Merge tag 'for-4.13/dm-changes' of...

Merge tag 'for-4.13/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Add the ability to use select or poll /dev/mapper/control to wait for
   events from multiple DM devices.

 - Convert DM's printk macros over to using pr_<level> macros.

 - Add a big-endian variant of plain64 IV to dm-crypt.

 - Add support for zoned (aka SMR) devices to DM core. DM kcopyd was
   also improved to provide a sequential write feature needed by zoned
   devices.

 - Introduce DM zoned target that provides support for host-managed
   zoned devices, the result dm-zoned device acts as a drive-managed
   interface to the underlying host-managed device.

 - A DM raid fix to avoid using BUG() for error handling.

* tag 'for-4.13/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm zoned: fix overflow when converting zone ID to sectors
  dm raid: stop using BUG() in __rdev_sectors()
  dm zoned: drive-managed zoned block device target
  dm kcopyd: add sequential write feature
  dm linear: add support for zoned block devices
  dm flakey: add support for zoned block devices
  dm: introduce dm_remap_zone_report()
  dm: fix REQ_OP_ZONE_REPORT bio handling
  dm: fix REQ_OP_ZONE_RESET bio handling
  dm table: add zoned block devices validation
  dm: convert DM printk macros to pr_<level> macros
  dm crypt: add big-endian variant of plain64 IV
  dm bio prison: use rb_entry() rather than container_of()
  dm ioctl: report event number in DM_LIST_DEVICES
  dm ioctl: add a new DM_DEV_ARM_POLL ioctl
  dm: add basic support for using the select or poll function

Documentation/device-mapper/dm-zoned.txt

+dm-zoned
+========
+
+The dm-zoned device mapper target exposes a zoned block device (ZBC and
+ZAC compliant devices) as a regular block device without any write
+pattern constraints. In effect, it implements a drive-managed zoned
+block device which hides from the user (a file system or an application
+doing raw block device accesses) the sequential write constraints of
+host-managed zoned block devices and can mitigate the potential
+device-side performance degradation due to excessive random writes on
+host-aware zoned block devices.
+
+For a more detailed description of the zoned block device models and
+their constraints see (for SCSI devices):
+
+http://www.t10.org/drafts.htm#ZBC_Family
+
+and (for ATA devices):
+
+http://www.t13.org/Documents/UploadedDocuments/docs2015/di537r05-Zoned_Device_ATA_Command_Set_ZAC.pdf
+
+The dm-zoned implementation is simple and minimizes system overhead (CPU
+and memory usage as well as storage capacity loss). For a 10TB
+host-managed disk with 256 MB zones, dm-zoned memory usage per disk
+instance is at most 4.5 MB and as little as 5 zones will be used
+internally for storing metadata and performaing reclaim operations.
+
+dm-zoned target devices are formatted and checked using the dmzadm
+utility available at:
+
+https://github.com/hgst/dm-zoned-tools
+
+Algorithm
+=========
+
+dm-zoned implements an on-disk buffering scheme to handle non-sequential
+write accesses to the sequential zones of a zoned block device.
+Conventional zones are used for caching as well as for storing internal
+metadata.
+
+The zones of the device are separated into 2 types:
+
+1) Metadata zones: these are conventional zones used to store metadata.
+Metadata zones are not reported as useable capacity to the user.
+
+2) Data zones: all remaining zones, the vast majority of which will be
+sequential zones used exclusively to store user data. The conventional
+zones of the device may be used also for buffering user random writes.
+Data in these zones may be directly mapped to the conventional zone, but
+later moved to a sequential zone so that the conventional zone can be
+reused for buffering incoming random writes.
+
+dm-zoned exposes a logical device with a sector size of 4096 bytes,
+irrespective of the physical sector size of the backend zoned block
+device being used. This allows reducing the amount of metadata needed to
+manage valid blocks (blocks written).
+
+The on-disk metadata format is as follows:
+
+1) The first block of the first conventional zone found contains the
+super block which describes the on disk amount and position of metadata
+blocks.
+
+2) Following the super block, a set of blocks is used to describe the
+mapping of the logical device blocks. The mapping is done per chunk of
+blocks, with the chunk size equal to the zoned block device size. The
+mapping table is indexed by chunk number and each mapping entry
+indicates the zone number of the device storing the chunk of data. Each
+mapping entry may also indicate if the zone number of a conventional
+zone used to buffer random modification to the data zone.
+
+3) A set of blocks used to store bitmaps indicating the validity of
+blocks in the data zones follows the mapping table. A valid block is
+defined as a block that was written and not discarded. For a buffered
+data chunk, a block is always valid only in the data zone mapping the
+chunk or in the buffer zone of the chunk.
+
+For a logical chunk mapped to a conventional zone, all write operations
+are processed by directly writing to the zone. If the mapping zone is a
+sequential zone, the write operation is processed directly only if the
+write offset within the logical chunk is equal to the write pointer
+offset within of the sequential data zone (i.e. the write operation is
+aligned on the zone write pointer). Otherwise, write operations are
+processed indirectly using a buffer zone. In that case, an unused
+conventional zone is allocated and assigned to the chunk being
+accessed. Writing a block to the buffer zone of a chunk will
+automatically invalidate the same block in the sequential zone mapping
+the chunk. If all blocks of the sequential zone become invalid, the zone
+is freed and the chunk buffer zone becomes the primary zone mapping the
+chunk, resulting in native random write performance similar to a regular
+block device.
+
+Read operations are processed according to the block validity
+information provided by the bitmaps. Valid blocks are read either from
+the sequential zone mapping a chunk, or if the chunk is buffered, from
+the buffer zone assigned. If the accessed chunk has no mapping, or the
+accessed blocks are invalid, the read buffer is zeroed and the read
+operation terminated.
+
+After some time, the limited number of convnetional zones available may
+be exhausted (all used to map chunks or buffer sequential zones) and
+unaligned writes to unbuffered chunks become impossible. To avoid this
+situation, a reclaim process regularly scans used conventional zones and
+tries to reclaim the least recently used zones by copying the valid
+blocks of the buffer zone to a free sequential zone. Once the copy
+completes, the chunk mapping is updated to point to the sequential zone
+and the buffer zone freed for reuse.
+
+Metadata Protection
+===================
+
+To protect metadata against corruption in case of sudden power loss or
+system crash, 2 sets of metadata zones are used. One set, the primary
+set, is used as the main metadata region, while the secondary set is
+used as a staging area. Modified metadata is first written to the
+secondary set and validated by updating the super block in the secondary
+set, a generation counter is used to indicate that this set contains the
+newest metadata. Once this operation completes, in place of metadata
+block updates can be done in the primary metadata set. This ensures that
+one of the set is always consistent (all modifications committed or none
+at all). Flush operations are used as a commit point. Upon reception of
+a flush request, metadata modification activity is temporarily blocked
+(for both incoming BIO processing and reclaim process) and all dirty
+metadata blocks are staged and updated. Normal operation is then
+resumed. Flushing metadata thus only temporarily delays write and
+discard requests. Read requests can be processed concurrently while
+metadata flush is being executed.
+
+Usage
+=====
+
+A zoned block device must first be formatted using the dmzadm tool. This
+will analyze the device zone configuration, determine where to place the
+metadata sets on the device and initialize the metadata sets.
+
+Ex:
+
+dmzadm --format /dev/sdxx
+
+For a formatted device, the target can be created normally with the
+dmsetup utility. The only parameter that dm-zoned requires is the
+underlying zoned block device name. Ex:
+
+echo "0 `blockdev --getsize ${dev}` zoned ${dev}" | dmsetup create dmz-`basename ${dev}`

drivers/md/Kconfig

@@ -521,6 +521,23 @@ config DM_INTEGRITY
 	  To compile this code as a module, choose M here: the module will
 	  be called dm-integrity.
 
