Merge tag '5.16-rc-part2-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull more cifs updates from Steve French:

- improvements to reconnect and multichannel

- a performance improvement (additional use of SMB3 compounding)

- DFS code cleanup and improvements

- various trivial Coverity fixes

- two fscache fixes

- an fsync fix

* tag '5.16-rc-part2-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: (23 commits)
cifs: do not duplicate fscache cookie for secondary channels
cifs: connect individual channel servers to primary channel server
cifs: protect session channel fields with chan_lock
cifs: do not negotiate session if session already exists
smb3: do not setup the fscache_super_cookie until fsinfo initialized
cifs: fix potential use-after-free bugs
cifs: fix memory leak of smb3_fs_context_dup::server_hostname
smb3: add additional null check in SMB311_posix_mkdir
cifs: release lock earlier in dequeue_mid error case
smb3: add additional null check in SMB2_tcon
smb3: add additional null check in SMB2_open
smb3: add additional null check in SMB2_ioctl
smb3: remove trivial dfs compile warning
cifs: support nested dfs links over reconnect
smb3: do not error on fsync when readonly
cifs: for compound requests, use open handle if possible
cifs: set a minimum of 120s for next dns resolution
cifs: split out dfs code from cifs_reconnect()
cifs: convert list_for_each to entry variant
cifs: introduce new helper for cifs_reconnect()
...

fs/cifs/cifs_debug.c

···
 	c = 0;
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
-		if (server->is_channel)
+		/* channel info will be printed as a part of sessions below */
+		if (CIFS_SERVER_IS_CHAN(server))
 			continue;
 
 		c++;
···
 			seq_printf(m, " signed");
 		if (server->posix_ext_supported)
 			seq_printf(m, " posix");
+		if (server->nosharesock)
+			seq_printf(m, " nosharesock");
 
 		if (server->rdma)
 			seq_printf(m, "\nRDMA ");
···
 				   from_kuid(&init_user_ns, ses->linux_uid),
 				   from_kuid(&init_user_ns, ses->cred_uid));
 
+			spin_lock(&ses->chan_lock);
 			if (ses->chan_count > 1) {
 				seq_printf(m, "\n\n\tExtra Channels: %zu ",
 					   ses->chan_count-1);
 				for (j = 1; j < ses->chan_count; j++)
 					cifs_dump_channel(m, j, &ses->chans[j]);
 			}
+			spin_unlock(&ses->chan_lock);
 
 			seq_puts(m, "\n\n\tShares: ");
 			j = 0;

fs/cifs/cifs_dfs_ref.c

···
 static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
 {
 	struct cifs_sb_info *cifs_sb;
-	struct cifs_ses *ses;
-	struct cifs_tcon *tcon;
 	void *page;
-	char *full_path, *root_path;
-	unsigned int xid;
-	int rc;
+	char *full_path;
 	struct vfsmount *mnt;
 
 	cifs_dbg(FYI, "in %s\n", __func__);
···
 	 * the double backslashes usually used in the UNC. This function
 	 * gives us the latter, so we must adjust the result.
 	 */
-	mnt = ERR_PTR(-ENOMEM);
-
 	cifs_sb = CIFS_SB(mntpt->d_sb);
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) {
 		mnt = ERR_PTR(-EREMOTE);
···
 	}
 
 	convert_delimiter(full_path, '\\');
-
 	cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
 
-	if (!cifs_sb_master_tlink(cifs_sb)) {
-		cifs_dbg(FYI, "%s: master tlink is NULL\n", __func__);
-		goto free_full_path;
-	}
-
-	tcon = cifs_sb_master_tcon(cifs_sb);
-	if (!tcon) {
-		cifs_dbg(FYI, "%s: master tcon is NULL\n", __func__);
-		goto free_full_path;
-	}
-
-	root_path = kstrdup(tcon->treeName, GFP_KERNEL);
-	if (!root_path) {
-		mnt = ERR_PTR(-ENOMEM);
-		goto free_full_path;
-	}
-	cifs_dbg(FYI, "%s: root path: %s\n", __func__, root_path);
-
-	ses = tcon->ses;
-	xid = get_xid();
-
-	/*
-	 * If DFS root has been expired, then unconditionally fetch it again to
-	 * refresh DFS referral cache.
-	 */
-	rc = dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
-			    root_path + 1, NULL, NULL);
-	if (!rc) {
-		rc = dfs_cache_find(xid, ses, cifs_sb->local_nls,
-				    cifs_remap(cifs_sb), full_path + 1,
-				    NULL, NULL);
-	}
-
-	free_xid(xid);
-
-	if (rc) {
-		mnt = ERR_PTR(rc);
-		goto free_root_path;
-	}
-	/*
-	 * OK - we were able to get and cache a referral for @full_path.
-	 *
-	 * Now, pass it down to cifs_mount() and it will retry every available
-	 * node server in case of failures - no need to do it here.
-	 */
 	mnt = cifs_dfs_do_mount(mntpt, cifs_sb, full_path);
-	cifs_dbg(FYI, "%s: cifs_dfs_do_mount:%s , mnt:%p\n", __func__,
-		 full_path + 1, mnt);
+	cifs_dbg(FYI, "%s: cifs_dfs_do_mount:%s , mnt:%p\n", __func__, full_path + 1, mnt);
 
-free_root_path:
-	kfree(root_path);
 free_full_path:
 	free_dentry_path(page);
 cdda_exit:

fs/cifs/cifs_fs_sb.h

···
 	/* only used when CIFS_MOUNT_USE_PREFIX_PATH is set */
 	char *prepath;
 
-	/*
-	 * Canonical DFS path initially provided by the mount call. We might connect to something
-	 * different via DFS but we want to keep it to do failover properly.
-	 */
-	char *origin_fullpath; /* \\HOST\SHARE\[OPTIONAL PATH] */
 	/* randomly generated 128-bit number for indexing dfs mount groups in referral cache */
 	uuid_t dfs_mount_id;
 	/*

fs/cifs/cifsglob.h

···
 #include <linux/slab.h>
 #include <linux/mempool.h>
 #include <linux/workqueue.h>
+#include <linux/utsname.h>
 #include "cifs_fs_sb.h"
 #include "cifsacl.h"
 #include <crypto/internal/hash.h>
···
 #define SMB_ECHO_INTERVAL_MAX 600
 #define SMB_ECHO_INTERVAL_DEFAULT 60
 
-/* dns resolution interval in seconds */
+/* dns resolution intervals in seconds */
+#define SMB_DNS_RESOLVE_INTERVAL_MIN     120
 #define SMB_DNS_RESOLVE_INTERVAL_DEFAULT 600
 
 /* maximum number of PDUs in one compound */
···
 #ifndef XATTR_DOS_ATTRIB
 #define XATTR_DOS_ATTRIB "user.DOSATTRIB"
 #endif
+
+#define CIFS_MAX_WORKSTATION_LEN  (__NEW_UTS_LEN + 1)  /* reasonable max for client */
 
 /*
  * CIFS vfs client Status information (based on what we know.)
···
 	struct list_head pending_mid_q;
 	bool noblocksnd;		/* use blocking sendmsg */
 	bool noautotune;		/* do not autotune send buf sizes */
+	bool nosharesock;
 	bool tcp_nodelay;
 	unsigned int credits;  /* send no more requests at once */
 	unsigned int max_credits; /* can override large 32000 default at mnt */
···
 	 */
 	int nr_targets;
 	bool noblockcnt; /* use non-blocking connect() */
-	bool is_channel; /* if a session channel */
+
+	/*
+	 * If this is a session channel,
+	 * primary_server holds the ref-counted
+	 * pointer to primary channel connection for the session.
+	 */
+#define CIFS_SERVER_IS_CHAN(server)	(!!(server)->primary_server)
+	struct TCP_Server_Info *primary_server;
+
 #ifdef CONFIG_CIFS_SWN_UPCALL
 	bool use_swn_dstaddr;
 	struct sockaddr_storage swn_dstaddr;
 #endif
 #ifdef CONFIG_CIFS_DFS_UPCALL
 	bool is_dfs_conn; /* if a dfs connection */
+	struct mutex refpath_lock; /* protects leaf_fullpath */
+	/*
+	 * Canonical DFS full paths that were used to chase referrals in mount and reconnect.
+	 *
+	 * origin_fullpath: first or original referral path
+	 * leaf_fullpath: last referral path (might be changed due to nested links in reconnect)
+	 *
+	 * current_fullpath: pointer to either origin_fullpath or leaf_fullpath
+	 * NOTE: cannot be accessed outside cifs_reconnect() and smb2_reconnect()
+	 *
+	 * format: \\HOST\SHARE\[OPTIONAL PATH]
+	 */
+	char *origin_fullpath, *leaf_fullpath, *current_fullpath;
 #endif
 };
 
···
 				   and after mount option parsing we fill it */
 	char *domainName;
 	char *password;
+	char *workstation_name;
 	struct session_key auth_key;
 	struct ntlmssp_auth *ntlmssp; /* ciphertext, flags, server challenge */
 	enum securityEnum sectype; /* what security flavor was specified? */
···
 	 * iface_lock should be taken when accessing any of these fields
 	 */
 	spinlock_t iface_lock;
+	/* ========= begin: protected by iface_lock ======== */
 	struct cifs_server_iface *iface_list;
 	size_t iface_count;
 	unsigned long iface_last_update; /* jiffies */
+	/* ========= end: protected by iface_lock ======== */
 
+	spinlock_t chan_lock;
+	/* ========= begin: protected by chan_lock ======== */
 #define CIFS_MAX_CHANNELS 16
 	struct cifs_chan chans[CIFS_MAX_CHANNELS];
 	struct cifs_chan *binding_chan;
 	size_t chan_count;
 	size_t chan_max;
 	atomic_t chan_seq; /* round robin state */
+	/* ========= end: protected by chan_lock ======== */
 };
 
 /*
···
 	struct cached_fid crfid; /* Cached root fid */
 	/* BB add field for back pointer to sb struct(s)? */
 #ifdef CONFIG_CIFS_DFS_UPCALL
-	char *dfs_path; /* canonical DFS path */
 	struct list_head ulist; /* cache update list */
 #endif
 };
···
 		return false;
 	return is_smb1_server(tcon->ses->server) ? tcon->Flags & SMB_SHARE_IS_IN_DFS :
 		tcon->share_flags & (SHI1005_FLAGS_DFS | SHI1005_FLAGS_DFS_ROOT);
+}
+
+static inline bool cifs_is_referral_server(struct cifs_tcon *tcon,
+					   const struct dfs_info3_param *ref)
+{
+	/*
+	 * Check if all targets are capable of handling DFS referrals as per
+	 * MS-DFSC 2.2.4 RESP_GET_DFS_REFERRAL.
+	 */
+	return is_tcon_dfs(tcon) || (ref && (ref->flags & DFSREF_REFERRAL_SERVER));
 }
 
 #endif	/* _CIFS_GLOB_H */

fs/cifs/cifsproto.h

···
 
 extern void cifs_close_deferred_file_under_dentry(struct cifs_tcon *cifs_tcon,
 				const char *path);
-
-extern struct TCP_Server_Info *cifs_get_tcp_session(struct smb3_fs_context *ctx);
+extern struct TCP_Server_Info *
+cifs_get_tcp_session(struct smb3_fs_context *ctx,
+		     struct TCP_Server_Info *primary_server);
 extern void cifs_put_tcp_session(struct TCP_Server_Info *server,
 				 int from_reconnect);
 extern void cifs_put_tcon(struct cifs_tcon *tcon);
···
 
 struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server);
 void cifs_put_tcp_super(struct super_block *sb);
-int update_super_prepath(struct cifs_tcon *tcon, char *prefix);
+int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix);
 char *extract_hostname(const char *unc);
 char *extract_sharename(const char *unc);
 
