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kern/73146: cannot chmod mount point for read-only filesystem



The following reply was made to PR kern/73146; it has been noted by GNATS.

From: Ceri Davies <ceri_(_at_)_FreeBSD_(_dot_)_org>
To: FreeBSD Gnats Submit <freebsd-gnats-submit_(_at_)_FreeBSD_(_dot_)_org>
Cc:  
Subject: Re: kern/73146: cannot chmod mount point for read-only filesystem
Date: Tue, 26 Oct 2004 09:03:49 +0100

 Adding to audit trail, from kern/73148:
 
 From: Gregory Bond <gnb_(_at_)_itga_(_dot_)_com_(_dot_)_au>
 To: Nehal <nehalmistry_(_at_)_gmx_(_dot_)_net>
 Cc: FreeBSD-gnats-submit_(_at_)_FreeBSD_(_dot_)_org
 Subject: kern/73148: 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.