1 files changed, 34 insertions, 4 deletions

diff --git a/drivers/md/dm-log-userspace-base.c b/drivers/md/dm-log-userspace-base.c
index 1021c8986011..9429159d9ee3 100644
--- a/drivers/md/dm-log-userspace-base.c
+++ b/drivers/md/dm-log-userspace-base.c
@@ -9,6 +9,7 @@
 #include <linux/dm-dirty-log.h>
 #include <linux/device-mapper.h>
 #include <linux/dm-log-userspace.h>
+#include <linux/module.h>
 
 #include "dm-log-userspace-transfer.h"
 
@@ -30,6 +31,7 @@ struct flush_entry {
 
 struct log_c {
 	struct dm_target *ti;
+	struct dm_dev *log_dev;
 	uint32_t region_size;
 	region_t region_count;
 	uint64_t luid;
@@ -146,7 +148,7 @@ static int build_constructor_string(struct dm_target *ti,
  *	<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> clustered-disk <arg count> <log dev> <region_size> [[no]sync]
  *
  * So, this module will strip off the <UUID> for identification purposes
  * when communicating with userspace about a log; but will pass on everything
@@ -161,13 +163,15 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 	struct log_c *lc = NULL;
 	uint64_t rdata;
 	size_t rdata_size = sizeof(rdata);
+	char *devices_rdata = NULL;
+	size_t devices_rdata_size = DM_NAME_LEN;
 
 	if (argc < 3) {
 		DMWARN("Too few arguments to userspace dirty log");
 		return -EINVAL;
 	}
 
-	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
+	lc = kzalloc(sizeof(*lc), GFP_KERNEL);
 	if (!lc) {
 		DMWARN("Unable to allocate userspace log context.");
 		return -ENOMEM;
@@ -195,9 +199,19 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 		return str_size;
 	}
 
-	/* Send table string */
+	devices_rdata = kzalloc(devices_rdata_size, GFP_KERNEL);
+	if (!devices_rdata) {
+		DMERR("Failed to allocate memory for device information");
+		r = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * Send table string and get back any opened device.
+	 */
 	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_CTR,
-				 ctr_str, str_size, NULL, NULL);
+				 ctr_str, str_size,
+				 devices_rdata, &devices_rdata_size);
 
 	if (r < 0) {
 		if (r == -ESRCH)
@@ -220,7 +234,20 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
 	lc->region_size = (uint32_t)rdata;
 	lc->region_count = dm_sector_div_up(ti->len, lc->region_size);
 
+	if (devices_rdata_size) {
+		if (devices_rdata[devices_rdata_size - 1] != '\0') {
+			DMERR("DM_ULOG_CTR device return string not properly terminated");
+			r = -EINVAL;
+			goto out;
+		}
+		r = dm_get_device(ti, devices_rdata,
+				  dm_table_get_mode(ti->table), &lc->log_dev);
+		if (r)
+			DMERR("Failed to register %s with device-mapper",
+			      devices_rdata);
+	}
 out:
+	kfree(devices_rdata);
 	if (r) {
 		kfree(lc);
 		kfree(ctr_str);
@@ -241,6 +268,9 @@ static void userspace_dtr(struct dm_dirty_log *log)
 				 NULL, 0,
 				 NULL, NULL);
 
+	if (lc->log_dev)
+		dm_put_device(lc->ti, lc->log_dev);
+
 	kfree(lc->usr_argv_str);
 	kfree(lc);