[PATCH] r/o bind mounts: monitor zeroing of i_nlink

Some filesystems, instead of simply decrementing i_nlink, simply zero it
during an unlink operation.  We need to catch these in addition to the
decrement operations.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/hpfs/namei.c b/fs/hpfs/namei.c
index 25dd6f8..2507e73 100644
--- a/fs/hpfs/namei.c
+++ b/fs/hpfs/namei.c
@@ -495,7 +495,7 @@
 		break;
 	default:
 		drop_nlink(dir);
-		inode->i_nlink = 0;
+		clear_nlink(inode);
 		err = 0;
 	}
 	goto out;
@@ -590,7 +590,7 @@
 		int r;
 		if ((r = hpfs_remove_dirent(old_dir, dno, dep, &qbh, 1)) != 2) {
 			if ((nde = map_dirent(new_dir, hpfs_i(new_dir)->i_dno, (char *)new_name, new_len, NULL, &qbh1))) {
-				new_inode->i_nlink = 0;
+				clear_nlink(new_inode);
 				copy_de(nde, &de);
 				memcpy(nde->name, new_name, new_len);
 				hpfs_mark_4buffers_dirty(&qbh1);