Re: [PATCH 3/3] xfs: RT bitmap and summary buffers need verifiers

Eric Sandeen
2016-02-02T01:25:30Z

On 2/1/16 6:39 PM, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Buffers without verifiers issue runtime warnings on XFS. We don't
> have anything we can actually verify in the RT buffers (no CRCs, not
> magic numbers, etc), but we still need verifiers to avoid the
> warnings.
>
> Add a set of dummy verifier operations for the realtime buffers and
> apply them in the appropriate places.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
> fs/xfs/libxfs/xfs_rtbitmap.c | 27 ++++++++++++++++++++++++++-
> fs/xfs/libxfs/xfs_shared.h | 1 +
> fs/xfs/xfs_log_recover.c | 4 ++--
> 3 files changed, 29 insertions(+), 3 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c
> index bfa7b85..01c0cdb 100644
> --- a/fs/xfs/libxfs/xfs_rtbitmap.c
> +++ b/fs/xfs/libxfs/xfs_rtbitmap.c
> @@ -42,6 +42,31 @@
> */
>
> /*
> + * Real time buffers need verifiers to avoid runtime warnigns during IO.

"warnings" ;)

Otherwise:
Reviewed-by: Eric Sandeen <sandeen@redhat.com>

> + * We don't have anything to verify, however, so these are just dummy
> + * operations.
> + */
> +static void
> +xfs_rtbuf_verify_read(
> + struct xfs_buf *bp)
> +{
> + return;
> +}
> +
> +static void
> +xfs_rtbuf_verify_write(
> + struct xfs_buf *bp)
> +{
> + return;
> +}
> +
> +const struct xfs_buf_ops xfs_rtbuf_ops = {
> + .name = "rtbuf",
> + .verify_read = xfs_rtbuf_verify_read,
> + .verify_write = xfs_rtbuf_verify_write,
> +};
> +
> +/*
> * Get a buffer for the bitmap or summary file block specified.
> * The buffer is returned read and locked.
> */
> @@ -68,7 +93,7 @@ xfs_rtbuf_get(
> ASSERT(map.br_startblock != NULLFSBLOCK);
> error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
> XFS_FSB_TO_DADDR(mp, map.br_startblock),
> - mp->m_bsize, 0, &bp, NULL);
> + mp->m_bsize, 0, &bp, &xfs_rtbuf_ops);
> if (error)
> return error;
>
> diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
> index 15c3ceb..81ac870 100644
> --- a/fs/xfs/libxfs/xfs_shared.h
> +++ b/fs/xfs/libxfs/xfs_shared.h
> @@ -53,6 +53,7 @@ extern const struct xfs_buf_ops xfs_dquot_buf_ra_ops;
> extern const struct xfs_buf_ops xfs_sb_buf_ops;
> extern const struct xfs_buf_ops xfs_sb_quiet_buf_ops;
> extern const struct xfs_buf_ops xfs_symlink_buf_ops;
> +extern const struct xfs_buf_ops xfs_rtbuf_ops;
>
> /*
> * Transaction types. Used to distinguish types of buffers. These never reach
> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
> index e2d7533..9d09a0d 100644
> --- a/fs/xfs/xfs_log_recover.c
> +++ b/fs/xfs/xfs_log_recover.c
> @@ -2475,8 +2475,8 @@ xlog_recover_validate_buf_type(
> break;
> case XFS_BLFT_RTBITMAP_BUF:
> case XFS_BLFT_RTSUMMARY_BUF:
> - /* no verification of RT buffers is done */
> - bp->b_ops = NULL;
> + /* no magic numbers for verification of RT buffers */
> + bp->b_ops = &xfs_rtbuf_ops;
> break;
> default:
> xfs_warn(mp, "Unknown buffer type %d!",