+#define CORRUPT(reason, eb, root, slot) \
+ printk(KERN_CRIT "btrfs: corrupt leaf, %s: block=%llu," \
+ "root=%llu, slot=%d\n", reason, \
+ (unsigned long long)btrfs_header_bytenr(eb), \
+ (unsigned long long)root->objectid, slot)
+
+static noinline int check_leaf(struct btrfs_root *root,
+ struct extent_buffer *leaf)
+{
+ struct btrfs_key key;
+ struct btrfs_key leaf_key;
+ u32 nritems = btrfs_header_nritems(leaf);
+ int slot;
+
+ if (nritems == 0)
+ return 0;
+
+ /* Check the 0 item */
+ if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
+ BTRFS_LEAF_DATA_SIZE(root)) {
+ CORRUPT("invalid item offset size pair", leaf, root, 0);
+ return -EIO;
+ }
+
+ /*
+ * Check to make sure each items keys are in the correct order and their
+ * offsets make sense. We only have to loop through nritems-1 because
+ * we check the current slot against the next slot, which verifies the
+ * next slot's offset+size makes sense and that the current's slot
+ * offset is correct.
+ */
+ for (slot = 0; slot < nritems - 1; slot++) {
+ btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
+ btrfs_item_key_to_cpu(leaf, &key, slot + 1);
+
+ /* Make sure the keys are in the right order */
+ if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
+ CORRUPT("bad key order", leaf, root, slot);
+ return -EIO;
+ }
+
+ /*
+ * Make sure the offset and ends are right, remember that the
+ * item data starts at the end of the leaf and grows towards the
+ * front.
+ */
+ if (btrfs_item_offset_nr(leaf, slot) !=
+ btrfs_item_end_nr(leaf, slot + 1)) {
+ CORRUPT("slot offset bad", leaf, root, slot);
+ return -EIO;
+ }
+
+ /*
+ * Check to make sure that we don't point outside of the leaf,
+ * just incase all the items are consistent to eachother, but
+ * all point outside of the leaf.
+ */
+ if (btrfs_item_end_nr(leaf, slot) >
+ BTRFS_LEAF_DATA_SIZE(root)) {
+ CORRUPT("slot end outside of leaf", leaf, root, slot);
+ return -EIO;
+ }
+ }
+
+ return 0;
+}
+