Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: (48 commits)
  dm mpath: change to be request based
  dm: disable interrupt when taking map_lock
  dm: do not set QUEUE_ORDERED_DRAIN if request based
  dm: enable request based option
  dm: prepare for request based option
  dm raid1: add userspace log
  dm: calculate queue limits during resume not load
  dm log: fix create_log_context to use logical_block_size of log device
  dm target:s introduce iterate devices fn
  dm table: establish queue limits by copying table limits
  dm table: replace struct io_restrictions with struct queue_limits
  dm table: validate device logical_block_size
  dm table: ensure targets are aligned to logical_block_size
  dm ioctl: support cookies for udev
  dm: sysfs add suspended attribute
  dm table: improve warning message when devices not freed before destruction
  dm mpath: add service time load balancer
  dm mpath: add queue length load balancer
  dm mpath: add start_io and nr_bytes to path selectors
  dm snapshot: use barrier when writing exception store
  ...

Documentation/device-mapper/dm-log.txt

+Device-Mapper Logging
+=====================
+The device-mapper logging code is used by some of the device-mapper
+RAID targets to track regions of the disk that are not consistent.
+A region (or portion of the address space) of the disk may be
+inconsistent because a RAID stripe is currently being operated on or
+a machine died while the region was being altered.  In the case of
+mirrors, a region would be considered dirty/inconsistent while you
+are writing to it because the writes need to be replicated for all
+the legs of the mirror and may not reach the legs at the same time.
+Once all writes are complete, the region is considered clean again.
+
+There is a generic logging interface that the device-mapper RAID
+implementations use to perform logging operations (see
+dm_dirty_log_type in include/linux/dm-dirty-log.h).  Various different
+logging implementations are available and provide different
+capabilities.  The list includes:
+
+Type		Files
+====		=====
+disk		drivers/md/dm-log.c
+core		drivers/md/dm-log.c
+userspace	drivers/md/dm-log-userspace* include/linux/dm-log-userspace.h
+
+The "disk" log type
+-------------------
+This log implementation commits the log state to disk.  This way, the
+logging state survives reboots/crashes.
+
+The "core" log type
+-------------------
+This log implementation keeps the log state in memory.  The log state
+will not survive a reboot or crash, but there may be a small boost in
+performance.  This method can also be used if no storage device is
+available for storing log state.
+
+The "userspace" log type
+------------------------
+This log type simply provides a way to export the log API to userspace,
+so log implementations can be done there.  This is done by forwarding most
+logging requests to userspace, where a daemon receives and processes the
+request.
+
+The structure used for communication between kernel and userspace are
+located in include/linux/dm-log-userspace.h.  Due to the frequency,
+diversity, and 2-way communication nature of the exchanges between
+kernel and userspace, 'connector' is used as the interface for
+communication.
+
+There are currently two userspace log implementations that leverage this
+framework - "clustered_disk" and "clustered_core".  These implementations
+provide a cluster-coherent log for shared-storage.  Device-mapper mirroring
+can be used in a shared-storage environment when the cluster log implementations
+are employed.

Documentation/device-mapper/dm-queue-length.txt

+dm-queue-length
+===============
+
+dm-queue-length is a path selector module for device-mapper targets,
+which selects a path with the least number of in-flight I/Os.
+The path selector name is 'queue-length'.
+
+Table parameters for each path: [<repeat_count>]
+	<repeat_count>: The number of I/Os to dispatch using the selected
+			path before switching to the next path.
+			If not given, internal default is used. To check
+			the default value, see the activated table.
+
+Status for each path: <status> <fail-count> <in-flight>
+	<status>: 'A' if the path is active, 'F' if the path is failed.
+	<fail-count>: The number of path failures.
+	<in-flight>: The number of in-flight I/Os on the path.
+
+
+Algorithm
+=========
+
+dm-queue-length increments/decrements 'in-flight' when an I/O is
+dispatched/completed respectively.
+dm-queue-length selects a path with the minimum 'in-flight'.
+
+
+Examples
+========
+In case that 2 paths (sda and sdb) are used with repeat_count == 128.
+
+# echo "0 10 multipath 0 0 1 1 queue-length 0 2 1 8:0 128 8:16 128" \
+  dmsetup create test
+#
+# dmsetup table
+test: 0 10 multipath 0 0 1 1 queue-length 0 2 1 8:0 128 8:16 128
+#
+# dmsetup status
+test: 0 10 multipath 2 0 0 0 1 1 E 0 2 1 8:0 A 0 0 8:16 A 0 0

Documentation/device-mapper/dm-service-time.txt

+dm-service-time
+===============
+
+dm-service-time is a path selector module for device-mapper targets,
+which selects a path with the shortest estimated service time for
+the incoming I/O.
+
+The service time for each path is estimated by dividing the total size
+of in-flight I/Os on a path with the performance value of the path.
+The performance value is a relative throughput value among all paths
+in a path-group, and it can be specified as a table argument.
+
+The path selector name is 'service-time'.
+
+Table parameters for each path: [<repeat_count> [<relative_throughput>]]
+	<repeat_count>: The number of I/Os to dispatch using the selected
+			path before switching to the next path.
+			If not given, internal default is used.  To check
+			the default value, see the activated table.
+	<relative_throughput>: The relative throughput value of the path
+			among all paths in the path-group.
+			The valid range is 0-100.
+			If not given, minimum value '1' is used.
+			If '0' is given, the path isn't selected while
+			other paths having a positive value are available.
+
+Status for each path: <status> <fail-count> <in-flight-size> \
+		      <relative_throughput>
+	<status>: 'A' if the path is active, 'F' if the path is failed.
+	<fail-count>: The number of path failures.
+	<in-flight-size>: The size of in-flight I/Os on the path.
+	<relative_throughput>: The relative throughput value of the path
+			among all paths in the path-group.
+
+
+Algorithm
+=========
+
+dm-service-time adds the I/O size to 'in-flight-size' when the I/O is
+dispatched and substracts when completed.
+Basically, dm-service-time selects a path having minimum service time
+which is calculated by:
+
+	('in-flight-size' + 'size-of-incoming-io') / 'relative_throughput'
+
+However, some optimizations below are used to reduce the calculation
+as much as possible.
+
+	1. If the paths have the same 'relative_throughput', skip
+	   the division and just compare the 'in-flight-size'.
+
+	2. If the paths have the same 'in-flight-size', skip the division
+	   and just compare the 'relative_throughput'.
+
+	3. If some paths have non-zero 'relative_throughput' and others
+	   have zero 'relative_throughput', ignore those paths with zero
+	   'relative_throughput'.
+
+If such optimizations can't be applied, calculate service time, and
+compare service time.
+If calculated service time is equal, the path having maximum
+'relative_throughput' may be better.  So compare 'relative_throughput'
+then.
+
+
+Examples
+========
+In case that 2 paths (sda and sdb) are used with repeat_count == 128
+and sda has an average throughput 1GB/s and sdb has 4GB/s,
+'relative_throughput' value may be '1' for sda and '4' for sdb.
+
+# echo "0 10 multipath 0 0 1 1 service-time 0 2 2 8:0 128 1 8:16 128 4" \
+  dmsetup create test
+#
+# dmsetup table
+test: 0 10 multipath 0 0 1 1 service-time 0 2 2 8:0 128 1 8:16 128 4
+#
+# dmsetup status
+test: 0 10 multipath 2 0 0 0 1 1 E 0 2 2 8:0 A 0 0 1 8:16 A 0 0 4
+
+
+Or '2' for sda and '8' for sdb would be also true.
+
+# echo "0 10 multipath 0 0 1 1 service-time 0 2 2 8:0 128 2 8:16 128 8" \
+  dmsetup create test
+#
+# dmsetup table
+test: 0 10 multipath 0 0 1 1 service-time 0 2 2 8:0 128 2 8:16 128 8
+#
+# dmsetup status
+test: 0 10 multipath 2 0 0 0 1 1 E 0 2 2 8:0 A 0 0 2 8:16 A 0 0 8

drivers/md/Kconfig

@@ -231,6 +231,17 @@ config DM_MIRROR
          Allow volume managers to mirror logical volumes, also
          needed for live data migration tools such as 'pvmove'.
 
