[linux-lvm] XFS device-mapper problem

["Frank J. Buchholz" <frankb@ercwc.org>]

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Hello,

Recently I attemped to 'lvextend' a logical volume.  My fatal error was 
that I had a typo in my prior 'vgextend' command in which I added 
/dev/sda to a volume that already held /dev/sda1. One the device for the 
disk (sda) and the other being the device for the only partition on the 
disk (sda1). Oh no!

I recieved the following error during the 'lvextend' command...
lvm> lvextend -L+1G /dev/Volume00/LogVol00
  Extending logical volume LogVol00 to 2.93 TB
  device-mapper ioctl cmd 9 failed: Invalid argument
  Couldn't load device 'Volume00-LogVol00'.
  Problem reactivating LogVol00

I have since 'lvreduce'd the logical volume back to its original size 
and 'vgreduce'd the volume by removing /dev/sda from the volume.  Both 
of these commands ran well without any noticable errors.

However my problem is that I believe I have corrupted the block device 
located at /dev/mapper.  The block device in that directory is 
Volume00-LogVol00.  The filesystem is XFS.  When I run xfs_check on the 
filesystem I recieve the following error:
xfs_check /dev/Volume00/LogVol00
xfs_check: /dev/Volume00/LogVol00 is invalid (cannot read first 512 bytes)

When I run:
# hexdump -C Volume00-LogVol00
#
It simply returns nothing except a prompt.

The directory listing looks like:
# pwd
/dev/mapper
#ls -l
crw-------  1 root root  10, 63 Nov 22 12:05 control
brw-------  1 root root 253,  1 Jun 17  2003 Volume00-LogVol00
brw-------  1 root root 253,  0 Nov 22 10:03 Volume01-LogVol00

Volume01 is a working block device while Volume00 seems to have stopped 
working. 

I can 'hexdump' /dev/sda1, the physical volume device in Volume00, and 
it shows me the content of the filesystem (phew, still there).

How do I fix LVM and device-mapper to make this work again?

Thanks,
Frank

-- 
Frank J. Buchholz




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