hfsplus: fix rename over directories

When renaming over a directory we need to use hfsplus_rmdir instead of
hfsplus_unlink to evict the victim.  This makes sure we properly error out
on non-empty directory as required by Posix (BZ #16571), and it also makes
sure we do the right thing in case i_nlink will every be set correctly for
directories on hfsplus.

Reported-by: Vlado Plaga <rechner@vlado-do.de>
Signed-off-by: Christoph Hellwig <hch@tuxera.com>

fs/hfsplus/dir.c

@@ -452,7 +452,10 @@ static int hfsplus_rename(struct inode *old_dir, struct dentry *old_dentry,
 
 	/* Unlink destination if it already exists */
 	if (new_dentry->d_inode) {
-		res = hfsplus_unlink(new_dir, new_dentry);
+		if (S_ISDIR(new_dentry->d_inode->i_mode))
+			res = hfsplus_rmdir(new_dir, new_dentry);
+		else
+			res = hfsplus_unlink(new_dir, new_dentry);
 		if (res)
 			return res;
 	}