1 files changed, 50 insertions, 38 deletions

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index d2307162a2de..adf8758847f6 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -657,6 +657,19 @@ static bool
 server_unresponsive(struct TCP_Server_Info *server)
 {
 	/*
+	 * If we're in the process of mounting a share or reconnecting a session
+	 * and the server abruptly shut down (e.g. socket wasn't closed, packet
+	 * had been ACK'ed but no SMB response), don't wait longer than 20s to
+	 * negotiate protocol.
+	 */
+	spin_lock(&server->srv_lock);
+	if (server->tcpStatus == CifsInNegotiate &&
+	    time_after(jiffies, server->lstrp + 20 * HZ)) {
+		spin_unlock(&server->srv_lock);
+		cifs_reconnect(server, false);
+		return true;
+	}
+	/*
 	 * We need to wait 3 echo intervals to make sure we handle such
 	 * situations right:
 	 * 1s  client sends a normal SMB request
@@ -667,7 +680,6 @@ server_unresponsive(struct TCP_Server_Info *server)
 	 * 65s kernel_recvmsg times out, and we see that we haven't gotten
 	 *     a response in >60s.
 	 */
-	spin_lock(&server->srv_lock);
 	if ((server->tcpStatus == CifsGood ||
 	    server->tcpStatus == CifsNeedNegotiate) &&
 	    (!server->ops->can_echo || server->ops->can_echo(server)) &&
@@ -799,13 +811,9 @@ cifs_read_iter_from_socket(struct TCP_Server_Info *server, struct iov_iter *iter
 			   unsigned int to_read)
 {
 	struct msghdr smb_msg = { .msg_iter = *iter };
-	int ret;
 
 	iov_iter_truncate(&smb_msg.msg_iter, to_read);
-	ret = cifs_readv_from_socket(server, &smb_msg);
-	if (ret > 0)
-		iov_iter_advance(iter, ret);
-	return ret;
+	return cifs_readv_from_socket(server, &smb_msg);
 }
 
 static bool
@@ -997,11 +1005,10 @@ clean_demultiplex_info(struct TCP_Server_Info *server)
 	}
 
 	if (!list_empty(&server->pending_mid_q)) {
-		struct list_head dispose_list;
 		struct mid_q_entry *mid_entry;
 		struct list_head *tmp, *tmp2;
+		LIST_HEAD(dispose_list);
 
-		INIT_LIST_HEAD(&dispose_list);
 		spin_lock(&server->mid_lock);
 		list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
 			mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
@@ -1519,6 +1526,9 @@ static int match_server(struct TCP_Server_Info *server,
 	if (server->nosharesock)
 		return 0;
 
+	if (!match_super && (ctx->dfs_conn || server->dfs_conn))
+		return 0;
+
 	/* If multidialect negotiation see if existing sessions match one */
 	if (strcmp(ctx->vals->version_string, SMB3ANY_VERSION_STRING) == 0) {
 		if (server->vals->protocol_id < SMB30_PROT_ID)
@@ -1712,6 +1722,7 @@ cifs_get_tcp_session(struct smb3_fs_context *ctx,
 
 	if (ctx->nosharesock)
 		tcp_ses->nosharesock = true;
+	tcp_ses->dfs_conn = ctx->dfs_conn;
 
 	tcp_ses->ops = ctx->ops;
 	tcp_ses->vals = ctx->vals;
@@ -1862,13 +1873,15 @@ out_err:
 }
 
 /* this function must be called with ses_lock and chan_lock held */
-static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
+static int match_session(struct cifs_ses *ses,
+			 struct smb3_fs_context *ctx,
+			 bool match_super)
 {
 	if (ctx->sectype != Unspecified &&
 	    ctx->sectype != ses->sectype)
 		return 0;
 
-	if (ctx->dfs_root_ses != ses->dfs_root_ses)
+	if (!match_super && ctx->dfs_root_ses != ses->dfs_root_ses)
 		return 0;
 
 	/*
@@ -1987,7 +2000,7 @@ cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
 			continue;
 		}
 		spin_lock(&ses->chan_lock);
-		if (match_session(ses, ctx)) {
+		if (match_session(ses, ctx, false)) {
 			spin_unlock(&ses->chan_lock);
 			spin_unlock(&ses->ses_lock);
 			ret = ses;
@@ -2047,8 +2060,7 @@ void __cifs_put_smb_ses(struct cifs_ses *ses)
 	if (do_logoff) {
 		xid = get_xid();
 		rc = server->ops->logoff(xid, ses);
-		if (rc)
-			cifs_server_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
+		cifs_server_dbg(FYI, "%s: Session Logoff: rc=%d\n",
 				__func__, rc);
 		_free_xid(xid);
 	}
@@ -2371,8 +2383,6 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
 	 * need to lock before changing something in the session.
 	 */
 	spin_lock(&cifs_tcp_ses_lock);
-	if (ctx->dfs_root_ses)
-		cifs_smb_ses_inc_refcount(ctx->dfs_root_ses);
 	ses->dfs_root_ses = ctx->dfs_root_ses;
 	list_add(&ses->smb_ses_list, &server->smb_ses_list);
 	spin_unlock(&cifs_tcp_ses_lock);
@@ -2447,6 +2457,7 @@ cifs_put_tcon(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
 {
 	unsigned int xid;
 	struct cifs_ses *ses;
+	LIST_HEAD(ses_list);
 
