linux-kernel - [PATCH v2 5.4 2/2] cifs: handle empty list of targets in cifs

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Message-ID: <20230607203333.26669-3-risbhat@amazon.com>
Date:   Wed, 7 Jun 2023 20:33:33 +0000
From:   Rishabh Bhatnagar <risbhat@...zon.com>
To:     <gregkh@...uxfoundation.org>
CC:     <sfrench@...zon.com>, <stable@...r.kernel.org>,
        <linux-cifs@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Paulo Alcantara <pc@....nz>, Aurelien Aptel <aaptel@...e.com>,
        Steve French <stfrench@...rosoft.com>,
        Rishabh Bhatnagar <risbhat@...zon.com>
Subject: [PATCH v2 5.4 2/2] cifs: handle empty list of targets in cifs_reconnect()

From: Paulo Alcantara <pc@....nz>

commit a52930353eaf443489a350a135c5525a4acbbf56 upstream.

In case there were no cached DFS referrals in
reconn_setup_dfs_targets(), set cifs_sb to NULL prior to calling
reconn_set_next_dfs_target() so it would not try to access an empty
tgt_list.

Signed-off-by: Paulo Alcantara (SUSE) <pc@....nz>
Reviewed-by: Aurelien Aptel <aaptel@...e.com>
Signed-off-by: Steve French <stfrench@...rosoft.com>
Signed-off-by: Rishabh Bhatnagar <risbhat@...zon.com>
---
 fs/cifs/connect.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index b5cd3dc479ce..d8d9d9061544 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -513,11 +513,13 @@ cifs_reconnect(struct TCP_Server_Info *server)
 		sb = NULL;
 	} else {
 		cifs_sb = CIFS_SB(sb);
-
 		rc = reconn_setup_dfs_targets(cifs_sb, &tgt_list);
-		if (rc && (rc != -EOPNOTSUPP)) {
-			cifs_server_dbg(VFS, "%s: no target servers for DFS failover\n",
-				 __func__);
+		if (rc) {
+			cifs_sb = NULL;
+			if (rc != -EOPNOTSUPP) {
+				cifs_server_dbg(VFS, "%s: no target servers for DFS failover\n",
+						__func__);
+			}
 		} else {
 			server->nr_targets = dfs_cache_get_nr_tgts(&tgt_list);
 		}
-- 
2.39.2