diff --git a/NEWS b/NEWS
index 54a644ae7a82902da4a096db7742b05424e6c0e4..9cdf6448b041de07e8db4a7fdd8a36252eaff4da 100644
--- a/NEWS
+++ b/NEWS
@@ -37,6 +37,7 @@ documents those changes that are of interest to users and administrators.
  -- Fix proctrack/lua plugin to prevent possible deadlock.
  -- Prevent infinite loop in slurmstepd if execve fails.
  -- Prevent multiple responses to REQUEST_UPDATE_JOB_STEP message.
+ -- Prevent possible deadlock in acct_gather_filesystem/lustre on error.
 
 * Changes in Slurm 15.08.11
 ===========================
diff --git a/src/plugins/acct_gather_filesystem/lustre/acct_gather_filesystem_lustre.c b/src/plugins/acct_gather_filesystem/lustre/acct_gather_filesystem_lustre.c
index 10b4953cbcc8403019e83ddb63ed3a39cce315d4..77d2c088228083b5dfb93c1590cad71fd4233d51 100644
--- a/src/plugins/acct_gather_filesystem/lustre/acct_gather_filesystem_lustre.c
+++ b/src/plugins/acct_gather_filesystem/lustre/acct_gather_filesystem_lustre.c
@@ -310,6 +310,7 @@ static int _update_node_filesystem(void)
 		if (dataset_id == SLURM_ERROR) {
 			error("FileSystem: Failed to create the dataset "
 			      "for Lustre");
+			slurm_mutex_unlock(&lustre_lock);
 			return SLURM_ERROR;
 		}