1 files changed, 146 insertions, 45 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index ccaa8bad336f..86d1baedf21c 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -97,6 +97,7 @@ enum {
 	Opt_persistent, Opt_nopersistent,
 	Opt_resilient, Opt_noresilient,
 	Opt_domainauto, Opt_rdma, Opt_modesid, Opt_rootfs,
+	Opt_multichannel, Opt_nomultichannel,
 	Opt_compress,
 
 	/* Mount options which take numeric value */
@@ -106,7 +107,7 @@ enum {
 	Opt_min_enc_offload,
 	Opt_blocksize, Opt_rsize, Opt_wsize, Opt_actimeo,
 	Opt_echo_interval, Opt_max_credits, Opt_handletimeout,
-	Opt_snapshot,
+	Opt_snapshot, Opt_max_channels,
 
 	/* Mount options which take string value */
 	Opt_user, Opt_pass, Opt_ip,
@@ -199,6 +200,8 @@ static const match_table_t cifs_mount_option_tokens = {
 	{ Opt_noresilient, "noresilienthandles"},
 	{ Opt_domainauto, "domainauto"},
 	{ Opt_rdma, "rdma"},
+	{ Opt_multichannel, "multichannel" },
+	{ Opt_nomultichannel, "nomultichannel" },
 
 	{ Opt_backupuid, "backupuid=%s" },
 	{ Opt_backupgid, "backupgid=%s" },
@@ -218,6 +221,7 @@ static const match_table_t cifs_mount_option_tokens = {
 	{ Opt_echo_interval, "echo_interval=%s" },
 	{ Opt_max_credits, "max_credits=%s" },
 	{ Opt_snapshot, "snapshot=%s" },
+	{ Opt_max_channels, "max_channels=%s" },
 	{ Opt_compress, "compress=%s" },
 
 	{ Opt_blank_user, "user=" },
@@ -387,7 +391,7 @@ static inline int reconn_set_ipaddr(struct TCP_Server_Info *server)
 #ifdef CONFIG_CIFS_DFS_UPCALL
 struct super_cb_data {
 	struct TCP_Server_Info *server;
-	struct cifs_sb_info *cifs_sb;
+	struct super_block *sb;
 };
 
 /* These functions must be called with server->srv_mutex held */
@@ -398,25 +402,39 @@ static void super_cb(struct super_block *sb, void *arg)
 	struct cifs_sb_info *cifs_sb;
 	struct cifs_tcon *tcon;
 
-	if (d->cifs_sb)
+	if (d->sb)
 		return;
 
 	cifs_sb = CIFS_SB(sb);
 	tcon = cifs_sb_master_tcon(cifs_sb);
 	if (tcon->ses->server == d->server)
-		d->cifs_sb = cifs_sb;
+		d->sb = sb;
 }
 
-static inline struct cifs_sb_info *
-find_super_by_tcp(struct TCP_Server_Info *server)
+static struct super_block *get_tcp_super(struct TCP_Server_Info *server)
 {
 	struct super_cb_data d = {
 		.server = server,
-		.cifs_sb = NULL,
+		.sb = NULL,
 	};
 
 	iterate_supers_type(&cifs_fs_type, super_cb, &d);
-	return d.cifs_sb ? d.cifs_sb : ERR_PTR(-ENOENT);
+
+	if (unlikely(!d.sb))
+		return ERR_PTR(-ENOENT);
+	/*
+	 * Grab an active reference in order to prevent automounts (DFS links)
+	 * of expiring and then freeing up our cifs superblock pointer while
+	 * we're doing failover.
+	 */
+	cifs_sb_active(d.sb);
+	return d.sb;
+}
+
+static inline void put_tcp_super(struct super_block *sb)
+{
+	if (!IS_ERR_OR_NULL(sb))
+		cifs_sb_deactive(sb);
 }
 
