Re: [PATCH 1/2] common/dmlogwrites: add _require_logwrites_size helper

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Apr 22, 2026 at 11:08:34AM +0530, Disha Goel wrote:
> Hi,
> 
> Looking for review comments on this patch series.
> 
> On 14/04/26 3:50 pm, Disha Goel wrote:
> > Add a new helper function _require_logwrites_size() to check if the
> > LOGWRITES_DEV meets a minimum size requirement.
> > 
> > This is useful for tests that use dm-log-writes with additional space
> > requirements, such as creating LVM snapshots during log replay or tests
> > that generate large amounts of logged I/O operations.
> > 
> > The function takes a size parameter in KB and skips the test if
> > LOGWRITES_DEV is smaller than the required size.
> > 
> > Signed-off-by: Disha Goel <disgoel@linux.ibm.com>
> > ---
> >   common/dmlogwrites | 9 +++++++++
> >   1 file changed, 9 insertions(+)
> > 
> > diff --git a/common/dmlogwrites b/common/dmlogwrites
> > index a27e1966..1ce2b2fb 100644
> > --- a/common/dmlogwrites
> > +++ b/common/dmlogwrites
> > @@ -14,6 +14,15 @@ _require_log_writes()
> >   	_require_test_program "log-writes/replay-log"
> >   }
> > +_require_logwrites_size()
> > +{
> > +        [ $# -eq 1 ] || _fail "_require_logwrites_size: expected size param"

What are the units of the size parameter?  Bytes?  512b sectors?

The helper should have a comment clarifying that.

--D

> > +
> > +        local devsize=$(_get_device_size $LOGWRITES_DEV)
> > +        [ $devsize -lt $1 ] && \
> > +                _notrun "LOGWRITES_DEV too small, ${devsize}KB < $1KB"
> > +}
> > +
> >   # Starting from v4.15-rc1, DAX support was added to dm-log-writes, but note
> >   # that it doesn't track the data that we write via the mmap(), so we can't do
> >   # any data integrity checking. We can only verify that the metadata writes for
> 
> -- 
> Regards,
> Disha
> 
>