Re: [PATCH xfstests] xfs: add tests for XFS_IOC_FSSETXATTR behaviour

Re: [PATCH xfstests] xfs: add tests for XFS_IOC_FSSETXATTR behaviour

[Dave Chinner]

[cc fstests@vger.kernel.org]

On Wed, Aug 27, 2014 at 09:24:00PM -0700, Iustin Pop wrote:
> Add two tests that check for correct behaviour of XFS_IOC_FSSETXATTR:
> 
> - 307: check that extent size can always be set on a directory
> - 308: check that setting a non-zero extent size directly via the ioctl
>   sets the expected flags (EXTSIZE and EXTSZINHERIT)
> 
> Signed-off-by: Iustin Pop <iusty@k1024.org>

Minor stuff first:

- xfstests patches should be sent to fstests@vger.kernel.org now.
- can you pick the first unused numbers in the sequence for new
  tests (xfs/032, xfs/051) so I don't have to renumber them before
  applying them?
- a patch per new test - it makes it easier to review and apply as i
  don't have to split patches into multiple commits...

> diff --git a/tests/xfs/307 b/tests/xfs/307
> new file mode 100755
> index 0000000..e8f3576
> --- /dev/null
> +++ b/tests/xfs/307
> @@ -0,0 +1,87 @@
> +#! /bin/bash
> +# FS QA Test No. 307
> +#
> +# Test that setting extent size on directories work even for large
> +# directories.

What is a "large directory"? Wouldn't it be better to describe the
test as "Determine whether the extent size hint can be set on
directories with allocated extents correctly"?

> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2014 Google Inc.  All Rights Reserved.

Is that correct? It doesn't match the email address you sent this
from and I've never seen you post from a @google.com address.  I
always like to check that the copyright assignment is correct in
situations like this...

> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs xfs
> +_supported_os Linux
> +_require_test

Not needed, doesn't use the test device.

> +_require_scratch
> +
> +_scratch_mkfs_xfs >/dev/null 2>&1
> +_scratch_mount
> +
> +small=$SCRATCH_MNT/small
> +big=$SCRATCH_MNT/big
> +
> +# sanity check on a small directory
> +mkdir $small
> +# expect that an empty directory has no extents
> +xfs_bmap $small | grep -q "no extents"

Better to use xfs_io directly and filter out $SCRATCH_MNT into the
golden output file like so:

$XFS_IO_PROG -c "bmap" $small | _filter_scratch

which will give:

SCRATCH_MNT/small: no extents

> +# and that we can set an extent size on it
> +xfs_io -c 'extsize 8m' $small

$XFS_IO_PROG

> +# and finally check that the extent size update has taken place
> +(cd $SCRATCH_MNT; xfs_io -c 'extsize' small)

$XFS_IO_PROG -c 'extsize' $small | _filter_scratch

> +# now create a 'big' (with extents) directory
> +mkdir $big
> +idx=1
> +while xfs_bmap $big | grep -q "no extents"; do
> +	touch $big/$idx
> +	idx=$((idx+1))
> +	if [ "$idx" -gt 1048576 ]; then
> +		# still no extents? giving up
> +		echo "Can't make a directory to have extents even after 1M files" 1>&2
> +		exit
> +	fi
> +done

urk. largest inode size is 2kb, which means at most it can fit less
than 100 dirents in the inode before spilling to extent form. So
just do a loop that creates 1000 files - there's no need to
overengineer the test code.

> +# expect that we can set the extent size on $big as well
> +xfs_io -c 'extsize 8m' $big

$XFS_IO_PROG

> +# and that it took effect
> +(cd $SCRATCH_MNT; xfs_io -c 'extsize' big)

$XFS_IO_PROG -c 'extsize' $big | _filter_scratch

> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/xfs/307.out b/tests/xfs/307.out
> new file mode 100644
> index 0000000..f825525
> --- /dev/null
> +++ b/tests/xfs/307.out
> @@ -0,0 +1,3 @@
> +QA output created by 307
> +[8388608] small
> +[8388608] big
> diff --git a/tests/xfs/308 b/tests/xfs/308
> new file mode 100755
> index 0000000..7b43836
> --- /dev/null
> +++ b/tests/xfs/308
> @@ -0,0 +1,98 @@
> +#! /bin/bash
> +# FS QA Test No. 308
> +#
> +# Test that setting extent size on files and directories (directly via
> +# ioctl and not via xfs_io) sets the correct flags.

xfs_io uses the ioctl directly - there's no need to write a special
c program to do this, especially as....

