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>
Thanks,
NeilBrown
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