On Wed, Aug 07, 2019 at 01:25:14PM +0200, Andreas Gruenbacher wrote:
> In test_basic_support, commit f3c1bca7fb25 ("generic: Test that
> SEEK_HOLE can find a punched hole") cleverly punched a hole in the test
> file in the middle of the check for unwritten extent support, making
> sure we would never detect when unwritten extent support is missing.
> Fix that.
>
> While at it, explicitly check for SEEK_DATA support as well: so far, we
> were assuming that SEEK_HOLE support implies SEEK_DATA support, but it
> won't hurt to actually check.
>
> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Thanks for the fix! I missed the bug when reviewing f3c1bca7fb25, I
think that's because it's not so obvious that the fallocate and the
subsequent SEEK_DATA as a whole are for check for unwritten extent
support. So I did minor updates based on this patch to add more
comments, to make it clear what we're checking for at each stage.
Thanks,
Eryu
> ---
> src/seek_sanity_test.c | 27 +++++++++++++++++++--------
> 1 file changed, 19 insertions(+), 8 deletions(-)
>
> diff --git a/src/seek_sanity_test.c b/src/seek_sanity_test.c
> index 30e996e2..080ca7eb 100644
> --- a/src/seek_sanity_test.c
> +++ b/src/seek_sanity_test.c
> @@ -1156,7 +1156,16 @@ static int test_basic_support(void)
> if (ret)
> goto out;
>
> - /* Is SEEK_DATA and SEEK_HOLE supported in the kernel? */
> + /* Is SEEK_DATA supported in the kernel? */
> + pos = lseek(fd, 0, SEEK_DATA);
> + if (pos == -1) {
> + fprintf(stderr, "Kernel does not support llseek(2) extension "
> + "SEEK_DATA. Aborting.\n");
> + ret = -1;
> + goto out;
> + }
> +
> + /* Is SEEK_HOLE supported in the kernel? */
> pos = lseek(fd, 0, SEEK_HOLE);
> if (pos == -1) {
> fprintf(stderr, "Kernel does not support llseek(2) extension "
> @@ -1186,19 +1195,21 @@ static int test_basic_support(void)
> ret = -1;
> }
> goto out;
> - } else if (fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
> - 0, alloc_size) == -1) {
> - fprintf(stderr, "File system does not support punch hole.\n");
> - } else {
> - punch_hole = 1;
> }
>
> pos = lseek(fd, 0, SEEK_DATA);
> if (pos == 0) {
> fprintf(stderr, "File system does not support unwritten extents.\n");
> - goto out;
> + } else {
> + unwritten_extents = 1;
> + }
> +
> + if (fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
> + 0, alloc_size) == -1) {
> + fprintf(stderr, "File system does not support punch hole.\n");
> + } else {
> + punch_hole = 1;
> }
> - unwritten_extents = 1;
>
> printf("\n");
>
> --
> 2.20.1
>
