Re: [PATCH ] Fix some problems with truncate and mtime semantics.

[Trond Myklebust <trond.myklebust@fys.uio.no>]

On Tue, 2005-11-15 at 13:00 +1100, NeilBrown wrote:
> Resubmitting this patch to fix truncate/mtime semantics.  
> 
> It is against 2.6.14-mm2 and is probably suitable for 2.6.15, but can
> be held over to 2.6.16 if you are feeling cautious.
> 
> NeilBrown
> 
> ### Comments for Changeset
> 
> SUS requires that when truncating a file to the size that it currently
> is:
>   truncate and ftruncate should NOT modify ctime or mtime
>   O_EXCL SHOULD modify ctime and mtime.
    ^^^^^ O_CREAT ;-)

> Currently mtime and ctime are always modified on most local
> filesystems (side effect of ->truncate) or never modified (on NFS).
> 
> With this patch:
>   ATTR_CTIME|ATTR_MTIME are sent with ATTR_SIZE precisely when 
>     an update of these times is required whether size changes or not 
>     (via a new argument to do_truncate).  This allows NFS to do
>     the right thing for O_EXCL.
                          ^^^^^

Cheers,
  Trond