re[2]: [linux-lvm] [Q] LVM snapshot volume extendable?

[Greg Freemyer <freemyer@xxxxxxxxxxxxxxxxx>]

I agree, their seems to be a bug in LVM.

I am running XFS Version 1.2pre3 based on the 2.4.19 kernel and I cannot extend 
a LV with XFS fs on top.

In particular this works:

>>>
xfs_freeze -f /data                                                  (I don't 
have the patch installed)
lvcreate --snapshot -L 100M --name data_snap /dev/VG/data 
xfs_freeze -u /data                                                 (I don't 
have the patch installed)
mount -t xfs -o ro,nouuid /dev/VG/data_snap /data_snap
<<<

And this does not.

>>>
xfs_freeze -f /data                                                  (I don't 
have the patch installed)
lvcreate --snapshot -L 100M --name data_snap /dev/VG/data 
xfs_freeze -u /data                                                 (I don't 
have the patch installed)

lvdisplay /dev/VG/data_snap                                   (verified 0% used)
dd if=/dev/zero of=/data/dummy bs=1M count=75     (create a 75 Meg dummy file)
lvdisplay /dev/VG/data_snap                                   (verified approx 
75% used)
lvextend -L +100M /dev/VG/data_snap          
lvdisplay /dev/VG/data_snap                                   (verified approx 
37% used)

#  Everything looks fine, so I try to mount it

mount -t xfs -o ro,nouuid /dev/VG/data_snap /data_snap
mount: wrong fs type, bad option, bad superblock on 
/dev/TruStore-Data/data_snap,
       or too many mounted file systems
<<<


Greg Freemyer
The Norcross Group