+config DM_LOG_USERSPACE
+	tristate "Mirror userspace logging (EXPERIMENTAL)"
+	depends on DM_MIRROR && EXPERIMENTAL && NET
+	select CONNECTOR
+	---help---
+	  The userspace logging module provides a mechanism for
+	  relaying the dm-dirty-log API to userspace.  Log designs
+	  which are more suited to userspace implementation (e.g.
+	  shared storage logs) or experimental logs can be implemented
+	  by leveraging this framework.
+
 config DM_ZERO
 	tristate "Zero target"
 	depends on BLK_DEV_DM
@@ -249,6 +260,25 @@ config DM_MULTIPATH
 	---help---
 	  Allow volume managers to support multipath hardware.
 
+config DM_MULTIPATH_QL
+	tristate "I/O Path Selector based on the number of in-flight I/Os"
+	depends on DM_MULTIPATH
+	---help---
+	  This path selector is a dynamic load balancer which selects
+	  the path with the least number of in-flight I/Os.
+
+	  If unsure, say N.
+
+config DM_MULTIPATH_ST
+	tristate "I/O Path Selector based on the service time"
+	depends on DM_MULTIPATH
+	---help---
+	  This path selector is a dynamic load balancer which selects
+	  the path expected to complete the incoming I/O in the shortest
+	  time.
+
+	  If unsure, say N.
+
 config DM_DELAY
 	tristate "I/O delaying target (EXPERIMENTAL)"
 	depends on BLK_DEV_DM && EXPERIMENTAL

drivers/md/Makefile

@@ -8,6 +8,8 @@ dm-multipath-y	+= dm-path-selector.o dm-mpath.o
 dm-snapshot-y	+= dm-snap.o dm-exception-store.o dm-snap-transient.o \
 		    dm-snap-persistent.o
 dm-mirror-y	+= dm-raid1.o
+dm-log-userspace-y \
+		+= dm-log-userspace-base.o dm-log-userspace-transfer.o
 md-mod-y	+= md.o bitmap.o
 raid456-y	+= raid5.o
 raid6_pq-y	+= raid6algos.o raid6recov.o raid6tables.o \
@@ -36,8 +38,11 @@ obj-$(CONFIG_BLK_DEV_DM)	+= dm-mod.o
 obj-$(CONFIG_DM_CRYPT)		+= dm-crypt.o
 obj-$(CONFIG_DM_DELAY)		+= dm-delay.o
 obj-$(CONFIG_DM_MULTIPATH)	+= dm-multipath.o dm-round-robin.o
+obj-$(CONFIG_DM_MULTIPATH_QL)	+= dm-queue-length.o
+obj-$(CONFIG_DM_MULTIPATH_ST)	+= dm-service-time.o
 obj-$(CONFIG_DM_SNAPSHOT)	+= dm-snapshot.o
 obj-$(CONFIG_DM_MIRROR)		+= dm-mirror.o dm-log.o dm-region-hash.o
+obj-$(CONFIG_DM_LOG_USERSPACE)	+= dm-log-userspace.o
 obj-$(CONFIG_DM_ZERO)		+= dm-zero.o
 
 quiet_cmd_unroll = UNROLL  $@

drivers/md/dm-crypt.c

@@ -1132,6 +1132,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad_crypt_queue;
 	}
 
+	ti->num_flush_requests = 1;
 	ti->private = cc;
 	return 0;
 
@@ -1189,6 +1190,13 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
 		     union map_info *map_context)
 {
 	struct dm_crypt_io *io;
+	struct crypt_config *cc;
+
+	if (unlikely(bio_empty_barrier(bio))) {
+		cc = ti->private;
+		bio->bi_bdev = cc->dev->bdev;
+		return DM_MAPIO_REMAPPED;
+	}
 
 	io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin);
 
@@ -1305,9 +1313,17 @@ static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
 	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
 }
 
+static int crypt_iterate_devices(struct dm_target *ti,
+				 iterate_devices_callout_fn fn, void *data)
+{
+	struct crypt_config *cc = ti->private;
+
+	return fn(ti, cc->dev, cc->start, data);
+}
+
 static struct target_type crypt_target = {
 	.name   = "crypt",
-	.version= {1, 6, 0},
+	.version = {1, 7, 0},
 	.module = THIS_MODULE,
 	.ctr    = crypt_ctr,
 	.dtr    = crypt_dtr,
@@ -1318,6 +1334,7 @@ static struct target_type crypt_target = {
 	.resume = crypt_resume,
 	.message = crypt_message,
 	.merge  = crypt_merge,
+	.iterate_devices = crypt_iterate_devices,
 };
 
 static int __init dm_crypt_init(void)

drivers/md/dm-delay.c

@@ -197,6 +197,7 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	mutex_init(&dc->timer_lock);
 	atomic_set(&dc->may_delay, 1);
 
+	ti->num_flush_requests = 1;
 	ti->private = dc;
 	return 0;
 
@@ -278,6 +279,7 @@ static int delay_map(struct dm_target *ti, struct bio *bio,
 
 	if ((bio_data_dir(bio) == WRITE) && (dc->dev_write)) {
 		bio->bi_bdev = dc->dev_write->bdev;
+		if (bio_sectors(bio))
 			bio->bi_sector = dc->start_write +
 					 (bio->bi_sector - ti->begin);
 
@@ -316,9 +318,26 @@ static int delay_status(struct dm_target *ti, status_type_t type,
 	return 0;
 }
 
+static int delay_iterate_devices(struct dm_target *ti,
+				 iterate_devices_callout_fn fn, void *data)
+{
+	struct delay_c *dc = ti->private;
+	int ret = 0;
+
+	ret = fn(ti, dc->dev_read, dc->start_read, data);
+	if (ret)
+		goto out;
+
+	if (dc->dev_write)
+		ret = fn(ti, dc->dev_write, dc->start_write, data);
+
+out:
+	return ret;
+}
+
 static struct target_type delay_target = {
 	.name	     = "delay",
-	.version     = {1, 0, 2},
+	.version     = {1, 1, 0},
 	.module      = THIS_MODULE,
 	.ctr	     = delay_ctr,
 	.dtr	     = delay_dtr,
@@ -326,6 +345,7 @@ static struct target_type delay_target = {
 	.presuspend  = delay_presuspend,
 	.resume	     = delay_resume,
 	.status	     = delay_status,
+	.iterate_devices = delay_iterate_devices,
 };
 
 static int __init dm_delay_init(void)

drivers/md/dm-exception-store.c

@@ -216,7 +216,7 @@ int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
 		return -EINVAL;
 	}
 
