dm: introduce zone append emulation

For zoned targets that cannot support zone append operations, implement
an emulation using regular write operations. If the original BIO
submitted by the user is a zone append operation, change its clone into
a regular write operation directed at the target zone write pointer
position.

To do so, an array of write pointer offsets (write pointer position
relative to the start of a zone) is added to struct mapped_device. All
operations that modify a sequential zone write pointer (writes, zone
reset, zone finish and zone append) are intersepted in __map_bio() and
processed using the new functions dm_zone_map_bio().

Detection of the target ability to natively support zone append
operations is done from dm_table_set_restrictions() by calling the
function dm_set_zones_restrictions(). A target that does not support
zone append operation, either by explicitly declaring it using the new
struct dm_target field zone_append_not_supported, or because the device
table contains a non-zoned device, has its mapped device marked with the
new flag DMF_ZONE_APPEND_EMULATED. The helper function
dm_emulate_zone_append() is introduced to test a mapped device for this
new flag.

Atomicity of the zones write pointer tracking and updates is done using
a zone write locking mechanism based on a bitmap. This is similar to
the block layer method but based on BIOs rather than struct request.
A zone write lock is taken in dm_zone_map_bio() for any clone BIO with
an operation type that changes the BIO target zone write pointer
position. The zone write lock is released if the clone BIO is failed
before submission or when dm_zone_endio() is called when the clone BIO
completes.

The zone write lock bitmap of the mapped device, together with a bitmap
indicating zone types (conv_zones_bitmap) and the write pointer offset
array (zwp_offset) are allocated and initialized with a full device zone
report in dm_set_zones_restrictions() using the function
dm_revalidate_zones().

For failed operations that may have modified a zone write pointer, the
zone write pointer offset is marked as invalid in dm_zone_endio().
Zones with an invalid write pointer offset are checked and the write
pointer updated using an internal report zone operation when the
faulty zone is accessed again by the user.

All functions added for this emulation have a minimal overhead for
zoned targets natively supporting zone append operations. Regular
device targets are also not affected. The added code also does not
impact builds with CONFIG_BLK_DEV_ZONED disabled by stubbing out all
dm zone related functions.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-core.h

@@ -114,6 +114,11 @@ struct mapped_device {
 	bool init_tio_pdu:1;
 
 	struct srcu_struct io_barrier;
+
+#ifdef CONFIG_BLK_DEV_ZONED
+	unsigned int nr_zones;
+	unsigned int *zwp_offset;
+#endif
 };
 
 /*
@@ -128,6 +133,7 @@ struct mapped_device {
 #define DMF_DEFERRED_REMOVE 6
 #define DMF_SUSPENDED_INTERNALLY 7
 #define DMF_POST_SUSPENDING 8
+#define DMF_EMULATE_ZONE_APPEND 9
 
 void disable_discard(struct mapped_device *md);
 void disable_write_same(struct mapped_device *md);
@@ -143,6 +149,13 @@ static inline struct dm_stats *dm_get_stats(struct mapped_device *md)
 	return &md->stats;
 }
 
+static inline bool dm_emulate_zone_append(struct mapped_device *md)
+{
+	if (blk_queue_is_zoned(md->queue))
+		return test_bit(DMF_EMULATE_ZONE_APPEND, &md->flags);
+	return false;
+}
+
 #define DM_TABLE_MAX_DEPTH 16
 
 struct dm_table {

drivers/md/dm-table.c

@@ -1981,11 +1981,12 @@ static int device_requires_stable_pages(struct dm_target *ti,
 	return blk_queue_stable_writes(q);
 }
 
-void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
+int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 			      struct queue_limits *limits)
 {
 	bool wc = false, fua = false;
 	int page_size = PAGE_SIZE;
+	int r;
 
 	/*
 	 * Copy table's limits to the DM device's request_queue
@@ -2064,12 +2065,20 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	    dm_table_any_dev_attr(t, device_is_not_random, NULL))
 		blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, q);
 