···
 	else
 		return options;
 }
+
+struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon);
+void cifs_put_tcon_super(struct super_block *sb);
 
 #endif			/* _CIFSPROTO_H */

fs/cifs/connect.c

···
 /* Drop the connection to not overload the server */
 #define NUM_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);
···
 			 * To make sure we don't use the cached entry, retry 1s
 			 * after expiry.
 			 */
-			ttl = (expiry - now + 1);
+			ttl = max_t(unsigned long, expiry - now, SMB_DNS_RESOLVE_INTERVAL_MIN) + 1;
 	}
 	rc = !rc ? -1 : 0;
 
···
 	mutex_unlock(&server->srv_mutex);
 }
 
-#ifdef CONFIG_CIFS_DFS_UPCALL
-/* These functions must be called with server->srv_mutex held */
-static void reconn_set_next_dfs_target(struct TCP_Server_Info *server,
-				       struct cifs_sb_info *cifs_sb,
-				       struct dfs_cache_tgt_list *tgt_list,
-				       struct dfs_cache_tgt_iterator **tgt_it)
-{
-	const char *name;
-	int rc;
-
-	if (!cifs_sb || !cifs_sb->origin_fullpath)
-		return;
-
-	if (!*tgt_it) {
-		*tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
-	} else {
-		*tgt_it = dfs_cache_get_next_tgt(tgt_list, *tgt_it);
-		if (!*tgt_it)
-			*tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
-	}
-
-	cifs_dbg(FYI, "%s: UNC: %s\n", __func__, cifs_sb->origin_fullpath);
-
-	name = dfs_cache_get_tgt_name(*tgt_it);
-
-	kfree(server->hostname);
-
-	server->hostname = extract_hostname(name);
-	if (IS_ERR(server->hostname)) {
-		cifs_dbg(FYI,
-			 "%s: failed to extract hostname from target: %ld\n",
-			 __func__, PTR_ERR(server->hostname));
-		return;
-	}
-
-	rc = reconn_set_ipaddr_from_hostname(server);
-	if (rc) {
-		cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
-			 __func__, rc);
-	}
-}
-
-static inline int reconn_setup_dfs_targets(struct cifs_sb_info *cifs_sb,
-					   struct dfs_cache_tgt_list *tl)
-{
-	if (!cifs_sb->origin_fullpath)
-		return -EOPNOTSUPP;
-	return dfs_cache_noreq_find(cifs_sb->origin_fullpath + 1, NULL, tl);
-}
-#endif
-
-/*
- * cifs tcp session reconnection
+/**
+ * Mark all sessions and tcons for reconnect.
  *
- * 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)
+ * @server needs to be previously set to CifsNeedReconnect.
  */
-int
-cifs_reconnect(struct TCP_Server_Info *server)
+static void cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server)
 {
-	int rc = 0;
-	struct list_head *tmp, *tmp2;
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon;
-	struct mid_q_entry *mid_entry;
+	struct mid_q_entry *mid, *nmid;
 	struct list_head retry_list;
-#ifdef CONFIG_CIFS_DFS_UPCALL
-	struct super_block *sb = NULL;
-	struct cifs_sb_info *cifs_sb = NULL;
-	struct dfs_cache_tgt_list tgt_list = DFS_CACHE_TGT_LIST_INIT(tgt_list);
-	struct dfs_cache_tgt_iterator *tgt_it = NULL;
-#endif
+	struct TCP_Server_Info *pserver;
 
-	spin_lock(&GlobalMid_Lock);
-	server->nr_targets = 1;
-#ifdef CONFIG_CIFS_DFS_UPCALL
-	spin_unlock(&GlobalMid_Lock);
-	sb = cifs_get_tcp_super(server);
-	if (IS_ERR(sb)) {
-		rc = PTR_ERR(sb);
-		cifs_dbg(FYI, "%s: will not do DFS failover: rc = %d\n",
-			 __func__, rc);
-		sb = NULL;
-	} else {
-		cifs_sb = CIFS_SB(sb);
-		rc = reconn_setup_dfs_targets(cifs_sb, &tgt_list);
-		if (rc) {
-			cifs_sb = NULL;
-			if (rc != -EOPNOTSUPP) {
-				cifs_server_dbg(VFS, "%s: no target servers for DFS failover\n",
-						__func__);
-			}
-		} else {
-			server->nr_targets = dfs_cache_get_nr_tgts(&tgt_list);
-		}
-	}
-	cifs_dbg(FYI, "%s: will retry %d target(s)\n", __func__,
-		 server->nr_targets);
-	spin_lock(&GlobalMid_Lock);
-#endif
-	if (server->tcpStatus == CifsExiting) {
-		/* the demux thread will exit normally
-		next time through the loop */
-		spin_unlock(&GlobalMid_Lock);
-#ifdef CONFIG_CIFS_DFS_UPCALL
-		dfs_cache_free_tgts(&tgt_list);
-		cifs_put_tcp_super(sb);
-#endif
-		wake_up(&server->response_q);
-		return rc;
-	} else
-		server->tcpStatus = CifsNeedReconnect;
-	spin_unlock(&GlobalMid_Lock);
 	server->maxBuf = 0;
 	server->max_read = 0;
 
 	cifs_dbg(FYI, "Mark tcp session as need reconnect\n");
 	trace_smb3_reconnect(server->CurrentMid, server->conn_id, server->hostname);
+	/*
+	 * 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 sessions and tcons for reconnect\n", __func__);
 
-	/* 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 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(tmp, &server->smb_ses_list) {
-		ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 		ses->need_reconnect = true;
-		list_for_each(tmp2, &ses->tcon_list) {
-			tcon = list_entry(tmp2, struct cifs_tcon, tcon_list);
+		list_for_each_entry(tcon, &ses->tcon_list, tcon_list)
 			tcon->need_reconnect = true;
-		}
 		if (ses->tcon_ipc)
 			ses->tcon_ipc->need_reconnect = true;
 	}
···
 	cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
 	mutex_lock(&server->srv_mutex);
 	if (server->ssocket) {
-		cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n",
-			 server->ssocket->state, server->ssocket->flags);
+		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);
+		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;
 	}
···
 	INIT_LIST_HEAD(&retry_list);
 	cifs_dbg(FYI, "%s: moving mids to private list\n", __func__);
 	spin_lock(&GlobalMid_Lock);
-	list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
-		mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
-		kref_get(&mid_entry->refcount);
-		if (mid_entry->mid_state == MID_REQUEST_SUBMITTED)
-			mid_entry->mid_state = MID_RETRY_NEEDED;
-		list_move(&mid_entry->qhead, &retry_list);
-		mid_entry->mid_flags |= MID_DELETED;
+	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(&GlobalMid_Lock);
 	mutex_unlock(&server->srv_mutex);
 
 	cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
-	list_for_each_safe(tmp, tmp2, &retry_list) {
-		mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
-		list_del_init(&mid_entry->qhead);
-		mid_entry->callback(mid_entry);
-		cifs_mid_q_entry_release(mid_entry);
+	list_for_each_entry_safe(mid, nmid, &retry_list, qhead) {
+		list_del_init(&mid->qhead);
+		mid->callback(mid);
+		cifs_mid_q_entry_release(mid);
 	}
 
 	if (cifs_rdma_enabled(server)) {
···
 		smbd_destroy(server);
 		mutex_unlock(&server->srv_mutex);
 	}
+}
+
+static bool cifs_tcp_ses_needs_reconnect(struct TCP_Server_Info *server, int num_targets)
+{
+	spin_lock(&GlobalMid_Lock);
+	server->nr_targets = num_targets;
+	if (server->tcpStatus == CifsExiting) {
+		/* the demux thread will exit normally next time through the loop */
+		spin_unlock(&GlobalMid_Lock);
+		wake_up(&server->response_q);
+		return false;
+	}
+	server->tcpStatus = CifsNeedReconnect;
+	spin_unlock(&GlobalMid_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)
+ */
+static int __cifs_reconnect(struct TCP_Server_Info *server)
+{
+	int rc = 0;
+
+	if (!cifs_tcp_ses_needs_reconnect(server, 1))
+		return 0;
+
+	cifs_mark_tcp_ses_conns_for_reconnect(server);
 
 	do {
 		try_to_freeze();
-
 		mutex_lock(&server->srv_mutex);
 
-
 		if (!cifs_swn_set_server_dstaddr(server)) {
-#ifdef CONFIG_CIFS_DFS_UPCALL
-		if (cifs_sb && cifs_sb->origin_fullpath)
-			/*
-			 * Set up next DFS target server (if any) for reconnect. If DFS
-			 * feature is disabled, then we will retry last server we
-			 * connected to before.
-			 */
-			reconn_set_next_dfs_target(server, cifs_sb, &tgt_list, &tgt_it);
-		else {
-#endif
-			/*
-			 * Resolve the hostname again to make sure that IP address is up-to-date.
-			 */
+			/* 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);
-			}
-
-#ifdef CONFIG_CIFS_DFS_UPCALL
-		}
-#endif
-
-
+			cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
 		}
 
 		if (cifs_rdma_enabled(server))
···
 		else
 			rc = generic_ip_connect(server);
 		if (rc) {
-			cifs_dbg(FYI, "reconnect error %d\n", rc);
 			mutex_unlock(&server->srv_mutex);
+			cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
 			msleep(3000);
 		} else {
 			atomic_inc(&tcpSesReconnectCount);
···
 		}
 	} while (server->tcpStatus == CifsNeedReconnect);
 
-#ifdef CONFIG_CIFS_DFS_UPCALL
-	if (tgt_it) {
-		rc = dfs_cache_noreq_update_tgthint(cifs_sb->origin_fullpath + 1,
-						    tgt_it);
-		if (rc) {
-			cifs_server_dbg(VFS, "%s: failed to update DFS target hint: rc = %d\n",
-				 __func__, rc);
-		}
-		dfs_cache_free_tgts(&tgt_list);
-	}
-
-	cifs_put_tcp_super(sb);
-#endif
 	if (server->tcpStatus == CifsNeedNegotiate)
 		mod_delayed_work(cifsiod_wq, &server->echo, 0);
 
 	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)) {
+				kfree(server->hostname);
+				server->hostname = hostname;
+			} 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;
+
+	cifs_mark_tcp_ses_conns_for_reconnect(server);
+
+	do {
+		try_to_freeze();
+		mutex_lock(&server->srv_mutex);
+
+		rc = reconnect_target_unlocked(server, &tl, &target_hint);
+		if (rc) {
+			/* Failed to reconnect socket */
+			mutex_unlock(&server->srv_mutex);
+			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(&GlobalMid_Lock);
+		if (server->tcpStatus != CifsExiting)
+			server->tcpStatus = CifsNeedNegotiate;
+		spin_unlock(&GlobalMid_Lock);
+		cifs_swn_reset_server_dstaddr(server);
+		mutex_unlock(&server->srv_mutex);
+	} 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 */
+	if (server->tcpStatus == CifsNeedNegotiate)
+		mod_delayed_work(cifsiod_wq, &server->echo, 0);
+
+	wake_up(&server->response_q);
+	return rc;
+}
+
+int cifs_reconnect(struct TCP_Server_Info *server)
+{
+	/* If tcp session is not an dfs connection, then reconnect to last target server */
+	spin_lock(&cifs_tcp_ses_lock);
+	if (!server->is_dfs_conn || !server->origin_fullpath || !server->leaf_fullpath) {
+		spin_unlock(&cifs_tcp_ses_lock);
+		return __cifs_reconnect(server);
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	return reconnect_dfs_server(server);
+}
+#else
+int cifs_reconnect(struct TCP_Server_Info *server)
+{
+	return __cifs_reconnect(server);
+}
+#endif
 
 static void
 cifs_echo_request(struct work_struct *work)
···
 	 * Trying to handle/dequeue a mid after the send_recv()
 	 * function has finished processing it is a bug.
 	 */
-	if (mid->mid_flags & MID_DELETED)
+	if (mid->mid_flags & MID_DELETED) {
+		spin_unlock(&GlobalMid_Lock);
 		pr_warn_once("trying to dequeue a deleted mid\n");
-	else {
+	} else {
 		list_del_init(&mid->qhead);
 		mid->mid_flags |= MID_DELETED;
+		spin_unlock(&GlobalMid_Lock);
 	}
-	spin_unlock(&GlobalMid_Lock);
 }
 
 static unsigned int
···
 		 */
 	}
 
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	kfree(server->origin_fullpath);
+	kfree(server->leaf_fullpath);
+#endif
 	kfree(server);
 
 	length = atomic_dec_return(&tcpSesAllocCount);
···
 {
 	struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
 