 static void reconn_inval_dfs_target(struct TCP_Server_Info *server,
@@ -480,6 +498,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
 	struct mid_q_entry *mid_entry;
 	struct list_head retry_list;
 #ifdef CONFIG_CIFS_DFS_UPCALL
+	struct super_block *sb = NULL;
 	struct cifs_sb_info *cifs_sb = NULL;
 	struct dfs_cache_tgt_list tgt_list = {0};
 	struct dfs_cache_tgt_iterator *tgt_it = NULL;
@@ -489,13 +508,15 @@ cifs_reconnect(struct TCP_Server_Info *server)
 	server->nr_targets = 1;
 #ifdef CONFIG_CIFS_DFS_UPCALL
 	spin_unlock(&GlobalMid_Lock);
-	cifs_sb = find_super_by_tcp(server);
-	if (IS_ERR(cifs_sb)) {
-		rc = PTR_ERR(cifs_sb);
+	sb = get_tcp_super(server);
+	if (IS_ERR(sb)) {
+		rc = PTR_ERR(sb);
 		cifs_dbg(FYI, "%s: will not do DFS failover: rc = %d\n",
 			 __func__, rc);
-		cifs_sb = NULL;
+		sb = NULL;
 	} else {
+		cifs_sb = CIFS_SB(sb);
+
 		rc = reconn_setup_dfs_targets(cifs_sb, &tgt_list, &tgt_it);
 		if (rc && (rc != -EOPNOTSUPP)) {
 			cifs_server_dbg(VFS, "%s: no target servers for DFS failover\n",
@@ -512,6 +533,10 @@ cifs_reconnect(struct TCP_Server_Info *server)
 		/* the demux thread will exit normally
 		next time through the loop */
 		spin_unlock(&GlobalMid_Lock);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+		dfs_cache_free_tgts(&tgt_list);
+		put_tcp_super(sb);
+#endif
 		return rc;
 	} else
 		server->tcpStatus = CifsNeedReconnect;
@@ -638,7 +663,10 @@ cifs_reconnect(struct TCP_Server_Info *server)
 				 __func__, rc);
 		}
 		dfs_cache_free_tgts(&tgt_list);
+
 	}
+
+	put_tcp_super(sb);
 #endif
 	if (server->tcpStatus == CifsNeedNegotiate)
 		mod_delayed_work(cifsiod_wq, &server->echo, 0);
@@ -905,6 +933,20 @@ dequeue_mid(struct mid_q_entry *mid, bool malformed)
 	spin_unlock(&GlobalMid_Lock);
 }
 
+static unsigned int
+smb2_get_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
+{
+	struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buffer;
+
+	/*
+	 * SMB1 does not use credits.
+	 */
+	if (server->vals->header_preamble_size)
+		return 0;
+
+	return le16_to_cpu(shdr->CreditRequest);
+}
+
 static void
 handle_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 	   char *buf, int malformed)
@@ -912,6 +954,7 @@ handle_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 	if (server->ops->check_trans2 &&
 	    server->ops->check_trans2(mid, server, buf, malformed))
 		return;
+	mid->credits_received = smb2_get_credits_from_hdr(buf, server);
 	mid->resp_buf = buf;
 	mid->large_buf = server->large_buf;
 	/* Was previous buf put in mpx struct for multi-rsp? */
@@ -1222,12 +1265,6 @@ next_pdu:
 		for (i = 0; i < num_mids; i++) {
 			if (mids[i] != NULL) {
 				mids[i]->resp_buf_size = server->pdu_size;
-				if ((mids[i]->mid_flags & MID_WAIT_CANCELLED) &&
-				    mids[i]->mid_state == MID_RESPONSE_RECEIVED &&
-				    server->ops->handle_cancelled_mid)
-					server->ops->handle_cancelled_mid(
-							mids[i]->resp_buf,
-							server);
 
 				if (!mids[i]->multiRsp || mids[i]->multiEnd)
 					mids[i]->callback(mids[i]);
@@ -1672,6 +1709,10 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
 
 	vol->echo_interval = SMB_ECHO_INTERVAL_DEFAULT;
 
+	/* default to no multichannel (single server connection) */
+	vol->multichannel = false;
+	vol->max_channels = 1;
+
 	if (!mountdata)
 		goto cifs_parse_mount_err;
 
