[PATCH 02/18] xstat: Add a pair of system calls to make extended file stats available [ver #6]

[John Stoffel]

>>>>> "Jeremy" == Jeremy Allison <jra at samba.org> writes:

Jeremy> On Thu, Jul 22, 2010 at 12:58:50PM -0400, Trond Myklebust wrote:
>> 
>> That would make it impossible to export the filesystem with NFSv2 and
>> v3. They do rely on ctime checking for certain operations (e.g. deciding
>> when to invalidate access and acl caches). NFSv4 needs this too if the
>> filesystem has no dedicated change attribute.
>> 
>> Still, I suppose the market for exporting the same filesystem with both
>> NFS and Samba is limited...

Jeremy> Ask NetApp about that :-). They have built a rather large
Jeremy> business on just that fact :-).

And it does work, as long as you also go with either unix or windows
semantics for the security and permissions bits.  If you try to use
the mixed-mode, you're in for a world of hurt.

Oh yeah, Netapp still uses dump/restore for it's backups.  :]  Though
whether it's still dependent on the optimization of ctime being used
to know whether to just dump the inode only or not, I can't say.

John