cifs: On cifs_reconnect, resolve the hostname again.

On cifs_reconnect, make sure that DNS resolution happens again.
It could be the cause of connection to go dead in the first place.

This also contains the fix for a build issue identified by Intel bot.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: <stable@vger.kernel.org> # 5.11+
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index fe03cbd..bf52e93 100644 (file)
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -18,6 +18,7 @@ config CIFS
        select CRYPTO_AES
        select CRYPTO_LIB_DES
        select KEYS
+       select DNS_RESOLVER
        help
          This is the client VFS module for the SMB3 family of NAS protocols,
          (including support for the most recent, most secure dialect SMB3.1.1)
@@ -112,7 +113,6 @@ config CIFS_WEAK_PW_HASH
 config CIFS_UPCALL
        bool "Kerberos/SPNEGO advanced session setup"
        depends on CIFS
-       select DNS_RESOLVER
        help
          Enables an upcall mechanism for CIFS which accesses userspace helper
          utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
@@ -179,7 +179,6 @@ config CIFS_DEBUG_DUMP_KEYS
 config CIFS_DFS_UPCALL
        bool "DFS feature support"
        depends on CIFS
-       select DNS_RESOLVER
        help
          Distributed File System (DFS) support is used to access shares
          transparently in an enterprise name space, even if the share

diff --git a/fs/cifs/Makefile b/fs/cifs/Makefile
index 5213b20..3ee3b7d 100644 (file)
--- a/fs/cifs/Makefile
+++ b/fs/cifs/Makefile
@@ -10,13 +10,14 @@ cifs-y := trace.o cifsfs.o cifssmb.o cifs_debug.o connect.o dir.o file.o \
          cifs_unicode.o nterr.o cifsencrypt.o \
          readdir.o ioctl.o sess.o export.o smb1ops.o unc.o winucase.o \
          smb2ops.o smb2maperror.o smb2transport.o \
-         smb2misc.o smb2pdu.o smb2inode.o smb2file.o cifsacl.o fs_context.o
+         smb2misc.o smb2pdu.o smb2inode.o smb2file.o cifsacl.o fs_context.o \
+         dns_resolve.o
 
 cifs-$(CONFIG_CIFS_XATTR) += xattr.o
 
 cifs-$(CONFIG_CIFS_UPCALL) += cifs_spnego.o
 
-cifs-$(CONFIG_CIFS_DFS_UPCALL) += dns_resolve.o cifs_dfs_ref.o dfs_cache.o
+cifs-$(CONFIG_CIFS_DFS_UPCALL) += cifs_dfs_ref.o dfs_cache.o
 
 cifs-$(CONFIG_CIFS_SWN_UPCALL) += netlink.o cifs_swn.o
 

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index eec8a20..24668eb 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -87,7 +87,6 @@ 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_from_hostname(struct TCP_Server_Info *server)
 {
        int rc;
@@ -124,6 +123,7 @@ static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
        return !rc ? -1 : 0;
 }
 
+#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,
@@ -321,14 +321,29 @@ cifs_reconnect(struct TCP_Server_Info *server)
 #endif
 
 #ifdef CONFIG_CIFS_DFS_UPCALL
+               if (cifs_sb && cifs_sb->origin_fullpath)
                        /*
                         * Set up next DFS target server (if any) for reconnect. If DFS
                         * feature is disabled, then we will retry last server we
                         * connected to before.
                         */
                        reconn_set_next_dfs_target(server, cifs_sb, &tgt_list, &tgt_it);
+               else {
+#endif
+                       /*
+                        * Resolve the hostname again to make sure that IP address is up-to-date.
+                        */
+                       rc = reconn_set_ipaddr_from_hostname(server);
+                       if (rc) {
+                               cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
+                                               __func__, rc);
+                       }
+
+#ifdef CONFIG_CIFS_DFS_UPCALL
+               }
 #endif
 
+
 #ifdef CONFIG_CIFS_SWN_UPCALL
                }
 #endif