md/raid5: Ensure a batch member is not handled prematurely.
If a stripe is a member of a batch, but not the head, it must
not be handled separately from the rest of the batch.
'clear_batch_ready()' handles this requirement to some
extent but not completely. If a member is passed to handle_stripe()
a second time it returns '0' indicating the stripe can be handled,
which is wrong.
So add an extra test.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 42d0ea6..e587367 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4200,9 +4200,13 @@
static int clear_batch_ready(struct stripe_head *sh)
{
+ /* Return '1' if this is a member of batch, or
+ * '0' if it is a lone stripe or a head which can now be
+ * handled.
+ */
struct stripe_head *tmp;
if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
- return 0;
+ return (sh->batch_head && sh->batch_head != sh);
spin_lock(&sh->stripe_lock);
if (!sh->batch_head) {
spin_unlock(&sh->stripe_lock);