On Sun, Apr 14 2019, Jes Sorensen wrote:
> On 3/25/19 7:24 PM, NeilBrown wrote:
>> On Mon, Mar 25 2019, Liwei Song wrote:
>>
>>> On 03/25/2019 07:43 AM, NeilBrown wrote:
>>>> On Tue, Mar 19 2019, Liwei Song wrote:
>>>>
>>>>> This rules will create link under /dev/disk/by-partuuid/ for
>>>>> MD devices partition, with which will support specify
>>>>> root=PARTUUID=XXX to boot rootfs.
>>>>>
>>>>> Signed-off-by: Liwei Song <liwei.song@xxxxxxxxxxxxx>
>>>>> ---
>>>>> udev-md-raid-arrays.rules | 1 +
>>>>> 1 file changed, 1 insertion(+)
>>>>>
>>>>> diff --git a/udev-md-raid-arrays.rules b/udev-md-raid-arrays.rules
>>>>> index c95ec7b1e4a9..5b99d5873ade 100644
>>>>> --- a/udev-md-raid-arrays.rules
>>>>> +++ b/udev-md-raid-arrays.rules
>>>>> @@ -30,6 +30,7 @@ IMPORT{builtin}="blkid"
>>>>> OPTIONS+="link_priority=100"
>>>>> OPTIONS+="watch"
>>>>> ENV{ID_FS_USAGE}=="filesystem|other|crypto", ENV{ID_FS_UUID_ENC}=="?*", SYMLINK+="disk/by-uuid/$env{ID_FS_UUID_ENC}"
>>>>> +ENV{ID_FS_USAGE}=="filesystem|other", ENV{ID_PART_ENTRY_UUID}=="?*", SYMLINK+="disk/by-partuuid/$env{ID_PART_ENTRY_UUID}"
>>>>> ENV{ID_FS_USAGE}=="filesystem|other", ENV{ID_FS_LABEL_ENC}=="?*", SYMLINK+="disk/by-label/$env{ID_FS_LABEL_ENC}"
>>>>>
>>>>> ENV{MD_LEVEL}=="raid[1-9]*", ENV{SYSTEMD_WANTS}+="mdmonitor.service"
>>>>> --
>>>>> 2.7.4
>>>>
>>>> This doesn't make any sense to me.
>>>> Presumably you want the by-partuuid link to point to a partition in the
>>>> array?
>>>
>>> Yes, That is what I want.
>>>
>>>> But this code will create a link pointing to the array.
>>>
>>> Because there is no ID_PART_ENTRY_UUID for the array, only partition in the array have
>>> such attribute，So in my case it will only create by-partuuid for a partition.
>>>
>>> For example, there is an md126 raid array,
>>>
>>> Disk /dev/md126: 44.2 GiB, 47501541376 bytes, 92776448 sectors
>>> Units: sectors of 1 * 512 = 512 bytes
>>> Sector size (logical/physical): 512 bytes / 512 bytes
>>> I/O size (minimum/optimal): 512 bytes / 512 bytes
>>> Disklabel type: gpt
>>> Disk identifier: 622CA1DE-A938-4704-98B0-5EAB0D3A7AAC
>>>
>>> Device Start End Sectors Size Type
>>> /dev/md126p1 2048 2000895 1998848 976M EFI System
>>> /dev/md126p2 2000896 88138671 86137776 41.1G Linux filesystem
>>> /dev/md126p3 88138672 92776414 4637743 2.2G Linux swap
>>>
>>>
>>>
>>> # udevadm info /dev/md126 |grep ID_PART_ENTRY_UUID
>>> this will get nothing since array do not have ID_PART_ENTRY_UUID.
>>>
>>> # udevadm info /dev/md126p1 |grep ID_PART_ENTRY_UUID
>>> E: ID_PART_ENTRY_UUID=018496b3-84e1-4c9f-864e-81650b21402f
>>> # udevadm info /dev/md126p2 |grep ID_PART_ENTRY_UUID
>>> E: ID_PART_ENTRY_UUID=2c1df1c5-41c8-42b4-a874-95dbf07820d5
>>> # udevadm info /dev/md126p3 |grep ID_PART_ENTRY_UUID
>>> E: ID_PART_ENTRY_UUID=bccde74f-efee-4b99-860c-998493d549a9
>>>
>>> it will create by-partuuid under /dev/disk/ for the partition in array
>>>
>>> # ls /dev/disk/by-partuuid/ -all
>>> lrwxrwxrwx 1 root root 13 Mar 22 03:33 018496b3-84e1-4c9f-864e-81650b21402f -> ../../md126p1
>>> lrwxrwxrwx 1 root root 13 Mar 22 03:33 2c1df1c5-41c8-42b4-a874-95dbf07820d5 -> ../../md126p2
>>> lrwxrwxrwx 1 root root 13 Mar 22 03:33 bccde74f-efee-4b99-860c-998493d549a9 -> ../../md126p3
>>>
>>> if my rootfs store in /dev/md126p2, then I can specify root=PARTUUID=2c1df1c5-41c8-42b4-a874-95dbf07820d5
>>> through command line to boot it.
>>>
>>
>> Thanks.
>> I was thinking that udev-md-raid-arrays.rule only dealt with the whole
>> array and that other files like 60-persistent-storage.rules dealt
>> with parititons, but I was wrong.
>> 60-persistent-storage.rules has
>> KERNEL!="loop*|mmcblk*[0-9]|msblk*[0-9]|mspblk*[0-9]|nvme*|sd*|sr*|vd*|xvd*|bcache*|cciss*|dasd*|ubd*|scm*|pmem*|nb>
>>
>> so it doesn't touch md array. And udev-md-raid-arrays.rules already has
>>
>> ENV{DEVTYPE}=="partition", ENV{MD_NAME}=="?*", SYMLINK+="disk/by-id/md-name-$env{MD_NAME}-part%n", OPTIONS+="string_escape=replace"
>> ENV{DEVTYPE}=="partition", ENV{MD_UUID}=="?*", SYMLINK+="disk/by-id/md-uuid-$env{MD_UUID}-part%n"
>> ENV{DEVTYPE}=="partition", ENV{MD_DEVNAME}=="*[^0-9]", SYMLINK+="md/$env{MD_DEVNAME}%n"
>> ENV{DEVTYPE}=="partition", ENV{MD_DEVNAME}=="*[0-9]", SYMLINK+="md/$env{MD_DEVNAME}p%n"
>>
>> so it does handle partitions of md array.
>>
>> So yes, your patch does make sense.
>>
>> Reviewed-by: NeilBrown <neilb@xxxxxxxx>
>
> Trying to catch up here, so the conclusion was the original patch was
> good, correct?
Correct!
NeilBrown
>
> Thanks,
> Jes
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