> +touch $file
> +mkdir $dir
> +
> +cat > $cprog << EOF
> +#include <stdio.h>
> +#include <xfs/xfs.h>
> +
> +int main(int argc, char **argv) {
> +	struct fsxattr fa;
> +	int fd = open(argv[1], O_RDONLY);
> +	if (fd < 0) {
> +		perror("open");
> +		return 1;
> +	}
> +	fa.fsx_xflags = 0;
> +	fa.fsx_extsize = 1048576 * 8;
> +	int r = xfsctl(argv[1], fd, XFS_IOC_FSSETXATTR, &fa);

.... that code is quite broken. Yes, it would work to set the
appropriate extent size flags with the kernel
changes you made, but that's not how this ioctl works.

i.e. it will cause any flag bits that are set on the inode to be
cleared and it's likely to fail on old kernels beacuse they have
very different behaviour to what your patch does.

IOWs, setting fsx_extsize without setting either XFS_XFLAG_EXTSIZE
or XFS_XFLAG_EXTSZINHERIT is bad practice. The kernel is left to
guess what you actually wanted to be done - the flags are supposed
to tell the kernel that the fsx_extsize value is meaningful, not the
other way around.

FWIW, the xfs_io code is *exactly* what applications should be
doing to set the extent size or any other inode flag. i.e:

1. stat the fd to determine the type.
2. populate the fsxattr structure with the existing inode flags
3. change the flags/fields of the fsxattr structure appropriately
4. set the new values to the inode.

i.e, from io/open.c:

static int
set_extsize(const char *path, int fd, long extsz)
{
        struct fsxattr  fsx;
        struct stat64   stat;

        if (fstat64(fd, &stat) < 0) {
                perror("fstat64");
                return 0;
        }
        if ((xfsctl(path, fd, XFS_IOC_FSGETXATTR, &fsx)) < 0) {
                printf("%s: XFS_IOC_FSGETXATTR %s: %s\n",
                        progname, path, strerror(errno));
                return 0;
        }

        if (S_ISREG(stat.st_mode)) {
                fsx.fsx_xflags |= XFS_XFLAG_EXTSIZE;
        } else if (S_ISDIR(stat.st_mode)) {
                fsx.fsx_xflags |= XFS_XFLAG_EXTSZINHERIT;
        } else {
                printf(_("invalid target file type - file %s\n"), path);
                return 0;
        }
        fsx.fsx_extsize = extsz;

        if ((xfsctl(path, fd, XFS_IOC_FSSETXATTR, &fsx)) < 0) {
                printf("%s: XFS_IOC_FSSETXATTR %s: %s\n",
                        progname, path, strerror(errno));
                return 0;
        }

        return 0;
}

We have xfs_io precisely so that we don't have to maintain random
test code like this throughout xfstests - do it once, do it right,
use it everywhere.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

Re: [PATCH xfstests] xfs: add tests for XFS_IOC_FSSETXATTR behaviour

[Iustin Pop]

On Don, Aug 28, 2014 at 08:16:28 +1000, Dave Chinner wrote:
> [cc fstests@vger.kernel.org]
> 
> On Wed, Aug 27, 2014 at 09:24:00PM -0700, Iustin Pop wrote:
> > Add two tests that check for correct behaviour of XFS_IOC_FSSETXATTR:
> > 
> > - 307: check that extent size can always be set on a directory
> > - 308: check that setting a non-zero extent size directly via the ioctl
> >   sets the expected flags (EXTSIZE and EXTSZINHERIT)
> > 
> > Signed-off-by: Iustin Pop <iusty@k1024.org>
> 
> Minor stuff first:
> 
> - xfstests patches should be sent to fstests@vger.kernel.org now.

OK, will do. There was nothing written in the git repository's README,
hence I chose what I thought best.

> - can you pick the first unused numbers in the sequence for new
>   tests (xfs/032, xfs/051) so I don't have to renumber them before
>   applying them?

Will do - this is what the 'new' script did (or tried to do, as it
doesn't seem to work reliably).

> - a patch per new test - it makes it easier to review and apply as i
>   don't have to split patches into multiple commits...

Will do so when resending.

