Bug 702260

One more CLI example, this time LV name is q-rhel in the same 



[root@dhcp-29-7 ~]# virsh vol-delete --pool root_vg q-rhel
chyba:Failed to delete vol q-rhel
chyba:vnitřní chyba '/sbin/lvremove -f /dev/root_vg/q-rhel' exited with non-zero status 5 and signal 0:   Can't remove open logical volume "q-rhel"


[root@dhcp-29-7 ~]# lvchange -an /dev/root_vg/q-rhel 
[root@dhcp-29-7 ~]# virsh vol-delete --pool root_vg q-rhel
Vol q-rhel deleted

This looks like a  bug / race condition in the lvremove command to me. It is non-deterministic when I run it 

[root@lettuce ~]# virsh vol-delete --pool HostVG foo
error: Failed to delete vol foo
error: internal error '/sbin/lvremove -f /dev/HostVG/foo' exited with non-zero status 5 and signal 0:   LV HostVG/foo in use: not deactivating
  Unable to deactivate logical volume "foo"


[root@lettuce ~]# virsh vol-delete --pool HostVG foo
error: Failed to delete vol foo
error: internal error '/sbin/lvremove -f /dev/HostVG/foo' exited with non-zero status 5 and signal 0:   LV HostVG/foo in use: not deactivating
  Unable to deactivate logical volume "foo"


[root@lettuce ~]# virsh vol-delete --pool HostVG foo
Vol foo deleted

libvirt explicitly uses the '-f' argument to ensure active volumes are removed

 "  -f, --force
      Remove active logical volumes without confirmation."

(In reply to comment #2)
> This looks like a  bug / race condition in the lvremove command to me. It is
> non-deterministic when I run it 
> 

It seems so, but doing a 'lvchange -an $LV' seems to be pretty viable workaround (numbers printed are numbers of retries before LV got removed), -f option isn't needed at all:


[root@dhcp-29-7 ~]# for I in {1..20};do virsh vol-create-as root_vg lv-example 25G --allocation 0 --format raw >/dev/null ; i=0; until lvremove -f /dev/root_vg/lv-example >/dev/null 2>&1; do i=$(($i+1)); done ; echo $i ; virsh pool-refresh root_vg >/dev/null;done
19
9
4
1
2
4
0
10
7
19
2
1
13
0
0
1
6
14
2
3
[root@dhcp-29-7 ~]# for I in {1..20};do virsh vol-create-as root_vg lv-example 25G --allocation 0 --format raw >/dev/null ; i=0; until { lvchange -an /dev/root_vg/lv-example; lvremove /dev/root_vg/lv-example >/dev/null 2>&1; } ; do i=$(($i+1)); done ; echo $i ; virsh pool-refresh root_vg >/dev/null;done
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

This is race of lvremove, see BZ https://bugzilla.redhat.com/show_bug.cgi?id=570359, patch was applied in lvm upstream, https://www.redhat.com/archives/lvm-devel/2011-May/msg00025.html, but the patch can't fix the problem drastically, it just can minimize the possiability to reproduce the problem.

Both lvremove and "lvchange -an" invoke function "deactivate_lv(cmd, lv))" to deactive the lv, so using "lvchange -an" won't work for problem as <a href="https://bugzilla.redhat.com/show_bug.cgi?id=702260#c2">#c2</a>.

Using "lvremove" will work for David's case though, as lvremove do checking before deactive the lv to ensure the lv is not referred to by another existing LVs.

<quote>

        if (lv_info(cmd, lv, 0, &info, 1, 0)) {
                if (info.open_count) {
                        log_error("Can't remove open logical volume \"%s\"",
                                  lv->name);
                        return 0;
                }

                if (lv_is_active(lv) && (force == PROMPT) &&
                    lv_is_visible(lv) &&
                    yes_no_prompt("Do you really want to remove active "
                                  "%slogical volume %s? [y/n]: ",
                                  vg_is_clustered(vg) ? "clustered " : "",
                                  lv->name) == 'n') {
                        log_error("Logical volume %s not removed", lv->name);
                        return 0;
                }
        }
        
        /* Skipped codes here */

        if (!deactivate_lv(cmd, lv)) {
                log_error("Unable to deactivate logical volume \"%s\"",
                          lv->name);
                return 0;
        }
</quote>

I'm wondering if libvirt should use "lvchange -an" before "lvremove", as it at least could fix David's problem.

Patch posted to upstream

http://www.redhat.com/archives/libvir-list/2011-September/msg00802.html

patch committed to upstream.

Verify this bug with:
libvirt-0.9.9-1.el6.x86_64


1) add vg in the libvirt pool 

# virsh pool-dumpxml vg_inteli7124
<pool type='logical'>
  <name>vg_inteli7124</name>
  <uuid>794ac3ee-3a62-d96b-db6d-4c4857269cbb</uuid>
  <capacity>499579355136</capacity>
  <allocation>284264759296</allocation>
  <available>215314595840</available>
  <source>
    <device path='/dev/sda2'/>
    <name>vg_inteli7124</name>
    <format type='lvm2'/>
  </source>
  <target>
    <path>/dev/vg_inteli7124</path>
    <permissions>
      <mode>0700</mode>
      <owner>-1</owner>
      <group>-1</group>
    </permissions>
  </target>
</pool>

2) add volume 
# virsh vol-create-as --pool vg_inteli7124 --name lv_test --capacity 100M
Vol lv_test created

3)  check vol list 
# virsh vol-list  vg_inteli7124
Name                 Path                                    
-----------------------------------------
lv_home              /dev/vg_inteli7124/lv_home              
lv_root              /dev/vg_inteli7124/lv_root              
lv_swap              /dev/vg_inteli7124/lv_swap              
lv_test              /dev/vg_inteli7124/lv_test

4)  remove the volume 
#virsh vol-delete --pool vg_inteli7124 lv_test
Vol lv_test deleted

#virsh vol-list vg_inteli7124
Name                 Path                                    
-----------------------------------------
lv_home              /dev/vg_inteli7124/lv_home              
lv_root              /dev/vg_inteli7124/lv_root              
lv_swap              /dev/vg_inteli7124/lv_swap

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No documentaion needed.

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.

http://rhn.redhat.com/errata/RHSA-2012-0748.html