[PATCH v2 00/11] dm: Improve zoned block device support

[PATCH v2 00/11] dm: Improve zoned block device support

[Damien Le Moal]

This series improve device mapper support for zoned block devices and
of targets exposing a zoned device.

The first patch improve support for user requests to reset all zones of
the target device. With the fix, such operation behave similarly to
physical block devices implementation based on the single zone reset
command with the ALL bit set.

The following 2 patches are preparatory block layer patches.

Patch 4 and 5 are 2 small fixes to DM core zoned block device support.

Patch 6 reorganizes DM core code, moving conditionally defined zoned
block device code into the new dm-zone.c file. This avoids sprinkly DM
with zone related code defined under an #ifdef CONFIG_BLK_DEV_ZONED.

Patch 7 improves DM zone report helper functions for target drivers.

Patch 8 fixes a potential problem with BIO requeue on zoned target.

Finally, patch 9 to 11 implement zone append emulation using regular
writes for target drivers that cannot natively support this BIO type.
The only target currently needing this emulation is dm-crypt. With this
change, a zoned dm-crypt device behaves exactly like a regular zoned
block device, correctly executing user zone append BIOs.

This series passes the following tests:
1) zonefs tests on top of dm-crypt with a zoned nullblk device
2) zonefs tests on top of dm-crypt+dm-linear with an SMR HDD
3) btrfs fstests on top of dm-crypt with zoned nullblk devices.

Comments are as always welcome.

Changes from v1:
* Use Christoph proposed approach for patch 1 (split reset all
  processing into different functions)
* Changed helpers introduced in patch 2 to remove the request_queue
  argument
* Improve patch 3 commit message as suggested by Christoph (explaining
  that the flag is a special case that cannot use a REQ_XXX flag)
* Changed DMWARN() into DMDEBUG in patch 11 as suggested by Milan
* Added reviewed-by tags

Damien Le Moal (11):
  block: improve handling of all zones reset operation
  block: introduce bio zone helpers
  block: introduce BIO_ZONE_WRITE_LOCKED bio flag
  dm: Fix dm_accept_partial_bio()
  dm: cleanup device_area_is_invalid()
  dm: move zone related code to dm-zone.c
  dm: Introduce dm_report_zones()
  dm: Forbid requeue of writes to zones
  dm: rearrange core declarations
  dm: introduce zone append emulation
  dm crypt: Fix zoned block device support

 block/blk-zoned.c             | 117 ++++--
 drivers/md/Makefile           |   4 +
 drivers/md/dm-core.h          |  66 ++++
 drivers/md/dm-crypt.c         |  31 +-
 drivers/md/dm-flakey.c        |   7 +-
 drivers/md/dm-linear.c        |   7 +-
 drivers/md/dm-table.c         |  21 +-
 drivers/md/dm-zone.c          | 689 ++++++++++++++++++++++++++++++++++
 drivers/md/dm.c               | 203 +++-------
 drivers/md/dm.h               |  32 +-
 include/linux/blk_types.h     |   1 +
 include/linux/blkdev.h        |  12 +
 include/linux/device-mapper.h |   9 +-
 13 files changed, 992 insertions(+), 207 deletions(-)
 create mode 100644 drivers/md/dm-zone.c

-- 
2.31.1

[PATCH v2 01/11] block: improve handling of all zones reset operation

[Damien Le Moal]

SCSI, ZNS and null_blk zoned devices support resetting all zones using
a single command (REQ_OP_ZONE_RESET_ALL), as indicated using the device
request queue flag QUEUE_FLAG_ZONE_RESETALL. This flag is not set for
device mapper targets creating zoned devices. In this case, a user
request for resetting all zones of a device is processed in
blkdev_zone_mgmt() by issuing a REQ_OP_ZONE_RESET operation for each
zone of the device. This leads to different behaviors of the
BLKRESETZONE ioctl() depending on the target device support for the
reset all operation. E.g.

blkzone reset /dev/sdX

will reset all zones of a SCSI device using a single command that will
ignore conventional, read-only or offline zones.

But a dm-linear device including conventional, read-only or offline
zones cannot be reset in the same manner as some of the single zone
reset operations issued by blkdev_zone_mgmt() will fail. E.g.:

blkzone reset /dev/dm-Y
blkzone: /dev/dm-0: BLKRESETZONE ioctl failed: Remote I/O error

To simplify applications and tools development, unify the behavior of
the all-zone reset operation by modifying blkdev_zone_mgmt() to not
issue a zone reset operation for conventional, read-only and offline
zones, thus mimicking what an actual reset-all device command does on a
device supporting REQ_OP_ZONE_RESET_ALL. This emulation is done using
the new function blkdev_zone_reset_all_emulated(). The zones needing a
reset are identified using a bitmap that is initialized using a zone
report. Since empty zones do not need a reset, also ignore these zones.
The function blkdev_zone_reset_all() is introduced for block devices
natively supporting reset all operations. blkdev_zone_mgmt() is modified
to call either function to execute an all zone reset request.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
[hch: split into multiple functions]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-zoned.c | 117 +++++++++++++++++++++++++++++++++++-----------
 1 file changed, 90 insertions(+), 27 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 250cb76ee615..0ded16b0f713 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -161,18 +161,87 @@ int blkdev_report_zones(struct block_device *bdev, sector_t sector,
 }
 EXPORT_SYMBOL_GPL(blkdev_report_zones);
 
-static inline bool blkdev_allow_reset_all_zones(struct block_device *bdev,
-						sector_t sector,
-						sector_t nr_sectors)
+static inline unsigned long *blk_alloc_zone_bitmap(int node,
+						   unsigned int nr_zones)
 {
-	if (!blk_queue_zone_resetall(bdev_get_queue(bdev)))
-		return false;
+	return kcalloc_node(BITS_TO_LONGS(nr_zones), sizeof(unsigned long),
+			    GFP_NOIO, node);
+}
 
+static int blk_zone_need_reset_cb(struct blk_zone *zone, unsigned int idx,
+				  void *data)
+{
 	/*
-	 * REQ_OP_ZONE_RESET_ALL can be executed only if the number of sectors
-	 * of the applicable zone range is the entire disk.
+	 * For an all-zones reset, ignore conventional, empty, read-only
+	 * and offline zones.
 	 */
-	return !sector && nr_sectors == get_capacity(bdev->bd_disk);
+	switch (zone->cond) {
+	case BLK_ZONE_COND_NOT_WP:
+	case BLK_ZONE_COND_EMPTY:
+	case BLK_ZONE_COND_READONLY:
+	case BLK_ZONE_COND_OFFLINE:
+		return 0;
+	default:
+		set_bit(idx, (unsigned long *)data);
+		return 0;
+	}
+}
+
+static int blkdev_zone_reset_all_emulated(struct block_device *bdev,
+					  gfp_t gfp_mask)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+	sector_t capacity = get_capacity(bdev->bd_disk);
+	sector_t zone_sectors = blk_queue_zone_sectors(q);
+	unsigned long *need_reset;
+	struct bio *bio = NULL;
+	sector_t sector;
+	int ret;
+
+	need_reset = blk_alloc_zone_bitmap(q->node, q->nr_zones);
+	if (!need_reset)
+		return -ENOMEM;
+
+	ret = bdev->bd_disk->fops->report_zones(bdev->bd_disk, 0,
+				q->nr_zones, blk_zone_need_reset_cb,
+				need_reset);
+	if (ret < 0)
+		goto out_free_need_reset;
+
+	ret = 0;
+	while (sector < capacity) {
+		if (!test_bit(blk_queue_zone_no(q, sector), need_reset)) {
+			sector += zone_sectors;
+			continue;
+		}
+		bio = blk_next_bio(bio, 0, gfp_mask);
+		bio_set_dev(bio, bdev);
+		bio->bi_opf = REQ_OP_ZONE_RESET | REQ_SYNC;
+		bio->bi_iter.bi_sector = sector;
+		sector += zone_sectors;
+
+		/* This may take a while, so be nice to others */
+		cond_resched();
+	}
+
+	if (bio) {
+		ret = submit_bio_wait(bio);
+		bio_put(bio);
+	}
+
+out_free_need_reset:
+	kfree(need_reset);
+	return ret;
+}
+
+static int blkdev_zone_reset_all(struct block_device *bdev, gfp_t gfp_mask)
+{
+	struct bio bio;
+
+	bio_init(&bio, NULL, 0);
+	bio_set_dev(&bio, bdev);
+	bio.bi_opf = REQ_OP_ZONE_RESET_ALL | REQ_SYNC;
+	return submit_bio_wait(&bio);
 }
 
 /**
@@ -200,7 +269,7 @@ int blkdev_zone_mgmt(struct block_device *bdev, enum req_opf op,
 	sector_t capacity = get_capacity(bdev->bd_disk);
 	sector_t end_sector = sector + nr_sectors;
 	struct bio *bio = NULL;
-	int ret;
+	int ret = 0;
 
 	if (!blk_queue_is_zoned(q))
 		return -EOPNOTSUPP;
@@ -222,20 +291,21 @@ int blkdev_zone_mgmt(struct block_device *bdev, enum req_opf op,
 	if ((nr_sectors & (zone_sectors - 1)) && end_sector != capacity)
 		return -EINVAL;
 
+	/*
+	 * In the case of a zone reset operation over all zones,
+	 * REQ_OP_ZONE_RESET_ALL can be used with devices supporting this
+	 * command. For other devices, we emulate this command behavior by
+	 * identifying the zones needing a reset.
+	 */
+	if (op == REQ_OP_ZONE_RESET && sector == 0 && nr_sectors == capacity) {
+		if (!blk_queue_zone_resetall(q))
+			return blkdev_zone_reset_all_emulated(bdev, gfp_mask);
+		return blkdev_zone_reset_all(bdev, gfp_mask);
+	}
+
 	while (sector < end_sector) {
 		bio = blk_next_bio(bio, 0, gfp_mask);
 		bio_set_dev(bio, bdev);
-
-		/*
-		 * Special case for the zone reset operation that reset all
-		 * zones, this is useful for applications like mkfs.
-		 */
-		if (op == REQ_OP_ZONE_RESET &&
-		    blkdev_allow_reset_all_zones(bdev, sector, nr_sectors)) {
-			bio->bi_opf = REQ_OP_ZONE_RESET_ALL | REQ_SYNC;
-			break;
-		}
-
 		bio->bi_opf = op | REQ_SYNC;
 		bio->bi_iter.bi_sector = sector;
 		sector += zone_sectors;
@@ -396,13 +466,6 @@ int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode,
 	return ret;
 }
 
