From: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Date: Thu, 3 Oct 2013 10:44:45 +0000 (-0500)
Subject: cifs: Avoid umount hangs with smb2 when server is unresponsive
X-Git-Tag: Ubuntu-snapdragon-4.4.0-1029.32~9959^2~3
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=eb4c7df6c20b407ecbf1a985edc33d967371c2e8;p=mirror_ubuntu-zesty-kernel.git

cifs: Avoid umount hangs with smb2 when server is unresponsive

Do not send SMB2 Logoff command when reconnecting, the way smb1
code base works.

Also, no need to wait for a credit for an echo command when one is already
in flight.

Without these changes, umount command hangs if the server is unresponsive
e.g. hibernating.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@us.ibm.com>
---

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index eba0efde66d7..edccb5252462 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -687,6 +687,10 @@ SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
 	else
 		return -EIO;
 
+	/* no need to send SMB logoff if uid already closed due to reconnect */
+	if (ses->need_reconnect)
+		goto smb2_session_already_dead;
+
 	rc = small_smb2_init(SMB2_LOGOFF, NULL, (void **) &req);
 	if (rc)
 		return rc;
@@ -701,6 +705,8 @@ SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
 	 * No tcon so can't do
 	 * cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
 	 */
+
+smb2_session_already_dead:
 	return rc;
 }
 
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 6fdcb1b4a106..800b938e4061 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -410,8 +410,13 @@ static int
 wait_for_free_request(struct TCP_Server_Info *server, const int timeout,
 		      const int optype)
 {
-	return wait_for_free_credits(server, timeout,
-				server->ops->get_credits_field(server, optype));
+	int *val;
+
+	val = server->ops->get_credits_field(server, optype);
+	/* Since an echo is already inflight, no need to wait to send another */
+	if (*val <= 0 && optype == CIFS_ECHO_OP)
+		return -EAGAIN;
+	return wait_for_free_credits(server, timeout, val);
 }
 
 static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,