ext4: add ext4_iget_normal() which is to be used for dir tree lookups

If there is a corrupted file system which has directory entries that
point at reserved, metadata inodes, prohibit them from being used by
treating them the same way we treat Boot Loader inodes --- that is,
mark them to be bad inodes.  This prohibits them from being opened,
deleted, or modified via chmod, chown, utimes, etc.

In particular, this prevents a corrupted file system which has a
directory entry which points at the journal inode from being deleted
and its blocks released, after which point Much Hilarity Ensues.

Reported-by: Sami Liedes <sami.liedes@iki.fi>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index a2a9d40522d2..7037ecf0fc23 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1417,7 +1417,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
                                          dentry);
                         return ERR_PTR(-EIO);
                 }
-                inode = ext4_iget(dir->i_sb, ino);
+                inode = ext4_iget_normal(dir->i_sb, ino);
                 if (inode == ERR_PTR(-ESTALE)) {
                         EXT4_ERROR_INODE(dir,
                                          "deleted inode referenced: %u",
@@ -1450,7 +1450,7 @@ struct dentry *ext4_get_parent(struct dentry *child)
                 return ERR_PTR(-EIO);
         }
 
-        return d_obtain_alias(ext4_iget(child->d_inode->i_sb, ino));
+        return d_obtain_alias(ext4_iget_normal(child->d_inode->i_sb, ino));
 }
 
 /*