-static inline unsigned long *blk_alloc_zone_bitmap(int node,
-						   unsigned int nr_zones)
-{
-	return kcalloc_node(BITS_TO_LONGS(nr_zones), sizeof(unsigned long),
-			    GFP_NOIO, node);
-}
-
 void blk_queue_free_zone_bitmaps(struct request_queue *q)
 {
 	kfree(q->conv_zones_bitmap);
-- 
2.31.1

[PATCH v2 02/11] block: introduce bio zone helpers

[Damien Le Moal]

Introduce the helper functions bio_zone_no() and bio_zone_is_seq().
Both are the BIO counterparts of the request helpers blk_rq_zone_no()
and blk_rq_zone_is_seq(), respectively returning the number of the
target zone of a bio and true if the BIO target zone is sequential.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 include/linux/blkdev.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f69c75bd6d27..2db0f376f5d9 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1008,6 +1008,18 @@ static inline unsigned int blk_rq_stats_sectors(const struct request *rq)
 /* Helper to convert BLK_ZONE_ZONE_XXX to its string format XXX */
 const char *blk_zone_cond_str(enum blk_zone_cond zone_cond);
 
+static inline unsigned int bio_zone_no(struct bio *bio)
+{
+	return blk_queue_zone_no(bdev_get_queue(bio->bi_bdev),
+				 bio->bi_iter.bi_sector);
+}
+
+static inline unsigned int bio_zone_is_seq(struct bio *bio)
+{
+	return blk_queue_zone_is_seq(bdev_get_queue(bio->bi_bdev),
+				     bio->bi_iter.bi_sector);
+}
+
 static inline unsigned int blk_rq_zone_no(struct request *rq)
 {
 	return blk_queue_zone_no(rq->q, blk_rq_pos(rq));
-- 
2.31.1

[PATCH v2 03/11] block: introduce BIO_ZONE_WRITE_LOCKED bio flag

[Damien Le Moal]

Introduce the BIO flag BIO_ZONE_WRITE_LOCKED to indicate that a BIO owns
the write lock of the zone it is targeting. This is the counterpart of
the struct request flag RQF_ZONE_WRITE_LOCKED.

This new BIO flag is reserved for now for zone write locking control
for device mapper targets exposing a zoned block device. Since in this
case, the lock flag must not be propagated to the struct request that
will be used to process the BIO, a BIO private flag is used rather than
changing the RQF_ZONE_WRITE_LOCKED request flag into a common REQ_XXX
flag that could be used for both BIO and request. This avoids conflicts
down the stack with the block IO scheduler zone write locking
(in mq-deadline).

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/blk_types.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index db026b6ec15a..e5cf12f102a2 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -304,6 +304,7 @@ enum {
 	BIO_CGROUP_ACCT,	/* has been accounted to a cgroup */
 	BIO_TRACKED,		/* set if bio goes through the rq_qos path */
 	BIO_REMAPPED,
+	BIO_ZONE_WRITE_LOCKED,	/* Owns a zoned device zone write lock */
 	BIO_FLAG_LAST
 };
 
-- 
2.31.1

[PATCH v2 04/11] dm: Fix dm_accept_partial_bio()

[Damien Le Moal]

Fix dm_accept_partial_bio() to actually check that zone management
commands are not passed as explained in the function documentation
comment. Also, since a zone append operation cannot be split, add
REQ_OP_ZONE_APPEND as a forbidden command.

White lines are added around the group of BUG_ON() calls to make the
code more legible.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 drivers/md/dm.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ca2aedd8ee7d..a9211575bfed 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1237,8 +1237,9 @@ static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
 
 /*
  * A target may call dm_accept_partial_bio only from the map routine.  It is
- * allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_RESET,
- * REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH.
+ * allowed for all bio types except REQ_PREFLUSH, zone management operations
+ * (REQ_OP_ZONE_RESET, REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and
+ * REQ_OP_ZONE_FINISH) and zone append writes.
  *
  * dm_accept_partial_bio informs the dm that the target only wants to process
  * additional n_sectors sectors of the bio and the rest of the data should be
@@ -1268,9 +1269,13 @@ void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
 {
 	struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
 	unsigned bi_size = bio->bi_iter.bi_size >> SECTOR_SHIFT;
+
 	BUG_ON(bio->bi_opf & REQ_PREFLUSH);
+	BUG_ON(op_is_zone_mgmt(bio_op(bio)));
+	BUG_ON(bio_op(bio) == REQ_OP_ZONE_APPEND);
 	BUG_ON(bi_size > *tio->len_ptr);
 	BUG_ON(n_sectors > bi_size);
+
 	*tio->len_ptr -= bi_size - n_sectors;
 	bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
 }
-- 
2.31.1

[PATCH v2 05/11] dm: cleanup device_area_is_invalid()

[Damien Le Moal]

In device_area_is_invalid(), use bdev_is_zoned() instead of open
coding the test on the zoned model returned by bdev_zoned_model().

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 drivers/md/dm-table.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index ee47a332b462..21fd9cd4da32 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -249,7 +249,7 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 	 * If the target is mapped to zoned block device(s), check
 	 * that the zones are not partially mapped.
 	 */
-	if (bdev_zoned_model(bdev) != BLK_ZONED_NONE) {
+	if (bdev_is_zoned(bdev)) {
 		unsigned int zone_sectors = bdev_zone_sectors(bdev);
 
 		if (start & (zone_sectors - 1)) {
-- 
2.31.1

[PATCH v2 06/11] dm: move zone related code to dm-zone.c

[Damien Le Moal]

Move core and table code used for zoned targets and conditionally
defined with #ifdef CONFIG_BLK_DEV_ZONED to the new file dm-zone.c.
This file is conditionally compiled depending on CONFIG_BLK_DEV_ZONED.
The small helper dm_set_zones_restrictions() is introduced to
initialize a mapped device request queue zone attributes in
dm_table_set_restrictions().

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 drivers/md/Makefile   |   4 ++
 drivers/md/dm-table.c |  14 ++----
 drivers/md/dm-zone.c  | 102 ++++++++++++++++++++++++++++++++++++++++++
 drivers/md/dm.c       |  78 --------------------------------
 drivers/md/dm.h       |  11 +++++
 5 files changed, 120 insertions(+), 89 deletions(-)
 create mode 100644 drivers/md/dm-zone.c

diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index ef7ddc27685c..a74aaf8b1445 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -92,6 +92,10 @@ ifeq ($(CONFIG_DM_UEVENT),y)
 dm-mod-objs			+= dm-uevent.o
 endif
 
+ifeq ($(CONFIG_BLK_DEV_ZONED),y)
+dm-mod-objs			+= dm-zone.o
+endif
+
 ifeq ($(CONFIG_DM_VERITY_FEC),y)
 dm-verity-objs			+= dm-verity-fec.o
 endif
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 21fd9cd4da32..dd9f648ab598 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -2064,17 +2064,9 @@ 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, 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.
-	 */
-#ifdef CONFIG_BLK_DEV_ZONED
-	if (blk_queue_is_zoned(q)) {
-		WARN_ON_ONCE(queue_is_mq(q));
-		q->nr_zones = blkdev_nr_zones(t->md->disk);
-	}
-#endif
+	/* For a zoned target, setup the zones related queue attributes */
+	if (blk_queue_is_zoned(q))
+		dm_set_zones_restrictions(t, q);
 
 	dm_update_keyslot_manager(q, t);
 	blk_queue_update_readahead(q);
diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
new file mode 100644
index 000000000000..3243c42b7951
--- /dev/null
+++ b/drivers/md/dm-zone.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#include <linux/blkdev.h>
+
+#include "dm-core.h"
+
+/*
+ * 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;
+	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;
+		}
+
+		args.tgt = tgt;
+		ret = tgt->type->report_zones(tgt, &args,
+					      nr_zones - args.zone_idx);
+		if (ret < 0)
+			goto out;
+	} while (args.zone_idx < nr_zones &&
+		 args.next_sector < get_capacity(disk));
+
+	ret = args.zone_idx;
+out:
+	dm_put_live_table(md, srcu_idx);
+	return ret;
+}
+
+int dm_report_zones_cb(struct blk_zone *zone, unsigned int idx, void *data)
+{
+	struct dm_report_zones_args *args = data;
+	sector_t sector_diff = args->tgt->begin - args->start;
+
+	/*
+	 * Ignore zones beyond the target range.
+	 */
+	if (zone->start >= args->start + args->tgt->len)
+		return 0;
+
+	/*
+	 * Remap the start sector and write pointer position of the zone
+	 * to match its position in the target range.
+	 */
+	zone->start += sector_diff;
+	if (zone->type != BLK_ZONE_TYPE_CONVENTIONAL) {
+		if (zone->cond == BLK_ZONE_COND_FULL)
+			zone->wp = zone->start + zone->len;
+		else if (zone->cond == BLK_ZONE_COND_EMPTY)
+			zone->wp = zone->start;
+		else
+			zone->wp += sector_diff;
+	}
+
+	args->next_sector = zone->start + zone->len;
+	return args->orig_cb(zone, args->zone_idx++, args->orig_data);
+}
+EXPORT_SYMBOL_GPL(dm_report_zones_cb);
+
+void dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q)
+{
+	if (!blk_queue_is_zoned(q))
+		return;
+
+	/*
+	 * 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.
+	 */
+	WARN_ON_ONCE(queue_is_mq(q));
+	q->nr_zones = blkdev_nr_zones(t->md->disk);
+}
+
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index a9211575bfed..45d2dc2ee844 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -444,84 +444,6 @@ static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 	return dm_get_geometry(md, geo);
 }
 
