smb3: cleanup and clarify status of tree connections

Currently the way the tid (tree connection) status is tracked
is confusing.  The same enum is used for structs cifs_tcon
and cifs_ses and TCP_Server_info, but each of these three has
different states that they transition among.  The current
code also unnecessarily uses camelCase.

Convert from use of statusEnum to a new tid_status_enum for
tree connections.  The valid states for a tid are:

        TID_NEW = 0,
        TID_GOOD,
        TID_EXITING,
        TID_NEED_RECON,
        TID_NEED_TCON,
        TID_IN_TCON,
        TID_NEED_FILES_INVALIDATE, /* unused, considering removing in future */
        TID_IN_FILES_INVALIDATE

It also removes CifsNeedTcon, CifsInTcon, CifsNeedFilesInvalidate and
CifsInFilesInvalidate from the statusEnum used for session and
TCP_Server_Info since they are not relevant for those.

A follow on patch will fix the places where we use the
tcon->need_reconnect flag to be more consistent with the tid->status.

Also fixes a bug that was:
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifs_debug.c

@@ -94,7 +94,7 @@ static void cifs_debug_tcon(struct seq_file *m, struct cifs_tcon *tcon)
 		   le32_to_cpu(tcon->fsDevInfo.DeviceCharacteristics),
 		   le32_to_cpu(tcon->fsAttrInfo.Attributes),
 		   le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength),
-		   tcon->tidStatus);
+		   tcon->status);
 	if (dev_type == FILE_DEVICE_DISK)
 		seq_puts(m, " type: DISK ");
 	else if (dev_type == FILE_DEVICE_CD_ROM)

fs/cifs/cifsfs.c

@@ -699,14 +699,14 @@ static void cifs_umount_begin(struct super_block *sb)
 	tcon = cifs_sb_master_tcon(cifs_sb);
 
 	spin_lock(&cifs_tcp_ses_lock);
-	if ((tcon->tc_count > 1) || (tcon->tidStatus == CifsExiting)) {
+	if ((tcon->tc_count > 1) || (tcon->status == TID_EXITING)) {
 		/* we have other mounts to same share or we have
 		   already tried to force umount this and woken up
 		   all waiting network requests, nothing to do */
 		spin_unlock(&cifs_tcp_ses_lock);
 		return;
 	} else if (tcon->tc_count == 1)
-		tcon->tidStatus = CifsExiting;
+		tcon->status = TID_EXITING;
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	/* cancel_brl_requests(tcon); */ /* BB mark all brl mids as exiting */

fs/cifs/cifsglob.h

@@ -115,10 +115,18 @@ enum statusEnum {
 	CifsInNegotiate,
 	CifsNeedSessSetup,
 	CifsInSessSetup,
-	CifsNeedTcon,
-	CifsInTcon,
-	CifsNeedFilesInvalidate,
-	CifsInFilesInvalidate
+};
+
+/* associated with each tree connection to the server */
+enum tid_status_enum {
+	TID_NEW = 0,
+	TID_GOOD,
+	TID_EXITING,
+	TID_NEED_RECON,
+	TID_NEED_TCON,
+	TID_IN_TCON,
+	TID_NEED_FILES_INVALIDATE, /* currently unused */
+	TID_IN_FILES_INVALIDATE
 };
 
 enum securityEnum {
@@ -1032,7 +1040,7 @@ struct cifs_tcon {
 	char *password;		/* for share-level security */
 	__u32 tid;		/* The 4 byte tree id */
 	__u16 Flags;		/* optional support bits */
-	enum statusEnum tidStatus;
+	enum tid_status_enum status;
 	atomic_t num_smbs_sent;
 	union {
 		struct {

fs/cifs/cifssmb.c

@@ -75,12 +75,11 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon)
 
 	/* only send once per connect */
 	spin_lock(&cifs_tcp_ses_lock);
-	if (tcon->ses->status != CifsGood ||
-	    tcon->tidStatus != CifsNeedReconnect) {
+	if ((tcon->ses->status != CifsGood) || (tcon->status != TID_NEED_RECON)) {
 		spin_unlock(&cifs_tcp_ses_lock);
 		return;
 	}
-	tcon->tidStatus = CifsInFilesInvalidate;
+	tcon->status = TID_IN_FILES_INVALIDATE;
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	/* list all files open on tree connection and mark them invalid */
@@ -100,8 +99,8 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon)
 	mutex_unlock(&tcon->crfid.fid_mutex);
 
 	spin_lock(&cifs_tcp_ses_lock);
-	if (tcon->tidStatus == CifsInFilesInvalidate)
-		tcon->tidStatus = CifsNeedTcon;
+	if (tcon->status == TID_IN_FILES_INVALIDATE)
+		tcon->status = TID_NEED_TCON;
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	/*
@@ -136,7 +135,7 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
 	 * have tcon) are allowed as we start force umount
 	 */
 	spin_lock(&cifs_tcp_ses_lock);
-	if (tcon->tidStatus == CifsExiting) {
+	if (tcon->status == TID_EXITING) {
 		if (smb_command != SMB_COM_WRITE_ANDX &&
 		    smb_command != SMB_COM_OPEN_ANDX &&
 		    smb_command != SMB_COM_TREE_DISCONNECT) {

fs/cifs/connect.c

@@ -245,7 +245,7 @@ cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server,
 
