From: Dan Williams <dan.j.williams@xxxxxxxxx>
handle_stripe sets STRIPE_OP_CHECK to request a check operation in
raid5_run_ops. If raid5_run_ops is able to perform the check with a
dma engine the parity will be preserved and not re-read from disk.
Check operations re-use the compute block facility to repair the parity.
However since repairing the parity implies a write-back to disk the
STRIPE_OP_MOD_REPAIR_PD flag is added to distinguish it from other compute
block operations.
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/md/raid5.c | 81 ++++++++++++++++++++++++++++++++++++++++------------
1 files changed, 62 insertions(+), 19 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 8510183..1764fbb 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2465,32 +2465,75 @@ #endif
locked += handle_write_operations5(sh, rcw, 0);
}
- /* maybe we need to check and possibly fix the parity for this stripe
- * Any reads will already have been scheduled, so we just see if enough data
- * is available
+ /* 1/ Maybe we need to check and possibly fix the parity for this stripe.
+ * Any reads will already have been scheduled, so we just see if enough data
+ * is available.
+ * 2/ Hold off parity checks while parity dependent operations are in flight
+ * (conflicting writes are protected by the 'locked' variable)
*/
- if (syncing && locked == 0 &&
- !test_bit(STRIPE_INSYNC, &sh->state)) {
+ if ((syncing && locked == 0 && !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
+ !test_bit(STRIPE_INSYNC, &sh->state)) ||
+ test_bit(STRIPE_OP_CHECK, &sh->ops.pending) ||
+ test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
+
set_bit(STRIPE_HANDLE, &sh->state);
- if (failed == 0) {
- BUG_ON(uptodate != disks);
- compute_parity5(sh, CHECK_PARITY);
- uptodate--;
- if (page_is_zero(sh->dev[sh->pd_idx].page)) {
- /* parity is correct (on disc, not in buffer any more) */
- set_bit(STRIPE_INSYNC, &sh->state);
- } else {
- conf->mddev->resync_mismatches += STRIPE_SECTORS;
- if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
- /* don't try to repair!! */
+ /* 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 (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(uptodate != disks);
+ clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
+ sh->ops.count++;
+ 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);
+
+ if (sh->ops.zero_sum_result == 0)
+ /* parity is correct (on disc, not in buffer any more) */
set_bit(STRIPE_INSYNC, &sh->state);
else {
- compute_block(sh, sh->pd_idx);
- uptodate++;
+ conf->mddev->resync_mismatches += STRIPE_SECTORS;
+ if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
+ /* don't try to repair!! */
+ set_bit(STRIPE_INSYNC, &sh->state);
+ else {
+ BUG_ON(test_and_set_bit(
+ STRIPE_OP_COMPUTE_BLK,
+ &sh->ops.pending));
+ set_bit(STRIPE_OP_MOD_REPAIR_PD,
+ &sh->ops.pending);
+ BUG_ON(test_and_set_bit(R5_Wantcompute,
+ &sh->dev[sh->pd_idx].flags));
+ sh->ops.target = sh->pd_idx;
+ sh->ops.count++;
+ uptodate++;
+ }
}
}
}
- if (!test_bit(STRIPE_INSYNC, &sh->state)) {
+
+ /* check if we can clear a parity disk reconstruct */
+ if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete) &&
+ test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
+
+ clear_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending);
+ clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
+ clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
+ clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
+ }
+
+ /* Wait for check parity and compute block operations to complete
+ * before write-back
+ */
+ if (!test_bit(STRIPE_INSYNC, &sh->state) &&
+ !test_bit(STRIPE_OP_CHECK, &sh->ops.pending) &&
+ !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) {
+
/* either failed parity check, or recovery is happening */
if (failed==0)
failed_num = sh->pd_idx;
-
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