-#ifdef CONFIG_BLK_DEV_ZONED
-int dm_report_zones_cb(struct blk_zone *zone, unsigned int idx, void *data)
-{
-	struct dm_report_zones_args *args = data;
-	sector_t sector_diff = args->tgt->begin - args->start;
-
-	/*
-	 * Ignore zones beyond the target range.
-	 */
-	if (zone->start >= args->start + args->tgt->len)
-		return 0;
-
-	/*
-	 * Remap the start sector and write pointer position of the zone
-	 * to match its position in the target range.
-	 */
-	zone->start += sector_diff;
-	if (zone->type != BLK_ZONE_TYPE_CONVENTIONAL) {
-		if (zone->cond == BLK_ZONE_COND_FULL)
-			zone->wp = zone->start + zone->len;
-		else if (zone->cond == BLK_ZONE_COND_EMPTY)
-			zone->wp = zone->start;
-		else
-			zone->wp += sector_diff;
-	}
-
-	args->next_sector = zone->start + zone->len;
-	return args->orig_cb(zone, args->zone_idx++, args->orig_data);
-}
-EXPORT_SYMBOL_GPL(dm_report_zones_cb);
-
-static 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;
-	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;
-		}
-
-		args.tgt = tgt;
-		ret = tgt->type->report_zones(tgt, &args,
-					      nr_zones - args.zone_idx);
-		if (ret < 0)
-			goto out;
-	} while (args.zone_idx < nr_zones &&
-		 args.next_sector < get_capacity(disk));
-
-	ret = args.zone_idx;
-out:
-	dm_put_live_table(md, srcu_idx);
-	return ret;
-}
-#else
-#define dm_blk_report_zones		NULL
-#endif /* CONFIG_BLK_DEV_ZONED */
-
 static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
 			    struct block_device **bdev)
 {
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index b441ad772c18..fdf1536a4b62 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -100,6 +100,17 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t);
  */
 #define dm_target_hybrid(t) (dm_target_bio_based(t) && dm_target_request_based(t))
 
+/*
+ * Zoned targets related functions.
+ */
+void dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q);
+#ifdef CONFIG_BLK_DEV_ZONED
+int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
+			unsigned int nr_zones, report_zones_cb cb, void *data);
+#else
+#define dm_blk_report_zones	NULL
+#endif
+
 /*-----------------------------------------------------------------
  * A registry of target types.
  *---------------------------------------------------------------*/
-- 
2.31.1

[PATCH v2 07/11] dm: Introduce dm_report_zones()

[Damien Le Moal]

To simplify the implementation of the report_zones operation of a zoned
target, introduce the function dm_report_zones() to set a target
mapping start sector in struct dm_report_zones_args and call
blkdev_report_zones(). This new function is exported and the report
zones callback function dm_report_zones_cb() is not.

dm-linear, dm-flakey and dm-crypt are modified to use dm_report_zones().

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 drivers/md/dm-crypt.c         |  7 +++----
 drivers/md/dm-flakey.c        |  7 +++----
 drivers/md/dm-linear.c        |  7 +++----
 drivers/md/dm-zone.c          | 23 ++++++++++++++++++++---
 include/linux/device-mapper.h |  3 ++-
 5 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index b0ab080f2567..f410ceee51d7 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -3138,11 +3138,10 @@ static int crypt_report_zones(struct dm_target *ti,
 		struct dm_report_zones_args *args, unsigned int nr_zones)
 {
 	struct crypt_config *cc = ti->private;
-	sector_t sector = cc->start + dm_target_offset(ti, args->next_sector);
 
-	args->start = cc->start;
-	return blkdev_report_zones(cc->dev->bdev, sector, nr_zones,
-				   dm_report_zones_cb, args);
+	return dm_report_zones(cc->dev->bdev, cc->start,
+			cc->start + dm_target_offset(ti, args->next_sector),
+			args, nr_zones);
 }
 #else
 #define crypt_report_zones NULL
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index b7fee9936f05..5877220c01ed 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -463,11 +463,10 @@ static int flakey_report_zones(struct dm_target *ti,
 		struct dm_report_zones_args *args, unsigned int nr_zones)
 {
 	struct flakey_c *fc = ti->private;
-	sector_t sector = flakey_map_sector(ti, args->next_sector);
 
-	args->start = fc->start;
-	return blkdev_report_zones(fc->dev->bdev, sector, nr_zones,
-				   dm_report_zones_cb, args);
+	return dm_report_zones(fc->dev->bdev, fc->start,
+			       flakey_map_sector(ti, args->next_sector),
+			       args, nr_zones);
 }
 #else
 #define flakey_report_zones NULL
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 92db0f5e7f28..c91f1e2e2f65 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -140,11 +140,10 @@ static int linear_report_zones(struct dm_target *ti,
 		struct dm_report_zones_args *args, unsigned int nr_zones)
 {
 	struct linear_c *lc = ti->private;
-	sector_t sector = linear_map_sector(ti, args->next_sector);
 
-	args->start = lc->start;
-	return blkdev_report_zones(lc->dev->bdev, sector, nr_zones,
-				   dm_report_zones_cb, args);
+	return dm_report_zones(lc->dev->bdev, lc->start,
+			       linear_map_sector(ti, args->next_sector),
+			       args, nr_zones);
 }
 #else
 #define linear_report_zones NULL
diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
index 3243c42b7951..b42474043249 100644
--- a/drivers/md/dm-zone.c
+++ b/drivers/md/dm-zone.c
@@ -56,7 +56,8 @@ int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
 	return ret;
 }
 
-int dm_report_zones_cb(struct blk_zone *zone, unsigned int idx, void *data)
+static int dm_report_zones_cb(struct blk_zone *zone, unsigned int idx,
+			      void *data)
 {
 	struct dm_report_zones_args *args = data;
 	sector_t sector_diff = args->tgt->begin - args->start;
@@ -84,7 +85,24 @@ int dm_report_zones_cb(struct blk_zone *zone, unsigned int idx, void *data)
 	args->next_sector = zone->start + zone->len;
 	return args->orig_cb(zone, args->zone_idx++, args->orig_data);
 }
-EXPORT_SYMBOL_GPL(dm_report_zones_cb);
+
+/*
+ * Helper for drivers of zoned targets to implement struct target_type
+ * report_zones operation.
+ */
+int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector,
+		    struct dm_report_zones_args *args, unsigned int nr_zones)
+{
+	/*
+	 * Set the target mapping start sector first so that
+	 * dm_report_zones_cb() can correctly remap zone information.
+	 */
+	args->start = start;
+
+	return blkdev_report_zones(bdev, sector, nr_zones,
+				   dm_report_zones_cb, args);
+}
+EXPORT_SYMBOL_GPL(dm_report_zones);
 
 void dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q)
 {
@@ -99,4 +117,3 @@ void dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q)
 	WARN_ON_ONCE(queue_is_mq(q));
 	q->nr_zones = blkdev_nr_zones(t->md->disk);
 }
-
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index ff700fb6ce1d..caea0a079d2d 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -478,7 +478,8 @@ struct dm_report_zones_args {
 	/* must be filled by ->report_zones before calling dm_report_zones_cb */
 	sector_t start;
 };
-int dm_report_zones_cb(struct blk_zone *zone, unsigned int idx, void *data);
+int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector,
+		    struct dm_report_zones_args *args, unsigned int nr_zones);
 #endif /* CONFIG_BLK_DEV_ZONED */
 
 /*
-- 
2.31.1

[PATCH v2 08/11] dm: Forbid requeue of writes to zones

[Damien Le Moal]

A target map method requesting the requeue of a bio with
DM_MAPIO_REQUEUE or completing it with DM_ENDIO_REQUEUE can cause
unaligned write errors if the bio is a write operation targeting a
sequential zone. If a zoned target request such a requeue, warn about
it and kill the IO.

The function dm_is_zone_write() is introduced to detect write operations
to zoned targets.

This change does not affect the target drivers supporting zoned devices
and exposing a zoned device, namely dm-crypt, dm-linear and dm-flakey as
none of these targets ever request a requeue.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 drivers/md/dm-zone.c | 17 +++++++++++++++++
 drivers/md/dm.c      | 18 +++++++++++++++---
 drivers/md/dm.h      |  5 +++++
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
index b42474043249..edc3bbb45637 100644
--- a/drivers/md/dm-zone.c
+++ b/drivers/md/dm-zone.c
@@ -104,6 +104,23 @@ int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector,
 }
 EXPORT_SYMBOL_GPL(dm_report_zones);
 
+bool dm_is_zone_write(struct mapped_device *md, struct bio *bio)
+{
+	struct request_queue *q = md->queue;
+
+	if (!blk_queue_is_zoned(q))
+		return false;
+
+	switch (bio_op(bio)) {
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE_SAME:
+	case REQ_OP_WRITE:
+		return !op_is_flush(bio->bi_opf) && bio_sectors(bio);
+	default:
+		return false;
+	}
+}
+
 void dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q)
 {
 	if (!blk_queue_is_zoned(q))
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 45d2dc2ee844..4426019a89cc 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -846,11 +846,15 @@ static void dec_pending(struct dm_io *io, blk_status_t error)
 			 * Target requested pushing back the I/O.
 			 */
 			spin_lock_irqsave(&md->deferred_lock, flags);
-			if (__noflush_suspending(md))
+			if (__noflush_suspending(md) &&
+			    !WARN_ON_ONCE(dm_is_zone_write(md, bio)))
 				/* NOTE early return due to BLK_STS_DM_REQUEUE below */
 				bio_list_add_head(&md->deferred, io->orig_bio);
 			else
-				/* noflush suspend was interrupted. */
+				/*
+				 * noflush suspend was interrupted or this is
+				 * a write to a zoned target.
+				 */
 				io->status = BLK_STS_IOERR;
 			spin_unlock_irqrestore(&md->deferred_lock, flags);
 		}
@@ -947,7 +951,15 @@ static void clone_endio(struct bio *bio)
 		int r = endio(tio->ti, bio, &error);
 		switch (r) {
 		case DM_ENDIO_REQUEUE:
-			error = BLK_STS_DM_REQUEUE;
+			/*
+			 * Requeuing writes to a sequential zone of a zoned
+			 * target will break the sequential write pattern:
+			 * fail such IO.
+			 */
+			if (WARN_ON_ONCE(dm_is_zone_write(md, bio)))
+				error = BLK_STS_IOERR;
+			else
+				error = BLK_STS_DM_REQUEUE;
 			fallthrough;
 		case DM_ENDIO_DONE:
 			break;
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index fdf1536a4b62..39c243258e24 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -107,8 +107,13 @@ void dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q);
 #ifdef CONFIG_BLK_DEV_ZONED
 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);
 #else
 #define dm_blk_report_zones	NULL
+static inline bool dm_is_zone_write(struct mapped_device *md, struct bio *bio)
+{
+	return false;
+}
 #endif
 
 /*-----------------------------------------------------------------
-- 
2.31.1

[PATCH v2 09/11] dm: rearrange core declarations

[Damien Le Moal]

