[PATCH 11/14] cifs: handle when server starts supporting multichannel

nspmangalore
2023-10-30T11:00:58Z

From: Shyam Prasad N <sprasad@microsoft.com>

When the user mounts with multichannel option, but the
server does not support it, there can be a time in future
where it can be supported.

With this change, such a case is handled.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
---
fs/smb/client/cifsproto.h | 4 ++++
fs/smb/client/connect.c | 6 +++++-
fs/smb/client/smb2pdu.c | 31 ++++++++++++++++++++++++++++---
3 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h
index 65c84b3d1a65..5a4c1f1e0d91 100644
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -132,6 +132,10 @@ extern int SendReceiveBlockingLock(const unsigned int xid,
struct smb_hdr *in_buf,
struct smb_hdr *out_buf,
int *bytes_returned);
+
+void
+smb2_query_server_interfaces(struct work_struct *work);
+
void
cifs_signal_cifsd_for_reconnect(struct TCP_Server_Info *server,
bool all_channels);
diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index e71aa33bf026..149cde77500e 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -116,7 +116,8 @@ static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
return rc;
}

-static void smb2_query_server_interfaces(struct work_struct *work)
+void
+smb2_query_server_interfaces(struct work_struct *work)
{
int rc;
int xid;
@@ -134,6 +135,9 @@ static void smb2_query_server_interfaces(struct work_struct *work)
if (rc) {
cifs_dbg(FYI, "%s: failed to query server interfaces: %d\n",
__func__, rc);
+
+ if (rc == -EOPNOTSUPP)
+ return;
}

queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index b7665155f4e2..2617437a4627 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -163,6 +163,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
int rc = 0;
struct nls_table *nls_codepage = NULL;
struct cifs_ses *ses;
+ int xid;

/*
* SMB2s NegProt, SessSetup, Logoff do not have tcon yet so
@@ -307,17 +308,41 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
tcon->need_reopen_files = true;

rc = cifs_tree_connect(0, tcon, nls_codepage);
- mutex_unlock(&ses->session_mutex);

cifs_dbg(FYI, "reconnect tcon rc = %d\n", rc);
if (rc) {
/* If sess reconnected but tcon didn't, something strange ... */
+ mutex_unlock(&ses->session_mutex);
cifs_dbg(VFS, "reconnect tcon failed rc = %d\n", rc);
goto out;
}

- if (smb2_command != SMB2_INTERNAL_CMD)
- mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
+ if (!rc &&
+ (server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) {
+ mutex_unlock(&ses->session_mutex);
+
+ /*
+ * query server network interfaces, in case they change
+ */
+ xid = get_xid();
+ rc = SMB3_request_interfaces(xid, tcon, false);
+ free_xid(xid);
+
+ if (rc)
+ cifs_dbg(FYI, "%s: failed to query server interfaces: %d\n",
+ __func__, rc);
+
+ if (ses->chan_max > ses->chan_count &&
+ !SERVER_IS_CHAN(server)) {
+ if (ses->chan_count == 1)
+ cifs_dbg(VFS, "server %s supports multichannel now\n",
+ ses->server->hostname);
+
+ cifs_try_adding_channels(tcon->cifs_sb, ses);
+ }
+ } else {
+ mutex_unlock(&ses->session_mutex);
+ }

atomic_inc(&tconInfoReconnectCount);
out:
--
2.34.1