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, 21 insertions, 5 deletions

diff --git a/source3/include/proto.h b/source3/include/proto.h
index 34104727e9..ed2c50af2f 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -3379,8 +3379,14 @@ struct packet_struct *receive_unexpected(enum packet_type packet_type, int id,
 
 bool brl_same_context(const struct lock_context *ctx1, 
 			     const struct lock_context *ctx2);
+NTSTATUS brl_lock_failed(files_struct *fsp, const struct lock_struct *lock, bool blocking_lock);
 void brl_init(bool read_only);
 void brl_shutdown(void);
+
+NTSTATUS brl_lock_windows_default(struct byte_range_lock *br_lck,
+		struct lock_struct *plock,
+		bool blocking_lock);
+
 NTSTATUS brl_lock(struct messaging_context *msg_ctx,
 		struct byte_range_lock *br_lck,
 		uint32 smbpid,
@@ -3390,7 +3396,8 @@ NTSTATUS brl_lock(struct messaging_context *msg_ctx,
 		enum brl_type lock_type,
 		enum brl_flavour lock_flav,
 		bool blocking_lock,
-		uint32 *psmbpid);
+		uint32 *psmbpid,
+		struct blocking_lock_record *blr);
 bool brl_unlock(struct messaging_context *msg_ctx,
 		struct byte_range_lock *br_lck,
 		uint32 smbpid,
@@ -3398,6 +3405,9 @@ bool brl_unlock(struct messaging_context *msg_ctx,
 		br_off start,
 		br_off size,
 		enum brl_flavour lock_flav);
+bool brl_unlock_windows_default(struct messaging_context *msg_ctx,
+			       struct byte_range_lock *br_lck,
+			       const struct lock_struct *plock);
 bool brl_locktest(struct byte_range_lock *br_lck,
 		uint32 smbpid,
 		struct server_id pid,
@@ -3417,7 +3427,10 @@ bool brl_lock_cancel(struct byte_range_lock *br_lck,
 		struct server_id pid,
 		br_off start,
 		br_off size,
-		enum brl_flavour lock_flav);
+		enum brl_flavour lock_flav,
+		struct blocking_lock_record *blr);
+bool brl_lock_cancel_default(struct byte_range_lock *br_lck,
+		struct lock_struct *plock);
 void brl_close_fnum(struct messaging_context *msg_ctx,
 		    struct byte_range_lock *br_lck);
 int brl_forall(void (*fn)(struct file_id id, struct server_id pid,
@@ -3456,7 +3469,8 @@ 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);
 NTSTATUS do_unlock(struct messaging_context *msg_ctx,
 			files_struct *fsp,
 			uint32 lock_pid,
@@ -3467,7 +3481,8 @@ 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);
 void locking_close_file(struct messaging_context *msg_ctx,
 			files_struct *fsp);
 bool locking_init(void);
@@ -6342,6 +6357,7 @@ void smbd_aio_complete_mid(unsigned int mid);
 
 /* The following definitions come from smbd/blocking.c  */
 
+void process_blocking_lock_queue(void);
 bool push_blocking_lock_request( struct byte_range_lock *br_lck,
 		struct smb_request *req,
 		files_struct *fsp,
@@ -6356,7 +6372,7 @@ bool push_blocking_lock_request( struct byte_range_lock *br_lck,
 void cancel_pending_lock_requests_by_fid(files_struct *fsp, struct byte_range_lock *br_lck);
 void remove_pending_lock_requests_by_mid(int mid);
 bool blocking_lock_was_deferred(int mid);
-bool blocking_lock_cancel(files_struct *fsp,
+struct blocking_lock_record *blocking_lock_cancel(files_struct *fsp,
 			uint32 lock_pid,
 			uint64_t offset,
 			uint64_t count,