[Jfs-discussion] [CHECKER] Return Error code gets treated as dir_table index, resulting losses of other dir entries (JFS2.4, kernel 2.4.19)

[Junfeng Y. <yj...@st...>]

static function add_index can fail by return -EPERM (and it is declared to
return a unsigned 4-byte integer).  This error gets ignored by the caller,
dtInsertEntry, which will treat the returned error code (u32)(-EPERM) as
an index to dir_table.  This causes losses of directory entries in the
same parent directory.

static u32 add_index(tid_t tid, struct inode *ip, s64 bn, int slot)
{
...
		if ((mp = get_index_page(ip, 0)) == 0) {
			jfs_err("add_index: get_metapage failed!");
			xtTruncate(tid, ip, 0, COMMIT_PWMAP);
Return -->		return -EPERM;
...
}


static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
			  ddata_t * data, struct dt_lock ** dtlock)
{
...
Error -->		  lh->index = cpu_to_le32(add_index(data->leaf.tid,
							  data->leaf.ip,
							  bn, index));
...
}


Here is a trace:

============ Filesystem Image Before System Call ===================
4 files, 1 dirs, 6 nodes
[0:D]
  [1:F:1073741824]
  [2:F:0]
  [3:F:0]
  [4:D]

create file 5 succeeded.
can't get dir entry Input/output error
ERROR: Filesystem images differ

============= Filesystem Image After System Call ===================
3 files, 0 dirs, 4 nodes
[0:D]
  [1:F:1073741824]
  [2:F:0]
  [3:F:0]