From: Mikulas Patocka We must zero the next chunk on disk *before* writing out the current chunk, not after. Otherwise if the machine crashes at the wrong time, the "end of metadata" marker may be missing. Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon Cc: stable@kernel.org --- drivers/md/dm-exception-store.c | 11 ++++++++--- 1 files changed, 8 insertions(+), 3 deletions(-) Index: linux-2.6.27/drivers/md/dm-exception-store.c =================================================================== --- linux-2.6.27.orig/drivers/md/dm-exception-store.c 2008-10-21 17:33:41.000000000 +0100 +++ linux-2.6.27/drivers/md/dm-exception-store.c 2008-10-21 17:33:42.000000000 +0100 @@ -611,17 +611,22 @@ static void persistent_commit(struct exc return; /* + * If we completely filled the current area, then wipe the next one. + */ + if ((ps->current_committed == ps->exceptions_per_area) && + zero_disk_area(ps, ps->current_area + 1)) + ps->valid = 0; + + /* * Commit exceptions to disk. */ - if (area_io(ps, WRITE)) + if (ps->valid && area_io(ps, WRITE)) ps->valid = 0; /* * Advance to the next area if this one is full. */ if (ps->current_committed == ps->exceptions_per_area) { - if (zero_disk_area(ps, ps->current_area + 1)) - ps->valid = 0; ps->current_committed = 0; ps->current_area++; zero_memory_area(ps);