Bug 710618

This issue most likely exists in RHEL6.1 as well.

First bug is in lvreduce (I've not looked beyond that).  Reproduced with upstream code.  vg_validate() needs fixing to detect metadata corruption like this as well.

When it hit the error:
   Segment extent reduction 57not divisible by #stripes 7
it should have either aborted the operation (or rounded the size to something compatible, maybe earlier in the code) instead of carrying on and writing out corrupted metadata.

(1) fix vg_validate to ensure that if a segment is mirrored, the size of every mimage matches

(2) fix lvreduce to abort if it gets that error instead of ignoring it

(3) fix the rounding logic to check all segments and round the size appropriately (common factor logic) - the only difficult part of this fix

Item (1) should be sufficient to avoid the corruption; item (2) gives a clean error; item (3) makes the command work as intended.

reproducer: lvcreate -i2; lvconvert -m1; lvreduce -l1 then compare LSize in lvs -a

I'll add at least 1) + 2) to 5.7 so it cannot corrupt VG metadata.

Fixed in
lvm2-2.02.84-5.el5
lvm2-cluster-2.02.84-5.el5

full fix included.

Roundig up logic hopefully fixed in lvm2-2.02.84-6.el5

Fix verified in the latest rpms.

2.6.18-266.el5

lvm2-2.02.84-6.el5    BUILT: Thu Jun 16 10:31:15 CDT 2011
lvm2-cluster-2.02.84-6.el5    BUILT: Thu Jun 16 10:32:56 CDT 2011
device-mapper-1.02.63-3.el5    BUILT: Thu May 19 08:09:22 CDT 2011
device-mapper-event-1.02.63-3.el5    BUILT: Thu May 19 08:09:22 CDT 2011
cmirror-1.1.39-10.el5    BUILT: Wed Sep  8 16:32:05 CDT 2010
kmod-cmirror-0.1.22-3.el5    BUILT: Tue Dec 22 13:39:47 CST 2009


[root@taft-01 ~]# pvcreate /dev/sd[bc][12356]
  Physical volume "/dev/sdb1" successfully created
  Physical volume "/dev/sdb2" successfully created
  Physical volume "/dev/sdb3" successfully created
  Physical volume "/dev/sdb5" successfully created
  Physical volume "/dev/sdb6" successfully created
  Physical volume "/dev/sdc1" successfully created
  Physical volume "/dev/sdc2" successfully created
  Physical volume "/dev/sdc3" successfully created
  Physical volume "/dev/sdc5" successfully created
  Physical volume "/dev/sdc6" successfully created
[root@taft-01 ~]# vgcreate grant /dev/sd[bc][12356]
  Volume group "grant" successfully created
[root@taft-01 ~]# lvcreate -L 1G --stripes 7 --stripesize 512 -n stripe grant
  Rounding size (256 extents) up to stripe boundary size (259 extents)
  Logical volume "stripe" created
[root@taft-01 ~]# lvs -a -o +devices
  LV       VG     Attr   LSize  Devices
  stripe   grant  -wi-a-  1.01G /dev/sdb1(0),/dev/sdb2(0),/dev/sdb3(0),/dev/sdb5(0),/dev/sdb6(0),/dev/sdc1(0),/dev/sdc2(0)
[root@taft-01 ~]# lvconvert -m 1 grant/stripe
  grant/stripe: Converted: 0.4%
  grant/stripe: Converted: 25.1%
  grant/stripe: Converted: 50.2%
  grant/stripe: Converted: 75.7%
  grant/stripe: Converted: 100.0%
[root@taft-01 ~]# lvs -a -o +devices
  LV                VG     Attr   LSize  Log         Copy%  Devices
  stripe            grant  mwi-a-  1.01G stripe_mlog 100.00 stripe_mimage_0(0),stripe_mimage_1(0)
  [stripe_mimage_0] grant  iwi-ao  1.01G                    /dev/sdb1(0),/dev/sdb2(0),/dev/sdb3(0),/dev/sdb5(0),/dev/sdb6(0),/dev/sdc1(0),/dev/sdc2(0)
  [stripe_mimage_1] grant  iwi-ao  1.01G                    /dev/sdc3(0)
  [stripe_mlog]     grant  lwi-ao  4.00M                    /dev/sdc6(0)
[root@taft-01 ~]# lvdisplay grant/stripe | grep Current
  Current LE             259
[root@taft-01 ~]#  lvreduce -f -l 202 grant/stripe
  Rounding size (202 extents) up to stripe boundary size for segment (203 extents)
  WARNING: Reducing active logical volume to 812.00 MB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
  Reducing logical volume stripe to 812.00 MB
  Logical volume stripe successfully resized
[root@taft-01 ~]#  echo $?
0
[root@taft-01 ~]# lvdisplay grant/stripe | grep Current
  Current LE             203
[root@taft-01 ~]# lvextend -l 241 grant/stripe
  Extending 2 mirror images.
  Using stripesize of last segment 512.00 KB
  Rounding size (241 extents) down to stripe boundary size for segment (238 extents)
  Extending logical volume stripe to 952.00 MB
  Not enough PVs with free space available for parallel allocation.
  Consider --alloc anywhere if desperate.
[root@taft-01 ~]# lvs -a -o +devices
  LV                VG     Attr   LSize   Log         Copy%  Devices
  stripe            grant  mwi-a- 812.00M stripe_mlog 100.00 stripe_mimage_0(0),stripe_mimage_1(0)
  [stripe_mimage_0] grant  iwi-ao 812.00M                    /dev/sdb1(0),/dev/sdb2(0),/dev/sdb3(0),/dev/sdb5(0),/dev/sdb6(0),/dev/sdc1(0),/dev/sdc2(0)
  [stripe_mimage_1] grant  iwi-ao 812.00M                    /dev/sdc3(0)
  [stripe_mlog]     grant  lwi-ao   4.00M                    /dev/sdc6(0)
[root@taft-01 ~]# vgchange -an grant
  0 logical volume(s) in volume group "grant" now active
[root@taft-01 ~]# lvremove grant
  Logical volume "stripe" successfully removed

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2011-1071.html

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2011-1071.html