> > diff --git a/tests/xfs/307 b/tests/xfs/307
> > new file mode 100755
> > index 0000000..e8f3576
> > --- /dev/null
> > +++ b/tests/xfs/307
> > @@ -0,0 +1,87 @@
> > +#! /bin/bash
> > +# FS QA Test No. 307
> > +#
> > +# Test that setting extent size on directories work even for large
> > +# directories.
> 
> What is a "large directory"? Wouldn't it be better to describe the
> test as "Determine whether the extent size hint can be set on
> directories with allocated extents correctly"?

Indeed that's better, I'll update.

> > +#
> > +#-----------------------------------------------------------------------
> > +# Copyright (c) 2014 Google Inc.  All Rights Reserved.
> 
> Is that correct? It doesn't match the email address you sent this
> from and I've never seen you post from a @google.com address.  I
> always like to check that the copyright assignment is correct in
> situations like this...

It is correct indeed (and thanks for double-checking). I prefer to send
my interactions/contributions done not as part of my job using my
personal address (hence I always wrote to xfs@ from the same address),
but even in that case, the copyright remains with my employer.

Just as a confirmation, sending this email from my @google.com address.

> > +# real QA test starts here
> > +
> > +# Modify as appropriate.
> > +_supported_fs xfs
> > +_supported_os Linux
> > +_require_test
> 
> Not needed, doesn't use the test device.

Ack.

> > +_require_scratch
> > +
> > +_scratch_mkfs_xfs >/dev/null 2>&1
> > +_scratch_mount
> > +
> > +small=$SCRATCH_MNT/small
> > +big=$SCRATCH_MNT/big
> > +
> > +# sanity check on a small directory
> > +mkdir $small
> > +# expect that an empty directory has no extents
> > +xfs_bmap $small | grep -q "no extents"
> 
> Better to use xfs_io directly and filter out $SCRATCH_MNT into the
> golden output file like so:
> 
> $XFS_IO_PROG -c "bmap" $small | _filter_scratch
> 
> which will give:
> 
> SCRATCH_MNT/small: no extents

Oh, nice, thanks!

> > +# and that we can set an extent size on it
> > +xfs_io -c 'extsize 8m' $small
> 
> $XFS_IO_PROG

Ack.

> > +# and finally check that the extent size update has taken place
> > +(cd $SCRATCH_MNT; xfs_io -c 'extsize' small)
> 
> $XFS_IO_PROG -c 'extsize' $small | _filter_scratch

Ack.

> > +# now create a 'big' (with extents) directory
> > +mkdir $big
> > +idx=1
> > +while xfs_bmap $big | grep -q "no extents"; do
> > +	touch $big/$idx
> > +	idx=$((idx+1))
> > +	if [ "$idx" -gt 1048576 ]; then
> > +		# still no extents? giving up
> > +		echo "Can't make a directory to have extents even after 1M files" 1>&2
> > +		exit
> > +	fi
> > +done
> 
> urk. largest inode size is 2kb, which means at most it can fit less
> than 100 dirents in the inode before spilling to extent form. So
> just do a loop that creates 1000 files - there's no need to
> overengineer the test code.

Will do.  It's fine to still check that the directory does have extents,
I hope?

> > +# expect that we can set the extent size on $big as well
> > +xfs_io -c 'extsize 8m' $big
> 
> $XFS_IO_PROG

Ack.

> > +# and that it took effect
> > +(cd $SCRATCH_MNT; xfs_io -c 'extsize' big)
> 
> $XFS_IO_PROG -c 'extsize' $big | _filter_scratch

Ack.

> > +# success, all done
> > +status=0
> > +exit
> > diff --git a/tests/xfs/307.out b/tests/xfs/307.out
> > new file mode 100644
> > index 0000000..f825525
> > --- /dev/null
> > +++ b/tests/xfs/307.out
> > @@ -0,0 +1,3 @@
> > +QA output created by 307
> > +[8388608] small
> > +[8388608] big
> > diff --git a/tests/xfs/308 b/tests/xfs/308
> > new file mode 100755
> > index 0000000..7b43836
> > --- /dev/null
> > +++ b/tests/xfs/308
> > @@ -0,0 +1,98 @@
> > +#! /bin/bash
> > +# FS QA Test No. 308
> > +#
> > +# Test that setting extent size on files and directories (directly via
> > +# ioctl and not via xfs_io) sets the correct flags.
> 
> xfs_io uses the ioctl directly - there's no need to write a special
> c program to do this, especially as....
> 
> > +touch $file
> > +mkdir $dir
> > +
> > +cat > $cprog << EOF
> > +#include <stdio.h>
> > +#include <xfs/xfs.h>
> > +
> > +int main(int argc, char **argv) {
> > +	struct fsxattr fa;
> > +	int fd = open(argv[1], O_RDONLY);
> > +	if (fd < 0) {
> > +		perror("open");
> > +		return 1;
> > +	}
> > +	fa.fsx_xflags = 0;
> > +	fa.fsx_extsize = 1048576 * 8;
> > +	int r = xfsctl(argv[1], fd, XFS_IOC_FSSETXATTR, &fa);
> 
> .... that code is quite broken. Yes, it would work to set the
> appropriate extent size flags with the kernel
> changes you made, but that's not how this ioctl works.
> 
> i.e. it will cause any flag bits that are set on the inode to be
> cleared

