Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4835 insertions, 0 deletions

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
new file mode 100644
index 000000000..49fdc6dfd
--- /dev/null
+++ b/fs/smb/client/connect.c
@@ -0,0 +1,4835 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ *
+ *   Copyright (C) International Business Machines  Corp., 2002,2011
+ *   Author(s): Steve French (sfrench@us.ibm.com)
+ *
+ */
+#include <linux/fs.h>
+#include <linux/net.h>
+#include <linux/string.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/ctype.h>
+#include <linux/utsname.h>
+#include <linux/mempool.h>
+#include <linux/delay.h>
+#include <linux/completion.h>
+#include <linux/kthread.h>
+#include <linux/pagevec.h>
+#include <linux/freezer.h>
+#include <linux/namei.h>
+#include <linux/uuid.h>
+#include <linux/uaccess.h>
+#include <asm/processor.h>
+#include <linux/inet.h>
+#include <linux/module.h>
+#include <keys/user-type.h>
+#include <net/ipv6.h>
+#include <linux/parser.h>
+#include <linux/bvec.h>
+#include "cifspdu.h"
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "cifs_unicode.h"
+#include "cifs_debug.h"
+#include "cifs_fs_sb.h"
+#include "ntlmssp.h"
+#include "nterr.h"
+#include "rfc1002pdu.h"
+#include "fscache.h"
+#include "smb2proto.h"
+#include "smbdirect.h"
+#include "dns_resolve.h"
+#ifdef CONFIG_CIFS_DFS_UPCALL
+#include "dfs_cache.h"
+#endif
+#include "fs_context.h"
+#include "cifs_swn.h"
+
+extern mempool_t *cifs_req_poolp;
+extern bool disable_legacy_dialects;
+
+/* FIXME: should these be tunable? */
+#define TLINK_ERROR_EXPIRE	(1 * HZ)
+#define TLINK_IDLE_EXPIRE	(600 * HZ)
+
+/* Drop the connection to not overload the server */
+#define MAX_STATUS_IO_TIMEOUT   5
+
+struct mount_ctx {
+	struct cifs_sb_info *cifs_sb;
+	struct smb3_fs_context *fs_ctx;
+	unsigned int xid;
+	struct TCP_Server_Info *server;
+	struct cifs_ses *ses;
+	struct cifs_tcon *tcon;
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	struct cifs_ses *root_ses;
+	uuid_t mount_id;
+	char *origin_fullpath, *leaf_fullpath;
+#endif
+};
+
+static int ip_connect(struct TCP_Server_Info *server);
+static int generic_ip_connect(struct TCP_Server_Info *server);
+static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);
+static void cifs_prune_tlinks(struct work_struct *work);
+
+/*
+ * Resolve hostname and set ip addr in tcp ses. Useful for hostnames that may
+ * get their ip addresses changed at some point.
+ *
+ * This should be called with server->srv_mutex held.
+ */
+static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
+{
+	int rc;
+	int len;
+	char *unc, *ipaddr = NULL;
+	time64_t expiry, now;
+	unsigned long ttl = SMB_DNS_RESOLVE_INTERVAL_DEFAULT;
+
+	if (!server->hostname)
+		return -EINVAL;
+
+	/* if server hostname isn't populated, there's nothing to do here */
+	if (server->hostname[0] == '\0')
+		return 0;
+
+	len = strlen(server->hostname) + 3;
+
+	unc = kmalloc(len, GFP_KERNEL);
+	if (!unc) {
+		cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);
+		return -ENOMEM;
+	}
+	scnprintf(unc, len, "\\\\%s", server->hostname);
+
+	rc = dns_resolve_server_name_to_ip(unc, &ipaddr, &expiry);
+	kfree(unc);
+
+	if (rc < 0) {
+		cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n",
+			 __func__, server->hostname, rc);
+		goto requeue_resolve;
+	}
+
+	spin_lock(&server->srv_lock);
+	rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,
+				  strlen(ipaddr));
+	spin_unlock(&server->srv_lock);
+	kfree(ipaddr);
+
+	/* rc == 1 means success here */
+	if (rc) {
+		now = ktime_get_real_seconds();
+		if (expiry && expiry > now)
+			/*
+			 * To make sure we don't use the cached entry, retry 1s
+			 * after expiry.
+			 */
+			ttl = max_t(unsigned long, expiry - now, SMB_DNS_RESOLVE_INTERVAL_MIN) + 1;
+	}
+	rc = !rc ? -1 : 0;
+
+requeue_resolve:
+	cifs_dbg(FYI, "%s: next dns resolution scheduled for %lu seconds in the future\n",
+		 __func__, ttl);
+	mod_delayed_work(cifsiod_wq, &server->resolve, (ttl * HZ));
+
+	return rc;
+}
+
+static void smb2_query_server_interfaces(struct work_struct *work)
+{
+	int rc;
+	struct cifs_tcon *tcon = container_of(work,
+					struct cifs_tcon,
+					query_interfaces.work);
+
+	/*
+	 * query server network interfaces, in case they change
+	 */
+	rc = SMB3_request_interfaces(0, tcon, false);
+	if (rc) {
+		cifs_dbg(FYI, "%s: failed to query server interfaces: %d\n",
+				__func__, rc);
+	}
+
+	queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
+			   (SMB_INTERFACE_POLL_INTERVAL * HZ));
+}
+
+static void cifs_resolve_server(struct work_struct *work)
+{
+	int rc;
+	struct TCP_Server_Info *server = container_of(work,
+					struct TCP_Server_Info, resolve.work);
+
+	cifs_server_lock(server);
+
+	/*
+	 * Resolve the hostname again to make sure that IP address is up-to-date.
+	 */
+	rc = reconn_set_ipaddr_from_hostname(server);
+	if (rc) {
+		cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
+				__func__, rc);
+	}
+
+	cifs_server_unlock(server);
+}
+
+/*
+ * Update the tcpStatus for the server.
+ * This is used to signal the cifsd thread to call cifs_reconnect
+ * ONLY cifsd thread should call cifs_reconnect. For any other
+ * thread, use this function
+ *
+ * @server: the tcp ses for which reconnect is needed
+ * @all_channels: if this needs to be done for all channels
+ */
+void
+cifs_signal_cifsd_for_reconnect(struct TCP_Server_Info *server,
+				bool all_channels)
+{
+	struct TCP_Server_Info *pserver;
+	struct cifs_ses *ses;
+	int i;
+
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
+	/* if we need to signal just this channel */
+	if (!all_channels) {
+		spin_lock(&server->srv_lock);
+		if (server->tcpStatus != CifsExiting)
+			server->tcpStatus = CifsNeedReconnect;
+		spin_unlock(&server->srv_lock);
+		return;
+	}
+
+	spin_lock(&cifs_tcp_ses_lock);
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+		spin_lock(&ses->chan_lock);
+		for (i = 0; i < ses->chan_count; i++) {
+			spin_lock(&ses->chans[i].server->srv_lock);
+			ses->chans[i].server->tcpStatus = CifsNeedReconnect;
+			spin_unlock(&ses->chans[i].server->srv_lock);
+		}
+		spin_unlock(&ses->chan_lock);
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+}
+
+/*
+ * Mark all sessions and tcons for reconnect.
+ * IMPORTANT: make sure that this gets called only from
+ * cifsd thread. For any other thread, use
+ * cifs_signal_cifsd_for_reconnect
+ *
+ * @server: the tcp ses for which reconnect is needed
+ * @server needs to be previously set to CifsNeedReconnect.
+ * @mark_smb_session: whether even sessions need to be marked
+ */
+void
+cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server,
+				      bool mark_smb_session)
+{
+	struct TCP_Server_Info *pserver;
+	struct cifs_ses *ses, *nses;
+	struct cifs_tcon *tcon;
+
+	/*
+	 * before reconnecting the tcp session, mark the smb session (uid) and the tid bad so they
+	 * are not used until reconnected.
+	 */
+	cifs_dbg(FYI, "%s: marking necessary sessions and tcons for reconnect\n", __func__);
+
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
+
+	spin_lock(&cifs_tcp_ses_lock);
+	list_for_each_entry_safe(ses, nses, &pserver->smb_ses_list, smb_ses_list) {
+		/* check if iface is still active */
+		spin_lock(&ses->chan_lock);
+		if (!cifs_chan_is_iface_active(ses, server)) {
+			spin_unlock(&ses->chan_lock);
+			cifs_chan_update_iface(ses, server);
+			spin_lock(&ses->chan_lock);
+		}
+
+		if (!mark_smb_session && cifs_chan_needs_reconnect(ses, server)) {
+			spin_unlock(&ses->chan_lock);
+			continue;
+		}
+
+		if (mark_smb_session)
+			CIFS_SET_ALL_CHANS_NEED_RECONNECT(ses);
+		else
+			cifs_chan_set_need_reconnect(ses, server);
+
+		cifs_dbg(FYI, "%s: channel connect bitmap: 0x%lx\n",
+			 __func__, ses->chans_need_reconnect);
+
+		/* If all channels need reconnect, then tcon needs reconnect */
+		if (!mark_smb_session && !CIFS_ALL_CHANS_NEED_RECONNECT(ses)) {
+			spin_unlock(&ses->chan_lock);
+			continue;
+		}
+		spin_unlock(&ses->chan_lock);
+
+		spin_lock(&ses->ses_lock);
+		ses->ses_status = SES_NEED_RECON;
+		spin_unlock(&ses->ses_lock);
+
+		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
+			tcon->need_reconnect = true;
+			spin_lock(&tcon->tc_lock);
+			tcon->status = TID_NEED_RECON;
+			spin_unlock(&tcon->tc_lock);
+		}
+		if (ses->tcon_ipc) {
+			ses->tcon_ipc->need_reconnect = true;
+			spin_lock(&ses->tcon_ipc->tc_lock);
+			ses->tcon_ipc->status = TID_NEED_RECON;
+			spin_unlock(&ses->tcon_ipc->tc_lock);
+		}
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+}
+
+static void
+cifs_abort_connection(struct TCP_Server_Info *server)
+{
+	struct mid_q_entry *mid, *nmid;
+	struct list_head retry_list;
+
+	server->maxBuf = 0;
+	server->max_read = 0;
+
+	/* do not want to be sending data on a socket we are freeing */
+	cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
+	cifs_server_lock(server);
+	if (server->ssocket) {
+		cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n", server->ssocket->state,
+			 server->ssocket->flags);
+		kernel_sock_shutdown(server->ssocket, SHUT_WR);
+		cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n", server->ssocket->state,
+			 server->ssocket->flags);
+		sock_release(server->ssocket);
+		server->ssocket = NULL;
+	}
+	server->sequence_number = 0;
+	server->session_estab = false;
+	kfree_sensitive(server->session_key.response);
+	server->session_key.response = NULL;
+	server->session_key.len = 0;
+	server->lstrp = jiffies;
+
+	/* mark submitted MIDs for retry and issue callback */
+	INIT_LIST_HEAD(&retry_list);
+	cifs_dbg(FYI, "%s: moving mids to private list\n", __func__);
+	spin_lock(&server->mid_lock);
+	list_for_each_entry_safe(mid, nmid, &server->pending_mid_q, qhead) {
+		kref_get(&mid->refcount);
+		if (mid->mid_state == MID_REQUEST_SUBMITTED)
+			mid->mid_state = MID_RETRY_NEEDED;
+		list_move(&mid->qhead, &retry_list);
+		mid->mid_flags |= MID_DELETED;
+	}
+	spin_unlock(&server->mid_lock);
+	cifs_server_unlock(server);
+
+	cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
+	list_for_each_entry_safe(mid, nmid, &retry_list, qhead) {
+		list_del_init(&mid->qhead);
+		mid->callback(mid);
+		release_mid(mid);
+	}
+
+	if (cifs_rdma_enabled(server)) {
+		cifs_server_lock(server);
+		smbd_destroy(server);
+		cifs_server_unlock(server);
+	}
+}
+
+static bool cifs_tcp_ses_needs_reconnect(struct TCP_Server_Info *server, int num_targets)
+{
+	spin_lock(&server->srv_lock);
+	server->nr_targets = num_targets;
+	if (server->tcpStatus == CifsExiting) {
+		/* the demux thread will exit normally next time through the loop */
+		spin_unlock(&server->srv_lock);
+		wake_up(&server->response_q);
+		return false;
+	}
+
+	cifs_dbg(FYI, "Mark tcp session as need reconnect\n");
+	trace_smb3_reconnect(server->CurrentMid, server->conn_id,
+			     server->hostname);
+	server->tcpStatus = CifsNeedReconnect;
+
+	spin_unlock(&server->srv_lock);
+	return true;
+}
+
+/*
+ * cifs tcp session reconnection
+ *
+ * mark tcp session as reconnecting so temporarily locked
+ * mark all smb sessions as reconnecting for tcp session
+ * reconnect tcp session
+ * wake up waiters on reconnection? - (not needed currently)
+ *
+ * if mark_smb_session is passed as true, unconditionally mark
+ * the smb session (and tcon) for reconnect as well. This value
+ * doesn't really matter for non-multichannel scenario.
+ *
+ */
+static int __cifs_reconnect(struct TCP_Server_Info *server,
+			    bool mark_smb_session)
+{
+	int rc = 0;
+
+	if (!cifs_tcp_ses_needs_reconnect(server, 1))
+		return 0;
+
+	cifs_mark_tcp_ses_conns_for_reconnect(server, mark_smb_session);
+
+	cifs_abort_connection(server);
+
+	do {
+		try_to_freeze();
+		cifs_server_lock(server);
+
+		if (!cifs_swn_set_server_dstaddr(server)) {
+			/* resolve the hostname again to make sure that IP address is up-to-date */
+			rc = reconn_set_ipaddr_from_hostname(server);
+			cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
+		}
+
+		if (cifs_rdma_enabled(server))
+			rc = smbd_reconnect(server);
+		else
+			rc = generic_ip_connect(server);
+		if (rc) {
+			cifs_server_unlock(server);
+			cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
+			msleep(3000);
+		} else {
+			atomic_inc(&tcpSesReconnectCount);
+			set_credits(server, 1);
+			spin_lock(&server->srv_lock);
+			if (server->tcpStatus != CifsExiting)
+				server->tcpStatus = CifsNeedNegotiate;
+			spin_unlock(&server->srv_lock);
+			cifs_swn_reset_server_dstaddr(server);
+			cifs_server_unlock(server);
+			mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
+		}
+	} while (server->tcpStatus == CifsNeedReconnect);
+
+	spin_lock(&server->srv_lock);
+	if (server->tcpStatus == CifsNeedNegotiate)
+		mod_delayed_work(cifsiod_wq, &server->echo, 0);
+	spin_unlock(&server->srv_lock);
+
+	wake_up(&server->response_q);
+	return rc;
+}
+
+#ifdef CONFIG_CIFS_DFS_UPCALL
+static int __reconnect_target_unlocked(struct TCP_Server_Info *server, const char *target)
+{
+	int rc;
+	char *hostname;
+
+	if (!cifs_swn_set_server_dstaddr(server)) {
+		if (server->hostname != target) {
+			hostname = extract_hostname(target);
+			if (!IS_ERR(hostname)) {
+				spin_lock(&server->srv_lock);
+				kfree(server->hostname);
+				server->hostname = hostname;
+				spin_unlock(&server->srv_lock);
+			} else {
+				cifs_dbg(FYI, "%s: couldn't extract hostname or address from dfs target: %ld\n",
+					 __func__, PTR_ERR(hostname));
+				cifs_dbg(FYI, "%s: default to last target server: %s\n", __func__,
+					 server->hostname);
+			}
+		}
+		/* resolve the hostname again to make sure that IP address is up-to-date. */
+		rc = reconn_set_ipaddr_from_hostname(server);
+		cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
+	}
+	/* Reconnect the socket */
+	if (cifs_rdma_enabled(server))
+		rc = smbd_reconnect(server);
+	else
+		rc = generic_ip_connect(server);
+
+	return rc;
+}
+
+static int reconnect_target_unlocked(struct TCP_Server_Info *server, struct dfs_cache_tgt_list *tl,
+				     struct dfs_cache_tgt_iterator **target_hint)
+{
+	int rc;
+	struct dfs_cache_tgt_iterator *tit;
+
+	*target_hint = NULL;
+
+	/* If dfs target list is empty, then reconnect to last server */
+	tit = dfs_cache_get_tgt_iterator(tl);
+	if (!tit)
+		return __reconnect_target_unlocked(server, server->hostname);
+
+	/* Otherwise, try every dfs target in @tl */
+	for (; tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
+		rc = __reconnect_target_unlocked(server, dfs_cache_get_tgt_name(tit));
+		if (!rc) {
+			*target_hint = tit;
+			break;
+		}
+	}
+	return rc;
+}
+
+static int reconnect_dfs_server(struct TCP_Server_Info *server)
+{
+	int rc = 0;
+	const char *refpath = server->current_fullpath + 1;
+	struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
+	struct dfs_cache_tgt_iterator *target_hint = NULL;
+	int num_targets = 0;
+
+	/*
+	 * Determine the number of dfs targets the referral path in @cifs_sb resolves to.
+	 *
+	 * smb2_reconnect() needs to know how long it should wait based upon the number of dfs
+	 * targets (server->nr_targets).  It's also possible that the cached referral was cleared
+	 * through /proc/fs/cifs/dfscache or the target list is empty due to server settings after
+	 * refreshing the referral, so, in this case, default it to 1.
+	 */
+	if (!dfs_cache_noreq_find(refpath, NULL, &tl))
+		num_targets = dfs_cache_get_nr_tgts(&tl);
+	if (!num_targets)
+		num_targets = 1;
+
+	if (!cifs_tcp_ses_needs_reconnect(server, num_targets))
+		return 0;
+
+	/*
+	 * Unconditionally mark all sessions & tcons for reconnect as we might be connecting to a
+	 * different server or share during failover.  It could be improved by adding some logic to
+	 * only do that in case it connects to a different server or share, though.
+	 */
+	cifs_mark_tcp_ses_conns_for_reconnect(server, true);
+
+	cifs_abort_connection(server);
+
+	do {
+		try_to_freeze();
+		cifs_server_lock(server);
+
+		rc = reconnect_target_unlocked(server, &tl, &target_hint);
+		if (rc) {
+			/* Failed to reconnect socket */
+			cifs_server_unlock(server);
+			cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
+			msleep(3000);
+			continue;
+		}
+		/*
+		 * Socket was created.  Update tcp session status to CifsNeedNegotiate so that a
+		 * process waiting for reconnect will know it needs to re-establish session and tcon
+		 * through the reconnected target server.
+		 */
+		atomic_inc(&tcpSesReconnectCount);
+		set_credits(server, 1);
+		spin_lock(&server->srv_lock);
+		if (server->tcpStatus != CifsExiting)
+			server->tcpStatus = CifsNeedNegotiate;
+		spin_unlock(&server->srv_lock);
+		cifs_swn_reset_server_dstaddr(server);
+		cifs_server_unlock(server);
+		mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
+	} while (server->tcpStatus == CifsNeedReconnect);
+
+	if (target_hint)
+		dfs_cache_noreq_update_tgthint(refpath, target_hint);
+
+	dfs_cache_free_tgts(&tl);
+
+	/* Need to set up echo worker again once connection has been established */
+	spin_lock(&server->srv_lock);
+	if (server->tcpStatus == CifsNeedNegotiate)
+		mod_delayed_work(cifsiod_wq, &server->echo, 0);
+	spin_unlock(&server->srv_lock);
+
+	wake_up(&server->response_q);
+	return rc;
+}
+
+int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
+{
+	/* If tcp session is not an dfs connection, then reconnect to last target server */
+	spin_lock(&server->srv_lock);
+	if (!server->is_dfs_conn) {
+		spin_unlock(&server->srv_lock);
+		return __cifs_reconnect(server, mark_smb_session);
+	}
+	spin_unlock(&server->srv_lock);
+
+	mutex_lock(&server->refpath_lock);
+	if (!server->origin_fullpath || !server->leaf_fullpath) {
+		mutex_unlock(&server->refpath_lock);
+		return __cifs_reconnect(server, mark_smb_session);
+	}
+	mutex_unlock(&server->refpath_lock);
+
+	return reconnect_dfs_server(server);
+}
+#else
+int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
+{
+	return __cifs_reconnect(server, mark_smb_session);
+}
+#endif
+
+static void
+cifs_echo_request(struct work_struct *work)
+{
+	int rc;
+	struct TCP_Server_Info *server = container_of(work,
+					struct TCP_Server_Info, echo.work);
+
+	/*
+	 * We cannot send an echo if it is disabled.
