Re: [PATCH] udev rules: introduce rules for cluster-md to confirm device

[Guoqing Jiang <gqjiang@suse.com>]

On 08/01/2017 12:40 PM, NeilBrown wrote:
> On Tue, Aug 01 2017, Guoqing Jiang wrote:
>
>> For cluster scenario, add device is different with native raid.
>> When a node issues adds a device, then the node will broadcast
>> a message with UUID to other nodes in the cluster. If receiving
>> node can find the device with the specific UUID, it must confirm
>> the device, otherwise reports it is missing.
>>
>> Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
>> ---
>>   Makefile                               |  6 ++++--
>>   udev-md-clustered-confirm-device.rules | 20 ++++++++++++++++++++
>>   2 files changed, 24 insertions(+), 2 deletions(-)
>>   create mode 100644 udev-md-clustered-confirm-device.rules
>>
>> diff --git a/Makefile b/Makefile
>> index 021d3ad..0977f27 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -256,8 +256,10 @@ install-man: mdadm.8 md.4 mdadm.conf.5 mdmon.8
>>   	$(INSTALL) -D -m 644 md.4 $(DESTDIR)$(MAN4DIR)/md.4
>>   	$(INSTALL) -D -m 644 mdadm.conf.5 $(DESTDIR)$(MAN5DIR)/mdadm.conf.5
>>   
>> -install-udev: udev-md-raid-arrays.rules udev-md-raid-assembly.rules udev-md-raid-creating.rules
>> -	@for file in 01-md-raid-creating.rules 63-md-raid-arrays.rules 64-md-raid-assembly.rules ; \
>> +install-udev: udev-md-raid-arrays.rules udev-md-raid-assembly.rules udev-md-raid-creating.rules \
>> +		udev-md-clustered-confirm-device.rules
>> +	@for file in 01-md-raid-creating.rules 63-md-raid-arrays.rules 64-md-raid-assembly.rules \
>> +		69-md-clustered-confirm-device.rules ; \
>>   	do sed -e 's,BINDIR,$(BINDIR),g' udev-$${file#??-} > .install.tmp.1 && \
>>   	   $(ECHO) $(INSTALL) -D -m 644 udev-$${file#??-} $(DESTDIR)$(UDEVDIR)/rules.d/$$file ; \
>>   	   $(INSTALL) -D -m 644 .install.tmp.1 $(DESTDIR)$(UDEVDIR)/rules.d/$$file ; \
>> diff --git a/udev-md-clustered-confirm-device.rules b/udev-md-clustered-confirm-device.rules
>> new file mode 100644
>> index 0000000..d763e27
>> --- /dev/null
>> +++ b/udev-md-clustered-confirm-device.rules
>> @@ -0,0 +1,20 @@
>> +# do not edit this file, it will be overwritten on update
>> +
>> +SUBSYSTEM!="block", GOTO="clustermd_end"
>> +
>> +# handle md arrays
>> +KERNEL!="md*", GOTO="clustermd_end"
>> +ENV{DEVTYPE}!="disk", GOTO="clustermd_end"
>> +
>> +# Based on the received UUID, node confirms the device if
>> +# it is found by blkid, otherwise the node reports it is
>> +# missing.
>> +ACTION=="change", ENV{EVENT}=="ADD_DEVICE", ENV{DEVICE_UUID}=="?*", ENV{RAID_DISK}=="?*", \
>> +PROGRAM="BINDIR/blkid -o device -t UUID_SUB=$env{DEVICE_UUID}", RESULT!="", \
>> +RUN+="BINDIR/mdadm --manage $env{DEVNAME} --cluster-confirm $env{RAID_DISK}:$result"
>> +
>> +ACTION=="change", ENV{EVENT}=="ADD_DEVICE", ENV{DEVICE_UUID}=="?*", ENV{RAID_DISK}=="?*", \
>> +PROGRAM="BINDIR/blkid -o device -t UUID_SUB=$env{DEVICE_UUID}", RESULT=="", \
>> +RUN+="BINDIR/mdadm --manage $env{DEVNAME} --cluster-confirm $env{RAID_DISK}:missing"
>> +
>> +LABEL="clustermd_end"
>> -- 
>> 2.10.0
> This can run "blkid" twice, which seems wasteful.
> I think it would be best to skip to the end if ACTION != "change" and if
> event != ADD_DEVICE etc.
> Then
>   PROGRAM="BINDIR/blkid -o device -t UUID_SUB=$env{DEVICE_UUID}", ENV{".mdadm.blkid"} = "$result"
>
> Then have two rules which tests ENV{".mdadm.blkid"} and run one of the
> two mdadm commands.

Thanks for the suggestion! I will send v2 soon.

Cheers,
Guoqing