Move the definitions of struct dm_target_io, struct dm_io and of the
bits of the flags field of struct mapped_device from dm.c to dm-core.h
to make them usable from dm-zone.c.
For the same reason, declare dec_pending() in dm-core.h after renaming
it to dm_io_dec_pending(). And for symmetry of the function names,
introduce the inline helper dm_io_inc_pending() instead of directly
using atomic_inc() calls.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 drivers/md/dm-core.h | 52 ++++++++++++++++++++++++++++++++++++++
 drivers/md/dm.c      | 59 ++++++--------------------------------------
 2 files changed, 59 insertions(+), 52 deletions(-)

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index 5953ff2bd260..cfabc1c91f9f 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -116,6 +116,19 @@ struct mapped_device {
 	struct srcu_struct io_barrier;
 };
 
+/*
+ * Bits for the flags field of struct mapped_device.
+ */
+#define DMF_BLOCK_IO_FOR_SUSPEND 0
+#define DMF_SUSPENDED 1
+#define DMF_FROZEN 2
+#define DMF_FREEING 3
+#define DMF_DELETING 4
+#define DMF_NOFLUSH_SUSPENDING 5
+#define DMF_DEFERRED_REMOVE 6
+#define DMF_SUSPENDED_INTERNALLY 7
+#define DMF_POST_SUSPENDING 8
+
 void disable_discard(struct mapped_device *md);
 void disable_write_same(struct mapped_device *md);
 void disable_write_zeroes(struct mapped_device *md);
@@ -173,6 +186,45 @@ struct dm_table {
 #endif
 };
 
+/*
+ * One of these is allocated per clone bio.
+ */
+#define DM_TIO_MAGIC 7282014
+struct dm_target_io {
+	unsigned int magic;
+	struct dm_io *io;
+	struct dm_target *ti;
+	unsigned int target_bio_nr;
+	unsigned int *len_ptr;
+	bool inside_dm_io;
+	struct bio clone;
+};
+
+/*
+ * One of these is allocated per original bio.
+ * It contains the first clone used for that original.
+ */
+#define DM_IO_MAGIC 5191977
+struct dm_io {
+	unsigned int magic;
+	struct mapped_device *md;
+	blk_status_t status;
+	atomic_t io_count;
+	struct bio *orig_bio;
+	unsigned long start_time;
+	spinlock_t endio_lock;
+	struct dm_stats_aux stats_aux;
+	/* last member of dm_target_io is 'struct bio' */
+	struct dm_target_io tio;
+};
+
+static inline void dm_io_inc_pending(struct dm_io *io)
+{
+	atomic_inc(&io->io_count);
+}
+
+void dm_io_dec_pending(struct dm_io *io, blk_status_t error);
+
 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
 {
 	return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 4426019a89cc..563504163b74 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -74,38 +74,6 @@ struct clone_info {
 	unsigned sector_count;
 };
 
-/*
- * One of these is allocated per clone bio.
- */
-#define DM_TIO_MAGIC 7282014
-struct dm_target_io {
-	unsigned magic;
-	struct dm_io *io;
-	struct dm_target *ti;
-	unsigned target_bio_nr;
-	unsigned *len_ptr;
-	bool inside_dm_io;
-	struct bio clone;
-};
-
-/*
- * One of these is allocated per original bio.
- * It contains the first clone used for that original.
- */
-#define DM_IO_MAGIC 5191977
-struct dm_io {
-	unsigned magic;
-	struct mapped_device *md;
-	blk_status_t status;
-	atomic_t io_count;
-	struct bio *orig_bio;
-	unsigned long start_time;
-	spinlock_t endio_lock;
-	struct dm_stats_aux stats_aux;
-	/* last member of dm_target_io is 'struct bio' */
-	struct dm_target_io tio;
-};
-
 #define DM_TARGET_IO_BIO_OFFSET (offsetof(struct dm_target_io, clone))
 #define DM_IO_BIO_OFFSET \
 	(offsetof(struct dm_target_io, clone) + offsetof(struct dm_io, tio))
@@ -137,19 +105,6 @@ EXPORT_SYMBOL_GPL(dm_bio_get_target_bio_nr);
 
 #define MINOR_ALLOCED ((void *)-1)
 
-/*
- * Bits for the md->flags field.
- */
-#define DMF_BLOCK_IO_FOR_SUSPEND 0
-#define DMF_SUSPENDED 1
-#define DMF_FROZEN 2
-#define DMF_FREEING 3
-#define DMF_DELETING 4
-#define DMF_NOFLUSH_SUSPENDING 5
-#define DMF_DEFERRED_REMOVE 6
-#define DMF_SUSPENDED_INTERNALLY 7
-#define DMF_POST_SUSPENDING 8
-
 #define DM_NUMA_NODE NUMA_NO_NODE
 static int dm_numa_node = DM_NUMA_NODE;
 
@@ -825,7 +780,7 @@ static int __noflush_suspending(struct mapped_device *md)
  * Decrements the number of outstanding ios that a bio has been
  * cloned into, completing the original io if necc.
  */
-static void dec_pending(struct dm_io *io, blk_status_t error)
+void dm_io_dec_pending(struct dm_io *io, blk_status_t error)
 {
 	unsigned long flags;
 	blk_status_t io_error;
@@ -978,7 +933,7 @@ static void clone_endio(struct bio *bio)
 	}
 
 	free_tio(tio);
-	dec_pending(io, error);
+	dm_io_dec_pending(io, error);
 }
 
 /*
@@ -1247,7 +1202,7 @@ static blk_qc_t __map_bio(struct dm_target_io *tio)
 	 * anything, the target has assumed ownership of
 	 * this io.
 	 */
-	atomic_inc(&io->io_count);
+	dm_io_inc_pending(io);
 	sector = clone->bi_iter.bi_sector;
 
 	if (unlikely(swap_bios_limit(ti, clone))) {
@@ -1273,7 +1228,7 @@ static blk_qc_t __map_bio(struct dm_target_io *tio)
 			up(&md->swap_bios_semaphore);
 		}
 		free_tio(tio);
-		dec_pending(io, BLK_STS_IOERR);
+		dm_io_dec_pending(io, BLK_STS_IOERR);
 		break;
 	case DM_MAPIO_REQUEUE:
 		if (unlikely(swap_bios_limit(ti, clone))) {
@@ -1281,7 +1236,7 @@ static blk_qc_t __map_bio(struct dm_target_io *tio)
 			up(&md->swap_bios_semaphore);
 		}
 		free_tio(tio);
-		dec_pending(io, BLK_STS_DM_REQUEUE);
+		dm_io_dec_pending(io, BLK_STS_DM_REQUEUE);
 		break;
 	default:
 		DMWARN("unimplemented target map return value: %d", r);
@@ -1570,7 +1525,7 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
 
 	if (bio->bi_opf & REQ_PREFLUSH) {
 		error = __send_empty_flush(&ci);
-		/* dec_pending submits any data associated with flush */
+		/* dm_io_dec_pending submits any data associated with flush */
 	} else if (op_is_zone_mgmt(bio_op(bio))) {
 		ci.bio = bio;
 		ci.sector_count = 0;
@@ -1611,7 +1566,7 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
 	}
 
 	/* drop the extra reference count */
-	dec_pending(ci.io, errno_to_blk_status(error));
+	dm_io_dec_pending(ci.io, errno_to_blk_status(error));
 	return ret;
 }
 
-- 
2.31.1

[PATCH v2 10/11] dm: introduce zone append emulation

[Damien Le Moal]

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>
---
 drivers/md/dm-core.h          |  14 +
 drivers/md/dm-table.c         |  19 +-
 drivers/md/dm-zone.c          | 615 ++++++++++++++++++++++++++++++++--
 drivers/md/dm.c               |  39 ++-
 drivers/md/dm.h               |  18 +-
 include/linux/device-mapper.h |   6 +
 6 files changed, 657 insertions(+), 54 deletions(-)

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index cfabc1c91f9f..2dbb0c7ff720 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -114,6 +114,12 @@ struct mapped_device {
 	bool init_tio_pdu:1;
 
 	struct srcu_struct io_barrier;
+
+#ifdef CONFIG_BLK_DEV_ZONED
+	unsigned int nr_zones;
+	spinlock_t zwp_offset_lock;
+	unsigned int *zwp_offset;
+#endif
 };
 
 /*
@@ -128,6 +134,7 @@ 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 +150,13 @@ 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 {
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index dd9f648ab598..21fdccfb16cf 100644
--- a/drivers/md/dm-table.c
+++ b/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,
-			       struct queue_limits *limits)
+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)
diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
index edc3bbb45637..c298bab28390 100644
--- a/drivers/md/dm-zone.c
+++ b/drivers/md/dm-zone.c
@@ -4,55 +4,73 @@
  */
 
