From 7acedc5b98a2fcff64f00c21110aae7d3ac2f7df Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Tue, 21 Oct 2008 17:44:56 +0100 Subject: [PATCH] dm exception store: fix misordered writes 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 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c index fe6cef8df203..6179bf70f98a 100644 --- a/drivers/md/dm-exception-store.c +++ b/drivers/md/dm-exception-store.c @@ -610,18 +610,23 @@ static void persistent_commit(struct exception_store *store, (ps->current_committed != ps->exceptions_per_area)) 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);