4 fixes to cifs client, 1 for stable

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Merge tag '5.18-rc1-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs client fixes from Steve French:

 - reconnect fixes: one for DFS and one to avoid a reconnect race

 - small change to deal with upcoming behavior change of list iterators

* tag '5.18-rc1-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: update internal module number
  cifs: force new session setup and tcon for dfs
  cifs: remove check of list iterator against head past the loop body
  cifs: fix potential race with cifsd thread

fs/cifs/cifsfs.h

@@ -153,5 +153,5 @@ extern const struct export_operations cifs_export_ops;
 #endif /* CONFIG_CIFS_NFSD_EXPORT */
 
 #define SMB3_PRODUCT_BUILD 35
-#define CIFS_VERSION   "2.35"
+#define CIFS_VERSION   "2.36"
 #endif				/* _CIFSFS_H */

fs/cifs/connect.c

@@ -453,9 +453,7 @@ static int reconnect_target_unlocked(struct TCP_Server_Info *server, struct dfs_
 	return rc;
 }
 
-static int
-reconnect_dfs_server(struct TCP_Server_Info *server,
-		     bool mark_smb_session)
+static int reconnect_dfs_server(struct TCP_Server_Info *server)
 {
 	int rc = 0;
 	const char *refpath = server->current_fullpath + 1;
@@ -479,7 +477,12 @@ reconnect_dfs_server(struct TCP_Server_Info *server,
 	if (!cifs_tcp_ses_needs_reconnect(server, num_targets))
 		return 0;
 
-	cifs_mark_tcp_ses_conns_for_reconnect(server, mark_smb_session);
+	/*
+	 * Unconditionally mark all sessions & tcons for reconnect as we might be connecting to a
+	 * different server or share during failover.  It could be improved by adding some logic to
+	 * only do that in case it connects to a different server or share, though.
+	 */
+	cifs_mark_tcp_ses_conns_for_reconnect(server, true);
 
 	cifs_abort_connection(server);
 
@@ -537,7 +540,7 @@ int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
 	}
 	spin_unlock(&cifs_tcp_ses_lock);
 
-	return reconnect_dfs_server(server, mark_smb_session);
+	return reconnect_dfs_server(server);
 }
 #else
 int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
@@ -4465,7 +4468,7 @@ static int tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *tco
 	 */
 	if (rc && server->current_fullpath != server->origin_fullpath) {
 		server->current_fullpath = server->origin_fullpath;
-		cifs_reconnect(tcon->ses->server, true);
+		cifs_signal_cifsd_for_reconnect(server, true);
 	}
 
 	dfs_cache_free_tgts(tl);

fs/cifs/netmisc.c

@@ -896,7 +896,7 @@ map_and_check_smb_error(struct mid_q_entry *mid, bool logErr)
 		if (class == ERRSRV && code == ERRbaduid) {
 			cifs_dbg(FYI, "Server returned 0x%x, reconnecting session...\n",
 				code);
-			cifs_reconnect(mid->server, false);
+			cifs_signal_cifsd_for_reconnect(mid->server, false);
 		}
 	}
 

fs/cifs/smb2misc.c

@@ -150,16 +150,18 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *srvr)
 		struct smb2_transform_hdr *thdr =
 			(struct smb2_transform_hdr *)buf;
 		struct cifs_ses *ses = NULL;
+		struct cifs_ses *iter;
 
 		/* decrypt frame now that it is completely read in */
 		spin_lock(&cifs_tcp_ses_lock);
-		list_for_each_entry(ses, &srvr->smb_ses_list, smb_ses_list) {
-			if (ses->Suid == le64_to_cpu(thdr->SessionId))
+		list_for_each_entry(iter, &srvr->smb_ses_list, smb_ses_list) {
+			if (iter->Suid == le64_to_cpu(thdr->SessionId)) {
+				ses = iter;
 				break;
+			}
 		}
 		spin_unlock(&cifs_tcp_ses_lock);
-		if (list_entry_is_head(ses, &srvr->smb_ses_list,
-				       smb_ses_list)) {
+		if (!ses) {
 			cifs_dbg(VFS, "no decryption - session id not found\n");
 			return 1;
 		}