Bug 1400135

Summary:	blkid is unable to detect filesystem on thinly provisioned lvm member
Product:	[Fedora] Fedora	Reporter:	James Hogarth <james.hogarth>
Component:	util-linux	Assignee:	Karel Zak <kzak>
Status:	CLOSED DUPLICATE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	25	CC:	jonathan, kzak, lpol, qe-baseos-daemons
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Clone Of:	1400060	Environment:
Last Closed:	2017-01-06 11:35:58 UTC	Type:	Bug
Regression:	---	Mount Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description James Hogarth 2016-11-30 13:59:14 UTC

+++ This bug was initially created as a clone of Bug #1400060 +++

Description of problem:
When using a thinly provisioned LVM member blkid is unable to detect the filesystem and report data such as UUID

Version-Release number of selected component (if applicable):
libblkid-2.28.2-1.fc25.x86_64
util-linux-2.28.2-1.fc25.x86_64

How reproducible:
Always

Steps to Reproduce:
1. lvcreate -n full -l 10%FREE vg_myvg
2. lvcreate -n tp -T -l 10%FREE vg_myvg
3. mkfs.xfs /dev/vg_myvg/full
4. mkfs.xfs /dev/vg_myvg/tp
5. blkid /dev/vg_myvg/full
6. blkid /dev/vg_myvg/tp

Actual results:
Nothing returned by blkid

Expected results:
UUID and type to be returned by blkid, so no difference in behaviour between thinly provisioned and full

Additional info:
This also behaves the same with other filesystems such as ext4 so is not an xfs issue specifically.

Using xfs_admin or dumpe2fs against the TP LVM member does display the expected data.

Comment 1 James Hogarth 2016-11-30 15:49:06 UTC

Note that this prevents mounting a thinly provisioned LVM member by UUID as well:

[root@c7-multidisktest ~]# mount /home/jenkins/
mount: can't find UUID=a99a213f-6af6-4707-a597-6fee02bd2b31
[root@c7-multidisktest ~]# lsblk
NAME                         MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda                            8:0    0   20G  0 disk 
├─sda1                         8:1    0  500M  0 part /boot
└─sda2                         8:2    0 19.5G  0 part 
  ├─centos_c7--template-root 253:0    0 17.5G  0 lvm  /
  └─centos_c7--template-swap 253:1    0    2G  0 lvm  [SWAP]
sdb                            8:16   0   20G  0 disk 
└─sdb1                         8:17   0   20G  0 part 
  ├─vg_data-jenkins_tmeta    253:2    0   12M  0 lvm  
  │ └─vg_data-jenkins        253:4    0   10G  0 lvm  
  ├─vg_data-jenkins_tdata    253:3    0   10G  0 lvm  
  │ └─vg_data-jenkins        253:4    0   10G  0 lvm  
  └─vg_data-testdata         253:5    0    5G  0 lvm  /mnt/testdata1
sdc                            8:32   0   60G  0 disk 
└─sdc1                         8:33   0   60G  0 part /mnt/testdata2
[root@c7-multidisktest ~]# lvs
  LV       VG                 Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root     centos_c7-template -wi-ao---- 17.47g                                                    
  swap     centos_c7-template -wi-ao----  2.00g                                                    
  jenkins  vg_data            twi-a-tz-- 10.00g             0.00   0.62                            
  testdata vg_data            -wi-ao----  4.98g                                                    
[root@c7-multidisktest ~]# xfs_admin -u /dev/vg_data/jenkins 
UUID = a99a213f-6af6-4707-a597-6fee02bd2b31
[root@c7-multidisktest ~]# blkid /dev/vg_data/jenkins 
[root@c7-multidisktest ~]#

Comment 2 Karel Zak 2017-01-06 11:35:58 UTC


*** This bug has been marked as a duplicate of bug 1400060 ***