1366460 – When "pool-build --overwrite" a block device as a whole partition with filesystem=ext2/ext3/ext4/vfat, it will fail because libvirt call "mkfs" command without "-F/-I"(Force)

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Bug 1366460 - When "pool-build --overwrite" a block device as a whole partition with filesystem=ext2/ext3/ext4/vfat, it will fail because libvirt call "mkfs" command without "-F/-I"(Force)

Summary: When "pool-build --overwrite" a block device as a whole partition with filesy...

Keywords:
Status:	CLOSED ERRATA
Alias:	None
Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	libvirt
Sub Component:
Version:	7.3
Hardware:	x86_64
OS:	Linux
Priority:	medium
Severity:	medium
Target Milestone:	rc
Target Release:	---
Assignee:	John Ferlan
QA Contact:	Pei Zhang
Docs Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+	depends on / blocked

Reported:	2016-08-12 03:59 UTC by yisun
Modified:	2017-08-01 23:53 UTC (History)
CC List:	6 users (show)
Fixed In Version:	libvirt-2.5.0-1.el7
Doc Type:	No Doc Update
Doc Text:	undefined
Clone Of:
Environment:
Last Closed:	2017-08-01 17:11:42 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)

Links
System	ID	Private	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHEA-2017:1846	0	normal	SHIPPED_LIVE	libvirt bug fix and enhancement update	2017-08-01 18:02:50 UTC

Description yisun 2016-08-12 03:59:29 UTC

Description:
When "pool-build --overwrite" a block device as a whole partition with filesystem=ext2/ext3/ext4/vfat, it will fail because libvirt call "mkfs" command without "-F/-I"(Force)

Versions:
libvirt-2.0.0-5.el7.x86_64

How reproducible:
100%



Steps:
please note, the "Force" option for mkfs.vfat is "-I", for mkfs.ext2/3/4 is "-F" and for mkfs.xfs is "-f"
 
1. I used a usb disk in my test.
# lsscsi
[7:0:0:0]    disk    SanDisk  Cruzer Blade     1.26  /dev/sdg


2. mkfs the sdg as xfs file system.
# mkfs.xfs /dev/sdg -f

3. prepare a pool's xml as follow:
# cat fs.pool
<pool type='fs'>
  <name>fs</name>
  <uuid>5c7433cf-acf3-4c36-8300-65d5b2a18d01</uuid>
  <capacity unit='bytes'>0</capacity>
  <allocation unit='bytes'>0</allocation>
  <available unit='bytes'>0</available>
  <source>
    <device path='/dev/sdg'/>
    <format type='ext4'/>   <======= here can be ext4/ext3/ext2/vfat
  </source>
  <target>
    <path>/var/lib/libvirt/images/fs</path>
  </target>
</pool>

4. Define the pool
# virsh pool-define fs.pool
Pool fs defined from fs.pool

5. try to build the pool with --overwrite
# virsh pool-build fs --overwrite
error: Failed to build pool fs
error: Failed to make filesystem of type 'ext4' on device '/dev/sdg': Success


6. now, in libvirtd.log, we can see libvirt try to use "/usr/sbin/mkfs -t ext4 /dev/sdg"
#cat /var/log/libvirtd-debug.log
...
2016-08-11 11:15:16.932+0000: 3819: debug : virCommandRunAsync:2429 : About to run /usr/sbin/mkfs -t ext4 /dev/sdg
...

7. check the /dev/sdg
# parted /dev/sdg p
Model: SanDisk Cruzer Blade (scsi)
Disk /dev/sdg: 8004MB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number  Start  End     Size    File system  Flags
 1      0.00B  8004MB  8004MB  xfs <==== still xfs


Expected result:
with --overwrite option, pool-build should successfully mkfs the whole block device. As above step 6, if libvirt use "/usr/sbin/mkfs -t ext3 -F /dev/sdg" (a "-F" added"), the pool-build should be successful.

Actual result:
pool-build failed (and error message is strange with a "Success")


Additional info:
pool-build --overwrite a xfs pool is ok because the mkfs cmd has a "-f"
# tailf /var/log/libvirtd-debug.log  | grep xfs
2016-08-11 10:55:11.520+0000: 3819: debug : virStorageBackendMakeFileSystem:763 : source device: '/dev/sdg' format: 'xfs'
2016-08-11 10:55:11.520+0000: 3819: debug : virCommandRunAsync:2429 : About to run /usr/sbin/mkfs -t xfs -f /dev/sdg

Comment 1 John Ferlan 2016-11-15 20:40:13 UTC

Patch posted:

http://www.redhat.com/archives/libvir-list/2016-November/msg00782.html

Comment 2 John Ferlan 2016-11-16 12:09:46 UTC

Now pushed:

$ git show
commit 135e77d32fe9e7299f5c82757563e5a6d28e2f3c
Author: John Ferlan <jferlan>
Date:   Tue Nov 15 15:29:47 2016 -0500

    fs: Add proper switch to create filesystem with overwrite
...
    When using the --overwrite switch on a pool-build or pool-create, the
    The mkfs.ext{2|3|4} commands use mke2fs which requires using the '-F' switch
    in order to force overwriting the current filesystem on the whole disk.
    
    Likewise, the mkfs.vfat command uses mkfs.fat which requires using the '-I'
    switch in order to force overwriting the current filesystem on the whole disk.


$ git describe 135e77d32fe9e7299f5c82757563e5a6d28e2f3c
v2.4.0-154-g135e77d
$

Comment 4 Pei Zhang 2017-02-16 06:01:45 UTC

Version :
libvirt-3.0.0-2.el7.x86_64
qemu-kvm-rhev-2.8.0-4.el7.x86_64

Verified steps :

1. Prepare a disk 
# lsscsi
[15:0:0:0]   disk    LIO-ORG  target4          4.0   /dev/sdb 

2. make the sdb as xfs file system.
# mkfs.xfs /dev/sdb -f

3.Prepare a pool's xml with format type is ext4 :
# cat fspool.xml 
<pool type='fs'>
  <name>fs</name>
  <uuid>5c7433cf-acf3-4c36-8300-65d5b2a18d01</uuid>
  <capacity unit='bytes'>0</capacity>
  <allocation unit='bytes'>0</allocation>
  <available unit='bytes'>0</available>
  <source>
    <device path='/dev/sdb'/>
    <format type='ext4'/>   
  </source>
  <target>
    <path>/var/lib/libvirt/images/fs</path>
  </target>
</pool>

4. Define the pool
# virsh pool-define fspool.xml 
Pool fs defined from fspool.xml

5. Build the pool with --overwrite, build successfully
# virsh pool-build fs --overwrite
Pool fs built

6. Check the block device, the file system was changed tp ext4 successfully. 
# parted /dev/sdb p
......
Number  Start  End     Size    File system  Flags
 1      0.00B  32.2GB  32.2GB  ext4

7. using pool-edit gto change the format to ext3
# virsh pool-edit fs
Pool fs XML configuration edited.

8. build agian with --overwrite

# virsh pool-build fs --overwrite
Pool fs built

9. Check the block device, the file system was changed to ext3 successfully
# parted /dev/sdb p
......
Number  Start  End     Size    File system  Flags
 1      0.00B  32.2GB  32.2GB  ext3

10. Trying to change format to ext2/vfat. They also can be changed successfully.

As above, move this bug to verified.

Comment 5 errata-xmlrpc 2017-08-01 17:11:42 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHEA-2017:1846

Comment 6 errata-xmlrpc 2017-08-01 23:53:19 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHEA-2017:1846

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