[linux-lvm] hard-lock seems to have caused serious LVM problems

[<dmeyer@dmeyer.net>]

Last night, my machine (running Linux-2.4.0, LVM-0.9, and the 0.9
utilities) locked up hard.  On reboot, vgscan can only find one of my
VGs.  vgscan results in:

# vgscan
vgscan -- reading all physical volumes (this may take a while...)
vgscan -- found active volume group "main_vg"
vgscan -- found inactive volume group "misc_vg"
vgscan -- ERROR "vg_read_with_pv_and_lv(): allocated LE of LV" can't get data of volume group "misc_vg" from physical volume(s)
vgscan -- ERROR "vg_read_with_pv_and_lv(): allocated LE of LV"
creating "/etc/lvmtab" and "/etc/lvmtab.d"

The LV on main_vg works just fine, but I can't get at anything in
misc_vg.

vgcfgrestore isn't helping.  I get:
# vgcfgrestore -v -f ./lvmconf/misc_vg.conf -n misc_vg -l
vgcfgrestore -- locking logical volume manager
vgcfgrestore -- restoring volume group "misc_vg" from "./lvmconf/misc_vg.conf"
vgcfgrestore -- checking existence of "./lvmconf/misc_vg.conf"
vgcfgrestore -- reading volume group data for "misc_vg" from "./lvmconf/misc_vg.conf"
vgcfgrestore -- ERROR: different structure size stored in "./lvmconf/misc_vg.conf" than expected in file vg_cfgrestore.c [line 120]
vgcfgrestore -- ERROR "vg_cfgrestore(): read" restoring volume group "misc_vg"

Hacking in some extra debugging code, it looks like the first
VGCFG_READ in vgcfgrestore() is expecting a vg_t to be 2484 bytes, but
the actual struct on-disk is only 2248 bytes.

All other diagnostic output is going to be too long for the list, so
please look at http://www.dmeyer.net/~dmeyer/lvm for files I reference
below. 

As far as I can tell (which isn't very far, really), the PVs
themselves are OK - I can run pvdata and get nothing that looks (to
me, at least) horribly suspicious.  I put the results from pvdata -a
for all 5 PVs in pvdata.<partition>.

vgscan -d seg faults.  However, by adding

   if (uuidstr[0] != '/') {
     return -1;
   }

to the beginning of lvm_check_uuid in lvm_uuid.c, I managed to keep
vgscan from dying on me.  Anyway, the results from vgscan -d are also
on my web page.  There are actually 4 versions:  0.9 and 0.9.1-beta1,
and both patched (i.e. with the code above) and unpatched.

I've also dd'd the first 32k of each of the 5 file partitions, in case
that might help.  Also, /etc/lvm* from the previous night's backups
are also there.

If anyone can suggest a course of action, I'd really appreciate it.

     Dave