-	type = get_type(argv[1]);
+	type = get_type(&persistent);
 	if (!type) {
 		ti->error = "Exception store type not recognised";
 		r = -EINVAL;

drivers/md/dm-exception-store.h

@@ -156,7 +156,7 @@ static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
  */
 static inline sector_t get_dev_size(struct block_device *bdev)
 {
-	return bdev->bd_inode->i_size >> SECTOR_SHIFT;
+	return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
 }
 
 static inline chunk_t sector_to_chunk(struct dm_exception_store *store,

drivers/md/dm-io.c

@@ -22,6 +22,7 @@ struct dm_io_client {
 /* FIXME: can we shrink this ? */
 struct io {
 	unsigned long error_bits;
+	unsigned long eopnotsupp_bits;
 	atomic_t count;
 	struct task_struct *sleeper;
 	struct dm_io_client *client;
@@ -107,8 +108,11 @@ static inline unsigned bio_get_region(struct bio *bio)
  *---------------------------------------------------------------*/
 static void dec_count(struct io *io, unsigned int region, int error)
 {
-	if (error)
+	if (error) {
 		set_bit(region, &io->error_bits);
+		if (error == -EOPNOTSUPP)
+			set_bit(region, &io->eopnotsupp_bits);
+	}
 
 	if (atomic_dec_and_test(&io->count)) {
 		if (io->sleeper)
@@ -360,7 +364,9 @@ static int sync_io(struct dm_io_client *client, unsigned int num_regions,
 		return -EIO;
 	}
 
+retry:
 	io.error_bits = 0;
+	io.eopnotsupp_bits = 0;
 	atomic_set(&io.count, 1); /* see dispatch_io() */
 	io.sleeper = current;
 	io.client = client;
@@ -377,6 +383,11 @@ static int sync_io(struct dm_io_client *client, unsigned int num_regions,
 	}
 	set_current_state(TASK_RUNNING);
 
+	if (io.eopnotsupp_bits && (rw & (1 << BIO_RW_BARRIER))) {
+		rw &= ~(1 << BIO_RW_BARRIER);
+		goto retry;
+	}
+
 	if (error_bits)
 		*error_bits = io.error_bits;
 
@@ -397,6 +408,7 @@ static int async_io(struct dm_io_client *client, unsigned int num_regions,
 
 	io = mempool_alloc(client->pool, GFP_NOIO);
 	io->error_bits = 0;
+	io->eopnotsupp_bits = 0;
 	atomic_set(&io->count, 1); /* see dispatch_io() */
 	io->sleeper = NULL;
 	io->client = client;

drivers/md/dm-ioctl.c

@@ -276,7 +276,7 @@ static void dm_hash_remove_all(int keep_open_devices)
 	up_write(&_hash_lock);
 }
 
-static int dm_hash_rename(const char *old, const char *new)
+static int dm_hash_rename(uint32_t cookie, const char *old, const char *new)
 {
 	char *new_name, *old_name;
 	struct hash_cell *hc;
@@ -333,7 +333,7 @@ static int dm_hash_rename(const char *old, const char *new)
 		dm_table_put(table);
 	}
 
-	dm_kobject_uevent(hc->md);
+	dm_kobject_uevent(hc->md, KOBJ_CHANGE, cookie);
 
 	dm_put(hc->md);
 	up_write(&_hash_lock);
@@ -680,6 +680,9 @@ static int dev_remove(struct dm_ioctl *param, size_t param_size)
 
 	__hash_remove(hc);
 	up_write(&_hash_lock);
+
+	dm_kobject_uevent(md, KOBJ_REMOVE, param->event_nr);
+
 	dm_put(md);
 	param->data_size = 0;
 	return 0;
@@ -715,7 +718,7 @@ static int dev_rename(struct dm_ioctl *param, size_t param_size)
 		return r;
 
 	param->data_size = 0;
-	return dm_hash_rename(param->name, new_name);
+	return dm_hash_rename(param->event_nr, param->name, new_name);
 }
 
 static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
@@ -842,8 +845,11 @@ static int do_resume(struct dm_ioctl *param)
 	if (dm_suspended(md))
 		r = dm_resume(md);
 
-	if (!r)
+
+	if (!r) {
+		dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr);
 		r = __dev_status(md, param);
+	}
 
 	dm_put(md);
 	return r;
@@ -1044,6 +1050,12 @@ static int populate_table(struct dm_table *table,
 		next = spec->next;
 	}
 
+	r = dm_table_set_type(table);
+	if (r) {
+		DMWARN("unable to set table type");
+		return r;
+	}
+
 	return dm_table_complete(table);
 }
 
@@ -1089,6 +1101,13 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
 		goto out;
 	}
 
+	r = dm_table_alloc_md_mempools(t);
+	if (r) {
+		DMWARN("unable to allocate mempools for this table");
+		dm_table_destroy(t);
+		goto out;
+	}
+
 	down_write(&_hash_lock);
 	hc = dm_get_mdptr(md);
 	if (!hc || hc->md != md) {

drivers/md/dm-linear.c

@@ -53,6 +53,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad;
 	}
 
+	ti->num_flush_requests = 1;
 	ti->private = lc;
 	return 0;
 
@@ -81,6 +82,7 @@ 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))
 		bio->bi_sector = linear_map_sector(ti, bio->bi_sector);
 }
 
@@ -132,9 +134,17 @@ static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
 	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
 }
 
+static int linear_iterate_devices(struct dm_target *ti,
+				  iterate_devices_callout_fn fn, void *data)
+{
+	struct linear_c *lc = ti->private;
+
+	return fn(ti, lc->dev, lc->start, data);
+}
+
 static struct target_type linear_target = {
 	.name   = "linear",
-	.version= {1, 0, 3},
+	.version = {1, 1, 0},
 	.module = THIS_MODULE,
 	.ctr    = linear_ctr,
 	.dtr    = linear_dtr,
@@ -142,6 +152,7 @@ static struct target_type linear_target = {
 	.status = linear_status,
 	.ioctl  = linear_ioctl,
 	.merge  = linear_merge,
+	.iterate_devices = linear_iterate_devices,
 };
 
 int __init dm_linear_init(void)

