On Wed, Jul 15, 2020 at 01:55:14PM +0800, Xiao Yang wrote:
> On 2020/7/15 12:15, Ira Weiny wrote:
> > On Wed, Jul 15, 2020 at 11:19:58AM +0800, Xiao Yang wrote:
> > > On 2020/7/15 9:59, Ira Weiny wrote:
> > > > On Tue, Jul 14, 2020 at 05:40:03PM +0800, Xiao Yang wrote:
> > > > > 1) _require_scratch_dax_mountopt() checks both old and new DAX mount option
> > > > > 2) _require_dax_iflag() checks FS_XFLAG_DAX
> > > > >
> > > > > Signed-off-by: Xiao Yang<yangx.jy@xxxxxxxxxxxxxx>
> > > > Reviewed-by: Ira Weiny<ira.weiny@xxxxxxxxx>
> > > Hi Ira,
> > >
> > > Do you want to check if invalid parameter is passed to
> > > _require_scratch_dax_mountopt? Thought
> > > I think it is not necessary(user should pass correct parament).
> > > Like this:
> > > [ "$mountopt" != "dax" ]&& [ "$mountopt" != "dax=always" ]&& _notrun
> > > "$mountopt is invalid"
> > I thought this patch was just checking if the filesystem/device supported DAX
> > such that DAX tests could run using either old _or_ new dax support...
> > But after thinking about it I think we need something more complicated.
> >
> > Something like:
> >
> > if ('-o dax=inode')
> > // FS is DAX with per file support (ie ext4 || XFS kernel>= 5.8)
> Hi Ira,
>
> dax=inode/dax=never cannot check if underlying device supports dax, so I
> perfer to use dax=always
> For example:
> XFS:
> # mount -o dax=inode /dev/sda8 /mnt/xfstests/test/
> # mount | grep sda8
> /dev/sda8 on /mnt/xfstests/test type xfs
> (rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota)
> ...
> # mount -o dax=always /dev/sda8 /mnt/xfstests/test/
> # mount | grep sda8
> /dev/sda8 on /mnt/xfstests/test type xfs
> (rw,relatime,seclabel,attr2,dax=never,inode64,logbufs=8,logbsize=32k,noquota)
>
> EXT4:
> # mount -o dax=inode /dev/sda8 /mnt/xfstests/test/
> # mount | grep sda8
> /dev/sda8 on /mnt/xfstests/test type ext4 (rw,relatime,seclabel,dax=inode)
> ...
> # mount -o dax=always /dev/sda8 /mnt/xfstests/test/
> mount: /mnt/xfstests/test: wrong fs type, bad option, bad superblock on
> /dev/sda8, missing codepage or helper program, or other error.
> # dmesg | grep DAX
> [597988.165120] EXT4-fs (sda8): DAX unsupported by block device.
>
> If we want to test new dax(i.e. dax=inode, dax=always or dax=never), so pass
> "dax=always" to _require_scratch_dax_mountopt
> If we want to test old dax or new dax=always(either of them), so pass "dax"
> to _require_scratch_dax_mountopt
That does seem like the only way to figure out if a fs/device
combination supports dax.
The valid arguments to the _require_scratch_dax* helpers are worth
mentioning in a comment above the function, but I suspect that adding
validation code is probably overkill.
--D
> Best Regards,
> Xiao Yang
> > else if ('-o dax')
> > // FS is DAX (ie ext4 || XFS on kernel< 5.8)
> > else
> > // FS has no dax support.
> >
> > Do we do that with 2 functions?
> >
> > _require_scratch_dax_mountopt()
> > _require_scratch_new_dax_mountopt()
> >
> > If both fail we are in the else clause above?
> >
> > We can use the dax=inode because it is a new option and is not necessarily the
> > option used while running the tests. (I think. as I said my xfstests skills
> > are not great so I'm not always sure of the correct patterns)
> >
> > Ira
> >
> > > Best Regards,
> > > Xiao Yang
> > > > > ---
> > > > >
> > > > > V5->V6:
> > > > > Simplify _require_scratch_dax_mountopt because it is enough to only check
> > > > > dax/dax=always mount option. See the following reasons:
> > > > > 1) we cannot detect if underlying device supports dax by mounting dax=inode
> > > > > or dax=never.
> > > > > 2) dax=always, dax=inode, dax=never are always introduced together.
> > > > >
> > > > > common/rc | 22 ++++++++++++++++++++++
> > > > > 1 file changed, 22 insertions(+)
> > > > >
> > > > > diff --git a/common/rc b/common/rc
> > > > > index f17b19f2..aeec1f11 100644
> > > > > --- a/common/rc
> > > > > +++ b/common/rc
> > > > > @@ -3188,6 +3188,28 @@ _require_scratch_dax()
> > > > > _scratch_unmount
> > > > > }
> > > > >
> > > > > +# Only accept dax/dax=always mount option becasue dax=always, dax=inode
> > > > > +# and dax=never are always introduced together.
> > > > > +_require_scratch_dax_mountopt()
> > > > > +{
> > > > > + local mountopt=$1
> > > > > +
> > > > > + _require_scratch
> > > > > + _scratch_mkfs> /dev/null 2>&1
> > > > > + _try_scratch_mount "-o $mountopt"> /dev/null 2>&1 || \
> > > > > + _notrun "mount $SCRATCH_DEV with $mountopt failed"
> > > > > +
> > > > > + _fs_options $SCRATCH_DEV | egrep -q "dax(=always|,|$)" || \
> > > > > + _notrun "$SCRATCH_DEV $FSTYP does not support -o $mountopt"
> > > > > +
> > > > > + _scratch_unmount
> > > > > +}
> > > > > +
> > > > > +_require_dax_iflag()
> > > > > +{
> > > > > + _require_xfs_io_command "chattr" "x"
> > > > > +}
> > > > > +
> > > > > # Does norecovery support by this fs?
> > > > > _require_norecovery()
> > > > > {
> > > > > --
> > > > > 2.21.0
> > > > >
> > > > >
> > > > >
> > > > .
> > > >
> > >
> > >
> >
> > .
> >
>
>
>