+config DM_ZONED
+	tristate "Drive-managed zoned block device target support"
+	depends on BLK_DEV_DM
+	depends on BLK_DEV_ZONED
+	---help---
+	  This device-mapper target takes a host-managed or host-aware zoned
+	  block device and exposes most of its capacity as a regular block
+	  device (drive-managed zoned block device) without any write
+	  constraints. This is mainly intended for use with file systems that
+	  do not natively support zoned block devices but still want to
+	  benefit from the increased capacity offered by SMR disks. Other uses
+	  by applications using raw block devices (for example object stores)
+	  are also possible.
+
+	  To compile this code as a module, choose M here: the module will
+	  be called dm-zoned.
+
 	  If unsure, say N.
 
 endif # MD

drivers/md/Makefile

@@ -20,6 +20,7 @@ dm-era-y	+= dm-era-target.o
 dm-verity-y	+= dm-verity-target.o
 md-mod-y	+= md.o bitmap.o
 raid456-y	+= raid5.o raid5-cache.o raid5-ppl.o
+dm-zoned-y	+= dm-zoned-target.o dm-zoned-metadata.o dm-zoned-reclaim.o
 
 # Note: link order is important.  All raid personalities
 # and must come before md.o, as they each initialise 
@@ -60,6 +61,7 @@ obj-$(CONFIG_DM_CACHE_SMQ)	+= dm-cache-smq.o
 obj-$(CONFIG_DM_ERA)		+= dm-era.o
 obj-$(CONFIG_DM_LOG_WRITES)	+= dm-log-writes.o
 obj-$(CONFIG_DM_INTEGRITY)	+= dm-integrity.o
+obj-$(CONFIG_DM_ZONED)		+= dm-zoned.o
 
 ifeq ($(CONFIG_DM_UEVENT),y)
 dm-mod-objs			+= dm-uevent.o

drivers/md/dm-bio-prison-v1.c

@@ -116,7 +116,7 @@ static int __bio_detain(struct dm_bio_prison *prison,
 
 	while (*new) {
 		struct dm_bio_prison_cell *cell =
-			container_of(*new, struct dm_bio_prison_cell, node);
+			rb_entry(*new, struct dm_bio_prison_cell, node);
 
 		r = cmp_keys(key, &cell->key);
 

drivers/md/dm-bio-prison-v2.c

@@ -120,7 +120,7 @@ static bool __find_or_insert(struct dm_bio_prison_v2 *prison,
 
 	while (*new) {
 		struct dm_bio_prison_cell_v2 *cell =
-			container_of(*new, struct dm_bio_prison_cell_v2, node);
+			rb_entry(*new, struct dm_bio_prison_cell_v2, node);
 
 		r = cmp_keys(key, &cell->key);
 

drivers/md/dm-core.h

@@ -147,4 +147,7 @@ static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen
 	return !maxlen || strlen(result) + 1 >= maxlen;
 }
 
+extern atomic_t dm_global_event_nr;
+extern wait_queue_head_t dm_global_eventq;
+
 #endif

drivers/md/dm-crypt.c

@@ -246,6 +246,9 @@ static struct crypto_aead *any_tfm_aead(struct crypt_config *cc)
  * plain64: the initial vector is the 64-bit little-endian version of the sector
  *        number, padded with zeros if necessary.
  *
+ * plain64be: the initial vector is the 64-bit big-endian version of the sector
+ *        number, padded with zeros if necessary.
+ *
  * essiv: "encrypted sector|salt initial vector", the sector number is
  *        encrypted with the bulk cipher using a salt as key. The salt
  *        should be derived from the bulk cipher's key via hashing.
@@ -302,6 +305,16 @@ static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
 	return 0;
 }
 
+static int crypt_iv_plain64be_gen(struct crypt_config *cc, u8 *iv,
+				  struct dm_crypt_request *dmreq)
+{
+	memset(iv, 0, cc->iv_size);
+	/* iv_size is at least of size u64; usually it is 16 bytes */
+	*(__be64 *)&iv[cc->iv_size - sizeof(u64)] = cpu_to_be64(dmreq->iv_sector);
+
+	return 0;
+}
+
 /* Initialise ESSIV - compute salt but no local memory allocations */
 static int crypt_iv_essiv_init(struct crypt_config *cc)
 {
@@ -835,6 +848,10 @@ static const struct crypt_iv_operations crypt_iv_plain64_ops = {
 	.generator = crypt_iv_plain64_gen
 };
 
+static const struct crypt_iv_operations crypt_iv_plain64be_ops = {
+	.generator = crypt_iv_plain64be_gen
+};
+
 static const struct crypt_iv_operations crypt_iv_essiv_ops = {
 	.ctr       = crypt_iv_essiv_ctr,
 	.dtr       = crypt_iv_essiv_dtr,
@@ -2208,6 +2225,8 @@ static int crypt_ctr_ivmode(struct dm_target *ti, const char *ivmode)
 		cc->iv_gen_ops = &crypt_iv_plain_ops;
 	else if (strcmp(ivmode, "plain64") == 0)
 		cc->iv_gen_ops = &crypt_iv_plain64_ops;
+	else if (strcmp(ivmode, "plain64be") == 0)
+		cc->iv_gen_ops = &crypt_iv_plain64be_ops;
 	else if (strcmp(ivmode, "essiv") == 0)
 		cc->iv_gen_ops = &crypt_iv_essiv_ops;
 	else if (strcmp(ivmode, "benbi") == 0)
@@ -2987,7 +3006,7 @@ static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
 
 static struct target_type crypt_target = {
 	.name   = "crypt",
-	.version = {1, 17, 0},
+	.version = {1, 18, 0},
 	.module = THIS_MODULE,
 	.ctr    = crypt_ctr,
 	.dtr    = crypt_dtr,

drivers/md/dm-flakey.c

@@ -275,7 +275,7 @@ static void flakey_map_bio(struct dm_target *ti, struct bio *bio)
 	struct flakey_c *fc = ti->private;
 
 	bio->bi_bdev = fc->dev->bdev;
-	if (bio_sectors(bio))
+	if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET)
 		bio->bi_iter.bi_sector =
 			flakey_map_sector(ti, bio->bi_iter.bi_sector);
 }
@@ -306,6 +306,14 @@ static int flakey_map(struct dm_target *ti, struct bio *bio)
 	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
 	pb->bio_submitted = false;
 
+	/* Do not fail reset zone */
+	if (bio_op(bio) == REQ_OP_ZONE_RESET)
+		goto map_bio;
+
+	/* We need to remap reported zones, so remember the BIO iter */
+	if (bio_op(bio) == REQ_OP_ZONE_REPORT)
+		goto map_bio;
+
 	/* Are we alive ? */
 	elapsed = (jiffies - fc->start_time) / HZ;
 	if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
@@ -359,11 +367,19 @@ static int flakey_map(struct dm_target *ti, struct bio *bio)
 }
 
 static int flakey_end_io(struct dm_target *ti, struct bio *bio,
-		blk_status_t *error)
+			 blk_status_t *error)
 {
 	struct flakey_c *fc = ti->private;
 	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
 
