$env{NVMEFC_TRADDR}\t--trsvcid=none\t--host-traddr=$env{NVMEFC_HOST_TRADDR}.service"
+
+# A discovery controller just (re)connected, re-read the discovery log change to
+# check if there were any changes since it was last connected.
+ACTION=="change", SUBSYSTEM=="nvme", ENV{NVME_EVENT}=="rediscover", ATTR{cntrltype}=="discovery", \
+  ENV{NVME_TRTYPE}=="*", ENV{NVME_TRADDR}=="*", \
+  ENV{NVME_TRSVCID}=="*", ENV{NVME_HOST_TRADDR}=="*", \
+  RUN+="@SYSTEMCTL@ --no-block start nvmf-connect at --device=$kernel\t--transport=$env{NVME_TRTYPE}\t--traddr=$env{NVME_TRADDR}\t--trsvcid=$env{NVME_TRSVCID}\t--host-traddr=$env{NVME_HOST_TRADDR}.service"
-- 
2.34.1