Re: [LTP] [PATCH v2] fallocate04: another check if SEEK_HOLE is not supported

Jan Stancek
2015-05-20T11:32:36Z

----- Original Message -----
> From: "Zeng Linggang" <zenglg.jy@cn.fujitsu.com>
> To: "Jan Stancek" <jstancek@redhat.com>
> Cc: "Alexey Kodanev" <alexey.kodanev@oracle.com>, "vasily isaenko" <vasily.isaenko@oracle.com>,
> ltp-list@lists.sourceforge.net
> Sent: Wednesday, 20 May, 2015 11:58:01 AM
> Subject: Re: [LTP] [PATCH v2] fallocate04: another check if SEEK_HOLE is not supported
>
> Hi,
>
> On Wed, 2015-05-20 at 02:52 -0400, Jan Stancek wrote:
> >
> >
> >
> > ----- Original Message -----
> > > From: "Zeng Linggang" <zenglg.jy@cn.fujitsu.com>
> > > To: "Jan Stancek" <jstancek@redhat.com>
> > > Cc: "Alexey Kodanev" <alexey.kodanev@oracle.com>, "vasily isaenko"
> > > <vasily.isaenko@oracle.com>,
> > > ltp-list@lists.sourceforge.net
> > > Sent: Wednesday, 20 May, 2015 3:47:22 AM
> > > Subject: Re: [LTP] [PATCH v2] fallocate04: another check if SEEK_HOLE is
> > > not supported
> > >
> > > Hi!
> > >
> > > On Tue, 2015-05-19 at 07:18 -0400, Jan Stancek wrote:
> > > >
> > > >
> > > >
> > > > ----- Original Message -----
> > > > > From: "Zeng Linggang" <zenglg.jy@cn.fujitsu.com>
> > > > > To: "Alexey Kodanev" <alexey.kodanev@oracle.com>
> > > > > Cc: "vasily isaenko" <vasily.isaenko@oracle.com>,
> > > > > ltp-list@lists.sourceforge.net
> > > > > Sent: Tuesday, 19 May, 2015 10:50:22 AM
> > > > > Subject: [LTP] [PATCH v2] fallocate04: another check if SEEK_HOLE is
> > > > > not
> > > > > supported
> > > > >
> > > > > SEEK_HOLE is only supported since version 3.1. Check the specified
> > > > > range blocks are zeroed while the kernel does not supported
> > > > > SEEK_HOLE.
> > > > >
> > > > > Signed-off-by: Zhang Jin <jy_zhangjin@cn.fujitsu.com>
> > > > > ---
> > > > > testcases/kernel/syscalls/fallocate/fallocate04.c | 13 ++++++++++---
> > > > > 1 file changed, 10 insertions(+), 3 deletions(-)
> > > > >
> > > > > diff --git a/testcases/kernel/syscalls/fallocate/fallocate04.c
> > > > > b/testcases/kernel/syscalls/fallocate/fallocate04.c
> > > > > index 911bbe8..e94c572 100644
> > > > > --- a/testcases/kernel/syscalls/fallocate/fallocate04.c
> > > > > +++ b/testcases/kernel/syscalls/fallocate/fallocate04.c
> > > > > @@ -98,13 +98,13 @@ static void setup(void)
> > > > > get_blocksize();
> > > > > }
> > > > >
> > > > > -static void check_file_data(const char exp_buf[], size_t size)
> > > > > +static void check_file_data_(const char exp_buf[], size_t size,
> > > > > off_t
> > > > > offset)
> > > > > {
> > > > > char rbuf[size];
> > > > >
> > > > > tst_resm(TINFO, "reading the file, compare with expected buffer");
> > > > >
> > > > > - SAFE_LSEEK(cleanup, fd, 0, SEEK_SET);
> > > > > + SAFE_LSEEK(cleanup, fd, offset, SEEK_SET);
> > > > > SAFE_READ(cleanup, 1, fd, rbuf, size);
> > > > >
> > > > > if (memcmp(exp_buf, rbuf, size)) {
> > > > > @@ -116,6 +116,11 @@ static void check_file_data(const char
> > > > > exp_buf[],
> > > > > size_t
> > > > > size)
> > > > > }
> > > > > }
> > > > >
> > > > > +static inline void check_file_data(const char exp_buf[], size_t
> > > > > size)
> > > > > +{
