btrfs: clean_tree_block should panic on observed memory corruption and return void

 The only error condition in clean_tree_block is an accounting bug.
 Returning without modifying dirty_metadata_bytes and as if the cleaning
 as been performed may cause problems later so it should panic instead.

 It should probably be a BUG_ON but we have btrfs_panic now.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>

1 files changed, 10 insertions, 5 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 534266fe505f..d52ec1155204 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1109,8 +1109,8 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 
 }
 
-int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-                     struct extent_buffer *buf)
+void clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+                      struct extent_buffer *buf)
 {
         struct inode *btree_inode = root->fs_info->btree_inode;
         if (btrfs_header_generation(buf) ==
@@ -1121,8 +1121,14 @@ int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                         spin_lock(&root->fs_info->delalloc_lock);
                         if (root->fs_info->dirty_metadata_bytes >= buf->len)
                                 root->fs_info->dirty_metadata_bytes -= buf->len;
-                        else
-                                WARN_ON(1);
+                        else {
+                                spin_unlock(&root->fs_info->delalloc_lock);
+                                btrfs_panic(root->fs_info, -EOVERFLOW,
+                                          "Can't clear %lu bytes from "
+                                          " dirty_mdatadata_bytes (%lu)",
+                                          buf->len,
+                                          root->fs_info->dirty_metadata_bytes);
+                        }
                         spin_unlock(&root->fs_info->delalloc_lock);
                 }
 
@@ -1131,7 +1137,6 @@ int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
                                           buf);
         }
-        return 0;
 }
 
 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,