Fix for very subtle POSIX lock interaction race condition found by

Herb. We need to unlock POSIX locks before notifying pending lock
processes.
Jeremy.
(This used to be commit eb861e9d0fd79bbd9401ced8e55fe603c2aa7c1e)

2 files changed, 40 insertions, 9 deletions

diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
index 4cd885f1a6..20d76c9c79 100644
--- a/source3/locking/brlock.c
+++ b/source3/locking/brlock.c
@@ -414,7 +414,9 @@ static BOOL brl_pending_overlap(struct lock_struct *lock, struct lock_struct *pe
 BOOL brl_unlock(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
 		uint16 smbpid, pid_t pid, uint16 tid,
 		br_off start, br_off size,
-		BOOL remove_pending_locks_only)
+		BOOL remove_pending_locks_only,
+		void (*pre_unlock_fn)(void *),
+		void *pre_unlock_data)
 {
 	TDB_DATA kbuf, dbuf;
 	int count, i, j;
@@ -450,6 +452,10 @@ BOOL brl_unlock(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
 		    lock->fnum == fnum &&
 		    lock->start == start &&
 		    lock->size == size) {
+
+			if (pre_unlock_fn)
+				(*pre_unlock_fn)(pre_unlock_data);
+
 			/* found it - delete it */
 			if (count == 1) {
 				tdb_delete(tdb, kbuf);
@@ -483,6 +489,11 @@ BOOL brl_unlock(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
 				continue;
 
 			if (lock->lock_type != PENDING_LOCK) {
+
+				/* Do any POSIX unlocks needed. */
+				if (pre_unlock_fn)
+					(*pre_unlock_fn)(pre_unlock_data);
+
 				/* Send unlock messages to any pending waiters that overlap. */
 				for (j=0; j<count; j++) {
 					struct lock_struct *pend_lock = &locks[j];
diff --git a/source3/locking/locking.c b/source3/locking/locking.c
index 651f905e15..1b40187ac4 100644
--- a/source3/locking/locking.c
+++ b/source3/locking/locking.c
@@ -132,7 +132,8 @@ static NTSTATUS do_lock(files_struct *fsp,connection_struct *conn, uint16 lock_p
 				 */
 				(void)brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
 								lock_pid, sys_getpid(), conn->cnum, 
-								offset, count, False);
+								offset, count, False,
+								NULL, NULL);
 			}
 		}
 	}
@@ -175,6 +176,25 @@ NTSTATUS do_lock_spin(files_struct *fsp,connection_struct *conn, uint16 lock_pid
 	return ret;
 }
 
+/* Struct passed to brl_unlock. */
+struct posix_unlock_data_struct {
+	files_struct *fsp;
+	SMB_BIG_UINT offset;
+	SMB_BIG_UINT count;
+};
+
+/****************************************************************************
+ Function passed to brl_unlock to allow POSIX unlock to be done first.
+****************************************************************************/
+
+static void posix_unlock(void *pre_data)
+{
+	struct posix_unlock_data_struct *pdata = (struct posix_unlock_data_struct *)pre_data;
+
+	if (lp_posix_locking(SNUM(pdata->fsp->conn)))
+		release_posix_lock(pdata->fsp, pdata->offset, pdata->count);
+}
+
 /****************************************************************************
  Utility function called by unlocking requests.
 ****************************************************************************/
@@ -183,6 +203,7 @@ NTSTATUS do_unlock(files_struct *fsp,connection_struct *conn, uint16 lock_pid,
 		   SMB_BIG_UINT count,SMB_BIG_UINT offset)
 {
 	BOOL ok = False;
+	struct posix_unlock_data_struct posix_data;
 	
 	if (!lp_locking(SNUM(conn)))
 		return NT_STATUS_OK;
@@ -200,19 +221,18 @@ NTSTATUS do_unlock(files_struct *fsp,connection_struct *conn, uint16 lock_pid,
 	 * match then don't bother looking to remove POSIX locks.
 	 */
 
+	posix_data.fsp = fsp;
+	posix_data.offset = offset;
+	posix_data.count = count;
+
 	ok = brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
-			lock_pid, sys_getpid(), conn->cnum, offset, count, False);
+			lock_pid, sys_getpid(), conn->cnum, offset, count,
+			False, posix_unlock, (void *)&posix_data);
    
 	if (!ok) {
 		DEBUG(10,("do_unlock: returning ERRlock.\n" ));
 		return NT_STATUS_RANGE_NOT_LOCKED;
 	}
-
-	if (!lp_posix_locking(SNUM(conn)))
-		return NT_STATUS_OK;
-
-	(void)release_posix_lock(fsp, offset, count);
-
 	return NT_STATUS_OK;
 }