ext4: add first unit test for ext4_mb_new_blocks_simple in mballoc

Here are prepared work:
1. Include mballoc-test.c to mballoc.c to be able test static function
in mballoc.c.
2. Implement static stub to avoid read IO to disk.
3. Construct fake super_block. Only partial members are set, more members
will be set when more functions are tested.
Then unit test for ext4_mb_new_blocks_simple is added.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230928160407.142069-12-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Kemeng Shi 2023-09-29 00:04:06 +08:00 committed by Theodore Ts'o
parent bdefd689b7
commit 7c9fa399a3
2 changed files with 329 additions and 0 deletions

325
fs/ext4/mballoc-test.c Normal file
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@ -0,0 +1,325 @@
// SPDX-License-Identifier: GPL-2.0
/*
* KUnit test of ext4 multiblocks allocation.
*/
#include <kunit/test.h>
#include <kunit/static_stub.h>
#include "ext4.h"
struct mbt_grp_ctx {
struct buffer_head bitmap_bh;
/* desc and gd_bh are just the place holders for now */
struct ext4_group_desc desc;
struct buffer_head gd_bh;
};
struct mbt_ctx {
struct mbt_grp_ctx *grp_ctx;
};
struct mbt_ext4_super_block {
struct super_block sb;
struct mbt_ctx mbt_ctx;
};
#define MBT_CTX(_sb) (&(container_of((_sb), struct mbt_ext4_super_block, sb)->mbt_ctx))
#define MBT_GRP_CTX(_sb, _group) (&MBT_CTX(_sb)->grp_ctx[_group])
static struct super_block *mbt_ext4_alloc_super_block(void)
{
struct ext4_super_block *es = kzalloc(sizeof(*es), GFP_KERNEL);
struct ext4_sb_info *sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
struct mbt_ext4_super_block *fsb = kzalloc(sizeof(*fsb), GFP_KERNEL);
if (fsb == NULL || sbi == NULL || es == NULL)
goto out;
sbi->s_es = es;
fsb->sb.s_fs_info = sbi;
return &fsb->sb;
out:
kfree(fsb);
kfree(sbi);
kfree(es);
return NULL;
}
static void mbt_ext4_free_super_block(struct super_block *sb)
{
struct mbt_ext4_super_block *fsb =
container_of(sb, struct mbt_ext4_super_block, sb);
struct ext4_sb_info *sbi = EXT4_SB(sb);
kfree(sbi->s_es);
kfree(sbi);
kfree(fsb);
}
struct mbt_ext4_block_layout {
unsigned char blocksize_bits;
unsigned int cluster_bits;
uint32_t blocks_per_group;
ext4_group_t group_count;
uint16_t desc_size;
};
static void mbt_init_sb_layout(struct super_block *sb,
struct mbt_ext4_block_layout *layout)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
sb->s_blocksize = 1UL << layout->blocksize_bits;
sb->s_blocksize_bits = layout->blocksize_bits;
sbi->s_groups_count = layout->group_count;
sbi->s_blocks_per_group = layout->blocks_per_group;
sbi->s_cluster_bits = layout->cluster_bits;
sbi->s_cluster_ratio = 1U << layout->cluster_bits;
sbi->s_clusters_per_group = layout->blocks_per_group >>
layout->cluster_bits;
sbi->s_desc_size = layout->desc_size;
es->s_first_data_block = cpu_to_le32(0);
es->s_blocks_count_lo = cpu_to_le32(layout->blocks_per_group *
layout->group_count);
}
static int mbt_grp_ctx_init(struct super_block *sb,
struct mbt_grp_ctx *grp_ctx)
{
grp_ctx->bitmap_bh.b_data = kzalloc(EXT4_BLOCK_SIZE(sb), GFP_KERNEL);
if (grp_ctx->bitmap_bh.b_data == NULL)
return -ENOMEM;
return 0;
}
static void mbt_grp_ctx_release(struct mbt_grp_ctx *grp_ctx)
{
kfree(grp_ctx->bitmap_bh.b_data);
grp_ctx->bitmap_bh.b_data = NULL;
}
static void mbt_ctx_mark_used(struct super_block *sb, ext4_group_t group,
unsigned int start, unsigned int len)
{
struct mbt_grp_ctx *grp_ctx = MBT_GRP_CTX(sb, group);
mb_set_bits(grp_ctx->bitmap_bh.b_data, start, len);
}
/* called after mbt_init_sb_layout */
static int mbt_ctx_init(struct super_block *sb)
{
struct mbt_ctx *ctx = MBT_CTX(sb);
ext4_group_t i, ngroups = ext4_get_groups_count(sb);
ctx->grp_ctx = kcalloc(ngroups, sizeof(struct mbt_grp_ctx),
GFP_KERNEL);
if (ctx->grp_ctx == NULL)
return -ENOMEM;
for (i = 0; i < ngroups; i++)
if (mbt_grp_ctx_init(sb, &ctx->grp_ctx[i]))
goto out;
/*
* first data block(first cluster in first group) is used by
* metadata, mark it used to avoid to alloc data block at first
* block which will fail ext4_sb_block_valid check.