-	if (ctx->nosharesock)
+	if (ctx->nosharesock) {
+		server->nosharesock = true;
+		return 0;
+	}
+
+	/* this server does not share socket */
+	if (server->nosharesock)
 		return 0;
 
 	/* If multidialect negotiation see if existing sessions match one */
···
 		 * Skip ses channels since they're only handled in lower layers
 		 * (e.g. cifs_send_recv).
 		 */
-		if (server->is_channel || !match_server(server, ctx))
+		if (CIFS_SERVER_IS_CHAN(server) || !match_server(server, ctx))
 			continue;
 
 		++server->srv_count;
···
 	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);
 
···
 	spin_unlock(&GlobalMid_Lock);
 
 	cifs_crypto_secmech_release(server);
-	cifs_fscache_release_client_cookie(server);
+
+	/* fscache server cookies are based on primary channel only */
+	if (!CIFS_SERVER_IS_CHAN(server))
+		cifs_fscache_release_client_cookie(server);
 
 	kfree(server->session_key.response);
 	server->session_key.response = NULL;
···
 }
 
 struct TCP_Server_Info *
-cifs_get_tcp_session(struct smb3_fs_context *ctx)
+cifs_get_tcp_session(struct smb3_fs_context *ctx,
+		     struct TCP_Server_Info *primary_server)
 {
 	struct TCP_Server_Info *tcp_ses = NULL;
 	int rc;
···
 	tcp_ses->in_flight = 0;
 	tcp_ses->max_in_flight = 0;
 	tcp_ses->credits = 1;
+	if (primary_server) {
+		++primary_server->srv_count;
+		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);
···
 	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,
···
 	list_add(&tcp_ses->tcp_ses_list, &cifs_tcp_ses_list);
 	spin_unlock(&cifs_tcp_ses_lock);
 
-	cifs_fscache_get_client_cookie(tcp_ses);
+	/* fscache server cookies are based on primary channel only */
+	if (!CIFS_SERVER_IS_CHAN(tcp_ses))
+		cifs_fscache_get_client_cookie(tcp_ses);
 
 	/* queue echo request delayed work */
 	queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
···
 
 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);
···
 	 * If an existing session is limited to less channels than
 	 * requested, it should not be reused
 	 */
-	if (ses->chan_max < ctx->max_channels)
+	spin_lock(&ses->chan_lock);
+	if (ses->chan_max < ctx->max_channels) {
+		spin_unlock(&ses->chan_lock);
 		return 0;
+	}
+	spin_unlock(&ses->chan_lock);
 
 	switch (ses->sectype) {
 	case Kerberos:
···
 void cifs_put_smb_ses(struct cifs_ses *ses)
 {
 	unsigned int rc, xid;
+	unsigned int chan_count;
 	struct TCP_Server_Info *server = ses->server;
 	cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
 
···
 	list_del_init(&ses->smb_ses_list);
 	spin_unlock(&cifs_tcp_ses_lock);
 
+	spin_lock(&ses->chan_lock);
+	chan_count = ses->chan_count;
+	spin_unlock(&ses->chan_lock);
+
 	/* close any extra channels */
-	if (ses->chan_count > 1) {
+	if (chan_count > 1) {
 		int i;
 
-		for (i = 1; i < ses->chan_count; i++)
+		for (i = 1; i < chan_count; i++) {
+			/*
+			 * note: for now, we're okay accessing ses->chans
+			 * without chan_lock. But when chans can go away, we'll
+			 * need to introduce ref counting to make sure that chan
+			 * is not freed from under us.
+			 */
 			cifs_put_tcp_session(ses->chans[i].server, 0);
+			ses->chans[i].server = NULL;
+		}
 	}
 
 	sesInfoFree(ses);
···
 			 ses->status);
 
 		mutex_lock(&ses->session_mutex);
-		rc = cifs_negotiate_protocol(xid, ses);
-		if (rc) {
-			mutex_unlock(&ses->session_mutex);
-			/* problem -- put our ses reference */
-			cifs_put_smb_ses(ses);
-			free_xid(xid);
-			return ERR_PTR(rc);
-		}
 		if (ses->need_reconnect) {
 			cifs_dbg(FYI, "Session needs reconnect\n");
+
+			rc = cifs_negotiate_protocol(xid, ses);
+			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,
 						ctx->local_nls);
 			if (rc) {
···
 		if (!ses->domainName)
 			goto get_ses_fail;
 	}
+	if (ctx->workstation_name) {
+		ses->workstation_name = kstrdup(ctx->workstation_name,
+						GFP_KERNEL);
+		if (!ses->workstation_name)
+			goto get_ses_fail;
+	}
 	if (ctx->domainauto)
 		ses->domainAuto = ctx->domainauto;
 	ses->cred_uid = ctx->cred_uid;
···
 	mutex_lock(&ses->session_mutex);
 
 	/* 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;
+	spin_unlock(&ses->chan_lock);
 
 	rc = cifs_negotiate_protocol(xid, ses);
 	if (!rc)
···
 	spin_lock(&cifs_tcp_ses_lock);
 	list_add(&tcon->tcon_list, &ses->tcon_list);
 	spin_unlock(&cifs_tcp_ses_lock);
-
-	cifs_fscache_get_super_cookie(tcon);
 
 	return tcon;
 
···
 }
 
 /* Release all succeed connections */
-static inline void mount_put_conns(struct cifs_sb_info *cifs_sb,
-				   unsigned int xid,
-				   struct TCP_Server_Info *server,
-				   struct cifs_ses *ses, struct cifs_tcon *tcon)
+static inline void mount_put_conns(struct mount_ctx *mnt_ctx)
 {
 	int rc = 0;
 
-	if (tcon)
-		cifs_put_tcon(tcon);
-	else if (ses)
-		cifs_put_smb_ses(ses);
-	else if (server)
-		cifs_put_tcp_session(server, 0);
-	cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
-	free_xid(xid);
+	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 smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
-			   unsigned int *xid,
-			   struct TCP_Server_Info **nserver,
-			   struct cifs_ses **nses, struct cifs_tcon **ntcon)
+static int mount_get_conns(struct mount_ctx *mnt_ctx)
 {
 	int rc = 0;
-	struct TCP_Server_Info *server;
-	struct cifs_ses *ses;
-	struct cifs_tcon *tcon;
+	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;
 
-	*nserver = NULL;
-	*nses = NULL;
-	*ntcon = NULL;
-
-	*xid = get_xid();
+	xid = get_xid();
 
 	/* get a reference to a tcp session */
-	server = cifs_get_tcp_session(ctx);
+	server = cifs_get_tcp_session(ctx, NULL);
 	if (IS_ERR(server)) {
 		rc = PTR_ERR(server);
-		return rc;
+		server = NULL;
+		goto out;
 	}
-
-	*nserver = server;
 
 	/* get a reference to a SMB session */
 	ses = cifs_get_smb_ses(server, ctx);
 	if (IS_ERR(ses)) {
 		rc = PTR_ERR(ses);
-		return rc;
+		ses = NULL;
+		goto out;
 	}
-
-	*nses = ses;
 
 	if ((ctx->persistent == true) && (!(ses->server->capabilities &
 					    SMB2_GLOBAL_CAP_PERSISTENT_HANDLES))) {
 		cifs_server_dbg(VFS, "persistent handles not supported by server\n");
-		return -EOPNOTSUPP;
+		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);
-		return rc;
+		tcon = NULL;
+		goto out;
 	}
-
-	*ntcon = tcon;
 
 	/* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
 	if (tcon->posix_extensions)
···
 		 * reset of caps checks mount to see if unix extensions disabled
 		 * for just this mount.
 		 */
-		reset_cifs_unix_caps(*xid, tcon, cifs_sb, ctx);
+		reset_cifs_unix_caps(xid, tcon, cifs_sb, ctx);
 		if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
 		    (le64_to_cpu(tcon->fsUnixInfo.Capability) &
-		     CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP))
-			return -EACCES;
+		     CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)) {
+			rc = -EACCES;
+			goto out;
+		}
 	} else
 		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);
+		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, "read only mount of RW share\n");
 			/* no need to log a RW mount of a typical RW share */
 		}
+		/*
+		 * 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.
+		 */
+		cifs_fscache_get_super_cookie(tcon);
 	}
 
 	/*
···
 	    (cifs_sb->ctx->rsize > server->ops->negotiate_rsize(tcon, ctx)))
 		cifs_sb->ctx->rsize = server->ops->negotiate_rsize(tcon, ctx);
 
-	return 0;
+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,
···
 }
 
 #ifdef CONFIG_CIFS_DFS_UPCALL
-static int mount_get_dfs_conns(struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
-			       unsigned int *xid, struct TCP_Server_Info **nserver,
-			       struct cifs_ses **nses, struct cifs_tcon **ntcon)
+/* Get unique dfs connections */
+static int mount_get_dfs_conns(struct mount_ctx *mnt_ctx)
 {
 	int rc;
 
-	ctx->nosharesock = true;
-	rc = mount_get_conns(ctx, cifs_sb, xid, nserver, nses, ntcon);
-	if (*nserver) {
+	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(&cifs_tcp_ses_lock);
-		(*nserver)->is_dfs_conn = true;
+		mnt_ctx->server->is_dfs_conn = true;
 		spin_unlock(&cifs_tcp_ses_lock);
 	}
 	return rc;
···
 }
 
 /*
- * expand_dfs_referral - Perform a dfs referral query and update the cifs_sb
+ * expand_dfs_referral - Update cifs_sb from dfs referral path
  *
- * If a referral is found, cifs_sb->ctx->mount_options will be (re-)allocated
- * to a string containing updated options for the submount.  Otherwise it
- * will be left untouched.
- *
- * Returns the rc from get_dfs_path to the caller, which can be used to
- * determine whether there were referrals.
+ * 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(const unsigned int xid, struct cifs_ses *ses,
-		    struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
-		    char *ref_path)
+static int expand_dfs_referral(struct mount_ctx *mnt_ctx, const char *full_path,
+			       struct dfs_info3_param *referral)
 {
 	int rc;
-	struct dfs_info3_param referral = {0};
-	char *full_path = NULL, *mdata = NULL;
+	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;
 
