Btrfs: fix loading of orphan roots leading to BUG_ON

[cascardo/linux.git] / fs / btrfs / root-tree.c

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 7cf8509..2c849b0 100644 (file)
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -310,8 +310,16 @@ int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
                set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
 
                err = btrfs_insert_fs_root(root->fs_info, root);
+               /*
+                * The root might have been inserted already, as before we look
+                * for orphan roots, log replay might have happened, which
+                * triggers a transaction commit and qgroup accounting, which
+                * in turn reads and inserts fs roots while doing backref
+                * walking.
+                */
+               if (err == -EEXIST)
+                       err = 0;
                if (err) {
-                       BUG_ON(err == -EEXIST);
                        btrfs_free_fs_root(root);
                        break;
                }