 	/*
 	 * IPC tcon share the lifetime of their session and are
@@ -2471,6 +2482,9 @@ cifs_put_tcon(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
 
 	list_del_init(&tcon->tcon_list);
 	tcon->status = TID_EXITING;
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	list_replace_init(&tcon->dfs_ses_list, &ses_list);
+#endif
 	spin_unlock(&tcon->tc_lock);
 	spin_unlock(&cifs_tcp_ses_lock);
 
@@ -2498,6 +2512,9 @@ cifs_put_tcon(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
 	cifs_fscache_release_super_cookie(tcon);
 	tconInfoFree(tcon, netfs_trace_tcon_ref_free);
 	cifs_put_smb_ses(ses);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	dfs_put_root_smb_sessions(&ses_list);
+#endif
 }
 
 /**
@@ -2881,7 +2898,7 @@ cifs_match_super(struct super_block *sb, void *data)
 	spin_lock(&ses->chan_lock);
 	spin_lock(&tcon->tc_lock);
 	if (!match_server(tcp_srv, ctx, true) ||
-	    !match_session(ses, ctx) ||
+	    !match_session(ses, ctx, true) ||
 	    !match_tcon(tcon, ctx) ||
 	    !match_prepath(sb, tcon, mnt_data)) {
 		rc = 0;
@@ -3612,13 +3629,12 @@ out:
 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
 {
 	struct cifs_mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
-	bool isdfs;
 	int rc;
 
-	rc = dfs_mount_share(&mnt_ctx, &isdfs);
+	rc = dfs_mount_share(&mnt_ctx);
 	if (rc)
 		goto error;
-	if (!isdfs)
+	if (!ctx->dfs_conn)
 		goto out;
 
 	/*
@@ -4023,7 +4039,7 @@ cifs_set_vol_auth(struct smb3_fs_context *ctx, struct cifs_ses *ses)
 }
 
 static struct cifs_tcon *
-__cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
+cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
 {
 	int rc;
 	struct cifs_tcon *master_tcon = cifs_sb_master_tcon(cifs_sb);
@@ -4069,7 +4085,7 @@ __cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
 
 	ses = cifs_get_smb_ses(master_tcon->ses->server, ctx);
 	if (IS_ERR(ses)) {
-		tcon = (struct cifs_tcon *)ses;
+		tcon = ERR_CAST(ses);
 		cifs_put_tcp_session(master_tcon->ses->server, 0);
 		goto out;
 	}
@@ -4121,17 +4137,6 @@ out:
 	return tcon;
 }
 
-static struct cifs_tcon *
-cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
-{
-	struct cifs_tcon *ret;
-
-	cifs_mount_lock();
-	ret = __cifs_construct_tcon(cifs_sb, fsuid);
-	cifs_mount_unlock();
-	return ret;
-}
-
 struct cifs_tcon *
 cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
 {
@@ -4194,13 +4199,16 @@ tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink)
  *
  * If one doesn't exist then insert a new tcon_link struct into the tree and
  * try to construct a new one.
+ *
+ * REMEMBER to call cifs_put_tlink() after successful calls to cifs_sb_tlink,
+ * to avoid refcount issues
  */
 struct tcon_link *
 cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
 {
-	int ret;
-	kuid_t fsuid = current_fsuid();
 	struct tcon_link *tlink, *newtlink;
+	kuid_t fsuid = current_fsuid();
+	int err;
 
 	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
 		return cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
@@ -4235,9 +4243,9 @@ cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
 		spin_unlock(&cifs_sb->tlink_tree_lock);
 	} else {
 wait_for_construction:
-		ret = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
+		err = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
 				  TASK_INTERRUPTIBLE);
-		if (ret) {
+		if (err) {
 			cifs_put_tlink(tlink);
 			return ERR_PTR(-ERESTARTSYS);
 		}
@@ -4248,8 +4256,9 @@ wait_for_construction:
 
 		/* return error if we tried this already recently */
 		if (time_before(jiffies, tlink->tl_time + TLINK_ERROR_EXPIRE)) {
+			err = PTR_ERR(tlink->tl_tcon);
 			cifs_put_tlink(tlink);
-			return ERR_PTR(-EACCES);
+			return ERR_PTR(err);
 		}
 
 		if (test_and_set_bit(TCON_LINK_PENDING, &tlink->tl_flags))
@@ -4261,8 +4270,11 @@ wait_for_construction:
 	wake_up_bit(&tlink->tl_flags, TCON_LINK_PENDING);
 
 	if (IS_ERR(tlink->tl_tcon)) {
+		err = PTR_ERR(tlink->tl_tcon);
+		if (err == -ENOKEY)
+			err = -EACCES;
 		cifs_put_tlink(tlink);
-		return ERR_PTR(-EACCES);
+		return ERR_PTR(err);
 	}
 
 	return tlink;