Re: [PATCH 11/12] mkfs: validate start and end of aligned logs

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Tue, May 21, 2019 at 02:24:40PM -0500, Eric Sandeen wrote:
> On 5/20/19 6:17 PM, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Validate that the start and end of the log stay within a single AG if
> > we adjust either end to align to stripe units.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  mkfs/xfs_mkfs.c |   15 ++++++++++++++-
> >  1 file changed, 14 insertions(+), 1 deletion(-)
> > 
> > 
> > diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> > index 5b66074d..8f84536e 100644
> > --- a/mkfs/xfs_mkfs.c
> > +++ b/mkfs/xfs_mkfs.c
> > @@ -3044,15 +3044,28 @@ align_internal_log(
> >  	struct xfs_mount	*mp,
> >  	int			sunit)
> >  {
> > +	uint64_t		logend;
> > +
> >  	/* round up log start if necessary */
> >  	if ((cfg->logstart % sunit) != 0)
> >  		cfg->logstart = ((cfg->logstart + (sunit - 1)) / sunit) * sunit;
> >  
> > +	/* if our log start rounds into the next AG we're done */
> 
> /* If our log start overlaps the next AG's metadata, fail */

Ok.

> > +	if (!xfs_verify_fsbno(mp, cfg->logstart)) {
> > +			fprintf(stderr,
> > +_("Due to stripe alignment, the internal log start (%lld) cannot be aligned\n"
> > +  "within an allocation group.\n"),
> > +			(long long) cfg->logstart);
> 
> Hm, should it suggest what should be modified to try again ...?

But what should be modified, exactly?  -d su=0,sw=0?

> > +		usage();
> > +	}
> > +
> >  	/* round up/down the log size now */
> >  	align_log_size(cfg, sunit);
> >  
> >  	/* check the aligned log still fits in an AG. */
> > -	if (cfg->logblocks > cfg->agsize - XFS_FSB_TO_AGBNO(mp, cfg->logstart)) {
> > +	logend = cfg->logstart + cfg->logblocks - 1;
> > +	if (XFS_FSB_TO_AGNO(mp, cfg->logstart) != XFS_FSB_TO_AGNO(mp, logend) ||
> > +	    !xfs_verify_fsbno(mp, logend)) {
> 
> this xfs_verify_fsbno is probably redundant but can't hurt?

<nod>

Will respin patch.

--D

> -Eric
> 
> >  		fprintf(stderr,
> >  _("Due to stripe alignment, the internal log size (%lld) is too large.\n"
> >    "Must fit within an allocation group.\n"),
> >