+	if (bio_op(bio) == REQ_OP_ZONE_RESET)
+		return DM_ENDIO_DONE;
+
+	if (bio_op(bio) == REQ_OP_ZONE_REPORT) {
+		dm_remap_zone_report(ti, bio, fc->start);
+		return DM_ENDIO_DONE;
+	}
+
 	if (!*error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
 		if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) &&
 		    all_corrupt_bio_flags_match(bio, fc)) {
@@ -446,7 +462,8 @@ static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_
 
 static struct target_type flakey_target = {
 	.name   = "flakey",
-	.version = {1, 4, 0},
+	.version = {1, 5, 0},
+	.features = DM_TARGET_ZONED_HM,
 	.module = THIS_MODULE,
 	.ctr    = flakey_ctr,
 	.dtr    = flakey_dtr,

drivers/md/dm-ioctl.c

@@ -23,6 +23,14 @@
 #define DM_MSG_PREFIX "ioctl"
 #define DM_DRIVER_EMAIL "dm-devel@redhat.com"
 
+struct dm_file {
+	/*
+	 * poll will wait until the global event number is greater than
+	 * this value.
+	 */
+	volatile unsigned global_event_nr;
+};
+
 /*-----------------------------------------------------------------
  * The ioctl interface needs to be able to look up devices by
  * name or uuid.
@@ -456,9 +464,9 @@ void dm_deferred_remove(void)
  * All the ioctl commands get dispatched to functions with this
  * prototype.
  */
-typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
+typedef int (*ioctl_fn)(struct file *filp, struct dm_ioctl *param, size_t param_size);
 
-static int remove_all(struct dm_ioctl *param, size_t param_size)
+static int remove_all(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	dm_hash_remove_all(true, !!(param->flags & DM_DEFERRED_REMOVE), false);
 	param->data_size = 0;
@@ -491,13 +499,14 @@ static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
 	return ((void *) param) + param->data_start;
 }
 
-static int list_devices(struct dm_ioctl *param, size_t param_size)
+static int list_devices(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	unsigned int i;
 	struct hash_cell *hc;
 	size_t len, needed = 0;
 	struct gendisk *disk;
 	struct dm_name_list *nl, *old_nl = NULL;
+	uint32_t *event_nr;
 
 	down_write(&_hash_lock);
 
@@ -510,6 +519,7 @@ static int list_devices(struct dm_ioctl *param, size_t param_size)
 			needed += sizeof(struct dm_name_list);
 			needed += strlen(hc->name) + 1;
 			needed += ALIGN_MASK;
+			needed += (sizeof(uint32_t) + ALIGN_MASK) & ~ALIGN_MASK;
 		}
 	}
 
@@ -539,7 +549,9 @@ static int list_devices(struct dm_ioctl *param, size_t param_size)
 			strcpy(nl->name, hc->name);
 
 			old_nl = nl;
-			nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
+			event_nr = align_ptr(((void *) (nl + 1)) + strlen(hc->name) + 1);
+			*event_nr = dm_get_event_nr(hc->md);
+			nl = align_ptr(event_nr + 1);
 		}
 	}
 
@@ -582,7 +594,7 @@ static void list_version_get_info(struct target_type *tt, void *param)
     info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
 }
 
-static int list_versions(struct dm_ioctl *param, size_t param_size)
+static int list_versions(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	size_t len, needed = 0;
 	struct dm_target_versions *vers;
@@ -724,7 +736,7 @@ static void __dev_status(struct mapped_device *md, struct dm_ioctl *param)
 	}
 }
 
-static int dev_create(struct dm_ioctl *param, size_t param_size)
+static int dev_create(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	int r, m = DM_ANY_MINOR;
 	struct mapped_device *md;
@@ -816,7 +828,7 @@ static struct mapped_device *find_device(struct dm_ioctl *param)
 	return md;
 }
 
-static int dev_remove(struct dm_ioctl *param, size_t param_size)
+static int dev_remove(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	struct hash_cell *hc;
 	struct mapped_device *md;
@@ -881,7 +893,7 @@ static int invalid_str(char *str, void *end)
 	return -EINVAL;
 }
 
-static int dev_rename(struct dm_ioctl *param, size_t param_size)
+static int dev_rename(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	int r;
 	char *new_data = (char *) param + param->data_start;
@@ -911,7 +923,7 @@ static int dev_rename(struct dm_ioctl *param, size_t param_size)
 	return 0;
 }
 
-static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
+static int dev_set_geometry(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	int r = -EINVAL, x;
 	struct mapped_device *md;
@@ -1060,7 +1072,7 @@ static int do_resume(struct dm_ioctl *param)
  * Set or unset the suspension state of a device.
  * If the device already is in the requested state we just return its status.
  */
-static int dev_suspend(struct dm_ioctl *param, size_t param_size)
+static int dev_suspend(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	if (param->flags & DM_SUSPEND_FLAG)
 		return do_suspend(param);
@@ -1072,7 +1084,7 @@ static int dev_suspend(struct dm_ioctl *param, size_t param_size)
  * Copies device info back to user space, used by
  * the create and info ioctls.
  */
-static int dev_status(struct dm_ioctl *param, size_t param_size)
+static int dev_status(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	struct mapped_device *md;
 
@@ -1163,7 +1175,7 @@ static void retrieve_status(struct dm_table *table,
 /*
  * Wait for a device to report an event
  */
-static int dev_wait(struct dm_ioctl *param, size_t param_size)
+static int dev_wait(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	int r = 0;
 	struct mapped_device *md;
@@ -1200,6 +1212,19 @@ static int dev_wait(struct dm_ioctl *param, size_t param_size)
 	return r;
 }
 
+/*
+ * Remember the global event number and make it possible to poll
+ * for further events.
+ */
+static int dev_arm_poll(struct file *filp, struct dm_ioctl *param, size_t param_size)
+{
+	struct dm_file *priv = filp->private_data;
+
+	priv->global_event_nr = atomic_read(&dm_global_event_nr);
+
+	return 0;
+}
+
 static inline fmode_t get_mode(struct dm_ioctl *param)
 {
 	fmode_t mode = FMODE_READ | FMODE_WRITE;
@@ -1269,7 +1294,7 @@ static bool is_valid_type(enum dm_queue_mode cur, enum dm_queue_mode new)
 	return false;
 }
 
-static int table_load(struct dm_ioctl *param, size_t param_size)
+static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	int r;
 	struct hash_cell *hc;
@@ -1356,7 +1381,7 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
 	return r;
 }
 
-static int table_clear(struct dm_ioctl *param, size_t param_size)
+static int table_clear(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	struct hash_cell *hc;
 	struct mapped_device *md;
@@ -1430,7 +1455,7 @@ static void retrieve_deps(struct dm_table *table,
 	param->data_size = param->data_start + needed;
 }
 
-static int table_deps(struct dm_ioctl *param, size_t param_size)
+static int table_deps(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	struct mapped_device *md;
 	struct dm_table *table;
@@ -1456,7 +1481,7 @@ static int table_deps(struct dm_ioctl *param, size_t param_size)
  * Return the status of a device as a text string for each
  * target.
  */
-static int table_status(struct dm_ioctl *param, size_t param_size)
+static int table_status(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	struct mapped_device *md;
 	struct dm_table *table;
@@ -1511,7 +1536,7 @@ static int message_for_md(struct mapped_device *md, unsigned argc, char **argv,
 /*
  * Pass a message to the target that's at the supplied device offset.
  */
-static int target_message(struct dm_ioctl *param, size_t param_size)
+static int target_message(struct file *filp, struct dm_ioctl *param, size_t param_size)
 {
 	int r, argc;
 	char **argv;
@@ -1628,7 +1653,8 @@ static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags)
 		{DM_LIST_VERSIONS_CMD, 0, list_versions},
 
