[dm-devel] Problem extending an "lv" with an active Snapshot

[Christian Robert]

Problem extending an "lv" with an active Snapshot

2.6.2 + udm2


to recreate:

# # create a test "lv"
# lvcreate -L2G -n test vg01
  Logical volume "test" created

# # format the "lv"
# mkreiserfs /dev/vg01/test
  [...]

# #create a Snapshot for the test "lv"
# lvcreate -s -L1G -n Stest /dev/vg01/test
  Logical volume "Stest" created

# mount /dev/vg01/test /mnt

# df /mnt
Filesystem                1K-blocks       Used  Available  Use%  Mounted
/dev/mapper/vg01-test       2097084      32840    2064244    2%  /mnt


# lvextend -L+1G /dev/vg01/test
  Extending logical volume test to 3.00 GB
  device-mapper ioctl cmd 9 failed: Invalid argument
  Couldn't load device 'vg01-Stest'.
  Problem reactivating test
# 

At this point the system is in strange state, trying to unmount /mnt
will lock the "umount" process. Even reboot don't work.


# lvdisplay /dev/vg01/{,S}test
  --- Logical volume ---
  LV Name                /dev/vg01/test
  VG Name                vg01
  LV UUID                ES5ear-aiRx-LwW9-5ZHn-uqwP-dmJI-O5Oxkk
  LV Write Access        read/write
  LV snapshot status     source of
                         /dev/vg01/Stest [active]
  LV Status              suspended
  # open                 2
  LV Size                3.00 GB
  Current LE             96
  Segments               2
  Allocation             next free (default)
  Read ahead sectors     0
  Block device           254:94
   
  --- Logical volume ---
  LV Name                /dev/vg01/Stest
  VG Name                vg01
  LV UUID                lmxkER-1rkc-Yzr6-js04-igpc-nAXn-d5SDmF
  LV Write Access        read/write
  LV snapshot status     active destination for /dev/vg01/test
  LV Status              suspended
  # open                 0
  LV Size                3.00 GB
  Current LE             96
  Segments               1
  Snapshot chunk size    8.00 KB
  Allocated to snapshot  0.00% 
  Allocation             next free (default)
  Read ahead sectors     0
  Block device           254:97
   



Now the question: Is it supposed to work ?  I know for sure that if 
                  I delete the snapshot before extending the "lv" 
                  it will work like a charm.

thanks,

Xtian.