drivers/md/dm-log-userspace-transfer.c

+/*
+ * Copyright (C) 2006-2009 Red Hat, Inc.
+ *
+ * This file is released under the LGPL.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <net/sock.h>
+#include <linux/workqueue.h>
+#include <linux/connector.h>
+#include <linux/device-mapper.h>
+#include <linux/dm-log-userspace.h>
+
+#include "dm-log-userspace-transfer.h"
+
+static uint32_t dm_ulog_seq;
+
+/*
+ * Netlink/Connector is an unreliable protocol.  How long should
+ * we wait for a response before assuming it was lost and retrying?
+ * (If we do receive a response after this time, it will be discarded
+ * and the response to the resent request will be waited for.
+ */
+#define DM_ULOG_RETRY_TIMEOUT (15 * HZ)
+
+/*
+ * Pre-allocated space for speed
+ */
+#define DM_ULOG_PREALLOCED_SIZE 512
+static struct cn_msg *prealloced_cn_msg;
+static struct dm_ulog_request *prealloced_ulog_tfr;
+
+static struct cb_id ulog_cn_id = {
+	.idx = CN_IDX_DM,
+	.val = CN_VAL_DM_USERSPACE_LOG
+};
+
+static DEFINE_MUTEX(dm_ulog_lock);
+
+struct receiving_pkg {
+	struct list_head list;
+	struct completion complete;
+
+	uint32_t seq;
+
+	int error;
+	size_t *data_size;
+	char *data;
+};
+
+static DEFINE_SPINLOCK(receiving_list_lock);
+static struct list_head receiving_list;
+
+static int dm_ulog_sendto_server(struct dm_ulog_request *tfr)
+{
+	int r;
+	struct cn_msg *msg = prealloced_cn_msg;
+
+	memset(msg, 0, sizeof(struct cn_msg));
+
+	msg->id.idx = ulog_cn_id.idx;
+	msg->id.val = ulog_cn_id.val;
+	msg->ack = 0;
+	msg->seq = tfr->seq;
+	msg->len = sizeof(struct dm_ulog_request) + tfr->data_size;
+
+	r = cn_netlink_send(msg, 0, gfp_any());
+
+	return r;
+}
+
+/*
+ * Parameters for this function can be either msg or tfr, but not
+ * both.  This function fills in the reply for a waiting request.
+ * If just msg is given, then the reply is simply an ACK from userspace
+ * that the request was received.
+ *
+ * Returns: 0 on success, -ENOENT on failure
+ */
+static int fill_pkg(struct cn_msg *msg, struct dm_ulog_request *tfr)
+{
+	uint32_t rtn_seq = (msg) ? msg->seq : (tfr) ? tfr->seq : 0;
+	struct receiving_pkg *pkg;
+
+	/*
+	 * The 'receiving_pkg' entries in this list are statically
+	 * allocated on the stack in 'dm_consult_userspace'.
+	 * Each process that is waiting for a reply from the user
+	 * space server will have an entry in this list.
+	 *
+	 * We are safe to do it this way because the stack space
+	 * is unique to each process, but still addressable by
+	 * other processes.
+	 */
+	list_for_each_entry(pkg, &receiving_list, list) {
+		if (rtn_seq != pkg->seq)
+			continue;
+
+		if (msg) {
+			pkg->error = -msg->ack;
+			/*
+			 * If we are trying again, we will need to know our
+			 * storage capacity.  Otherwise, along with the
+			 * error code, we make explicit that we have no data.
+			 */
+			if (pkg->error != -EAGAIN)
+				*(pkg->data_size) = 0;
+		} else if (tfr->data_size > *(pkg->data_size)) {
+			DMERR("Insufficient space to receive package [%u] "
+			      "(%u vs %lu)", tfr->request_type,
+			      tfr->data_size, *(pkg->data_size));
+
+			*(pkg->data_size) = 0;
+			pkg->error = -ENOSPC;
+		} else {
+			pkg->error = tfr->error;
+			memcpy(pkg->data, tfr->data, tfr->data_size);
+			*(pkg->data_size) = tfr->data_size;
+		}
+		complete(&pkg->complete);
+		return 0;
+	}
+
+	return -ENOENT;
+}
+
+/*
+ * This is the connector callback that delivers data
+ * that was sent from userspace.
+ */
+static void cn_ulog_callback(void *data)
+{
+	struct cn_msg *msg = (struct cn_msg *)data;
+	struct dm_ulog_request *tfr = (struct dm_ulog_request *)(msg + 1);
+
+	spin_lock(&receiving_list_lock);
+	if (msg->len == 0)
+		fill_pkg(msg, NULL);
+	else if (msg->len < sizeof(*tfr))
+		DMERR("Incomplete message received (expected %u, got %u): [%u]",
+		      (unsigned)sizeof(*tfr), msg->len, msg->seq);
+	else
+		fill_pkg(NULL, tfr);
+	spin_unlock(&receiving_list_lock);
+}
+
+/**
+ * dm_consult_userspace
+ * @uuid: log's uuid (must be DM_UUID_LEN in size)
+ * @request_type:  found in include/linux/dm-log-userspace.h
+ * @data: data to tx to the server
+ * @data_size: size of data in bytes
+ * @rdata: place to put return data from server
+ * @rdata_size: value-result (amount of space given/amount of space used)
+ *
+ * rdata_size is undefined on failure.
+ *
+ * Memory used to communicate with userspace is zero'ed
+ * before populating to ensure that no unwanted bits leak
+ * from kernel space to user-space.  All userspace log communications
+ * between kernel and user space go through this function.
+ *
+ * Returns: 0 on success, -EXXX on failure
+ **/
+int dm_consult_userspace(const char *uuid, int request_type,
+			 char *data, size_t data_size,
+			 char *rdata, size_t *rdata_size)
+{
+	int r = 0;
+	size_t dummy = 0;
+	int overhead_size =
+		sizeof(struct dm_ulog_request *) + sizeof(struct cn_msg);
+	struct dm_ulog_request *tfr = prealloced_ulog_tfr;
+	struct receiving_pkg pkg;
+
+	if (data_size > (DM_ULOG_PREALLOCED_SIZE - overhead_size)) {
+		DMINFO("Size of tfr exceeds preallocated size");
+		return -EINVAL;
+	}
+
+	if (!rdata_size)
+		rdata_size = &dummy;
+resend:
+	/*
+	 * We serialize the sending of requests so we can
+	 * use the preallocated space.
+	 */
+	mutex_lock(&dm_ulog_lock);
+
+	memset(tfr, 0, DM_ULOG_PREALLOCED_SIZE - overhead_size);
+	memcpy(tfr->uuid, uuid, DM_UUID_LEN);
+	tfr->seq = dm_ulog_seq++;
+
+	/*
+	 * Must be valid request type (all other bits set to
+	 * zero).  This reserves other bits for possible future
+	 * use.
+	 */
+	tfr->request_type = request_type & DM_ULOG_REQUEST_MASK;
+
+	tfr->data_size = data_size;
+	if (data && data_size)
+		memcpy(tfr->data, data, data_size);
+
+	memset(&pkg, 0, sizeof(pkg));
+	init_completion(&pkg.complete);
+	pkg.seq = tfr->seq;
+	pkg.data_size = rdata_size;
+	pkg.data = rdata;
+	spin_lock(&receiving_list_lock);
+	list_add(&(pkg.list), &receiving_list);
+	spin_unlock(&receiving_list_lock);
+
+	r = dm_ulog_sendto_server(tfr);
+
+	mutex_unlock(&dm_ulog_lock);
+
+	if (r) {
+		DMERR("Unable to send log request [%u] to userspace: %d",
+		      request_type, r);
+		spin_lock(&receiving_list_lock);
+		list_del_init(&(pkg.list));
+		spin_unlock(&receiving_list_lock);
+
+		goto out;
+	}
+
+	r = wait_for_completion_timeout(&(pkg.complete), DM_ULOG_RETRY_TIMEOUT);
+	spin_lock(&receiving_list_lock);
+	list_del_init(&(pkg.list));
+	spin_unlock(&receiving_list_lock);
+	if (!r) {
+		DMWARN("[%s] Request timed out: [%u/%u] - retrying",
+		       (strlen(uuid) > 8) ?
+		       (uuid + (strlen(uuid) - 8)) : (uuid),
+		       request_type, pkg.seq);
+		goto resend;
+	}
+
+	r = pkg.error;
+	if (r == -EAGAIN)
+		goto resend;
+
+out:
+	return r;
+}
+
+int dm_ulog_tfr_init(void)
+{
+	int r;
+	void *prealloced;
+
+	INIT_LIST_HEAD(&receiving_list);
+
+	prealloced = kmalloc(DM_ULOG_PREALLOCED_SIZE, GFP_KERNEL);
+	if (!prealloced)
+		return -ENOMEM;
+
+	prealloced_cn_msg = prealloced;
+	prealloced_ulog_tfr = prealloced + sizeof(struct cn_msg);
+
+	r = cn_add_callback(&ulog_cn_id, "dmlogusr", cn_ulog_callback);
+	if (r) {
+		cn_del_callback(&ulog_cn_id);
+		return r;
+	}
+
+	return 0;
+}
+
+void dm_ulog_tfr_exit(void)
+{
+	cn_del_callback(&ulog_cn_id);
+	kfree(prealloced_cn_msg);
+}

