Add test of large fragmented free lists

Add a test which gives the server a transaction with a free list block
that contains blknos that each dirty an individiaul btree blocks in the
global data free extent btree.

Signed-off-by: Zach Brown <zab@versity.com>

tests/Makefile

@@ -10,7 +10,8 @@ BIN := src/createmany			\
 	src/bulk_create_paths		\
 	src/stage_tmpfile		\
 	src/find_xattrs			\
-	src/create_xattr_loop
+	src/create_xattr_loop		\
+	src/fragmented_data_extents
 
 DEPS := $(wildcard src/*.d)
 

tests/golden/large-fragmented-free

@@ -0,0 +1,3 @@
+== creating fragmented extents
+== unlink file with moved extents to free extents per block
+== cleanup

tests/sequence

@@ -9,6 +9,7 @@ fallocate.sh
 setattr_more.sh
 offline-extent-waiting.sh
 move-blocks.sh
+large-fragmented-free.sh
 enospc.sh
 srch-basic-functionality.sh
 simple-xattr-unit.sh

tests/src/fragmented_data_extents.c

@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2021 Versity Software, Inc.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+/*
+ * This creates fragmented data extents.
+ *
+ * A file is created that has alternating free and allocated extents.
+ * This also results in the global allocator having the matching
+ * fragmented free extent pattern.  While that file is being created,
+ * occasionally an allocated extent is moved to another file.   This
+ * results in a file that has fragmented extents at a given stride that
+ * can be deleted to create free data extents with a given stride.
+ *
+ * We don't have hole punching so to do this quickly we use a goofy
+ * combination of fallocate, truncate, and our move_blocks ioctl.
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <linux/types.h>
+#include <assert.h>
+
+#include "ioctl.h"
+
+#define BLOCK_SIZE 4096
+
+int main(int argc, char **argv)
+{
+	struct scoutfs_ioctl_move_blocks mb = {0,};
+	unsigned long long freed_extents;
+	unsigned long long move_stride;
+	unsigned long long i;
+	int alloc_fd;
+	int trunc_fd;
+	off_t off;
+	int ret;
+
+	if (argc != 5) {
+		printf("%s <freed_extents> <move_stride> <alloc_file> <trunc_file>\n", argv[0]);
+		return 1;
+	}
+
+	freed_extents = strtoull(argv[1], NULL, 0);
+	move_stride = strtoull(argv[2], NULL, 0);
+
+	alloc_fd = open(argv[3], O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
+	if (alloc_fd == -1) {
+		fprintf(stderr, "error opening %s: %d (%s)\n", argv[3], errno, strerror(errno));
+		exit(1);
+	}
+
+	trunc_fd = open(argv[4], O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
+	if (trunc_fd == -1) {
+		fprintf(stderr, "error opening %s: %d (%s)\n", argv[4], errno, strerror(errno));
+		exit(1);
+	}
+
+	for (i = 0, off = 0; i < freed_extents; i++, off += BLOCK_SIZE * 2) {
+
+		ret = fallocate(alloc_fd, 0, off, BLOCK_SIZE * 2);
+		if (ret < 0) {
+			fprintf(stderr, "fallocate at off %llu error: %d (%s)\n",
+				(unsigned long long)off, errno, strerror(errno));
+			exit(1);
+		}
+
+		ret = ftruncate(alloc_fd, off + BLOCK_SIZE);
+		if (ret < 0) {
+			fprintf(stderr, "truncate to off %llu error: %d (%s)\n",
+				(unsigned long long)off + BLOCK_SIZE, errno, strerror(errno));
+			exit(1);
+		}
+
+		if ((i % move_stride) == 0) {
+			mb.from_fd = alloc_fd;
+			mb.from_off = off;
+			mb.len = BLOCK_SIZE;
+			mb.to_off = i * BLOCK_SIZE;
+
+			ret = ioctl(trunc_fd, SCOUTFS_IOC_MOVE_BLOCKS, &mb);
+			if (ret < 0) {
+				fprintf(stderr, "move from off %llu error: %d (%s)\n",
+					(unsigned long long)off,
+					errno, strerror(errno));
+			}
+		}
+	}
+
+	if (alloc_fd > -1)
+		close(alloc_fd);
+	if (trunc_fd > -1)
+		close(trunc_fd);
+
+	return 0;
+}

tests/tests/large-fragmented-free.sh

@@ -0,0 +1,22 @@
+#
+# Make sure the server can handle a transaction with a data_freed whose
+# blocks all hit different btree blocks in the main free list.  It
+# probably has to be merged in multiple commits.
+#
+
+t_require_commands fragmented_data_extents
+
+EXTENTS_PER_BTREE_BLOCK=600
+EXTENTS_PER_LIST_BLOCK=8192
+FREED_EXTENTS=$((EXTENTS_PER_BTREE_BLOCK * EXTENTS_PER_LIST_BLOCK))
+
+echo "== creating fragmented extents"
+fragmented_data_extents $FREED_EXTENTS $EXTENTS_PER_BTREE_BLOCK "$T_D0/alloc" "$T_D0/move"
+
+echo "== unlink file with moved extents to free extents per block"
+rm -f "$T_D0/move"
+
+echo "== cleanup"
+rm -f "$T_D0/alloc"
+
+t_pass