-	/* For a zoned target, setup the zones related queue attributes */
-	if (blk_queue_is_zoned(q))
-		dm_set_zones_restrictions(t, q);
+	/*
+	 * For a zoned target, setup the zones related queue attributes
+	 * and resources necessary for zone append emulation if necessary.
+	 */
+	if (blk_queue_is_zoned(q)) {
+		r = dm_set_zones_restrictions(t, q);
+		if (r)
+			return r;
+	}
 
 	dm_update_keyslot_manager(q, t);
 	blk_queue_update_readahead(q);
+
+	return 0;
 }
 
 unsigned int dm_table_get_num_targets(struct dm_table *t)

drivers/md/dm-zone.c

@@ -4,55 +4,72 @@
  */
 
 #include <linux/blkdev.h>
+#include <linux/mm.h>
+#include <linux/sched/mm.h>
+#include <linux/slab.h>
 
 #include "dm-core.h"
 
+#define DM_MSG_PREFIX "zone"
+
+#define DM_ZONE_INVALID_WP_OFST		UINT_MAX
+
 /*
- * User facing dm device block device report zone operation. This calls the
- * report_zones operation for each target of a device table. This operation is
- * generally implemented by targets using dm_report_zones().
+ * For internal zone reports bypassing the top BIO submission path.
  */
-int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
-			unsigned int nr_zones, report_zones_cb cb, void *data)
+static int dm_blk_do_report_zones(struct mapped_device *md, struct dm_table *t,
+				  sector_t sector, unsigned int nr_zones,
+				  report_zones_cb cb, void *data)
 {
-	struct mapped_device *md = disk->private_data;
-	struct dm_table *map;
-	int srcu_idx, ret;
+	struct gendisk *disk = md->disk;
+	int ret;
 	struct dm_report_zones_args args = {
 		.next_sector = sector,
 		.orig_data = data,
 		.orig_cb = cb,
 	};
 
-	if (dm_suspended_md(md))
-		return -EAGAIN;
-
-	map = dm_get_live_table(md, &srcu_idx);
-	if (!map) {
-		ret = -EIO;
-		goto out;
-	}
-
 	do {
 		struct dm_target *tgt;
 
-		tgt = dm_table_find_target(map, args.next_sector);
-		if (WARN_ON_ONCE(!tgt->type->report_zones)) {
-			ret = -EIO;
-			goto out;
-		}
+		tgt = dm_table_find_target(t, args.next_sector);
+		if (WARN_ON_ONCE(!tgt->type->report_zones))
+			return -EIO;
 
 		args.tgt = tgt;
 		ret = tgt->type->report_zones(tgt, &args,
 					      nr_zones - args.zone_idx);
 		if (ret < 0)
-			goto out;
+			return ret;
 	} while (args.zone_idx < nr_zones &&
 		 args.next_sector < get_capacity(disk));
 
-	ret = args.zone_idx;
-out:
+	return args.zone_idx;
+}
+
+/*
+ * User facing dm device block device report zone operation. This calls the
+ * report_zones operation for each target of a device table. This operation is
+ * generally implemented by targets using dm_report_zones().
+ */
+int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
+			unsigned int nr_zones, report_zones_cb cb, void *data)
+{
+	struct mapped_device *md = disk->private_data;
+	struct dm_table *map;
+	int srcu_idx, ret;
+
+	if (dm_suspended_md(md))
+		return -EAGAIN;
+
+	map = dm_get_live_table(md, &srcu_idx);
+	if (!map)
+		return -EIO;
+
+	ret = dm_blk_do_report_zones(md, map, sector, nr_zones, cb, data);
+
 	dm_put_live_table(md, srcu_idx);
+
 	return ret;
 }
 
@@ -121,16 +138,517 @@ bool dm_is_zone_write(struct mapped_device *md, struct bio *bio)
 	}
 }
 