drivers/md/dm-log-userspace-transfer.h

+/*
+ * Copyright (C) 2006-2009 Red Hat, Inc.
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef __DM_LOG_USERSPACE_TRANSFER_H__
+#define __DM_LOG_USERSPACE_TRANSFER_H__
+
+#define DM_MSG_PREFIX "dm-log-userspace"
+
+int dm_ulog_tfr_init(void);
+void dm_ulog_tfr_exit(void);
+int dm_consult_userspace(const char *uuid, int request_type,
+			 char *data, size_t data_size,
+			 char *rdata, size_t *rdata_size);
+
+#endif /* __DM_LOG_USERSPACE_TRANSFER_H__ */

drivers/md/dm-log.c

@@ -412,11 +412,12 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
 		/*
 		 * Buffer holds both header and bitset.
 		 */
-		buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) +
-				       bitset_size,
-				       ti->limits.logical_block_size);
+		buf_size =
+		    dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
+				bdev_logical_block_size(lc->header_location.
+							    bdev));
 
-		if (buf_size > dev->bdev->bd_inode->i_size) {
+		if (buf_size > i_size_read(dev->bdev->bd_inode)) {
 			DMWARN("log device %s too small: need %llu bytes",
 				dev->name, (unsigned long long)buf_size);
 			kfree(lc);

drivers/md/dm-path-selector.h

@@ -56,7 +56,8 @@ struct path_selector_type {
 	 * the path fails.
 	 */
 	struct dm_path *(*select_path) (struct path_selector *ps,
-				     unsigned *repeat_count);
+					unsigned *repeat_count,
+					size_t nr_bytes);
 
 	/*
 	 * Notify the selector that a path has failed.
@@ -75,7 +76,10 @@ struct path_selector_type {
 	int (*status) (struct path_selector *ps, struct dm_path *path,
 		       status_type_t type, char *result, unsigned int maxlen);
 
-	int (*end_io) (struct path_selector *ps, struct dm_path *path);
+	int (*start_io) (struct path_selector *ps, struct dm_path *path,
+			 size_t nr_bytes);
+	int (*end_io) (struct path_selector *ps, struct dm_path *path,
+		       size_t nr_bytes);
 };
 
 /* Register a path selector */

drivers/md/dm-queue-length.c

+/*
+ * Copyright (C) 2004-2005 IBM Corp.  All Rights Reserved.
+ * Copyright (C) 2006-2009 NEC Corporation.
+ *
+ * dm-queue-length.c
+ *
+ * Module Author: Stefan Bader, IBM
+ * Modified by: Kiyoshi Ueda, NEC
+ *
+ * This file is released under the GPL.
+ *
+ * queue-length path selector - choose a path with the least number of
+ * in-flight I/Os.
+ */
+
+#include "dm.h"
+#include "dm-path-selector.h"
+
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <asm/atomic.h>
+
+#define DM_MSG_PREFIX	"multipath queue-length"
+#define QL_MIN_IO	128
+#define QL_VERSION	"0.1.0"
+
+struct selector {
+	struct list_head	valid_paths;
+	struct list_head	failed_paths;
+};
+
+struct path_info {
+	struct list_head	list;
+	struct dm_path		*path;
+	unsigned		repeat_count;
+	atomic_t		qlen;	/* the number of in-flight I/Os */
+};
+
+static struct selector *alloc_selector(void)
+{
+	struct selector *s = kmalloc(sizeof(*s), GFP_KERNEL);
+
+	if (s) {
+		INIT_LIST_HEAD(&s->valid_paths);
+		INIT_LIST_HEAD(&s->failed_paths);
+	}
+
+	return s;
+}
+
+static int ql_create(struct path_selector *ps, unsigned argc, char **argv)
+{
+	struct selector *s = alloc_selector();
+
+	if (!s)
+		return -ENOMEM;
+
+	ps->context = s;
+	return 0;
+}
+
+static void ql_free_paths(struct list_head *paths)
+{
+	struct path_info *pi, *next;
+
+	list_for_each_entry_safe(pi, next, paths, list) {
+		list_del(&pi->list);
+		kfree(pi);
+	}
+}
+
+static void ql_destroy(struct path_selector *ps)
+{
+	struct selector *s = ps->context;
+
+	ql_free_paths(&s->valid_paths);
+	ql_free_paths(&s->failed_paths);
+	kfree(s);
+	ps->context = NULL;
+}
+
+static int ql_status(struct path_selector *ps, struct dm_path *path,
+		     status_type_t type, char *result, unsigned maxlen)
+{
+	unsigned sz = 0;
+	struct path_info *pi;
+
+	/* When called with NULL path, return selector status/args. */
+	if (!path)
+		DMEMIT("0 ");
+	else {
+		pi = path->pscontext;
+
+		switch (type) {
+		case STATUSTYPE_INFO:
+			DMEMIT("%d ", atomic_read(&pi->qlen));
+			break;
+		case STATUSTYPE_TABLE:
+			DMEMIT("%u ", pi->repeat_count);
+			break;
+		}
+	}
+
+	return sz;
+}
+
+static int ql_add_path(struct path_selector *ps, struct dm_path *path,
+		       int argc, char **argv, char **error)
+{
+	struct selector *s = ps->context;
+	struct path_info *pi;
+	unsigned repeat_count = QL_MIN_IO;
+
+	/*
+	 * Arguments: [<repeat_count>]
+	 * 	<repeat_count>: The number of I/Os before switching path.
+	 * 			If not given, default (QL_MIN_IO) is used.
+	 */
+	if (argc > 1) {
+		*error = "queue-length ps: incorrect number of arguments";
+		return -EINVAL;
+	}
+
+	if ((argc == 1) && (sscanf(argv[0], "%u", &repeat_count) != 1)) {
+		*error = "queue-length ps: invalid repeat count";
+		return -EINVAL;
+	}
+
+	/* Allocate the path information structure */
+	pi = kmalloc(sizeof(*pi), GFP_KERNEL);
+	if (!pi) {
+		*error = "queue-length ps: Error allocating path information";
+		return -ENOMEM;
+	}
+
+	pi->path = path;
+	pi->repeat_count = repeat_count;
+	atomic_set(&pi->qlen, 0);
+
+	path->pscontext = pi;
+
+	list_add_tail(&pi->list, &s->valid_paths);
+
+	return 0;
+}
+
+static void ql_fail_path(struct path_selector *ps, struct dm_path *path)
+{
+	struct selector *s = ps->context;
+	struct path_info *pi = path->pscontext;
+
+	list_move(&pi->list, &s->failed_paths);
+}
+
+static int ql_reinstate_path(struct path_selector *ps, struct dm_path *path)
+{
+	struct selector *s = ps->context;
+	struct path_info *pi = path->pscontext;
+
+	list_move_tail(&pi->list, &s->valid_paths);
+
+	return 0;
+}
+
+/*
+ * Select a path having the minimum number of in-flight I/Os
+ */
+static struct dm_path *ql_select_path(struct path_selector *ps,
+				      unsigned *repeat_count, size_t nr_bytes)
+{
+	struct selector *s = ps->context;
+	struct path_info *pi = NULL, *best = NULL;
+
+	if (list_empty(&s->valid_paths))
+		return NULL;
+
+	/* Change preferred (first in list) path to evenly balance. */
+	list_move_tail(s->valid_paths.next, &s->valid_paths);
+
+	list_for_each_entry(pi, &s->valid_paths, list) {
+		if (!best ||
+		    (atomic_read(&pi->qlen) < atomic_read(&best->qlen)))
+			best = pi;
+
+		if (!atomic_read(&best->qlen))
+			break;
+	}
+
+	if (!best)
+		return NULL;
+
+	*repeat_count = best->repeat_count;
+
+	return best->path;
+}
+
+static int ql_start_io(struct path_selector *ps, struct dm_path *path,
+		       size_t nr_bytes)
+{
+	struct path_info *pi = path->pscontext;
+
+	atomic_inc(&pi->qlen);
+
+	return 0;
+}
+
+static int ql_end_io(struct path_selector *ps, struct dm_path *path,
+		     size_t nr_bytes)
+{
+	struct path_info *pi = path->pscontext;
+
+	atomic_dec(&pi->qlen);
+
+	return 0;
+}
+
+static struct path_selector_type ql_ps = {
+	.name		= "queue-length",
+	.module		= THIS_MODULE,
+	.table_args	= 1,
+	.info_args	= 1,
+	.create		= ql_create,
+	.destroy	= ql_destroy,
+	.status		= ql_status,
+	.add_path	= ql_add_path,
+	.fail_path	= ql_fail_path,
+	.reinstate_path	= ql_reinstate_path,
+	.select_path	= ql_select_path,
+	.start_io	= ql_start_io,
+	.end_io		= ql_end_io,
+};
+
+static int __init dm_ql_init(void)
+{
+	int r = dm_register_path_selector(&ql_ps);
+
+	if (r < 0)
+		DMERR("register failed %d", r);
+
+	DMINFO("version " QL_VERSION " loaded");
+
+	return r;
+}
+
+static void __exit dm_ql_exit(void)
+{
+	int r = dm_unregister_path_selector(&ql_ps);
+
+	if (r < 0)
+		DMERR("unregister failed %d", r);
+}
+
+module_init(dm_ql_init);
+module_exit(dm_ql_exit);
+
+MODULE_AUTHOR("Stefan Bader <Stefan.Bader at de.ibm.com>");
+MODULE_DESCRIPTION(
+	"(C) Copyright IBM Corp. 2004,2005   All Rights Reserved.\n"
+	DM_NAME " path selector to balance the number of in-flight I/Os"
+);
+MODULE_LICENSE("GPL");