+	 * Also, no need to ping if we got a response recently.
+	 */
+
+	if (server->tcpStatus == CifsNeedReconnect ||
+	    server->tcpStatus == CifsExiting ||
+	    server->tcpStatus == CifsNew ||
+	    (server->ops->can_echo && !server->ops->can_echo(server)) ||
+	    time_before(jiffies, server->lstrp + server->echo_interval - HZ))
+		goto requeue_echo;
+
+	rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
+	cifs_server_dbg(FYI, "send echo request: rc = %d\n", rc);
+
+	/* Check witness registrations */
+	cifs_swn_check();
+
+requeue_echo:
+	queue_delayed_work(cifsiod_wq, &server->echo, server->echo_interval);
+}
+
+static bool
+allocate_buffers(struct TCP_Server_Info *server)
+{
+	if (!server->bigbuf) {
+		server->bigbuf = (char *)cifs_buf_get();
+		if (!server->bigbuf) {
+			cifs_server_dbg(VFS, "No memory for large SMB response\n");
+			msleep(3000);
+			/* retry will check if exiting */
+			return false;
+		}
+	} else if (server->large_buf) {
+		/* we are reusing a dirty large buf, clear its start */
+		memset(server->bigbuf, 0, HEADER_SIZE(server));
+	}
+
+	if (!server->smallbuf) {
+		server->smallbuf = (char *)cifs_small_buf_get();
+		if (!server->smallbuf) {
+			cifs_server_dbg(VFS, "No memory for SMB response\n");
+			msleep(1000);
+			/* retry will check if exiting */
+			return false;
+		}
+		/* beginning of smb buffer is cleared in our buf_get */
+	} else {
+		/* if existing small buf clear beginning */
+		memset(server->smallbuf, 0, HEADER_SIZE(server));
+	}
+
+	return true;
+}
+
+static bool
+server_unresponsive(struct TCP_Server_Info *server)
+{
+	/*
+	 * We need to wait 3 echo intervals to make sure we handle such
+	 * situations right:
+	 * 1s  client sends a normal SMB request
+	 * 2s  client gets a response
+	 * 30s echo workqueue job pops, and decides we got a response recently
+	 *     and don't need to send another
+	 * ...
+	 * 65s kernel_recvmsg times out, and we see that we haven't gotten
+	 *     a response in >60s.
+	 */
+	spin_lock(&server->srv_lock);
+	if ((server->tcpStatus == CifsGood ||
+	    server->tcpStatus == CifsNeedNegotiate) &&
+	    (!server->ops->can_echo || server->ops->can_echo(server)) &&
+	    time_after(jiffies, server->lstrp + 3 * server->echo_interval)) {
+		spin_unlock(&server->srv_lock);
+		cifs_server_dbg(VFS, "has not responded in %lu seconds. Reconnecting...\n",
+			 (3 * server->echo_interval) / HZ);
+		cifs_reconnect(server, false);
+		return true;
+	}
+	spin_unlock(&server->srv_lock);
+
+	return false;
+}
+
+static inline bool
+zero_credits(struct TCP_Server_Info *server)
+{
+	int val;
+
+	spin_lock(&server->req_lock);
+	val = server->credits + server->echo_credits + server->oplock_credits;
+	if (server->in_flight == 0 && val == 0) {
+		spin_unlock(&server->req_lock);
+		return true;
+	}
+	spin_unlock(&server->req_lock);
+	return false;
+}
+
+static int
+cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
+{
+	int length = 0;
+	int total_read;
+
+	for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
+		try_to_freeze();
+
+		/* reconnect if no credits and no requests in flight */
+		if (zero_credits(server)) {
+			cifs_reconnect(server, false);
+			return -ECONNABORTED;
+		}
+
+		if (server_unresponsive(server))
+			return -ECONNABORTED;
+		if (cifs_rdma_enabled(server) && server->smbd_conn)
+			length = smbd_recv(server->smbd_conn, smb_msg);
+		else
+			length = sock_recvmsg(server->ssocket, smb_msg, 0);
+
+		spin_lock(&server->srv_lock);
+		if (server->tcpStatus == CifsExiting) {
+			spin_unlock(&server->srv_lock);
+			return -ESHUTDOWN;
+		}
+
+		if (server->tcpStatus == CifsNeedReconnect) {
+			spin_unlock(&server->srv_lock);
+			cifs_reconnect(server, false);
+			return -ECONNABORTED;
+		}
+		spin_unlock(&server->srv_lock);
+
+		if (length == -ERESTARTSYS ||
+		    length == -EAGAIN ||
+		    length == -EINTR) {
+			/*
+			 * Minimum sleep to prevent looping, allowing socket
+			 * to clear and app threads to set tcpStatus
+			 * CifsNeedReconnect if server hung.
+			 */
+			usleep_range(1000, 2000);
+			length = 0;
+			continue;
+		}
+
+		if (length <= 0) {
+			cifs_dbg(FYI, "Received no data or error: %d\n", length);
+			cifs_reconnect(server, false);
+			return -ECONNABORTED;
+		}
+	}
+	return total_read;
+}
+
+int
+cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
+		      unsigned int to_read)
+{
+	struct msghdr smb_msg = {};
+	struct kvec iov = {.iov_base = buf, .iov_len = to_read};
+	iov_iter_kvec(&smb_msg.msg_iter, ITER_DEST, &iov, 1, to_read);
+
+	return cifs_readv_from_socket(server, &smb_msg);
+}
+
+ssize_t
+cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)
+{
+	struct msghdr smb_msg = {};
+
+	/*
+	 *  iov_iter_discard already sets smb_msg.type and count and iov_offset
+	 *  and cifs_readv_from_socket sets msg_control and msg_controllen
+	 *  so little to initialize in struct msghdr
+	 */
+	iov_iter_discard(&smb_msg.msg_iter, ITER_DEST, to_read);
+
+	return cifs_readv_from_socket(server, &smb_msg);
+}
+
+int
+cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
+	unsigned int page_offset, unsigned int to_read)
+{
+	struct msghdr smb_msg = {};
+	struct bio_vec bv = {
+		.bv_page = page, .bv_len = to_read, .bv_offset = page_offset};
+	iov_iter_bvec(&smb_msg.msg_iter, ITER_DEST, &bv, 1, to_read);
+	return cifs_readv_from_socket(server, &smb_msg);
+}
+
+static bool
+is_smb_response(struct TCP_Server_Info *server, unsigned char type)
+{
+	/*
+	 * The first byte big endian of the length field,
+	 * is actually not part of the length but the type
+	 * with the most common, zero, as regular data.
+	 */
+	switch (type) {
+	case RFC1002_SESSION_MESSAGE:
+		/* Regular SMB response */
+		return true;
+	case RFC1002_SESSION_KEEP_ALIVE:
+		cifs_dbg(FYI, "RFC 1002 session keep alive\n");
+		break;
+	case RFC1002_POSITIVE_SESSION_RESPONSE:
+		cifs_dbg(FYI, "RFC 1002 positive session response\n");
+		break;
+	case RFC1002_NEGATIVE_SESSION_RESPONSE:
+		/*
+		 * We get this from Windows 98 instead of an error on
+		 * SMB negprot response.
+		 */
+		cifs_dbg(FYI, "RFC 1002 negative session response\n");
+		/* give server a second to clean up */
+		msleep(1000);
+		/*
+		 * Always try 445 first on reconnect since we get NACK
+		 * on some if we ever connected to port 139 (the NACK
+		 * is since we do not begin with RFC1001 session
+		 * initialize frame).
+		 */
+		cifs_set_port((struct sockaddr *)&server->dstaddr, CIFS_PORT);
+		cifs_reconnect(server, true);
+		break;
+	default:
+		cifs_server_dbg(VFS, "RFC 1002 unknown response type 0x%x\n", type);
+		cifs_reconnect(server, true);
+	}
+
+	return false;
+}
+
+void
+dequeue_mid(struct mid_q_entry *mid, bool malformed)
+{
+#ifdef CONFIG_CIFS_STATS2
+	mid->when_received = jiffies;
+#endif
+	spin_lock(&mid->server->mid_lock);
+	if (!malformed)
+		mid->mid_state = MID_RESPONSE_RECEIVED;
+	else
+		mid->mid_state = MID_RESPONSE_MALFORMED;
+	/*
+	 * Trying to handle/dequeue a mid after the send_recv()
+	 * function has finished processing it is a bug.
+	 */
+	if (mid->mid_flags & MID_DELETED) {
+		spin_unlock(&mid->server->mid_lock);
+		pr_warn_once("trying to dequeue a deleted mid\n");
+	} else {
+		list_del_init(&mid->qhead);
+		mid->mid_flags |= MID_DELETED;
+		spin_unlock(&mid->server->mid_lock);
+	}
+}
+
+static unsigned int
+smb2_get_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
+{
+	struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
+
+	/*
+	 * SMB1 does not use credits.
+	 */
+	if (is_smb1(server))
+		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)
+{
+	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? */
+	if (!mid->multiRsp) {
+		/* smb buffer will be freed by user thread */
+		if (server->large_buf)
+			server->bigbuf = NULL;
+		else
+			server->smallbuf = NULL;
+	}
+	dequeue_mid(mid, malformed);
+}
+
+int
+cifs_enable_signing(struct TCP_Server_Info *server, bool mnt_sign_required)
+{
+	bool srv_sign_required = server->sec_mode & server->vals->signing_required;
+	bool srv_sign_enabled = server->sec_mode & server->vals->signing_enabled;
+	bool mnt_sign_enabled;
+
+	/*
+	 * Is signing required by mnt options? If not then check
+	 * global_secflags to see if it is there.
+	 */
+	if (!mnt_sign_required)
+		mnt_sign_required = ((global_secflags & CIFSSEC_MUST_SIGN) ==
+						CIFSSEC_MUST_SIGN);
+
+	/*
+	 * If signing is required then it's automatically enabled too,
+	 * otherwise, check to see if the secflags allow it.
+	 */
+	mnt_sign_enabled = mnt_sign_required ? mnt_sign_required :
+				(global_secflags & CIFSSEC_MAY_SIGN);
+
+	/* If server requires signing, does client allow it? */
+	if (srv_sign_required) {
+		if (!mnt_sign_enabled) {
+			cifs_dbg(VFS, "Server requires signing, but it's disabled in SecurityFlags!\n");
+			return -EOPNOTSUPP;
+		}
+		server->sign = true;
+	}
+
+	/* If client requires signing, does server allow it? */
+	if (mnt_sign_required) {
+		if (!srv_sign_enabled) {
+			cifs_dbg(VFS, "Server does not support signing!\n");
+			return -EOPNOTSUPP;
+		}
+		server->sign = true;
+	}
+
+	if (cifs_rdma_enabled(server) && server->sign)
+		cifs_dbg(VFS, "Signing is enabled, and RDMA read/write will be disabled\n");
+
+	return 0;
+}
+
+
+static void clean_demultiplex_info(struct TCP_Server_Info *server)
+{
+	int length;
+
+	/* take it off the list, if it's not already */
+	spin_lock(&server->srv_lock);
+	list_del_init(&server->tcp_ses_list);
+	spin_unlock(&server->srv_lock);
+
+	cancel_delayed_work_sync(&server->echo);
+	cancel_delayed_work_sync(&server->resolve);
+
+	spin_lock(&server->srv_lock);
+	server->tcpStatus = CifsExiting;
+	spin_unlock(&server->srv_lock);
+	wake_up_all(&server->response_q);
+
+	/* check if we have blocked requests that need to free */
+	spin_lock(&server->req_lock);
+	if (server->credits <= 0)
+		server->credits = 1;
+	spin_unlock(&server->req_lock);
+	/*
+	 * Although there should not be any requests blocked on this queue it
+	 * can not hurt to be paranoid and try to wake up requests that may
+	 * haven been blocked when more than 50 at time were on the wire to the
+	 * same server - they now will see the session is in exit state and get
+	 * out of SendReceive.
+	 */
+	wake_up_all(&server->request_q);
+	/* give those requests time to exit */
+	msleep(125);
+	if (cifs_rdma_enabled(server))
+		smbd_destroy(server);
+	if (server->ssocket) {
+		sock_release(server->ssocket);
+		server->ssocket = NULL;
+	}
+
+	if (!list_empty(&server->pending_mid_q)) {
+		struct list_head dispose_list;
+		struct mid_q_entry *mid_entry;
+		struct list_head *tmp, *tmp2;
+
+		INIT_LIST_HEAD(&dispose_list);
+		spin_lock(&server->mid_lock);
+		list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
+			mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
+			cifs_dbg(FYI, "Clearing mid %llu\n", mid_entry->mid);
+			kref_get(&mid_entry->refcount);
+			mid_entry->mid_state = MID_SHUTDOWN;
+			list_move(&mid_entry->qhead, &dispose_list);
+			mid_entry->mid_flags |= MID_DELETED;
+		}
+		spin_unlock(&server->mid_lock);
+
+		/* now walk dispose list and issue callbacks */
+		list_for_each_safe(tmp, tmp2, &dispose_list) {
+			mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
+			cifs_dbg(FYI, "Callback mid %llu\n", mid_entry->mid);
+			list_del_init(&mid_entry->qhead);
+			mid_entry->callback(mid_entry);
+			release_mid(mid_entry);
+		}
+		/* 1/8th of sec is more than enough time for them to exit */
+		msleep(125);
+	}
+
+	if (!list_empty(&server->pending_mid_q)) {
+		/*
+		 * mpx threads have not exited yet give them at least the smb
+		 * send timeout time for long ops.
+		 *
+		 * Due to delays on oplock break requests, we need to wait at
+		 * least 45 seconds before giving up on a request getting a
+		 * response and going ahead and killing cifsd.
+		 */
+		cifs_dbg(FYI, "Wait for exit from demultiplex thread\n");
+		msleep(46000);
+		/*
+		 * If threads still have not exited they are probably never
+		 * coming home not much else we can do but free the memory.
+		 */
+	}
+
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	kfree(server->origin_fullpath);
+	kfree(server->leaf_fullpath);
+#endif
+	kfree(server);
+
+	length = atomic_dec_return(&tcpSesAllocCount);
+	if (length > 0)
+		mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
+}
+
+static int
+standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
+{
+	int length;
+	char *buf = server->smallbuf;
+	unsigned int pdu_length = server->pdu_size;
+
+	/* make sure this will fit in a large buffer */
+	if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
+	    HEADER_PREAMBLE_SIZE(server)) {
+		cifs_server_dbg(VFS, "SMB response too long (%u bytes)\n", pdu_length);
+		cifs_reconnect(server, true);
+		return -ECONNABORTED;
+	}
+
+	/* switch to large buffer if too big for a small one */
+	if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
+		server->large_buf = true;
+		memcpy(server->bigbuf, buf, server->total_read);
+		buf = server->bigbuf;
+	}
+
+	/* now read the rest */
+	length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
+				       pdu_length - MID_HEADER_SIZE(server));
+
+	if (length < 0)
+		return length;
+	server->total_read += length;
+
+	dump_smb(buf, server->total_read);
+
+	return cifs_handle_standard(server, mid);
+}
+
+int
+cifs_handle_standard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
+{
+	char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
+	int rc;
+
+	/*
+	 * We know that we received enough to get to the MID as we
+	 * checked the pdu_length earlier. Now check to see
+	 * if the rest of the header is OK.
+	 *
+	 * 48 bytes is enough to display the header and a little bit
+	 * into the payload for debugging purposes.
+	 */
+	rc = server->ops->check_message(buf, server->total_read, server);
+	if (rc)
+		cifs_dump_mem("Bad SMB: ", buf,
+			min_t(unsigned int, server->total_read, 48));
+
+	if (server->ops->is_session_expired &&
+	    server->ops->is_session_expired(buf)) {
+		cifs_reconnect(server, true);
+		return -1;
+	}
+
+	if (server->ops->is_status_pending &&
+	    server->ops->is_status_pending(buf, server))
+		return -1;
+
+	if (!mid)
+		return rc;
+
+	handle_mid(mid, server, buf, rc);
+	return 0;
+}
+
+static void
+smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
+{
+	struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
+	int scredits, in_flight;
+
+	/*
+	 * SMB1 does not use credits.
+	 */
+	if (is_smb1(server))
+		return;
+
+	if (shdr->CreditRequest) {
+		spin_lock(&server->req_lock);
+		server->credits += le16_to_cpu(shdr->CreditRequest);
+		scredits = server->credits;
+		in_flight = server->in_flight;
+		spin_unlock(&server->req_lock);
+		wake_up(&server->request_q);
+
+		trace_smb3_hdr_credits(server->CurrentMid,
+				server->conn_id, server->hostname, scredits,
+				le16_to_cpu(shdr->CreditRequest), in_flight);
+		cifs_server_dbg(FYI, "%s: added %u credits total=%d\n",
+				__func__, le16_to_cpu(shdr->CreditRequest),
+				scredits);
+	}
+}
+
+
+static int
+cifs_demultiplex_thread(void *p)
+{
+	int i, num_mids, length;
+	struct TCP_Server_Info *server = p;
+	unsigned int pdu_length;
+	unsigned int next_offset;
+	char *buf = NULL;
+	struct task_struct *task_to_wake = NULL;
+	struct mid_q_entry *mids[MAX_COMPOUND];
+	char *bufs[MAX_COMPOUND];
+	unsigned int noreclaim_flag, num_io_timeout = 0;
+	bool pending_reconnect = false;
+
+	noreclaim_flag = memalloc_noreclaim_save();
+	cifs_dbg(FYI, "Demultiplex PID: %d\n", task_pid_nr(current));
+
+	length = atomic_inc_return(&tcpSesAllocCount);
+	if (length > 1)
+		mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
+
+	set_freezable();
+	allow_kernel_signal(SIGKILL);
+	while (server->tcpStatus != CifsExiting) {
+		if (try_to_freeze())
+			continue;
+
+		if (!allocate_buffers(server))
+			continue;
+
+		server->large_buf = false;
+		buf = server->smallbuf;
+		pdu_length = 4; /* enough to get RFC1001 header */
+
+		length = cifs_read_from_socket(server, buf, pdu_length);
+		if (length < 0)
+			continue;
+
+		if (is_smb1(server))
+			server->total_read = length;
+		else
+			server->total_read = 0;
+
+		/*
+		 * The right amount was read from socket - 4 bytes,
+		 * so we can now interpret the length field.
