NEX-1643 dtrace provider for smbsrv
Reviewed by: Evan Layton <evan.layton@nexenta.com>
Reviewed by: Matt Barden <matt.barden@nexenta.com>
NEX-9864 Some SMB cancel races remain after NEX-5845
Revert (part of) "NEX-5845 rework SMB immediate cancel"
reverts (part of) commit 7a5da69f6d42b17ebcc95ca3d02925d07a01343e.
Reviewed by: Matt Barden <matt.barden@nexenta.com>
Reviewed by: Evan Layton <evan.layton@nexenta.com>
NEX-5845 rework SMB immediate cancel
Reviewed by: Matt Barden <matt.barden@nexenta.com>
Reviewed by: Kevin Crowe <kevin.crowe@nexenta.com>
NEX-5152 immediate SMB cancel may fail
Reviewed by: Kevin Crowe <kevin.crowe@nexenta.com>
Reviewed by: Matt Barden <Matt.Barden@nexenta.com>
re #13470 rb4432 Sync some SMB differences from illumos
re #11215 rb3676 sesctl to SGI JBOD hangs in biowait() with a command stuck in mptsas driver
re #10734 NT Trans. Notify returning too quickly

@@ -19,11 +19,12 @@
  * CDDL HEADER END
  */
 /*
  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
- * Copyright 2012 Nexenta Systems, Inc.  All rights reserved.
+ *
+ * Copyright 2017 Nexenta Systems, Inc.  All rights reserved.
  */
 
 /*
  * SMB: nt_cancel
  *

@@ -45,25 +46,33 @@
 #include <smbsrv/smb_kproto.h>
 
 smb_sdrc_t
 smb_pre_nt_cancel(smb_request_t *sr)
 {
-        DTRACE_SMB_1(op__NtCancel__start, smb_request_t *, sr);
+        DTRACE_SMB_START(op__NtCancel, smb_request_t *, sr);
         return (SDRC_SUCCESS);
 }
 
 void
 smb_post_nt_cancel(smb_request_t *sr)
 {
-        DTRACE_SMB_1(op__NtCancel__done, smb_request_t *, sr);
+        DTRACE_SMB_DONE(op__NtCancel, smb_request_t *, sr);
 }
 
+/*
+ * Dispatch handler for SMB_COM_NT_CANCEL.
+ * Note that Cancel does NOT get a response.
+ *
+ * SMB NT Cancel has an inherent race with the request being
+ * cancelled.  See comments at smb_request_cancel().
+ */
 smb_sdrc_t
 smb_com_nt_cancel(smb_request_t *sr)
 {
         struct smb_request *req;
         struct smb_session *session;
+        int cnt = 0;
 
         session = sr->session;
 
         smb_slist_enter(&session->s_req_list);
         req = smb_slist_head(&session->s_req_list);

@@ -73,12 +82,32 @@
                     (req->smb_uid == sr->smb_uid) &&
                     (req->smb_pid == sr->smb_pid) &&
                     (req->smb_tid == sr->smb_tid) &&
                     (req->smb_mid == sr->smb_mid)) {
                         smb_request_cancel(req);
+                        cnt++;
                 }
                 req = smb_slist_next(&session->s_req_list, req);
         }
+        if (cnt != 1) {
+                DTRACE_PROBE2(smb__ntcancel__error,
+                    uint16_t, sr->smb_mid, int, cnt);
+        }
         smb_slist_exit(&session->s_req_list);
 
         return (SDRC_NO_REPLY);
+}
+
+/*
+ * This handles an SMB_COM_NT_CANCEL request when seen in the reader.
+ * (See smb1sr_newrq)  Handle this immediately, rather than
+ * going through the normal taskq dispatch mechanism.
+ * Note that Cancel does NOT get a response.
+ */
+int
+smb1sr_newrq_cancel(smb_request_t *sr)
+{
+        (void) smb_pre_nt_cancel(sr);
+        (void) smb_com_nt_cancel(sr);
+        smb_post_nt_cancel(sr);
+        return (0);
 }