Merge tag 'dm-3.14-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device-mapper changes from Mike Snitzer:
 "A lot of attention was paid to improving the thin-provisioning
  target's handling of metadata operation failures and running out of
  space.  A new 'error_if_no_space' feature was added to allow users to
  error IOs rather than queue them when either the data or metadata
  space is exhausted.

  Additional fixes/features include:
   - a few fixes to properly support thin metadata device resizing
   - a solution for reliably waiting for a DM device's embedded kobject
     to be released before destroying the device
   - old dm-snapshot is updated to use the dm-bufio interface to take
     advantage of readahead capabilities that improve snapshot
     activation
   - new dm-cache target tunables to control how quickly data is
     promoted to the cache (fast) device
   - improved write efficiency of cluster mirror target by combining
     userspace flush and mark requests"

* tag 'dm-3.14-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (35 commits)
  dm log userspace: allow mark requests to piggyback on flush requests
  dm space map metadata: fix bug in resizing of thin metadata
  dm cache: add policy name to status output
  dm thin: fix pool feature parsing
  dm sysfs: fix a module unload race
  dm snapshot: use dm-bufio prefetch
  dm snapshot: use dm-bufio
  dm snapshot: prepare for switch to using dm-bufio
  dm snapshot: use GFP_KERNEL when initializing exceptions
  dm cache: add block sizes and total cache blocks to status output
  dm btree: add dm_btree_find_lowest_key
  dm space map metadata: fix extending the space map
  dm space map common: make sure new space is used during extend
  dm: wait until embedded kobject is released before destroying a device
  dm: remove pointless kobject comparison in dm_get_from_kobject
  dm snapshot: call destroy_work_on_stack() to pair with INIT_WORK_ONSTACK()
  dm cache policy mq: introduce three promotion threshold tunables
  dm cache policy mq: use list_del_init instead of list_del + INIT_LIST_HEAD
  dm thin: fix set_pool_mode exposed pool operation races
  dm thin: eliminate the no_free_space flag
  ...

1 files changed, 159 insertions, 47 deletions

diff --git a/drivers/md/dm-log-userspace-base.c b/drivers/md/dm-log-userspace-base.c
index 9429159d9ee3..b953db6cc229 100644
--- a/drivers/md/dm-log-userspace-base.c
+++ b/drivers/md/dm-log-userspace-base.c
@@ -10,10 +10,11 @@
 #include <linux/device-mapper.h>
 #include <linux/dm-log-userspace.h>
 #include <linux/module.h>
+#include <linux/workqueue.h>
 
 #include "dm-log-userspace-transfer.h"
 
-#define DM_LOG_USERSPACE_VSN "1.1.0"
+#define DM_LOG_USERSPACE_VSN "1.3.0"
 
 struct flush_entry {
 	int type;
@@ -58,6 +59,18 @@ struct log_c {
 	spinlock_t flush_lock;
 	struct list_head mark_list;
 	struct list_head clear_list;
+
+	/*
+	 * Workqueue for flush of clear region requests.
+	 */
+	struct workqueue_struct *dmlog_wq;
+	struct delayed_work flush_log_work;
+	atomic_t sched_flush;
+
+	/*
+	 * Combine userspace flush and mark requests for efficiency.
+	 */
+	uint32_t integrated_flush;
 };
 
 static mempool_t *flush_entry_pool;
@@ -122,6 +135,9 @@ static int build_constructor_string(struct dm_target *ti,
 
 	*ctr_str = NULL;
 
+	/*
+	 * Determine overall size of the string.
+	 */
 	for (i = 0, str_size = 0; i < argc; i++)
 		str_size += strlen(argv[i]) + 1; /* +1 for space between args */
 
@@ -141,18 +157,39 @@ static int build_constructor_string(struct dm_target *ti,
 	return str_size;
 }
 
+static void do_flush(struct work_struct *work)
+{
+	int r;
+	struct log_c *lc = container_of(work, struct log_c, flush_log_work.work);
+
+	atomic_set(&lc->sched_flush, 0);
+
+	r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH, NULL, 0, NULL, NULL);
+
+	if (r)
+		dm_table_event(lc->ti->table);
+}
+
 /*
  * userspace_ctr
  *
  * argv contains:
- *	<UUID> <other args>
- * Where 'other args' is the userspace implementation specific log
- * arguments.  An example might be:
- *	<UUID> clustered-disk <arg count> <log dev> <region_size> [[no]sync]
+ *	<UUID> [integrated_flush] <other args>
+ * Where 'other args' are the userspace implementation-specific log
+ * arguments.
+ *
+ * Example:
+ *	<UUID> [integrated_flush] clustered-disk <arg count> <log dev>
+ *	<region_size> [[no]sync]
+ *
+ * This module strips off the <UUID> and uses it for identification
+ * purposes when communicating with userspace about a log.
  *
- * So, this module will strip off the <UUID> for identification purposes
- * when communicating with userspace about a log; but will pass on everything
- * else.
+ * If integrated_flush is defined, the kernel combines flush
+ * and mark requests.
+ *
+ * The rest of the line, beginning with 'clustered-disk', is passed
+ * to the userspace ctr function.
  */
 static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 			 unsigned argc, char **argv)
@@ -188,12 +225,22 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 		return -EINVAL;
 	}
 
