Merge tag 'dm-3.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm

Pull dm update from Alasdair G Kergon:
 "Miscellaneous device-mapper fixes, cleanups and performance
  improvements.

  Of particular note:
   - Disable broken WRITE SAME support in all targets except linear and
     striped.  Use it when kcopyd is zeroing blocks.
   - Remove several mempools from targets by moving the data into the
     bio's new front_pad area(which dm calls 'per_bio_data').
   - Fix a race in thin provisioning if discards are misused.
   - Prevent userspace from interfering with the ioctl parameters and
     use kmalloc for the data buffer if it's small instead of vmalloc.
   - Throttle some annoying error messages when I/O fails."

* tag 'dm-3.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm: (36 commits)
  dm stripe: add WRITE SAME support
  dm: remove map_info
  dm snapshot: do not use map_context
  dm thin: dont use map_context
  dm raid1: dont use map_context
  dm flakey: dont use map_context
  dm raid1: rename read_record to bio_record
  dm: move target request nr to dm_target_io
  dm snapshot: use per_bio_data
  dm verity: use per_bio_data
  dm raid1: use per_bio_data
  dm: introduce per_bio_data
  dm kcopyd: add WRITE SAME support to dm_kcopyd_zero
  dm linear: add WRITE SAME support
  dm: add WRITE SAME support
  dm: prepare to support WRITE SAME
  dm ioctl: use kmalloc if possible
  dm ioctl: remove PF_MEMALLOC
  dm persistent data: improve improve space map block alloc failure message
  dm thin: use DMERR_LIMIT for errors
  ...

28 files changed, 473 insertions, 433 deletions

diff --git a/drivers/md/dm-bio-prison.c b/drivers/md/dm-bio-prison.c
index e4e84156745..aefb78e3cbf 100644
--- a/drivers/md/dm-bio-prison.c
+++ b/drivers/md/dm-bio-prison.c
@@ -208,31 +208,6 @@ void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios)
 EXPORT_SYMBOL_GPL(dm_cell_release);
 
 /*
- * There are a couple of places where we put a bio into a cell briefly
- * before taking it out again.  In these situations we know that no other
- * bio may be in the cell.  This function releases the cell, and also does
- * a sanity check.
- */
-static void __cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
-{
-	BUG_ON(cell->holder != bio);
-	BUG_ON(!bio_list_empty(&cell->bios));
-
-	__cell_release(cell, NULL);
-}
-
-void dm_cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
-{
-	unsigned long flags;
-	struct dm_bio_prison *prison = cell->prison;
-
-	spin_lock_irqsave(&prison->lock, flags);
-	__cell_release_singleton(cell, bio);
-	spin_unlock_irqrestore(&prison->lock, flags);
-}
-EXPORT_SYMBOL_GPL(dm_cell_release_singleton);
-
-/*
  * Sometimes we don't want the holder, just the additional bios.
  */
 static void __cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h
index 4e0ac376700..53d1a7a84e2 100644
--- a/drivers/md/dm-bio-prison.h
+++ b/drivers/md/dm-bio-prison.h
@@ -44,7 +44,6 @@ int dm_bio_detain(struct dm_bio_prison *prison, struct dm_cell_key *key,
 		  struct bio *inmate, struct dm_bio_prison_cell **ref);
 
 void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios);
-void dm_cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio); // FIXME: bio arg not needed
 void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates);
 void dm_cell_error(struct dm_bio_prison_cell *cell);
 
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index bbf459bca61..f7369f9d859 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1689,8 +1689,7 @@ bad:
 	return ret;
 }
 
-static int crypt_map(struct dm_target *ti, struct bio *bio,
-		     union map_info *map_context)
+static int crypt_map(struct dm_target *ti, struct bio *bio)
 {
 	struct dm_crypt_io *io;
 	struct crypt_config *cc = ti->private;
@@ -1846,7 +1845,7 @@ static int crypt_iterate_devices(struct dm_target *ti,
 
 static struct target_type crypt_target = {
 	.name   = "crypt",
-	.version = {1, 11, 0},
+	.version = {1, 12, 0},
 	.module = THIS_MODULE,
 	.ctr    = crypt_ctr,
 	.dtr    = crypt_dtr,
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index f53846f9ab5..cc1bd048acb 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -274,8 +274,7 @@ static void delay_resume(struct dm_target *ti)
 	atomic_set(&dc->may_delay, 1);
 }
 
-static int delay_map(struct dm_target *ti, struct bio *bio,
-		     union map_info *map_context)
+static int delay_map(struct dm_target *ti, struct bio *bio)
 {
 	struct delay_c *dc = ti->private;
 
@@ -338,7 +337,7 @@ out:
 
 static struct target_type delay_target = {
 	.name	     = "delay",
-	.version     = {1, 1, 0},
+	.version     = {1, 2, 0},
 	.module      = THIS_MODULE,
 	.ctr	     = delay_ctr,
 	.dtr	     = delay_dtr,
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index cc15543a6ad..9721f2ffb1a 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -39,6 +39,10 @@ enum feature_flag_bits {
 	DROP_WRITES
 };
 
+struct per_bio_data {
+	bool bio_submitted;
+};
+
 static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
 			  struct dm_target *ti)
 {
@@ -214,6 +218,7 @@ static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->num_flush_requests = 1;
 	ti->num_discard_requests = 1;
+	ti->per_bio_data_size = sizeof(struct per_bio_data);
 	ti->private = fc;
 	return 0;
 
@@ -265,11 +270,12 @@ static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
 	}
 }
 
-static int flakey_map(struct dm_target *ti, struct bio *bio,
-		      union map_info *map_context)
+static int flakey_map(struct dm_target *ti, struct bio *bio)
 {
 	struct flakey_c *fc = ti->private;
 	unsigned elapsed;
+	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
+	pb->bio_submitted = false;
 
 	/* Are we alive ? */
 	elapsed = (jiffies - fc->start_time) / HZ;
@@ -277,7 +283,7 @@ static int flakey_map(struct dm_target *ti, struct bio *bio,
 		/*
 		 * Flag this bio as submitted while down.
 		 */
-		map_context->ll = 1;
+		pb->bio_submitted = true;
 
 		/*
 		 * Map reads as normal.
@@ -314,17 +320,16 @@ map_bio:
 	return DM_MAPIO_REMAPPED;
 }
 
-static int flakey_end_io(struct dm_target *ti, struct bio *bio,
-			 int error, union map_info *map_context)
+static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error)
 {
 	struct flakey_c *fc = ti->private;
-	unsigned bio_submitted_while_down = map_context->ll;
+	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
 
 	/*
 	 * Corrupt successful READs while in down state.
 	 * If flags were specified, only corrupt those that match.
 	 */
-	if (fc->corrupt_bio_byte && !error && bio_submitted_while_down &&
+	if (fc->corrupt_bio_byte && !error && pb->bio_submitted &&
 	    (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
 	    all_corrupt_bio_flags_match(bio, fc))
 		corrupt_bio_data(bio, fc);
@@ -406,7 +411,7 @@ static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_
 
 static struct target_type flakey_target = {
 	.name   = "flakey",
-	.version = {1, 2, 0},
+	.version = {1, 3, 0},
 	.module = THIS_MODULE,
 	.ctr    = flakey_ctr,
 	.dtr    = flakey_dtr,
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 1c46f97d666..ea49834377c 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -287,7 +287,8 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
 	unsigned num_bvecs;
 	sector_t remaining = where->count;
 	struct request_queue *q = bdev_get_queue(where->bdev);
-	sector_t discard_sectors;
+	unsigned short logical_block_size = queue_logical_block_size(q);
+	sector_t num_sectors;
 
 	/*
 	 * where->count may be zero if rw holds a flush and we need to
@@ -297,7 +298,7 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
 		/*
 		 * Allocate a suitably sized-bio.
 		 */
-		if (rw & REQ_DISCARD)
+		if ((rw & REQ_DISCARD) || (rw & REQ_WRITE_SAME))
 			num_bvecs = 1;
 		else
 			num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev),
@@ -310,9 +311,21 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
 		store_io_and_region_in_bio(bio, io, region);
 
 		if (rw & REQ_DISCARD) {
-			discard_sectors = min_t(sector_t, q->limits.max_discard_sectors, remaining);
-			bio->bi_size = discard_sectors << SECTOR_SHIFT;
-			remaining -= discard_sectors;
+			num_sectors = min_t(sector_t, q->limits.max_discard_sectors, remaining);
+			bio->bi_size = num_sectors << SECTOR_SHIFT;
+			remaining -= num_sectors;
+		} else if (rw & REQ_WRITE_SAME) {
+			/*
+			 * WRITE SAME only uses a single page.
+			 */
+			dp->get_page(dp, &page, &len, &offset);
+			bio_add_page(bio, page, logical_block_size, offset);
+			num_sectors = min_t(sector_t, q->limits.max_write_same_sectors, remaining);
+			bio->bi_size = num_sectors << SECTOR_SHIFT;
+
+			offset = 0;
+			remaining -= num_sectors;
+			dp->next_page(dp);
 		} else while (remaining) {
 			/*
 			 * Try and add as many pages as possible.
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index afd95986d09..0666b5d14b8 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1543,7 +1543,21 @@ static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
 	return r;
 }
 
-static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
+#define DM_PARAMS_VMALLOC	0x0001	/* Params alloced with vmalloc not kmalloc */
+#define DM_WIPE_BUFFER		0x0010	/* Wipe input buffer before returning from ioctl */
+
+static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags)
+{
+	if (param_flags & DM_WIPE_BUFFER)
+		memset(param, 0, param_size);
+
+	if (param_flags & DM_PARAMS_VMALLOC)
+		vfree(param);
+	else
+		kfree(param);
+}
+
+static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param, int *param_flags)
 {
 	struct dm_ioctl tmp, *dmi;
 	int secure_data;
@@ -1556,7 +1570,21 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
 
 	secure_data = tmp.flags & DM_SECURE_DATA_FLAG;
 
-	dmi = vmalloc(tmp.data_size);
+	*param_flags = secure_data ? DM_WIPE_BUFFER : 0;
+
+	/*
+	 * Try to avoid low memory issues when a device is suspended.
+	 * Use kmalloc() rather than vmalloc() when we can.
+	 */
+	dmi = NULL;
+	if (tmp.data_size <= KMALLOC_MAX_SIZE)
+		dmi = kmalloc(tmp.data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
+
+	if (!dmi) {
+		dmi = __vmalloc(tmp.data_size, GFP_NOIO | __GFP_REPEAT | __GFP_HIGH, PAGE_KERNEL);
+		*param_flags |= DM_PARAMS_VMALLOC;
+	}
+
 	if (!dmi) {
 		if (secure_data && clear_user(user, tmp.data_size))
 			return -EFAULT;
@@ -1566,6 +1594,14 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
 	if (copy_from_user(dmi, user, tmp.data_size))
 		goto bad;
 
+	/*
+	 * Abort if something changed the ioctl data while it was being copied.
+	 */
+	if (dmi->data_size != tmp.data_size) {
+		DMERR("rejecting ioctl: data size modified while processing parameters");
+		goto bad;
+	}
+
 	/* Wipe the user buffer so we do not return it to userspace */
 	if (secure_data && clear_user(user, tmp.data_size))
 		goto bad;
@@ -1574,9 +1610,8 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
 	return 0;
 
 bad:
-	if (secure_data)
-		memset(dmi, 0, tmp.data_size);
-	vfree(dmi);
+	free_params(dmi, tmp.data_size, *param_flags);
+
 	return -EFAULT;
 }
 
