[PATCH] cifs/smb3: directory sync should not return an error

Steve French smfrench at gmail.com
Thu May 10 21:56:16 UTC 2018

checking various Linux file systems - looks like most of those I
checked end up with the default "EINVAL" so basically not a very
useful call to check the return code on - safer to ignore.   If others
prefer, I don't mind sending the call over the wire and ignoring the
return code - but presumably some server is going to error unusually
if we pass it over the wire and expect particularly return codes (and
thus break apps that check for rc==EINVAL or rc==0).

On Thu, May 10, 2018 at 3:28 PM, Steve French <smfrench at gmail.com> wrote:
> It wasn't sent to Samba - the error was returned by the VFS before it
> comes to cifs.ko because we don't implement this call.    NFS
> (correctly presumably) implements the syscall by ignoring it
> (returning 0 - rather than the default which is an error), because
> once an entry in the directory is created it is in the namespace, and
> they are never cached on the client.
> On Thu, May 10, 2018 at 1:48 PM, Jeremy Allison <jra at samba.org> wrote:
>> On Thu, May 10, 2018 at 10:11:43AM -0700, Pavel Shilovsky via samba-technical wrote:
>>> 2018-05-10 9:04 GMT-07:00 Steve French via samba-technical
>>> <samba-technical at lists.samba.org>:
>>> > As with NFS, which ignores sync on directory handles,
>>> > fsync on a directory handle is a noop for CIFS/SMB3.
>>> > Do not return an error on it.  It breaks some database
>>> > apps otherwise.
>>> Reviewed-by: Pavel Shilovsky <pshilov at microsoft.com>
>> NAK on this patch. It's due to a specific Samba server
>> bug, which I've just fixed.
>> Look at the man page for fsync() on directory handles
>> - in SMB2+ as well this is a useful thing for an
>> application to do.
>> The broken Samba server returns NT_STATUS_ACCESS_DENIED
>> here. What you need to do is test the popular servers
>> (Windows, NetApp, EMC, Samba, OSX) and see which of
>> them are broken (not Windows obviously) and if so
>> what errors they return.
>> Best case scenario it's just Samba that was broken,
>> so check for the specific NT_STATUS_ACCESS_DENIED
>> error and ignore, otherwise return the error to
>> the caller - they *NEED* it :-).
>> Jeremy.
> --
> Thanks,
> Steve



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