+		 */
+		pdu_length = get_rfc1002_length(buf);
+
+		cifs_dbg(FYI, "RFC1002 header 0x%x\n", pdu_length);
+		if (!is_smb_response(server, buf[0]))
+			continue;
+
+		pending_reconnect = false;
+next_pdu:
+		server->pdu_size = pdu_length;
+
+		/* make sure we have enough to get to the MID */
+		if (server->pdu_size < MID_HEADER_SIZE(server)) {
+			cifs_server_dbg(VFS, "SMB response too short (%u bytes)\n",
+				 server->pdu_size);
+			cifs_reconnect(server, true);
+			continue;
+		}
+
+		/* read down to the MID */
+		length = cifs_read_from_socket(server,
+			     buf + HEADER_PREAMBLE_SIZE(server),
+			     MID_HEADER_SIZE(server));
+		if (length < 0)
+			continue;
+		server->total_read += length;
+
+		if (server->ops->next_header) {
+			if (server->ops->next_header(server, buf, &next_offset)) {
+				cifs_dbg(VFS, "%s: malformed response (next_offset=%u)\n",
+					 __func__, next_offset);
+				cifs_reconnect(server, true);
+				continue;
+			}
+			if (next_offset)
+				server->pdu_size = next_offset;
+		}
+
+		memset(mids, 0, sizeof(mids));
+		memset(bufs, 0, sizeof(bufs));
+		num_mids = 0;
+
+		if (server->ops->is_transform_hdr &&
+		    server->ops->receive_transform &&
+		    server->ops->is_transform_hdr(buf)) {
+			length = server->ops->receive_transform(server,
+								mids,
+								bufs,
+								&num_mids);
+		} else {
+			mids[0] = server->ops->find_mid(server, buf);
+			bufs[0] = buf;
+			num_mids = 1;
+
+			if (!mids[0] || !mids[0]->receive)
+				length = standard_receive3(server, mids[0]);
+			else
+				length = mids[0]->receive(server, mids[0]);
+		}
+
+		if (length < 0) {
+			for (i = 0; i < num_mids; i++)
+				if (mids[i])
+					release_mid(mids[i]);
+			continue;
+		}
+
+		if (server->ops->is_status_io_timeout &&
+		    server->ops->is_status_io_timeout(buf)) {
+			num_io_timeout++;
+			if (num_io_timeout > MAX_STATUS_IO_TIMEOUT) {
+				cifs_server_dbg(VFS,
+						"Number of request timeouts exceeded %d. Reconnecting",
+						MAX_STATUS_IO_TIMEOUT);
+
+				pending_reconnect = true;
+				num_io_timeout = 0;
+			}
+		}
+
+		server->lstrp = jiffies;
+
+		for (i = 0; i < num_mids; i++) {
+			if (mids[i] != NULL) {
+				mids[i]->resp_buf_size = server->pdu_size;
+
+				if (bufs[i] && server->ops->is_network_name_deleted)
+					server->ops->is_network_name_deleted(bufs[i],
+									server);
+
+				if (!mids[i]->multiRsp || mids[i]->multiEnd)
+					mids[i]->callback(mids[i]);
+
+				release_mid(mids[i]);
+			} else if (server->ops->is_oplock_break &&
+				   server->ops->is_oplock_break(bufs[i],
+								server)) {
+				smb2_add_credits_from_hdr(bufs[i], server);
+				cifs_dbg(FYI, "Received oplock break\n");
+			} else {
+				cifs_server_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n",
+						atomic_read(&mid_count));
+				cifs_dump_mem("Received Data is: ", bufs[i],
+					      HEADER_SIZE(server));
+				smb2_add_credits_from_hdr(bufs[i], server);
+#ifdef CONFIG_CIFS_DEBUG2
+				if (server->ops->dump_detail)
+					server->ops->dump_detail(bufs[i],
+								 server);
+				cifs_dump_mids(server);
+#endif /* CIFS_DEBUG2 */
+			}
+		}
+
+		if (pdu_length > server->pdu_size) {
+			if (!allocate_buffers(server))
+				continue;
+			pdu_length -= server->pdu_size;
+			server->total_read = 0;
+			server->large_buf = false;
+			buf = server->smallbuf;
+			goto next_pdu;
+		}
+
+		/* do this reconnect at the very end after processing all MIDs */
+		if (pending_reconnect)
+			cifs_reconnect(server, true);
+
+	} /* end while !EXITING */
+
+	/* buffer usually freed in free_mid - need to free it here on exit */
+	cifs_buf_release(server->bigbuf);
+	if (server->smallbuf) /* no sense logging a debug message if NULL */
+		cifs_small_buf_release(server->smallbuf);
+
+	task_to_wake = xchg(&server->tsk, NULL);
+	clean_demultiplex_info(server);
+
+	/* if server->tsk was NULL then wait for a signal before exiting */
+	if (!task_to_wake) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		while (!signal_pending(current)) {
+			schedule();
+			set_current_state(TASK_INTERRUPTIBLE);
+		}
+		set_current_state(TASK_RUNNING);
+	}
+
+	memalloc_noreclaim_restore(noreclaim_flag);
+	module_put_and_kthread_exit(0);
+}
+
+int
+cifs_ipaddr_cmp(struct sockaddr *srcaddr, struct sockaddr *rhs)
+{
+	struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
+	struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
+	struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
+	struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)rhs;
+
+	switch (srcaddr->sa_family) {
+	case AF_UNSPEC:
+		switch (rhs->sa_family) {
+		case AF_UNSPEC:
+			return 0;
+		case AF_INET:
+		case AF_INET6:
+			return 1;
+		default:
+			return -1;
+		}
+	case AF_INET: {
+		switch (rhs->sa_family) {
+		case AF_UNSPEC:
+			return -1;
+		case AF_INET:
+			return memcmp(saddr4, vaddr4,
+				      sizeof(struct sockaddr_in));
+		case AF_INET6:
+			return 1;
+		default:
+			return -1;
+		}
+	}
+	case AF_INET6: {
+		switch (rhs->sa_family) {
+		case AF_UNSPEC:
+		case AF_INET:
+			return -1;
+		case AF_INET6:
+			return memcmp(saddr6,
+				      vaddr6,
+				      sizeof(struct sockaddr_in6));
+		default:
+			return -1;
+		}
+	}
+	default:
+		return -1; /* don't expect to be here */
+	}
+}
+
+/*
+ * Returns true if srcaddr isn't specified and rhs isn't specified, or
+ * if srcaddr is specified and matches the IP address of the rhs argument
+ */
+bool
+cifs_match_ipaddr(struct sockaddr *srcaddr, struct sockaddr *rhs)
+{
+	switch (srcaddr->sa_family) {
+	case AF_UNSPEC:
+		return (rhs->sa_family == AF_UNSPEC);
+	case AF_INET: {
+		struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
+		struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
+		return (saddr4->sin_addr.s_addr == vaddr4->sin_addr.s_addr);
+	}
+	case AF_INET6: {
+		struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
+		struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)rhs;
+		return ipv6_addr_equal(&saddr6->sin6_addr, &vaddr6->sin6_addr);
+	}
+	default:
+		WARN_ON(1);
+		return false; /* don't expect to be here */
+	}
+}
+
+/*
+ * If no port is specified in addr structure, we try to match with 445 port
+ * and if it fails - with 139 ports. It should be called only if address
+ * families of server and addr are equal.
+ */
+static bool
+match_port(struct TCP_Server_Info *server, struct sockaddr *addr)
+{
+	__be16 port, *sport;
+
+	/* SMBDirect manages its own ports, don't match it here */
+	if (server->rdma)
+		return true;
+
+	switch (addr->sa_family) {
+	case AF_INET:
+		sport = &((struct sockaddr_in *) &server->dstaddr)->sin_port;
+		port = ((struct sockaddr_in *) addr)->sin_port;
+		break;
+	case AF_INET6:
+		sport = &((struct sockaddr_in6 *) &server->dstaddr)->sin6_port;
+		port = ((struct sockaddr_in6 *) addr)->sin6_port;
+		break;
+	default:
+		WARN_ON(1);
+		return false;
+	}
+
+	if (!port) {
+		port = htons(CIFS_PORT);
+		if (port == *sport)
+			return true;
+
+		port = htons(RFC1001_PORT);
+	}
+
+	return port == *sport;
+}
+
+static bool
+match_address(struct TCP_Server_Info *server, struct sockaddr *addr,
+	      struct sockaddr *srcaddr)
+{
+	switch (addr->sa_family) {
+	case AF_INET: {
+		struct sockaddr_in *addr4 = (struct sockaddr_in *)addr;
+		struct sockaddr_in *srv_addr4 =
+					(struct sockaddr_in *)&server->dstaddr;
+
+		if (addr4->sin_addr.s_addr != srv_addr4->sin_addr.s_addr)
+			return false;
+		break;
+	}
+	case AF_INET6: {
+		struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)addr;
+		struct sockaddr_in6 *srv_addr6 =
+					(struct sockaddr_in6 *)&server->dstaddr;
+
+		if (!ipv6_addr_equal(&addr6->sin6_addr,
+				     &srv_addr6->sin6_addr))
+			return false;
+		if (addr6->sin6_scope_id != srv_addr6->sin6_scope_id)
+			return false;
+		break;
+	}
+	default:
+		WARN_ON(1);
+		return false; /* don't expect to be here */
+	}
+
+	if (!cifs_match_ipaddr(srcaddr, (struct sockaddr *)&server->srcaddr))
+		return false;
+
+	return true;
+}
+
+static bool
+match_security(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
+{
+	/*
+	 * The select_sectype function should either return the ctx->sectype
+	 * that was specified, or "Unspecified" if that sectype was not
+	 * compatible with the given NEGOTIATE request.
+	 */
+	if (server->ops->select_sectype(server, ctx->sectype)
+	     == Unspecified)
+		return false;
+
+	/*
+	 * Now check if signing mode is acceptable. No need to check
+	 * global_secflags at this point since if MUST_SIGN is set then
+	 * the server->sign had better be too.
+	 */
+	if (ctx->sign && !server->sign)
+		return false;
+
+	return true;
+}
+
+/* this function must be called with srv_lock held */
+static int match_server(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
+{
+	struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
+
+	lockdep_assert_held(&server->srv_lock);
+
+	if (ctx->nosharesock)
+		return 0;
+
+	/* this server does not share socket */
+	if (server->nosharesock)
+		return 0;
+
+	/* If multidialect negotiation see if existing sessions match one */
+	if (strcmp(ctx->vals->version_string, SMB3ANY_VERSION_STRING) == 0) {
+		if (server->vals->protocol_id < SMB30_PROT_ID)
+			return 0;
+	} else if (strcmp(ctx->vals->version_string,
+		   SMBDEFAULT_VERSION_STRING) == 0) {
+		if (server->vals->protocol_id < SMB21_PROT_ID)
+			return 0;
+	} else if ((server->vals != ctx->vals) || (server->ops != ctx->ops))
+		return 0;
+
+	if (!net_eq(cifs_net_ns(server), current->nsproxy->net_ns))
+		return 0;
+
+	if (strcasecmp(server->hostname, ctx->server_hostname))
+		return 0;
+
+	if (!match_address(server, addr,
+			   (struct sockaddr *)&ctx->srcaddr))
+		return 0;
+
+	if (!match_port(server, addr))
+		return 0;
+
+	if (!match_security(server, ctx))
+		return 0;
+
+	if (server->echo_interval != ctx->echo_interval * HZ)
+		return 0;
+
+	if (server->rdma != ctx->rdma)
+		return 0;
+
+	if (server->ignore_signature != ctx->ignore_signature)
+		return 0;
+
+	if (server->min_offload != ctx->min_offload)
+		return 0;
+
+	return 1;
+}
+
+struct TCP_Server_Info *
+cifs_find_tcp_session(struct smb3_fs_context *ctx)
+{
+	struct TCP_Server_Info *server;
+
+	spin_lock(&cifs_tcp_ses_lock);
+	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
+		spin_lock(&server->srv_lock);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+		/*
+		 * DFS failover implementation in cifs_reconnect() requires unique tcp sessions for
+		 * DFS connections to do failover properly, so avoid sharing them with regular
+		 * shares or even links that may connect to same server but having completely
+		 * different failover targets.
+		 */
+		if (server->is_dfs_conn) {
+			spin_unlock(&server->srv_lock);
+			continue;
+		}
+#endif
+		/*
+		 * Skip ses channels since they're only handled in lower layers
+		 * (e.g. cifs_send_recv).
+		 */
+		if (CIFS_SERVER_IS_CHAN(server) || !match_server(server, ctx)) {
+			spin_unlock(&server->srv_lock);
+			continue;
+		}
+		spin_unlock(&server->srv_lock);
+
+		++server->srv_count;
+		spin_unlock(&cifs_tcp_ses_lock);
+		cifs_dbg(FYI, "Existing tcp session with server found\n");
+		return server;
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+	return NULL;
+}
+
+void
+cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
+{
+	struct task_struct *task;
+
+	spin_lock(&cifs_tcp_ses_lock);
+	if (--server->srv_count > 0) {
+		spin_unlock(&cifs_tcp_ses_lock);
+		return;
+	}
+
+	/* srv_count can never go negative */
+	WARN_ON(server->srv_count < 0);
+
+	put_net(cifs_net_ns(server));
+
+	list_del_init(&server->tcp_ses_list);
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	/* For secondary channels, we pick up ref-count on the primary server */
+	if (CIFS_SERVER_IS_CHAN(server))
+		cifs_put_tcp_session(server->primary_server, from_reconnect);
+
+	cancel_delayed_work_sync(&server->echo);
+	cancel_delayed_work_sync(&server->resolve);
+
+	if (from_reconnect)
+		/*
+		 * Avoid deadlock here: reconnect work calls
+		 * cifs_put_tcp_session() at its end. Need to be sure
+		 * that reconnect work does nothing with server pointer after
+		 * that step.
+		 */
+		cancel_delayed_work(&server->reconnect);
+	else
+		cancel_delayed_work_sync(&server->reconnect);
+
+	spin_lock(&server->srv_lock);
+	server->tcpStatus = CifsExiting;
+	spin_unlock(&server->srv_lock);
+
+	cifs_crypto_secmech_release(server);
+
+	kfree_sensitive(server->session_key.response);
+	server->session_key.response = NULL;
+	server->session_key.len = 0;
+	kfree(server->hostname);
+	server->hostname = NULL;
+
+	task = xchg(&server->tsk, NULL);
+	if (task)
+		send_sig(SIGKILL, task, 1);
+}
+
+struct TCP_Server_Info *
+cifs_get_tcp_session(struct smb3_fs_context *ctx,
+		     struct TCP_Server_Info *primary_server)
+{
+	struct TCP_Server_Info *tcp_ses = NULL;
+	int rc;
+
+	cifs_dbg(FYI, "UNC: %s\n", ctx->UNC);
+
+	/* see if we already have a matching tcp_ses */
+	tcp_ses = cifs_find_tcp_session(ctx);
+	if (tcp_ses)
+		return tcp_ses;
+
+	tcp_ses = kzalloc(sizeof(struct TCP_Server_Info), GFP_KERNEL);
+	if (!tcp_ses) {
+		rc = -ENOMEM;
+		goto out_err;
+	}
+
+	tcp_ses->hostname = kstrdup(ctx->server_hostname, GFP_KERNEL);
+	if (!tcp_ses->hostname) {
+		rc = -ENOMEM;
+		goto out_err;
+	}
+
+	if (ctx->nosharesock)
+		tcp_ses->nosharesock = true;
+
+	tcp_ses->ops = ctx->ops;
+	tcp_ses->vals = ctx->vals;
+	cifs_set_net_ns(tcp_ses, get_net(current->nsproxy->net_ns));
+
+	tcp_ses->conn_id = atomic_inc_return(&tcpSesNextId);
+	tcp_ses->noblockcnt = ctx->rootfs;
+	tcp_ses->noblocksnd = ctx->noblocksnd || ctx->rootfs;
+	tcp_ses->noautotune = ctx->noautotune;
+	tcp_ses->tcp_nodelay = ctx->sockopt_tcp_nodelay;
+	tcp_ses->rdma = ctx->rdma;
+	tcp_ses->in_flight = 0;
+	tcp_ses->max_in_flight = 0;
+	tcp_ses->credits = 1;
+	if (primary_server) {
+		spin_lock(&cifs_tcp_ses_lock);
+		++primary_server->srv_count;
+		spin_unlock(&cifs_tcp_ses_lock);
+		tcp_ses->primary_server = primary_server;
+	}
+	init_waitqueue_head(&tcp_ses->response_q);
+	init_waitqueue_head(&tcp_ses->request_q);
+	INIT_LIST_HEAD(&tcp_ses->pending_mid_q);
+	mutex_init(&tcp_ses->_srv_mutex);
+	memcpy(tcp_ses->workstation_RFC1001_name,
+		ctx->source_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
+	memcpy(tcp_ses->server_RFC1001_name,
+		ctx->target_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
+	tcp_ses->session_estab = false;
+	tcp_ses->sequence_number = 0;
+	tcp_ses->channel_sequence_num = 0; /* only tracked for primary channel */
+	tcp_ses->reconnect_instance = 1;
+	tcp_ses->lstrp = jiffies;
+	tcp_ses->compress_algorithm = cpu_to_le16(ctx->compression);
+	spin_lock_init(&tcp_ses->req_lock);
+	spin_lock_init(&tcp_ses->srv_lock);
+	spin_lock_init(&tcp_ses->mid_lock);
+	INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
+	INIT_LIST_HEAD(&tcp_ses->smb_ses_list);
+	INIT_DELAYED_WORK(&tcp_ses->echo, cifs_echo_request);
+	INIT_DELAYED_WORK(&tcp_ses->resolve, cifs_resolve_server);
+	INIT_DELAYED_WORK(&tcp_ses->reconnect, smb2_reconnect_server);
+	mutex_init(&tcp_ses->reconnect_mutex);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	mutex_init(&tcp_ses->refpath_lock);
+#endif
+	memcpy(&tcp_ses->srcaddr, &ctx->srcaddr,
+	       sizeof(tcp_ses->srcaddr));
+	memcpy(&tcp_ses->dstaddr, &ctx->dstaddr,
+		sizeof(tcp_ses->dstaddr));
+	if (ctx->use_client_guid)
+		memcpy(tcp_ses->client_guid, ctx->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
+	 * no need to spinlock this init of tcpStatus or srv_count
+	 */
+	tcp_ses->tcpStatus = CifsNew;
+	++tcp_ses->srv_count;
+
+	if (ctx->echo_interval >= SMB_ECHO_INTERVAL_MIN &&
+		ctx->echo_interval <= SMB_ECHO_INTERVAL_MAX)
+		tcp_ses->echo_interval = ctx->echo_interval * HZ;
+	else
+		tcp_ses->echo_interval = SMB_ECHO_INTERVAL_DEFAULT * HZ;
+	if (tcp_ses->rdma) {
+#ifndef CONFIG_CIFS_SMB_DIRECT
+		cifs_dbg(VFS, "CONFIG_CIFS_SMB_DIRECT is not enabled\n");
+		rc = -ENOENT;
+		goto out_err_crypto_release;
+#endif
+		tcp_ses->smbd_conn = smbd_get_connection(
+			tcp_ses, (struct sockaddr *)&ctx->dstaddr);
+		if (tcp_ses->smbd_conn) {
+			cifs_dbg(VFS, "RDMA transport established\n");
+			rc = 0;
+			goto smbd_connected;
+		} else {
+			rc = -ENOENT;
+			goto out_err_crypto_release;
+		}
+	}
+	rc = ip_connect(tcp_ses);
+	if (rc < 0) {
+		cifs_dbg(VFS, "Error connecting to socket. Aborting operation.\n");
+		goto out_err_crypto_release;
+	}
+smbd_connected:
+	/*
+	 * since we're in a cifs function already, we know that
+	 * this will succeed. No need for try_module_get().
+	 */
+	__module_get(THIS_MODULE);
+	tcp_ses->tsk = kthread_run(cifs_demultiplex_thread,
+				  tcp_ses, "cifsd");
+	if (IS_ERR(tcp_ses->tsk)) {
+		rc = PTR_ERR(tcp_ses->tsk);
+		cifs_dbg(VFS, "error %d create cifsd thread\n", rc);
+		module_put(THIS_MODULE);
+		goto out_err_crypto_release;
+	}
+	tcp_ses->min_offload = ctx->min_offload;
+	/*
+	 * at this point we are the only ones with the pointer
+	 * to the struct since the kernel thread not created yet
+	 * no need to spinlock this update of tcpStatus
+	 */
+	spin_lock(&tcp_ses->srv_lock);
+	tcp_ses->tcpStatus = CifsNeedNegotiate;
+	spin_unlock(&tcp_ses->srv_lock);
+
+	if ((ctx->max_credits < 20) || (ctx->max_credits > 60000))
+		tcp_ses->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
+	else
+		tcp_ses->max_credits = ctx->max_credits;
+
+	tcp_ses->nr_targets = 1;
+	tcp_ses->ignore_signature = ctx->ignore_signature;
+	/* thread spawned, put it on the list */
+	spin_lock(&cifs_tcp_ses_lock);
+	list_add(&tcp_ses->tcp_ses_list, &cifs_tcp_ses_list);
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	/* queue echo request delayed work */
+	queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
+
+	/* queue dns resolution delayed work */
+	cifs_dbg(FYI, "%s: next dns resolution scheduled for %d seconds in the future\n",
+		 __func__, SMB_DNS_RESOLVE_INTERVAL_DEFAULT);
+
+	queue_delayed_work(cifsiod_wq, &tcp_ses->resolve, (SMB_DNS_RESOLVE_INTERVAL_DEFAULT * HZ));
+
+	return tcp_ses;
+
+out_err_crypto_release:
+	cifs_crypto_secmech_release(tcp_ses);
+
+	put_net(cifs_net_ns(tcp_ses));
+
+out_err:
+	if (tcp_ses) {
+		if (CIFS_SERVER_IS_CHAN(tcp_ses))
+			cifs_put_tcp_session(tcp_ses->primary_server, false);
+		kfree(tcp_ses->hostname);
+		if (tcp_ses->ssocket)
+			sock_release(tcp_ses->ssocket);
+		kfree(tcp_ses);
+	}
+	return ERR_PTR(rc);
+}
+
+/* this function must be called with ses_lock and chan_lock held */
+static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
+{
+	if (ctx->sectype != Unspecified &&
+	    ctx->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 < ctx->max_channels)
+		return 0;
+
+	switch (ses->sectype) {
+	case Kerberos:
+		if (!uid_eq(ctx->cred_uid, ses->cred_uid))
+			return 0;
+		break;
+	default:
+		/* NULL username means anonymous session */
+		if (ses->user_name == NULL) {
+			if (!ctx->nullauth)
+				return 0;
+			break;
+		}
+
+		/* anything else takes username/password */
+		if (strncmp(ses->user_name,
+			    ctx->username ? ctx->username : "",
+			    CIFS_MAX_USERNAME_LEN))
+			return 0;
+		if ((ctx->username && strlen(ctx->username) != 0) &&
+		    ses->password != NULL &&
+		    strncmp(ses->password,
+			    ctx->password ? ctx->password : "",
+			    CIFS_MAX_PASSWORD_LEN))
+			return 0;
+	}
+	return 1;
+}
+
+/**
+ * cifs_setup_ipc - helper to setup the IPC tcon for the session
+ * @ses: smb session to issue the request on
+ * @ctx: the superblock configuration context to use for building the
+ *       new tree connection for the IPC (interprocess communication RPC)
+ *
+ * A new IPC connection is made and stored in the session
+ * tcon_ipc. The IPC tcon has the same lifetime as the session.
