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, 47 insertions, 19 deletions

diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
index edba4ed30a..d12c4affc3 100644
--- a/source3/locking/brlock.c
+++ b/source3/locking/brlock.c
@@ -228,7 +228,7 @@ static bool brl_pending_overlap(const struct lock_struct *lock, const struct loc
  app depends on this ?
 ****************************************************************************/
 
-static NTSTATUS brl_lock_failed(files_struct *fsp, const struct lock_struct *lock, bool blocking_lock)
+NTSTATUS brl_lock_failed(files_struct *fsp, const struct lock_struct *lock, bool blocking_lock)
 {
 	if (lock->start >= 0xEF000000 && (lock->start >> 63) == 0) {
 		/* amazing the little things you learn with a test
@@ -305,14 +305,16 @@ static int lock_compare(const struct lock_struct *lck1,
  Lock a range of bytes - Windows lock semantics.
 ****************************************************************************/
 
-static NTSTATUS brl_lock_windows(struct byte_range_lock *br_lck,
-			struct lock_struct *plock, bool blocking_lock)
+NTSTATUS brl_lock_windows_default(struct byte_range_lock *br_lck,
+    struct lock_struct *plock, bool blocking_lock)
 {
 	unsigned int i;
 	files_struct *fsp = br_lck->fsp;
 	struct lock_struct *locks = br_lck->lock_data;
 	NTSTATUS status;
 
+	SMB_ASSERT(plock->lock_type != UNLOCK_LOCK);
+
 	for (i=0; i < br_lck->num_locks; i++) {
 		/* Do any Windows or POSIX locks conflict ? */
 		if (brl_conflict(&locks[i], plock)) {
@@ -781,7 +783,8 @@ 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)
 {
 	NTSTATUS ret;
 	struct lock_struct lock;
@@ -807,7 +810,8 @@ NTSTATUS brl_lock(struct messaging_context *msg_ctx,
 	lock.lock_flav = lock_flav;
 
 	if (lock_flav == WINDOWS_LOCK) {
-		ret = brl_lock_windows(br_lck, &lock, blocking_lock);
+		ret = SMB_VFS_BRL_LOCK_WINDOWS(br_lck->fsp->conn, br_lck,
+		    &lock, blocking_lock, blr);
 	} else {
 		ret = brl_lock_posix(msg_ctx, br_lck, &lock);
 	}
@@ -828,7 +832,7 @@ NTSTATUS brl_lock(struct messaging_context *msg_ctx,
  Unlock a range of bytes - Windows semantics.
 ****************************************************************************/
 
-static bool brl_unlock_windows(struct messaging_context *msg_ctx,
+bool brl_unlock_windows_default(struct messaging_context *msg_ctx,
 			       struct byte_range_lock *br_lck,
 			       const struct lock_struct *plock)
 {
@@ -836,6 +840,8 @@ static bool brl_unlock_windows(struct messaging_context *msg_ctx,
 	struct lock_struct *locks = br_lck->lock_data;
 	enum brl_type deleted_lock_type = READ_LOCK; /* shut the compiler up.... */
 
+	SMB_ASSERT(plock->lock_type == UNLOCK_LOCK);
+
 #if ZERO_ZERO
 	/* Delete write locks by preference... The lock list
 	   is sorted in the zero zero case. */
@@ -1130,7 +1136,8 @@ bool brl_unlock(struct messaging_context *msg_ctx,
 	lock.lock_flav = lock_flav;
 
 	if (lock_flav == WINDOWS_LOCK) {
-		return brl_unlock_windows(msg_ctx, br_lck, &lock);
+		return SMB_VFS_BRL_UNLOCK_WINDOWS(br_lck->fsp->conn, msg_ctx,
+		    br_lck, &lock);
 	} else {
 		return brl_unlock_posix(msg_ctx, br_lck, &lock);
 	}
@@ -1266,32 +1273,54 @@ NTSTATUS brl_lockquery(struct byte_range_lock *br_lck,
 /****************************************************************************
  Remove a particular pending lock.
 ****************************************************************************/
-
 bool brl_lock_cancel(struct byte_range_lock *br_lck,
 		uint32 smbpid,
 		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 ret;
+	struct lock_struct lock;
+
+	lock.context.smbpid = smbpid;
+	lock.context.pid = pid;
+	lock.context.tid = br_lck->fsp->conn->cnum;
+	lock.start = start;
+	lock.size = size;
+	lock.fnum = br_lck->fsp->fnum;
+	lock.lock_flav = lock_flav;
+	/* lock.lock_type doesn't matter */
+
+	if (lock_flav == WINDOWS_LOCK) {
+		ret = SMB_VFS_BRL_CANCEL_WINDOWS(br_lck->fsp->conn, br_lck,
+		    &lock, blr);
+	} else {
+		ret = brl_lock_cancel_default(br_lck, &lock);
+	}
+
+	return ret;
+}
+
+bool brl_lock_cancel_default(struct byte_range_lock *br_lck,
+		struct lock_struct *plock)
 {
 	unsigned int i;
 	struct lock_struct *locks = br_lck->lock_data;
-	struct lock_context context;
 
-	context.smbpid = smbpid;
-	context.pid = pid;
-	context.tid = br_lck->fsp->conn->cnum;
+	SMB_ASSERT(plock);
 
 	for (i = 0; i < br_lck->num_locks; i++) {
 		struct lock_struct *lock = &locks[i];
 
 		/* For pending locks we *always* care about the fnum. */
-		if (brl_same_context(&lock->context, &context) &&
-				lock->fnum == br_lck->fsp->fnum &&
+		if (brl_same_context(&lock->context, &plock->context) &&
+				lock->fnum == plock->fnum &&
 				IS_PENDING_LOCK(lock->lock_type) &&
-				lock->lock_flav == lock_flav &&
-				lock->start == start &&
-				lock->size == size) {
+				lock->lock_flav == plock->lock_flav &&
+				lock->start == plock->start &&
+				lock->size == plock->size) {
 			break;
 		}
 	}
@@ -1460,7 +1489,6 @@ void brl_close_fnum(struct messaging_context *msg_ctx,
 /****************************************************************************
  Ensure this set of lock entries is valid.
 ****************************************************************************/
-
 static bool validate_lock_entries(unsigned int *pnum_entries, struct lock_struct **pplocks)
 {
 	unsigned int i;