Btrfs: fix race setting up and completing qgroup rescan workers

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / fs / btrfs / qgroup.c

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 90e29d4..734babb 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2328,9 +2328,6 @@ out:
        btrfs_free_path(path);
 
        mutex_lock(&fs_info->qgroup_rescan_lock);
-       if (!btrfs_fs_closing(fs_info))
-               fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
-
        if (err > 0 &&
            fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
                fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
@@ -2346,16 +2343,30 @@ out:
        trans = btrfs_start_transaction(fs_info->quota_root, 1);
        if (IS_ERR(trans)) {
                err = PTR_ERR(trans);
+               trans = NULL;
                btrfs_err(fs_info,
                          "fail to start transaction for status update: %d\n",
                          err);
-               goto done;
        }
-       ret = update_qgroup_status_item(trans, fs_info, fs_info->quota_root);
-       if (ret < 0) {
-               err = ret;
-               btrfs_err(fs_info, "fail to update qgroup status: %d\n", err);
+
+       mutex_lock(&fs_info->qgroup_rescan_lock);
+       if (!btrfs_fs_closing(fs_info))
+               fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
+       if (trans) {
+               ret = update_qgroup_status_item(trans, fs_info, fs_info->quota_root);
+               if (ret < 0) {
+                       err = ret;
+                       btrfs_err(fs_info, "fail to update qgroup status: %d",
+                                 err);
+               }
        }
+       fs_info->qgroup_rescan_running = false;
+       complete_all(&fs_info->qgroup_rescan_completion);
+       mutex_unlock(&fs_info->qgroup_rescan_lock);
+
+       if (!trans)
+               return;
+
        btrfs_end_transaction(trans, fs_info->quota_root);
 
        if (btrfs_fs_closing(fs_info)) {
@@ -2366,12 +2377,6 @@ out:
        } else {
                btrfs_err(fs_info, "qgroup scan failed with %d", err);
        }
-
-done:
-       mutex_lock(&fs_info->qgroup_rescan_lock);
-       fs_info->qgroup_rescan_running = false;
-       mutex_unlock(&fs_info->qgroup_rescan_lock);
-       complete_all(&fs_info->qgroup_rescan_completion);
 }
 
 /*