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authorShyam Prasad N <sprasad@microsoft.com>2024-01-02 16:14:46 +0300
committerSteve French <stfrench@microsoft.com>2024-01-19 19:33:17 +0300
commitf591062bdbf4742b7f1622173017f19e927057b0 (patch)
treebf9bb7475e7d761d12cc670b86f3157027e2165f
parentce09f8d8a7130e6edfdd6fcad8eb277824d5de95 (diff)
downloadlinux-f591062bdbf4742b7f1622173017f19e927057b0.tar.xz
cifs: handle servers that still advertise multichannel after disabling
Some servers like Azure SMB servers always advertise multichannel capability in server capabilities list. Such servers return error STATUS_NOT_IMPLEMENTED for ioctl calls to query server interfaces, and expect clients to consider that as a sign that they do not support multichannel. We already handled this at mount time. Soon after the tree connect, we query server interfaces. And when server returned STATUS_NOT_IMPLEMENTED, we kept interface list as empty. When cifs_try_adding_channels gets called, it would not find any interfaces, so will not add channels. For the case where an active multichannel mount exists, and multichannel is disabled by such a server, this change will now allow the client to disable secondary channels on the mount. It will check the return status of query server interfaces call soon after a tree reconnect. If the return status is EOPNOTSUPP, then instead of the check to add more channels, we'll disable the secondary channels instead. For better code reuse, this change also moves the common code for disabling multichannel to a helper function. Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/smb/client/smb2ops.c8
-rw-r--r--fs/smb/client/smb2pdu.c107
2 files changed, 69 insertions, 46 deletions
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 01a5bd7e6a30..f080fac1b26e 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -614,7 +614,7 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
"multichannel not available\n"
"Empty network interface list returned by server %s\n",
ses->server->hostname);
- rc = -EINVAL;
+ rc = -EOPNOTSUPP;
goto out;
}
@@ -734,12 +734,6 @@ next_iface:
if ((bytes_left > 8) || p->Next)
cifs_dbg(VFS, "%s: incomplete interface info\n", __func__);
-
- if (!ses->iface_count) {
- rc = -EINVAL;
- goto out;
- }
-
out:
/*
* Go through the list again and put the inactive entries
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 88c60187593f..288199f0b987 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -156,6 +156,57 @@ out:
return;
}
+/* helper function for code reuse */
+static int
+cifs_chan_skip_or_disable(struct cifs_ses *ses,
+ struct TCP_Server_Info *server,
+ bool from_reconnect)
+{
+ struct TCP_Server_Info *pserver;
+ unsigned int chan_index;
+
+ if (SERVER_IS_CHAN(server)) {
+ cifs_dbg(VFS,
+ "server %s does not support multichannel anymore. Skip secondary channel\n",
+ ses->server->hostname);
+
+ spin_lock(&ses->chan_lock);
+ chan_index = cifs_ses_get_chan_index(ses, server);
+ if (chan_index == CIFS_INVAL_CHAN_INDEX) {
+ spin_unlock(&ses->chan_lock);
+ goto skip_terminate;
+ }
+
+ ses->chans[chan_index].server = NULL;
+ spin_unlock(&ses->chan_lock);
+
+ /*
+ * the above reference of server by channel
+ * needs to be dropped without holding chan_lock
+ * as cifs_put_tcp_session takes a higher lock
+ * i.e. cifs_tcp_ses_lock
+ */
+ cifs_put_tcp_session(server, from_reconnect);
+
+ server->terminate = true;
+ cifs_signal_cifsd_for_reconnect(server, false);
+
+ /* mark primary server as needing reconnect */
+ pserver = server->primary_server;
+ cifs_signal_cifsd_for_reconnect(pserver, false);
+skip_terminate:
+ mutex_unlock(&ses->session_mutex);
+ return -EHOSTDOWN;
+ }
+
+ cifs_server_dbg(VFS,
+ "server does not support multichannel anymore. Disable all other channels\n");
+ cifs_disable_secondary_channels(ses);
+
+
+ return 0;
+}
+
static int
smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
struct TCP_Server_Info *server, bool from_reconnect)
@@ -164,8 +215,6 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
struct nls_table *nls_codepage = NULL;
struct cifs_ses *ses;
int xid;
- struct TCP_Server_Info *pserver;
- unsigned int chan_index;
/*
* SMB2s NegProt, SessSetup, Logoff do not have tcon yet so
@@ -310,44 +359,11 @@ again:
*/
if (ses->chan_count > 1 &&
!(server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) {
- if (SERVER_IS_CHAN(server)) {
- cifs_dbg(VFS, "server %s does not support " \
- "multichannel anymore. skipping secondary channel\n",
- ses->server->hostname);
-
- spin_lock(&ses->chan_lock);
- chan_index = cifs_ses_get_chan_index(ses, server);
- if (chan_index == CIFS_INVAL_CHAN_INDEX) {
- spin_unlock(&ses->chan_lock);
- goto skip_terminate;
- }
-
- ses->chans[chan_index].server = NULL;
- spin_unlock(&ses->chan_lock);
-
- /*
- * the above reference of server by channel
- * needs to be dropped without holding chan_lock
- * as cifs_put_tcp_session takes a higher lock
- * i.e. cifs_tcp_ses_lock
- */
- cifs_put_tcp_session(server, from_reconnect);
-
- server->terminate = true;
- cifs_signal_cifsd_for_reconnect(server, false);
-
- /* mark primary server as needing reconnect */
- pserver = server->primary_server;
- cifs_signal_cifsd_for_reconnect(pserver, false);
-
-skip_terminate:
+ rc = cifs_chan_skip_or_disable(ses, server,
+ from_reconnect);
+ if (rc) {
mutex_unlock(&ses->session_mutex);
- rc = -EHOSTDOWN;
goto out;
- } else {
- cifs_server_dbg(VFS, "does not support " \
- "multichannel anymore. disabling all other channels\n");
- cifs_disable_secondary_channels(ses);
}
}
@@ -395,11 +411,23 @@ skip_sess_setup:
rc = SMB3_request_interfaces(xid, tcon, false);
free_xid(xid);
- if (rc)
+ if (rc == -EOPNOTSUPP) {
+ /*
+ * some servers like Azure SMB server do not advertise
+ * that multichannel has been disabled with server
+ * capabilities, rather return STATUS_NOT_IMPLEMENTED.
+ * treat this as server not supporting multichannel
+ */
+
+ rc = cifs_chan_skip_or_disable(ses, server,
+ from_reconnect);
+ goto skip_add_channels;
+ } else if (rc)
cifs_dbg(FYI, "%s: failed to query server interfaces: %d\n",
__func__, rc);
if (ses->chan_max > ses->chan_count &&
+ ses->iface_count &&
!SERVER_IS_CHAN(server)) {
if (ses->chan_count == 1)
cifs_server_dbg(VFS, "supports multichannel now\n");
@@ -411,6 +439,7 @@ skip_sess_setup:
} else {
mutex_unlock(&ses->session_mutex);
}
+skip_add_channels:
if (smb2_command != SMB2_INTERNAL_CMD)
mod_delayed_work(cifsiod_wq, &server->reconnect, 0);