Add VFS ops for Windows BRL: Lock, Unlock and Cancel:

This patch adds 3 new VFS OPs for Windows byte range locking: BRL_LOCK_WINDOWS,
BRL_UNLOCK_WINDOWS and BRL_CANCEL_WINDOWS. Specifically:

* I renamed brl_lock_windows, brl_unlock_windows and brl_lock_cancel to
  *_default as the default implementations of the VFS ops.
* The blocking_lock_record (BLR) is now passed into the brl_lock_windows and
  brl_cancel_windows paths. The Onefs implementation uses it - future
  implementations may find it useful too.
* Created brl_lock_cancel to do what brl_lock/brl_unlock do: set up a
  lock_struct and call either the Posix or Windows lock function. These happen
  to be the same for the default implementation.
* Added helper functions: increment_current_lock_count() and
  decrement_current_lock_count().
* Minor spelling correction in brl_timeout_fn: brl -> blr.
* Changed blocking_lock_cancel() to return the BLR that it has cancelled. This
  allows us to assert its the lock that we wanted to cancel. If this assert ever
  fires, this path will need to take in the BLR to cancel, rather than choosing
  on its own.
* Adds a small helper function: find_blocking_lock_record_by_id(). Used by the
  OneFS implementation, but could be useful for others.

1 files changed, 48 insertions, 33 deletions

diff --git a/source3/locking/locking.c b/source3/locking/locking.c
index b342fa9b1e..902b230e60 100644
--- a/source3/locking/locking.c
+++ b/source3/locking/locking.c
@@ -177,6 +177,34 @@ NTSTATUS query_lock(files_struct *fsp,
 	return status;
 }
 
+static void increment_current_lock_count(files_struct *fsp,
+    enum brl_flavour lock_flav)
+{
+	if (lock_flav == WINDOWS_LOCK &&
+	    fsp->current_lock_count != NO_LOCKING_COUNT) {
+		/* blocking ie. pending, locks also count here,
+		 * as this is an efficiency counter to avoid checking
+		 * the lock db. on close. JRA. */
+
+		fsp->current_lock_count++;
+	} else {
+		/* Notice that this has had a POSIX lock request.
+		 * We can't count locks after this so forget them.
+		 */
+		fsp->current_lock_count = NO_LOCKING_COUNT;
+	}
+}
+
+static void decrement_current_lock_count(files_struct *fsp,
+    enum brl_flavour lock_flav)
+{
+	if (lock_flav == WINDOWS_LOCK &&
+	    fsp->current_lock_count != NO_LOCKING_COUNT) {
+		SMB_ASSERT(fsp->current_lock_count > 0);
+		fsp->current_lock_count--;
+	}
+}
+
 /****************************************************************************
  Utility function called by locking requests.
 ****************************************************************************/
@@ -190,7 +218,8 @@ struct byte_range_lock *do_lock(struct messaging_context *msg_ctx,
 			enum brl_flavour lock_flav,
 			bool blocking_lock,
 			NTSTATUS *perr,
-			uint32 *plock_pid)
+			uint32 *plock_pid,
+			struct blocking_lock_record *blr)
 {
 	struct byte_range_lock *br_lck = NULL;
 
@@ -206,9 +235,11 @@ struct byte_range_lock *do_lock(struct messaging_context *msg_ctx,
 
 	/* NOTE! 0 byte long ranges ARE allowed and should be stored  */
 
-	DEBUG(10,("do_lock: lock flavour %s lock type %s start=%.0f len=%.0f requested for fnum %d file %s\n",
+	DEBUG(10,("do_lock: lock flavour %s lock type %s start=%.0f len=%.0f "
+		"blocking_lock=%s requested for fnum %d file %s\n",
 		lock_flav_name(lock_flav), lock_type_name(lock_type),
-		(double)offset, (double)count, fsp->fnum, fsp->fsp_name ));
+		(double)offset, (double)count, blocking_lock ? "true" :
+		"false", fsp->fnum, fsp->fsp_name));
 
 	br_lck = brl_get_locks(talloc_tos(), fsp);
 	if (!br_lck) {
@@ -225,22 +256,12 @@ struct byte_range_lock *do_lock(struct messaging_context *msg_ctx,
 			lock_type,
 			lock_flav,
 			blocking_lock,
-			plock_pid);
+			plock_pid,
+			blr);
 
-	if (lock_flav == WINDOWS_LOCK &&
-			fsp->current_lock_count != NO_LOCKING_COUNT) {
-		/* blocking ie. pending, locks also count here,
-		 * as this is an efficiency counter to avoid checking
-		 * the lock db. on close. JRA. */
-
-		fsp->current_lock_count++;
-	} else {
-		/* Notice that this has had a POSIX lock request.
-		 * We can't count locks after this so forget them.
-		 */
-		fsp->current_lock_count = NO_LOCKING_COUNT;
-	}
+	DEBUG(10, ("do_lock: returning status=%s\n", nt_errstr(*perr)));
 
+	increment_current_lock_count(fsp, lock_flav);
 	return br_lck;
 }
 
@@ -289,12 +310,7 @@ NTSTATUS do_unlock(struct messaging_context *msg_ctx,
 		return NT_STATUS_RANGE_NOT_LOCKED;
 	}
 
-	if (lock_flav == WINDOWS_LOCK &&
-			fsp->current_lock_count != NO_LOCKING_COUNT) {
-		SMB_ASSERT(fsp->current_lock_count > 0);
-		fsp->current_lock_count--;
-	}
-
+	decrement_current_lock_count(fsp, lock_flav);
 	return NT_STATUS_OK;
 }
 
@@ -306,11 +322,14 @@ NTSTATUS do_lock_cancel(files_struct *fsp,
 			uint32 lock_pid,
 			uint64_t count,
 			uint64_t offset,
-			enum brl_flavour lock_flav)
+			enum brl_flavour lock_flav,
+			struct blocking_lock_record *blr)
 {
 	bool ok = False;
 	struct byte_range_lock *br_lck = NULL;
-	
+
+	SMB_ASSERT(blr);
+
 	if (!fsp->can_lock) {
 		return fsp->is_directory ?
 			NT_STATUS_INVALID_DEVICE_REQUEST : NT_STATUS_INVALID_HANDLE;
@@ -333,8 +352,9 @@ NTSTATUS do_lock_cancel(files_struct *fsp,
 			procid_self(),
 			offset,
 			count,
-			lock_flav);
-   
+			lock_flav,
+			blr);
+
 	TALLOC_FREE(br_lck);
 
 	if (!ok) {
@@ -342,12 +362,7 @@ NTSTATUS do_lock_cancel(files_struct *fsp,
 		return NT_STATUS_DOS(ERRDOS, ERRcancelviolation);
 	}
 
-	if (lock_flav == WINDOWS_LOCK &&
-			fsp->current_lock_count != NO_LOCKING_COUNT) {
-		SMB_ASSERT(fsp->current_lock_count > 0);
-		fsp->current_lock_count--;
-	}
-
+	decrement_current_lock_count(fsp, lock_flav);
 	return NT_STATUS_OK;
 }