-	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)
-		return -EREMOTE;
-
-	full_path = build_unc_path_to_root(ctx, cifs_sb, true);
-	if (IS_ERR(full_path))
-		return PTR_ERR(full_path);
-
-	rc = dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
-			    ref_path, &referral, NULL);
-	if (!rc) {
-		char *fake_devname = NULL;
-
-		mdata = cifs_compose_mount_options(cifs_sb->ctx->mount_options,
-						   full_path + 1, &referral,
-						   &fake_devname);
-		free_dfs_info_param(&referral);
-
-		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;
-	}
-	kfree(full_path);
-	return rc;
-}
-
-static int get_next_dfs_tgt(struct dfs_cache_tgt_list *tgt_list,
-			    struct dfs_cache_tgt_iterator **tgt_it)
-{
-	if (!*tgt_it)
-		*tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
-	else
-		*tgt_it = dfs_cache_get_next_tgt(tgt_list, *tgt_it);
-	return !*tgt_it ? -EHOSTDOWN : 0;
-}
-
-static int update_vol_info(const struct dfs_cache_tgt_iterator *tgt_it,
-			   struct smb3_fs_context *fake_ctx, struct smb3_fs_context *ctx)
-{
-	const char *tgt = dfs_cache_get_tgt_name(tgt_it);
-	int len = strlen(tgt) + 2;
-	char *new_unc;
-
-	new_unc = kmalloc(len, GFP_KERNEL);
-	if (!new_unc)
-		return -ENOMEM;
-	scnprintf(new_unc, len, "\\%s", tgt);
-
-	kfree(ctx->UNC);
-	ctx->UNC = new_unc;
-
-	if (fake_ctx->prepath) {
-		kfree(ctx->prepath);
-		ctx->prepath = fake_ctx->prepath;
-		fake_ctx->prepath = NULL;
-	}
-	memcpy(&ctx->dstaddr, &fake_ctx->dstaddr, sizeof(ctx->dstaddr));
-
-	return 0;
-}
-
-static int do_dfs_failover(const char *path, const char *full_path, struct cifs_sb_info *cifs_sb,
-			   struct smb3_fs_context *ctx, struct cifs_ses *root_ses,
-			   unsigned int *xid, struct TCP_Server_Info **server,
-			   struct cifs_ses **ses, struct cifs_tcon **tcon)
-{
-	int rc;
-	char *npath = NULL;
-	struct dfs_cache_tgt_list tgt_list = DFS_CACHE_TGT_LIST_INIT(tgt_list);
-	struct dfs_cache_tgt_iterator *tgt_it = NULL;
-	struct smb3_fs_context tmp_ctx = {NULL};
-
-	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)
-		return -EOPNOTSUPP;
-
-	npath = dfs_cache_canonical_path(path, cifs_sb->local_nls, cifs_remap(cifs_sb));
-	if (IS_ERR(npath))
-		return PTR_ERR(npath);
-
-	cifs_dbg(FYI, "%s: path=%s full_path=%s\n", __func__, npath, full_path);
-
-	rc = dfs_cache_noreq_find(npath, NULL, &tgt_list);
-	if (rc)
-		goto out;
-	/*
-	 * We use a 'tmp_ctx' here because we need pass it down to the mount_{get,put} functions to
-	 * test connection against new DFS targets.
-	 */
-	rc = smb3_fs_context_dup(&tmp_ctx, ctx);
-	if (rc)
-		goto out;
-
-	for (;;) {
-		struct dfs_info3_param ref = {0};
-		char *fake_devname = NULL, *mdata = NULL;
-
-		/* Get next DFS target server - if any */
-		rc = get_next_dfs_tgt(&tgt_list, &tgt_it);
-		if (rc)
-			break;
-
-		rc = dfs_cache_get_tgt_referral(npath, tgt_it, &ref);
-		if (rc)
-			break;
-
-		cifs_dbg(FYI, "%s: old ctx: UNC=%s prepath=%s\n", __func__, tmp_ctx.UNC,
-			 tmp_ctx.prepath);
-
-		mdata = cifs_compose_mount_options(cifs_sb->ctx->mount_options, full_path + 1, &ref,
-						   &fake_devname);
-		free_dfs_info_param(&ref);
-
-		if (IS_ERR(mdata)) {
-			rc = PTR_ERR(mdata);
-			mdata = NULL;
-		} else
-			rc = cifs_setup_volume_info(&tmp_ctx, mdata, fake_devname);
-
-		kfree(mdata);
-		kfree(fake_devname);
-
-		if (rc)
-			break;
-
-		cifs_dbg(FYI, "%s: new ctx: UNC=%s prepath=%s\n", __func__, tmp_ctx.UNC,
-			 tmp_ctx.prepath);
-
-		mount_put_conns(cifs_sb, *xid, *server, *ses, *tcon);
-		rc = mount_get_dfs_conns(&tmp_ctx, cifs_sb, xid, server, ses, tcon);
-		if (!rc || (*server && *ses)) {
-			/*
-			 * We were able to connect to new target server. Update current context with
-			 * new target server.
-			 */
-			rc = update_vol_info(tgt_it, &tmp_ctx, ctx);
-			break;
-		}
-	}
-	if (!rc) {
-		cifs_dbg(FYI, "%s: final ctx: UNC=%s prepath=%s\n", __func__, tmp_ctx.UNC,
-			 tmp_ctx.prepath);
+	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 {
 		/*
-		 * Update DFS target hint in DFS referral cache with the target server we
-		 * successfully reconnected to.
+		 * 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.
 		 */
-		rc = dfs_cache_update_tgthint(*xid, root_ses ? root_ses : *ses, cifs_sb->local_nls,
-					      cifs_remap(cifs_sb), path, tgt_it);
+		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;
 
-out:
-	kfree(npath);
-	smb3_cleanup_fs_context_contents(&tmp_ctx);
-	dfs_cache_free_tgts(&tgt_list);
 	return rc;
 }
 #endif
···
  * Check if path is remote (e.g. a DFS share). Return -EREMOTE if it is,
  * otherwise 0.
  */
-static int is_path_remote(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx,
-			  const unsigned int xid,
-			  struct TCP_Server_Info *server,
-			  struct cifs_tcon *tcon)
+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)
···
 }
 
 #ifdef CONFIG_CIFS_DFS_UPCALL
-static void set_root_ses(struct cifs_sb_info *cifs_sb, const uuid_t *mount_id, struct cifs_ses *ses,
-			 struct cifs_ses **root_ses)
+static void set_root_ses(struct mount_ctx *mnt_ctx)
 {
-	if (ses) {
+	if (mnt_ctx->ses) {
 		spin_lock(&cifs_tcp_ses_lock);
-		ses->ses_count++;
+		mnt_ctx->ses->ses_count++;
 		spin_unlock(&cifs_tcp_ses_lock);
-		dfs_cache_add_refsrv_session(mount_id, ses);
+		dfs_cache_add_refsrv_session(&mnt_ctx->mount_id, mnt_ctx->ses);
 	}
-	*root_ses = ses;
+	mnt_ctx->root_ses = mnt_ctx->ses;
 }
 
-/* Set up next dfs prefix path in @dfs_path */
-static int next_dfs_prepath(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx,
-			    const unsigned int xid, struct TCP_Server_Info *server,
-			    struct cifs_tcon *tcon, char **dfs_path)
-{
-	char *path, *npath;
-	int added_treename = is_tcon_dfs(tcon);
-	int rc;
-
-	path = cifs_build_path_to_root(ctx, cifs_sb, tcon, added_treename);
-	if (!path)
-		return -ENOMEM;
-
-	rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
-	if (rc == -EREMOTE) {
-		struct smb3_fs_context v = {NULL};
-		/* if @path contains a tree name, skip it in the prefix path */
-		if (added_treename) {
-			rc = smb3_parse_devname(path, &v);
-			if (rc)
-				goto out;
-			npath = build_unc_path_to_root(&v, cifs_sb, true);
-			smb3_cleanup_fs_context_contents(&v);
-		} else {
-			v.UNC = ctx->UNC;
-			v.prepath = path + 1;
-			npath = build_unc_path_to_root(&v, cifs_sb, true);
-		}
-
-		if (IS_ERR(npath)) {
-			rc = PTR_ERR(npath);
-			goto out;
-		}
-
-		kfree(*dfs_path);
-		*dfs_path = npath;
-		rc = -EREMOTE;
-	}
-
-out:
-	kfree(path);
-	return rc;
-}
-
-/* Check if resolved targets can handle any DFS referrals */
-static int is_referral_server(const char *ref_path, struct cifs_sb_info *cifs_sb,
-			      struct cifs_tcon *tcon, bool *ref_server)
+static int is_dfs_mount(struct mount_ctx *mnt_ctx, bool *isdfs, struct dfs_cache_tgt_list *root_tl)
 {
 	int rc;
-	struct dfs_info3_param ref = {0};
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
 
-	cifs_dbg(FYI, "%s: ref_path=%s\n", __func__, ref_path);
+	*isdfs = true;
 
-	if (is_tcon_dfs(tcon)) {
-		*ref_server = true;
-	} else {
-		char *npath;
-
-		npath = dfs_cache_canonical_path(ref_path, cifs_sb->local_nls, cifs_remap(cifs_sb));
-		if (IS_ERR(npath))
-			return PTR_ERR(npath);
-
-		rc = dfs_cache_noreq_find(npath, &ref, NULL);
-		kfree(npath);
-		if (rc) {
-			cifs_dbg(VFS, "%s: dfs_cache_noreq_find: failed (rc=%d)\n", __func__, rc);
-			return rc;
-		}
-		cifs_dbg(FYI, "%s: ref.flags=0x%x\n", __func__, ref.flags);
-		/*
-		 * Check if all targets are capable of handling DFS referrals as per
-		 * MS-DFSC 2.2.4 RESP_GET_DFS_REFERRAL.
-		 */
-		*ref_server = !!(ref.flags & DFSREF_REFERRAL_SERVER);
-		free_dfs_info_param(&ref);
-	}
-	return 0;
-}
-
-int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
-{
-	int rc = 0;
-	unsigned int xid;
-	struct TCP_Server_Info *server = NULL;
-	struct cifs_ses *ses = NULL, *root_ses = NULL;
-	struct cifs_tcon *tcon = NULL;
-	int count = 0;
-	uuid_t mount_id = {0};
-	char *ref_path = NULL, *full_path = NULL;
-	char *oldmnt = NULL;
-	bool ref_server = false;
-
-	rc = mount_get_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
+	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.
···
 	 * 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(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb), ctx->UNC + 1, NULL,
-			   NULL)) {
+	    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)
-			goto error;
+			return rc;
 		/* Check if it is fully accessible and then mount it */
-		rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
+		rc = is_path_remote(mnt_ctx);
 		if (!rc)
-			goto out;
-		if (rc != -EREMOTE)
-			goto error;
+			*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;
+
+	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);
 	}
 
-	mount_put_conns(cifs_sb, xid, server, ses, tcon);
-	/*
-	 * Ignore error check here because we may failover to other targets from cached a
-	 * referral.
-	 */
-	(void)mount_get_dfs_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
+out:
+	free_dfs_info_param(&ref);
+	return rc;
+}
 
-	/* Get path of DFS root */
-	ref_path = build_unc_path_to_root(ctx, cifs_sb, false);
-	if (IS_ERR(ref_path)) {
-		rc = PTR_ERR(ref_path);
-		ref_path = NULL;
-		goto error;
+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);
+
+	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;
 	}
 
