[linux-lvm] Extend/Reduce snapshot not updating VG's used PE count.
Heinz J . Mauelshagen
mauelshagen at sistina.com
Mon May 6 08:33:02 UTC 2002
have integrated this one and probably found the bug for the wrong PE count
after reboot (VG reactivation) as well.
Testing now. Soon to be in CVS.
Heinz -- The LVM Guy --
On Wed, May 01, 2002 at 07:55:04AM -0700, Stephenson, Dale wrote:
> I've noticed that extending or reducing a snapshot doesn't seem to affect
> the used PE count of its volume group (as shown in places like
> /proc/lvm/global). I haven't noticed any particular ill effects, but it is
> The PE count for the PV *is* updated. Strangely, after reboot (at least
> with lvm 1.0.3) the PE count for the PV does not include PEs used by
> snapshots. As soon as a single snapshot is created, removed, extended, or
> reduced, it becomes correct again. Again, I haven't noticed any particular
> ill effects.
> Following is a patch that solves the first problem (but not the second) for
> lvm 1.0.3. Looking at current CVS, I believe the problem still exists. The
> first portion of the patch adjusts vg's pe_allocated field in
> __extend_reduce_snapshot(). The second portion of the patch updates the
> snapshot's lv_allocated_snapshot_le field to be correct after a resize in
> lvm_do_lv_extend_reduce(). No user space changes are required.
> Dale J. Stephenson
> steph at snapserver.com
> --- linux/drivers/md/lvm.c.orig Mon Apr 29 08:50:41 2002
> +++ linux/drivers/md/lvm.c Mon Apr 29 12:41:29 2002
> @@ -2280,6 +2280,9 @@
> return -ENOMEM;
> + vg_ptr->pe_allocated -= old_lv->lv_allocated_snapshot_le;
> + vg_ptr->pe_allocated += new_lv->lv_allocated_le;
> return 0;
> @@ -2409,6 +2412,8 @@
> + old_lv->lv_allocated_snapshot_le =
> + new_lv->lv_allocated_le;
> old_lv->lv_remap_end = new_lv->lv_remap_end;
> old_lv->lv_block_exception = new_lv->lv_block_exception;
> old_lv->lv_snapshot_hash_table =
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> linux-lvm at sistina.com
> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
*** Software bugs are stupid.
Nevertheless it needs not so stupid people to solve them ***
Heinz Mauelshagen Sistina Software Inc.
Senior Consultant/Developer Am Sonnenhang 11
Mauelshagen at Sistina.com +49 2626 141200
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