Fwd: [PATCH] cifs: Do not send echoes before Negotiate is complete

From: Steve French <smfrench-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: "linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Fwd: [PATCH] cifs: Do not send echoes before Negotiate is complete
Date: Sun, 16 Apr 2017 23:28:00 -0500	[thread overview]
Message-ID: <CAH2r5mvQpmRJVX5KhrtD4A=4yfoe9MrB+X+ckrTCHqWrShVFHA@mail.gmail.com> (raw)
In-Reply-To: <CAH2r5mvMHLHLLK3-dT=s_mbuKPWfLF8PWtz-VkwwWzdyez1uLQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

I fixed the checkpatch error (missing tab in Sachin's patch) and
merged into cifs-2.6.git

thx

On Sun, Apr 16, 2017 at 5:59 PM, Jonathan Liu <net147-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> Hi Sachin,
>
> On 17 April 2017 at 05:37, Sachin Prabhu <sprabhu-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> > commit 4fcd1813e640 ("Fix reconnect to not defer smb3 session reconnect
> > long after socket reconnect") added support for Negotiate requests to
> > be initiated by echo calls.
> >
> > To avoid delays in calling echo after a reconnect, I added the patch
> > introduced by the commit b8c600120fc8 ("Call echo service immediately
> > after socket reconnect").
> >
> > This has however caused a regression with cifs shares which do not have
> > support for echo calls to trigger Negotiate requests. On connections
> > which need to call Negotiation, the echo calls trigger an error which
> > triggers a reconnect which in turn triggers another echo call. This
> > results in a loop which is only broken when an operation is performed on
> > the cifs share. For an idle share, it can DOS a server.
> >
> > The patch uses the smb_operation can_echo() for cifs so that it is
> > called only if connection has been already been setup.
> >
> > kernel bz: 194531
> >
> > Signed-off-by: Sachin Prabhu <sprabhu-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > ---
> >  fs/cifs/smb1ops.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> >
> > diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
> > index cc93ba4..60a1979 100644
> > --- a/fs/cifs/smb1ops.c
> > +++ b/fs/cifs/smb1ops.c
> > @@ -1015,6 +1015,15 @@ cifs_dir_needs_close(struct cifsFileInfo *cfile)
> >         return !cfile->srch_inf.endOfSearch && !cfile->invalidHandle;
> >  }
> >
> > +static bool
> > +cifs_can_echo(struct TCP_Server_Info *server)
> > +{
> > +       if (server->tcpStatus == CifsGood)
> > +               return true;
> > +
> > +       return false;
> > +}
> > +
> >  struct smb_version_operations smb1_operations = {
> >         .send_cancel = send_nt_cancel,
> >         .compare_fids = cifs_compare_fids,
> > @@ -1049,6 +1058,7 @@ struct smb_version_operations smb1_operations = {
> >         .get_dfs_refer = CIFSGetDFSRefer,
> >         .qfs_tcon = cifs_qfs_tcon,
> >         .is_path_accessible = cifs_is_path_accessible,
> > +       .can_echo = cifs_can_echo,
> >         .query_path_info = cifs_query_path_info,
> >         .query_file_info = cifs_query_file_info,
> >         .get_srv_inum = cifs_get_srv_inum,
> > --
> > 2.9.3
> >
>
> This fixes the issue for me.
>
> Tested-by: Jonathan Liu <net147-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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-- 
Thanks,

Steve


-- 
Thanks,

Steve