 		{DM_TARGET_MSG_CMD, 0, target_message},
-		{DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry}
+		{DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry},
+		{DM_DEV_ARM_POLL, IOCTL_FLAGS_NO_PARAMS, dev_arm_poll},
 	};
 
 	if (unlikely(cmd >= ARRAY_SIZE(_ioctls)))
@@ -1783,7 +1809,7 @@ static int validate_params(uint cmd, struct dm_ioctl *param)
 	return 0;
 }
 
-static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
+static int ctl_ioctl(struct file *file, uint command, struct dm_ioctl __user *user)
 {
 	int r = 0;
 	int ioctl_flags;
@@ -1837,7 +1863,7 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
 		goto out;
 
 	param->data_size = offsetof(struct dm_ioctl, data);
-	r = fn(param, input_param_size);
+	r = fn(file, param, input_param_size);
 
 	if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) &&
 	    unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS))
@@ -1856,7 +1882,7 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
 
 static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
 {
-	return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u);
+	return (long)ctl_ioctl(file, command, (struct dm_ioctl __user *)u);
 }
 
 #ifdef CONFIG_COMPAT
@@ -1868,8 +1894,47 @@ static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u)
 #define dm_compat_ctl_ioctl NULL
 #endif
 
+static int dm_open(struct inode *inode, struct file *filp)
+{
+	int r;
+	struct dm_file *priv;
+
+	r = nonseekable_open(inode, filp);
+	if (unlikely(r))
+		return r;
+
+	priv = filp->private_data = kmalloc(sizeof(struct dm_file), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->global_event_nr = atomic_read(&dm_global_event_nr);
+
+	return 0;
+}
+
+static int dm_release(struct inode *inode, struct file *filp)
+{
+	kfree(filp->private_data);
+	return 0;
+}
+
+static unsigned dm_poll(struct file *filp, poll_table *wait)
+{
+	struct dm_file *priv = filp->private_data;
+	unsigned mask = 0;
+
+	poll_wait(filp, &dm_global_eventq, wait);
+
+	if ((int)(atomic_read(&dm_global_event_nr) - priv->global_event_nr) > 0)
+		mask |= POLLIN;
+
+	return mask;
+}
+
 static const struct file_operations _ctl_fops = {
-	.open = nonseekable_open,
+	.open    = dm_open,
+	.release = dm_release,
+	.poll    = dm_poll,
 	.unlocked_ioctl	 = dm_ctl_ioctl,
 	.compat_ioctl = dm_compat_ctl_ioctl,
 	.owner	 = THIS_MODULE,

drivers/md/dm-kcopyd.c

@@ -356,6 +356,7 @@ struct kcopyd_job {
 	struct mutex lock;
 	atomic_t sub_jobs;
 	sector_t progress;
+	sector_t write_offset;
 
 	struct kcopyd_job *master_job;
 };
@@ -386,6 +387,31 @@ void dm_kcopyd_exit(void)
  * Functions to push and pop a job onto the head of a given job
  * list.
  */
+static struct kcopyd_job *pop_io_job(struct list_head *jobs,
+				     struct dm_kcopyd_client *kc)
+{
+	struct kcopyd_job *job;
+
+	/*
+	 * For I/O jobs, pop any read, any write without sequential write
+	 * constraint and sequential writes that are at the right position.
+	 */
+	list_for_each_entry(job, jobs, list) {
+		if (job->rw == READ || !test_bit(DM_KCOPYD_WRITE_SEQ, &job->flags)) {
+			list_del(&job->list);
+			return job;
+		}
+
+		if (job->write_offset == job->master_job->write_offset) {
+			job->master_job->write_offset += job->source.count;
+			list_del(&job->list);
+			return job;
+		}
+	}
+
+	return NULL;
+}
+
 static struct kcopyd_job *pop(struct list_head *jobs,
 			      struct dm_kcopyd_client *kc)
 {
@@ -395,8 +421,12 @@ static struct kcopyd_job *pop(struct list_head *jobs,
 	spin_lock_irqsave(&kc->job_lock, flags);
 
 	if (!list_empty(jobs)) {
-		job = list_entry(jobs->next, struct kcopyd_job, list);
-		list_del(&job->list);
+		if (jobs == &kc->io_jobs)
+			job = pop_io_job(jobs, kc);
+		else {
+			job = list_entry(jobs->next, struct kcopyd_job, list);
+			list_del(&job->list);
+		}
 	}
 	spin_unlock_irqrestore(&kc->job_lock, flags);
 
@@ -506,6 +536,14 @@ static int run_io_job(struct kcopyd_job *job)
 		.client = job->kc->io_client,
 	};
 
+	/*
+	 * If we need to write sequentially and some reads or writes failed,
+	 * no point in continuing.
+	 */
+	if (test_bit(DM_KCOPYD_WRITE_SEQ, &job->flags) &&
+	    job->master_job->write_err)
+		return -EIO;
+
 	io_job_start(job->kc->throttle);
 
 	if (job->rw == READ)
@@ -655,6 +693,7 @@ static void segment_complete(int read_err, unsigned long write_err,
 		int i;
 
 		*sub_job = *job;
+		sub_job->write_offset = progress;
 		sub_job->source.sector += progress;
 		sub_job->source.count = count;
 
@@ -723,6 +762,27 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
 	job->num_dests = num_dests;
 	memcpy(&job->dests, dests, sizeof(*dests) * num_dests);
 
+	/*
+	 * If one of the destination is a host-managed zoned block device,
+	 * we need to write sequentially. If one of the destination is a
+	 * host-aware device, then leave it to the caller to choose what to do.
+	 */
+	if (!test_bit(DM_KCOPYD_WRITE_SEQ, &job->flags)) {
+		for (i = 0; i < job->num_dests; i++) {
+			if (bdev_zoned_model(dests[i].bdev) == BLK_ZONED_HM) {
+				set_bit(DM_KCOPYD_WRITE_SEQ, &job->flags);
+				break;
+			}
+		}
+	}
+
+	/*
+	 * If we need to write sequentially, errors cannot be ignored.
+	 */
+	if (test_bit(DM_KCOPYD_WRITE_SEQ, &job->flags) &&
+	    test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags))
+		clear_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags);
+
 	if (from) {
 		job->source = *from;
 		job->pages = NULL;
@@ -746,6 +806,7 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
 	job->fn = fn;
 	job->context = context;
 	job->master_job = job;
+	job->write_offset = 0;
 
 	if (job->source.count <= SUB_JOB_SIZE)
 		dispatch_job(job);

drivers/md/dm-linear.c

@@ -89,7 +89,7 @@ static void linear_map_bio(struct dm_target *ti, struct bio *bio)
 	struct linear_c *lc = ti->private;
 
 	bio->bi_bdev = lc->dev->bdev;
-	if (bio_sectors(bio))
+	if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET)
 		bio->bi_iter.bi_sector =
 			linear_map_sector(ti, bio->bi_iter.bi_sector);
 }
@@ -101,6 +101,17 @@ static int linear_map(struct dm_target *ti, struct bio *bio)
 	return DM_MAPIO_REMAPPED;
 }
 
