+/*
+ * blocked until all flighting bios are finished.
+ */
+static void btrfs_rm_dev_replace_blocked(struct btrfs_fs_info *fs_info)
+{
+ s64 writers;
+ DEFINE_WAIT(wait);
+
+ set_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
+ do {
+ prepare_to_wait(&fs_info->replace_wait, &wait,
+ TASK_UNINTERRUPTIBLE);
+ writers = percpu_counter_sum(&fs_info->bio_counter);
+ if (writers)
+ schedule();
+ finish_wait(&fs_info->replace_wait, &wait);
+ } while (writers);
+}
+
+/*
+ * we have removed target device, it is safe to allow new bios request.
+ */
+static void btrfs_rm_dev_replace_unblocked(struct btrfs_fs_info *fs_info)
+{
+ clear_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
+ if (waitqueue_active(&fs_info->replace_wait))
+ wake_up(&fs_info->replace_wait);
+}
+