drivers/md/dm-raid1.c

@@ -1283,9 +1283,23 @@ static int mirror_status(struct dm_target *ti, status_type_t type,
 	return 0;
 }
 
+static int mirror_iterate_devices(struct dm_target *ti,
+				  iterate_devices_callout_fn fn, void *data)
+{
+	struct mirror_set *ms = ti->private;
+	int ret = 0;
+	unsigned i;
+
+	for (i = 0; !ret && i < ms->nr_mirrors; i++)
+		ret = fn(ti, ms->mirror[i].dev,
+			 ms->mirror[i].offset, data);
+
+	return ret;
+}
+
 static struct target_type mirror_target = {
 	.name	 = "mirror",
-	.version = {1, 0, 20},
+	.version = {1, 12, 0},
 	.module	 = THIS_MODULE,
 	.ctr	 = mirror_ctr,
 	.dtr	 = mirror_dtr,
@@ -1295,6 +1309,7 @@ static struct target_type mirror_target = {
 	.postsuspend = mirror_postsuspend,
 	.resume	 = mirror_resume,
 	.status	 = mirror_status,
+	.iterate_devices = mirror_iterate_devices,
 };
 
 static int __init dm_mirror_init(void)

drivers/md/dm-region-hash.c

@@ -283,7 +283,7 @@ static struct dm_region *__rh_alloc(struct dm_region_hash *rh, region_t region)
 
 	nreg = mempool_alloc(rh->region_pool, GFP_ATOMIC);
 	if (unlikely(!nreg))
-		nreg = kmalloc(sizeof(*nreg), GFP_NOIO);
+		nreg = kmalloc(sizeof(*nreg), GFP_NOIO | __GFP_NOFAIL);
 
 	nreg->state = rh->log->type->in_sync(rh->log, region, 1) ?
 		      DM_RH_CLEAN : DM_RH_NOSYNC;

drivers/md/dm-round-robin.c

@@ -161,7 +161,7 @@ static int rr_reinstate_path(struct path_selector *ps, struct dm_path *p)
 }
 
 static struct dm_path *rr_select_path(struct path_selector *ps,
-				   unsigned *repeat_count)
+				      unsigned *repeat_count, size_t nr_bytes)
 {
 	struct selector *s = (struct selector *) ps->context;
 	struct path_info *pi = NULL;

