Reworked patch for bug CORE-4615 : Classic Server could hung with (near) 100% CPU load

src/jrd/Database.h

@@ -279,32 +279,6 @@ public:
 		Sync& sync;
 	};
 
-	class CheckoutIfNotInAst
-	{
-	public:
-		explicit CheckoutIfNotInAst(Database* dbb)
-			: sync(*dbb->dbb_sync)
-		{
-			inAst = sync.inAst();
-			if (!inAst)
-				sync.unlock();
-		}
-
-		~CheckoutIfNotInAst()
-		{
-			if (!inAst)
-				sync.lock();
-		}
-
-	private:
-		// copying is prohibited
-		CheckoutIfNotInAst(const CheckoutIfNotInAst&);
-		CheckoutIfNotInAst& operator=(const CheckoutIfNotInAst&);
-
-		Sync& sync;
-		bool inAst;
-	};
-
 	class CheckoutLockGuard
 	{
 	public:

src/jrd/os/posix/unix.cpp

@@ -366,9 +366,8 @@ void PIO_flush(Database* dbb, jrd_file* main_file)
 
 	// Since all SUPERSERVER_V2 database and shadow I/O is synchronous, this is a no-op.
 #ifndef SUPERSERVER_V2
+	PioCheckout dcoHolder(dbb);
 	MutexLockGuard guard(main_file->fil_mutex);
-
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
 	for (jrd_file* file = main_file; file; file = file->fil_next)
 	{
 		if (file->fil_desc != -1)
@@ -590,6 +589,8 @@ USHORT PIO_init_data(Database* dbb, jrd_file* main_file, ISC_STATUS* status_vect
 	const char* const zero_buff = zeros().getBuffer();
 	const size_t zero_buff_size = zeros().getSize();
 
+	PioCheckout dcoHolder(dbb);
+
 	// Fake buffer, used in seek_file. Page space ID have no matter there
 	// as we already know file to work with
 	BufferDesc bdb;
@@ -597,9 +598,6 @@ USHORT PIO_init_data(Database* dbb, jrd_file* main_file, ISC_STATUS* status_vect
 	bdb.bdb_page = PageNumber(0, startPage);
 
 	FB_UINT64 offset;
-
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
-
 	jrd_file* file = seek_file(main_file, &bdb, &offset, status_vector);
 
 	if (!file)
@@ -721,7 +719,7 @@ bool PIO_read(jrd_file* file, BufferDesc* bdb, Ods::pag* page, ISC_STATUS* statu
 	}
 
 	Database* dbb = bdb->bdb_dbb;
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
+	PioCheckout dcoHolder(dbb);
 
 	const FB_UINT64 size = dbb->dbb_page_size;
 
@@ -802,7 +800,7 @@ bool PIO_write(jrd_file* file, BufferDesc* bdb, Ods::pag* page, ISC_STATUS* stat
 		return unix_error("write", file, isc_io_write_err, status_vector);
 
 	Database* dbb = bdb->bdb_dbb;
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
+	PioCheckout dcoHolder(dbb);
 
 	const SLONG size = dbb->dbb_page_size;
 

src/jrd/os/win32/winnt.cpp

@@ -105,6 +105,29 @@ private:
 using namespace Jrd;
 using namespace Firebird;
 
+namespace {
+
+#ifdef SUPERSERVER
+
+typedef Database::Checkout PioCheckout;
+
+#else
+
+class PioCheckout
+{
+public:
+	PioCheckout(Database*) {}
+	~PioCheckout() {}
+
+private:
+	PioCheckout(const PioCheckout&);
+	PioCheckout& operator=(const PioCheckout&);
+};
+
+#endif
+
+};
+
 #ifdef TEXT
 #undef TEXT
 #endif
@@ -300,7 +323,7 @@ void PIO_extend(Database* dbb, jrd_file* main_file, const ULONG extPages, const
 	if (!main_file->fil_ext_lock)
 		return;
 
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
+	PioCheckout dcoHolder(dbb);
 	FileExtendLockGuard extLock(main_file->fil_ext_lock, true);
 
 	ULONG leftPages = extPages;
@@ -344,7 +367,7 @@ void PIO_flush(Database* dbb, jrd_file* main_file)
  *	Flush the operating system cache back to good, solid oxide.
  *
  **************************************/
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
+	PioCheckout dcoHolder(dbb);
 	for (jrd_file* file = main_file; file; file = file->fil_next)
 	{
 		FlushFileBuffers(file->fil_desc);
@@ -495,7 +518,7 @@ USHORT PIO_init_data(Database* dbb, jrd_file* main_file, ISC_STATUS* status_vect
 	const char* const zero_buff = zeros().getBuffer();
 	const size_t zero_buff_size = zeros().getSize();
 
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
+	PioCheckout dcoHolder(dbb);
 	FileExtendLockGuard extLock(main_file->fil_ext_lock, false);
 
 	// Fake buffer, used in seek_file. Page space ID doesn't matter there
@@ -624,7 +647,7 @@ bool PIO_read(jrd_file* file, BufferDesc* bdb, Ods::pag* page, ISC_STATUS* statu
 	Database* const dbb = bdb->bdb_dbb;
 	const DWORD size = dbb->dbb_page_size;
 
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
+	PioCheckout dcoHolder(dbb);
 	FileExtendLockGuard extLock(file->fil_ext_lock, false);
 
 	OVERLAPPED overlapped, *overlapped_ptr;
@@ -695,7 +718,7 @@ bool PIO_read_ahead(Database*		dbb,
  **************************************/
 	OVERLAPPED overlapped, *overlapped_ptr;
 
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
+	PioCheckout dcoHolder(dbb);
 
 	// If an I/O status block was passed the caller wants to queue an asynchronous I/O.
 
@@ -783,7 +806,7 @@ bool PIO_status(Database* dbb, phys_io_blk* piob, ISC_STATUS* status_vector)
  *	Check the status of an asynchronous I/O.
  *
  **************************************/
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
+	PioCheckout dcoHolder(dbb);
 
 	if (!(piob->piob_flags & PIOB_success))
 	{
@@ -826,7 +849,7 @@ bool PIO_write(jrd_file* file, BufferDesc* bdb, Ods::pag* page, ISC_STATUS* stat
 	Database* const dbb = bdb->bdb_dbb;
 	const DWORD size = dbb->dbb_page_size;
 
-	Database::CheckoutIfNotInAst dcoHolder(dbb);
+	PioCheckout dcoHolder(dbb);
 	FileExtendLockGuard extLock(file->fil_ext_lock, false);
 
 	file = seek_file(file, bdb, status_vector, &overlapped, &overlapped_ptr);