+	lc->usr_argc = argc;
+
 	strncpy(lc->uuid, argv[0], DM_UUID_LEN);
+	argc--;
+	argv++;
 	spin_lock_init(&lc->flush_lock);
 	INIT_LIST_HEAD(&lc->mark_list);
 	INIT_LIST_HEAD(&lc->clear_list);
 
-	str_size = build_constructor_string(ti, argc - 1, argv + 1, &ctr_str);
+	if (!strcasecmp(argv[0], "integrated_flush")) {
+		lc->integrated_flush = 1;
+		argc--;
+		argv++;
+	}
+
+	str_size = build_constructor_string(ti, argc, argv, &ctr_str);
 	if (str_size < 0) {
 		kfree(lc);
 		return str_size;
@@ -246,6 +293,19 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 			DMERR("Failed to register %s with device-mapper",
 			      devices_rdata);
 	}
+
+	if (lc->integrated_flush) {
+		lc->dmlog_wq = alloc_workqueue("dmlogd", WQ_MEM_RECLAIM, 0);
+		if (!lc->dmlog_wq) {
+			DMERR("couldn't start dmlogd");
+			r = -ENOMEM;
+			goto out;
+		}
+
+		INIT_DELAYED_WORK(&lc->flush_log_work, do_flush);
+		atomic_set(&lc->sched_flush, 0);
+	}
+
 out:
 	kfree(devices_rdata);
 	if (r) {
@@ -253,7 +313,6 @@ out:
 		kfree(ctr_str);
 	} else {
 		lc->usr_argv_str = ctr_str;
-		lc->usr_argc = argc;
 		log->context = lc;
 	}
 
@@ -264,9 +323,16 @@ static void userspace_dtr(struct dm_dirty_log *log)
 {
 	struct log_c *lc = log->context;
 
+	if (lc->integrated_flush) {
+		/* flush workqueue */
+		if (atomic_read(&lc->sched_flush))
+			flush_delayed_work(&lc->flush_log_work);
+
+		destroy_workqueue(lc->dmlog_wq);
+	}
+
 	(void) dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_DTR,
-				 NULL, 0,
-				 NULL, NULL);
+				    NULL, 0, NULL, NULL);
 
 	if (lc->log_dev)
 		dm_put_device(lc->ti, lc->log_dev);
@@ -283,8 +349,7 @@ static int userspace_presuspend(struct dm_dirty_log *log)
 	struct log_c *lc = log->context;
 
 	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_PRESUSPEND,
-				 NULL, 0,
-				 NULL, NULL);
+				 NULL, 0, NULL, NULL);
 
 	return r;
 }
@@ -294,9 +359,14 @@ static int userspace_postsuspend(struct dm_dirty_log *log)
 	int r;
 	struct log_c *lc = log->context;
 
+	/*
+	 * Run planned flush earlier.
+	 */
+	if (lc->integrated_flush && atomic_read(&lc->sched_flush))
+		flush_delayed_work(&lc->flush_log_work);
+
 	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_POSTSUSPEND,
-				 NULL, 0,
-				 NULL, NULL);
+				 NULL, 0, NULL, NULL);
 
 	return r;
 }
@@ -308,8 +378,7 @@ static int userspace_resume(struct dm_dirty_log *log)
 
 	lc->in_sync_hint = 0;
 	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_RESUME,
-				 NULL, 0,
-				 NULL, NULL);
+				 NULL, 0, NULL, NULL);
 
 	return r;
 }
@@ -405,7 +474,8 @@ static int flush_one_by_one(struct log_c *lc, struct list_head *flush_list)
 	return r;
 }
 
-static int flush_by_group(struct log_c *lc, struct list_head *flush_list)
+static int flush_by_group(struct log_c *lc, struct list_head *flush_list,
+			  int flush_with_payload)
 {
 	int r = 0;
 	int count;
@@ -431,15 +501,29 @@ static int flush_by_group(struct log_c *lc, struct list_head *flush_list)
 				break;
 		}
 
-		r = userspace_do_request(lc, lc->uuid, type,
-					 (char *)(group),
-					 count * sizeof(uint64_t),
-					 NULL, NULL);
-		if (r) {
-			/* Group send failed.  Attempt one-by-one. */
-			list_splice_init(&tmp_list, flush_list);
-			r = flush_one_by_one(lc, flush_list);
-			break;
+		if (flush_with_payload) {
+			r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
+						 (char *)(group),
+						 count * sizeof(uint64_t),
+						 NULL, NULL);
+			/*
+			 * Integrated flush failed.
+			 */
+			if (r)
+				break;
+		} else {
+			r = userspace_do_request(lc, lc->uuid, type,
+						 (char *)(group),
+						 count * sizeof(uint64_t),
+						 NULL, NULL);
+			if (r) {
+				/*
+				 * Group send failed.  Attempt one-by-one.
+				 */
+				list_splice_init(&tmp_list, flush_list);
+				r = flush_one_by_one(lc, flush_list);
+				break;
+			}
 		}
 	}
 