-	uuid_gen(&mount_id);
-	set_root_ses(cifs_sb, &mount_id, ses, &root_ses);
-	do {
-		/* Save full path of last DFS path we used to resolve final target server */
-		kfree(full_path);
-		full_path = build_unc_path_to_root(ctx, cifs_sb, !!count);
-		if (IS_ERR(full_path)) {
-			rc = PTR_ERR(full_path);
-			full_path = NULL;
+	/* 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;
 		}
-		/* Chase referral */
-		oldmnt = cifs_sb->ctx->mount_options;
-		rc = expand_dfs_referral(xid, root_ses, ctx, cifs_sb, ref_path + 1);
-		if (rc)
-			break;
-		/* Connect to new DFS target only if we were redirected */
-		if (oldmnt != cifs_sb->ctx->mount_options) {
-			mount_put_conns(cifs_sb, xid, server, ses, tcon);
-			rc = mount_get_dfs_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
-		}
-		if (rc && !server && !ses) {
-			/* Failed to connect. Try to connect to other targets in the referral. */
-			rc = do_dfs_failover(ref_path + 1, full_path, cifs_sb, ctx, root_ses, &xid,
-					     &server, &ses, &tcon);
-		}
-		if (rc == -EACCES || rc == -EOPNOTSUPP || !server || !ses)
-			break;
-		if (!tcon)
-			continue;
+	}
 
-		/* Make sure that requests go through new root servers */
-		rc = is_referral_server(ref_path + 1, cifs_sb, tcon, &ref_server);
-		if (rc)
-			break;
-		if (ref_server)
-			set_root_ses(cifs_sb, &mount_id, ses, &root_ses);
-
-		/* Get next dfs path and then continue chasing them if -EREMOTE */
-		rc = next_dfs_prepath(cifs_sb, ctx, xid, server, tcon, &ref_path);
-		/* Prevent recursion on broken link referrals */
-		if (rc == -EREMOTE && ++count > MAX_NESTED_LINKS)
-			rc = -ELOOP;
-	} while (rc == -EREMOTE);
-
-	if (rc || !tcon || !ses)
-		goto error;
-
-	kfree(ref_path);
-	/*
-	 * Store DFS full path in both superblock and tree connect structures.
-	 *
-	 * For DFS root mounts, the prefix path (cifs_sb->prepath) is preserved during reconnect so
-	 * only the root path is set in cifs_sb->origin_fullpath and tcon->dfs_path. And for DFS
-	 * links, the prefix path is included in both and may be changed during reconnect.  See
-	 * cifs_tree_connect().
-	 */
-	ref_path = dfs_cache_canonical_path(full_path, cifs_sb->local_nls, cifs_remap(cifs_sb));
+out:
 	kfree(full_path);
-	full_path = NULL;
+	return rc;
+}
 
-	if (IS_ERR(ref_path)) {
-		rc = PTR_ERR(ref_path);
-		ref_path = NULL;
-		goto error;
+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;
 	}
-	cifs_sb->origin_fullpath = ref_path;
 
-	ref_path = kstrdup(cifs_sb->origin_fullpath, GFP_KERNEL);
-	if (!ref_path) {
-		rc = -ENOMEM;
-		goto error;
+	/* 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 */
+	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);
+			break;
+		}
 	}
-	spin_lock(&cifs_tcp_ses_lock);
-	tcon->dfs_path = ref_path;
-	ref_path = NULL;
-	spin_unlock(&cifs_tcp_ses_lock);
 
+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;
+
+	server->origin_fullpath = mnt_ctx->origin_fullpath;
+	server->leaf_fullpath = mnt_ctx->leaf_fullpath;
+	server->current_fullpath = mnt_ctx->leaf_fullpath;
+	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;
+
+	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 == -EREMOTE)
+		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).
+	 * 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.
+	 * 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, &mount_id);
+	uuid_copy(&cifs_sb->dfs_mount_id, &mnt_ctx.mount_id);
 
 out:
-	free_xid(xid);
-	cifs_try_adding_channels(cifs_sb, ses);
-	return mount_setup_tlink(cifs_sb, ses, tcon);
+	free_xid(mnt_ctx.xid);
+	cifs_try_adding_channels(cifs_sb, mnt_ctx.ses);
+	return mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
 
 error:
-	kfree(ref_path);
-	kfree(full_path);
-	kfree(cifs_sb->origin_fullpath);
-	dfs_cache_put_refsrv_sessions(&mount_id);
-	mount_put_conns(cifs_sb, xid, server, ses, tcon);
+	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;
-	unsigned int xid;
-	struct cifs_ses *ses;
-	struct cifs_tcon *tcon;
-	struct TCP_Server_Info *server;
+	struct mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
 
-	rc = mount_get_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
+	rc = mount_get_conns(&mnt_ctx);
 	if (rc)
 		goto error;
 
-	if (tcon) {
-		rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
+	if (mnt_ctx.tcon) {
+		rc = is_path_remote(&mnt_ctx);
 		if (rc == -EREMOTE)
 			rc = -EOPNOTSUPP;
 		if (rc)
 			goto error;
 	}
 
-	free_xid(xid);
-
-	return mount_setup_tlink(cifs_sb, ses, tcon);
+	free_xid(mnt_ctx.xid);
+	return mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
 
 error:
-	mount_put_conns(cifs_sb, xid, server, ses, tcon);
+	mount_put_conns(&mnt_ctx);
 	return rc;
 }
 #endif
···
 	kfree(cifs_sb->prepath);
 #ifdef CONFIG_CIFS_DFS_UPCALL
 	dfs_cache_put_refsrv_sessions(&cifs_sb->dfs_mount_id);
-	kfree(cifs_sb->origin_fullpath);
 #endif
 	call_rcu(&cifs_sb->rcu, delayed_free);
 }
···
 }
 
 #ifdef CONFIG_CIFS_DFS_UPCALL
+static void mark_tcon_tcp_ses_for_reconnect(struct cifs_tcon *tcon)
+{
+	int i;
+
+	for (i = 0; i < tcon->ses->chan_count; i++) {
+		spin_lock(&GlobalMid_Lock);
+		if (tcon->ses->chans[i].server->tcpStatus != CifsExiting)
+			tcon->ses->chans[i].server->tcpStatus = CifsNeedReconnect;
+		spin_unlock(&GlobalMid_Lock);
+	}
+}
+
+/* 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;
+		mark_tcon_tcp_ses_for_reconnect(tcon);
+	}
+
+	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 dfs_cache_tgt_list tl;
-	struct dfs_cache_tgt_iterator *it = NULL;
+	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;
-	const char *tcp_host;
-	size_t tcp_host_len;
-	const char *dfs_host;
-	size_t dfs_host_len;
-	char *share = NULL, *prefix = NULL;
 	struct dfs_info3_param ref = {0};
-	bool isroot;
 
 	tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
 	if (!tree)
 		return -ENOMEM;
 
-	/* If it is not dfs or there was no cached dfs referral, then reconnect to same share */
-	if (!tcon->dfs_path || dfs_cache_noreq_find(tcon->dfs_path + 1, &ref, &tl)) {
-		if (tcon->ipc) {
-			scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
-			rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
-		} else {
-			rc = ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, nlsc);
-		}
+	if (tcon->ipc) {
+		scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
+		rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
 		goto out;
 	}
 
-	isroot = ref.server_type == DFS_TYPE_ROOT;
+	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->treeName, 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);
 
-	extract_unc_hostname(server->hostname, &tcp_host, &tcp_host_len);
-
-	for (it = dfs_cache_get_tgt_iterator(&tl); it; it = dfs_cache_get_next_tgt(&tl, it)) {
-		bool target_match;
-
-		kfree(share);
-		kfree(prefix);
-		share = NULL;
-		prefix = NULL;
-
-		rc = dfs_cache_get_tgt_share(tcon->dfs_path + 1, it, &share, &prefix);
-		if (rc) {
-			cifs_dbg(VFS, "%s: failed to parse target share %d\n",
-				 __func__, rc);
-			continue;
-		}
-
-		extract_unc_hostname(share, &dfs_host, &dfs_host_len);
-
-		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);
-				break;
-			}
-
-			if (!target_match) {
-				cifs_dbg(FYI, "%s: skipping target\n", __func__);
-				continue;
-			}
-		}
-
-		if (tcon->ipc) {
-			scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", share);
-			rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
-		} else {
-			scnprintf(tree, MAX_TREE_SIZE, "\\%s", share);
-			rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
-			/* Only handle prefix paths of DFS link targets */
-			if (!rc && !isroot) {
-				rc = update_super_prepath(tcon, prefix);
-				break;
-			}
-		}
-		if (rc == -EREMOTE)
-			break;
-	}
-
-	kfree(share);
-	kfree(prefix);
-
-	if (!rc) {
-		if (it)
-			rc = dfs_cache_noreq_update_tgthint(tcon->dfs_path + 1, it);
-		else
-			rc = -ENOENT;
-	}
-	dfs_cache_free_tgts(&tl);
 out:
 	kfree(tree);
+	cifs_put_tcp_super(sb);
+
 	return rc;
 }
 #else

fs/cifs/dfs_cache.c

···
 			seq_printf(m,
 				   "cache entry: path=%s,type=%s,ttl=%d,etime=%ld,hdr_flags=0x%x,ref_flags=0x%x,interlink=%s,path_consumed=%d,expired=%s\n",
 				   ce->path, ce->srvtype == DFS_TYPE_ROOT ? "root" : "link",
-				   ce->ttl, ce->etime.tv_nsec, ce->ref_flags, ce->hdr_flags,
+				   ce->ttl, ce->etime.tv_nsec, ce->hdr_flags, ce->ref_flags,
 				   IS_DFS_INTERLINK(ce->hdr_flags) ? "yes" : "no",
 				   ce->path_consumed, cache_entry_expired(ce) ? "yes" : "no");
 
···
 }
 
 /* Refresh dfs referral of tcon and mark it for reconnect if needed */
-static int refresh_tcon(struct cifs_ses **sessions, struct cifs_tcon *tcon, bool force_refresh)
+static int __refresh_tcon(const char *path, struct cifs_ses **sessions, struct cifs_tcon *tcon,
+			  bool force_refresh)
 {
-	const char *path = tcon->dfs_path + 1;
 	struct cifs_ses *ses;
 	struct cache_entry *ce;
 	struct dfs_info3_param *refs = NULL;
···
 	return rc;
 }
 
+static int refresh_tcon(struct cifs_ses **sessions, struct cifs_tcon *tcon, bool force_refresh)
+{
+	struct TCP_Server_Info *server = tcon->ses->server;
+
+	mutex_lock(&server->refpath_lock);
+	if (strcasecmp(server->leaf_fullpath, server->origin_fullpath))
+		__refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, force_refresh);
+	mutex_unlock(&server->refpath_lock);
+
+	__refresh_tcon(server->origin_fullpath + 1, sessions, tcon, force_refresh);
+
+	return 0;
+}
+
 /**
  * dfs_cache_remount_fs - remount a DFS share
  *
···
 int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb)
 {
 	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
 	struct mount_group *mg;
 	struct cifs_ses *sessions[CACHE_MAX_ENTRIES + 1] = {NULL};
 	int rc;
···
 		return -EINVAL;
 
 	tcon = cifs_sb_master_tcon(cifs_sb);
-	if (!tcon->dfs_path) {
-		cifs_dbg(FYI, "%s: not a dfs tcon\n", __func__);
+	server = tcon->ses->server;
+
+	if (!server->origin_fullpath) {
+		cifs_dbg(FYI, "%s: not a dfs mount\n", __func__);
 		return 0;
 	}
 
 	if (uuid_is_null(&cifs_sb->dfs_mount_id)) {
-		cifs_dbg(FYI, "%s: tcon has no dfs mount group id\n", __func__);
+		cifs_dbg(FYI, "%s: no dfs mount group id\n", __func__);
 		return -EINVAL;
 	}
 
