Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx> writes: > 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@xxxxxxxxxxxxxxx> > --- > fs/ext4/mballoc-test.c | 323 +++++++++++++++++++++++++++++++++++++++++ > fs/ext4/mballoc.c | 4 + > 2 files changed, 327 insertions(+) > create mode 100644 fs/ext4/mballoc-test.c > > diff --git a/fs/ext4/mballoc-test.c b/fs/ext4/mballoc-test.c > new file mode 100644 > index 000000000000..184e6cb2070f > --- /dev/null > +++ b/fs/ext4/mballoc-test.c > @@ -0,0 +1,323 @@ > +// 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 mb_grp_ctx { > + struct buffer_head bitmap_bh; > + struct ext4_group_desc desc; > + /* one group descriptor for each group descriptor for simplicity */ > + struct buffer_head gd_bh; > +}; I suppose desc and gd_bh are just the place holders so that ext4_mb_new_blocks_simple() doesn't fail right? Is there any other use of this? Because I don't see we initializing these. > + > +struct mb_ctx { > + struct mb_grp_ctx *grp_ctx; > +}; > + > +struct fake_super_block { > + struct super_block sb; > + struct mb_ctx mb_ctx; > +}; > + > +#define MB_CTX(_sb) (&(container_of((_sb), struct fake_super_block, sb)->mb_ctx)) > +#define MB_GRP_CTX(_sb, _group) (&MB_CTX(_sb)->grp_ctx[_group]) > + > +static struct super_block *alloc_fake_super_block(void) > +{ > + struct ext4_super_block *es = kzalloc(sizeof(*es), GFP_KERNEL); > + struct ext4_sb_info *sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); > + struct fake_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 free_fake_super_block(struct super_block *sb) > +{ > + struct fake_super_block *fsb = container_of(sb, struct fake_super_block, sb); > + struct ext4_sb_info *sbi = EXT4_SB(sb); > + > + kfree(sbi->s_es); > + kfree(sbi); > + kfree(fsb); > +} > + > +struct ext4_block_layout { > + unsigned char blocksize_bits; > + unsigned int cluster_bits; > + unsigned long blocks_per_group; > + ext4_group_t group_count; > + unsigned long desc_size; > +}; > + > +static void init_sb_layout(struct super_block *sb, > + struct 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 mb_grp_ctx_init(struct super_block *sb, > + struct mb_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; > + > + get_bh(&grp_ctx->bitmap_bh); > + get_bh(&grp_ctx->gd_bh); > + return 0; > +} > + > +static void mb_grp_ctx_release(struct mb_grp_ctx *grp_ctx) > +{ > + kfree(grp_ctx->bitmap_bh.b_data); > + grp_ctx->bitmap_bh.b_data = NULL; No brelse() here? > +} > + > +static void mb_ctx_mark_used(struct super_block *sb, ext4_group_t group, > + unsigned int start, unsigned int len) > +{ > + struct mb_grp_ctx *grp_ctx = MB_GRP_CTX(sb, group); > + > + mb_set_bits(grp_ctx->bitmap_bh.b_data, start, len); > +} > + > +/* called after init_sb_layout */ > +static int mb_ctx_init(struct super_block *sb) > +{ > + struct mb_ctx *ctx = MB_CTX(sb); > + ext4_group_t i, ngroups = ext4_get_groups_count(sb); > + > + ctx->grp_ctx = kcalloc(ngroups, sizeof(struct mb_grp_ctx), > + GFP_KERNEL); > + if (ctx->grp_ctx == NULL) > + return -ENOMEM; > + > + for (i = 0; i < ngroups; i++) > + if (mb_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) > + mb_grp_ctx_release(&ctx->grp_ctx[i]); > + kfree(ctx->grp_ctx); > + return -ENOMEM; > +} > + > +static void mb_ctx_release(struct super_block *sb) > +{ > + struct mb_ctx *ctx = MB_CTX(sb); > + ext4_group_t i, ngroups = ext4_get_groups_count(sb); > + > + for (i = 0; i < ngroups; i++) > + mb_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 mb_grp_ctx *grp_ctx = MB_GRP_CTX(sb, block_group); > + > + get_bh(&grp_ctx->bitmap_bh); I don't know how will you call brelse() for this? It should be ok anyways since it's not a real buffer_head. But may be it will be good to add a comment about it. > + 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 mb_grp_ctx *grp_ctx = MB_GRP_CTX(sb, block_group); > + > + if (bh != NULL) > + *bh = &grp_ctx->gd_bh; > + > + return &grp_ctx->desc; > +} > + > +static int ext4_mb_mark_group_bb_stub(struct ext4_mark_context *mc, > + ext4_group_t group, ext4_grpblk_t blkoff, > + ext4_grpblk_t len, int flags) > +{ > + struct mb_grp_ctx *grp_ctx = MB_GRP_CTX(mc->sb, group); > + struct buffer_head *bitmap_bh = &grp_ctx->bitmap_bh; > + > + if (mc->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 Rather then defining this statically, can we add a test for testing different options. like for e.g. bs=1k, 4k, and 64k to be tested in a loop or something with maybe diffrent group_count values to start with? At a high level, I went over the code and this looks like a good first start to me. One suggestion is to prefix the mballoc kunit tests with some string to differentiate what is kunit related and what is actual ext4/mballoc calls. Once this kunit test grows, I am sure it will be difficult to make out the differece between test related APIs and actual kernel APIs. maybe something like mbt_ so mb_grp_ctx -> mbt_grp_ctx mb_ctx -> mbt_ctx fake_super_block -> mbt_ext4_super_block alloc/free_fake_super_block -> mbt_ext4_alloc/free_super_block ext4_block_layout -> mbt_ext4_block_layout init_sb_layout -> mbt_init_sb_layout mb_grp_ctx_init/release -> mbt_grp_ctx_init/release mb_ctx_mark_used -> mbt_ctx_mark_used mballoc_test_init -> mbt_kunit_init ext4_mballoc_test_cases -> mbt_test_cases funtions with _stub looks ok to me, as we can clearly differentiate them from actual functions. -ritesh > +static int mballoc_test_init(struct kunit *test) > +{ > + struct 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 = alloc_fake_super_block(); > + if (sb == NULL) > + return -ENOMEM; > + > + init_sb_layout(sb, &layout); > + > + ret = mb_ctx_init(sb); > + if (ret != 0) { > + free_fake_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_group_bb, > + ext4_mb_mark_group_bb_stub); > + return 0; > +} > + > +static void mballoc_test_exit(struct kunit *test) > +{ > + struct super_block *sb = (struct super_block *)test->priv; > + > + mb_ctx_release(sb); > + free_fake_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 */ > + mb_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++) > + mb_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++) > + mb_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 ext4_mballoc_test_cases[] = { > + KUNIT_CASE(test_new_blocks_simple), > + {} > +}; > + > +static struct kunit_suite ext4_mballoc_test_suite = { > + .name = "ext4_mballoc_test", > + .init = mballoc_test_init, > + .exit = mballoc_test_exit, > + .test_cases = ext4_mballoc_test_cases, > +}; > + > +kunit_test_suites(&ext4_mballoc_test_suite); > + > +MODULE_LICENSE("GPL"); > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index dd2fc0546c0b..b6b963412cdc 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -6954,3 +6954,7 @@ ext4_mballoc_query_range( > > return error; > } > + > +#ifdef CONFIG_EXT4_KUNIT_TESTS > +#include "mballoc-test.c" > +#endif > -- > 2.30.0