Re: [PATCHv2 1/2] common/rc: Add whitelisted FS support in _require_scratch_swapfile()

[Eryu Guan <guan@eryu.me>]

On Wed, Dec 16, 2020 at 10:53:45AM +0530, Ritesh Harjani wrote:
> 
> 
> On 12/16/20 10:47 AM, Ritesh Harjani wrote:
> > Filesystems e.g. ext4 and XFS supports swapon by default and an error
> > returned with swapon should be treated as a failure. Hence
> > add ext4/xfs as whitelisted fstype in _require_scratch_swapfile()
> > 
> > Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
> > ---
> > v1->v2: Addressed comments from Eryu @[1]
> > [1]: https://patchwork.kernel.org/project/fstests/cover/cover.1604000570.git.riteshh@linux.ibm.com/
> > 
> >   common/rc | 20 ++++++++++++++++----
> >   1 file changed, 16 insertions(+), 4 deletions(-)
> > 
> > diff --git a/common/rc b/common/rc
> > index 33b5b598a198..635b77a005c6 100644
> > --- a/common/rc
> > +++ b/common/rc
> > @@ -2380,6 +2380,7 @@ _format_swapfile() {
> >   # Check that the filesystem supports swapfiles
> >   _require_scratch_swapfile()
> >   {
> > +	local fstyp=$FSTYP
> >   	_require_scratch
> >   	_require_command "$MKSWAP_PROG" "mkswap"
> > 
> > @@ -2401,10 +2402,21 @@ _require_scratch_swapfile()
> >   	# Minimum size for mkswap is 10 pages
> >   	_format_swapfile "$SCRATCH_MNT/swap" $(($(get_page_size) * 10))
> > 
> > -	if ! swapon "$SCRATCH_MNT/swap" >/dev/null 2>&1; then
> > -		_scratch_unmount
> > -		_notrun "swapfiles are not supported"
> > -	fi
> > +	# For whitelisted fstyp swapon should not fail.
> > +	case "$fstyp" in
> > +	ext4|xfs)
> > +		if ! swapon "$SCRATCH_MNT/swap" >/dev/null 2>&1; then
> > +			_scratch_unmount
> > +			_fail "swapon failed for $fstyp"
> 
> @Eryu,
> As of now I added _fail() if swapon failed for given whitelisting fstype.
> Do you think this is alright, or should I just ignore the error in

I think it's reasonable.

But I'd like to leave the patchset on the list for review for another
week, to see if ext4 and/or xfs folks will chime in and have different
thoughts.

Thanks,
Eryu

> case of such FS?
> 
> 
> 
> > +		fi
> > +		;;
> > +	*)
> > +		if ! swapon "$SCRATCH_MNT/swap" >/dev/null 2>&1; then
> > +			_scratch_unmount
> > +			_notrun "swapfiles are not supported"
> > +		fi
> > +		;;
> > +	esac
> > 
> >   	swapoff "$SCRATCH_MNT/swap" >/dev/null 2>&1
> >   	_scratch_unmount
> > --
> > 2.26.2
> >