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linux-hardened/fs/btrfs/tests/extent-map-tests.c
Liu Bo 07e1ce096d Btrfs: extent_map: use rb_first_cached 
rb_first_cached() trades an extra pointer "leftmost" for doing the
same job as rb_first() but in O(1).

As evict_inode_truncate_pages() removes all extent mapping by always
looking for the first rb entry, it's helpful to use rb_first_cached
instead.

For more details about the optimization see patch "Btrfs: delayed-refs:
use rb_first_cached for href_root".

Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:33 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2017 Oracle. All rights reserved.
*/
#include <linux/types.h>
#include "btrfs-tests.h"
#include "../ctree.h"
static void free_extent_map_tree(struct extent_map_tree *em_tree)
{
struct extent_map *em;
struct rb_node *node;
while (!RB_EMPTY_ROOT(&em_tree->map.rb_root)) {
node = rb_first_cached(&em_tree->map);
em = rb_entry(node, struct extent_map, rb_node);
remove_extent_mapping(em_tree, em);
#ifdef CONFIG_BTRFS_DEBUG
if (refcount_read(&em->refs) != 1) {
test_err(
"em leak: em (start 0x%llx len 0x%llx block_start 0x%llx block_len 0x%llx) refs %d",
em->start, em->len, em->block_start,
em->block_len, refcount_read(&em->refs));
refcount_set(&em->refs, 1);
}
#endif
free_extent_map(em);
}
}
/*
* 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 void test_case_1(struct btrfs_fs_info *fs_info,
struct extent_map_tree *em_tree)
{
struct extent_map *em;
u64 start = 0;
u64 len = SZ_8K;
int ret;
em = alloc_extent_map();
if (!em)
/* Skip the test on error. */
return;
/* Add [0, 16K) */
em->start = 0;
em->len = SZ_16K;
em->block_start = 0;
em->block_len = SZ_16K;
ret = add_extent_mapping(em_tree, em, 0);
ASSERT(ret == 0);
free_extent_map(em);
/* Add [16K, 20K) following [0, 16K) */
em = alloc_extent_map();
if (!em)
goto out;
em->start = SZ_16K;
em->len = SZ_4K;
em->block_start = SZ_32K; /* avoid merging */
em->block_len = SZ_4K;
ret = add_extent_mapping(em_tree, em, 0);
ASSERT(ret == 0);
free_extent_map(em);
em = alloc_extent_map();
if (!em)
goto out;
/* Add [0, 8K), should return [0, 16K) instead. */
em->start = start;
em->len = len;
em->block_start = start;
em->block_len = len;
ret = btrfs_add_extent_mapping(fs_info, em_tree, &em, em->start, em->len);
if (ret)
test_err("case1 [%llu %llu]: ret %d", start, start + len, ret);
if (em &&
(em->start != 0 || extent_map_end(em) != SZ_16K ||
em->block_start != 0 || em->block_len != SZ_16K))
test_err(
"case1 [%llu %llu]: ret %d return a wrong em (start %llu len %llu block_start %llu block_len %llu",
start, start + len, ret, em->start, em->len,
em->block_start, em->block_len);
free_extent_map(em);
out:
/* free memory */
free_extent_map_tree(em_tree);
}
/*
* Test scenario:
*
* Reading the inline ending up with EEXIST, ie. read an inline
* extent and discard page cache and read it again.
*/
static void test_case_2(struct btrfs_fs_info *fs_info,
struct extent_map_tree *em_tree)
{
struct extent_map *em;
int ret;
em = alloc_extent_map();
if (!em)
/* Skip the test on error. */
return;
/* Add [0, 1K) */
em->start = 0;
em->len = SZ_1K;
em->block_start = EXTENT_MAP_INLINE;
em->block_len = (u64)-1;
ret = add_extent_mapping(em_tree, em, 0);
ASSERT(ret == 0);
free_extent_map(em);
/* Add [4K, 4K) following [0, 1K) */
em = alloc_extent_map();
if (!em)
goto out;
em->start = SZ_4K;
em->len = SZ_4K;
em->block_start = SZ_4K;
em->block_len = SZ_4K;
ret = add_extent_mapping(em_tree, em, 0);
ASSERT(ret == 0);
free_extent_map(em);
em = alloc_extent_map();
if (!em)
goto out;
/* Add [0, 1K) */
em->start = 0;
em->len = SZ_1K;
em->block_start = EXTENT_MAP_INLINE;
em->block_len = (u64)-1;
ret = btrfs_add_extent_mapping(fs_info, em_tree, &em, em->start, em->len);
if (ret)
test_err("case2 [0 1K]: ret %d", ret);
if (em &&
(em->start != 0 || extent_map_end(em) != SZ_1K ||
em->block_start != EXTENT_MAP_INLINE || em->block_len != (u64)-1))
test_err(
"case2 [0 1K]: ret %d return a wrong em (start %llu len %llu block_start %llu block_len %llu",
ret, em->start, em->len, em->block_start,
em->block_len);
free_extent_map(em);
out:
/* free memory */
free_extent_map_tree(em_tree);
}
static void __test_case_3(struct btrfs_fs_info *fs_info,
struct extent_map_tree *em_tree, u64 start)
{
struct extent_map *em;
u64 len = SZ_4K;
int ret;
em = alloc_extent_map();
if (!em)
/* Skip this test on error. */
return;
/* Add [4K, 8K) */
em->start = SZ_4K;
em->len = SZ_4K;
em->block_start = SZ_4K;