+static int linear_end_io(struct dm_target *ti, struct bio *bio,
+			 blk_status_t *error)
+{
+	struct linear_c *lc = ti->private;
+
+	if (!*error && bio_op(bio) == REQ_OP_ZONE_REPORT)
+		dm_remap_zone_report(ti, bio, lc->start);
+
+	return DM_ENDIO_DONE;
+}
+
 static void linear_status(struct dm_target *ti, status_type_t type,
 			  unsigned status_flags, char *result, unsigned maxlen)
 {
@@ -161,12 +172,13 @@ static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
 
 static struct target_type linear_target = {
 	.name   = "linear",
-	.version = {1, 3, 0},
-	.features = DM_TARGET_PASSES_INTEGRITY,
+	.version = {1, 4, 0},
+	.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM,
 	.module = THIS_MODULE,
 	.ctr    = linear_ctr,
 	.dtr    = linear_dtr,
 	.map    = linear_map,
+	.end_io = linear_end_io,
 	.status = linear_status,
 	.prepare_ioctl = linear_prepare_ioctl,
 	.iterate_devices = linear_iterate_devices,

drivers/md/dm-raid.c

@@ -1571,7 +1571,7 @@ static sector_t __rdev_sectors(struct raid_set *rs)
 			return rdev->sectors;
 	}
 
-	BUG(); /* Constructor ensures we got some. */
+	return 0;
 }
 
 /* Calculate the sectors per device and per array used for @rs */
@@ -2941,7 +2941,7 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	bool resize;
 	struct raid_type *rt;
 	unsigned int num_raid_params, num_raid_devs;
-	sector_t calculated_dev_sectors;
+	sector_t calculated_dev_sectors, rdev_sectors;
 	struct raid_set *rs = NULL;
 	const char *arg;
 	struct rs_layout rs_layout;
@@ -3017,7 +3017,14 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	if (r)
 		goto bad;
 
-	resize = calculated_dev_sectors != __rdev_sectors(rs);
+	rdev_sectors = __rdev_sectors(rs);
+	if (!rdev_sectors) {
+		ti->error = "Invalid rdev size";
+		r = -EINVAL;
+		goto bad;
+	}
+
+	resize = calculated_dev_sectors != rdev_sectors;
 
 	INIT_WORK(&rs->md.event_work, do_table_event);
 	ti->private = rs;

drivers/md/dm-table.c

@@ -319,6 +319,39 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 		return 1;
 	}
 
+	/*
+	 * 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) {
+		unsigned int zone_sectors = bdev_zone_sectors(bdev);
+
+		if (start & (zone_sectors - 1)) {
+			DMWARN("%s: start=%llu not aligned to h/w zone size %u of %s",
+			       dm_device_name(ti->table->md),
+			       (unsigned long long)start,
+			       zone_sectors, bdevname(bdev, b));
+			return 1;
+		}
+
+		/*
+		 * Note: The last zone of a zoned block device may be smaller
+		 * than other zones. So for a target mapping the end of a
+		 * zoned block device with such a zone, len would not be zone
+		 * aligned. We do not allow such last smaller zone to be part
+		 * of the mapping here to ensure that mappings with multiple
+		 * devices do not end up with a smaller zone in the middle of
+		 * the sector range.
+		 */
+		if (len & (zone_sectors - 1)) {
+			DMWARN("%s: len=%llu not aligned to h/w zone size %u of %s",
+			       dm_device_name(ti->table->md),
+			       (unsigned long long)len,
+			       zone_sectors, bdevname(bdev, b));
+			return 1;
+		}
+	}
+
 	if (logical_block_size_sectors <= 1)
 		return 0;
 
@@ -456,6 +489,8 @@ static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 		       q->limits.alignment_offset,
 		       (unsigned long long) start << SECTOR_SHIFT);
 
+	limits->zoned = blk_queue_zoned_model(q);
+
 	return 0;
 }
 
@@ -1346,6 +1381,88 @@ bool dm_table_has_no_data_devices(struct dm_table *table)
 	return true;
 }
 
+static int device_is_zoned_model(struct dm_target *ti, struct dm_dev *dev,
+				 sector_t start, sector_t len, void *data)
+{
+	struct request_queue *q = bdev_get_queue(dev->bdev);
+	enum blk_zoned_model *zoned_model = data;
+
+	return q && blk_queue_zoned_model(q) == *zoned_model;
+}
+
+static bool dm_table_supports_zoned_model(struct dm_table *t,
+					  enum blk_zoned_model zoned_model)
+{
+	struct dm_target *ti;
+	unsigned i;
+
+	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+		ti = dm_table_get_target(t, i);
+
+		if (zoned_model == BLK_ZONED_HM &&
+		    !dm_target_supports_zoned_hm(ti->type))
+			return false;
+
+		if (!ti->type->iterate_devices ||
+		    !ti->type->iterate_devices(ti, device_is_zoned_model, &zoned_model))
+			return false;
+	}
+
+	return true;
+}
+
+static int device_matches_zone_sectors(struct dm_target *ti, struct dm_dev *dev,
+				       sector_t start, sector_t len, void *data)
+{
+	struct request_queue *q = bdev_get_queue(dev->bdev);
+	unsigned int *zone_sectors = data;
+
+	return q && blk_queue_zone_sectors(q) == *zone_sectors;
+}
+
+static bool dm_table_matches_zone_sectors(struct dm_table *t,
+					  unsigned int zone_sectors)
+{
+	struct dm_target *ti;
+	unsigned i;
+
+	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+		ti = dm_table_get_target(t, i);
+
+		if (!ti->type->iterate_devices ||
+		    !ti->type->iterate_devices(ti, device_matches_zone_sectors, &zone_sectors))
+			return false;
+	}
+
+	return true;
+}
+
+static int validate_hardware_zoned_model(struct dm_table *table,
+					 enum blk_zoned_model zoned_model,
+					 unsigned int zone_sectors)
+{
+	if (zoned_model == BLK_ZONED_NONE)
+		return 0;
+
+	if (!dm_table_supports_zoned_model(table, zoned_model)) {
+		DMERR("%s: zoned model is not consistent across all devices",
+		      dm_device_name(table->md));
+		return -EINVAL;
+	}
+
+	/* Check zone size validity and compatibility */
+	if (!zone_sectors || !is_power_of_2(zone_sectors))
+		return -EINVAL;
+
+	if (!dm_table_matches_zone_sectors(table, zone_sectors)) {
+		DMERR("%s: zone sectors is not consistent across all devices",
+		      dm_device_name(table->md));
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /*
  * Establish the new table's queue_limits and validate them.
  */
@@ -1355,6 +1472,8 @@ int dm_calculate_queue_limits(struct dm_table *table,
 	struct dm_target *ti;
 	struct queue_limits ti_limits;
 	unsigned i;
+	enum blk_zoned_model zoned_model = BLK_ZONED_NONE;
+	unsigned int zone_sectors = 0;
 
 	blk_set_stacking_limits(limits);
 
@@ -1372,6 +1491,15 @@ int dm_calculate_queue_limits(struct dm_table *table,
 		ti->type->iterate_devices(ti, dm_set_device_limits,
 					  &ti_limits);
 