+ */
+static int
+cifs_setup_ipc(struct cifs_ses *ses, struct smb3_fs_context *ctx)
+{
+	int rc = 0, xid;
+	struct cifs_tcon *tcon;
+	char unc[SERVER_NAME_LENGTH + sizeof("//x/IPC$")] = {0};
+	bool seal = false;
+	struct TCP_Server_Info *server = ses->server;
+
+	/*
+	 * If the mount request that resulted in the creation of the
+	 * session requires encryption, force IPC to be encrypted too.
+	 */
+	if (ctx->seal) {
+		if (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION)
+			seal = true;
+		else {
+			cifs_server_dbg(VFS,
+				 "IPC: server doesn't support encryption\n");
+			return -EOPNOTSUPP;
+		}
+	}
+
+	tcon = tconInfoAlloc();
+	if (tcon == NULL)
+		return -ENOMEM;
+
+	spin_lock(&server->srv_lock);
+	scnprintf(unc, sizeof(unc), "\\\\%s\\IPC$", server->hostname);
+	spin_unlock(&server->srv_lock);
+
+	xid = get_xid();
+	tcon->ses = ses;
+	tcon->ipc = true;
+	tcon->seal = seal;
+	rc = server->ops->tree_connect(xid, ses, unc, tcon, ctx->local_nls);
+	free_xid(xid);
+
+	if (rc) {
+		cifs_server_dbg(VFS, "failed to connect to IPC (rc=%d)\n", rc);
+		tconInfoFree(tcon);
+		goto out;
+	}
+
+	cifs_dbg(FYI, "IPC tcon rc=%d ipc tid=0x%x\n", rc, tcon->tid);
+
+	spin_lock(&tcon->tc_lock);
+	tcon->status = TID_GOOD;
+	spin_unlock(&tcon->tc_lock);
+	ses->tcon_ipc = tcon;
+out:
+	return rc;
+}
+
+/**
+ * cifs_free_ipc - helper to release the session IPC tcon
+ * @ses: smb session to unmount the IPC from
+ *
+ * Needs to be called everytime a session is destroyed.
+ *
+ * On session close, the IPC is closed and the server must release all tcons of the session.
+ * No need to send a tree disconnect here.
+ *
+ * Besides, it will make the server to not close durable and resilient files on session close, as
+ * specified in MS-SMB2 3.3.5.6 Receiving an SMB2 LOGOFF Request.
+ */
+static int
+cifs_free_ipc(struct cifs_ses *ses)
+{
+	struct cifs_tcon *tcon = ses->tcon_ipc;
+
+	if (tcon == NULL)
+		return 0;
+
+	tconInfoFree(tcon);
+	ses->tcon_ipc = NULL;
+	return 0;
+}
+
+static struct cifs_ses *
+cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
+{
+	struct cifs_ses *ses;
+
+	spin_lock(&cifs_tcp_ses_lock);
+	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+		spin_lock(&ses->ses_lock);
+		if (ses->ses_status == SES_EXITING) {
+			spin_unlock(&ses->ses_lock);
+			continue;
+		}
+		spin_lock(&ses->chan_lock);
+		if (!match_session(ses, ctx)) {
+			spin_unlock(&ses->chan_lock);
+			spin_unlock(&ses->ses_lock);
+			continue;
+		}
+		spin_unlock(&ses->chan_lock);
+		spin_unlock(&ses->ses_lock);
+
+		++ses->ses_count;
+		spin_unlock(&cifs_tcp_ses_lock);
+		return ses;
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+	return NULL;
+}
+
+void cifs_put_smb_ses(struct cifs_ses *ses)
+{
+	unsigned int rc, xid;
+	unsigned int chan_count;
+	struct TCP_Server_Info *server = ses->server;
+
+	spin_lock(&ses->ses_lock);
+	if (ses->ses_status == SES_EXITING) {
+		spin_unlock(&ses->ses_lock);
+		return;
+	}
+	spin_unlock(&ses->ses_lock);
+
+	cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
+	cifs_dbg(FYI,
+		 "%s: ses ipc: %s\n", __func__, ses->tcon_ipc ? ses->tcon_ipc->tree_name : "NONE");
+
+	spin_lock(&cifs_tcp_ses_lock);
+	if (--ses->ses_count > 0) {
+		spin_unlock(&cifs_tcp_ses_lock);
+		return;
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	/* ses_count can never go negative */
+	WARN_ON(ses->ses_count < 0);
+
+	if (ses->ses_status == SES_GOOD)
+		ses->ses_status = SES_EXITING;
+
+	cifs_free_ipc(ses);
+
+	if (ses->ses_status == SES_EXITING && server->ops->logoff) {
+		xid = get_xid();
+		rc = server->ops->logoff(xid, ses);
+		if (rc)
+			cifs_server_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
+				__func__, rc);
+		_free_xid(xid);
+	}
+
+	spin_lock(&cifs_tcp_ses_lock);
+	list_del_init(&ses->smb_ses_list);
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	chan_count = ses->chan_count;
+
+	/* close any extra channels */
+	if (chan_count > 1) {
+		int i;
+
+		for (i = 1; i < chan_count; i++) {
+			if (ses->chans[i].iface) {
+				kref_put(&ses->chans[i].iface->refcount, release_iface);
+				ses->chans[i].iface = NULL;
+			}
+			cifs_put_tcp_session(ses->chans[i].server, 0);
+			ses->chans[i].server = NULL;
+		}
+	}
+
+	/* we now account for primary channel in iface->refcount */
+	if (ses->chans[0].iface) {
+		kref_put(&ses->chans[0].iface->refcount, release_iface);
+		ses->chans[0].server = NULL;
+	}
+
+	sesInfoFree(ses);
+	cifs_put_tcp_session(server, 0);
+}
+
+#ifdef CONFIG_KEYS
+
+/* strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1 */
+#define CIFSCREDS_DESC_SIZE (7 + CIFS_MAX_DOMAINNAME_LEN + 1)
+
+/* Populate username and pw fields from keyring if possible */
+static int
+cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
+{
+	int rc = 0;
+	int is_domain = 0;
+	const char *delim, *payload;
+	char *desc;
+	ssize_t len;
+	struct key *key;
+	struct TCP_Server_Info *server = ses->server;
+	struct sockaddr_in *sa;
+	struct sockaddr_in6 *sa6;
+	const struct user_key_payload *upayload;
+
+	desc = kmalloc(CIFSCREDS_DESC_SIZE, GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+
+	/* try to find an address key first */
+	switch (server->dstaddr.ss_family) {
+	case AF_INET:
+		sa = (struct sockaddr_in *)&server->dstaddr;
+		sprintf(desc, "cifs:a:%pI4", &sa->sin_addr.s_addr);
+		break;
+	case AF_INET6:
+		sa6 = (struct sockaddr_in6 *)&server->dstaddr;
+		sprintf(desc, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
+		break;
+	default:
+		cifs_dbg(FYI, "Bad ss_family (%hu)\n",
+			 server->dstaddr.ss_family);
+		rc = -EINVAL;
+		goto out_err;
+	}
+
+	cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
+	key = request_key(&key_type_logon, desc, "");
+	if (IS_ERR(key)) {
+		if (!ses->domainName) {
+			cifs_dbg(FYI, "domainName is NULL\n");
+			rc = PTR_ERR(key);
+			goto out_err;
+		}
+
+		/* didn't work, try to find a domain key */
+		sprintf(desc, "cifs:d:%s", ses->domainName);
+		cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
+		key = request_key(&key_type_logon, desc, "");
+		if (IS_ERR(key)) {
+			rc = PTR_ERR(key);
+			goto out_err;
+		}
+		is_domain = 1;
+	}
+
+	down_read(&key->sem);
+	upayload = user_key_payload_locked(key);
+	if (IS_ERR_OR_NULL(upayload)) {
+		rc = upayload ? PTR_ERR(upayload) : -EINVAL;
+		goto out_key_put;
+	}
+
+	/* find first : in payload */
+	payload = upayload->data;
+	delim = strnchr(payload, upayload->datalen, ':');
+	cifs_dbg(FYI, "payload=%s\n", payload);
+	if (!delim) {
+		cifs_dbg(FYI, "Unable to find ':' in payload (datalen=%d)\n",
+			 upayload->datalen);
+		rc = -EINVAL;
+		goto out_key_put;
+	}
+
+	len = delim - payload;
+	if (len > CIFS_MAX_USERNAME_LEN || len <= 0) {
+		cifs_dbg(FYI, "Bad value from username search (len=%zd)\n",
+			 len);
+		rc = -EINVAL;
+		goto out_key_put;
+	}
+
+	ctx->username = kstrndup(payload, len, GFP_KERNEL);
+	if (!ctx->username) {
+		cifs_dbg(FYI, "Unable to allocate %zd bytes for username\n",
+			 len);
+		rc = -ENOMEM;
+		goto out_key_put;
+	}
+	cifs_dbg(FYI, "%s: username=%s\n", __func__, ctx->username);
+
+	len = key->datalen - (len + 1);
+	if (len > CIFS_MAX_PASSWORD_LEN || len <= 0) {
+		cifs_dbg(FYI, "Bad len for password search (len=%zd)\n", len);
+		rc = -EINVAL;
+		kfree(ctx->username);
+		ctx->username = NULL;
+		goto out_key_put;
+	}
+
+	++delim;
+	ctx->password = kstrndup(delim, len, GFP_KERNEL);
+	if (!ctx->password) {
+		cifs_dbg(FYI, "Unable to allocate %zd bytes for password\n",
+			 len);
+		rc = -ENOMEM;
+		kfree(ctx->username);
+		ctx->username = NULL;
+		goto out_key_put;
+	}
+
+	/*
+	 * If we have a domain key then we must set the domainName in the
+	 * for the request.
+	 */
+	if (is_domain && ses->domainName) {
+		ctx->domainname = kstrdup(ses->domainName, GFP_KERNEL);
+		if (!ctx->domainname) {
+			cifs_dbg(FYI, "Unable to allocate %zd bytes for domain\n",
+				 len);
+			rc = -ENOMEM;
+			kfree(ctx->username);
+			ctx->username = NULL;
+			kfree_sensitive(ctx->password);
+			ctx->password = NULL;
+			goto out_key_put;
+		}
+	}
+
+	strscpy(ctx->workstation_name, ses->workstation_name, sizeof(ctx->workstation_name));
+
+out_key_put:
+	up_read(&key->sem);
+	key_put(key);
+out_err:
+	kfree(desc);
+	cifs_dbg(FYI, "%s: returning %d\n", __func__, rc);
+	return rc;
+}
+#else /* ! CONFIG_KEYS */
+static inline int
+cifs_set_cifscreds(struct smb3_fs_context *ctx __attribute__((unused)),
+		   struct cifs_ses *ses __attribute__((unused)))
+{
+	return -ENOSYS;
+}
+#endif /* CONFIG_KEYS */
+
+/**
+ * cifs_get_smb_ses - get a session matching @ctx data from @server
+ * @server: server to setup the session to
+ * @ctx: superblock configuration context to use to setup the session
+ *
+ * This function assumes it is being called from cifs_mount() where we
+ * already got a server reference (server refcount +1). See
+ * cifs_get_tcon() for refcount explanations.
+ */
+struct cifs_ses *
+cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
+{
+	int rc = 0;
+	unsigned int xid;
+	struct cifs_ses *ses;
+	struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
+	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
+
+	xid = get_xid();
+
+	ses = cifs_find_smb_ses(server, ctx);
+	if (ses) {
+		cifs_dbg(FYI, "Existing smb sess found (status=%d)\n",
+			 ses->ses_status);
+
+		spin_lock(&ses->chan_lock);
+		if (cifs_chan_needs_reconnect(ses, server)) {
+			spin_unlock(&ses->chan_lock);
+			cifs_dbg(FYI, "Session needs reconnect\n");
+
+			mutex_lock(&ses->session_mutex);
+			rc = cifs_negotiate_protocol(xid, ses, server);
+			if (rc) {
+				mutex_unlock(&ses->session_mutex);
+				/* problem -- put our ses reference */
+				cifs_put_smb_ses(ses);
+				free_xid(xid);
+				return ERR_PTR(rc);
+			}
+
+			rc = cifs_setup_session(xid, ses, server,
+						ctx->local_nls);
+			if (rc) {
+				mutex_unlock(&ses->session_mutex);
+				/* problem -- put our reference */
+				cifs_put_smb_ses(ses);
+				free_xid(xid);
+				return ERR_PTR(rc);
+			}
+			mutex_unlock(&ses->session_mutex);
+
+			spin_lock(&ses->chan_lock);
+		}
+		spin_unlock(&ses->chan_lock);
+
+		/* existing SMB ses has a server reference already */
+		cifs_put_tcp_session(server, 0);
+		free_xid(xid);
+		return ses;
+	}
+
+	rc = -ENOMEM;
+
+	cifs_dbg(FYI, "Existing smb sess not found\n");
+	ses = sesInfoAlloc();
+	if (ses == NULL)
+		goto get_ses_fail;
+
+	/* new SMB session uses our server ref */
+	ses->server = server;
+	if (server->dstaddr.ss_family == AF_INET6)
+		sprintf(ses->ip_addr, "%pI6", &addr6->sin6_addr);
+	else
+		sprintf(ses->ip_addr, "%pI4", &addr->sin_addr);
+
+	if (ctx->username) {
+		ses->user_name = kstrdup(ctx->username, GFP_KERNEL);
+		if (!ses->user_name)
+			goto get_ses_fail;
+	}
+
+	/* ctx->password freed at unmount */
+	if (ctx->password) {
+		ses->password = kstrdup(ctx->password, GFP_KERNEL);
+		if (!ses->password)
+			goto get_ses_fail;
+	}
+	if (ctx->domainname) {
+		ses->domainName = kstrdup(ctx->domainname, GFP_KERNEL);
+		if (!ses->domainName)
+			goto get_ses_fail;
+	}
+
+	strscpy(ses->workstation_name, ctx->workstation_name, sizeof(ses->workstation_name));
+
+	if (ctx->domainauto)
+		ses->domainAuto = ctx->domainauto;
+	ses->cred_uid = ctx->cred_uid;
+	ses->linux_uid = ctx->linux_uid;
+
+	ses->sectype = ctx->sectype;
+	ses->sign = ctx->sign;
+
+	/* add server as first channel */
+	spin_lock(&ses->chan_lock);
+	ses->chans[0].server = server;
+	ses->chan_count = 1;
+	ses->chan_max = ctx->multichannel ? ctx->max_channels:1;
+	ses->chans_need_reconnect = 1;
+	spin_unlock(&ses->chan_lock);
+
+	mutex_lock(&ses->session_mutex);
+	rc = cifs_negotiate_protocol(xid, ses, server);
+	if (!rc)
+		rc = cifs_setup_session(xid, ses, server, ctx->local_nls);
+	mutex_unlock(&ses->session_mutex);
+
+	/* each channel uses a different signing key */
+	spin_lock(&ses->chan_lock);
+	memcpy(ses->chans[0].signkey, ses->smb3signingkey,
+	       sizeof(ses->smb3signingkey));
+	spin_unlock(&ses->chan_lock);
+
+	if (rc)
+		goto get_ses_fail;
+
+	/*
+	 * success, put it on the list and add it as first channel
+	 * note: the session becomes active soon after this. So you'll
+	 * need to lock before changing something in the session.
+	 */
+	spin_lock(&cifs_tcp_ses_lock);
+	list_add(&ses->smb_ses_list, &server->smb_ses_list);
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	cifs_setup_ipc(ses, ctx);
+
+	free_xid(xid);
+
+	return ses;
+
+get_ses_fail:
+	sesInfoFree(ses);
+	free_xid(xid);
+	return ERR_PTR(rc);
+}
+
+/* this function must be called with tc_lock held */
+static int match_tcon(struct cifs_tcon *tcon, struct smb3_fs_context *ctx)
+{
+	if (tcon->status == TID_EXITING)
+		return 0;
+	if (strncmp(tcon->tree_name, ctx->UNC, MAX_TREE_SIZE))
+		return 0;
+	if (tcon->seal != ctx->seal)
+		return 0;
+	if (tcon->snapshot_time != ctx->snapshot_time)
+		return 0;
+	if (tcon->handle_timeout != ctx->handle_timeout)
+		return 0;
+	if (tcon->no_lease != ctx->no_lease)
+		return 0;
+	if (tcon->nodelete != ctx->nodelete)
+		return 0;
+	return 1;
+}
+
+static struct cifs_tcon *
+cifs_find_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
+{
+	struct cifs_tcon *tcon;
+
+	spin_lock(&cifs_tcp_ses_lock);
+	list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
+		spin_lock(&tcon->tc_lock);
+		if (!match_tcon(tcon, ctx)) {
+			spin_unlock(&tcon->tc_lock);
+			continue;
+		}
+		++tcon->tc_count;
+		spin_unlock(&tcon->tc_lock);
+		spin_unlock(&cifs_tcp_ses_lock);
+		return tcon;
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+	return NULL;
+}
+
+void
+cifs_put_tcon(struct cifs_tcon *tcon)
+{
+	unsigned int xid;
+	struct cifs_ses *ses;
+
+	/*
+	 * IPC tcon share the lifetime of their session and are
+	 * destroyed in the session put function
+	 */
+	if (tcon == NULL || tcon->ipc)
+		return;
+
+	ses = tcon->ses;
+	cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
+	spin_lock(&cifs_tcp_ses_lock);
+	spin_lock(&tcon->tc_lock);
+	if (--tcon->tc_count > 0) {
+		spin_unlock(&tcon->tc_lock);
+		spin_unlock(&cifs_tcp_ses_lock);
+		return;
+	}
+
+	/* tc_count can never go negative */
+	WARN_ON(tcon->tc_count < 0);
+
+	list_del_init(&tcon->tcon_list);
+	tcon->status = TID_EXITING;
+	spin_unlock(&tcon->tc_lock);
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	/* cancel polling of interfaces */
+	cancel_delayed_work_sync(&tcon->query_interfaces);
+
+	if (tcon->use_witness) {
+		int rc;
+
+		rc = cifs_swn_unregister(tcon);
+		if (rc < 0) {
+			cifs_dbg(VFS, "%s: Failed to unregister for witness notifications: %d\n",
+					__func__, rc);
+		}
+	}
+
+	xid = get_xid();
+	if (ses->server->ops->tree_disconnect)
+		ses->server->ops->tree_disconnect(xid, tcon);
+	_free_xid(xid);
+
+	cifs_fscache_release_super_cookie(tcon);
+	tconInfoFree(tcon);
+	cifs_put_smb_ses(ses);
+}
+
+/**
+ * cifs_get_tcon - get a tcon matching @ctx data from @ses
+ * @ses: smb session to issue the request on
+ * @ctx: the superblock configuration context to use for building the
+ *
+ * - tcon refcount is the number of mount points using the tcon.
