Merges lstat_sync() and filephy() in Windows reduce syscalls.

TODO

@@ -13,12 +13,6 @@ get misinterpreted.
 
 * Shall CreateFileW use FILE_SHARE_DELETE ?
 
-* Merge lstat_sync() and filephy() ? This could save one CreateFileW()
-but it's not clear how it will behave with ReparsePoint, like dedup files.
-lsync_stat opens with BACKUP_SEMANTICS/REPARSE_POINT then instead filephy()
-opens with 0.
-See merge_lstat_sync_and_filephy.diff in contrib/
-
 - Minor
 
 * Don't insert new files if they are too recent and opened by other

cmdline/mingw.c

@@ -690,7 +690,56 @@ int windows_rmdir(const char* file)
 	return 0;
 }
 
-int lstat_sync(const char* file, struct windows_stat* st)
+static BOOL GetFilePhysicalOffset(HANDLE h, uint64_t* physical)
+{
+	STARTING_VCN_INPUT_BUFFER svib;
+	unsigned char rpb_buffer[sizeof(RETRIEVAL_POINTERS_BUFFER)];
+	RETRIEVAL_POINTERS_BUFFER* rpb = (RETRIEVAL_POINTERS_BUFFER*)&rpb_buffer;
+	BOOL ret;
+	DWORD n;
+
+	/* in Wine FSCTL_GET_RETRIVIAL_POINTERS is not supported */
+	if (is_wine) {
+		*physical = FILEPHY_UNREPORTED_OFFSET;
+		return TRUE;
+	}
+
+	/* set the output variable, just to be safe */
+	rpb->ExtentCount = 0;
+
+	/* read the physical address */
+	svib.StartingVcn.QuadPart = 0;
+	ret = DeviceIoControl(h, FSCTL_GET_RETRIEVAL_POINTERS, &svib, sizeof(svib), rpb_buffer, sizeof(rpb_buffer), &n, 0);
+	if (!ret) {
+		DWORD error = GetLastError();
+		if (error == ERROR_MORE_DATA) {
+			/* we ignore ERROR_MODE_DATA because we are interested only at the first entry */
+			/* and this is the expected error if the files has more entries */
+		} else if (error == ERROR_HANDLE_EOF) {
+			/* if the file is small, it can be stored in the Master File Table (MFT) */
+			/* and then it doesn't have a physical address */
+			/* In such case we report a specific fake address, to report this special condition */
+			/* that it's different from the 0 offset reported by the underline file system */
+			*physical = FILEPHY_WITHOUT_OFFSET;
+			return TRUE;
+		} else if (error == ERROR_NOT_SUPPORTED) {
+			/* for disks shared on network this operation is not supported */
+			*physical = FILEPHY_UNREPORTED_OFFSET;
+			return TRUE;
+		} else {
+			return FALSE;
+		}
+	}
+
+	if (rpb->ExtentCount < 1)
+		*physical = FILEPHY_UNREPORTED_OFFSET;
+	else
+		*physical = rpb->Extents[0].Lcn.QuadPart + FILEPHY_REAL_OFFSET;
+
+	return TRUE;
+}
+
+int lstat_sync(const char* file, struct windows_stat* st, uint64_t* physical)
 {
 	BY_HANDLE_FILE_INFORMATION info;
 	FILE_ATTRIBUTE_TAG_INFO tag;
@@ -722,6 +771,16 @@ int lstat_sync(const char* file, struct windows_stat* st)
 		return -1;
 	}
 
+	/* read the physical offset, only if a pointer is provided */
+	if (physical != 0) {
+		if (!GetFilePhysicalOffset(h, physical)) {
+			DWORD error = GetLastError();
+			CloseHandle(h);
+			windows_errno(error);
+			return -1;
+		}
+	}
+
 	if (!CloseHandle(h)) {
 		windows_errno(GetLastError());
 		return -1;
@@ -1348,55 +1407,6 @@ int devuuid(uint64_t device, char* uuid, size_t uuid_size)
 	return 0;
 }
 
-static BOOL GetFilePhysicalOffset(HANDLE h, uint64_t* physical)
-{
-	STARTING_VCN_INPUT_BUFFER svib;
-	unsigned char rpb_buffer[sizeof(RETRIEVAL_POINTERS_BUFFER)];
-	RETRIEVAL_POINTERS_BUFFER* rpb = (RETRIEVAL_POINTERS_BUFFER*)&rpb_buffer;
-	BOOL ret;
-	DWORD n;
-
-	/* in Wine FSCTL_GET_RETRIVIAL_POINTERS is not supported */
-	if (is_wine) {
-		*physical = FILEPHY_UNREPORTED_OFFSET;
-		return TRUE;
-	}
-
-	/* set the output variable, just to be safe */
-	rpb->ExtentCount = 0;
-
-	/* read the physical address */
-	svib.StartingVcn.QuadPart = 0;
-	ret = DeviceIoControl(h, FSCTL_GET_RETRIEVAL_POINTERS, &svib, sizeof(svib), rpb_buffer, sizeof(rpb_buffer), &n, 0);
-	if (!ret) {
-		DWORD error = GetLastError();
-		if (error == ERROR_MORE_DATA) {
-			/* we ignore ERROR_MODE_DATA because we are interested only at the first entry */
-			/* and this is the expected error if the files has more entries */
-		} else if (error == ERROR_HANDLE_EOF) {
-			/* if the file is small, it can be stored in the Master File Table (MFT) */
-			/* and then it doesn't have a physical address */
-			/* In such case we report a specific fake address, to report this special condition */
-			/* that it's different from the 0 offset reported by the underline file system */
-			*physical = FILEPHY_WITHOUT_OFFSET;
-			return TRUE;
-		} else if (error == ERROR_NOT_SUPPORTED) {
-			/* for disks shared on network this operation is not supported */
-			*physical = FILEPHY_UNREPORTED_OFFSET;
-			return TRUE;
-		} else {
-			return FALSE;
-		}
-	}
-
-	if (rpb->ExtentCount < 1)
-		*physical = FILEPHY_UNREPORTED_OFFSET;
-	else
-		*physical = rpb->Extents[0].Lcn.QuadPart + FILEPHY_REAL_OFFSET;
-
-	return TRUE;
-}
-
 int filephy(const char* file, uint64_t size, uint64_t* physical)
 {
 	HANDLE h;