+		if (zoned_model == BLK_ZONED_NONE && ti_limits.zoned != BLK_ZONED_NONE) {
+			/*
+			 * After stacking all limits, validate all devices
+			 * in table support this zoned model and zone sectors.
+			 */
+			zoned_model = ti_limits.zoned;
+			zone_sectors = ti_limits.chunk_sectors;
+		}
+
 		/* Set I/O hints portion of queue limits */
 		if (ti->type->io_hints)
 			ti->type->io_hints(ti, &ti_limits);
@@ -1396,8 +1524,42 @@ int dm_calculate_queue_limits(struct dm_table *table,
 			       dm_device_name(table->md),
 			       (unsigned long long) ti->begin,
 			       (unsigned long long) ti->len);
+
+		/*
+		 * FIXME: this should likely be moved to blk_stack_limits(), would
+		 * also eliminate limits->zoned stacking hack in dm_set_device_limits()
+		 */
+		if (limits->zoned == BLK_ZONED_NONE && ti_limits.zoned != BLK_ZONED_NONE) {
+			/*
+			 * By default, the stacked limits zoned model is set to
+			 * BLK_ZONED_NONE in blk_set_stacking_limits(). Update
+			 * this model using the first target model reported
+			 * that is not BLK_ZONED_NONE. This will be either the
+			 * first target device zoned model or the model reported
+			 * by the target .io_hints.
+			 */
+			limits->zoned = ti_limits.zoned;
+		}
 	}
 
+	/*
+	 * Verify that the zoned model and zone sectors, as determined before
+	 * any .io_hints override, are the same across all devices in the table.
+	 * - this is especially relevant if .io_hints is emulating a disk-managed
+	 *   zoned model (aka BLK_ZONED_NONE) on host-managed zoned block devices.
+	 * BUT...
+	 */
+	if (limits->zoned != BLK_ZONED_NONE) {
+		/*
+		 * ...IF the above limits stacking determined a zoned model
+		 * validate that all of the table's devices conform to it.
+		 */
+		zoned_model = limits->zoned;
+		zone_sectors = limits->chunk_sectors;
+	}
+	if (validate_hardware_zoned_model(table, zoned_model, zone_sectors))
+		return -EINVAL;
+
 	return validate_hardware_logical_block_alignment(table, limits);
 }
 

