[PATCH 09/14] block: always treat offline and read-only zones as dead

[Damien Le Moal <dlemoal@kernel.org>]

Since any write BIO targeting an offline or a read-only zone will fail,
there is no point in keeping zone write plugs for these zones.
So for any offline or read-only zone, the zone write plug should always
be treated as dead.

Do this by modifying disk_check_zone_wplug_dead() to always mark read-only
and offline zones as dead to force a removal of the zone write plug from
the disk hash table on BIO submission. blk_zone_wplug_prepare_bio() is
also modified to have the same checks to immediately fail a write BIO
targeting a read-only or offline zone. With these two changes, any newly
issued or unplugged write BIO targeting a read-only or offline zone is
immediately failed.

Finally, disk_zone_wplug_sync_state() is modified to add a call to
disk_mark_zone_wplug_dead() for the zone write plug of any read-only or
offline zone found during zone revalidation or a report zones.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 block/blk-zoned.c | 113 +++++++++++++++++++++++++---------------------
 1 file changed, 61 insertions(+), 52 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 1560b000fb08..069251171154 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -744,6 +744,53 @@ static inline void disk_put_zone_wplug(struct blk_zone_wplug *zwplug)
 		disk_free_zone_wplug(zwplug);
 }
 
+static inline void blk_zone_wplug_bio_io_error(struct blk_zone_wplug *zwplug,
+					       struct bio *bio)
+{
+	struct request_queue *q = zwplug->disk->queue;
+
+	bio_clear_flag(bio, BIO_ZONE_WRITE_PLUGGING);
+	bio_io_error(bio);
+	disk_put_zone_wplug(zwplug);
+	/* Drop the reference taken by disk_zone_wplug_add_bio(). */
+	blk_queue_exit(q);
+}
+
+/*
+ * Abort (fail) all plugged BIOs of a zone write plug.
+ */
+static void disk_zone_wplug_abort(struct blk_zone_wplug *zwplug)
+{
+	struct gendisk *disk = zwplug->disk;
+	struct bio *bio;
+
+	lockdep_assert_held(&zwplug->lock);
+
+	if (bio_list_empty(&zwplug->bio_list))
+		return;
+
+	pr_warn_ratelimited("%s: zone %u: Aborting plugged BIOs\n",
+			    zwplug->disk->disk_name, zwplug->zone_no);
+	while ((bio = bio_list_pop(&zwplug->bio_list)))
+		blk_zone_wplug_bio_io_error(zwplug, bio);
+
+	zwplug->flags &= ~BLK_ZONE_WPLUG_PLUGGED;
+
+	/*
+	 * If we are using the per disk zone write plugs worker thread, remove
+	 * the zone write plug from the work list and drop the reference we
+	 * took when the zone write plug was added to that list.
+	 */
+	if (blk_queue_zoned_qd1_writes(disk->queue)) {
+		spin_lock(&disk->zone_wplugs_list_lock);
+		if (!list_empty(&zwplug->entry)) {
+			list_del_init(&zwplug->entry);
+			disk_put_zone_wplug(zwplug);
+		}
+		spin_unlock(&disk->zone_wplugs_list_lock);
+	}
+}
+
 /*
  * Flag the zone write plug as dead and drop the initial reference we got when
  * the zone write plug was added to the hash table. The zone write plug will be
@@ -761,6 +808,12 @@ static void disk_mark_zone_wplug_dead(struct blk_zone_wplug *zwplug)
 
 static inline bool disk_check_zone_wplug_dead(struct blk_zone_wplug *zwplug)
 {
+	if (disk_zone_wplug_is_offline_or_readonly(zwplug)) {
+		disk_zone_wplug_abort(zwplug);
+		disk_mark_zone_wplug_dead(zwplug);
+		return true;
+	}
+
 	if (!(zwplug->flags & BLK_ZONE_WPLUG_DEAD))
 		return false;
 
@@ -844,53 +897,6 @@ static struct blk_zone_wplug *disk_get_or_alloc_zone_wplug(struct gendisk *disk,
 	return zwplug;
 }
 
-static inline void blk_zone_wplug_bio_io_error(struct blk_zone_wplug *zwplug,
-					       struct bio *bio)
-{
-	struct request_queue *q = zwplug->disk->queue;
-
-	bio_clear_flag(bio, BIO_ZONE_WRITE_PLUGGING);
-	bio_io_error(bio);
-	disk_put_zone_wplug(zwplug);
-	/* Drop the reference taken by disk_zone_wplug_add_bio(). */
-	blk_queue_exit(q);
-}
-
-/*
- * Abort (fail) all plugged BIOs of a zone write plug.
- */
-static void disk_zone_wplug_abort(struct blk_zone_wplug *zwplug)
-{
-	struct gendisk *disk = zwplug->disk;
-	struct bio *bio;
-
-	lockdep_assert_held(&zwplug->lock);
-
-	if (bio_list_empty(&zwplug->bio_list))
-		return;
-
-	pr_warn_ratelimited("%s: zone %u: Aborting plugged BIOs\n",
-			    zwplug->disk->disk_name, zwplug->zone_no);
-	while ((bio = bio_list_pop(&zwplug->bio_list)))
-		blk_zone_wplug_bio_io_error(zwplug, bio);
-
-	zwplug->flags &= ~BLK_ZONE_WPLUG_PLUGGED;
-
-	/*
-	 * If we are using the per disk zone write plugs worker thread, remove
-	 * the zone write plug from the work list and drop the reference we
-	 * took when the zone write plug was added to that list.
-	 */
-	if (blk_queue_zoned_qd1_writes(disk->queue)) {
-		spin_lock(&disk->zone_wplugs_list_lock);
-		if (!list_empty(&zwplug->entry)) {
-			list_del_init(&zwplug->entry);
-			disk_put_zone_wplug(zwplug);
-		}
-		spin_unlock(&disk->zone_wplugs_list_lock);
-	}
-}
-
 /*
  * Update a zone write plug condition based on the write pointer offset.
  */
@@ -967,8 +973,10 @@ static unsigned int disk_zone_wplug_sync_state(struct gendisk *disk,
 		spin_lock_irqsave(&zwplug->lock, flags);
 		if (zwplug->flags & BLK_ZONE_WPLUG_NEED_WP_UPDATE)
 			disk_zone_wplug_set_wp_offset(disk, zwplug, wp_offset);
-		if (disk_zone_cond_is_offline_or_readonly(zone->cond))
+		if (disk_zone_cond_is_offline_or_readonly(zone->cond)) {
 			zwplug->cond = zone->cond;
+			disk_mark_zone_wplug_dead(zwplug);
+		}
 		spin_unlock_irqrestore(&zwplug->lock, flags);
 		disk_put_zone_wplug(zwplug);
 	}
@@ -1521,11 +1529,12 @@ static bool blk_zone_wplug_prepare_bio(struct blk_zone_wplug *zwplug,
 		return false;
 
 	/*
-	 * Check that the user is not attempting to write to a full zone.
-	 * We know such BIO will fail, and that would potentially overflow our
-	 * write pointer offset beyond the end of the zone.
+	 * Check that the user is not attempting to write to a full, read-only
+	 * or offline zone. We know such BIOs will fail, so there is no point
+	 * in issuing them.
 	 */
-	if (disk_zone_wplug_is_full(disk, zwplug))
+	if (disk_zone_wplug_is_full(disk, zwplug) ||
+	    disk_zone_wplug_is_offline_or_readonly(zwplug))
 		return false;
 
 	if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
-- 
2.55.0