Dale, thanks for finding this bug. Obviously people don't resize populated snapshots very often or we'ld seen this one much earlier ;) Your fix is in LVM_BRANCH_1-0 for everybody to test. We plan to revert CVS and will announce the change seperately. Regards, Heinz -- The LVM Guy -- On Wed, Feb 05, 2003 at 01:07:01PM -0500, Dale J. Stephenson wrote: > I've discovered a problem with using lvreduce/lvextend on LVM. The > resized snapshot will have a new exception table and hash table > allocated for it. But lvm_hash_link will be called for these in a loop > that depends on the lv_remap_ptr counter passed down from userspace -- > which will always be zero. The result is that existing COW on the > snapshot are ignored, and the contents of the snapshot can magically > change to reflect the current state of the source volume. Reboot (or > deactivating and reactivating the volume group) should solve the > problem, although it may be possible in the meantime to store a new COW > exception for a chunk that already has one. > > The fix is simple: > > --- lvm.c.orig Tue Feb 4 18:36:58 2003 > +++ lvm.c Tue Feb 4 18:43:26 2003 > @@ -2792,7 +2792,7 @@ > old_lv->lv_snapshot_hash_mask = > new_lv->lv_snapshot_hash_mask; > > - for (e = 0; e < new_lv->lv_remap_ptr; e++) > + for (e = 0; e < old_lv->lv_remap_ptr; e++) > lvm_hash_link(new_lv->lv_block_exception + e, > new_lv->lv_block_exception[e]. > rdev_org, > > As a side note, why not revert the main LVM cvs tree back to LVM 1.0.6? > 1.1 is dead. > > Dale J. Stephenson > dalestephenson@mac.com > > > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ *** 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 56242 Marienrachdorf Germany Mauelshagen@Sistina.com +49 2626 141200 FAX 924446 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