+ * - ses refcount is the number of tcon using the session.
+ *
+ * 1. This function assumes it is being called from cifs_mount() where
+ *    we already got a session reference (ses refcount +1).
+ *
+ * 2. Since we're in the context of adding a mount point, the end
+ *    result should be either:
+ *
+ * a) a new tcon already allocated with refcount=1 (1 mount point) and
+ *    its session refcount incremented (1 new tcon). This +1 was
+ *    already done in (1).
+ *
+ * b) an existing tcon with refcount+1 (add a mount point to it) and
+ *    identical ses refcount (no new tcon). Because of (1) we need to
+ *    decrement the ses refcount.
+ */
+static struct cifs_tcon *
+cifs_get_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
+{
+	int rc, xid;
+	struct cifs_tcon *tcon;
+
+	tcon = cifs_find_tcon(ses, ctx);
+	if (tcon) {
+		/*
+		 * tcon has refcount already incremented but we need to
+		 * decrement extra ses reference gotten by caller (case b)
+		 */
+		cifs_dbg(FYI, "Found match on UNC path\n");
+		cifs_put_smb_ses(ses);
+		return tcon;
+	}
+
+	if (!ses->server->ops->tree_connect) {
+		rc = -ENOSYS;
+		goto out_fail;
+	}
+
+	tcon = tconInfoAlloc();
+	if (tcon == NULL) {
+		rc = -ENOMEM;
+		goto out_fail;
+	}
+
+	if (ctx->snapshot_time) {
+		if (ses->server->vals->protocol_id == 0) {
+			cifs_dbg(VFS,
+			     "Use SMB2 or later for snapshot mount option\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		} else
+			tcon->snapshot_time = ctx->snapshot_time;
+	}
+
+	if (ctx->handle_timeout) {
+		if (ses->server->vals->protocol_id == 0) {
+			cifs_dbg(VFS,
+			     "Use SMB2.1 or later for handle timeout option\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		} else
+			tcon->handle_timeout = ctx->handle_timeout;
+	}
+
+	tcon->ses = ses;
+	if (ctx->password) {
+		tcon->password = kstrdup(ctx->password, GFP_KERNEL);
+		if (!tcon->password) {
+			rc = -ENOMEM;
+			goto out_fail;
+		}
+	}
+
+	if (ctx->seal) {
+		if (ses->server->vals->protocol_id == 0) {
+			cifs_dbg(VFS,
+				 "SMB3 or later required for encryption\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		} else if (tcon->ses->server->capabilities &
+					SMB2_GLOBAL_CAP_ENCRYPTION)
+			tcon->seal = true;
+		else {
+			cifs_dbg(VFS, "Encryption is not supported on share\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		}
+	}
+
+	if (ctx->linux_ext) {
+		if (ses->server->posix_ext_supported) {
+			tcon->posix_extensions = true;
+			pr_warn_once("SMB3.11 POSIX Extensions are experimental\n");
+		} else if ((ses->server->vals->protocol_id == SMB311_PROT_ID) ||
+		    (strcmp(ses->server->vals->version_string,
+		     SMB3ANY_VERSION_STRING) == 0) ||
+		    (strcmp(ses->server->vals->version_string,
+		     SMBDEFAULT_VERSION_STRING) == 0)) {
+			cifs_dbg(VFS, "Server does not support mounting with posix SMB3.11 extensions\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		} else {
+			cifs_dbg(VFS, "Check vers= mount option. SMB3.11 "
+				"disabled but required for POSIX extensions\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		}
+	}
+
+	xid = get_xid();
+	rc = ses->server->ops->tree_connect(xid, ses, ctx->UNC, tcon,
+					    ctx->local_nls);
+	free_xid(xid);
+	cifs_dbg(FYI, "Tcon rc = %d\n", rc);
+	if (rc)
+		goto out_fail;
+
+	tcon->use_persistent = false;
+	/* check if SMB2 or later, CIFS does not support persistent handles */
+	if (ctx->persistent) {
+		if (ses->server->vals->protocol_id == 0) {
+			cifs_dbg(VFS,
+			     "SMB3 or later required for persistent handles\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		} else if (ses->server->capabilities &
+			   SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
+			tcon->use_persistent = true;
+		else /* persistent handles requested but not supported */ {
+			cifs_dbg(VFS,
+				"Persistent handles not supported on share\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		}
+	} else if ((tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
+	     && (ses->server->capabilities & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
+	     && (ctx->nopersistent == false)) {
+		cifs_dbg(FYI, "enabling persistent handles\n");
+		tcon->use_persistent = true;
+	} else if (ctx->resilient) {
+		if (ses->server->vals->protocol_id == 0) {
+			cifs_dbg(VFS,
+			     "SMB2.1 or later required for resilient handles\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		}
+		tcon->use_resilient = true;
+	}
+
+	tcon->use_witness = false;
+	if (IS_ENABLED(CONFIG_CIFS_SWN_UPCALL) && ctx->witness) {
+		if (ses->server->vals->protocol_id >= SMB30_PROT_ID) {
+			if (tcon->capabilities & SMB2_SHARE_CAP_CLUSTER) {
+				/*
+				 * Set witness in use flag in first place
+				 * to retry registration in the echo task
+				 */
+				tcon->use_witness = true;
+				/* And try to register immediately */
+				rc = cifs_swn_register(tcon);
+				if (rc < 0) {
+					cifs_dbg(VFS, "Failed to register for witness notifications: %d\n", rc);
+					goto out_fail;
+				}
+			} else {
+				/* TODO: try to extend for non-cluster uses (eg multichannel) */
+				cifs_dbg(VFS, "witness requested on mount but no CLUSTER capability on share\n");
+				rc = -EOPNOTSUPP;
+				goto out_fail;
+			}
+		} else {
+			cifs_dbg(VFS, "SMB3 or later required for witness option\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		}
+	}
+
+	/* If the user really knows what they are doing they can override */
+	if (tcon->share_flags & SMB2_SHAREFLAG_NO_CACHING) {
+		if (ctx->cache_ro)
+			cifs_dbg(VFS, "cache=ro requested on mount but NO_CACHING flag set on share\n");
+		else if (ctx->cache_rw)
+			cifs_dbg(VFS, "cache=singleclient requested on mount but NO_CACHING flag set on share\n");
+	}
+
+	if (ctx->no_lease) {
+		if (ses->server->vals->protocol_id == 0) {
+			cifs_dbg(VFS,
+				"SMB2 or later required for nolease option\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
+		} else
+			tcon->no_lease = ctx->no_lease;
+	}
+
+	/*
+	 * We can have only one retry value for a connection to a share so for
+	 * resources mounted more than once to the same server share the last
+	 * value passed in for the retry flag is used.
+	 */
+	tcon->retry = ctx->retry;
+	tcon->nocase = ctx->nocase;
+	tcon->broken_sparse_sup = ctx->no_sparse;
+	if (ses->server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING)
+		tcon->nohandlecache = ctx->nohandlecache;
+	else
+		tcon->nohandlecache = true;
+	tcon->nodelete = ctx->nodelete;
+	tcon->local_lease = ctx->local_lease;
+	INIT_LIST_HEAD(&tcon->pending_opens);
+	tcon->status = TID_GOOD;
+
+	INIT_DELAYED_WORK(&tcon->query_interfaces,
+			  smb2_query_server_interfaces);
+	if (ses->server->dialect >= SMB30_PROT_ID &&
+	    (ses->server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) {
+		/* schedule query interfaces poll */
+		queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
+				   (SMB_INTERFACE_POLL_INTERVAL * HZ));
+	}
+
+	spin_lock(&cifs_tcp_ses_lock);
+	list_add(&tcon->tcon_list, &ses->tcon_list);
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	return tcon;
+
+out_fail:
+	tconInfoFree(tcon);
+	return ERR_PTR(rc);
+}
+
+void
+cifs_put_tlink(struct tcon_link *tlink)
+{
+	if (!tlink || IS_ERR(tlink))
+		return;
+
+	if (!atomic_dec_and_test(&tlink->tl_count) ||
+	    test_bit(TCON_LINK_IN_TREE, &tlink->tl_flags)) {
+		tlink->tl_time = jiffies;
+		return;
+	}
+
+	if (!IS_ERR(tlink_tcon(tlink)))
+		cifs_put_tcon(tlink_tcon(tlink));
+	kfree(tlink);
+	return;
+}
+
+static int
+compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
+{
+	struct cifs_sb_info *old = CIFS_SB(sb);
+	struct cifs_sb_info *new = mnt_data->cifs_sb;
+	unsigned int oldflags = old->mnt_cifs_flags & CIFS_MOUNT_MASK;
+	unsigned int newflags = new->mnt_cifs_flags & CIFS_MOUNT_MASK;
+
+	if ((sb->s_flags & CIFS_MS_MASK) != (mnt_data->flags & CIFS_MS_MASK))
+		return 0;
+
+	if (old->mnt_cifs_serverino_autodisabled)
+		newflags &= ~CIFS_MOUNT_SERVER_INUM;
+
+	if (oldflags != newflags)
+		return 0;
+
+	/*
+	 * We want to share sb only if we don't specify an r/wsize or
+	 * specified r/wsize is greater than or equal to existing one.
+	 */
+	if (new->ctx->wsize && new->ctx->wsize < old->ctx->wsize)
+		return 0;
+
+	if (new->ctx->rsize && new->ctx->rsize < old->ctx->rsize)
+		return 0;
+
+	if (!uid_eq(old->ctx->linux_uid, new->ctx->linux_uid) ||
+	    !gid_eq(old->ctx->linux_gid, new->ctx->linux_gid))
+		return 0;
+
+	if (old->ctx->file_mode != new->ctx->file_mode ||
+	    old->ctx->dir_mode != new->ctx->dir_mode)
+		return 0;
+
+	if (strcmp(old->local_nls->charset, new->local_nls->charset))
+		return 0;
+
+	if (old->ctx->acregmax != new->ctx->acregmax)
+		return 0;
+	if (old->ctx->acdirmax != new->ctx->acdirmax)
+		return 0;
+	if (old->ctx->closetimeo != new->ctx->closetimeo)
+		return 0;
+
+	return 1;
+}
+
+static int
+match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data)
+{
+	struct cifs_sb_info *old = CIFS_SB(sb);
+	struct cifs_sb_info *new = mnt_data->cifs_sb;
+	bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
+		old->prepath;
+	bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
+		new->prepath;
+
+	if (old_set && new_set && !strcmp(new->prepath, old->prepath))
+		return 1;
+	else if (!old_set && !new_set)
+		return 1;
+
+	return 0;
+}
+
+int
+cifs_match_super(struct super_block *sb, void *data)
+{
+	struct cifs_mnt_data *mnt_data = data;
+	struct smb3_fs_context *ctx;
+	struct cifs_sb_info *cifs_sb;
+	struct TCP_Server_Info *tcp_srv;
+	struct cifs_ses *ses;
+	struct cifs_tcon *tcon;
+	struct tcon_link *tlink;
+	int rc = 0;
+
+	spin_lock(&cifs_tcp_ses_lock);
+	cifs_sb = CIFS_SB(sb);
+
+	/* We do not want to use a superblock that has been shutdown */
+	if (CIFS_MOUNT_SHUTDOWN & cifs_sb->mnt_cifs_flags) {
+		spin_unlock(&cifs_tcp_ses_lock);
+		return 0;
+	}
+
+	tlink = cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
+	if (tlink == NULL) {
+		/* can not match superblock if tlink were ever null */
+		spin_unlock(&cifs_tcp_ses_lock);
+		return 0;
+	}
+	tcon = tlink_tcon(tlink);
+	ses = tcon->ses;
+	tcp_srv = ses->server;
+
+	ctx = mnt_data->ctx;
+
+	spin_lock(&tcp_srv->srv_lock);
+	spin_lock(&ses->ses_lock);
+	spin_lock(&ses->chan_lock);
+	spin_lock(&tcon->tc_lock);
+	if (!match_server(tcp_srv, ctx) ||
+	    !match_session(ses, ctx) ||
+	    !match_tcon(tcon, ctx) ||
+	    !match_prepath(sb, mnt_data)) {
+		rc = 0;
+		goto out;
+	}
+
+	rc = compare_mount_options(sb, mnt_data);
+out:
+	spin_unlock(&tcon->tc_lock);
+	spin_unlock(&ses->chan_lock);
+	spin_unlock(&ses->ses_lock);
+	spin_unlock(&tcp_srv->srv_lock);
+
+	spin_unlock(&cifs_tcp_ses_lock);
+	cifs_put_tlink(tlink);
+	return rc;
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+static struct lock_class_key cifs_key[2];
+static struct lock_class_key cifs_slock_key[2];
+
+static inline void
+cifs_reclassify_socket4(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	BUG_ON(!sock_allow_reclassification(sk));
+	sock_lock_init_class_and_name(sk, "slock-AF_INET-CIFS",
+		&cifs_slock_key[0], "sk_lock-AF_INET-CIFS", &cifs_key[0]);
+}
+
+static inline void
+cifs_reclassify_socket6(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	BUG_ON(!sock_allow_reclassification(sk));
+	sock_lock_init_class_and_name(sk, "slock-AF_INET6-CIFS",
+		&cifs_slock_key[1], "sk_lock-AF_INET6-CIFS", &cifs_key[1]);
+}
+#else
+static inline void
+cifs_reclassify_socket4(struct socket *sock)
+{
+}
+
+static inline void
+cifs_reclassify_socket6(struct socket *sock)
+{
+}
+#endif
+
+/* See RFC1001 section 14 on representation of Netbios names */
+static void rfc1002mangle(char *target, char *source, unsigned int length)
+{
+	unsigned int i, j;
+
+	for (i = 0, j = 0; i < (length); i++) {
+		/* mask a nibble at a time and encode */
+		target[j] = 'A' + (0x0F & (source[i] >> 4));
+		target[j+1] = 'A' + (0x0F & source[i]);
+		j += 2;
+	}
+
+}
+
+static int
+bind_socket(struct TCP_Server_Info *server)
+{
+	int rc = 0;
+	if (server->srcaddr.ss_family != AF_UNSPEC) {
+		/* Bind to the specified local IP address */
+		struct socket *socket = server->ssocket;
+		rc = kernel_bind(socket,
+				 (struct sockaddr *) &server->srcaddr,
+				 sizeof(server->srcaddr));
+		if (rc < 0) {
+			struct sockaddr_in *saddr4;
+			struct sockaddr_in6 *saddr6;
+			saddr4 = (struct sockaddr_in *)&server->srcaddr;
+			saddr6 = (struct sockaddr_in6 *)&server->srcaddr;
+			if (saddr6->sin6_family == AF_INET6)
+				cifs_server_dbg(VFS, "Failed to bind to: %pI6c, error: %d\n",
+					 &saddr6->sin6_addr, rc);
+			else
+				cifs_server_dbg(VFS, "Failed to bind to: %pI4, error: %d\n",
+					 &saddr4->sin_addr.s_addr, rc);
+		}
+	}
+	return rc;
+}
+
+static int
+ip_rfc1001_connect(struct TCP_Server_Info *server)
+{
+	int rc = 0;
+	/*
+	 * some servers require RFC1001 sessinit before sending
+	 * negprot - BB check reconnection in case where second
+	 * sessinit is sent but no second negprot
+	 */
+	struct rfc1002_session_packet req = {};
+	struct smb_hdr *smb_buf = (struct smb_hdr *)&req;
+	unsigned int len;
+
+	req.trailer.session_req.called_len = sizeof(req.trailer.session_req.called_name);
+
+	if (server->server_RFC1001_name[0] != 0)
+		rfc1002mangle(req.trailer.session_req.called_name,
+			      server->server_RFC1001_name,
+			      RFC1001_NAME_LEN_WITH_NULL);
+	else
+		rfc1002mangle(req.trailer.session_req.called_name,
+			      DEFAULT_CIFS_CALLED_NAME,
+			      RFC1001_NAME_LEN_WITH_NULL);
+
+	req.trailer.session_req.calling_len = sizeof(req.trailer.session_req.calling_name);
+
+	/* calling name ends in null (byte 16) from old smb convention */
+	if (server->workstation_RFC1001_name[0] != 0)
+		rfc1002mangle(req.trailer.session_req.calling_name,
+			      server->workstation_RFC1001_name,
+			      RFC1001_NAME_LEN_WITH_NULL);
+	else
+		rfc1002mangle(req.trailer.session_req.calling_name,
+			      "LINUX_CIFS_CLNT",
+			      RFC1001_NAME_LEN_WITH_NULL);
+
+	/*
+	 * As per rfc1002, @len must be the number of bytes that follows the
+	 * length field of a rfc1002 session request payload.
+	 */
+	len = sizeof(req) - offsetof(struct rfc1002_session_packet, trailer.session_req);
+
+	smb_buf->smb_buf_length = cpu_to_be32((RFC1002_SESSION_REQUEST << 24) | len);
+	rc = smb_send(server, smb_buf, len);
+	/*
+	 * RFC1001 layer in at least one server requires very short break before
+	 * negprot presumably because not expecting negprot to follow so fast.
+	 * This is a simple solution that works without complicating the code
+	 * and causes no significant slowing down on mount for everyone else
+	 */
+	usleep_range(1000, 2000);
+
+	return rc;
+}
+
+static int
+generic_ip_connect(struct TCP_Server_Info *server)
+{
+	int rc = 0;
+	__be16 sport;
+	int slen, sfamily;
+	struct socket *socket = server->ssocket;
+	struct sockaddr *saddr;
+
+	saddr = (struct sockaddr *) &server->dstaddr;
+
+	if (server->dstaddr.ss_family == AF_INET6) {
+		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)&server->dstaddr;
+
+		sport = ipv6->sin6_port;
+		slen = sizeof(struct sockaddr_in6);
+		sfamily = AF_INET6;
+		cifs_dbg(FYI, "%s: connecting to [%pI6]:%d\n", __func__, &ipv6->sin6_addr,
+				ntohs(sport));
+	} else {
+		struct sockaddr_in *ipv4 = (struct sockaddr_in *)&server->dstaddr;
+
+		sport = ipv4->sin_port;
+		slen = sizeof(struct sockaddr_in);
+		sfamily = AF_INET;
+		cifs_dbg(FYI, "%s: connecting to %pI4:%d\n", __func__, &ipv4->sin_addr,
+				ntohs(sport));
+	}
+
+	if (socket == NULL) {
+		rc = __sock_create(cifs_net_ns(server), sfamily, SOCK_STREAM,
+				   IPPROTO_TCP, &socket, 1);
+		if (rc < 0) {
+			cifs_server_dbg(VFS, "Error %d creating socket\n", rc);
+			server->ssocket = NULL;
+			return rc;
+		}
+
+		/* BB other socket options to set KEEPALIVE, NODELAY? */
+		cifs_dbg(FYI, "Socket created\n");
+		server->ssocket = socket;
+		socket->sk->sk_allocation = GFP_NOFS;
+		if (sfamily == AF_INET6)
+			cifs_reclassify_socket6(socket);
+		else
+			cifs_reclassify_socket4(socket);
+	}
+
+	rc = bind_socket(server);
+	if (rc < 0)
+		return rc;
+
+	/*
+	 * Eventually check for other socket options to change from
+	 * the default. sock_setsockopt not used because it expects
+	 * user space buffer
+	 */
+	socket->sk->sk_rcvtimeo = 7 * HZ;
+	socket->sk->sk_sndtimeo = 5 * HZ;
+
+	/* make the bufsizes depend on wsize/rsize and max requests */
+	if (server->noautotune) {
+		if (socket->sk->sk_sndbuf < (200 * 1024))
+			socket->sk->sk_sndbuf = 200 * 1024;
+		if (socket->sk->sk_rcvbuf < (140 * 1024))
+			socket->sk->sk_rcvbuf = 140 * 1024;
+	}
+
+	if (server->tcp_nodelay)
+		tcp_sock_set_nodelay(socket->sk);
+
+	cifs_dbg(FYI, "sndbuf %d rcvbuf %d rcvtimeo 0x%lx\n",
+		 socket->sk->sk_sndbuf,
+		 socket->sk->sk_rcvbuf, socket->sk->sk_rcvtimeo);
+
+	rc = kernel_connect(socket, saddr, slen,
+			    server->noblockcnt ? O_NONBLOCK : 0);
+	/*
+	 * When mounting SMB root file systems, we do not want to block in
+	 * connect. Otherwise bail out and then let cifs_reconnect() perform
+	 * reconnect failover - if possible.
