[ 56/68] raid5: delayed stripe fix

[Greg Kroah-Hartman]

From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>

3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Shaohua Li <shli@xxxxxxxxxx>

commit fab363b5ff502d1b39ddcfec04271f5858d9f26e upstream.

There isn't locking setting STRIPE_DELAYED and STRIPE_PREREAD_ACTIVE bits, but
the two bits have relationship. A delayed stripe can be moved to hold list only
when preread active stripe count is below IO_THRESHOLD. If a stripe has both
the bits set, such stripe will be in delayed list and preread count not 0,
which will make such stripe never leave delayed list.

Signed-off-by: Shaohua Li <shli@xxxxxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/md/raid5.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -199,12 +199,14 @@ static void __release_stripe(raid5_conf_
 		BUG_ON(!list_empty(&sh->lru));
 		BUG_ON(atomic_read(&conf->active_stripes)==0);
 		if (test_bit(STRIPE_HANDLE, &sh->state)) {
-			if (test_bit(STRIPE_DELAYED, &sh->state))
+			if (test_bit(STRIPE_DELAYED, &sh->state) &&
+			    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 				list_add_tail(&sh->lru, &conf->delayed_list);
 			else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 				   sh->bm_seq - conf->seq_write > 0)
 				list_add_tail(&sh->lru, &conf->bitmap_list);
 			else {
+				clear_bit(STRIPE_DELAYED, &sh->state);
 				clear_bit(STRIPE_BIT_DELAY, &sh->state);
 				list_add_tail(&sh->lru, &conf->handle_list);
 			}


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