From a9b1fc851db054ddec703dc7951ed00620600b26 Mon Sep 17 00:00:00 2001
From: Liu Bo <bo.li.liu@oracle.com>
Date: Wed, 31 Aug 2016 16:43:33 -0700
Subject: Btrfs: fix endless loop in balancing block groups

Qgroup function may overwrite the saved error 'err' with 0
in case quota is not enabled, and this ends up with a
endless loop in balance because we keep going back to balance
the same block group.

It really should use 'ret' instead.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 8a2c2a0..c0c13dc 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4200,9 +4200,11 @@ restart:
 		err = PTR_ERR(trans);
 		goto out_free;
 	}
-	err = qgroup_fix_relocated_data_extents(trans, rc);
-	if (err < 0) {
-		btrfs_abort_transaction(trans, err);
+	ret = qgroup_fix_relocated_data_extents(trans, rc);
+	if (ret < 0) {
+		btrfs_abort_transaction(trans, ret);
+		if (!err)
+			err = ret;
 		goto out_free;
 	}
 	btrfs_commit_transaction(trans, rc->extent_root);
-- 
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