···
 	mg = find_mount_group_locked(&cifs_sb->dfs_mount_id);
 	if (IS_ERR(mg)) {
 		mutex_unlock(&mount_group_list_lock);
-		cifs_dbg(FYI, "%s: tcon has ipc session to refresh referral\n", __func__);
+		cifs_dbg(FYI, "%s: no ipc session for refreshing referral\n", __func__);
 		return PTR_ERR(mg);
 	}
 	kref_get(&mg->refcount);
···
 
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
+		if (!server->is_dfs_conn)
+			continue;
+
 		list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
 			list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
-				if (tcon->dfs_path) {
+				if (!tcon->ipc && !tcon->need_reconnect) {
 					tcon->tc_count++;
 					list_add_tail(&tcon->ulist, &tcons);
 				}
···
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	list_for_each_entry_safe(tcon, ntcon, &tcons, ulist) {
+		struct TCP_Server_Info *server = tcon->ses->server;
+
 		list_del_init(&tcon->ulist);
-		refresh_tcon(sessions, tcon, false);
+
+		mutex_lock(&server->refpath_lock);
+		if (strcasecmp(server->leaf_fullpath, server->origin_fullpath))
+			__refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, false);
+		mutex_unlock(&server->refpath_lock);
+
+		__refresh_tcon(server->origin_fullpath + 1, sessions, tcon, false);
 		cifs_put_tcon(tcon);
 	}
 }

fs/cifs/file.c

···
 	tcon = tlink_tcon(smbfile->tlink);
 	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC)) {
 		server = tcon->ses->server;
-		if (server->ops->flush)
-			rc = server->ops->flush(xid, tcon, &smbfile->fid);
-		else
+		if (server->ops->flush == NULL) {
 			rc = -ENOSYS;
+			goto strict_fsync_exit;
+		}
+
+		if ((OPEN_FMODE(smbfile->f_flags) & FMODE_WRITE) == 0) {
+			smbfile = find_writable_file(CIFS_I(inode), FIND_WR_ANY);
+			if (smbfile) {
+				rc = server->ops->flush(xid, tcon, &smbfile->fid);
+				cifsFileInfo_put(smbfile);
+			} else
+				cifs_dbg(FYI, "ignore fsync for file not open for write\n");
+		} else
+			rc = server->ops->flush(xid, tcon, &smbfile->fid);
 	}
 
+strict_fsync_exit:
 	free_xid(xid);
 	return rc;
 }
···
 	struct cifs_tcon *tcon;
 	struct TCP_Server_Info *server;
 	struct cifsFileInfo *smbfile = file->private_data;
+	struct inode *inode = file_inode(file);
 	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 
 	rc = file_write_and_wait_range(file, start, end);
···
 	tcon = tlink_tcon(smbfile->tlink);
 	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC)) {
 		server = tcon->ses->server;
-		if (server->ops->flush)
-			rc = server->ops->flush(xid, tcon, &smbfile->fid);
-		else
+		if (server->ops->flush == NULL) {
 			rc = -ENOSYS;
+			goto fsync_exit;
+		}
+
+		if ((OPEN_FMODE(smbfile->f_flags) & FMODE_WRITE) == 0) {
+			smbfile = find_writable_file(CIFS_I(inode), FIND_WR_ANY);
+			if (smbfile) {
+				rc = server->ops->flush(xid, tcon, &smbfile->fid);
+				cifsFileInfo_put(smbfile);
+			} else
+				cifs_dbg(FYI, "ignore fsync for file not open for write\n");
+		} else
+			rc = server->ops->flush(xid, tcon, &smbfile->fid);
 	}
 
+fsync_exit:
 	free_xid(xid);
 	return rc;
 }

fs/cifs/fs_context.c

···
 	new_ctx->nodename = NULL;
 	new_ctx->username = NULL;
 	new_ctx->password = NULL;
+	new_ctx->server_hostname = NULL;
 	new_ctx->domainname = NULL;
+	new_ctx->workstation_name = NULL;
 	new_ctx->UNC = NULL;
 	new_ctx->source = NULL;
 	new_ctx->iocharset = NULL;
···
 	DUP_CTX_STR(UNC);
 	DUP_CTX_STR(source);
 	DUP_CTX_STR(domainname);
+	DUP_CTX_STR(workstation_name);
 	DUP_CTX_STR(nodename);
 	DUP_CTX_STR(iocharset);
 
···
 		return -EINVAL;
 
 	/* record the server hostname */
+	kfree(ctx->server_hostname);
 	ctx->server_hostname = kstrndup(devname + 2, pos - devname - 2, GFP_KERNEL);
 	if (!ctx->server_hostname)
 		return -ENOMEM;
···
 		cifs_errorf(fc, "can not change domainname during remount\n");
 		return -EINVAL;
 	}
+	if (new_ctx->workstation_name &&
+	    (!old_ctx->workstation_name || strcmp(new_ctx->workstation_name, old_ctx->workstation_name))) {
+		cifs_errorf(fc, "can not change workstation_name during remount\n");
+		return -EINVAL;
+	}
 	if (new_ctx->nodename &&
 	    (!old_ctx->nodename || strcmp(new_ctx->nodename, old_ctx->nodename))) {
 		cifs_errorf(fc, "can not change nodename during remount\n");
···
 		return rc;
 
 	/*
-	 * We can not change UNC/username/password/domainname/nodename/iocharset
+	 * We can not change UNC/username/password/domainname/
+	 * workstation_name/nodename/iocharset
 	 * during reconnect so ignore what we have in the new context and
 	 * just use what we already have in cifs_sb->ctx.
 	 */
···
 	STEAL_STRING(cifs_sb, ctx, username);
 	STEAL_STRING(cifs_sb, ctx, password);
 	STEAL_STRING(cifs_sb, ctx, domainname);
+	STEAL_STRING(cifs_sb, ctx, workstation_name);
 	STEAL_STRING(cifs_sb, ctx, nodename);
 	STEAL_STRING(cifs_sb, ctx, iocharset);
 
···
 
 int smb3_init_fs_context(struct fs_context *fc)
 {
+	int rc;
 	struct smb3_fs_context *ctx;
 	char *nodename = utsname()->nodename;
 	int i;
 
 	ctx = kzalloc(sizeof(struct smb3_fs_context), GFP_KERNEL);
-	if (unlikely(!ctx))
-		return -ENOMEM;
+	if (unlikely(!ctx)) {
+		rc = -ENOMEM;
+		goto err_exit;
+	}
+
+	ctx->workstation_name = kstrdup(nodename, GFP_KERNEL);
+	if (unlikely(!ctx->workstation_name)) {
+		rc = -ENOMEM;
+		goto err_exit;
+	}
 
 	/*
 	 * does not have to be perfect mapping since field is
···
 	fc->fs_private = ctx;
 	fc->ops = &smb3_fs_context_ops;
 	return 0;
+
+err_exit:
+	if (ctx) {
+		kfree(ctx->workstation_name);
+		kfree(ctx);
+	}
+
+	return rc;
 }
 
 void
···
 	ctx->source = NULL;
 	kfree(ctx->domainname);
 	ctx->domainname = NULL;
+	kfree(ctx->workstation_name);
+	ctx->workstation_name = NULL;
 	kfree(ctx->nodename);
 	ctx->nodename = NULL;
 	kfree(ctx->iocharset);

fs/cifs/fs_context.h

···
 	char *server_hostname;
 	char *UNC;
 	char *nodename;
+	char *workstation_name;
 	char *iocharset;  /* local code page for mapping to and from Unicode */
 	char source_rfc1001_name[RFC1001_NAME_LEN_WITH_NULL]; /* clnt nb name */
 	char target_rfc1001_name[RFC1001_NAME_LEN_WITH_NULL]; /* srvr nb name */

fs/cifs/fscache.c

···
 	char *sharename;
 	struct cifs_fscache_super_auxdata auxdata;
 
+	/*
+	 * Check if cookie was already initialized so don't reinitialize it.
+	 * In the future, as we integrate with newer fscache features,
+	 * we may want to instead add a check if cookie has changed
+	 */
+	if (tcon->fscache == NULL)
+		return;
+
 	sharename = extract_sharename(tcon->treeName);
 	if (IS_ERR(sharename)) {
 		cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);

fs/cifs/misc.c

···
 		INIT_LIST_HEAD(&ret_buf->tcon_list);
 		mutex_init(&ret_buf->session_mutex);
 		spin_lock_init(&ret_buf->iface_lock);
+		spin_lock_init(&ret_buf->chan_lock);
 	}
 	return ret_buf;
 }
···
 	kfree_sensitive(buf_to_free->password);
 	kfree(buf_to_free->user_name);
 	kfree(buf_to_free->domainName);
+	kfree(buf_to_free->workstation_name);
 	kfree_sensitive(buf_to_free->auth_key.response);
 	kfree(buf_to_free->iface_list);
 	kfree_sensitive(buf_to_free);
···
 	kfree(buf_to_free->nativeFileSystem);
 	kfree_sensitive(buf_to_free->password);
 	kfree(buf_to_free->crfid.fid);
-#ifdef CONFIG_CIFS_DFS_UPCALL
-	kfree(buf_to_free->dfs_path);
-#endif
 	kfree(buf_to_free);
 }
 
···
 	return rc;
 }
 
-static void tcon_super_cb(struct super_block *sb, void *arg)
+int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
 {
-	struct super_cb_data *sd = arg;
-	struct cifs_tcon *tcon = sd->data;
-	struct cifs_sb_info *cifs_sb;
-
-	if (sd->sb)
-		return;
-
-	cifs_sb = CIFS_SB(sb);
-	if (tcon->dfs_path && cifs_sb->origin_fullpath &&
-	    !strcasecmp(tcon->dfs_path, cifs_sb->origin_fullpath))
-		sd->sb = sb;
-}
-
-static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
-{
-	return __cifs_get_super(tcon_super_cb, tcon);
-}
-
-static inline void cifs_put_tcon_super(struct super_block *sb)
-{
-	__cifs_put_super(sb);
-}
-#else
-static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
-{
-	return ERR_PTR(-EOPNOTSUPP);
-}
-
-static inline void cifs_put_tcon_super(struct super_block *sb)
-{
-}
-#endif
-
-int update_super_prepath(struct cifs_tcon *tcon, char *prefix)
-{
-	struct super_block *sb;
-	struct cifs_sb_info *cifs_sb;
-	int rc = 0;
-
-	sb = cifs_get_tcon_super(tcon);
-	if (IS_ERR(sb))
-		return PTR_ERR(sb);
-
-	cifs_sb = CIFS_SB(sb);
-
 	kfree(cifs_sb->prepath);
 
 	if (prefix && *prefix) {
 		cifs_sb->prepath = kstrdup(prefix, GFP_ATOMIC);
-		if (!cifs_sb->prepath) {
-			rc = -ENOMEM;
-			goto out;
-		}
+		if (!cifs_sb->prepath)
+			return -ENOMEM;
 
 		convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
 	} else
 		cifs_sb->prepath = NULL;
 
 	cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
-
-out:
-	cifs_put_tcon_super(sb);
-	return rc;
+	return 0;
 }
+#endif

fs/cifs/ntlmssp.h

···
  */
 
 int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len, struct cifs_ses *ses);
-void build_ntlmssp_negotiate_blob(unsigned char *pbuffer, struct cifs_ses *ses);
+int build_ntlmssp_negotiate_blob(unsigned char **pbuffer, u16 *buflen,
+				 struct cifs_ses *ses,
+				 const struct nls_table *nls_cp);
 int build_ntlmssp_auth_blob(unsigned char **pbuffer, u16 *buflen,
 			struct cifs_ses *ses,
 			const struct nls_table *nls_cp);

fs/cifs/sess.c

···
 {
 	int i;
 
