[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/autofs4/root.c b/fs/autofs4/root.c
index e21bb46..c149352 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -638,7 +638,7 @@
 	dput(ino->dentry);
 
 	dentry->d_inode->i_size = 0;
-	dentry->d_inode->i_nlink = 0;
+	clear_nlink(dentry->d_inode);
 
 	dir->i_mtime = CURRENT_TIME;
 
@@ -673,7 +673,7 @@
 	}
 	dput(ino->dentry);
 	dentry->d_inode->i_size = 0;
-	dentry->d_inode->i_nlink = 0;
+	clear_nlink(dentry->d_inode);
 
 	if (dir->i_nlink)
 		drop_nlink(dir);