@@ -1613,7 +1648,7 @@ static int validate_params(uint cmd, struct dm_ioctl *param)
 static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
 {
 	int r = 0;
-	int wipe_buffer;
+	int param_flags;
 	unsigned int cmd;
 	struct dm_ioctl *uninitialized_var(param);
 	ioctl_fn fn = NULL;
@@ -1649,24 +1684,14 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
 	}
 
 	/*
-	 * Trying to avoid low memory issues when a device is
-	 * suspended.
-	 */
-	current->flags |= PF_MEMALLOC;
-
-	/*
 	 * Copy the parameters into kernel space.
 	 */
-	r = copy_params(user, &param);
-
-	current->flags &= ~PF_MEMALLOC;
+	r = copy_params(user, &param, &param_flags);
 
 	if (r)
 		return r;
 
 	input_param_size = param->data_size;
-	wipe_buffer = param->flags & DM_SECURE_DATA_FLAG;
-
 	r = validate_params(cmd, param);
 	if (r)
 		goto out;
@@ -1681,10 +1706,7 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
 		r = -EFAULT;
 
 out:
-	if (wipe_buffer)
-		memset(param, 0, input_param_size);
-
-	vfree(param);
+	free_params(param, input_param_size, param_flags);
 	return r;
 }
 
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index bed444c93d8..68c02673263 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -349,7 +349,7 @@ static void complete_io(unsigned long error, void *context)
 	struct dm_kcopyd_client *kc = job->kc;
 
 	if (error) {
-		if (job->rw == WRITE)
+		if (job->rw & WRITE)
 			job->write_err |= error;
 		else
 			job->read_err = 1;
@@ -361,7 +361,7 @@ static void complete_io(unsigned long error, void *context)
 		}
 	}
 
-	if (job->rw == WRITE)
+	if (job->rw & WRITE)
 		push(&kc->complete_jobs, job);
 
 	else {
@@ -432,7 +432,7 @@ static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc,
 
 		if (r < 0) {
 			/* error this rogue job */
-			if (job->rw == WRITE)
+			if (job->rw & WRITE)
 				job->write_err = (unsigned long) -1L;
 			else
 				job->read_err = 1;
@@ -585,6 +585,7 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
 		   unsigned int flags, dm_kcopyd_notify_fn fn, void *context)
 {
 	struct kcopyd_job *job;
+	int i;
 
 	/*
 	 * Allocate an array of jobs consisting of one master job
@@ -611,7 +612,16 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
 		memset(&job->source, 0, sizeof job->source);
 		job->source.count = job->dests[0].count;
 		job->pages = &zero_page_list;
-		job->rw = WRITE;
+
+		/*
+		 * Use WRITE SAME to optimize zeroing if all dests support it.
+		 */
+		job->rw = WRITE | REQ_WRITE_SAME;
+		for (i = 0; i < job->num_dests; i++)
+			if (!bdev_write_same(job->dests[i].bdev)) {
+				job->rw = WRITE;
+				break;
+			}
 	}
 
 	job->fn = fn;
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 1bf19a93eef..328cad5617a 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -55,6 +55,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->num_flush_requests = 1;
 	ti->num_discard_requests = 1;
+	ti->num_write_same_requests = 1;
 	ti->private = lc;
 	return 0;
 
@@ -87,8 +88,7 @@ static void linear_map_bio(struct dm_target *ti, struct bio *bio)
 		bio->bi_sector = linear_map_sector(ti, bio->bi_sector);
 }
 
-static int linear_map(struct dm_target *ti, struct bio *bio,
-		      union map_info *map_context)
+static int linear_map(struct dm_target *ti, struct bio *bio)
 {
 	linear_map_bio(ti, bio);
 
@@ -155,7 +155,7 @@ static int linear_iterate_devices(struct dm_target *ti,
 
 static struct target_type linear_target = {
 	.name   = "linear",
-	.version = {1, 1, 0},
+	.version = {1, 2, 0},
 	.module = THIS_MODULE,
 	.ctr    = linear_ctr,
 	.dtr    = linear_dtr,
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 45d94a7e7f6..3d8984edeff 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -295,9 +295,11 @@ static int validate_region_size(struct raid_set *rs, unsigned long region_size)
 		 * Choose a reasonable default.  All figures in sectors.
 		 */
 		if (min_region_size > (1 << 13)) {
+			/* If not a power of 2, make it the next power of 2 */
+			if (min_region_size & (min_region_size - 1))
+				region_size = 1 << fls(region_size);
 			DMINFO("Choosing default region size of %lu sectors",
 			       region_size);
-			region_size = min_region_size;
 		} else {
 			DMINFO("Choosing default region size of 4MiB");
 			region_size = 1 << 13; /* sectors */
@@ -1216,7 +1218,7 @@ static void raid_dtr(struct dm_target *ti)
 	context_free(rs);
 }
 
-static int raid_map(struct dm_target *ti, struct bio *bio, union map_info *map_context)
+static int raid_map(struct dm_target *ti, struct bio *bio)
 {
 	struct raid_set *rs = ti->private;
 	struct mddev *mddev = &rs->md;
@@ -1430,7 +1432,7 @@ static void raid_resume(struct dm_target *ti)
 
 static struct target_type raid_target = {
 	.name = "raid",
-	.version = {1, 3, 1},
+	.version = {1, 4, 0},
 	.module = THIS_MODULE,
 	.ctr = raid_ctr,
 	.dtr = raid_dtr,
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index fd61f98ee1f..fa519185ebb 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -61,7 +61,6 @@ struct mirror_set {
 	struct dm_region_hash *rh;
 	struct dm_kcopyd_client *kcopyd_client;
 	struct dm_io_client *io_client;
-	mempool_t *read_record_pool;
 
 	/* recovery */
 	region_t nr_regions;
@@ -139,14 +138,13 @@ static void dispatch_bios(void *context, struct bio_list *bio_list)
 		queue_bio(ms, bio, WRITE);
 }
 
-#define MIN_READ_RECORDS 20
-struct dm_raid1_read_record {
+struct dm_raid1_bio_record {
 	struct mirror *m;
+	/* if details->bi_bdev == NULL, details were not saved */
 	struct dm_bio_details details;
+	region_t write_region;
 };
 
-static struct kmem_cache *_dm_raid1_read_record_cache;
-
 /*
  * Every mirror should look like this one.
  */
@@ -876,19 +874,9 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors,
 	atomic_set(&ms->suspend, 0);
 	atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
 
-	ms->read_record_pool = mempool_create_slab_pool(MIN_READ_RECORDS,
-						_dm_raid1_read_record_cache);
-
-	if (!ms->read_record_pool) {
-		ti->error = "Error creating mirror read_record_pool";
-		kfree(ms);
-		return NULL;
-	}
-
 	ms->io_client = dm_io_client_create();
 	if (IS_ERR(ms->io_client)) {
 		ti->error = "Error creating dm_io client";
-		mempool_destroy(ms->read_record_pool);
 		kfree(ms);
  		return NULL;
 	}
@@ -900,7 +888,6 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors,
 	if (IS_ERR(ms->rh)) {
 		ti->error = "Error creating dirty region hash";
 		dm_io_client_destroy(ms->io_client);
-		mempool_destroy(ms->read_record_pool);
 		kfree(ms);
 		return NULL;
 	}
@@ -916,7 +903,6 @@ static void free_context(struct mirror_set *ms, struct dm_target *ti,
 
 	dm_io_client_destroy(ms->io_client);
 	dm_region_hash_destroy(ms->rh);
-	mempool_destroy(ms->read_record_pool);
 	kfree(ms);
 }
 
@@ -1088,6 +1074,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->num_flush_requests = 1;
 	ti->num_discard_requests = 1;
+	ti->per_bio_data_size = sizeof(struct dm_raid1_bio_record);
 	ti->discard_zeroes_data_unsupported = true;
 
 	ms->kmirrord_wq = alloc_workqueue("kmirrord",
@@ -1155,18 +1142,20 @@ static void mirror_dtr(struct dm_target *ti)
 /*
  * Mirror mapping function
  */
-static int mirror_map(struct dm_target *ti, struct bio *bio,
-		      union map_info *map_context)
+static int mirror_map(struct dm_target *ti, struct bio *bio)
 {
 	int r, rw = bio_rw(bio);
 	struct mirror *m;
 	struct mirror_set *ms = ti->private;
-	struct dm_raid1_read_record *read_record = NULL;
 	struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
+	struct dm_raid1_bio_record *bio_record =
+	  dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
+
+	bio_record->details.bi_bdev = NULL;
 
 	if (rw == WRITE) {
 		/* Save region for mirror_end_io() handler */
-		map_context->ll = dm_rh_bio_to_region(ms->rh, bio);
+		bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio);
 		queue_bio(ms, bio, rw);
 		return DM_MAPIO_SUBMITTED;
 	}
@@ -1194,33 +1183,29 @@ static int mirror_map(struct dm_target *ti, struct bio *bio,
 	if (unlikely(!m))
 		return -EIO;
 
-	read_record = mempool_alloc(ms->read_record_pool, GFP_NOIO);
-	if (likely(read_record)) {
-		dm_bio_record(&read_record->details, bio);
-		map_context->ptr = read_record;
-		read_record->m = m;
-	}
+	dm_bio_record(&bio_record->details, bio);
+	bio_record->m = m;
 
 	map_bio(m, bio);
 
 	return DM_MAPIO_REMAPPED;
 }
 
-static int mirror_end_io(struct dm_target *ti, struct bio *bio,
-			 int error, union map_info *map_context)
+static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
 {
 	int rw = bio_rw(bio);
 	struct mirror_set *ms = (struct mirror_set *) ti->private;
 	struct mirror *m = NULL;
 	struct dm_bio_details *bd = NULL;
-	struct dm_raid1_read_record *read_record = map_context->ptr;
+	struct dm_raid1_bio_record *bio_record =
+	  dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
 
 	/*
 	 * We need to dec pending if this was a write.
 	 */
 	if (rw == WRITE) {
 		if (!(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD)))
-			dm_rh_dec(ms->rh, map_context->ll);
+			dm_rh_dec(ms->rh, bio_record->write_region);
 		return error;
 	}
 
@@ -1231,7 +1216,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
 		goto out;
 
 	if (unlikely(error)) {
-		if (!read_record) {
+		if (!bio_record->details.bi_bdev) {
 			/*
 			 * There wasn't enough memory to record necessary
 			 * information for a retry or there was no other
@@ -1241,7 +1226,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
 			return -EIO;
 		}
 
-		m = read_record->m;
+		m = bio_record->m;
 
 		DMERR("Mirror read failed from %s. Trying alternative device.",
 		      m->dev->name);
@@ -1253,22 +1238,18 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
 		 * mirror.
 		 */
 		if (default_ok(m) || mirror_available(ms, bio)) {
-			bd = &read_record->details;
+			bd = &bio_record->details;
 
 			dm_bio_restore(bd, bio);
-			mempool_free(read_record, ms->read_record_pool);
-			map_context->ptr = NULL;
+			bio_record->details.bi_bdev = NULL;
 			queue_bio(ms, bio, rw);
-			return 1;
+			return DM_ENDIO_INCOMPLETE;
 		}
 		DMERR("All replicated volumes dead, failing I/O");
 	}
 
 out:
-	if (read_record) {
-		mempool_free(read_record, ms->read_record_pool);
-		map_context->ptr = NULL;
-	}
+	bio_record->details.bi_bdev = NULL;
 
 	return error;
 }
@@ -1422,7 +1403,7 @@ static int mirror_iterate_devices(struct dm_target *ti,
 
 static struct target_type mirror_target = {
 	.name	 = "mirror",
-	.version = {1, 12, 1},
+	.version = {1, 13, 1},
 	.module	 = THIS_MODULE,
 	.ctr	 = mirror_ctr,
 	.dtr	 = mirror_dtr,
@@ -1439,13 +1420,6 @@ static int __init dm_mirror_init(void)
 {
 	int r;
 