+	 */
+	if (server->noblockcnt && rc == -EINPROGRESS)
+		rc = 0;
+	if (rc < 0) {
+		cifs_dbg(FYI, "Error %d connecting to server\n", rc);
+		trace_smb3_connect_err(server->hostname, server->conn_id, &server->dstaddr, rc);
+		sock_release(socket);
+		server->ssocket = NULL;
+		return rc;
+	}
+	trace_smb3_connect_done(server->hostname, server->conn_id, &server->dstaddr);
+	if (sport == htons(RFC1001_PORT))
+		rc = ip_rfc1001_connect(server);
+
+	return rc;
+}
+
+static int
+ip_connect(struct TCP_Server_Info *server)
+{
+	__be16 *sport;
+	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
+	struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
+
+	if (server->dstaddr.ss_family == AF_INET6)
+		sport = &addr6->sin6_port;
+	else
+		sport = &addr->sin_port;
+
+	if (*sport == 0) {
+		int rc;
+
+		/* try with 445 port at first */
+		*sport = htons(CIFS_PORT);
+
+		rc = generic_ip_connect(server);
+		if (rc >= 0)
+			return rc;
+
+		/* if it failed, try with 139 port */
+		*sport = htons(RFC1001_PORT);
+	}
+
+	return generic_ip_connect(server);
+}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+void reset_cifs_unix_caps(unsigned int xid, struct cifs_tcon *tcon,
+			  struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
+{
+	/*
+	 * If we are reconnecting then should we check to see if
+	 * any requested capabilities changed locally e.g. via
+	 * remount but we can not do much about it here
+	 * if they have (even if we could detect it by the following)
+	 * Perhaps we could add a backpointer to array of sb from tcon
+	 * or if we change to make all sb to same share the same
+	 * sb as NFS - then we only have one backpointer to sb.
+	 * What if we wanted to mount the server share twice once with
+	 * and once without posixacls or posix paths?
+	 */
+	__u64 saved_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
+
+	if (ctx && ctx->no_linux_ext) {
+		tcon->fsUnixInfo.Capability = 0;
+		tcon->unix_ext = 0; /* Unix Extensions disabled */
+		cifs_dbg(FYI, "Linux protocol extensions disabled\n");
+		return;
+	} else if (ctx)
+		tcon->unix_ext = 1; /* Unix Extensions supported */
+
+	if (!tcon->unix_ext) {
+		cifs_dbg(FYI, "Unix extensions disabled so not set on reconnect\n");
+		return;
+	}
+
+	if (!CIFSSMBQFSUnixInfo(xid, tcon)) {
+		__u64 cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
+		cifs_dbg(FYI, "unix caps which server supports %lld\n", cap);
+		/*
+		 * check for reconnect case in which we do not
+		 * want to change the mount behavior if we can avoid it
+		 */
+		if (ctx == NULL) {
+			/*
+			 * turn off POSIX ACL and PATHNAMES if not set
+			 * originally at mount time
+			 */
+			if ((saved_cap & CIFS_UNIX_POSIX_ACL_CAP) == 0)
+				cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
+			if ((saved_cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
+				if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
+					cifs_dbg(VFS, "POSIXPATH support change\n");
+				cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
+			} else if ((cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
+				cifs_dbg(VFS, "possible reconnect error\n");
+				cifs_dbg(VFS, "server disabled POSIX path support\n");
+			}
+		}
+
+		if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
+			cifs_dbg(VFS, "per-share encryption not supported yet\n");
+
+		cap &= CIFS_UNIX_CAP_MASK;
+		if (ctx && ctx->no_psx_acl)
+			cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
+		else if (CIFS_UNIX_POSIX_ACL_CAP & cap) {
+			cifs_dbg(FYI, "negotiated posix acl support\n");
+			if (cifs_sb)
+				cifs_sb->mnt_cifs_flags |=
+					CIFS_MOUNT_POSIXACL;
+		}
+
+		if (ctx && ctx->posix_paths == 0)
+			cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
+		else if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) {
+			cifs_dbg(FYI, "negotiate posix pathnames\n");
+			if (cifs_sb)
+				cifs_sb->mnt_cifs_flags |=
+					CIFS_MOUNT_POSIX_PATHS;
+		}
+
+		cifs_dbg(FYI, "Negotiate caps 0x%x\n", (int)cap);
+#ifdef CONFIG_CIFS_DEBUG2
+		if (cap & CIFS_UNIX_FCNTL_CAP)
+			cifs_dbg(FYI, "FCNTL cap\n");
+		if (cap & CIFS_UNIX_EXTATTR_CAP)
+			cifs_dbg(FYI, "EXTATTR cap\n");
+		if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
+			cifs_dbg(FYI, "POSIX path cap\n");
+		if (cap & CIFS_UNIX_XATTR_CAP)
+			cifs_dbg(FYI, "XATTR cap\n");
+		if (cap & CIFS_UNIX_POSIX_ACL_CAP)
+			cifs_dbg(FYI, "POSIX ACL cap\n");
+		if (cap & CIFS_UNIX_LARGE_READ_CAP)
+			cifs_dbg(FYI, "very large read cap\n");
+		if (cap & CIFS_UNIX_LARGE_WRITE_CAP)
+			cifs_dbg(FYI, "very large write cap\n");
+		if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_CAP)
+			cifs_dbg(FYI, "transport encryption cap\n");
+		if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
+			cifs_dbg(FYI, "mandatory transport encryption cap\n");
+#endif /* CIFS_DEBUG2 */
+		if (CIFSSMBSetFSUnixInfo(xid, tcon, cap)) {
+			if (ctx == NULL)
+				cifs_dbg(FYI, "resetting capabilities failed\n");
+			else
+				cifs_dbg(VFS, "Negotiating Unix capabilities with the server failed. Consider mounting with the Unix Extensions disabled if problems are found by specifying the nounix mount option.\n");
+
+		}
+	}
+}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb)
+{
+	struct smb3_fs_context *ctx = cifs_sb->ctx;
+
+	INIT_DELAYED_WORK(&cifs_sb->prune_tlinks, cifs_prune_tlinks);
+
+	spin_lock_init(&cifs_sb->tlink_tree_lock);
+	cifs_sb->tlink_tree = RB_ROOT;
+
+	cifs_dbg(FYI, "file mode: %04ho  dir mode: %04ho\n",
+		 ctx->file_mode, ctx->dir_mode);
+
+	/* this is needed for ASCII cp to Unicode converts */
+	if (ctx->iocharset == NULL) {
+		/* load_nls_default cannot return null */
+		cifs_sb->local_nls = load_nls_default();
+	} else {
+		cifs_sb->local_nls = load_nls(ctx->iocharset);
+		if (cifs_sb->local_nls == NULL) {
+			cifs_dbg(VFS, "CIFS mount error: iocharset %s not found\n",
+				 ctx->iocharset);
+			return -ELIBACC;
+		}
+	}
+	ctx->local_nls = cifs_sb->local_nls;
+
+	smb3_update_mnt_flags(cifs_sb);
+
+	if (ctx->direct_io)
+		cifs_dbg(FYI, "mounting share using direct i/o\n");
+	if (ctx->cache_ro) {
+		cifs_dbg(VFS, "mounting share with read only caching. Ensure that the share will not be modified while in use.\n");
+		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RO_CACHE;
+	} else if (ctx->cache_rw) {
+		cifs_dbg(VFS, "mounting share in single client RW caching mode. Ensure that no other systems will be accessing the share.\n");
+		cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_RO_CACHE |
+					    CIFS_MOUNT_RW_CACHE);
+	}
+
+	if ((ctx->cifs_acl) && (ctx->dynperm))
+		cifs_dbg(VFS, "mount option dynperm ignored if cifsacl mount option supported\n");
+
+	if (ctx->prepath) {
+		cifs_sb->prepath = kstrdup(ctx->prepath, GFP_KERNEL);
+		if (cifs_sb->prepath == NULL)
+			return -ENOMEM;
+		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
+	}
+
+	return 0;
+}
+
+/* Release all succeed connections */
+static inline void mount_put_conns(struct mount_ctx *mnt_ctx)
+{
+	int rc = 0;
+
+	if (mnt_ctx->tcon)
+		cifs_put_tcon(mnt_ctx->tcon);
+	else if (mnt_ctx->ses)
+		cifs_put_smb_ses(mnt_ctx->ses);
+	else if (mnt_ctx->server)
+		cifs_put_tcp_session(mnt_ctx->server, 0);
+	mnt_ctx->cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
+	free_xid(mnt_ctx->xid);
+}
+
+/* Get connections for tcp, ses and tcon */
+static int mount_get_conns(struct mount_ctx *mnt_ctx)
+{
+	int rc = 0;
+	struct TCP_Server_Info *server = NULL;
+	struct cifs_ses *ses = NULL;
+	struct cifs_tcon *tcon = NULL;
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	unsigned int xid;
+
+	xid = get_xid();
+
+	/* get a reference to a tcp session */
+	server = cifs_get_tcp_session(ctx, NULL);
+	if (IS_ERR(server)) {
+		rc = PTR_ERR(server);
+		server = NULL;
+		goto out;
+	}
+
+	/* get a reference to a SMB session */
+	ses = cifs_get_smb_ses(server, ctx);
+	if (IS_ERR(ses)) {
+		rc = PTR_ERR(ses);
+		ses = NULL;
+		goto out;
+	}
+
+	if ((ctx->persistent == true) && (!(ses->server->capabilities &
+					    SMB2_GLOBAL_CAP_PERSISTENT_HANDLES))) {
+		cifs_server_dbg(VFS, "persistent handles not supported by server\n");
+		rc = -EOPNOTSUPP;
+		goto out;
+	}
+
+	/* search for existing tcon to this server share */
+	tcon = cifs_get_tcon(ses, ctx);
+	if (IS_ERR(tcon)) {
+		rc = PTR_ERR(tcon);
+		tcon = NULL;
+		goto out;
+	}
+
+	/* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
+	if (tcon->posix_extensions)
+		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_POSIX_PATHS;
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	/* tell server which Unix caps we support */
+	if (cap_unix(tcon->ses)) {
+		/*
+		 * reset of caps checks mount to see if unix extensions disabled
+		 * for just this mount.
+		 */
+		reset_cifs_unix_caps(xid, tcon, cifs_sb, ctx);
+		spin_lock(&tcon->ses->server->srv_lock);
+		if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
+		    (le64_to_cpu(tcon->fsUnixInfo.Capability) &
+		     CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)) {
+			spin_unlock(&tcon->ses->server->srv_lock);
+			rc = -EACCES;
+			goto out;
+		}
+		spin_unlock(&tcon->ses->server->srv_lock);
+	} else
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+		tcon->unix_ext = 0; /* server does not support them */
+
+	/* do not care if a following call succeed - informational */
+	if (!tcon->pipe && server->ops->qfs_tcon) {
+		server->ops->qfs_tcon(xid, tcon, cifs_sb);
+		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RO_CACHE) {
+			if (tcon->fsDevInfo.DeviceCharacteristics &
+			    cpu_to_le32(FILE_READ_ONLY_DEVICE))
+				cifs_dbg(VFS, "mounted to read only share\n");
+			else if ((cifs_sb->mnt_cifs_flags &
+				  CIFS_MOUNT_RW_CACHE) == 0)
+				cifs_dbg(VFS, "read only mount of RW share\n");
+			/* no need to log a RW mount of a typical RW share */
+		}
+	}
+
+	/*
+	 * Clamp the rsize/wsize mount arguments if they are too big for the server
+	 * and set the rsize/wsize to the negotiated values if not passed in by
+	 * the user on mount
+	 */
+	if ((cifs_sb->ctx->wsize == 0) ||
+	    (cifs_sb->ctx->wsize > server->ops->negotiate_wsize(tcon, ctx)))
+		cifs_sb->ctx->wsize = server->ops->negotiate_wsize(tcon, ctx);
+	if ((cifs_sb->ctx->rsize == 0) ||
+	    (cifs_sb->ctx->rsize > server->ops->negotiate_rsize(tcon, ctx)))
+		cifs_sb->ctx->rsize = server->ops->negotiate_rsize(tcon, ctx);
+
+	/*
+	 * The cookie is initialized from volume info returned above.
+	 * Inside cifs_fscache_get_super_cookie it checks
+	 * that we do not get super cookie twice.
+	 */
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_FSCACHE)
+		cifs_fscache_get_super_cookie(tcon);
+
+out:
+	mnt_ctx->server = server;
+	mnt_ctx->ses = ses;
+	mnt_ctx->tcon = tcon;
+	mnt_ctx->xid = xid;
+
+	return rc;
+}
+
+static int mount_setup_tlink(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
+			     struct cifs_tcon *tcon)
+{
+	struct tcon_link *tlink;
+
+	/* hang the tcon off of the superblock */
+	tlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
+	if (tlink == NULL)
+		return -ENOMEM;
+
+	tlink->tl_uid = ses->linux_uid;
+	tlink->tl_tcon = tcon;
+	tlink->tl_time = jiffies;
+	set_bit(TCON_LINK_MASTER, &tlink->tl_flags);
+	set_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
+
+	cifs_sb->master_tlink = tlink;
+	spin_lock(&cifs_sb->tlink_tree_lock);
+	tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
+	spin_unlock(&cifs_sb->tlink_tree_lock);
+
+	queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
+				TLINK_IDLE_EXPIRE);
+	return 0;
+}
+
+#ifdef CONFIG_CIFS_DFS_UPCALL
+/* Get unique dfs connections */
+static int mount_get_dfs_conns(struct mount_ctx *mnt_ctx)
+{
+	int rc;
+
+	mnt_ctx->fs_ctx->nosharesock = true;
+	rc = mount_get_conns(mnt_ctx);
+	if (mnt_ctx->server) {
+		cifs_dbg(FYI, "%s: marking tcp session as a dfs connection\n", __func__);
+		spin_lock(&mnt_ctx->server->srv_lock);
+		mnt_ctx->server->is_dfs_conn = true;
+		spin_unlock(&mnt_ctx->server->srv_lock);
+	}
+	return rc;
+}
+
+/*
+ * cifs_build_path_to_root returns full path to root when we do not have an
+ * existing connection (tcon)
+ */
+static char *
+build_unc_path_to_root(const struct smb3_fs_context *ctx,
+		       const struct cifs_sb_info *cifs_sb, bool useppath)
+{
+	char *full_path, *pos;
+	unsigned int pplen = useppath && ctx->prepath ?
+		strlen(ctx->prepath) + 1 : 0;
+	unsigned int unc_len = strnlen(ctx->UNC, MAX_TREE_SIZE + 1);
+
+	if (unc_len > MAX_TREE_SIZE)
+		return ERR_PTR(-EINVAL);
+
+	full_path = kmalloc(unc_len + pplen + 1, GFP_KERNEL);
+	if (full_path == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	memcpy(full_path, ctx->UNC, unc_len);
+	pos = full_path + unc_len;
+
+	if (pplen) {
+		*pos = CIFS_DIR_SEP(cifs_sb);
+		memcpy(pos + 1, ctx->prepath, pplen);
+		pos += pplen;
+	}
+
+	*pos = '\0'; /* add trailing null */
+	convert_delimiter(full_path, CIFS_DIR_SEP(cifs_sb));
+	cifs_dbg(FYI, "%s: full_path=%s\n", __func__, full_path);
+	return full_path;
+}
+
+/*
+ * expand_dfs_referral - Update cifs_sb from dfs referral path
+ *
+ * cifs_sb->ctx->mount_options will be (re-)allocated to a string containing updated options for the
+ * submount.  Otherwise it will be left untouched.
+ */
+static int expand_dfs_referral(struct mount_ctx *mnt_ctx, const char *full_path,
+			       struct dfs_info3_param *referral)
+{
+	int rc;
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	char *fake_devname = NULL, *mdata = NULL;
+
+	mdata = cifs_compose_mount_options(cifs_sb->ctx->mount_options, full_path + 1, referral,
+					   &fake_devname);
+	if (IS_ERR(mdata)) {
+		rc = PTR_ERR(mdata);
+		mdata = NULL;
+	} else {
+		/*
+		 * We can not clear out the whole structure since we no longer have an explicit
+		 * function to parse a mount-string. Instead we need to clear out the individual
+		 * fields that are no longer valid.
+		 */
+		kfree(ctx->prepath);
+		ctx->prepath = NULL;
+		rc = cifs_setup_volume_info(ctx, mdata, fake_devname);
+	}
+	kfree(fake_devname);
+	kfree(cifs_sb->ctx->mount_options);
+	cifs_sb->ctx->mount_options = mdata;
+
+	return rc;
+}
+#endif
+
+/* TODO: all callers to this are broken. We are not parsing mount_options here
+ * we should pass a clone of the original context?
+ */
+int
+cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname)
+{
+	int rc;
+
+	if (devname) {
+		cifs_dbg(FYI, "%s: devname=%s\n", __func__, devname);
+		rc = smb3_parse_devname(devname, ctx);
+		if (rc) {
+			cifs_dbg(VFS, "%s: failed to parse %s: %d\n", __func__, devname, rc);
+			return rc;
+		}
+	}
+
+	if (mntopts) {
+		char *ip;
+
+		rc = smb3_parse_opt(mntopts, "ip", &ip);
+		if (rc) {
+			cifs_dbg(VFS, "%s: failed to parse ip options: %d\n", __func__, rc);
+			return rc;
+		}
+
+		rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip));
+		kfree(ip);
+		if (!rc) {
+			cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);
+			return -EINVAL;
+		}
+	}
+
+	if (ctx->nullauth) {
+		cifs_dbg(FYI, "Anonymous login\n");
+		kfree(ctx->username);
+		ctx->username = NULL;
+	} else if (ctx->username) {
+		/* BB fixme parse for domain name here */
+		cifs_dbg(FYI, "Username: %s\n", ctx->username);
+	} else {
+		cifs_dbg(VFS, "No username specified\n");
+	/* In userspace mount helper we can get user name from alternate
+	   locations such as env variables and files on disk */
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int
+cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
+					unsigned int xid,
+					struct cifs_tcon *tcon,
+					struct cifs_sb_info *cifs_sb,
+					char *full_path,
+					int added_treename)
+{
+	int rc;
+	char *s;
+	char sep, tmp;
+	int skip = added_treename ? 1 : 0;
+
+	sep = CIFS_DIR_SEP(cifs_sb);
+	s = full_path;
+
+	rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, "");
+	while (rc == 0) {
+		/* skip separators */
+		while (*s == sep)
+			s++;
+		if (!*s)
+			break;
+		/* next separator */
+		while (*s && *s != sep)
+			s++;
+		/*
+		 * if the treename is added, we then have to skip the first
+		 * part within the separators
+		 */
+		if (skip) {
+			skip = 0;
+			continue;
+		}
+		/*
+		 * temporarily null-terminate the path at the end of
+		 * the current component
+		 */
+		tmp = *s;
+		*s = 0;
+		rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
+						     full_path);
+		*s = tmp;
+	}
+	return rc;
+}
+
+/*
+ * Check if path is remote (i.e. a DFS share).
+ *
+ * Return -EREMOTE if it is, otherwise 0 or -errno.
+ */
+static int is_path_remote(struct mount_ctx *mnt_ctx)
+{
+	int rc;
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct TCP_Server_Info *server = mnt_ctx->server;
+	unsigned int xid = mnt_ctx->xid;
+	struct cifs_tcon *tcon = mnt_ctx->tcon;
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	char *full_path;
+
+	if (!server->ops->is_path_accessible)
+		return -EOPNOTSUPP;
+
+	/*
+	 * cifs_build_path_to_root works only when we have a valid tcon
+	 */
+	full_path = cifs_build_path_to_root(ctx, cifs_sb, tcon,
+					    tcon->Flags & SMB_SHARE_IS_IN_DFS);
+	if (full_path == NULL)
+		return -ENOMEM;
+
+	cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
+
+	rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
+					     full_path);
+	if (rc != 0 && rc != -EREMOTE)
+		goto out;
+
+	if (rc != -EREMOTE) {
+		rc = cifs_are_all_path_components_accessible(server, xid, tcon,
+			cifs_sb, full_path, tcon->Flags & SMB_SHARE_IS_IN_DFS);
+		if (rc != 0) {
+			cifs_server_dbg(VFS, "cannot query dirs between root and final path, enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
+			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
+			rc = 0;
+		}
+	}
+
+out:
+	kfree(full_path);
+	return rc;
+}
+
+#ifdef CONFIG_CIFS_DFS_UPCALL
+static void set_root_ses(struct mount_ctx *mnt_ctx)
+{
+	if (mnt_ctx->ses) {
+		spin_lock(&cifs_tcp_ses_lock);
+		mnt_ctx->ses->ses_count++;
+		spin_unlock(&cifs_tcp_ses_lock);
+		dfs_cache_add_refsrv_session(&mnt_ctx->mount_id, mnt_ctx->ses);
+	}
+	mnt_ctx->root_ses = mnt_ctx->ses;
+}
+
+static int is_dfs_mount(struct mount_ctx *mnt_ctx, bool *isdfs, struct dfs_cache_tgt_list *root_tl)
+{
+	int rc;
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+
+	*isdfs = true;
+
+	rc = mount_get_conns(mnt_ctx);
+	/*
+	 * If called with 'nodfs' mount option, then skip DFS resolving.  Otherwise unconditionally
+	 * try to get an DFS referral (even cached) to determine whether it is an DFS mount.
