Re: [PATCH v2 3/9] xfs: ordered buffer log items are never formatted

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

On Tue, Aug 29, 2017 at 10:37:52AM -0400, Brian Foster wrote:
> Ordered buffers pass through the logging infrastructure without ever
> being written to the log. The way this works is that the ordered
> buffer status is transferred to the log vector at commit time via
> the ->iop_size() callback. In xlog_cil_insert_format_items(),
> ordered log vectors bypass ->iop_format() processing altogether.
> 
> Therefore it is unnecessary for xfs_buf_item_format() to handle
> ordered buffers. Remove the unnecessary logic and assert that an
> ordered buffer never reaches this point.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

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

> ---
>  fs/xfs/xfs_buf_item.c | 12 ++----------
>  fs/xfs/xfs_trace.h    |  1 -
>  2 files changed, 2 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
> index ff076d1..ef2c137 100644
> --- a/fs/xfs/xfs_buf_item.c
> +++ b/fs/xfs/xfs_buf_item.c
> @@ -323,6 +323,8 @@ xfs_buf_item_format(
>  	ASSERT((bip->bli_flags & XFS_BLI_STALE) ||
>  	       (xfs_blft_from_flags(&bip->__bli_format) > XFS_BLFT_UNKNOWN_BUF
>  	        && xfs_blft_from_flags(&bip->__bli_format) < XFS_BLFT_MAX_BUF));
> +	ASSERT(!(bip->bli_flags & XFS_BLI_ORDERED) ||
> +	       (bip->bli_flags & XFS_BLI_STALE));
>  
>  
>  	/*
> @@ -347,16 +349,6 @@ xfs_buf_item_format(
>  		bip->bli_flags &= ~XFS_BLI_INODE_BUF;
>  	}
>  
> -	if ((bip->bli_flags & (XFS_BLI_ORDERED|XFS_BLI_STALE)) ==
> -							XFS_BLI_ORDERED) {
> -		/*
> -		 * The buffer has been logged just to order it.  It is not being
> -		 * included in the transaction commit, so don't format it.
> -		 */
> -		trace_xfs_buf_item_format_ordered(bip);
> -		return;
> -	}
> -
>  	for (i = 0; i < bip->bli_format_count; i++) {
>  		xfs_buf_item_format_segment(bip, lv, &vecp, offset,
>  					    &bip->bli_formats[i]);
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 6881047..e839ab4 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -517,7 +517,6 @@ DEFINE_BUF_ITEM_EVENT(xfs_buf_item_size);
>  DEFINE_BUF_ITEM_EVENT(xfs_buf_item_size_ordered);
>  DEFINE_BUF_ITEM_EVENT(xfs_buf_item_size_stale);
>  DEFINE_BUF_ITEM_EVENT(xfs_buf_item_format);
> -DEFINE_BUF_ITEM_EVENT(xfs_buf_item_format_ordered);
>  DEFINE_BUF_ITEM_EVENT(xfs_buf_item_format_stale);
>  DEFINE_BUF_ITEM_EVENT(xfs_buf_item_ordered);
>  DEFINE_BUF_ITEM_EVENT(xfs_buf_item_pin);
> -- 
> 2.9.5
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html