If a failure is detected after a parity check operation has been
initiated, but before it completes handle_parity_checks5 will never
quiesce operations on the stripe.

Explicitly handle this case by "canceling" the parity check, i.e. clear
the STRIPE_OP_CHECK flags and queue the stripe on the handle list again
to refresh any non-uptodate blocks.

Kernel versions >= 2.6.23 are susceptible.

Cc: stable@kernel.org
Cc: NeilBrown
Signed-off-by: Dan Williams
---

drivers/md/raid5.c | 51 +++++++++++++++++++++++++++++----------------------
1 files changed, 29 insertions(+), 22 deletions(-)


diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e43e27a..476142f 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2363,25 +2363,15 @@ static void handle_issuing_new_write_requests6(raid5_conf_t *conf,
static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
struct stripe_head_state *s, int disks)
{
+ int canceled_check = 0;
+
set_bit(STRIPE_HANDLE, &sh->state);
- /* Take one of the following actions:
- * 1/ start a check parity operation if (uptodate == disks)
- * 2/ finish a check parity operation and act on the result
- * 3/ skip to the writeback section if we previously
- * initiated a recovery operation
- */
- if (s->failed == 0 &&
- !test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
- if (!test_and_set_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
- BUG_ON(s->uptodate != disks);
- clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
- sh->ops.count++;
- s->uptodate--;
- } else if (
- test_and_clear_bit(STRIPE_OP_CHECK, &sh->ops.complete)) {
- clear_bit(STRIPE_OP_CHECK, &sh->ops.ack);
- clear_bit(STRIPE_OP_CHECK, &sh->ops.pending);

+ /* complete a check operation */
+ if (test_and_clear_bit(STRIPE_OP_CHECK, &sh->ops.complete)) {
+ clear_bit(STRIPE_OP_CHECK, &sh->ops.ack);
+ clear_bit(STRIPE_OP_CHECK, &sh->ops.pending);
+ if (s->failed == 0) {
if (sh->ops.zero_sum_result == 0)
/* parity is correct (on disc,
* not in buffer any more)
@@ -2406,7 +2396,8 @@ static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
s->uptodate++;
}
}
- }
+ } else
+ canceled_check = 1; /* STRIPE_INSYNC is not set */
}

/* check if we can clear a parity disk reconstruct */
@@ -2419,12 +2410,28 @@ static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
}

+ /* start a new check operation if there are no failures, the stripe is
+ * not insync, and a repair is not in flight
+ */
+ if (s->failed == 0 &&
+ !test_bit(STRIPE_INSYNC, &sh->state) &&
+ !test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
+ if (!test_and_set_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
+ BUG_ON(s->uptodate != disks);
+ clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
+ sh->ops.count++;
+ s->uptodate--;
+ }
+ }
+
/* Wait for check parity and compute block operations to complete
- * before write-back
+ * before write-back. If a failure occurred while the check operation
+ * was in flight we need to cycle this stripe through handle_stripe
+ * since the parity block may not be uptodate
*/
- if (!test_bit(STRIPE_INSYNC, &sh->state) &&
- !test_bit(STRIPE_OP_CHECK, &sh->ops.pending) &&
- !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) {
+ if (!canceled_check && !test_bit(STRIPE_INSYNC, &sh->state) &&
+ !test_bit(STRIPE_OP_CHECK, &sh->ops.pending) &&
+ !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) {
struct r5dev *dev;
/* either failed parity check, or recovery is happening */
if (s->failed == 0)

--
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