em->block_len = SZ_4K;
ret = add_extent_mapping(em_tree, em, 0);
ASSERT(ret == 0);
free_extent_map(em);
em = alloc_extent_map();
if (!em)
goto out;
/* Add [0, 16K) */
em->start = 0;
em->len = SZ_16K;
em->block_start = 0;
em->block_len = SZ_16K;
ret = btrfs_add_extent_mapping(fs_info, em_tree, &em, start, len);
if (ret)
test_err("case3 [0x%llx 0x%llx): ret %d",
start, start + len, ret);
/*
* Since bytes within em are contiguous, em->block_start is identical to
* em->start.
*/
if (em &&
(start < em->start || start + len > extent_map_end(em) ||
em->start != em->block_start || em->len != em->block_len))
test_err(
"case3 [0x%llx 0x%llx): ret %d em (start 0x%llx len 0x%llx block_start 0x%llx block_len 0x%llx)",
start, start + len, ret, em->start, em->len,
em->block_start, em->block_len);
free_extent_map(em);
out:
/* free memory */
free_extent_map_tree(em_tree);
}
/*
* Test scenario:
*
* Suppose that no extent map has been loaded into memory yet.
* There is a file extent [0, 16K), two jobs are running concurrently
* against it, t1 is buffered writing to [4K, 8K) and t2 is doing dio
* read from [0, 4K) or [8K, 12K) or [12K, 16K).
*
* t1 goes ahead of t2 and adds em [4K, 8K) into tree.
*
* t1 t2
* cow_file_range() btrfs_get_extent()
* -> lookup_extent_mapping()
* -> add_extent_mapping()
* -> add_extent_mapping()
*/
static void test_case_3(struct btrfs_fs_info *fs_info,
struct extent_map_tree *em_tree)
{
__test_case_3(fs_info, em_tree, 0);
__test_case_3(fs_info, em_tree, SZ_8K);
__test_case_3(fs_info, em_tree, (12 * 1024ULL));
}
static void __test_case_4(struct btrfs_fs_info *fs_info,
struct extent_map_tree *em_tree, u64 start)
{
struct extent_map *em;
u64 len = SZ_4K;
int ret;
em = alloc_extent_map();
if (!em)
/* Skip this test on error. */
return;
/* Add [0K, 8K) */
em->start = 0;
em->len = SZ_8K;
em->block_start = 0;
em->block_len = SZ_8K;
ret = add_extent_mapping(em_tree, em, 0);
ASSERT(ret == 0);
free_extent_map(em);
em = alloc_extent_map();
if (!em)
goto out;
/* Add [8K, 24K) */
em->start = SZ_8K;
em->len = 24 * 1024ULL;
em->block_start = SZ_16K; /* avoid merging */
em->block_len = 24 * 1024ULL;
ret = add_extent_mapping(em_tree, em, 0);
ASSERT(ret == 0);
free_extent_map(em);
em = alloc_extent_map();
if (!em)
goto out;
/* Add [0K, 32K) */
em->start = 0;
em->len = SZ_32K;
em->block_start = 0;
em->block_len = SZ_32K;
ret = btrfs_add_extent_mapping(fs_info, em_tree, &em, start, len);
if (ret)
test_err("case4 [0x%llx 0x%llx): ret %d",
start, len, ret);
if (em &&
(start < em->start || start + len > extent_map_end(em)))
test_err(
"case4 [0x%llx 0x%llx): ret %d, added wrong em (start 0x%llx len 0x%llx block_start 0x%llx block_len 0x%llx)",
start, len, ret, em->start, em->len, em->block_start,
em->block_len);
free_extent_map(em);
out:
/* free memory */
free_extent_map_tree(em_tree);
}
/*
* Test scenario:
*
* Suppose that no extent map has been loaded into memory yet.
* There is a file extent [0, 32K), two jobs are running concurrently
* against it, t1 is doing dio write to [8K, 32K) and t2 is doing dio
* read from [0, 4K) or [4K, 8K).
*
* t1 goes ahead of t2 and splits em [0, 32K) to em [0K, 8K) and [8K 32K).
*
* t1 t2
* btrfs_get_blocks_direct() btrfs_get_blocks_direct()
* -> btrfs_get_extent() -> btrfs_get_extent()
* -> lookup_extent_mapping()
* -> add_extent_mapping() -> lookup_extent_mapping()
* # load [0, 32K)
* -> btrfs_new_extent_direct()
* -> btrfs_drop_extent_cache()
* # split [0, 32K)
* -> add_extent_mapping()
* # add [8K, 32K)
* -> add_extent_mapping()
* # handle -EEXIST when adding
* # [0, 32K)
*/
static void test_case_4(struct btrfs_fs_info *fs_info,
struct extent_map_tree *em_tree)
{
__test_case_4(fs_info, em_tree, 0);
__test_case_4(fs_info, em_tree, SZ_4K);
}
int btrfs_test_extent_map(void)
{
struct btrfs_fs_info *fs_info = NULL;
struct extent_map_tree *em_tree;
test_msg("running extent_map tests");
/*
* Note: the fs_info is not set up completely, we only need
* fs_info::fsid for the tracepoint.
*/
fs_info = btrfs_alloc_dummy_fs_info(PAGE_SIZE, PAGE_SIZE);
if (!fs_info) {
test_msg("Couldn't allocate dummy fs info");
return -ENOMEM;
}
em_tree = kzalloc(sizeof(*em_tree), GFP_KERNEL);
if (!em_tree)
/* Skip the test on error. */
goto out;
extent_map_tree_init(em_tree);
test_case_1(fs_info, em_tree);
test_case_2(fs_info, em_tree);
test_case_3(fs_info, em_tree);
test_case_4(fs_info, em_tree);
kfree(em_tree);
out:
btrfs_free_dummy_fs_info(fs_info);
return 0;
}
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