Re: using the raid6check report

[NeilBrown <neilb@suse.com>]

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On Mon, Jan 09 2017, Eyal Lebedinsky wrote:

>
> I am aware of that discussion and agree with the sentiment (fix in user space).

(I primarily provided for the information of others)

> What I miss is a message from md when a 'check' mismatch is found. Not having
> this means I have to run 'raid6check', then after looking at the situation
> run 'raid6check autorepair' in the small sections reported as bad. This is time
> consuming and risky.

Something like this?

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 69b0a169e43d..f19c38baf2b2 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2738,6 +2738,8 @@ static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
 			conf->mddev->resync_mismatches += STRIPE_SECTORS;
 			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
 				/* don't try to repair!! */
+				pr_debug("%s: \"check\" found inconsistency near sector %llu\n",
+					 md_name(conf->mddev), sh->sector);
 				set_bit(STRIPE_INSYNC, &sh->state);
 			else {
 				sh->check_state = check_state_compute_run;


I chose pr_debug() because I didn't want to flood the logs if there are
lots of inconsistencies.
You can selectively enable pr_debug() messages by writing to
/sys/kernel/debug/dynamic_debug/control
providing you have dynamic debugging compiled in.

Maybe use pr_info_ratelimited() instead??

NeilBrown

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