-void dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q)
+void dm_cleanup_zoned_dev(struct mapped_device *md)
 {
-	if (!blk_queue_is_zoned(q))
-		return;
+	struct request_queue *q = md->queue;
+
+	if (q) {
+		kfree(q->conv_zones_bitmap);
+		q->conv_zones_bitmap = NULL;
+		kfree(q->seq_zones_wlock);
+		q->seq_zones_wlock = NULL;
+	}
+
+	kvfree(md->zwp_offset);
+	md->zwp_offset = NULL;
+	md->nr_zones = 0;
+}
+
+static unsigned int dm_get_zone_wp_offset(struct blk_zone *zone)
+{
+	switch (zone->cond) {
+	case BLK_ZONE_COND_IMP_OPEN:
+	case BLK_ZONE_COND_EXP_OPEN:
+	case BLK_ZONE_COND_CLOSED:
+		return zone->wp - zone->start;
+	case BLK_ZONE_COND_FULL:
+		return zone->len;
+	case BLK_ZONE_COND_EMPTY:
+	case BLK_ZONE_COND_NOT_WP:
+	case BLK_ZONE_COND_OFFLINE:
+	case BLK_ZONE_COND_READONLY:
+	default:
+		/*
+		 * Conventional, offline and read-only zones do not have a valid
+		 * write pointer. Use 0 as for an empty zone.
+		 */
+		return 0;
+	}
+}
+
+static int dm_zone_revalidate_cb(struct blk_zone *zone, unsigned int idx,
+				 void *data)
+{
+	struct mapped_device *md = data;
+	struct request_queue *q = md->queue;
+
+	switch (zone->type) {
+	case BLK_ZONE_TYPE_CONVENTIONAL:
+		if (!q->conv_zones_bitmap) {
+			q->conv_zones_bitmap =
+				kcalloc(BITS_TO_LONGS(q->nr_zones),
+					sizeof(unsigned long), GFP_NOIO);
+			if (!q->conv_zones_bitmap)
+				return -ENOMEM;
+		}
+		set_bit(idx, q->conv_zones_bitmap);
+		break;
+	case BLK_ZONE_TYPE_SEQWRITE_REQ:
+	case BLK_ZONE_TYPE_SEQWRITE_PREF:
+		if (!q->seq_zones_wlock) {
+			q->seq_zones_wlock =
+				kcalloc(BITS_TO_LONGS(q->nr_zones),
+					sizeof(unsigned long), GFP_NOIO);
+			if (!q->seq_zones_wlock)
+				return -ENOMEM;
+		}
+		if (!md->zwp_offset) {
+			md->zwp_offset =
+				kvcalloc(q->nr_zones, sizeof(unsigned int),
+					 GFP_NOIO);
+			if (!md->zwp_offset)
+				return -ENOMEM;
+		}
+		md->zwp_offset[idx] = dm_get_zone_wp_offset(zone);
+
+		break;
+	default:
+		DMERR("Invalid zone type 0x%x at sectors %llu",
+		      (int)zone->type, zone->start);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+/*
+ * Revalidate the zones of a mapped device to initialize resource necessary
+ * for zone append emulation. Note that we cannot simply use the block layer
+ * blk_revalidate_disk_zones() function here as the mapped device is suspended
+ * (this is called from __bind() context).
+ */
+static int dm_revalidate_zones(struct mapped_device *md, struct dm_table *t)
+{
+	struct request_queue *q = md->queue;
+	int ret;
+
+	/*
+	 * Check if something changed. If yes, cleanup the current resources
+	 * and reallocate everything.
+	 */
+	if (!q->nr_zones || q->nr_zones != md->nr_zones)
+		dm_cleanup_zoned_dev(md);
+	if (md->nr_zones)
+		return 0;
+
+	/* Scan all zones to initialize everything */
+	ret = dm_blk_do_report_zones(md, t, 0, q->nr_zones,
+				     dm_zone_revalidate_cb, md);
+	if (ret < 0)
+		goto err;
+	if (ret != q->nr_zones) {
+		ret = -EIO;
+		goto err;
+	}
+
+	md->nr_zones = q->nr_zones;
+
+	return 0;
+
+err:
+	DMERR("Revalidate zones failed %d", ret);
+	dm_cleanup_zoned_dev(md);
+	return ret;
+}
+
+static int device_not_zone_append_capable(struct dm_target *ti,
+					  struct dm_dev *dev, sector_t start,
+					  sector_t len, void *data)
+{
+	return !blk_queue_is_zoned(bdev_get_queue(dev->bdev));
+}
+
+static bool dm_table_supports_zone_append(struct dm_table *t)
+{
+	struct dm_target *ti;
+	unsigned int i;
+
+	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+		ti = dm_table_get_target(t, i);
+
+		if (ti->emulate_zone_append)
+			return false;
+
+		if (!ti->type->iterate_devices ||
+		    ti->type->iterate_devices(ti, device_not_zone_append_capable, NULL))
+			return false;
+	}
+
+	return true;
+}
+
+int dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q)
+{
+	struct mapped_device *md = t->md;
 
