> The open2() API returns the updated attributes of the file.  So, if they changed
> (for example because of a truncate) then we need a getattrs() to return the new
> attributes.  The actual truncation is taken care of by the actual open call
> (GPFSFSAL_open() -> fsal_internal_handle2fd() ->
> OPENHANDLE_OPEN_BY_HANDLE)
>
> If a FSAL had an extended open call that returned attributes directly, then it
> wouldn't need a separate getattrs().

It looks like MDCACHE invalidates the attributes on open2 by handle with truncate though...

Frank

> Daniel
>
> On 08/07/2018 01:36 PM, Tuan Viet Nguyen wrote:
> > Thanks Daniel,
> >
> > I've just tested it again and confirm that it works, sorry for the
> > noise. But why in GPFS for example we getattrs in case of truncated
> > instead of setting attrs with size and new ctime? (open_by_handle)
> >
> > Thank you
> >
> > On Tue, Aug 7, 2018 at 7:22 PM, Daniel Gryniewicz <dang@redhat.com
> > <mailto:dang@redhat.com>> wrote:
> >
> >     On 08/07/2018 01:03 PM, ntvietvn@gmail.com
> >     <mailto:ntvietvn@gmail.com> wrote:
> >
> >         Hello,
> >
> >         Can anyone explain how O_TRUNC is handled (open2)? When I try to
> >         open an existing file with this flag, the FSAL_O_TRUNC in
> >         openflags is not enabled in my FSAL open2 fct.
> >         While capturing with tcpdump, the NFS client actually sends a
> >         OPEN then SETATTR with size = 0 but not ctime.
> >
> >         By looking at an example in open_by_handle, if IIUC if the flag
> >         O_TRUNC is there, we refresh the attrs by calling getattrs to
> >         attrs_out, I do not understand that, why it does that instead of
> >         calling setattrs ?
> >
> >
> >     It should work (and, in fact, passes tests, so it does...)  Here's
> >     what happens:
> >
> >     In nfs4_op_open() It checks the attributes to set for ATTR_SIZE, and
> >     if that's zero, it sets FSAL_O_TRUNC in openflags.  This is passed to:
> >
> >     fsal_open2(), which does the same check, and again sets FSAL_O_TRUNC
> >     in openflags.  If there's no name (this is an open-by-handle),
> >     openflags is passed to obj_ops->open2(); if there's a name, it's
> >     passed to open2_by_name(), which passes it to obj_ops->open().
> >     Either way, it gets to:
> >
> >     mdcache_open2() which calls mdc_open2_by_name() (if there's a name)
> >     which calls obj_ops->open2(), or directly calls obj_ops->open2(); in
> >     either case, that's calling into the FSAL with FSAL_O_TRUNC set.
> >     Once that returns, if that flag is set, MDCACHE invalidates the
> >     cached attributes for that handle.
> >
> >     So, it looks like it should be working properly.
> >
> >     Daniel
> >
> >     _______________________________________________
> >     Devel mailing list -- devel@lists.nfs-ganesha.org
> >     <mailto:devel@lists.nfs-ganesha.org>
> >     To unsubscribe send an email to devel-leave@lists.nfs-ganesha.org
> >     <mailto:devel-leave@lists.nfs-ganesha.org>
> >
> >
> _______________________________________________

> Devel mailing list -- devel@lists.nfs-ganesha.org To unsubscribe send an email to
> devel-leave@lists.nfs-ganesha.org