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

*** 19,29 ****
   * 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.
   */
  
  /*
   * SMB: nt_cancel
   *
--- 19,30 ----
   * CDDL HEADER END
   */
  /*
   * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
!  *
!  * Copyright 2017 Nexenta Systems, Inc.  All rights reserved.
   */
  
  /*
   * SMB: nt_cancel
   *
*** 45,69 ****
  #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);
          return (SDRC_SUCCESS);
  }
  
  void
  smb_post_nt_cancel(smb_request_t *sr)
  {
!         DTRACE_SMB_1(op__NtCancel__done, smb_request_t *, sr);
  }
  
  smb_sdrc_t
  smb_com_nt_cancel(smb_request_t *sr)
  {
          struct smb_request *req;
          struct smb_session *session;
  
          session = sr->session;
  
          smb_slist_enter(&session->s_req_list);
          req = smb_slist_head(&session->s_req_list);
--- 46,78 ----
  #include <smbsrv/smb_kproto.h>
  
  smb_sdrc_t
  smb_pre_nt_cancel(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_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);
*** 73,84 ****
--- 82,113 ----
                      (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);
  }