> > > > > + check_file_data_(exp_buf, size, 0);
> > > > > +}
> > > > > +
> > > > > static void test01(void)
> > > > > {
> > > > > tst_resm(TINFO, "allocate '%zu' bytes", buf_size);
> > > > > @@ -158,7 +163,9 @@ static void test02(void)
> > > > > tst_brkm(TFAIL | TERRNO, cleanup,
> > > > > "fallocate() or lseek() failed");
> > > > > }
> > > > > - tst_resm(TWARN | TERRNO, "lseek() doesn't support SEEK_HOLE");
> > > > > + char zeros[block_size];
> > > > > + memset(zeros, 0, block_size);
> > > > > + check_file_data_(zeros, block_size, block_size);
> > > >
> > > > Hi,
> > > >
> > > > Isn't this redundant?
> > >
> > > To be honest, I do not think it is redundant.
> >
> > Can you explain why?
> >
> > >
> > > >
> > > > Couple lines below is this check, which also checks that range
> > > > <block_size, block_size*2> is zeroed.
> > >
> > > Yep, this looks simple.
> > > This maybe cost more runtime because of 'fill_tst_buf'.
> > > But I do not reject it.
> >
> > That code is already there, your patch is not removing it.
> >
> > >
> > > >
> > > > char exp_buf[buf_size];
> > > >
> > > > fill_tst_buf(exp_buf);
> > > > memset(exp_buf + block_size, 0, block_size);
> > > > check_file_data(exp_buf, buf_size);
> > > >
> > > > Wouldn't it be enough to turn that warning into TINFO, for kernels <
> > > > 3.1?
> > > >
> > > > diff --git a/testcases/kernel/syscalls/fallocate/fallocate04.c
> > > > b/testcases/kernel/syscalls/fallocate/fallocate04.c
> > > > index 911bbe8..45d9827 100644
> > > > --- a/testcases/kernel/syscalls/fallocate/fallocate04.c
> > > > +++ b/testcases/kernel/syscalls/fallocate/fallocate04.c
> > > > @@ -158,9 +158,12 @@ static void test02(void)
> > > > tst_brkm(TFAIL | TERRNO, cleanup,
> > > > "fallocate() or lseek() failed");
> > > > }
> > > > - tst_resm(TWARN | TERRNO, "lseek() doesn't support
> > > > SEEK_HOLE");
> > > > + if (tst_kvercmp(3, 1, 0) < 0)
> > >
> > > How about put them before lseek(SEEK_HOLE) ?
> >
> > I think we should do the check on all kernels. lseek() can only check that
> > the
> > hole exists, but current check also verifies that hole has correct size and
> > content.
> >
>
> Right. It is the strict way we need to do. But it would make the test
> complex.

I think we already check it strictly, see line 172-177. This covers blocks 1,2,3.
The patch you proposed _adds_ one more check only for zero-ed block 2.
My objection was that this seems redundant, because we already have
a check (line 172-177), which covers all 3 blocks. Am I missing something?

> Now, "turn that warning into TINFO" looks simple but effective.
> If nobody reject, I will send new patch like:

Looks OK to me, though maybe it should TBROK on kernels > 3.1 even when
errno is EINVAL.

Regards,
Jan

>
> - tst_resm(TWARN | TERRNO, "lseek() doesn't support
> SEEK_HOLE");
> + if (tst_kvercmp(3, 1, 0) < 0)
> + tst_resm(TINFO, "lseek() doesn't support SEEK_HOLE, "
> + "this is expected for < 3.1 kernels");
> + } else {
> + tst_resm(TINFO, "found a hole at '%ld' offset", ret);
> }
> - tst_resm(TINFO, "found a hole at '%ld' offset", ret);
>
> Thank you.
>
> Best regards,
> Zeng
>
>
> > Regards,
> > Jan
> …