-	_dm_raid1_read_record_cache = KMEM_CACHE(dm_raid1_read_record, 0);
-	if (!_dm_raid1_read_record_cache) {
-		DMERR("Can't allocate dm_raid1_read_record cache");
-		r = -ENOMEM;
-		goto bad_cache;
-	}
-
 	r = dm_register_target(&mirror_target);
 	if (r < 0) {
 		DMERR("Failed to register mirror target");
@@ -1455,15 +1429,12 @@ static int __init dm_mirror_init(void)
 	return 0;
 
 bad_target:
-	kmem_cache_destroy(_dm_raid1_read_record_cache);
-bad_cache:
 	return r;
 }
 
 static void __exit dm_mirror_exit(void)
 {
 	dm_unregister_target(&mirror_target);
-	kmem_cache_destroy(_dm_raid1_read_record_cache);
 }
 
 /* Module hooks */
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index a143921feaf..59fc18ae52c 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -79,7 +79,6 @@ struct dm_snapshot {
 
 	/* Chunks with outstanding reads */
 	spinlock_t tracked_chunk_lock;
-	mempool_t *tracked_chunk_pool;
 	struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
 
 	/* The on disk metadata handler */
@@ -191,35 +190,38 @@ struct dm_snap_tracked_chunk {
 	chunk_t chunk;
 };
 
-static struct kmem_cache *tracked_chunk_cache;
+static void init_tracked_chunk(struct bio *bio)
+{
+	struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk));
+	INIT_HLIST_NODE(&c->node);
+}
 
-static struct dm_snap_tracked_chunk *track_chunk(struct dm_snapshot *s,
-						 chunk_t chunk)
+static bool is_bio_tracked(struct bio *bio)
 {
-	struct dm_snap_tracked_chunk *c = mempool_alloc(s->tracked_chunk_pool,
-							GFP_NOIO);
-	unsigned long flags;
+	struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk));
+	return !hlist_unhashed(&c->node);
+}
+
+static void track_chunk(struct dm_snapshot *s, struct bio *bio, chunk_t chunk)
+{
+	struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk));
 
 	c->chunk = chunk;
 
-	spin_lock_irqsave(&s->tracked_chunk_lock, flags);
+	spin_lock_irq(&s->tracked_chunk_lock);
 	hlist_add_head(&c->node,
 		       &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)]);
-	spin_unlock_irqrestore(&s->tracked_chunk_lock, flags);
-
-	return c;
+	spin_unlock_irq(&s->tracked_chunk_lock);
 }
 
-static void stop_tracking_chunk(struct dm_snapshot *s,
-				struct dm_snap_tracked_chunk *c)
+static void stop_tracking_chunk(struct dm_snapshot *s, struct bio *bio)
 {
+	struct dm_snap_tracked_chunk *c = dm_per_bio_data(bio, sizeof(struct dm_snap_tracked_chunk));
 	unsigned long flags;
 
 	spin_lock_irqsave(&s->tracked_chunk_lock, flags);
 	hlist_del(&c->node);
 	spin_unlock_irqrestore(&s->tracked_chunk_lock, flags);
-
-	mempool_free(c, s->tracked_chunk_pool);
 }
 
 static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk)
@@ -1120,14 +1122,6 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad_pending_pool;
 	}
 
-	s->tracked_chunk_pool = mempool_create_slab_pool(MIN_IOS,
-							 tracked_chunk_cache);
-	if (!s->tracked_chunk_pool) {
-		ti->error = "Could not allocate tracked_chunk mempool for "
-			    "tracking reads";
-		goto bad_tracked_chunk_pool;
-	}
-
 	for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++)
 		INIT_HLIST_HEAD(&s->tracked_chunk_hash[i]);
 
@@ -1135,6 +1129,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->private = s;
 	ti->num_flush_requests = num_flush_requests;
+	ti->per_bio_data_size = sizeof(struct dm_snap_tracked_chunk);
 
 	/* Add snapshot to the list of snapshots for this origin */
 	/* Exceptions aren't triggered till snapshot_resume() is called */
@@ -1183,9 +1178,6 @@ bad_read_metadata:
 	unregister_snapshot(s);
 
 bad_load_and_register:
-	mempool_destroy(s->tracked_chunk_pool);
-
-bad_tracked_chunk_pool:
 	mempool_destroy(s->pending_pool);
 
 bad_pending_pool:
@@ -1290,8 +1282,6 @@ static void snapshot_dtr(struct dm_target *ti)
 		BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i]));
 #endif
 
-	mempool_destroy(s->tracked_chunk_pool);
-
 	__free_exceptions(s);
 
 	mempool_destroy(s->pending_pool);
@@ -1577,8 +1567,7 @@ static void remap_exception(struct dm_snapshot *s, struct dm_exception *e,
 					  s->store->chunk_mask);
 }
 
-static int snapshot_map(struct dm_target *ti, struct bio *bio,
-			union map_info *map_context)
+static int snapshot_map(struct dm_target *ti, struct bio *bio)
 {
 	struct dm_exception *e;
 	struct dm_snapshot *s = ti->private;
@@ -1586,6 +1575,8 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
 	chunk_t chunk;
 	struct dm_snap_pending_exception *pe = NULL;
 
+	init_tracked_chunk(bio);
+
 	if (bio->bi_rw & REQ_FLUSH) {
 		bio->bi_bdev = s->cow->bdev;
 		return DM_MAPIO_REMAPPED;
@@ -1670,7 +1661,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
 		}
 	} else {
 		bio->bi_bdev = s->origin->bdev;
-		map_context->ptr = track_chunk(s, chunk);
+		track_chunk(s, bio, chunk);
 	}
 
 out_unlock:
@@ -1691,20 +1682,20 @@ out:
  * If merging is currently taking place on the chunk in question, the
  * I/O is deferred by adding it to s->bios_queued_during_merge.
  */
-static int snapshot_merge_map(struct dm_target *ti, struct bio *bio,
-			      union map_info *map_context)
+static int snapshot_merge_map(struct dm_target *ti, struct bio *bio)
 {
 	struct dm_exception *e;
 	struct dm_snapshot *s = ti->private;
 	int r = DM_MAPIO_REMAPPED;
 	chunk_t chunk;
 
+	init_tracked_chunk(bio);
+
 	if (bio->bi_rw & REQ_FLUSH) {
-		if (!map_context->target_request_nr)
+		if (!dm_bio_get_target_request_nr(bio))
 			bio->bi_bdev = s->origin->bdev;
 		else
 			bio->bi_bdev = s->cow->bdev;
-		map_context->ptr = NULL;
 		return DM_MAPIO_REMAPPED;
 	}
 
@@ -1733,7 +1724,7 @@ static int snapshot_merge_map(struct dm_target *ti, struct bio *bio,
 		remap_exception(s, e, bio, chunk);
 
 		if (bio_rw(bio) == WRITE)
-			map_context->ptr = track_chunk(s, chunk);
+			track_chunk(s, bio, chunk);
 		goto out_unlock;
 	}
 
@@ -1751,14 +1742,12 @@ out_unlock:
 	return r;
 }
 
-static int snapshot_end_io(struct dm_target *ti, struct bio *bio,
-			   int error, union map_info *map_context)
+static int snapshot_end_io(struct dm_target *ti, struct bio *bio, int error)
 {
 	struct dm_snapshot *s = ti->private;
-	struct dm_snap_tracked_chunk *c = map_context->ptr;
 
-	if (c)
-		stop_tracking_chunk(s, c);
+	if (is_bio_tracked(bio))
+		stop_tracking_chunk(s, bio);
 
 	return 0;
 }
@@ -2127,8 +2116,7 @@ static void origin_dtr(struct dm_target *ti)
 	dm_put_device(ti, dev);
 }
 
-static int origin_map(struct dm_target *ti, struct bio *bio,
-		      union map_info *map_context)
+static int origin_map(struct dm_target *ti, struct bio *bio)
 {
 	struct dm_dev *dev = ti->private;
 	bio->bi_bdev = dev->bdev;
@@ -2193,7 +2181,7 @@ static int origin_iterate_devices(struct dm_target *ti,
 
 static struct target_type origin_target = {
 	.name    = "snapshot-origin",
-	.version = {1, 7, 1},
+	.version = {1, 8, 0},
 	.module  = THIS_MODULE,
 	.ctr     = origin_ctr,
 	.dtr     = origin_dtr,
@@ -2206,7 +2194,7 @@ static struct target_type origin_target = {
 
 static struct target_type snapshot_target = {
 	.name    = "snapshot",
-	.version = {1, 10, 0},
+	.version = {1, 11, 0},
 	.module  = THIS_MODULE,
 	.ctr     = snapshot_ctr,
 	.dtr     = snapshot_dtr,
@@ -2220,7 +2208,7 @@ static struct target_type snapshot_target = {
 
 static struct target_type merge_target = {
 	.name    = dm_snapshot_merge_target_name,
-	.version = {1, 1, 0},
+	.version = {1, 2, 0},
 	.module  = THIS_MODULE,
 	.ctr     = snapshot_ctr,
 	.dtr     = snapshot_dtr,
@@ -2281,17 +2269,8 @@ static int __init dm_snapshot_init(void)
 		goto bad_pending_cache;
 	}
 
-	tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0);
-	if (!tracked_chunk_cache) {
-		DMERR("Couldn't create cache to track chunks in use.");
-		r = -ENOMEM;
-		goto bad_tracked_chunk_cache;
-	}
-
 	return 0;
 
-bad_tracked_chunk_cache:
-	kmem_cache_destroy(pending_cache);
 bad_pending_cache:
 	kmem_cache_destroy(exception_cache);
 bad_exception_cache:
@@ -2317,7 +2296,6 @@ static void __exit dm_snapshot_exit(void)
 	exit_origin_hash();
 	kmem_cache_destroy(pending_cache);
 	kmem_cache_destroy(exception_cache);
-	kmem_cache_destroy(tracked_chunk_cache);
 
 	dm_exception_store_exit();
 }
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index e2f87653974..c89cde86d40 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -162,6 +162,7 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->num_flush_requests = stripes;
 	ti->num_discard_requests = stripes;
+	ti->num_write_same_requests = stripes;
 
 	sc->chunk_size = chunk_size;
 	if (chunk_size & (chunk_size - 1))
@@ -251,8 +252,8 @@ static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
 		*result += sc->chunk_size;		/* next chunk */
 }
 
-static int stripe_map_discard(struct stripe_c *sc, struct bio *bio,
-			      uint32_t target_stripe)
+static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
+			    uint32_t target_stripe)
 {
 	sector_t begin, end;
 
@@ -271,23 +272,23 @@ static int stripe_map_discard(struct stripe_c *sc, struct bio *bio,
 	}
 }
 
-static int stripe_map(struct dm_target *ti, struct bio *bio,
-		      union map_info *map_context)
+static int stripe_map(struct dm_target *ti, struct bio *bio)
 {
 	struct stripe_c *sc = ti->private;
 	uint32_t stripe;
 	unsigned target_request_nr;
 
 	if (bio->bi_rw & REQ_FLUSH) {
-		target_request_nr = map_context->target_request_nr;
+		target_request_nr = dm_bio_get_target_request_nr(bio);
 		BUG_ON(target_request_nr >= sc->stripes);
 		bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
 		return DM_MAPIO_REMAPPED;
 	}
-	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
-		target_request_nr = map_context->target_request_nr;
+	if (unlikely(bio->bi_rw & REQ_DISCARD) ||
+	    unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
+		target_request_nr = dm_bio_get_target_request_nr(bio);
 		BUG_ON(target_request_nr >= sc->stripes);
-		return stripe_map_discard(sc, bio, target_request_nr);
+		return stripe_map_range(sc, bio, target_request_nr);
 	}
 