+	 *
+	 * Skip prefix path to provide support for DFS referrals from w2k8 servers which don't seem
+	 * to respond with PATH_NOT_COVERED to requests that include the prefix.
+	 */
+	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
+	    dfs_cache_find(mnt_ctx->xid, mnt_ctx->ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
+			   ctx->UNC + 1, NULL, root_tl)) {
+		if (rc)
+			return rc;
+		/* Check if it is fully accessible and then mount it */
+		rc = is_path_remote(mnt_ctx);
+		if (!rc)
+			*isdfs = false;
+		else if (rc != -EREMOTE)
+			return rc;
+	}
+	return 0;
+}
+
+static int connect_dfs_target(struct mount_ctx *mnt_ctx, const char *full_path,
+			      const char *ref_path, struct dfs_cache_tgt_iterator *tit)
+{
+	int rc;
+	struct dfs_info3_param ref = {};
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	char *oldmnt = cifs_sb->ctx->mount_options;
+
+	cifs_dbg(FYI, "%s: full_path=%s ref_path=%s target=%s\n", __func__, full_path, ref_path,
+		 dfs_cache_get_tgt_name(tit));
+
+	rc = dfs_cache_get_tgt_referral(ref_path, tit, &ref);
+	if (rc)
+		goto out;
+
+	rc = expand_dfs_referral(mnt_ctx, full_path, &ref);
+	if (rc)
+		goto out;
+
+	/* Connect to new target only if we were redirected (e.g. mount options changed) */
+	if (oldmnt != cifs_sb->ctx->mount_options) {
+		mount_put_conns(mnt_ctx);
+		rc = mount_get_dfs_conns(mnt_ctx);
+	}
+	if (!rc) {
+		if (cifs_is_referral_server(mnt_ctx->tcon, &ref))
+			set_root_ses(mnt_ctx);
+		rc = dfs_cache_update_tgthint(mnt_ctx->xid, mnt_ctx->root_ses, cifs_sb->local_nls,
+					      cifs_remap(cifs_sb), ref_path, tit);
+	}
+
+out:
+	free_dfs_info_param(&ref);
+	return rc;
+}
+
+static int connect_dfs_root(struct mount_ctx *mnt_ctx, struct dfs_cache_tgt_list *root_tl)
+{
+	int rc;
+	char *full_path;
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	struct dfs_cache_tgt_iterator *tit;
+
+	/* Put initial connections as they might be shared with other mounts.  We need unique dfs
+	 * connections per mount to properly failover, so mount_get_dfs_conns() must be used from
+	 * now on.
+	 */
+	mount_put_conns(mnt_ctx);
+	mount_get_dfs_conns(mnt_ctx);
+	set_root_ses(mnt_ctx);
+
+	full_path = build_unc_path_to_root(ctx, cifs_sb, true);
+	if (IS_ERR(full_path))
+		return PTR_ERR(full_path);
+
+	mnt_ctx->origin_fullpath = dfs_cache_canonical_path(ctx->UNC, cifs_sb->local_nls,
+							    cifs_remap(cifs_sb));
+	if (IS_ERR(mnt_ctx->origin_fullpath)) {
+		rc = PTR_ERR(mnt_ctx->origin_fullpath);
+		mnt_ctx->origin_fullpath = NULL;
+		goto out;
+	}
+
+	/* Try all dfs root targets */
+	for (rc = -ENOENT, tit = dfs_cache_get_tgt_iterator(root_tl);
+	     tit; tit = dfs_cache_get_next_tgt(root_tl, tit)) {
+		rc = connect_dfs_target(mnt_ctx, full_path, mnt_ctx->origin_fullpath + 1, tit);
+		if (!rc) {
+			mnt_ctx->leaf_fullpath = kstrdup(mnt_ctx->origin_fullpath, GFP_KERNEL);
+			if (!mnt_ctx->leaf_fullpath)
+				rc = -ENOMEM;
+			break;
+		}
+	}
+
+out:
+	kfree(full_path);
+	return rc;
+}
+
+static int __follow_dfs_link(struct mount_ctx *mnt_ctx)
+{
+	int rc;
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	char *full_path;
+	struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
+	struct dfs_cache_tgt_iterator *tit;
+
+	full_path = build_unc_path_to_root(ctx, cifs_sb, true);
+	if (IS_ERR(full_path))
+		return PTR_ERR(full_path);
+
+	kfree(mnt_ctx->leaf_fullpath);
+	mnt_ctx->leaf_fullpath = dfs_cache_canonical_path(full_path, cifs_sb->local_nls,
+							  cifs_remap(cifs_sb));
+	if (IS_ERR(mnt_ctx->leaf_fullpath)) {
+		rc = PTR_ERR(mnt_ctx->leaf_fullpath);
+		mnt_ctx->leaf_fullpath = NULL;
+		goto out;
+	}
+
+	/* Get referral from dfs link */
+	rc = dfs_cache_find(mnt_ctx->xid, mnt_ctx->root_ses, cifs_sb->local_nls,
+			    cifs_remap(cifs_sb), mnt_ctx->leaf_fullpath + 1, NULL, &tl);
+	if (rc)
+		goto out;
+
+	/* Try all dfs link targets.  If an I/O fails from currently connected DFS target with an
+	 * error other than STATUS_PATH_NOT_COVERED (-EREMOTE), then retry it from other targets as
+	 * specified in MS-DFSC "3.1.5.2 I/O Operation to Target Fails with an Error Other Than
+	 * STATUS_PATH_NOT_COVERED."
+	 */
+	for (rc = -ENOENT, tit = dfs_cache_get_tgt_iterator(&tl);
+	     tit; tit = dfs_cache_get_next_tgt(&tl, tit)) {
+		rc = connect_dfs_target(mnt_ctx, full_path, mnt_ctx->leaf_fullpath + 1, tit);
+		if (!rc) {
+			rc = is_path_remote(mnt_ctx);
+			if (!rc || rc == -EREMOTE)
+				break;
+		}
+	}
+
+out:
+	kfree(full_path);
+	dfs_cache_free_tgts(&tl);
+	return rc;
+}
+
+static int follow_dfs_link(struct mount_ctx *mnt_ctx)
+{
+	int rc;
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	char *full_path;
+	int num_links = 0;
+
+	full_path = build_unc_path_to_root(ctx, cifs_sb, true);
+	if (IS_ERR(full_path))
+		return PTR_ERR(full_path);
+
+	kfree(mnt_ctx->origin_fullpath);
+	mnt_ctx->origin_fullpath = dfs_cache_canonical_path(full_path, cifs_sb->local_nls,
+							    cifs_remap(cifs_sb));
+	kfree(full_path);
+
+	if (IS_ERR(mnt_ctx->origin_fullpath)) {
+		rc = PTR_ERR(mnt_ctx->origin_fullpath);
+		mnt_ctx->origin_fullpath = NULL;
+		return rc;
+	}
+
+	do {
+		rc = __follow_dfs_link(mnt_ctx);
+		if (!rc || rc != -EREMOTE)
+			break;
+	} while (rc = -ELOOP, ++num_links < MAX_NESTED_LINKS);
+
+	return rc;
+}
+
+/* Set up DFS referral paths for failover */
+static void setup_server_referral_paths(struct mount_ctx *mnt_ctx)
+{
+	struct TCP_Server_Info *server = mnt_ctx->server;
+
+	mutex_lock(&server->refpath_lock);
+	server->origin_fullpath = mnt_ctx->origin_fullpath;
+	server->leaf_fullpath = mnt_ctx->leaf_fullpath;
+	server->current_fullpath = mnt_ctx->leaf_fullpath;
+	mutex_unlock(&server->refpath_lock);
+	mnt_ctx->origin_fullpath = mnt_ctx->leaf_fullpath = NULL;
+}
+
+int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
+{
+	int rc;
+	struct mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
+	struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
+	bool isdfs;
+
+	rc = is_dfs_mount(&mnt_ctx, &isdfs, &tl);
+	if (rc)
+		goto error;
+	if (!isdfs)
+		goto out;
+
+	/* proceed as DFS mount */
+	uuid_gen(&mnt_ctx.mount_id);
+	rc = connect_dfs_root(&mnt_ctx, &tl);
+	dfs_cache_free_tgts(&tl);
+
+	if (rc)
+		goto error;
+
+	rc = is_path_remote(&mnt_ctx);
+	if (rc)
+		rc = follow_dfs_link(&mnt_ctx);
+	if (rc)
+		goto error;
+
+	setup_server_referral_paths(&mnt_ctx);
+	/*
+	 * After reconnecting to a different server, unique ids won't match anymore, so we disable
+	 * serverino. This prevents dentry revalidation to think the dentry are stale (ESTALE).
+	 */
+	cifs_autodisable_serverino(cifs_sb);
+	/*
+	 * Force the use of prefix path to support failover on DFS paths that resolve to targets
+	 * that have different prefix paths.
+	 */
+	cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
+	kfree(cifs_sb->prepath);
+	cifs_sb->prepath = ctx->prepath;
+	ctx->prepath = NULL;
+	uuid_copy(&cifs_sb->dfs_mount_id, &mnt_ctx.mount_id);
+
+out:
+	cifs_try_adding_channels(cifs_sb, mnt_ctx.ses);
+	rc = mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
+	if (rc)
+		goto error;
+
+	free_xid(mnt_ctx.xid);
+	return rc;
+
+error:
+	dfs_cache_put_refsrv_sessions(&mnt_ctx.mount_id);
+	kfree(mnt_ctx.origin_fullpath);
+	kfree(mnt_ctx.leaf_fullpath);
+	mount_put_conns(&mnt_ctx);
+	return rc;
+}
+#else
+int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
+{
+	int rc = 0;
+	struct mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
+
+	rc = mount_get_conns(&mnt_ctx);
+	if (rc)
+		goto error;
+
+	if (mnt_ctx.tcon) {
+		rc = is_path_remote(&mnt_ctx);
+		if (rc == -EREMOTE)
+			rc = -EOPNOTSUPP;
+		if (rc)
+			goto error;
+	}
+
+	rc = mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
+	if (rc)
+		goto error;
+
+	free_xid(mnt_ctx.xid);
+	return rc;
+
+error:
+	mount_put_conns(&mnt_ctx);
+	return rc;
+}
+#endif
+
+/*
+ * Issue a TREE_CONNECT request.
+ */
+int
+CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
+	 const char *tree, struct cifs_tcon *tcon,
+	 const struct nls_table *nls_codepage)
+{
+	struct smb_hdr *smb_buffer;
+	struct smb_hdr *smb_buffer_response;
+	TCONX_REQ *pSMB;
+	TCONX_RSP *pSMBr;
+	unsigned char *bcc_ptr;
+	int rc = 0;
+	int length;
+	__u16 bytes_left, count;
+
+	if (ses == NULL)
+		return -EIO;
+
+	smb_buffer = cifs_buf_get();
+	if (smb_buffer == NULL)
+		return -ENOMEM;
+
+	smb_buffer_response = smb_buffer;
+
+	header_assemble(smb_buffer, SMB_COM_TREE_CONNECT_ANDX,
+			NULL /*no tid */ , 4 /*wct */ );
+
+	smb_buffer->Mid = get_next_mid(ses->server);
+	smb_buffer->Uid = ses->Suid;
+	pSMB = (TCONX_REQ *) smb_buffer;
+	pSMBr = (TCONX_RSP *) smb_buffer_response;
+
+	pSMB->AndXCommand = 0xFF;
+	pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
+	bcc_ptr = &pSMB->Password[0];
+
+	pSMB->PasswordLength = cpu_to_le16(1);	/* minimum */
+	*bcc_ptr = 0; /* password is null byte */
+	bcc_ptr++;              /* skip password */
+	/* already aligned so no need to do it below */
+
+	if (ses->server->sign)
+		smb_buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
+
+	if (ses->capabilities & CAP_STATUS32) {
+		smb_buffer->Flags2 |= SMBFLG2_ERR_STATUS;
+	}
+	if (ses->capabilities & CAP_DFS) {
+		smb_buffer->Flags2 |= SMBFLG2_DFS;
+	}
+	if (ses->capabilities & CAP_UNICODE) {
+		smb_buffer->Flags2 |= SMBFLG2_UNICODE;
+		length =
+		    cifs_strtoUTF16((__le16 *) bcc_ptr, tree,
+			6 /* max utf8 char length in bytes */ *
+			(/* server len*/ + 256 /* share len */), nls_codepage);
+		bcc_ptr += 2 * length;	/* convert num 16 bit words to bytes */
+		bcc_ptr += 2;	/* skip trailing null */
+	} else {		/* ASCII */
+		strcpy(bcc_ptr, tree);
+		bcc_ptr += strlen(tree) + 1;
+	}
+	strcpy(bcc_ptr, "?????");
+	bcc_ptr += strlen("?????");
+	bcc_ptr += 1;
+	count = bcc_ptr - &pSMB->Password[0];
+	be32_add_cpu(&pSMB->hdr.smb_buf_length, count);
+	pSMB->ByteCount = cpu_to_le16(count);
+
+	rc = SendReceive(xid, ses, smb_buffer, smb_buffer_response, &length,
+			 0);
+
+	/* above now done in SendReceive */
+	if (rc == 0) {
+		bool is_unicode;
+
+		tcon->tid = smb_buffer_response->Tid;
+		bcc_ptr = pByteArea(smb_buffer_response);
+		bytes_left = get_bcc(smb_buffer_response);
+		length = strnlen(bcc_ptr, bytes_left - 2);
+		if (smb_buffer->Flags2 & SMBFLG2_UNICODE)
+			is_unicode = true;
+		else
+			is_unicode = false;
+
+
+		/* skip service field (NB: this field is always ASCII) */
+		if (length == 3) {
+			if ((bcc_ptr[0] == 'I') && (bcc_ptr[1] == 'P') &&
+			    (bcc_ptr[2] == 'C')) {
+				cifs_dbg(FYI, "IPC connection\n");
+				tcon->ipc = true;
+				tcon->pipe = true;
+			}
+		} else if (length == 2) {
+			if ((bcc_ptr[0] == 'A') && (bcc_ptr[1] == ':')) {
+				/* the most common case */
+				cifs_dbg(FYI, "disk share connection\n");
+			}
+		}
+		bcc_ptr += length + 1;
+		bytes_left -= (length + 1);
+		strscpy(tcon->tree_name, tree, sizeof(tcon->tree_name));
+
+		/* mostly informational -- no need to fail on error here */
+		kfree(tcon->nativeFileSystem);
+		tcon->nativeFileSystem = cifs_strndup_from_utf16(bcc_ptr,
+						      bytes_left, is_unicode,
+						      nls_codepage);
+
+		cifs_dbg(FYI, "nativeFileSystem=%s\n", tcon->nativeFileSystem);
+
+		if ((smb_buffer_response->WordCount == 3) ||
+			 (smb_buffer_response->WordCount == 7))
+			/* field is in same location */
+			tcon->Flags = le16_to_cpu(pSMBr->OptionalSupport);
+		else
+			tcon->Flags = 0;
+		cifs_dbg(FYI, "Tcon flags: 0x%x\n", tcon->Flags);
+	}
+
+	cifs_buf_release(smb_buffer);
+	return rc;
+}
+
+static void delayed_free(struct rcu_head *p)
+{
+	struct cifs_sb_info *cifs_sb = container_of(p, struct cifs_sb_info, rcu);
+
+	unload_nls(cifs_sb->local_nls);
+	smb3_cleanup_fs_context(cifs_sb->ctx);
+	kfree(cifs_sb);
+}
+
+void
+cifs_umount(struct cifs_sb_info *cifs_sb)
+{
+	struct rb_root *root = &cifs_sb->tlink_tree;
+	struct rb_node *node;
+	struct tcon_link *tlink;
+
+	cancel_delayed_work_sync(&cifs_sb->prune_tlinks);
+
+	spin_lock(&cifs_sb->tlink_tree_lock);
+	while ((node = rb_first(root))) {
+		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
+		cifs_get_tlink(tlink);
+		clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
+		rb_erase(node, root);
+
+		spin_unlock(&cifs_sb->tlink_tree_lock);
+		cifs_put_tlink(tlink);
+		spin_lock(&cifs_sb->tlink_tree_lock);
+	}
+	spin_unlock(&cifs_sb->tlink_tree_lock);
+
+	kfree(cifs_sb->prepath);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	dfs_cache_put_refsrv_sessions(&cifs_sb->dfs_mount_id);
+#endif
+	call_rcu(&cifs_sb->rcu, delayed_free);
+}
+
+int
+cifs_negotiate_protocol(const unsigned int xid, struct cifs_ses *ses,
+			struct TCP_Server_Info *server)
+{
+	int rc = 0;
+
+	if (!server->ops->need_neg || !server->ops->negotiate)
+		return -ENOSYS;
+
+	/* only send once per connect */
+	spin_lock(&server->srv_lock);
+	if (server->tcpStatus != CifsGood &&
+	    server->tcpStatus != CifsNew &&
+	    server->tcpStatus != CifsNeedNegotiate) {
+		spin_unlock(&server->srv_lock);
+		return -EHOSTDOWN;
+	}
+
+	if (!server->ops->need_neg(server) &&
+	    server->tcpStatus == CifsGood) {
+		spin_unlock(&server->srv_lock);
+		return 0;
+	}
+
+	server->tcpStatus = CifsInNegotiate;
+	spin_unlock(&server->srv_lock);
+
+	rc = server->ops->negotiate(xid, ses, server);
+	if (rc == 0) {
+		spin_lock(&server->srv_lock);
+		if (server->tcpStatus == CifsInNegotiate)
+			server->tcpStatus = CifsGood;
+		else
+			rc = -EHOSTDOWN;
+		spin_unlock(&server->srv_lock);
+	} else {
+		spin_lock(&server->srv_lock);
+		if (server->tcpStatus == CifsInNegotiate)
+			server->tcpStatus = CifsNeedNegotiate;
+		spin_unlock(&server->srv_lock);
+	}
+
+	return rc;
+}
+
+int
+cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
+		   struct TCP_Server_Info *server,
+		   struct nls_table *nls_info)
+{
+	int rc = -ENOSYS;
+	struct TCP_Server_Info *pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&pserver->dstaddr;
+	struct sockaddr_in *addr = (struct sockaddr_in *)&pserver->dstaddr;
+	bool is_binding = false;
+
+	spin_lock(&ses->ses_lock);
+	cifs_dbg(FYI, "%s: channel connect bitmap: 0x%lx\n",
+		 __func__, ses->chans_need_reconnect);
+
+	if (ses->ses_status != SES_GOOD &&
+	    ses->ses_status != SES_NEW &&
+	    ses->ses_status != SES_NEED_RECON) {
+		spin_unlock(&ses->ses_lock);
+		return -EHOSTDOWN;
+	}
+
+	/* only send once per connect */
+	spin_lock(&ses->chan_lock);
+	if (CIFS_ALL_CHANS_GOOD(ses)) {
+		if (ses->ses_status == SES_NEED_RECON)
+			ses->ses_status = SES_GOOD;
+		spin_unlock(&ses->chan_lock);
+		spin_unlock(&ses->ses_lock);
+		return 0;
+	}
+
+	cifs_chan_set_in_reconnect(ses, server);
+	is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
+	spin_unlock(&ses->chan_lock);
+
+	if (!is_binding) {
+		ses->ses_status = SES_IN_SETUP;
+
+		/* force iface_list refresh */
+		ses->iface_last_update = 0;
+	}
+	spin_unlock(&ses->ses_lock);
+
+	/* update ses ip_addr only for primary chan */
+	if (server == pserver) {
+		if (server->dstaddr.ss_family == AF_INET6)
+			scnprintf(ses->ip_addr, sizeof(ses->ip_addr), "%pI6", &addr6->sin6_addr);
+		else
+			scnprintf(ses->ip_addr, sizeof(ses->ip_addr), "%pI4", &addr->sin_addr);
+	}
+
+	if (!is_binding) {
+		ses->capabilities = server->capabilities;
+		if (!linuxExtEnabled)
+			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_sensitive(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 (server->ops->sess_setup)
+		rc = server->ops->sess_setup(xid, ses, server, nls_info);
+
+	if (rc) {
+		cifs_server_dbg(VFS, "Send error in SessSetup = %d\n", rc);
+		spin_lock(&ses->ses_lock);
+		if (ses->ses_status == SES_IN_SETUP)
+			ses->ses_status = SES_NEED_RECON;
+		spin_lock(&ses->chan_lock);
+		cifs_chan_clear_in_reconnect(ses, server);
+		spin_unlock(&ses->chan_lock);
+		spin_unlock(&ses->ses_lock);
+	} else {
+		spin_lock(&ses->ses_lock);
+		if (ses->ses_status == SES_IN_SETUP)
+			ses->ses_status = SES_GOOD;
+		spin_lock(&ses->chan_lock);
+		cifs_chan_clear_in_reconnect(ses, server);
+		cifs_chan_clear_need_reconnect(ses, server);
+		spin_unlock(&ses->chan_lock);
+		spin_unlock(&ses->ses_lock);
+	}
+
+	return rc;
+}
+
+static int
+cifs_set_vol_auth(struct smb3_fs_context *ctx, struct cifs_ses *ses)
+{
+	ctx->sectype = ses->sectype;
+
+	/* krb5 is special, since we don't need username or pw */
+	if (ctx->sectype == Kerberos)
+		return 0;
+
+	return cifs_set_cifscreds(ctx, ses);
+}
+
+static struct cifs_tcon *
+cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
+{
+	int rc;
+	struct cifs_tcon *master_tcon = cifs_sb_master_tcon(cifs_sb);
+	struct cifs_ses *ses;
+	struct cifs_tcon *tcon = NULL;
+	struct smb3_fs_context *ctx;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (ctx == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	ctx->local_nls = cifs_sb->local_nls;
+	ctx->linux_uid = fsuid;
+	ctx->cred_uid = fsuid;
+	ctx->UNC = master_tcon->tree_name;
+	ctx->retry = master_tcon->retry;
+	ctx->nocase = master_tcon->nocase;
+	ctx->nohandlecache = master_tcon->nohandlecache;
+	ctx->local_lease = master_tcon->local_lease;
+	ctx->no_lease = master_tcon->no_lease;
+	ctx->resilient = master_tcon->use_resilient;
+	ctx->persistent = master_tcon->use_persistent;
+	ctx->handle_timeout = master_tcon->handle_timeout;
+	ctx->no_linux_ext = !master_tcon->unix_ext;
+	ctx->linux_ext = master_tcon->posix_extensions;
+	ctx->sectype = master_tcon->ses->sectype;
+	ctx->sign = master_tcon->ses->sign;
+	ctx->seal = master_tcon->seal;
+	ctx->witness = master_tcon->use_witness;
+
+	rc = cifs_set_vol_auth(ctx, master_tcon->ses);
+	if (rc) {
+		tcon = ERR_PTR(rc);
+		goto out;
+	}
+
+	/* get a reference for the same TCP session */
+	spin_lock(&cifs_tcp_ses_lock);
+	++master_tcon->ses->server->srv_count;
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	ses = cifs_get_smb_ses(master_tcon->ses->server, ctx);
+	if (IS_ERR(ses)) {
+		tcon = (struct cifs_tcon *)ses;
+		cifs_put_tcp_session(master_tcon->ses->server, 0);
+		goto out;
+	}
+
+	tcon = cifs_get_tcon(ses, ctx);
+	if (IS_ERR(tcon)) {
+		cifs_put_smb_ses(ses);
+		goto out;
+	}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	if (cap_unix(ses))
+		reset_cifs_unix_caps(0, tcon, NULL, ctx);
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+out:
+	kfree(ctx->username);
+	kfree_sensitive(ctx->password);
+	kfree(ctx);
+
+	return tcon;
+}
+
+struct cifs_tcon *
+cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
+{
+	return tlink_tcon(cifs_sb_master_tlink(cifs_sb));
+}
+
+/* find and return a tlink with given uid */
+static struct tcon_link *
+tlink_rb_search(struct rb_root *root, kuid_t uid)
+{
+	struct rb_node *node = root->rb_node;
+	struct tcon_link *tlink;
+
+	while (node) {
+		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
+
+		if (uid_gt(tlink->tl_uid, uid))
+			node = node->rb_left;
+		else if (uid_lt(tlink->tl_uid, uid))
+			node = node->rb_right;
+		else
+			return tlink;
+	}
+	return NULL;
+}
+
+/* insert a tcon_link into the tree */
+static void
+tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink)
+{
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+	struct tcon_link *tlink;
+
+	while (*new) {
+		tlink = rb_entry(*new, struct tcon_link, tl_rbnode);
+		parent = *new;
+
+		if (uid_gt(tlink->tl_uid, new_tlink->tl_uid))
+			new = &((*new)->rb_left);
+		else
+			new = &((*new)->rb_right);
+	}
+
+	rb_link_node(&new_tlink->tl_rbnode, parent, new);
+	rb_insert_color(&new_tlink->tl_rbnode, root);
+}
+
+/*
+ * Find or construct an appropriate tcon given a cifs_sb and the fsuid of the
+ * current task.
