nilfs2: zero fill unused portion of super root block

The super root block is newly-allocated each time it is written back
to disk, so unused portion of the block should be cleared.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 2cc8c087b2d5..699170e0f308 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -596,6 +596,16 @@ void nilfs_write_inode_common(struct inode *inode,
         raw_inode->i_flags = cpu_to_le32(ii->i_flags);
         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
 
+        if (NILFS_ROOT_METADATA_FILE(inode->i_ino)) {
+                struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+
+                /* zero-fill unused portion in the case of super root block */
+                raw_inode->i_xattr = 0;
+                raw_inode->i_pad = 0;
+                memset((void *)raw_inode + sizeof(*raw_inode), 0,
+                       nilfs->ns_inode_size - sizeof(*raw_inode));
+        }
+
         if (has_bmap)
                 nilfs_bmap_write(ii->i_bmap, raw_inode);
         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))