 #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
+#define DM_ZONE_UPDATING_WP_OFST	(DM_ZONE_INVALID_WP_OFST - 1)
+
 /*
- * 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 +139,551 @@ 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_init_zoned_dev(struct mapped_device *md)
 {
-	if (!blk_queue_is_zoned(q))
-		return;
+	spin_lock_init(&md->zwp_offset_lock);
+}
+
+void dm_cleanup_zoned_dev(struct mapped_device *md)
+{
+	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 zone_sectors = blk_queue_zone_sectors(md->queue);
+	unsigned int zno = bio_zone_no(orig_bio);
+	unsigned long flags;
+	bool good_io = false;
+
+	spin_lock_irqsave(&md->zwp_offset_lock, flags);
+
+	/*
+	 * 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 (md->zwp_offset[zno] == DM_ZONE_INVALID_WP_OFST) {
+		unsigned int wp_offset;
+		int ret;
+
+		md->zwp_offset[zno] = DM_ZONE_UPDATING_WP_OFST;
+
+		spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
+		ret = dm_update_zone_wp_offset(md, zno, &wp_offset);
+		spin_lock_irqsave(&md->zwp_offset_lock, flags);
+
+		if (ret) {
+			md->zwp_offset[zno] = DM_ZONE_INVALID_WP_OFST;
+			goto out;
+		}
+		md->zwp_offset[zno] = wp_offset;
+	} else if (md->zwp_offset[zno] == DM_ZONE_UPDATING_WP_OFST) {
+		DMWARN_LIMIT("Invalid DM_ZONE_UPDATING_WP_OFST state");
+		goto out;
+	}
+
+	switch (bio_op(orig_bio)) {
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE_SAME:
+	case REQ_OP_WRITE:
+		break;
+	case REQ_OP_ZONE_RESET:
+	case REQ_OP_ZONE_FINISH:
+		goto good;
+	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 + md->zwp_offset[zno];
+		break;
+	default:
+		DMWARN_LIMIT("Invalid BIO operation");
+		goto out;
+	}
+
+	/* Cannot write to a full zone */
+	if (md->zwp_offset[zno] >= zone_sectors)
+		goto out;
+
+	/* Writes must be aligned to the zone write pointer */
+	if ((clone->bi_iter.bi_sector & (zone_sectors - 1)) != md->zwp_offset[zno])
+		goto out;
+
+good:
+	good_io = true;
+
+out:
+	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
+
+	return good_io;
+}
+
+/*
+ * 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);
+	blk_status_t sts = BLK_STS_OK;
+	unsigned long flags;
+
+	spin_lock_irqsave(&md->zwp_offset_lock, flags);
+
+	/* Update the zone wp offset */
+	switch (bio_op(orig_bio)) {
+	case REQ_OP_ZONE_RESET:
+		md->zwp_offset[zno] = 0;
+		break;
+	case REQ_OP_ZONE_FINISH:
+		md->zwp_offset[zno] = blk_queue_zone_sectors(md->queue);
+		break;
+	case REQ_OP_WRITE_ZEROES:
+	case REQ_OP_WRITE_SAME:
+	case REQ_OP_WRITE:
+		md->zwp_offset[zno] += nr_sectors;
+		break;
+	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");
+			sts = BLK_STS_IOERR;
+			break;
+		}
+		md->zwp_offset[zno] += nr_sectors;
+		break;
+	default:
+		DMWARN_LIMIT("Invalid BIO operation");
+		sts = BLK_STS_IOERR;
+		break;
+	}
+
+	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
+
+	return sts;
+}
+
+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 long flags;
+	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);
+
+	spin_lock_irqsave(&md->zwp_offset_lock, flags);
+	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.
+		 */
+		if (md->zwp_offset[zno] != DM_ZONE_UPDATING_WP_OFST)
+			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.
+		 */
+		if (WARN_ON_ONCE(md->zwp_offset[zno] < bio_sectors(orig_bio)))
+			md->zwp_offset[zno] = DM_ZONE_INVALID_WP_OFST;
+		else
+			orig_bio->bi_iter.bi_sector +=
+				md->zwp_offset[zno] - bio_sectors(orig_bio);
+	}
+	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
+
+	dm_zone_unlock(q, zno, clone);
 }
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 563504163b74..5038bf522b0d 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -875,7 +875,6 @@ 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)) {
@@ -890,17 +889,8 @@ 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);
 	}
 
-	r = ti->type->map(ti, clone);
+	/*
+	 * Check if the IO needs a special mapping due to zone append emulation
+	 * on zoned target. In this case, dm_zone_map_begin() 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;
@@ -1757,6 +1756,7 @@ static struct mapped_device *alloc_dev(int minor)
 	INIT_LIST_HEAD(&md->uevent_list);
 	INIT_LIST_HEAD(&md->table_devices);
 	spin_lock_init(&md->uevent_lock);
+	dm_init_zoned_dev(md);
 
 	/*
 	 * default to bio-based until DM table is loaded and md->type
@@ -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;
@@ -2188,6 +2196,7 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
 		       dm_device_name(md), atomic_read(&md->holders));
 
 	dm_sysfs_exit(md);
+	dm_cleanup_zoned_dev(md);
 	dm_table_destroy(__unbind(md));
 	free_dev(md);
 }
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 39c243258e24..65f20d8cc415 100644
--- a/drivers/md/dm.h
+++ b/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.
@@ -56,8 +58,8 @@ 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,
-			       struct queue_limits *limits);
+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);
 void dm_table_presuspend_undo_targets(struct dm_table *t);
@@ -103,17 +105,27 @@ 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_init_zoned_dev(struct mapped_device *md);
+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_init_zoned_dev(struct mapped_device *md) {}
+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
 
 /*-----------------------------------------------------------------
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index caea0a079d2d..7457d49acf9a 100644
--- a/include/linux/device-mapper.h
+++ b/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);
-- 
2.31.1

[PATCH v2 11/11] dm crypt: Fix zoned block device support

[Damien Le Moal]

Zone append BIOs (REQ_OP_ZONE_APPEND) always specify the start sector
of the zone to be written instead of the actual sector location to
write. The write location is determined by the device and returned to
the host upon completion of the operation. This interface, while simple
and efficient for writing into sequential zones of a zoned block
device, is incompatible with the use of sector values to calculate a
cypher block IV. All data written in a zone end up using the same IV
values corresponding to the first sectors of the zone, but read
operation will specify any sector within the zone resulting in an IV
mismatch between encryption and decryption.

To solve this problem, report to DM core that zone append operations are
not supported. This result in the zone append operations being emulated
using regular write operations.

Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 drivers/md/dm-crypt.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index f410ceee51d7..50f4cbd600d5 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -3280,14 +3280,28 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 	cc->start = tmpll;
 
-	/*
-	 * For zoned block devices, we need to preserve the issuer write
-	 * ordering. To do so, disable write workqueues and force inline
-	 * encryption completion.
-	 */
 	if (bdev_is_zoned(cc->dev->bdev)) {
+		/*
+		 * For zoned block devices, we need to preserve the issuer write
+		 * ordering. To do so, disable write workqueues and force inline
+		 * encryption completion.
+		 */
 		set_bit(DM_CRYPT_NO_WRITE_WORKQUEUE, &cc->flags);
 		set_bit(DM_CRYPT_WRITE_INLINE, &cc->flags);
+
+		/*
+		 * All zone append writes to a zone of a zoned block device will
+		 * have the same BIO sector, the start of the zone. When the
+		 * cypher IV mode uses sector values, all data targeting a
+		 * zone will be encrypted using the first sector numbers of the
+		 * zone. This will not result in write errors but will
+		 * cause most reads to fail as reads will use the sector values
+		 * for the actual data locations, resulting in IV mismatch.
+		 * To avoid this problem, ask DM core to emulate zone append
+		 * operations with regular writes.
+		 */
+		DMDEBUG("Zone append operations will be emulated");
+		ti->emulate_zone_append = true;
 	}
 
 	if (crypt_integrity_aead(cc) || cc->integrity_iv_size) {
-- 
2.31.1

Re: [PATCH v2 01/11] block: improve handling of all zones reset operation

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> SCSI, ZNS and null_blk zoned devices support resetting all zones using
> a single command (REQ_OP_ZONE_RESET_ALL), as indicated using the device
> request queue flag QUEUE_FLAG_ZONE_RESETALL. This flag is not set for
> device mapper targets creating zoned devices. In this case, a user
> request for resetting all zones of a device is processed in
> blkdev_zone_mgmt() by issuing a REQ_OP_ZONE_RESET operation for each
> zone of the device. This leads to different behaviors of the
> BLKRESETZONE ioctl() depending on the target device support for the
> reset all operation. E.g.
> 
> blkzone reset /dev/sdX
> 
> will reset all zones of a SCSI device using a single command that will
> ignore conventional, read-only or offline zones.
> 
> But a dm-linear device including conventional, read-only or offline
> zones cannot be reset in the same manner as some of the single zone
> reset operations issued by blkdev_zone_mgmt() will fail. E.g.:
> 
> blkzone reset /dev/dm-Y
> blkzone: /dev/dm-0: BLKRESETZONE ioctl failed: Remote I/O error
> 
> To simplify applications and tools development, unify the behavior of
> the all-zone reset operation by modifying blkdev_zone_mgmt() to not
> issue a zone reset operation for conventional, read-only and offline
> zones, thus mimicking what an actual reset-all device command does on a
> device supporting REQ_OP_ZONE_RESET_ALL. This emulation is done using
> the new function blkdev_zone_reset_all_emulated(). The zones needing a
> reset are identified using a bitmap that is initialized using a zone
> report. Since empty zones do not need a reset, also ignore these zones.
> The function blkdev_zone_reset_all() is introduced for block devices
> natively supporting reset all operations. blkdev_zone_mgmt() is modified
> to call either function to execute an all zone reset request.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> [hch: split into multiple functions]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/blk-zoned.c | 117 +++++++++++++++++++++++++++++++++++-----------
>   1 file changed, 90 insertions(+), 27 deletions(-)
> Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 02/11] block: introduce bio zone helpers

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> Introduce the helper functions bio_zone_no() and bio_zone_is_seq().
> Both are the BIO counterparts of the request helpers blk_rq_zone_no()
> and blk_rq_zone_is_seq(), respectively returning the number of the
> target zone of a bio and true if the BIO target zone is sequential.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> ---
>   include/linux/blkdev.h | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index f69c75bd6d27..2db0f376f5d9 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1008,6 +1008,18 @@ static inline unsigned int blk_rq_stats_sectors(const struct request *rq)
>   /* Helper to convert BLK_ZONE_ZONE_XXX to its string format XXX */
>   const char *blk_zone_cond_str(enum blk_zone_cond zone_cond);
>   
> +static inline unsigned int bio_zone_no(struct bio *bio)
> +{
> +	return blk_queue_zone_no(bdev_get_queue(bio->bi_bdev),
> +				 bio->bi_iter.bi_sector);
> +}
> +
> +static inline unsigned int bio_zone_is_seq(struct bio *bio)
> +{
> +	return blk_queue_zone_is_seq(bdev_get_queue(bio->bi_bdev),
> +				     bio->bi_iter.bi_sector);
> +}
> +
>   static inline unsigned int blk_rq_zone_no(struct request *rq)
>   {
>   	return blk_queue_zone_no(rq->q, blk_rq_pos(rq));
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 03/11] block: introduce BIO_ZONE_WRITE_LOCKED bio flag

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> Introduce the BIO flag BIO_ZONE_WRITE_LOCKED to indicate that a BIO owns
> the write lock of the zone it is targeting. This is the counterpart of
> the struct request flag RQF_ZONE_WRITE_LOCKED.
> 
> This new BIO flag is reserved for now for zone write locking control
> for device mapper targets exposing a zoned block device. Since in this
> case, the lock flag must not be propagated to the struct request that
> will be used to process the BIO, a BIO private flag is used rather than
> changing the RQF_ZONE_WRITE_LOCKED request flag into a common REQ_XXX
> flag that could be used for both BIO and request. This avoids conflicts
> down the stack with the block IO scheduler zone write locking
> (in mq-deadline).
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>   include/linux/blk_types.h | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index db026b6ec15a..e5cf12f102a2 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -304,6 +304,7 @@ enum {
>   	BIO_CGROUP_ACCT,	/* has been accounted to a cgroup */
>   	BIO_TRACKED,		/* set if bio goes through the rq_qos path */
>   	BIO_REMAPPED,
> +	BIO_ZONE_WRITE_LOCKED,	/* Owns a zoned device zone write lock */
>   	BIO_FLAG_LAST
>   };
>   
> 
I would have merged this with the patch actually using it, but this is 
probably a personal preference.