Good point…

> and it's likely to fail on old kernels beacuse they have
> very different behaviour to what your patch does.

OK, that I didn't know. (Would you mind quickly explaining?)

> IOWs, setting fsx_extsize without setting either XFS_XFLAG_EXTSIZE
> or XFS_XFLAG_EXTSZINHERIT is bad practice. The kernel is left to
> guess what you actually wanted to be done - the flags are supposed
> to tell the kernel that the fsx_extsize value is meaningful, not the
> other way around.

See below.

> FWIW, the xfs_io code is *exactly* what applications should be
> doing to set the extent size or any other inode flag. i.e:
> 
> 1. stat the fd to determine the type.
> 2. populate the fsxattr structure with the existing inode flags
> 3. change the flags/fields of the fsxattr structure appropriately
> 4. set the new values to the inode.
> 
> i.e, from io/open.c:
> 
> static int
> set_extsize(const char *path, int fd, long extsz)
> {
>         struct fsxattr  fsx;
>         struct stat64   stat;
> 
>         if (fstat64(fd, &stat) < 0) {
>                 perror("fstat64");
>                 return 0;
>         }
>         if ((xfsctl(path, fd, XFS_IOC_FSGETXATTR, &fsx)) < 0) {
>                 printf("%s: XFS_IOC_FSGETXATTR %s: %s\n",
>                         progname, path, strerror(errno));
>                 return 0;
>         }
> 
>         if (S_ISREG(stat.st_mode)) {
>                 fsx.fsx_xflags |= XFS_XFLAG_EXTSIZE;
>         } else if (S_ISDIR(stat.st_mode)) {
>                 fsx.fsx_xflags |= XFS_XFLAG_EXTSZINHERIT;
>         } else {
>                 printf(_("invalid target file type - file %s\n"), path);
>                 return 0;
>         }
>         fsx.fsx_extsize = extsz;
> 
>         if ((xfsctl(path, fd, XFS_IOC_FSSETXATTR, &fsx)) < 0) {
>                 printf("%s: XFS_IOC_FSSETXATTR %s: %s\n",
>                         progname, path, strerror(errno));
>                 return 0;
>         }
> 
>         return 0;
> }
> 
> We have xfs_io precisely so that we don't have to maintain random
> test code like this throughout xfstests - do it once, do it right,
> use it everywhere.

I totally agree that xfs_io is what people should use, but I disagree on
the use of xfs_io in this particular test, let me explain why.

With 3.16-rc1 at least, it is possible to set fsx_extsize to a non-zero
value, without setting the flags (if you call the ioctl directly). Such
an inode  will be (unless I'm mistaken) flagged with a warning by
xfs_repair, which means that it's an invalid inode state.

So in my view, there's a kernel bug, in that it allows a user land
application to put an inode into a "wrong" state. This particular test
is designed to reproduce this kernel bug, so that the kernel fix can be
verified that is indeed a fix.

I can't use xfs_io here, because it will do the "right" thing - set the
EXTSIZE/EXTSZINHERIT flags correctly; but this is a test that the kernel
protects the inode invariants, not that xfs_io does so.

Alternatively, you could say that it's perfectly fine to have a non-zero
fsx_extsize, and that only when the flag is set it should be taken into
account; but I don't think that is what the rest of the code expects
today.

So, I'm fine either way, but I would to fix this so that all the code
agrees what the correct states for an inode are, and that the kernel
prevents user space from violating this assumption via a (documented)
ioctl. Just let me know which are the correct states.

