md/raid5-cache: stripe reclaim only counts valid stripes

shligit · shligit · commit e8fd52eec2cd · 2017-02-13T09:20:02.000-08:00
When log space is tight, we try to reclaim stripes from log head. There
are stripes which can't be reclaimed right now if some conditions are
met. We skip such stripes but accidentally count them, which might cause
no stripes are claimed. Fixing this by only counting valid stripes.

Cc: Song Liu &lt;songliubraving@fb.com&gt;
Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
@@ -1418,9 +1418,9 @@ static void r5c_do_reclaim(struct r5conf *conf)
 			    !test_bit(STRIPE_HANDLE, &sh->state) &&
 			    atomic_read(&sh->count) == 0) {
 				r5c_flush_stripe(conf, sh);
+				if (count++ >= R5C_RECLAIM_STRIPE_GROUP)
+					break;
 			}
-			if (count++ >= R5C_RECLAIM_STRIPE_GROUP)
-				break;
 		}
 		spin_unlock(&conf->device_lock);
 		spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);

Original file line number	Diff line number	Diff line change
`@@ -1418,9 +1418,9 @@ static void r5c_do_reclaim(struct r5conf *conf)`
`1418`	`1418`	`!test_bit(STRIPE_HANDLE, &sh->state) &&`
`1419`	`1419`	`atomic_read(&sh->count) == 0) {`
`1420`	`1420`	`r5c_flush_stripe(conf, sh);`
	`1421`	`+ if (count++ >= R5C_RECLAIM_STRIPE_GROUP)`
	`1422`	`+ break;`
`1421`	`1423`	`}`
`1422`		`- if (count++ >= R5C_RECLAIM_STRIPE_GROUP)`
`1423`		`- break;`
`1424`	`1424`	`}`
`1425`	`1425`	`spin_unlock(&conf->device_lock);`
`1426`	`1426`	`spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);`