drivers/md/dm-zoned-reclaim.c

+/*
+ * Copyright (C) 2017 Western Digital Corporation or its affiliates.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-zoned.h"
+
+#include <linux/module.h>
+
+#define	DM_MSG_PREFIX		"zoned reclaim"
+
+struct dmz_reclaim {
+	struct dmz_metadata     *metadata;
+	struct dmz_dev		*dev;
+
+	struct delayed_work	work;
+	struct workqueue_struct *wq;
+
+	struct dm_kcopyd_client	*kc;
+	struct dm_kcopyd_throttle kc_throttle;
+	int			kc_err;
+
+	unsigned long		flags;
+
+	/* Last target access time */
+	unsigned long		atime;
+};
+
+/*
+ * Reclaim state flags.
+ */
+enum {
+	DMZ_RECLAIM_KCOPY,
+};
+
+/*
+ * Number of seconds of target BIO inactivity to consider the target idle.
+ */
+#define DMZ_IDLE_PERIOD		(10UL * HZ)
+
+/*
+ * Percentage of unmapped (free) random zones below which reclaim starts
+ * even if the target is busy.
+ */
+#define DMZ_RECLAIM_LOW_UNMAP_RND	30
+
+/*
+ * Percentage of unmapped (free) random zones above which reclaim will
+ * stop if the target is busy.
+ */
+#define DMZ_RECLAIM_HIGH_UNMAP_RND	50
+
+/*
+ * Align a sequential zone write pointer to chunk_block.
+ */
+static int dmz_reclaim_align_wp(struct dmz_reclaim *zrc, struct dm_zone *zone,
+				sector_t block)
+{
+	struct dmz_metadata *zmd = zrc->metadata;
+	sector_t wp_block = zone->wp_block;
+	unsigned int nr_blocks;
+	int ret;
+
+	if (wp_block == block)
+		return 0;
+
+	if (wp_block > block)
+		return -EIO;
+
+	/*
+	 * Zeroout the space between the write
+	 * pointer and the requested position.
+	 */
+	nr_blocks = block - wp_block;
+	ret = blkdev_issue_zeroout(zrc->dev->bdev,
+				   dmz_start_sect(zmd, zone) + dmz_blk2sect(wp_block),
+				   dmz_blk2sect(nr_blocks), GFP_NOFS, false);
+	if (ret) {
+		dmz_dev_err(zrc->dev,
+			    "Align zone %u wp %llu to %llu (wp+%u) blocks failed %d",
+			    dmz_id(zmd, zone), (unsigned long long)wp_block,
+			    (unsigned long long)block, nr_blocks, ret);
+		return ret;
+	}
+
+	zone->wp_block = block;
+
+	return 0;
+}
+
+/*
+ * dm_kcopyd_copy end notification.
+ */
+static void dmz_reclaim_kcopy_end(int read_err, unsigned long write_err,
+				  void *context)
+{
+	struct dmz_reclaim *zrc = context;
+
+	if (read_err || write_err)
+		zrc->kc_err = -EIO;
+	else
+		zrc->kc_err = 0;
+
+	clear_bit_unlock(DMZ_RECLAIM_KCOPY, &zrc->flags);
+	smp_mb__after_atomic();
+	wake_up_bit(&zrc->flags, DMZ_RECLAIM_KCOPY);
+}
+
+/*
+ * Copy valid blocks of src_zone into dst_zone.
+ */
+static int dmz_reclaim_copy(struct dmz_reclaim *zrc,
+			    struct dm_zone *src_zone, struct dm_zone *dst_zone)
+{
+	struct dmz_metadata *zmd = zrc->metadata;
+	struct dmz_dev *dev = zrc->dev;
+	struct dm_io_region src, dst;
+	sector_t block = 0, end_block;
+	sector_t nr_blocks;
+	sector_t src_zone_block;
+	sector_t dst_zone_block;
+	unsigned long flags = 0;
+	int ret;
+
+	if (dmz_is_seq(src_zone))
+		end_block = src_zone->wp_block;
+	else
+		end_block = dev->zone_nr_blocks;
+	src_zone_block = dmz_start_block(zmd, src_zone);
+	dst_zone_block = dmz_start_block(zmd, dst_zone);
+
+	if (dmz_is_seq(dst_zone))
+		set_bit(DM_KCOPYD_WRITE_SEQ, &flags);
+
+	while (block < end_block) {
+		/* Get a valid region from the source zone */
+		ret = dmz_first_valid_block(zmd, src_zone, &block);
+		if (ret <= 0)
+			return ret;
+		nr_blocks = ret;
+
+		/*
+		 * If we are writing in a sequential zone, we must make sure
+		 * that writes are sequential. So Zeroout any eventual hole
+		 * between writes.
+		 */
+		if (dmz_is_seq(dst_zone)) {
+			ret = dmz_reclaim_align_wp(zrc, dst_zone, block);
+			if (ret)
+				return ret;
+		}
+
+		src.bdev = dev->bdev;
+		src.sector = dmz_blk2sect(src_zone_block + block);
+		src.count = dmz_blk2sect(nr_blocks);
+
+		dst.bdev = dev->bdev;
+		dst.sector = dmz_blk2sect(dst_zone_block + block);
+		dst.count = src.count;
+
+		/* Copy the valid region */
+		set_bit(DMZ_RECLAIM_KCOPY, &zrc->flags);
+		ret = dm_kcopyd_copy(zrc->kc, &src, 1, &dst, flags,
+				     dmz_reclaim_kcopy_end, zrc);
+		if (ret)
+			return ret;
+
+		/* Wait for copy to complete */
+		wait_on_bit_io(&zrc->flags, DMZ_RECLAIM_KCOPY,
+			       TASK_UNINTERRUPTIBLE);
+		if (zrc->kc_err)
+			return zrc->kc_err;
+
+		block += nr_blocks;
+		if (dmz_is_seq(dst_zone))
+			dst_zone->wp_block = block;
+	}
+
+	return 0;
+}
+
+/*
+ * Move valid blocks of dzone buffer zone into dzone (after its write pointer)
+ * and free the buffer zone.
+ */
+static int dmz_reclaim_buf(struct dmz_reclaim *zrc, struct dm_zone *dzone)
+{
+	struct dm_zone *bzone = dzone->bzone;
+	sector_t chunk_block = dzone->wp_block;
+	struct dmz_metadata *zmd = zrc->metadata;
+	int ret;
+
+	dmz_dev_debug(zrc->dev,
+		      "Chunk %u, move buf zone %u (weight %u) to data zone %u (weight %u)",
+		      dzone->chunk, dmz_id(zmd, bzone), dmz_weight(bzone),
+		      dmz_id(zmd, dzone), dmz_weight(dzone));
+
+	/* Flush data zone into the buffer zone */
+	ret = dmz_reclaim_copy(zrc, bzone, dzone);
+	if (ret < 0)
+		return ret;
+
+	dmz_lock_flush(zmd);
+
+	/* Validate copied blocks */
+	ret = dmz_merge_valid_blocks(zmd, bzone, dzone, chunk_block);
+	if (ret == 0) {
+		/* Free the buffer zone */
+		dmz_invalidate_blocks(zmd, bzone, 0, zrc->dev->zone_nr_blocks);
+		dmz_lock_map(zmd);
+		dmz_unmap_zone(zmd, bzone);
+		dmz_unlock_zone_reclaim(dzone);
+		dmz_free_zone(zmd, bzone);
+		dmz_unlock_map(zmd);
+	}
+
+	dmz_unlock_flush(zmd);
+
+	return 0;
+}
+
+/*
+ * Merge valid blocks of dzone into its buffer zone and free dzone.
+ */
+static int dmz_reclaim_seq_data(struct dmz_reclaim *zrc, struct dm_zone *dzone)
+{
+	unsigned int chunk = dzone->chunk;
+	struct dm_zone *bzone = dzone->bzone;
+	struct dmz_metadata *zmd = zrc->metadata;
+	int ret = 0;
+
+	dmz_dev_debug(zrc->dev,
+		      "Chunk %u, move data zone %u (weight %u) to buf zone %u (weight %u)",
+		      chunk, dmz_id(zmd, dzone), dmz_weight(dzone),
+		      dmz_id(zmd, bzone), dmz_weight(bzone));
+
+	/* Flush data zone into the buffer zone */
+	ret = dmz_reclaim_copy(zrc, dzone, bzone);
+	if (ret < 0)
+		return ret;
+
+	dmz_lock_flush(zmd);
+
+	/* Validate copied blocks */
+	ret = dmz_merge_valid_blocks(zmd, dzone, bzone, 0);
+	if (ret == 0) {
+		/*
+		 * Free the data zone and remap the chunk to
+		 * the buffer zone.
+		 */
+		dmz_invalidate_blocks(zmd, dzone, 0, zrc->dev->zone_nr_blocks);
+		dmz_lock_map(zmd);
+		dmz_unmap_zone(zmd, bzone);
+		dmz_unmap_zone(zmd, dzone);
+		dmz_unlock_zone_reclaim(dzone);
+		dmz_free_zone(zmd, dzone);
+		dmz_map_zone(zmd, bzone, chunk);
+		dmz_unlock_map(zmd);
+	}
+
+	dmz_unlock_flush(zmd);
+
+	return 0;
+}
+
+/*
+ * Move valid blocks of the random data zone dzone into a free sequential zone.
+ * Once blocks are moved, remap the zone chunk to the sequential zone.
+ */
+static int dmz_reclaim_rnd_data(struct dmz_reclaim *zrc, struct dm_zone *dzone)
+{
+	unsigned int chunk = dzone->chunk;
+	struct dm_zone *szone = NULL;
+	struct dmz_metadata *zmd = zrc->metadata;
+	int ret;
+
+	/* Get a free sequential zone */
+	dmz_lock_map(zmd);
+	szone = dmz_alloc_zone(zmd, DMZ_ALLOC_RECLAIM);