+ *
+ * If the superblock doesn't refer to a multiuser mount, then just return
+ * the master tcon for the mount.
+ *
+ * First, search the rbtree for an existing tcon for this fsuid. If one
+ * exists, then check to see if it's pending construction. If it is then wait
+ * for construction to complete. Once it's no longer pending, check to see if
+ * it failed and either return an error or retry construction, depending on
+ * the timeout.
+ *
+ * If one doesn't exist then insert a new tcon_link struct into the tree and
+ * try to construct a new one.
+ */
+struct tcon_link *
+cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
+{
+	int ret;
+	kuid_t fsuid = current_fsuid();
+	struct tcon_link *tlink, *newtlink;
+
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
+		return cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
+
+	spin_lock(&cifs_sb->tlink_tree_lock);
+	tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
+	if (tlink)
+		cifs_get_tlink(tlink);
+	spin_unlock(&cifs_sb->tlink_tree_lock);
+
+	if (tlink == NULL) {
+		newtlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
+		if (newtlink == NULL)
+			return ERR_PTR(-ENOMEM);
+		newtlink->tl_uid = fsuid;
+		newtlink->tl_tcon = ERR_PTR(-EACCES);
+		set_bit(TCON_LINK_PENDING, &newtlink->tl_flags);
+		set_bit(TCON_LINK_IN_TREE, &newtlink->tl_flags);
+		cifs_get_tlink(newtlink);
+
+		spin_lock(&cifs_sb->tlink_tree_lock);
+		/* was one inserted after previous search? */
+		tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
+		if (tlink) {
+			cifs_get_tlink(tlink);
+			spin_unlock(&cifs_sb->tlink_tree_lock);
+			kfree(newtlink);
+			goto wait_for_construction;
+		}
+		tlink = newtlink;
+		tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
+		spin_unlock(&cifs_sb->tlink_tree_lock);
+	} else {
+wait_for_construction:
+		ret = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
+				  TASK_INTERRUPTIBLE);
+		if (ret) {
+			cifs_put_tlink(tlink);
+			return ERR_PTR(-ERESTARTSYS);
+		}
+
+		/* if it's good, return it */
+		if (!IS_ERR(tlink->tl_tcon))
+			return tlink;
+
+		/* return error if we tried this already recently */
+		if (time_before(jiffies, tlink->tl_time + TLINK_ERROR_EXPIRE)) {
+			cifs_put_tlink(tlink);
+			return ERR_PTR(-EACCES);
+		}
+
+		if (test_and_set_bit(TCON_LINK_PENDING, &tlink->tl_flags))
+			goto wait_for_construction;
+	}
+
+	tlink->tl_tcon = cifs_construct_tcon(cifs_sb, fsuid);
+	clear_bit(TCON_LINK_PENDING, &tlink->tl_flags);
+	wake_up_bit(&tlink->tl_flags, TCON_LINK_PENDING);
+
+	if (IS_ERR(tlink->tl_tcon)) {
+		cifs_put_tlink(tlink);
+		return ERR_PTR(-EACCES);
+	}
+
+	return tlink;
+}
+
+/*
+ * periodic workqueue job that scans tcon_tree for a superblock and closes
+ * out tcons.
+ */
+static void
+cifs_prune_tlinks(struct work_struct *work)
+{
+	struct cifs_sb_info *cifs_sb = container_of(work, struct cifs_sb_info,
+						    prune_tlinks.work);
+	struct rb_root *root = &cifs_sb->tlink_tree;
+	struct rb_node *node;
+	struct rb_node *tmp;
+	struct tcon_link *tlink;
+
+	/*
+	 * Because we drop the spinlock in the loop in order to put the tlink
+	 * it's not guarded against removal of links from the tree. The only
+	 * places that remove entries from the tree are this function and
+	 * umounts. Because this function is non-reentrant and is canceled
+	 * before umount can proceed, this is safe.
+	 */
+	spin_lock(&cifs_sb->tlink_tree_lock);
+	node = rb_first(root);
+	while (node != NULL) {
+		tmp = node;
+		node = rb_next(tmp);
+		tlink = rb_entry(tmp, struct tcon_link, tl_rbnode);
+
+		if (test_bit(TCON_LINK_MASTER, &tlink->tl_flags) ||
+		    atomic_read(&tlink->tl_count) != 0 ||
+		    time_after(tlink->tl_time + TLINK_IDLE_EXPIRE, jiffies))
+			continue;
+
+		cifs_get_tlink(tlink);
+		clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
+		rb_erase(tmp, root);
+
+		spin_unlock(&cifs_sb->tlink_tree_lock);
+		cifs_put_tlink(tlink);
+		spin_lock(&cifs_sb->tlink_tree_lock);
+	}
+	spin_unlock(&cifs_sb->tlink_tree_lock);
+
+	queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
+				TLINK_IDLE_EXPIRE);
+}
+
+#ifdef CONFIG_CIFS_DFS_UPCALL
+/* Update dfs referral path of superblock */
+static int update_server_fullpath(struct TCP_Server_Info *server, struct cifs_sb_info *cifs_sb,
+				  const char *target)
+{
+	int rc = 0;
+	size_t len = strlen(target);
+	char *refpath, *npath;
+
+	if (unlikely(len < 2 || *target != '\\'))
+		return -EINVAL;
+
+	if (target[1] == '\\') {
+		len += 1;
+		refpath = kmalloc(len, GFP_KERNEL);
+		if (!refpath)
+			return -ENOMEM;
+
+		scnprintf(refpath, len, "%s", target);
+	} else {
+		len += sizeof("\\");
+		refpath = kmalloc(len, GFP_KERNEL);
+		if (!refpath)
+			return -ENOMEM;
+
+		scnprintf(refpath, len, "\\%s", target);
+	}
+
+	npath = dfs_cache_canonical_path(refpath, cifs_sb->local_nls, cifs_remap(cifs_sb));
+	kfree(refpath);
+
+	if (IS_ERR(npath)) {
+		rc = PTR_ERR(npath);
+	} else {
+		mutex_lock(&server->refpath_lock);
+		kfree(server->leaf_fullpath);
+		server->leaf_fullpath = npath;
+		mutex_unlock(&server->refpath_lock);
+		server->current_fullpath = server->leaf_fullpath;
+	}
+	return rc;
+}
+
+static int target_share_matches_server(struct TCP_Server_Info *server, const char *tcp_host,
+				       size_t tcp_host_len, char *share, bool *target_match)
+{
+	int rc = 0;
+	const char *dfs_host;
+	size_t dfs_host_len;
+
+	*target_match = true;
+	extract_unc_hostname(share, &dfs_host, &dfs_host_len);
+
+	/* Check if hostnames or addresses match */
+	if (dfs_host_len != tcp_host_len || strncasecmp(dfs_host, tcp_host, dfs_host_len) != 0) {
+		cifs_dbg(FYI, "%s: %.*s doesn't match %.*s\n", __func__, (int)dfs_host_len,
+			 dfs_host, (int)tcp_host_len, tcp_host);
+		rc = match_target_ip(server, dfs_host, dfs_host_len, target_match);
+		if (rc)
+			cifs_dbg(VFS, "%s: failed to match target ip: %d\n", __func__, rc);
+	}
+	return rc;
+}
+
+static int __tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *tcon,
+				     struct cifs_sb_info *cifs_sb, char *tree, bool islink,
+				     struct dfs_cache_tgt_list *tl)
+{
+	int rc;
+	struct TCP_Server_Info *server = tcon->ses->server;
+	const struct smb_version_operations *ops = server->ops;
+	struct cifs_tcon *ipc = tcon->ses->tcon_ipc;
+	char *share = NULL, *prefix = NULL;
+	const char *tcp_host;
+	size_t tcp_host_len;
+	struct dfs_cache_tgt_iterator *tit;
+	bool target_match;
+
+	extract_unc_hostname(server->hostname, &tcp_host, &tcp_host_len);
+
+	tit = dfs_cache_get_tgt_iterator(tl);
+	if (!tit) {
+		rc = -ENOENT;
+		goto out;
+	}
+
+	/* Try to tree connect to all dfs targets */
+	for (; tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
+		const char *target = dfs_cache_get_tgt_name(tit);
+		struct dfs_cache_tgt_list ntl = DFS_CACHE_TGT_LIST_INIT(ntl);
+
+		kfree(share);
+		kfree(prefix);
+		share = prefix = NULL;
+
+		/* Check if share matches with tcp ses */
+		rc = dfs_cache_get_tgt_share(server->current_fullpath + 1, tit, &share, &prefix);
+		if (rc) {
+			cifs_dbg(VFS, "%s: failed to parse target share: %d\n", __func__, rc);
+			break;
+		}
+
+		rc = target_share_matches_server(server, tcp_host, tcp_host_len, share,
+						 &target_match);
+		if (rc)
+			break;
+		if (!target_match) {
+			rc = -EHOSTUNREACH;
+			continue;
+		}
+
+		if (ipc->need_reconnect) {
+			scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
+			rc = ops->tree_connect(xid, ipc->ses, tree, ipc, cifs_sb->local_nls);
+			if (rc)
+				break;
+		}
+
+		scnprintf(tree, MAX_TREE_SIZE, "\\%s", share);
+		if (!islink) {
+			rc = ops->tree_connect(xid, tcon->ses, tree, tcon, cifs_sb->local_nls);
+			break;
+		}
+		/*
+		 * If no dfs referrals were returned from link target, then just do a TREE_CONNECT
+		 * to it.  Otherwise, cache the dfs referral and then mark current tcp ses for
+		 * reconnect so either the demultiplex thread or the echo worker will reconnect to
+		 * newly resolved target.
+		 */
+		if (dfs_cache_find(xid, tcon->ses, cifs_sb->local_nls, cifs_remap(cifs_sb), target,
+				   NULL, &ntl)) {
+			rc = ops->tree_connect(xid, tcon->ses, tree, tcon, cifs_sb->local_nls);
+			if (rc)
+				continue;
+			rc = dfs_cache_noreq_update_tgthint(server->current_fullpath + 1, tit);
+			if (!rc)
+				rc = cifs_update_super_prepath(cifs_sb, prefix);
+		} else {
+			/* Target is another dfs share */
+			rc = update_server_fullpath(server, cifs_sb, target);
+			dfs_cache_free_tgts(tl);
+
+			if (!rc) {
+				rc = -EREMOTE;
+				list_replace_init(&ntl.tl_list, &tl->tl_list);
+			} else
+				dfs_cache_free_tgts(&ntl);
+		}
+		break;
+	}
+
+out:
+	kfree(share);
+	kfree(prefix);
+
+	return rc;
+}
+
+static int tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *tcon,
+				   struct cifs_sb_info *cifs_sb, char *tree, bool islink,
+				   struct dfs_cache_tgt_list *tl)
+{
+	int rc;
+	int num_links = 0;
+	struct TCP_Server_Info *server = tcon->ses->server;
+
+	do {
+		rc = __tree_connect_dfs_target(xid, tcon, cifs_sb, tree, islink, tl);
+		if (!rc || rc != -EREMOTE)
+			break;
+	} while (rc = -ELOOP, ++num_links < MAX_NESTED_LINKS);
+	/*
+	 * If we couldn't tree connect to any targets from last referral path, then retry from
+	 * original referral path.
+	 */
+	if (rc && server->current_fullpath != server->origin_fullpath) {
+		server->current_fullpath = server->origin_fullpath;
+		cifs_signal_cifsd_for_reconnect(server, true);
+	}
+
+	dfs_cache_free_tgts(tl);
+	return rc;
+}
+
+int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
+{
+	int rc;
+	struct TCP_Server_Info *server = tcon->ses->server;
+	const struct smb_version_operations *ops = server->ops;
+	struct super_block *sb = NULL;
+	struct cifs_sb_info *cifs_sb;
+	struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
+	char *tree;
+	struct dfs_info3_param ref = {0};
+
+	/* only send once per connect */
+	spin_lock(&tcon->tc_lock);
+	if (tcon->ses->ses_status != SES_GOOD ||
+	    (tcon->status != TID_NEW &&
+	    tcon->status != TID_NEED_TCON)) {
+		spin_unlock(&tcon->tc_lock);
+		return 0;
+	}
+	tcon->status = TID_IN_TCON;
+	spin_unlock(&tcon->tc_lock);
+
+	tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
+	if (!tree) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	if (tcon->ipc) {
+		scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
+		rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
+		goto out;
+	}
+
+	sb = cifs_get_tcp_super(server);
+	if (IS_ERR(sb)) {
+		rc = PTR_ERR(sb);
+		cifs_dbg(VFS, "%s: could not find superblock: %d\n", __func__, rc);
+		goto out;
+	}
+
+	cifs_sb = CIFS_SB(sb);
+
+	/* If it is not dfs or there was no cached dfs referral, then reconnect to same share */
+	if (!server->current_fullpath ||
+	    dfs_cache_noreq_find(server->current_fullpath + 1, &ref, &tl)) {
+		rc = ops->tree_connect(xid, tcon->ses, tcon->tree_name, tcon, cifs_sb->local_nls);
+		goto out;
+	}
+
+	rc = tree_connect_dfs_target(xid, tcon, cifs_sb, tree, ref.server_type == DFS_TYPE_LINK,
+				     &tl);
+	free_dfs_info_param(&ref);
+
+out:
+	kfree(tree);
+	cifs_put_tcp_super(sb);
+
+	if (rc) {
+		spin_lock(&tcon->tc_lock);
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_NEED_TCON;
+		spin_unlock(&tcon->tc_lock);
+	} else {
+		spin_lock(&tcon->tc_lock);
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_GOOD;
+		spin_unlock(&tcon->tc_lock);
+		tcon->need_reconnect = false;
+	}
+
+	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 */
+	spin_lock(&tcon->tc_lock);
+	if (tcon->ses->ses_status != SES_GOOD ||
+	    (tcon->status != TID_NEW &&
+	    tcon->status != TID_NEED_TCON)) {
+		spin_unlock(&tcon->tc_lock);
+		return 0;
+	}
+	tcon->status = TID_IN_TCON;
+	spin_unlock(&tcon->tc_lock);
+
+	rc = ops->tree_connect(xid, tcon->ses, tcon->tree_name, tcon, nlsc);
+	if (rc) {
+		spin_lock(&tcon->tc_lock);
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_NEED_TCON;
+		spin_unlock(&tcon->tc_lock);
+	} else {
+		spin_lock(&tcon->tc_lock);
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_GOOD;
+		tcon->need_reconnect = false;
+		spin_unlock(&tcon->tc_lock);
+	}
+
+	return rc;
+}
+#endif