@@ -1965,6 +2006,12 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
 		case Opt_rdma:
 			vol->rdma = true;
 			break;
+		case Opt_multichannel:
+			vol->multichannel = true;
+			break;
+		case Opt_nomultichannel:
+			vol->multichannel = false;
+			break;
 		case Opt_compress:
 			vol->compression = UNKNOWN_TYPE;
 			cifs_dbg(VFS,
@@ -2128,6 +2175,15 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
 			}
 			vol->max_credits = option;
 			break;
+		case Opt_max_channels:
+			if (get_option_ul(args, &option) || option < 1 ||
+				option > CIFS_MAX_CHANNELS) {
+				cifs_dbg(VFS, "%s: Invalid max_channels value, needs to be 1-%d\n",
+					 __func__, CIFS_MAX_CHANNELS);
+				goto cifs_parse_mount_err;
+			}
+			vol->max_channels = option;
+			break;
 
 		/* String Arguments */
 
@@ -2713,7 +2769,7 @@ cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
 		send_sig(SIGKILL, task, 1);
 }
 
-static struct TCP_Server_Info *
+struct TCP_Server_Info *
 cifs_get_tcp_session(struct smb_vol *volume_info)
 {
 	struct TCP_Server_Info *tcp_ses = NULL;
@@ -2772,7 +2828,11 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
 	       sizeof(tcp_ses->srcaddr));
 	memcpy(&tcp_ses->dstaddr, &volume_info->dstaddr,
 		sizeof(tcp_ses->dstaddr));
-	generate_random_uuid(tcp_ses->client_guid);
+	if (volume_info->use_client_guid)
+		memcpy(tcp_ses->client_guid, volume_info->client_guid,
+		       SMB2_CLIENT_GUID_SIZE);
+	else
+		generate_random_uuid(tcp_ses->client_guid);
 	/*
 	 * at this point we are the only ones with the pointer
 	 * to the struct since the kernel thread not created yet
@@ -2861,6 +2921,13 @@ static int match_session(struct cifs_ses *ses, struct smb_vol *vol)
 	    vol->sectype != ses->sectype)
 		return 0;
 
+	/*
+	 * If an existing session is limited to less channels than
+	 * requested, it should not be reused
+	 */
+	if (ses->chan_max < vol->max_channels)
+		return 0;
+
 	switch (ses->sectype) {
 	case Kerberos:
 		if (!uid_eq(vol->cred_uid, ses->cred_uid))
@@ -3031,6 +3098,14 @@ void cifs_put_smb_ses(struct cifs_ses *ses)
 	list_del_init(&ses->smb_ses_list);
 	spin_unlock(&cifs_tcp_ses_lock);
 
+	/* close any extra channels */
+	if (ses->chan_count > 1) {
+		int i;
+
+		for (i = 1; i < ses->chan_count; i++)
+			cifs_put_tcp_session(ses->chans[i].server, 0);
+	}
+
 	sesInfoFree(ses);
 	cifs_put_tcp_session(server, 0);
 }
@@ -3277,14 +3352,25 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info)
 	ses->sectype = volume_info->sectype;
 	ses->sign = volume_info->sign;
 	mutex_lock(&ses->session_mutex);
+
+	/* add server as first channel */
+	ses->chans[0].server = server;
+	ses->chan_count = 1;
+	ses->chan_max = volume_info->multichannel ? volume_info->max_channels:1;
+
 	rc = cifs_negotiate_protocol(xid, ses);
 	if (!rc)
 		rc = cifs_setup_session(xid, ses, volume_info->local_nls);
+
+	/* each channel uses a different signing key */
+	memcpy(ses->chans[0].signkey, ses->smb3signingkey,
+	       sizeof(ses->smb3signingkey));
+
 	mutex_unlock(&ses->session_mutex);
 	if (rc)
 		goto get_ses_fail;
 
-	/* success, put it on the list */
+	/* success, put it on the list and add it as first channel */
 	spin_lock(&cifs_tcp_ses_lock);
 	list_add(&ses->smb_ses_list, &server->smb_ses_list);
 	spin_unlock(&cifs_tcp_ses_lock);
@@ -4700,6 +4786,17 @@ static int is_path_remote(struct cifs_sb_info *cifs_sb, struct smb_vol *vol,
 }
 
