Re: [PATCH v3 15/17] xfs: random buffer write failure errortag

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

On Wed, Apr 29, 2020 at 01:21:51PM -0400, Brian Foster wrote:
> Introduce an error tag to randomly fail async buffer writes. This is
> primarily to facilitate testing of the XFS error configuration
> mechanism.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> Reviewed-by: Allison Collins <allison.henderson@oracle.com>
> Reviewed-by: Dave Chinner <dchinner@redhat.com>

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/libxfs/xfs_errortag.h | 4 +++-
>  fs/xfs/xfs_buf.c             | 6 ++++++
>  fs/xfs/xfs_error.c           | 3 +++
>  3 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_errortag.h b/fs/xfs/libxfs/xfs_errortag.h
> index 79e6c4fb1d8a..2486dab19023 100644
> --- a/fs/xfs/libxfs/xfs_errortag.h
> +++ b/fs/xfs/libxfs/xfs_errortag.h
> @@ -55,7 +55,8 @@
>  #define XFS_ERRTAG_FORCE_SCRUB_REPAIR			32
>  #define XFS_ERRTAG_FORCE_SUMMARY_RECALC			33
>  #define XFS_ERRTAG_IUNLINK_FALLBACK			34
> -#define XFS_ERRTAG_MAX					35
> +#define XFS_ERRTAG_BUF_IOERROR				35
> +#define XFS_ERRTAG_MAX					36
>  
>  /*
>   * Random factors for above tags, 1 means always, 2 means 1/2 time, etc.
> @@ -95,5 +96,6 @@
>  #define XFS_RANDOM_FORCE_SCRUB_REPAIR			1
>  #define XFS_RANDOM_FORCE_SUMMARY_RECALC			1
>  #define XFS_RANDOM_IUNLINK_FALLBACK			(XFS_RANDOM_DEFAULT/10)
> +#define XFS_RANDOM_BUF_IOERROR				XFS_RANDOM_DEFAULT
>  
>  #endif /* __XFS_ERRORTAG_H_ */
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index 8f0f605de579..61629efd56ee 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -1289,6 +1289,12 @@ xfs_buf_bio_end_io(
>  	struct bio		*bio)
>  {
>  	struct xfs_buf		*bp = (struct xfs_buf *)bio->bi_private;
> +	struct xfs_mount	*mp = bp->b_mount;
> +
> +	if (!bio->bi_status &&
> +	    (bp->b_flags & XBF_WRITE) && (bp->b_flags & XBF_ASYNC) &&
> +	    XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BUF_IOERROR))
> +		bio->bi_status = BLK_STS_IOERR;
>  
>  	/*
>  	 * don't overwrite existing errors - otherwise we can lose errors on
> diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
> index a21e9cc6516a..7f6e20899473 100644
> --- a/fs/xfs/xfs_error.c
> +++ b/fs/xfs/xfs_error.c
> @@ -53,6 +53,7 @@ static unsigned int xfs_errortag_random_default[] = {
>  	XFS_RANDOM_FORCE_SCRUB_REPAIR,
>  	XFS_RANDOM_FORCE_SUMMARY_RECALC,
>  	XFS_RANDOM_IUNLINK_FALLBACK,
> +	XFS_RANDOM_BUF_IOERROR,
>  };
>  
>  struct xfs_errortag_attr {
> @@ -162,6 +163,7 @@ XFS_ERRORTAG_ATTR_RW(buf_lru_ref,	XFS_ERRTAG_BUF_LRU_REF);
>  XFS_ERRORTAG_ATTR_RW(force_repair,	XFS_ERRTAG_FORCE_SCRUB_REPAIR);
>  XFS_ERRORTAG_ATTR_RW(bad_summary,	XFS_ERRTAG_FORCE_SUMMARY_RECALC);
>  XFS_ERRORTAG_ATTR_RW(iunlink_fallback,	XFS_ERRTAG_IUNLINK_FALLBACK);
> +XFS_ERRORTAG_ATTR_RW(buf_ioerror,	XFS_ERRTAG_BUF_IOERROR);
>  
>  static struct attribute *xfs_errortag_attrs[] = {
>  	XFS_ERRORTAG_ATTR_LIST(noerror),
> @@ -199,6 +201,7 @@ static struct attribute *xfs_errortag_attrs[] = {
>  	XFS_ERRORTAG_ATTR_LIST(force_repair),
>  	XFS_ERRORTAG_ATTR_LIST(bad_summary),
>  	XFS_ERRORTAG_ATTR_LIST(iunlink_fallback),
> +	XFS_ERRORTAG_ATTR_LIST(buf_ioerror),
>  	NULL,
>  };
>  
> -- 
> 2.21.1
>