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md: fix raid5 'repair' operations 

commit bd2ab67030 "md: close a livelock window
in handle_parity_checks5" introduced a bug in handling 'repair' operations.
After a repair operation completes we clear the state bits tracking this
operation.  However, they are cleared too early and this results in the code
deciding to re-run the parity check operation.  Since we have done the repair
in memory the second check does not find a mismatch and thus does not do a
writeback.

Test results:
$ echo repair > /sys/block/md0/md/sync_action
$ cat /sys/block/md0/md/mismatch_cnt
51072
$ echo repair > /sys/block/md0/md/sync_action
$ cat /sys/block/md0/md/mismatch_cnt
0

(also fix incorrect indentation)

Cc: <stable@kernel.org>
Tested-by: George Spelvin <linux@horizon.com>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Dan Williams 2008-05-12 14:02:12 -07:00 committed by Linus Torvalds
parent 3f275ea308
commit c8894419ac
1 changed files with 13 additions and 12 deletions
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25
drivers/md/raid5.c
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@ -2369,8 +2369,8 @@ static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
/* 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);
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,
@ -2400,16 +2400,6 @@ static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
canceled_check = 1; /* STRIPE_INSYNC is not set */
}
/* 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);
}
/* start a new check operation if there are no failures, the stripe is
* not insync, and a repair is not in flight
*/
@ -2424,6 +2414,17 @@ static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
}
}
/* 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 a failure occurred while the check operation
* was in flight we need to cycle this stripe through handle_stripe