Merge tag 'v6.8-rc3-smb-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull smb client fixes from Steve French:
 "Five smb3 client fixes, mostly multichannel related:

   - four multichannel fixes including fix for channel allocation when
     multiple inactive channels, fix for unneeded race in channel
     deallocation, correct redundant channel scaling, and redundant
     multichannel disabling scenarios

   - add warning if max compound requests reached"

* tag 'v6.8-rc3-smb-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  smb: client: increase number of PDUs allowed in a compound request
  cifs: failure to add channel on iface should bump up weight
  cifs: do not search for channel if server is terminating
  cifs: avoid redundant calls to disable multichannel
  cifs: make sure that channel scaling is done only once

4 files changed, 31 insertions, 8 deletions

diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 16befff4cbb4..c86a72c9d9ec 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -87,7 +87,7 @@
 #define SMB_INTERFACE_POLL_INTERVAL	600
 
 /* maximum number of PDUs in one compound */
-#define MAX_COMPOUND 5
+#define MAX_COMPOUND 7
 
 /*
  * Default number of credits to keep available for SMB3.
@@ -1032,6 +1032,8 @@ struct cifs_chan {
 	__u8 signkey[SMB3_SIGN_KEY_SIZE];
 };
 
+#define CIFS_SES_FLAG_SCALE_CHANNELS (0x1)
+
 /*
  * Session structure.  One of these for each uid session with a particular host
  */
@@ -1064,6 +1066,7 @@ struct cifs_ses {
 	enum securityEnum sectype; /* what security flavor was specified? */
 	bool sign;		/* is signing required? */
 	bool domainAuto:1;
+	unsigned int flags;
 	__u16 session_flags;
 	__u8 smb3signingkey[SMB3_SIGN_KEY_SIZE];
 	__u8 smb3encryptionkey[SMB3_ENC_DEC_KEY_SIZE];
diff --git a/fs/smb/client/sess.c b/fs/smb/client/sess.c
index cde81042bebd..ed4bd88dd528 100644
--- a/fs/smb/client/sess.c
+++ b/fs/smb/client/sess.c
@@ -75,6 +75,10 @@ cifs_ses_get_chan_index(struct cifs_ses *ses,
 {
 	unsigned int i;
 
+	/* if the channel is waiting for termination */
+	if (server->terminate)
+		return CIFS_INVAL_CHAN_INDEX;
+
 	for (i = 0; i < ses->chan_count; i++) {
 		if (ses->chans[i].server == server)
 			return i;
@@ -269,6 +273,8 @@ int cifs_try_adding_channels(struct cifs_ses *ses)
 					 &iface->sockaddr,
 					 rc);
 				kref_put(&iface->refcount, release_iface);
+				/* failure to add chan should increase weight */
+				iface->weight_fulfilled++;
 				continue;
 			}
 
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 86f6f35b7f32..c58fa44dd6b0 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -178,6 +178,7 @@ cifs_chan_skip_or_disable(struct cifs_ses *ses,
 		}
 
 		ses->chans[chan_index].server = NULL;
+		server->terminate = true;
 		spin_unlock(&ses->chan_lock);
 
 		/*
@@ -188,7 +189,6 @@ cifs_chan_skip_or_disable(struct cifs_ses *ses,
 		 */
 		cifs_put_tcp_session(server, from_reconnect);
 
-		server->terminate = true;
 		cifs_signal_cifsd_for_reconnect(server, false);
 
 		/* mark primary server as needing reconnect */
@@ -399,6 +399,15 @@ skip_sess_setup:
 		goto out;
 	}
 
+	spin_lock(&ses->ses_lock);
+	if (ses->flags & CIFS_SES_FLAG_SCALE_CHANNELS) {
+		spin_unlock(&ses->ses_lock);
+		mutex_unlock(&ses->session_mutex);
+		goto skip_add_channels;
+	}
+	ses->flags |= CIFS_SES_FLAG_SCALE_CHANNELS;
+	spin_unlock(&ses->ses_lock);
+
 	if (!rc &&
 	    (server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) {
 		mutex_unlock(&ses->session_mutex);
@@ -410,7 +419,7 @@ skip_sess_setup:
 		rc = SMB3_request_interfaces(xid, tcon, false);
 		free_xid(xid);
 
-		if (rc == -EOPNOTSUPP) {
+		if (rc == -EOPNOTSUPP && ses->chan_count > 1) {
 			/*
 			 * some servers like Azure SMB server do not advertise
 			 * that multichannel has been disabled with server
@@ -428,17 +437,22 @@ skip_sess_setup:
 		if (ses->chan_max > ses->chan_count &&
 		    ses->iface_count &&
 		    !SERVER_IS_CHAN(server)) {
-			if (ses->chan_count == 1)
+			if (ses->chan_count == 1) {
 				cifs_server_dbg(VFS, "supports multichannel now\n");
+				queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
+						 (SMB_INTERFACE_POLL_INTERVAL * HZ));
+			}
 
 			cifs_try_adding_channels(ses);
-			queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
-					   (SMB_INTERFACE_POLL_INTERVAL * HZ));
 		}
 	} else {
 		mutex_unlock(&ses->session_mutex);
 	}
+
 skip_add_channels:
+	spin_lock(&ses->ses_lock);
+	ses->flags &= ~CIFS_SES_FLAG_SCALE_CHANNELS;
+	spin_unlock(&ses->ses_lock);
 
 	if (smb2_command != SMB2_INTERNAL_CMD)
 		mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
diff --git a/fs/smb/client/transport.c b/fs/smb/client/transport.c
index e00278fcfa4f..994d70193432 100644
--- a/fs/smb/client/transport.c
+++ b/fs/smb/client/transport.c
@@ -435,8 +435,8 @@ smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 	if (!(flags & CIFS_TRANSFORM_REQ))
 		return __smb_send_rqst(server, num_rqst, rqst);
 
-	if (num_rqst > MAX_COMPOUND - 1)
-		return -ENOMEM;
+	if (WARN_ON_ONCE(num_rqst > MAX_COMPOUND - 1))
+		return -EIO;
 
 	if (!server->ops->init_transform_rq) {
 		cifs_server_dbg(VFS, "Encryption requested but transform callback is missing\n");