@@ -476,6 +560,8 @@ static int userspace_flush(struct dm_dirty_log *log)
 	struct log_c *lc = log->context;
 	LIST_HEAD(mark_list);
 	LIST_HEAD(clear_list);
+	int mark_list_is_empty;
+	int clear_list_is_empty;
 	struct flush_entry *fe, *tmp_fe;
 
 	spin_lock_irqsave(&lc->flush_lock, flags);
@@ -483,23 +569,51 @@ static int userspace_flush(struct dm_dirty_log *log)
 	list_splice_init(&lc->clear_list, &clear_list);
 	spin_unlock_irqrestore(&lc->flush_lock, flags);
 
-	if (list_empty(&mark_list) && list_empty(&clear_list))
+	mark_list_is_empty = list_empty(&mark_list);
+	clear_list_is_empty = list_empty(&clear_list);
+
+	if (mark_list_is_empty && clear_list_is_empty)
 		return 0;
 
-	r = flush_by_group(lc, &mark_list);
+	r = flush_by_group(lc, &clear_list, 0);
 	if (r)
-		goto fail;
+		goto out;
 
-	r = flush_by_group(lc, &clear_list);
+	if (!lc->integrated_flush) {
+		r = flush_by_group(lc, &mark_list, 0);
+		if (r)
+			goto out;
+		r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
+					 NULL, 0, NULL, NULL);
+		goto out;
+	}
+
+	/*
+	 * Send integrated flush request with mark_list as payload.
+	 */
+	r = flush_by_group(lc, &mark_list, 1);
 	if (r)
-		goto fail;
+		goto out;
 
-	r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
-				 NULL, 0, NULL, NULL);
+	if (mark_list_is_empty && !atomic_read(&lc->sched_flush)) {
+		/*
+		 * When there are only clear region requests,
+		 * we schedule a flush in the future.
+		 */
+		queue_delayed_work(lc->dmlog_wq, &lc->flush_log_work, 3 * HZ);
+		atomic_set(&lc->sched_flush, 1);
+	} else {
+		/*
+		 * Cancel pending flush because we
+		 * have already flushed in mark_region.
+		 */
+		cancel_delayed_work(&lc->flush_log_work);
+		atomic_set(&lc->sched_flush, 0);
+	}
 
-fail:
+out:
 	/*
-	 * We can safely remove these entries, even if failure.
+	 * We can safely remove these entries, even after failure.
 	 * Calling code will receive an error and will know that
 	 * the log facility has failed.
 	 */
@@ -603,8 +717,7 @@ static int userspace_get_resync_work(struct dm_dirty_log *log, region_t *region)
 
 	rdata_size = sizeof(pkg);
 	r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_RESYNC_WORK,
-				 NULL, 0,
-				 (char *)&pkg, &rdata_size);
+				 NULL, 0, (char *)&pkg, &rdata_size);
 
 	*region = pkg.r;
 	return (r) ? r : (int)pkg.i;
@@ -630,8 +743,7 @@ static void userspace_set_region_sync(struct dm_dirty_log *log,
 	pkg.i = (int64_t)in_sync;
 
 	r = userspace_do_request(lc, lc->uuid, DM_ULOG_SET_REGION_SYNC,
-				 (char *)&pkg, sizeof(pkg),
-				 NULL, NULL);
+				 (char *)&pkg, sizeof(pkg), NULL, NULL);
 
 	/*
 	 * It would be nice to be able to report failures.
@@ -657,8 +769,7 @@ static region_t userspace_get_sync_count(struct dm_dirty_log *log)
 
 	rdata_size = sizeof(sync_count);
 	r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_SYNC_COUNT,
-				 NULL, 0,
-				 (char *)&sync_count, &rdata_size);
+				 NULL, 0, (char *)&sync_count, &rdata_size);
 
 	if (r)
 		return 0;
@@ -685,8 +796,7 @@ static int userspace_status(struct dm_dirty_log *log, status_type_t status_type,
 	switch (status_type) {
 	case STATUSTYPE_INFO:
 		r = userspace_do_request(lc, lc->uuid, DM_ULOG_STATUS_INFO,
-					 NULL, 0,
-					 result, &sz);
+					 NULL, 0, result, &sz);
 
 		if (r) {
 			sz = 0;
@@ -699,8 +809,10 @@ static int userspace_status(struct dm_dirty_log *log, status_type_t status_type,
 		BUG_ON(!table_args); /* There will always be a ' ' */
 		table_args++;
 
-		DMEMIT("%s %u %s %s ", log->type->name, lc->usr_argc,
-		       lc->uuid, table_args);
+		DMEMIT("%s %u %s ", log->type->name, lc->usr_argc, lc->uuid);
+		if (lc->integrated_flush)
+			DMEMIT("integrated_flush ");
+		DMEMIT("%s ", table_args);
 		break;
 	}
 	return (r) ? 0 : (int)sz;