hugetlb_dio test uses sub-page offsets (pagesize / 2) to verify that
hugepages used as DIO user buffers are correctly unpinned at completion.
However, on filesystems with a logical block size larger than half the
page size (e.g., 4K-sector block devices), these unaligned DIO writes
are rejected with -EINVAL, causing the test to fail unexpectedly.
Add check_dio_alignment() which queries the filesystem's DIO alignment
requirement via statx(STATX_DIOALIGN) and skips the test early if the
sub-page offset used by the test is not compatible with the alignment
constraint.
=== Reproduce Steps ===
# dd if=/dev/zero of=/tmp/test.img bs=1M count=512
# losetup --sector-size 4096 /dev/loop0 /tmp/test.img
# mkfs.xfs /dev/loop0
# mkdir -p /mnt/dio_test
# mount /dev/loop0 /mnt/dio_test
// Modify test to open /mnt/dio_test and rebuild it:
- fd = open("/tmp", O_TMPFILE | O_RDWR | O_DIRECT, 0664);
+ fd = open("/mnt/dio_test", O_TMPFILE | O_RDWR | O_DIRECT, 0664);
# getconf PAGESIZE
4096
# echo 100 >/proc/sys/vm/nr_hugepages
# ./hugetlb_dio
TAP version 13
1..4
# No. Free pages before allocation : 100
# No. Free pages after munmap : 100
ok 1 free huge pages from 0-12288
Bail out! Error writing to file
: Invalid argument (22)
# Planned tests != run tests (4 != 1)
# Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
Signed-off-by: Li Wang <[email protected]>
---
tools/testing/selftests/mm/hugetlb_dio.c | 37 +++++++++++++++++-------
1 file changed, 27 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/mm/hugetlb_dio.c
b/tools/testing/selftests/mm/hugetlb_dio.c
index 9ac62eb4c97d..afcca50d190e 100644
--- a/tools/testing/selftests/mm/hugetlb_dio.c
+++ b/tools/testing/selftests/mm/hugetlb_dio.c
@@ -20,6 +20,31 @@
#include "vm_util.h"
#include "kselftest.h"
+#ifndef STATX_DIOALIGN
+#define STATX_DIOALIGN 0x00002000U
+#endif
+
+void check_dio_alignment(size_t pagesize)
+{
+ int fd;
+ struct statx stx;
+ unsigned int dio_align = 1;
+
+ fd = open("/tmp", O_TMPFILE | O_RDWR, 0664);
+ if (fd < 0)
+ ksft_exit_skip("Unable to allocate file: %s\n",
strerror(errno));
+
+ if (statx(fd, "", AT_EMPTY_PATH, STATX_DIOALIGN, &stx) == 0 &&
+ (stx.stx_mask & STATX_DIOALIGN))
+ dio_align = stx.stx_dio_offset_align;
+
+ close(fd);
+
+ if ((pagesize / 2) % dio_align != 0)
+ ksft_exit_skip("DIO alignment (%u) incompatible with sub-page
offset %lu\n",
+ dio_align, pagesize / 2);
+}
+
void run_dio_using_hugetlb(unsigned int start_off, unsigned int end_off)
{
int fd;
@@ -89,16 +114,11 @@ void run_dio_using_hugetlb(unsigned int start_off,
unsigned int end_off)
int main(void)
{
- size_t pagesize = 0;
- int fd;
+ size_t pagesize = psize();
ksft_print_header();
- /* Open the file to DIO */
- fd = open("/tmp", O_TMPFILE | O_RDWR | O_DIRECT, 0664);
- if (fd < 0)
- ksft_exit_skip("Unable to allocate file: %s\n",
strerror(errno));
- close(fd);
+ check_dio_alignment(pagesize);
/* Check if huge pages are free */
if (!get_free_hugepages())
@@ -106,9 +126,6 @@ int main(void)
ksft_set_plan(4);
- /* Get base page size */
- pagesize = psize();
-
/* start and end is aligned to pagesize */
run_dio_using_hugetlb(0, (pagesize * 3));
--
2.53.0