 	/*
 	 * For a zoned target, the number of zones should be updated for the
-	 * correct value to be exposed in sysfs queue/nr_zones. For a BIO based
-	 * target, this is all that is needed.
+	 * correct value to be exposed in sysfs queue/nr_zones.
 	 */
 	WARN_ON_ONCE(queue_is_mq(q));
-	q->nr_zones = blkdev_nr_zones(t->md->disk);
+	q->nr_zones = blkdev_nr_zones(md->disk);
+
+	/* Check if zone append is natively supported */
+	if (dm_table_supports_zone_append(t)) {
+		clear_bit(DMF_EMULATE_ZONE_APPEND, &md->flags);
+		dm_cleanup_zoned_dev(md);
+		return 0;
+	}
+
+	/*
+	 * Mark the mapped device as needing zone append emulation and
+	 * initialize the emulation resources once the capacity is set.
+	 */
+	set_bit(DMF_EMULATE_ZONE_APPEND, &md->flags);
+	if (!get_capacity(md->disk))
+		return 0;
+
+	return dm_revalidate_zones(md, t);
+}
+
+static int dm_update_zone_wp_offset_cb(struct blk_zone *zone, unsigned int idx,
+				       void *data)
+{
+	unsigned int *wp_offset = data;
+
+	*wp_offset = dm_get_zone_wp_offset(zone);
+
+	return 0;
+}
+
+static int dm_update_zone_wp_offset(struct mapped_device *md, unsigned int zno,
+				    unsigned int *wp_ofst)
+{
+	sector_t sector = zno * blk_queue_zone_sectors(md->queue);
+	unsigned int noio_flag;
+	struct dm_table *t;
+	int srcu_idx, ret;
+
+	t = dm_get_live_table(md, &srcu_idx);
+	if (!t)
+		return -EIO;
+
+	/*
+	 * Ensure that all memory allocations in this context are done as if
+	 * GFP_NOIO was specified.
+	 */
+	noio_flag = memalloc_noio_save();
+	ret = dm_blk_do_report_zones(md, t, sector, 1,
+				     dm_update_zone_wp_offset_cb, wp_ofst);
+	memalloc_noio_restore(noio_flag);
+
+	dm_put_live_table(md, srcu_idx);
+
+	if (ret != 1)
+		return -EIO;
+
+	return 0;
+}
+
+/*
+ * First phase of BIO mapping for targets with zone append emulation:
+ * check all BIO that change a zone writer pointer and change zone
+ * append operations into regular write operations.
+ */
+static bool dm_zone_map_bio_begin(struct mapped_device *md,
+				  struct bio *orig_bio, struct bio *clone)
+{
+	sector_t zsectors = blk_queue_zone_sectors(md->queue);
+	unsigned int zno = bio_zone_no(orig_bio);
+	unsigned int zwp_offset = READ_ONCE(md->zwp_offset[zno]);
+
+	/*
+	 * If the target zone is in an error state, recover by inspecting the
+	 * zone to get its current write pointer position. Note that since the
+	 * target zone is already locked, a BIO issuing context should never
+	 * see the zone write in the DM_ZONE_UPDATING_WP_OFST state.
+	 */
+	if (zwp_offset == DM_ZONE_INVALID_WP_OFST) {
+		if (dm_update_zone_wp_offset(md, zno, &zwp_offset))
+			return false;
+		WRITE_ONCE(md->zwp_offset[zno], zwp_offset);
+	}
+
+	switch (bio_op(orig_bio)) {
+	case REQ_OP_ZONE_RESET:
+	case REQ_OP_ZONE_FINISH:
+		return true;
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE_SAME:
+	case REQ_OP_WRITE:
+		/* Writes must be aligned to the zone write pointer */
+		if ((clone->bi_iter.bi_sector & (zsectors - 1)) != zwp_offset)
+			return false;
+		break;
+	case REQ_OP_ZONE_APPEND:
+		/*
+		 * Change zone append operations into a non-mergeable regular
+		 * writes directed at the current write pointer position of the
+		 * target zone.
+		 */
+		clone->bi_opf = REQ_OP_WRITE | REQ_NOMERGE |
+			(orig_bio->bi_opf & (~REQ_OP_MASK));
+		clone->bi_iter.bi_sector =
+			orig_bio->bi_iter.bi_sector + zwp_offset;
+		break;
+	default:
+		DMWARN_LIMIT("Invalid BIO operation");
+		return false;
+	}
+
