cifs: fix check of tcon dfs in smb1

For SMB1, the DFS flag should be checked against tcon->Flags rather
than tcon->share_flags.  While at it, add an is_tcon_dfs() helper to
check for DFS capability in a more generic way.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index b296964..b565d83 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -2031,4 +2031,19 @@ static inline bool is_smb1_server(struct TCP_Server_Info *server)
        return strcmp(server->vals->version_string, SMB1_VERSION_STRING) == 0;
 }
 
+static inline bool is_tcon_dfs(struct cifs_tcon *tcon)
+{
+       /*
+        * For SMB1, see MS-CIFS 2.4.55 SMB_COM_TREE_CONNECT_ANDX (0x75) and MS-CIFS 3.3.4.4 DFS
+        * Subsystem Notifies That a Share Is a DFS Share.
+        *
+        * For SMB2+, see MS-SMB2 2.2.10 SMB2 TREE_CONNECT Response and MS-SMB2 3.3.4.14 Server
+        * Application Updates a Share.
+        */
+       if (!tcon || !tcon->ses || !tcon->ses->server)
+               return false;
+       return is_smb1_server(tcon->ses->server) ? tcon->Flags & SMB_SHARE_IS_IN_DFS :
+               tcon->share_flags & (SHI1005_FLAGS_DFS | SHI1005_FLAGS_DFS_ROOT);
+}
+
 #endif /* _CIFS_GLOB_H */

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a275ee3..392c44d 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -4909,7 +4909,7 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
                if (!tcon)
                        continue;
                /* Make sure that requests go through new root servers */
-               if (tcon->share_flags & (SHI1005_FLAGS_DFS | SHI1005_FLAGS_DFS_ROOT)) {
+               if (is_tcon_dfs(tcon)) {
                        put_root_ses(root_ses);
                        set_root_ses(cifs_sb, ses, &root_ses);
                }