We'll add test cases for this to the regression suite.

add_areas_line() is trying to detect if a partial activation is pointless, but is only looking at one segment in isolation.

1) The test needs to consider the LV as a whole - check all segments at once, not each individually.

2) If all areas used by a segment are missing, the whole segment should be mapped to an error target.

From call: if it is easier to revert patch to reintroduce previous state, let's do it for 6.3.

And fix it properly upstream.

Peter, I think it was your patch causing this problem, can you take a look? THX.

Should be split into two.

(a) revert this from upstream/RHEL6.3:

               if (!num_existing_areas &&
                   !strstr(seg->lv->name, "_mimage_") &&
                   !((name = strstr(seg->lv->name, "_mlog")) && !name[5])) {
                       log_error("Cannot activate %s/%s: all segments missing."
                                 seg->lv->vg->name, seg->lv->name);
                       return 0;

(b) new bug for upstream/RHEL6.4 to deal with the issue properly (comment #2)

http://www.redhat.com/archives/lvm-devel/2012-May/msg00024.html

Fix verified in the latest rpms.

2.6.32-270.el6.x86_64
lvm2-2.02.95-9.el6    BUILT: Wed May 16 10:34:14 CDT 2012
lvm2-libs-2.02.95-9.el6    BUILT: Wed May 16 10:34:14 CDT 2012
lvm2-cluster-2.02.95-9.el6    BUILT: Wed May 16 10:34:14 CDT 2012
udev-147-2.41.el6    BUILT: Thu Mar  1 13:01:08 CST 2012
device-mapper-1.02.74-9.el6    BUILT: Wed May 16 10:34:14 CDT 2012
device-mapper-libs-1.02.74-9.el6    BUILT: Wed May 16 10:34:14 CDT 2012
device-mapper-event-1.02.74-9.el6    BUILT: Wed May 16 10:34:14 CDT 2012
device-mapper-event-libs-1.02.74-9.el6    BUILT: Wed May 16 10:34:14 CDT 2012
cmirror-2.02.95-9.el6    BUILT: Wed May 16 10:34:14 CDT 2012

[root@taft-01 ~]# vgcreate test /dev/sd[bc][1]
  Volume group "test" successfully created

[root@taft-01 ~]# lvcreate -n lv -l100%FREE  test
  Logical volume "lv" created

[root@taft-01 ~]# lvs -a -o +devices
  LV  VG    Attr     LSize    Devices         
  lv  test  -wi-a--- 271.33g  /dev/sdb1(0)    
  lv  test  -wi-a--- 271.33g  /dev/sdc1(0)    

[root@taft-01 ~]# vgchange -a n test
  0 logical volume(s) in volume group "test" now active

[root@taft-01 ~]# dd if=/dev/zero of=/dev/sdb1 bs=1M count=1
1+0 records in
1+0 records out
1048576 bytes (1.0 MB) copied, 0.0115695 s, 90.6 MB/s

[root@taft-01 ~]# vgscan
  Reading all physical volumes.  This may take a while...
  Couldn't find device with uuid egskWs-Zx5i-DQwE-x1B4-tamM-jeOh-wfphE5.
  Found volume group "test" using metadata type lvm2
  Found volume group "vg_taft01" using metadata type lvm2

[root@taft-01 ~]# lvs -o +devices test
  Couldn't find device with uuid egskWs-Zx5i-DQwE-x1B4-tamM-jeOh-wfphE5.
  LV   VG   Attr     LSize   Devices          
  lv   test -wi----- 271.33g unknown device(0)
  lv   test -wi----- 271.33g /dev/sdc1(0)     

[root@taft-01 ~]# vgchange -a y test --partial
  Partial mode. Incomplete logical volumes will be processed.
  Couldn't find device with uuid egskWs-Zx5i-DQwE-x1B4-tamM-jeOh-wfphE5.
  1 logical volume(s) in volume group "test" now active

[root@taft-01 ~]# dmsetup table |grep test
test-lv: 0 284508160 linear 253:3 0
test-lv: 284508160 284508160 linear 8:33 2048
test-lv-missing_0_0: 0 284508160 error

    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
No documentation 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/RHBA-2012-0962.html