*/
mb_set_bits(ctx->grp_ctx[0].bitmap_bh.b_data, 0, 1);
return 0;
out:
while (i-- > 0)
mbt_grp_ctx_release(&ctx->grp_ctx[i]);
kfree(ctx->grp_ctx);
return -ENOMEM;
}
static void mbt_ctx_release(struct super_block *sb)
{
struct mbt_ctx *ctx = MBT_CTX(sb);
ext4_group_t i, ngroups = ext4_get_groups_count(sb);
for (i = 0; i < ngroups; i++)
mbt_grp_ctx_release(&ctx->grp_ctx[i]);
kfree(ctx->grp_ctx);
}
static struct buffer_head *
ext4_read_block_bitmap_nowait_stub(struct super_block *sb, ext4_group_t block_group,
bool ignore_locked)
{
struct mbt_grp_ctx *grp_ctx = MBT_GRP_CTX(sb, block_group);
/* paired with brelse from caller of ext4_read_block_bitmap_nowait */
get_bh(&grp_ctx->bitmap_bh);
return &grp_ctx->bitmap_bh;
}
static int ext4_wait_block_bitmap_stub(struct super_block *sb,
ext4_group_t block_group,
struct buffer_head *bh)
{
return 0;
}
static struct ext4_group_desc *
ext4_get_group_desc_stub(struct super_block *sb, ext4_group_t block_group,
struct buffer_head **bh)
{
struct mbt_grp_ctx *grp_ctx = MBT_GRP_CTX(sb, block_group);
if (bh != NULL)
*bh = &grp_ctx->gd_bh;
return &grp_ctx->desc;
}
static int
ext4_mb_mark_context_stub(handle_t *handle, struct super_block *sb, bool state,
ext4_group_t group, ext4_grpblk_t blkoff,
ext4_grpblk_t len, int flags,
ext4_grpblk_t *ret_changed)
{
struct mbt_grp_ctx *grp_ctx = MBT_GRP_CTX(sb, group);
struct buffer_head *bitmap_bh = &grp_ctx->bitmap_bh;
if (state)
mb_set_bits(bitmap_bh->b_data, blkoff, len);
else
mb_clear_bits(bitmap_bh->b_data, blkoff, len);
return 0;
}
#define TEST_BLOCKSIZE_BITS 10
#define TEST_CLUSTER_BITS 3
#define TEST_BLOCKS_PER_GROUP 8192
#define TEST_GROUP_COUNT 4
#define TEST_DESC_SIZE 64
#define TEST_GOAL_GROUP 1
static int mbt_kunit_init(struct kunit *test)
{
struct mbt_ext4_block_layout layout = {
.blocksize_bits = TEST_BLOCKSIZE_BITS,
.cluster_bits = TEST_CLUSTER_BITS,
.blocks_per_group = TEST_BLOCKS_PER_GROUP,
.group_count = TEST_GROUP_COUNT,
.desc_size = TEST_DESC_SIZE,
};
struct super_block *sb;
int ret;
sb = mbt_ext4_alloc_super_block();
if (sb == NULL)
return -ENOMEM;
mbt_init_sb_layout(sb, &layout);
ret = mbt_ctx_init(sb);
if (ret != 0) {
mbt_ext4_free_super_block(sb);
return ret;
}
test->priv = sb;
kunit_activate_static_stub(test,
ext4_read_block_bitmap_nowait,
ext4_read_block_bitmap_nowait_stub);
kunit_activate_static_stub(test,
ext4_wait_block_bitmap,
ext4_wait_block_bitmap_stub);
kunit_activate_static_stub(test,
ext4_get_group_desc,
ext4_get_group_desc_stub);
kunit_activate_static_stub(test,
ext4_mb_mark_context,
ext4_mb_mark_context_stub);
return 0;
}
static void mbt_kunit_exit(struct kunit *test)
{