drivers/md/dm-service-time.c

+/*
+ * Copyright (C) 2007-2009 NEC Corporation.  All Rights Reserved.
+ *
+ * Module Author: Kiyoshi Ueda
+ *
+ * This file is released under the GPL.
+ *
+ * Throughput oriented path selector.
+ */
+
+#include "dm.h"
+#include "dm-path-selector.h"
+
+#define DM_MSG_PREFIX	"multipath service-time"
+#define ST_MIN_IO	1
+#define ST_MAX_RELATIVE_THROUGHPUT	100
+#define ST_MAX_RELATIVE_THROUGHPUT_SHIFT	7
+#define ST_MAX_INFLIGHT_SIZE	((size_t)-1 >> ST_MAX_RELATIVE_THROUGHPUT_SHIFT)
+#define ST_VERSION	"0.2.0"
+
+struct selector {
+	struct list_head valid_paths;
+	struct list_head failed_paths;
+};
+
+struct path_info {
+	struct list_head list;
+	struct dm_path *path;
+	unsigned repeat_count;
+	unsigned relative_throughput;
+	atomic_t in_flight_size;	/* Total size of in-flight I/Os */
+};
+
+static struct selector *alloc_selector(void)
+{
+	struct selector *s = kmalloc(sizeof(*s), GFP_KERNEL);
+
+	if (s) {
+		INIT_LIST_HEAD(&s->valid_paths);
+		INIT_LIST_HEAD(&s->failed_paths);
+	}
+
+	return s;
+}
+
+static int st_create(struct path_selector *ps, unsigned argc, char **argv)
+{
+	struct selector *s = alloc_selector();
+
+	if (!s)
+		return -ENOMEM;
+
+	ps->context = s;
+	return 0;
+}
+
+static void free_paths(struct list_head *paths)
+{
+	struct path_info *pi, *next;
+
+	list_for_each_entry_safe(pi, next, paths, list) {
+		list_del(&pi->list);
+		kfree(pi);
+	}
+}
+
+static void st_destroy(struct path_selector *ps)
+{
+	struct selector *s = ps->context;
+
+	free_paths(&s->valid_paths);
+	free_paths(&s->failed_paths);
+	kfree(s);
+	ps->context = NULL;
+}
+
+static int st_status(struct path_selector *ps, struct dm_path *path,
+		     status_type_t type, char *result, unsigned maxlen)
+{
+	unsigned sz = 0;
+	struct path_info *pi;
+
+	if (!path)
+		DMEMIT("0 ");
+	else {
+		pi = path->pscontext;
+
+		switch (type) {
+		case STATUSTYPE_INFO:
+			DMEMIT("%d %u ", atomic_read(&pi->in_flight_size),
+			       pi->relative_throughput);
+			break;
+		case STATUSTYPE_TABLE:
+			DMEMIT("%u %u ", pi->repeat_count,
+			       pi->relative_throughput);
+			break;
+		}
+	}
+
+	return sz;
+}
+
+static int st_add_path(struct path_selector *ps, struct dm_path *path,
+		       int argc, char **argv, char **error)
+{
+	struct selector *s = ps->context;
+	struct path_info *pi;
+	unsigned repeat_count = ST_MIN_IO;
+	unsigned relative_throughput = 1;
+
+	/*
+	 * Arguments: [<repeat_count> [<relative_throughput>]]
+	 * 	<repeat_count>: The number of I/Os before switching path.
+	 * 			If not given, default (ST_MIN_IO) is used.
+	 * 	<relative_throughput>: The relative throughput value of
+	 *			the path among all paths in the path-group.
+	 * 			The valid range: 0-<ST_MAX_RELATIVE_THROUGHPUT>
+	 *			If not given, minimum value '1' is used.
+	 *			If '0' is given, the path isn't selected while
+	 * 			other paths having a positive value are
+	 * 			available.
+	 */
+	if (argc > 2) {
+		*error = "service-time ps: incorrect number of arguments";
+		return -EINVAL;
+	}
+
+	if (argc && (sscanf(argv[0], "%u", &repeat_count) != 1)) {
+		*error = "service-time ps: invalid repeat count";
+		return -EINVAL;
+	}
+
+	if ((argc == 2) &&
+	    (sscanf(argv[1], "%u", &relative_throughput) != 1 ||
+	     relative_throughput > ST_MAX_RELATIVE_THROUGHPUT)) {
+		*error = "service-time ps: invalid relative_throughput value";
+		return -EINVAL;
+	}
+
+	/* allocate the path */
+	pi = kmalloc(sizeof(*pi), GFP_KERNEL);
+	if (!pi) {
+		*error = "service-time ps: Error allocating path context";
+		return -ENOMEM;
+	}
+
+	pi->path = path;
+	pi->repeat_count = repeat_count;
+	pi->relative_throughput = relative_throughput;
+	atomic_set(&pi->in_flight_size, 0);
+
+	path->pscontext = pi;
+
+	list_add_tail(&pi->list, &s->valid_paths);
+
+	return 0;
+}
+
+static void st_fail_path(struct path_selector *ps, struct dm_path *path)
+{
+	struct selector *s = ps->context;
+	struct path_info *pi = path->pscontext;
+
+	list_move(&pi->list, &s->failed_paths);
+}
+
+static int st_reinstate_path(struct path_selector *ps, struct dm_path *path)
+{
+	struct selector *s = ps->context;
+	struct path_info *pi = path->pscontext;
+
+	list_move_tail(&pi->list, &s->valid_paths);
+
+	return 0;
+}
+
+/*
+ * Compare the estimated service time of 2 paths, pi1 and pi2,
+ * for the incoming I/O.
+ *
+ * Returns:
+ * < 0 : pi1 is better
+ * 0   : no difference between pi1 and pi2
+ * > 0 : pi2 is better
+ *
+ * Description:
+ * Basically, the service time is estimated by:
+ *     ('pi->in-flight-size' + 'incoming') / 'pi->relative_throughput'
+ * To reduce the calculation, some optimizations are made.
+ * (See comments inline)
+ */
+static int st_compare_load(struct path_info *pi1, struct path_info *pi2,
+			   size_t incoming)
+{
+	size_t sz1, sz2, st1, st2;
+
+	sz1 = atomic_read(&pi1->in_flight_size);
+	sz2 = atomic_read(&pi2->in_flight_size);
+
+	/*
+	 * Case 1: Both have same throughput value. Choose less loaded path.
+	 */
+	if (pi1->relative_throughput == pi2->relative_throughput)
+		return sz1 - sz2;
+
+	/*
+	 * Case 2a: Both have same load. Choose higher throughput path.
+	 * Case 2b: One path has no throughput value. Choose the other one.
+	 */
+	if (sz1 == sz2 ||
+	    !pi1->relative_throughput || !pi2->relative_throughput)
+		return pi2->relative_throughput - pi1->relative_throughput;
+
+	/*
+	 * Case 3: Calculate service time. Choose faster path.
+	 *         Service time using pi1:
+	 *             st1 = (sz1 + incoming) / pi1->relative_throughput
+	 *         Service time using pi2:
+	 *             st2 = (sz2 + incoming) / pi2->relative_throughput
+	 *
+	 *         To avoid the division, transform the expression to use
+	 *         multiplication.
+	 *         Because ->relative_throughput > 0 here, if st1 < st2,
+	 *         the expressions below are the same meaning:
+	 *             (sz1 + incoming) / pi1->relative_throughput <
+	 *                 (sz2 + incoming) / pi2->relative_throughput
+	 *             (sz1 + incoming) * pi2->relative_throughput <
+	 *                 (sz2 + incoming) * pi1->relative_throughput
+	 *         So use the later one.
+	 */
+	sz1 += incoming;
+	sz2 += incoming;
+	if (unlikely(sz1 >= ST_MAX_INFLIGHT_SIZE ||
+		     sz2 >= ST_MAX_INFLIGHT_SIZE)) {
+		/*
+		 * Size may be too big for multiplying pi->relative_throughput
+		 * and overflow.
+		 * To avoid the overflow and mis-selection, shift down both.
+		 */
+		sz1 >>= ST_MAX_RELATIVE_THROUGHPUT_SHIFT;
+		sz2 >>= ST_MAX_RELATIVE_THROUGHPUT_SHIFT;
+	}
+	st1 = sz1 * pi2->relative_throughput;
+	st2 = sz2 * pi1->relative_throughput;
+	if (st1 != st2)
+		return st1 - st2;
+
+	/*
+	 * Case 4: Service time is equal. Choose higher throughput path.
+	 */
+	return pi2->relative_throughput - pi1->relative_throughput;
+}
+
+static struct dm_path *st_select_path(struct path_selector *ps,
+				      unsigned *repeat_count, size_t nr_bytes)
+{
+	struct selector *s = ps->context;
+	struct path_info *pi = NULL, *best = NULL;
+
+	if (list_empty(&s->valid_paths))
+		return NULL;
+
+	/* Change preferred (first in list) path to evenly balance. */
+	list_move_tail(s->valid_paths.next, &s->valid_paths);
+
+	list_for_each_entry(pi, &s->valid_paths, list)
+		if (!best || (st_compare_load(pi, best, nr_bytes) < 0))
+			best = pi;
+
+	if (!best)
+		return NULL;
+
+	*repeat_count = best->repeat_count;
+
+	return best->path;
+}
+
+static int st_start_io(struct path_selector *ps, struct dm_path *path,
+		       size_t nr_bytes)
+{
+	struct path_info *pi = path->pscontext;
+
+	atomic_add(nr_bytes, &pi->in_flight_size);
+
+	return 0;
+}
+
+static int st_end_io(struct path_selector *ps, struct dm_path *path,
+		     size_t nr_bytes)
+{
+	struct path_info *pi = path->pscontext;
+
+	atomic_sub(nr_bytes, &pi->in_flight_size);
+
+	return 0;
+}
+
+static struct path_selector_type st_ps = {
+	.name		= "service-time",
+	.module		= THIS_MODULE,
+	.table_args	= 2,
+	.info_args	= 2,
+	.create		= st_create,
+	.destroy	= st_destroy,
+	.status		= st_status,
+	.add_path	= st_add_path,
+	.fail_path	= st_fail_path,
+	.reinstate_path	= st_reinstate_path,
+	.select_path	= st_select_path,
+	.start_io	= st_start_io,
+	.end_io		= st_end_io,
+};
+
+static int __init dm_st_init(void)
+{
+	int r = dm_register_path_selector(&st_ps);
+
+	if (r < 0)
+		DMERR("register failed %d", r);
+
+	DMINFO("version " ST_VERSION " loaded");
+
+	return r;
+}
+
+static void __exit dm_st_exit(void)
+{
+	int r = dm_unregister_path_selector(&st_ps);
+
+	if (r < 0)
+		DMERR("unregister failed %d", r);
+}
+
+module_init(dm_st_init);
+module_exit(dm_st_exit);
+
+MODULE_DESCRIPTION(DM_NAME " throughput oriented path selector");
+MODULE_AUTHOR("Kiyoshi Ueda <k-ueda@ct.jp.nec.com>");
+MODULE_LICENSE("GPL");

