From: Josef Bacik <josef@toxicpanda.com>
Date: Fri, 12 Mar 2021 15:25:19 -0500
Subject: btrfs: handle btrfs_update_reloc_root failure in prepare_to_merge
Git-commit: bbae13f8ab22fb997403ee8a67f87432f4751a8d
Patch-mainline: v5.13-rc1
References: bsc#1187833

btrfs_update_reloc_root will will return errors in the future, so handle
an error properly in prepare_to_merge.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/relocation.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2552,9 +2552,20 @@ again:
 		 */
 		if (!err)
 			btrfs_set_root_refs(&reloc_root->root_item, 1);
-		btrfs_update_reloc_root(trans, root);
+		ret = btrfs_update_reloc_root(trans, root);
 
+		/*
+		 * Even if we have an error we need this reloc root back on our
+		 * list so we can clean up properly.
+		 */
 		list_add(&reloc_root->root_list, &reloc_roots);
+
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			if (!err)
+				err = ret;
+			break;
+		}
 	}
 
 	list_splice(&reloc_roots, &rc->reloc_roots);