1 files changed, 2 insertions, 0 deletions

diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index 298631eaee78..8428db7cd88f 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -761,12 +761,14 @@ static void __reada_start_machine(struct btrfs_fs_info *fs_info)
 
         do {
                 enqueued = 0;
+                mutex_lock(&fs_devices->device_list_mutex);
                 list_for_each_entry(device, &fs_devices->devices, dev_list) {
                         if (atomic_read(&device->reada_in_flight) <
                             MAX_IN_FLIGHT)
                                 enqueued += reada_start_machine_dev(fs_info,
                                                                     device);
                 }
+                mutex_unlock(&fs_devices->device_list_mutex);
                 total += enqueued;
         } while (enqueued && total < 10000);