Front ported support for fallocate() call on Linux.

Front ported improvement CORE-4443 : Use fast file grow on those Linux systems which supports it

configure.ac

@@ -690,6 +690,7 @@ AC_CHECK_HEADERS(poll.h)
 AC_CHECK_HEADERS(langinfo.h)
 AC_CHECK_HEADERS(iconv.h)
 AC_CHECK_HEADERS(libio.h)
+AC_CHECK_HEADERS(linux/falloc.h)
 
 dnl check for ICU presence
 AC_CHECK_HEADER(unicode/ucnv.h,,AC_MSG_ERROR(ICU support not found - please install development ICU package))

src/jrd/os/pio.h

@@ -94,6 +94,7 @@ const USHORT FIL_force_write		= 1;
 const USHORT FIL_no_fs_cache		= 2;	// not using file system cache
 const USHORT FIL_readonly			= 4;	// file opened in readonly mode
 const USHORT FIL_sh_write			= 8;	// file opened in shared write mode
+const USHORT FIL_no_fast_extend		= 16;	// file not supports fast extending
 
 // Physical IO trace events
 

src/jrd/os/posix/unix.cpp

@@ -45,6 +45,9 @@
 #ifdef HAVE_AIO_H
 #include <aio.h>
 #endif
+#ifdef HAVE_LINUX_FALLOC_H
+#include <linux/falloc.h>
+#endif
 
 #include "../jrd/jrd.h"
 #include "../jrd/os/pio.h"
@@ -291,7 +294,7 @@ bool PIO_expand(const TEXT* file_name, USHORT file_length, TEXT* expanded_name,
 }
 
 
-void PIO_extend(Database* dbb, jrd_file* /*main_file*/, const ULONG /*extPages*/, const USHORT /*pageSize*/)
+void PIO_extend(Database* dbb, jrd_file* main_file, const ULONG extPages, const USHORT pageSize)
 {
 /**************************************
  *
@@ -303,6 +306,56 @@ void PIO_extend(Database* dbb, jrd_file* /*main_file*/, const ULONG /*extPages*/
  *	Extend file by extPages pages of pageSize size.
  *
  **************************************/
+
+#ifdef HAVE_LINUX_FALLOC_H
+	ULONG leftPages = extPages;
+	for (jrd_file* file = main_file; file && leftPages; file = file->fil_next)
+	{
+		const ULONG filePages = PIO_get_number_of_pages(file, pageSize);
+		const ULONG fileMaxPages = (file->fil_max_page == MAX_ULONG) ?
+									MAX_ULONG : file->fil_max_page - file->fil_min_page + 1;
+		if (filePages < fileMaxPages)
+		{
+			if (file->fil_flags & FIL_no_fast_extend) 
+				return;
+
+			const ULONG extendBy = MIN(fileMaxPages - filePages + file->fil_fudge, leftPages);
+
+			int r;
+			for (r = 0; r < IO_RETRY; r++)
+			{
+				int err = fallocate(file->fil_desc, 0, filePages * pageSize, extendBy * pageSize);
+				if (err == 0)
+					break;
+
+				err = errno;
+				if (SYSCALL_INTERRUPTED(err))
+					continue;
+
+				if (err == EOPNOTSUPP || err == ENOSYS)
+					file->fil_flags |= FIL_no_fast_extend;
+				else
+					unix_error("fallocate", file, isc_io_write_err);
+				return;
+			}
+
+			if (r == IO_RETRY)
+			{
+#ifdef DEV_BUILD
+				fprintf(stderr, "PIO_extend: retry count exceeded\n");
+				fflush(stderr);
+#endif
+				unix_error("fallocate_retry", file, isc_io_write_err);
+				return;
+			}
+
+			leftPages -= extendBy;
+		}
+	}
+#else
+	main_file->fil_flags |= FIL_no_fast_extend;
+#endif // HAVE_LINUX_FALLOC_H
+
 	// not implemented
 	return;
 }

src/jrd/pag.cpp

@@ -640,7 +640,7 @@ PAG PAG_allocate(thread_db* tdbb, WIN* window)
 								// At this point we ensure database has at least "initialized" pages
 								// allocated. To avoid file growth by few pages when all this space
 								// will be used, extend file up to initialized + next_init_pages now
-								pageSpace->extend(tdbb, initialized + next_init_pages);
+								pageSpace->extend(tdbb, initialized + next_init_pages, false);
 							}
 
 							break;	// Found a page and successfully fake-ed it
@@ -2039,7 +2039,7 @@ ULONG PageSpace::lastUsedPage(const Database* dbb)
 	return pgSpace->lastUsedPage();
 }
 
-bool PageSpace::extend(thread_db* tdbb, const ULONG pageNum)
+bool PageSpace::extend(thread_db* tdbb, const ULONG pageNum, const bool forceSize)
 {
 /**************************************
  *
@@ -2051,12 +2051,16 @@ bool PageSpace::extend(thread_db* tdbb, const ULONG pageNum)
  *	If "DatabaseGrowthIncrement" is less than MIN_EXTEND_BYTES then don't
  *	extend file(s)
  *
+ *  If forceSize is true, extend file up to pageNum pages (despite of value
+ *  of "DatabaseGrowthIncrement") and don't make attempts to extend by less
+ *	pages.
+ *
  **************************************/
 	fb_assert(dbb == tdbb->getDatabase());
 
 	const int MAX_EXTEND_BYTES = dbb->dbb_config->getDatabaseGrowthIncrement();
 
-	if (pageNum < maxPageNumber || MAX_EXTEND_BYTES < MIN_EXTEND_BYTES)
+	if (pageNum < maxPageNumber || MAX_EXTEND_BYTES < MIN_EXTEND_BYTES && !forceSize)
 		return true;
 
 	if (pageNum >= maxAlloc())
@@ -2071,6 +2075,7 @@ bool PageSpace::extend(thread_db* tdbb, const ULONG pageNum)
 
 		while (true)
 		{
+			const ULONG oldMaxPageNumber = maxPageNumber;
 			try
 			{
 				PIO_extend(dbb, file, extPages, dbb->dbb_page_size);
@@ -2078,10 +2083,16 @@ bool PageSpace::extend(thread_db* tdbb, const ULONG pageNum)
 			}
 			catch (const status_exception&)
 			{
-				if (extPages > reqPages)
+				if (extPages > reqPages && !forceSize)
 				{
-					extPages = MAX(reqPages, extPages / 2);
 					fb_utils::init_status(tdbb->tdbb_status_vector);
+
+					// if file was extended, return, else try to extend by less pages
+
+					if (oldMaxPageNumber < maxAlloc())
+						return true;
+
+					extPages = MAX(reqPages, extPages / 2);
 				}
 				else
 				{

src/jrd/pag.h

@@ -120,7 +120,7 @@ public:
 	static ULONG lastUsedPage(const Database* dbb);
 
 	// extend page space
-	bool extend(thread_db*, const ULONG);
+	bool extend(thread_db*, const ULONG, const bool);
 
 	// get SCN's page number
 	ULONG getSCNPageNum(ULONG sequence);