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 04/11] dm: Fix dm_accept_partial_bio()

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> Fix dm_accept_partial_bio() to actually check that zone management
> commands are not passed as explained in the function documentation
> comment. Also, since a zone append operation cannot be split, add
> REQ_OP_ZONE_APPEND as a forbidden command.
> 
> White lines are added around the group of BUG_ON() calls to make the
> code more legible.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>   drivers/md/dm.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index ca2aedd8ee7d..a9211575bfed 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -1237,8 +1237,9 @@ static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
>   
>   /*
>    * A target may call dm_accept_partial_bio only from the map routine.  It is
> - * allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_RESET,
> - * REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH.
> + * allowed for all bio types except REQ_PREFLUSH, zone management operations
> + * (REQ_OP_ZONE_RESET, REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and
> + * REQ_OP_ZONE_FINISH) and zone append writes.
>    *
>    * dm_accept_partial_bio informs the dm that the target only wants to process
>    * additional n_sectors sectors of the bio and the rest of the data should be
> @@ -1268,9 +1269,13 @@ void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
>   {
>   	struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
>   	unsigned bi_size = bio->bi_iter.bi_size >> SECTOR_SHIFT;
> +
>   	BUG_ON(bio->bi_opf & REQ_PREFLUSH);
> +	BUG_ON(op_is_zone_mgmt(bio_op(bio)));
> +	BUG_ON(bio_op(bio) == REQ_OP_ZONE_APPEND);
>   	BUG_ON(bi_size > *tio->len_ptr);
>   	BUG_ON(n_sectors > bi_size);
> +
>   	*tio->len_ptr -= bi_size - n_sectors;
>   	bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
>   }
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 05/11] dm: cleanup device_area_is_invalid()

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> In device_area_is_invalid(), use bdev_is_zoned() instead of open
> coding the test on the zoned model returned by bdev_zoned_model().
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>   drivers/md/dm-table.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index ee47a332b462..21fd9cd4da32 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -249,7 +249,7 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
>   	 * If the target is mapped to zoned block device(s), check
>   	 * that the zones are not partially mapped.
>   	 */
> -	if (bdev_zoned_model(bdev) != BLK_ZONED_NONE) {
> +	if (bdev_is_zoned(bdev)) {
>   		unsigned int zone_sectors = bdev_zone_sectors(bdev);
>   
>   		if (start & (zone_sectors - 1)) {
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 06/11] dm: move zone related code to dm-zone.c

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> Move core and table code used for zoned targets and conditionally
> defined with #ifdef CONFIG_BLK_DEV_ZONED to the new file dm-zone.c.
> This file is conditionally compiled depending on CONFIG_BLK_DEV_ZONED.
> The small helper dm_set_zones_restrictions() is introduced to
> initialize a mapped device request queue zone attributes in
> dm_table_set_restrictions().
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>   drivers/md/Makefile   |   4 ++
>   drivers/md/dm-table.c |  14 ++----
>   drivers/md/dm-zone.c  | 102 ++++++++++++++++++++++++++++++++++++++++++
>   drivers/md/dm.c       |  78 --------------------------------
>   drivers/md/dm.h       |  11 +++++
>   5 files changed, 120 insertions(+), 89 deletions(-)
>   create mode 100644 drivers/md/dm-zone.c
> Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 07/11] dm: Introduce dm_report_zones()

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> To simplify the implementation of the report_zones operation of a zoned
> target, introduce the function dm_report_zones() to set a target
> mapping start sector in struct dm_report_zones_args and call
> blkdev_report_zones(). This new function is exported and the report
> zones callback function dm_report_zones_cb() is not.
> 
> dm-linear, dm-flakey and dm-crypt are modified to use dm_report_zones().
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>   drivers/md/dm-crypt.c         |  7 +++----
>   drivers/md/dm-flakey.c        |  7 +++----
>   drivers/md/dm-linear.c        |  7 +++----
>   drivers/md/dm-zone.c          | 23 ++++++++++++++++++++---
>   include/linux/device-mapper.h |  3 ++-
>   5 files changed, 31 insertions(+), 16 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 08/11] dm: Forbid requeue of writes to zones

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> A target map method requesting the requeue of a bio with
> DM_MAPIO_REQUEUE or completing it with DM_ENDIO_REQUEUE can cause
> unaligned write errors if the bio is a write operation targeting a
> sequential zone. If a zoned target request such a requeue, warn about
> it and kill the IO.
> 
> The function dm_is_zone_write() is introduced to detect write operations
> to zoned targets.
> 
> This change does not affect the target drivers supporting zoned devices
> and exposing a zoned device, namely dm-crypt, dm-linear and dm-flakey as
> none of these targets ever request a requeue.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> ---
>   drivers/md/dm-zone.c | 17 +++++++++++++++++
>   drivers/md/dm.c      | 18 +++++++++++++++---
>   drivers/md/dm.h      |  5 +++++
>   3 files changed, 37 insertions(+), 3 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 09/11] dm: rearrange core declarations

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> Move the definitions of struct dm_target_io, struct dm_io and of the
> bits of the flags field of struct mapped_device from dm.c to dm-core.h
> to make them usable from dm-zone.c.
> For the same reason, declare dec_pending() in dm-core.h after renaming
> it to dm_io_dec_pending(). And for symmetry of the function names,
> introduce the inline helper dm_io_inc_pending() instead of directly
> using atomic_inc() calls.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> ---
>   drivers/md/dm-core.h | 52 ++++++++++++++++++++++++++++++++++++++
>   drivers/md/dm.c      | 59 ++++++--------------------------------------
>   2 files changed, 59 insertions(+), 52 deletions(-)
> I've never been a fan of private structures.

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 10/11] dm: introduce zone append emulation

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> 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>
> ---
>   drivers/md/dm-core.h          |  14 +
>   drivers/md/dm-table.c         |  19 +-
>   drivers/md/dm-zone.c          | 615 ++++++++++++++++++++++++++++++++--
>   drivers/md/dm.c               |  39 ++-
>   drivers/md/dm.h               |  18 +-
>   include/linux/device-mapper.h |   6 +
>   6 files changed, 657 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
> index cfabc1c91f9f..2dbb0c7ff720 100644
> --- a/drivers/md/dm-core.h
> +++ b/drivers/md/dm-core.h
> @@ -114,6 +114,12 @@ struct mapped_device {
>   	bool init_tio_pdu:1;
>   
>   	struct srcu_struct io_barrier;
> +
> +#ifdef CONFIG_BLK_DEV_ZONED
> +	unsigned int nr_zones;
> +	spinlock_t zwp_offset_lock;
> +	unsigned int *zwp_offset;
> +#endif
>   };
>   
>   /*
> @@ -128,6 +134,7 @@ 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 +150,13 @@ 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 {
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index dd9f648ab598..21fdccfb16cf 100644
> --- a/drivers/md/dm-table.c
> +++ b/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,
> -			       struct queue_limits *limits)
> +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)
> diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
> index edc3bbb45637..c298bab28390 100644
> --- a/drivers/md/dm-zone.c
> +++ b/drivers/md/dm-zone.c
> @@ -4,55 +4,73 @@
>    */
>   
>   #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
> +#define DM_ZONE_UPDATING_WP_OFST	(DM_ZONE_INVALID_WP_OFST - 1)
> +
>   /*
> - * 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 +139,551 @@ 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_init_zoned_dev(struct mapped_device *md)
>   {
> -	if (!blk_queue_is_zoned(q))
> -		return;
> +	spin_lock_init(&md->zwp_offset_lock);
> +}
> +
> +void dm_cleanup_zoned_dev(struct mapped_device *md)
> +{
> +	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 zone_sectors = blk_queue_zone_sectors(md->queue);
> +	unsigned int zno = bio_zone_no(orig_bio);
> +	unsigned long flags;
> +	bool good_io = false;
> +
> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
> +
> +	/*
> +	 * 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 (md->zwp_offset[zno] == DM_ZONE_INVALID_WP_OFST) {
> +		unsigned int wp_offset;
> +		int ret;
> +
> +		md->zwp_offset[zno] = DM_ZONE_UPDATING_WP_OFST;
> +
> +		spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
> +		ret = dm_update_zone_wp_offset(md, zno, &wp_offset);
> +		spin_lock_irqsave(&md->zwp_offset_lock, flags);
> +
> +		if (ret) {
> +			md->zwp_offset[zno] = DM_ZONE_INVALID_WP_OFST;
> +			goto out;
> +		}
> +		md->zwp_offset[zno] = wp_offset;
> +	} else if (md->zwp_offset[zno] == DM_ZONE_UPDATING_WP_OFST) {
> +		DMWARN_LIMIT("Invalid DM_ZONE_UPDATING_WP_OFST state");
> +		goto out;
> +	}
> +
> +	switch (bio_op(orig_bio)) {
> +	case REQ_OP_WRITE_ZEROES:
> +	case REQ_OP_WRITE_SAME:
> +	case REQ_OP_WRITE:
> +		break;
> +	case REQ_OP_ZONE_RESET:
> +	case REQ_OP_ZONE_FINISH:
> +		goto good;
> +	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 + md->zwp_offset[zno];
> +		break;
> +	default:
> +		DMWARN_LIMIT("Invalid BIO operation");
> +		goto out;
> +	}
> +
> +	/* Cannot write to a full zone */
> +	if (md->zwp_offset[zno] >= zone_sectors)
> +		goto out;
> +
> +	/* Writes must be aligned to the zone write pointer */
> +	if ((clone->bi_iter.bi_sector & (zone_sectors - 1)) != md->zwp_offset[zno])
> +		goto out;
> +
> +good:
> +	good_io = true;
> +
> +out:
> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);

I'm not happy with the spinlock. Can't the same effect be achieved with 
some clever READ_ONCE()/WRITE_ONCE/cmpexch magic?
Especially as you have a separate 'zone lock' mechanism ...

