Btrfs: resume balance on rw (re)mounts properly

This introduces btrfs_resume_balance_async(), which, given that
restriper state was recovered earlier by btrfs_recover_balance(),
resumes balance in btrfs-balance kthread.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 15 insertions, 9 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 3a7961ba161e..8cc47103a32e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2490,17 +2490,23 @@ retry_root_backup:
                 goto fail_trans_kthread;
         }
 
-        if (!(sb->s_flags & MS_RDONLY)) {
-                down_read(&fs_info->cleanup_work_sem);
-                err = btrfs_orphan_cleanup(fs_info->fs_root);
-                if (!err)
-                        err = btrfs_orphan_cleanup(fs_info->tree_root);
+        if (sb->s_flags & MS_RDONLY)
+                return 0;
+
+        down_read(&fs_info->cleanup_work_sem);
+        if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
+            (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
                 up_read(&fs_info->cleanup_work_sem);
+                close_ctree(tree_root);
+                return ret;
+        }
+        up_read(&fs_info->cleanup_work_sem);
 
-                if (err) {
-                        close_ctree(tree_root);
-                        return err;
-                }
+        ret = btrfs_resume_balance_async(fs_info);
+        if (ret) {
+                printk(KERN_WARNING "btrfs: failed to resume balance\n");
+                close_ctree(tree_root);
+                return ret;
         }
 
         return 0;