Hi Sachin,
On 17 April 2017 at 05:37, Sachin Prabhu <sprabhu@xxxxxxxxxx> 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@xxxxxxxxxx>
> ---
> 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@xxxxxxxxx>
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