CIFS: Process reconnects for SMB2 shares
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 1bf037e..48c04b2 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -127,7 +127,132 @@
smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon)
{
int rc = 0;
- /* BB add missing code here */
+ struct nls_table *nls_codepage;
+ struct cifs_ses *ses;
+ struct TCP_Server_Info *server;
+
+ /*
+ * SMB2s NegProt, SessSetup, Logoff do not have tcon yet so
+ * check for tcp and smb session status done differently
+ * for those three - in the calling routine.
+ */
+ if (tcon == NULL)
+ return rc;
+
+ if (smb2_command == SMB2_TREE_CONNECT)
+ return rc;
+
+ if (tcon->tidStatus == CifsExiting) {
+ /*
+ * only tree disconnect, open, and write,
+ * (and ulogoff which does not have tcon)
+ * are allowed as we start force umount.
+ */
+ if ((smb2_command != SMB2_WRITE) &&
+ (smb2_command != SMB2_CREATE) &&
+ (smb2_command != SMB2_TREE_DISCONNECT)) {
+ cFYI(1, "can not send cmd %d while umounting",
+ smb2_command);
+ return -ENODEV;
+ }
+ }
+ if ((!tcon->ses) || (tcon->ses->status == CifsExiting) ||
+ (!tcon->ses->server))
+ return -EIO;
+
+ ses = tcon->ses;
+ server = ses->server;
+
+ /*
+ * Give demultiplex thread up to 10 seconds to reconnect, should be
+ * greater than cifs socket timeout which is 7 seconds
+ */
+ while (server->tcpStatus == CifsNeedReconnect) {
+ /*
+ * Return to caller for TREE_DISCONNECT and LOGOFF and CLOSE
+ * here since they are implicitly done when session drops.
+ */
+ switch (smb2_command) {
+ /*
+ * BB Should we keep oplock break and add flush to exceptions?
+ */
+ case SMB2_TREE_DISCONNECT:
+ case SMB2_CANCEL:
+ case SMB2_CLOSE:
+ case SMB2_OPLOCK_BREAK:
+ return -EAGAIN;
+ }
+
+ wait_event_interruptible_timeout(server->response_q,
+ (server->tcpStatus != CifsNeedReconnect), 10 * HZ);
+
+ /* are we still trying to reconnect? */
+ if (server->tcpStatus != CifsNeedReconnect)
+ break;
+
+ /*
+ * on "soft" mounts we wait once. Hard mounts keep
+ * retrying until process is killed or server comes
+ * back on-line
+ */
+ if (!tcon->retry) {
+ cFYI(1, "gave up waiting on reconnect in smb_init");
+ return -EHOSTDOWN;
+ }
+ }
+
+ if (!tcon->ses->need_reconnect && !tcon->need_reconnect)
+ return rc;
+
+ nls_codepage = load_nls_default();
+
+ /*
+ * need to prevent multiple threads trying to simultaneously reconnect
+ * the same SMB session
+ */
+ mutex_lock(&tcon->ses->session_mutex);
+ rc = cifs_negotiate_protocol(0, tcon->ses);
+ if (!rc && tcon->ses->need_reconnect)
+ rc = cifs_setup_session(0, tcon->ses, nls_codepage);
+
+ if (rc || !tcon->need_reconnect) {
+ mutex_unlock(&tcon->ses->session_mutex);
+ goto out;
+ }
+
+ cifs_mark_open_files_invalid(tcon);
+ rc = SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nls_codepage);
+ mutex_unlock(&tcon->ses->session_mutex);
+ cFYI(1, "reconnect tcon rc = %d", rc);
+ if (rc)
+ goto out;
+ atomic_inc(&tconInfoReconnectCount);
+ /*
+ * BB FIXME add code to check if wsize needs update due to negotiated
+ * smb buffer size shrinking.
+ */
+out:
+ /*
+ * Check if handle based operation so we know whether we can continue
+ * or not without returning to caller to reset file handle.
+ */
+ /*
+ * BB Is flush done by server on drop of tcp session? Should we special
+ * case it and skip above?
+ */
+ switch (smb2_command) {
+ case SMB2_FLUSH:
+ case SMB2_READ:
+ case SMB2_WRITE:
+ case SMB2_LOCK:
+ case SMB2_IOCTL:
+ case SMB2_QUERY_DIRECTORY:
+ case SMB2_CHANGE_NOTIFY:
+ case SMB2_QUERY_INFO:
+ case SMB2_SET_INFO:
+ return -EAGAIN;
+ }
+ unload_nls(nls_codepage);
return rc;
}