[PATCH] initialize parts of udf inode earlier in create

Eric says:

> I saw an oops down this path when trying to create a new file on a UDF
> filesystem which was internally marked as readonly, but mounted rw:
>
> udf_create
>         udf_new_inode
>                 new_inode
>                         alloc_inode
>                         	udf_alloc_inode
>                 udf_new_block
>                         returns EIO due to readonlyness
>                 iput (on error)

I ran into the same issue today, but when listing a directory with
invalid/corrupt entries:

udf_lookup
        udf_iget
                get_new_inode_fast
                        alloc_inode
                                udf_alloc_inode
                __udf_read_inode
                        fails for any reason
                iput (on error)
                        ...

The following patch to udf_alloc_inode() should take care of both (and
other similar) cases, but I've only tested it with udf_lookup().
Signed-off-by: Dan Bastone <dan@pwienterprises.com>
Cc: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

fs/udf/super.c

@@ -115,6 +115,13 @@ static struct inode *udf_alloc_inode(struct super_block *sb)
 	ei = (struct udf_inode_info *)kmem_cache_alloc(udf_inode_cachep, SLAB_KERNEL);
 	if (!ei)
 		return NULL;
+
+	ei->i_unique = 0;
+	ei->i_lenExtents = 0;
+	ei->i_next_alloc_block = 0;
+	ei->i_next_alloc_goal = 0;
+	ei->i_strat4096 = 0;
+
 	return &ei->vfs_inode;
 }