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 			tcon->need_reconnect = true;
-			tcon->tidStatus = CifsNeedReconnect;
+			tcon->status = TID_NEED_RECON;
 		}
 		if (ses->tcon_ipc)
 			ses->tcon_ipc->need_reconnect = true;
@@ -2207,7 +2207,7 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
 
 static int match_tcon(struct cifs_tcon *tcon, struct smb3_fs_context *ctx)
 {
-	if (tcon->tidStatus == CifsExiting)
+	if (tcon->status == TID_EXITING)
 		return 0;
 	if (strncmp(tcon->treeName, ctx->UNC, MAX_TREE_SIZE))
 		return 0;
@@ -4486,12 +4486,12 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
 	/* only send once per connect */
 	spin_lock(&cifs_tcp_ses_lock);
 	if (tcon->ses->status != CifsGood ||
-	    (tcon->tidStatus != CifsNew &&
-	    tcon->tidStatus != CifsNeedTcon)) {
+	    (tcon->status != TID_NEW &&
+	    tcon->status != TID_NEED_TCON)) {
 		spin_unlock(&cifs_tcp_ses_lock);
 		return 0;
 	}
-	tcon->tidStatus = CifsInTcon;
+	tcon->status = TID_IN_TCON;
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
@@ -4532,13 +4532,13 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
 
 	if (rc) {
 		spin_lock(&cifs_tcp_ses_lock);
-		if (tcon->tidStatus == CifsInTcon)
-			tcon->tidStatus = CifsNeedTcon;
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_NEED_TCON;
 		spin_unlock(&cifs_tcp_ses_lock);
 	} else {
 		spin_lock(&cifs_tcp_ses_lock);
-		if (tcon->tidStatus == CifsInTcon)
-			tcon->tidStatus = CifsGood;
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_GOOD;
 		spin_unlock(&cifs_tcp_ses_lock);
 		tcon->need_reconnect = false;
 	}
@@ -4554,24 +4554,24 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
 	/* only send once per connect */
 	spin_lock(&cifs_tcp_ses_lock);
 	if (tcon->ses->status != CifsGood ||
-	    (tcon->tidStatus != CifsNew &&
-	    tcon->tidStatus != CifsNeedTcon)) {
+	    (tcon->status != TID_NEW &&
+	    tcon->status != TID_NEED_TCON)) {
 		spin_unlock(&cifs_tcp_ses_lock);
 		return 0;
 	}
-	tcon->tidStatus = CifsInTcon;
+	tcon->status = TID_IN_TCON;
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	rc = ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, nlsc);
 	if (rc) {
 		spin_lock(&cifs_tcp_ses_lock);
-		if (tcon->tidStatus == CifsInTcon)
-			tcon->tidStatus = CifsNeedTcon;
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_NEED_TCON;
 		spin_unlock(&cifs_tcp_ses_lock);
 	} else {
 		spin_lock(&cifs_tcp_ses_lock);
-		if (tcon->tidStatus == CifsInTcon)
-			tcon->tidStatus = CifsGood;
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_GOOD;
 		spin_unlock(&cifs_tcp_ses_lock);
 		tcon->need_reconnect = false;
 	}

fs/cifs/misc.c

@@ -116,7 +116,7 @@ tconInfoAlloc(void)
 	}
 
 	atomic_inc(&tconInfoAllocCount);
-	ret_buf->tidStatus = CifsNew;
+	ret_buf->status = TID_NEW;
 	++ret_buf->tc_count;
 	INIT_LIST_HEAD(&ret_buf->openFileList);
 	INIT_LIST_HEAD(&ret_buf->tcon_list);

fs/cifs/smb2pdu.c

@@ -163,7 +163,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
 		return 0;
 
 	spin_lock(&cifs_tcp_ses_lock);
-	if (tcon->tidStatus == CifsExiting) {
+	if (tcon->status == TID_EXITING) {
 		/*
 		 * only tree disconnect, open, and write,
 		 * (and ulogoff which does not have tcon)
@@ -3860,7 +3860,7 @@ void smb2_reconnect_server(struct work_struct *work)
 		goto done;
 	}
 
-	tcon->tidStatus = CifsGood;
+	tcon->status = TID_GOOD;
 	tcon->retry = false;
 	tcon->need_reconnect = false;