[v4,09/11] cifs: Simplify reconnect code when dfs upcall is enabled

Some witness notifications, like client move, tell the client to
reconnect to a specific IP address. In this situation the DFS failover
code path has to be skipped so clean up as much as possible the
cifs_reconnect() code.

Signed-off-by: Samuel Cabrero <scabrero@suse.de>
---
 fs/cifs/connect.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

tentatively merged into cifs-2.6.git for-next, let me know if any
changes need to be made to it.

On Mon, Nov 30, 2020 at 12:05 PM Samuel Cabrero <scabrero@suse.de> wrote:
>
> Some witness notifications, like client move, tell the client to
> reconnect to a specific IP address. In this situation the DFS failover
> code path has to be skipped so clean up as much as possible the
> cifs_reconnect() code.
>
> Signed-off-by: Samuel Cabrero <scabrero@suse.de>
> ---
>  fs/cifs/connect.c | 21 ++++++++-------------
>  1 file changed, 8 insertions(+), 13 deletions(-)
>
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index a298518bebb2..3af88711643b 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -296,7 +296,7 @@ static void cifs_prune_tlinks(struct work_struct *work);
>   * This should be called with server->srv_mutex held.
>   */
>  #ifdef CONFIG_CIFS_DFS_UPCALL
> -static int reconn_set_ipaddr(struct TCP_Server_Info *server)
> +static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
>  {
>         int rc;
>         int len;
> @@ -331,14 +331,7 @@ static int reconn_set_ipaddr(struct TCP_Server_Info *server)
>
>         return !rc ? -1 : 0;
>  }
> -#else
> -static inline int reconn_set_ipaddr(struct TCP_Server_Info *server)
> -{
> -       return 0;
> -}
> -#endif
>
> -#ifdef CONFIG_CIFS_DFS_UPCALL
>  /* These functions must be called with server->srv_mutex held */
>  static void reconn_set_next_dfs_target(struct TCP_Server_Info *server,
>                                        struct cifs_sb_info *cifs_sb,
> @@ -346,6 +339,7 @@ static void reconn_set_next_dfs_target(struct TCP_Server_Info *server,
>                                        struct dfs_cache_tgt_iterator **tgt_it)
>  {
>         const char *name;
> +       int rc;
>
>         if (!cifs_sb || !cifs_sb->origin_fullpath)
>                 return;
> @@ -370,6 +364,12 @@ static void reconn_set_next_dfs_target(struct TCP_Server_Info *server,
>                          "%s: failed to extract hostname from target: %ld\n",
>                          __func__, PTR_ERR(server->hostname));
>         }
> +
> +       rc = reconn_set_ipaddr_from_hostname(server);
> +       if (rc) {
> +               cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
> +                        __func__, rc);
> +       }
>  }
>
>  static inline int reconn_setup_dfs_targets(struct cifs_sb_info *cifs_sb,
> @@ -528,11 +528,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
>                  */
>                 reconn_set_next_dfs_target(server, cifs_sb, &tgt_list, &tgt_it);
>  #endif
> -               rc = reconn_set_ipaddr(server);
> -               if (rc) {
> -                       cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
> -                                __func__, rc);
> -               }
>
>                 if (cifs_rdma_enabled(server))
>                         rc = smbd_reconnect(server);
> --
> 2.29.2
>