Check duplicate backrefs for both data and metadata

lookup_inline_extent_backref only checks for duplicate backref for data extent.
It assumes backrefs for tree block never conflict.  This patch makes
lookup_inline_extent_backref check duplicate backrefs for both data and tree
block, so that we can detect potential bug earlier.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/extent-tree.c b/extent-tree.c
index 3ec57fa..b2f9bb2 100644 (file)
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -1061,12 +1061,6 @@ static int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
 #endif
        BUG_ON(item_size < sizeof(*ei));
 
-       if (owner < BTRFS_FIRST_FREE_OBJECTID && insert &&
-           item_size + extra_size >= BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
-               err = -EAGAIN;
-               goto out;
-       }
-
        ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
        flags = btrfs_extent_flags(leaf, ei);
 
@@ -1139,8 +1133,8 @@ static int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
                 * For simplicity, we just do not add new inline back
                 * ref if there is any back ref item.
                 */
-               if (owner >= BTRFS_FIRST_FREE_OBJECTID &&
-                   find_next_key(path, &key) == 0 && key.objectid == bytenr) {
+               if (find_next_key(path, &key) == 0 && key.objectid == bytenr &&
+                   key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
                        err = -EAGAIN;
                        goto out;
                }