+	/* Cannot write to a full zone */
+	if (zwp_offset >= zsectors)
+		return false;
+
+	return true;
+}
+
+/*
+ * Second phase of BIO mapping for targets with zone append emulation:
+ * update the zone write pointer offset array to account for the additional
+ * data written to a zone. Note that at this point, the remapped clone BIO
+ * may already have completed, so we do not touch it.
+ */
+static blk_status_t dm_zone_map_bio_end(struct mapped_device *md,
+					struct bio *orig_bio,
+					unsigned int nr_sectors)
+{
+	unsigned int zno = bio_zone_no(orig_bio);
+	unsigned int zwp_offset = READ_ONCE(md->zwp_offset[zno]);
+
+	/* The clone BIO may already have been completed and failed */
+	if (zwp_offset == DM_ZONE_INVALID_WP_OFST)
+		return BLK_STS_IOERR;
+
+	/* Update the zone wp offset */
+	switch (bio_op(orig_bio)) {
+	case REQ_OP_ZONE_RESET:
+		WRITE_ONCE(md->zwp_offset[zno], 0);
+		return BLK_STS_OK;
+	case REQ_OP_ZONE_FINISH:
+		WRITE_ONCE(md->zwp_offset[zno],
+			   blk_queue_zone_sectors(md->queue));
+		return BLK_STS_OK;
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE_SAME:
+	case REQ_OP_WRITE:
+		WRITE_ONCE(md->zwp_offset[zno], zwp_offset + nr_sectors);
+		return BLK_STS_OK;
+	case REQ_OP_ZONE_APPEND:
+		/*
+		 * Check that the target did not truncate the write operation
+		 * emulating a zone append.
+		 */
+		if (nr_sectors != bio_sectors(orig_bio)) {
+			DMWARN_LIMIT("Truncated write for zone append");
+			return BLK_STS_IOERR;
+		}
+		WRITE_ONCE(md->zwp_offset[zno], zwp_offset + nr_sectors);
+		return BLK_STS_OK;
+	default:
+		DMWARN_LIMIT("Invalid BIO operation");
+		return BLK_STS_IOERR;
+	}
+}
+
+static inline void dm_zone_lock(struct request_queue *q,
+				unsigned int zno, struct bio *clone)
+{
+	if (WARN_ON_ONCE(bio_flagged(clone, BIO_ZONE_WRITE_LOCKED)))
+		return;
+
+	wait_on_bit_lock_io(q->seq_zones_wlock, zno, TASK_UNINTERRUPTIBLE);
+	bio_set_flag(clone, BIO_ZONE_WRITE_LOCKED);
+}
+
+static inline void dm_zone_unlock(struct request_queue *q,
+				  unsigned int zno, struct bio *clone)
+{
+	if (!bio_flagged(clone, BIO_ZONE_WRITE_LOCKED))
+		return;
+
+	WARN_ON_ONCE(!test_bit(zno, q->seq_zones_wlock));
+	clear_bit_unlock(zno, q->seq_zones_wlock);
+	smp_mb__after_atomic();
+	wake_up_bit(q->seq_zones_wlock, zno);
+
+	bio_clear_flag(clone, BIO_ZONE_WRITE_LOCKED);
+}
+
+static bool dm_need_zone_wp_tracking(struct bio *orig_bio)
+{
+	/*
+	 * Special processing is not needed for operations that do not need the
+	 * zone write lock, that is, all operations that target conventional
+	 * zones and all operations that do not modify directly a sequential
+	 * zone write pointer.
+	 */
+	if (op_is_flush(orig_bio->bi_opf) && !bio_sectors(orig_bio))
+		return false;
+	switch (bio_op(orig_bio)) {
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE_SAME:
+	case REQ_OP_WRITE:
+	case REQ_OP_ZONE_RESET:
+	case REQ_OP_ZONE_FINISH:
+	case REQ_OP_ZONE_APPEND:
+		return bio_zone_is_seq(orig_bio);
+	default:
+		return false;
+	}
+}
+
+/*
+ * Special IO mapping for targets needing zone append emulation.
+ */
+int dm_zone_map_bio(struct dm_target_io *tio)
+{
+	struct dm_io *io = tio->io;
+	struct dm_target *ti = tio->ti;
+	struct mapped_device *md = io->md;
+	struct request_queue *q = md->queue;
+	struct bio *orig_bio = io->orig_bio;
+	struct bio *clone = &tio->clone;
+	unsigned int zno;
+	blk_status_t sts;
+	int r;
+
+	/*
+	 * IOs that do not change a zone write pointer do not need
+	 * any additional special processing.