 	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
@@ -342,8 +343,7 @@ static int stripe_status(struct dm_target *ti, status_type_t type,
 	return 0;
 }
 
-static int stripe_end_io(struct dm_target *ti, struct bio *bio,
-			 int error, union map_info *map_context)
+static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
 {
 	unsigned i;
 	char major_minor[16];
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 100368eb799..daf25d0890b 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -967,13 +967,22 @@ bool dm_table_request_based(struct dm_table *t)
 int dm_table_alloc_md_mempools(struct dm_table *t)
 {
 	unsigned type = dm_table_get_type(t);
+	unsigned per_bio_data_size = 0;
+	struct dm_target *tgt;
+	unsigned i;
 
 	if (unlikely(type == DM_TYPE_NONE)) {
 		DMWARN("no table type is set, can't allocate mempools");
 		return -EINVAL;
 	}
 
-	t->mempools = dm_alloc_md_mempools(type, t->integrity_supported);
+	if (type == DM_TYPE_BIO_BASED)
+		for (i = 0; i < t->num_targets; i++) {
+			tgt = t->targets + i;
+			per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
+		}
+
+	t->mempools = dm_alloc_md_mempools(type, t->integrity_supported, per_bio_data_size);
 	if (!t->mempools)
 		return -ENOMEM;
 
@@ -1414,6 +1423,33 @@ static bool dm_table_all_devices_attribute(struct dm_table *t,
 	return 1;
 }
 
+static int device_not_write_same_capable(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);
+
+	return q && !q->limits.max_write_same_sectors;
+}
+
+static bool dm_table_supports_write_same(struct dm_table *t)
+{
+	struct dm_target *ti;
+	unsigned i = 0;
+
+	while (i < dm_table_get_num_targets(t)) {
+		ti = dm_table_get_target(t, i++);
+
+		if (!ti->num_write_same_requests)
+			return false;
+
+		if (!ti->type->iterate_devices ||
+		    !ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
+			return false;
+	}
+
+	return true;
+}
+
 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 			       struct queue_limits *limits)
 {
@@ -1445,6 +1481,9 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	else
 		queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
 
+	if (!dm_table_supports_write_same(t))
+		q->limits.max_write_same_sectors = 0;
+
 	dm_table_set_integrity(t);
 
 	/*
diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c
index 8da366cf381..617d21a7725 100644
--- a/drivers/md/dm-target.c
+++ b/drivers/md/dm-target.c
@@ -126,15 +126,14 @@ static void io_err_dtr(struct dm_target *tt)
 	/* empty */
 }
 
-static int io_err_map(struct dm_target *tt, struct bio *bio,
-		      union map_info *map_context)
+static int io_err_map(struct dm_target *tt, struct bio *bio)
 {
 	return -EIO;
 }
 
 static struct target_type error_target = {
 	.name = "error",
-	.version = {1, 0, 1},
+	.version = {1, 1, 0},
 	.ctr  = io_err_ctr,
 	.dtr  = io_err_dtr,
 	.map  = io_err_map,
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 693e149e972..4d6e85367b8 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -408,7 +408,7 @@ static void __setup_btree_details(struct dm_pool_metadata *pmd)
 
 	pmd->tl_info.tm = pmd->tm;
 	pmd->tl_info.levels = 1;
-	pmd->tl_info.value_type.context = &pmd->info;
+	pmd->tl_info.value_type.context = &pmd->bl_info;
 	pmd->tl_info.value_type.size = sizeof(__le64);
 	pmd->tl_info.value_type.inc = subtree_inc;
 	pmd->tl_info.value_type.dec = subtree_dec;
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 058acf3a5ba..675ae527401 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -186,7 +186,6 @@ struct pool {
 
 	struct dm_thin_new_mapping *next_mapping;
 	mempool_t *mapping_pool;
-	mempool_t *endio_hook_pool;
 
 	process_bio_fn process_bio;
 	process_bio_fn process_discard;
@@ -304,7 +303,7 @@ static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
 	bio_list_init(master);
 
 	while ((bio = bio_list_pop(&bios))) {
-		struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
+		struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 
 		if (h->tc == tc)
 			bio_endio(bio, DM_ENDIO_REQUEUE);
@@ -368,6 +367,17 @@ static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
 		dm_thin_changed_this_transaction(tc->td);
 }
 
+static void inc_all_io_entry(struct pool *pool, struct bio *bio)
+{
+	struct dm_thin_endio_hook *h;
+
+	if (bio->bi_rw & REQ_DISCARD)
+		return;
+
+	h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
+	h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
+}
+
 static void issue(struct thin_c *tc, struct bio *bio)
 {
 	struct pool *pool = tc->pool;
@@ -474,7 +484,7 @@ static void copy_complete(int read_err, unsigned long write_err, void *context)
 static void overwrite_endio(struct bio *bio, int err)
 {
 	unsigned long flags;
-	struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
+	struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 	struct dm_thin_new_mapping *m = h->overwrite_mapping;
 	struct pool *pool = m->tc->pool;
 
@@ -499,8 +509,7 @@ static void overwrite_endio(struct bio *bio, int err)
 /*
  * This sends the bios in the cell back to the deferred_bios list.
  */
-static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell,
-		       dm_block_t data_block)
+static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
 {
 	struct pool *pool = tc->pool;
 	unsigned long flags;
@@ -513,17 +522,13 @@ static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell,
 }
 
 /*
- * Same as cell_defer above, except it omits one particular detainee,
- * a write bio that covers the block and has already been processed.
+ * Same as cell_defer except it omits the original holder of the cell.
  */
-static void cell_defer_except(struct thin_c *tc, struct dm_bio_prison_cell *cell)
+static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
 {
-	struct bio_list bios;
 	struct pool *pool = tc->pool;
 	unsigned long flags;
 
-	bio_list_init(&bios);
-
 	spin_lock_irqsave(&pool->lock, flags);
 	dm_cell_release_no_holder(cell, &pool->deferred_bios);
 	spin_unlock_irqrestore(&pool->lock, flags);
@@ -561,7 +566,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
 	 */
 	r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
 	if (r) {
-		DMERR("dm_thin_insert_block() failed");
+		DMERR_LIMIT("dm_thin_insert_block() failed");
 		dm_cell_error(m->cell);
 		goto out;
 	}
@@ -573,10 +578,10 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
 	 * the bios in the cell.
 	 */
 	if (bio) {
-		cell_defer_except(tc, m->cell);
+		cell_defer_no_holder(tc, m->cell);
 		bio_endio(bio, 0);
 	} else
-		cell_defer(tc, m->cell, m->data_block);
+		cell_defer(tc, m->cell);
 
 out:
 	list_del(&m->list);
@@ -588,8 +593,8 @@ static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
 	struct thin_c *tc = m->tc;
 
 	bio_io_error(m->bio);
-	cell_defer_except(tc, m->cell);
-	cell_defer_except(tc, m->cell2);
+	cell_defer_no_holder(tc, m->cell);
+	cell_defer_no_holder(tc, m->cell2);
 	mempool_free(m, tc->pool->mapping_pool);
 }
 
@@ -597,13 +602,15 @@ static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
 {
 	struct thin_c *tc = m->tc;
 
+	inc_all_io_entry(tc->pool, m->bio);
+	cell_defer_no_holder(tc, m->cell);
+	cell_defer_no_holder(tc, m->cell2);
+
 	if (m->pass_discard)
 		remap_and_issue(tc, m->bio, m->data_block);
 	else
 		bio_endio(m->bio, 0);
 
-	cell_defer_except(tc, m->cell);
-	cell_defer_except(tc, m->cell2);
 	mempool_free(m, tc->pool->mapping_pool);
 }
 
@@ -614,7 +621,7 @@ static void process_prepared_discard(struct dm_thin_new_mapping *m)
 
 	r = dm_thin_remove_block(tc->td, m->virt_block);
 	if (r)
-		DMERR("dm_thin_remove_block() failed");
+		DMERR_LIMIT("dm_thin_remove_block() failed");
 
 	process_prepared_discard_passdown(m);
 }
@@ -706,11 +713,12 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
 	 * bio immediately. Otherwise we use kcopyd to clone the data first.
 	 */
 	if (io_overwrites_block(pool, bio)) {
-		struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
+		struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 
 		h->overwrite_mapping = m;
 		m->bio = bio;
 		save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
+		inc_all_io_entry(pool, bio);
 		remap_and_issue(tc, bio, data_dest);
 	} else {
 		struct dm_io_region from, to;
@@ -727,7 +735,7 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
 				   0, copy_complete, m);
 		if (r < 0) {
 			mempool_free(m, pool->mapping_pool);
-			DMERR("dm_kcopyd_copy() failed");
+			DMERR_LIMIT("dm_kcopyd_copy() failed");
 			dm_cell_error(cell);
 		}
 	}
@@ -775,11 +783,12 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
 		process_prepared_mapping(m);
 
 	else if (io_overwrites_block(pool, bio)) {
-		struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
+		struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 
 		h->overwrite_mapping = m;
 		m->bio = bio;
 		save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
+		inc_all_io_entry(pool, bio);
 		remap_and_issue(tc, bio, data_block);
 	} else {
 		int r;
@@ -792,7 +801,7 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
 		r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
 		if (r < 0) {
 			mempool_free(m, pool->mapping_pool);
-			DMERR("dm_kcopyd_zero() failed");
+			DMERR_LIMIT("dm_kcopyd_zero() failed");
 			dm_cell_error(cell);
 		}
 	}
@@ -804,7 +813,7 @@ static int commit(struct pool *pool)
 
 	r = dm_pool_commit_metadata(pool->pmd);
 	if (r)
-		DMERR("commit failed, error = %d", r);
+		DMERR_LIMIT("commit failed: error = %d", r);
 
 	return r;
 }
@@ -889,7 +898,7 @@ static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
  */
 static void retry_on_resume(struct bio *bio)
 {
-	struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
+	struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 	struct thin_c *tc = h->tc;
 	struct pool *pool = tc->pool;
 	unsigned long flags;
@@ -936,7 +945,7 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 		 */
 		build_data_key(tc->td, lookup_result.block, &key2);
 		if (dm_bio_detain(tc->pool->prison, &key2, bio, &cell2)) {
-			dm_cell_release_singleton(cell, bio);
+			cell_defer_no_holder(tc, cell);
 			break;
 		}
 
@@ -962,13 +971,15 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 				wake_worker(pool);
 			}
 		} else {
+			inc_all_io_entry(pool, bio);
+			cell_defer_no_holder(tc, cell);
+			cell_defer_no_holder(tc, cell2);
+
 			/*
 			 * The DM core makes sure that the discard doesn't span
 			 * a block boundary.  So we submit the discard of a
 			 * partial block appropriately.
 			 */
-			dm_cell_release_singleton(cell, bio);
-			dm_cell_release_singleton(cell2, bio);
 			if ((!lookup_result.shared) && pool->pf.discard_passdown)
 				remap_and_issue(tc, bio, lookup_result.block);
 			else
@@ -980,13 +991,14 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 		/*
 		 * It isn't provisioned, just forget it.
 		 */
-		dm_cell_release_singleton(cell, bio);
+		cell_defer_no_holder(tc, cell);
 		bio_endio(bio, 0);
 		break;
 
 	default:
-		DMERR("discard: find block unexpectedly returned %d", r);
-		dm_cell_release_singleton(cell, bio);
+		DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
+			    __func__, r);
+		cell_defer_no_holder(tc, cell);
 		bio_io_error(bio);
 		break;
 	}
@@ -1012,7 +1024,8 @@ static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
 		break;
 
 	default:
-		DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
+		DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
+			    __func__, r);
 		dm_cell_error(cell);
 		break;
 	}
@@ -1037,11 +1050,12 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio,
 	if (bio_data_dir(bio) == WRITE && bio->bi_size)
 		break_sharing(tc, bio, block, &key, lookup_result, cell);
 	else {
-		struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
+		struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 
 		h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
+		inc_all_io_entry(pool, bio);
+		cell_defer_no_holder(tc, cell);
 
