The st_blocks field reported by fstat should reflect the number of allocated 512-byte blocks for the guest memfd file.
Extend the fallocate test to verify that st_blocks is correctly updated when memory is allocated or deallocated via fallocate(FALLOC_FL_PUNCH_HOLE). Add checks after each fallocate call to ensure that st_blocks increases on allocation, decreases when a hole is punched, and is restored when the hole is re-allocated. Also verify that st_blocks remains unchanged for failing fallocate calls. Signed-off-by: Ackerley Tng <[email protected]> --- tools/testing/selftests/kvm/guest_memfd_test.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index 81387f06e770a..89228d73fa736 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -218,41 +218,58 @@ static void test_file_size(int fd, size_t total_size) TEST_ASSERT_EQ(sb.st_blksize, page_size); } +static void assert_st_blocks_matches_size(int fd, size_t expected_size) +{ + struct stat sb; + + kvm_fstat(fd, &sb); + TEST_ASSERT_EQ(sb.st_blocks, expected_size / 512); +} + static void test_fallocate(int fd, size_t total_size) { int ret; ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, total_size); TEST_ASSERT(!ret, "fallocate with aligned offset and size should succeed"); + assert_st_blocks_matches_size(fd, total_size); ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, page_size - 1, page_size); TEST_ASSERT(ret, "fallocate with unaligned offset should fail"); + assert_st_blocks_matches_size(fd, total_size); ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, total_size, page_size); TEST_ASSERT(ret, "fallocate beginning at total_size should fail"); + assert_st_blocks_matches_size(fd, total_size); ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, total_size + page_size, page_size); TEST_ASSERT(ret, "fallocate beginning after total_size should fail"); + assert_st_blocks_matches_size(fd, total_size); ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, total_size, page_size); TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) at total_size should succeed"); + assert_st_blocks_matches_size(fd, total_size); ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, total_size + page_size, page_size); TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) after total_size should succeed"); + assert_st_blocks_matches_size(fd, total_size); ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, page_size, page_size - 1); TEST_ASSERT(ret, "fallocate with unaligned size should fail"); + assert_st_blocks_matches_size(fd, total_size); ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, page_size, page_size); TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) with aligned offset and size should succeed"); + assert_st_blocks_matches_size(fd, total_size - page_size); ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, page_size, page_size); TEST_ASSERT(!ret, "fallocate to restore punched hole should succeed"); + assert_st_blocks_matches_size(fd, total_size); } static void test_invalid_punch_hole(int fd, size_t total_size) -- 2.53.0.345.g96ddfc5eaa-goog
