From: Shyam Prasad N <sprasad@microsoft.com>
Date: Sat, 30 Oct 2021 04:51:35 +0000
Subject: [PATCH] cifs: check reconnects for channels of active tcons too
Git-commit: 3663c9045f51a7ad635a0785adef07c21b79b560
References: bsc#1193629
Patch-mainline: v5.17-rc1

With the new multichannel logic, when a channel needs reconnection,
the tree connect and other channels can still be active.
This fix will handle cases of checking for channel reconnect,
when the tcon does not need reconnect.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/cifsglob.h |  2 ++
 fs/cifs/connect.c  | 34 +++++++++++++++++--
 fs/cifs/smb2pdu.c  | 82 +++++++++++++++++++++++++++++++++++++---------
 3 files changed, 99 insertions(+), 19 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index f84978b76bb6..cace0818d510 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -117,6 +117,7 @@ enum statusEnum {
 	CifsInSessSetup,
 	CifsNeedTcon,
 	CifsInTcon,
+	CifsNeedFilesInvalidate,
 	CifsInFilesInvalidate
 };
 
@@ -923,6 +924,7 @@ struct cifs_chan {
  */
 struct cifs_ses {
 	struct list_head smb_ses_list;
+	struct list_head rlist; /* reconnect list */
 	struct list_head tcon_list;
 	struct cifs_tcon *tcon_ipc;
 	struct mutex session_mutex;
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index accce1b351c6..804ffcde0391 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -335,6 +335,7 @@ static int __cifs_reconnect(struct TCP_Server_Info *server,
 			spin_unlock(&cifs_tcp_ses_lock);
 			cifs_swn_reset_server_dstaddr(server);
 			mutex_unlock(&server->srv_mutex);
+			mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
 		}
 	} while (server->tcpStatus == CifsNeedReconnect);
 
@@ -4404,9 +4405,22 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
 	char *tree;
 	struct dfs_info3_param ref = {0};
 
+	/* only send once per connect */
+	spin_lock(&cifs_tcp_ses_lock);
+	if (tcon->ses->status != CifsGood ||
+	    (tcon->tidStatus != CifsNew &&
+	    tcon->tidStatus != CifsNeedTcon)) {
+		spin_unlock(&cifs_tcp_ses_lock);
+		return 0;
+	}
+	tcon->tidStatus = CifsInTcon;
+	spin_unlock(&cifs_tcp_ses_lock);
+
 	tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
-	if (!tree)
-		return -ENOMEM;
+	if (!tree) {
+		rc = -ENOMEM;
+		goto out;
+	}
 
 	if (tcon->ipc) {
 		scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
@@ -4438,11 +4452,18 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
 	kfree(tree);
 	cifs_put_tcp_super(sb);
 
+	if (rc) {
+		spin_lock(&cifs_tcp_ses_lock);
+		tcon->tidStatus = CifsNeedTcon;
+		spin_unlock(&cifs_tcp_ses_lock);
+	}
+
 	return rc;
 }
 #else
 int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
 {
+	int rc;
 	const struct smb_version_operations *ops = tcon->ses->server->ops;
 
 	/* only send once per connect */
@@ -4456,6 +4477,13 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
 	tcon->tidStatus = CifsInTcon;
 	spin_unlock(&cifs_tcp_ses_lock);
 
-	return ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, nlsc);
+	rc = ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, nlsc);
+	if (rc) {
+		spin_lock(&cifs_tcp_ses_lock);
+		tcon->tidStatus = CifsNeedTcon;
+		spin_unlock(&cifs_tcp_ses_lock);
+	}
+
+	return rc;
 }
 #endif
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 625e3e9cb614..41b6dffc84c7 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -289,14 +289,18 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
 			rc = -EHOSTDOWN;
 			goto failed;
 		}
-	}
-
-	if (rc || !tcon->need_reconnect) {
+	} else {
 		mutex_unlock(&ses->session_mutex);
 		goto out;
 	}
+	mutex_unlock(&ses->session_mutex);
 