> +
> +	return good_io;
> +}
> +
> +/*
> + * 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);
> +	blk_status_t sts = BLK_STS_OK;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
> +
> +	/* Update the zone wp offset */
> +	switch (bio_op(orig_bio)) {
> +	case REQ_OP_ZONE_RESET:
> +		md->zwp_offset[zno] = 0;
> +		break;
> +	case REQ_OP_ZONE_FINISH:
> +		md->zwp_offset[zno] = blk_queue_zone_sectors(md->queue);
> +		break;
> +	case REQ_OP_WRITE_ZEROES:
> +	case REQ_OP_WRITE_SAME:
> +	case REQ_OP_WRITE:
> +		md->zwp_offset[zno] += nr_sectors;
> +		break;
> +	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");
> +			sts = BLK_STS_IOERR;
> +			break;
> +		}
> +		md->zwp_offset[zno] += nr_sectors;
> +		break;
> +	default:
> +		DMWARN_LIMIT("Invalid BIO operation");
> +		sts = BLK_STS_IOERR;
> +		break;
> +	}
> +
> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);

You don't need the spinlock here; using WRITE_ONCE() should be sufficient.

> +
> +	return sts;
> +}
> +
> +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 long flags;
> +	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);
> +
> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
> +	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.
> +		 */
> +		if (md->zwp_offset[zno] != DM_ZONE_UPDATING_WP_OFST)
> +			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.
> +		 */
> +		if (WARN_ON_ONCE(md->zwp_offset[zno] < bio_sectors(orig_bio)))
> +			md->zwp_offset[zno] = DM_ZONE_INVALID_WP_OFST;
> +		else
> +			orig_bio->bi_iter.bi_sector +=
> +				md->zwp_offset[zno] - bio_sectors(orig_bio);
> +	}
> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
> +

Similar comments to the spinlock here.

> +	dm_zone_unlock(q, zno, clone);
>   }
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 563504163b74..5038bf522b0d 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -875,7 +875,6 @@ 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)) {
> @@ -890,17 +889,8 @@ 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);
>   	}
>   
> -	r = ti->type->map(ti, clone);
> +	/*
> +	 * Check if the IO needs a special mapping due to zone append emulation
> +	 * on zoned target. In this case, dm_zone_map_begin() 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;
> @@ -1757,6 +1756,7 @@ static struct mapped_device *alloc_dev(int minor)
>   	INIT_LIST_HEAD(&md->uevent_list);
>   	INIT_LIST_HEAD(&md->table_devices);
>   	spin_lock_init(&md->uevent_lock);
> +	dm_init_zoned_dev(md);
>   
>   	/*
>   	 * default to bio-based until DM table is loaded and md->type
> @@ -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;
> @@ -2188,6 +2196,7 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
>   		       dm_device_name(md), atomic_read(&md->holders));
>   
>   	dm_sysfs_exit(md);
> +	dm_cleanup_zoned_dev(md);
>   	dm_table_destroy(__unbind(md));
>   	free_dev(md);
>   }
> diff --git a/drivers/md/dm.h b/drivers/md/dm.h
> index 39c243258e24..65f20d8cc415 100644
> --- a/drivers/md/dm.h
> +++ b/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.
> @@ -56,8 +58,8 @@ 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,
> -			       struct queue_limits *limits);
> +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);
>   void dm_table_presuspend_undo_targets(struct dm_table *t);
> @@ -103,17 +105,27 @@ 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_init_zoned_dev(struct mapped_device *md);
> +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_init_zoned_dev(struct mapped_device *md) {}
> +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
>   
>   /*-----------------------------------------------------------------
> diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
> index caea0a079d2d..7457d49acf9a 100644
> --- a/include/linux/device-mapper.h
> +++ b/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);
> 
Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 11/11] dm crypt: Fix zoned block device support

[Hannes Reinecke]

On 5/20/21 6:22 AM, Damien Le Moal wrote:
> Zone append BIOs (REQ_OP_ZONE_APPEND) always specify the start sector
> of the zone to be written instead of the actual sector location to
> write. The write location is determined by the device and returned to
> the host upon completion of the operation. This interface, while simple
> and efficient for writing into sequential zones of a zoned block
> device, is incompatible with the use of sector values to calculate a
> cypher block IV. All data written in a zone end up using the same IV
> values corresponding to the first sectors of the zone, but read
> operation will specify any sector within the zone resulting in an IV
> mismatch between encryption and decryption.
> 
> To solve this problem, report to DM core that zone append operations are
> not supported. This result in the zone append operations being emulated
> using regular write operations.
> 
> Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> ---
>   drivers/md/dm-crypt.c | 24 +++++++++++++++++++-----
>   1 file changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
> index f410ceee51d7..50f4cbd600d5 100644
> --- a/drivers/md/dm-crypt.c
> +++ b/drivers/md/dm-crypt.c
> @@ -3280,14 +3280,28 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
>   	}
>   	cc->start = tmpll;
>   
> -	/*
> -	 * For zoned block devices, we need to preserve the issuer write
> -	 * ordering. To do so, disable write workqueues and force inline
> -	 * encryption completion.
> -	 */
>   	if (bdev_is_zoned(cc->dev->bdev)) {
> +		/*
> +		 * For zoned block devices, we need to preserve the issuer write
> +		 * ordering. To do so, disable write workqueues and force inline
> +		 * encryption completion.
> +		 */
>   		set_bit(DM_CRYPT_NO_WRITE_WORKQUEUE, &cc->flags);
>   		set_bit(DM_CRYPT_WRITE_INLINE, &cc->flags);
> +
> +		/*
> +		 * All zone append writes to a zone of a zoned block device will
> +		 * have the same BIO sector, the start of the zone. When the
> +		 * cypher IV mode uses sector values, all data targeting a
> +		 * zone will be encrypted using the first sector numbers of the
> +		 * zone. This will not result in write errors but will
> +		 * cause most reads to fail as reads will use the sector values
> +		 * for the actual data locations, resulting in IV mismatch.
> +		 * To avoid this problem, ask DM core to emulate zone append
> +		 * operations with regular writes.
> +		 */
> +		DMDEBUG("Zone append operations will be emulated");
> +		ti->emulate_zone_append = true;
>   	}
>   
>   	if (crypt_integrity_aead(cc) || cc->integrity_iv_size) {
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 10/11] dm: introduce zone append emulation

[Damien Le Moal]

On 2021/05/20 15:10, Hannes Reinecke wrote:
[...]
>> +/*
>> + * 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 zone_sectors = blk_queue_zone_sectors(md->queue);
>> +	unsigned int zno = bio_zone_no(orig_bio);
>> +	unsigned long flags;
>> +	bool good_io = false;
>> +
>> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
>> +
>> +	/*
>> +	 * 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 (md->zwp_offset[zno] == DM_ZONE_INVALID_WP_OFST) {
>> +		unsigned int wp_offset;
>> +		int ret;
>> +
>> +		md->zwp_offset[zno] = DM_ZONE_UPDATING_WP_OFST;
>> +
>> +		spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
>> +		ret = dm_update_zone_wp_offset(md, zno, &wp_offset);
>> +		spin_lock_irqsave(&md->zwp_offset_lock, flags);
>> +
>> +		if (ret) {
>> +			md->zwp_offset[zno] = DM_ZONE_INVALID_WP_OFST;
>> +			goto out;
>> +		}
>> +		md->zwp_offset[zno] = wp_offset;
>> +	} else if (md->zwp_offset[zno] == DM_ZONE_UPDATING_WP_OFST) {
>> +		DMWARN_LIMIT("Invalid DM_ZONE_UPDATING_WP_OFST state");
>> +		goto out;
>> +	}
>> +
>> +	switch (bio_op(orig_bio)) {
>> +	case REQ_OP_WRITE_ZEROES:
>> +	case REQ_OP_WRITE_SAME:
>> +	case REQ_OP_WRITE:
>> +		break;
>> +	case REQ_OP_ZONE_RESET:
>> +	case REQ_OP_ZONE_FINISH:
>> +		goto good;
>> +	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 + md->zwp_offset[zno];
>> +		break;
>> +	default:
>> +		DMWARN_LIMIT("Invalid BIO operation");
>> +		goto out;
>> +	}
>> +
>> +	/* Cannot write to a full zone */
>> +	if (md->zwp_offset[zno] >= zone_sectors)
>> +		goto out;
>> +
>> +	/* Writes must be aligned to the zone write pointer */
>> +	if ((clone->bi_iter.bi_sector & (zone_sectors - 1)) != md->zwp_offset[zno])
>> +		goto out;
>> +
>> +good:
>> +	good_io = true;
>> +
>> +out:
>> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
> 
> I'm not happy with the spinlock. Can't the same effect be achieved with 
> some clever READ_ONCE()/WRITE_ONCE/cmpexch magic?
> Especially as you have a separate 'zone lock' mechanism ...

hmmm... Let me see. Given that what the bio completion is relatively simple, it
may be possible. With more coffee, I amy be able to come up with something clever.

> 
>> +
>> +	return good_io;
>> +}
>> +
>> +/*
>> + * 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);
>> +	blk_status_t sts = BLK_STS_OK;
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
>> +
>> +	/* Update the zone wp offset */
>> +	switch (bio_op(orig_bio)) {
>> +	case REQ_OP_ZONE_RESET:
>> +		md->zwp_offset[zno] = 0;
>> +		break;
>> +	case REQ_OP_ZONE_FINISH:
>> +		md->zwp_offset[zno] = blk_queue_zone_sectors(md->queue);
>> +		break;
>> +	case REQ_OP_WRITE_ZEROES:
>> +	case REQ_OP_WRITE_SAME:
>> +	case REQ_OP_WRITE:
>> +		md->zwp_offset[zno] += nr_sectors;
>> +		break;
>> +	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");
>> +			sts = BLK_STS_IOERR;
>> +			break;
>> +		}
>> +		md->zwp_offset[zno] += nr_sectors;
>> +		break;
>> +	default:
>> +		DMWARN_LIMIT("Invalid BIO operation");
>> +		sts = BLK_STS_IOERR;
>> +		break;
>> +	}
>> +
>> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
> 
> You don't need the spinlock here; using WRITE_ONCE() should be sufficient.

If other references to zwp_offset use READ_ONCE(), no ?

[...]
>> +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 long flags;
>> +	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);
>> +
>> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
>> +	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.
>> +		 */
>> +		if (md->zwp_offset[zno] != DM_ZONE_UPDATING_WP_OFST)
>> +			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.
>> +		 */
>> +		if (WARN_ON_ONCE(md->zwp_offset[zno] < bio_sectors(orig_bio)))
>> +			md->zwp_offset[zno] = DM_ZONE_INVALID_WP_OFST;
>> +		else
>> +			orig_bio->bi_iter.bi_sector +=
>> +				md->zwp_offset[zno] - bio_sectors(orig_bio);
>> +	}
>> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
>> +
> 
> Similar comments to the spinlock here.

