dm zoned: improve error handling in reclaim

There are several places in reclaim code where errors are not
propagated to the main function, dmz_reclaim(). This function
is responsible for unlocking zones that might be still locked
at the end of any failed reclaim iterations. As the result,
some device zones may be left permanently locked for reclaim,
degrading target's capability to reclaim zones.

This patch fixes these issues as follows -

Make sure that dmz_reclaim_buf(), dmz_reclaim_seq_data() and
dmz_reclaim_rnd_data() return error codes to the caller.

dmz_reclaim() function is renamed to dmz_do_reclaim() to avoid
clashing with "struct dmz_reclaim" and is modified to return the
error to the caller.

dmz_get_zone_for_reclaim() now returns an error instead of NULL
pointer and reclaim code checks for that error.

Error logging/debug messages are added where necessary.

Fixes: 3b1a94c88b79 ("dm zoned: drive-managed zoned block device target")
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
index 8545dcee9fd0..935d9be5af39 100644
--- a/drivers/md/dm-zoned-metadata.c
+++ b/drivers/md/dm-zoned-metadata.c
@@ -1542,7 +1542,7 @@ static struct dm_zone *dmz_get_rnd_zone_for_reclaim(struct dmz_metadata *zmd)
 	struct dm_zone *zone;
 
 	if (list_empty(&zmd->map_rnd_list))
-		return NULL;
+		return ERR_PTR(-EBUSY);
 
 	list_for_each_entry(zone, &zmd->map_rnd_list, link) {
 		if (dmz_is_buf(zone))
@@ -1553,7 +1553,7 @@ static struct dm_zone *dmz_get_rnd_zone_for_reclaim(struct dmz_metadata *zmd)
 			return dzone;
 	}
 
-	return NULL;
+	return ERR_PTR(-EBUSY);
 }
 
 /*