cmdline/mingw.h

@@ -185,7 +185,8 @@ int windows_rmdir(const char* file);
 /**
  * Like the C lstat(), but with some limitations.
  *
- * This call fills all the st_* fields of the stat struct.
+ * This call fills all the st_* fields of the stat struct,
+ * and if provided the pointer, also the physical offset.
  *
  * It doesn't work for all kinds of files and directories.
  * You must call it only for regular files.
@@ -194,7 +195,7 @@ int windows_rmdir(const char* file);
  * Note that instead lstat() works for all the files.
  */
 #define HAVE_LSTAT_SYNC 1
-int lstat_sync(const char* file, struct windows_stat* st);
+int lstat_sync(const char* file, struct windows_stat* st, uint64_t* physical);
 
 /**
  * Like the C ftruncate().

cmdline/scan.c

@@ -295,8 +295,10 @@ static void scan_file_delayed_insert(struct snapraid_scan* scan, struct snapraid
 	struct snapraid_state* state = scan->state;
 	struct snapraid_disk* disk = scan->disk;
 
-	/* if we sort for physical offsets we have to read them for the new files */
-	if (state->opt.force_order == SORT_PHYSICAL) {
+	/* if we sort for physical offsets we have to read them for new files */
+	if (state->opt.force_order == SORT_PHYSICAL
+		&& file->physical == FILEPHY_UNREAD_OFFSET
+	) {
 		char path_next[PATH_MAX];
 
 		pathprint(path_next, sizeof(path_next), "%s%s", disk->dir, file->sub);
@@ -318,10 +320,13 @@ static void scan_file_delayed_insert(struct snapraid_scan* scan, struct snapraid
  * This is needed by Windows as the normal way to list directories may report not
  * updated info. Only the GetFileInformationByHandle() func, called file-by-file,
  * relly ensures to return synced info.
+ *
+ * If this happens, we read also the physical offset, to avoid to read it later.
  */
-static void scan_file_refresh(struct snapraid_scan* scan, const char* sub, struct stat* st)
+static void scan_file_refresh(struct snapraid_scan* scan, const char* sub, struct stat* st, uint64_t* physical)
 {
 #if HAVE_LSTAT_SYNC
+	struct snapraid_state* state = scan->state;
 	struct snapraid_disk* disk = scan->disk;
 
 	/* if the st_sync is not set, ensure to get synced info */
@@ -331,7 +336,16 @@ static void scan_file_refresh(struct snapraid_scan* scan, const char* sub, struc
 
 		pathprint(path_next, sizeof(path_next), "%s%s", disk->dir, sub);
 
-		if (lstat_sync(path_next, &synced_st) != 0) {
+		/* if we sort for physical offsets we have to read them for new files */
+		if (state->opt.force_order == SORT_PHYSICAL
+			&& *physical == FILEPHY_UNREAD_OFFSET
+		) {
+			/* do nothing, leave the pointer to read the physical offset */
+		} else {
+			physical = 0; /* set the pointer to 0 to read nothing */
+		}
+
+		if (lstat_sync(path_next, &synced_st, physical) != 0) {
 			/* LCOV_EXCL_START */
 			fprintf(stderr, "Error in stat file '%s'. %s.\n", path_next, strerror(errno));
 			exit(EXIT_FAILURE);
@@ -809,7 +823,7 @@ static void scan_file(struct snapraid_scan* scan, int output, const char* sub, s
 	/* refresh the info, to ensure that they are synced, */
 	/* not that we refresh only the info of the new or modified files */
 	/* because this is slow operation */
-	scan_file_refresh(scan, sub, st);
+	scan_file_refresh(scan, sub, st, &physical);
 
 	/* do a safety check to ensure that the common ext4 case of zeroing */
 	/* the size of a file after a crash doesn't propagate to the backup */
@@ -1210,7 +1224,7 @@ static int scan_dir(struct snapraid_scan* scan, int output, const char* dir, con
 				/* if the st_ino field is missing, takes care to fill it using the extended lstat() */
 				/* this can happen only in Windows */
 				if (st->st_ino == 0) {
-					if (lstat_sync(path_next, st) != 0) {
+					if (lstat_sync(path_next, st, 0) != 0) {
 						/* LCOV_EXCL_START */
 						fprintf(stderr, "Error in stat file '%s'. %s.\n", path_next, strerror(errno));
 						exit(EXIT_FAILURE);