+	spin_lock(&ses->chan_lock);
 	for (i = 0; i < ses->chan_count; i++) {
-		if (is_server_using_iface(ses->chans[i].server, iface))
+		if (is_server_using_iface(ses->chans[i].server, iface)) {
+			spin_unlock(&ses->chan_lock);
 			return true;
+		}
 	}
+	spin_unlock(&ses->chan_lock);
 	return false;
 }
 
 /* returns number of channels added */
 int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
 {
-	int old_chan_count = ses->chan_count;
-	int left = ses->chan_max - ses->chan_count;
+	int old_chan_count, new_chan_count;
+	int left;
 	int i = 0;
 	int rc = 0;
 	int tries = 0;
 	struct cifs_server_iface *ifaces = NULL;
 	size_t iface_count;
 
+	if (ses->server->dialect < SMB30_PROT_ID) {
+		cifs_dbg(VFS, "multichannel is not supported on this protocol version, use 3.0 or above\n");
+		return 0;
+	}
+
+	spin_lock(&ses->chan_lock);
+
+	new_chan_count = old_chan_count = ses->chan_count;
+	left = ses->chan_max - ses->chan_count;
+
 	if (left <= 0) {
 		cifs_dbg(FYI,
 			 "ses already at max_channels (%zu), nothing to open\n",
 			 ses->chan_max);
-		return 0;
-	}
-
-	if (ses->server->dialect < SMB30_PROT_ID) {
-		cifs_dbg(VFS, "multichannel is not supported on this protocol version, use 3.0 or above\n");
+		spin_unlock(&ses->chan_lock);
 		return 0;
 	}
 
 	if (!(ses->server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) {
 		cifs_dbg(VFS, "server %s does not support multichannel\n", ses->server->hostname);
 		ses->chan_max = 1;
+		spin_unlock(&ses->chan_lock);
 		return 0;
 	}
+	spin_unlock(&ses->chan_lock);
 
 	/*
 	 * Make a copy of the iface list at the time and use that
···
 		cifs_dbg(FYI, "successfully opened new channel on iface#%d\n",
 			 i);
 		left--;
+		new_chan_count++;
 	}
 
 	kfree(ifaces);
-	return ses->chan_count - old_chan_count;
+	return new_chan_count - old_chan_count;
 }
 
 /*
···
 {
 	int i;
 
+	spin_lock(&ses->chan_lock);
 	for (i = 0; i < ses->chan_count; i++) {
-		if (ses->chans[i].server == server)
+		if (ses->chans[i].server == server) {
+			spin_unlock(&ses->chan_lock);
 			return &ses->chans[i];
+		}
 	}
+	spin_unlock(&ses->chan_lock);
 	return NULL;
 }
 
···
 cifs_ses_add_channel(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
 		     struct cifs_server_iface *iface)
 {
+	struct TCP_Server_Info *chan_server;
 	struct cifs_chan *chan;
 	struct smb3_fs_context ctx = {NULL};
 	static const char unc_fmt[] = "\\%s\\foo";
···
 	       SMB2_CLIENT_GUID_SIZE);
 	ctx.use_client_guid = true;
 
-	mutex_lock(&ses->session_mutex);
+	chan_server = cifs_get_tcp_session(&ctx, ses->server);
 
+	mutex_lock(&ses->session_mutex);
+	spin_lock(&ses->chan_lock);
 	chan = ses->binding_chan = &ses->chans[ses->chan_count];
-	chan->server = cifs_get_tcp_session(&ctx);
+	chan->server = chan_server;
 	if (IS_ERR(chan->server)) {
 		rc = PTR_ERR(chan->server);
 		chan->server = NULL;
+		spin_unlock(&ses->chan_lock);
 		goto out;
 	}
-	spin_lock(&cifs_tcp_ses_lock);
-	chan->server->is_channel = true;
-	spin_unlock(&cifs_tcp_ses_lock);
+	spin_unlock(&ses->chan_lock);
 
 	/*
 	 * We need to allocate the server crypto now as we will need
···
 	 * ses to the new server.
 	 */
 
+	spin_lock(&ses->chan_lock);
 	ses->chan_count++;
 	atomic_set(&ses->chan_seq, 0);
+	spin_unlock(&ses->chan_lock);
+
 out:
 	ses->binding = false;
 	ses->binding_chan = NULL;
···
 	return 0;
 }
 
+static int size_of_ntlmssp_blob(struct cifs_ses *ses, int base_size)
+{
+	int sz = base_size + ses->auth_key.len
+		- CIFS_SESS_KEY_SIZE + CIFS_CPHTXT_SIZE + 2;
+
+	if (ses->domainName)
+		sz += sizeof(__le16) * strnlen(ses->domainName, CIFS_MAX_DOMAINNAME_LEN);
+	else
+		sz += sizeof(__le16);
+
+	if (ses->user_name)
+		sz += sizeof(__le16) * strnlen(ses->user_name, CIFS_MAX_USERNAME_LEN);
+	else
+		sz += sizeof(__le16);
+
+	sz += sizeof(__le16) * strnlen(ses->workstation_name, CIFS_MAX_WORKSTATION_LEN);
+
+	return sz;
+}
+
+static inline void cifs_security_buffer_from_str(SECURITY_BUFFER *pbuf,
+						 char *str_value,
+						 int str_length,
+						 unsigned char *pstart,
+						 unsigned char **pcur,
+						 const struct nls_table *nls_cp)
+{
+	unsigned char *tmp = pstart;
+	int len;
+
+	if (!pbuf)
+		return;
+
+	if (!pcur)
+		pcur = &tmp;
+
+	if (!str_value) {
+		pbuf->BufferOffset = cpu_to_le32(*pcur - pstart);
+		pbuf->Length = 0;
+		pbuf->MaximumLength = 0;
+		*pcur += sizeof(__le16);
+	} else {
+		len = cifs_strtoUTF16((__le16 *)*pcur,
+				      str_value,
+				      str_length,
+				      nls_cp);
+		len *= sizeof(__le16);
+		pbuf->BufferOffset = cpu_to_le32(*pcur - pstart);
+		pbuf->Length = cpu_to_le16(len);
+		pbuf->MaximumLength = cpu_to_le16(len);
+		*pcur += len;
+	}
+}
+
 /* BB Move to ntlmssp.c eventually */
 
-/* We do not malloc the blob, it is passed in pbuffer, because
-   it is fixed size, and small, making this approach cleaner */
-void build_ntlmssp_negotiate_blob(unsigned char *pbuffer,
-					 struct cifs_ses *ses)
+int build_ntlmssp_negotiate_blob(unsigned char **pbuffer,
+				 u16 *buflen,
+				 struct cifs_ses *ses,
+				 const struct nls_table *nls_cp)
 {
+	int rc = 0;
 	struct TCP_Server_Info *server = cifs_ses_server(ses);
-	NEGOTIATE_MESSAGE *sec_blob = (NEGOTIATE_MESSAGE *)pbuffer;
+	NEGOTIATE_MESSAGE *sec_blob;
 	__u32 flags;
+	unsigned char *tmp;
+	int len;
 
-	memset(pbuffer, 0, sizeof(NEGOTIATE_MESSAGE));
+	len = size_of_ntlmssp_blob(ses, sizeof(NEGOTIATE_MESSAGE));
+	*pbuffer = kmalloc(len, GFP_KERNEL);
+	if (!*pbuffer) {
+		rc = -ENOMEM;
+		cifs_dbg(VFS, "Error %d during NTLMSSP allocation\n", rc);
+		*buflen = 0;
+		goto setup_ntlm_neg_ret;
+	}
+	sec_blob = (NEGOTIATE_MESSAGE *)*pbuffer;
+
+	memset(*pbuffer, 0, sizeof(NEGOTIATE_MESSAGE));
 	memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
 	sec_blob->MessageType = NtLmNegotiate;
 
···
 	if (!server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
 		flags |= NTLMSSP_NEGOTIATE_KEY_XCH;
 
+	tmp = *pbuffer + sizeof(NEGOTIATE_MESSAGE);
 	sec_blob->NegotiateFlags = cpu_to_le32(flags);
 
-	sec_blob->WorkstationName.BufferOffset = 0;
-	sec_blob->WorkstationName.Length = 0;
-	sec_blob->WorkstationName.MaximumLength = 0;
+	/* these fields should be null in negotiate phase MS-NLMP 3.1.5.1.1 */
+	cifs_security_buffer_from_str(&sec_blob->DomainName,
+				      NULL,
+				      CIFS_MAX_DOMAINNAME_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
 
-	/* Domain name is sent on the Challenge not Negotiate NTLMSSP request */
-	sec_blob->DomainName.BufferOffset = 0;
-	sec_blob->DomainName.Length = 0;
-	sec_blob->DomainName.MaximumLength = 0;
-}
+	cifs_security_buffer_from_str(&sec_blob->WorkstationName,
+				      NULL,
+				      CIFS_MAX_WORKSTATION_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
 
-static int size_of_ntlmssp_blob(struct cifs_ses *ses)
-{
-	int sz = sizeof(AUTHENTICATE_MESSAGE) + ses->auth_key.len
-		- CIFS_SESS_KEY_SIZE + CIFS_CPHTXT_SIZE + 2;
-
-	if (ses->domainName)
-		sz += 2 * strnlen(ses->domainName, CIFS_MAX_DOMAINNAME_LEN);
-	else
-		sz += 2;
-
-	if (ses->user_name)
-		sz += 2 * strnlen(ses->user_name, CIFS_MAX_USERNAME_LEN);
-	else
-		sz += 2;
-
-	return sz;
+	*buflen = tmp - *pbuffer;
+setup_ntlm_neg_ret:
+	return rc;
 }
 
 int build_ntlmssp_auth_blob(unsigned char **pbuffer,
···
 	AUTHENTICATE_MESSAGE *sec_blob;
 	__u32 flags;
 	unsigned char *tmp;
+	int len;
 
 	rc = setup_ntlmv2_rsp(ses, nls_cp);
 	if (rc) {
···
 		*buflen = 0;
 		goto setup_ntlmv2_ret;
 	}
-	*pbuffer = kmalloc(size_of_ntlmssp_blob(ses), GFP_KERNEL);
+
+	len = size_of_ntlmssp_blob(ses, sizeof(AUTHENTICATE_MESSAGE));
+	*pbuffer = kmalloc(len, GFP_KERNEL);
 	if (!*pbuffer) {
 		rc = -ENOMEM;
 		cifs_dbg(VFS, "Error %d during NTLMSSP allocation\n", rc);
···
 		NTLMSSP_REQUEST_TARGET | NTLMSSP_NEGOTIATE_TARGET_INFO |
 		NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
 		NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC |
-		NTLMSSP_NEGOTIATE_SEAL;
+		NTLMSSP_NEGOTIATE_SEAL | NTLMSSP_NEGOTIATE_WORKSTATION_SUPPLIED;
 	if (ses->server->sign)
 		flags |= NTLMSSP_NEGOTIATE_SIGN;
 	if (!ses->server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
···
 		sec_blob->NtChallengeResponse.MaximumLength = 0;
 	}
 
-	if (ses->domainName == NULL) {
-		sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-		sec_blob->DomainName.Length = 0;
-		sec_blob->DomainName.MaximumLength = 0;
-		tmp += 2;
-	} else {
-		int len;
-		len = cifs_strtoUTF16((__le16 *)tmp, ses->domainName,
-				      CIFS_MAX_DOMAINNAME_LEN, nls_cp);
-		len *= 2; /* unicode is 2 bytes each */
-		sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-		sec_blob->DomainName.Length = cpu_to_le16(len);
-		sec_blob->DomainName.MaximumLength = cpu_to_le16(len);
-		tmp += len;
-	}
+	cifs_security_buffer_from_str(&sec_blob->DomainName,
+				      ses->domainName,
+				      CIFS_MAX_DOMAINNAME_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
 