-		dm_cell_release_singleton(cell, bio);
 		remap_and_issue(tc, bio, lookup_result->block);
 	}
 }
@@ -1056,7 +1070,9 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
 	 * Remap empty bios (flushes) immediately, without provisioning.
 	 */
 	if (!bio->bi_size) {
-		dm_cell_release_singleton(cell, bio);
+		inc_all_io_entry(tc->pool, bio);
+		cell_defer_no_holder(tc, cell);
+
 		remap_and_issue(tc, bio, 0);
 		return;
 	}
@@ -1066,7 +1082,7 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
 	 */
 	if (bio_data_dir(bio) == READ) {
 		zero_fill_bio(bio);
-		dm_cell_release_singleton(cell, bio);
+		cell_defer_no_holder(tc, cell);
 		bio_endio(bio, 0);
 		return;
 	}
@@ -1085,7 +1101,8 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
 		break;
 
 	default:
-		DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
+		DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
+			    __func__, r);
 		set_pool_mode(tc->pool, PM_READ_ONLY);
 		dm_cell_error(cell);
 		break;
@@ -1111,34 +1128,31 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
 	r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
 	switch (r) {
 	case 0:
-		/*
-		 * We can release this cell now.  This thread is the only
-		 * one that puts bios into a cell, and we know there were
-		 * no preceding bios.
-		 */
-		/*
-		 * TODO: this will probably have to change when discard goes
-		 * back in.
-		 */
-		dm_cell_release_singleton(cell, bio);
-
-		if (lookup_result.shared)
+		if (lookup_result.shared) {
 			process_shared_bio(tc, bio, block, &lookup_result);
-		else
+			cell_defer_no_holder(tc, cell);
+		} else {
+			inc_all_io_entry(tc->pool, bio);
+			cell_defer_no_holder(tc, cell);
+
 			remap_and_issue(tc, bio, lookup_result.block);
+		}
 		break;
 
 	case -ENODATA:
 		if (bio_data_dir(bio) == READ && tc->origin_dev) {
-			dm_cell_release_singleton(cell, bio);
+			inc_all_io_entry(tc->pool, bio);
+			cell_defer_no_holder(tc, cell);
+
 			remap_to_origin_and_issue(tc, bio);
 		} else
 			provision_block(tc, bio, block, cell);
 		break;
 
 	default:
-		DMERR("dm_thin_find_block() failed, error = %d", r);
-		dm_cell_release_singleton(cell, bio);
+		DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
+			    __func__, r);
+		cell_defer_no_holder(tc, cell);
 		bio_io_error(bio);
 		break;
 	}
@@ -1156,8 +1170,10 @@ static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
 	case 0:
 		if (lookup_result.shared && (rw == WRITE) && bio->bi_size)
 			bio_io_error(bio);
-		else
+		else {
+			inc_all_io_entry(tc->pool, bio);
 			remap_and_issue(tc, bio, lookup_result.block);
+		}
 		break;
 
 	case -ENODATA:
@@ -1167,6 +1183,7 @@ static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
 		}
 
 		if (tc->origin_dev) {
+			inc_all_io_entry(tc->pool, bio);
 			remap_to_origin_and_issue(tc, bio);
 			break;
 		}
@@ -1176,7 +1193,8 @@ static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
 		break;
 
 	default:
-		DMERR("dm_thin_find_block() failed, error = %d", r);
+		DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
+			    __func__, r);
 		bio_io_error(bio);
 		break;
 	}
@@ -1207,7 +1225,7 @@ static void process_deferred_bios(struct pool *pool)
 	spin_unlock_irqrestore(&pool->lock, flags);
 
 	while ((bio = bio_list_pop(&bios))) {
-		struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
+		struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 		struct thin_c *tc = h->tc;
 
 		/*
@@ -1340,32 +1358,30 @@ static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
 	wake_worker(pool);
 }
 
-static struct dm_thin_endio_hook *thin_hook_bio(struct thin_c *tc, struct bio *bio)
+static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
 {
-	struct pool *pool = tc->pool;
-	struct dm_thin_endio_hook *h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO);
+	struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 
 	h->tc = tc;
 	h->shared_read_entry = NULL;
-	h->all_io_entry = bio->bi_rw & REQ_DISCARD ? NULL : dm_deferred_entry_inc(pool->all_io_ds);
+	h->all_io_entry = NULL;
 	h->overwrite_mapping = NULL;
-
-	return h;
 }
 
 /*
  * Non-blocking function called from the thin target's map function.
  */
-static int thin_bio_map(struct dm_target *ti, struct bio *bio,
-			union map_info *map_context)
+static int thin_bio_map(struct dm_target *ti, struct bio *bio)
 {
 	int r;
 	struct thin_c *tc = ti->private;
 	dm_block_t block = get_bio_block(tc, bio);
 	struct dm_thin_device *td = tc->td;
 	struct dm_thin_lookup_result result;
+	struct dm_bio_prison_cell *cell1, *cell2;
+	struct dm_cell_key key;
 
-	map_context->ptr = thin_hook_bio(tc, bio);
+	thin_hook_bio(tc, bio);
 
 	if (get_pool_mode(tc->pool) == PM_FAIL) {
 		bio_io_error(bio);
@@ -1400,12 +1416,25 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio,
 			 * shared flag will be set in their case.
 			 */
 			thin_defer_bio(tc, bio);
-			r = DM_MAPIO_SUBMITTED;
-		} else {
-			remap(tc, bio, result.block);
-			r = DM_MAPIO_REMAPPED;
+			return DM_MAPIO_SUBMITTED;
 		}
-		break;
+
+		build_virtual_key(tc->td, block, &key);
+		if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1))
+			return DM_MAPIO_SUBMITTED;
+
+		build_data_key(tc->td, result.block, &key);
+		if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2)) {
+			cell_defer_no_holder(tc, cell1);
+			return DM_MAPIO_SUBMITTED;
+		}
+
+		inc_all_io_entry(tc->pool, bio);
+		cell_defer_no_holder(tc, cell2);
+		cell_defer_no_holder(tc, cell1);
+
+		remap(tc, bio, result.block);
+		return DM_MAPIO_REMAPPED;
 
 	case -ENODATA:
 		if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
@@ -1414,8 +1443,7 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio,
 			 * of doing so.  Just error it.
 			 */
 			bio_io_error(bio);
-			r = DM_MAPIO_SUBMITTED;
-			break;
+			return DM_MAPIO_SUBMITTED;
 		}
 		/* fall through */
 
@@ -1425,8 +1453,7 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio,
 		 * provide the hint to load the metadata into cache.
 		 */
 		thin_defer_bio(tc, bio);
-		r = DM_MAPIO_SUBMITTED;
-		break;
+		return DM_MAPIO_SUBMITTED;
 
 	default:
 		/*
@@ -1435,11 +1462,8 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio,
 		 * pool is switched to fail-io mode.
 		 */
 		bio_io_error(bio);
-		r = DM_MAPIO_SUBMITTED;
-		break;
+		return DM_MAPIO_SUBMITTED;
 	}
-
-	return r;
 }
 
 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
@@ -1566,14 +1590,12 @@ static void __pool_destroy(struct pool *pool)
 	if (pool->next_mapping)
 		mempool_free(pool->next_mapping, pool->mapping_pool);
 	mempool_destroy(pool->mapping_pool);
-	mempool_destroy(pool->endio_hook_pool);
 	dm_deferred_set_destroy(pool->shared_read_ds);
 	dm_deferred_set_destroy(pool->all_io_ds);
 	kfree(pool);
 }
 
 static struct kmem_cache *_new_mapping_cache;
-static struct kmem_cache *_endio_hook_cache;
 
 static struct pool *pool_create(struct mapped_device *pool_md,
 				struct block_device *metadata_dev,
@@ -1667,13 +1689,6 @@ static struct pool *pool_create(struct mapped_device *pool_md,
 		goto bad_mapping_pool;
 	}
 
-	pool->endio_hook_pool = mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE,
-							 _endio_hook_cache);
-	if (!pool->endio_hook_pool) {
-		*error = "Error creating pool's endio_hook mempool";
-		err_p = ERR_PTR(-ENOMEM);
-		goto bad_endio_hook_pool;
-	}
 	pool->ref_count = 1;
 	pool->last_commit_jiffies = jiffies;
 	pool->pool_md = pool_md;
@@ -1682,8 +1697,6 @@ static struct pool *pool_create(struct mapped_device *pool_md,
 
 	return pool;
 
-bad_endio_hook_pool:
-	mempool_destroy(pool->mapping_pool);
 bad_mapping_pool:
 	dm_deferred_set_destroy(pool->all_io_ds);
 bad_all_io_ds:
@@ -1966,8 +1979,7 @@ out_unlock:
 	return r;
 }
 
-static int pool_map(struct dm_target *ti, struct bio *bio,
-		    union map_info *map_context)
+static int pool_map(struct dm_target *ti, struct bio *bio)
 {
 	int r;
 	struct pool_c *pt = ti->private;
@@ -2358,7 +2370,9 @@ static int pool_status(struct dm_target *ti, status_type_t type,
 		else
 			DMEMIT("rw ");
 
-		if (pool->pf.discard_enabled && pool->pf.discard_passdown)
+		if (!pool->pf.discard_enabled)
+			DMEMIT("ignore_discard");
+		else if (pool->pf.discard_passdown)
 			DMEMIT("discard_passdown");
 		else
 			DMEMIT("no_discard_passdown");
@@ -2454,7 +2468,7 @@ static struct target_type pool_target = {
 	.name = "thin-pool",
 	.features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
 		    DM_TARGET_IMMUTABLE,
-	.version = {1, 5, 0},
+	.version = {1, 6, 0},
 	.module = THIS_MODULE,
 	.ctr = pool_ctr,
 	.dtr = pool_dtr,
@@ -2576,6 +2590,7 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
 
 	ti->num_flush_requests = 1;
 	ti->flush_supported = true;
+	ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
 
 	/* In case the pool supports discards, pass them on. */
 	if (tc->pool->pf.discard_enabled) {
@@ -2609,20 +2624,17 @@ out_unlock:
 	return r;
 }
 
-static int thin_map(struct dm_target *ti, struct bio *bio,
-		    union map_info *map_context)
+static int thin_map(struct dm_target *ti, struct bio *bio)
 {
 	bio->bi_sector = dm_target_offset(ti, bio->bi_sector);
 
