ext4: disallow hard-linked directory in ext4_lookup

A hard-linked directory to its parent can cause the VFS to deadlock,
and is a sign of a corrupted file system.  So detect this case in
ext4_lookup(), before the rmdir() lockup scenario can take place.

Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
This commit is contained in:
Andreas Dilger 2012-05-28 17:02:25 -04:00 committed by Theodore Ts'o
parent 967ac8af44
commit 7e936b7372

View File

@ -1330,6 +1330,12 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, stru
EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
return ERR_PTR(-EIO);
}
if (unlikely(ino == dir->i_ino)) {
EXT4_ERROR_INODE(dir, "'%.*s' linked to parent dir",
dentry->d_name.len,
dentry->d_name.name);
return ERR_PTR(-EIO);
}
inode = ext4_iget(dir->i_sb, ino);
if (inode == ERR_PTR(-ESTALE)) {
EXT4_ERROR_INODE(dir,