+	 */
+	if (!dm_need_zone_wp_tracking(orig_bio))
+		return ti->type->map(ti, clone);
+
+	/* Lock the target zone */
+	zno = bio_zone_no(orig_bio);
+	dm_zone_lock(q, zno, clone);
+
+	/*
+	 * Check that the bio and the target zone write pointer offset are
+	 * both valid, and if the bio is a zone append, remap it to a write.
+	 */
+	if (!dm_zone_map_bio_begin(md, orig_bio, clone)) {
+		dm_zone_unlock(q, zno, clone);
+		return DM_MAPIO_KILL;
+	}
+
+	/*
+	 * The target map function may issue and complete the IO quickly.
+	 * Take an extra reference on the IO to make sure it does disappear
+	 * until we run dm_zone_map_bio_end().
+	 */
+	dm_io_inc_pending(io);
+
+	/* Let the target do its work */
+	r = ti->type->map(ti, clone);
+	switch (r) {
+	case DM_MAPIO_SUBMITTED:
+		/*
+		 * The target submitted the clone BIO. The target zone will
+		 * be unlocked on completion of the clone.
+		 */
+		sts = dm_zone_map_bio_end(md, orig_bio, *tio->len_ptr);
+		break;
+	case DM_MAPIO_REMAPPED:
+		/*
+		 * The target only remapped the clone BIO. In case of error,
+		 * unlock the target zone here as the clone will not be
+		 * submitted.
+		 */
+		sts = dm_zone_map_bio_end(md, orig_bio, *tio->len_ptr);
+		if (sts != BLK_STS_OK)
+			dm_zone_unlock(q, zno, clone);
+		break;
+	case DM_MAPIO_REQUEUE:
+	case DM_MAPIO_KILL:
+	default:
+		dm_zone_unlock(q, zno, clone);
+		sts = BLK_STS_IOERR;
+		break;
+	}
+
+	/* Drop the extra reference on the IO */
+	dm_io_dec_pending(io, sts);
+
+	if (sts != BLK_STS_OK)
+		return DM_MAPIO_KILL;
+
+	return r;
+}
+
+/*
+ * IO completion callback called from clone_endio().
+ */
+void dm_zone_endio(struct dm_io *io, struct bio *clone)
+{
+	struct mapped_device *md = io->md;
+	struct request_queue *q = md->queue;
+	struct bio *orig_bio = io->orig_bio;
+	unsigned int zwp_offset;
+	unsigned int zno;
+
+	/*
+	 * For targets that do not emulate zone append, we only need to
+	 * handle native zone-append bios.
+	 */
+	if (!dm_emulate_zone_append(md)) {
+		/*
+		 * Get the offset within the zone of the written sector
+		 * and add that to the original bio sector position.
+		 */
+		if (clone->bi_status == BLK_STS_OK &&
+		    bio_op(clone) == REQ_OP_ZONE_APPEND) {
+			sector_t mask = (sector_t)blk_queue_zone_sectors(q) - 1;
+
+			orig_bio->bi_iter.bi_sector +=
+				clone->bi_iter.bi_sector & mask;
+		}
+
+		return;
+	}
+
+	/*
+	 * For targets that do emulate zone append, if the clone BIO does not
+	 * own the target zone write lock, we have nothing to do.
+	 */
+	if (!bio_flagged(clone, BIO_ZONE_WRITE_LOCKED))
+		return;
+
+	zno = bio_zone_no(orig_bio);
+
+	if (clone->bi_status != BLK_STS_OK) {
+		/*
+		 * BIOs that modify a zone write pointer may leave the zone
+		 * in an unknown state in case of failure (e.g. the write
+		 * pointer was only partially advanced). In this case, set
+		 * the target zone write pointer as invalid unless it is
+		 * already being updated.
+		 */
+		WRITE_ONCE(md->zwp_offset[zno], DM_ZONE_INVALID_WP_OFST);
+	} else if (bio_op(orig_bio) == REQ_OP_ZONE_APPEND) {
+		/*
+		 * Get the written sector for zone append operation that were
+		 * emulated using regular write operations.
+		 */
+		zwp_offset = READ_ONCE(md->zwp_offset[zno]);
+		if (WARN_ON_ONCE(zwp_offset < bio_sectors(orig_bio)))
+			WRITE_ONCE(md->zwp_offset[zno],
+				   DM_ZONE_INVALID_WP_OFST);
+		else
+			orig_bio->bi_iter.bi_sector +=
+				zwp_offset - bio_sectors(orig_bio);
+	}
+
+	dm_zone_unlock(q, zno, clone);
 }

