btrfs: tree-checker: don't fail on empty extent roots for extent tree v2

For extent tree v2 we can definitely have empty extent roots, so skip
this particular check if we have that set.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index aae5697dde329325c412fe5a8ba203ffb5358f54..64c7d2a2bb3e4244b9bc02e49a8f44e489c0f052 100644 (file)
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -1648,7 +1648,6 @@ static int check_leaf(struct extent_buffer *leaf, bool check_item_data)
                /* These trees must never be empty */
                if (unlikely(owner == BTRFS_ROOT_TREE_OBJECTID ||
                             owner == BTRFS_CHUNK_TREE_OBJECTID ||
-                            owner == BTRFS_EXTENT_TREE_OBJECTID ||
                             owner == BTRFS_DEV_TREE_OBJECTID ||
                             owner == BTRFS_FS_TREE_OBJECTID ||
                             owner == BTRFS_DATA_RELOC_TREE_OBJECTID)) {
@@ -1657,12 +1656,25 @@ static int check_leaf(struct extent_buffer *leaf, bool check_item_data)
                                    owner);
                        return -EUCLEAN;
                }
+
                /* Unknown tree */
                if (unlikely(owner == 0)) {
                        generic_err(leaf, 0,
                                "invalid owner, root 0 is not defined");
                        return -EUCLEAN;
                }
+
+               /* EXTENT_TREE_V2 can have empty extent trees. */
+               if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2))
+                       return 0;
+
+               if (unlikely(owner == BTRFS_EXTENT_TREE_OBJECTID)) {
+                       generic_err(leaf, 0,
+                       "invalid root, root %llu must never be empty",
+                                   owner);
+                       return -EUCLEAN;
+               }
+
                return 0;
        }