lkml.org 
[lkml]   [2006]   [Apr]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
Subject[PATCH 005 of 5] md: Fix 'rdev->nr_pending' count when retrying barrier requests.

When retrying a failed BIO_RW_BARRIER request, we need to
keep the reference in ->nr_pending over the whole retry.
Currently, we only hold the reference if the failed request is
the *last* one to finish - which is silly, because it would normally
be the first to finish.

So move the rdev_dec_pending call up into the didn't-fail branch.
As the rdev isn't used in the later code, calling rdev_dec_pending
earlier doesn't hurt.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
./drivers/md/raid1.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff ./drivers/md/raid1.c~current~ ./drivers/md/raid1.c
--- ./drivers/md/raid1.c~current~ 2006-04-28 12:17:40.000000000 +1000
+++ ./drivers/md/raid1.c 2006-04-28 12:17:58.000000000 +1000
@@ -319,6 +319,7 @@ static int raid1_end_write_request(struc
set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
set_bit(R1BIO_BarrierRetry, &r1_bio->state);
r1_bio->mddev->barriers_work = 0;
+ /* Don't rdev_dec_pending in this branch - keep it for the retry */
} else {
/*
* this branch is our 'one mirror IO has finished' event handler:
@@ -365,6 +366,7 @@ static int raid1_end_write_request(struc
}
}
}
+ rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
}
/*
*
@@ -374,11 +376,9 @@ static int raid1_end_write_request(struc
if (atomic_dec_and_test(&r1_bio->remaining)) {
if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
reschedule_retry(r1_bio);
- /* Don't dec_pending yet, we want to hold
- * the reference over the retry
- */
goto out;
}
+ /* it really is the end of this request */
if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
/* free extra copy of the data pages */
int i = bio->bi_vcnt;
@@ -393,8 +393,6 @@ static int raid1_end_write_request(struc
md_write_end(r1_bio->mddev);
raid_end_bio_io(r1_bio);
}
-
- rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
out:
if (to_put)
bio_put(to_put);
@@ -1414,6 +1412,7 @@ static void raid1d(mddev_t *mddev)
* Better resubmit without the barrier.
* We know which devices to resubmit for, because
* all others have had their bios[] entry cleared.
+ * We already have a nr_pending reference on these rdevs.
*/
int i;
clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2006-04-28 04:55    [from the cache]
©2003-2011 Jasper Spaans