Subject: Re: which ioctls matter across filesystems
From: Robert Love <rml@novell.com>
To: Steve French <smfrench@austin.rr.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>, linux-kernel@vger.kernel.org
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Date: Fri, 29 Apr 2005 16:50:35 -0400
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On Fri, 2005-04-29 at 15:47 -0500, Steve French wrote:

> I am not sure - but it is obviously required that inotify can pass over 
> CIFS (and probably NFS) since change notification is hardest for the 
> user to figure out when they are on a network.   I am not sure how the 
> filesystem can detect that a new watch is added to one of its inodes - 
> it looks like you added an ioctl to a device but I am still reading 
> through your latest patch.   I was looking for something like an inode 
> operation that cifs could hook so the fs could be told when a new watch 
> was added or one was changed.   In any case I need to construct 
> functions somewhat similar to what is in fs/cifs/fcntl.c and need to 
> finish/modify CIFSSMBNotify in fs/cifs/cifssmb.c to map the inotify 
> flags to the flags available in the CIFS network protocol specifications.
> The existing network protocol support for ChangeNotify is more 
> straightforward than you might think and the filter flags & actions that 
> I have at my disposal for implementing notify across the network are in 
> fs/cifs/cifspdu.h already (search for FILE_ACTION_   and FILE_NOTIFY_ if 
> you are curious) but obviously they are similar to what the other Samba 
> team guys have already told you.

So a client adds a watch and the server needs to then physically add the
inotify watch?

If you have a user-space, user-space could just add an inotify watch.

But I guess you live entirely in kernel-space?  Couldn't we just export
our "add watch" interface to you?

	Robert Love


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