-	return thin_bio_map(ti, bio, map_context);
+	return thin_bio_map(ti, bio);
 }
 
-static int thin_endio(struct dm_target *ti,
-		      struct bio *bio, int err,
-		      union map_info *map_context)
+static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
 {
 	unsigned long flags;
-	struct dm_thin_endio_hook *h = map_context->ptr;
+	struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 	struct list_head work;
 	struct dm_thin_new_mapping *m, *tmp;
 	struct pool *pool = h->tc->pool;
@@ -2643,14 +2655,15 @@ static int thin_endio(struct dm_target *ti,
 	if (h->all_io_entry) {
 		INIT_LIST_HEAD(&work);
 		dm_deferred_entry_dec(h->all_io_entry, &work);
-		spin_lock_irqsave(&pool->lock, flags);
-		list_for_each_entry_safe(m, tmp, &work, list)
-			list_add(&m->list, &pool->prepared_discards);
-		spin_unlock_irqrestore(&pool->lock, flags);
+		if (!list_empty(&work)) {
+			spin_lock_irqsave(&pool->lock, flags);
+			list_for_each_entry_safe(m, tmp, &work, list)
+				list_add(&m->list, &pool->prepared_discards);
+			spin_unlock_irqrestore(&pool->lock, flags);
+			wake_worker(pool);
+		}
 	}
 
-	mempool_free(h, pool->endio_hook_pool);
-
 	return 0;
 }
 
@@ -2745,7 +2758,7 @@ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
 
 static struct target_type thin_target = {
 	.name = "thin",
-	.version = {1, 5, 0},
+	.version = {1, 6, 0},
 	.module	= THIS_MODULE,
 	.ctr = thin_ctr,
 	.dtr = thin_dtr,
@@ -2779,14 +2792,8 @@ static int __init dm_thin_init(void)
 	if (!_new_mapping_cache)
 		goto bad_new_mapping_cache;
 
-	_endio_hook_cache = KMEM_CACHE(dm_thin_endio_hook, 0);
-	if (!_endio_hook_cache)
-		goto bad_endio_hook_cache;
-
 	return 0;
 
-bad_endio_hook_cache:
-	kmem_cache_destroy(_new_mapping_cache);
 bad_new_mapping_cache:
 	dm_unregister_target(&pool_target);
 bad_pool_target:
@@ -2801,7 +2808,6 @@ static void dm_thin_exit(void)
 	dm_unregister_target(&pool_target);
 
 	kmem_cache_destroy(_new_mapping_cache);
-	kmem_cache_destroy(_endio_hook_cache);
 }
 
 module_init(dm_thin_init);
diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index 9e7328bb403..52cde982164 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -55,7 +55,6 @@ struct dm_verity {
 	unsigned shash_descsize;/* the size of temporary space for crypto */
 	int hash_failed;	/* set to 1 if hash of any block failed */
 
-	mempool_t *io_mempool;	/* mempool of struct dm_verity_io */
 	mempool_t *vec_mempool;	/* mempool of bio vector */
 
 	struct workqueue_struct *verify_wq;
@@ -66,7 +65,6 @@ struct dm_verity {
 
 struct dm_verity_io {
 	struct dm_verity *v;
-	struct bio *bio;
 
 	/* original values of bio->bi_end_io and bio->bi_private */
 	bio_end_io_t *orig_bi_end_io;
@@ -389,8 +387,8 @@ test_block_hash:
  */
 static void verity_finish_io(struct dm_verity_io *io, int error)
 {
-	struct bio *bio = io->bio;
 	struct dm_verity *v = io->v;
+	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size);
 
 	bio->bi_end_io = io->orig_bi_end_io;
 	bio->bi_private = io->orig_bi_private;
@@ -398,8 +396,6 @@ static void verity_finish_io(struct dm_verity_io *io, int error)
 	if (io->io_vec != io->io_vec_inline)
 		mempool_free(io->io_vec, v->vec_mempool);
 
-	mempool_free(io, v->io_mempool);
-
 	bio_endio(bio, error);
 }
 
@@ -462,8 +458,7 @@ no_prefetch_cluster:
  * Bio map function. It allocates dm_verity_io structure and bio vector and
  * fills them. Then it issues prefetches and the I/O.
  */
-static int verity_map(struct dm_target *ti, struct bio *bio,
-		      union map_info *map_context)
+static int verity_map(struct dm_target *ti, struct bio *bio)
 {
 	struct dm_verity *v = ti->private;
 	struct dm_verity_io *io;
@@ -486,9 +481,8 @@ static int verity_map(struct dm_target *ti, struct bio *bio,
 	if (bio_data_dir(bio) == WRITE)
 		return -EIO;
 
-	io = mempool_alloc(v->io_mempool, GFP_NOIO);
+	io = dm_per_bio_data(bio, ti->per_bio_data_size);
 	io->v = v;
-	io->bio = bio;
 	io->orig_bi_end_io = bio->bi_end_io;
 	io->orig_bi_private = bio->bi_private;
 	io->block = bio->bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT);
@@ -610,9 +604,6 @@ static void verity_dtr(struct dm_target *ti)
 	if (v->vec_mempool)
 		mempool_destroy(v->vec_mempool);
 
-	if (v->io_mempool)
-		mempool_destroy(v->io_mempool);
-
 	if (v->bufio)
 		dm_bufio_client_destroy(v->bufio);
 
@@ -841,13 +832,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		goto bad;
 	}
 
-	v->io_mempool = mempool_create_kmalloc_pool(DM_VERITY_MEMPOOL_SIZE,
-	  sizeof(struct dm_verity_io) + v->shash_descsize + v->digest_size * 2);
-	if (!v->io_mempool) {
-		ti->error = "Cannot allocate io mempool";
-		r = -ENOMEM;
-		goto bad;
-	}
+	ti->per_bio_data_size = roundup(sizeof(struct dm_verity_io) + v->shash_descsize + v->digest_size * 2, __alignof__(struct dm_verity_io));
 
 	v->vec_mempool = mempool_create_kmalloc_pool(DM_VERITY_MEMPOOL_SIZE,
 					BIO_MAX_PAGES * sizeof(struct bio_vec));
@@ -875,7 +860,7 @@ bad:
 
 static struct target_type verity_target = {
 	.name		= "verity",
-	.version	= {1, 0, 0},
+	.version	= {1, 1, 0},
 	.module		= THIS_MODULE,
 	.ctr		= verity_ctr,
 	.dtr		= verity_dtr,
diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
index cc2b3cb8194..69a5c3b3b34 100644
--- a/drivers/md/dm-zero.c
+++ b/drivers/md/dm-zero.c
@@ -33,8 +33,7 @@ static int zero_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 /*
  * Return zeros only on reads
  */
-static int zero_map(struct dm_target *ti, struct bio *bio,
-		      union map_info *map_context)
+static int zero_map(struct dm_target *ti, struct bio *bio)
 {
 	switch(bio_rw(bio)) {
 	case READ:
@@ -56,7 +55,7 @@ static int zero_map(struct dm_target *ti, struct bio *bio,
 
 static struct target_type zero_target = {
 	.name   = "zero",
-	.version = {1, 0, 0},
+	.version = {1, 1, 0},
 	.module = THIS_MODULE,
 	.ctr    = zero_ctr,
 	.map    = zero_map,
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 77e6eff41ca..c72e4d5a961 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -63,18 +63,6 @@ struct dm_io {
 };
 
 /*
- * For bio-based dm.
- * One of these is allocated per target within a bio.  Hopefully
- * this will be simplified out one day.
- */
-struct dm_target_io {
-	struct dm_io *io;
-	struct dm_target *ti;
-	union map_info info;
-	struct bio clone;
-};
-
-/*
  * For request-based dm.
  * One of these is allocated per request.
  */
@@ -657,7 +645,7 @@ static void clone_endio(struct bio *bio, int error)
 		error = -EIO;
 
 	if (endio) {
-		r = endio(tio->ti, bio, error, &tio->info);
+		r = endio(tio->ti, bio, error);
 		if (r < 0 || r == DM_ENDIO_REQUEUE)
 			/*
 			 * error and requeue request are handled
@@ -1016,7 +1004,7 @@ static void __map_bio(struct dm_target *ti, struct dm_target_io *tio)
 	 */
 	atomic_inc(&tio->io->io_count);
 	sector = clone->bi_sector;
-	r = ti->type->map(ti, clone, &tio->info);
+	r = ti->type->map(ti, clone);
 	if (r == DM_MAPIO_REMAPPED) {
 		/* the bio has been remapped so dispatch it */
 
@@ -1111,6 +1099,7 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci,
 	tio->io = ci->io;
 	tio->ti = ti;
 	memset(&tio->info, 0, sizeof(tio->info));
+	tio->target_request_nr = 0;
 
 	return tio;
 }
@@ -1121,7 +1110,7 @@ static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
 	struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs);
 	struct bio *clone = &tio->clone;
 
-	tio->info.target_request_nr = request_nr;
+	tio->target_request_nr = request_nr;
 
 	/*
 	 * Discard requests require the bio's inline iovecs be initialized.
@@ -1174,7 +1163,28 @@ static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
 	ci->sector_count = 0;
 }
 
-static int __clone_and_map_discard(struct clone_info *ci)
+typedef unsigned (*get_num_requests_fn)(struct dm_target *ti);
+
+static unsigned get_num_discard_requests(struct dm_target *ti)
+{
+	return ti->num_discard_requests;
+}
+
+static unsigned get_num_write_same_requests(struct dm_target *ti)
+{
+	return ti->num_write_same_requests;
+}
+
+typedef bool (*is_split_required_fn)(struct dm_target *ti);
+
+static bool is_split_required_for_discard(struct dm_target *ti)
+{
+	return ti->split_discard_requests;
+}
+
+static int __clone_and_map_changing_extent_only(struct clone_info *ci,
+						get_num_requests_fn get_num_requests,
+						is_split_required_fn is_split_required)
 {
 	struct dm_target *ti;
 	sector_t len;
@@ -1185,15 +1195,15 @@ static int __clone_and_map_discard(struct clone_info *ci)
 			return -EIO;
 
 		/*
-		 * Even though the device advertised discard support,
-		 * that does not mean every target supports it, and
+		 * Even though the device advertised support for this type of
+		 * request, that does not mean every target supports it, and
 		 * reconfiguration might also have changed that since the
 		 * check was performed.
 		 */
-		if (!ti->num_discard_requests)
+		if (!get_num_requests || !get_num_requests(ti))
 			return -EOPNOTSUPP;
 
-		if (!ti->split_discard_requests)
+		if (is_split_required && !is_split_required(ti))
 			len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
 		else
 			len = min(ci->sector_count, max_io_len(ci->sector, ti));
@@ -1206,6 +1216,17 @@ static int __clone_and_map_discard(struct clone_info *ci)
 	return 0;
 }
 
+static int __clone_and_map_discard(struct clone_info *ci)
+{
+	return __clone_and_map_changing_extent_only(ci, get_num_discard_requests,
+						    is_split_required_for_discard);
+}
+
+static int __clone_and_map_write_same(struct clone_info *ci)
+{
+	return __clone_and_map_changing_extent_only(ci, get_num_write_same_requests, NULL);
+}
+
 static int __clone_and_map(struct clone_info *ci)
 {
 	struct bio *bio = ci->bio;
@@ -1215,6 +1236,8 @@ static int __clone_and_map(struct clone_info *ci)
 
 	if (unlikely(bio->bi_rw & REQ_DISCARD))
 		return __clone_and_map_discard(ci);
+	else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
+		return __clone_and_map_write_same(ci);
 
 	ti = dm_table_find_target(ci->map, ci->sector);
 	if (!dm_target_is_valid(ti))
@@ -1946,13 +1969,20 @@ static void free_dev(struct mapped_device *md)
 
 static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
 {
-	struct dm_md_mempools *p;
+	struct dm_md_mempools *p = dm_table_get_md_mempools(t);
 