struct super_block *sb = (struct super_block *)test->priv;
mbt_ctx_release(sb);
mbt_ext4_free_super_block(sb);
}
static void test_new_blocks_simple(struct kunit *test)
{
struct super_block *sb = (struct super_block *)test->priv;
struct inode inode = { .i_sb = sb, };
struct ext4_allocation_request ar;
ext4_group_t i, goal_group = TEST_GOAL_GROUP;
int err = 0;
ext4_fsblk_t found;
struct ext4_sb_info *sbi = EXT4_SB(sb);
ar.inode = &inode;
/* get block at goal */
ar.goal = ext4_group_first_block_no(sb, goal_group);
found = ext4_mb_new_blocks_simple(&ar, &err);
KUNIT_ASSERT_EQ_MSG(test, ar.goal, found,
"failed to alloc block at goal, expected %llu found %llu",
ar.goal, found);
/* get block after goal in goal group */
ar.goal = ext4_group_first_block_no(sb, goal_group);
found = ext4_mb_new_blocks_simple(&ar, &err);
KUNIT_ASSERT_EQ_MSG(test, ar.goal + EXT4_C2B(sbi, 1), found,
"failed to alloc block after goal in goal group, expected %llu found %llu",
ar.goal + 1, found);
/* get block after goal group */
mbt_ctx_mark_used(sb, goal_group, 0, EXT4_CLUSTERS_PER_GROUP(sb));
ar.goal = ext4_group_first_block_no(sb, goal_group);
found = ext4_mb_new_blocks_simple(&ar, &err);
KUNIT_ASSERT_EQ_MSG(test,
ext4_group_first_block_no(sb, goal_group + 1), found,
"failed to alloc block after goal group, expected %llu found %llu",
ext4_group_first_block_no(sb, goal_group + 1), found);
/* get block before goal group */
for (i = goal_group; i < ext4_get_groups_count(sb); i++)
mbt_ctx_mark_used(sb, i, 0, EXT4_CLUSTERS_PER_GROUP(sb));
ar.goal = ext4_group_first_block_no(sb, goal_group);
found = ext4_mb_new_blocks_simple(&ar, &err);
KUNIT_ASSERT_EQ_MSG(test,
ext4_group_first_block_no(sb, 0) + EXT4_C2B(sbi, 1), found,
"failed to alloc block before goal group, expected %llu found %llu",
ext4_group_first_block_no(sb, 0 + EXT4_C2B(sbi, 1)), found);
/* no block available, fail to allocate block */
for (i = 0; i < ext4_get_groups_count(sb); i++)
mbt_ctx_mark_used(sb, i, 0, EXT4_CLUSTERS_PER_GROUP(sb));
ar.goal = ext4_group_first_block_no(sb, goal_group);
found = ext4_mb_new_blocks_simple(&ar, &err);
KUNIT_ASSERT_NE_MSG(test, err, 0,
"unexpectedly get block when no block is available");
}
static struct kunit_case mbt_test_cases[] = {
KUNIT_CASE(test_new_blocks_simple),
{}
};
static struct kunit_suite mbt_test_suite = {
.name = "ext4_mballoc_test",
.init = mbt_kunit_init,
.exit = mbt_kunit_exit,
.test_cases = mbt_test_cases,
};
kunit_test_suites(&mbt_test_suite);
MODULE_LICENSE("GPL");

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@ -6991,3 +6991,7 @@ out_unload:
return error;
}
#ifdef CONFIG_EXT4_KUNIT_TESTS
#include "mballoc-test.c"
#endif