drivers/md/dm.c

@@ -876,7 +876,6 @@ static void clone_endio(struct bio *bio)
 	struct dm_io *io = tio->io;
 	struct mapped_device *md = tio->io->md;
 	dm_endio_fn endio = tio->ti->type->end_io;
-	struct bio *orig_bio = io->orig_bio;
 	struct request_queue *q = bio->bi_bdev->bd_disk->queue;
 
 	if (unlikely(error == BLK_STS_TARGET)) {
@@ -891,17 +890,8 @@ static void clone_endio(struct bio *bio)
 			disable_write_zeroes(md);
 	}
 
-	/*
-	 * For zone-append bios get offset in zone of the written
-	 * sector and add that to the original bio sector pos.
-	 */
-	if (bio_op(orig_bio) == REQ_OP_ZONE_APPEND) {
-		sector_t written_sector = bio->bi_iter.bi_sector;
-		struct request_queue *q = orig_bio->bi_bdev->bd_disk->queue;
-		u64 mask = (u64)blk_queue_zone_sectors(q) - 1;
-
-		orig_bio->bi_iter.bi_sector += written_sector & mask;
-	}
+	if (blk_queue_is_zoned(q))
+		dm_zone_endio(io, bio);
 
 	if (endio) {
 		int r = endio(tio->ti, bio, &error);
@@ -1213,7 +1203,16 @@ static blk_qc_t __map_bio(struct dm_target_io *tio)
 		down(&md->swap_bios_semaphore);
 	}
 
