lib/host: disk_is_available function only validates mounted disks and not others

[rushikeshjadhav]

In following case, disk_is_available('sdb') returns True which should not be the case.

xcp-ng-tests/lib/host.py

Line 467 in 358665a

def disk_is_available(self, disk):

[18:26 xcp-ng-xs1 ~]# lsblk 
NAME                                                                                     MAJ:MIN  RM   SIZE RO TYPE MOUNTPOINT
sdb                                                                                        8:16    0   500G  0 disk 
├─linstor_group-thin_device_tmeta                                                        253:1     0   128M  0 lvm  
│ └─linstor_group-thin_device-tpool                                                      253:3     0 499.8G  0 lvm  
│   ├─linstor_group-thin_device                                                          253:4     0 499.8G  0 lvm  
│   └─linstor_group-xcp--persistent--database_00000                                      253:5     0     1G  0 lvm  
│     └─drbd1000                                                                         147:1000  0     1G  0 disk 
└─linstor_group-thin_device_tdata                                                        253:2     0 499.8G  0 lvm  
  └─linstor_group-thin_device-tpool                                                      253:3     0 499.8G  0 lvm  
    ├─linstor_group-thin_device                                                          253:4     0 499.8G  0 lvm  
    └─linstor_group-xcp--persistent--database_00000                                      253:5     0     1G  0 lvm  
      └─drbd1000                                                                         147:1000  0     1G  0 disk 
sr0                                                                                       11:0     1  1024M  0 rom  
sdc                                                                                        8:32    0   500G  0 disk 
sda                                                                                        8:0     0    50G  0 disk 
├─sda4                                                                                     8:4     0   512M  0 part 
├─sda2                                                                                     8:2     0    18G  0 part 
├─sda5                                                                                     8:5     0     4G  0 part /var/log
├─sda3                                                                                     8:3     0   8.5G  0 part 
│ └─XSLocalEXT--8900cca8--706a--d7f2--447b--bff4129333a3-8900cca8--706a--d7f2--447b--bff4129333a3
                                                                                         253:0     0   8.5G  0 lvm  /run/sr-mount/8900cca8-706a-d7f2-447b-bff4129333a3
├─sda1                                                                                     8:1     0    18G  0 part /
└─sda6                                                                                     8:6     0     1G  0 part [SWAP]

[Wescoeur]

In fact this function checks if a disk is mounted. If a filesystem is configured on it, we consider that we can use the disk, for DRBD it is perhaps a bit more restrictive. I suppose we could explicitly check if DRBDs are present. But in the case of a LVM VG we consider that the disk is free, which is not very symmetrical.

[rushikeshjadhav]

In fact this function checks if a disk is mounted. If a filesystem is configured on it, we consider that we can use the disk, for DRBD it is perhaps a bit more restrictive. I suppose we could explicitly check if DRBDs are present. But in the case of a LVM VG we consider that the disk is free, which is not very symmetrical.

I see that this function checks whether a disk is available for use (i.e., not mounted). The code further does not use the disks that have any mountpoint associated with them.

    def disk_is_available(self, disk):
        return len(self.ssh(['lsblk', '-n', '-o', 'MOUNTPOINT', '/dev/' + disk]).strip()) == 0

I was thinking to use blkid /dev/disk in here instead of lsblk. blkid returns 2 if there is nothing on the disk e.g. LVM, gpt, etc. hence marking disk_is_available.

e.g.

[22:35 xcp-ng-xs1 ~]# blkid /dev/sda
/dev/sda: PTTYPE="gpt" 
[22:35 xcp-ng-xs1 ~]# blkid /dev/sdb
/dev/sdb: UUID="OAcOvb-o0bE-etIW-m3Zk-Pf29-GCe3-92hVt4" TYPE="LVM2_member"