-	if (md->io_pool && (md->tio_pool || dm_table_get_type(t) == DM_TYPE_BIO_BASED) && md->bs)
-		/* the md already has necessary mempools */
+	if (md->io_pool && (md->tio_pool || dm_table_get_type(t) == DM_TYPE_BIO_BASED) && md->bs) {
+		/*
+		 * The md already has necessary mempools. Reload just the
+		 * bioset because front_pad may have changed because
+		 * a different table was loaded.
+		 */
+		bioset_free(md->bs);
+		md->bs = p->bs;
+		p->bs = NULL;
 		goto out;
+	}
 
-	p = dm_table_get_md_mempools(t);
 	BUG_ON(!p || md->io_pool || md->tio_pool || md->bs);
 
 	md->io_pool = p->io_pool;
@@ -2711,7 +2741,7 @@ int dm_noflush_suspending(struct dm_target *ti)
 }
 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
 
-struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity)
+struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size)
 {
 	struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
 	unsigned int pool_size = (type == DM_TYPE_BIO_BASED) ? 16 : MIN_IOS;
@@ -2719,6 +2749,8 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity)
 	if (!pools)
 		return NULL;
 
+	per_bio_data_size = roundup(per_bio_data_size, __alignof__(struct dm_target_io));
+
 	pools->io_pool = (type == DM_TYPE_BIO_BASED) ?
 			 mempool_create_slab_pool(MIN_IOS, _io_cache) :
 			 mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache);
@@ -2734,7 +2766,7 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity)
 
 	pools->bs = (type == DM_TYPE_BIO_BASED) ?
 		bioset_create(pool_size,
-			      offsetof(struct dm_target_io, clone)) :
+			      per_bio_data_size + offsetof(struct dm_target_io, clone)) :
 		bioset_create(pool_size,
 			      offsetof(struct dm_rq_clone_bio_info, clone));
 	if (!pools->bs)
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 6a99fefaa74..45b97da1bd0 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -159,7 +159,7 @@ void dm_kcopyd_exit(void);
 /*
  * Mempool operations
  */
-struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity);
+struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size);
 void dm_free_md_mempools(struct dm_md_mempools *pools);
 
 #endif
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index a3ae09124a6..28c3ed072a7 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -428,15 +428,17 @@ static int dm_bm_validate_buffer(struct dm_block_manager *bm,
 		if (!v)
 			return 0;
 		r = v->check(v, (struct dm_block *) buf, dm_bufio_get_block_size(bm->bufio));
-		if (unlikely(r))
+		if (unlikely(r)) {
+			DMERR_LIMIT("%s validator check failed for block %llu", v->name,
+				    (unsigned long long) dm_bufio_get_block_number(buf));
 			return r;
+		}
 		aux->validator = v;
 	} else {
 		if (unlikely(aux->validator != v)) {
-			DMERR("validator mismatch (old=%s vs new=%s) for block %llu",
-				aux->validator->name, v ? v->name : "NULL",
-				(unsigned long long)
-					dm_bufio_get_block_number(buf));
+			DMERR_LIMIT("validator mismatch (old=%s vs new=%s) for block %llu",
+				    aux->validator->name, v ? v->name : "NULL",
+				    (unsigned long long) dm_bufio_get_block_number(buf));
 			return -EINVAL;
 		}
 	}
diff --git a/drivers/md/persistent-data/dm-btree-internal.h b/drivers/md/persistent-data/dm-btree-internal.h
index 5709bfeab1e..accbb05f17b 100644
--- a/drivers/md/persistent-data/dm-btree-internal.h
+++ b/drivers/md/persistent-data/dm-btree-internal.h
@@ -36,13 +36,13 @@ struct node_header {
 	__le32 padding;
 } __packed;
 
-struct node {
+struct btree_node {
 	struct node_header header;
 	__le64 keys[0];
 } __packed;
 
 
-void inc_children(struct dm_transaction_manager *tm, struct node *n,
+void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
 		  struct dm_btree_value_type *vt);
 
 int new_block(struct dm_btree_info *info, struct dm_block **result);
@@ -64,7 +64,7 @@ struct ro_spine {
 void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
 int exit_ro_spine(struct ro_spine *s);
 int ro_step(struct ro_spine *s, dm_block_t new_child);
-struct node *ro_node(struct ro_spine *s);
+struct btree_node *ro_node(struct ro_spine *s);
 
 struct shadow_spine {
 	struct dm_btree_info *info;
@@ -98,17 +98,17 @@ int shadow_root(struct shadow_spine *s);
 /*
  * Some inlines.
  */
-static inline __le64 *key_ptr(struct node *n, uint32_t index)
+static inline __le64 *key_ptr(struct btree_node *n, uint32_t index)
 {
 	return n->keys + index;
 }
 
-static inline void *value_base(struct node *n)
+static inline void *value_base(struct btree_node *n)
 {
 	return &n->keys[le32_to_cpu(n->header.max_entries)];
 }
 
-static inline void *value_ptr(struct node *n, uint32_t index)
+static inline void *value_ptr(struct btree_node *n, uint32_t index)
 {
 	uint32_t value_size = le32_to_cpu(n->header.value_size);
 	return value_base(n) + (value_size * index);
@@ -117,7 +117,7 @@ static inline void *value_ptr(struct node *n, uint32_t index)
 /*
  * Assumes the values are suitably-aligned and converts to core format.
  */
-static inline uint64_t value64(struct node *n, uint32_t index)
+static inline uint64_t value64(struct btree_node *n, uint32_t index)
 {
 	__le64 *values_le = value_base(n);
 
@@ -127,7 +127,7 @@ static inline uint64_t value64(struct node *n, uint32_t index)
 /*
  * Searching for a key within a single node.
  */
-int lower_bound(struct node *n, uint64_t key);
+int lower_bound(struct btree_node *n, uint64_t key);
 
 extern struct dm_block_validator btree_node_validator;
 
diff --git a/drivers/md/persistent-data/dm-btree-remove.c b/drivers/md/persistent-data/dm-btree-remove.c
index aa71e2359a0..c4f28133ef8 100644
--- a/drivers/md/persistent-data/dm-btree-remove.c
+++ b/drivers/md/persistent-data/dm-btree-remove.c
@@ -53,7 +53,7 @@
 /*
  * Some little utilities for moving node data around.
  */
-static void node_shift(struct node *n, int shift)
+static void node_shift(struct btree_node *n, int shift)
 {
 	uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
 	uint32_t value_size = le32_to_cpu(n->header.value_size);
@@ -79,7 +79,7 @@ static void node_shift(struct node *n, int shift)
 	}
 }
 
-static void node_copy(struct node *left, struct node *right, int shift)
+static void node_copy(struct btree_node *left, struct btree_node *right, int shift)
 {
 	uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
 	uint32_t value_size = le32_to_cpu(left->header.value_size);
@@ -108,7 +108,7 @@ static void node_copy(struct node *left, struct node *right, int shift)
 /*
  * Delete a specific entry from a leaf node.
  */
-static void delete_at(struct node *n, unsigned index)
+static void delete_at(struct btree_node *n, unsigned index)
 {
 	unsigned nr_entries = le32_to_cpu(n->header.nr_entries);
 	unsigned nr_to_copy = nr_entries - (index + 1);
@@ -128,7 +128,7 @@ static void delete_at(struct node *n, unsigned index)
 	n->header.nr_entries = cpu_to_le32(nr_entries - 1);
 }
 
-static unsigned merge_threshold(struct node *n)
+static unsigned merge_threshold(struct btree_node *n)
 {
 	return le32_to_cpu(n->header.max_entries) / 3;
 }
@@ -136,7 +136,7 @@ static unsigned merge_threshold(struct node *n)
 struct child {
 	unsigned index;
 	struct dm_block *block;
-	struct node *n;
+	struct btree_node *n;
 };
 
 static struct dm_btree_value_type le64_type = {
@@ -147,7 +147,7 @@ static struct dm_btree_value_type le64_type = {
 	.equal = NULL
 };
 
-static int init_child(struct dm_btree_info *info, struct node *parent,
+static int init_child(struct dm_btree_info *info, struct btree_node *parent,
 		      unsigned index, struct child *result)
 {
 	int r, inc;
@@ -177,7 +177,7 @@ static int exit_child(struct dm_btree_info *info, struct child *c)
 	return dm_tm_unlock(info->tm, c->block);
 }
 
-static void shift(struct node *left, struct node *right, int count)
+static void shift(struct btree_node *left, struct btree_node *right, int count)
 {
 	uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
 	uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
@@ -203,11 +203,11 @@ static void shift(struct node *left, struct node *right, int count)
 	right->header.nr_entries = cpu_to_le32(nr_right + count);
 }
 
-static void __rebalance2(struct dm_btree_info *info, struct node *parent,
+static void __rebalance2(struct dm_btree_info *info, struct btree_node *parent,
 			 struct child *l, struct child *r)
 {
-	struct node *left = l->n;
-	struct node *right = r->n;
+	struct btree_node *left = l->n;
+	struct btree_node *right = r->n;
 	uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
 	uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
 	unsigned threshold = 2 * merge_threshold(left) + 1;
@@ -239,7 +239,7 @@ static int rebalance2(struct shadow_spine *s, struct dm_btree_info *info,
 		      unsigned left_index)
 {
 	int r;
-	struct node *parent;
+	struct btree_node *parent;
 	struct child left, right;
 
 	parent = dm_block_data(shadow_current(s));
@@ -270,9 +270,9 @@ static int rebalance2(struct shadow_spine *s, struct dm_btree_info *info,
  * in right, then rebalance2.  This wastes some cpu, but I want something
  * simple atm.
  */
-static void delete_center_node(struct dm_btree_info *info, struct node *parent,
+static void delete_center_node(struct dm_btree_info *info, struct btree_node *parent,
 			       struct child *l, struct child *c, struct child *r,
-			       struct node *left, struct node *center, struct node *right,
+			       struct btree_node *left, struct btree_node *center, struct btree_node *right,
 			       uint32_t nr_left, uint32_t nr_center, uint32_t nr_right)
 {
 	uint32_t max_entries = le32_to_cpu(left->header.max_entries);
@@ -301,9 +301,9 @@ static void delete_center_node(struct dm_btree_info *info, struct node *parent,
 /*
  * Redistributes entries among 3 sibling nodes.
  */
-static void redistribute3(struct dm_btree_info *info, struct node *parent,
+static void redistribute3(struct dm_btree_info *info, struct btree_node *parent,
 			  struct child *l, struct child *c, struct child *r,
-			  struct node *left, struct node *center, struct node *right,
+			  struct btree_node *left, struct btree_node *center, struct btree_node *right,
 			  uint32_t nr_left, uint32_t nr_center, uint32_t nr_right)
 {
 	int s;
@@ -343,12 +343,12 @@ static void redistribute3(struct dm_btree_info *info, struct node *parent,
 	*key_ptr(parent, r->index) = right->keys[0];
 }
 
-static void __rebalance3(struct dm_btree_info *info, struct node *parent,
+static void __rebalance3(struct dm_btree_info *info, struct btree_node *parent,
 			 struct child *l, struct child *c, struct child *r)
 {
-	struct node *left = l->n;
-	struct node *center = c->n;
-	struct node *right = r->n;
+	struct btree_node *left = l->n;
+	struct btree_node *center = c->n;
+	struct btree_node *right = r->n;
 
 	uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
 	uint32_t nr_center = le32_to_cpu(center->header.nr_entries);
@@ -371,7 +371,7 @@ static int rebalance3(struct shadow_spine *s, struct dm_btree_info *info,
 		      unsigned left_index)
 {
 	int r;
-	struct node *parent = dm_block_data(shadow_current(s));
+	struct btree_node *parent = dm_block_data(shadow_current(s));
 	struct child left, center, right;
 