+	dmz_unlock_map(zmd);
+	if (!szone)
+		return -ENOSPC;
+
+	dmz_dev_debug(zrc->dev,
+		      "Chunk %u, move rnd zone %u (weight %u) to seq zone %u",
+		      chunk, dmz_id(zmd, dzone), dmz_weight(dzone),
+		      dmz_id(zmd, szone));
+
+	/* Flush the random data zone into the sequential zone */
+	ret = dmz_reclaim_copy(zrc, dzone, szone);
+
+	dmz_lock_flush(zmd);
+
+	if (ret == 0) {
+		/* Validate copied blocks */
+		ret = dmz_copy_valid_blocks(zmd, dzone, szone);
+	}
+	if (ret) {
+		/* Free the sequential zone */
+		dmz_lock_map(zmd);
+		dmz_free_zone(zmd, szone);
+		dmz_unlock_map(zmd);
+	} else {
+		/* Free the data zone and remap the chunk */
+		dmz_invalidate_blocks(zmd, dzone, 0, zrc->dev->zone_nr_blocks);
+		dmz_lock_map(zmd);
+		dmz_unmap_zone(zmd, dzone);
+		dmz_unlock_zone_reclaim(dzone);
+		dmz_free_zone(zmd, dzone);
+		dmz_map_zone(zmd, szone, chunk);
+		dmz_unlock_map(zmd);
+	}
+
+	dmz_unlock_flush(zmd);
+
+	return 0;
+}
+
+/*
+ * Reclaim an empty zone.
+ */
+static void dmz_reclaim_empty(struct dmz_reclaim *zrc, struct dm_zone *dzone)
+{
+	struct dmz_metadata *zmd = zrc->metadata;
+
+	dmz_lock_flush(zmd);
+	dmz_lock_map(zmd);
+	dmz_unmap_zone(zmd, dzone);
+	dmz_unlock_zone_reclaim(dzone);
+	dmz_free_zone(zmd, dzone);
+	dmz_unlock_map(zmd);
+	dmz_unlock_flush(zmd);
+}
+
+/*
+ * Find a candidate zone for reclaim and process it.
+ */
+static void dmz_reclaim(struct dmz_reclaim *zrc)
+{
+	struct dmz_metadata *zmd = zrc->metadata;
+	struct dm_zone *dzone;
+	struct dm_zone *rzone;
+	unsigned long start;
+	int ret;
+
+	/* Get a data zone */
+	dzone = dmz_get_zone_for_reclaim(zmd);
+	if (!dzone)
+		return;
+
+	start = jiffies;
+
+	if (dmz_is_rnd(dzone)) {
+		if (!dmz_weight(dzone)) {
+			/* Empty zone */
+			dmz_reclaim_empty(zrc, dzone);
+			ret = 0;
+		} else {
+			/*
+			 * Reclaim the random data zone by moving its
+			 * valid data blocks to a free sequential zone.
+			 */
+			ret = dmz_reclaim_rnd_data(zrc, dzone);
+		}
+		rzone = dzone;
+
+	} else {
+		struct dm_zone *bzone = dzone->bzone;
+		sector_t chunk_block = 0;
+
+		ret = dmz_first_valid_block(zmd, bzone, &chunk_block);
+		if (ret < 0)
+			goto out;
+
+		if (ret == 0 || chunk_block >= dzone->wp_block) {
+			/*
+			 * The buffer zone is empty or its valid blocks are
+			 * after the data zone write pointer.
+			 */
+			ret = dmz_reclaim_buf(zrc, dzone);
+			rzone = bzone;
+		} else {
+			/*
+			 * Reclaim the data zone by merging it into the
+			 * buffer zone so that the buffer zone itself can
+			 * be later reclaimed.
+			 */
+			ret = dmz_reclaim_seq_data(zrc, dzone);
+			rzone = dzone;
+		}
+	}
+out:
+	if (ret) {
+		dmz_unlock_zone_reclaim(dzone);
+		return;
+	}
+
+	(void) dmz_flush_metadata(zrc->metadata);
+
+	dmz_dev_debug(zrc->dev, "Reclaimed zone %u in %u ms",
+		      dmz_id(zmd, rzone), jiffies_to_msecs(jiffies - start));
+}
+
+/*
+ * Test if the target device is idle.
+ */
+static inline int dmz_target_idle(struct dmz_reclaim *zrc)
+{
+	return time_is_before_jiffies(zrc->atime + DMZ_IDLE_PERIOD);
+}
+
+/*
+ * Test if reclaim is necessary.
+ */
+static bool dmz_should_reclaim(struct dmz_reclaim *zrc)
+{
+	struct dmz_metadata *zmd = zrc->metadata;
+	unsigned int nr_rnd = dmz_nr_rnd_zones(zmd);
+	unsigned int nr_unmap_rnd = dmz_nr_unmap_rnd_zones(zmd);
+	unsigned int p_unmap_rnd = nr_unmap_rnd * 100 / nr_rnd;
+
+	/* Reclaim when idle */
+	if (dmz_target_idle(zrc) && nr_unmap_rnd < nr_rnd)
+		return true;
+
+	/* If there are still plenty of random zones, do not reclaim */
+	if (p_unmap_rnd >= DMZ_RECLAIM_HIGH_UNMAP_RND)
+		return false;
+
+	/*
+	 * If the percentage of unmappped random zones is low,
+	 * reclaim even if the target is busy.
+	 */
+	return p_unmap_rnd <= DMZ_RECLAIM_LOW_UNMAP_RND;
+}
+
+/*
+ * Reclaim work function.
+ */
+static void dmz_reclaim_work(struct work_struct *work)
+{
+	struct dmz_reclaim *zrc = container_of(work, struct dmz_reclaim, work.work);
+	struct dmz_metadata *zmd = zrc->metadata;
+	unsigned int nr_rnd, nr_unmap_rnd;
+	unsigned int p_unmap_rnd;
+
+	if (!dmz_should_reclaim(zrc)) {
+		mod_delayed_work(zrc->wq, &zrc->work, DMZ_IDLE_PERIOD);
+		return;
+	}
+
+	/*
+	 * We need to start reclaiming random zones: set up zone copy
+	 * throttling to either go fast if we are very low on random zones
+	 * and slower if there are still some free random zones to avoid
+	 * as much as possible to negatively impact the user workload.
+	 */
+	nr_rnd = dmz_nr_rnd_zones(zmd);
+	nr_unmap_rnd = dmz_nr_unmap_rnd_zones(zmd);
+	p_unmap_rnd = nr_unmap_rnd * 100 / nr_rnd;
+	if (dmz_target_idle(zrc) || p_unmap_rnd < DMZ_RECLAIM_LOW_UNMAP_RND / 2) {
+		/* Idle or very low percentage: go fast */
+		zrc->kc_throttle.throttle = 100;
+	} else {
+		/* Busy but we still have some random zone: throttle */
+		zrc->kc_throttle.throttle = min(75U, 100U - p_unmap_rnd / 2);
+	}
+
+	dmz_dev_debug(zrc->dev,
+		      "Reclaim (%u): %s, %u%% free rnd zones (%u/%u)",
+		      zrc->kc_throttle.throttle,
+		      (dmz_target_idle(zrc) ? "Idle" : "Busy"),
+		      p_unmap_rnd, nr_unmap_rnd, nr_rnd);
+
+	dmz_reclaim(zrc);
+
+	dmz_schedule_reclaim(zrc);
+}
+
+/*
+ * Initialize reclaim.
+ */
+int dmz_ctr_reclaim(struct dmz_dev *dev, struct dmz_metadata *zmd,
+		    struct dmz_reclaim **reclaim)
+{
+	struct dmz_reclaim *zrc;
+	int ret;
+
+	zrc = kzalloc(sizeof(struct dmz_reclaim), GFP_KERNEL);
+	if (!zrc)
+		return -ENOMEM;
+
+	zrc->dev = dev;
+	zrc->metadata = zmd;
+	zrc->atime = jiffies;
+
+	/* Reclaim kcopyd client */
+	zrc->kc = dm_kcopyd_client_create(&zrc->kc_throttle);
+	if (IS_ERR(zrc->kc)) {
+		ret = PTR_ERR(zrc->kc);
+		zrc->kc = NULL;
+		goto err;
+	}
+
+	/* Reclaim work */
+	INIT_DELAYED_WORK(&zrc->work, dmz_reclaim_work);
+	zrc->wq = alloc_ordered_workqueue("dmz_rwq_%s", WQ_MEM_RECLAIM,
+					  dev->name);
+	if (!zrc->wq) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	*reclaim = zrc;
+	queue_delayed_work(zrc->wq, &zrc->work, 0);
+
+	return 0;
+err:
+	if (zrc->kc)
+		dm_kcopyd_client_destroy(zrc->kc);
+	kfree(zrc);
+
+	return ret;
+}
+
+/*
+ * Terminate reclaim.
+ */
+void dmz_dtr_reclaim(struct dmz_reclaim *zrc)
+{
+	cancel_delayed_work_sync(&zrc->work);
+	destroy_workqueue(zrc->wq);
+	dm_kcopyd_client_destroy(zrc->kc);
+	kfree(zrc);
+}
+
+/*
+ * Suspend reclaim.
+ */
+void dmz_suspend_reclaim(struct dmz_reclaim *zrc)
+{
+	cancel_delayed_work_sync(&zrc->work);
+}
+
+/*
+ * Resume reclaim.
+ */
+void dmz_resume_reclaim(struct dmz_reclaim *zrc)
+{
+	queue_delayed_work(zrc->wq, &zrc->work, DMZ_IDLE_PERIOD);
+}
+
+/*
+ * BIO accounting.
+ */
+void dmz_reclaim_bio_acc(struct dmz_reclaim *zrc)
+{
+	zrc->atime = jiffies;
+}
+
+/*
+ * Start reclaim if necessary.
+ */
+void dmz_schedule_reclaim(struct dmz_reclaim *zrc)
+{
+	if (dmz_should_reclaim(zrc))
+		mod_delayed_work(zrc->wq, &zrc->work, 0);
+}
+

include/linux/dm-kcopyd.h

@@ -20,6 +20,7 @@
 #define DM_KCOPYD_MAX_REGIONS 8
 
 #define DM_KCOPYD_IGNORE_ERROR 1
+#define DM_KCOPYD_WRITE_SEQ    2
 
 struct dm_kcopyd_throttle {
 	unsigned throttle;