Re: [PATCH] generic/645: Confirm availability of free inodes

On Wed, Jul 29, 2026 at 08:44:51AM -0700, Darrick J. Wong wrote:
> On Wed, Jul 29, 2026 at 11:06:57AM +0530, Ojaswin Mujoo wrote:
> > On Thu, Jun 25, 2026 at 11:42:59AM -0700, Darrick J. Wong wrote:
> > > On Wed, Jun 17, 2026 at 11:12:16AM +0530, Ojaswin Mujoo wrote:
> > > > When running generic/645 with ext4 using 64k block size + bigalloc, the
> > > > test fails with ENOSPC because the filesystem runs out of inodes before
> > > > the test completes.
> > > > 
> > > > The test creates approximately 10,001 files, however, in this particular
> > > > configuration a standard 5G FS only has around ~5100 inodes resulting in
> > > > the ENOSPC failure.
> > > > 
> > > > Add a check using _get_free_inode() to verify sufficient inodes are
> > > > available before running the test, else skip it.
> > > > 
> > > > Reported-by: Disha Goel <[email protected]>
> > > > Signed-off-by: Ojaswin Mujoo <[email protected]>
> > > > ---
> > > >  tests/generic/645 | 6 ++++++
> > > >  1 file changed, 6 insertions(+)
> > > > 
> > > > diff --git a/tests/generic/645 b/tests/generic/645
> > > > index d6eb75e6..944b33db 100755
> > > > --- a/tests/generic/645
> > > > +++ b/tests/generic/645
> > > > @@ -19,6 +19,12 @@ _require_chown
> > > >  _wants_kernel_commit dacfd001eaf2 \
> > > >  	"fs/mnt_idmapping.c: Return -EINVAL when no map is written"
> > > >  
> > > > +_free_inodes=$(_get_free_inode $TEST_DIR)
> > > > +if [ $_free_inodes -ne 0 ] && [ $_free_inodes -lt 10001 ]; then
> > > 
> > > I'm assuming the > 0 check here is to cover weird filesystems like fat
> > > that don't advertise any inodes?  /me wonders if that ought to be a
> > 
> > Hey Darrick, sorry I missed this email earlier. Yes that's the idea. I
> > see there is a helper already
> > 
> > _require_inode_limits()
> > {
> > 	if [ $(_get_free_inode $TEST_DIR) -eq 0 ]; then
> > 		_notrun "$FSTYP does not have a fixed number of inodes available"
> > 	fi
> > }
> > 
> > But this will end up skipping the FSes that don't have a concept of
> > free inodes.
> > 
> > > common helper where we can record that justification:
> > > 
> > > _require_free_inodes() {
> > > 	local path="$1"
> > > 	local nr="$2"
> > > 
> > > 	local _free_inodes=$(_get_free_inode "$path")
> > > 
> > > 	# Weird filesystems like vfat don't report any inodes, so we
> > > 	# can't check for sufficient free inodes; IOWs, FAFO.
> > > 	test "$_free_inodes" -eq 0 && return
> > 
> > If we do this, won't we pass the check for the case where say xfs has 0
> > free inodes. It's a rare chance IMObut still wondering if we want to
> > keep that edge case open.
> > 
> > What do you think in these options:
> > - use the above check
> > - use _require_free_inodes which will cause notruns on some FSes
> > - Maybe have a new helper to check if FS advertises free inodes and then
> >   use somthing like
> > 
> >   if ! __fs_advertises_free_inodes
> >     return
> >   else
> >     test "$_free_inodes" -lt "$nr" && \
> >     _notrun "Insufficient free inodes ($_free_inodes), need at least $nr"
> > 
> 
> Hmmm.  This is getting complicated, because generic tests can run on any
> filesystem and we have no idea how much space an inode actually
> consumes, or if the filesystem even has any real concept of inodes.
> 
> Can we instead check the vfstest output for the ENOSPC error message and
> _notrun it if that is found?

Yes this sounds simple enough. The below diff works for me:

  diff --git a/tests/generic/645 b/tests/generic/645
  index d6eb75e6..3d8ca905 100755
  --- a/tests/generic/645
  +++ b/tests/generic/645
  @@ -22,7 +22,14 @@ _wants_kernel_commit dacfd001eaf2 \
   echo "Silence is golden"
  
   $here/src/vfs/vfstest --test-nested-userns \
  -       --device "$TEST_DEV" --mount "$TEST_DIR" --fstype "$FSTYP"
  +       --device "$TEST_DEV" --mount "$TEST_DIR" --fstype "$FSTYP" \
  +       > $tmp.vfstest 2>&1
  
  +if grep -q "No space left on device" $tmp.vfstest; then
  +       _notrun "No space left on device"
  +fi
  +
  +cat $tmp.vfstest
   status=$?

If this looks good I cans send a formal patch.

Regards,
ojaswin 

> 
> --D
> 
> > Regards,
> > ojaswin
> > 
> > > 
> > > 	test "$_free_inodes" -lt "$nr" && \
> > > 		_notrun "Insufficient free inodes ($_free_inodes), need at least $nr"
> > > }
> > > 
> > > 
> > > _require_free_inodes $TEST_DIR 10001
> > > 
> > > (maybe clean up the comment a bit)
> > 
> > > 
> > > --D
> > > 
> > > > +	_notrun "Insufficient free inodes ($_free_inodes), need at least 10001"
> > > > +fi
> > > > +
> > > >  echo "Silence is golden"
> > > >  
> > > >  $here/src/vfs/vfstest --test-nested-userns \
> > > > -- 
> > > > 2.53.0
> > > > 
> > > > 
> >