path: root/fs/btrfs/tests/extent-map-tests.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2017 Oracle.  All rights reserved.
 */

#include <linux/types.h>
#include "btrfs-tests.h"
#include "../ctree.h"
#include "../btrfs_inode.h"
#include "../volumes.h"
#include "../disk-io.h"
#include "../block-group.h"

static int free_extent_map_tree(struct btrfs_inode *inode)
{
	struct extent_map_tree *em_tree = &inode->extent_tree;
	struct extent_map *em;
	struct rb_node *node;
	int ret = 0;

	write_lock(&em_tree->lock);
	while (!RB_EMPTY_ROOT(&em_tree->root)) {
		node = rb_first(&em_tree->root);
		em = rb_entry(node, struct extent_map, rb_node);
		remove_extent_mapping(inode, em);

#ifdef CONFIG_BTRFS_DEBUG
		if (refcount_read(&em->refs) != 1) {
			ret = -EINVAL;
			test_err(
"em leak: em (start %llu len %llu disk_bytenr %llu disk_num_bytes %llu offset %llu) refs %d",
				 em->start, em->len, em->disk_bytenr,
				 em->disk_num_bytes, em->offset,
				 refcount_read(&em->refs));

			refcount_set(&em->refs, 1);
		}
#endif
		free_extent_map(em);
	}
	write_unlock(&em_tree->lock);

	return ret;
}

/*
 * Test scenario:
 *
 * Suppose that no extent map has been loaded into memory yet, there is a file
 * extent [0, 16K), followed by another file extent [16K, 20K), two dio reads
 * are entering btrfs_get_extent() concurrently, t1 is reading [8K, 16K), t2 is
 * reading [0, 8K)
 *
 *     t1                            t2
 *  btrfs_get_extent()              btrfs_get_extent()
 *    -> lookup_extent_mapping()      ->lookup_extent_mapping()
 *    -> add_extent_mapping(0, 16K)
 *    -> return em
 *                                    ->add_extent_mapping(0, 16K)
 *                                    -> #handle -EEXIST
 */
static int test_case_1(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode)
{
	struct extent_map_tree *em_tree = &inode->extent_tree;
	struct extent_map *em;
	u64 start = 0;
	u64 len = SZ_8K;
	int ret;
	int ret2;

	em = alloc_extent_map();
	if (!em) {
		test_std_err(TEST_ALLOC_EXTENT_MAP);
		return -ENOMEM;
	}

	/* Add [0, 16K) */
	em->start = 0;
	em->len = SZ_16K;
	em->disk_bytenr = 0;
	em->disk_num_bytes = SZ_16K;
	em->ram_bytes = SZ_16K;
	write_lock(&em_tree->lock);
	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
	write_unlock(&em_tree->lock);
	if (ret < 0) {
		test_err("cannot add extent range [0, 16K)");
		goto out;
	}
	free_extent_map(em);

	/* Add [16K, 20K) following [0, 16K)  */
	em = alloc_extent_map();
	if (!em) {
		test_std_err(TEST_ALLOC_EXTENT_MAP);
		ret = -ENOMEM;
		goto out;
	}

	em->start = SZ_16K;
	em->len = SZ_4K;
	em->disk_bytenr = SZ_32K; /* avoid merging */
	em->disk_num_bytes = SZ_4K;
	em->ram_bytes = SZ_4K;
	write_lock(&em_tree->lock);
	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
	write_unlock(&em_tree->lock);
	if (ret < 0) {
		test_err("cannot add extent range [16K, 20K)");
		goto out;
	}
	free_extent_map(em);

	em = alloc_extent_map();
	if (!em) {
		test_std_err(TEST_ALLOC_EXTENT_MAP);
		ret = -ENOMEM;
		goto out;
	}

	/* Add [0, 8K), should return [0, 16K) instead. */
	em->start = start;
	em->len = len;
	em->disk_bytenr = start;
	em->disk_num_bytes = len;
	em->ram_bytes = len;
	write_lock(&em_tree->lock);
	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
	write_unlock(&em_tree->lock);
	if (ret) {
		test_err(