 	/*
@@ -421,7 +421,7 @@ static int get_nr_entries(struct dm_transaction_manager *tm,
 {
 	int r;
 	struct dm_block *block;
-	struct node *n;
+	struct btree_node *n;
 
 	r = dm_tm_read_lock(tm, b, &btree_node_validator, &block);
 	if (r)
@@ -438,7 +438,7 @@ static int rebalance_children(struct shadow_spine *s,
 {
 	int i, r, has_left_sibling, has_right_sibling;
 	uint32_t child_entries;
-	struct node *n;
+	struct btree_node *n;
 
 	n = dm_block_data(shadow_current(s));
 
@@ -483,7 +483,7 @@ static int rebalance_children(struct shadow_spine *s,
 	return r;
 }
 
-static int do_leaf(struct node *n, uint64_t key, unsigned *index)
+static int do_leaf(struct btree_node *n, uint64_t key, unsigned *index)
 {
 	int i = lower_bound(n, key);
 
@@ -506,7 +506,7 @@ static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
 		      uint64_t key, unsigned *index)
 {
 	int i = *index, r;
-	struct node *n;
+	struct btree_node *n;
 
 	for (;;) {
 		r = shadow_step(s, root, vt);
@@ -556,7 +556,7 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
 	unsigned level, last_level = info->levels - 1;
 	int index = 0, r = 0;
 	struct shadow_spine spine;
-	struct node *n;
+	struct btree_node *n;
 
 	init_shadow_spine(&spine, info);
 	for (level = 0; level < info->levels; level++) {
diff --git a/drivers/md/persistent-data/dm-btree-spine.c b/drivers/md/persistent-data/dm-btree-spine.c
index d9a7912ee8e..f199a0c4ed0 100644
--- a/drivers/md/persistent-data/dm-btree-spine.c
+++ b/drivers/md/persistent-data/dm-btree-spine.c
@@ -23,7 +23,7 @@ static void node_prepare_for_write(struct dm_block_validator *v,
 				   struct dm_block *b,
 				   size_t block_size)
 {
-	struct node *n = dm_block_data(b);
+	struct btree_node *n = dm_block_data(b);
 	struct node_header *h = &n->header;
 
 	h->blocknr = cpu_to_le64(dm_block_location(b));
@@ -38,15 +38,15 @@ static int node_check(struct dm_block_validator *v,
 		      struct dm_block *b,
 		      size_t block_size)
 {
-	struct node *n = dm_block_data(b);
+	struct btree_node *n = dm_block_data(b);
 	struct node_header *h = &n->header;
 	size_t value_size;
 	__le32 csum_disk;
 	uint32_t flags;
 
 	if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
-		DMERR("node_check failed blocknr %llu wanted %llu",
-		      le64_to_cpu(h->blocknr), dm_block_location(b));
+		DMERR_LIMIT("node_check failed: blocknr %llu != wanted %llu",
+			    le64_to_cpu(h->blocknr), dm_block_location(b));
 		return -ENOTBLK;
 	}
 
@@ -54,8 +54,8 @@ static int node_check(struct dm_block_validator *v,
 					       block_size - sizeof(__le32),
 					       BTREE_CSUM_XOR));
 	if (csum_disk != h->csum) {
-		DMERR("node_check failed csum %u wanted %u",
-		      le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
+		DMERR_LIMIT("node_check failed: csum %u != wanted %u",
+			    le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
 		return -EILSEQ;
 	}
 
@@ -63,12 +63,12 @@ static int node_check(struct dm_block_validator *v,
 
 	if (sizeof(struct node_header) +
 	    (sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) {
-		DMERR("node_check failed: max_entries too large");
+		DMERR_LIMIT("node_check failed: max_entries too large");
 		return -EILSEQ;
 	}
 
 	if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) {
-		DMERR("node_check failed, too many entries");
+		DMERR_LIMIT("node_check failed: too many entries");
 		return -EILSEQ;
 	}
 
@@ -77,7 +77,7 @@ static int node_check(struct dm_block_validator *v,
 	 */
 	flags = le32_to_cpu(h->flags);
 	if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
-		DMERR("node_check failed, node is neither INTERNAL or LEAF");
+		DMERR_LIMIT("node_check failed: node is neither INTERNAL or LEAF");
 		return -EILSEQ;
 	}
 
@@ -164,7 +164,7 @@ int ro_step(struct ro_spine *s, dm_block_t new_child)
 	return r;
 }
 
-struct node *ro_node(struct ro_spine *s)
+struct btree_node *ro_node(struct ro_spine *s)
 {
 	struct dm_block *block;
 
diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
index d12b2cc51f1..4caf66918cd 100644
--- a/drivers/md/persistent-data/dm-btree.c
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -38,7 +38,7 @@ static void array_insert(void *base, size_t elt_size, unsigned nr_elts,
 /*----------------------------------------------------------------*/
 
 /* makes the assumption that no two keys are the same. */
-static int bsearch(struct node *n, uint64_t key, int want_hi)
+static int bsearch(struct btree_node *n, uint64_t key, int want_hi)
 {
 	int lo = -1, hi = le32_to_cpu(n->header.nr_entries);
 
@@ -58,12 +58,12 @@ static int bsearch(struct node *n, uint64_t key, int want_hi)
 	return want_hi ? hi : lo;
 }
 
-int lower_bound(struct node *n, uint64_t key)
+int lower_bound(struct btree_node *n, uint64_t key)
 {
 	return bsearch(n, key, 0);
 }
 
-void inc_children(struct dm_transaction_manager *tm, struct node *n,
+void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
 		  struct dm_btree_value_type *vt)
 {
 	unsigned i;
@@ -77,7 +77,7 @@ void inc_children(struct dm_transaction_manager *tm, struct node *n,
 			vt->inc(vt->context, value_ptr(n, i));
 }
 
-static int insert_at(size_t value_size, struct node *node, unsigned index,
+static int insert_at(size_t value_size, struct btree_node *node, unsigned index,
 		      uint64_t key, void *value)
 		      __dm_written_to_disk(value)
 {
@@ -122,7 +122,7 @@ int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root)
 {
 	int r;
 	struct dm_block *b;
-	struct node *n;
+	struct btree_node *n;
 	size_t block_size;
 	uint32_t max_entries;
 
@@ -154,7 +154,7 @@ EXPORT_SYMBOL_GPL(dm_btree_empty);
 #define MAX_SPINE_DEPTH 64
 struct frame {
 	struct dm_block *b;
-	struct node *n;
+	struct btree_node *n;
 	unsigned level;
 	unsigned nr_children;
 	unsigned current_child;
@@ -230,6 +230,11 @@ static void pop_frame(struct del_stack *s)
 	dm_tm_unlock(s->tm, f->b);
 }
 
+static bool is_internal_level(struct dm_btree_info *info, struct frame *f)
+{
+	return f->level < (info->levels - 1);
+}
+
 int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
 {
 	int r;
@@ -241,7 +246,7 @@ int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
 	s->tm = info->tm;
 	s->top = -1;
 
-	r = push_frame(s, root, 1);
+	r = push_frame(s, root, 0);
 	if (r)
 		goto out;
 
@@ -267,7 +272,7 @@ int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
 			if (r)
 				goto out;
 
-		} else if (f->level != (info->levels - 1)) {
+		} else if (is_internal_level(info, f)) {
 			b = value64(f->n, f->current_child);
 			f->current_child++;
 			r = push_frame(s, b, f->level + 1);
@@ -295,7 +300,7 @@ EXPORT_SYMBOL_GPL(dm_btree_del);
 /*----------------------------------------------------------------*/
 
 static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key,
-			    int (*search_fn)(struct node *, uint64_t),
+			    int (*search_fn)(struct btree_node *, uint64_t),
 			    uint64_t *result_key, void *v, size_t value_size)
 {
 	int i, r;
@@ -406,7 +411,7 @@ static int btree_split_sibling(struct shadow_spine *s, dm_block_t root,
 	size_t size;
 	unsigned nr_left, nr_right;
 	struct dm_block *left, *right, *parent;
-	struct node *ln, *rn, *pn;
+	struct btree_node *ln, *rn, *pn;
 	__le64 location;
 
 	left = shadow_current(s);
@@ -491,7 +496,7 @@ static int btree_split_beneath(struct shadow_spine *s, uint64_t key)
 	size_t size;
 	unsigned nr_left, nr_right;
 	struct dm_block *left, *right, *new_parent;
-	struct node *pn, *ln, *rn;
+	struct btree_node *pn, *ln, *rn;
 	__le64 val;
 
 	new_parent = shadow_current(s);
@@ -576,7 +581,7 @@ static int btree_insert_raw(struct shadow_spine *s, dm_block_t root,
 			    uint64_t key, unsigned *index)
 {
 	int r, i = *index, top = 1;
-	struct node *node;
+	struct btree_node *node;
 
 	for (;;) {
 		r = shadow_step(s, root, vt);
@@ -643,7 +648,7 @@ static int insert(struct dm_btree_info *info, dm_block_t root,
 	unsigned level, index = -1, last_level = info->levels - 1;
 	dm_block_t block = root;
 	struct shadow_spine spine;
-	struct node *n;
+	struct btree_node *n;
 	struct dm_btree_value_type le64_type;
 
 	le64_type.context = NULL;
diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c
index f3a9af8cdec..3e7a88d99eb 100644
--- a/drivers/md/persistent-data/dm-space-map-common.c
+++ b/drivers/md/persistent-data/dm-space-map-common.c
@@ -39,8 +39,8 @@ static int index_check(struct dm_block_validator *v,
 	__le32 csum_disk;
 
 	if (dm_block_location(b) != le64_to_cpu(mi_le->blocknr)) {
-		DMERR("index_check failed blocknr %llu wanted %llu",
-		      le64_to_cpu(mi_le->blocknr), dm_block_location(b));
+		DMERR_LIMIT("index_check failed: blocknr %llu != wanted %llu",
+			    le64_to_cpu(mi_le->blocknr), dm_block_location(b));
 		return -ENOTBLK;
 	}
 
@@ -48,8 +48,8 @@ static int index_check(struct dm_block_validator *v,
 					       block_size - sizeof(__le32),
 					       INDEX_CSUM_XOR));
 	if (csum_disk != mi_le->csum) {
-		DMERR("index_check failed csum %u wanted %u",
-		      le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum));
+		DMERR_LIMIT("index_check failed: csum %u != wanted %u",
+			    le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum));
 		return -EILSEQ;
 	}
 
@@ -89,8 +89,8 @@ static int bitmap_check(struct dm_block_validator *v,
 	__le32 csum_disk;
 
 	if (dm_block_location(b) != le64_to_cpu(disk_header->blocknr)) {
-		DMERR("bitmap check failed blocknr %llu wanted %llu",
-		      le64_to_cpu(disk_header->blocknr), dm_block_location(b));
+		DMERR_LIMIT("bitmap check failed: blocknr %llu != wanted %llu",
+			    le64_to_cpu(disk_header->blocknr), dm_block_location(b));
 		return -ENOTBLK;
 	}
 
@@ -98,8 +98,8 @@ static int bitmap_check(struct dm_block_validator *v,
 					       block_size - sizeof(__le32),
 					       BITMAP_CSUM_XOR));
 	if (csum_disk != disk_header->csum) {
-		DMERR("bitmap check failed csum %u wanted %u",
-		      le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum));
+		DMERR_LIMIT("bitmap check failed: csum %u != wanted %u",
+			    le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum));
 		return -EILSEQ;
 	}
 
diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index e89ae5e7a51..906cf3df71a 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -337,7 +337,7 @@ static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
 {
 	int r = sm_metadata_new_block_(sm, b);
 	if (r)
-		DMERR("out of metadata space");
+		DMERR("unable to allocate new metadata block");
 	return r;
 }