Btrfs: add a extent ref verify tool

We were having corruption issues that were tied back to problems with
the extent tree.  In order to track them down I built this tool to try
and find the culprit, which was pretty successful.  If you compile with
this tool on it will live verify every ref update that the fs makes and
make sure it is consistent and valid.  I've run this through with
xfstests and haven't gotten any false positives.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update error messages, add fixup from Dan Carpenter to handle errors
  of read_tree_block ]
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/fs/btrfs/ref-verify.h b/fs/btrfs/ref-verify.h
new file mode 100644
index 000000000000..3bf02ce0e1e2
--- /dev/null
+++ b/fs/btrfs/ref-verify.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2014 Facebook.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+#ifndef __REF_VERIFY__
+#define __REF_VERIFY__
+
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info);
+void btrfs_free_ref_cache(struct btrfs_fs_info *fs_info);
+int btrfs_ref_tree_mod(struct btrfs_root *root, u64 bytenr, u64 num_bytes,
+		       u64 parent, u64 ref_root, u64 owner, u64 offset,
+		       int action);
+void btrfs_free_ref_tree_range(struct btrfs_fs_info *fs_info, u64 start,
+			       u64 len);
+
+static inline void btrfs_init_ref_verify(struct btrfs_fs_info *fs_info)
+{
+	spin_lock_init(&fs_info->ref_verify_lock);
+	fs_info->block_tree = RB_ROOT;
+}
+#else
+static inline int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
+{
+	return 0;
+}
+
+static inline void btrfs_free_ref_cache(struct btrfs_fs_info *fs_info)
+{
+}
+
+static inline int btrfs_ref_tree_mod(struct btrfs_root *root, u64 bytenr,
+				     u64 num_bytes, u64 parent, u64 ref_root,
+				     u64 owner, u64 offset, int action)
+{
+	return 0;
+}
+
+static inline void btrfs_free_ref_tree_range(struct btrfs_fs_info *fs_info,
+					     u64 start, u64 len)
+{
+}
+
+static inline void btrfs_init_ref_verify(struct btrfs_fs_info *fs_info)
+{
+}
+
+#endif /* CONFIG_BTRFS_FS_REF_VERIFY */
+#endif /* _REF_VERIFY__ */