Re: NILFS2: double uuid

[Heinz Diehl <htd+ml@fritha.org>]

On 08.06.2015, Heinz Diehl wrote: 

To be more precise, here's what works and what don't, in detail
(and after a fresh install of Arch):

The USB memory is xfs formatted and works fine:

[root@alarmpi /]# lsblk -f
NAME        FSTYPE LABEL UUID                                 MOUNTPOINT
sda                                                           
`-sda1      xfs          ff17dda9-fcae-42e7-a438-9087de58902e 
mmcblk0                                                       
|-mmcblk0p1 vfat         EA5B-4477                            /boot
`-mmcblk0p2 ext4         c4ddc925-15ab-4465-ac78-967a845e98d5 /


Now, it's nilfs2 formatted:

[root@alarmpi /]# mkfs.nilfs2 /dev/sda1
WARNING: Device /dev/sda1 appears to contain an existing xfs superblock.
WARNING: All data will be lost after format!

DO YOU REALLY WANT TO FORMAT DEVICE /dev/sda1?

Continue? [y/N] y
mkfs.nilfs2 (nilfs-utils 2.2.3)
Start writing file system initial data to the device
       Blocksize:4096  Device:/dev/sda1  Device Size:32026656768
File system initialization succeeded !! 

After that, all seems to be ok. lsblk shown no double uuid:

[root@alarmpi /]# lsblk -f
NAME        FSTYPE LABEL UUID                                 MOUNTPOINT
sda                                                           
`-sda1      nilfs2       98da384c-392e-4551-98c0-d076524f5d8b 
mmcblk0                                                       
|-mmcblk0p1 vfat         EA5B-4477                            /boot
`-mmcblk0p2 ext4         c4ddc925-15ab-4465-ac78-967a845e98d5 /
[root@alarmpi /]# 


Now the USB drive gets manually mounted, all is ok:

[root@alarmpi /]# mount /dev/sda1 /USBDRIVE
[root@alarmpi /]# lsblk -f
NAME        FSTYPE LABEL UUID                                 MOUNTPOINT
sda                                                           
`-sda1      nilfs2       98da384c-392e-4551-98c0-d076524f5d8b /USBDRIVE
mmcblk0                                                       
|-mmcblk0p1 vfat         EA5B-4477                            /boot
`-mmcblk0p2 ext4         c4ddc925-15ab-4465-ac78-967a845e98d5 /


Now, the newly formatted drive is registered in fstab to be
automatically mounted on boot:

UUID=ff17dda9-fcae-42e7-a438-9087de58902e	/USBDRIVE	nilfs2	defaults	0	0

After rebooting the machine, nothing is mounted, and lsblk shows the
double uuid:

[root@alarmpi /]# lsblk -f
NAME        FSTYPE LABEL UUID                                 MOUNTPOINT
sda                      98da384c-392e-4551-98c0-d076524f5d8b 
`-sda1      nilfs2       98da384c-392e-4551-98c0-d076524f5d8b
mmcblk0                                                       
|-mmcblk0p1 vfat         EA5B-4477                            /boot
`-mmcblk0p2 ext4         c4ddc925-15ab-4465-ac78-967a845e98d5 /

The logs say:

Jun 08 11:23:47 alarmpi mount: mount.nilfs2: Error while mounting /dev/sda on /USBDRIVE: Device or resource busy
Jun 08 11:23:47 alarmpi systemd: Failed to mount /USBDRIVE.

Here it becomes clear what happens: the system wants to mount /dev/sda
rather than /dev/sda1, and thus fails.

Out of curiosity, I tried both xfs, ext4 and btrfs, and all of them
just work.

Thanks,
Heinz.