drivers/md/dm-snap-persistent.c

@@ -636,7 +636,7 @@ static void persistent_commit_exception(struct dm_exception_store *store,
 	/*
 	 * Commit exceptions to disk.
 	 */
-	if (ps->valid && area_io(ps, WRITE))
+	if (ps->valid && area_io(ps, WRITE_BARRIER))
 		ps->valid = 0;
 
 	/*

drivers/md/dm-snap.c

@@ -678,6 +678,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->private = s;
 	ti->split_io = s->store->chunk_size;
+	ti->num_flush_requests = 1;
 
 	return 0;
 
@@ -1030,6 +1031,11 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
 	chunk_t chunk;
 	struct dm_snap_pending_exception *pe = NULL;
 
+	if (unlikely(bio_empty_barrier(bio))) {
+		bio->bi_bdev = s->store->cow->bdev;
+		return DM_MAPIO_REMAPPED;
+	}
+
 	chunk = sector_to_chunk(s->store, bio->bi_sector);
 
 	/* Full snapshots are not usable */
@@ -1338,6 +1344,8 @@ static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 
 	ti->private = dev;
+	ti->num_flush_requests = 1;
+
 	return 0;
 }
 
@@ -1353,6 +1361,9 @@ static int origin_map(struct dm_target *ti, struct bio *bio,
 	struct dm_dev *dev = ti->private;
 	bio->bi_bdev = dev->bdev;
 
+	if (unlikely(bio_empty_barrier(bio)))
+		return DM_MAPIO_REMAPPED;
+
 	/* Only tell snapshots if this is a write */
 	return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED;
 }

drivers/md/dm-stripe.c

@@ -167,6 +167,7 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	sc->stripes = stripes;
 	sc->stripe_width = width;
 	ti->split_io = chunk_size;
+	ti->num_flush_requests = stripes;
 
 	sc->chunk_mask = ((sector_t) chunk_size) - 1;
 	for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
@@ -211,10 +212,18 @@ static int stripe_map(struct dm_target *ti, struct bio *bio,
 		      union map_info *map_context)
 {
 	struct stripe_c *sc = (struct stripe_c *) ti->private;
+	sector_t offset, chunk;
+	uint32_t stripe;
 
-	sector_t offset = bio->bi_sector - ti->begin;
-	sector_t chunk = offset >> sc->chunk_shift;
-	uint32_t stripe = sector_div(chunk, sc->stripes);
+	if (unlikely(bio_empty_barrier(bio))) {
+		BUG_ON(map_context->flush_request >= sc->stripes);
+		bio->bi_bdev = sc->stripe[map_context->flush_request].dev->bdev;
+		return DM_MAPIO_REMAPPED;
+	}
+
+	offset = bio->bi_sector - ti->begin;
+	chunk = offset >> sc->chunk_shift;
+	stripe = sector_div(chunk, sc->stripes);
 
 	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
 	bio->bi_sector = sc->stripe[stripe].physical_start +
@@ -304,15 +313,31 @@ static int stripe_end_io(struct dm_target *ti, struct bio *bio,
 	return error;
 }
 
+static int stripe_iterate_devices(struct dm_target *ti,
+				  iterate_devices_callout_fn fn, void *data)
+{
+	struct stripe_c *sc = ti->private;
+	int ret = 0;
+	unsigned i = 0;
+
+	do
+		ret = fn(ti, sc->stripe[i].dev,
+			 sc->stripe[i].physical_start, data);
+	while (!ret && ++i < sc->stripes);
+
+	return ret;
+}
+
 static struct target_type stripe_target = {
 	.name   = "striped",
-	.version = {1, 1, 0},
+	.version = {1, 2, 0},
 	.module = THIS_MODULE,
 	.ctr    = stripe_ctr,
 	.dtr    = stripe_dtr,
 	.map    = stripe_map,
 	.end_io = stripe_end_io,
 	.status = stripe_status,
+	.iterate_devices = stripe_iterate_devices,
 };
 
 int __init dm_stripe_init(void)

drivers/md/dm-sysfs.c

@@ -57,12 +57,21 @@ static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf)
 	return strlen(buf);
 }
 
+static ssize_t dm_attr_suspended_show(struct mapped_device *md, char *buf)
+{
+	sprintf(buf, "%d\n", dm_suspended(md));
+
+	return strlen(buf);
+}
+
 static DM_ATTR_RO(name);
 static DM_ATTR_RO(uuid);
+static DM_ATTR_RO(suspended);
 
 static struct attribute *dm_attrs[] = {
 	&dm_attr_name.attr,
 	&dm_attr_uuid.attr,
+	&dm_attr_suspended.attr,
 	NULL,
 };
 

include/linux/Kbuild

@@ -57,6 +57,7 @@ header-y += dlmconstants.h
 header-y += dlm_device.h
 header-y += dlm_netlink.h
 header-y += dm-ioctl.h
+header-y += dm-log-userspace.h
 header-y += dn.h
 header-y += dqblk_xfs.h
 header-y += efs_fs_sb.h