-	if (ses->user_name == NULL) {
-		sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-		sec_blob->UserName.Length = 0;
-		sec_blob->UserName.MaximumLength = 0;
-		tmp += 2;
-	} else {
-		int len;
-		len = cifs_strtoUTF16((__le16 *)tmp, ses->user_name,
-				      CIFS_MAX_USERNAME_LEN, nls_cp);
-		len *= 2; /* unicode is 2 bytes each */
-		sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-		sec_blob->UserName.Length = cpu_to_le16(len);
-		sec_blob->UserName.MaximumLength = cpu_to_le16(len);
-		tmp += len;
-	}
+	cifs_security_buffer_from_str(&sec_blob->UserName,
+				      ses->user_name,
+				      CIFS_MAX_USERNAME_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
 
-	sec_blob->WorkstationName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-	sec_blob->WorkstationName.Length = 0;
-	sec_blob->WorkstationName.MaximumLength = 0;
-	tmp += 2;
+	cifs_security_buffer_from_str(&sec_blob->WorkstationName,
+				      ses->workstation_name,
+				      CIFS_MAX_WORKSTATION_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
 
 	if (((ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_KEY_XCH) ||
 		(ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_EXTENDED_SEC))
···
 	struct cifs_ses *ses = sess_data->ses;
 	__u16 bytes_remaining;
 	char *bcc_ptr;
+	unsigned char *ntlmsspblob = NULL;
 	u16 blob_len;
 
 	cifs_dbg(FYI, "rawntlmssp session setup negotiate phase\n");
···
 	pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
 
 	/* Build security blob before we assemble the request */
-	build_ntlmssp_negotiate_blob(pSMB->req.SecurityBlob, ses);
-	sess_data->iov[1].iov_len = sizeof(NEGOTIATE_MESSAGE);
-	sess_data->iov[1].iov_base = pSMB->req.SecurityBlob;
-	pSMB->req.SecurityBlobLength = cpu_to_le16(sizeof(NEGOTIATE_MESSAGE));
+	rc = build_ntlmssp_negotiate_blob(&ntlmsspblob,
+				     &blob_len, ses,
+				     sess_data->nls_cp);
+	if (rc)
+		goto out;
+
+	sess_data->iov[1].iov_len = blob_len;
+	sess_data->iov[1].iov_base = ntlmsspblob;
+	pSMB->req.SecurityBlobLength = cpu_to_le16(blob_len);
 
 	rc = _sess_auth_rawntlmssp_assemble_req(sess_data);
 	if (rc)

fs/cifs/smb2inode.c

···
 	struct smb2_file_link_info link_info;
 };
 
+/*
+ * note: If cfile is passed, the reference to it is dropped here.
+ * So make sure that you do not reuse cfile after return from this func.
+ */
 static int
 smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		 struct cifs_sb_info *cifs_sb, const char *full_path,
···
 		create_options |= OPEN_REPARSE_POINT;
 
 		/* Failed on a symbolic link - query a reparse point info */
+		cifs_get_readable_path(tcon, full_path, &cfile);
 		rc = smb2_compound_op(xid, tcon, cifs_sb, full_path,
 				      FILE_READ_ATTRIBUTES, FILE_OPEN,
 				      create_options, ACL_NO_MODE,
-				      smb2_data, SMB2_OP_QUERY_INFO, NULL);
+				      smb2_data, SMB2_OP_QUERY_INFO, cfile);
 	}
 	if (rc)
 		goto out;
···
 		create_options |= OPEN_REPARSE_POINT;
 
 		/* Failed on a symbolic link - query a reparse point info */
+		cifs_get_readable_path(tcon, full_path, &cfile);
 		rc = smb2_compound_op(xid, tcon, cifs_sb, full_path,
 				      FILE_READ_ATTRIBUTES, FILE_OPEN,
 				      create_options, ACL_NO_MODE,
-				      smb2_data, SMB2_OP_POSIX_QUERY_INFO, NULL);
+				      smb2_data, SMB2_OP_POSIX_QUERY_INFO, cfile);
 	}
 	if (rc)
 		goto out;
···
 		   struct cifs_sb_info *cifs_sb, bool set_alloc)
 {
 	__le64 eof = cpu_to_le64(size);
+	struct cifsFileInfo *cfile;
 
+	cifs_get_writable_path(tcon, full_path, FIND_WR_ANY, &cfile);
 	return smb2_compound_op(xid, tcon, cifs_sb, full_path,
 				FILE_WRITE_DATA, FILE_OPEN, 0, ACL_NO_MODE,
-				&eof, SMB2_OP_SET_EOF, NULL);
+				&eof, SMB2_OP_SET_EOF, cfile);
 }
 
 int
···
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 	struct tcon_link *tlink;
+	struct cifs_tcon *tcon;
+	struct cifsFileInfo *cfile;
 	int rc;
 
 	if ((buf->CreationTime == 0) && (buf->LastAccessTime == 0) &&
···
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
+	tcon = tlink_tcon(tlink);
 
-	rc = smb2_compound_op(xid, tlink_tcon(tlink), cifs_sb, full_path,
+	cifs_get_writable_path(tcon, full_path, FIND_WR_ANY, &cfile);
+	rc = smb2_compound_op(xid, tcon, cifs_sb, full_path,
 			      FILE_WRITE_ATTRIBUTES, FILE_OPEN,
-			      0, ACL_NO_MODE, buf, SMB2_OP_SET_INFO, NULL);
+			      0, ACL_NO_MODE, buf, SMB2_OP_SET_INFO, cfile);
 	cifs_put_tlink(tlink);
 	return rc;
 }

fs/cifs/smb2ops.c

···
 	struct fsctl_get_dfs_referral_req *dfs_req = NULL;
 	struct get_dfs_referral_rsp *dfs_rsp = NULL;
 	u32 dfs_req_size = 0, dfs_rsp_size = 0;
+	int retry_count = 0;
 
 	cifs_dbg(FYI, "%s: path: %s\n", __func__, search_name);
 
···
 				true /* is_fsctl */,
 				(char *)dfs_req, dfs_req_size, CIFSMaxBufSize,
 				(char **)&dfs_rsp, &dfs_rsp_size);
-	} while (rc == -EAGAIN);
+		if (!is_retryable_error(rc))
+			break;
+		usleep_range(512, 2048);
+	} while (++retry_count < 5);
 
 	if (rc) {
-		if ((rc != -ENOENT) && (rc != -EOPNOTSUPP))
-			cifs_tcon_dbg(VFS, "ioctl error in %s rc=%d\n", __func__, rc);
+		if (!is_retryable_error(rc) && rc != -ENOENT && rc != -EOPNOTSUPP)
+			cifs_tcon_dbg(VFS, "%s: ioctl error: rc=%d\n", __func__, rc);
 		goto out;
 	}
 

fs/cifs/smb2pdu.c

···
 	if (tcon == NULL)
 		return 0;
 
-	if (smb2_command == SMB2_TREE_CONNECT)
+	/*
+	 * Need to also skip SMB2_IOCTL because it is used for checking nested dfs links in
+	 * cifs_tree_connect().
+	 */
+	if (smb2_command == SMB2_TREE_CONNECT || smb2_command == SMB2_IOCTL)
 		return 0;
 
 	if (tcon->tidStatus == CifsExiting) {
···
 	/*
 	 * If we are reconnecting an extra channel, bind
 	 */
-	if (server->is_channel) {
+	if (CIFS_SERVER_IS_CHAN(server)) {
 		ses->binding = true;
 		ses->binding_chan = cifs_ses_find_chan(ses, server);
 	}
···
 	int rc;
 	struct cifs_ses *ses = sess_data->ses;
 	struct smb2_sess_setup_rsp *rsp = NULL;
-	char *ntlmssp_blob = NULL;
+	unsigned char *ntlmssp_blob = NULL;
 	bool use_spnego = false; /* else use raw ntlmssp */
 	u16 blob_length = 0;
 
···
 	if (rc)
 		goto out_err;
 
-	ntlmssp_blob = kmalloc(sizeof(struct _NEGOTIATE_MESSAGE),
-			       GFP_KERNEL);
-	if (ntlmssp_blob == NULL) {
-		rc = -ENOMEM;
-		goto out;
-	}
+	rc = build_ntlmssp_negotiate_blob(&ntlmssp_blob,
+					  &blob_length, ses,
+					  sess_data->nls_cp);
+	if (rc)
+		goto out_err;
 
-	build_ntlmssp_negotiate_blob(ntlmssp_blob, ses);
 	if (use_spnego) {
 		/* BB eventually need to add this */
 		cifs_dbg(VFS, "spnego not supported for SMB2 yet\n");
 		rc = -EOPNOTSUPP;
 		goto out;
-	} else {
-		blob_length = sizeof(struct _NEGOTIATE_MESSAGE);
-		/* with raw NTLMSSP we don't encapsulate in SPNEGO */
 	}
 	sess_data->iov[1].iov_base = ntlmssp_blob;
 	sess_data->iov[1].iov_len = blob_length;
···
 	cifs_small_buf_release(req);
 	rsp = (struct smb2_tree_connect_rsp *)rsp_iov.iov_base;
 	trace_smb3_tcon(xid, tcon->tid, ses->Suid, tree, rc);
-	if (rc != 0) {
+	if ((rc != 0) || (rsp == NULL)) {
 		cifs_stats_fail_inc(tcon, SMB2_TREE_CONNECT_HE);
 		tcon->need_reconnect = true;
 		goto tcon_error_exit;
···
 		goto err_free_rsp_buf;
 	}
 
+	/*
+	 * Although unlikely to be possible for rsp to be null and rc not set,
+	 * adding check below is slightly safer long term (and quiets Coverity
+	 * warning)
+	 */
 	rsp = (struct smb2_create_rsp *)rsp_iov.iov_base;
+	if (rsp == NULL) {
+		rc = -EIO;
+		kfree(pc_buf);
+		goto err_free_req;
+	}
+
 	trace_smb3_posix_mkdir_done(xid, le64_to_cpu(rsp->PersistentFileId),
 				    tcon->tid,
 				    ses->Suid, CREATE_NOT_FILE,
···
 			tcon->need_reconnect = true;
 		}
 		goto creat_exit;
-	} else
+	} else if (rsp == NULL) /* unlikely to happen, but safer to check */
+		goto creat_exit;
+	else
 		trace_smb3_open_done(xid, le64_to_cpu(rsp->PersistentFileId),
 				     tcon->tid,
 				     ses->Suid, oparms->create_options,
···
 	/* check if caller wants to look at return data or just return rc */
 	if ((plen == NULL) || (out_data == NULL))
 		goto ioctl_exit;
+
+	/*
+	 * Although unlikely to be possible for rsp to be null and rc not set,
+	 * adding check below is slightly safer long term (and quiets Coverity
+	 * warning)
+	 */
+	if (rsp == NULL) {
+		rc = -EIO;
+		goto ioctl_exit;
+	}
 
 	*plen = le32_to_cpu(rsp->OutputCount);
 

fs/cifs/transport.c

···
 	if (!ses)
 		return NULL;
 
+	spin_lock(&ses->chan_lock);
 	if (!ses->binding) {
 		/* round robin */
 		if (ses->chan_count > 1) {
 			index = (uint)atomic_inc_return(&ses->chan_seq);
 			index %= ses->chan_count;
 		}
+		spin_unlock(&ses->chan_lock);
 		return ses->chans[index].server;
 	} else {
+		spin_unlock(&ses->chan_lock);
 		return cifs_ses_server(ses);
 	}
 }