OK.

Thanks for the review.


-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 10/11] dm: introduce zone append emulation

[Hannes Reinecke]

On 5/20/21 8:25 AM, Damien Le Moal wrote:
> On 2021/05/20 15:10, Hannes Reinecke wrote:
> [...]
>>> +/*
>>> + * 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 zone_sectors = blk_queue_zone_sectors(md->queue);
>>> +	unsigned int zno = bio_zone_no(orig_bio);
>>> +	unsigned long flags;
>>> +	bool good_io = false;
>>> +
>>> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
>>> +
>>> +	/*
>>> +	 * 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 (md->zwp_offset[zno] == DM_ZONE_INVALID_WP_OFST) {
>>> +		unsigned int wp_offset;
>>> +		int ret;
>>> +
>>> +		md->zwp_offset[zno] = DM_ZONE_UPDATING_WP_OFST;
>>> +
>>> +		spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
>>> +		ret = dm_update_zone_wp_offset(md, zno, &wp_offset);
>>> +		spin_lock_irqsave(&md->zwp_offset_lock, flags);
>>> +
>>> +		if (ret) {
>>> +			md->zwp_offset[zno] = DM_ZONE_INVALID_WP_OFST;
>>> +			goto out;
>>> +		}
>>> +		md->zwp_offset[zno] = wp_offset;
>>> +	} else if (md->zwp_offset[zno] == DM_ZONE_UPDATING_WP_OFST) {
>>> +		DMWARN_LIMIT("Invalid DM_ZONE_UPDATING_WP_OFST state");
>>> +		goto out;
>>> +	}
>>> +
>>> +	switch (bio_op(orig_bio)) {
>>> +	case REQ_OP_WRITE_ZEROES:
>>> +	case REQ_OP_WRITE_SAME:
>>> +	case REQ_OP_WRITE:
>>> +		break;
>>> +	case REQ_OP_ZONE_RESET:
>>> +	case REQ_OP_ZONE_FINISH:
>>> +		goto good;
>>> +	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 + md->zwp_offset[zno];
>>> +		break;
>>> +	default:
>>> +		DMWARN_LIMIT("Invalid BIO operation");
>>> +		goto out;
>>> +	}
>>> +
>>> +	/* Cannot write to a full zone */
>>> +	if (md->zwp_offset[zno] >= zone_sectors)
>>> +		goto out;
>>> +
>>> +	/* Writes must be aligned to the zone write pointer */
>>> +	if ((clone->bi_iter.bi_sector & (zone_sectors - 1)) != md->zwp_offset[zno])
>>> +		goto out;
>>> +
>>> +good:
>>> +	good_io = true;
>>> +
>>> +out:
>>> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
>>
>> I'm not happy with the spinlock. Can't the same effect be achieved with
>> some clever READ_ONCE()/WRITE_ONCE/cmpexch magic?
>> Especially as you have a separate 'zone lock' mechanism ...
> 
> hmmm... Let me see. Given that what the bio completion is relatively simple, it
> may be possible. With more coffee, I amy be able to come up with something clever.
> 
More coffee is always a good idea :-)
I would look at killing the intermediate state UPDATING_WP_OFST and only 
update the pointer on endio (or if it failed).
That way we would need to update the pointer only once if we have a 
final state, and don't need to do the double update you are doing now.

>>
>>> +
>>> +	return good_io;
>>> +}
>>> +
>>> +/*
>>> + * 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);
>>> +	blk_status_t sts = BLK_STS_OK;
>>> +	unsigned long flags;
>>> +
>>> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
>>> +
>>> +	/* Update the zone wp offset */
>>> +	switch (bio_op(orig_bio)) {
>>> +	case REQ_OP_ZONE_RESET:
>>> +		md->zwp_offset[zno] = 0;
>>> +		break;
>>> +	case REQ_OP_ZONE_FINISH:
>>> +		md->zwp_offset[zno] = blk_queue_zone_sectors(md->queue);
>>> +		break;
>>> +	case REQ_OP_WRITE_ZEROES:
>>> +	case REQ_OP_WRITE_SAME:
>>> +	case REQ_OP_WRITE:
>>> +		md->zwp_offset[zno] += nr_sectors;
>>> +		break;
>>> +	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");
>>> +			sts = BLK_STS_IOERR;
>>> +			break;
>>> +		}
>>> +		md->zwp_offset[zno] += nr_sectors;
>>> +		break;
>>> +	default:
>>> +		DMWARN_LIMIT("Invalid BIO operation");
>>> +		sts = BLK_STS_IOERR;
>>> +		break;
>>> +	}
>>> +
>>> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
>>
>> You don't need the spinlock here; using WRITE_ONCE() should be sufficient.
> 
> If other references to zwp_offset use READ_ONCE(), no ?
> 
Why, but of course.
If you touch one you have to touch all :-)

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

Re: [PATCH v2 10/11] dm: introduce zone append emulation

[Damien Le Moal]

On 2021/05/20 15:47, Hannes Reinecke wrote:
> On 5/20/21 8:25 AM, Damien Le Moal wrote:
>> On 2021/05/20 15:10, Hannes Reinecke wrote:
>> [...]
>>>> +/*
>>>> + * 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 zone_sectors = blk_queue_zone_sectors(md->queue);
>>>> +	unsigned int zno = bio_zone_no(orig_bio);
>>>> +	unsigned long flags;
>>>> +	bool good_io = false;
>>>> +
>>>> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
>>>> +
>>>> +	/*
>>>> +	 * 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 (md->zwp_offset[zno] == DM_ZONE_INVALID_WP_OFST) {
>>>> +		unsigned int wp_offset;
>>>> +		int ret;
>>>> +
>>>> +		md->zwp_offset[zno] = DM_ZONE_UPDATING_WP_OFST;
>>>> +
>>>> +		spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
>>>> +		ret = dm_update_zone_wp_offset(md, zno, &wp_offset);
>>>> +		spin_lock_irqsave(&md->zwp_offset_lock, flags);
>>>> +
>>>> +		if (ret) {
>>>> +			md->zwp_offset[zno] = DM_ZONE_INVALID_WP_OFST;
>>>> +			goto out;
>>>> +		}
>>>> +		md->zwp_offset[zno] = wp_offset;
>>>> +	} else if (md->zwp_offset[zno] == DM_ZONE_UPDATING_WP_OFST) {
>>>> +		DMWARN_LIMIT("Invalid DM_ZONE_UPDATING_WP_OFST state");
>>>> +		goto out;
>>>> +	}
>>>> +
>>>> +	switch (bio_op(orig_bio)) {
>>>> +	case REQ_OP_WRITE_ZEROES:
>>>> +	case REQ_OP_WRITE_SAME:
>>>> +	case REQ_OP_WRITE:
>>>> +		break;
>>>> +	case REQ_OP_ZONE_RESET:
>>>> +	case REQ_OP_ZONE_FINISH:
>>>> +		goto good;
>>>> +	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 + md->zwp_offset[zno];
>>>> +		break;
>>>> +	default:
>>>> +		DMWARN_LIMIT("Invalid BIO operation");
>>>> +		goto out;
>>>> +	}
>>>> +
>>>> +	/* Cannot write to a full zone */
>>>> +	if (md->zwp_offset[zno] >= zone_sectors)
>>>> +		goto out;
>>>> +
>>>> +	/* Writes must be aligned to the zone write pointer */
>>>> +	if ((clone->bi_iter.bi_sector & (zone_sectors - 1)) != md->zwp_offset[zno])
>>>> +		goto out;
>>>> +
>>>> +good:
>>>> +	good_io = true;
>>>> +
>>>> +out:
>>>> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
>>>
>>> I'm not happy with the spinlock. Can't the same effect be achieved with
>>> some clever READ_ONCE()/WRITE_ONCE/cmpexch magic?
>>> Especially as you have a separate 'zone lock' mechanism ...
>>
>> hmmm... Let me see. Given that what the bio completion is relatively simple, it
>> may be possible. With more coffee, I amy be able to come up with something clever.
>>
> More coffee is always a good idea :-)
> I would look at killing the intermediate state UPDATING_WP_OFST and only 
> update the pointer on endio (or if it failed).
> That way we would need to update the pointer only once if we have a 
> final state, and don't need to do the double update you are doing now.

Good point. That should work. Definitely more coffee needed :)

> 
>>>
>>>> +
>>>> +	return good_io;
>>>> +}
>>>> +
>>>> +/*
>>>> + * 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);
>>>> +	blk_status_t sts = BLK_STS_OK;
>>>> +	unsigned long flags;
>>>> +
>>>> +	spin_lock_irqsave(&md->zwp_offset_lock, flags);
>>>> +
>>>> +	/* Update the zone wp offset */
>>>> +	switch (bio_op(orig_bio)) {
>>>> +	case REQ_OP_ZONE_RESET:
>>>> +		md->zwp_offset[zno] = 0;
>>>> +		break;
>>>> +	case REQ_OP_ZONE_FINISH:
>>>> +		md->zwp_offset[zno] = blk_queue_zone_sectors(md->queue);
>>>> +		break;
>>>> +	case REQ_OP_WRITE_ZEROES:
>>>> +	case REQ_OP_WRITE_SAME:
>>>> +	case REQ_OP_WRITE:
>>>> +		md->zwp_offset[zno] += nr_sectors;
>>>> +		break;
>>>> +	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");
>>>> +			sts = BLK_STS_IOERR;
>>>> +			break;
>>>> +		}
>>>> +		md->zwp_offset[zno] += nr_sectors;
>>>> +		break;
>>>> +	default:
>>>> +		DMWARN_LIMIT("Invalid BIO operation");
>>>> +		sts = BLK_STS_IOERR;
>>>> +		break;
>>>> +	}
>>>> +
>>>> +	spin_unlock_irqrestore(&md->zwp_offset_lock, flags);
>>>
>>> You don't need the spinlock here; using WRITE_ONCE() should be sufficient.
>>
>> If other references to zwp_offset use READ_ONCE(), no ?
>>
> Why, but of course.
> If you touch one you have to touch all :-)
> 
> Cheers,
> 
> Hannes
> 


-- 
Damien Le Moal
Western Digital Research