Re: [RFC][PATCH 0/12]ext4: online defrag (ver 0.95)

[Theodore Tso <tytso@mit.edu>]

On Wed, Oct 01, 2008 at 02:45:45PM -0400, Christoph Hellwig wrote:
> On Tue, Sep 30, 2008 at 05:40:54PM -0700, Andreas Dilger wrote:
> > Instead of implementing an EXT4_IOC_FIEMAP_INO ioctl, what we had implemented
> > is an EXT4_IOC_WRAPPER, which takes as arguments the inode number and the
> > ioctl command + original ioctl data.  This allows inode ioctls to be called
> > against the filesystem root for arbitrary inodes, and doesn't require new
> > implementation for each ioctl:
> 
> Or just provide more generic open by handle functionality.  Shouldn't be
> too much of a problem to do it in the VFS by reusing the exportfs code.
> 

A while back I had implemented an "open by inode" patch for a friend
who needed it for their startup.  I never posted it because (a) even
though it was only optionally enabled via a mount option, if you allow
non-root users to access it, it blows a whole through traditional unix
permissions semantics (i.e., a mode 700 directory no longer protects
files underneath that directory), and (b) I was sure that Al Viro
would consider the hacks that I needed to make it work to be far too
ugly to live.   :-)

						- Ted