Thanks for the feedback, and for such a quick reply.

iustin

Re: [PATCH xfstests] xfs: add tests for XFS_IOC_FSSETXATTR behaviour

[Dave Chinner]

On Thu, Aug 28, 2014 at 03:28:54PM -0700, Iustin Pop wrote:
> On Don, Aug 28, 2014 at 08:16:28 +1000, Dave Chinner wrote:
> > [cc fstests@vger.kernel.org]
> > 
> > On Wed, Aug 27, 2014 at 09:24:00PM -0700, Iustin Pop wrote:
> > > Add two tests that check for correct behaviour of XFS_IOC_FSSETXATTR:
> > > 
> > > - 307: check that extent size can always be set on a directory
> > > - 308: check that setting a non-zero extent size directly via the ioctl
> > >   sets the expected flags (EXTSIZE and EXTSZINHERIT)
> > > 
> > > Signed-off-by: Iustin Pop <iusty@k1024.org>
> > 
> > Minor stuff first:
> > 
> > - xfstests patches should be sent to fstests@vger.kernel.org now.
> 
> OK, will do. There was nothing written in the git repository's README,
> hence I chose what I thought best.

Documentation always needs updating, and stuff is in the process of
being moved around.

> > > +# Copyright (c) 2014 Google Inc.  All Rights Reserved.
> > 
> > Is that correct? It doesn't match the email address you sent this
> > from and I've never seen you post from a @google.com address.  I
> > always like to check that the copyright assignment is correct in
> > situations like this...
> 
> It is correct indeed (and thanks for double-checking). I prefer to send
> my interactions/contributions done not as part of my job using my
> personal address (hence I always wrote to xfs@ from the same address),
> but even in that case, the copyright remains with my employer.
> 
> Just as a confirmation, sending this email from my @google.com address.

Thanks, I'll know in future ;)

> > > +# now create a 'big' (with extents) directory
> > > +mkdir $big
> > > +idx=1
> > > +while xfs_bmap $big | grep -q "no extents"; do
> > > +	touch $big/$idx
> > > +	idx=$((idx+1))
> > > +	if [ "$idx" -gt 1048576 ]; then
> > > +		# still no extents? giving up
> > > +		echo "Can't make a directory to have extents even after 1M files" 1>&2
> > > +		exit
> > > +	fi
> > > +done
> > 
> > urk. largest inode size is 2kb, which means at most it can fit less
> > than 100 dirents in the inode before spilling to extent form. So
> > just do a loop that creates 1000 files - there's no need to
> > overengineer the test code.
> 
> Will do.  It's fine to still check that the directory does have extents,
> I hope?

$XFS_IO_PROG -c 'bmap -vp' $big | _filter_bmap

> > > +int main(int argc, char **argv) {
> > > +	struct fsxattr fa;
> > > +	int fd = open(argv[1], O_RDONLY);
> > > +	if (fd < 0) {
> > > +		perror("open");
> > > +		return 1;
> > > +	}
> > > +	fa.fsx_xflags = 0;
> > > +	fa.fsx_extsize = 1048576 * 8;
> > > +	int r = xfsctl(argv[1], fd, XFS_IOC_FSSETXATTR, &fa);
> > 
> > .... that code is quite broken. Yes, it would work to set the
> > appropriate extent size flags with the kernel
> > changes you made, but that's not how this ioctl works.
> > 
> > i.e. it will cause any flag bits that are set on the inode to be
> > cleared
> 
> Good point…
> 
> > and it's likely to fail on old kernels beacuse they have
> > very different behaviour to what your patch does.
> 
> OK, that I didn't know. (Would you mind quickly explaining?)

The extsize hint on the inode is not used by the kernel code unless
the XFS_XFLAG_EXTSIZE is also set. So existing kernels may set the
inode extszhint field, but the code will ignore it because the flags
didn't get set on the inode. See xfs_get_extsz_hint().

With your kernel changes, the above *invalid* code will result in
the flags being set on the inode, and so there's a change of
behaviour from "old kernel, does not trigger extsz behaviour" to
"new kernel, extsz behaviour is invoked".

> > We have xfs_io precisely so that we don't have to maintain random
> > test code like this throughout xfstests - do it once, do it right,
> > use it everywhere.
> 
> I totally agree that xfs_io is what people should use, but I disagree on
> the use of xfs_io in this particular test, let me explain why.
> 
> With 3.16-rc1 at least, it is possible to set fsx_extsize to a non-zero
> value, without setting the flags (if you call the ioctl directly). Such
> an inode  will be (unless I'm mistaken) flagged with a warning by
> xfs_repair, which means that it's an invalid inode state.

