6.6-stable review patch. If anyone has any objections, please let me know.
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From: Shyam Prasad N sprasad@microsoft.com
[ Upstream commit f591062bdbf4742b7f1622173017f19e927057b0 ]
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 Stable-dep-of: 78e727e58e54 ("cifs: update iface_last_update on each query-and-update") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/smb/client/smb2ops.c | 8 +-- fs/smb/client/smb2pdu.c | 107 +++++++++++++++++++++++++--------------- 2 files changed, 69 insertions(+), 46 deletions(-)
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index 0604696f59c1..8caf2cefc8a7 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 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf, 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 a3995c6dc1ad..d846c238b7dd 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -156,6 +156,57 @@ smb2_hdr_assemble(struct smb2_hdr *shdr, __le16 smb2_cmd, 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 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, */ 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 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, 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"); @@ -409,6 +437,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, } else { mutex_unlock(&ses->session_mutex); } +skip_add_channels:
if (smb2_command != SMB2_INTERNAL_CMD) if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0))