From: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Date: Fri, 19 Jun 2020 16:49:56 +0900
Subject: [PATCH] dm zoned: Fix reclaim zone selection
Git-commit: f2cd9a5e85dc25e10f6318bc6fbcb7dcff262561
Patch-mainline: v5.8-rc3
References: bsc#1175995,jsc#SLE-15608
When dm zoned has multiple devices, random zones are never selected for
reclaim if all reserved sequential write zones are in use and no
sequential write required zones can be selected for reclaim. This can
lead to deadlocks as selecting a cache zone allows reclaiming a
sequential zone, ensuring forward progress.
Fix this by always defaulting to selecting a random zone when no
sequential write required zone can be selected.
[Damien: fix commit message]
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/md/dm-zoned-metadata.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
index b40e643ddf73..5cf6f5f552e0 100644
--- a/drivers/md/dm-zoned-metadata.c
+++ b/drivers/md/dm-zoned-metadata.c
@@ -2026,7 +2026,7 @@ static struct dm_zone *dmz_get_seq_zone_for_reclaim(struct dmz_metadata *zmd,
struct dm_zone *dmz_get_zone_for_reclaim(struct dmz_metadata *zmd,
unsigned int dev_idx, bool idle)
{
- struct dm_zone *zone;
+ struct dm_zone *zone = NULL;
/*
* Search for a zone candidate to reclaim: 2 cases are possible.
@@ -2039,7 +2039,7 @@ struct dm_zone *dmz_get_zone_for_reclaim(struct dmz_metadata *zmd,
dmz_lock_map(zmd);
if (list_empty(&zmd->reserved_seq_zones_list))
zone = dmz_get_seq_zone_for_reclaim(zmd, dev_idx);
- else
+ if (!zone)
zone = dmz_get_rnd_zone_for_reclaim(zmd, dev_idx, idle);
dmz_unlock_map(zmd);
--
2.16.4