Re: [PATCH v8 5/5] xfs: add error injection for per-AG resv failure

[Gao Xiang <hsiangkao@redhat.com>]

On Tue, Mar 09, 2021 at 10:05:03AM -0800, Darrick J. Wong wrote:
> On Fri, Mar 05, 2021 at 10:57:03AM +0800, Gao Xiang wrote:
> > per-AG resv failure after fixing up freespace is hard to test in an
> > effective way, so directly add an error injection path to observe
> > such error handling path works as expected.
> > 
> > Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> > ---
> >  fs/xfs/libxfs/xfs_ag_resv.c  | 6 +++++-
> >  fs/xfs/libxfs/xfs_errortag.h | 4 +++-
> >  fs/xfs/xfs_error.c           | 3 +++
> >  3 files changed, 11 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c
> > index fdfe6dc0d307..6c5f8d10589c 100644
> > --- a/fs/xfs/libxfs/xfs_ag_resv.c
> > +++ b/fs/xfs/libxfs/xfs_ag_resv.c
> > @@ -211,7 +211,11 @@ __xfs_ag_resv_init(
> >  		ASSERT(0);
> >  		return -EINVAL;
> >  	}
> > -	error = xfs_mod_fdblocks(mp, -(int64_t)hidden_space, true);
> > +
> > +	if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_AG_RESV_FAIL))
> > +		error = -ENOSPC;
> > +	else
> > +		error = xfs_mod_fdblocks(mp, -(int64_t)hidden_space, true);
> >  	if (error) {
> >  		trace_xfs_ag_resv_init_error(pag->pag_mount, pag->pag_agno,
> >  				error, _RET_IP_);
> > diff --git a/fs/xfs/libxfs/xfs_errortag.h b/fs/xfs/libxfs/xfs_errortag.h
> > index 6ca9084b6934..a23a52e643ad 100644
> > --- a/fs/xfs/libxfs/xfs_errortag.h
> > +++ b/fs/xfs/libxfs/xfs_errortag.h
> > @@ -58,7 +58,8 @@
> >  #define XFS_ERRTAG_BUF_IOERROR				35
> >  #define XFS_ERRTAG_REDUCE_MAX_IEXTENTS			36
> >  #define XFS_ERRTAG_BMAP_ALLOC_MINLEN_EXTENT		37
> > -#define XFS_ERRTAG_MAX					38
> > +#define XFS_ERRTAG_AG_RESV_FAIL				38
> > +#define XFS_ERRTAG_MAX					39
> >  
> >  /*
> >   * Random factors for above tags, 1 means always, 2 means 1/2 time, etc.
> > @@ -101,5 +102,6 @@
> >  #define XFS_RANDOM_BUF_IOERROR				XFS_RANDOM_DEFAULT
> >  #define XFS_RANDOM_REDUCE_MAX_IEXTENTS			1
> >  #define XFS_RANDOM_BMAP_ALLOC_MINLEN_EXTENT		1
> > +#define XFS_RANDOM_AG_RESV_FAIL				1
> >  
> >  #endif /* __XFS_ERRORTAG_H_ */
> > diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
> > index 185b4915b7bf..f70984f3174d 100644
> > --- a/fs/xfs/xfs_error.c
> > +++ b/fs/xfs/xfs_error.c
> > @@ -56,6 +56,7 @@ static unsigned int xfs_errortag_random_default[] = {
> >  	XFS_RANDOM_BUF_IOERROR,
> >  	XFS_RANDOM_REDUCE_MAX_IEXTENTS,
> >  	XFS_RANDOM_BMAP_ALLOC_MINLEN_EXTENT,
> > +	XFS_RANDOM_AG_RESV_FAIL,
> >  };
> 
> Could you please add the BUILD_BUG_ON somewhere in xfs_error.c to make
> sure that the length of xfs_errortag_random_default matches
> XFS_ERRTAG_MAX?  I inquired about that in the v7 series review, but that
> seems not to have been addressed?

Ah, sorry, I didn't get the point. I've sent out a seperate patch
to address this, please kindly check:
https://lore.kernel.org/r/20210309184205.18675-1-hsiangkao@aol.com

Thanks,
Gao Xiang

> 
> --D
> 
> >  
> >  struct xfs_errortag_attr {
> > @@ -168,6 +169,7 @@ XFS_ERRORTAG_ATTR_RW(iunlink_fallback,	XFS_ERRTAG_IUNLINK_FALLBACK);
> >  XFS_ERRORTAG_ATTR_RW(buf_ioerror,	XFS_ERRTAG_BUF_IOERROR);
> >  XFS_ERRORTAG_ATTR_RW(reduce_max_iextents,	XFS_ERRTAG_REDUCE_MAX_IEXTENTS);
> >  XFS_ERRORTAG_ATTR_RW(bmap_alloc_minlen_extent,	XFS_ERRTAG_BMAP_ALLOC_MINLEN_EXTENT);
> > +XFS_ERRORTAG_ATTR_RW(ag_resv_fail, XFS_ERRTAG_AG_RESV_FAIL);
> >  
> >  static struct attribute *xfs_errortag_attrs[] = {
> >  	XFS_ERRORTAG_ATTR_LIST(noerror),
> > @@ -208,6 +210,7 @@ static struct attribute *xfs_errortag_attrs[] = {
> >  	XFS_ERRORTAG_ATTR_LIST(buf_ioerror),
> >  	XFS_ERRORTAG_ATTR_LIST(reduce_max_iextents),
> >  	XFS_ERRORTAG_ATTR_LIST(bmap_alloc_minlen_extent),
> > +	XFS_ERRORTAG_ATTR_LIST(ag_resv_fail),
> >  	NULL,
> >  };
> >  
> > -- 
> > 2.27.0
> > 
>