kern/73148: cannot chmod mount point for read-only filesystem

[Gregory Bond]

The following reply was made to PR kern/73148; it has been noted by GNATS.

From: Gregory Bond <gnb at itga.com.au>
To: Nehal <nehalmistry at gmx.net>
Cc: FreeBSD-gnats-submit at FreeBSD.org
Subject: Re: kern/73148: cannot chmod mount point for read-only filesystem
Date: Tue, 26 Oct 2004 15:22:44 +1000

 Nehal wrote:
 
 >the chmod should only be denied for files/subdirectories
 >inside the mount point, not the mount point itself.
 >  
 >
 Um, this is never how Unix has operated.  After a mount(), the 
 underlying inode of the mount point is completely inacessible and hidden 
 by the root inode of the mounded FS until an unmount is done.  It's been 
 this way since V7 or earlier.  The FreeBSD man page for mount(2) hides 
 this a bit with some flowery language ("swept under the carpet"), but 
 consider the wording from Solaris 2.8 man page:
 
 DESCRIPTION
      The mount() function requests that a removable  file  system
      contained  on  the  block special file identified by spec be
      mounted on the directory identified by dir. The spec and dir
      arguments  are  pointers  to path names.  After a successful
      call to mount(), all references to the file dir refer to the
      root  directory on the mounted file system.
 
 In other words, this beahviour is as designed.