Yes, since this commit bd5683f ("xfs_repair: validate inode di_flags
field") in 2011 repair will flag that the hint is non-zero but the
correct flags are not set. Likewise it will warn if the wrong flags
are set. You can get wrong flags set on the inode in many ways, but
historically the kernel and repair utilities haven't cared.

> So in my view, there's a kernel bug, in that it allows a user land
> application to put an inode into a "wrong" state. This particular test
> is designed to reproduce this kernel bug, so that the kernel fix can be
> verified that is indeed a fix.

Yes this is not what xfstests is for. If we fix an API bug, there's
little value to testing forever that the API is fixed. What we are
trying to cover is that when the parameters are set correctly that
the behaviour is correct.

If you want to do "is the API validating user input correctly"
testing then that's what trinity is for. Dave Jones has long wanted
to get better ioctl coverage for filesystem specific operations, so
I'd suggest that this is the avenue for testing whether an API
behaves correctly and catches all invalid input.

Then we get to fix all the problems that trinity causes, just like
the mm folk have been doing for the past couple of years...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

[PATCH] xfs: add test for XFS_IOC_FSSETXATTR behaviour

[Iustin Pop]

Adds a new test (xfs/032) that checks for correct behaviour of
XFS_IOC_FSSETXATTR for directories: extent sizes should always be
settable on a directory, even if the directory already has allocated
extents.

Signed-off-by: Iustin Pop <iustin@k1024.org>
---
 Note that I've dropped the other test, since - thanks to your explanations - I
 understood that it was meaningless (and why).

 tests/xfs/032     | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/032.out |  4 +++
 tests/xfs/group   |  1 +
 3 files changed, 88 insertions(+)
 create mode 100755 tests/xfs/032
 create mode 100644 tests/xfs/032.out

diff --git a/tests/xfs/032 b/tests/xfs/032
new file mode 100755
index 0000000..3afce26
--- /dev/null
+++ b/tests/xfs/032
@@ -0,0 +1,83 @@
+#! /bin/bash
+# FS QA Test No. 032
+#
+# Determine whether the extent size hint can be set on directories
+# with allocated extents correctly.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2014 Google Inc.  All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+#
+
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+    cd /
+    rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/punch
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs xfs
+_supported_os Linux
+_require_scratch
+
+_scratch_mkfs_xfs >/dev/null 2>&1
+_scratch_mount
+
+small=$SCRATCH_MNT/small
+big=$SCRATCH_MNT/big
+
+# sanity check on a small directory
+mkdir $small
+# expect that an empty directory has no extents
+$XFS_IO_PROG -c "bmap" $small | _filter_scratch
+# and that we can set an extent size on it
+$XFS_IO_PROG -c 'extsize 8m' $small
+# and finally check that the extent size update has taken place
+$XFS_IO_PROG -c "extsize" $small | _filter_scratch
+
+# now create a 'big' (with extents) directory
+mkdir $big
+for idx in {0..1000}; do
+    touch $big/$idx
+done
+$XFS_IO_PROG -c 'bmap -vp' $big | _filter_bmap | \
+    grep -q '^0: .*data'
+[ $? -eq 0 ] || echo "Can't force allocating extents!" 1>&2
+
+# expect that we can set the extent size on $big as well
+$XFS_IO_PROG -c 'extsize 8m' $big | _filter_scratch
+# and that it took effect
+$XFS_IO_PROG -c 'extsize' $big | _filter_scratch
+
+# success, all done
+status=0
+exit
diff --git a/tests/xfs/032.out b/tests/xfs/032.out
new file mode 100644
index 0000000..4b7bd92
--- /dev/null
+++ b/tests/xfs/032.out
@@ -0,0 +1,4 @@
+QA output created by 032
+SCRATCH_MNT/small: no extents
+[8388608] SCRATCH_MNT/small
+[8388608] SCRATCH_MNT/big
diff --git a/tests/xfs/group b/tests/xfs/group
index 4b8e51a..dc132b5 100644
--- a/tests/xfs/group
+++ b/tests/xfs/group
@@ -29,6 +29,7 @@
 029 mkfs logprint log auto quick
 030 repair auto quick
 031 repair mkfs auto quick
+032 ioctl quick
 033 repair auto quick
 034 other auto quick
 035 dump ioctl tape auto
-- 
2.1.3