 #ifdef CONFIG_CIFS_DFS_UPCALL
+static inline void set_root_tcon(struct cifs_sb_info *cifs_sb,
+				 struct cifs_tcon *tcon,
+				 struct cifs_tcon **root)
+{
+	spin_lock(&cifs_tcp_ses_lock);
+	tcon->tc_count++;
+	tcon->remap = cifs_remap(cifs_sb);
+	spin_unlock(&cifs_tcp_ses_lock);
+	*root = tcon;
+}
+
 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
 {
 	int rc = 0;
@@ -4801,18 +4898,10 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
 	/* Cache out resolved root server */
 	(void)dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
 			     root_path + 1, NULL, NULL);
-	/*
-	 * Save root tcon for additional DFS requests to update or create a new
-	 * DFS cache entry, or even perform DFS failover.
-	 */
-	spin_lock(&cifs_tcp_ses_lock);
-	tcon->tc_count++;
-	tcon->dfs_path = root_path;
+	kfree(root_path);
 	root_path = NULL;
-	tcon->remap = cifs_remap(cifs_sb);
-	spin_unlock(&cifs_tcp_ses_lock);
 
-	root_tcon = tcon;
+	set_root_tcon(cifs_sb, tcon, &root_tcon);
 
 	for (count = 1; ;) {
 		if (!rc && tcon) {
@@ -4849,6 +4938,15 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
 			mount_put_conns(cifs_sb, xid, server, ses, tcon);
 			rc = mount_get_conns(vol, cifs_sb, &xid, &server, &ses,
 					     &tcon);
+			/*
+			 * Ensure that DFS referrals go through new root server.
+			 */
+			if (!rc && tcon &&
+			    (tcon->share_flags & (SHI1005_FLAGS_DFS |
+						  SHI1005_FLAGS_DFS_ROOT))) {
+				cifs_put_tcon(root_tcon);
+				set_root_tcon(cifs_sb, tcon, &root_tcon);
+			}
 		}
 		if (rc) {
 			if (rc == -EACCES || rc == -EOPNOTSUPP)
@@ -4897,6 +4995,7 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
 	cifs_autodisable_serverino(cifs_sb);
 out:
 	free_xid(xid);
+	cifs_try_adding_channels(ses);
 	return mount_setup_tlink(cifs_sb, ses, tcon);
 
 error:
@@ -5142,7 +5241,7 @@ int
 cifs_negotiate_protocol(const unsigned int xid, struct cifs_ses *ses)
 {
 	int rc = 0;
-	struct TCP_Server_Info *server = ses->server;
+	struct TCP_Server_Info *server = cifs_ses_server(ses);
 
 	if (!server->ops->need_neg || !server->ops->negotiate)
 		return -ENOSYS;
@@ -5169,23 +5268,25 @@ cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
 		   struct nls_table *nls_info)
 {
 	int rc = -ENOSYS;
-	struct TCP_Server_Info *server = ses->server;
-
-	ses->capabilities = server->capabilities;
-	if (linuxExtEnabled == 0)
-		ses->capabilities &= (~server->vals->cap_unix);
+	struct TCP_Server_Info *server = cifs_ses_server(ses);
+
+	if (!ses->binding) {
+		ses->capabilities = server->capabilities;
+		if (linuxExtEnabled == 0)
+			ses->capabilities &= (~server->vals->cap_unix);
+
+		if (ses->auth_key.response) {
+			cifs_dbg(FYI, "Free previous auth_key.response = %p\n",
+				 ses->auth_key.response);
+			kfree(ses->auth_key.response);
+			ses->auth_key.response = NULL;
+			ses->auth_key.len = 0;
+		}
+	}
 
 	cifs_dbg(FYI, "Security Mode: 0x%x Capabilities: 0x%x TimeAdjust: %d\n",
 		 server->sec_mode, server->capabilities, server->timeAdj);
 
-	if (ses->auth_key.response) {
-		cifs_dbg(FYI, "Free previous auth_key.response = %p\n",
-			 ses->auth_key.response);
-		kfree(ses->auth_key.response);
-		ses->auth_key.response = NULL;
-		ses->auth_key.len = 0;
-	}
-
 	if (server->ops->sess_setup)
 		rc = server->ops->sess_setup(xid, ses, nls_info);