Btrfs: zero unused bytes in inode item

The otime field is not zeroed, so users will see random otime in an old filesystem with a new kernel which has otime support in the future. The reserved bytes are also not zeroed, and we'll have compatibility issue if we make use of those bytes. Signed-off-by: Li Zefan <lizefan@huawei.com>
git-mirror · Jul 23, 2012 · 293f7e0 · 293f7e0
1 parent b4d7c3c
commit 293f7e0
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diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
@@ -62,6 +62,7 @@ static inline void btrfs_init_delayed_node(
 	INIT_LIST_HEAD(&delayed_node->n_list);
 	INIT_LIST_HEAD(&delayed_node->p_list);
 	delayed_node->bytes_reserved = 0;
+	memset(&delayed_node->inode_item, 0, sizeof(delayed_node->inode_item));
 }
 
 static inline int btrfs_is_continuous_delayed_item(

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
@@ -4693,6 +4693,8 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 	inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 				  struct btrfs_inode_item);
+	memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
+			     sizeof(*inode_item));
 	fill_inode_item(trans, path->nodes[0], inode_item, inode);
 
 	ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,