 skip_sess_setup:
+	mutex_lock(&ses->session_mutex);
+	if (!tcon->need_reconnect) {
+		mutex_unlock(&ses->session_mutex);
+		goto out;
+	}
 	cifs_mark_open_files_invalid(tcon);
 	if (tcon->use_persistent)
 		tcon->need_reopen_files = true;
@@ -3787,27 +3791,35 @@ void smb2_reconnect_server(struct work_struct *work)
 {
 	struct TCP_Server_Info *server = container_of(work,
 					struct TCP_Server_Info, reconnect.work);
-	struct cifs_ses *ses;
+	struct TCP_Server_Info *pserver;
+	struct cifs_ses *ses, *ses2;
 	struct cifs_tcon *tcon, *tcon2;
-	struct list_head tmp_list;
-	int tcon_exist = false;
+	struct list_head tmp_list, tmp_ses_list;
+	bool tcon_exist = false, ses_exist = false;
+	bool tcon_selected = false, ses_selected = false;
 	int rc;
-	int resched = false;
+	bool resched = false;
 
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
 
 	/* Prevent simultaneous reconnects that can corrupt tcon->rlist list */
-	mutex_lock(&server->reconnect_mutex);
+	mutex_lock(&pserver->reconnect_mutex);
 
 	INIT_LIST_HEAD(&tmp_list);
-	cifs_dbg(FYI, "Need negotiate, reconnecting tcons\n");
+	INIT_LIST_HEAD(&tmp_ses_list);
+	cifs_dbg(FYI, "Reconnecting tcons and channels\n");
 
 	spin_lock(&cifs_tcp_ses_lock);
-	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+
+		tcon_selected = ses_selected = false;
+
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 			if (tcon->need_reconnect || tcon->need_reopen_files) {
 				tcon->tc_count++;
 				list_add_tail(&tcon->rlist, &tmp_list);
-				tcon_exist = true;
+				tcon_selected = tcon_exist = true;
 			}
 		}
 		/*
@@ -3816,7 +3828,17 @@ void smb2_reconnect_server(struct work_struct *work)
 		 */
 		if (ses->tcon_ipc && ses->tcon_ipc->need_reconnect) {
 			list_add_tail(&ses->tcon_ipc->rlist, &tmp_list);
-			tcon_exist = true;
+			tcon_selected = tcon_exist = true;
+			ses->ses_count++;
+		}
+		/*
+		 * handle the case where channel needs to reconnect
+		 * binding session, but tcon is healthy (some other channel
+		 * is active)
+		 */
+		if (!tcon_selected && cifs_chan_needs_reconnect(ses, server)) {
+			list_add_tail(&ses->rlist, &tmp_ses_list);
+			ses_selected = ses_exist = true;
 			ses->ses_count++;
 		}
 	}
@@ -3824,7 +3846,7 @@ void smb2_reconnect_server(struct work_struct *work)
 	 * Get the reference to server struct to be sure that the last call of
 	 * cifs_put_tcon() in the loop below won't release the server pointer.
 	 */
-	if (tcon_exist)
+	if (tcon_exist || ses_exist)
 		server->srv_count++;
 
 	spin_unlock(&cifs_tcp_ses_lock);
@@ -3842,13 +3864,41 @@ void smb2_reconnect_server(struct work_struct *work)
 			cifs_put_tcon(tcon);
 	}
 
-	cifs_dbg(FYI, "Reconnecting tcons finished\n");
+	if (!ses_exist)
+		goto done;
+
+	/* allocate a dummy tcon struct used for reconnect */
+	tcon = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
+	if (!tcon) {
+		resched = true;
+		list_del_init(&ses->rlist);
+		cifs_put_smb_ses(ses);
+		goto done;
+	}
+
+	tcon->tidStatus = CifsGood;
+	tcon->retry = false;
+	tcon->need_reconnect = false;
+
+	/* now reconnect sessions for necessary channels */
+	list_for_each_entry_safe(ses, ses2, &tmp_ses_list, rlist) {
+		tcon->ses = ses;
+		rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon, server);
+		if (rc)
+			resched = true;
+		list_del_init(&ses->rlist);
+		cifs_put_smb_ses(ses);
+	}
+	kfree(tcon);
+
+done:
+	cifs_dbg(FYI, "Reconnecting tcons and channels finished\n");
 	if (resched)
 		queue_delayed_work(cifsiod_wq, &server->reconnect, 2 * HZ);
-	mutex_unlock(&server->reconnect_mutex);
+	mutex_unlock(&pserver->reconnect_mutex);
 
 	/* now we can safely release srv struct */
-	if (tcon_exist)
+	if (tcon_exist || ses_exist)
 		cifs_put_tcp_session(server, 1);
 }
 
-- 
2.36.1