+	/*
+	 * Check if the IO needs a special mapping due to zone append emulation
+	 * on zoned target. In this case, dm_zone_map_bio() calls the target
+	 * map operation.
+	 */
+	if (dm_emulate_zone_append(io->md))
+		r = dm_zone_map_bio(tio);
+	else
 		r = ti->type->map(ti, clone);
+
 	switch (r) {
 	case DM_MAPIO_SUBMITTED:
 		break;
@@ -1711,6 +1710,7 @@ static void cleanup_mapped_device(struct mapped_device *md)
 	mutex_destroy(&md->swap_bios_lock);
 
 	dm_mq_cleanup_mapped_device(md);
+	dm_cleanup_zoned_dev(md);
 }
 
 /*
@@ -1956,11 +1956,16 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
 		goto out;
 	}
 
+	ret = dm_table_set_restrictions(t, q, limits);
+	if (ret) {
+		old_map = ERR_PTR(ret);
+		goto out;
+	}
+
 	old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
 	rcu_assign_pointer(md->map, (void *)t);
 	md->immutable_target_type = dm_table_get_immutable_target_type(t);
 
-	dm_table_set_restrictions(t, q, limits);
 	if (old_map)
 		dm_sync_table(md);
 
@@ -2079,7 +2084,10 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
 		DMERR("Cannot calculate initial queue limits");
 		return r;
 	}
-	dm_table_set_restrictions(t, md->queue, &limits);
+	r = dm_table_set_restrictions(t, md->queue, &limits);
+	if (r)
+		return r;
+
 	blk_register_queue(md->disk);
 
 	return 0;

drivers/md/dm.h

@@ -45,6 +45,8 @@ struct dm_dev_internal {
 
 struct dm_table;
 struct dm_md_mempools;
+struct dm_target_io;
+struct dm_io;
 
 /*-----------------------------------------------------------------
  * Internal table functions.
@@ -56,7 +58,7 @@ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
 bool dm_table_has_no_data_devices(struct dm_table *table);
 int dm_calculate_queue_limits(struct dm_table *table,
 			      struct queue_limits *limits);
-void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
+int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 			      struct queue_limits *limits);
 struct list_head *dm_table_get_devices(struct dm_table *t);
 void dm_table_presuspend_targets(struct dm_table *t);
@@ -103,17 +105,25 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t);
 /*
  * Zoned targets related functions.
  */
-void dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q);
+int dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q);
+void dm_zone_endio(struct dm_io *io, struct bio *clone);
 #ifdef CONFIG_BLK_DEV_ZONED
+void dm_cleanup_zoned_dev(struct mapped_device *md);
 int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
 			unsigned int nr_zones, report_zones_cb cb, void *data);
 bool dm_is_zone_write(struct mapped_device *md, struct bio *bio);
+int dm_zone_map_bio(struct dm_target_io *io);
 #else
+static inline void dm_cleanup_zoned_dev(struct mapped_device *md) {}
 #define dm_blk_report_zones	NULL
 static inline bool dm_is_zone_write(struct mapped_device *md, struct bio *bio)
 {
 	return false;
 }
+static inline int dm_zone_map_bio(struct dm_target_io *tio)
+{
+	return DM_MAPIO_KILL;
+}
 #endif
 
 /*-----------------------------------------------------------------

include/linux/device-mapper.h

@@ -361,6 +361,12 @@ struct dm_target {
 	 * Set if we need to limit the number of in-flight bios when swapping.
 	 */
 	bool limit_swap_bios:1;
+
+	/*
+	 * Set if this target implements a a zoned device and needs emulation of
+	 * zone append operations using regular writes.
+	 */
+	bool emulate_zone_append:1;
 };
 
 void *dm_per_bio_data(struct bio *bio, size_t data_size);