[PATCH 0/1] Fix raid1 resync getting stuck

[PATCH 0/1] Fix raid1 resync getting stuck

[Jes.Sorensen]

From: Jes Sorensen <Jes.Sorensen@redhat.com>

Neil,

This patch seems to do the job for us. Nate ran testing with > 500
iterations which would normally fail in less than 10.

I tried changing MaxSector to ((~(sector_t)0) >> 1) as you suggested,
but that made the raid5 code go explosive. This on the other hand
seems to do the trick.

Cheers,
Jes


Jes Sorensen (1):
  md/raid1: Avoid raid1 resync getting stuck

 drivers/md/raid1.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

-- 
2.4.3

[PATCH 1/1] md/raid1: Avoid raid1 resync getting stuck

[Jes.Sorensen]

From: Jes Sorensen <Jes.Sorensen@redhat.com>

close_sync() needs to set conf->next_resync to a large, but safe value
below MaxSector and use it to determine whether or not to set
start_next_window in wait_barrier()

Solution suggested by Neil Brown.

Reported-by: Nate Dailey <nate.dailey@stratus.com>
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
---
 drivers/md/raid1.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 4517f06..763a0a8 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -881,8 +881,7 @@ static sector_t wait_barrier(struct r1conf *conf, struct bio *bio)
 	}
 
 	if (bio && bio_data_dir(bio) == WRITE) {
-		if (bio->bi_iter.bi_sector >=
-		    conf->mddev->curr_resync_completed) {
+		if (bio->bi_iter.bi_sector >= conf->next_resync) {
 			if (conf->start_next_window == MaxSector)
 				conf->start_next_window =
 					conf->next_resync +
@@ -1516,7 +1515,7 @@ static void close_sync(struct r1conf *conf)
 	conf->r1buf_pool = NULL;
 
 	spin_lock_irq(&conf->resync_lock);
-	conf->next_resync = 0;
+	conf->next_resync = MaxSector - 2 * NEXT_NORMALIO_DISTANCE;
 	conf->start_next_window = MaxSector;
 	conf->current_window_requests +=
 		conf->next_window_requests;
-- 
2.4.3

Re: [PATCH 1/1] md/raid1: Avoid raid1 resync getting stuck

[Neil Brown]

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Jes.Sorensen@redhat.com writes:

> From: Jes Sorensen <Jes.Sorensen@redhat.com>
>
> close_sync() needs to set conf->next_resync to a large, but safe value
> below MaxSector and use it to determine whether or not to set
> start_next_window in wait_barrier()
>
> Solution suggested by Neil Brown.
>
> Reported-by: Nate Dailey <nate.dailey@stratus.com>
> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> ---
>  drivers/md/raid1.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 4517f06..763a0a8 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -881,8 +881,7 @@ static sector_t wait_barrier(struct r1conf *conf, struct bio *bio)
>  	}
>  
>  	if (bio && bio_data_dir(bio) == WRITE) {
> -		if (bio->bi_iter.bi_sector >=
> -		    conf->mddev->curr_resync_completed) {
> +		if (bio->bi_iter.bi_sector >= conf->next_resync) {
>  			if (conf->start_next_window == MaxSector)
>  				conf->start_next_window =
>  					conf->next_resync +
> @@ -1516,7 +1515,7 @@ static void close_sync(struct r1conf *conf)
>  	conf->r1buf_pool = NULL;
>  
>  	spin_lock_irq(&conf->resync_lock);
> -	conf->next_resync = 0;
> +	conf->next_resync = MaxSector - 2 * NEXT_NORMALIO_DISTANCE;
>  	conf->start_next_window = MaxSector;
>  	conf->current_window_requests +=
>  		conf->next_window_requests;
> -- 
> 2.4.3
Applied, thanks.

NeilBrown

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